TODO: docs

squash this into the commit that first added all_tests.ts, we don't even
want to have a trace of it left

for the cli ones, we can simply iterate the filesystem relative our
location. for the web one, we determine it on launch and expose it as an
endpoint from the server which the client queries

.clang-format

@@ -0,0 +1,2 @@
+ColumnLimit: 0
+IndentWidth: 4

.gitea/workflows/test.yml

@@ -2,7 +2,6 @@ name: Test
 
 on:
   - push
-  - pull_request
 
 jobs:
   hakurei:
@@ -73,20 +72,20 @@ jobs:
           path: result/*
           retention-days: 1
 
-  planterette:
-    name: Planterette
+  sharefs:
+    name: ShareFS
     runs-on: nix
     steps:
       - name: Checkout
         uses: actions/checkout@v4
 
       - name: Run NixOS test
-        run: nix build --out-link "result" --print-out-paths --print-build-logs .#checks.x86_64-linux.planterette
+        run: nix build --out-link "result" --print-out-paths --print-build-logs .#checks.x86_64-linux.sharefs
 
       - name: Upload test output
         uses: actions/upload-artifact@v3
         with:
-          name: "planterette-vm-output"
+          name: "sharefs-vm-output"
           path: result/*
           retention-days: 1
 
@@ -97,7 +96,7 @@ jobs:
       - race
       - sandbox
       - sandbox-race
-      - planterette
+      - sharefs
     runs-on: nix
     steps:
       - name: Checkout

.github/workflows/README

@@ -1 +0,0 @@
-This port is solely for releasing to the github mirror and serves no purpose during development.

.github/workflows/release.yml

@@ -1,46 +0,0 @@
-name: Release
-
-on:
-  push:
-    tags:
-      - 'v*'
-
-jobs:
-  release:
-    name: Create release
-    runs-on: ubuntu-latest
-
-    permissions:
-      packages: write
-      contents: write
-
-    steps:
-      - name: Checkout
-        uses: actions/checkout@v4
-
-      - name: Install Nix
-        uses: nixbuild/nix-quick-install-action@v32
-        with:
-          nix_conf: |
-            keep-env-derivations = true
-            keep-outputs = true
-
-      - name: Restore and cache Nix store
-        uses: nix-community/cache-nix-action@v6
-        with:
-          primary-key: build-${{ runner.os }}-${{ hashFiles('**/*.nix') }}
-          restore-prefixes-first-match: build-${{ runner.os }}-
-          gc-max-store-size-linux: 1G
-          purge: true
-          purge-prefixes: build-${{ runner.os }}-
-          purge-created: 60
-          purge-primary-key: never
-
-      - name: Build for release
-        run: nix build --print-out-paths --print-build-logs .#dist
-
-      - name: Release
-        uses: softprops/action-gh-release@v2
-        with:
-          files: |-
-            result/hakurei-**

.github/workflows/test.yml

@@ -1,48 +0,0 @@
-name: Test
-
-on:
-  - push
-
-jobs:
-  dist:
-    name: Create distribution
-    runs-on: ubuntu-latest
-    permissions:
-      actions: write
-    steps:
-      - name: Checkout
-        uses: actions/checkout@v4
-
-      - name: Install Nix
-        uses: nixbuild/nix-quick-install-action@v32
-        with:
-          nix_conf: |
-            keep-env-derivations = true
-            keep-outputs = true
-
-      - name: Restore and cache Nix store
-        uses: nix-community/cache-nix-action@v6
-        with:
-          primary-key: build-${{ runner.os }}-${{ hashFiles('**/*.nix') }}
-          restore-prefixes-first-match: build-${{ runner.os }}-
-          gc-max-store-size-linux: 1G
-          purge: true
-          purge-prefixes: build-${{ runner.os }}-
-          purge-created: 60
-          purge-primary-key: never
-
-      - name: Build for test
-        id: build-test
-        run: >-
-          export HAKUREI_REV="$(git rev-parse --short HEAD)" &&
-          sed -i.old 's/version = /version = "0.0.0-'$HAKUREI_REV'"; # version = /' package.nix &&
-          nix build --print-out-paths --print-build-logs .#dist &&
-          mv package.nix.old package.nix &&
-          echo "rev=$HAKUREI_REV" >> $GITHUB_OUTPUT
-
-      - name: Upload test build
-        uses: actions/upload-artifact@v4
-        with:
-          name: "hakurei-${{ steps.build-test.outputs.rev }}"
-          path: result/*
-          retention-days: 1

.gitignore

@@ -1,32 +1,15 @@
-# Binaries for programs and plugins
-*.exe
-*.exe~
-*.dll
-*.so
-*.dylib
-*.pkg
-/hakurei
-
-# Test binary, built with `go test -c`
+# produced by tools and text editors
+*.qcow2
 *.test
-
-# Output of the go coverage tool, specifically when used with LiteIDE
 *.out
-
-# Dependency directories (remove the comment below to include it)
-# vendor/
-
-# Go workspace file
-go.work
-go.work.sum
-
-# env file
-.env
 .idea
 .vscode
 
 # go generate
 /cmd/hakurei/LICENSE
+/cmd/mbf/internal/pkgserver/ui/static
+/internal/pkg/internal/testtool/testtool
+/internal/rosa/hakurei_current.tar.gz
 
-# release
-/dist/hakurei-*
+# cmd/dist default destination
+/dist

README.md

@@ -1,5 +1,5 @@
 <p align="center">
-  <a href="https://git.gensokyo.uk/security/hakurei">
+  <a href="https://git.gensokyo.uk/rosa/hakurei">
     <picture>
       <img src="https://basement.gensokyo.uk/images/yukari1.png" width="200px" alt="Yukari">
     </picture>
@@ -8,170 +8,58 @@
 
 <p align="center">
   <a href="https://pkg.go.dev/hakurei.app"><img src="https://pkg.go.dev/badge/hakurei.app.svg" alt="Go Reference" /></a>
-  <a href="https://git.gensokyo.uk/security/hakurei/actions"><img src="https://git.gensokyo.uk/security/hakurei/actions/workflows/test.yml/badge.svg?branch=staging&style=flat-square" alt="Gitea Workflow Status" /></a>
+  <a href="https://git.gensokyo.uk/rosa/hakurei/actions"><img src="https://git.gensokyo.uk/rosa/hakurei/actions/workflows/test.yml/badge.svg?branch=staging&style=flat-square" alt="Gitea Workflow Status" /></a>
   <br/>
-  <a href="https://git.gensokyo.uk/security/hakurei/releases"><img src="https://img.shields.io/gitea/v/release/security/hakurei?gitea_url=https%3A%2F%2Fgit.gensokyo.uk&color=purple" alt="Release" /></a>
+  <a href="https://git.gensokyo.uk/rosa/hakurei/releases"><img src="https://img.shields.io/gitea/v/release/rosa/hakurei?gitea_url=https%3A%2F%2Fgit.gensokyo.uk&color=purple" alt="Release" /></a>
   <a href="https://goreportcard.com/report/hakurei.app"><img src="https://goreportcard.com/badge/hakurei.app" alt="Go Report Card" /></a>
   <a href="https://hakurei.app"><img src="https://img.shields.io/website?url=https%3A%2F%2Fhakurei.app" alt="Website" /></a>
 </p>
 
-Hakurei is a tool for running sandboxed graphical applications as dedicated subordinate users on the Linux kernel.
-It also implements [planterette (WIP)](cmd/planterette), a self-contained Android-like package manager with modern security features.
+Hakurei is a tool for running sandboxed desktop applications as dedicated
+subordinate users on the Linux kernel. It implements the application container
+of [planterette (WIP)](https://git.gensokyo.uk/rosa/planterette), a
+self-contained Android-like package manager with modern security features.
 
-## NixOS Module usage
+Interaction with hakurei happens entirely through structures described by
+package [hst](https://pkg.go.dev/hakurei.app/hst). No native API is available
+due to internal details of uid isolation.
 
-The NixOS module currently requires home-manager to configure subordinate users. Full module documentation can be found [here](options.md).
+## Notable Packages
 
-To use the module, import it into your configuration with
+Package [container](https://pkg.go.dev/hakurei.app/container) is general purpose
+container tooling. It is used by the hakurei shim process running as the target
+subordinate user to set up the application container. It has a single dependency,
+[libseccomp](https://github.com/seccomp/libseccomp), to create BPF programs
+for the [system call filter](https://www.kernel.org/doc/html/latest/userspace-api/seccomp_filter.html).
 
-```nix
-{
-  inputs = {
-    nixpkgs.url = "github:NixOS/nixpkgs/nixos-24.11";
+Package [internal/pkg](https://pkg.go.dev/hakurei.app/internal/pkg) provides
+infrastructure for hermetic builds. This replaces the legacy nix-based testing
+framework and serves as the build system of Rosa OS, currently developed under
+package [internal/rosa](https://pkg.go.dev/hakurei.app/internal/rosa).
 
-    hakurei = {
-      url = "git+https://git.gensokyo.uk/security/hakurei";
+## Dependencies
 
-      # Optional but recommended to limit the size of your system closure.
-      inputs.nixpkgs.follows = "nixpkgs";
-    };
-  };
+`container` depends on:
 
-  outputs = { self, nixpkgs, hakurei, ... }:
-  {
-    nixosConfigurations.hakurei = nixpkgs.lib.nixosSystem {
-      system = "x86_64-linux";
-      modules = [
-        hakurei.nixosModules.hakurei
-      ];
-    };
-  };
-}
-```
+- [libseccomp](https://github.com/seccomp/libseccomp) to generate BPF programs.
 
-This adds the `environment.hakurei` option:
+`cmd/hakurei` depends on:
 
-```nix
-{ pkgs, ... }:
+- [acl](https://savannah.nongnu.org/projects/acl/) to export sockets to
+  subordinate users.
+- [wayland](https://gitlab.freedesktop.org/wayland/wayland) to set up
+  [security-context-v1](https://wayland.app/protocols/security-context-v1).
+- [xcb](https://xcb.freedesktop.org/) to grant and revoke subordinate users
+  access to the X server.
 
-{
-  environment.hakurei = {
-    enable = true;
-    stateDir = "/var/lib/hakurei";
-    users = {
-      alice = 0;
-      nixos = 10;
-    };
+`cmd/sharefs` depends on:
 
-    commonPaths = [
-      {
-        src = "/sdcard";
-        write = true;
-      }
-    ];
+- [fuse](https://github.com/libfuse/libfuse) to implement the filesystem.
 
-    extraHomeConfig = {
-      home.stateVersion = "23.05";
-    };
+New dependencies will generally not be added. Patches adding new dependencies
+are very likely to be rejected.
 
-    apps = {
-      "org.chromium.Chromium" = {
-        name = "chromium";
-        identity = 1;
-        packages = [ pkgs.chromium ];
-        userns = true;
-        mapRealUid = true;
-        dbus = {
-          system = {
-            filter = true;
-            talk = [
-              "org.bluez"
-              "org.freedesktop.Avahi"
-              "org.freedesktop.UPower"
-            ];
-          };
-          session =
-            f:
-            f {
-              talk = [
-                "org.freedesktop.FileManager1"
-                "org.freedesktop.Notifications"
-                "org.freedesktop.ScreenSaver"
-                "org.freedesktop.secrets"
-                "org.kde.kwalletd5"
-                "org.kde.kwalletd6"
-              ];
-              own = [
-                "org.chromium.Chromium.*"
-                "org.mpris.MediaPlayer2.org.chromium.Chromium.*"
-                "org.mpris.MediaPlayer2.chromium.*"
-              ];
-              call = { };
-              broadcast = { };
-            };
-        };
-      };
+## NixOS Module (deprecated)
 
-      "org.claws_mail.Claws-Mail" = {
-        name = "claws-mail";
-        identity = 2;
-        packages = [ pkgs.claws-mail ];
-        gpu = false;
-        capability.pulse = false;
-      };
-
-      "org.weechat" = {
-        name = "weechat";
-        identity = 3;
-        shareUid = true;
-        packages = [ pkgs.weechat ];
-        capability = {
-          wayland = false;
-          x11 = false;
-          dbus = true;
-          pulse = false;
-        };
-      };
-
-      "dev.vencord.Vesktop" = {
-        name = "discord";
-        identity = 3;
-        shareUid = true;
-        packages = [ pkgs.vesktop ];
-        share = pkgs.vesktop;
-        command = "vesktop --ozone-platform-hint=wayland";
-        userns = true;
-        mapRealUid = true;
-        capability.x11 = true;
-        dbus = {
-          session =
-            f:
-            f {
-              talk = [ "org.kde.StatusNotifierWatcher" ];
-              own = [ ];
-              call = { };
-              broadcast = { };
-            };
-          system.filter = true;
-        };
-      };
-
-      "io.looking-glass" = {
-        name = "looking-glass-client";
-        identity = 4;
-        useCommonPaths = false;
-        groups = [ "plugdev" ];
-        extraPaths = [
-          {
-            src = "/dev/shm/looking-glass";
-            write = true;
-          }
-        ];
-        extraConfig = {
-          programs.looking-glass-client.enable = true;
-        };
-      };
-    };
-  };
-}
-```
+The NixOS module is in maintenance mode and will be removed once planterette is
+feature-complete. Full module documentation can be found [here](options.md).

all.sh

@@ -0,0 +1,3 @@
+#!/bin/sh -e
+
+HAKUREI_DIST_MAKE='' exec "$(dirname -- "$0")/cmd/dist/dist.sh"

check/absolute.go

@@ -0,0 +1,131 @@
+// Package check provides types yielding values checked to meet a condition.
+package check
+
+import (
+	"encoding"
+	"errors"
+	"fmt"
+	"path/filepath"
+	"slices"
+	"strings"
+	"syscall"
+	"unique"
+)
+
+// AbsoluteError is returned by [NewAbs] and holds the invalid pathname.
+type AbsoluteError string
+
+func (e AbsoluteError) Error() string {
+	return fmt.Sprintf("path %q is not absolute", string(e))
+}
+
+func (e AbsoluteError) Is(target error) bool {
+	var ce AbsoluteError
+	if !errors.As(target, &ce) {
+		return errors.Is(target, syscall.EINVAL)
+	}
+	return e == ce
+}
+
+// Absolute holds a pathname checked to be absolute.
+type Absolute struct{ pathname unique.Handle[string] }
+
+var (
+	_ encoding.TextAppender    = new(Absolute)
+	_ encoding.TextMarshaler   = new(Absolute)
+	_ encoding.TextUnmarshaler = new(Absolute)
+
+	_ encoding.BinaryAppender    = new(Absolute)
+	_ encoding.BinaryMarshaler   = new(Absolute)
+	_ encoding.BinaryUnmarshaler = new(Absolute)
+)
+
+// ok returns whether [Absolute] is not the zero value.
+func (a *Absolute) ok() bool { return a != nil && *a != (Absolute{}) }
+
+// unsafeAbs returns [check.Absolute] on any string value.
+func unsafeAbs(pathname string) *Absolute {
+	return &Absolute{unique.Make(pathname)}
+}
+
+// String returns the checked pathname.
+func (a *Absolute) String() string {
+	if !a.ok() {
+		panic("attempted use of zero Absolute")
+	}
+	return a.pathname.Value()
+}
+
+// Handle returns the underlying [unique.Handle].
+func (a *Absolute) Handle() unique.Handle[string] {
+	return a.pathname
+}
+
+// Is efficiently compares the underlying pathname.
+func (a *Absolute) Is(v *Absolute) bool {
+	if a == nil && v == nil {
+		return true
+	}
+	return a.ok() && v.ok() && a.pathname == v.pathname
+}
+
+// NewAbs checks pathname and returns a new [Absolute] if pathname is absolute.
+func NewAbs(pathname string) (*Absolute, error) {
+	if !filepath.IsAbs(pathname) {
+		return nil, AbsoluteError(pathname)
+	}
+	return unsafeAbs(pathname), nil
+}
+
+// MustAbs calls [NewAbs] and panics on error.
+func MustAbs(pathname string) *Absolute {
+	if a, err := NewAbs(pathname); err != nil {
+		panic(err)
+	} else {
+		return a
+	}
+}
+
+// Append calls [filepath.Join] with [Absolute] as the first element.
+func (a *Absolute) Append(elem ...string) *Absolute {
+	return unsafeAbs(filepath.Join(append([]string{a.String()}, elem...)...))
+}
+
+// Dir calls [filepath.Dir] with [Absolute] as its argument.
+func (a *Absolute) Dir() *Absolute { return unsafeAbs(filepath.Dir(a.String())) }
+
+// AppendText appends the checked pathname.
+func (a *Absolute) AppendText(data []byte) ([]byte, error) {
+	return append(data, a.String()...), nil
+}
+
+// MarshalText returns the checked pathname.
+func (a *Absolute) MarshalText() ([]byte, error) { return a.AppendText(nil) }
+
+// UnmarshalText stores data if it represents an absolute pathname.
+func (a *Absolute) UnmarshalText(data []byte) error {
+	pathname := string(data)
+	if !filepath.IsAbs(pathname) {
+		return AbsoluteError(pathname)
+	}
+	a.pathname = unique.Make(pathname)
+	return nil
+}
+
+func (a *Absolute) AppendBinary(data []byte) ([]byte, error) { return a.AppendText(data) }
+func (a *Absolute) MarshalBinary() ([]byte, error)           { return a.MarshalText() }
+func (a *Absolute) UnmarshalBinary(data []byte) error        { return a.UnmarshalText(data) }
+
+// SortAbs calls [slices.SortFunc] for a slice of [Absolute].
+func SortAbs(x []*Absolute) {
+	slices.SortFunc(x, func(a, b *Absolute) int {
+		return strings.Compare(a.String(), b.String())
+	})
+}
+
+// CompactAbs calls [slices.CompactFunc] for a slice of [Absolute].
+func CompactAbs(s []*Absolute) []*Absolute {
+	return slices.CompactFunc(s, func(a *Absolute, b *Absolute) bool {
+		return a.Is(b)
+	})
+}

check/absolute_test.go

@@ -0,0 +1,392 @@
+package check_test
+
+import (
+	"bytes"
+	"encoding/gob"
+	"encoding/json"
+	"errors"
+	"reflect"
+	"strings"
+	"syscall"
+	"testing"
+	_ "unsafe" // for go:linkname
+
+	. "hakurei.app/check"
+)
+
+// unsafeAbs returns check.Absolute on any string value.
+//
+//go:linkname unsafeAbs hakurei.app/check.unsafeAbs
+func unsafeAbs(pathname string) *Absolute
+
+func TestAbsoluteError(t *testing.T) {
+	t.Parallel()
+
+	testCases := []struct {
+		name string
+
+		err error
+		cmp error
+		ok  bool
+	}{
+		{"EINVAL", new(AbsoluteError), syscall.EINVAL, true},
+		{"not EINVAL", new(AbsoluteError), syscall.EBADE, false},
+		{"ne val", new(AbsoluteError), AbsoluteError("etc"), false},
+		{"equals", AbsoluteError("etc"), AbsoluteError("etc"), true},
+	}
+
+	for _, tc := range testCases {
+		if got := errors.Is(tc.err, tc.cmp); got != tc.ok {
+			t.Errorf("Is: %v, want %v", got, tc.ok)
+		}
+	}
+
+	t.Run("string", func(t *testing.T) {
+		t.Parallel()
+
+		want := `path "etc" is not absolute`
+		if got := (AbsoluteError("etc")).Error(); got != want {
+			t.Errorf("Error: %q, want %q", got, want)
+		}
+	})
+}
+
+func TestNewAbs(t *testing.T) {
+	t.Parallel()
+
+	testCases := []struct {
+		name string
+
+		pathname string
+		want     *Absolute
+		wantErr  error
+	}{
+		{"good", "/etc", MustAbs("/etc"), nil},
+		{"not absolute", "etc", nil, AbsoluteError("etc")},
+		{"zero", "", nil, AbsoluteError("")},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			t.Parallel()
+
+			got, err := NewAbs(tc.pathname)
+			if !reflect.DeepEqual(got, tc.want) {
+				t.Errorf("NewAbs: %#v, want %#v", got, tc.want)
+			}
+			if !errors.Is(err, tc.wantErr) {
+				t.Errorf("NewAbs: error = %v, want %v", err, tc.wantErr)
+			}
+		})
+	}
+
+	t.Run("must", func(t *testing.T) {
+		t.Parallel()
+
+		defer func() {
+			wantPanic := AbsoluteError("etc")
+
+			if r := recover(); !reflect.DeepEqual(r, wantPanic) {
+				t.Errorf("MustAbs: panic = %v; want %v", r, wantPanic)
+			}
+		}()
+
+		MustAbs("etc")
+	})
+}
+
+func TestAbsoluteString(t *testing.T) {
+	t.Run("passthrough", func(t *testing.T) {
+		t.Parallel()
+
+		pathname := "/etc"
+		if got := unsafeAbs(pathname).String(); got != pathname {
+			t.Errorf("String: %q, want %q", got, pathname)
+		}
+	})
+
+	t.Run("zero", func(t *testing.T) {
+		t.Parallel()
+
+		defer func() {
+			wantPanic := "attempted use of zero Absolute"
+
+			if r := recover(); r != wantPanic {
+				t.Errorf("String: panic = %v, want %v", r, wantPanic)
+			}
+		}()
+
+		panic(new(Absolute).String())
+	})
+}
+
+func TestAbsoluteIs(t *testing.T) {
+	t.Parallel()
+
+	testCases := []struct {
+		name string
+		a, v *Absolute
+		want bool
+	}{
+		{"nil", (*Absolute)(nil), (*Absolute)(nil), true},
+		{"nil a", (*Absolute)(nil), MustAbs("/"), false},
+		{"nil v", MustAbs("/"), (*Absolute)(nil), false},
+		{"zero", new(Absolute), new(Absolute), false},
+		{"zero a", new(Absolute), MustAbs("/"), false},
+		{"zero v", MustAbs("/"), new(Absolute), false},
+		{"equals", MustAbs("/"), MustAbs("/"), true},
+	}
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			t.Parallel()
+
+			if got := tc.a.Is(tc.v); got != tc.want {
+				t.Errorf("Is: %v, want %v", got, tc.want)
+			}
+		})
+	}
+}
+
+type sCheck struct {
+	Pathname *Absolute `json:"val"`
+	Magic    uint64    `json:"magic"`
+}
+
+func TestCodecAbsolute(t *testing.T) {
+	t.Parallel()
+
+	testCases := []struct {
+		name string
+		a    *Absolute
+
+		wantErr error
+
+		gob, sGob   string
+		json, sJson string
+	}{
+		{"nil", nil, nil,
+			"\x00", "\x00",
+			`null`, `{"val":null,"magic":3236757504}`},
+
+		{"good", MustAbs("/etc"),
+			nil,
+			"\t\x7f\x06\x01\x02\xff\x82\x00\x00\x00\b\xff\x80\x00\x04/etc",
+			",\xff\x83\x03\x01\x01\x06sCheck\x01\xff\x84\x00\x01\x02\x01\bPathname\x01\xff\x80\x00\x01\x05Magic\x01\x06\x00\x00\x00\t\x7f\x06\x01\x02\xff\x82\x00\x00\x00\x0f\xff\x84\x01\x04/etc\x01\xfc\xc0\xed\x00\x00\x00",
+
+			`"/etc"`, `{"val":"/etc","magic":3236757504}`},
+		{"not absolute", nil,
+			AbsoluteError("etc"),
+			"\t\x7f\x06\x01\x02\xff\x82\x00\x00\x00\a\xff\x80\x00\x03etc",
+			",\xff\x83\x03\x01\x01\x06sCheck\x01\xff\x84\x00\x01\x02\x01\bPathname\x01\xff\x80\x00\x01\x05Magic\x01\x06\x00\x00\x00\t\x7f\x06\x01\x02\xff\x82\x00\x00\x00\x0f\xff\x84\x01\x03etc\x01\xfb\x01\x81\xda\x00\x00\x00",
+
+			`"etc"`, `{"val":"etc","magic":3236757504}`},
+		{"zero", nil,
+			new(AbsoluteError),
+			"\t\x7f\x06\x01\x02\xff\x82\x00\x00\x00\x04\xff\x80\x00\x00",
+			",\xff\x83\x03\x01\x01\x06sCheck\x01\xff\x84\x00\x01\x02\x01\bPathname\x01\xff\x80\x00\x01\x05Magic\x01\x06\x00\x00\x00\t\x7f\x06\x01\x02\xff\x82\x00\x00\x00\f\xff\x84\x01\x00\x01\xfb\x01\x81\xda\x00\x00\x00",
+			`""`, `{"val":"","magic":3236757504}`},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			t.Parallel()
+
+			t.Run("gob", func(t *testing.T) {
+				if tc.gob == "\x00" && tc.sGob == "\x00" {
+					// these values mark the current test to skip gob
+					return
+				}
+				t.Parallel()
+
+				t.Run("encode", func(t *testing.T) {
+					t.Parallel()
+
+					// encode is unchecked
+					if errors.Is(tc.wantErr, syscall.EINVAL) {
+						return
+					}
+
+					{
+						buf := new(bytes.Buffer)
+						err := gob.NewEncoder(buf).Encode(tc.a)
+						if !errors.Is(err, tc.wantErr) {
+							t.Errorf("Encode: error = %v, want %v", err, tc.wantErr)
+						}
+						if tc.wantErr != nil {
+							goto checkSEncode
+						}
+						if buf.String() != tc.gob {
+							t.Errorf("Encode:\n%q\nwant:\n%q", buf.String(), tc.gob)
+						}
+					}
+
+				checkSEncode:
+					{
+						buf := new(bytes.Buffer)
+						err := gob.NewEncoder(buf).Encode(&sCheck{tc.a, syscall.MS_MGC_VAL})
+						if !errors.Is(err, tc.wantErr) {
+							t.Errorf("Encode: error = %v, want %v", err, tc.wantErr)
+						}
+						if tc.wantErr != nil {
+							return
+						}
+						if buf.String() != tc.sGob {
+							t.Errorf("Encode:\n%q\nwant:\n%q", buf.String(), tc.sGob)
+						}
+					}
+				})
+
+				t.Run("decode", func(t *testing.T) {
+					t.Parallel()
+
+					{
+						var gotA *Absolute
+						err := gob.NewDecoder(strings.NewReader(tc.gob)).Decode(&gotA)
+						if !errors.Is(err, tc.wantErr) {
+							t.Errorf("Decode: error = %v, want %v", err, tc.wantErr)
+						}
+						if tc.wantErr != nil {
+							goto checkSDecode
+						}
+						if !reflect.DeepEqual(tc.a, gotA) {
+							t.Errorf("Decode: %#v, want %#v", tc.a, gotA)
+						}
+					}
+
+				checkSDecode:
+					{
+						var gotSCheck sCheck
+						err := gob.NewDecoder(strings.NewReader(tc.sGob)).Decode(&gotSCheck)
+						if !errors.Is(err, tc.wantErr) {
+							t.Errorf("Decode: error = %v, want %v", err, tc.wantErr)
+						}
+						if tc.wantErr != nil {
+							return
+						}
+						want := sCheck{tc.a, syscall.MS_MGC_VAL}
+						if !reflect.DeepEqual(gotSCheck, want) {
+							t.Errorf("Decode: %#v, want %#v", gotSCheck, want)
+						}
+					}
+				})
+
+			})
+
+			t.Run("json", func(t *testing.T) {
+				t.Parallel()
+
+				t.Run("marshal", func(t *testing.T) {
+					t.Parallel()
+
+					// marshal is unchecked
+					if errors.Is(tc.wantErr, syscall.EINVAL) {
+						return
+					}
+
+					{
+						d, err := json.Marshal(tc.a)
+						if !errors.Is(err, tc.wantErr) {
+							t.Errorf("Marshal: error = %v, want %v", err, tc.wantErr)
+						}
+						if tc.wantErr != nil {
+							goto checkSMarshal
+						}
+						if string(d) != tc.json {
+							t.Errorf("Marshal:\n%s\nwant:\n%s", string(d), tc.json)
+						}
+					}
+
+				checkSMarshal:
+					{
+						d, err := json.Marshal(&sCheck{tc.a, syscall.MS_MGC_VAL})
+						if !errors.Is(err, tc.wantErr) {
+							t.Errorf("Marshal: error = %v, want %v", err, tc.wantErr)
+						}
+						if tc.wantErr != nil {
+							return
+						}
+						if string(d) != tc.sJson {
+							t.Errorf("Marshal:\n%s\nwant:\n%s", string(d), tc.sJson)
+						}
+					}
+				})
+
+				t.Run("unmarshal", func(t *testing.T) {
+					t.Parallel()
+
+					{
+						var gotA *Absolute
+						err := json.Unmarshal([]byte(tc.json), &gotA)
+						if !errors.Is(err, tc.wantErr) {
+							t.Errorf("Unmarshal: error = %v, want %v", err, tc.wantErr)
+						}
+						if tc.wantErr != nil {
+							goto checkSUnmarshal
+						}
+						if !reflect.DeepEqual(tc.a, gotA) {
+							t.Errorf("Unmarshal: %#v, want %#v", tc.a, gotA)
+						}
+					}
+
+				checkSUnmarshal:
+					{
+						var gotSCheck sCheck
+						err := json.Unmarshal([]byte(tc.sJson), &gotSCheck)
+						if !errors.Is(err, tc.wantErr) {
+							t.Errorf("Unmarshal: error = %v, want %v", err, tc.wantErr)
+						}
+						if tc.wantErr != nil {
+							return
+						}
+						want := sCheck{tc.a, syscall.MS_MGC_VAL}
+						if !reflect.DeepEqual(gotSCheck, want) {
+							t.Errorf("Unmarshal: %#v, want %#v", gotSCheck, want)
+						}
+					}
+				})
+			})
+		})
+	}
+}
+
+func TestAbsoluteWrap(t *testing.T) {
+	t.Parallel()
+
+	t.Run("join", func(t *testing.T) {
+		t.Parallel()
+
+		want := "/etc/nix/nix.conf"
+		if got := MustAbs("/etc").Append("nix", "nix.conf"); got.String() != want {
+			t.Errorf("Append: %q, want %q", got, want)
+		}
+	})
+
+	t.Run("dir", func(t *testing.T) {
+		t.Parallel()
+
+		want := "/"
+		if got := MustAbs("/etc").Dir(); got.String() != want {
+			t.Errorf("Dir: %q, want %q", got, want)
+		}
+	})
+
+	t.Run("sort", func(t *testing.T) {
+		t.Parallel()
+
+		want := []*Absolute{MustAbs("/etc"), MustAbs("/proc"), MustAbs("/sys")}
+		got := []*Absolute{MustAbs("/proc"), MustAbs("/sys"), MustAbs("/etc")}
+		SortAbs(got)
+		if !reflect.DeepEqual(got, want) {
+			t.Errorf("SortAbs: %#v, want %#v", got, want)
+		}
+	})
+
+	t.Run("compact", func(t *testing.T) {
+		t.Parallel()
+
+		want := []*Absolute{MustAbs("/etc"), MustAbs("/proc"), MustAbs("/sys")}
+		if got := CompactAbs([]*Absolute{MustAbs("/etc"), MustAbs("/proc"), MustAbs("/proc"), MustAbs("/sys")}); !reflect.DeepEqual(got, want) {
+			t.Errorf("CompactAbs: %#v, want %#v", got, want)
+		}
+	})
+}

check/overlay.go

@@ -0,0 +1,38 @@
+package check
+
+import "strings"
+
+const (
+	// SpecialOverlayEscape is the escape string for overlay mount options.
+	//
+	// Deprecated: This is no longer used and will be removed in 0.5.
+	SpecialOverlayEscape = `\`
+	// SpecialOverlayOption is the separator string between overlay mount options.
+	//
+	// Deprecated: This is no longer used and will be removed in 0.5.
+	SpecialOverlayOption = ","
+	// SpecialOverlayPath is the separator string between overlay paths.
+	//
+	// Deprecated: This is no longer used and will be removed in 0.5.
+	SpecialOverlayPath = ":"
+)
+
+// EscapeOverlayDataSegment escapes a string for formatting into the data
+// argument of an overlay mount system call.
+//
+// Deprecated: This is no longer used and will be removed in 0.5.
+func EscapeOverlayDataSegment(s string) string {
+	if s == "" {
+		return ""
+	}
+
+	if f := strings.SplitN(s, "\x00", 2); len(f) > 0 {
+		s = f[0]
+	}
+
+	return strings.NewReplacer(
+		SpecialOverlayEscape, SpecialOverlayEscape+SpecialOverlayEscape,
+		SpecialOverlayOption, SpecialOverlayEscape+SpecialOverlayOption,
+		SpecialOverlayPath, SpecialOverlayEscape+SpecialOverlayPath,
+	).Replace(s)
+}

check/overlay_test.go

@@ -0,0 +1,31 @@
+package check_test
+
+import (
+	"testing"
+
+	"hakurei.app/check"
+)
+
+func TestEscapeOverlayDataSegment(t *testing.T) {
+	t.Parallel()
+
+	testCases := []struct {
+		name string
+		s    string
+		want string
+	}{
+		{"zero", "", ""},
+		{"multi", `\\\:,:,\\\`, `\\\\\\\:\,\:\,\\\\\\`},
+		{"bwrap", `/path :,\`, `/path \:\,\\`},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			t.Parallel()
+
+			if got := check.EscapeOverlayDataSegment(tc.s); got != tc.want {
+				t.Errorf("escapeOverlayDataSegment: %s, want %s", got, tc.want)
+			}
+		})
+	}
+}

cmd/dist/comp/_hakurei

@@ -1,21 +1,24 @@
 #compdef hakurei
 
-_hakurei_app() {
+_hakurei_run() {
   __hakurei_files
   return $?
 }
 
-_hakurei_run() {
+_hakurei_exec() {
   _arguments \
     '--id[Reverse-DNS style Application identifier, leave empty to inherit instance identifier]:id' \
     '-a[Application identity]: :_numbers' \
     '-g[Groups inherited by all container processes]: :_groups' \
     '-d[Container home directory]: :_files -/' \
     '-u[Passwd user name within sandbox]: :_users' \
+    '--private-runtime[Do not share XDG_RUNTIME_DIR between containers under the same identity]' \
+    '--private-tmpdir[Do not share TMPDIR between containers under the same identity]' \
     '--wayland[Enable connection to Wayland via security-context-v1]' \
     '-X[Enable direct connection to X11]' \
     '--dbus[Enable proxied connection to D-Bus]' \
-    '--pulse[Enable direct connection to PulseAudio]' \
+    '--pipewire[Enable connection to PipeWire via SecurityContext]' \
+    '--pulse[Enable PulseAudio compatibility daemon]' \
     '--dbus-config[Path to session bus proxy config file]: :_files -g "*.json"' \
     '--dbus-system[Path to system bus proxy config file]: :_files -g "*.json"' \
     '--mpris[Allow owning MPRIS D-Bus path]' \
@@ -54,9 +57,9 @@ __hakurei_instances() {
 {
   local -a _hakurei_cmds
   _hakurei_cmds=(
-    "app:Load app from configuration file"
-    "run:Configure and start a permissive default sandbox"
-    "show:Show live or local app configuration"
+    "run:Load and start container from configuration file"
+    "exec:Configure and start a permissive container"
+    "show:Show live or local instance configuration"
     "ps:List active instances"
     "version:Display version information"
     "license:Show full license text"

cmd/dist/dist.sh

@@ -0,0 +1,10 @@
+#!/bin/sh -e
+
+TOOLCHAIN_VERSION="$(go version)"
+cd "$(dirname -- "$0")/../.."
+echo "Building cmd/dist using ${TOOLCHAIN_VERSION}."
+FLAGS=''
+if test -n "$VERBOSE"; then
+    FLAGS="$FLAGS -v"
+fi
+go run $FLAGS --tags=dist ./cmd/dist

cmd/dist/main.go

@@ -0,0 +1,249 @@
+//go:build dist
+
+package main
+
+import (
+	"archive/tar"
+	"compress/gzip"
+	"context"
+	"crypto/sha512"
+	_ "embed"
+	"encoding/hex"
+	"fmt"
+	"io"
+	"io/fs"
+	"log"
+	"os"
+	"os/exec"
+	"os/signal"
+	"path/filepath"
+	"runtime"
+)
+
+// getenv looks up an environment variable, and returns fallback if it is unset.
+func getenv(key, fallback string) string {
+	if v, ok := os.LookupEnv(key); ok {
+		return v
+	}
+	return fallback
+}
+
+// mustRun runs a command with the current process's environment and panics
+// on error or non-zero exit code.
+func mustRun(ctx context.Context, name string, arg ...string) {
+	cmd := exec.CommandContext(ctx, name, arg...)
+	cmd.Stdin, cmd.Stdout, cmd.Stderr = os.Stdin, os.Stdout, os.Stderr
+	if err := cmd.Run(); err != nil {
+		panic(err)
+	}
+}
+
+//go:embed comp/_hakurei
+var comp []byte
+
+func main() {
+	log.SetFlags(0)
+	log.SetPrefix("")
+
+	verbose := os.Getenv("VERBOSE") != ""
+	runTests := os.Getenv("HAKUREI_DIST_MAKE") == ""
+	version := getenv("HAKUREI_VERSION", "untagged")
+	prefix := getenv("PREFIX", "/usr")
+	destdir := getenv("DESTDIR", "dist")
+
+	if verbose {
+		log.Println()
+	}
+
+	if err := os.MkdirAll(destdir, 0755); err != nil {
+		log.Fatal(err)
+	}
+	s, err := os.MkdirTemp(destdir, ".dist.*")
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer func() {
+		var code int
+
+		if err = os.RemoveAll(s); err != nil {
+			code = 1
+			log.Println(err)
+		}
+
+		if r := recover(); r != nil {
+			code = 1
+			log.Println(r)
+		}
+
+		os.Exit(code)
+	}()
+
+	ctx, cancel := signal.NotifyContext(context.Background(), os.Interrupt)
+	defer cancel()
+
+	verboseFlag := "-v"
+	if !verbose {
+		verboseFlag = "-buildvcs=false"
+	}
+
+	log.Printf("Building hakurei for %s/%s.", runtime.GOOS, runtime.GOARCH)
+	mustRun(ctx, "go", "generate", "./...")
+	mustRun(
+		ctx, "go", "build",
+		"-trimpath",
+		verboseFlag, "-o", s,
+		"-ldflags=-s -w "+
+			"-buildid= -linkmode external -extldflags=-static "+
+			"-X hakurei.app/internal/info.buildVersion="+version+" "+
+			"-X hakurei.app/internal/info.hakureiPath="+prefix+"/bin/hakurei "+
+			"-X hakurei.app/internal/info.hsuPath="+prefix+"/bin/hsu "+
+			"-X main.hakureiPath="+prefix+"/bin/hakurei",
+		"./...",
+	)
+	log.Println()
+
+	if runTests {
+		log.Println("##### Testing Hakurei.")
+		mustRun(
+			ctx, "go", "test",
+			"-ldflags=-buildid= -linkmode external -extldflags=-static",
+			"./...",
+		)
+		log.Println()
+	}
+
+	log.Println("##### Creating distribution.")
+	const suffix = ".tar.gz"
+	distName := "hakurei-" + version + "-" + runtime.GOARCH
+	var f *os.File
+	if f, err = os.OpenFile(
+		filepath.Join(s, distName+suffix),
+		os.O_CREATE|os.O_EXCL|os.O_WRONLY,
+		0644,
+	); err != nil {
+		panic(err)
+	}
+	defer func() {
+		if f == nil {
+			return
+		}
+		if err = f.Close(); err != nil {
+			log.Println(err)
+		}
+	}()
+
+	h := sha512.New()
+	gw, _ := gzip.NewWriterLevel(io.MultiWriter(f, h), gzip.BestCompression)
+	tw := tar.NewWriter(gw)
+
+	mustWriteHeader := func(name string, size int64, mode os.FileMode) {
+		header := tar.Header{
+			Name:  filepath.Join(distName, name),
+			Size:  size,
+			Mode:  int64(mode),
+			Uname: "root",
+			Gname: "root",
+		}
+
+		if mode&os.ModeDir != 0 {
+			header.Typeflag = tar.TypeDir
+			fmt.Printf("%s %s\n", mode, name)
+		} else {
+			header.Typeflag = tar.TypeReg
+			fmt.Printf("%s %s (%d bytes)\n", mode, name, size)
+		}
+
+		if err = tw.WriteHeader(&header); err != nil {
+			panic(err)
+		}
+	}
+
+	mustWriteFile := func(name string, data []byte, mode os.FileMode) {
+		mustWriteHeader(name, int64(len(data)), mode)
+		if mode&os.ModeDir != 0 {
+			return
+		}
+		if _, err = tw.Write(data); err != nil {
+			panic(err)
+		}
+	}
+
+	mustWriteFromPath := func(dst, src string, mode os.FileMode) {
+		var r *os.File
+		if r, err = os.Open(src); err != nil {
+			panic(err)
+		}
+
+		var fi os.FileInfo
+		if fi, err = r.Stat(); err != nil {
+			_ = r.Close()
+			panic(err)
+		}
+
+		if mode == 0 {
+			mode = fi.Mode()
+		}
+
+		mustWriteHeader(dst, fi.Size(), mode)
+		if _, err = io.Copy(tw, r); err != nil {
+			_ = r.Close()
+			panic(err)
+		} else if err = r.Close(); err != nil {
+			panic(err)
+		}
+	}
+
+	mustWriteFile(".", nil, fs.ModeDir|0755)
+	mustWriteFile("comp/", nil, os.ModeDir|0755)
+	mustWriteFile("comp/_hakurei", comp, 0644)
+	mustWriteFile("install.sh", []byte(`#!/bin/sh -e
+cd "$(dirname -- "$0")" || exit 1
+
+install -vDm0755 "bin/hakurei" "${DESTDIR}`+prefix+`/bin/hakurei"
+install -vDm0755 "bin/sharefs" "${DESTDIR}`+prefix+`/bin/sharefs"
+
+install -vDm4511 "bin/hsu" "${DESTDIR}`+prefix+`/bin/hsu"
+if [ ! -f "${DESTDIR}/etc/hsurc" ]; then
+    install -vDm0400 "hsurc.default" "${DESTDIR}/etc/hsurc"
+fi
+
+install -vDm0644 "comp/_hakurei" "${DESTDIR}`+prefix+`/share/zsh/site-functions/_hakurei"
+`), 0755)
+
+	mustWriteFromPath("README.md", "README.md", 0)
+	mustWriteFile("hsurc.default", []byte("1000 0"), 0400)
+	mustWriteFromPath("bin/hsu", filepath.Join(s, "hsu"), 04511)
+	for _, name := range []string{
+		"hakurei",
+		"sharefs",
+	} {
+		mustWriteFromPath(
+			filepath.Join("bin", name),
+			filepath.Join(s, name),
+			0,
+		)
+	}
+
+	if err = tw.Close(); err != nil {
+		panic(err)
+	} else if err = gw.Close(); err != nil {
+		panic(err)
+	} else if err = f.Close(); err != nil {
+		panic(err)
+	}
+	f = nil
+
+	if err = os.WriteFile(
+		filepath.Join(destdir, distName+suffix+".sha512"),
+		append(hex.AppendEncode(nil, h.Sum(nil)), "  "+distName+suffix+"\n"...),
+		0644,
+	); err != nil {
+		panic(err)
+	}
+	if err = os.Rename(
+		filepath.Join(s, distName+suffix),
+		filepath.Join(destdir, distName+suffix),
+	); err != nil {
+		panic(err)
+	}
+}

cmd/earlyinit/main.go

@@ -0,0 +1,131 @@
+// The earlyinit is part of the Rosa OS initramfs and serves as the system init.
+//
+// This program is an internal detail of Rosa OS and is not usable on its own.
+// It is not covered by the compatibility promise.
+package main
+
+import (
+	"log"
+	"os"
+	"runtime"
+	"strings"
+	. "syscall"
+)
+
+func main() {
+	runtime.LockOSThread()
+	log.SetFlags(0)
+	log.SetPrefix("earlyinit: ")
+
+	var (
+		option map[string]string
+		flags  []string
+	)
+	if len(os.Args) > 1 {
+		option = make(map[string]string)
+		for _, s := range os.Args[1:] {
+			key, value, ok := strings.Cut(s, "=")
+			if !ok {
+				flags = append(flags, s)
+				continue
+			}
+			option[key] = value
+		}
+	}
+
+	if err := Mount(
+		"devtmpfs",
+		"/dev/",
+		"devtmpfs",
+		MS_NOSUID|MS_NOEXEC,
+		"",
+	); err != nil {
+		log.Fatalf("cannot mount devtmpfs: %v", err)
+	}
+
+	// The kernel might be unable to set up the console. When that happens,
+	// printk is called with "Warning: unable to open an initial console."
+	// and the init runs with no files. The checkfds runtime function
+	// populates 0-2 by opening /dev/null for them.
+	//
+	// This check replaces 1 and 2 with /dev/kmsg to improve the chance
+	// of output being visible to the user.
+	if fi, err := os.Stdout.Stat(); err == nil {
+		if stat, ok := fi.Sys().(*Stat_t); ok {
+			if stat.Rdev == 0x103 {
+				var fd int
+				if fd, err = Open(
+					"/dev/kmsg",
+					O_WRONLY|O_CLOEXEC,
+					0,
+				); err != nil {
+					log.Fatalf("cannot open kmsg: %v", err)
+				}
+
+				if err = Dup3(fd, Stdout, 0); err != nil {
+					log.Fatalf("cannot open stdout: %v", err)
+				}
+				if err = Dup3(fd, Stderr, 0); err != nil {
+					log.Fatalf("cannot open stderr: %v", err)
+				}
+
+				if err = Close(fd); err != nil {
+					log.Printf("cannot close kmsg: %v", err)
+				}
+			}
+		}
+	}
+
+	// staying in rootfs, these are no longer used
+	must(os.Remove("/root"))
+	must(os.Remove("/init"))
+
+	must(os.Mkdir("/proc", 0))
+	mustSyscall("mount proc", Mount(
+		"proc",
+		"/proc",
+		"proc",
+		MS_NOSUID|MS_NOEXEC|MS_NODEV,
+		"hidepid=1",
+	))
+
+	must(os.Mkdir("/sys", 0))
+	mustSyscall("mount sysfs", Mount(
+		"sysfs",
+		"/sys",
+		"sysfs",
+		0,
+		"",
+	))
+
+	// after top level has been set up
+	mustSyscall("remount root", Mount(
+		"",
+		"/",
+		"",
+		MS_REMOUNT|MS_BIND|
+			MS_RDONLY|MS_NODEV|MS_NOSUID|MS_NOEXEC,
+		"",
+	))
+
+	must(os.WriteFile(
+		"/sys/module/firmware_class/parameters/path",
+		[]byte("/system/lib/firmware"),
+		0,
+	))
+
+}
+
+// mustSyscall calls [log.Fatalln] if err is non-nil.
+func mustSyscall(action string, err error) {
+	if err != nil {
+		log.Fatalln("cannot "+action+":", err)
+	}
+}
+
+// must calls [log.Fatal] with err if it is non-nil.
+func must(err error) {
+	if err != nil {
+		log.Fatal(err)
+	}
+}

cmd/hakurei/command.go

@@ -2,76 +2,117 @@ package main
 
 import (
 	"context"
+	"errors"
 	"fmt"
 	"io"
 	"log"
 	"os"
-	"os/signal"
+	"os/exec"
 	"os/user"
 	"strconv"
 	"sync"
-	"syscall"
 	"time"
 
+	"hakurei.app/check"
 	"hakurei.app/command"
+	"hakurei.app/ext"
+	"hakurei.app/fhs"
 	"hakurei.app/hst"
-	"hakurei.app/internal"
-	"hakurei.app/internal/app"
-	"hakurei.app/internal/app/state"
-	"hakurei.app/internal/hlog"
-	"hakurei.app/system"
-	"hakurei.app/system/dbus"
+	"hakurei.app/internal/dbus"
+	"hakurei.app/internal/env"
+	"hakurei.app/internal/info"
+	"hakurei.app/internal/outcome"
+	"hakurei.app/message"
 )
 
-func buildCommand(out io.Writer) command.Command {
+// optionalErrorUnwrap calls [errors.Unwrap] and returns the resulting value
+// if it is not nil, or the original value if it is.
+func optionalErrorUnwrap(err error) error {
+	if underlyingErr := errors.Unwrap(err); underlyingErr != nil {
+		return underlyingErr
+	}
+	return err
+}
+
+var errSuccess = errors.New("success")
+
+func buildCommand(ctx context.Context, msg message.Msg, early *earlyHardeningErrs, out io.Writer) command.Command {
 	var (
-		flagVerbose bool
-		flagJSON    bool
+		flagVerbose  bool
+		flagInsecure bool
+		flagJSON     bool
 	)
-	c := command.New(out, log.Printf, "hakurei", func([]string) error { internal.InstallOutput(flagVerbose); return nil }).
-		Flag(&flagVerbose, "v", command.BoolFlag(false), "Increase log verbosity").
-		Flag(&flagJSON, "json", command.BoolFlag(false), "Serialise output in JSON when applicable")
+	c := command.New(out, log.Printf, "hakurei", func([]string) error {
+		msg.SwapVerbose(flagVerbose)
 
-	c.Command("shim", command.UsageInternal, func([]string) error { app.ShimMain(); return errSuccess })
-
-	c.Command("app", "Load app from configuration file", func(args []string) error {
-		if len(args) < 1 {
-			log.Fatal("app requires at least 1 argument")
+		if early.yamaLSM != nil {
+			msg.Verbosef("cannot enable ptrace protection via Yama LSM: %v", early.yamaLSM)
+			// not fatal
 		}
 
-		// config extraArgs...
-		config := tryPath(args[0])
-		config.Args = append(config.Args, args[1:]...)
+		if early.dumpable != nil {
+			log.Printf("cannot set SUID_DUMP_DISABLE: %s", early.dumpable)
+			// not fatal
+		}
 
-		runApp(config)
-		panic("unreachable")
-	})
+		return nil
+	}).
+		Flag(&flagVerbose, "v", command.BoolFlag(false), "Increase log verbosity").
+		Flag(&flagInsecure, "insecure", command.BoolFlag(false), "Allow use of insecure compatibility options").
+		Flag(&flagJSON, "json", command.BoolFlag(false), "Serialise output in JSON when applicable")
+
+	c.Command("shim", command.UsageInternal, func([]string) error { outcome.Shim(msg); return errSuccess })
 
 	{
 		var (
-			dbusConfigSession string
-			dbusConfigSystem  string
-			mpris             bool
-			dbusVerbose       bool
-
-			fid      string
-			aid      int
-			groups   command.RepeatableFlag
-			homeDir  string
-			userName string
-
-			wayland, x11, dBus, pulse bool
+			flagIdentifierFile int
 		)
-
-		c.NewCommand("run", "Configure and start a permissive default sandbox", func(args []string) error {
-			// initialise config from flags
-			config := &hst.Config{
-				ID:   fid,
-				Args: args,
+		c.NewCommand("run", "Load and start container from configuration file", func(args []string) error {
+			if len(args) < 1 {
+				log.Fatal("run requires at least 1 argument")
 			}
 
-			if aid < 0 || aid > 9999 {
-				log.Fatalf("aid %d out of range", aid)
+			config := tryPath(msg, args[0])
+			if config != nil && config.Container != nil {
+				config.Container.Args = append(config.Container.Args, args[1:]...)
+			}
+
+			var flags int
+			if flagInsecure {
+				flags |= hst.VAllowInsecure
+			}
+
+			outcome.Main(ctx, msg, config, flags, flagIdentifierFile)
+			panic("unreachable")
+		}).
+			Flag(&flagIdentifierFile, "identifier-fd", command.IntFlag(-1),
+				"Write identifier of current instance to fd after successful startup")
+	}
+
+	{
+		var (
+			flagDBusConfigSession string
+			flagDBusConfigSystem  string
+			flagDBusMpris         bool
+			flagDBusVerbose       bool
+
+			flagID       string
+			flagIdentity int
+			flagGroups   command.RepeatableFlag
+			flagHomeDir  string
+			flagUserName string
+
+			flagSchedPolicy   string
+			flagSchedPriority int
+
+			flagPrivateRuntime, flagPrivateTmpdir bool
+
+			flagWayland, flagX11, flagDBus, flagPipeWire, flagPulse bool
+		)
+
+		c.NewCommand("exec", "Configure and start a permissive container", func(args []string) error {
+			if flagIdentity < hst.IdentityStart || flagIdentity > hst.IdentityEnd {
+				log.Fatalf("identity %d out of range", flagIdentity)
 			}
 
 			// resolve home/username from os when flag is unset
@@ -79,22 +120,15 @@ func buildCommand(out io.Writer) command.Command {
 				passwd     *user.User
 				passwdOnce sync.Once
 				passwdFunc = func() {
-					var us string
-					if uid, err := std.Uid(aid); err != nil {
-						hlog.PrintBaseError(err, "cannot obtain uid from setuid wrapper:")
-						os.Exit(1)
-					} else {
-						us = strconv.Itoa(uid)
-					}
-
+					us := strconv.Itoa(hst.ToUser(new(outcome.Hsu).MustID(msg), flagIdentity))
 					if u, err := user.LookupId(us); err != nil {
-						hlog.Verbosef("cannot look up uid %s", us)
+						msg.Verbosef("cannot look up uid %s", us)
 						passwd = &user.User{
 							Uid:      us,
 							Gid:      us,
 							Username: "chronos",
 							Name:     "Hakurei Permissive Default",
-							HomeDir:  "/var/empty",
+							HomeDir:  fhs.VarEmpty,
 						}
 					} else {
 						passwd = u
@@ -102,156 +136,256 @@ func buildCommand(out io.Writer) command.Command {
 				}
 			)
 
-			if homeDir == "os" {
+			// paths are identical, resolve inner shell and program path
+			shell := fhs.AbsRoot.Append("bin", "sh")
+			if a, err := check.NewAbs(os.Getenv("SHELL")); err == nil {
+				shell = a
+			}
+			progPath := shell
+			if len(args) > 0 {
+				if p, err := exec.LookPath(args[0]); err != nil {
+					log.Fatal(optionalErrorUnwrap(err))
+					return err
+				} else if progPath, err = check.NewAbs(p); err != nil {
+					log.Fatal(err)
+					return err
+				}
+			}
+
+			var et hst.Enablements
+			if flagWayland {
+				et |= hst.EWayland
+			}
+			if flagX11 {
+				et |= hst.EX11
+			}
+			if flagDBus {
+				et |= hst.EDBus
+			}
+			if flagPipeWire || flagPulse {
+				et |= hst.EPipeWire
+			}
+
+			config := hst.Config{
+				ID:          flagID,
+				Identity:    flagIdentity,
+				Groups:      flagGroups,
+				Enablements: &et,
+
+				Container: &hst.ContainerConfig{
+					Filesystem: []hst.FilesystemConfigJSON{
+						// autoroot, includes the home directory
+						{FilesystemConfig: &hst.FSBind{
+							Target:  fhs.AbsRoot,
+							Source:  fhs.AbsRoot,
+							Write:   true,
+							Special: true,
+						}},
+					},
+
+					Username: flagUserName,
+					Shell:    shell,
+
+					Path: progPath,
+					Args: args,
+
+					Flags: hst.FUserns | hst.FHostNet | hst.FHostAbstract | hst.FTty,
+				},
+			}
+
+			if err := config.SchedPolicy.UnmarshalText(
+				[]byte(flagSchedPolicy),
+			); err != nil {
+				log.Fatal(err)
+			}
+			config.SchedPriority = ext.Int(flagSchedPriority)
+
+			// bind GPU stuff
+			if et&(hst.EX11|hst.EWayland) != 0 {
+				config.Container.Filesystem = append(config.Container.Filesystem, hst.FilesystemConfigJSON{FilesystemConfig: &hst.FSBind{
+					Source:   fhs.AbsDev.Append("dri"),
+					Device:   true,
+					Optional: true,
+				}})
+			}
+
+			config.Container.Filesystem = append(config.Container.Filesystem,
+				// opportunistically bind kvm
+				hst.FilesystemConfigJSON{FilesystemConfig: &hst.FSBind{
+					Source:   fhs.AbsDev.Append("kvm"),
+					Device:   true,
+					Optional: true,
+				}},
+
+				// do autoetc last
+				hst.FilesystemConfigJSON{FilesystemConfig: &hst.FSBind{
+					Target:  fhs.AbsEtc,
+					Source:  fhs.AbsEtc,
+					Special: true,
+				}},
+			)
+
+			if config.Container.Username == "chronos" {
 				passwdOnce.Do(passwdFunc)
-				homeDir = passwd.HomeDir
+				config.Container.Username = passwd.Username
 			}
 
-			if userName == "chronos" {
-				passwdOnce.Do(passwdFunc)
-				userName = passwd.Username
+			{
+				homeDir := flagHomeDir
+				if homeDir == "os" {
+					passwdOnce.Do(passwdFunc)
+					homeDir = passwd.HomeDir
+				}
+				if a, err := check.NewAbs(homeDir); err != nil {
+					log.Fatal(err)
+					return err
+				} else {
+					config.Container.Home = a
+				}
 			}
 
-			config.Identity = aid
-			config.Groups = groups
-			config.Data = homeDir
-			config.Username = userName
-
-			if wayland {
-				config.Enablements |= system.EWayland
+			if !flagPrivateRuntime {
+				config.Container.Flags |= hst.FShareRuntime
 			}
-			if x11 {
-				config.Enablements |= system.EX11
-			}
-			if dBus {
-				config.Enablements |= system.EDBus
-			}
-			if pulse {
-				config.Enablements |= system.EPulse
+			if !flagPrivateTmpdir {
+				config.Container.Flags |= hst.FShareTmpdir
 			}
 
 			// parse D-Bus config file from flags if applicable
-			if dBus {
-				if dbusConfigSession == "builtin" {
-					config.SessionBus = dbus.NewConfig(fid, true, mpris)
+			if flagDBus {
+				if flagDBusConfigSession == "builtin" {
+					config.SessionBus = dbus.NewConfig(flagID, true, flagDBusMpris)
 				} else {
-					if conf, err := dbus.NewConfigFromFile(dbusConfigSession); err != nil {
-						log.Fatalf("cannot load session bus proxy config from %q: %s", dbusConfigSession, err)
+					if f, err := os.Open(flagDBusConfigSession); err != nil {
+						log.Fatal(err)
 					} else {
-						config.SessionBus = conf
+						decodeJSON(log.Fatal, "load session bus proxy config", f, &config.SessionBus)
+						if err = f.Close(); err != nil {
+							log.Fatal(err)
+						}
 					}
 				}
 
 				// system bus proxy is optional
-				if dbusConfigSystem != "nil" {
-					if conf, err := dbus.NewConfigFromFile(dbusConfigSystem); err != nil {
-						log.Fatalf("cannot load system bus proxy config from %q: %s", dbusConfigSystem, err)
+				if flagDBusConfigSystem != "nil" {
+					if f, err := os.Open(flagDBusConfigSystem); err != nil {
+						log.Fatal(err)
 					} else {
-						config.SystemBus = conf
+						decodeJSON(log.Fatal, "load system bus proxy config", f, &config.SystemBus)
+						if err = f.Close(); err != nil {
+							log.Fatal(err)
+						}
 					}
 				}
 
 				// override log from configuration
-				if dbusVerbose {
-					config.SessionBus.Log = true
-					config.SystemBus.Log = true
+				if flagDBusVerbose {
+					if config.SessionBus != nil {
+						config.SessionBus.Log = true
+					}
+					if config.SystemBus != nil {
+						config.SystemBus.Log = true
+					}
 				}
 			}
 
-			// invoke app
-			runApp(config)
+			outcome.Main(ctx, msg, &config, 0, -1)
 			panic("unreachable")
 		}).
-			Flag(&dbusConfigSession, "dbus-config", command.StringFlag("builtin"),
+			Flag(&flagDBusConfigSession, "dbus-config", command.StringFlag("builtin"),
 				"Path to session bus proxy config file, or \"builtin\" for defaults").
-			Flag(&dbusConfigSystem, "dbus-system", command.StringFlag("nil"),
+			Flag(&flagDBusConfigSystem, "dbus-system", command.StringFlag("nil"),
 				"Path to system bus proxy config file, or \"nil\" to disable").
-			Flag(&mpris, "mpris", command.BoolFlag(false),
+			Flag(&flagDBusMpris, "mpris", command.BoolFlag(false),
 				"Allow owning MPRIS D-Bus path, has no effect if custom config is available").
-			Flag(&dbusVerbose, "dbus-log", command.BoolFlag(false),
+			Flag(&flagDBusVerbose, "dbus-log", command.BoolFlag(false),
 				"Force buffered logging in the D-Bus proxy").
-			Flag(&fid, "id", command.StringFlag(""),
+			Flag(&flagID, "id", command.StringFlag(""),
 				"Reverse-DNS style Application identifier, leave empty to inherit instance identifier").
-			Flag(&aid, "a", command.IntFlag(0),
+			Flag(&flagIdentity, "a", command.IntFlag(0),
 				"Application identity").
-			Flag(nil, "g", &groups,
+			Flag(nil, "g", &flagGroups,
 				"Groups inherited by all container processes").
-			Flag(&homeDir, "d", command.StringFlag("os"),
+			Flag(&flagHomeDir, "d", command.StringFlag("os"),
 				"Container home directory").
-			Flag(&userName, "u", command.StringFlag("chronos"),
+			Flag(&flagUserName, "u", command.StringFlag("chronos"),
 				"Passwd user name within sandbox").
-			Flag(&wayland, "wayland", command.BoolFlag(false),
+			Flag(&flagSchedPolicy, "policy", command.StringFlag(""),
+				"Scheduling policy to set for the container").
+			Flag(&flagSchedPriority, "priority", command.IntFlag(0),
+				"Scheduling priority to set for the container").
+			Flag(&flagPrivateRuntime, "private-runtime", command.BoolFlag(false),
+				"Do not share XDG_RUNTIME_DIR between containers under the same identity").
+			Flag(&flagPrivateTmpdir, "private-tmpdir", command.BoolFlag(false),
+				"Do not share TMPDIR between containers under the same identity").
+			Flag(&flagWayland, "wayland", command.BoolFlag(false),
 				"Enable connection to Wayland via security-context-v1").
-			Flag(&x11, "X", command.BoolFlag(false),
+			Flag(&flagX11, "X", command.BoolFlag(false),
 				"Enable direct connection to X11").
-			Flag(&dBus, "dbus", command.BoolFlag(false),
+			Flag(&flagDBus, "dbus", command.BoolFlag(false),
 				"Enable proxied connection to D-Bus").
-			Flag(&pulse, "pulse", command.BoolFlag(false),
-				"Enable direct connection to PulseAudio")
+			Flag(&flagPipeWire, "pipewire", command.BoolFlag(false),
+				"Enable connection to PipeWire via SecurityContext").
+			Flag(&flagPulse, "pulse", command.BoolFlag(false),
+				"Enable PulseAudio compatibility daemon")
 	}
 
-	var showFlagShort bool
-	c.NewCommand("show", "Show live or local app configuration", func(args []string) error {
-		switch len(args) {
-		case 0: // system
-			printShowSystem(os.Stdout, showFlagShort, flagJSON)
+	{
+		var (
+			flagShort   bool
+			flagNoStore bool
+		)
+		c.NewCommand("show", "Show live or local instance configuration", func(args []string) error {
+			switch len(args) {
+			case 0: // system
+				printShowSystem(os.Stdout, flagShort, flagJSON)
 
-		case 1: // instance
-			name := args[0]
-			config, entry := tryShort(name)
-			if config == nil {
-				config = tryPath(name)
+			case 1: // instance
+				name := args[0]
+
+				var (
+					config *hst.Config
+					entry  *hst.State
+				)
+				if !flagNoStore {
+					var sc hst.Paths
+					env.CopyPaths().Copy(&sc, new(outcome.Hsu).MustID(nil))
+					entry = tryIdentifier(msg, name, outcome.NewStore(&sc))
+				}
+
+				if entry == nil {
+					config = tryPath(msg, name)
+				} else {
+					config = entry.Config
+				}
+
+				if !printShowInstance(os.Stdout, time.Now().UTC(), entry, config, flagShort, flagJSON) {
+					os.Exit(1)
+				}
+
+			default:
+				log.Fatal("show requires 1 argument")
 			}
-			printShowInstance(os.Stdout, time.Now().UTC(), entry, config, showFlagShort, flagJSON)
+			return errSuccess
+		}).
+			Flag(&flagShort, "short", command.BoolFlag(false), "Omit filesystem information").
+			Flag(&flagNoStore, "no-store", command.BoolFlag(false), "Do not attempt to match from active instances")
+	}
 
-		default:
-			log.Fatal("show requires 1 argument")
-		}
-		return errSuccess
-	}).Flag(&showFlagShort, "short", command.BoolFlag(false), "Omit filesystem information")
+	{
+		var flagShort bool
+		c.NewCommand("ps", "List active instances", func(args []string) error {
+			var sc hst.Paths
+			env.CopyPaths().Copy(&sc, new(outcome.Hsu).MustID(nil))
+			printPs(msg, os.Stdout, time.Now().UTC(), outcome.NewStore(&sc), flagShort, flagJSON)
+			return errSuccess
+		}).Flag(&flagShort, "short", command.BoolFlag(false), "Print instance id")
+	}
 
-	var psFlagShort bool
-	c.NewCommand("ps", "List active instances", func(args []string) error {
-		printPs(os.Stdout, time.Now().UTC(), state.NewMulti(std.Paths().RunDirPath), psFlagShort, flagJSON)
-		return errSuccess
-	}).Flag(&psFlagShort, "short", command.BoolFlag(false), "Print instance id")
-
-	c.Command("version", "Display version information", func(args []string) error {
-		fmt.Println(internal.Version())
-		return errSuccess
-	})
-
-	c.Command("license", "Show full license text", func(args []string) error {
-		fmt.Println(license)
-		return errSuccess
-	})
-
-	c.Command("template", "Produce a config template", func(args []string) error {
-		printJSON(os.Stdout, false, hst.Template())
-		return errSuccess
-	})
-
-	c.Command("help", "Show this help message", func([]string) error {
-		c.PrintHelp()
-		return errSuccess
-	})
+	c.Command("version", "Display version information", func(args []string) error { fmt.Println(info.Version()); return errSuccess })
+	c.Command("license", "Show full license text", func(args []string) error { fmt.Println(license); return errSuccess })
+	c.Command("template", "Produce a config template", func(args []string) error { encodeJSON(log.Fatal, os.Stdout, false, hst.Template()); return errSuccess })
+	c.Command("help", "Show this help message", func([]string) error { c.PrintHelp(); return errSuccess })
 
 	return c
 }
-
-func runApp(config *hst.Config) {
-	ctx, stop := signal.NotifyContext(context.Background(),
-		syscall.SIGINT, syscall.SIGTERM)
-	defer stop() // unreachable
-	a := app.MustNew(ctx, std)
-
-	rs := new(app.RunState)
-	if sa, err := a.Seal(config); err != nil {
-		hlog.PrintBaseError(err, "cannot seal app:")
-		internal.Exit(1)
-	} else {
-		internal.Exit(app.PrintRunStateErr(rs, sa.Run(rs)))
-	}
-
-	*(*int)(nil) = 0 // not reached
-}

cmd/hakurei/command_test.go

@@ -7,9 +7,12 @@ import (
 	"testing"
 
 	"hakurei.app/command"
+	"hakurei.app/message"
 )
 
 func TestHelp(t *testing.T) {
+	t.Parallel()
+
 	testCases := []struct {
 		name string
 		args []string
@@ -17,12 +20,12 @@ func TestHelp(t *testing.T) {
 	}{
 		{
 			"main", []string{}, `
-Usage:	hakurei [-h | --help] [-v] [--json] COMMAND [OPTIONS]
+Usage:	hakurei [-h | --help] [-v] [--insecure] [--json] COMMAND [OPTIONS]
 
 Commands:
-    app         Load app from configuration file
-    run         Configure and start a permissive default sandbox
-    show        Show live or local app configuration
+    run         Load and start container from configuration file
+    exec        Configure and start a permissive container
+    show        Show live or local instance configuration
     ps          List active instances
     version     Display version information
     license     Show full license text
@@ -32,8 +35,8 @@ Commands:
 `,
 		},
 		{
-			"run", []string{"run", "-h"}, `
-Usage:	hakurei run [-h | --help] [--dbus-config <value>] [--dbus-system <value>] [--mpris] [--dbus-log] [--id <value>] [-a <int>] [-g <value>] [-d <value>] [-u <value>] [--wayland] [-X] [--dbus] [--pulse] COMMAND [OPTIONS]
+			"exec", []string{"exec", "-h"}, `
+Usage:	hakurei exec [-h | --help] [--dbus-config <value>] [--dbus-system <value>] [--mpris] [--dbus-log] [--id <value>] [-a <int>] [-g <value>] [-d <value>] [-u <value>] [--policy <value>] [--priority <int>] [--private-runtime] [--private-tmpdir] [--wayland] [-X] [--dbus] [--pipewire] [--pulse] COMMAND [OPTIONS]
 
 Flags:
   -X	Enable direct connection to X11
@@ -55,8 +58,18 @@ Flags:
     	Reverse-DNS style Application identifier, leave empty to inherit instance identifier
   -mpris
     	Allow owning MPRIS D-Bus path, has no effect if custom config is available
+  -pipewire
+    	Enable connection to PipeWire via SecurityContext
+  -policy string
+    	Scheduling policy to set for the container
+  -priority int
+    	Scheduling priority to set for the container
+  -private-runtime
+    	Do not share XDG_RUNTIME_DIR between containers under the same identity
+  -private-tmpdir
+    	Do not share TMPDIR between containers under the same identity
   -pulse
-    	Enable direct connection to PulseAudio
+    	Enable PulseAudio compatibility daemon
   -u string
     	Passwd user name within sandbox (default "chronos")
   -wayland
@@ -67,8 +80,10 @@ Flags:
 	}
 	for _, tc := range testCases {
 		t.Run(tc.name, func(t *testing.T) {
+			t.Parallel()
+
 			out := new(bytes.Buffer)
-			c := buildCommand(out)
+			c := buildCommand(t.Context(), message.New(nil), new(earlyHardeningErrs), out)
 			if err := c.Parse(tc.args); !errors.Is(err, command.ErrHelp) && !errors.Is(err, flag.ErrHelp) {
 				t.Errorf("Parse: error = %v; want %v",
 					err, command.ErrHelp)

cmd/hakurei/json.go

@@ -0,0 +1,60 @@
+package main
+
+import (
+	"encoding/json"
+	"errors"
+	"io"
+	"strconv"
+)
+
+// decodeJSON decodes json from r and stores it in v. A non-nil error results in a call to fatal.
+func decodeJSON(fatal func(v ...any), op string, r io.Reader, v any) {
+	err := json.NewDecoder(r).Decode(v)
+	if err == nil {
+		return
+	}
+
+	var (
+		syntaxError        *json.SyntaxError
+		unmarshalTypeError *json.UnmarshalTypeError
+
+		msg string
+	)
+
+	switch {
+	case errors.As(err, &syntaxError) && syntaxError != nil:
+		msg = syntaxError.Error() +
+			" at byte " + strconv.FormatInt(syntaxError.Offset, 10)
+
+	case errors.As(err, &unmarshalTypeError) && unmarshalTypeError != nil:
+		msg = "inappropriate " + unmarshalTypeError.Value +
+			" at byte " + strconv.FormatInt(unmarshalTypeError.Offset, 10)
+
+	default:
+		// InvalidUnmarshalError: incorrect usage, does not need to be handled
+		// io.ErrUnexpectedEOF: no additional error information available
+		msg = err.Error()
+	}
+
+	fatal("cannot " + op + ": " + msg)
+}
+
+// encodeJSON encodes v to output. A non-nil error results in a call to fatal.
+func encodeJSON(fatal func(v ...any), output io.Writer, short bool, v any) {
+	encoder := json.NewEncoder(output)
+	if !short {
+		encoder.SetIndent("", "  ")
+	}
+
+	if err := encoder.Encode(v); err != nil {
+		var marshalerError *json.MarshalerError
+		if errors.As(err, &marshalerError) && marshalerError != nil {
+			// this likely indicates an implementation error in hst
+			fatal("cannot encode json for " + marshalerError.Type.String() + ": " + marshalerError.Err.Error())
+			return
+		}
+
+		// UnsupportedTypeError, UnsupportedValueError: incorrect usage, does not need to be handled
+		fatal("cannot write json: " + err.Error())
+	}
+}

cmd/hakurei/json_test.go

@@ -0,0 +1,99 @@
+package main
+
+import (
+	"reflect"
+	"strings"
+	"testing"
+
+	"hakurei.app/internal/stub"
+)
+
+func TestDecodeJSON(t *testing.T) {
+	t.Parallel()
+
+	testCases := []struct {
+		name string
+		t    reflect.Type
+		data string
+		want any
+		msg  string
+	}{
+		{"success", reflect.TypeFor[uintptr](), "3735928559\n", uintptr(0xdeadbeef), ""},
+
+		{"syntax", reflect.TypeFor[*int](), "\x00", nil,
+			`cannot load sample: invalid character '\x00' looking for beginning of value at byte 1`},
+		{"type", reflect.TypeFor[uintptr](), "-1", nil,
+			`cannot load sample: inappropriate number -1 at byte 2`},
+		{"default", reflect.TypeFor[*int](), "{", nil,
+			"cannot load sample: unexpected EOF"},
+	}
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			t.Parallel()
+
+			var (
+				gotP   = reflect.New(tc.t)
+				gotMsg *string
+			)
+			decodeJSON(func(v ...any) {
+				if gotMsg != nil {
+					t.Fatal("fatal called twice")
+				}
+				msg := v[0].(string)
+				gotMsg = &msg
+			}, "load sample", strings.NewReader(tc.data), gotP.Interface())
+			if tc.msg != "" {
+				if gotMsg == nil {
+					t.Errorf("decodeJSON: success, want fatal %q", tc.msg)
+				} else if *gotMsg != tc.msg {
+					t.Errorf("decodeJSON: fatal = %q, want %q", *gotMsg, tc.msg)
+				}
+			} else if gotMsg != nil {
+				t.Errorf("decodeJSON: fatal = %q", *gotMsg)
+			} else if !reflect.DeepEqual(gotP.Elem().Interface(), tc.want) {
+				t.Errorf("decodeJSON: %#v, want %#v", gotP.Elem().Interface(), tc.want)
+			}
+		})
+	}
+}
+
+func TestEncodeJSON(t *testing.T) {
+	t.Parallel()
+
+	testCases := []struct {
+		name string
+		v    any
+		want string
+	}{
+		{"marshaler", errorJSONMarshaler{},
+			`cannot encode json for main.errorJSONMarshaler: unique error 3735928559 injected by the test suite`},
+		{"default", func() {},
+			`cannot write json: json: unsupported type: func()`},
+	}
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			t.Parallel()
+
+			var called bool
+			encodeJSON(func(v ...any) {
+				if called {
+					t.Fatal("fatal called twice")
+				}
+				called = true
+
+				if v[0].(string) != tc.want {
+					t.Errorf("encodeJSON: fatal = %q, want %q", v[0].(string), tc.want)
+				}
+			}, nil, false, tc.v)
+
+			if !called {
+				t.Errorf("encodeJSON: success, want fatal %q", tc.want)
+			}
+		})
+	}
+}
+
+// errorJSONMarshaler implements json.Marshaler.
+type errorJSONMarshaler struct{}
+
+func (errorJSONMarshaler) MarshalJSON() ([]byte, error) { return nil, stub.UniqueError(0xdeadbeef) }

cmd/hakurei/main.go

@@ -1,48 +1,88 @@
+// Hakurei runs user-specified containers as subordinate users.
+//
+// This program is generally invoked by another, higher level program, which
+// creates container configuration via package [hst] or an implementation of it.
+//
+// The parent may leave files open and specify their file descriptor for various
+// uses. In these cases, standard streams and netpoll files are treated as
+// invalid file descriptors and rejected. All string representations must be in
+// decimal.
+//
+// When specifying a [hst.Config] JSON stream or file to the run subcommand, the
+// argument "-" is equivalent to stdin. Otherwise, file descriptor rules
+// described above applies. Invalid file descriptors are treated as file names
+// in their string representation, with the exception that if a netpoll file
+// descriptor is attempted, the program fails.
+//
+// The flag --identifier-fd can be optionally specified to the run subcommand to
+// receive the identifier of the newly started instance. File descriptor rules
+// described above applies, and the file must be writable. This is sent after
+// its state is made available, so the client must not attempt to poll for it.
+// This uses the internal binary format of [hst.ID].
+//
+// For the show and ps subcommands, the flag --json can be applied to the main
+// hakurei command to serialise output in JSON when applicable. Additionally,
+// the flag --short targeting each subcommand is used to omit some information
+// in both JSON and user-facing output. Only JSON-encoded output is covered
+// under the compatibility promise.
+//
+// A template for [hst.Config] demonstrating all available configuration fields
+// is returned by [hst.Template]. The JSON-encoded equivalent of this can be
+// obtained via the template subcommand. Fields left unpopulated in the template
+// (the direct_* family of fields, which are insecure under any configuration if
+// enabled) are unsupported.
+//
+// For simple (but insecure) testing scenarios, the exec subcommand can be used
+// to generate a simple, permissive configuration in-memory. See its help
+// message for all available options.
 package main
 
-// this works around go:embed '..' limitation
-//go:generate cp ../../LICENSE .
-
 import (
+	"context"
 	_ "embed"
 	"errors"
 	"log"
 	"os"
+	"os/signal"
+	"syscall"
 
 	"hakurei.app/container"
-	"hakurei.app/internal"
-	"hakurei.app/internal/hlog"
-	"hakurei.app/internal/sys"
+	"hakurei.app/ext"
+	"hakurei.app/message"
 )
 
-var (
-	errSuccess = errors.New("success")
+//go:generate cp ../../LICENSE .
+//go:embed LICENSE
+var license string
 
-	//go:embed LICENSE
-	license string
-)
-
-func init() { hlog.Prepare("hakurei") }
-
-var std sys.State = new(sys.Std)
+// earlyHardeningErrs are errors collected while setting up early hardening feature.
+type earlyHardeningErrs struct{ yamaLSM, dumpable error }
 
 func main() {
 	// early init path, skips root check and duplicate PR_SET_DUMPABLE
-	container.TryArgv0(hlog.Output{}, hlog.Prepare, internal.InstallOutput)
+	container.TryArgv0(nil)
 
-	if err := container.SetDumpable(container.SUID_DUMP_DISABLE); err != nil {
-		log.Printf("cannot set SUID_DUMP_DISABLE: %s", err)
-		// not fatal: this program runs as the privileged user
+	log.SetFlags(0)
+	log.SetPrefix("hakurei: ")
+	msg := message.New(log.Default())
+
+	early := earlyHardeningErrs{
+		yamaLSM:  ext.SetPtracer(0),
+		dumpable: ext.SetDumpable(ext.SUID_DUMP_DISABLE),
 	}
 
 	if os.Geteuid() == 0 {
 		log.Fatal("this program must not run as root")
 	}
 
-	buildCommand(os.Stderr).MustParse(os.Args[1:], func(err error) {
-		hlog.Verbosef("command returned %v", err)
+	ctx, stop := signal.NotifyContext(context.Background(),
+		syscall.SIGINT, syscall.SIGTERM)
+	defer stop() // unreachable
+
+	buildCommand(ctx, msg, &early, os.Stderr).MustParse(os.Args[1:], func(err error) {
+		msg.Verbosef("command returned %v", err)
 		if errors.Is(err, errSuccess) {
-			hlog.BeforeExit()
+			msg.BeforeExit()
 			os.Exit(0)
 		}
 		// this catches faulty command handlers that fail to return before this point

cmd/hakurei/parse.go

@@ -1,7 +1,7 @@
 package main
 
 import (
-	"encoding/json"
+	"encoding/hex"
 	"errors"
 	"io"
 	"log"
@@ -11,66 +11,104 @@ import (
 	"syscall"
 
 	"hakurei.app/hst"
-	"hakurei.app/internal/app/state"
-	"hakurei.app/internal/hlog"
+	"hakurei.app/internal/outcome"
+	"hakurei.app/internal/store"
+	"hakurei.app/message"
 )
 
-func tryPath(name string) (config *hst.Config) {
-	var r io.Reader
+// tryPath attempts to read [hst.Config] from multiple sources.
+//
+// tryPath reads from [os.Stdin] if name has value "-". Otherwise, name is
+// passed to tryFd, and if that returns nil, name is passed to [os.Open].
+func tryPath(msg message.Msg, name string) (config *hst.Config) {
+	var r io.ReadCloser
 	config = new(hst.Config)
 
 	if name != "-" {
-		r = tryFd(name)
+		r = tryFd(msg, name)
 		if r == nil {
-			hlog.Verbose("load configuration from file")
+			msg.Verbose("load configuration from file")
 
 			if f, err := os.Open(name); err != nil {
-				log.Fatalf("cannot access configuration file %q: %s", name, err)
+				log.Fatal(err.Error())
+				return
 			} else {
-				// finalizer closes f
 				r = f
 			}
-		} else {
-			defer func() {
-				if err := r.(io.ReadCloser).Close(); err != nil {
-					log.Printf("cannot close config fd: %v", err)
-				}
-			}()
 		}
 	} else {
 		r = os.Stdin
 	}
 
-	if err := json.NewDecoder(r).Decode(&config); err != nil {
-		log.Fatalf("cannot load configuration: %v", err)
+	decodeJSON(log.Fatal, "load configuration", r, &config)
+	if err := r.Close(); err != nil {
+		log.Fatal(err.Error())
 	}
-
 	return
 }
 
-func tryFd(name string) io.ReadCloser {
+// tryFd returns a [io.ReadCloser] if name represents an integer corresponding
+// to a valid file descriptor.
+func tryFd(msg message.Msg, name string) io.ReadCloser {
 	if v, err := strconv.Atoi(name); err != nil {
 		if !errors.Is(err, strconv.ErrSyntax) {
-			hlog.Verbosef("name cannot be interpreted as int64: %v", err)
+			msg.Verbosef("name cannot be interpreted as int64: %v", err)
 		}
 		return nil
 	} else {
-		hlog.Verbosef("trying config stream from %d", v)
+		if v < 3 { // reject standard streams
+			return nil
+		}
+
+		msg.Verbosef("trying config stream from %d", v)
 		fd := uintptr(v)
-		if _, _, errno := syscall.Syscall(syscall.SYS_FCNTL, fd, syscall.F_GETFD, 0); errno != 0 {
-			if errors.Is(errno, syscall.EBADF) {
+		if _, _, errno := syscall.Syscall(
+			syscall.SYS_FCNTL,
+			fd,
+			syscall.F_GETFD,
+			0,
+		); errno != 0 {
+			if errors.Is(errno, syscall.EBADF) { // reject bad fd
 				return nil
 			}
 			log.Fatalf("cannot get fd %d: %v", fd, errno)
 		}
+
+		if outcome.IsPollDescriptor(fd) { // reject runtime internals
+			log.Fatalf("invalid config stream %d", fd)
+		}
+
 		return os.NewFile(fd, strconv.Itoa(v))
 	}
 }
 
-func tryShort(name string) (config *hst.Config, entry *state.State) {
-	likePrefix := false
-	if len(name) <= 32 {
-		likePrefix = true
+// shortLengthMin is the minimum length a short form identifier can have and
+// still be interpreted as an identifier.
+const shortLengthMin = 1 << 3
+
+// shortIdentifier returns an eight character short representation of [hst.ID]
+// from its random bytes.
+func shortIdentifier(id *hst.ID) string {
+	return shortIdentifierString(id.String())
+}
+
+// shortIdentifierString implements shortIdentifier on an arbitrary string.
+func shortIdentifierString(s string) string {
+	return s[len(hst.ID{}) : len(hst.ID{})+shortLengthMin]
+}
+
+// tryIdentifier attempts to match [hst.State] from a [hex] representation of
+// [hst.ID] or a prefix of its lower half.
+func tryIdentifier(msg message.Msg, name string, s *store.Store) *hst.State {
+	const (
+		likeShort = 1 << iota
+		likeFull
+	)
+
+	var likely uintptr
+	// half the hex representation
+	if len(name) >= shortLengthMin && len(name) <= len(hst.ID{}) {
+		// cannot safely decode here due to unknown alignment
 		for _, c := range name {
 			if c >= '0' && c <= '9' {
 				continue
@@ -78,33 +116,68 @@ func tryShort(name string) (config *hst.Config, entry *state.State) {
 			if c >= 'a' && c <= 'f' {
 				continue
 			}
-			likePrefix = false
-			break
+			return nil
 		}
+		likely |= likeShort
+	} else if len(name) == hex.EncodedLen(len(hst.ID{})) {
+		likely |= likeFull
 	}
 
-	// try to match from state store
-	if likePrefix && len(name) >= 8 {
-		hlog.Verbose("argument looks like prefix")
+	if likely == 0 {
+		return nil
+	}
 
-		s := state.NewMulti(std.Paths().RunDirPath)
-		if entries, err := state.Join(s); err != nil {
-			log.Printf("cannot join store: %v", err)
-			// drop to fetch from file
-		} else {
-			for id := range entries {
-				v := id.String()
-				if strings.HasPrefix(v, name) {
-					// match, use config from this state entry
-					entry = entries[id]
-					config = entry.Config
-					break
+	entries, copyError := s.All()
+	defer func() {
+		if err := copyError(); err != nil {
+			msg.GetLogger().Println(getMessage("cannot iterate over store:", err))
+		}
+	}()
+
+	switch {
+	case likely&likeShort != 0:
+		msg.Verbose("argument looks like short identifier")
+		for eh := range entries {
+			if eh.DecodeErr != nil {
+				msg.Verbose(getMessage("skipping instance:", eh.DecodeErr))
+				continue
+			}
+
+			if strings.HasPrefix(eh.ID.String()[len(hst.ID{}):], name) {
+				var entry hst.State
+				if _, err := eh.Load(&entry); err != nil {
+					msg.GetLogger().Println(getMessage("cannot load state entry:", err))
+					continue
 				}
-
-				hlog.Verbosef("instance %s skipped", v)
+				return &entry
 			}
 		}
-	}
+		return nil
 
-	return
+	case likely&likeFull != 0:
+		var likelyID hst.ID
+		if likelyID.UnmarshalText([]byte(name)) != nil {
+			return nil
+		}
+		msg.Verbose("argument looks like identifier")
+		for eh := range entries {
+			if eh.DecodeErr != nil {
+				msg.Verbose(getMessage("skipping instance:", eh.DecodeErr))
+				continue
+			}
+
+			if eh.ID == likelyID {
+				var entry hst.State
+				if _, err := eh.Load(&entry); err != nil {
+					msg.GetLogger().Println(getMessage("cannot load state entry:", err))
+					continue
+				}
+				return &entry
+			}
+		}
+		return nil
+
+	default:
+		panic("unreachable")
+	}
 }

cmd/hakurei/parse_test.go

@@ -0,0 +1,117 @@
+package main
+
+import (
+	"bytes"
+	"reflect"
+	"testing"
+	"time"
+
+	"hakurei.app/check"
+	"hakurei.app/hst"
+	"hakurei.app/internal/store"
+	"hakurei.app/message"
+)
+
+func TestShortIdentifier(t *testing.T) {
+	t.Parallel()
+	id := hst.ID{
+		0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef,
+		0xfe, 0xdc, 0xba, 0x98, 0x76, 0x54, 0x32, 0x10,
+	}
+
+	const want = "fedcba98"
+	if got := shortIdentifier(&id); got != want {
+		t.Errorf("shortIdentifier: %q, want %q", got, want)
+	}
+}
+
+func TestTryIdentifier(t *testing.T) {
+	t.Parallel()
+
+	msg := message.New(nil)
+	id := hst.ID{
+		0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef,
+		0xfe, 0xdc, 0xba, 0x98, 0x76, 0x54, 0x32, 0x10,
+	}
+	withBase := func(extra ...hst.State) []hst.State {
+		return append([]hst.State{
+			{ID: (hst.ID)(bytes.Repeat([]byte{0xaa}, len(hst.ID{}))), PID: 0xbeef, ShimPID: 0xcafe, Config: hst.Template(), Time: time.Unix(0, 0xdeadbeef0)},
+			{ID: (hst.ID)(bytes.Repeat([]byte{0xab}, len(hst.ID{}))), PID: 0x1beef, ShimPID: 0x1cafe, Config: hst.Template(), Time: time.Unix(0, 0xdeadbeef1)},
+			{ID: (hst.ID)(bytes.Repeat([]byte{0xf0}, len(hst.ID{}))), PID: 0x2beef, ShimPID: 0x2cafe, Config: hst.Template(), Time: time.Unix(0, 0xdeadbeef2)},
+
+			{ID: (hst.ID)(bytes.Repeat([]byte{0xfe}, len(hst.ID{}))), PID: 0xbed, ShimPID: 0xfff, Config: func() *hst.Config {
+				template := hst.Template()
+				template.Identity = hst.IdentityEnd
+				return template
+			}(), Time: time.Unix(0, 0xcafebabe0)},
+			{ID: (hst.ID)(bytes.Repeat([]byte{0xfc}, len(hst.ID{}))), PID: 0x1bed, ShimPID: 0x1fff, Config: func() *hst.Config {
+				template := hst.Template()
+				template.Identity = 0xfc
+				return template
+			}(), Time: time.Unix(0, 0xcafebabe1)},
+			{ID: (hst.ID)(bytes.Repeat([]byte{0xce}, len(hst.ID{}))), PID: 0x2bed, ShimPID: 0x2fff, Config: func() *hst.Config {
+				template := hst.Template()
+				template.Identity = 0xce
+				return template
+			}(), Time: time.Unix(0, 0xcafebabe2)},
+		}, extra...)
+	}
+	sampleEntry := hst.State{
+		ID:      id,
+		PID:     0xcafe,
+		ShimPID: 0xdead,
+		Config:  hst.Template(),
+	}
+
+	testCases := []struct {
+		name string
+		s    string
+		data []hst.State
+		want *hst.State
+	}{
+		{"likely entries fault", "ffffffff", nil, nil},
+
+		{"likely short too short", "ff", nil, nil},
+		{"likely short too long", "fffffffffffffffff", nil, nil},
+		{"likely short invalid lower", "fffffff\x00", nil, nil},
+		{"likely short invalid higher", "0000000\xff", nil, nil},
+		{"short no match", "fedcba98", withBase(), nil},
+		{"short match", "fedcba98", withBase(sampleEntry), &sampleEntry},
+		{"short match single", "fedcba98", []hst.State{sampleEntry}, &sampleEntry},
+		{"short match longer", "fedcba98765", withBase(sampleEntry), &sampleEntry},
+
+		{"likely long invalid", "0123456789abcdeffedcba987654321\x00", nil, nil},
+		{"long no match", "0123456789abcdeffedcba9876543210", withBase(), nil},
+		{"long match", "0123456789abcdeffedcba9876543210", withBase(sampleEntry), &sampleEntry},
+		{"long match single", "0123456789abcdeffedcba9876543210", []hst.State{sampleEntry}, &sampleEntry},
+	}
+	for _, tc := range testCases {
+		base := check.MustAbs(t.TempDir()).Append("store")
+		s := store.New(base)
+		for i := range tc.data {
+			if h, err := s.Handle(tc.data[i].Identity); err != nil {
+				t.Fatalf("Handle: error = %v", err)
+			} else {
+				var unlock func()
+				if unlock, err = h.Lock(); err != nil {
+					t.Fatalf("Lock: error = %v", err)
+				}
+				_, err = h.Save(&tc.data[i])
+				unlock()
+				if err != nil {
+					t.Fatalf("Save: error = %v", err)
+				}
+			}
+		}
+
+		// store must not be written to beyond this point
+		t.Run(tc.name, func(t *testing.T) {
+			t.Parallel()
+
+			got := tryIdentifier(msg, tc.s, store.New(base))
+			if !reflect.DeepEqual(got, tc.want) {
+				t.Errorf("tryIdentifier: %#v, want %#v", got, tc.want)
+			}
+		})
+	}
+}

cmd/hakurei/print.go

@@ -1,11 +1,10 @@
 package main
 
 import (
-	"encoding/json"
+	"bytes"
 	"fmt"
 	"io"
 	"log"
-	"os"
 	"slices"
 	"strconv"
 	"strings"
@@ -13,42 +12,43 @@ import (
 	"time"
 
 	"hakurei.app/hst"
-	"hakurei.app/internal/app/state"
-	"hakurei.app/internal/hlog"
-	"hakurei.app/system/dbus"
+	"hakurei.app/internal/outcome"
+	"hakurei.app/internal/store"
+	"hakurei.app/message"
 )
 
+// printShowSystem populates and writes a representation of [hst.Info] to output.
 func printShowSystem(output io.Writer, short, flagJSON bool) {
 	t := newPrinter(output)
 	defer t.MustFlush()
-
-	info := new(hst.Info)
-
-	// get fid by querying uid of aid 0
-	if uid, err := std.Uid(0); err != nil {
-		hlog.PrintBaseError(err, "cannot obtain uid from setuid wrapper:")
-		os.Exit(1)
-	} else {
-		info.User = (uid / 10000) - 100
-	}
+	hi := outcome.Info()
 
 	if flagJSON {
-		printJSON(output, short, info)
+		encodeJSON(log.Fatal, output, short, hi)
 		return
 	}
 
-	t.Printf("User:\t%d\n", info.User)
+	t.Printf("Version:\t%s (libwayland %s)\n", hi.Version, hi.WaylandVersion)
+	t.Printf("User:\t%d\n", hi.User)
+	t.Printf("TempDir:\t%s\n", hi.TempDir)
+	t.Printf("SharePath:\t%s\n", hi.SharePath)
+	t.Printf("RuntimePath:\t%s\n", hi.RuntimePath)
+	t.Printf("RunDirPath:\t%s\n", hi.RunDirPath)
 }
 
+// printShowInstance writes a representation of [hst.State] or [hst.Config] to output.
 func printShowInstance(
 	output io.Writer, now time.Time,
-	instance *state.State, config *hst.Config,
-	short, flagJSON bool) {
+	instance *hst.State, config *hst.Config,
+	short, flagJSON bool,
+) (valid bool) {
+	valid = true
+
 	if flagJSON {
 		if instance != nil {
-			printJSON(output, short, instance)
+			encodeJSON(log.Fatal, output, short, instance)
 		} else {
-			printJSON(output, short, config)
+			encodeJSON(log.Fatal, output, short, config)
 		}
 		return
 	}
@@ -56,13 +56,21 @@ func printShowInstance(
 	t := newPrinter(output)
 	defer t.MustFlush()
 
-	if config.Container == nil {
-		mustPrint(output, "Warning: this configuration uses permissive defaults!\n\n")
+	if err := config.Validate(hst.VAllowInsecure); err != nil {
+		valid = false
+		if m, ok := message.GetMessage(err); ok {
+			mustPrint(output, "Error: "+m+"!\n\n")
+		}
+	}
+
+	if config == nil {
+		// nothing to print
+		return
 	}
 
 	if instance != nil {
 		t.Printf("State\n")
-		t.Printf(" Instance:\t%s (%d)\n", instance.ID.String(), instance.PID)
+		t.Printf(" Instance:\t%s (%d -> %d)\n", instance.ID.String(), instance.PID, instance.ShimPID)
 		t.Printf(" Uptime:\t%s\n", now.Sub(instance.Time).Round(time.Second).String())
 		t.Printf("\n")
 	}
@@ -73,51 +81,37 @@ func printShowInstance(
 	} else {
 		t.Printf(" Identity:\t%d\n", config.Identity)
 	}
-	t.Printf(" Enablements:\t%s\n", config.Enablements.String())
+	t.Printf(" Enablements:\t%s\n", config.Enablements.Unwrap().String())
 	if len(config.Groups) > 0 {
 		t.Printf(" Groups:\t%s\n", strings.Join(config.Groups, ", "))
 	}
-	if config.Data != "" {
-		t.Printf(" Data:\t%s\n", config.Data)
-	}
 	if config.Container != nil {
-		container := config.Container
-		if container.Hostname != "" {
-			t.Printf(" Hostname:\t%s\n", container.Hostname)
-		}
-		flags := make([]string, 0, 7)
-		writeFlag := func(name string, value bool) {
-			if value {
-				flags = append(flags, name)
+		flags := config.Container.Flags.String()
+
+		// this is included in the upper hst.Config struct but is relevant here
+		const flagDirectWayland = "directwl"
+		if config.DirectWayland {
+			// hardcoded value when every flag is unset
+			if flags == "none" {
+				flags = flagDirectWayland
+			} else {
+				flags += ", " + flagDirectWayland
 			}
 		}
-		writeFlag("userns", container.Userns)
-		writeFlag("devel", container.Devel)
-		writeFlag("net", container.Net)
-		writeFlag("device", container.Device)
-		writeFlag("tty", container.Tty)
-		writeFlag("mapuid", container.MapRealUID)
-		writeFlag("directwl", config.DirectWayland)
-		writeFlag("autoetc", container.AutoEtc)
-		if len(flags) == 0 {
-			flags = append(flags, "none")
-		}
-		t.Printf(" Flags:\t%s\n", strings.Join(flags, " "))
+		t.Printf(" Flags:\t%s\n", flags)
 
-		etc := container.Etc
-		if etc == "" {
-			etc = "/etc"
+		if config.Container.Home != nil {
+			t.Printf(" Home:\t%s\n", config.Container.Home)
 		}
-		t.Printf(" Etc:\t%s\n", etc)
-
-		if len(container.Cover) > 0 {
-			t.Printf(" Cover:\t%s\n", strings.Join(container.Cover, " "))
+		if config.Container.Hostname != "" {
+			t.Printf(" Hostname:\t%s\n", config.Container.Hostname)
+		}
+		if config.Container.Path != nil {
+			t.Printf(" Path:\t%s\n", config.Container.Path)
+		}
+		if len(config.Container.Args) > 0 {
+			t.Printf(" Arguments:\t%s\n", strings.Join(config.Container.Args, " "))
 		}
-
-		t.Printf(" Path:\t%s\n", config.Path)
-	}
-	if len(config.Args) > 0 {
-		t.Printf(" Arguments:\t%s\n", strings.Join(config.Args, " "))
 	}
 	t.Printf("\n")
 
@@ -125,46 +119,25 @@ func printShowInstance(
 		if config.Container != nil && len(config.Container.Filesystem) > 0 {
 			t.Printf("Filesystem\n")
 			for _, f := range config.Container.Filesystem {
-				if f == nil {
+				if !f.Valid() {
+					valid = false
+					t.Println(" <invalid>")
 					continue
 				}
-
-				expr := new(strings.Builder)
-				expr.Grow(3 + len(f.Src) + 1 + len(f.Dst))
-
-				if f.Device {
-					expr.WriteString(" d")
-				} else if f.Write {
-					expr.WriteString(" w")
-				} else {
-					expr.WriteString(" ")
-				}
-				if f.Must {
-					expr.WriteString("*")
-				} else {
-					expr.WriteString("+")
-				}
-				expr.WriteString(f.Src)
-				if f.Dst != "" {
-					expr.WriteString(":" + f.Dst)
-				}
-				t.Printf("%s\n", expr.String())
+				t.Printf(" %s\n", f)
 			}
 			t.Printf("\n")
 		}
 		if len(config.ExtraPerms) > 0 {
 			t.Printf("Extra ACL\n")
-			for _, p := range config.ExtraPerms {
-				if p == nil {
-					continue
-				}
-				t.Printf(" %s\n", p.String())
+			for i := range config.ExtraPerms {
+				t.Printf(" %s\n", config.ExtraPerms[i].String())
 			}
 			t.Printf("\n")
 		}
 	}
 
-	printDBus := func(c *dbus.Config) {
+	printDBus := func(c *hst.BusConfig) {
 		t.Printf(" Filter:\t%v\n", c.Filter)
 		if len(c.See) > 0 {
 			t.Printf(" See:\t%q\n", c.See)
@@ -192,59 +165,57 @@ func printShowInstance(
 		printDBus(config.SystemBus)
 		t.Printf("\n")
 	}
+
+	return
 }
 
-func printPs(output io.Writer, now time.Time, s state.Store, short, flagJSON bool) {
-	var entries state.Entries
-	if e, err := state.Join(s); err != nil {
-		log.Fatalf("cannot join store: %v", err)
-	} else {
-		entries = e
-	}
-	if err := s.Close(); err != nil {
-		log.Printf("cannot close store: %v", err)
+// printPs writes a representation of active instances to output.
+func printPs(msg message.Msg, output io.Writer, now time.Time, s *store.Store, short, flagJSON bool) {
+	f := func(a func(eh *store.EntryHandle)) {
+		entries, copyError := s.All()
+		for eh := range entries {
+			a(eh)
+		}
+		if err := copyError(); err != nil {
+			msg.GetLogger().Println(getMessage("cannot iterate over store:", err))
+		}
 	}
 
-	if !short && flagJSON {
-		es := make(map[string]*state.State, len(entries))
-		for id, instance := range entries {
-			es[id.String()] = instance
+	if short { // short output requires identifier only
+		var identifiers []*hst.ID
+		f(func(eh *store.EntryHandle) {
+			if _, err := eh.Load(nil); err != nil { // passes through decode error
+				msg.GetLogger().Println(getMessage("cannot validate state entry header:", err))
+				return
+			}
+			identifiers = append(identifiers, &eh.ID)
+		})
+		slices.SortFunc(identifiers, func(a, b *hst.ID) int { return bytes.Compare(a[:], b[:]) })
+
+		if flagJSON {
+			encodeJSON(log.Fatal, output, short, identifiers)
+		} else {
+			for _, id := range identifiers {
+				mustPrintln(output, shortIdentifier(id))
+			}
 		}
-		printJSON(output, short, es)
 		return
 	}
 
-	// sort state entries by id string to ensure consistency between runs
-	exp := make([]*expandedStateEntry, 0, len(entries))
-	for id, instance := range entries {
-		// gracefully skip nil states
-		if instance == nil {
-			log.Printf("got invalid state entry %s", id.String())
-			continue
+	// long output requires full instance state
+	var instances []*hst.State
+	f(func(eh *store.EntryHandle) {
+		var state hst.State
+		if _, err := eh.Load(&state); err != nil { // passes through decode error
+			msg.GetLogger().Println(getMessage("cannot load state entry:", err))
+			return
 		}
+		instances = append(instances, &state)
+	})
+	slices.SortFunc(instances, func(a, b *hst.State) int { return bytes.Compare(a.ID[:], b.ID[:]) })
 
-		// gracefully skip inconsistent states
-		if id != instance.ID {
-			log.Printf("possible store corruption: entry %s has id %s",
-				id.String(), instance.ID.String())
-			continue
-		}
-		exp = append(exp, &expandedStateEntry{s: id.String(), State: instance})
-	}
-	slices.SortFunc(exp, func(a, b *expandedStateEntry) int { return a.Time.Compare(b.Time) })
-
-	if short {
-		if flagJSON {
-			v := make([]string, len(exp))
-			for i, e := range exp {
-				v[i] = e.s
-			}
-			printJSON(output, short, v)
-		} else {
-			for _, e := range exp {
-				mustPrintln(output, e.s[:8])
-			}
-		}
+	if flagJSON {
+		encodeJSON(log.Fatal, output, short, instances)
 		return
 	}
 
@@ -252,61 +223,48 @@ func printPs(output io.Writer, now time.Time, s state.Store, short, flagJSON boo
 	defer t.MustFlush()
 
 	t.Println("\tInstance\tPID\tApplication\tUptime")
-	for _, e := range exp {
-		if len(e.s) != 1<<5 {
-			// unreachable
-			log.Printf("possible store corruption: invalid instance string %s", e.s)
-			continue
-		}
-
+	for _, instance := range instances {
 		as := "(No configuration information)"
-		if e.Config != nil {
-			as = strconv.Itoa(e.Config.Identity)
-			id := e.Config.ID
+		if instance.Config != nil {
+			as = strconv.Itoa(instance.Config.Identity)
+			id := instance.Config.ID
 			if id == "" {
-				id = "app.hakurei." + e.s[:8]
+				id = "app.hakurei." + shortIdentifier(&instance.ID)
 			}
 			as += " (" + id + ")"
 		}
 		t.Printf("\t%s\t%d\t%s\t%s\n",
-			e.s[:8], e.PID, as, now.Sub(e.Time).Round(time.Second).String())
-	}
-}
-
-type expandedStateEntry struct {
-	s string
-	*state.State
-}
-
-func printJSON(output io.Writer, short bool, v any) {
-	encoder := json.NewEncoder(output)
-	if !short {
-		encoder.SetIndent("", "  ")
-	}
-	if err := encoder.Encode(v); err != nil {
-		log.Fatalf("cannot serialise: %v", err)
+			shortIdentifier(&instance.ID), instance.PID, as, now.Sub(instance.Time).Round(time.Second).String())
 	}
 }
 
+// newPrinter returns a configured, wrapped [tabwriter.Writer].
 func newPrinter(output io.Writer) *tp { return &tp{tabwriter.NewWriter(output, 0, 1, 4, ' ', 0)} }
 
+// tp wraps [tabwriter.Writer] to provide additional formatting methods.
 type tp struct{ *tabwriter.Writer }
 
+// Printf calls [fmt.Fprintf] on the underlying [tabwriter.Writer].
 func (p *tp) Printf(format string, a ...any) {
 	if _, err := fmt.Fprintf(p, format, a...); err != nil {
 		log.Fatalf("cannot write to tabwriter: %v", err)
 	}
 }
+
+// Println calls [fmt.Fprintln] on the underlying [tabwriter.Writer].
 func (p *tp) Println(a ...any) {
 	if _, err := fmt.Fprintln(p, a...); err != nil {
 		log.Fatalf("cannot write to tabwriter: %v", err)
 	}
 }
+
+// MustFlush calls the Flush method of [tabwriter.Writer] and calls [log.Fatalf] on a non-nil error.
 func (p *tp) MustFlush() {
 	if err := p.Writer.Flush(); err != nil {
 		log.Fatalf("cannot flush tabwriter: %v", err)
 	}
 }
+
 func mustPrint(output io.Writer, a ...any) {
 	if _, err := fmt.Fprint(output, a...); err != nil {
 		log.Fatalf("cannot print: %v", err)
@@ -317,3 +275,11 @@ func mustPrintln(output io.Writer, a ...any) {
 		log.Fatalf("cannot print: %v", err)
 	}
 }
+
+// getMessage returns a [message.Error] message if available, or err prefixed with fallback otherwise.
+func getMessage(fallback string, err error) string {
+	if m, ok := message.GetMessage(err); ok {
+		return m
+	}
+	return fmt.Sprintln(fallback, err)
+}

cmd/hsu/conf.go

@@ -0,0 +1,7 @@
+//go:build !rosa
+
+package main
+
+// hsuConfPath is an absolute pathname to the hsu configuration file. Its
+// contents are interpreted by parseConfig.
+const hsuConfPath = "/etc/hsurc"

cmd/hsu/config_rosa.go

@@ -0,0 +1,7 @@
+//go:build rosa
+
+package main
+
+// hsuConfPath is the pathname to the hsu configuration file, specific to
+// Rosa OS. Its contents are interpreted by parseConfig.
+const hsuConfPath = "/system/etc/hsurc"

cmd/hsu/hst.go

@@ -0,0 +1,16 @@
+package main
+
+/* keep in sync with hst */
+
+const (
+	userOffset = 100000
+	rangeSize  = userOffset / 10
+
+	identityStart = 0
+	identityEnd   = appEnd - appStart
+
+	appStart = rangeSize * 1
+	appEnd   = appStart + rangeSize - 1
+)
+
+func toUser(userid, appid uint32) uint32 { return userid*userOffset + appStart + appid }

cmd/hsu/main.go

@@ -1,3 +1,56 @@
+// hsu starts the hakurei shim as the target subordinate user.
+//
+// The hsu program must be installed with the setuid and setgid bit set, and
+// owned by root. A configuration file must be installed at /etc/hsurc with
+// permission bits 0400, and owned by root. Each line of the file specifies a
+// hakurei userid to kernel uid mapping. A line consists of the decimal string
+// representation of the uid of the user wishing to start hakurei containers,
+// followed by a space, followed by the decimal string representation of its
+// userid. Duplicate uid entries are ignored, with the first occurrence taking
+// effect.
+//
+// For example, to map the kernel uid 1000 to the hakurei user id 0:
+//
+//	1000 0
+//
+// # Internals
+//
+// Hakurei and hsu holds pathnames pointing to each other set at link time. For
+// this reason, a distribution of hakurei has fixed installation prefix. Since
+// this program is never invoked by the user, behaviour described in the
+// following paragraphs are considered an internal detail and not covered by the
+// compatibility promise.
+//
+// After checking credentials, hsu checks via /proc/ the absolute pathname of
+// its parent process, and fails if it does not match the hakurei pathname set
+// at link time. This is not a security feature: the priv-side is considered
+// trusted, and this feature makes no attempt to address the racy nature of
+// querying /proc/, or debuggers attached to the parent process. Instead, this
+// aims to discourage misuse and reduce confusion if the user accidentally
+// stumbles upon this program. It also prevents accidental use of the incorrect
+// installation of hsu in some environments.
+//
+// Since target container environment variables are set up in shim via the
+// [container] infrastructure, the environment is used for parameters from the
+// parent process.
+//
+// HAKUREI_SHIM specifies a single byte between '3' and '9' representing the
+// setup pipe file descriptor. It is passed as is to the shim process and is the
+// only value in the environment of the shim process. Since hsurc is not
+// accessible to the parent process, leaving this unset causes hsu to print the
+// corresponding hakurei user id of the parent and terminate.
+//
+// HAKUREI_IDENTITY specifies the identity of the instance being started and is
+// used to produce the kernel uid alongside hakurei user id looked up from hsurc.
+//
+// HAKUREI_GROUPS specifies supplementary groups to inherit from the credentials
+// of the parent process in a ' ' separated list of decimal string
+// representations of gid. This has the unfortunate consequence of allowing
+// users mapped via hsurc to effectively drop group membership, so special care
+// must be taken to ensure this does not lead to an increase in access. This is
+// not applicable to Rosa OS since unsigned code execution is not permitted
+// outside hakurei containers, and is generally nonapplicable to the security
+// model of hakurei, where all untrusted code runs within containers.
 package main
 
 import (
@@ -5,7 +58,8 @@ import (
 	"fmt"
 	"log"
 	"os"
-	"path"
+	"path/filepath"
+	"runtime"
 	"slices"
 	"strconv"
 	"strings"
@@ -13,47 +67,60 @@ import (
 )
 
 const (
-	hsuConfFile = "/etc/hsurc"
-	envShim     = "HAKUREI_SHIM"
-	envAID      = "HAKUREI_APP_ID"
-	envGroups   = "HAKUREI_GROUPS"
-
-	PR_SET_NO_NEW_PRIVS = 0x26
+	// envShim is the name of the environment variable holding a single byte
+	// representing the shim setup pipe file descriptor.
+	envShim = "HAKUREI_SHIM"
+	// envIdentity is the name of the environment variable holding a decimal
+	// string representation of the current application identity.
+	envIdentity = "HAKUREI_IDENTITY"
+	// envGroups holds a ' ' separated list of decimal string representations of
+	// supplementary group gid. Membership requirements are enforced.
+	envGroups = "HAKUREI_GROUPS"
 )
 
+// hakureiPath is the absolute path to Hakurei.
+//
+// This is set by the linker.
+var hakureiPath string
+
 func main() {
+	const PR_SET_NO_NEW_PRIVS = 0x26
+	runtime.LockOSThread()
+
 	log.SetFlags(0)
 	log.SetPrefix("hsu: ")
-	log.SetOutput(os.Stderr)
 
 	if os.Geteuid() != 0 {
 		log.Fatal("this program must be owned by uid 0 and have the setuid bit set")
 	}
+	if os.Getegid() != os.Getgid() {
+		log.Fatal("this program must not have the setgid bit set")
+	}
 
 	puid := os.Getuid()
 	if puid == 0 {
 		log.Fatal("this program must not be started by root")
 	}
 
+	if !filepath.IsAbs(hakureiPath) {
+		log.Fatal("this program is compiled incorrectly")
+		return
+	}
+
 	var toolPath string
-	pexe := path.Join("/proc", strconv.Itoa(os.Getppid()), "exe")
+	pexe := filepath.Join("/proc", strconv.Itoa(os.Getppid()), "exe")
 	if p, err := os.Readlink(pexe); err != nil {
 		log.Fatalf("cannot read parent executable path: %v", err)
 	} else if strings.HasSuffix(p, " (deleted)") {
 		log.Fatal("hakurei executable has been deleted")
-	} else if p != mustCheckPath(hmain) {
+	} else if p != hakureiPath {
 		log.Fatal("this program must be started by hakurei")
 	} else {
 		toolPath = p
 	}
 
-	// uid = 1000000 +
-	//   fid * 10000 +
-	//           aid
-	uid := 1000000
-
 	// refuse to run if hsurc is not protected correctly
-	if s, err := os.Stat(hsuConfFile); err != nil {
+	if s, err := os.Stat(hsuConfPath); err != nil {
 		log.Fatal(err)
 	} else if s.Mode().Perm() != 0400 {
 		log.Fatal("bad hsurc perm")
@@ -62,29 +129,13 @@ func main() {
 	}
 
 	// authenticate before accepting user input
-	if f, err := os.Open(hsuConfFile); err != nil {
-		log.Fatal(err)
-	} else if fid, ok := mustParseConfig(f, puid); !ok {
-		log.Fatalf("uid %d is not in the hsurc file", puid)
-	} else {
-		uid += fid * 10000
-	}
-
-	// allowed aid range 0 to 9999
-	if as, ok := os.LookupEnv(envAID); !ok {
-		log.Fatal("HAKUREI_APP_ID not set")
-	} else if aid, err := parseUint32Fast(as); err != nil || aid < 0 || aid > 9999 {
-		log.Fatal("invalid aid")
-	} else {
-		uid += aid
-	}
+	userid := mustParseConfig(puid)
 
 	// pass through setup fd to shim
 	var shimSetupFd string
 	if s, ok := os.LookupEnv(envShim); !ok {
-		// hakurei requests target uid
-		// print resolved uid and exit
-		fmt.Print(uid)
+		// hakurei requests hsurc user id
+		fmt.Print(userid)
 		os.Exit(0)
 	} else if len(s) != 1 || s[0] > '9' || s[0] < '3' {
 		log.Fatal("HAKUREI_SHIM holds an invalid value")
@@ -92,6 +143,22 @@ func main() {
 		shimSetupFd = s
 	}
 
+	// start is going ahead at this point
+	identity := mustReadIdentity()
+
+	const (
+		// first possible uid outcome
+		uidStart = 10000
+		// last possible uid outcome
+		uidEnd = 999919999
+	)
+	uid := int(toUser(userid, identity))
+
+	// final bounds check to catch any bugs
+	if uid < uidStart || uid >= uidEnd {
+		panic("uid out of bounds")
+	}
+
 	// supplementary groups
 	var suppGroups, suppCurrent []int
 
@@ -119,13 +186,7 @@ func main() {
 		suppGroups = []int{uid}
 	}
 
-	// final bounds check to catch any bugs
-	if uid < 1000000 || uid >= 2000000 {
-		panic("uid out of bounds")
-	}
-
 	// careful! users in the allowlist is effectively allowed to drop groups via hsu
-
 	if err := syscall.Setresgid(uid, uid, uid); err != nil {
 		log.Fatalf("cannot set gid: %v", err)
 	}
@@ -135,10 +196,21 @@ func main() {
 	if err := syscall.Setresuid(uid, uid, uid); err != nil {
 		log.Fatalf("cannot set uid: %v", err)
 	}
-	if _, _, errno := syscall.AllThreadsSyscall(syscall.SYS_PRCTL, PR_SET_NO_NEW_PRIVS, 1, 0); errno != 0 {
+
+	if _, _, errno := syscall.AllThreadsSyscall(
+		syscall.SYS_PRCTL,
+		PR_SET_NO_NEW_PRIVS, 1,
+		0,
+	); errno != 0 {
 		log.Fatalf("cannot set no_new_privs flag: %s", errno.Error())
 	}
-	if err := syscall.Exec(toolPath, []string{"hakurei", "shim"}, []string{envShim + "=" + shimSetupFd}); err != nil {
+
+	if err := syscall.Exec(toolPath, []string{
+		"hakurei",
+		"shim",
+	}, []string{
+		envShim + "=" + shimSetupFd,
+	}); err != nil {
 		log.Fatalf("cannot start shim: %v", err)
 	}
 

cmd/hsu/package.nix

@@ -19,5 +19,5 @@ buildGoModule {
   ldflags = lib.attrsets.foldlAttrs (
     ldflags: name: value:
     ldflags ++ [ "-X main.${name}=${value}" ]
-  ) [ "-s -w" ] { hmain = "${hakurei}/libexec/hakurei"; };
+  ) [ "-s -w" ] { hakureiPath = "${hakurei}/libexec/hakurei"; };
 }

cmd/hsu/parse.go

@@ -6,62 +6,123 @@ import (
 	"fmt"
 	"io"
 	"log"
+	"math"
+	"os"
 	"strings"
 )
 
-func parseUint32Fast(s string) (int, error) {
+const (
+	// useridStart is the first userid.
+	useridStart = 0
+	// useridEnd is the last userid.
+	useridEnd = useridStart + rangeSize - 1
+)
+
+// parseUint32Fast parses a string representation of an unsigned 32-bit integer
+// value using the fast path only. This limits the range of values it is defined
+// in but is perfectly adequate for this use case.
+func parseUint32Fast(s string) (uint32, error) {
 	sLen := len(s)
 	if sLen < 1 {
-		return -1, errors.New("zero length string")
+		return 0, errors.New("zero length string")
 	}
 	if sLen > 10 {
-		return -1, errors.New("string too long")
+		return 0, errors.New("string too long")
 	}
 
-	n := 0
+	var n uint32
 	for i, ch := range []byte(s) {
 		ch -= '0'
 		if ch > 9 {
-			return -1, fmt.Errorf("invalid character '%s' at index %d", string(ch+'0'), i)
+			return 0, fmt.Errorf("invalid character '%s' at index %d", string(ch+'0'), i)
 		}
-		n = n*10 + int(ch)
+		n = n*10 + uint32(ch)
 	}
 	return n, nil
 }
 
-func parseConfig(r io.Reader, puid int) (fid int, ok bool, err error) {
+// parseConfig reads a list of allowed users from r until it encounters puid or
+// [io.EOF].
+//
+// Each line of the file specifies a hakurei userid to kernel uid mapping. A
+// line consists of the string representation of the uid of the user wishing to
+// start hakurei containers, followed by a space, followed by the string
+// representation of its userid. Duplicate uid entries are ignored, with the
+// first occurrence taking effect.
+//
+// All string representations are parsed by calling parseUint32Fast.
+func parseConfig(r io.Reader, puid uint32) (userid uint32, ok bool, err error) {
 	s := bufio.NewScanner(r)
-	var line, puid0 int
+	var (
+		line  uintptr
+		puid0 uint32
+	)
 	for s.Scan() {
 		line++
 
-		// <puid> <fid>
+		// <puid> <userid>
 		lf := strings.SplitN(s.Text(), " ", 2)
 		if len(lf) != 2 {
-			return -1, false, fmt.Errorf("invalid entry on line %d", line)
+			return useridEnd + 1, false, fmt.Errorf("invalid entry on line %d", line)
 		}
 
 		puid0, err = parseUint32Fast(lf[0])
 		if err != nil || puid0 < 1 {
-			return -1, false, fmt.Errorf("invalid parent uid on line %d", line)
+			return useridEnd + 1, false, fmt.Errorf("invalid parent uid on line %d", line)
 		}
 
 		ok = puid0 == puid
 		if ok {
-			// allowed fid range 0 to 99
-			if fid, err = parseUint32Fast(lf[1]); err != nil || fid < 0 || fid > 99 {
-				return -1, false, fmt.Errorf("invalid identity on line %d", line)
+			// userid bound to a range, uint32 size allows this to be increased if needed
+			if userid, err = parseUint32Fast(lf[1]); err != nil ||
+				userid < useridStart || userid > useridEnd {
+				return useridEnd + 1, false, fmt.Errorf("invalid userid on line %d", line)
 			}
 			return
 		}
 	}
-	return -1, false, s.Err()
+	return useridEnd + 1, false, s.Err()
 }
 
-func mustParseConfig(r io.Reader, puid int) (int, bool) {
-	fid, ok, err := parseConfig(r, puid)
-	if err != nil {
+// mustParseConfig calls parseConfig to interpret the contents of hsuConfPath,
+// terminating the program if an error is encountered, the syntax is incorrect,
+// or the current user is not authorised to use hsu because its uid is missing.
+//
+// Therefore, code after this function call can assume an authenticated state.
+//
+// mustParseConfig returns the userid value of the current user.
+func mustParseConfig(puid int) (userid uint32) {
+	if puid > math.MaxUint32 {
+		log.Fatalf("got impossible uid %d", puid)
+	}
+
+	var ok bool
+	if f, err := os.Open(hsuConfPath); err != nil {
+		log.Fatal(err)
+	} else if userid, ok, err = parseConfig(f, uint32(puid)); err != nil {
+		log.Fatal(err)
+	} else if err = f.Close(); err != nil {
 		log.Fatal(err)
 	}
-	return fid, ok
+	if !ok {
+		log.Fatalf("uid %d is not in the hsurc file", puid)
+	}
+
+	return
+}
+
+// mustReadIdentity calls parseUint32Fast to interpret the value stored in envIdentity,
+// terminating the program if the value is not set, malformed, or out of bounds.
+func mustReadIdentity() uint32 {
+	// ranges defined in hst and copied to this package to avoid importing hst
+	if as, ok := os.LookupEnv(envIdentity); !ok {
+		log.Fatal("HAKUREI_IDENTITY not set")
+		panic("unreachable")
+	} else if identity, err := parseUint32Fast(as); err != nil ||
+		identity < identityStart || identity > identityEnd {
+		log.Fatal("invalid identity")
+		panic("unreachable")
+	} else {
+		return identity
+	}
 }

cmd/hsu/parse_test.go

@@ -2,94 +2,105 @@ package main
 
 import (
 	"bytes"
+	"math"
 	"strconv"
 	"testing"
 )
 
-func Test_parseUint32Fast(t *testing.T) {
+func TestParseUint32Fast(t *testing.T) {
+	t.Parallel()
+
 	t.Run("zero-length", func(t *testing.T) {
+		t.Parallel()
+
 		if _, err := parseUint32Fast(""); err == nil || err.Error() != "zero length string" {
 			t.Errorf(`parseUint32Fast(""): error = %v`, err)
 			return
 		}
 	})
+
 	t.Run("overflow", func(t *testing.T) {
+		t.Parallel()
+
 		if _, err := parseUint32Fast("10000000000"); err == nil || err.Error() != "string too long" {
 			t.Errorf("parseUint32Fast: error = %v", err)
 			return
 		}
 	})
+
 	t.Run("invalid byte", func(t *testing.T) {
+		t.Parallel()
+
 		if _, err := parseUint32Fast("meow"); err == nil || err.Error() != "invalid character 'm' at index 0" {
 			t.Errorf(`parseUint32Fast("meow"): error = %v`, err)
 			return
 		}
 	})
-	t.Run("full range", func(t *testing.T) {
-		testRange := func(i, end int) {
+
+	t.Run("range", func(t *testing.T) {
+		t.Parallel()
+
+		testRange := func(i, end uint32) {
 			for ; i < end; i++ {
-				s := strconv.Itoa(i)
+				s := strconv.Itoa(int(i))
 				w := i
 				t.Run("parse "+s, func(t *testing.T) {
 					t.Parallel()
+
 					v, err := parseUint32Fast(s)
 					if err != nil {
-						t.Errorf("parseUint32Fast(%q): error = %v",
-							s, err)
+						t.Errorf("parseUint32Fast(%q): error = %v", s, err)
 						return
 					}
 					if v != w {
-						t.Errorf("parseUint32Fast(%q): got %v",
-							s, v)
+						t.Errorf("parseUint32Fast(%q): got %v", s, v)
 						return
 					}
 				})
 			}
 		}
 
-		testRange(0, 5000)
-		testRange(105000, 110000)
-		testRange(23005000, 23010000)
-		testRange(456005000, 456010000)
-		testRange(7890005000, 7890010000)
+		testRange(0, 2500)
+		testRange(23002500, 23005000)
+		testRange(math.MaxUint32-2500, math.MaxUint32)
 	})
 }
 
-func Test_parseConfig(t *testing.T) {
+func TestParseConfig(t *testing.T) {
+	t.Parallel()
+
 	testCases := []struct {
 		name       string
-		puid, want int
+		puid, want uint32
 		wantErr    string
 		rc         string
 	}{
-		{"empty", 0, -1, "", ``},
-		{"invalid field", 0, -1, "invalid entry on line 1", `9`},
-		{"invalid puid", 0, -1, "invalid parent uid on line 1", `f 9`},
-		{"invalid fid", 1000, -1, "invalid identity on line 1", `1000 f`},
+		{"empty", 0, useridEnd + 1, "", ``},
+		{"invalid field", 0, useridEnd + 1, "invalid entry on line 1", `9`},
+		{"invalid puid", 0, useridEnd + 1, "invalid parent uid on line 1", `f 9`},
+		{"invalid userid", 1000, useridEnd + 1, "invalid userid on line 1", `1000 f`},
 		{"match", 1000, 0, "", `1000 0`},
 	}
 
 	for _, tc := range testCases {
 		t.Run(tc.name, func(t *testing.T) {
-			fid, ok, err := parseConfig(bytes.NewBufferString(tc.rc), tc.puid)
+			t.Parallel()
+
+			userid, ok, err := parseConfig(bytes.NewBufferString(tc.rc), tc.puid)
 			if err == nil && tc.wantErr != "" {
-				t.Errorf("parseConfig: error = %v; wantErr %q",
-					err, tc.wantErr)
+				t.Errorf("parseConfig: error = %v; want %q", err, tc.wantErr)
 				return
 			}
 			if err != nil && err.Error() != tc.wantErr {
-				t.Errorf("parseConfig: error = %q; wantErr %q",
-					err, tc.wantErr)
+				t.Errorf("parseConfig: error = %q; want %q", err, tc.wantErr)
 				return
 			}
-			if ok == (tc.want == -1) {
-				t.Errorf("parseConfig: ok = %v; want %v",
-					ok, tc.want)
+			if ok == (tc.want == useridEnd+1) {
+				t.Errorf("parseConfig: ok = %v; want %v", ok, tc.want)
 				return
 			}
-			if fid != tc.want {
-				t.Errorf("parseConfig: fid = %v; want %v",
-					fid, tc.want)
+			if userid != tc.want {
+				t.Errorf("parseConfig: %v; want %v", userid, tc.want)
 			}
 		})
 	}

cmd/hsu/path.go

@@ -1,20 +0,0 @@
-package main
-
-import (
-	"log"
-	"path"
-)
-
-const compPoison = "INVALIDINVALIDINVALIDINVALIDINVALID"
-
-var (
-	hmain = compPoison
-)
-
-func mustCheckPath(p string) string {
-	if p != compPoison && p != "" && path.IsAbs(p) {
-		return p
-	}
-	log.Fatal("this program is compiled incorrectly")
-	return compPoison
-}

cmd/mbf/cache.go

@@ -0,0 +1,135 @@
+package main
+
+import (
+	"context"
+	"os"
+	"path/filepath"
+	"testing"
+
+	"hakurei.app/check"
+	"hakurei.app/container"
+	"hakurei.app/internal/pkg"
+	"hakurei.app/message"
+)
+
+// cache refers to an instance of [pkg.Cache] that might be open.
+type cache struct {
+	ctx context.Context
+	msg message.Msg
+
+	// Should generally not be used directly.
+	c *pkg.Cache
+
+	cures, jobs int
+	// Primarily to work around missing landlock LSM.
+	hostAbstract bool
+	// Set SCHED_IDLE.
+	idle bool
+	// Unset [pkg.CSuppressInit].
+	verboseInit bool
+	// Loaded artifact of [rosa.QEMU].
+	qemu pkg.Artifact
+
+	base string
+}
+
+// open opens the underlying [pkg.Cache].
+func (cache *cache) open() (err error) {
+	if cache.c != nil {
+		return os.ErrInvalid
+	}
+
+	var base *check.Absolute
+	if cache.base, err = filepath.Abs(cache.base); err != nil {
+		return
+	} else if base, err = check.NewAbs(cache.base); err != nil {
+		return
+	}
+
+	var flags int
+	if cache.idle {
+		flags |= pkg.CSchedIdle
+	}
+	if cache.hostAbstract {
+		flags |= pkg.CHostAbstract
+	}
+	if !cache.verboseInit {
+		flags |= pkg.CSuppressInit
+	}
+
+	done := make(chan struct{})
+	defer close(done)
+	go func() {
+		select {
+		case <-cache.ctx.Done():
+			if testing.Testing() {
+				return
+			}
+			os.Exit(2)
+
+		case <-done:
+			return
+		}
+	}()
+
+	cache.msg.Verbosef("opening cache at %s", base)
+	cache.c, err = pkg.Open(
+		cache.ctx,
+		cache.msg,
+		flags,
+		cache.cures,
+		cache.jobs,
+		base,
+	)
+	if err != nil {
+		return
+	}
+	done <- struct{}{}
+
+	if cache.qemu != nil {
+		var pathname *check.Absolute
+		pathname, _, err = cache.c.Cure(cache.qemu)
+		if err != nil {
+			cache.c.Close()
+			return
+		}
+
+		pkg.RegisterArch("riscv64", container.BinfmtEntry{
+			Offset: 0,
+			Magic:  "\x7fELF\x02\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\xf3\x00",
+			Mask:   "\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff",
+			Interpreter: pathname.Append(
+				"system/bin",
+				"qemu-riscv64",
+			),
+		})
+		pkg.RegisterArch("arm64", container.BinfmtEntry{
+			Offset: 0,
+			Magic:  "\x7fELF\x02\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\xb7\x00",
+			Mask:   "\xff\xff\xff\xff\xff\xff\xff\xfc\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff",
+			Interpreter: pathname.Append(
+				"system/bin",
+				"qemu-aarch64",
+			),
+		})
+	}
+
+	return
+}
+
+// Close closes the underlying [pkg.Cache] if it is open.
+func (cache *cache) Close() {
+	if cache.c != nil {
+		cache.c.Close()
+	}
+}
+
+// Do calls f on the underlying cache and returns its error value.
+func (cache *cache) Do(f func(cache *pkg.Cache) error) error {
+	if cache.c == nil {
+		if err := cache.open(); err != nil {
+			return err
+		}
+	}
+	return f(cache.c)
+}

cmd/mbf/cache_test.go

@@ -0,0 +1,37 @@
+package main
+
+import (
+	"log"
+	"os"
+	"testing"
+
+	"hakurei.app/internal/pkg"
+	"hakurei.app/message"
+)
+
+func TestCache(t *testing.T) {
+	t.Parallel()
+
+	cm := cache{
+		ctx:  t.Context(),
+		msg:  message.New(log.New(os.Stderr, "check: ", 0)),
+		base: t.TempDir(),
+
+		hostAbstract: true, idle: true,
+	}
+	defer cm.Close()
+	cm.Close()
+
+	if err := cm.open(); err != nil {
+		t.Fatalf("open: error = %v", err)
+	}
+	if err := cm.open(); err != os.ErrInvalid {
+		t.Errorf("(duplicate) open: error = %v", err)
+	}
+
+	if err := cm.Do(func(cache *pkg.Cache) error {
+		return cache.Scrub(0)
+	}); err != nil {
+		t.Errorf("Scrub: error = %v", err)
+	}
+}

cmd/mbf/daemon.go

@@ -0,0 +1,354 @@
+package main
+
+import (
+	"context"
+	"encoding/binary"
+	"errors"
+	"io"
+	"log"
+	"math"
+	"net"
+	"os"
+	"sync"
+	"syscall"
+	"testing"
+	"time"
+	"unique"
+
+	"hakurei.app/check"
+	"hakurei.app/internal/pkg"
+)
+
+// daemonTimeout is the maximum amount of time cureFromIR will wait on I/O.
+const daemonTimeout = 30 * time.Second
+
+// daemonDeadline returns the deadline corresponding to daemonTimeout, or the
+// zero value when running in a test.
+func daemonDeadline() time.Time {
+	if testing.Testing() {
+		return time.Time{}
+	}
+	return time.Now().Add(daemonTimeout)
+}
+
+const (
+	// remoteNoReply notifies that the client will not receive a cure reply.
+	remoteNoReply = 1 << iota
+)
+
+// cureFromIR services an IR curing request.
+func cureFromIR(
+	cache *pkg.Cache,
+	conn net.Conn,
+	flags uint64,
+) (pkg.Artifact, error) {
+	a, decodeErr := cache.NewDecoder(conn).Decode()
+	if decodeErr != nil {
+		_, err := conn.Write([]byte("\x00" + decodeErr.Error()))
+		return nil, errors.Join(decodeErr, err, conn.Close())
+	}
+
+	pathname, _, cureErr := cache.Cure(a)
+	if flags&remoteNoReply != 0 {
+		return a, errors.Join(cureErr, conn.Close())
+	}
+	if err := conn.SetWriteDeadline(daemonDeadline()); err != nil {
+		return a, errors.Join(cureErr, err, conn.Close())
+	}
+	if cureErr != nil {
+		_, err := conn.Write([]byte("\x00" + cureErr.Error()))
+		return a, errors.Join(cureErr, err, conn.Close())
+	}
+	_, err := conn.Write([]byte(pathname.String()))
+	if testing.Testing() && errors.Is(err, io.ErrClosedPipe) {
+		return a, nil
+	}
+	return a, errors.Join(err, conn.Close())
+}
+
+const (
+	// specialCancel is a message consisting of a single identifier referring
+	// to a curing artifact to be cancelled.
+	specialCancel = iota
+	// specialAbort requests for all pending cures to be aborted. It has no
+	// message body.
+	specialAbort
+
+	// remoteSpecial denotes a special message with custom layout.
+	remoteSpecial = math.MaxUint64
+)
+
+// writeSpecialHeader writes the header of a remoteSpecial message.
+func writeSpecialHeader(conn net.Conn, kind uint64) error {
+	var sh [16]byte
+	binary.LittleEndian.PutUint64(sh[:], remoteSpecial)
+	binary.LittleEndian.PutUint64(sh[8:], kind)
+	if n, err := conn.Write(sh[:]); err != nil {
+		return err
+	} else if n != len(sh) {
+		return io.ErrShortWrite
+	}
+	return nil
+}
+
+// cancelIdent reads an identifier from conn and cancels the corresponding cure.
+func cancelIdent(
+	cache *pkg.Cache,
+	conn net.Conn,
+) (*pkg.ID, bool, error) {
+	var ident pkg.ID
+	if _, err := io.ReadFull(conn, ident[:]); err != nil {
+		return nil, false, errors.Join(err, conn.Close())
+	}
+	ok := cache.Cancel(unique.Make(ident))
+	return &ident, ok, conn.Close()
+}
+
+// serve services connections from a [net.UnixListener].
+func serve(
+	ctx context.Context,
+	log *log.Logger,
+	cm *cache,
+	ul *net.UnixListener,
+) error {
+	ul.SetUnlinkOnClose(true)
+	if cm.c == nil {
+		if err := cm.open(); err != nil {
+			return errors.Join(err, ul.Close())
+		}
+	}
+
+	var wg sync.WaitGroup
+	defer wg.Wait()
+
+	wg.Go(func() {
+		for {
+			if ctx.Err() != nil {
+				break
+			}
+
+			conn, err := ul.AcceptUnix()
+			if err != nil {
+				if !errors.Is(err, os.ErrDeadlineExceeded) {
+					log.Println(err)
+				}
+				continue
+			}
+			wg.Go(func() {
+				done := make(chan struct{})
+				defer close(done)
+				go func() {
+					select {
+					case <-ctx.Done():
+						_ = conn.SetDeadline(time.Now())
+
+					case <-done:
+						return
+					}
+				}()
+
+				if _err := conn.SetReadDeadline(daemonDeadline()); _err != nil {
+					log.Println(_err)
+					if _err = conn.Close(); _err != nil {
+						log.Println(_err)
+					}
+					return
+				}
+
+				var word [8]byte
+				if _, _err := io.ReadFull(conn, word[:]); _err != nil {
+					log.Println(_err)
+					if _err = conn.Close(); _err != nil {
+						log.Println(_err)
+					}
+					return
+				}
+				flags := binary.LittleEndian.Uint64(word[:])
+
+				if flags == remoteSpecial {
+					if _, _err := io.ReadFull(conn, word[:]); _err != nil {
+						log.Println(_err)
+						if _err = conn.Close(); _err != nil {
+							log.Println(_err)
+						}
+						return
+					}
+					switch special := binary.LittleEndian.Uint64(word[:]); special {
+					default:
+						log.Printf("invalid special %d", special)
+
+					case specialCancel:
+						if id, ok, _err := cancelIdent(cm.c, conn); _err != nil {
+							log.Println(_err)
+						} else if !ok {
+							log.Println(
+								"attempting to cancel invalid artifact",
+								pkg.Encode(*id),
+							)
+						} else {
+							log.Println(
+								"cancelled artifact",
+								pkg.Encode(*id),
+							)
+						}
+
+					case specialAbort:
+						log.Println("aborting all pending cures")
+						cm.c.Abort()
+						if _err := conn.Close(); _err != nil {
+							log.Println(_err)
+						}
+					}
+
+					return
+				}
+
+				if a, _err := cureFromIR(cm.c, conn, flags); _err != nil {
+					log.Println(_err)
+				} else {
+					log.Printf(
+						"fulfilled artifact %s",
+						pkg.Encode(cm.c.Ident(a).Value()),
+					)
+				}
+			})
+		}
+	})
+
+	<-ctx.Done()
+	if err := ul.SetDeadline(time.Now()); err != nil {
+		return errors.Join(err, ul.Close())
+	}
+	wg.Wait()
+	return ul.Close()
+}
+
+// dial wraps [net.DialUnix] with a context.
+func dial(ctx context.Context, addr *net.UnixAddr) (
+	done chan<- struct{},
+	conn *net.UnixConn,
+	err error,
+) {
+	conn, err = net.DialUnix("unix", nil, addr)
+	if err != nil {
+		return
+	}
+
+	d := make(chan struct{})
+	done = d
+	go func() {
+		select {
+		case <-ctx.Done():
+			_ = conn.SetDeadline(time.Now())
+
+		case <-d:
+			return
+		}
+	}()
+	return
+}
+
+// cureRemote cures a [pkg.Artifact] on a daemon.
+func cureRemote(
+	ctx context.Context,
+	addr *net.UnixAddr,
+	a pkg.Artifact,
+	flags uint64,
+) (*check.Absolute, error) {
+	if flags == remoteSpecial {
+		return nil, syscall.EINVAL
+	}
+
+	done, conn, err := dial(ctx, addr)
+	if err != nil {
+		return nil, err
+	}
+	defer close(done)
+
+	if n, flagErr := conn.Write(binary.LittleEndian.AppendUint64(nil, flags)); flagErr != nil {
+		return nil, errors.Join(flagErr, conn.Close())
+	} else if n != 8 {
+		return nil, errors.Join(io.ErrShortWrite, conn.Close())
+	}
+
+	if err = pkg.NewIR().EncodeAll(conn, a); err != nil {
+		return nil, errors.Join(err, conn.Close())
+	} else if err = conn.CloseWrite(); err != nil {
+		return nil, errors.Join(err, conn.Close())
+	}
+
+	if flags&remoteNoReply != 0 {
+		return nil, conn.Close()
+	}
+
+	payload, recvErr := io.ReadAll(conn)
+	if err = errors.Join(recvErr, conn.Close()); err != nil {
+		if errors.Is(err, os.ErrDeadlineExceeded) {
+			if cancelErr := ctx.Err(); cancelErr != nil {
+				err = cancelErr
+			}
+		}
+		return nil, err
+	}
+
+	if len(payload) > 0 && payload[0] == 0 {
+		return nil, errors.New(string(payload[1:]))
+	}
+
+	var p *check.Absolute
+	p, err = check.NewAbs(string(payload))
+	return p, err
+}
+
+// cancelRemote cancels a [pkg.Artifact] curing on a daemon.
+func cancelRemote(
+	ctx context.Context,
+	addr *net.UnixAddr,
+	a pkg.Artifact,
+	wait bool,
+) error {
+	done, conn, err := dial(ctx, addr)
+	if err != nil {
+		return err
+	}
+	defer close(done)
+
+	if err = writeSpecialHeader(conn, specialCancel); err != nil {
+		return errors.Join(err, conn.Close())
+	}
+
+	var n int
+	id := pkg.NewIR().Ident(a).Value()
+	if n, err = conn.Write(id[:]); err != nil {
+		return errors.Join(err, conn.Close())
+	} else if n != len(id) {
+		return errors.Join(io.ErrShortWrite, conn.Close())
+	}
+	if wait {
+		if _, err = conn.Read(make([]byte, 1)); err == io.EOF {
+			err = nil
+		}
+	}
+	return errors.Join(err, conn.Close())
+}
+
+// abortRemote aborts all [pkg.Artifact] curing on a daemon.
+func abortRemote(
+	ctx context.Context,
+	addr *net.UnixAddr,
+	wait bool,
+) error {
+	done, conn, err := dial(ctx, addr)
+	if err != nil {
+		return err
+	}
+	defer close(done)
+
+	err = writeSpecialHeader(conn, specialAbort)
+	if wait && err == nil {
+		if _, err = conn.Read(make([]byte, 1)); err == io.EOF {
+			err = nil
+		}
+	}
+	return errors.Join(err, conn.Close())
+}

cmd/mbf/daemon_test.go

@@ -0,0 +1,146 @@
+package main
+
+import (
+	"bytes"
+	"context"
+	"errors"
+	"io"
+	"log"
+	"net"
+	"os"
+	"path/filepath"
+	"slices"
+	"strings"
+	"testing"
+	"time"
+
+	"hakurei.app/check"
+	"hakurei.app/internal/pkg"
+	"hakurei.app/message"
+)
+
+func TestNoReply(t *testing.T) {
+	t.Parallel()
+	if !daemonDeadline().IsZero() {
+		t.Fatal("daemonDeadline did not return the zero value")
+	}
+
+	c, err := pkg.Open(
+		t.Context(),
+		message.New(log.New(os.Stderr, "cir: ", 0)),
+		0, 0, 0,
+		check.MustAbs(t.TempDir()),
+	)
+	if err != nil {
+		t.Fatalf("Open: error = %v", err)
+	}
+	defer c.Close()
+
+	client, server := net.Pipe()
+	done := make(chan struct{})
+	go func() {
+		defer close(done)
+		go func() {
+			<-t.Context().Done()
+			if _err := client.SetDeadline(time.Now()); _err != nil && !errors.Is(_err, io.ErrClosedPipe) {
+				panic(_err)
+			}
+		}()
+
+		if _err := c.EncodeAll(
+			client,
+			pkg.NewFile("check", []byte{0}),
+		); _err != nil {
+			panic(_err)
+		} else if _err = client.Close(); _err != nil {
+			panic(_err)
+		}
+	}()
+
+	a, cureErr := cureFromIR(c, server, remoteNoReply)
+	if cureErr != nil {
+		t.Fatalf("cureFromIR: error = %v", cureErr)
+	}
+
+	<-done
+	wantIdent := pkg.MustDecode("fiZf-ZY_Yq6qxJNrHbMiIPYCsGkUiKCRsZrcSELXTqZWtCnESlHmzV5ThhWWGGYG")
+	if gotIdent := c.Ident(a).Value(); gotIdent != wantIdent {
+		t.Errorf(
+			"cureFromIR: %s, want %s",
+			pkg.Encode(gotIdent), pkg.Encode(wantIdent),
+		)
+	}
+}
+
+func TestDaemon(t *testing.T) {
+	t.Parallel()
+
+	var buf bytes.Buffer
+	logger := log.New(&buf, "daemon: ", 0)
+
+	addr := net.UnixAddr{
+		Name: filepath.Join(t.TempDir(), "daemon"),
+		Net:  "unix",
+	}
+
+	ctx, cancel := context.WithCancel(t.Context())
+	defer cancel()
+
+	cm := cache{
+		ctx:  ctx,
+		msg:  message.New(logger),
+		base: t.TempDir(),
+	}
+	defer cm.Close()
+
+	ul, err := net.ListenUnix("unix", &addr)
+	if err != nil {
+		t.Fatalf("ListenUnix: error = %v", err)
+	}
+
+	done := make(chan struct{})
+	go func() {
+		defer close(done)
+		if _err := serve(ctx, logger, &cm, ul); _err != nil {
+			panic(_err)
+		}
+	}()
+
+	if err = cancelRemote(ctx, &addr, pkg.NewFile("nonexistent", nil), true); err != nil {
+		t.Fatalf("cancelRemote: error = %v", err)
+	}
+
+	if err = abortRemote(ctx, &addr, true); err != nil {
+		t.Fatalf("abortRemote: error = %v", err)
+	}
+
+	// keep this last for synchronisation
+	var p *check.Absolute
+	p, err = cureRemote(ctx, &addr, pkg.NewFile("check", []byte{0}), 0)
+	if err != nil {
+		t.Fatalf("cureRemote: error = %v", err)
+	}
+
+	cancel()
+	<-done
+
+	const want = "fiZf-ZY_Yq6qxJNrHbMiIPYCsGkUiKCRsZrcSELXTqZWtCnESlHmzV5ThhWWGGYG"
+	if got := filepath.Base(p.String()); got != want {
+		t.Errorf("cureRemote: %s, want %s", got, want)
+	}
+
+	wantLog := []string{
+		"",
+		"daemon: aborting all pending cures",
+		"daemon: attempting to cancel invalid artifact kQm9fmnCmXST1-MMmxzcau2oKZCXXrlZydo4PkeV5hO_2PKfeC8t98hrbV_ZZx_j",
+		"daemon: fulfilled artifact fiZf-ZY_Yq6qxJNrHbMiIPYCsGkUiKCRsZrcSELXTqZWtCnESlHmzV5ThhWWGGYG",
+	}
+	gotLog := strings.Split(buf.String(), "\n")
+	slices.Sort(gotLog)
+	if !slices.Equal(gotLog, wantLog) {
+		t.Errorf(
+			"serve: logged\n%s\nwant\n%s",
+			strings.Join(gotLog, "\n"), strings.Join(wantLog, "\n"),
+		)
+	}
+}

cmd/mbf/info.go

@@ -0,0 +1,118 @@
+package main
+
+import (
+	"errors"
+	"fmt"
+	"io"
+	"os"
+	"strings"
+	"unique"
+
+	"hakurei.app/internal/pkg"
+	"hakurei.app/internal/rosa"
+)
+
+// commandInfo implements the info subcommand.
+func commandInfo(
+	cm *cache,
+	args []string,
+	w io.Writer,
+	writeStatus bool,
+	r *rosa.Report,
+) (err error) {
+	if len(args) == 0 {
+		return errors.New("info requires at least 1 argument")
+	}
+
+	// recovered by HandleAccess
+	mustPrintln := func(a ...any) {
+		if _, _err := fmt.Fprintln(w, a...); _err != nil {
+			panic(_err)
+		}
+	}
+	mustPrint := func(a ...any) {
+		if _, _err := fmt.Fprint(w, a...); _err != nil {
+			panic(_err)
+		}
+	}
+
+	t := rosa.Native().Std()
+	for i, name := range args {
+		handle := rosa.ArtifactH(unique.Make(name))
+		if meta := rosa.Native().Get(handle); meta == nil {
+			return fmt.Errorf("unknown artifact %q", name)
+		} else {
+			var suffix string
+
+			a, version := t.MustLoad(handle)
+			if version != rosa.Unversioned {
+				suffix += "-" + version
+			}
+			mustPrintln("name        : " + name + suffix)
+
+			mustPrintln("description : " + meta.Description)
+			if meta.Website != "" {
+				mustPrintln("website     : " +
+					strings.TrimSuffix(meta.Website, "/"))
+			}
+			if len(meta.Dependencies) > 0 {
+				mustPrint("depends on  :")
+				for _, d := range meta.Dependencies {
+					s := rosa.Native().MustGet(d).Name
+					if _, _version := t.Load(d); _version != rosa.Unversioned {
+						s += "-" + _version
+					}
+					mustPrint(" " + s)
+				}
+				mustPrintln()
+			}
+
+			const statusPrefix = "status      : "
+			if writeStatus {
+				if r == nil {
+					var f io.ReadSeekCloser
+					err = cm.Do(func(cache *pkg.Cache) (err error) {
+						f, err = cache.OpenStatus(a)
+						return
+					})
+					if err != nil {
+						if errors.Is(err, os.ErrNotExist) {
+							mustPrintln(
+								statusPrefix + "not yet cured",
+							)
+						} else {
+							return
+						}
+					} else {
+						mustPrint(statusPrefix)
+						_, err = io.Copy(w, f)
+						if err = errors.Join(err, f.Close()); err != nil {
+							return
+						}
+					}
+				} else if err = cm.Do(func(cache *pkg.Cache) (err error) {
+					status, n := r.ArtifactOf(cache.Ident(a))
+					if status == nil {
+						mustPrintln(
+							statusPrefix + "not in report",
+						)
+					} else {
+						mustPrintln("size        :", n)
+						mustPrint(statusPrefix)
+						if _, err = w.Write(status); err != nil {
+							return
+						}
+					}
+					return
+				}); err != nil {
+					return
+				}
+			}
+
+			if i != len(args)-1 {
+				mustPrintln()
+			}
+		}
+	}
+	return nil
+}

cmd/mbf/info_test.go

@@ -0,0 +1,190 @@
+package main
+
+import (
+	"context"
+	"fmt"
+	"log"
+	"os"
+	"path/filepath"
+	"reflect"
+	"strings"
+	"syscall"
+	"testing"
+	"unique"
+	"unsafe"
+
+	"hakurei.app/internal/pkg"
+	"hakurei.app/internal/rosa"
+	"hakurei.app/message"
+)
+
+func TestInfo(t *testing.T) {
+	t.Parallel()
+
+	_t := rosa.Native().Std()
+	_, qemuVersion := _t.Load(rosa.QEMU)
+	_, glibVersion := _t.Load(rosa.GLib)
+	zlib, zlibVersion := _t.Load(rosa.Zlib)
+	_, zstdVersion := _t.Load(rosa.Zstd)
+	_, hakureiVersion := _t.Load(rosa.Hakurei)
+	_, hakureiDistVersion := _t.Load(rosa.HakureiDist)
+
+	testCases := []struct {
+		name    string
+		args    []string
+		status  map[string]string
+		report  string
+		want    string
+		wantErr any
+	}{
+		{"qemu", []string{"qemu"}, nil, "", `
+name        : qemu-` + qemuVersion + `
+description : a generic and open source machine emulator and virtualizer
+website     : https://www.qemu.org
+depends on  : glib-` + glibVersion + ` zstd-` + zstdVersion + `
+`, nil},
+
+		{"multi", []string{"hakurei", "hakurei-dist"}, nil, "", `
+name        : hakurei-` + hakureiVersion + `
+description : low-level userspace tooling for Rosa OS
+website     : https://hakurei.app
+
+name        : hakurei-dist-` + hakureiDistVersion + `
+description : low-level userspace tooling for Rosa OS (distribution tarball)
+website     : https://hakurei.app
+`, nil},
+
+		{"nonexistent", []string{"zlib", "\x00"}, nil, "", `
+name        : zlib-` + zlibVersion + `
+description : lossless data-compression library
+website     : https://zlib.net
+
+`, fmt.Errorf("unknown artifact %q", "\x00")},
+
+		{"status cache", []string{"zlib", "zstd"}, map[string]string{
+			"zstd":    "internal/pkg (amd64) on satori\n",
+			"hakurei": "internal/pkg (amd64) on satori\n\n",
+		}, "", `
+name        : zlib-` + zlibVersion + `
+description : lossless data-compression library
+website     : https://zlib.net
+status      : not yet cured
+
+name        : zstd-` + zstdVersion + `
+description : a fast compression algorithm
+website     : https://facebook.github.io/zstd
+status      : internal/pkg (amd64) on satori
+`, nil},
+
+		{"status cache perm", []string{"zlib"}, map[string]string{
+			"zlib": "\x00",
+		}, "", `
+name        : zlib-` + zlibVersion + `
+description : lossless data-compression library
+website     : https://zlib.net
+`, func(cm *cache) error {
+			return &os.PathError{
+				Op:   "open",
+				Path: filepath.Join(cm.base, "status", pkg.Encode(cm.c.Ident(zlib).Value())),
+				Err:  syscall.EACCES,
+			}
+		}},
+
+		{"status report", []string{"zlib"}, nil, strings.Repeat("\x00", len(pkg.Checksum{})+8), `
+name        : zlib-` + zlibVersion + `
+description : lossless data-compression library
+website     : https://zlib.net
+status      : not in report
+`, nil},
+	}
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			t.Parallel()
+
+			var (
+				cm  *cache
+				buf strings.Builder
+				r   *rosa.Report
+			)
+
+			if tc.status != nil || tc.report != "" {
+				cm = &cache{
+					ctx:  context.Background(),
+					msg:  message.New(log.New(os.Stderr, "info: ", 0)),
+					base: t.TempDir(),
+				}
+				defer cm.Close()
+			}
+
+			if tc.report != "" {
+				pathname := filepath.Join(t.TempDir(), "report")
+				err := os.WriteFile(
+					pathname,
+					unsafe.Slice(unsafe.StringData(tc.report), len(tc.report)),
+					0400,
+				)
+				if err != nil {
+					t.Fatal(err)
+				}
+
+				r, err = rosa.OpenReport(pathname)
+				if err != nil {
+					t.Fatal(err)
+				}
+				defer func() {
+					if err = r.Close(); err != nil {
+						t.Fatal(err)
+					}
+				}()
+			}
+
+			if tc.status != nil {
+				for name, status := range tc.status {
+					a, _ := _t.Load(rosa.ArtifactH(unique.Make(name)))
+					if a == nil {
+						t.Fatalf("invalid name %q", name)
+					}
+					perm := os.FileMode(0400)
+					if status == "\x00" {
+						perm = 0
+					}
+					if err := cm.Do(func(cache *pkg.Cache) error {
+						return os.WriteFile(filepath.Join(
+							cm.base,
+							"status",
+							pkg.Encode(cache.Ident(a).Value()),
+						), unsafe.Slice(unsafe.StringData(status), len(status)), perm)
+					}); err != nil {
+						t.Fatalf("Do: error = %v", err)
+					}
+				}
+			}
+
+			var wantErr error
+			switch c := tc.wantErr.(type) {
+			case error:
+				wantErr = c
+			case func(cm *cache) error:
+				wantErr = c(cm)
+			default:
+				if tc.wantErr != nil {
+					t.Fatalf("invalid wantErr %#v", tc.wantErr)
+				}
+			}
+
+			if err := commandInfo(
+				cm,
+				tc.args,
+				&buf,
+				cm != nil,
+				r,
+			); !reflect.DeepEqual(err, wantErr) {
+				t.Fatalf("commandInfo: error = %v, want %v", err, wantErr)
+			}
+
+			if got := buf.String(); got != strings.TrimPrefix(tc.want, "\n") {
+				t.Errorf("commandInfo:\n%s\nwant\n%s", got, tc.want)
+			}
+		})
+	}
+}

cmd/mbf/internal/pkgserver/api.go

@@ -0,0 +1,202 @@
+// Package pkgserver implements the package metadata service backend.
+package pkgserver
+
+import (
+	"context"
+	"encoding/json"
+	"log"
+	"net/http"
+	"net/url"
+	"path"
+	"strconv"
+	"sync"
+	"time"
+
+	"hakurei.app/internal/info"
+	"hakurei.app/internal/rosa"
+)
+
+// for lazy initialisation of serveInfo
+var (
+	infoPayload struct {
+		// Current package count.
+		Count int `json:"count"`
+		// Hakurei version, set at link time.
+		HakureiVersion string `json:"hakurei_version"`
+	}
+	infoPayloadOnce sync.Once
+)
+
+// handleInfo writes constant system information.
+func handleInfo(w http.ResponseWriter, _ *http.Request) {
+	infoPayloadOnce.Do(func() {
+		infoPayload.Count = int(rosa.Native().Count())
+		infoPayload.HakureiVersion = info.Version()
+	})
+	// TODO(mae): cache entire response if no additional fields are planned
+	writeAPIPayload(w, infoPayload)
+}
+
+// newStatusHandler returns a [http.HandlerFunc] that offers status files for
+// viewing or download, if available.
+func (index *packageIndex) newStatusHandler(disposition bool) http.HandlerFunc {
+	return func(w http.ResponseWriter, r *http.Request) {
+		m, ok := index.names[path.Base(r.URL.Path)]
+		if !ok || !m.HasReport {
+			http.NotFound(w, r)
+			return
+		}
+
+		contentType := "text/plain; charset=utf-8"
+		if disposition {
+			contentType = "application/octet-stream"
+
+			// quoting like this is unsound, but okay, because metadata is hardcoded
+			contentDisposition := `attachment; filename="`
+			contentDisposition += m.Name + "-"
+			if m.Version != "" {
+				contentDisposition += m.Version + "-"
+			}
+			contentDisposition += m.ids + `.log"`
+			w.Header().Set("Content-Disposition", contentDisposition)
+		}
+		w.Header().Set("Content-Type", contentType)
+		w.Header().Set("Cache-Control", "no-cache, no-store, must-revalidate")
+		if err := func() (err error) {
+			defer index.handleAccess(&err)()
+			_, err = w.Write(m.status)
+			return
+		}(); err != nil {
+			log.Println(err)
+			http.Error(
+				w, "cannot deliver status, contact maintainers",
+				http.StatusInternalServerError,
+			)
+		}
+	}
+}
+
+// handleGet writes a slice of metadata with specified order.
+func (index *packageIndex) handleGet(w http.ResponseWriter, r *http.Request) {
+	q := r.URL.Query()
+	limit, err := strconv.Atoi(q.Get("limit"))
+	if err != nil || limit > 100 || limit < 1 {
+		http.Error(
+			w, "limit must be an integer between 1 and 100",
+			http.StatusBadRequest,
+		)
+		return
+	}
+	i, err := strconv.Atoi(q.Get("index"))
+	if err != nil || i >= len(index.sorts[0]) || i < 0 {
+		http.Error(
+			w, "index must be an integer between 0 and "+
+				strconv.Itoa(len(index.sorts[0])-1),
+			http.StatusBadRequest,
+		)
+		return
+	}
+	sort, err := strconv.Atoi(q.Get("sort"))
+	if err != nil || sort >= len(index.sorts) || sort < 0 {
+		http.Error(
+			w, "sort must be an integer between 0 and "+
+				strconv.Itoa(sortOrderEnd),
+			http.StatusBadRequest,
+		)
+		return
+	}
+	values := index.sorts[sort][i:min(i+limit, len(index.sorts[sort]))]
+	writeAPIPayload(w, &struct {
+		Values []*metadata `json:"values"`
+	}{values})
+}
+
+func (index *packageIndex) handleSearch(w http.ResponseWriter, r *http.Request) {
+	q := r.URL.Query()
+	limit, err := strconv.Atoi(q.Get("limit"))
+	if err != nil || limit > 100 || limit < 1 {
+		http.Error(
+			w, "limit must be an integer between 1 and 100",
+			http.StatusBadRequest,
+		)
+		return
+	}
+	i, err := strconv.Atoi(q.Get("index"))
+	if err != nil || i >= len(index.sorts[0]) || i < 0 {
+		http.Error(
+			w, "index must be an integer between 0 and "+
+				strconv.Itoa(len(index.sorts[0])-1),
+			http.StatusBadRequest,
+		)
+		return
+	}
+	search, err := url.QueryUnescape(q.Get("search"))
+	if len(search) > 100 || err != nil {
+		http.Error(
+			w, "search must be a string between 0 and 100 characters long",
+			http.StatusBadRequest,
+		)
+		return
+	}
+	desc := q.Get("desc") == "true"
+	n, res, err := index.performSearchQuery(limit, i, search, desc)
+	if err != nil {
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+	}
+	writeAPIPayload(w, &struct {
+		Count  int            `json:"count"`
+		Values []searchResult `json:"values"`
+	}{n, res})
+}
+
+// apiVersion is the name of the current API revision, as part of the pattern.
+const apiVersion = "v1"
+
+// registerAPI registers API handler functions.
+func (index *packageIndex) registerAPI(mux *http.ServeMux) {
+	mux.HandleFunc("GET /api/"+apiVersion+"/info", handleInfo)
+	mux.HandleFunc("GET /api/"+apiVersion+"/get", index.handleGet)
+	mux.HandleFunc("GET /api/"+apiVersion+"/search", index.handleSearch)
+	mux.HandleFunc("GET /api/"+apiVersion+"/status/", index.newStatusHandler(false))
+	mux.HandleFunc("GET /status/", index.newStatusHandler(true))
+}
+
+// Register arranges for mux to service API requests.
+func Register(ctx context.Context, mux *http.ServeMux, report *rosa.Report) error {
+	var index packageIndex
+	index.search = make(searchCache)
+	if err := index.populate(report); err != nil {
+		return err
+	}
+	ticker := time.NewTicker(1 * time.Minute)
+	go func() {
+		for {
+			select {
+			case <-ctx.Done():
+				ticker.Stop()
+				return
+			case <-ticker.C:
+				index.search.clean()
+			}
+		}
+	}()
+	index.registerAPI(mux)
+	return nil
+}
+
+// writeAPIPayload sets headers common to API responses and encodes payload as
+// JSON for the response body.
+func writeAPIPayload(w http.ResponseWriter, payload any) {
+	w.Header().Set("Content-Type", "application/json; charset=utf-8")
+	w.Header().Set("Cache-Control", "no-cache, no-store, must-revalidate")
+	w.Header().Set("Pragma", "no-cache")
+	w.Header().Set("Expires", "0")
+
+	if err := json.NewEncoder(w).Encode(payload); err != nil {
+		log.Println(err)
+		http.Error(
+			w, "cannot encode payload, contact maintainers",
+			http.StatusInternalServerError,
+		)
+	}
+}

cmd/mbf/internal/pkgserver/api_test.go

@@ -0,0 +1,110 @@
+package pkgserver
+
+import (
+	"net/http"
+	"net/http/httptest"
+	"strconv"
+	"testing"
+
+	"hakurei.app/internal/info"
+	"hakurei.app/internal/rosa"
+)
+
+// prefix is prepended to every API path.
+const prefix = "/api/" + apiVersion + "/"
+
+func TestAPIInfo(t *testing.T) {
+	t.Parallel()
+
+	w := httptest.NewRecorder()
+	handleInfo(w, httptest.NewRequestWithContext(
+		t.Context(),
+		http.MethodGet,
+		prefix+"info",
+		nil,
+	))
+
+	resp := w.Result()
+	checkStatus(t, resp, http.StatusOK)
+	checkAPIHeader(t, w.Header())
+
+	checkPayload(t, resp, struct {
+		Count          int    `json:"count"`
+		HakureiVersion string `json:"hakurei_version"`
+	}{rosa.Native().Count(), info.Version()})
+}
+
+func TestAPIGet(t *testing.T) {
+	t.Parallel()
+	const target = prefix + "get"
+
+	index := newIndex(t)
+	newRequest := func(suffix string) *httptest.ResponseRecorder {
+		w := httptest.NewRecorder()
+		index.handleGet(w, httptest.NewRequestWithContext(
+			t.Context(),
+			http.MethodGet,
+			target+suffix,
+			nil,
+		))
+		return w
+	}
+
+	checkValidate := func(t *testing.T, suffix string, vmin, vmax int, wantErr string) {
+		t.Run("invalid", func(t *testing.T) {
+			t.Parallel()
+
+			w := newRequest("?" + suffix + "=invalid")
+			resp := w.Result()
+			checkError(t, resp, wantErr, http.StatusBadRequest)
+		})
+
+		t.Run("min", func(t *testing.T) {
+			t.Parallel()
+
+			w := newRequest("?" + suffix + "=" + strconv.Itoa(vmin-1))
+			resp := w.Result()
+			checkError(t, resp, wantErr, http.StatusBadRequest)
+
+			w = newRequest("?" + suffix + "=" + strconv.Itoa(vmin))
+			resp = w.Result()
+			checkStatus(t, resp, http.StatusOK)
+		})
+
+		t.Run("max", func(t *testing.T) {
+			t.Parallel()
+
+			w := newRequest("?" + suffix + "=" + strconv.Itoa(vmax+1))
+			resp := w.Result()
+			checkError(t, resp, wantErr, http.StatusBadRequest)
+
+			w = newRequest("?" + suffix + "=" + strconv.Itoa(vmax))
+			resp = w.Result()
+			checkStatus(t, resp, http.StatusOK)
+		})
+	}
+
+	t.Run("limit", func(t *testing.T) {
+		t.Parallel()
+		checkValidate(
+			t, "index=0&sort=0&limit", 1, 100,
+			"limit must be an integer between 1 and 100",
+		)
+	})
+
+	t.Run("index", func(t *testing.T) {
+		t.Parallel()
+		checkValidate(
+			t, "limit=1&sort=0&index", 0, rosa.Native().Count()-1,
+			"index must be an integer between 0 and "+strconv.Itoa(rosa.Native().Count()-1),
+		)
+	})
+
+	t.Run("sort", func(t *testing.T) {
+		t.Parallel()
+		checkValidate(
+			t, "index=0&limit=1&sort", 0, int(sortOrderEnd),
+			"sort must be an integer between 0 and "+strconv.Itoa(int(sortOrderEnd)),
+		)
+	})
+}

cmd/mbf/internal/pkgserver/index.go

@@ -0,0 +1,108 @@
+package pkgserver
+
+import (
+	"cmp"
+	"errors"
+	"slices"
+	"strings"
+
+	"hakurei.app/internal/pkg"
+	"hakurei.app/internal/rosa"
+)
+
+const (
+	declarationAscending = iota
+	declarationDescending
+	nameAscending
+	nameDescending
+	sizeAscending
+	sizeDescending
+
+	sortOrderEnd = iota - 1
+)
+
+// packageIndex refers to metadata by name and various sort orders.
+type packageIndex struct {
+	sorts  [sortOrderEnd + 1][]*metadata
+	names  map[string]*metadata
+	search searchCache
+	// Taken from [rosa.Report] if available.
+	handleAccess func(*error) func()
+}
+
+// metadata holds [rosa.Metadata] extended with additional information.
+type metadata struct {
+	handle rosa.ArtifactH
+	*rosa.Artifact
+
+	// Populated via [rosa.Toolchain.Version], [rosa.Unversioned] is equivalent
+	// to the zero value. Otherwise, the zero value is invalid.
+	Version string `json:"version,omitempty"`
+	// Output data size, available if present in report.
+	Size int64 `json:"size,omitempty"`
+	// Whether the underlying [pkg.Artifact] is present in the report.
+	HasReport bool `json:"report"`
+
+	// Ident string encoded ahead of time.
+	ids string
+	// Backed by [rosa.Report], access must be prepared by HandleAccess.
+	status []byte
+}
+
+// populate deterministically populates packageIndex, optionally with a report.
+func (index *packageIndex) populate(report *rosa.Report) (err error) {
+	if report != nil {
+		defer report.HandleAccess(&err)()
+		index.handleAccess = report.HandleAccess
+	}
+
+	handles := rosa.Native().Collect()
+	work := make([]*metadata, len(handles))
+	index.names = make(map[string]*metadata)
+	ir := pkg.NewIR()
+	for i, handle := range handles {
+		a, version := rosa.Native().Std().MustLoad(handle)
+		m := metadata{
+			handle: handle,
+
+			Artifact: rosa.Native().MustGet(handle),
+			Version:  version,
+		}
+		if m.Version == "" {
+			return errors.New("invalid version from " + m.Name)
+		}
+		if m.Version == rosa.Unversioned {
+			m.Version = ""
+		}
+
+		if report != nil {
+			id := ir.Ident(a)
+			m.ids = pkg.Encode(id.Value())
+			m.status, m.Size = report.ArtifactOf(id)
+			m.HasReport = m.Size >= 0
+		}
+
+		work[i] = &m
+		index.names[m.Name] = &m
+	}
+
+	index.sorts[declarationAscending] = work
+	index.sorts[declarationDescending] = slices.Clone(work)
+	slices.Reverse(index.sorts[declarationDescending][:])
+
+	index.sorts[nameAscending] = slices.Clone(work)
+	slices.SortFunc(index.sorts[nameAscending][:], func(a, b *metadata) int {
+		return strings.Compare(a.Name, b.Name)
+	})
+	index.sorts[nameDescending] = slices.Clone(index.sorts[nameAscending])
+	slices.Reverse(index.sorts[nameDescending][:])
+
+	index.sorts[sizeAscending] = slices.Clone(work)
+	slices.SortFunc(index.sorts[sizeAscending][:], func(a, b *metadata) int {
+		return cmp.Compare(a.Size, b.Size)
+	})
+	index.sorts[sizeDescending] = slices.Clone(index.sorts[sizeAscending])
+	slices.Reverse(index.sorts[sizeDescending][:])
+
+	return
+}

cmd/mbf/internal/pkgserver/index_test.go

@@ -0,0 +1,96 @@
+package pkgserver
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+	"reflect"
+	"testing"
+)
+
+// newIndex returns the address of a newly populated packageIndex.
+func newIndex(t *testing.T) *packageIndex {
+	t.Helper()
+
+	var index packageIndex
+	if err := index.populate(nil); err != nil {
+		t.Fatalf("populate: error = %v", err)
+	}
+	return &index
+}
+
+// checkStatus checks response status code.
+func checkStatus(t *testing.T, resp *http.Response, want int) {
+	t.Helper()
+
+	if resp.StatusCode != want {
+		t.Errorf(
+			"StatusCode: %s, want %s",
+			http.StatusText(resp.StatusCode),
+			http.StatusText(want),
+		)
+	}
+}
+
+// checkHeader checks the value of a header entry.
+func checkHeader(t *testing.T, h http.Header, key, want string) {
+	t.Helper()
+
+	if got := h.Get(key); got != want {
+		t.Errorf("%s: %q, want %q", key, got, want)
+	}
+}
+
+// checkAPIHeader checks common entries set for API endpoints.
+func checkAPIHeader(t *testing.T, h http.Header) {
+	t.Helper()
+
+	checkHeader(t, h, "Content-Type", "application/json; charset=utf-8")
+	checkHeader(t, h, "Cache-Control", "no-cache, no-store, must-revalidate")
+	checkHeader(t, h, "Pragma", "no-cache")
+	checkHeader(t, h, "Expires", "0")
+}
+
+// checkPayloadFunc checks the JSON response of an API endpoint by passing it to f.
+func checkPayloadFunc[T any](
+	t *testing.T,
+	resp *http.Response,
+	f func(got *T) bool,
+) {
+	t.Helper()
+
+	var got T
+	r := io.Reader(resp.Body)
+	if testing.Verbose() {
+		var buf bytes.Buffer
+		r = io.TeeReader(r, &buf)
+		defer func() { t.Helper(); t.Log(buf.String()) }()
+	}
+	if err := json.NewDecoder(r).Decode(&got); err != nil {
+		t.Fatalf("Decode: error = %v", err)
+	}
+
+	if !f(&got) {
+		t.Errorf("Body: %#v", got)
+	}
+}
+
+// checkPayload checks the JSON response of an API endpoint.
+func checkPayload[T any](t *testing.T, resp *http.Response, want T) {
+	t.Helper()
+
+	checkPayloadFunc(t, resp, func(got *T) bool {
+		return reflect.DeepEqual(got, &want)
+	})
+}
+
+func checkError(t *testing.T, resp *http.Response, error string, code int) {
+	t.Helper()
+
+	checkStatus(t, resp, code)
+	if got, _ := io.ReadAll(resp.Body); string(got) != fmt.Sprintln(error) {
+		t.Errorf("Body: %q, want %q", string(got), error)
+	}
+}

cmd/mbf/internal/pkgserver/search.go

@@ -0,0 +1,81 @@
+package pkgserver
+
+import (
+	"cmp"
+	"maps"
+	"regexp"
+	"slices"
+	"time"
+)
+
+type searchCache map[string]searchCacheEntry
+type searchResult struct {
+	NameIndices [][]int `json:"name_matches"`
+	DescIndices [][]int `json:"desc_matches,omitempty"`
+	Score       float64 `json:"score"`
+	*metadata
+}
+type searchCacheEntry struct {
+	query   string
+	results []searchResult
+	expiry  time.Time
+}
+
+func (index *packageIndex) performSearchQuery(limit int, i int, search string, desc bool) (int, []searchResult, error) {
+	query := search
+	if desc {
+		query += ";withDesc"
+	}
+	entry, ok := index.search[query]
+	if ok && len(entry.results) > 0 {
+		return len(entry.results), entry.results[min(i, len(entry.results)-1):min(i+limit, len(entry.results))], nil
+	}
+
+	regex, err := regexp.Compile(search)
+	if err != nil {
+		return 0, make([]searchResult, 0), err
+	}
+	res := make([]searchResult, 0)
+	for p := range maps.Values(index.names) {
+		nameIndices := regex.FindAllIndex([]byte(p.Name), -1)
+		var descIndices [][]int = nil
+		if desc {
+			descIndices = regex.FindAllIndex([]byte(p.Description), -1)
+		}
+		if nameIndices == nil && descIndices == nil {
+			continue
+		}
+		score := float64(indexsum(nameIndices)) / (float64(len(nameIndices)) + 1)
+		if desc {
+			score += float64(indexsum(descIndices)) / (float64(len(descIndices)) + 1) / 10.0
+		}
+		res = append(res, searchResult{
+			NameIndices: nameIndices,
+			DescIndices: descIndices,
+			Score:       score,
+			metadata:    p,
+		})
+	}
+	slices.SortFunc(res[:], func(a, b searchResult) int { return -cmp.Compare(a.Score, b.Score) })
+	expiry := time.Now().Add(1 * time.Minute)
+	entry = searchCacheEntry{
+		query:   search,
+		results: res,
+		expiry:  expiry,
+	}
+	index.search[query] = entry
+
+	return len(res), res[i:min(i+limit, len(entry.results))], nil
+}
+func (s *searchCache) clean() {
+	maps.DeleteFunc(*s, func(_ string, v searchCacheEntry) bool {
+		return v.expiry.Before(time.Now())
+	})
+}
+func indexsum(in [][]int) int {
+	sum := 0
+	for i := 0; i < len(in); i++ {
+		sum += in[i][1] - in[i][0]
+	}
+	return sum
+}

cmd/mbf/internal/pkgserver/ui/all_tests.ts

@@ -0,0 +1,2 @@
+// Import all test files to register their test suites.
+import "./index_test.js";

cmd/mbf/internal/pkgserver/ui/index.html

@@ -0,0 +1,58 @@
+<!DOCTYPE html>
+<html lang="en">
+<head>
+    <meta charset="UTF-8">
+    <meta name="viewport" content="width=device-width, initial-scale=1.0">
+    <link rel="stylesheet" href="style.css">
+    <link rel="icon" href="https://hakurei.app/favicon.ico"/>
+    <title>Rosa OS Packages</title>
+    <script src="index.js"></script>
+</head>
+<body>
+<h1>Rosa OS Packages</h1>
+<div class="top-controls" id="top-controls-regular">
+    <p>Showing entries <span id="entry-counter"></span>.</p>
+    <span id="search-bar">
+        <label for="search">Search: </label>
+        <input type="text" name="search" id="search"/>
+        <button onclick="doSearch()">Find</button>
+        <label for="include-desc">Include descriptions: </label>
+        <input type="checkbox" name="include-desc" id="include-desc" checked/>
+    </span>
+    <div><label for="count">Entries per page: </label><select name="count" id="count">
+        <option value="10">10</option>
+        <option value="20">20</option>
+        <option value="30">30</option>
+        <option value="50">50</option>
+    </select></div>
+    <div><label for="sort">Sort by: </label><select name="sort" id="sort">
+        <option value="0">Definition (ascending)</option>
+        <option value="1">Definition (descending)</option>
+        <option value="2">Name (ascending)</option>
+        <option value="3">Name (descending)</option>
+        <option value="4">Size (ascending)</option>
+        <option value="5">Size (descending)</option>
+    </select></div>
+</div>
+<div class="top-controls" id="search-top-controls" hidden>
+    <p>Showing search results <span id="search-entry-counter"></span> for query "<span id="search-query"></span>".</p>
+    <button onclick="exitSearch()">Back</button>
+    <div><label for="search-count">Entries per page: </label><select name="search-count" id="search-count">
+        <option value="10">10</option>
+        <option value="20">20</option>
+        <option value="30">30</option>
+        <option value="50">50</option>
+    </select></div>
+    <p>Sorted by best match</p>
+</div>
+<div class="page-controls"><a href="javascript:prevPage()">&laquo; Previous</a> <input type="text" class="page-number" value="1"/> <a href="javascript:nextPage()">Next &raquo;</a></div>
+<table id="pkg-list">
+    <tr><td>Loading...</td></tr>
+</table>
+<div class="page-controls"><a href="javascript:prevPage()">&laquo; Previous</a> <input type="text" class="page-number" value="1"/> <a href="javascript:nextPage()">Next &raquo;</a></div>
+<footer>
+    <p>&copy;<a href="https://hakurei.app/">Hakurei</a> (<span id="hakurei-version">unknown</span>). Licensed under the MIT license.</p>
+</footer>
+<script>main();</script>
+</body>
+</html>

cmd/mbf/internal/pkgserver/ui/index.ts

@@ -0,0 +1,331 @@
+interface PackageIndexEntry {
+    name: string
+    size?: number
+    description?: string
+    website?: string
+    version?: string
+    report?: boolean
+}
+
+function entryToHTML(entry: PackageIndexEntry | SearchResult): HTMLTableRowElement {
+    let v = entry.version != null ? `<span>${escapeHtml(entry.version)}</span>` : ""
+    let s = entry.size != null && entry.size > 0 ? `<p>Size: ${toByteSizeString(entry.size)} (${entry.size})</p>` : ""
+    let n: string
+    let d: string
+    if ('name_matches' in entry) {
+        n = `<h2>${nameMatches(entry as SearchResult)} ${v}</h2>`
+    } else {
+        n = `<h2>${escapeHtml(entry.name)} ${v}</h2>`
+    }
+    if ('desc_matches' in entry && STATE.getIncludeDescriptions()) {
+        d = descMatches(entry as SearchResult)
+    } else {
+        d = (entry as PackageIndexEntry).description != null ? `<p>${escapeHtml((entry as PackageIndexEntry).description)}</p>` : ""
+    }
+    let w = entry.website != null ? `<a href="${encodeURI(entry.website)}">Website</a>` : ""
+    let r = entry.report ? `Log (<a href=\"${encodeURI('/api/v1/status/' + entry.name)}\">View</a> | <a href=\"${encodeURI('/status/' + entry.name)}\">Download</a>)` : ""
+    let row = <HTMLTableRowElement>(document.createElement('tr'))
+    row.innerHTML = `<td>
+            ${n}
+            ${d}
+            ${s}
+            ${w}
+            ${r}
+        </td>`
+    return row
+}
+
+function nameMatches(sr: SearchResult): string {
+    return markMatches(sr.name, sr.name_matches)
+}
+
+function descMatches(sr: SearchResult): string {
+    return markMatches(sr.description!, sr.desc_matches)
+}
+
+function markMatches(str: string, indices: [number, number][]): string {
+    if (indices == null) {
+        return str
+    }
+    let out: string = ""
+    let j = 0
+    for (let i = 0; i < str.length; i++) {
+        if (j < indices.length) {
+            if (i === indices[j][0]) {
+                out += `<mark>${escapeHtmlChar(str[i])}`
+                continue
+            }
+            if (i === indices[j][1]) {
+                out += `</mark>${escapeHtmlChar(str[i])}`
+                j++
+                continue
+            }
+        }
+        out += escapeHtmlChar(str[i])
+    }
+    if (indices[j] !== undefined) {
+        out += "</mark>"
+    }
+    return out
+}
+
+function toByteSizeString(bytes: number): string {
+    if (bytes == null) return `unspecified`
+    if (bytes < 1024) return `${bytes}B`
+    if (bytes < Math.pow(1024, 2)) return `${(bytes / 1024).toFixed(2)}kiB`
+    if (bytes < Math.pow(1024, 3)) return `${(bytes / Math.pow(1024, 2)).toFixed(2)}MiB`
+    if (bytes < Math.pow(1024, 4)) return `${(bytes / Math.pow(1024, 3)).toFixed(2)}GiB`
+    if (bytes < Math.pow(1024, 5)) return `${(bytes / Math.pow(1024, 4)).toFixed(2)}TiB`
+    return "not only is it big, it's large"
+}
+
+const API_VERSION = 1
+const ENDPOINT = `/api/v${API_VERSION}`
+
+interface InfoPayload {
+    count?: number
+    hakurei_version?: string
+}
+
+async function infoRequest(): Promise<InfoPayload> {
+    const res = await fetch(`${ENDPOINT}/info`)
+    const payload = await res.json()
+    return payload as InfoPayload
+}
+
+interface GetPayload {
+    values?: PackageIndexEntry[]
+}
+
+enum SortOrders {
+    DeclarationAscending,
+    DeclarationDescending,
+    NameAscending,
+    NameDescending
+}
+
+async function getRequest(limit: number, index: number, sort: SortOrders): Promise<GetPayload> {
+    const res = await fetch(`${ENDPOINT}/get?limit=${limit}&index=${index}&sort=${sort.valueOf()}`)
+    const payload = await res.json()
+    return payload as GetPayload
+}
+
+interface SearchResult extends PackageIndexEntry {
+    name_matches: [number, number][]
+    desc_matches: [number, number][]
+    score: number
+}
+
+interface SearchPayload {
+    count?: number
+    values?: SearchResult[]
+}
+
+async function searchRequest(limit: number, index: number, search: string, desc: boolean): Promise<SearchPayload> {
+    const res = await fetch(`${ENDPOINT}/search?limit=${limit}&index=${index}&search=${encodeURIComponent(search)}&desc=${desc}`)
+    if (!res.ok) {
+        exitSearch()
+        alert("invalid search query!")
+        return Promise.reject(res.statusText)
+    }
+    const payload = await res.json()
+    return payload as SearchPayload
+}
+
+class State {
+    entriesPerPage: number = 10
+    entryIndex: number = 0
+    maxTotal: number = 0
+    maxEntries: number = 0
+    sort: SortOrders = SortOrders.DeclarationAscending
+    search: boolean = false
+
+    getEntriesPerPage(): number {
+        return this.entriesPerPage
+    }
+
+    setEntriesPerPage(entriesPerPage: number) {
+        this.entriesPerPage = entriesPerPage
+        this.setEntryIndex(Math.floor(this.getEntryIndex() / entriesPerPage) * entriesPerPage)
+    }
+
+    getEntryIndex(): number {
+        return this.entryIndex
+    }
+
+    setEntryIndex(entryIndex: number) {
+        this.entryIndex = entryIndex
+        this.updatePage()
+        this.updateRange()
+        this.updateListings()
+    }
+
+    getMaxTotal(): number {
+        return this.maxTotal
+    }
+
+    setMaxTotal(max: number) {
+        this.maxTotal = max
+    }
+
+    getSortOrder(): SortOrders {
+        return this.sort
+    }
+
+    setSortOrder(sortOrder: SortOrders) {
+        this.sort = sortOrder
+        this.setEntryIndex(0)
+    }
+
+    updatePage() {
+        let page = Math.ceil(((this.getEntryIndex() + this.getEntriesPerPage()) - 1) / this.getEntriesPerPage())
+        for (let e of document.getElementsByClassName("page-number")) {
+            (e as HTMLInputElement).value = String(page)
+        }
+    }
+
+    updateRange() {
+        let max = Math.min(this.getEntryIndex() + this.getEntriesPerPage(), this.getMaxTotal())
+        document.getElementById("entry-counter")!.textContent = `${this.getEntryIndex() + 1}-${max} of ${this.getMaxTotal()}`
+        if (this.search) {
+            document.getElementById("search-entry-counter")!.textContent = `${this.getEntryIndex() + 1}-${max} of ${this.maxTotal}/${this.maxEntries}`
+            document.getElementById("search-query")!.innerHTML = `<code>${escapeHtml(this.getSearchQuery())}</code>`
+        }
+    }
+
+    getSearchQuery(): string {
+        let queryString = document.getElementById("search")!;
+        return (queryString as HTMLInputElement).value
+    }
+
+    getIncludeDescriptions(): boolean {
+        let includeDesc = document.getElementById("include-desc")!;
+        return (includeDesc as HTMLInputElement).checked
+    }
+
+    updateListings() {
+        if (this.search) {
+            searchRequest(this.getEntriesPerPage(), this.getEntryIndex(), this.getSearchQuery(), this.getIncludeDescriptions())
+                .then(res => {
+                    let table = document.getElementById("pkg-list")!
+                    table.innerHTML = ''
+                    for (let row of res.values!) {
+                        table.appendChild(entryToHTML(row))
+                    }
+                    STATE.maxTotal = res.count!
+                    STATE.updateRange()
+                    if(res.count! < 1) {
+                        exitSearch()
+                        alert("no results found!")
+                    }
+                })
+        } else {
+            getRequest(this.getEntriesPerPage(), this.getEntryIndex(), this.getSortOrder())
+                .then(res => {
+                    let table = document.getElementById("pkg-list")!
+                    table.innerHTML = ''
+                    for (let row of res.values!) {
+                        table.appendChild(entryToHTML(row))
+                    }
+                })
+        }
+    }
+}
+
+let STATE: State
+
+
+function lastPageIndex(): number {
+    return Math.floor(STATE.getMaxTotal() / STATE.getEntriesPerPage()) * STATE.getEntriesPerPage()
+}
+
+function setPage(page: number) {
+    STATE.setEntryIndex(Math.max(0, Math.min(STATE.getEntriesPerPage() * (page - 1), lastPageIndex())))
+}
+
+
+function escapeHtml(str?: string): string {
+    let out: string = ''
+    if (str == undefined) return ""
+    for (let i = 0; i < str.length; i++) {
+        out += escapeHtmlChar(str[i])
+    }
+    return out
+}
+
+function escapeHtmlChar(char: string): string {
+    if (char.length != 1) return char
+    switch (char[0]) {
+        case '&':
+            return "&amp;"
+        case '<':
+            return "&lt;"
+        case '>':
+            return "&gt;"
+        case '"':
+            return "&quot;"
+        case "'":
+            return "&apos;"
+        default:
+            return char
+    }
+}
+
+function firstPage() {
+    STATE.setEntryIndex(0)
+}
+
+function prevPage() {
+    let index = STATE.getEntryIndex()
+    STATE.setEntryIndex(Math.max(0, index - STATE.getEntriesPerPage()))
+}
+
+function lastPage() {
+    STATE.setEntryIndex(lastPageIndex())
+}
+
+function nextPage() {
+    let index = STATE.getEntryIndex()
+    STATE.setEntryIndex(Math.min(lastPageIndex(), index + STATE.getEntriesPerPage()))
+}
+
+function doSearch() {
+    document.getElementById("top-controls-regular")!.toggleAttribute("hidden");
+    document.getElementById("search-top-controls")!.toggleAttribute("hidden");
+    STATE.search = true;
+    STATE.setEntryIndex(0);
+}
+
+function exitSearch() {
+    document.getElementById("top-controls-regular")!.toggleAttribute("hidden");
+    document.getElementById("search-top-controls")!.toggleAttribute("hidden");
+    STATE.search = false;
+    STATE.setMaxTotal(STATE.maxEntries)
+    STATE.setEntryIndex(0)
+}
+
+function main() {
+    STATE = new State()
+    infoRequest()
+        .then(res => {
+            STATE.maxEntries = res.count!
+            STATE.setMaxTotal(STATE.maxEntries)
+            document.getElementById("hakurei-version")!.textContent = res.hakurei_version!
+            STATE.updateRange()
+            STATE.updateListings()
+        })
+    for (let e of document.getElementsByClassName("page-number")) {
+        e.addEventListener("change", (_) => {
+            setPage(parseInt((e as HTMLInputElement).value))
+        })
+    }
+    document.getElementById("count")?.addEventListener("change", (event) => {
+        STATE.setEntriesPerPage(parseInt((event.target as HTMLSelectElement).value))
+    })
+    document.getElementById("sort")?.addEventListener("change", (event) => {
+        STATE.setSortOrder(parseInt((event.target as HTMLSelectElement).value))
+    })
+    document.getElementById("search")?.addEventListener("keyup", (event) => {
+        if (event.key === 'Enter') doSearch()
+    })
+}

cmd/mbf/internal/pkgserver/ui/index_test.ts

@@ -0,0 +1,2 @@
+import { suite, test } from "./jstest/jstest.js";
+import "./index.js";

cmd/mbf/internal/pkgserver/ui/jstest/cli.ts

@@ -0,0 +1,48 @@
+#!/usr/bin/env node
+
+// Many editors have terminal emulators built in, so running tests with NodeJS
+// provides faster iteration, especially for those acclimated to test-driven
+// development.
+
+import "../all_tests.js";
+import { StreamReporter, GLOBAL_REGISTRAR } from "./jstest.js";
+
+// TypeScript doesn't like process and Deno as their type definitions aren't
+// installed, but doesn't seem to complain if they're accessed through
+// globalThis.
+const process: any = (globalThis as any).process;
+const Deno: any = (globalThis as any).Deno;
+
+function getArgs(): string[] {
+    if (process) {
+        const [runtime, program, ...args] = process.argv;
+        return args;
+    }
+    if (Deno) return Deno.args;
+    return [];
+}
+
+function exit(code?: number): never {
+    if (Deno) Deno.exit(code);
+    if (process) process.exit(code);
+    throw `exited with code ${code ?? 0}`;
+}
+
+const args = getArgs();
+let verbose = false;
+if (args.length > 1) {
+    console.error("Too many arguments");
+    exit(1);
+}
+if (args.length === 1) {
+    if (args[0] === "-v" || args[0] === "--verbose" || args[0] === "-verbose") {
+        verbose = true;
+    } else if (args[0] !== "--") {
+        console.error(`Unknown argument '${args[0]}'`);
+        exit(1);
+    }
+}
+
+let reporter = new StreamReporter({ writeln: console.log }, verbose);
+GLOBAL_REGISTRAR.run(reporter);
+exit(reporter.succeeded() ? 0 : 1);

cmd/mbf/internal/pkgserver/ui/jstest/failure-closed.svg

@@ -0,0 +1,13 @@
+<?xml version="1.0"?>
+<!-- See failure-open.svg for an explanation of the view box dimensions. -->
+<svg xmlns="http://www.w3.org/2000/svg" width="20" viewBox="-20,-20 160 130">
+    <!-- This triangle should match success-closed.svg, fill and stroke color notwithstanding. -->
+    <polygon points="0,0 100,50 0,100" fill="red" stroke="red" stroke-width="15" stroke-linejoin="round"/>
+    <!--
+     ! y-coordinates go before x-coordinates here to highlight the difference
+     ! (or, lack thereof) between these numbers and the ones in failure-open.svg;
+     ! try a textual diff. Make sure to keep the numbers in sync!
+     -->
+    <line y1="30" x1="10" y2="70" x2="50" stroke="white" stroke-width="16"/>
+    <line y1="30" x1="50" y2="70" x2="10" stroke="white" stroke-width="16"/>
+</svg>

cmd/mbf/internal/pkgserver/ui/jstest/failure-open.svg

@@ -0,0 +1,35 @@
+<?xml version="1.0"?>
+<!--
+ ! This view box is a bit weird: the strokes assume they're working in a view
+ ! box that spans from the (0,0) to (100,100), and indeed that is convenient
+ ! conceptualizing the strokes, but the stroke itself has a considerable width
+ ! that gets clipped by restrictive view box dimensions. Hence, the view is
+ ! shifted from (0,0)–(100,100) to (-20,-20)–(120,120), to make room for the
+ ! clipped stroke, while leaving behind an illusion of working in a view box
+ ! spanning from (0,0) to (100,100).
+ !
+ ! However, the resulting SVG is too close to the summary text, and CSS
+ ! properties to add padding do not seem to work with `content:` (likely because
+ ! they're anonymous replaced elements); thus, the width of the view is
+ ! increased considerably to provide padding in the SVG itself, while leaving
+ ! the strokes oblivious.
+ !
+ ! It gets worse: the summary text isn't vertically aligned with the icon! As
+ ! a flexbox cannot be used in a summary to align the marker with the text, the
+ ! simplest and most effective solution is to reduce the height of the view box
+ ! from 140 to 130, thereby removing some of the bottom padding present.
+ !
+ ! All six SVGs use the same view box (and indeed, they refer to this comment)
+ ! so that they all appear to be the same size and position relative to each
+ ! other on the DOM—indeed, the view box dimensions, alongside the width,
+ ! directly control their placement on the DOM.
+ !
+ ! TL;DR: CSS is janky, overflow is weird, and SVG is awesome!
+ -->
+<svg xmlns="http://www.w3.org/2000/svg" width="20" viewBox="-20,-20 160 130">
+    <!-- This triangle should match success-open.svg, fill and stroke color notwithstanding. -->
+    <polygon points="0,0 100,0 50,100" fill="red" stroke="red" stroke-width="15" stroke-linejoin="round"/>
+    <!-- See the comment in failure-closed.svg before modifying this. -->
+    <line x1="30" y1="10" x2="70" y2="50" stroke="white" stroke-width="16"/>
+    <line x1="30" y1="50" x2="70" y2="10" stroke="white" stroke-width="16"/>
+</svg>

cmd/mbf/internal/pkgserver/ui/jstest/go_test_entrypoint.ts

@@ -0,0 +1,3 @@
+import "../all_tests.js";
+import { GoTestReporter, GLOBAL_REGISTRAR } from "./jstest.js";
+GLOBAL_REGISTRAR.run(new GoTestReporter());

cmd/mbf/internal/pkgserver/ui/jstest/index.html

@@ -0,0 +1,39 @@
+<!doctype html>
+<html lang="en">
+<head>
+    <meta charset="UTF-8">
+    <meta name="viewport" content="width=device-width, initial-scale=1.0">
+    <link rel="stylesheet" href="./style.css">
+    <title>PkgServer Tests</title>
+</head>
+<body>
+<noscript>
+    I hate JavaScript as much as you, but this page runs tests written in
+    JavaScript to test the functionality of code written in JavaScript, so it
+    wouldn't make sense for it to work without JavaScript. <strong>Please turn
+    JavaScript on!</strong>
+</noscript>
+
+<h1>PkgServer Tests</h1>
+
+<main>
+<p id="counters">
+    <span id="success-counter">0</span> succeeded, <span id="failure-counter">0</span>
+    failed<span id="skip-counter-text" hidden>, <span id="skip-counter">0</span> skipped</span>.
+</p>
+
+<p hidden id="success-description">Successful test</p>
+<p hidden id="failure-description">Failed test</p>
+<p hidden id="skip-description">Partially or fully skipped test</p>
+
+<div id="root">
+</div>
+
+<script type="module">
+    import "../all_tests.js";
+    import { DOMReporter, GLOBAL_REGISTRAR } from "./jstest.js";
+    GLOBAL_REGISTRAR.run(new DOMReporter());
+</script>
+</main>
+</body>
+</html>

cmd/mbf/internal/pkgserver/ui/jstest/jstest.ts

@@ -0,0 +1,478 @@
+// =============================================================================
+// DSL
+
+type TestTree = TestGroup | Test;
+type TestGroup = { name: string; children: TestTree[] };
+type Test = { name: string; test: (t: TestController) => void };
+
+// A registrar provides a central location to register test suites.
+export class TestRegistrar {
+    // Note that, while this is equivalent to a new tree node sans a name, the
+    // lack of a name provides the illusion of multiple “top-level” suites,
+    // while still allowing reporters to pick their favorite name—say, “JS
+    // tests”—were they to need to label all suites together.
+    #suites: TestGroup[];
+
+    constructor() {
+        this.#suites = [];
+    }
+
+    suite(name: string, children: TestTree[]) {
+        checkDuplicates(name, children);
+        this.#suites.push({ name, children });
+    }
+
+    run(reporter: Reporter) {
+        reporter.register(this.#suites);
+        for (const suite of this.#suites) {
+            for (const c of suite.children) runTests(reporter, [suite.name], c);
+        }
+        reporter.finalize();
+    }
+}
+
+export let GLOBAL_REGISTRAR = new TestRegistrar();
+
+// Register a suite in the global registrar.
+export function suite(name: string, children: TestTree[]) {
+    GLOBAL_REGISTRAR.suite(name, children);
+}
+
+export function group(name: string, children: TestTree[]): TestTree {
+    checkDuplicates(name, children);
+    return { name, children };
+}
+export const context = group;
+export const describe = group;
+
+export function test(name: string, test: (t: TestController) => void): TestTree {
+    return { name, test };
+}
+
+// While this function could certainly refine the type to a map instead of
+// simply checking for duplicates and discarding that knowledge, these test
+// trees are primarily for flooding—that is, iteration—for which an array is
+// better suited.
+function checkDuplicates(parent: string, names: { name: string }[]) {
+    let seen = new Set<string>();
+    for (const { name } of names) {
+        if (seen.has(name)) {
+            throw new RangeError(`duplicate name '${name}' in '${parent}'`);
+        }
+        seen.add(name);
+    }
+}
+
+export type TestState = "success" | "failure" | "skip";
+
+class AbortSentinel {}
+
+export class TestController {
+    #state: TestState;
+    logs: string[];
+
+    constructor() {
+        this.#state = "success";
+        this.logs = [];
+    }
+
+    getState(): TestState {
+        return this.#state;
+    }
+
+    fail() {
+        this.#state = "failure";
+    }
+
+    failed(): boolean {
+        return this.#state === "failure";
+    }
+
+    failNow(): never {
+        this.fail();
+        throw new AbortSentinel();
+    }
+
+    log(message: string) {
+        this.logs.push(message);
+    }
+
+    error(message: string) {
+        this.log(message);
+        this.fail();
+    }
+
+    fatal(message: string): never {
+        this.log(message);
+        this.failNow();
+    }
+
+    skip(message?: string): never {
+        if (message != null) this.log(message);
+        if (this.#state !== "failure") this.#state = "skip";
+        throw new AbortSentinel();
+    }
+
+    skipped(): boolean {
+        return this.#state === "skip";
+    }
+}
+
+// =============================================================================
+// Execution
+
+export interface TestResult {
+    state: TestState;
+    logs: string[];
+}
+
+function runTests(reporter: Reporter, parents: string[], node: TestTree) {
+    const path = [...parents, node.name];
+    if ("children" in node) {
+        for (const c of node.children) runTests(reporter, path, c);
+        return;
+    }
+    let controller = new TestController();
+    try {
+        node.test(controller);
+    } catch (e) {
+        if (!(e instanceof AbortSentinel)) {
+            controller.error(extractExceptionString(e));
+        }
+    }
+    reporter.update(path, { state: controller.getState(), logs: controller.logs });
+}
+
+function extractExceptionString(e: any): string {
+    // String() instead of .toString() as null and undefined don't have
+    // properties.
+    const s = String(e);
+    if (!(e instanceof Error && e.stack)) return s;
+    // v8 (Chromium, NodeJS) includes the error message, while Firefox and
+    // WebKit do not.
+    if (e.stack.startsWith(s)) return e.stack;
+    return `${s}\n${e.stack}`;
+}
+
+// =============================================================================
+// Reporting
+
+export interface Reporter {
+    // A notable feature—or flaw, to some—of the DSL is that the tree of tests
+    // is statically known, which might greatly aid in implementing a reporter.
+    register(suites: TestGroup[]): void;
+    // While we could simply call a function with a tree representing all
+    // results, which would indeed greatly simplify implementation of reporters,
+    // simply registering a path and allowing the reporter to—either implicitly
+    // or explicitly—construct a tree themselves allows for results to be
+    // *incrementally reported*, instead of a great deal of silence until all
+    // tests finish.
+    update(path: string[], result: TestResult): void;
+    // With just update(), the reporter never knows when all tests have
+    // completed. The simplest possible use for this is to notify the user, but
+    // its intent is actually more tailored to the StreamReporter scenario:
+    // while destructively updated report rendering (as with a tree of DOM nodes
+    // which are mutated) always displays the results in a structured manner
+    // matching that of the tests, “rerendering” or otherwise destructively
+    // updating the rendered output might be infeasible in some paradigms, such
+    // as command-line applications—all existing implementations of such
+    // rendering both mess up the scrollback position and necessarily crop out
+    // some of the data at the bottom (since the top of the tree is forced to be
+    // at the top of the screen, as one cannot unscroll portably). Explicitly
+    // signaling to the reporter that no more results will be received permits
+    // it to simply display live test progress linearly, while building up
+    // a tree and displaying it once it's known the tree is complete.
+    finalize(): void;
+}
+
+// A reporter that diligently reports absolutely nothing. This is essentially
+// a way to “undo” the incremental reporting update() provides, getting back the
+// underlying result tree; this makes it extremely convenient in some cases like
+// testing ourself.
+export class NoOpReporter implements Reporter {
+    suites: TestGroup[];
+    results: ({ path: string[] } & TestResult)[];
+    finalized: boolean;
+
+    constructor() {
+        this.suites = [];
+        this.results = [];
+        this.finalized = false;
+    }
+
+    register(suites: TestGroup[]) {
+        this.suites = suites;
+    }
+
+    update(path: string[], result: TestResult) {
+        this.results.push({ path, ...result });
+    }
+
+    finalize() {
+        this.finalized = true;
+    }
+}
+
+export interface Stream {
+    writeln(s: string): void;
+}
+
+const SEP = " ❯ ";
+
+// A simple reporter that outputs to some stream; suitable for CLIs.
+export class StreamReporter implements Reporter {
+    stream: Stream;
+    verbose: boolean;
+    #successes: ({ path: string[] } & TestResult)[];
+    #failures: ({ path: string[] } & TestResult)[];
+    #skips: ({ path: string[] } & TestResult)[];
+
+    constructor(stream: Stream, verbose: boolean = false) {
+        this.stream = stream;
+        this.verbose = verbose;
+        this.#successes = [];
+        this.#failures = [];
+        this.#skips = [];
+    }
+
+    succeeded(): boolean {
+        return this.#successes.length > 0 && this.#failures.length === 0;
+    }
+
+    // We don't need the structure for reporting.
+    register(suites: TestGroup[]) {}
+
+    update(path: string[], result: TestResult) {
+        if (path.length === 0) throw new RangeError("path is empty");
+        const pathStr = path.join(SEP);
+        switch (result.state) {
+        case "success":
+            this.#successes.push({ path, ...result });
+            // NOTE: emojis are used instead of colored Unicode symbols as
+            // coloring isn't possible through all streams and detecting if
+            // colors should be used is very difficult¹. Furthermore, ensuring
+            // reasonable contrast is retained on every possible theme is
+            // difficult, with reverse video often being the only way (which
+            // also has questionable support across terminal emulators), and the
+            // Unicode characters might be too small to be immediately
+            // noticeable—consider ✓ and ⚠ and ✗. Emojis have an upper hand in
+            // that they're more common than obscure Unicode characters—which
+            // also means you're likely to have an emoji font but not a font for
+            // some weird symbols—and that they're double-width. Finally,
+            // Unicode characters are often very different across fonts; some
+            // fonts make ⚠ filled in, while others have just an outline for the
+            // triangle (which is much harder to comprehend), and the various
+            // crosses like all of x ⨯ × ✕ ✖ ✗ 🗙 🞨 🞩 🞪 🞫 🞬 🞭 🞮 look different
+            // across different fonts, which makes using them for some specific
+            // purpose difficult. Emojis don't have this problem because emoji
+            // vendors try to make them look similar to each other.
+            //
+            // ¹This necessitates checking if the stream is a TTY, checking if
+            //  $TERM is `dumb` when connected to a TTY, checking
+            //  https://no-color.org, https://bixense.com/clicolors, and
+            //  https://force-color.org, checking if setting the
+            //  ENABLE_VIRTUAL_TERMINAL_PROCESSING bit on the TTY works when on
+            //  on Windows, and doing something similar for Cygwin.
+            if (this.verbose) this.stream.writeln(`✅️ ${pathStr}`);
+            break;
+        case "failure":
+            this.#failures.push({ path, ...result });
+            this.stream.writeln(`⚠️ ${pathStr}`);
+            break;
+        case "skip":
+            this.#skips.push({ path, ...result });
+            this.stream.writeln(`⏭️ ${pathStr}`);
+            break;
+        }
+    }
+
+    finalize() {
+        if (this.verbose) this.#displaySection("successes", this.#successes, true);
+        this.#displaySection("failures", this.#failures);
+        this.#displaySection("skips", this.#skips);
+        this.stream.writeln("");
+        this.stream.writeln(
+            `${this.#successes.length} succeeded, ${this.#failures.length} failed` +
+                (this.#skips.length ? `, ${this.#skips.length} skipped` : ""),
+        );
+    }
+
+    #displaySection(name: string, data: ({ path: string[] } & TestResult)[], ignoreEmpty: boolean = false) {
+        if (!data.length) return;
+
+        // Transform [{ path: ["a", "b", "c"] }, { path: ["a", "b", "d"] }] into
+        // { "a ❯ b": ["c", "d"] }. NOTE: intermediate nodes are collapsed as
+        // excessive nesting is difficult to convey clearly in a text-only
+        // environment.
+        let pathMap = new Map<string, ({ name: string } & TestResult)[]>();
+        for (const t of data) {
+            if (t.path.length === 0) throw new RangeError("path is empty");
+            const key = t.path.slice(0, -1).join(SEP);
+            if (!pathMap.has(key)) pathMap.set(key, []);
+            pathMap.get(key)!.push({ name: t.path.at(-1)!, ...t });
+        }
+
+        this.stream.writeln("");
+        this.stream.writeln(name.toUpperCase());
+        this.stream.writeln("=".repeat(name.length));
+
+        for (let [path, tests] of pathMap) {
+            if (ignoreEmpty) tests = tests.filter((t) => t.logs.length);
+            if (tests.length === 0) continue;
+            if (tests.length === 1) {
+                this.#writeOutput(tests[0], path ? `${path}${SEP}` : "", false);
+            } else {
+                this.stream.writeln(path);
+                for (const t of tests) this.#writeOutput(t, "  - ", true);
+            }
+        }
+    }
+
+    #writeOutput(test: { name: string } & TestResult, prefix: string, nested: boolean) {
+        let output = "";
+        if (test.logs.length) {
+            // Individual logs might span multiple lines, so join them together
+            // then split it again.
+            const logStr = test.logs.join("\n");
+            const lines = logStr.split("\n");
+            if (lines.length <= 1) {
+                output = `: ${logStr}`;
+            } else {
+                const padding = nested ? "      " : "  ";
+                output = ":\n" + lines.map((line) => padding + line).join("\n");
+            }
+        }
+        this.stream.writeln(`${prefix}${test.name}${output}`);
+    }
+}
+
+function assertGetElementById(id: string): HTMLElement {
+    let elem = document.getElementById(id);
+    if (elem == null) throw new ReferenceError(`element with ID '${id}' missing from DOM`);
+    return elem;
+}
+
+// A reporter that directly translates a tree of results into a tree of
+// collapsible elements in the DOM.
+export class DOMReporter implements Reporter {
+    // It is very difficult to implement this using the statically known tree,
+    // because Map doesn't handle array keys properly (to store the path), and
+    // it's unknown of there's any way to implement it without writing one's own
+    // data types. Oh well; using the DOM as a data structure might seem hacky
+    // but it does have its benefits, apart from encouraging a tagless final.
+    register(suites: TestGroup[]) {}
+
+    update(path: string[], result: TestResult) {
+        if (path.length === 0) throw new RangeError("path is empty");
+        if (result.state === "skip") {
+            assertGetElementById("skip-counter-text").hidden = false;
+        }
+        const counter = assertGetElementById(`${result.state}-counter`);
+        counter.innerText = (Number(counter.innerText) + 1).toString();
+
+        let parent = assertGetElementById("root");
+        for (const node of path) {
+            let child: HTMLDetailsElement | null = null;
+            let summary: HTMLElement | null = null;
+            let d: Element;
+            outer: for (d of parent.children) {
+                if (!(d instanceof HTMLDetailsElement)) continue;
+                for (const s of d.children) {
+                    if (!(s instanceof HTMLElement)) continue;
+                    if (!(s.tagName === "SUMMARY" && s.innerText === node)) continue;
+                    child = d;
+                    summary = s;
+                    break outer;
+                }
+            }
+            if (!child) {
+                child = document.createElement("details");
+                child.className = "test-node";
+                child.ariaRoleDescription = "test";
+                summary = document.createElement("summary");
+                summary.appendChild(document.createTextNode(node));
+                summary.ariaRoleDescription = "test name";
+                child.appendChild(summary);
+                parent.appendChild(child);
+            }
+            if (!summary) throw new Error("unreachable as assigned above");
+
+            switch (result.state) {
+            case "failure":
+                // Only expand failures, to minimize successes and skips.
+                child.open = true;
+                child.classList.add("failure");
+                child.classList.remove("skip");
+                child.classList.remove("success");
+                // The summary marker does not appear in the AOM, so setting its
+                // alt text is fruitless; label the summary itself instead.
+                summary.setAttribute("aria-labelledby", "failure-description");
+                break;
+            case "skip":
+                if (child.classList.contains("failure")) break;
+                child.classList.add("skip");
+                child.classList.remove("success");
+                summary.setAttribute("aria-labelledby", "skip-description");
+                break;
+            case "success":
+                if (child.classList.contains("failure") || child.classList.contains("skip")) break;
+                child.classList.add("success");
+                summary.setAttribute("aria-labelledby", "success-description");
+                break;
+            }
+
+            parent = child;
+        }
+
+        const p = document.createElement("p");
+        p.classList.add("test-desc");
+        if (result.logs.length) {
+            const pre = document.createElement("pre");
+            pre.appendChild(document.createTextNode(result.logs.join("\n")));
+            p.appendChild(pre);
+        } else {
+            p.classList.add("italic");
+            p.appendChild(document.createTextNode("No output."));
+        }
+        parent.appendChild(p);
+    }
+
+    finalize() {}
+}
+
+interface GoNode {
+    name: string;
+    subtests?: GoNode[];
+}
+
+// Used to display results via `go test`, via some glue code from the Go side.
+// TODO(ophestra): said glue code has to be written.
+export class GoTestReporter implements Reporter {
+    register(suites: TestGroup[]) {
+        console.log(JSON.stringify(suites.map(GoTestReporter.serialize)));
+    }
+
+    // Convert a test tree into the one expected by the Go code.
+    static serialize(node: TestTree): GoNode {
+        return {
+            name: node.name,
+            subtests: "children" in node ? node.children.map(GoTestReporter.serialize) : undefined,
+        };
+    }
+
+    update(path: string[], result: TestResult) {
+        let state: number;
+        switch (result.state) {
+            case "success": state = 0; break;
+            case "failure": state = 1; break;
+            case "skip": state = 2; break;
+        }
+        console.log(JSON.stringify({ path, state, logs: result.logs }));
+    }
+
+    // Unnecessary but convenient on the Go side, so that it doesn't have to
+    // infer this via process exit.
+    finalize() {
+        console.log("null");
+    }
+}

cmd/mbf/internal/pkgserver/ui/jstest/skip-closed.svg

@@ -0,0 +1,21 @@
+<?xml version="1.0"?>
+<!-- See failure-open.svg for an explanation of the view box dimensions. -->
+<svg xmlns="http://www.w3.org/2000/svg" width="20" viewBox="-20,-20 160 130">
+    <!-- This triangle should match success-closed.svg, fill and stroke color notwithstanding. -->
+    <polygon points="0,0 100,50 0,100" fill="blue" stroke="blue" stroke-width="15" stroke-linejoin="round"/>
+    <!--
+     ! This path is extremely similar to the one in skip-open.svg; before
+     ! making minor modifications, diff the two to understand how they should
+     ! remain in sync.
+     -->
+    <path
+        d="M 50,50
+           A 23,23 270,1,1 30,30
+           l -10,20
+           m 10,-20
+           l -20,-10"
+        fill="none"
+        stroke="white"
+        stroke-width="12"
+        stroke-linejoin="round"/>
+</svg>

cmd/mbf/internal/pkgserver/ui/jstest/skip-open.svg

@@ -0,0 +1,21 @@
+<?xml version="1.0"?>
+<!-- See failure-open.svg for an explanation of the view box dimensions. -->
+<svg xmlns="http://www.w3.org/2000/svg" width="20" viewBox="-20,-20 160 130">
+    <!-- This triangle should match success-open.svg, fill and stroke color notwithstanding. -->
+    <polygon points="0,0 100,0 50,100" fill="blue" stroke="blue" stroke-width="15" stroke-linejoin="round"/>
+    <!--
+     ! This path is extremely similar to the one in skip-closed.svg; before
+     ! making minor modifications, diff the two to understand how they should
+     ! remain in sync.
+     -->
+    <path
+        d="M 50,50
+           A 23,23 270,1,1 70,30
+           l 10,-20
+           m -10,20
+           l -20,-10"
+        fill="none"
+        stroke="white"
+        stroke-width="12"
+        stroke-linejoin="round"/>
+</svg>

cmd/mbf/internal/pkgserver/ui/jstest/style.css

@@ -0,0 +1,87 @@
+/*
+ * When updating the theme colors, also update them in success-closed.svg and
+ * success-open.svg!
+ */
+
+:root {
+  --bg: #d3d3d3;
+  --fg: black;
+}
+
+@media (prefers-color-scheme: dark) {
+  :root {
+    --bg: #2c2c2c;
+    --fg: ghostwhite;
+  }
+}
+
+html {
+  background-color: var(--bg);
+  color: var(--fg);
+}
+
+h1, p, summary, noscript {
+  font-family: sans-serif;
+}
+
+noscript {
+  font-size: 16pt;
+}
+
+.root {
+  margin: 1rem 0;
+}
+
+details.test-node {
+  margin-left: 1rem;
+  padding: 0.2rem 0.5rem;
+  border-left: 2px dashed var(--fg);
+  > summary {
+    cursor: pointer;
+  }
+  &.success > summary::marker {
+    /*
+     * WebKit only supports color and font-size properties in ::marker [1], and
+     * its ::-webkit-details-marker only supports hiding the marker entirely
+     * [2], contrary to mdn's example [3]; thus, set a color as a fallback:
+     * while it may not be accessible for colorblind individuals, it's better
+     * than no indication of a test's state for anyone, as that there's no other
+     * way to include an indication in the marker on WebKit.
+     *
+     * [1]: https://developer.mozilla.org/en-US/docs/Web/CSS/Reference/Selectors/::marker#browser_compatibility
+     * [2]: https://developer.mozilla.org/en-US/docs/Web/HTML/Reference/Elements/summary#default_style
+     * [3]: https://developer.mozilla.org/en-US/docs/Web/HTML/Reference/Elements/summary#changing_the_summarys_icon
+     */
+    color: var(--fg);
+    content: url("./success-closed.svg") / "success";
+  }
+  &.success[open] > summary::marker {
+    content: url("./success-open.svg") / "success";
+  }
+  &.failure > summary::marker {
+    color: red;
+    content: url("./failure-closed.svg") / "failure";
+  }
+  &.failure[open] > summary::marker {
+    content: url("./failure-open.svg") / "failure";
+  }
+  &.skip > summary::marker {
+    color: blue;
+    content: url("./skip-closed.svg") / "skip";
+  }
+  &.skip[open] > summary::marker {
+    content: url("./skip-open.svg") / "skip";
+  }
+}
+
+p.test-desc {
+  margin: 0 0 0 1rem;
+  padding: 2px 0;
+  > pre {
+    margin: 0;
+  }
+}
+
+.italic {
+  font-style: italic;
+}

cmd/mbf/internal/pkgserver/ui/jstest/success-closed.svg

@@ -0,0 +1,16 @@
+<?xml version="1.0"?>
+<!-- See failure-open.svg for an explanation of the view box dimensions. -->
+<svg xmlns="http://www.w3.org/2000/svg" width="20" viewBox="-20,-20 160 130">
+    <style>
+    .adaptive-stroke {
+        stroke: black;
+    }
+    @media (prefers-color-scheme: dark) {
+        .adaptive-stroke {
+            stroke: ghostwhite;
+        }
+    }
+    </style>
+    <!-- When updating this triangle, also update the other five SVGs. -->
+    <polygon points="0,0 100,50 0,100" fill="none" class="adaptive-stroke" stroke-width="15" stroke-linejoin="round"/>
+</svg>

cmd/mbf/internal/pkgserver/ui/jstest/success-open.svg

@@ -0,0 +1,16 @@
+<?xml version="1.0"?>
+<!-- See failure-open.svg for an explanation of the view box dimensions. -->
+<svg xmlns="http://www.w3.org/2000/svg" width="20" viewBox="-20,-20 160 130">
+    <style>
+    .adaptive-stroke {
+        stroke: black;
+    }
+    @media (prefers-color-scheme: dark) {
+        .adaptive-stroke {
+            stroke: ghostwhite;
+        }
+    }
+    </style>
+    <!-- When updating this triangle, also update the other five SVGs. -->
+    <polygon points="0,0 100,0 50,100" fill="none" class="adaptive-stroke" stroke-width="15" stroke-linejoin="round"/>
+</svg>

cmd/mbf/internal/pkgserver/ui/style.css

@@ -0,0 +1,21 @@
+.page-number {
+  width: 2em;
+  text-align: center;
+}
+.page-number {
+  width: 2em;
+  text-align: center;
+}
+
+@media (prefers-color-scheme: dark) {
+  html {
+    background-color: #2c2c2c;
+    color: ghostwhite;
+  }
+}
+@media (prefers-color-scheme: light) {
+  html {
+    background-color: #d3d3d3;
+    color: black;
+  }
+}

cmd/mbf/internal/pkgserver/ui/test_ui.go

@@ -0,0 +1,13 @@
+//go:build frontend && frontend_test
+
+package ui
+
+import "embed"
+
+//go:generate tsc -p tsconfig.test.json
+//go:generate cp index.html style.css favicon.ico static
+//go:generate cp jstest/index.html jstest/style.css static/jstest
+//go:generate sh -c "cp jstest/*.svg static/jstest"
+//go:embed static
+var _static embed.FS
+var static = staticFS(_static)

cmd/mbf/internal/pkgserver/ui/tsconfig.json

@@ -0,0 +1,11 @@
+// This file defines the common options for all TypeScript here. This shouldn't
+// be directly used as the project file in builds; see tsconfig.*.json instead,
+// which inherit from this file and essentially define specific build targets.
+{
+  "compilerOptions": {
+    "target": "ES2024",
+    "strict": true,
+    "alwaysStrict": true,
+    "outDir": "static",
+  },
+}

cmd/mbf/internal/pkgserver/ui/tsconfig.test.json

@@ -0,0 +1,5 @@
+// Project file for building pkgserver alongside its tests. test_ui.go uses this
+// as its project file.
+{
+  "extends": "./tsconfig.json",
+}

cmd/mbf/internal/pkgserver/ui/tsconfig.ui.json

@@ -0,0 +1,6 @@
+// Project file for building just the pkgserver UI, with none of the testing
+// stuff attached. ui_full.go uses this as its project file.
+{
+  "extends": "./tsconfig.json",
+  "exclude": ["jstest", "all_tests.ts", "*_test.ts"],
+}

cmd/mbf/internal/pkgserver/ui/ui.go

@@ -0,0 +1,21 @@
+// Package ui holds the static web UI.
+package ui
+
+import (
+	"io/fs"
+	"net/http"
+)
+
+// staticFS is an internal helper to wrap around go:embed's filesystem.
+func staticFS(static fs.FS) fs.FS {
+	if f, err := fs.Sub(static, "static"); err != nil {
+		panic(err)
+	} else {
+		return f
+	}
+}
+
+// Register arranges for mux to serve the embedded frontend.
+func Register(mux *http.ServeMux) {
+	mux.Handle("GET /", http.FileServer(http.FS(static)))
+}

cmd/mbf/internal/pkgserver/ui/ui_full.go

@@ -0,0 +1,11 @@
+//go:build frontend && !frontend_test
+
+package ui
+
+import "embed"
+
+//go:generate tsc -p tsconfig.ui.json
+//go:generate cp index.html style.css static
+//go:embed static
+var _static embed.FS
+var static = staticFS(_static)

cmd/mbf/internal/pkgserver/ui/ui_stub.go

@@ -0,0 +1,7 @@
+//go:build !frontend
+
+package ui
+
+import "testing/fstest"
+
+var static fstest.MapFS

cmd/mbf/main.go

@@ -0,0 +1,902 @@
+// The mbf program is a frontend for [hakurei.app/internal/rosa].
+//
+// This program is not covered by the compatibility promise. The command line
+// interface, available packages and their behaviour, and even the on-disk
+// format, may change at any time.
+//
+// # Name
+//
+// The name mbf stands for maiden's best friend, as a tribute to the DOOM source
+// port of [the same name]. This name is a placeholder and is subject to change.
+//
+// [the same name]: https://www.doomwiki.org/wiki/MBF
+package main
+
+import (
+	"context"
+	"crypto/sha512"
+	"errors"
+	"fmt"
+	"io"
+	"log"
+	"net"
+	"net/http"
+	"os"
+	"os/signal"
+	"path/filepath"
+	"runtime"
+	"strconv"
+	"sync"
+	"sync/atomic"
+	"syscall"
+	"time"
+	"unique"
+
+	"hakurei.app/check"
+	"hakurei.app/command"
+	"hakurei.app/container"
+	"hakurei.app/container/seccomp"
+	"hakurei.app/container/std"
+	"hakurei.app/ext"
+	"hakurei.app/fhs"
+	"hakurei.app/internal/pkg"
+	"hakurei.app/internal/rosa"
+	"hakurei.app/message"
+
+	"hakurei.app/cmd/mbf/internal/pkgserver"
+	"hakurei.app/cmd/mbf/internal/pkgserver/ui"
+)
+
+func main() {
+	container.TryArgv0(nil)
+
+	log.SetFlags(0)
+	log.SetPrefix("mbf: ")
+	msg := message.New(log.Default())
+
+	if os.Geteuid() == 0 {
+		log.Fatal("this program must not run as root")
+	}
+
+	ctx, stop := signal.NotifyContext(context.Background(),
+		syscall.SIGINT, syscall.SIGTERM, syscall.SIGHUP)
+	defer stop()
+
+	var cm cache
+	defer func() { cm.Close() }()
+
+	var (
+		flagQuiet bool
+		flagQEMU  bool
+		flagArch  string
+		flagCheck bool
+		flagLTO   bool
+
+		flagCrossOverride int
+
+		addr net.UnixAddr
+	)
+	c := command.New(os.Stderr, log.Printf, "mbf", func([]string) error {
+		msg.SwapVerbose(!flagQuiet)
+		cm.ctx, cm.msg = ctx, msg
+		cm.base = os.ExpandEnv(cm.base)
+		if cm.base == "" {
+			cm.base = "cache"
+		}
+
+		addr.Net = "unix"
+		addr.Name = os.ExpandEnv(addr.Name)
+		if addr.Name == "" {
+			addr.Name = filepath.Join(cm.base, "daemon")
+		}
+
+		var flags int
+		if !flagCheck {
+			flags |= rosa.OptSkipCheck
+		}
+		if !flagLTO {
+			flags |= rosa.OptLLVMNoLTO
+		}
+		rosa.Native().DropCaches("", flags)
+		cross := flagArch != "" && flagArch != runtime.GOARCH
+		if flagQEMU || cross {
+			cm.qemu, _ = rosa.Native().Std().Load(rosa.QEMU)
+		}
+
+		if cross {
+			if flagCrossOverride != -1 {
+				flags = flagCrossOverride
+			}
+
+			rosa.Native().DropCaches(flagArch, flags)
+			if !rosa.HasStage0() {
+				return pkg.UnsupportedArchError(flagArch)
+			}
+		}
+
+		return nil
+	}).Flag(
+		&flagQuiet,
+		"q", command.BoolFlag(false),
+		"Do not print cure messages",
+	).Flag(
+		&flagQEMU,
+		"register", command.BoolFlag(false),
+		"Enable additional target architectures",
+	).Flag(
+		&flagArch,
+		"arch", command.StringFlag(runtime.GOARCH),
+		"Target architecture",
+	).Flag(
+		&flagLTO,
+		"lto", command.BoolFlag(false),
+		"Enable LTO in stage2 and stage3 LLVM toolchains",
+	).Flag(
+		&flagCheck,
+		"check", command.BoolFlag(true),
+		"Run test suites",
+	).Flag(
+		&flagCrossOverride,
+		"cross-flags", command.IntFlag(-1),
+		"Override non-native target preset flags",
+	).Flag(
+		&cm.verboseInit,
+		"v", command.BoolFlag(false),
+		"Do not suppress verbose output from init",
+	).Flag(
+		&cm.cures,
+		"cures", command.IntFlag(0),
+		"Maximum number of dependencies to cure at any given time",
+	).Flag(
+		&cm.jobs,
+		"jobs", command.IntFlag(0),
+		"Preferred number of jobs to run, when applicable",
+	).Flag(
+		&cm.base,
+		"d", command.StringFlag("$MBF_CACHE_DIR"),
+		"Directory to store cured artifacts",
+	).Flag(
+		&cm.idle,
+		"sched-idle", command.BoolFlag(false),
+		"Set SCHED_IDLE scheduling policy",
+	).Flag(
+		&cm.hostAbstract,
+		"host-abstract", command.BoolFlag(
+			os.Getenv("MBF_HOST_ABSTRACT") != "",
+		),
+		"Do not restrict networked cure containers from connecting to host "+
+			"abstract UNIX sockets",
+	).Flag(
+		&addr.Name,
+		"socket", command.StringFlag("$MBF_DAEMON_SOCKET"),
+		"Pathname of socket to bind to",
+	)
+
+	c.NewCommand(
+		"checksum", "Compute checksum of data read from standard input",
+		func([]string) error {
+			done := make(chan struct{})
+			defer close(done)
+			go func() {
+				select {
+				case <-ctx.Done():
+					os.Exit(1)
+				case <-done:
+					return
+				}
+			}()
+
+			h := sha512.New384()
+			if _, err := io.Copy(h, os.Stdin); err != nil {
+				return err
+			}
+			log.Println(pkg.Encode(pkg.Checksum(h.Sum(nil))))
+			return nil
+		},
+	)
+
+	{
+		var flagShifts int
+		c.NewCommand(
+			"scrub", "Examine the on-disk cache for errors",
+			func(args []string) error {
+				if len(args) > 0 {
+					return errors.New("scrub expects no arguments")
+				}
+				if flagShifts < 0 || flagShifts > 31 {
+					flagShifts = 12
+				}
+				return cm.Do(func(cache *pkg.Cache) error {
+					return cache.Scrub(runtime.NumCPU() << flagShifts)
+				})
+			},
+		).Flag(
+			&flagShifts,
+			"shift", command.IntFlag(12),
+			"Scrub parallelism size exponent, to the power of 2",
+		)
+	}
+
+	{
+		var (
+			flagBind   string
+			flagStatus bool
+			flagReport string
+		)
+		c.NewCommand(
+			"info",
+			"Display out-of-band metadata of an artifact",
+			func(args []string) (err error) {
+				const shutdownTimeout = 15 * time.Second
+
+				var r *rosa.Report
+				if flagReport != "" {
+					if r, err = rosa.OpenReport(flagReport); err != nil {
+						return err
+					}
+					defer func() {
+						if closeErr := r.Close(); err == nil {
+							err = closeErr
+						}
+					}()
+					defer r.HandleAccess(&err)()
+				}
+
+				if flagBind == "" {
+					return commandInfo(&cm, args, os.Stdout, flagStatus, r)
+				}
+
+				var mux http.ServeMux
+				ui.Register(&mux)
+				if err = pkgserver.Register(ctx, &mux, r); err != nil {
+					return
+				}
+
+				server := http.Server{Addr: flagBind, Handler: &mux}
+				go func() {
+					<-ctx.Done()
+					cc, cancel := context.WithTimeout(context.Background(), shutdownTimeout)
+					defer cancel()
+					if _err := server.Shutdown(cc); _err != nil {
+						log.Fatal(_err)
+					}
+				}()
+
+				msg.Verbosef("listening on %q", flagBind)
+				err = server.ListenAndServe()
+				if errors.Is(err, http.ErrServerClosed) {
+					err = nil
+				}
+				return
+			},
+		).Flag(
+			&flagBind,
+			"bind", command.StringFlag(""),
+			"TCP address for the server to listen on",
+		).Flag(
+			&flagStatus,
+			"status", command.BoolFlag(false),
+			"Display cure status if available",
+		).Flag(
+			&flagReport,
+			"report", command.StringFlag(""),
+			"Load cure status from this report file instead of cache",
+		)
+	}
+
+	c.NewCommand(
+		"report",
+		"Generate an artifact cure report for the current cache",
+		func(args []string) (err error) {
+			var w *os.File
+			switch len(args) {
+			case 0:
+				w = os.Stdout
+
+			case 1:
+				if w, err = os.OpenFile(
+					args[0],
+					os.O_CREATE|os.O_EXCL|syscall.O_WRONLY,
+					0400,
+				); err != nil {
+					return
+				}
+				defer func() {
+					closeErr := w.Close()
+					if err == nil {
+						err = closeErr
+					}
+				}()
+
+			default:
+				return errors.New("report requires 1 argument")
+			}
+
+			if ext.Isatty(int(w.Fd())) {
+				return errors.New("output appears to be a terminal")
+			}
+			return cm.Do(func(cache *pkg.Cache) error {
+				return rosa.WriteReport(msg, w, cache)
+			})
+		},
+	)
+
+	{
+		var flagJobs int
+		c.NewCommand("updates", command.UsageInternal, func([]string) error {
+			var (
+				errsMu sync.Mutex
+				errs   []error
+
+				n atomic.Uint64
+			)
+
+			w := make(chan rosa.ArtifactH)
+			var wg sync.WaitGroup
+			for range max(flagJobs, 1) {
+				wg.Go(func() {
+					for p := range w {
+						meta := rosa.Native().MustGet(p)
+						if meta.ID == 0 {
+							continue
+						}
+
+						v, err := meta.GetVersions(ctx)
+						if err != nil {
+							errsMu.Lock()
+							errs = append(errs, err)
+							errsMu.Unlock()
+							continue
+						}
+
+						_, version := rosa.Native().Std().Load(p)
+						if current, latest :=
+							version,
+							meta.GetLatest(v); current != latest {
+
+							n.Add(1)
+							log.Printf("%s %s < %s", meta.Name, current, latest)
+							continue
+						}
+
+						msg.Verbosef("%s is up to date", meta.Name)
+					}
+				})
+			}
+
+		done:
+			for _, p := range rosa.Native().Collect() {
+				select {
+				case w <- p:
+					break
+				case <-ctx.Done():
+					break done
+				}
+			}
+			close(w)
+			wg.Wait()
+
+			if v := n.Load(); v > 0 {
+				errs = append(errs, errors.New(strconv.Itoa(int(v))+
+					" package(s) are out of date"))
+			}
+			return errors.Join(errs...)
+		}).Flag(
+			&flagJobs,
+			"j", command.IntFlag(32),
+			"Maximum number of simultaneous connections",
+		)
+	}
+
+	c.NewCommand(
+		"daemon",
+		"Service artifact IR with Rosa OS extensions",
+		func(args []string) error {
+			ul, err := net.ListenUnix("unix", &addr)
+			if err != nil {
+				return err
+			}
+			log.Printf("listening on pathname socket at %s", addr.Name)
+			return serve(ctx, log.Default(), &cm, ul)
+		},
+	)
+
+	{
+		var (
+			flagGentoo   string
+			flagChecksum string
+
+			flagStage0 bool
+		)
+		c.NewCommand(
+			"stage3",
+			"Check for toolchain 3-stage non-determinism",
+			func(args []string) (err error) {
+				s := rosa.Std
+				if flagGentoo != "" {
+					s -= 3 // magic number to discourage misuse
+
+					var checksum pkg.Checksum
+					if len(flagChecksum) != 0 {
+						if err = pkg.Decode(&checksum, flagChecksum); err != nil {
+							return
+						}
+					}
+					rosa.Native().SetGentooStage3(flagGentoo, checksum)
+				}
+
+				var (
+					pathname *check.Absolute
+					checksum [2]unique.Handle[pkg.Checksum]
+				)
+
+				if err = cm.Do(func(cache *pkg.Cache) (err error) {
+					llvm, _ := rosa.Native().New(s - 2).Load(rosa.LLVM)
+					pathname, _, err = cache.Cure(llvm)
+					return
+				}); err != nil {
+					return
+				}
+				log.Println("stage1:", pathname)
+
+				if err = cm.Do(func(cache *pkg.Cache) (err error) {
+					llvm, _ := rosa.Native().New(s - 1).Load(rosa.LLVM)
+					pathname, checksum[0], err = cache.Cure(llvm)
+					return
+				}); err != nil {
+					return
+				}
+				log.Println("stage2:", pathname)
+				if err = cm.Do(func(cache *pkg.Cache) (err error) {
+					llvm, _ := rosa.Native().New(s).Load(rosa.LLVM)
+					pathname, checksum[1], err = cache.Cure(llvm)
+					return
+				}); err != nil {
+					return
+				}
+				log.Println("stage3:", pathname)
+
+				if checksum[0] != checksum[1] {
+					err = &pkg.ChecksumMismatchError{
+						Got:  checksum[0].Value(),
+						Want: checksum[1].Value(),
+					}
+				} else {
+					log.Println(
+						"stage2 is identical to stage3",
+						"("+pkg.Encode(checksum[0].Value())+")",
+					)
+				}
+
+				if flagStage0 {
+					if err = cm.Do(func(cache *pkg.Cache) (err error) {
+						stage0, _ := rosa.Native().New(s).Load(rosa.Stage0)
+						pathname, _, err = cache.Cure(stage0)
+						return
+					}); err != nil {
+						return
+					}
+					log.Println(pathname)
+				}
+
+				return
+			},
+		).Flag(
+			&flagGentoo,
+			"gentoo", command.StringFlag(""),
+			"Bootstrap from a Gentoo stage3 tarball",
+		).Flag(
+			&flagChecksum,
+			"checksum", command.StringFlag(""),
+			"Checksum of Gentoo stage3 tarball",
+		).Flag(
+			&flagStage0,
+			"stage0", command.BoolFlag(false),
+			"Create bootstrap stage0 tarball",
+		)
+	}
+
+	{
+		var (
+			flagDump    string
+			flagEnter   bool
+			flagExport  string
+			flagRemote  bool
+			flagNoReply bool
+			flagFaults  bool
+			flagPop     bool
+
+			flagBoot bool
+			flagStd  bool
+		)
+		c.NewCommand(
+			"cure",
+			"Cure the named artifact and show its path",
+			func(args []string) error {
+				if len(args) != 1 {
+					return errors.New("cure requires 1 argument")
+				}
+
+				t := rosa.Std
+				if flagBoot {
+					t -= 2
+				} else if flagStd {
+					t -= 1
+				}
+
+				a, _ := rosa.Native().New(t).Load(rosa.ArtifactH(unique.Make(args[0])))
+				if a == nil {
+					return fmt.Errorf("unknown artifact %q", args[0])
+				}
+
+				switch {
+				default:
+					var pathname *check.Absolute
+					err := cm.Do(func(cache *pkg.Cache) (err error) {
+						pathname, _, err = cache.Cure(a)
+						return
+					})
+					if err != nil {
+						return err
+					}
+					log.Println(pathname)
+
+					if flagExport != "" {
+						msg.Verbosef("exporting %s to %s...", args[0], flagExport)
+
+						var f *os.File
+						if f, err = os.OpenFile(
+							flagExport,
+							os.O_WRONLY|os.O_CREATE|os.O_EXCL,
+							0400,
+						); err != nil {
+							return err
+						} else if _, err = pkg.Flatten(
+							os.DirFS(pathname.String()),
+							".",
+							f,
+						); err != nil {
+							_ = f.Close()
+							return err
+						} else if err = f.Close(); err != nil {
+							return err
+						}
+					}
+
+					return nil
+
+				case flagDump != "":
+					f, err := os.OpenFile(
+						flagDump,
+						os.O_WRONLY|os.O_CREATE|os.O_EXCL,
+						0644,
+					)
+					if err != nil {
+						return err
+					}
+
+					if err = pkg.NewIR().EncodeAll(f, a); err != nil {
+						_ = f.Close()
+						return err
+					}
+
+					return f.Close()
+
+				case flagEnter:
+					return cm.Do(func(cache *pkg.Cache) error {
+						return cache.EnterExec(
+							ctx,
+							a,
+							true, os.Stdin, os.Stdout, os.Stderr,
+							rosa.AbsSystem.Append("bin", "mksh"),
+							"sh",
+						)
+					})
+
+				case flagRemote:
+					var flags uint64
+					if flagNoReply {
+						flags |= remoteNoReply
+					}
+					pathname, err := cureRemote(ctx, &addr, a, flags)
+					if !flagNoReply && err == nil {
+						log.Println(pathname)
+					}
+
+					if errors.Is(err, context.Canceled) {
+						cc, cancel := context.WithDeadline(context.Background(), daemonDeadline())
+						defer cancel()
+
+						if _err := cancelRemote(cc, &addr, a, false); _err != nil {
+							log.Println(err)
+						}
+					}
+
+					return err
+
+				case flagFaults:
+					var faults []pkg.Fault
+					if err := cm.Do(func(cache *pkg.Cache) (err error) {
+						faults, err = cache.ReadFaults(a)
+						return
+					}); err != nil {
+						return err
+					}
+
+					for _, fault := range faults {
+						log.Printf("%s: %s ago", fault.String(), time.Since(fault.Time()))
+					}
+					return nil
+
+				case flagPop:
+					var faults []pkg.Fault
+					if err := cm.Do(func(cache *pkg.Cache) (err error) {
+						faults, err = cache.ReadFaults(a)
+						return
+					}); err != nil {
+						return err
+					}
+
+					if len(faults) == 0 {
+						return errors.New("no fault entries found")
+					}
+					fault := faults[len(faults)-1]
+					r, err := fault.Open()
+					if err != nil {
+						return err
+					}
+					if _, err = io.Copy(os.Stdout, r); err != nil {
+						_ = r.Close()
+						return err
+					}
+					fmt.Println()
+					if err = r.Close(); err != nil {
+						return err
+					}
+
+					log.Printf("faulting cure terminated %s ago", time.Since(fault.Time()))
+					return fault.Destroy()
+				}
+			},
+		).Flag(
+			&flagDump,
+			"dump", command.StringFlag(""),
+			"Write IR to specified pathname and terminate",
+		).Flag(
+			&flagExport,
+			"export", command.StringFlag(""),
+			"Export cured artifact to specified pathname",
+		).Flag(
+			&flagEnter,
+			"enter", command.BoolFlag(false),
+			"Enter cure container with an interactive shell",
+		).Flag(
+			&flagRemote,
+			"daemon", command.BoolFlag(false),
+			"Cure artifact on the daemon",
+		).Flag(
+			&flagNoReply,
+			"no-reply", command.BoolFlag(false),
+			"Do not receive a reply from the daemon",
+		).Flag(
+			&flagBoot,
+			"boot", command.BoolFlag(false),
+			"Build on the stage0 toolchain",
+		).Flag(
+			&flagStd,
+			"std", command.BoolFlag(false),
+			"Build on the intermediate toolchain",
+		).Flag(
+			&flagFaults,
+			"faults", command.BoolFlag(false),
+			"Display fault entries of the specified artifact",
+		).Flag(
+			&flagPop,
+			"pop", command.BoolFlag(false),
+			"Display and destroy the most recent fault entry",
+		)
+	}
+
+	c.NewCommand(
+		"clear",
+		"Remove all fault entries from the cache",
+		func([]string) error {
+			return cm.Do(func(*pkg.Cache) error {
+				pathname := filepath.Join(cm.base, "fault")
+				dents, err := os.ReadDir(pathname)
+				if err != nil {
+					return err
+				}
+
+				for _, dent := range dents {
+					msg.Verbosef("destroying entry %s", dent.Name())
+					if err = os.Remove(filepath.Join(pathname, dent.Name())); err != nil {
+						return err
+					}
+				}
+				log.Printf("destroyed %d fault entries", len(dents))
+				return nil
+			})
+		},
+	)
+
+	c.NewCommand(
+		"abort",
+		"Abort all pending cures on the daemon",
+		func([]string) error { return abortRemote(ctx, &addr, false) },
+	)
+
+	{
+		var (
+			flagNet     bool
+			flagSession bool
+
+			flagWithToolchain bool
+		)
+		c.NewCommand(
+			"shell",
+			"Interactive shell in the specified Rosa OS environment",
+			func(args []string) error {
+				handles := make([]rosa.ArtifactH, len(args)+3)
+				for i, arg := range args {
+					handles[i] = rosa.ArtifactH(unique.Make(arg))
+					if rosa.Native().Get(handles[i]) == nil {
+						return fmt.Errorf("unknown artifact %q", arg)
+					}
+				}
+
+				base := rosa.LLVM
+				if !flagWithToolchain {
+					base = rosa.Musl
+				}
+				handles = append(handles,
+					base,
+					rosa.Mksh,
+					rosa.Toybox,
+				)
+
+				root := make(pkg.Collect, 0, 6+len(args))
+				root = rosa.Native().Std().Append(root, handles...)
+
+				if err := cm.Do(func(cache *pkg.Cache) error {
+					_, _, err := cache.Cure(&root)
+					return err
+				}); err == nil {
+					return errors.New("unreachable")
+				} else if !pkg.IsCollected(err) {
+					return err
+				}
+
+				type cureRes struct {
+					pathname *check.Absolute
+					checksum unique.Handle[pkg.Checksum]
+				}
+				cured := make(map[pkg.Artifact]cureRes)
+				for _, a := range root {
+					if err := cm.Do(func(cache *pkg.Cache) error {
+						pathname, checksum, err := cache.Cure(a)
+						if err == nil {
+							cured[a] = cureRes{pathname, checksum}
+						}
+						return err
+					}); err != nil {
+						return err
+					}
+				}
+
+				// explicitly open for direct error-free use from this point
+				if cm.c == nil {
+					if err := cm.open(); err != nil {
+						return err
+					}
+				}
+
+				layers := pkg.PromoteLayers(root, func(a pkg.Artifact) (
+					*check.Absolute,
+					unique.Handle[pkg.Checksum],
+				) {
+					res := cured[a]
+					return res.pathname, res.checksum
+				}, func(i int, d pkg.Artifact) {
+					r := pkg.Encode(cm.c.Ident(d).Value())
+					if s, ok := d.(fmt.Stringer); ok {
+						if name := s.String(); name != "" {
+							r += "-" + name
+						}
+					}
+					msg.Verbosef("promoted layer %d as %s", i, r)
+				})
+
+				z := container.New(ctx, msg)
+				z.WaitDelay = 3 * time.Second
+				z.SeccompPresets = pkg.SeccompPresets
+				z.SeccompFlags |= seccomp.AllowMultiarch
+				z.ParentPerm = 0700
+				z.HostNet = flagNet
+				z.RetainSession = flagSession
+				z.Hostname = "localhost"
+				z.Uid, z.Gid = (1<<10)-1, (1<<10)-1
+				z.Stdin, z.Stdout, z.Stderr = os.Stdin, os.Stdout, os.Stderr
+				z.Quiet = !cm.verboseInit
+				if s, ok := os.LookupEnv("TERM"); ok {
+					z.Env = append(z.Env, "TERM="+s)
+				}
+
+				var tempdir *check.Absolute
+				if s, err := filepath.Abs(os.TempDir()); err != nil {
+					return err
+				} else if tempdir, err = check.NewAbs(s); err != nil {
+					return err
+				}
+
+				z.Dir = fhs.AbsRoot
+				z.Env = []string{
+					"SHELL=/system/bin/mksh",
+					"PATH=/system/bin",
+					"HOME=/",
+				}
+				z.Path = rosa.AbsSystem.Append("bin", "mksh")
+				z.Args = []string{"mksh"}
+				z.
+					OverlayEphemeral(fhs.AbsRoot, layers...).
+					Place(
+						fhs.AbsEtc.Append("hosts"),
+						[]byte("127.0.0.1 localhost\n"),
+					).
+					Place(
+						fhs.AbsEtc.Append("passwd"),
+						[]byte("media_rw:x:1023:1023::/:/system/bin/sh\n"+
+							"nobody:x:65534:65534::/proc/nonexistent:/system/bin/false\n"),
+					).
+					Place(
+						fhs.AbsEtc.Append("group"),
+						[]byte("media_rw:x:1023:\nnobody:x:65534:\n"),
+					).
+					Bind(tempdir, fhs.AbsTmp, std.BindWritable).
+					Proc(fhs.AbsProc).Dev(fhs.AbsDev, true)
+
+				if err := z.Start(); err != nil {
+					return err
+				}
+				if err := z.Serve(); err != nil {
+					return err
+				}
+				return z.Wait()
+			},
+		).Flag(
+			&flagNet,
+			"net", command.BoolFlag(false),
+			"Share host net namespace",
+		).Flag(
+			&flagSession,
+			"session", command.BoolFlag(true),
+			"Retain session",
+		).Flag(
+			&flagWithToolchain,
+			"with-toolchain", command.BoolFlag(false),
+			"Include the stage2 LLVM toolchain",
+		)
+
+	}
+
+	c.Command(
+		"help",
+		"Show this help message",
+		func([]string) error { c.PrintHelp(); return nil },
+	)
+
+	c.MustParse(os.Args[1:], func(err error) {
+		cm.Close()
+		if w, ok := err.(interface{ Unwrap() []error }); !ok {
+			log.Fatal(err)
+		} else {
+			errs := w.Unwrap()
+			for i, e := range errs {
+				if i == len(errs)-1 {
+					log.Fatal(e)
+				}
+				log.Println(e)
+			}
+		}
+	})
+}

cmd/mbf/main_test.go

@@ -0,0 +1,47 @@
+package main
+
+import (
+	"net"
+	"os"
+	"testing"
+
+	"hakurei.app/internal/rosa"
+)
+
+func TestMain(m *testing.M) {
+	rosa.Native().DropCaches("", rosa.OptLLVMNoLTO)
+	os.Exit(m.Run())
+}
+
+func TestCureAll(t *testing.T) {
+	t.Parallel()
+	const env = "ROSA_TEST_DAEMON"
+
+	if !testing.Verbose() {
+		t.Skip("verbose flag not set")
+	}
+
+	pathname, ok := os.LookupEnv(env)
+	if !ok {
+		t.Skip(env + " not set")
+	}
+
+	addr := net.UnixAddr{Net: "unix", Name: pathname}
+	t.Cleanup(func() {
+		if t.Failed() {
+			if err := abortRemote(t.Context(), &addr, false); err != nil {
+				t.Fatal(err)
+			}
+		}
+	})
+
+	for _, handle := range rosa.Native().Collect() {
+		a, _ := rosa.Native().Std().MustLoad(handle)
+		t.Run(rosa.Native().MustGet(handle).Name, func(t *testing.T) {
+			_, err := cureRemote(t.Context(), &addr, a, 0)
+			if err != nil {
+				t.Error(err)
+			}
+		})
+	}
+}

cmd/planterette/app.go

@@ -1,154 +0,0 @@
-package main
-
-import (
-	"encoding/json"
-	"log"
-	"os"
-	"path"
-
-	"hakurei.app/container/seccomp"
-	"hakurei.app/hst"
-	"hakurei.app/system"
-	"hakurei.app/system/dbus"
-)
-
-type appInfo struct {
-	Name    string `json:"name"`
-	Version string `json:"version"`
-
-	// passed through to [hst.Config]
-	ID string `json:"id"`
-	// passed through to [hst.Config]
-	Identity int `json:"identity"`
-	// passed through to [hst.Config]
-	Groups []string `json:"groups,omitempty"`
-	// passed through to [hst.Config]
-	Devel bool `json:"devel,omitempty"`
-	// passed through to [hst.Config]
-	Userns bool `json:"userns,omitempty"`
-	// passed through to [hst.Config]
-	Net bool `json:"net,omitempty"`
-	// passed through to [hst.Config]
-	Device bool `json:"dev,omitempty"`
-	// passed through to [hst.Config]
-	Tty bool `json:"tty,omitempty"`
-	// passed through to [hst.Config]
-	MapRealUID bool `json:"map_real_uid,omitempty"`
-	// passed through to [hst.Config]
-	DirectWayland bool `json:"direct_wayland,omitempty"`
-	// passed through to [hst.Config]
-	SystemBus *dbus.Config `json:"system_bus,omitempty"`
-	// passed through to [hst.Config]
-	SessionBus *dbus.Config `json:"session_bus,omitempty"`
-	// passed through to [hst.Config]
-	Enablements system.Enablement `json:"enablements"`
-
-	// passed through to [hst.Config]
-	Multiarch bool `json:"multiarch,omitempty"`
-	// passed through to [hst.Config]
-	Bluetooth bool `json:"bluetooth,omitempty"`
-
-	// allow gpu access within sandbox
-	GPU bool `json:"gpu"`
-	// store path to nixGL mesa wrappers
-	Mesa string `json:"mesa,omitempty"`
-	// store path to nixGL source
-	NixGL string `json:"nix_gl,omitempty"`
-	// store path to activate-and-exec script
-	Launcher string `json:"launcher"`
-	// store path to /run/current-system
-	CurrentSystem string `json:"current_system"`
-	// store path to home-manager activation package
-	ActivationPackage string `json:"activation_package"`
-}
-
-func (app *appInfo) toFst(pathSet *appPathSet, argv []string, flagDropShell bool) *hst.Config {
-	config := &hst.Config{
-		ID: app.ID,
-
-		Path: argv[0],
-		Args: argv,
-
-		Enablements: app.Enablements,
-
-		SystemBus:     app.SystemBus,
-		SessionBus:    app.SessionBus,
-		DirectWayland: app.DirectWayland,
-
-		Username: "hakurei",
-		Shell:    shellPath,
-		Data:     pathSet.homeDir,
-		Dir:      path.Join("/data/data", app.ID),
-
-		Identity: app.Identity,
-		Groups:   app.Groups,
-
-		Container: &hst.ContainerConfig{
-			Hostname:   formatHostname(app.Name),
-			Devel:      app.Devel,
-			Userns:     app.Userns,
-			Net:        app.Net,
-			Device:     app.Device,
-			Tty:        app.Tty || flagDropShell,
-			MapRealUID: app.MapRealUID,
-			Filesystem: []*hst.FilesystemConfig{
-				{Src: path.Join(pathSet.nixPath, "store"), Dst: "/nix/store", Must: true},
-				{Src: pathSet.metaPath, Dst: path.Join(hst.Tmp, "app"), Must: true},
-				{Src: "/etc/resolv.conf"},
-				{Src: "/sys/block"},
-				{Src: "/sys/bus"},
-				{Src: "/sys/class"},
-				{Src: "/sys/dev"},
-				{Src: "/sys/devices"},
-			},
-			Link: [][2]string{
-				{app.CurrentSystem, "/run/current-system"},
-				{"/run/current-system/sw/bin", "/bin"},
-				{"/run/current-system/sw/bin", "/usr/bin"},
-			},
-			Etc:     path.Join(pathSet.cacheDir, "etc"),
-			AutoEtc: true,
-		},
-		ExtraPerms: []*hst.ExtraPermConfig{
-			{Path: dataHome, Execute: true},
-			{Ensure: true, Path: pathSet.baseDir, Read: true, Write: true, Execute: true},
-		},
-	}
-	if app.Multiarch {
-		config.Container.SeccompFlags |= seccomp.AllowMultiarch
-	}
-	if app.Bluetooth {
-		config.Container.SeccompFlags |= seccomp.AllowBluetooth
-	}
-	return config
-}
-
-func loadAppInfo(name string, beforeFail func()) *appInfo {
-	bundle := new(appInfo)
-	if f, err := os.Open(name); err != nil {
-		beforeFail()
-		log.Fatalf("cannot open bundle: %v", err)
-	} else if err = json.NewDecoder(f).Decode(&bundle); err != nil {
-		beforeFail()
-		log.Fatalf("cannot parse bundle metadata: %v", err)
-	} else if err = f.Close(); err != nil {
-		log.Printf("cannot close bundle metadata: %v", err)
-		// not fatal
-	}
-
-	if bundle.ID == "" {
-		beforeFail()
-		log.Fatal("application identifier must not be empty")
-	}
-
-	return bundle
-}
-
-func formatHostname(name string) string {
-	if h, err := os.Hostname(); err != nil {
-		log.Printf("cannot get hostname: %v", err)
-		return "hakurei-" + name
-	} else {
-		return h + "-" + name
-	}
-}

cmd/planterette/build.nix

@@ -1,251 +0,0 @@
-{
-  nixpkgsFor,
-  system,
-  nixpkgs,
-  home-manager,
-}:
-
-{
-  lib,
-  stdenv,
-  closureInfo,
-  writeScript,
-  runtimeShell,
-  writeText,
-  symlinkJoin,
-  vmTools,
-  runCommand,
-  fetchFromGitHub,
-
-  zstd,
-  nix,
-  sqlite,
-
-  name ? throw "name is required",
-  version ? throw "version is required",
-  pname ? "${name}-${version}",
-  modules ? [ ],
-  nixosModules ? [ ],
-  script ? ''
-    exec "$SHELL" "$@"
-  '',
-
-  id ? name,
-  identity ? throw "identity is required",
-  groups ? [ ],
-  userns ? false,
-  net ? true,
-  dev ? false,
-  no_new_session ? false,
-  map_real_uid ? false,
-  direct_wayland ? false,
-  system_bus ? null,
-  session_bus ? null,
-
-  allow_wayland ? true,
-  allow_x11 ? false,
-  allow_dbus ? true,
-  allow_pulse ? true,
-  gpu ? allow_wayland || allow_x11,
-}:
-
-let
-  inherit (lib) optionals;
-
-  homeManagerConfiguration = home-manager.lib.homeManagerConfiguration {
-    pkgs = nixpkgsFor.${system};
-    modules = modules ++ [
-      {
-        home = {
-          username = "hakurei";
-          homeDirectory = "/data/data/${id}";
-          stateVersion = "22.11";
-        };
-      }
-    ];
-  };
-
-  launcher = writeScript "hakurei-${pname}" ''
-    #!${runtimeShell} -el
-    ${script}
-  '';
-
-  extraNixOSConfig =
-    { pkgs, ... }:
-    {
-      environment = {
-        etc.nixpkgs.source = nixpkgs.outPath;
-        systemPackages = [ pkgs.nix ];
-      };
-
-      imports = nixosModules;
-    };
-  nixos = nixpkgs.lib.nixosSystem {
-    inherit system;
-    modules = [
-      extraNixOSConfig
-      { nix.settings.experimental-features = [ "flakes" ]; }
-      { nix.settings.experimental-features = [ "nix-command" ]; }
-      { boot.isContainer = true; }
-      { system.stateVersion = "22.11"; }
-    ];
-  };
-
-  etc = vmTools.runInLinuxVM (
-    runCommand "etc" { } ''
-      mkdir -p /etc
-      ${nixos.config.system.build.etcActivationCommands}
-
-      # remove unused files
-      rm -rf /etc/sudoers
-
-      mkdir -p $out
-      tar -C /etc -cf "$out/etc.tar" .
-    ''
-  );
-
-  extendSessionDefault = id: ext: {
-    filter = true;
-
-    talk = [ "org.freedesktop.Notifications" ] ++ ext.talk;
-    own =
-      (optionals (id != null) [
-        "${id}.*"
-        "org.mpris.MediaPlayer2.${id}.*"
-      ])
-      ++ ext.own;
-
-    inherit (ext) call broadcast;
-  };
-
-  nixGL = fetchFromGitHub {
-    owner = "nix-community";
-    repo = "nixGL";
-    rev = "310f8e49a149e4c9ea52f1adf70cdc768ec53f8a";
-    hash = "sha256-lnzZQYG0+EXl/6NkGpyIz+FEOc/DSEG57AP1VsdeNrM=";
-  };
-
-  mesaWrappers =
-    let
-      isIntelX86Platform = system == "x86_64-linux";
-      nixGLPackages = import (nixGL + "/default.nix") {
-        pkgs = nixpkgs.legacyPackages.${system};
-        enable32bits = isIntelX86Platform;
-        enableIntelX86Extensions = isIntelX86Platform;
-      };
-    in
-    symlinkJoin {
-      name = "nixGL-mesa";
-      paths = with nixGLPackages; [
-        nixGLIntel
-        nixVulkanIntel
-      ];
-    };
-
-  info = builtins.toJSON {
-    inherit
-      name
-      version
-      id
-      identity
-      launcher
-      groups
-      userns
-      net
-      dev
-      no_new_session
-      map_real_uid
-      direct_wayland
-      system_bus
-      gpu
-      ;
-
-    session_bus =
-      if session_bus != null then
-        (session_bus (extendSessionDefault id))
-      else
-        (extendSessionDefault id {
-          talk = [ ];
-          own = [ ];
-          call = { };
-          broadcast = { };
-        });
-
-    enablements = (if allow_wayland then 1 else 0) + (if allow_x11 then 2 else 0) + (if allow_dbus then 4 else 0) + (if allow_pulse then 8 else 0);
-
-    mesa = if gpu then mesaWrappers else null;
-    nix_gl = if gpu then nixGL else null;
-    current_system = nixos.config.system.build.toplevel;
-    activation_package = homeManagerConfiguration.activationPackage;
-  };
-in
-
-stdenv.mkDerivation {
-  name = "${pname}.pkg";
-  inherit version;
-  __structuredAttrs = true;
-
-  nativeBuildInputs = [
-    zstd
-    nix
-    sqlite
-  ];
-
-  buildCommand = ''
-    NIX_ROOT="$(mktemp -d)"
-    export USER="nobody"
-
-    # create bootstrap store
-    bootstrapClosureInfo="${
-      closureInfo {
-        rootPaths = [
-          nix
-          nixos.config.system.build.toplevel
-        ];
-      }
-    }"
-    echo "copying bootstrap store paths..."
-    mkdir -p "$NIX_ROOT/nix/store"
-    xargs -n 1 -a "$bootstrapClosureInfo/store-paths" cp -at "$NIX_ROOT/nix/store/"
-    NIX_REMOTE="local?root=$NIX_ROOT" nix-store --load-db < "$bootstrapClosureInfo/registration"
-    NIX_REMOTE="local?root=$NIX_ROOT" nix-store --optimise
-    sqlite3 "$NIX_ROOT/nix/var/nix/db/db.sqlite" "UPDATE ValidPaths SET registrationTime = ''${SOURCE_DATE_EPOCH}"
-    chmod -R +r "$NIX_ROOT/nix/var"
-
-    # create binary cache
-    closureInfo="${
-      closureInfo {
-        rootPaths = [
-          homeManagerConfiguration.activationPackage
-          launcher
-        ]
-        ++ optionals gpu [
-          mesaWrappers
-          nixGL
-        ];
-      }
-    }"
-    echo "copying application paths..."
-    TMP_STORE="$(mktemp -d)"
-    mkdir -p "$TMP_STORE/nix/store"
-    xargs -n 1 -a "$closureInfo/store-paths" cp -at "$TMP_STORE/nix/store/"
-    NIX_REMOTE="local?root=$TMP_STORE" nix-store --load-db < "$closureInfo/registration"
-    sqlite3 "$TMP_STORE/nix/var/nix/db/db.sqlite" "UPDATE ValidPaths SET registrationTime = ''${SOURCE_DATE_EPOCH}"
-    NIX_REMOTE="local?root=$TMP_STORE" nix --offline --extra-experimental-features nix-command \
-        --verbose --log-format raw-with-logs \
-        copy --all --no-check-sigs --to \
-        "file://$NIX_ROOT/res?compression=zstd&compression-level=19&parallel-compression=true"
-
-    # package /etc
-    mkdir -p "$NIX_ROOT/etc"
-    tar -C "$NIX_ROOT/etc" -xf "${etc}/etc.tar"
-
-    # write metadata
-    cp "${writeText "bundle.json" info}" "$NIX_ROOT/bundle.json"
-
-    # create an intermediate file to improve zstd performance
-    INTER="$(mktemp)"
-    tar -C "$NIX_ROOT" -cf "$INTER" .
-    zstd -T0 -19 -fo "$out" "$INTER"
-  '';
-}

cmd/planterette/main.go

@@ -1,333 +0,0 @@
-package main
-
-import (
-	"context"
-	"encoding/json"
-	"errors"
-	"log"
-	"os"
-	"os/signal"
-	"path"
-	"syscall"
-
-	"hakurei.app/command"
-	"hakurei.app/hst"
-	"hakurei.app/internal"
-	"hakurei.app/internal/hlog"
-)
-
-const shellPath = "/run/current-system/sw/bin/bash"
-
-var (
-	errSuccess = errors.New("success")
-)
-
-func init() {
-	hlog.Prepare("planterette")
-	if err := os.Setenv("SHELL", shellPath); err != nil {
-		log.Fatalf("cannot set $SHELL: %v", err)
-	}
-}
-
-func main() {
-	if os.Geteuid() == 0 {
-		log.Fatal("this program must not run as root")
-	}
-
-	ctx, stop := signal.NotifyContext(context.Background(),
-		syscall.SIGINT, syscall.SIGTERM)
-	defer stop() // unreachable
-
-	var (
-		flagVerbose   bool
-		flagDropShell bool
-	)
-	c := command.New(os.Stderr, log.Printf, "planterette", func([]string) error { internal.InstallOutput(flagVerbose); return nil }).
-		Flag(&flagVerbose, "v", command.BoolFlag(false), "Print debug messages to the console").
-		Flag(&flagDropShell, "s", command.BoolFlag(false), "Drop to a shell in place of next hakurei action")
-
-	{
-		var (
-			flagDropShellActivate bool
-		)
-		c.NewCommand("install", "Install an application from its package", func(args []string) error {
-			if len(args) != 1 {
-				log.Println("invalid argument")
-				return syscall.EINVAL
-			}
-			pkgPath := args[0]
-			if !path.IsAbs(pkgPath) {
-				if dir, err := os.Getwd(); err != nil {
-					log.Printf("cannot get current directory: %v", err)
-					return err
-				} else {
-					pkgPath = path.Join(dir, pkgPath)
-				}
-			}
-
-			/*
-				Look up paths to programs started by planterette.
-				This is done here to ease error handling as cleanup is not yet required.
-			*/
-
-			var (
-				_     = lookPath("zstd")
-				tar   = lookPath("tar")
-				chmod = lookPath("chmod")
-				rm    = lookPath("rm")
-			)
-
-			/*
-				Extract package and set up for cleanup.
-			*/
-
-			var workDir string
-			if p, err := os.MkdirTemp("", "planterette.*"); err != nil {
-				log.Printf("cannot create temporary directory: %v", err)
-				return err
-			} else {
-				workDir = p
-			}
-			cleanup := func() {
-				// should be faster than a native implementation
-				mustRun(chmod, "-R", "+w", workDir)
-				mustRun(rm, "-rf", workDir)
-			}
-			beforeRunFail.Store(&cleanup)
-
-			mustRun(tar, "-C", workDir, "-xf", pkgPath)
-
-			/*
-				Parse bundle and app metadata, do pre-install checks.
-			*/
-
-			bundle := loadAppInfo(path.Join(workDir, "bundle.json"), cleanup)
-			pathSet := pathSetByApp(bundle.ID)
-
-			a := bundle
-			if s, err := os.Stat(pathSet.metaPath); err != nil {
-				if !os.IsNotExist(err) {
-					cleanup()
-					log.Printf("cannot access %q: %v", pathSet.metaPath, err)
-					return err
-				}
-				// did not modify app, clean installation condition met later
-			} else if s.IsDir() {
-				cleanup()
-				log.Printf("metadata path %q is not a file", pathSet.metaPath)
-				return syscall.EBADMSG
-			} else {
-				a = loadAppInfo(pathSet.metaPath, cleanup)
-				if a.ID != bundle.ID {
-					cleanup()
-					log.Printf("app %q claims to have identifier %q",
-						bundle.ID, a.ID)
-					return syscall.EBADE
-				}
-				// sec: should verify credentials
-			}
-
-			if a != bundle {
-				// do not try to re-install
-				if a.NixGL == bundle.NixGL &&
-					a.CurrentSystem == bundle.CurrentSystem &&
-					a.Launcher == bundle.Launcher &&
-					a.ActivationPackage == bundle.ActivationPackage {
-					cleanup()
-					log.Printf("package %q is identical to local application %q",
-						pkgPath, a.ID)
-					return errSuccess
-				}
-
-				// identity determines uid
-				if a.Identity != bundle.Identity {
-					cleanup()
-					log.Printf("package %q identity %d differs from installed %d",
-						pkgPath, bundle.Identity, a.Identity)
-					return syscall.EBADE
-				}
-
-				// sec: should compare version string
-				hlog.Verbosef("installing application %q version %q over local %q",
-					bundle.ID, bundle.Version, a.Version)
-			} else {
-				hlog.Verbosef("application %q clean installation", bundle.ID)
-				// sec: should install credentials
-			}
-
-			/*
-				Setup steps for files owned by the target user.
-			*/
-
-			withCacheDir(ctx, "install", []string{
-				// export inner bundle path in the environment
-				"export BUNDLE=" + hst.Tmp + "/bundle",
-				// replace inner /etc
-				"mkdir -p etc",
-				"chmod -R +w etc",
-				"rm -rf etc",
-				"cp -dRf $BUNDLE/etc etc",
-				// replace inner /nix
-				"mkdir -p nix",
-				"chmod -R +w nix",
-				"rm -rf nix",
-				"cp -dRf /nix nix",
-				// copy from binary cache
-				"nix copy --offline --no-check-sigs --all --from file://$BUNDLE/res --to $PWD",
-				// deduplicate nix store
-				"nix store --offline --store $PWD optimise",
-				// make cache directory world-readable for autoetc
-				"chmod 0755 .",
-			}, workDir, bundle, pathSet, flagDropShell, cleanup)
-
-			if bundle.GPU {
-				withCacheDir(ctx, "mesa-wrappers", []string{
-					// link nixGL mesa wrappers
-					"mkdir -p nix/.nixGL",
-					"ln -s " + bundle.Mesa + "/bin/nixGLIntel nix/.nixGL/nixGL",
-					"ln -s " + bundle.Mesa + "/bin/nixVulkanIntel nix/.nixGL/nixVulkan",
-				}, workDir, bundle, pathSet, false, cleanup)
-			}
-
-			/*
-				Activate home-manager generation.
-			*/
-
-			withNixDaemon(ctx, "activate", []string{
-				// clean up broken links
-				"mkdir -p .local/state/{nix,home-manager}",
-				"chmod -R +w .local/state/{nix,home-manager}",
-				"rm -rf .local/state/{nix,home-manager}",
-				// run activation script
-				bundle.ActivationPackage + "/activate",
-			}, false, func(config *hst.Config) *hst.Config { return config },
-				bundle, pathSet, flagDropShellActivate, cleanup)
-
-			/*
-				Installation complete. Write metadata to block re-installs or downgrades.
-			*/
-
-			// serialise metadata to ensure consistency
-			if f, err := os.OpenFile(pathSet.metaPath+"~", os.O_CREATE|os.O_WRONLY|os.O_TRUNC, 0644); err != nil {
-				cleanup()
-				log.Printf("cannot create metadata file: %v", err)
-				return err
-			} else if err = json.NewEncoder(f).Encode(bundle); err != nil {
-				cleanup()
-				log.Printf("cannot write metadata: %v", err)
-				return err
-			} else if err = f.Close(); err != nil {
-				log.Printf("cannot close metadata file: %v", err)
-				// not fatal
-			}
-
-			if err := os.Rename(pathSet.metaPath+"~", pathSet.metaPath); err != nil {
-				cleanup()
-				log.Printf("cannot rename metadata file: %v", err)
-				return err
-			}
-
-			cleanup()
-			return errSuccess
-		}).
-			Flag(&flagDropShellActivate, "s", command.BoolFlag(false), "Drop to a shell on activation")
-	}
-
-	{
-		var (
-			flagDropShellNixGL bool
-			flagAutoDrivers    bool
-		)
-		c.NewCommand("start", "Start an application", func(args []string) error {
-			if len(args) < 1 {
-				log.Println("invalid argument")
-				return syscall.EINVAL
-			}
-
-			/*
-				Parse app metadata.
-			*/
-
-			id := args[0]
-			pathSet := pathSetByApp(id)
-			a := loadAppInfo(pathSet.metaPath, func() {})
-			if a.ID != id {
-				log.Printf("app %q claims to have identifier %q", id, a.ID)
-				return syscall.EBADE
-			}
-
-			/*
-				Prepare nixGL.
-			*/
-
-			if a.GPU && flagAutoDrivers {
-				withNixDaemon(ctx, "nix-gl", []string{
-					"mkdir -p /nix/.nixGL/auto",
-					"rm -rf /nix/.nixGL/auto",
-					"export NIXPKGS_ALLOW_UNFREE=1",
-					"nix build --impure " +
-						"--out-link /nix/.nixGL/auto/opengl " +
-						"--override-input nixpkgs path:/etc/nixpkgs " +
-						"path:" + a.NixGL,
-					"nix build --impure " +
-						"--out-link /nix/.nixGL/auto/vulkan " +
-						"--override-input nixpkgs path:/etc/nixpkgs " +
-						"path:" + a.NixGL + "#nixVulkanNvidia",
-				}, true, func(config *hst.Config) *hst.Config {
-					config.Container.Filesystem = append(config.Container.Filesystem, []*hst.FilesystemConfig{
-						{Src: "/etc/resolv.conf"},
-						{Src: "/sys/block"},
-						{Src: "/sys/bus"},
-						{Src: "/sys/class"},
-						{Src: "/sys/dev"},
-						{Src: "/sys/devices"},
-					}...)
-					appendGPUFilesystem(config)
-					return config
-				}, a, pathSet, flagDropShellNixGL, func() {})
-			}
-
-			/*
-				Create app configuration.
-			*/
-
-			argv := make([]string, 1, len(args))
-			if !flagDropShell {
-				argv[0] = a.Launcher
-			} else {
-				argv[0] = shellPath
-			}
-			argv = append(argv, args[1:]...)
-
-			config := a.toFst(pathSet, argv, flagDropShell)
-
-			/*
-				Expose GPU devices.
-			*/
-
-			if a.GPU {
-				config.Container.Filesystem = append(config.Container.Filesystem,
-					&hst.FilesystemConfig{Src: path.Join(pathSet.nixPath, ".nixGL"), Dst: path.Join(hst.Tmp, "nixGL")})
-				appendGPUFilesystem(config)
-			}
-
-			/*
-				Spawn app.
-			*/
-
-			mustRunApp(ctx, config, func() {})
-			return errSuccess
-		}).
-			Flag(&flagDropShellNixGL, "s", command.BoolFlag(false), "Drop to a shell on nixGL build").
-			Flag(&flagAutoDrivers, "auto-drivers", command.BoolFlag(false), "Attempt automatic opengl driver detection")
-	}
-
-	c.MustParse(os.Args[1:], func(err error) {
-		hlog.Verbosef("command returned %v", err)
-		if errors.Is(err, errSuccess) {
-			hlog.BeforeExit()
-			os.Exit(0)
-		}
-	})
-	log.Fatal("unreachable")
-}

cmd/planterette/paths.go

@@ -1,101 +0,0 @@
-package main
-
-import (
-	"log"
-	"os"
-	"os/exec"
-	"path"
-	"strconv"
-	"sync/atomic"
-
-	"hakurei.app/hst"
-	"hakurei.app/internal/hlog"
-)
-
-var (
-	dataHome string
-)
-
-func init() {
-	// dataHome
-	if p, ok := os.LookupEnv("HAKUREI_DATA_HOME"); ok {
-		dataHome = p
-	} else {
-		dataHome = "/var/lib/hakurei/" + strconv.Itoa(os.Getuid())
-	}
-}
-
-func lookPath(file string) string {
-	if p, err := exec.LookPath(file); err != nil {
-		log.Fatalf("%s: command not found", file)
-		return ""
-	} else {
-		return p
-	}
-}
-
-var beforeRunFail = new(atomic.Pointer[func()])
-
-func mustRun(name string, arg ...string) {
-	hlog.Verbosef("spawning process: %q %q", name, arg)
-	cmd := exec.Command(name, arg...)
-	cmd.Stdin, cmd.Stdout, cmd.Stderr = os.Stdin, os.Stdout, os.Stderr
-	if err := cmd.Run(); err != nil {
-		if f := beforeRunFail.Swap(nil); f != nil {
-			(*f)()
-		}
-		log.Fatalf("%s: %v", name, err)
-	}
-}
-
-type appPathSet struct {
-	// ${dataHome}/${id}
-	baseDir string
-	// ${baseDir}/app
-	metaPath string
-	// ${baseDir}/files
-	homeDir string
-	// ${baseDir}/cache
-	cacheDir string
-	// ${baseDir}/cache/nix
-	nixPath string
-}
-
-func pathSetByApp(id string) *appPathSet {
-	pathSet := new(appPathSet)
-	pathSet.baseDir = path.Join(dataHome, id)
-	pathSet.metaPath = path.Join(pathSet.baseDir, "app")
-	pathSet.homeDir = path.Join(pathSet.baseDir, "files")
-	pathSet.cacheDir = path.Join(pathSet.baseDir, "cache")
-	pathSet.nixPath = path.Join(pathSet.cacheDir, "nix")
-	return pathSet
-}
-
-func appendGPUFilesystem(config *hst.Config) {
-	config.Container.Filesystem = append(config.Container.Filesystem, []*hst.FilesystemConfig{
-		// flatpak commit 763a686d874dd668f0236f911de00b80766ffe79
-		{Src: "/dev/dri", Device: true},
-		// mali
-		{Src: "/dev/mali", Device: true},
-		{Src: "/dev/mali0", Device: true},
-		{Src: "/dev/umplock", Device: true},
-		// nvidia
-		{Src: "/dev/nvidiactl", Device: true},
-		{Src: "/dev/nvidia-modeset", Device: true},
-		// nvidia OpenCL/CUDA
-		{Src: "/dev/nvidia-uvm", Device: true},
-		{Src: "/dev/nvidia-uvm-tools", Device: true},
-
-		// flatpak commit d2dff2875bb3b7e2cd92d8204088d743fd07f3ff
-		{Src: "/dev/nvidia0", Device: true}, {Src: "/dev/nvidia1", Device: true},
-		{Src: "/dev/nvidia2", Device: true}, {Src: "/dev/nvidia3", Device: true},
-		{Src: "/dev/nvidia4", Device: true}, {Src: "/dev/nvidia5", Device: true},
-		{Src: "/dev/nvidia6", Device: true}, {Src: "/dev/nvidia7", Device: true},
-		{Src: "/dev/nvidia8", Device: true}, {Src: "/dev/nvidia9", Device: true},
-		{Src: "/dev/nvidia10", Device: true}, {Src: "/dev/nvidia11", Device: true},
-		{Src: "/dev/nvidia12", Device: true}, {Src: "/dev/nvidia13", Device: true},
-		{Src: "/dev/nvidia14", Device: true}, {Src: "/dev/nvidia15", Device: true},
-		{Src: "/dev/nvidia16", Device: true}, {Src: "/dev/nvidia17", Device: true},
-		{Src: "/dev/nvidia18", Device: true}, {Src: "/dev/nvidia19", Device: true},
-	}...)
-}

cmd/planterette/proc.go

@@ -1,60 +0,0 @@
-package main
-
-import (
-	"context"
-	"encoding/json"
-	"errors"
-	"io"
-	"log"
-	"os"
-	"os/exec"
-
-	"hakurei.app/hst"
-	"hakurei.app/internal"
-	"hakurei.app/internal/hlog"
-)
-
-var hakureiPath = internal.MustHakureiPath()
-
-func mustRunApp(ctx context.Context, config *hst.Config, beforeFail func()) {
-	var (
-		cmd *exec.Cmd
-		st  io.WriteCloser
-	)
-
-	if r, w, err := os.Pipe(); err != nil {
-		beforeFail()
-		log.Fatalf("cannot pipe: %v", err)
-	} else {
-		if hlog.Load() {
-			cmd = exec.CommandContext(ctx, hakureiPath, "-v", "app", "3")
-		} else {
-			cmd = exec.CommandContext(ctx, hakureiPath, "app", "3")
-		}
-		cmd.Stdin, cmd.Stdout, cmd.Stderr = os.Stdin, os.Stdout, os.Stderr
-		cmd.ExtraFiles = []*os.File{r}
-		st = w
-	}
-
-	go func() {
-		if err := json.NewEncoder(st).Encode(config); err != nil {
-			beforeFail()
-			log.Fatalf("cannot send configuration: %v", err)
-		}
-	}()
-
-	if err := cmd.Start(); err != nil {
-		beforeFail()
-		log.Fatalf("cannot start hakurei: %v", err)
-	}
-	if err := cmd.Wait(); err != nil {
-		var exitError *exec.ExitError
-		if errors.As(err, &exitError) {
-			beforeFail()
-			internal.Exit(exitError.ExitCode())
-		} else {
-			beforeFail()
-			log.Fatalf("cannot wait: %v", err)
-		}
-	}
-}

cmd/planterette/test/configuration.nix

@@ -1,62 +0,0 @@
-{ pkgs, ... }:
-{
-  users.users = {
-    alice = {
-      isNormalUser = true;
-      description = "Alice Foobar";
-      password = "foobar";
-      uid = 1000;
-    };
-  };
-
-  home-manager.users.alice.home.stateVersion = "24.11";
-
-  # Automatically login on tty1 as a normal user:
-  services.getty.autologinUser = "alice";
-
-  environment = {
-    variables = {
-      SWAYSOCK = "/tmp/sway-ipc.sock";
-      WLR_RENDERER = "pixman";
-    };
-  };
-
-  # Automatically configure and start Sway when logging in on tty1:
-  programs.bash.loginShellInit = ''
-    if [ "$(tty)" = "/dev/tty1" ]; then
-      set -e
-
-      mkdir -p ~/.config/sway
-      (sed s/Mod4/Mod1/ /etc/sway/config &&
-      echo 'output * bg ${pkgs.nixos-artwork.wallpapers.simple-light-gray.gnomeFilePath} fill' &&
-      echo 'output Virtual-1 res 1680x1050') > ~/.config/sway/config
-
-      sway --validate
-      systemd-cat --identifier=session sway && touch /tmp/sway-exit-ok
-    fi
-  '';
-
-  programs.sway.enable = true;
-
-  virtualisation = {
-    diskSize = 6 * 1024;
-
-    qemu.options = [
-      # Need to switch to a different GPU driver than the default one (-vga std) so that Sway can launch:
-      "-vga none -device virtio-gpu-pci"
-
-      # Increase zstd performance:
-      "-smp 8"
-    ];
-  };
-
-  environment.hakurei = {
-    enable = true;
-    stateDir = "/var/lib/hakurei";
-    users.alice = 0;
-
-    extraHomeConfig = {
-      home.stateVersion = "23.05";
-    };
-  };
-}

cmd/planterette/test/default.nix

@@ -1,34 +0,0 @@
-{
-  nixosTest,
-  callPackage,
-
-  system,
-  self,
-}:
-let
-  buildPackage = self.buildPackage.${system};
-in
-nixosTest {
-  name = "planterette";
-  nodes.machine = {
-    environment.etc = {
-      "foot.pkg".source = callPackage ./foot.nix { inherit buildPackage; };
-    };
-
-    imports = [
-      ./configuration.nix
-
-      self.nixosModules.hakurei
-      self.inputs.home-manager.nixosModules.home-manager
-    ];
-  };
-
-  # adapted from nixos sway integration tests
-
-  # testScriptWithTypes:49: error: Cannot call function of unknown type
-  #           (machine.succeed if succeed else machine.execute)(
-  #           ^
-  # Found 1 error in 1 file (checked 1 source file)
-  skipTypeCheck = true;
-  testScript = builtins.readFile ./test.py;
-}

cmd/planterette/test/foot.nix

@@ -1,48 +0,0 @@
-{
-  lib,
-  buildPackage,
-  foot,
-  wayland-utils,
-  inconsolata,
-}:
-
-buildPackage {
-  name = "foot";
-  inherit (foot) version;
-
-  identity = 2;
-  id = "org.codeberg.dnkl.foot";
-
-  modules = [
-    {
-      home.packages = [
-        foot
-
-        # For wayland-info:
-        wayland-utils
-      ];
-    }
-  ];
-
-  nixosModules = [
-    {
-      # To help with OCR:
-      environment.etc."xdg/foot/foot.ini".text = lib.generators.toINI { } {
-        main = {
-          font = "inconsolata:size=14";
-        };
-        colors = rec {
-          foreground = "000000";
-          background = "ffffff";
-          regular2 = foreground;
-        };
-      };
-
-      fonts.packages = [ inconsolata ];
-    }
-  ];
-
-  script = ''
-    exec foot "$@"
-  '';
-}

cmd/planterette/test/test.py

@@ -1,108 +0,0 @@
-import json
-import shlex
-
-q = shlex.quote
-NODE_GROUPS = ["nodes", "floating_nodes"]
-
-
-def swaymsg(command: str = "", succeed=True, type="command"):
-    assert command != "" or type != "command", "Must specify command or type"
-    shell = q(f"swaymsg -t {q(type)} -- {q(command)}")
-    with machine.nested(
-            f"sending swaymsg {shell!r}" + " (allowed to fail)" * (not succeed)
-    ):
-        ret = (machine.succeed if succeed else machine.execute)(
-            f"su - alice -c {shell}"
-        )
-
-    # execute also returns a status code, but disregard.
-    if not succeed:
-        _, ret = ret
-
-    if not succeed and not ret:
-        return None
-
-    parsed = json.loads(ret)
-    return parsed
-
-
-def walk(tree):
-    yield tree
-    for group in NODE_GROUPS:
-        for node in tree.get(group, []):
-            yield from walk(node)
-
-
-def wait_for_window(pattern):
-    def func(last_chance):
-        nodes = (node["name"] for node in walk(swaymsg(type="get_tree")))
-
-        if last_chance:
-            nodes = list(nodes)
-            machine.log(f"Last call! Current list of windows: {nodes}")
-
-        return any(pattern in name for name in nodes)
-
-    retry(func)
-
-
-def collect_state_ui(name):
-    swaymsg(f"exec hakurei ps > '/tmp/{name}.ps'")
-    machine.copy_from_vm(f"/tmp/{name}.ps", "")
-    swaymsg(f"exec hakurei --json ps > '/tmp/{name}.json'")
-    machine.copy_from_vm(f"/tmp/{name}.json", "")
-    machine.screenshot(name)
-
-
-def check_state(name, enablements):
-    instances = json.loads(machine.succeed("sudo -u alice -i XDG_RUNTIME_DIR=/run/user/1000 hakurei --json ps"))
-    if len(instances) != 1:
-        raise Exception(f"unexpected state length {len(instances)}")
-    instance = next(iter(instances.values()))
-
-    config = instance['config']
-
-    if len(config['args']) != 1 or not (config['args'][0].startswith("/nix/store/")) or f"hakurei-{name}-" not in (config['args'][0]):
-        raise Exception(f"unexpected args {instance['config']['args']}")
-
-    if config['enablements'] != enablements:
-        raise Exception(f"unexpected enablements {instance['config']['enablements']}")
-
-
-start_all()
-machine.wait_for_unit("multi-user.target")
-
-# To check hakurei's version:
-print(machine.succeed("sudo -u alice -i hakurei version"))
-
-# Wait for Sway to complete startup:
-machine.wait_for_file("/run/user/1000/wayland-1")
-machine.wait_for_file("/tmp/sway-ipc.sock")
-
-# Prepare planterette directory:
-machine.succeed("install -dm 0700 -o alice -g users /var/lib/hakurei/1000")
-
-# Install planterette app:
-swaymsg("exec planterette -v install /etc/foot.pkg && touch /tmp/planterette-install-ok")
-machine.wait_for_file("/tmp/planterette-install-ok")
-
-# Start app (foot) with Wayland enablement:
-swaymsg("exec planterette -v start org.codeberg.dnkl.foot")
-wait_for_window("hakurei@machine-foot")
-machine.send_chars("clear; wayland-info && touch /tmp/success-client\n")
-machine.wait_for_file("/tmp/hakurei.1000/tmpdir/2/success-client")
-collect_state_ui("app_wayland")
-check_state("foot", 13)
-# Verify acl on XDG_RUNTIME_DIR:
-print(machine.succeed("getfacl --absolute-names --omit-header --numeric /run/user/1000 | grep 1000002"))
-machine.send_chars("exit\n")
-machine.wait_until_fails("pgrep foot")
-# Verify acl cleanup on XDG_RUNTIME_DIR:
-machine.wait_until_fails("getfacl --absolute-names --omit-header --numeric /run/user/1000 | grep 1000002")
-
-# Exit Sway and verify process exit status 0:
-swaymsg("exit", succeed=False)
-machine.wait_for_file("/tmp/sway-exit-ok")
-
-# Print hakurei runDir contents:
-print(machine.succeed("find /run/user/1000/hakurei"))

cmd/planterette/with.go

@@ -1,114 +0,0 @@
-package main
-
-import (
-	"context"
-	"path"
-	"strings"
-
-	"hakurei.app/container/seccomp"
-	"hakurei.app/hst"
-	"hakurei.app/internal"
-)
-
-func withNixDaemon(
-	ctx context.Context,
-	action string, command []string, net bool, updateConfig func(config *hst.Config) *hst.Config,
-	app *appInfo, pathSet *appPathSet, dropShell bool, beforeFail func(),
-) {
-	mustRunAppDropShell(ctx, updateConfig(&hst.Config{
-		ID: app.ID,
-
-		Path: shellPath,
-		Args: []string{shellPath, "-lc", "rm -f /nix/var/nix/daemon-socket/socket && " +
-			// start nix-daemon
-			"nix-daemon --store / & " +
-			// wait for socket to appear
-			"(while [ ! -S /nix/var/nix/daemon-socket/socket ]; do sleep 0.01; done) && " +
-			// create directory so nix stops complaining
-			"mkdir -p /nix/var/nix/profiles/per-user/root/channels && " +
-			strings.Join(command, " && ") +
-			// terminate nix-daemon
-			" && pkill nix-daemon",
-		},
-
-		Username: "hakurei",
-		Shell:    shellPath,
-		Data:     pathSet.homeDir,
-		Dir:      path.Join("/data/data", app.ID),
-		ExtraPerms: []*hst.ExtraPermConfig{
-			{Path: dataHome, Execute: true},
-			{Ensure: true, Path: pathSet.baseDir, Read: true, Write: true, Execute: true},
-		},
-
-		Identity: app.Identity,
-
-		Container: &hst.ContainerConfig{
-			Hostname:     formatHostname(app.Name) + "-" + action,
-			Userns:       true, // nix sandbox requires userns
-			Net:          net,
-			SeccompFlags: seccomp.AllowMultiarch,
-			Tty:          dropShell,
-			Filesystem: []*hst.FilesystemConfig{
-				{Src: pathSet.nixPath, Dst: "/nix", Write: true, Must: true},
-			},
-			Link: [][2]string{
-				{app.CurrentSystem, "/run/current-system"},
-				{"/run/current-system/sw/bin", "/bin"},
-				{"/run/current-system/sw/bin", "/usr/bin"},
-			},
-			Etc:     path.Join(pathSet.cacheDir, "etc"),
-			AutoEtc: true,
-		},
-	}), dropShell, beforeFail)
-}
-
-func withCacheDir(
-	ctx context.Context,
-	action string, command []string, workDir string,
-	app *appInfo, pathSet *appPathSet, dropShell bool, beforeFail func()) {
-	mustRunAppDropShell(ctx, &hst.Config{
-		ID: app.ID,
-
-		Path: shellPath,
-		Args: []string{shellPath, "-lc", strings.Join(command, " && ")},
-
-		Username: "nixos",
-		Shell:    shellPath,
-		Data:     pathSet.cacheDir, // this also ensures cacheDir via shim
-		Dir:      path.Join("/data/data", app.ID, "cache"),
-		ExtraPerms: []*hst.ExtraPermConfig{
-			{Path: dataHome, Execute: true},
-			{Ensure: true, Path: pathSet.baseDir, Read: true, Write: true, Execute: true},
-			{Path: workDir, Execute: true},
-		},
-
-		Identity: app.Identity,
-
-		Container: &hst.ContainerConfig{
-			Hostname:     formatHostname(app.Name) + "-" + action,
-			SeccompFlags: seccomp.AllowMultiarch,
-			Tty:          dropShell,
-			Filesystem: []*hst.FilesystemConfig{
-				{Src: path.Join(workDir, "nix"), Dst: "/nix", Must: true},
-				{Src: workDir, Dst: path.Join(hst.Tmp, "bundle"), Must: true},
-			},
-			Link: [][2]string{
-				{app.CurrentSystem, "/run/current-system"},
-				{"/run/current-system/sw/bin", "/bin"},
-				{"/run/current-system/sw/bin", "/usr/bin"},
-			},
-			Etc:     path.Join(workDir, "etc"),
-			AutoEtc: true,
-		},
-	}, dropShell, beforeFail)
-}
-
-func mustRunAppDropShell(ctx context.Context, config *hst.Config, dropShell bool, beforeFail func()) {
-	if dropShell {
-		config.Args = []string{shellPath, "-l"}
-		mustRunApp(ctx, config, beforeFail)
-		beforeFail()
-		internal.Exit(0)
-	}
-	mustRunApp(ctx, config, beforeFail)
-}

cmd/sharefs/fuse-operations.c

@@ -0,0 +1,282 @@
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE /* O_DIRECT */
+#endif
+
+#include <dirent.h>
+#include <errno.h>
+#include <unistd.h>
+
+/* TODO(ophestra): remove after 05ce67fea99ca09cd4b6625cff7aec9cc222dd5a reaches a release */
+#include <sys/syscall.h>
+
+#include "fuse-operations.h"
+
+/* MUST_TRANSLATE_PATHNAME translates a userspace pathname to a relative pathname;
+ * the resulting address points to a constant string or part of pathname, it is never heap allocated. */
+#define MUST_TRANSLATE_PATHNAME(pathname) \
+    do {                                  \
+        if (pathname == NULL)             \
+            return -EINVAL;               \
+        while (*pathname == '/')          \
+            pathname++;                   \
+        if (*pathname == '\0')            \
+            pathname = ".";               \
+    } while (0)
+
+/* GET_CONTEXT_PRIV obtains fuse context and private data for the calling thread. */
+#define GET_CONTEXT_PRIV(ctx, priv) \
+    do {                            \
+        ctx = fuse_get_context();   \
+        priv = ctx->private_data;   \
+    } while (0)
+
+/* impl_getattr modifies a struct stat from the kernel to present to userspace;
+ * impl_getattr returns a negative errno style error code. */
+static int impl_getattr(struct fuse_context *ctx, struct stat *statbuf) {
+    /* allowlist of permitted types */
+    if (!S_ISDIR(statbuf->st_mode) && !S_ISREG(statbuf->st_mode) && !S_ISLNK(statbuf->st_mode)) {
+        return -ENOTRECOVERABLE; /* returning an errno causes all operations on the file to return EIO */
+    }
+
+#define OVERRIDE_PERM(v) (statbuf->st_mode & ~0777) | (v & 0777)
+    if (S_ISDIR(statbuf->st_mode))
+        statbuf->st_mode = OVERRIDE_PERM(SHAREFS_PERM_DIR);
+    else if (S_ISREG(statbuf->st_mode))
+        statbuf->st_mode = OVERRIDE_PERM(SHAREFS_PERM_REG);
+    else
+        statbuf->st_mode = 0; /* should always be symlink in this case */
+
+    statbuf->st_uid = ctx->uid;
+    statbuf->st_gid = SHAREFS_MEDIA_RW_ID;
+    statbuf->st_ctim = statbuf->st_mtim;
+    statbuf->st_nlink = 1;
+    return 0;
+}
+
+/* fuse_operations implementation */
+
+int sharefs_getattr(const char *pathname, struct stat *statbuf, struct fuse_file_info *fi) {
+    struct fuse_context *ctx;
+    struct sharefs_private *priv;
+    GET_CONTEXT_PRIV(ctx, priv);
+    MUST_TRANSLATE_PATHNAME(pathname);
+
+    (void)fi;
+
+    if (fstatat(priv->dirfd, pathname, statbuf, AT_SYMLINK_NOFOLLOW) == -1)
+        return -errno;
+    return impl_getattr(ctx, statbuf);
+}
+
+int sharefs_readdir(const char *pathname, void *buf, fuse_fill_dir_t filler, off_t offset, struct fuse_file_info *fi, enum fuse_readdir_flags flags) {
+    int fd;
+    DIR *dp;
+    struct stat st;
+    int ret = 0;
+    struct dirent *de;
+
+    struct fuse_context *ctx;
+    struct sharefs_private *priv;
+    GET_CONTEXT_PRIV(ctx, priv);
+    MUST_TRANSLATE_PATHNAME(pathname);
+
+    (void)offset;
+    (void)fi;
+
+    if ((fd = openat(priv->dirfd, pathname, O_RDONLY | O_DIRECTORY | O_CLOEXEC)) == -1)
+        return -errno;
+    if ((dp = fdopendir(fd)) == NULL) {
+        close(fd);
+        return -errno;
+    }
+
+    errno = 0; /* for the next readdir call */
+    while ((de = readdir(dp)) != NULL) {
+        if (flags & FUSE_READDIR_PLUS) {
+            if (fstatat(dirfd(dp), de->d_name, &st, AT_SYMLINK_NOFOLLOW) == -1) {
+                ret = -errno;
+                break;
+            }
+
+            if ((ret = impl_getattr(ctx, &st)) < 0)
+                break;
+
+            errno = 0;
+            ret = filler(buf, de->d_name, &st, 0, FUSE_FILL_DIR_PLUS);
+        } else
+            ret = filler(buf, de->d_name, NULL, 0, 0);
+
+        if (ret != 0) {
+            ret = errno != 0 ? -errno : -EIO; /* filler */
+            break;
+        }
+
+        errno = 0; /* for the next readdir call */
+    }
+    if (ret == 0 && errno != 0)
+        ret = -errno; /* readdir */
+
+    closedir(dp);
+    return ret;
+}
+
+int sharefs_mkdir(const char *pathname, mode_t mode) {
+    struct fuse_context *ctx;
+    struct sharefs_private *priv;
+    GET_CONTEXT_PRIV(ctx, priv);
+    MUST_TRANSLATE_PATHNAME(pathname);
+
+    (void)mode;
+
+    if (mkdirat(priv->dirfd, pathname, SHAREFS_PERM_DIR) == -1)
+        return -errno;
+    return 0;
+}
+
+int sharefs_unlink(const char *pathname) {
+    struct fuse_context *ctx;
+    struct sharefs_private *priv;
+    GET_CONTEXT_PRIV(ctx, priv);
+    MUST_TRANSLATE_PATHNAME(pathname);
+
+    if (unlinkat(priv->dirfd, pathname, 0) == -1)
+        return -errno;
+    return 0;
+}
+
+int sharefs_rmdir(const char *pathname) {
+    struct fuse_context *ctx;
+    struct sharefs_private *priv;
+    GET_CONTEXT_PRIV(ctx, priv);
+    MUST_TRANSLATE_PATHNAME(pathname);
+
+    if (unlinkat(priv->dirfd, pathname, AT_REMOVEDIR) == -1)
+        return -errno;
+    return 0;
+}
+
+int sharefs_rename(const char *oldpath, const char *newpath, unsigned int flags) {
+    struct fuse_context *ctx;
+    struct sharefs_private *priv;
+    GET_CONTEXT_PRIV(ctx, priv);
+    MUST_TRANSLATE_PATHNAME(oldpath);
+    MUST_TRANSLATE_PATHNAME(newpath);
+
+    /* TODO(ophestra): replace with wrapper after 05ce67fea99ca09cd4b6625cff7aec9cc222dd5a reaches a release */
+    if (syscall(__NR_renameat2, priv->dirfd, oldpath, priv->dirfd, newpath, flags) == -1)
+        return -errno;
+    return 0;
+}
+
+int sharefs_truncate(const char *pathname, off_t length, struct fuse_file_info *fi) {
+    int fd;
+    int ret;
+
+    struct fuse_context *ctx;
+    struct sharefs_private *priv;
+    GET_CONTEXT_PRIV(ctx, priv);
+    MUST_TRANSLATE_PATHNAME(pathname);
+
+    (void)fi;
+
+    if ((fd = openat(priv->dirfd, pathname, O_WRONLY | O_CLOEXEC)) == -1)
+        return -errno;
+    if ((ret = ftruncate(fd, length)) == -1)
+        ret = -errno;
+    close(fd);
+    return ret;
+}
+
+int sharefs_utimens(const char *pathname, const struct timespec times[2], struct fuse_file_info *fi) {
+    struct fuse_context *ctx;
+    struct sharefs_private *priv;
+    GET_CONTEXT_PRIV(ctx, priv);
+    MUST_TRANSLATE_PATHNAME(pathname);
+
+    (void)fi;
+
+    if (utimensat(priv->dirfd, pathname, times, AT_SYMLINK_NOFOLLOW) == -1)
+        return -errno;
+    return 0;
+}
+
+int sharefs_create(const char *pathname, mode_t mode, struct fuse_file_info *fi) {
+    int fd;
+
+    struct fuse_context *ctx;
+    struct sharefs_private *priv;
+    GET_CONTEXT_PRIV(ctx, priv);
+    MUST_TRANSLATE_PATHNAME(pathname);
+
+    (void)mode;
+
+    if ((fd = openat(priv->dirfd, pathname, fi->flags & ~SHAREFS_FORBIDDEN_FLAGS, SHAREFS_PERM_REG)) == -1)
+        return -errno;
+    fi->fh = fd;
+    return 0;
+}
+
+int sharefs_open(const char *pathname, struct fuse_file_info *fi) {
+    int fd;
+
+    struct fuse_context *ctx;
+    struct sharefs_private *priv;
+    GET_CONTEXT_PRIV(ctx, priv);
+    MUST_TRANSLATE_PATHNAME(pathname);
+
+    if ((fd = openat(priv->dirfd, pathname, fi->flags & ~SHAREFS_FORBIDDEN_FLAGS)) == -1)
+        return -errno;
+    fi->fh = fd;
+    return 0;
+}
+
+int sharefs_read(const char *pathname, char *buf, size_t count, off_t offset, struct fuse_file_info *fi) {
+    int ret;
+
+    (void)pathname;
+
+    if ((ret = pread(fi->fh, buf, count, offset)) == -1)
+        return -errno;
+    return ret;
+}
+
+int sharefs_write(const char *pathname, const char *buf, size_t count, off_t offset, struct fuse_file_info *fi) {
+    int ret;
+
+    (void)pathname;
+
+    if ((ret = pwrite(fi->fh, buf, count, offset)) == -1)
+        return -errno;
+    return ret;
+}
+
+int sharefs_statfs(const char *pathname, struct statvfs *statbuf) {
+    int fd;
+    int ret;
+
+    struct fuse_context *ctx;
+    struct sharefs_private *priv;
+    GET_CONTEXT_PRIV(ctx, priv);
+    MUST_TRANSLATE_PATHNAME(pathname);
+
+    if ((fd = openat(priv->dirfd, pathname, O_RDONLY | O_CLOEXEC)) == -1)
+        return -errno;
+    if ((ret = fstatvfs(fd, statbuf)) == -1)
+        ret = -errno;
+    close(fd);
+    return ret;
+}
+
+int sharefs_release(const char *pathname, struct fuse_file_info *fi) {
+    (void)pathname;
+
+    return close(fi->fh);
+}
+
+int sharefs_fsync(const char *pathname, int datasync, struct fuse_file_info *fi) {
+    (void)pathname;
+
+    if (datasync ? fdatasync(fi->fh) : fsync(fi->fh) == -1)
+        return -errno;
+    return 0;
+}

cmd/sharefs/fuse-operations.h

@@ -0,0 +1,34 @@
+#define FUSE_USE_VERSION FUSE_MAKE_VERSION(3, 12)
+#include <fuse.h>
+#include <fuse_lowlevel.h> /* for fuse_cmdline_help */
+
+#if (FUSE_VERSION < FUSE_MAKE_VERSION(3, 12))
+#error This package requires libfuse >= v3.12
+#endif
+
+#define SHAREFS_MEDIA_RW_ID (1 << 10) - 1 /* owning gid presented to userspace */
+#define SHAREFS_PERM_DIR 0770             /* permission bits for directories presented to userspace */
+#define SHAREFS_PERM_REG 0660             /* permission bits for regular files presented to userspace */
+#define SHAREFS_FORBIDDEN_FLAGS O_DIRECT  /* these open flags are cleared unconditionally */
+
+/* sharefs_private is populated by sharefs_init and contains process-wide context */
+struct sharefs_private {
+    int dirfd;       /* source dirfd opened during sharefs_init */
+    uintptr_t setup; /* cgo handle of opaque setup state */
+};
+
+int sharefs_getattr(const char *pathname, struct stat *statbuf, struct fuse_file_info *fi);
+int sharefs_readdir(const char *pathname, void *buf, fuse_fill_dir_t filler, off_t offset, struct fuse_file_info *fi, enum fuse_readdir_flags flags);
+int sharefs_mkdir(const char *pathname, mode_t mode);
+int sharefs_unlink(const char *pathname);
+int sharefs_rmdir(const char *pathname);
+int sharefs_rename(const char *oldpath, const char *newpath, unsigned int flags);
+int sharefs_truncate(const char *pathname, off_t length, struct fuse_file_info *fi);
+int sharefs_utimens(const char *pathname, const struct timespec times[2], struct fuse_file_info *fi);
+int sharefs_create(const char *pathname, mode_t mode, struct fuse_file_info *fi);
+int sharefs_open(const char *pathname, struct fuse_file_info *fi);
+int sharefs_read(const char *pathname, char *buf, size_t count, off_t offset, struct fuse_file_info *fi);
+int sharefs_write(const char *pathname, const char *buf, size_t count, off_t offset, struct fuse_file_info *fi);
+int sharefs_statfs(const char *pathname, struct statvfs *statbuf);
+int sharefs_release(const char *pathname, struct fuse_file_info *fi);
+int sharefs_fsync(const char *pathname, int datasync, struct fuse_file_info *fi);

cmd/sharefs/fuse.go

@@ -0,0 +1,570 @@
+package main
+
+/*
+#cgo pkg-config: --static fuse3
+
+#include "fuse-operations.h"
+#include <stdlib.h>
+#include <string.h>
+
+extern void *sharefs_init(struct fuse_conn_info *conn, struct fuse_config *cfg);
+extern void sharefs_destroy(void *private_data);
+
+typedef void (*closure)();
+static inline struct fuse_opt _FUSE_OPT_END() { return (struct fuse_opt)FUSE_OPT_END; };
+*/
+import "C"
+import (
+	"context"
+	"encoding/gob"
+	"errors"
+	"fmt"
+	"log"
+	"os"
+	"os/exec"
+	"os/signal"
+	"path/filepath"
+	"runtime"
+	"runtime/cgo"
+	"strconv"
+	"syscall"
+	"unsafe"
+
+	"hakurei.app/check"
+	"hakurei.app/container"
+	"hakurei.app/container/std"
+	"hakurei.app/fhs"
+	"hakurei.app/hst"
+	"hakurei.app/internal/helper/proc"
+	"hakurei.app/internal/info"
+	"hakurei.app/message"
+)
+
+type (
+	// closure represents a C function pointer.
+	closure = C.closure
+
+	// fuseArgs represents the fuse_args structure.
+	fuseArgs = C.struct_fuse_args
+
+	// setupState holds state used for setup. Its cgo handle is included in
+	// sharefs_private and considered opaque to non-setup callbacks.
+	setupState struct {
+		// Whether sharefs_init failed.
+		initFailed bool
+
+		// Whether to create source directory as root.
+		mkdir bool
+
+		// Open file descriptor to fuse.
+		Fuse int
+
+		// Pathname to open for dirfd.
+		Source *check.Absolute
+		// New uid and gid to set by sharefs_init when starting as root.
+		Setuid, Setgid int
+	}
+)
+
+func init() { gob.Register(new(setupState)) }
+
+// destroySetup invalidates the setup [cgo.Handle] in a sharefs_private structure.
+func destroySetup(private_data unsafe.Pointer) (ok bool) {
+	if private_data == nil {
+		return false
+	}
+	priv := (*C.struct_sharefs_private)(private_data)
+
+	if h := cgo.Handle(priv.setup); h != 0 {
+		priv.setup = 0
+		h.Delete()
+		ok = true
+	}
+	return
+}
+
+//export sharefs_init
+func sharefs_init(
+	_ *C.struct_fuse_conn_info,
+	cfg *C.struct_fuse_config,
+) unsafe.Pointer {
+	ctx := C.fuse_get_context()
+	priv := (*C.struct_sharefs_private)(ctx.private_data)
+	setup := cgo.Handle(priv.setup).Value().(*setupState)
+
+	if os.Geteuid() == 0 {
+		log.Println("filesystem daemon must not run as root")
+		goto fail
+	}
+
+	cfg.use_ino = C.true
+	cfg.direct_io = C.false
+	// getattr is context-dependent
+	cfg.attr_timeout = 0
+	cfg.entry_timeout = 0
+	cfg.negative_timeout = 0
+
+	// all future filesystem operations happen through this dirfd
+	if fd, err := syscall.Open(
+		setup.Source.String(),
+		syscall.O_DIRECTORY|syscall.O_RDONLY|syscall.O_CLOEXEC,
+		0,
+	); err != nil {
+		log.Printf("cannot open %q: %v", setup.Source, err)
+		goto fail
+	} else if err = syscall.Fchdir(fd); err != nil {
+		_ = syscall.Close(fd)
+		log.Printf("cannot enter %q: %s", setup.Source, err)
+		goto fail
+	} else {
+		priv.dirfd = C.int(fd)
+	}
+
+	return ctx.private_data
+
+fail:
+	setup.initFailed = true
+	C.fuse_exit(ctx.fuse)
+	return nil
+}
+
+//export sharefs_destroy
+func sharefs_destroy(private_data unsafe.Pointer) {
+	if private_data != nil {
+		destroySetup(private_data)
+		priv := (*C.struct_sharefs_private)(private_data)
+
+		if err := syscall.Close(int(priv.dirfd)); err != nil {
+			log.Printf("cannot close source directory: %v", err)
+		}
+	}
+}
+
+// showHelp prints the help message.
+func showHelp(args *fuseArgs) {
+	executableName := sharefsName
+	if args.argc > 0 {
+		executableName = filepath.Base(C.GoString(*args.argv))
+	} else if name, err := os.Executable(); err == nil {
+		executableName = filepath.Base(name)
+	}
+
+	fmt.Printf("usage: %s [options] <mountpoint>\n\n", executableName)
+
+	fmt.Println("Filesystem options:")
+	fmt.Println("    -o source=/data/media  source directory to be mounted")
+	fmt.Println("    -o setuid=1023         uid to run as when starting as root")
+	fmt.Println("    -o setgid=1023         gid to run as when starting as root")
+
+	fmt.Println("\nFUSE options:")
+	C.fuse_cmdline_help()
+	C.fuse_lib_help(args)
+}
+
+// parseOpts parses fuse options via fuse_opt_parse.
+func parseOpts(args *fuseArgs, setup *setupState, log *log.Logger) (ok bool) {
+	var unsafeOpts struct {
+		// Pathname to writable source directory.
+		source *C.char
+
+		// Whether to create source directory as root.
+		mkdir C.int
+
+		// Decimal string representation of uid to set when running as root.
+		setuid *C.char
+		// Decimal string representation of gid to set when running as root.
+		setgid *C.char
+
+		// Decimal string representation of open file descriptor to read
+		// setupState from.
+		//
+		// This is an internal detail for containerisation and must not be
+		// specified directly.
+		setup *C.char
+	}
+
+	if C.fuse_opt_parse(args, unsafe.Pointer(&unsafeOpts), &[]C.struct_fuse_opt{
+		{templ: C.CString("source=%s"), offset: C.ulong(unsafe.Offsetof(unsafeOpts.source)), value: 0},
+		{templ: C.CString("mkdir"), offset: C.ulong(unsafe.Offsetof(unsafeOpts.mkdir)), value: 1},
+		{templ: C.CString("setuid=%s"), offset: C.ulong(unsafe.Offsetof(unsafeOpts.setuid)), value: 0},
+		{templ: C.CString("setgid=%s"), offset: C.ulong(unsafe.Offsetof(unsafeOpts.setgid)), value: 0},
+
+		{templ: C.CString("setup=%s"), offset: C.ulong(unsafe.Offsetof(unsafeOpts.setup)), value: 0},
+
+		C._FUSE_OPT_END(),
+	}[0], nil) == -1 {
+		return false
+	}
+
+	if unsafeOpts.source != nil {
+		defer C.free(unsafe.Pointer(unsafeOpts.source))
+	}
+	if unsafeOpts.setuid != nil {
+		defer C.free(unsafe.Pointer(unsafeOpts.setuid))
+	}
+	if unsafeOpts.setgid != nil {
+		defer C.free(unsafe.Pointer(unsafeOpts.setgid))
+	}
+
+	if unsafeOpts.setup != nil {
+		defer C.free(unsafe.Pointer(unsafeOpts.setup))
+
+		if v, err := strconv.Atoi(C.GoString(unsafeOpts.setup)); err != nil || v < 3 {
+			log.Println("invalid value for option setup")
+			return false
+		} else {
+			r := os.NewFile(uintptr(v), "setup")
+			defer func() {
+				if err = r.Close(); err != nil {
+					log.Println(err)
+				}
+			}()
+			if err = gob.NewDecoder(r).Decode(setup); err != nil {
+				log.Println(err)
+				return false
+			}
+		}
+		if setup.Fuse < 3 {
+			log.Println("invalid file descriptor", setup.Fuse)
+			return false
+		}
+		return true
+	}
+
+	if unsafeOpts.source == nil {
+		showHelp(args)
+		return false
+	} else if a, err := check.NewAbs(C.GoString(unsafeOpts.source)); err != nil {
+		log.Println(err)
+		return false
+	} else {
+		setup.Source = a
+	}
+	setup.mkdir = unsafeOpts.mkdir != 0
+
+	if unsafeOpts.setuid == nil {
+		setup.Setuid = -1
+	} else if v, err := strconv.Atoi(C.GoString(unsafeOpts.setuid)); err != nil || v <= 0 {
+		log.Println("invalid value for option setuid")
+		return false
+	} else {
+		setup.Setuid = v
+	}
+	if unsafeOpts.setgid == nil {
+		setup.Setgid = -1
+	} else if v, err := strconv.Atoi(C.GoString(unsafeOpts.setgid)); err != nil || v <= 0 {
+		log.Println("invalid value for option setgid")
+		return false
+	} else {
+		setup.Setgid = v
+	}
+
+	return true
+}
+
+// copyArgs returns a heap allocated copy of an argument slice in fuse_args
+// representation.
+func copyArgs(s ...string) fuseArgs {
+	if len(s) == 0 {
+		return fuseArgs{argc: 0, argv: nil, allocated: 0}
+	}
+	args := unsafe.Slice((**C.char)(C.malloc(C.size_t(uintptr(len(s))*unsafe.Sizeof(s[0])))), len(s))
+	for i, arg := range s {
+		args[i] = C.CString(arg)
+	}
+	return fuseArgs{argc: C.int(len(s)), argv: &args[0], allocated: 1}
+}
+
+// freeArgs frees the contents of argument list.
+func freeArgs(args *fuseArgs) { C.fuse_opt_free_args(args) }
+
+// unsafeAddArgument adds an argument to fuseArgs via fuse_opt_add_arg.
+//
+// The last byte of arg must be 0.
+func unsafeAddArgument(args *fuseArgs, arg string) {
+	C.fuse_opt_add_arg(args, (*C.char)(unsafe.Pointer(unsafe.StringData(arg))))
+}
+
+func _main(s ...string) (exitCode int) {
+	msg := message.New(log.Default())
+	container.TryArgv0(msg)
+	runtime.LockOSThread()
+
+	// don't mask creation mode, kernel already did that
+	syscall.Umask(0)
+
+	var pinner runtime.Pinner
+	defer pinner.Unpin()
+
+	args := copyArgs(s...)
+	defer freeArgs(&args)
+
+	// this causes the kernel to enforce access control based on struct stat
+	// populated by sharefs_getattr
+	unsafeAddArgument(&args, "-odefault_permissions\x00")
+
+	var priv C.struct_sharefs_private
+	pinner.Pin(&priv)
+	var setup setupState
+	priv.setup = C.uintptr_t(cgo.NewHandle(&setup))
+	defer destroySetup(unsafe.Pointer(&priv))
+
+	var opts C.struct_fuse_cmdline_opts
+	if C.fuse_parse_cmdline(&args, &opts) != 0 {
+		return 1
+	}
+	if opts.mountpoint != nil {
+		defer C.free(unsafe.Pointer(opts.mountpoint))
+	}
+
+	if opts.show_version != 0 {
+		fmt.Println("hakurei version", info.Version())
+		fmt.Println("FUSE library version", C.GoString(C.fuse_pkgversion()))
+		C.fuse_lowlevel_version()
+		return 0
+	}
+
+	if opts.show_help != 0 {
+		showHelp(&args)
+		return 0
+	} else if opts.mountpoint == nil {
+		log.Println("no mountpoint specified")
+		return 2
+	} else {
+		// hack to keep fuse_parse_cmdline happy in the container
+		mountpoint := C.GoString(opts.mountpoint)
+		pathnameArg := -1
+		for i, arg := range s {
+			if arg == mountpoint {
+				pathnameArg = i
+				break
+			}
+		}
+		if pathnameArg < 0 {
+			log.Println("mountpoint must be absolute")
+			return 2
+		}
+		s[pathnameArg] = container.Nonexistent
+	}
+
+	if !parseOpts(&args, &setup, msg.GetLogger()) {
+		return 1
+	}
+	asRoot := os.Geteuid() == 0
+
+	if asRoot {
+		if setup.Setuid <= 0 || setup.Setgid <= 0 {
+			log.Println("setuid and setgid must not be 0")
+			return 1
+		}
+
+		if setup.Fuse >= 3 {
+			log.Println("filesystem daemon must not run as root")
+			return 1
+		}
+
+		if setup.mkdir {
+			if err := os.MkdirAll(setup.Source.String(), 0700); err != nil {
+				if !errors.Is(err, os.ErrExist) {
+					log.Println(err)
+					return 1
+				}
+				// skip setup for existing source directory
+			} else if err = os.Chown(setup.Source.String(), setup.Setuid, setup.Setgid); err != nil {
+				log.Println(err)
+				return 1
+			}
+		}
+	} else if setup.Fuse < 3 && (setup.Setuid > 0 || setup.Setgid > 0) {
+		log.Println("setuid and setgid has no effect when not starting as root")
+		return 1
+	} else if setup.mkdir {
+		log.Println("mkdir has no effect when not starting as root")
+		return 1
+	}
+
+	op := C.struct_fuse_operations{
+		init:    closure(C.sharefs_init),
+		destroy: closure(C.sharefs_destroy),
+
+		// implemented in fuse-helper.c
+		getattr:  closure(C.sharefs_getattr),
+		readdir:  closure(C.sharefs_readdir),
+		mkdir:    closure(C.sharefs_mkdir),
+		unlink:   closure(C.sharefs_unlink),
+		rmdir:    closure(C.sharefs_rmdir),
+		rename:   closure(C.sharefs_rename),
+		truncate: closure(C.sharefs_truncate),
+		utimens:  closure(C.sharefs_utimens),
+		create:   closure(C.sharefs_create),
+		open:     closure(C.sharefs_open),
+		read:     closure(C.sharefs_read),
+		write:    closure(C.sharefs_write),
+		statfs:   closure(C.sharefs_statfs),
+		release:  closure(C.sharefs_release),
+		fsync:    closure(C.sharefs_fsync),
+	}
+
+	fuse := C.fuse_new_fn(&args, &op, C.size_t(unsafe.Sizeof(op)), unsafe.Pointer(&priv))
+	if fuse == nil {
+		return 3
+	}
+	defer C.fuse_destroy(fuse)
+	se := C.fuse_get_session(fuse)
+
+	if setup.Fuse < 3 {
+		// unconfined, set up mount point and container
+		if C.fuse_mount(fuse, opts.mountpoint) != 0 {
+			return 4
+		}
+		// unmounted by initial process
+		defer func() {
+			if exitCode == 5 {
+				C.fuse_unmount(fuse)
+			}
+		}()
+
+		if asRoot {
+			if err := syscall.Setresgid(setup.Setgid, setup.Setgid, setup.Setgid); err != nil {
+				log.Printf("cannot set gid: %v", err)
+				return 5
+			}
+			if err := syscall.Setgroups(nil); err != nil {
+				log.Printf("cannot set supplementary groups: %v", err)
+				return 5
+			}
+			if err := syscall.Setresuid(setup.Setuid, setup.Setuid, setup.Setuid); err != nil {
+				log.Printf("cannot set uid: %v", err)
+				return 5
+			}
+		}
+
+		msg.SwapVerbose(opts.debug != 0)
+		ctx := context.Background()
+		if opts.foreground != 0 {
+			c, cancel := signal.NotifyContext(ctx, syscall.SIGINT, syscall.SIGTERM)
+			defer cancel()
+			ctx = c
+		}
+		z := container.New(ctx, msg)
+		z.AllowOrphan = opts.foreground == 0
+		z.Env = os.Environ()
+
+		// keep fuse_parse_cmdline happy in the container
+		z.Tmpfs(check.MustAbs(container.Nonexistent), 1<<10, 0755)
+
+		z.Path = fhs.AbsProcSelfExe
+		z.Args = s
+		z.ForwardCancel = true
+		z.SeccompPresets |= std.PresetStrict
+		z.ParentPerm = 0700
+		z.Bind(setup.Source, setup.Source, std.BindWritable)
+		if !z.AllowOrphan {
+			z.WaitDelay = hst.WaitDelayMax
+			z.Stdin, z.Stdout, z.Stderr = os.Stdin, os.Stdout, os.Stderr
+		}
+		z.Bind(z.Path, z.Path, 0)
+		setup.Fuse = int(proc.ExtraFileSlice(
+			&z.ExtraFiles,
+			os.NewFile(uintptr(C.fuse_session_fd(se)), "fuse"),
+		))
+
+		var setupPipe [2]*os.File
+		if r, w, err := os.Pipe(); err != nil {
+			log.Println(err)
+			return 5
+		} else {
+			z.Args = append(z.Args, "-osetup="+strconv.Itoa(3+len(z.ExtraFiles)))
+			z.ExtraFiles = append(z.ExtraFiles, r)
+			setupPipe[0], setupPipe[1] = r, w
+		}
+
+		if err := z.Start(); err != nil {
+			if m, ok := message.GetMessage(err); ok {
+				log.Println(m)
+			} else {
+				log.Println(err)
+			}
+			return 5
+		}
+		if err := setupPipe[0].Close(); err != nil {
+			log.Println(err)
+		}
+		if err := z.Serve(); err != nil {
+			if m, ok := message.GetMessage(err); ok {
+				log.Println(m)
+			} else {
+				log.Println(err)
+			}
+			return 5
+		}
+
+		if err := gob.NewEncoder(setupPipe[1]).Encode(&setup); err != nil {
+			log.Println(err)
+			return 5
+		} else if err = setupPipe[1].Close(); err != nil {
+			log.Println(err)
+		}
+
+		if !z.AllowOrphan {
+			if err := z.Wait(); err != nil {
+				var exitError *exec.ExitError
+				if !errors.As(err, &exitError) || exitError == nil {
+					log.Println(err)
+					return 5
+				}
+				switch code := exitError.ExitCode(); syscall.Signal(code & 0x7f) {
+				case syscall.SIGINT:
+				case syscall.SIGTERM:
+
+				default:
+					return code
+				}
+			}
+		}
+		return 0
+	} else { // confined
+		C.free(unsafe.Pointer(opts.mountpoint))
+		// must be heap allocated
+		opts.mountpoint = C.CString("/dev/fd/" + strconv.Itoa(setup.Fuse))
+
+		if err := os.Chdir("/"); err != nil {
+			log.Println(err)
+		}
+	}
+
+	if C.fuse_mount(fuse, opts.mountpoint) != 0 {
+		return 4
+	}
+	defer C.fuse_unmount(fuse)
+
+	if C.fuse_set_signal_handlers(se) != 0 {
+		return 6
+	}
+	defer C.fuse_remove_signal_handlers(se)
+
+	if opts.singlethread != 0 {
+		if C.fuse_loop(fuse) != 0 {
+			return 8
+		}
+	} else {
+		loopConfig := C.fuse_loop_cfg_create()
+		if loopConfig == nil {
+			return 7
+		}
+		defer C.fuse_loop_cfg_destroy(loopConfig)
+
+		C.fuse_loop_cfg_set_clone_fd(loopConfig, C.uint(opts.clone_fd))
+
+		C.fuse_loop_cfg_set_idle_threads(loopConfig, opts.max_idle_threads)
+		C.fuse_loop_cfg_set_max_threads(loopConfig, opts.max_threads)
+		if C.fuse_loop_mt(fuse, loopConfig) != 0 {
+			return 8
+		}
+	}
+
+	if setup.initFailed {
+		return 1
+	}
+	return 0
+}

cmd/sharefs/fuse_test.go

@@ -0,0 +1,113 @@
+package main
+
+import (
+	"bytes"
+	"log"
+	"reflect"
+	"testing"
+
+	"hakurei.app/check"
+)
+
+func TestParseOpts(t *testing.T) {
+	t.Parallel()
+
+	testCases := []struct {
+		name    string
+		args    []string
+		want    setupState
+		wantLog string
+		wantOk  bool
+	}{
+		{"zero length", []string{}, setupState{}, "", false},
+
+		{"not absolute", []string{"sharefs",
+			"-o", "source=nonexistent",
+			"-o", "setuid=1023",
+			"-o", "setgid=1023",
+		}, setupState{}, "sharefs: path \"nonexistent\" is not absolute\n", false},
+
+		{"not specified", []string{"sharefs",
+			"-o", "setuid=1023",
+			"-o", "setgid=1023",
+		}, setupState{}, "", false},
+
+		{"invalid setuid", []string{"sharefs",
+			"-o", "source=/proc/nonexistent",
+			"-o", "setuid=ff",
+			"-o", "setgid=1023",
+		}, setupState{
+			Source: check.MustAbs("/proc/nonexistent"),
+		}, "sharefs: invalid value for option setuid\n", false},
+
+		{"invalid setgid", []string{"sharefs",
+			"-o", "source=/proc/nonexistent",
+			"-o", "setuid=1023",
+			"-o", "setgid=ff",
+		}, setupState{
+			Source: check.MustAbs("/proc/nonexistent"),
+			Setuid: 1023,
+		}, "sharefs: invalid value for option setgid\n", false},
+
+		{"simple", []string{"sharefs",
+			"-o", "source=/proc/nonexistent",
+		}, setupState{
+			Source: check.MustAbs("/proc/nonexistent"),
+			Setuid: -1,
+			Setgid: -1,
+		}, "", true},
+
+		{"root", []string{"sharefs",
+			"-o", "source=/proc/nonexistent",
+			"-o", "setuid=1023",
+			"-o", "setgid=1023",
+		}, setupState{
+			Source: check.MustAbs("/proc/nonexistent"),
+			Setuid: 1023,
+			Setgid: 1023,
+		}, "", true},
+
+		{"setuid", []string{"sharefs",
+			"-o", "source=/proc/nonexistent",
+			"-o", "setuid=1023",
+		}, setupState{
+			Source: check.MustAbs("/proc/nonexistent"),
+			Setuid: 1023,
+			Setgid: -1,
+		}, "", true},
+
+		{"setgid", []string{"sharefs",
+			"-o", "source=/proc/nonexistent",
+			"-o", "setgid=1023",
+		}, setupState{
+			Source: check.MustAbs("/proc/nonexistent"),
+			Setuid: -1,
+			Setgid: 1023,
+		}, "", true},
+	}
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			t.Parallel()
+
+			var (
+				got setupState
+				buf bytes.Buffer
+			)
+			args := copyArgs(tc.args...)
+			defer freeArgs(&args)
+			unsafeAddArgument(&args, "-odefault_permissions\x00")
+
+			if ok := parseOpts(&args, &got, log.New(&buf, "sharefs: ", 0)); ok != tc.wantOk {
+				t.Errorf("parseOpts: ok = %v, want %v", ok, tc.wantOk)
+			}
+
+			if !reflect.DeepEqual(&got, &tc.want) {
+				t.Errorf("parseOpts: setup = %#v, want %#v", got, tc.want)
+			}
+
+			if buf.String() != tc.wantLog {
+				t.Errorf("parseOpts: log =\n%s\nwant\n%s", buf.String(), tc.wantLog)
+			}
+		})
+	}
+}

cmd/sharefs/main.go

@@ -0,0 +1,38 @@
+// The sharefs FUSE filesystem is a permissionless shared filesystem.
+//
+// This filesystem is the primary means of file sharing between hakurei
+// application containers. It serves the same purpose in Rosa OS as /sdcard
+// does in AOSP.
+//
+// See help message for all available options.
+package main
+
+import (
+	"log"
+	"os"
+	"slices"
+)
+
+// sharefsName is the prefix used by log.std in the sharefs process.
+const sharefsName = "sharefs"
+
+// handleMountArgs returns an alternative, libfuse-compatible args slice for
+// args passed by mount -t fuse.sharefs [options] sharefs <mountpoint>.
+//
+// In this case, args always has a length of 5 with index 0 being what comes
+// after "fuse." in the filesystem type, 1 is the uninterpreted string passed
+// to mount (sharefsName is used as the magic string to enable this hack),
+// 2 is passed through to libfuse as mountpoint, and 3 is always "-o".
+func handleMountArgs(args []string) []string {
+	if len(args) == 5 && args[1] == sharefsName && args[3] == "-o" {
+		return []string{sharefsName, args[2], "-o", args[4]}
+	}
+	return slices.Clone(args)
+}
+
+func main() {
+	log.SetFlags(0)
+	log.SetPrefix(sharefsName + ": ")
+
+	os.Exit(_main(handleMountArgs(os.Args)...))
+}

cmd/sharefs/main_test.go

@@ -0,0 +1,29 @@
+package main
+
+import (
+	"slices"
+	"testing"
+)
+
+func TestHandleMountArgs(t *testing.T) {
+	t.Parallel()
+
+	testCases := []struct {
+		name string
+		args []string
+		want []string
+	}{
+		{"nil", nil, nil},
+		{"passthrough", []string{"sharefs", "-V"}, []string{"sharefs", "-V"}},
+		{"replace", []string{"/sbin/sharefs", "sharefs", "/sdcard", "-o", "rw"}, []string{"sharefs", "/sdcard", "-o", "rw"}},
+	}
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			t.Parallel()
+
+			if got := handleMountArgs(tc.args); !slices.Equal(got, tc.want) {
+				t.Errorf("handleMountArgs: %q, want %q", got, tc.want)
+			}
+		})
+	}
+}

cmd/sharefs/test/configuration.nix

@@ -0,0 +1,44 @@
+{ pkgs, ... }:
+{
+  users.users = {
+    alice = {
+      isNormalUser = true;
+      description = "Alice Foobar";
+      password = "foobar";
+      uid = 1000;
+    };
+  };
+
+  home-manager.users.alice.home.stateVersion = "24.11";
+
+  # Automatically login on tty1 as a normal user:
+  services.getty.autologinUser = "alice";
+
+  environment = {
+    # For benchmarking sharefs:
+    systemPackages = [ pkgs.fsmark ];
+  };
+
+  virtualisation = {
+    # Hopefully reduces spurious test failures:
+    memorySize = if pkgs.stdenv.hostPlatform.is32bit then 2046 else 8192;
+
+    diskSize = 6 * 1024;
+
+    qemu.options = [
+      # Increase test performance:
+      "-smp 16"
+    ];
+  };
+
+  environment.hakurei = rec {
+    enable = true;
+    stateDir = "/var/lib/hakurei";
+    sharefs.source = "${stateDir}/sdcard";
+    users.alice = 0;
+
+    extraHomeConfig = {
+      home.stateVersion = "23.05";
+    };
+  };
+}

cmd/sharefs/test/default.nix

@@ -0,0 +1,44 @@
+{
+  testers,
+
+  system,
+  self,
+}:
+testers.nixosTest {
+  name = "sharefs";
+  nodes.machine =
+    { options, pkgs, ... }:
+    let
+      fhs =
+        let
+          hakurei = options.environment.hakurei.package.default;
+        in
+        pkgs.buildFHSEnv {
+          pname = "hakurei-fhs";
+          inherit (hakurei) version;
+          targetPkgs = _: hakurei.targetPkgs;
+          extraOutputsToInstall = [ "dev" ];
+          profile = ''
+            export PKG_CONFIG_PATH="/usr/share/pkgconfig:$PKG_CONFIG_PATH"
+          '';
+        };
+    in
+    {
+      environment.systemPackages = [
+        # For go tests:
+        (pkgs.writeShellScriptBin "sharefs-workload-hakurei-tests" ''
+          cp -r "${self.packages.${system}.hakurei.src}" "/sdcard/hakurei" && cd "/sdcard/hakurei"
+          ${fhs}/bin/hakurei-fhs -c 'ROSA_SKIP_BINFMT=1 CC="clang -O3 -Werror" go test ./...'
+        '')
+      ];
+
+      imports = [
+        ./configuration.nix
+
+        self.nixosModules.hakurei
+        self.inputs.home-manager.nixosModules.home-manager
+      ];
+    };
+
+  testScript = builtins.readFile ./test.py;
+}

cmd/sharefs/test/raceattr.go

@@ -0,0 +1,122 @@
+//go:build raceattr
+
+// The raceattr program reproduces vfs inode file attribute race.
+//
+// Even though libfuse high-level API presents the address of a struct stat
+// alongside struct fuse_context, file attributes are actually inherent to the
+// inode, instead of the specific call from userspace. The kernel implementation
+// in fs/fuse/xattr.c appears to make stale data in the inode (set by a previous
+// call) impossible or very unlikely to reach userspace via the stat family of
+// syscalls. However, when using default_permissions to have the VFS check
+// permissions, this race still happens, despite the resulting struct stat being
+// correct when overriding the check via capabilities otherwise.
+//
+// This program reproduces the failure, but because of its continuous nature, it
+// is provided independent of the vm integration test suite.
+package main
+
+import (
+	"context"
+	"flag"
+	"log"
+	"os"
+	"os/signal"
+	"runtime"
+	"sync"
+	"sync/atomic"
+	"syscall"
+)
+
+func newStatAs(
+	ctx context.Context, cancel context.CancelFunc,
+	n *atomic.Uint64, ok *atomic.Bool,
+	uid uint32, pathname string,
+	continuous bool,
+) func() {
+	return func() {
+		runtime.LockOSThread()
+		defer cancel()
+
+		if _, _, errno := syscall.Syscall(
+			syscall.SYS_SETUID, uintptr(uid),
+			0, 0,
+		); errno != 0 {
+			cancel()
+			log.Printf("cannot set uid to %d: %s", uid, errno)
+		}
+
+		var stat syscall.Stat_t
+		for {
+			if ctx.Err() != nil {
+				return
+			}
+
+			if err := syscall.Lstat(pathname, &stat); err != nil {
+				// SHAREFS_PERM_DIR not world executable, or
+				// SHAREFS_PERM_REG not world readable
+				if !continuous {
+					cancel()
+				}
+				ok.Store(true)
+				log.Printf("uid %d: %v", uid, err)
+			} else if stat.Uid != uid {
+				// appears to be unreachable
+				if !continuous {
+					cancel()
+				}
+				ok.Store(true)
+				log.Printf("got uid %d instead of %d", stat.Uid, uid)
+			}
+			n.Add(1)
+		}
+	}
+}
+
+func main() {
+	log.SetFlags(0)
+	log.SetPrefix("raceattr: ")
+
+	p := flag.String("target", "/sdcard/raceattr", "pathname of test file")
+	u0 := flag.Int("uid0", 1<<10-1, "first uid")
+	u1 := flag.Int("uid1", 1<<10-2, "second uid")
+	count := flag.Int("count", 1, "threads per uid")
+	continuous := flag.Bool("continuous", false, "keep running even after reproduce")
+	flag.Parse()
+
+	if os.Geteuid() != 0 {
+		log.Fatal("this program must run as root")
+	}
+
+	ctx, cancel := signal.NotifyContext(
+		context.Background(),
+		syscall.SIGINT,
+		syscall.SIGTERM,
+		syscall.SIGHUP,
+	)
+
+	if err := os.WriteFile(*p, nil, 0); err != nil {
+		log.Fatal(err)
+	}
+
+	var (
+		wg sync.WaitGroup
+
+		n  atomic.Uint64
+		ok atomic.Bool
+	)
+
+	if *count < 1 {
+		*count = 1
+	}
+	for range *count {
+		wg.Go(newStatAs(ctx, cancel, &n, &ok, uint32(*u0), *p, *continuous))
+		if *u1 >= 0 {
+			wg.Go(newStatAs(ctx, cancel, &n, &ok, uint32(*u1), *p, *continuous))
+		}
+	}
+
+	wg.Wait()
+	if !*continuous && ok.Load() {
+		log.Printf("reproduced after %d calls", n.Load())
+	}
+}

cmd/sharefs/test/test.py

@@ -0,0 +1,60 @@
+start_all()
+machine.wait_for_unit("multi-user.target")
+
+# To check sharefs version:
+print(machine.succeed("sharefs -V"))
+
+# Make sure sharefs started:
+machine.wait_for_unit("sdcard.mount")
+
+machine.succeed("mkdir /mnt")
+def check_bad_opts_output(opts, want, source="/etc", privileged=False):
+    output = machine.fail(("" if privileged else "sudo -u alice -i ") + f"sharefs -f -o source={source},{opts} /mnt 2>&1")
+    if output != want:
+        raise Exception(f"unexpected output: {output}")
+
+# Malformed setuid/setgid representation:
+check_bad_opts_output("setuid=ff", "sharefs: invalid value for option setuid\n")
+check_bad_opts_output("setgid=ff", "sharefs: invalid value for option setgid\n")
+
+# Bounds check for setuid/setgid:
+check_bad_opts_output("setuid=0", "sharefs: invalid value for option setuid\n")
+check_bad_opts_output("setgid=0", "sharefs: invalid value for option setgid\n")
+check_bad_opts_output("setuid=-1", "sharefs: invalid value for option setuid\n")
+check_bad_opts_output("setgid=-1", "sharefs: invalid value for option setgid\n")
+
+# Non-root setuid/setgid:
+check_bad_opts_output("setuid=1023", "sharefs: setuid and setgid has no effect when not starting as root\n")
+check_bad_opts_output("setgid=1023", "sharefs: setuid and setgid has no effect when not starting as root\n")
+check_bad_opts_output("setuid=1023,setgid=1023", "sharefs: setuid and setgid has no effect when not starting as root\n")
+check_bad_opts_output("mkdir", "sharefs: mkdir has no effect when not starting as root\n")
+
+# Starting as root without setuid/setgid:
+check_bad_opts_output("allow_other", "sharefs: setuid and setgid must not be 0\n", privileged=True)
+check_bad_opts_output("setuid=1023", "sharefs: setuid and setgid must not be 0\n", privileged=True)
+check_bad_opts_output("setgid=1023", "sharefs: setuid and setgid must not be 0\n", privileged=True)
+
+# Make sure nothing actually got mounted:
+machine.fail("umount /mnt")
+machine.succeed("rmdir /mnt")
+
+# Unprivileged mount/unmount:
+machine.succeed("sudo -u alice -i mkdir /home/alice/{sdcard,persistent}")
+machine.succeed("sudo -u alice -i sharefs -o source=/home/alice/persistent /home/alice/sdcard")
+machine.succeed("sudo -u alice -i touch /home/alice/sdcard/check")
+machine.succeed("sudo -u alice -i umount /home/alice/sdcard")
+machine.succeed("sudo -u alice -i rm /home/alice/persistent/check")
+machine.succeed("sudo -u alice -i rmdir /home/alice/{sdcard,persistent}")
+
+# Benchmark sharefs:
+machine.succeed("fs_mark -v -d /sdcard/fs_mark -l /tmp/fs_log.txt")
+machine.copy_from_vm("/tmp/fs_log.txt", "")
+
+# Check permissions:
+machine.succeed("sudo -u sharefs touch /var/lib/hakurei/sdcard/fs_mark/.check")
+machine.succeed("sudo -u sharefs rm /var/lib/hakurei/sdcard/fs_mark/.check")
+machine.succeed("sudo -u alice rm -rf /sdcard/fs_mark")
+machine.fail("ls /var/lib/hakurei/sdcard/fs_mark")
+
+# Run hakurei tests on sharefs:
+machine.succeed("sudo -u alice -i sharefs-workload-hakurei-tests")

command/builder_test.go

@@ -7,6 +7,7 @@ import (
 )
 
 func TestBuild(t *testing.T) {
+	t.Parallel()
 	c := command.New(nil, nil, "test", nil)
 	stubHandler := func([]string) error { panic("unreachable") }
 

command/parse_test.go

@@ -14,6 +14,8 @@ import (
 )
 
 func TestParse(t *testing.T) {
+	t.Parallel()
+
 	testCases := []struct {
 		name      string
 		buildTree func(wout, wlog io.Writer) command.Command
@@ -251,6 +253,7 @@ Commands:
 	}
 	for _, tc := range testCases {
 		t.Run(tc.name, func(t *testing.T) {
+			t.Parallel()
 			wout, wlog := new(bytes.Buffer), new(bytes.Buffer)
 			c := tc.buildTree(wout, wlog)
 

command/unreachable_test.go

@@ -6,15 +6,19 @@ import (
 )
 
 func TestParseUnreachable(t *testing.T) {
+	t.Parallel()
+
 	// top level bypasses name matching and recursive calls to Parse
 	// returns when encountering zero-length args
 	t.Run("zero-length args", func(t *testing.T) {
+		t.Parallel()
 		defer checkRecover(t, "Parse", "attempted to parse with zero length args")
 		_ = newNode(panicWriter{}, nil, " ", " ").Parse(nil)
 	})
 
 	// top level must not have siblings
 	t.Run("toplevel siblings", func(t *testing.T) {
+		t.Parallel()
 		defer checkRecover(t, "Parse", "invalid toplevel state")
 		n := newNode(panicWriter{}, nil, " ", "")
 		n.append(newNode(panicWriter{}, nil, "  ", " "))
@@ -23,6 +27,7 @@ func TestParseUnreachable(t *testing.T) {
 
 	// a node with descendents must not have a direct handler
 	t.Run("sub handle conflict", func(t *testing.T) {
+		t.Parallel()
 		defer checkRecover(t, "Parse", "invalid subcommand tree state")
 		n := newNode(panicWriter{}, nil, " ", " ")
 		n.adopt(newNode(panicWriter{}, nil, " ", " "))
@@ -32,6 +37,7 @@ func TestParseUnreachable(t *testing.T) {
 
 	// this would only happen if a node was matched twice
 	t.Run("parsed flag set", func(t *testing.T) {
+		t.Parallel()
 		defer checkRecover(t, "Parse", "invalid set state")
 		n := newNode(panicWriter{}, nil, " ", "")
 		set := flag.NewFlagSet("parsed", flag.ContinueOnError)

container/autoetc.go

@@ -0,0 +1,74 @@
+package container
+
+import (
+	"encoding/gob"
+	"fmt"
+
+	"hakurei.app/check"
+	"hakurei.app/fhs"
+)
+
+func init() { gob.Register(new(AutoEtcOp)) }
+
+// Etc is a helper for appending [AutoEtcOp] to [Ops].
+func (f *Ops) Etc(host *check.Absolute, prefix string) *Ops {
+	e := &AutoEtcOp{prefix}
+	f.Mkdir(fhs.AbsEtc, 0755)
+	f.Bind(host, e.hostPath(), 0)
+	*f = append(*f, e)
+	return f
+}
+
+// AutoEtcOp expands host /etc into a toplevel symlink mirror with /etc semantics.
+//
+// This is not a generic setup op. It is implemented here to reduce ipc overhead.
+type AutoEtcOp struct{ Prefix string }
+
+func (e *AutoEtcOp) Valid() bool                                { return e != nil }
+func (e *AutoEtcOp) early(*setupState, syscallDispatcher) error { return nil }
+func (e *AutoEtcOp) apply(state *setupState, k syscallDispatcher) error {
+	if state.nonrepeatable&nrAutoEtc != 0 {
+		return OpRepeatError("autoetc")
+	}
+	state.nonrepeatable |= nrAutoEtc
+
+	const target = sysrootPath + fhs.Etc
+	rel := e.hostRel() + "/"
+
+	if err := k.mkdirAll(target, 0755); err != nil {
+		return err
+	}
+	if d, err := k.readdir(toSysroot(e.hostPath().String())); err != nil {
+		return err
+	} else {
+		for _, ent := range d {
+			n := ent.Name()
+			switch n {
+			case ".host", "passwd", "group":
+
+			case "mtab":
+				if err = k.symlink(fhs.Proc+"mounts", target+n); err != nil {
+					return err
+				}
+
+			default:
+				if err = k.symlink(rel+n, target+n); err != nil {
+					return err
+				}
+			}
+		}
+	}
+
+	return nil
+}
+func (e *AutoEtcOp) late(*setupState, syscallDispatcher) error { return nil }
+
+func (e *AutoEtcOp) hostPath() *check.Absolute { return fhs.AbsEtc.Append(e.hostRel()) }
+func (e *AutoEtcOp) hostRel() string           { return ".host/" + e.Prefix }
+
+func (e *AutoEtcOp) Is(op Op) bool {
+	ve, ok := op.(*AutoEtcOp)
+	return ok && e.Valid() && ve.Valid() && *e == *ve
+}
+func (*AutoEtcOp) prefix() (string, bool) { return "setting up", true }
+func (e *AutoEtcOp) String() string       { return fmt.Sprintf("auto etc %s", e.Prefix) }

container/autoetc_test.go

@@ -0,0 +1,297 @@
+package container
+
+import (
+	"errors"
+	"os"
+	"testing"
+
+	"hakurei.app/check"
+	"hakurei.app/internal/stub"
+)
+
+func TestAutoEtcOp(t *testing.T) {
+	t.Parallel()
+
+	t.Run("nonrepeatable", func(t *testing.T) {
+		t.Parallel()
+		wantErr := OpRepeatError("autoetc")
+		if err := (&AutoEtcOp{Prefix: "81ceabb30d37bbdb3868004629cb84e9"}).apply(&setupState{nonrepeatable: nrAutoEtc}, nil); !errors.Is(err, wantErr) {
+			t.Errorf("apply: error = %v, want %v", err, wantErr)
+		}
+	})
+
+	checkOpBehaviour(t, []opBehaviourTestCase{
+		{"mkdirAll", new(Params), &AutoEtcOp{
+			Prefix: "81ceabb30d37bbdb3868004629cb84e9",
+		}, nil, nil, []stub.Call{
+			call("mkdirAll", stub.ExpectArgs{"/sysroot/etc/", os.FileMode(0755)}, nil, stub.UniqueError(3)),
+		}, stub.UniqueError(3)},
+
+		{"readdir", new(Params), &AutoEtcOp{
+			Prefix: "81ceabb30d37bbdb3868004629cb84e9",
+		}, nil, nil, []stub.Call{
+			call("mkdirAll", stub.ExpectArgs{"/sysroot/etc/", os.FileMode(0755)}, nil, nil),
+			call("readdir", stub.ExpectArgs{"/sysroot/etc/.host/81ceabb30d37bbdb3868004629cb84e9"}, stubDir(), stub.UniqueError(2)),
+		}, stub.UniqueError(2)},
+
+		{"symlink", new(Params), &AutoEtcOp{
+			Prefix: "81ceabb30d37bbdb3868004629cb84e9",
+		}, nil, nil, []stub.Call{
+			call("mkdirAll", stub.ExpectArgs{"/sysroot/etc/", os.FileMode(0755)}, nil, nil),
+			call("readdir", stub.ExpectArgs{"/sysroot/etc/.host/81ceabb30d37bbdb3868004629cb84e9"}, stubDir(".host",
+				"alsa", "bash_logout", "bashrc", "binfmt.d", "dbus-1", "default", "dhcpcd.exit-hook", "fonts",
+				"fstab", "fuse.conf", "group", "host.conf", "hostname", "hosts", "hsurc", "inputrc", "issue", "kbd",
+				"locale.conf", "login.defs", "lsb-release", "lvm", "machine-id", "man_db.conf", "mdadm.conf",
+				"modprobe.d", "modules-load.d", "mtab", "nanorc", "netgroup", "nix", "nixos", "NIXOS", "nscd.conf",
+				"nsswitch.conf", "os-release", "pam", "pam.d", "passwd", "pipewire", "pki", "polkit-1", "profile",
+				"protocols", "resolv.conf", "resolvconf.conf", "rpc", "services", "set-environment", "shadow", "shells",
+				"ssh", "ssl", "static", "subgid", "subuid", "sudoers", "sway", "sysctl.d", "systemd", "terminfo",
+				"tmpfiles.d", "udev", "vconsole.conf", "X11", "xdg", "zoneinfo"), nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/alsa", "/sysroot/etc/alsa"}, nil, stub.UniqueError(1)),
+		}, stub.UniqueError(1)},
+
+		{"symlink mtab", new(Params), &AutoEtcOp{
+			Prefix: "81ceabb30d37bbdb3868004629cb84e9",
+		}, nil, nil, []stub.Call{
+			call("mkdirAll", stub.ExpectArgs{"/sysroot/etc/", os.FileMode(0755)}, nil, nil),
+			call("readdir", stub.ExpectArgs{"/sysroot/etc/.host/81ceabb30d37bbdb3868004629cb84e9"}, stubDir(".host",
+				"alsa", "bash_logout", "bashrc", "binfmt.d", "dbus-1", "default", "dhcpcd.exit-hook", "fonts",
+				"fstab", "fuse.conf", "group", "host.conf", "hostname", "hosts", "hsurc", "inputrc", "issue", "kbd",
+				"locale.conf", "login.defs", "lsb-release", "lvm", "machine-id", "man_db.conf", "mdadm.conf",
+				"modprobe.d", "modules-load.d", "mtab", "nanorc", "netgroup", "nix", "nixos", "NIXOS", "nscd.conf",
+				"nsswitch.conf", "os-release", "pam", "pam.d", "passwd", "pipewire", "pki", "polkit-1", "profile",
+				"protocols", "resolv.conf", "resolvconf.conf", "rpc", "services", "set-environment", "shadow", "shells",
+				"ssh", "ssl", "static", "subgid", "subuid", "sudoers", "sway", "sysctl.d", "systemd", "terminfo",
+				"tmpfiles.d", "udev", "vconsole.conf", "X11", "xdg", "zoneinfo"), nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/alsa", "/sysroot/etc/alsa"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/bash_logout", "/sysroot/etc/bash_logout"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/bashrc", "/sysroot/etc/bashrc"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/binfmt.d", "/sysroot/etc/binfmt.d"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/dbus-1", "/sysroot/etc/dbus-1"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/default", "/sysroot/etc/default"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/dhcpcd.exit-hook", "/sysroot/etc/dhcpcd.exit-hook"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/fonts", "/sysroot/etc/fonts"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/fstab", "/sysroot/etc/fstab"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/fuse.conf", "/sysroot/etc/fuse.conf"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/host.conf", "/sysroot/etc/host.conf"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/hostname", "/sysroot/etc/hostname"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/hosts", "/sysroot/etc/hosts"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/hsurc", "/sysroot/etc/hsurc"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/inputrc", "/sysroot/etc/inputrc"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/issue", "/sysroot/etc/issue"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/kbd", "/sysroot/etc/kbd"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/locale.conf", "/sysroot/etc/locale.conf"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/login.defs", "/sysroot/etc/login.defs"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/lsb-release", "/sysroot/etc/lsb-release"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/lvm", "/sysroot/etc/lvm"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/machine-id", "/sysroot/etc/machine-id"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/man_db.conf", "/sysroot/etc/man_db.conf"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/mdadm.conf", "/sysroot/etc/mdadm.conf"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/modprobe.d", "/sysroot/etc/modprobe.d"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/modules-load.d", "/sysroot/etc/modules-load.d"}, nil, nil),
+			call("symlink", stub.ExpectArgs{"/proc/mounts", "/sysroot/etc/mtab"}, nil, stub.UniqueError(0)),
+		}, stub.UniqueError(0)},
+
+		{"success nested", new(Params), &AutoEtcOp{
+			Prefix: "81ceabb30d37bbdb3868004629cb84e9",
+		}, nil, nil, []stub.Call{
+			call("mkdirAll", stub.ExpectArgs{"/sysroot/etc/", os.FileMode(0755)}, nil, nil),
+			call("readdir", stub.ExpectArgs{"/sysroot/etc/.host/81ceabb30d37bbdb3868004629cb84e9"}, stubDir(".host",
+				"alsa", "bash_logout", "bashrc", "binfmt.d", "dbus-1", "default", "dhcpcd.exit-hook", "fonts",
+				"fstab", "fuse.conf", "group", "host.conf", "hostname", "hosts", "hsurc", "inputrc", "issue", "kbd",
+				"locale.conf", "login.defs", "lsb-release", "lvm", "machine-id", "man_db.conf", "mdadm.conf",
+				"modprobe.d", "modules-load.d", "mtab", "nanorc", "netgroup", "nix", "nixos", "NIXOS", "nscd.conf",
+				"nsswitch.conf", "os-release", "pam", "pam.d", "passwd", "pipewire", "pki", "polkit-1", "profile",
+				"protocols", "resolv.conf", "resolvconf.conf", "rpc", "services", "set-environment", "shadow", "shells",
+				"ssh", "ssl", "static", "subgid", "subuid", "sudoers", "sway", "sysctl.d", "systemd", "terminfo",
+				"tmpfiles.d", "udev", "vconsole.conf", "X11", "xdg", "zoneinfo"), nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/alsa", "/sysroot/etc/alsa"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/bash_logout", "/sysroot/etc/bash_logout"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/bashrc", "/sysroot/etc/bashrc"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/binfmt.d", "/sysroot/etc/binfmt.d"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/dbus-1", "/sysroot/etc/dbus-1"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/default", "/sysroot/etc/default"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/dhcpcd.exit-hook", "/sysroot/etc/dhcpcd.exit-hook"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/fonts", "/sysroot/etc/fonts"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/fstab", "/sysroot/etc/fstab"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/fuse.conf", "/sysroot/etc/fuse.conf"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/host.conf", "/sysroot/etc/host.conf"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/hostname", "/sysroot/etc/hostname"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/hosts", "/sysroot/etc/hosts"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/hsurc", "/sysroot/etc/hsurc"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/inputrc", "/sysroot/etc/inputrc"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/issue", "/sysroot/etc/issue"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/kbd", "/sysroot/etc/kbd"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/locale.conf", "/sysroot/etc/locale.conf"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/login.defs", "/sysroot/etc/login.defs"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/lsb-release", "/sysroot/etc/lsb-release"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/lvm", "/sysroot/etc/lvm"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/machine-id", "/sysroot/etc/machine-id"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/man_db.conf", "/sysroot/etc/man_db.conf"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/mdadm.conf", "/sysroot/etc/mdadm.conf"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/modprobe.d", "/sysroot/etc/modprobe.d"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/modules-load.d", "/sysroot/etc/modules-load.d"}, nil, nil),
+			call("symlink", stub.ExpectArgs{"/proc/mounts", "/sysroot/etc/mtab"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/nanorc", "/sysroot/etc/nanorc"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/netgroup", "/sysroot/etc/netgroup"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/nix", "/sysroot/etc/nix"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/nixos", "/sysroot/etc/nixos"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/NIXOS", "/sysroot/etc/NIXOS"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/nscd.conf", "/sysroot/etc/nscd.conf"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/nsswitch.conf", "/sysroot/etc/nsswitch.conf"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/os-release", "/sysroot/etc/os-release"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/pam", "/sysroot/etc/pam"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/pam.d", "/sysroot/etc/pam.d"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/pipewire", "/sysroot/etc/pipewire"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/pki", "/sysroot/etc/pki"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/polkit-1", "/sysroot/etc/polkit-1"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/profile", "/sysroot/etc/profile"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/protocols", "/sysroot/etc/protocols"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/resolv.conf", "/sysroot/etc/resolv.conf"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/resolvconf.conf", "/sysroot/etc/resolvconf.conf"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/rpc", "/sysroot/etc/rpc"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/services", "/sysroot/etc/services"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/set-environment", "/sysroot/etc/set-environment"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/shadow", "/sysroot/etc/shadow"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/shells", "/sysroot/etc/shells"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/ssh", "/sysroot/etc/ssh"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/ssl", "/sysroot/etc/ssl"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/static", "/sysroot/etc/static"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/subgid", "/sysroot/etc/subgid"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/subuid", "/sysroot/etc/subuid"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/sudoers", "/sysroot/etc/sudoers"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/sway", "/sysroot/etc/sway"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/sysctl.d", "/sysroot/etc/sysctl.d"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/systemd", "/sysroot/etc/systemd"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/terminfo", "/sysroot/etc/terminfo"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/tmpfiles.d", "/sysroot/etc/tmpfiles.d"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/udev", "/sysroot/etc/udev"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/vconsole.conf", "/sysroot/etc/vconsole.conf"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/X11", "/sysroot/etc/X11"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/xdg", "/sysroot/etc/xdg"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/zoneinfo", "/sysroot/etc/zoneinfo"}, nil, nil),
+		}, nil},
+
+		{"success", new(Params), &AutoEtcOp{
+			Prefix: "81ceabb30d37bbdb3868004629cb84e9",
+		}, nil, nil, []stub.Call{
+			call("mkdirAll", stub.ExpectArgs{"/sysroot/etc/", os.FileMode(0755)}, nil, nil),
+			call("readdir", stub.ExpectArgs{"/sysroot/etc/.host/81ceabb30d37bbdb3868004629cb84e9"}, stubDir(
+				"alsa", "bash_logout", "bashrc", "binfmt.d", "dbus-1", "default", "dhcpcd.exit-hook", "fonts",
+				"fstab", "fuse.conf", "group", "host.conf", "hostname", "hosts", "hsurc", "inputrc", "issue", "kbd",
+				"locale.conf", "login.defs", "lsb-release", "lvm", "machine-id", "man_db.conf", "mdadm.conf",
+				"modprobe.d", "modules-load.d", "mtab", "nanorc", "netgroup", "nix", "nixos", "NIXOS", "nscd.conf",
+				"nsswitch.conf", "os-release", "pam", "pam.d", "passwd", "pipewire", "pki", "polkit-1", "profile",
+				"protocols", "resolv.conf", "resolvconf.conf", "rpc", "services", "set-environment", "shadow", "shells",
+				"ssh", "ssl", "static", "subgid", "subuid", "sudoers", "sway", "sysctl.d", "systemd", "terminfo",
+				"tmpfiles.d", "udev", "vconsole.conf", "X11", "xdg", "zoneinfo"), nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/alsa", "/sysroot/etc/alsa"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/bash_logout", "/sysroot/etc/bash_logout"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/bashrc", "/sysroot/etc/bashrc"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/binfmt.d", "/sysroot/etc/binfmt.d"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/dbus-1", "/sysroot/etc/dbus-1"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/default", "/sysroot/etc/default"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/dhcpcd.exit-hook", "/sysroot/etc/dhcpcd.exit-hook"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/fonts", "/sysroot/etc/fonts"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/fstab", "/sysroot/etc/fstab"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/fuse.conf", "/sysroot/etc/fuse.conf"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/host.conf", "/sysroot/etc/host.conf"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/hostname", "/sysroot/etc/hostname"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/hosts", "/sysroot/etc/hosts"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/hsurc", "/sysroot/etc/hsurc"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/inputrc", "/sysroot/etc/inputrc"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/issue", "/sysroot/etc/issue"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/kbd", "/sysroot/etc/kbd"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/locale.conf", "/sysroot/etc/locale.conf"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/login.defs", "/sysroot/etc/login.defs"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/lsb-release", "/sysroot/etc/lsb-release"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/lvm", "/sysroot/etc/lvm"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/machine-id", "/sysroot/etc/machine-id"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/man_db.conf", "/sysroot/etc/man_db.conf"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/mdadm.conf", "/sysroot/etc/mdadm.conf"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/modprobe.d", "/sysroot/etc/modprobe.d"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/modules-load.d", "/sysroot/etc/modules-load.d"}, nil, nil),
+			call("symlink", stub.ExpectArgs{"/proc/mounts", "/sysroot/etc/mtab"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/nanorc", "/sysroot/etc/nanorc"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/netgroup", "/sysroot/etc/netgroup"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/nix", "/sysroot/etc/nix"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/nixos", "/sysroot/etc/nixos"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/NIXOS", "/sysroot/etc/NIXOS"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/nscd.conf", "/sysroot/etc/nscd.conf"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/nsswitch.conf", "/sysroot/etc/nsswitch.conf"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/os-release", "/sysroot/etc/os-release"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/pam", "/sysroot/etc/pam"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/pam.d", "/sysroot/etc/pam.d"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/pipewire", "/sysroot/etc/pipewire"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/pki", "/sysroot/etc/pki"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/polkit-1", "/sysroot/etc/polkit-1"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/profile", "/sysroot/etc/profile"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/protocols", "/sysroot/etc/protocols"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/resolv.conf", "/sysroot/etc/resolv.conf"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/resolvconf.conf", "/sysroot/etc/resolvconf.conf"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/rpc", "/sysroot/etc/rpc"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/services", "/sysroot/etc/services"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/set-environment", "/sysroot/etc/set-environment"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/shadow", "/sysroot/etc/shadow"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/shells", "/sysroot/etc/shells"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/ssh", "/sysroot/etc/ssh"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/ssl", "/sysroot/etc/ssl"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/static", "/sysroot/etc/static"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/subgid", "/sysroot/etc/subgid"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/subuid", "/sysroot/etc/subuid"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/sudoers", "/sysroot/etc/sudoers"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/sway", "/sysroot/etc/sway"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/sysctl.d", "/sysroot/etc/sysctl.d"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/systemd", "/sysroot/etc/systemd"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/terminfo", "/sysroot/etc/terminfo"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/tmpfiles.d", "/sysroot/etc/tmpfiles.d"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/udev", "/sysroot/etc/udev"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/vconsole.conf", "/sysroot/etc/vconsole.conf"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/X11", "/sysroot/etc/X11"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/xdg", "/sysroot/etc/xdg"}, nil, nil),
+			call("symlink", stub.ExpectArgs{".host/81ceabb30d37bbdb3868004629cb84e9/zoneinfo", "/sysroot/etc/zoneinfo"}, nil, nil),
+		}, nil},
+	})
+
+	checkOpsValid(t, []opValidTestCase{
+		{"nil", (*AutoEtcOp)(nil), false},
+		{"zero", new(AutoEtcOp), true},
+		{"populated", &AutoEtcOp{Prefix: ":3"}, true},
+	})
+
+	checkOpsBuilder(t, []opsBuilderTestCase{
+		{"pd", new(Ops).Etc(check.MustAbs("/etc/"), "048090b6ed8f9ebb10e275ff5d8c0659"), Ops{
+			&MkdirOp{Path: check.MustAbs("/etc/"), Perm: 0755},
+			&BindMountOp{
+				Source: check.MustAbs("/etc/"),
+				Target: check.MustAbs("/etc/.host/048090b6ed8f9ebb10e275ff5d8c0659"),
+			},
+			&AutoEtcOp{Prefix: "048090b6ed8f9ebb10e275ff5d8c0659"},
+		}},
+	})
+
+	checkOpIs(t, []opIsTestCase{
+		{"zero", new(AutoEtcOp), new(AutoEtcOp), true},
+		{"differs", &AutoEtcOp{Prefix: "\x00"}, &AutoEtcOp{":3"}, false},
+		{"equals", &AutoEtcOp{Prefix: ":3"}, &AutoEtcOp{":3"}, true},
+	})
+
+	checkOpMeta(t, []opMetaTestCase{
+		{"etc", &AutoEtcOp{
+			Prefix: ":3",
+		}, "setting up", "auto etc :3"},
+	})
+
+	t.Run("host path rel", func(t *testing.T) {
+		t.Parallel()
+		op := &AutoEtcOp{Prefix: "048090b6ed8f9ebb10e275ff5d8c0659"}
+		wantHostPath := "/etc/.host/048090b6ed8f9ebb10e275ff5d8c0659"
+		wantHostRel := ".host/048090b6ed8f9ebb10e275ff5d8c0659"
+		if got := op.hostPath(); got.String() != wantHostPath {
+			t.Errorf("hostPath: %q, want %q", got, wantHostPath)
+		}
+		if got := op.hostRel(); got != wantHostRel {
+			t.Errorf("hostRel: %q, want %q", got, wantHostRel)
+		}
+	})
+}

container/autoroot.go

@@ -0,0 +1,100 @@
+package container
+
+import (
+	"encoding/gob"
+	"fmt"
+
+	"hakurei.app/check"
+	"hakurei.app/fhs"
+	"hakurei.app/message"
+)
+
+func init() { gob.Register(new(AutoRootOp)) }
+
+// Root is a helper for appending [AutoRootOp] to [Ops].
+func (f *Ops) Root(host *check.Absolute, flags int) *Ops {
+	*f = append(*f, &AutoRootOp{host, flags, nil})
+	return f
+}
+
+// AutoRootOp expands a directory into a toplevel bind mount mirror on container root.
+//
+// This is not a generic setup op. It is implemented here to reduce ipc overhead.
+type AutoRootOp struct {
+	Host *check.Absolute
+	// passed through to bindMount
+	Flags int
+
+	// obtained during early;
+	// these wrap the underlying Op because BindMountOp is relatively complex,
+	// so duplicating that code would be unwise
+	resolved []*BindMountOp
+}
+
+func (r *AutoRootOp) Valid() bool { return r != nil && r.Host != nil }
+
+func (r *AutoRootOp) early(state *setupState, k syscallDispatcher) error {
+	if d, err := k.readdir(r.Host.String()); err != nil {
+		return err
+	} else {
+		r.resolved = make([]*BindMountOp, 0, len(d))
+		for _, ent := range d {
+			name := ent.Name()
+			if IsAutoRootBindable(state, name) {
+				// careful: the Valid method is skipped, make sure this is always valid
+				op := &BindMountOp{
+					Source: r.Host.Append(name),
+					Target: fhs.AbsRoot.Append(name),
+					Flags:  r.Flags,
+				}
+				if err = op.early(state, k); err != nil {
+					return err
+				}
+				r.resolved = append(r.resolved, op)
+			}
+		}
+		return nil
+	}
+}
+
+func (r *AutoRootOp) apply(state *setupState, k syscallDispatcher) error {
+	if state.nonrepeatable&nrAutoRoot != 0 {
+		return OpRepeatError("autoroot")
+	}
+	state.nonrepeatable |= nrAutoRoot
+
+	for _, op := range r.resolved {
+		// these are exclusively BindMountOp, do not attempt to print identifying message
+		if err := op.apply(state, k); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+func (r *AutoRootOp) late(*setupState, syscallDispatcher) error { return nil }
+
+func (r *AutoRootOp) Is(op Op) bool {
+	vr, ok := op.(*AutoRootOp)
+	return ok && r.Valid() && vr.Valid() &&
+		r.Host.Is(vr.Host) &&
+		r.Flags == vr.Flags
+}
+func (*AutoRootOp) prefix() (string, bool) { return "setting up", true }
+func (r *AutoRootOp) String() string {
+	return fmt.Sprintf("auto root %q flags %#x", r.Host, r.Flags)
+}
+
+// IsAutoRootBindable returns whether a dir entry name is selected for AutoRoot.
+func IsAutoRootBindable(msg message.Msg, name string) bool {
+	switch name {
+	case "proc", "dev", "tmp", "mnt", "etc":
+
+	case "": // guard against accidentally binding /
+		// should be unreachable
+		msg.Verbose("got unexpected root entry")
+
+	default:
+		return true
+	}
+	return false
+}

container/autoroot_test.go

@@ -0,0 +1,214 @@
+package container
+
+import (
+	"errors"
+	"os"
+	"testing"
+
+	"hakurei.app/check"
+	"hakurei.app/container/std"
+	"hakurei.app/internal/stub"
+	"hakurei.app/message"
+)
+
+func TestAutoRootOp(t *testing.T) {
+	t.Run("nonrepeatable", func(t *testing.T) {
+		t.Parallel()
+		wantErr := OpRepeatError("autoroot")
+		if err := new(AutoRootOp).apply(&setupState{nonrepeatable: nrAutoRoot}, nil); !errors.Is(err, wantErr) {
+			t.Errorf("apply: error = %v, want %v", err, wantErr)
+		}
+	})
+
+	checkOpBehaviour(t, []opBehaviourTestCase{
+		{"readdir", &Params{ParentPerm: 0750}, &AutoRootOp{
+			Host:  check.MustAbs("/"),
+			Flags: std.BindWritable,
+		}, []stub.Call{
+			call("readdir", stub.ExpectArgs{"/"}, stubDir(), stub.UniqueError(2)),
+		}, stub.UniqueError(2), nil, nil},
+
+		{"early", &Params{ParentPerm: 0750}, &AutoRootOp{
+			Host:  check.MustAbs("/"),
+			Flags: std.BindWritable,
+		}, []stub.Call{
+			call("readdir", stub.ExpectArgs{"/"}, stubDir("bin", "dev", "etc", "home", "lib64",
+				"lost+found", "mnt", "nix", "proc", "root", "run", "srv", "sys", "tmp", "usr", "var"), nil),
+			call("evalSymlinks", stub.ExpectArgs{"/bin"}, "", stub.UniqueError(1)),
+		}, stub.UniqueError(1), nil, nil},
+
+		{"apply", &Params{ParentPerm: 0750}, &AutoRootOp{
+			Host:  check.MustAbs("/"),
+			Flags: std.BindWritable,
+		}, []stub.Call{
+			call("readdir", stub.ExpectArgs{"/"}, stubDir("bin", "dev", "etc", "home", "lib64",
+				"lost+found", "mnt", "nix", "proc", "root", "run", "srv", "sys", "tmp", "usr", "var"), nil),
+			call("evalSymlinks", stub.ExpectArgs{"/bin"}, "/usr/bin", nil),
+			call("evalSymlinks", stub.ExpectArgs{"/home"}, "/home", nil),
+			call("evalSymlinks", stub.ExpectArgs{"/lib64"}, "/lib64", nil),
+			call("evalSymlinks", stub.ExpectArgs{"/lost+found"}, "/lost+found", nil),
+			call("evalSymlinks", stub.ExpectArgs{"/nix"}, "/nix", nil),
+			call("evalSymlinks", stub.ExpectArgs{"/root"}, "/root", nil),
+			call("evalSymlinks", stub.ExpectArgs{"/run"}, "/run", nil),
+			call("evalSymlinks", stub.ExpectArgs{"/srv"}, "/srv", nil),
+			call("evalSymlinks", stub.ExpectArgs{"/sys"}, "/sys", nil),
+			call("evalSymlinks", stub.ExpectArgs{"/usr"}, "/usr", nil),
+			call("evalSymlinks", stub.ExpectArgs{"/var"}, "/var", nil),
+		}, nil, []stub.Call{
+			call("stat", stub.ExpectArgs{"/host/usr/bin"}, isDirFi(false), stub.UniqueError(0)),
+		}, stub.UniqueError(0)},
+
+		{"success pd", &Params{ParentPerm: 0750}, &AutoRootOp{
+			Host:  check.MustAbs("/"),
+			Flags: std.BindWritable,
+		}, []stub.Call{
+			call("readdir", stub.ExpectArgs{"/"}, stubDir("bin", "dev", "etc", "home", "lib64",
+				"lost+found", "mnt", "nix", "proc", "root", "run", "srv", "sys", "tmp", "usr", "var"), nil),
+			call("evalSymlinks", stub.ExpectArgs{"/bin"}, "/usr/bin", nil),
+			call("evalSymlinks", stub.ExpectArgs{"/home"}, "/home", nil),
+			call("evalSymlinks", stub.ExpectArgs{"/lib64"}, "/lib64", nil),
+			call("evalSymlinks", stub.ExpectArgs{"/lost+found"}, "/lost+found", nil),
+			call("evalSymlinks", stub.ExpectArgs{"/nix"}, "/nix", nil),
+			call("evalSymlinks", stub.ExpectArgs{"/root"}, "/root", nil),
+			call("evalSymlinks", stub.ExpectArgs{"/run"}, "/run", nil),
+			call("evalSymlinks", stub.ExpectArgs{"/srv"}, "/srv", nil),
+			call("evalSymlinks", stub.ExpectArgs{"/sys"}, "/sys", nil),
+			call("evalSymlinks", stub.ExpectArgs{"/usr"}, "/usr", nil),
+			call("evalSymlinks", stub.ExpectArgs{"/var"}, "/var", nil),
+		}, nil, []stub.Call{
+			call("stat", stub.ExpectArgs{"/host/usr/bin"}, isDirFi(true), nil), call("mkdirAll", stub.ExpectArgs{"/sysroot/bin", os.FileMode(0700)}, nil, nil), call("verbosef", stub.ExpectArgs{"mounting %q on %q flags %#x", []any{"/host/usr/bin", "/sysroot/bin", uintptr(0x4004)}}, nil, nil), call("bindMount", stub.ExpectArgs{"/host/usr/bin", "/sysroot/bin", uintptr(0x4004), false}, nil, nil),
+			call("stat", stub.ExpectArgs{"/host/home"}, isDirFi(true), nil), call("mkdirAll", stub.ExpectArgs{"/sysroot/home", os.FileMode(0700)}, nil, nil), call("verbosef", stub.ExpectArgs{"mounting %q flags %#x", []any{"/sysroot/home", uintptr(0x4004)}}, nil, nil), call("bindMount", stub.ExpectArgs{"/host/home", "/sysroot/home", uintptr(0x4004), false}, nil, nil),
+			call("stat", stub.ExpectArgs{"/host/lib64"}, isDirFi(true), nil), call("mkdirAll", stub.ExpectArgs{"/sysroot/lib64", os.FileMode(0700)}, nil, nil), call("verbosef", stub.ExpectArgs{"mounting %q flags %#x", []any{"/sysroot/lib64", uintptr(0x4004)}}, nil, nil), call("bindMount", stub.ExpectArgs{"/host/lib64", "/sysroot/lib64", uintptr(0x4004), false}, nil, nil),
+			call("stat", stub.ExpectArgs{"/host/lost+found"}, isDirFi(true), nil), call("mkdirAll", stub.ExpectArgs{"/sysroot/lost+found", os.FileMode(0700)}, nil, nil), call("verbosef", stub.ExpectArgs{"mounting %q flags %#x", []any{"/sysroot/lost+found", uintptr(0x4004)}}, nil, nil), call("bindMount", stub.ExpectArgs{"/host/lost+found", "/sysroot/lost+found", uintptr(0x4004), false}, nil, nil),
+			call("stat", stub.ExpectArgs{"/host/nix"}, isDirFi(true), nil), call("mkdirAll", stub.ExpectArgs{"/sysroot/nix", os.FileMode(0700)}, nil, nil), call("verbosef", stub.ExpectArgs{"mounting %q flags %#x", []any{"/sysroot/nix", uintptr(0x4004)}}, nil, nil), call("bindMount", stub.ExpectArgs{"/host/nix", "/sysroot/nix", uintptr(0x4004), false}, nil, nil),
+			call("stat", stub.ExpectArgs{"/host/root"}, isDirFi(true), nil), call("mkdirAll", stub.ExpectArgs{"/sysroot/root", os.FileMode(0700)}, nil, nil), call("verbosef", stub.ExpectArgs{"mounting %q flags %#x", []any{"/sysroot/root", uintptr(0x4004)}}, nil, nil), call("bindMount", stub.ExpectArgs{"/host/root", "/sysroot/root", uintptr(0x4004), false}, nil, nil),
+			call("stat", stub.ExpectArgs{"/host/run"}, isDirFi(true), nil), call("mkdirAll", stub.ExpectArgs{"/sysroot/run", os.FileMode(0700)}, nil, nil), call("verbosef", stub.ExpectArgs{"mounting %q flags %#x", []any{"/sysroot/run", uintptr(0x4004)}}, nil, nil), call("bindMount", stub.ExpectArgs{"/host/run", "/sysroot/run", uintptr(0x4004), false}, nil, nil),
+			call("stat", stub.ExpectArgs{"/host/srv"}, isDirFi(true), nil), call("mkdirAll", stub.ExpectArgs{"/sysroot/srv", os.FileMode(0700)}, nil, nil), call("verbosef", stub.ExpectArgs{"mounting %q flags %#x", []any{"/sysroot/srv", uintptr(0x4004)}}, nil, nil), call("bindMount", stub.ExpectArgs{"/host/srv", "/sysroot/srv", uintptr(0x4004), false}, nil, nil),
+			call("stat", stub.ExpectArgs{"/host/sys"}, isDirFi(true), nil), call("mkdirAll", stub.ExpectArgs{"/sysroot/sys", os.FileMode(0700)}, nil, nil), call("verbosef", stub.ExpectArgs{"mounting %q flags %#x", []any{"/sysroot/sys", uintptr(0x4004)}}, nil, nil), call("bindMount", stub.ExpectArgs{"/host/sys", "/sysroot/sys", uintptr(0x4004), false}, nil, nil),
+			call("stat", stub.ExpectArgs{"/host/usr"}, isDirFi(true), nil), call("mkdirAll", stub.ExpectArgs{"/sysroot/usr", os.FileMode(0700)}, nil, nil), call("verbosef", stub.ExpectArgs{"mounting %q flags %#x", []any{"/sysroot/usr", uintptr(0x4004)}}, nil, nil), call("bindMount", stub.ExpectArgs{"/host/usr", "/sysroot/usr", uintptr(0x4004), false}, nil, nil),
+			call("stat", stub.ExpectArgs{"/host/var"}, isDirFi(true), nil), call("mkdirAll", stub.ExpectArgs{"/sysroot/var", os.FileMode(0700)}, nil, nil), call("verbosef", stub.ExpectArgs{"mounting %q flags %#x", []any{"/sysroot/var", uintptr(0x4004)}}, nil, nil), call("bindMount", stub.ExpectArgs{"/host/var", "/sysroot/var", uintptr(0x4004), false}, nil, nil),
+		}, nil},
+
+		{"success", &Params{ParentPerm: 0750}, &AutoRootOp{
+			Host: check.MustAbs("/var/lib/planterette/base/debian:f92c9052"),
+		}, []stub.Call{
+			call("readdir", stub.ExpectArgs{"/var/lib/planterette/base/debian:f92c9052"}, stubDir("bin", "dev", "etc", "home", "lib64",
+				"lost+found", "mnt", "nix", "proc", "root", "run", "srv", "sys", "tmp", "usr", "var"), nil),
+			call("evalSymlinks", stub.ExpectArgs{"/var/lib/planterette/base/debian:f92c9052/bin"}, "/var/lib/planterette/base/debian:f92c9052/usr/bin", nil),
+			call("evalSymlinks", stub.ExpectArgs{"/var/lib/planterette/base/debian:f92c9052/home"}, "/var/lib/planterette/base/debian:f92c9052/home", nil),
+			call("evalSymlinks", stub.ExpectArgs{"/var/lib/planterette/base/debian:f92c9052/lib64"}, "/var/lib/planterette/base/debian:f92c9052/lib64", nil),
+			call("evalSymlinks", stub.ExpectArgs{"/var/lib/planterette/base/debian:f92c9052/lost+found"}, "/var/lib/planterette/base/debian:f92c9052/lost+found", nil),
+			call("evalSymlinks", stub.ExpectArgs{"/var/lib/planterette/base/debian:f92c9052/nix"}, "/var/lib/planterette/base/debian:f92c9052/nix", nil),
+			call("evalSymlinks", stub.ExpectArgs{"/var/lib/planterette/base/debian:f92c9052/root"}, "/var/lib/planterette/base/debian:f92c9052/root", nil),
+			call("evalSymlinks", stub.ExpectArgs{"/var/lib/planterette/base/debian:f92c9052/run"}, "/var/lib/planterette/base/debian:f92c9052/run", nil),
+			call("evalSymlinks", stub.ExpectArgs{"/var/lib/planterette/base/debian:f92c9052/srv"}, "/var/lib/planterette/base/debian:f92c9052/srv", nil),
+			call("evalSymlinks", stub.ExpectArgs{"/var/lib/planterette/base/debian:f92c9052/sys"}, "/var/lib/planterette/base/debian:f92c9052/sys", nil),
+			call("evalSymlinks", stub.ExpectArgs{"/var/lib/planterette/base/debian:f92c9052/usr"}, "/var/lib/planterette/base/debian:f92c9052/usr", nil),
+			call("evalSymlinks", stub.ExpectArgs{"/var/lib/planterette/base/debian:f92c9052/var"}, "/var/lib/planterette/base/debian:f92c9052/var", nil),
+		}, nil, []stub.Call{
+			call("stat", stub.ExpectArgs{"/host/var/lib/planterette/base/debian:f92c9052/usr/bin"}, isDirFi(true), nil), call("mkdirAll", stub.ExpectArgs{"/sysroot/bin", os.FileMode(0700)}, nil, nil), call("verbosef", stub.ExpectArgs{"mounting %q on %q flags %#x", []any{"/host/var/lib/planterette/base/debian:f92c9052/usr/bin", "/sysroot/bin", uintptr(0x4005)}}, nil, nil), call("bindMount", stub.ExpectArgs{"/host/var/lib/planterette/base/debian:f92c9052/usr/bin", "/sysroot/bin", uintptr(0x4005), false}, nil, nil),
+			call("stat", stub.ExpectArgs{"/host/var/lib/planterette/base/debian:f92c9052/home"}, isDirFi(true), nil), call("mkdirAll", stub.ExpectArgs{"/sysroot/home", os.FileMode(0700)}, nil, nil), call("verbosef", stub.ExpectArgs{"mounting %q on %q flags %#x", []any{"/host/var/lib/planterette/base/debian:f92c9052/home", "/sysroot/home", uintptr(0x4005)}}, nil, nil), call("bindMount", stub.ExpectArgs{"/host/var/lib/planterette/base/debian:f92c9052/home", "/sysroot/home", uintptr(0x4005), false}, nil, nil),
+			call("stat", stub.ExpectArgs{"/host/var/lib/planterette/base/debian:f92c9052/lib64"}, isDirFi(true), nil), call("mkdirAll", stub.ExpectArgs{"/sysroot/lib64", os.FileMode(0700)}, nil, nil), call("verbosef", stub.ExpectArgs{"mounting %q on %q flags %#x", []any{"/host/var/lib/planterette/base/debian:f92c9052/lib64", "/sysroot/lib64", uintptr(0x4005)}}, nil, nil), call("bindMount", stub.ExpectArgs{"/host/var/lib/planterette/base/debian:f92c9052/lib64", "/sysroot/lib64", uintptr(0x4005), false}, nil, nil),
+			call("stat", stub.ExpectArgs{"/host/var/lib/planterette/base/debian:f92c9052/lost+found"}, isDirFi(true), nil), call("mkdirAll", stub.ExpectArgs{"/sysroot/lost+found", os.FileMode(0700)}, nil, nil), call("verbosef", stub.ExpectArgs{"mounting %q on %q flags %#x", []any{"/host/var/lib/planterette/base/debian:f92c9052/lost+found", "/sysroot/lost+found", uintptr(0x4005)}}, nil, nil), call("bindMount", stub.ExpectArgs{"/host/var/lib/planterette/base/debian:f92c9052/lost+found", "/sysroot/lost+found", uintptr(0x4005), false}, nil, nil),
+			call("stat", stub.ExpectArgs{"/host/var/lib/planterette/base/debian:f92c9052/nix"}, isDirFi(true), nil), call("mkdirAll", stub.ExpectArgs{"/sysroot/nix", os.FileMode(0700)}, nil, nil), call("verbosef", stub.ExpectArgs{"mounting %q on %q flags %#x", []any{"/host/var/lib/planterette/base/debian:f92c9052/nix", "/sysroot/nix", uintptr(0x4005)}}, nil, nil), call("bindMount", stub.ExpectArgs{"/host/var/lib/planterette/base/debian:f92c9052/nix", "/sysroot/nix", uintptr(0x4005), false}, nil, nil),
+			call("stat", stub.ExpectArgs{"/host/var/lib/planterette/base/debian:f92c9052/root"}, isDirFi(true), nil), call("mkdirAll", stub.ExpectArgs{"/sysroot/root", os.FileMode(0700)}, nil, nil), call("verbosef", stub.ExpectArgs{"mounting %q on %q flags %#x", []any{"/host/var/lib/planterette/base/debian:f92c9052/root", "/sysroot/root", uintptr(0x4005)}}, nil, nil), call("bindMount", stub.ExpectArgs{"/host/var/lib/planterette/base/debian:f92c9052/root", "/sysroot/root", uintptr(0x4005), false}, nil, nil),
+			call("stat", stub.ExpectArgs{"/host/var/lib/planterette/base/debian:f92c9052/run"}, isDirFi(true), nil), call("mkdirAll", stub.ExpectArgs{"/sysroot/run", os.FileMode(0700)}, nil, nil), call("verbosef", stub.ExpectArgs{"mounting %q on %q flags %#x", []any{"/host/var/lib/planterette/base/debian:f92c9052/run", "/sysroot/run", uintptr(0x4005)}}, nil, nil), call("bindMount", stub.ExpectArgs{"/host/var/lib/planterette/base/debian:f92c9052/run", "/sysroot/run", uintptr(0x4005), false}, nil, nil),
+			call("stat", stub.ExpectArgs{"/host/var/lib/planterette/base/debian:f92c9052/srv"}, isDirFi(true), nil), call("mkdirAll", stub.ExpectArgs{"/sysroot/srv", os.FileMode(0700)}, nil, nil), call("verbosef", stub.ExpectArgs{"mounting %q on %q flags %#x", []any{"/host/var/lib/planterette/base/debian:f92c9052/srv", "/sysroot/srv", uintptr(0x4005)}}, nil, nil), call("bindMount", stub.ExpectArgs{"/host/var/lib/planterette/base/debian:f92c9052/srv", "/sysroot/srv", uintptr(0x4005), false}, nil, nil),
+			call("stat", stub.ExpectArgs{"/host/var/lib/planterette/base/debian:f92c9052/sys"}, isDirFi(true), nil), call("mkdirAll", stub.ExpectArgs{"/sysroot/sys", os.FileMode(0700)}, nil, nil), call("verbosef", stub.ExpectArgs{"mounting %q on %q flags %#x", []any{"/host/var/lib/planterette/base/debian:f92c9052/sys", "/sysroot/sys", uintptr(0x4005)}}, nil, nil), call("bindMount", stub.ExpectArgs{"/host/var/lib/planterette/base/debian:f92c9052/sys", "/sysroot/sys", uintptr(0x4005), false}, nil, nil),
+			call("stat", stub.ExpectArgs{"/host/var/lib/planterette/base/debian:f92c9052/usr"}, isDirFi(true), nil), call("mkdirAll", stub.ExpectArgs{"/sysroot/usr", os.FileMode(0700)}, nil, nil), call("verbosef", stub.ExpectArgs{"mounting %q on %q flags %#x", []any{"/host/var/lib/planterette/base/debian:f92c9052/usr", "/sysroot/usr", uintptr(0x4005)}}, nil, nil), call("bindMount", stub.ExpectArgs{"/host/var/lib/planterette/base/debian:f92c9052/usr", "/sysroot/usr", uintptr(0x4005), false}, nil, nil),
+			call("stat", stub.ExpectArgs{"/host/var/lib/planterette/base/debian:f92c9052/var"}, isDirFi(true), nil), call("mkdirAll", stub.ExpectArgs{"/sysroot/var", os.FileMode(0700)}, nil, nil), call("verbosef", stub.ExpectArgs{"mounting %q on %q flags %#x", []any{"/host/var/lib/planterette/base/debian:f92c9052/var", "/sysroot/var", uintptr(0x4005)}}, nil, nil), call("bindMount", stub.ExpectArgs{"/host/var/lib/planterette/base/debian:f92c9052/var", "/sysroot/var", uintptr(0x4005), false}, nil, nil),
+		}, nil},
+	})
+
+	checkOpsValid(t, []opValidTestCase{
+		{"nil", (*AutoRootOp)(nil), false},
+		{"zero", new(AutoRootOp), false},
+		{"valid", &AutoRootOp{Host: check.MustAbs("/")}, true},
+	})
+
+	checkOpsBuilder(t, []opsBuilderTestCase{
+		{"pd", new(Ops).Root(check.MustAbs("/"), std.BindWritable), Ops{
+			&AutoRootOp{
+				Host:  check.MustAbs("/"),
+				Flags: std.BindWritable,
+			},
+		}},
+	})
+
+	checkOpIs(t, []opIsTestCase{
+		{"zero", new(AutoRootOp), new(AutoRootOp), false},
+
+		{"internal ne", &AutoRootOp{
+			Host:  check.MustAbs("/"),
+			Flags: std.BindWritable,
+		}, &AutoRootOp{
+			Host:     check.MustAbs("/"),
+			Flags:    std.BindWritable,
+			resolved: []*BindMountOp{new(BindMountOp)},
+		}, true},
+
+		{"flags differs", &AutoRootOp{
+			Host:  check.MustAbs("/"),
+			Flags: std.BindWritable | std.BindDevice,
+		}, &AutoRootOp{
+			Host:  check.MustAbs("/"),
+			Flags: std.BindWritable,
+		}, false},
+
+		{"host differs", &AutoRootOp{
+			Host:  check.MustAbs("/tmp/"),
+			Flags: std.BindWritable,
+		}, &AutoRootOp{
+			Host:  check.MustAbs("/"),
+			Flags: std.BindWritable,
+		}, false},
+
+		{"equals", &AutoRootOp{
+			Host:  check.MustAbs("/"),
+			Flags: std.BindWritable,
+		}, &AutoRootOp{
+			Host:  check.MustAbs("/"),
+			Flags: std.BindWritable,
+		}, true},
+	})
+
+	checkOpMeta(t, []opMetaTestCase{
+		{"root", &AutoRootOp{
+			Host:  check.MustAbs("/"),
+			Flags: std.BindWritable,
+		}, "setting up", `auto root "/" flags 0x2`},
+	})
+}
+
+func TestIsAutoRootBindable(t *testing.T) {
+	t.Parallel()
+
+	testCases := []struct {
+		name string
+		want bool
+		log  bool
+	}{
+		{"proc", false, false},
+		{"dev", false, false},
+		{"tmp", false, false},
+		{"mnt", false, false},
+		{"etc", false, false},
+		{"", false, true},
+
+		{"var", true, false},
+	}
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			t.Parallel()
+			var msg message.Msg
+			if tc.log {
+				msg = &kstub{nil, nil, stub.New(t, func(s *stub.Stub[syscallDispatcher]) syscallDispatcher { panic("unreachable") }, stub.Expect{Calls: []stub.Call{
+					call("verbose", stub.ExpectArgs{[]any{"got unexpected root entry"}}, nil, nil),
+				}})}
+			}
+			if got := IsAutoRootBindable(msg, tc.name); got != tc.want {
+				t.Errorf("IsAutoRootBindable: %v, want %v", got, tc.want)
+			}
+		})
+	}
+}

container/binfmt.go

@@ -0,0 +1,46 @@
+package container
+
+import (
+	"strings"
+	"unsafe"
+
+	"hakurei.app/check"
+)
+
+// escapeBinfmt escapes magic/mask sequences in a [BinfmtEntry].
+func escapeBinfmt(buf *strings.Builder, s string) string {
+	const lowerhex = "0123456789abcdef"
+
+	buf.Reset()
+	for _, c := range unsafe.Slice(unsafe.StringData(s), len(s)) {
+		switch c {
+		case 0, '\\', ':':
+			buf.WriteString(`\x`)
+			buf.WriteByte(lowerhex[c>>4])
+			buf.WriteByte(lowerhex[c&0xf])
+
+		default:
+			buf.WriteByte(c)
+		}
+	}
+	return buf.String()
+}
+
+// BinfmtEntry is an entry to be registered by the init process.
+type BinfmtEntry struct {
+	// The offset of the magic/mask in the file, counted in bytes.
+	Offset byte
+	// The byte sequence binfmt_misc is matching for.
+	Magic string
+	// An (optional, defaults to all 0xff) mask.
+	Mask string
+	// The program that should be invoked with the binary as first argument.
+	Interpreter *check.Absolute
+}
+
+// Valid returns whether e can be registered into the kernel.
+func (e *BinfmtEntry) Valid() bool {
+	return e != nil &&
+		int(e.Offset)+max(len(e.Magic), len(e.Mask)) < 128 &&
+		e.Interpreter != nil && len(e.Interpreter.String()) < 128
+}

container/binfmt_test.go

@@ -0,0 +1,62 @@
+package container
+
+import (
+	"strings"
+	"testing"
+
+	"hakurei.app/fhs"
+)
+
+func TestEscapeBinfmt(t *testing.T) {
+	t.Parallel()
+
+	testCases := []struct {
+		name  string
+		magic string
+		want  string
+	}{
+		{"packed DOS applications", "\x0eDEX", "\x0eDEX"},
+
+		{"riscv64 magic",
+			"\x7fELF\x02\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\xf3\x00",
+			"\x7fELF\x02\x01\x01\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\x02\\x00\xf3\\x00"},
+		{"riscv64 mask",
+			"\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff",
+			"\xff\xff\xff\xff\xff\xff\xff\\x00\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff"},
+	}
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			t.Parallel()
+
+			got := escapeBinfmt(new(strings.Builder), tc.magic)
+			if got != tc.want {
+				t.Errorf("escapeBinfmt: %q, want %q", got, tc.want)
+			}
+		})
+	}
+}
+
+func TestBinfmtEntry(t *testing.T) {
+	t.Parallel()
+
+	testCases := []struct {
+		name  string
+		e     BinfmtEntry
+		valid bool
+	}{
+		{"zero", BinfmtEntry{}, false},
+		{"large offset", BinfmtEntry{Offset: 128}, false},
+		{"long magic", BinfmtEntry{Magic: strings.Repeat("\x00", 128)}, false},
+		{"long mask", BinfmtEntry{Mask: strings.Repeat("\x00", 128)}, false},
+		{"valid", BinfmtEntry{Interpreter: fhs.AbsRoot}, true},
+	}
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			t.Parallel()
+
+			if tc.e.Valid() != tc.valid {
+				t.Errorf("Valid: %v", !tc.valid)
+			}
+		})
+	}
+}

container/capability.go

@@ -3,6 +3,8 @@ package container
 import (
 	"syscall"
 	"unsafe"
+
+	"hakurei.app/ext"
 )
 
 const (
@@ -12,8 +14,11 @@ const (
 	PR_CAP_AMBIENT_RAISE     = 0x2
 	PR_CAP_AMBIENT_CLEAR_ALL = 0x4
 
-	CAP_SYS_ADMIN = 0x15
-	CAP_SETPCAP   = 0x8
+	CAP_SYS_ADMIN    = 0x15
+	CAP_SETPCAP      = 0x8
+	CAP_NET_ADMIN    = 0xc
+	CAP_DAC_OVERRIDE = 0x1
+	CAP_SETFCAP      = 0x1f
 )
 
 type (
@@ -36,10 +41,28 @@ func capToIndex(cap uintptr) uintptr { return cap >> 5 }
 func capToMask(cap uintptr) uint32 { return 1 << uint(cap&31) }
 
 func capset(hdrp *capHeader, datap *[2]capData) error {
-	if _, _, errno := syscall.Syscall(syscall.SYS_CAPSET,
+	r, _, errno := syscall.Syscall(
+		syscall.SYS_CAPSET,
 		uintptr(unsafe.Pointer(hdrp)),
-		uintptr(unsafe.Pointer(&datap[0])), 0); errno != 0 {
+		uintptr(unsafe.Pointer(&datap[0])), 0,
+	)
+	if r != 0 {
 		return errno
 	}
 	return nil
 }
+
+// capBoundingSetDrop drops a capability from the calling thread's capability bounding set.
+func capBoundingSetDrop(cap uintptr) error {
+	return ext.Prctl(syscall.PR_CAPBSET_DROP, cap, 0)
+}
+
+// capAmbientClearAll clears the ambient capability set of the calling thread.
+func capAmbientClearAll() error {
+	return ext.Prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_CLEAR_ALL, 0)
+}
+
+// capAmbientRaise adds to the ambient capability set of the calling thread.
+func capAmbientRaise(cap uintptr) error {
+	return ext.Prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_RAISE, cap)
+}

container/capability_test.go

@@ -0,0 +1,47 @@
+package container
+
+import "testing"
+
+func TestCapToIndex(t *testing.T) {
+	t.Parallel()
+
+	testCases := []struct {
+		name string
+		cap  uintptr
+		want uintptr
+	}{
+		{"CAP_SYS_ADMIN", CAP_SYS_ADMIN, 0},
+		{"CAP_SETPCAP", CAP_SETPCAP, 0},
+		{"CAP_DAC_OVERRIDE", CAP_DAC_OVERRIDE, 0},
+	}
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			t.Parallel()
+			if got := capToIndex(tc.cap); got != tc.want {
+				t.Errorf("capToIndex: %#x, want %#x", got, tc.want)
+			}
+		})
+	}
+}
+
+func TestCapToMask(t *testing.T) {
+	t.Parallel()
+
+	testCases := []struct {
+		name string
+		cap  uintptr
+		want uint32
+	}{
+		{"CAP_SYS_ADMIN", CAP_SYS_ADMIN, 0x200000},
+		{"CAP_SETPCAP", CAP_SETPCAP, 0x100},
+		{"CAP_DAC_OVERRIDE", CAP_DAC_OVERRIDE, 0x2},
+	}
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			t.Parallel()
+			if got := capToMask(tc.cap); got != tc.want {
+				t.Errorf("capToMask: %#x, want %#x", got, tc.want)
+			}
+		})
+	}
+}