internal/kobject: process uevent message

This deals with environment variables generally present in every message.

Signed-off-by: Ophestra <cat@gensokyo.uk>

.gitea/workflows/test.yml

@@ -72,20 +72,20 @@ jobs:
           path: result/*
           retention-days: 1
 
-  hpkg:
-    name: Hpkg
+  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.hpkg
+        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: "hpkg-vm-output"
+          name: "sharefs-vm-output"
           path: result/*
           retention-days: 1
 
@@ -96,7 +96,7 @@ jobs:
       - race
       - sandbox
       - sandbox-race
-      - hpkg
+      - sharefs
     runs-on: nix
     steps:
       - name: Checkout

.github/workflows/README

@@ -1,5 +0,0 @@
-DO NOT ADD NEW ACTIONS HERE
-
-This port is solely for releasing to the github mirror and serves no purpose during development.
-All development happens at https://git.gensokyo.uk/security/hakurei. If you wish to contribute,
-request for an account on git.gensokyo.uk.

.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

@@ -1,35 +1,14 @@
-# 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
+/internal/pkg/testdata/testtool
+/internal/rosa/hakurei_current.tar.gz
 
-# release
-/dist/hakurei-*
-
-# interactive nixos vm
-nixos.qcow2
+# 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>
@@ -8,171 +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 implements the application container of [planterette (WIP)](https://git.gensokyo.uk/security/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 +1,6 @@
+#!/bin/sh -e
+
+TOOLCHAIN_VERSION="$(go version)"
+cd "$(dirname -- "$0")/"
+echo "# Building cmd/dist using ${TOOLCHAIN_VERSION}."
+go run -v --tags=dist ./cmd/dist

check/absolute.go

@@ -0,0 +1,132 @@
+// Package check provides types yielding values checked to meet a condition.
+package check
+
+import (
+	"encoding/json"
+	"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] }
+
+// 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())) }
+
+// GobEncode returns the checked pathname.
+func (a *Absolute) GobEncode() ([]byte, error) {
+	return []byte(a.String()), nil
+}
+
+// GobDecode stores data if it represents an absolute pathname.
+func (a *Absolute) GobDecode(data []byte) error {
+	pathname := string(data)
+	if !filepath.IsAbs(pathname) {
+		return AbsoluteError(pathname)
+	}
+	a.pathname = unique.Make(pathname)
+	return nil
+}
+
+// MarshalJSON returns a JSON representation of the checked pathname.
+func (a *Absolute) MarshalJSON() ([]byte, error) {
+	return json.Marshal(a.String())
+}
+
+// UnmarshalJSON stores data if it represents an absolute pathname.
+func (a *Absolute) UnmarshalJSON(data []byte) error {
+	var pathname string
+	if err := json.Unmarshal(data, &pathname); err != nil {
+		return err
+	}
+	if !filepath.IsAbs(pathname) {
+		return AbsoluteError(pathname)
+	}
+	a.pathname = unique.Make(pathname)
+	return nil
+}
+
+// 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

@@ -11,12 +11,12 @@ import (
 	"testing"
 	_ "unsafe" // for go:linkname
 
-	. "hakurei.app/container/check"
+	. "hakurei.app/check"
 )
 
 // unsafeAbs returns check.Absolute on any string value.
 //
-//go:linkname unsafeAbs hakurei.app/container/check.unsafeAbs
+//go:linkname unsafeAbs hakurei.app/check.unsafeAbs
 func unsafeAbs(pathname string) *Absolute
 
 func TestAbsoluteError(t *testing.T) {
@@ -31,8 +31,8 @@ func TestAbsoluteError(t *testing.T) {
 	}{
 		{"EINVAL", new(AbsoluteError), syscall.EINVAL, true},
 		{"not EINVAL", new(AbsoluteError), syscall.EBADE, false},
-		{"ne val", new(AbsoluteError), &AbsoluteError{Pathname: "etc"}, false},
-		{"equals", &AbsoluteError{Pathname: "etc"}, &AbsoluteError{Pathname: "etc"}, true},
+		{"ne val", new(AbsoluteError), AbsoluteError("etc"), false},
+		{"equals", AbsoluteError("etc"), AbsoluteError("etc"), true},
 	}
 
 	for _, tc := range testCases {
@@ -45,7 +45,7 @@ func TestAbsoluteError(t *testing.T) {
 		t.Parallel()
 
 		want := `path "etc" is not absolute`
-		if got := (&AbsoluteError{Pathname: "etc"}).Error(); got != want {
+		if got := (AbsoluteError("etc")).Error(); got != want {
 			t.Errorf("Error: %q, want %q", got, want)
 		}
 	})
@@ -62,8 +62,8 @@ func TestNewAbs(t *testing.T) {
 		wantErr  error
 	}{
 		{"good", "/etc", MustAbs("/etc"), nil},
-		{"not absolute", "etc", nil, &AbsoluteError{Pathname: "etc"}},
-		{"zero", "", nil, &AbsoluteError{Pathname: ""}},
+		{"not absolute", "etc", nil, AbsoluteError("etc")},
+		{"zero", "", nil, AbsoluteError("")},
 	}
 
 	for _, tc := range testCases {
@@ -84,7 +84,7 @@ func TestNewAbs(t *testing.T) {
 		t.Parallel()
 
 		defer func() {
-			wantPanic := &AbsoluteError{Pathname: "etc"}
+			wantPanic := AbsoluteError("etc")
 
 			if r := recover(); !reflect.DeepEqual(r, wantPanic) {
 				t.Errorf("MustAbs: panic = %v; want %v", r, wantPanic)
@@ -175,7 +175,7 @@ func TestCodecAbsolute(t *testing.T) {
 
 			`"/etc"`, `{"val":"/etc","magic":3236757504}`},
 		{"not absolute", nil,
-			&AbsoluteError{Pathname: "etc"},
+			AbsoluteError("etc"),
 			"\t\x7f\x05\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\x05\x01\x02\xff\x82\x00\x00\x00\x0f\xff\x84\x01\x03etc\x01\xfb\x01\x81\xda\x00\x00\x00",
 

check/overlay.go

@@ -11,7 +11,8 @@ const (
 	SpecialOverlayPath = ":"
 )
 
-// EscapeOverlayDataSegment escapes a string for formatting into the data argument of an overlay mount call.
+// EscapeOverlayDataSegment escapes a string for formatting into the data
+// argument of an overlay mount system call.
 func EscapeOverlayDataSegment(s string) string {
 	if s == "" {
 		return ""

check/overlay_test.go

@@ -3,7 +3,7 @@ package check_test
 import (
 	"testing"
 
-	"hakurei.app/container/check"
+	"hakurei.app/check"
 )
 
 func TestEscapeOverlayDataSegment(t *testing.T) {

cmd/dist/comp/_hakurei

@@ -1,11 +1,11 @@
 #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' \
@@ -57,9 +57,9 @@ __hakurei_instances() {
 {
   local -a _hakurei_cmds
   _hakurei_cmds=(
-    "app:Load and start container from configuration file"
-    "run:Configure and start a permissive container"
-    "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/main.go

@@ -0,0 +1,237 @@
+//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() {
+	fmt.Println()
+	log.SetFlags(0)
+	log.SetPrefix("# ")
+
+	version := getenv("HAKUREI_VERSION", "untagged")
+	prefix := getenv("PREFIX", "/usr")
+	destdir := getenv("DESTDIR", "dist")
+
+	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()
+
+	log.Println("Building hakurei.")
+	mustRun(ctx, "go", "generate", "./...")
+	mustRun(
+		ctx, "go", "build",
+		"-trimpath",
+		"-v", "-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",
+		"./...",
+	)
+	fmt.Println()
+
+	log.Println("Testing Hakurei.")
+	mustRun(
+		ctx, "go", "test",
+		"-ldflags=-buildid= -linkmode external -extldflags=-static",
+		"./...",
+	)
+	fmt.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.NewWriter(io.MultiWriter(f, h))
+	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

@@ -2,6 +2,7 @@ package main
 
 import (
 	"context"
+	"errors"
 	"fmt"
 	"io"
 	"log"
@@ -11,12 +12,11 @@ import (
 	"strconv"
 	"sync"
 	"time"
-	_ "unsafe" // for go:linkname
 
+	"hakurei.app/check"
 	"hakurei.app/command"
-	"hakurei.app/container"
-	"hakurei.app/container/check"
-	"hakurei.app/container/fhs"
+	"hakurei.app/ext"
+	"hakurei.app/fhs"
 	"hakurei.app/hst"
 	"hakurei.app/internal/dbus"
 	"hakurei.app/internal/env"
@@ -27,9 +27,14 @@ import (
 
 // optionalErrorUnwrap calls [errors.Unwrap] and returns the resulting value
 // if it is not nil, or the original value if it is.
-//
-//go:linkname optionalErrorUnwrap hakurei.app/container.optionalErrorUnwrap
-func optionalErrorUnwrap(err error) error
+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 (
@@ -60,9 +65,9 @@ func buildCommand(ctx context.Context, msg message.Msg, early *earlyHardeningErr
 		var (
 			flagIdentifierFile int
 		)
-		c.NewCommand("app", "Load and start container from configuration file", func(args []string) error {
+		c.NewCommand("run", "Load and start container from configuration file", func(args []string) error {
 			if len(args) < 1 {
-				log.Fatal("app requires at least 1 argument")
+				log.Fatal("run requires at least 1 argument")
 			}
 
 			config := tryPath(msg, args[0])
@@ -90,12 +95,15 @@ func buildCommand(ctx context.Context, msg message.Msg, early *earlyHardeningErr
 			flagHomeDir  string
 			flagUserName string
 
+			flagSchedPolicy   string
+			flagSchedPriority int
+
 			flagPrivateRuntime, flagPrivateTmpdir bool
 
 			flagWayland, flagX11, flagDBus, flagPipeWire, flagPulse bool
 		)
 
-		c.NewCommand("run", "Configure and start a permissive container", func(args []string) error {
+		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)
 			}
@@ -132,7 +140,7 @@ func buildCommand(ctx context.Context, msg message.Msg, early *earlyHardeningErr
 					log.Fatal(optionalErrorUnwrap(err))
 					return err
 				} else if progPath, err = check.NewAbs(p); err != nil {
-					log.Fatal(err.Error())
+					log.Fatal(err)
 					return err
 				}
 			}
@@ -151,7 +159,7 @@ func buildCommand(ctx context.Context, msg message.Msg, early *earlyHardeningErr
 				et |= hst.EPipeWire
 			}
 
-			config := &hst.Config{
+			config := hst.Config{
 				ID:          flagID,
 				Identity:    flagIdentity,
 				Groups:      flagGroups,
@@ -178,6 +186,13 @@ func buildCommand(ctx context.Context, msg message.Msg, early *earlyHardeningErr
 				},
 			}
 
+			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{
@@ -187,14 +202,6 @@ func buildCommand(ctx context.Context, msg message.Msg, early *earlyHardeningErr
 				}})
 			}
 
-			// start pipewire-pulse: this most likely exists on host if PipeWire is available
-			if flagPulse {
-				config.Container.Filesystem = append(config.Container.Filesystem, hst.FilesystemConfigJSON{FilesystemConfig: &hst.FSDaemon{
-					Target: fhs.AbsRunUser.Append(strconv.Itoa(container.OverflowUid(msg)), "pulse/native"),
-					Exec:   shell, Args: []string{"-lc", "exec pipewire-pulse"},
-				}})
-			}
-
 			config.Container.Filesystem = append(config.Container.Filesystem,
 				// opportunistically bind kvm
 				hst.FilesystemConfigJSON{FilesystemConfig: &hst.FSBind{
@@ -223,7 +230,7 @@ func buildCommand(ctx context.Context, msg message.Msg, early *earlyHardeningErr
 					homeDir = passwd.HomeDir
 				}
 				if a, err := check.NewAbs(homeDir); err != nil {
-					log.Fatal(err.Error())
+					log.Fatal(err)
 					return err
 				} else {
 					config.Container.Home = a
@@ -243,11 +250,11 @@ func buildCommand(ctx context.Context, msg message.Msg, early *earlyHardeningErr
 					config.SessionBus = dbus.NewConfig(flagID, true, flagDBusMpris)
 				} else {
 					if f, err := os.Open(flagDBusConfigSession); err != nil {
-						log.Fatal(err.Error())
+						log.Fatal(err)
 					} else {
 						decodeJSON(log.Fatal, "load session bus proxy config", f, &config.SessionBus)
 						if err = f.Close(); err != nil {
-							log.Fatal(err.Error())
+							log.Fatal(err)
 						}
 					}
 				}
@@ -255,11 +262,11 @@ func buildCommand(ctx context.Context, msg message.Msg, early *earlyHardeningErr
 				// system bus proxy is optional
 				if flagDBusConfigSystem != "nil" {
 					if f, err := os.Open(flagDBusConfigSystem); err != nil {
-						log.Fatal(err.Error())
+						log.Fatal(err)
 					} else {
 						decodeJSON(log.Fatal, "load system bus proxy config", f, &config.SystemBus)
 						if err = f.Close(); err != nil {
-							log.Fatal(err.Error())
+							log.Fatal(err)
 						}
 					}
 				}
@@ -275,7 +282,7 @@ func buildCommand(ctx context.Context, msg message.Msg, early *earlyHardeningErr
 				}
 			}
 
-			outcome.Main(ctx, msg, config, -1)
+			outcome.Main(ctx, msg, &config, -1)
 			panic("unreachable")
 		}).
 			Flag(&flagDBusConfigSession, "dbus-config", command.StringFlag("builtin"),
@@ -296,6 +303,10 @@ func buildCommand(ctx context.Context, msg message.Msg, early *earlyHardeningErr
 				"Container home directory").
 			Flag(&flagUserName, "u", command.StringFlag("chronos"),
 				"Passwd user name within sandbox").
+			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),
@@ -317,7 +328,7 @@ func buildCommand(ctx context.Context, msg message.Msg, early *earlyHardeningErr
 			flagShort   bool
 			flagNoStore bool
 		)
-		c.NewCommand("show", "Show live or local app configuration", func(args []string) error {
+		c.NewCommand("show", "Show live or local instance configuration", func(args []string) error {
 			switch len(args) {
 			case 0: // system
 				printShowSystem(os.Stdout, flagShort, flagJSON)

cmd/hakurei/command_test.go

@@ -23,9 +23,9 @@ func TestHelp(t *testing.T) {
 Usage:	hakurei [-h | --help] [-v] [--json] COMMAND [OPTIONS]
 
 Commands:
-    app         Load and start container from configuration file
-    run         Configure and start a permissive container
-    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
@@ -35,8 +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>] [--private-runtime] [--private-tmpdir] [--wayland] [-X] [--dbus] [--pipewire] [--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
@@ -60,6 +60,10 @@ Flags:
     	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

cmd/hakurei/json_test.go

@@ -5,7 +5,7 @@ import (
 	"strings"
 	"testing"
 
-	"hakurei.app/container/stub"
+	"hakurei.app/internal/stub"
 )
 
 func TestDecodeJSON(t *testing.T) {

cmd/hakurei/main.go

@@ -1,8 +1,42 @@
+// 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"
@@ -13,15 +47,13 @@ import (
 	"syscall"
 
 	"hakurei.app/container"
+	"hakurei.app/ext"
 	"hakurei.app/message"
 )
 
-var (
-	errSuccess = errors.New("success")
-
-	//go:embed LICENSE
-	license string
-)
+//go:generate cp ../../LICENSE .
+//go:embed LICENSE
+var license string
 
 // earlyHardeningErrs are errors collected while setting up early hardening feature.
 type earlyHardeningErrs struct{ yamaLSM, dumpable error }
@@ -30,13 +62,13 @@ func main() {
 	// early init path, skips root check and duplicate PR_SET_DUMPABLE
 	container.TryArgv0(nil)
 
-	log.SetPrefix("hakurei: ")
 	log.SetFlags(0)
+	log.SetPrefix("hakurei: ")
 	msg := message.New(log.Default())
 
 	early := earlyHardeningErrs{
-		yamaLSM:  container.SetPtracer(0),
-		dumpable: container.SetDumpable(container.SUID_DUMP_DISABLE),
+		yamaLSM:  ext.SetPtracer(0),
+		dumpable: ext.SetDumpable(ext.SUID_DUMP_DISABLE),
 	}
 
 	if os.Geteuid() == 0 {

cmd/hakurei/parse.go

@@ -17,8 +17,9 @@ import (
 )
 
 // 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].
+//
+// 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)
@@ -46,7 +47,8 @@ func tryPath(msg message.Msg, name string) (config *hst.Config) {
 	return
 }
 
-// tryFd returns a [io.ReadCloser] if name represents an integer corresponding to a valid file descriptor.
+// 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) {
@@ -60,7 +62,12 @@ func tryFd(msg message.Msg, name string) io.ReadCloser {
 
 		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 _, _, errno := syscall.Syscall(
+			syscall.SYS_FCNTL,
+			fd,
+			syscall.F_GETFD,
+			0,
+		); errno != 0 {
 			if errors.Is(errno, syscall.EBADF) { // reject bad fd
 				return nil
 			}
@@ -75,10 +82,12 @@ func tryFd(msg message.Msg, name string) io.ReadCloser {
 	}
 }
 
-// shortLengthMin is the minimum length a short form identifier can have and still be interpreted as an identifier.
+// 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.
+// shortIdentifier returns an eight character short representation of [hst.ID]
+// from its random bytes.
 func shortIdentifier(id *hst.ID) string {
 	return shortIdentifierString(id.String())
 }
@@ -88,7 +97,8 @@ 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.
+// 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
@@ -96,7 +106,8 @@ func tryIdentifier(msg message.Msg, name string, s *store.Store) *hst.State {
 	)
 
 	var likely uintptr
-	if len(name) >= shortLengthMin && len(name) <= len(hst.ID{}) { // half the hex representation
+	// 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' {

cmd/hakurei/parse_test.go

@@ -6,7 +6,7 @@ import (
 	"testing"
 	"time"
 
-	"hakurei.app/container/check"
+	"hakurei.app/check"
 	"hakurei.app/hst"
 	"hakurei.app/internal/store"
 	"hakurei.app/message"

cmd/hakurei/print_test.go

@@ -7,7 +7,7 @@ import (
 	"testing"
 	"time"
 
-	"hakurei.app/container/check"
+	"hakurei.app/check"
 	"hakurei.app/hst"
 	"hakurei.app/internal/store"
 	"hakurei.app/message"

cmd/hpkg/README

@@ -1,7 +0,0 @@
-This program is a proof of concept and is now deprecated. It is only kept
-around for API demonstration purposes and to make the most out of the test
-suite.
-
-This program is replaced by planterette, which can be found at
-https://git.gensokyo.uk/security/planterette. Development effort should be
-focused there instead.

cmd/hpkg/app.go

@@ -1,173 +0,0 @@
-package main
-
-import (
-	"encoding/json"
-	"log"
-	"os"
-
-	"hakurei.app/container/check"
-	"hakurei.app/container/fhs"
-	"hakurei.app/hst"
-)
-
-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]
-	HostNet bool `json:"net,omitempty"`
-	// passed through to [hst.Config]
-	HostAbstract bool `json:"abstract,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 *hst.BusConfig `json:"system_bus,omitempty"`
-	// passed through to [hst.Config]
-	SessionBus *hst.BusConfig `json:"session_bus,omitempty"`
-	// passed through to [hst.Config]
-	Enablements *hst.Enablements `json:"enablements,omitempty"`
-
-	// 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 *check.Absolute `json:"launcher"`
-	// store path to /run/current-system
-	CurrentSystem *check.Absolute `json:"current_system"`
-	// store path to home-manager activation package
-	ActivationPackage string `json:"activation_package"`
-}
-
-func (app *appInfo) toHst(pathSet *appPathSet, pathname *check.Absolute, argv []string, flagDropShell bool) *hst.Config {
-	config := &hst.Config{
-		ID: app.ID,
-
-		Enablements: app.Enablements,
-
-		SystemBus:     app.SystemBus,
-		SessionBus:    app.SessionBus,
-		DirectWayland: app.DirectWayland,
-
-		Identity: app.Identity,
-		Groups:   app.Groups,
-
-		Container: &hst.ContainerConfig{
-			Hostname: formatHostname(app.Name),
-			Filesystem: []hst.FilesystemConfigJSON{
-				{FilesystemConfig: &hst.FSBind{Target: fhs.AbsEtc, Source: pathSet.cacheDir.Append("etc"), Special: true}},
-				{FilesystemConfig: &hst.FSBind{Source: pathSet.nixPath.Append("store"), Target: pathNixStore}},
-				{FilesystemConfig: &hst.FSLink{Target: pathCurrentSystem, Linkname: app.CurrentSystem.String()}},
-				{FilesystemConfig: &hst.FSLink{Target: pathBin, Linkname: pathSwBin.String()}},
-				{FilesystemConfig: &hst.FSLink{Target: fhs.AbsUsrBin, Linkname: pathSwBin.String()}},
-				{FilesystemConfig: &hst.FSBind{Source: pathSet.metaPath, Target: hst.AbsPrivateTmp.Append("app")}},
-				{FilesystemConfig: &hst.FSBind{Source: fhs.AbsEtc.Append("resolv.conf"), Optional: true}},
-				{FilesystemConfig: &hst.FSBind{Source: fhs.AbsSys.Append("block"), Optional: true}},
-				{FilesystemConfig: &hst.FSBind{Source: fhs.AbsSys.Append("bus"), Optional: true}},
-				{FilesystemConfig: &hst.FSBind{Source: fhs.AbsSys.Append("class"), Optional: true}},
-				{FilesystemConfig: &hst.FSBind{Source: fhs.AbsSys.Append("dev"), Optional: true}},
-				{FilesystemConfig: &hst.FSBind{Source: fhs.AbsSys.Append("devices"), Optional: true}},
-				{FilesystemConfig: &hst.FSBind{Target: pathDataData.Append(app.ID), Source: pathSet.homeDir, Write: true, Ensure: true}},
-			},
-
-			Username: "hakurei",
-			Shell:    pathShell,
-			Home:     pathDataData.Append(app.ID),
-
-			Path: pathname,
-			Args: argv,
-		},
-		ExtraPerms: []hst.ExtraPermConfig{
-			{Path: dataHome, Execute: true},
-			{Ensure: true, Path: pathSet.baseDir, Read: true, Write: true, Execute: true},
-		},
-	}
-
-	if app.Devel {
-		config.Container.Flags |= hst.FDevel
-	}
-	if app.Userns {
-		config.Container.Flags |= hst.FUserns
-	}
-	if app.HostNet {
-		config.Container.Flags |= hst.FHostNet
-	}
-	if app.HostAbstract {
-		config.Container.Flags |= hst.FHostAbstract
-	}
-	if app.Device {
-		config.Container.Flags |= hst.FDevice
-	}
-	if app.Tty || flagDropShell {
-		config.Container.Flags |= hst.FTty
-	}
-	if app.MapRealUID {
-		config.Container.Flags |= hst.FMapRealUID
-	}
-	if app.Multiarch {
-		config.Container.Flags |= hst.FMultiarch
-	}
-	config.Container.Flags |= hst.FShareRuntime | hst.FShareTmpdir
-	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")
-	}
-	if bundle.Launcher == nil {
-		beforeFail()
-		log.Fatal("launcher must not be empty")
-	}
-	if bundle.CurrentSystem == nil {
-		beforeFail()
-		log.Fatal("current-system 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/hpkg/build.nix

@@ -1,256 +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_audio ? 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.${system};
-        enable32bits = isIntelX86Platform;
-        enableIntelX86Extensions = isIntelX86Platform;
-      };
-    in
-    symlinkJoin {
-      name = "nixGL-mesa";
-      paths = with nixGLPackages; [
-        nixGLIntel
-        nixVulkanIntel
-      ];
-    };
-
-  info = builtins.toJSON {
-    inherit
-      name
-      version
-      id
-      identity
-      launcher
-      groups
-      userns
-      net
-      dev
-      no_new_session
-      map_real_uid
-      direct_wayland
-      system_bus
-      gpu
-      ;
-
-    session_bus =
-      if session_bus != null then
-        (session_bus (extendSessionDefault id))
-      else
-        (extendSessionDefault id {
-          talk = [ ];
-          own = [ ];
-          call = { };
-          broadcast = { };
-        });
-
-    enablements = {
-      wayland = allow_wayland;
-      x11 = allow_x11;
-      dbus = allow_dbus;
-      pipewire = allow_audio;
-    };
-
-    mesa = if gpu then mesaWrappers else null;
-    nix_gl = if gpu then nixGL else null;
-    current_system = nixos.config.system.build.toplevel;
-    activation_package = homeManagerConfiguration.activationPackage;
-  };
-in
-
-stdenv.mkDerivation {
-  name = "${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/hpkg/main.go

@@ -1,335 +0,0 @@
-package main
-
-import (
-	"context"
-	"encoding/json"
-	"errors"
-	"log"
-	"os"
-	"os/signal"
-	"path"
-	"syscall"
-
-	"hakurei.app/command"
-	"hakurei.app/container/check"
-	"hakurei.app/container/fhs"
-	"hakurei.app/hst"
-	"hakurei.app/message"
-)
-
-var (
-	errSuccess = errors.New("success")
-)
-
-func main() {
-	log.SetPrefix("hpkg: ")
-	log.SetFlags(0)
-	msg := message.New(log.Default())
-
-	if err := os.Setenv("SHELL", pathShell.String()); err != nil {
-		log.Fatalf("cannot set $SHELL: %v", err)
-	}
-
-	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, "hpkg", func([]string) error { msg.SwapVerbose(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 hpkg.
-				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 *check.Absolute
-			if p, err := os.MkdirTemp("", "hpkg.*"); err != nil {
-				log.Printf("cannot create temporary directory: %v", err)
-				return err
-			} else if workDir, err = check.NewAbs(p); err != nil {
-				log.Printf("invalid temporary directory: %v", err)
-				return err
-			}
-			cleanup := func() {
-				// should be faster than a native implementation
-				mustRun(msg, chmod, "-R", "+w", workDir.String())
-				mustRun(msg, rm, "-rf", workDir.String())
-			}
-			beforeRunFail.Store(&cleanup)
-
-			mustRun(msg, tar, "-C", workDir.String(), "-xf", pkgPath)
-
-			/*
-				Parse bundle and app metadata, do pre-install checks.
-			*/
-
-			bundle := loadAppInfo(path.Join(workDir.String(), "bundle.json"), cleanup)
-			pathSet := pathSetByApp(bundle.ID)
-
-			a := bundle
-			if s, err := os.Stat(pathSet.metaPath.String()); 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.String(), 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
-				msg.Verbosef("installing application %q version %q over local %q",
-					bundle.ID, bundle.Version, a.Version)
-			} else {
-				msg.Verbosef("application %q clean installation", bundle.ID)
-				// sec: should install credentials
-			}
-
-			/*
-				Setup steps for files owned by the target user.
-			*/
-
-			withCacheDir(ctx, msg, "install", []string{
-				// export inner bundle path in the environment
-				"export BUNDLE=" + hst.PrivateTmp + "/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, msg, "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, msg, "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.String()+"~", 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.String()+"~", pathSet.metaPath.String()); 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.String(), 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, msg, "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.FilesystemConfigJSON{
-						{FilesystemConfig: &hst.FSBind{Source: fhs.AbsEtc.Append("resolv.conf"), Optional: true}},
-						{FilesystemConfig: &hst.FSBind{Source: fhs.AbsSys.Append("block"), Optional: true}},
-						{FilesystemConfig: &hst.FSBind{Source: fhs.AbsSys.Append("bus"), Optional: true}},
-						{FilesystemConfig: &hst.FSBind{Source: fhs.AbsSys.Append("class"), Optional: true}},
-						{FilesystemConfig: &hst.FSBind{Source: fhs.AbsSys.Append("dev"), Optional: true}},
-						{FilesystemConfig: &hst.FSBind{Source: fhs.AbsSys.Append("devices"), Optional: true}},
-					}...)
-					appendGPUFilesystem(config)
-					return config
-				}, a, pathSet, flagDropShellNixGL, func() {})
-			}
-
-			/*
-				Create app configuration.
-			*/
-
-			pathname := a.Launcher
-			argv := make([]string, 1, len(args))
-			if flagDropShell {
-				pathname = pathShell
-				argv[0] = bash
-			} else {
-				argv[0] = a.Launcher.String()
-			}
-			argv = append(argv, args[1:]...)
-			config := a.toHst(pathSet, pathname, argv, flagDropShell)
-
-			/*
-				Expose GPU devices.
-			*/
-
-			if a.GPU {
-				config.Container.Filesystem = append(config.Container.Filesystem,
-					hst.FilesystemConfigJSON{FilesystemConfig: &hst.FSBind{Source: pathSet.nixPath.Append(".nixGL"), Target: hst.AbsPrivateTmp.Append("nixGL")}})
-				appendGPUFilesystem(config)
-			}
-
-			/*
-				Spawn app.
-			*/
-
-			mustRunApp(ctx, msg, 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) {
-		msg.Verbosef("command returned %v", err)
-		if errors.Is(err, errSuccess) {
-			msg.BeforeExit()
-			os.Exit(0)
-		}
-	})
-	log.Fatal("unreachable")
-}

cmd/hpkg/paths.go

@@ -1,117 +0,0 @@
-package main
-
-import (
-	"log"
-	"os"
-	"os/exec"
-	"strconv"
-	"sync/atomic"
-
-	"hakurei.app/container/check"
-	"hakurei.app/container/fhs"
-	"hakurei.app/hst"
-	"hakurei.app/message"
-)
-
-const bash = "bash"
-
-var (
-	dataHome *check.Absolute
-)
-
-func init() {
-	// dataHome
-	if a, err := check.NewAbs(os.Getenv("HAKUREI_DATA_HOME")); err == nil {
-		dataHome = a
-	} else {
-		dataHome = fhs.AbsVarLib.Append("hakurei/" + strconv.Itoa(os.Getuid()))
-	}
-}
-
-var (
-	pathBin = fhs.AbsRoot.Append("bin")
-
-	pathNix           = check.MustAbs("/nix/")
-	pathNixStore      = pathNix.Append("store/")
-	pathCurrentSystem = fhs.AbsRun.Append("current-system")
-	pathSwBin         = pathCurrentSystem.Append("sw/bin/")
-	pathShell         = pathSwBin.Append(bash)
-
-	pathData     = check.MustAbs("/data")
-	pathDataData = pathData.Append("data")
-)
-
-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(msg message.Msg, name string, arg ...string) {
-	msg.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 *check.Absolute
-	// ${baseDir}/app
-	metaPath *check.Absolute
-	// ${baseDir}/files
-	homeDir *check.Absolute
-	// ${baseDir}/cache
-	cacheDir *check.Absolute
-	// ${baseDir}/cache/nix
-	nixPath *check.Absolute
-}
-
-func pathSetByApp(id string) *appPathSet {
-	pathSet := new(appPathSet)
-	pathSet.baseDir = dataHome.Append(id)
-	pathSet.metaPath = pathSet.baseDir.Append("app")
-	pathSet.homeDir = pathSet.baseDir.Append("files")
-	pathSet.cacheDir = pathSet.baseDir.Append("cache")
-	pathSet.nixPath = pathSet.cacheDir.Append("nix")
-	return pathSet
-}
-
-func appendGPUFilesystem(config *hst.Config) {
-	config.Container.Filesystem = append(config.Container.Filesystem, []hst.FilesystemConfigJSON{
-		// flatpak commit 763a686d874dd668f0236f911de00b80766ffe79
-		{FilesystemConfig: &hst.FSBind{Source: fhs.AbsDev.Append("dri"), Device: true, Optional: true}},
-		// mali
-		{FilesystemConfig: &hst.FSBind{Source: fhs.AbsDev.Append("mali"), Device: true, Optional: true}},
-		{FilesystemConfig: &hst.FSBind{Source: fhs.AbsDev.Append("mali0"), Device: true, Optional: true}},
-		{FilesystemConfig: &hst.FSBind{Source: fhs.AbsDev.Append("umplock"), Device: true, Optional: true}},
-		// nvidia
-		{FilesystemConfig: &hst.FSBind{Source: fhs.AbsDev.Append("nvidiactl"), Device: true, Optional: true}},
-		{FilesystemConfig: &hst.FSBind{Source: fhs.AbsDev.Append("nvidia-modeset"), Device: true, Optional: true}},
-		// nvidia OpenCL/CUDA
-		{FilesystemConfig: &hst.FSBind{Source: fhs.AbsDev.Append("nvidia-uvm"), Device: true, Optional: true}},
-		{FilesystemConfig: &hst.FSBind{Source: fhs.AbsDev.Append("nvidia-uvm-tools"), Device: true, Optional: true}},
-
-		// flatpak commit d2dff2875bb3b7e2cd92d8204088d743fd07f3ff
-		{FilesystemConfig: &hst.FSBind{Source: fhs.AbsDev.Append("nvidia0"), Device: true, Optional: true}}, {FilesystemConfig: &hst.FSBind{Source: fhs.AbsDev.Append("nvidia1"), Device: true, Optional: true}},
-		{FilesystemConfig: &hst.FSBind{Source: fhs.AbsDev.Append("nvidia2"), Device: true, Optional: true}}, {FilesystemConfig: &hst.FSBind{Source: fhs.AbsDev.Append("nvidia3"), Device: true, Optional: true}},
-		{FilesystemConfig: &hst.FSBind{Source: fhs.AbsDev.Append("nvidia4"), Device: true, Optional: true}}, {FilesystemConfig: &hst.FSBind{Source: fhs.AbsDev.Append("nvidia5"), Device: true, Optional: true}},
-		{FilesystemConfig: &hst.FSBind{Source: fhs.AbsDev.Append("nvidia6"), Device: true, Optional: true}}, {FilesystemConfig: &hst.FSBind{Source: fhs.AbsDev.Append("nvidia7"), Device: true, Optional: true}},
-		{FilesystemConfig: &hst.FSBind{Source: fhs.AbsDev.Append("nvidia8"), Device: true, Optional: true}}, {FilesystemConfig: &hst.FSBind{Source: fhs.AbsDev.Append("nvidia9"), Device: true, Optional: true}},
-		{FilesystemConfig: &hst.FSBind{Source: fhs.AbsDev.Append("nvidia10"), Device: true, Optional: true}}, {FilesystemConfig: &hst.FSBind{Source: fhs.AbsDev.Append("nvidia11"), Device: true, Optional: true}},
-		{FilesystemConfig: &hst.FSBind{Source: fhs.AbsDev.Append("nvidia12"), Device: true, Optional: true}}, {FilesystemConfig: &hst.FSBind{Source: fhs.AbsDev.Append("nvidia13"), Device: true, Optional: true}},
-		{FilesystemConfig: &hst.FSBind{Source: fhs.AbsDev.Append("nvidia14"), Device: true, Optional: true}}, {FilesystemConfig: &hst.FSBind{Source: fhs.AbsDev.Append("nvidia15"), Device: true, Optional: true}},
-		{FilesystemConfig: &hst.FSBind{Source: fhs.AbsDev.Append("nvidia16"), Device: true, Optional: true}}, {FilesystemConfig: &hst.FSBind{Source: fhs.AbsDev.Append("nvidia17"), Device: true, Optional: true}},
-		{FilesystemConfig: &hst.FSBind{Source: fhs.AbsDev.Append("nvidia18"), Device: true, Optional: true}}, {FilesystemConfig: &hst.FSBind{Source: fhs.AbsDev.Append("nvidia19"), Device: true, Optional: true}},
-	}...)
-}

cmd/hpkg/proc.go

@@ -1,61 +0,0 @@
-package main
-
-import (
-	"context"
-	"encoding/json"
-	"errors"
-	"io"
-	"log"
-	"os"
-	"os/exec"
-
-	"hakurei.app/hst"
-	"hakurei.app/internal/info"
-	"hakurei.app/message"
-)
-
-var hakureiPathVal = info.MustHakureiPath().String()
-
-func mustRunApp(ctx context.Context, msg message.Msg, 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 msg.IsVerbose() {
-			cmd = exec.CommandContext(ctx, hakureiPathVal, "-v", "app", "3")
-		} else {
-			cmd = exec.CommandContext(ctx, hakureiPathVal, "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()
-			msg.BeforeExit()
-			os.Exit(exitError.ExitCode())
-		} else {
-			beforeFail()
-			log.Fatalf("cannot wait: %v", err)
-		}
-	}
-}

cmd/hpkg/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/hpkg/test/default.nix

@@ -1,34 +0,0 @@
-{
-  nixosTest,
-  callPackage,
-
-  system,
-  self,
-}:
-let
-  buildPackage = self.buildPackage.${system};
-in
-nixosTest {
-  name = "hpkg";
-  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/hpkg/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/hpkg/test/test.py

@@ -1,110 +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 = instances[0]
-
-    if len(instance['container']['args']) != 1 or not (instance['container']['args'][0].startswith("/nix/store/")) or f"hakurei-{name}-" not in (instance['container']['args'][0]):
-        raise Exception(f"unexpected args {instance['container']['args']}")
-
-    if instance['enablements'] != enablements:
-        raise Exception(f"unexpected enablements {instance['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 hpkg directory:
-machine.succeed("install -dm 0700 -o alice -g users /var/lib/hakurei/1000")
-
-# Install hpkg app:
-swaymsg("exec hpkg -v install /etc/foot.pkg && touch /tmp/hpkg-install-ok")
-machine.wait_for_file("/tmp/hpkg-install-ok")
-
-# Start app (foot) with Wayland enablement:
-swaymsg("exec hpkg -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.0/tmpdir/2/success-client")
-collect_state_ui("app_wayland")
-check_state("foot", {"wayland": True, "dbus": True, "pipewire": True})
-# Verify acl on XDG_RUNTIME_DIR:
-print(machine.succeed("getfacl --absolute-names --omit-header --numeric /tmp/hakurei.0/runtime | grep 10002"))
-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 /tmp/hakurei.0/runtime | grep 10002")
-
-# Exit Sway and verify process exit status 0:
-swaymsg("exit", succeed=False)
-machine.wait_for_file("/tmp/sway-exit-ok")
-
-# Print hakurei share and rundir contents:
-print(machine.succeed("find /tmp/hakurei.0 "
-    + "-path '/tmp/hakurei.0/runtime/*/*' -prune -o "
-    + "-path '/tmp/hakurei.0/tmpdir/*/*' -prune -o "
-    + "-print"))
-print(machine.fail("ls /run/user/1000/hakurei"))

cmd/hpkg/with.go

@@ -1,130 +0,0 @@
-package main
-
-import (
-	"context"
-	"os"
-	"strings"
-
-	"hakurei.app/container/check"
-	"hakurei.app/container/fhs"
-	"hakurei.app/hst"
-	"hakurei.app/message"
-)
-
-func withNixDaemon(
-	ctx context.Context,
-	msg message.Msg,
-	action string, command []string, net bool, updateConfig func(config *hst.Config) *hst.Config,
-	app *appInfo, pathSet *appPathSet, dropShell bool, beforeFail func(),
-) {
-	flags := hst.FMultiarch | hst.FUserns // nix sandbox requires userns
-	if net {
-		flags |= hst.FHostNet
-	}
-	if dropShell {
-		flags |= hst.FTty
-	}
-
-	mustRunAppDropShell(ctx, msg, updateConfig(&hst.Config{
-		ID: 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,
-
-			Filesystem: []hst.FilesystemConfigJSON{
-				{FilesystemConfig: &hst.FSBind{Target: fhs.AbsEtc, Source: pathSet.cacheDir.Append("etc"), Special: true}},
-				{FilesystemConfig: &hst.FSBind{Source: pathSet.nixPath, Target: pathNix, Write: true}},
-				{FilesystemConfig: &hst.FSLink{Target: pathCurrentSystem, Linkname: app.CurrentSystem.String()}},
-				{FilesystemConfig: &hst.FSLink{Target: pathBin, Linkname: pathSwBin.String()}},
-				{FilesystemConfig: &hst.FSLink{Target: fhs.AbsUsrBin, Linkname: pathSwBin.String()}},
-				{FilesystemConfig: &hst.FSBind{Target: pathDataData.Append(app.ID), Source: pathSet.homeDir, Write: true, Ensure: true}},
-			},
-
-			Username: "hakurei",
-			Shell:    pathShell,
-			Home:     pathDataData.Append(app.ID),
-
-			Path: pathShell,
-			Args: []string{bash, "-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",
-			},
-
-			Flags: flags,
-		},
-	}), dropShell, beforeFail)
-}
-
-func withCacheDir(
-	ctx context.Context,
-	msg message.Msg,
-	action string, command []string, workDir *check.Absolute,
-	app *appInfo, pathSet *appPathSet, dropShell bool, beforeFail func(),
-) {
-	flags := hst.FMultiarch
-	if dropShell {
-		flags |= hst.FTty
-	}
-
-	mustRunAppDropShell(ctx, msg, &hst.Config{
-		ID: app.ID,
-
-		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,
-
-			Filesystem: []hst.FilesystemConfigJSON{
-				{FilesystemConfig: &hst.FSBind{Target: fhs.AbsEtc, Source: workDir.Append(fhs.Etc), Special: true}},
-				{FilesystemConfig: &hst.FSBind{Source: workDir.Append("nix"), Target: pathNix}},
-				{FilesystemConfig: &hst.FSLink{Target: pathCurrentSystem, Linkname: app.CurrentSystem.String()}},
-				{FilesystemConfig: &hst.FSLink{Target: pathBin, Linkname: pathSwBin.String()}},
-				{FilesystemConfig: &hst.FSLink{Target: fhs.AbsUsrBin, Linkname: pathSwBin.String()}},
-				{FilesystemConfig: &hst.FSBind{Source: workDir, Target: hst.AbsPrivateTmp.Append("bundle")}},
-				{FilesystemConfig: &hst.FSBind{Target: pathDataData.Append(app.ID, "cache"), Source: pathSet.cacheDir, Write: true, Ensure: true}},
-			},
-
-			Username: "nixos",
-			Shell:    pathShell,
-			Home:     pathDataData.Append(app.ID, "cache"),
-
-			Path: pathShell,
-			Args: []string{bash, "-lc", strings.Join(command, " && ")},
-
-			Flags: flags,
-		},
-	}, dropShell, beforeFail)
-}
-
-func mustRunAppDropShell(ctx context.Context, msg message.Msg, config *hst.Config, dropShell bool, beforeFail func()) {
-	if dropShell {
-		if config.Container != nil {
-			config.Container.Args = []string{bash, "-l"}
-		}
-		mustRunApp(ctx, msg, config, beforeFail)
-		beforeFail()
-		msg.BeforeExit()
-		os.Exit(0)
-	}
-	mustRunApp(ctx, msg, config, beforeFail)
-}

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

@@ -1,6 +1,6 @@
 package main
 
-/* copied from hst and must never be changed */
+/* keep in sync with hst */
 
 const (
 	userOffset = 100000

cmd/hsu/main.go

@@ -1,13 +1,64 @@
+// 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
 
-// minimise imports to avoid inadvertently calling init or global variable functions
-
 import (
 	"bytes"
 	"fmt"
 	"log"
 	"os"
-	"path"
+	"path/filepath"
 	"runtime"
 	"slices"
 	"strconv"
@@ -16,10 +67,13 @@ import (
 )
 
 const (
-	// envIdentity is the name of the environment variable holding a
-	// single byte representing the shim setup pipe file descriptor.
+	// envShim is the name of the environment variable holding a single byte
+	// representing the shim setup pipe file descriptor.
 	envShim = "HAKUREI_SHIM"
-	// envGroups holds a ' ' separated list of string representations of
+	// 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"
 )
@@ -35,7 +89,6 @@ func main() {
 
 	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")
@@ -49,13 +102,13 @@ func main() {
 		log.Fatal("this program must not be started by root")
 	}
 
-	if !path.IsAbs(hakureiPath) {
+	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)") {
@@ -99,8 +152,6 @@ func main() {
 		// last possible uid outcome
 		uidEnd = 999919999
 	)
-
-	// cast to int for use with library functions
 	uid := int(toUser(userid, identity))
 
 	// final bounds check to catch any bugs
@@ -136,7 +187,6 @@ func main() {
 	}
 
 	// 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)
 	}
@@ -146,10 +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/parse.go

@@ -18,8 +18,9 @@ const (
 	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.
+// 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 {
@@ -40,12 +41,14 @@ func parseUint32Fast(s string) (uint32, error) {
 	return n, nil
 }
 
-// parseConfig reads a list of allowed users from r until it encounters puid or [io.EOF].
+// 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.
+// 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) {
@@ -81,10 +84,6 @@ func parseConfig(r io.Reader, puid uint32) (userid uint32, ok bool, err error) {
 	return useridEnd + 1, false, s.Err()
 }
 
-// hsuConfPath is an absolute pathname to the hsu configuration file.
-// Its contents are interpreted by parseConfig.
-const hsuConfPath = "/etc/hsurc"
-
 // 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.
@@ -112,10 +111,6 @@ func mustParseConfig(puid int) (userid uint32) {
 	return
 }
 
-// envIdentity is the name of the environment variable holding a
-// string representation of the current application identity.
-var envIdentity = "HAKUREI_IDENTITY"
-
 // 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 {

cmd/mbf/main.go

@@ -0,0 +1,707 @@
+// 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"
+	"errors"
+	"fmt"
+	"io"
+	"log"
+	"os"
+	"os/signal"
+	"path/filepath"
+	"runtime"
+	"strconv"
+	"strings"
+	"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"
+)
+
+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")
+	}
+
+	var cache *pkg.Cache
+	ctx, stop := signal.NotifyContext(context.Background(),
+		syscall.SIGINT, syscall.SIGTERM, syscall.SIGHUP)
+	defer stop()
+	defer func() {
+		if cache != nil {
+			cache.Close()
+		}
+
+		if r := recover(); r != nil {
+			fmt.Println(r)
+			log.Fatal("consider scrubbing the on-disk cache")
+		}
+	}()
+
+	var (
+		flagQuiet bool
+		flagCures int
+		flagBase  string
+		flagIdle  bool
+
+		flagHostAbstract bool
+	)
+	c := command.New(os.Stderr, log.Printf, "mbf", func([]string) (err error) {
+		msg.SwapVerbose(!flagQuiet)
+
+		flagBase = os.ExpandEnv(flagBase)
+		if flagBase == "" {
+			flagBase = "cache"
+		}
+
+		var base *check.Absolute
+		if flagBase, err = filepath.Abs(flagBase); err != nil {
+			return
+		} else if base, err = check.NewAbs(flagBase); err != nil {
+			return
+		}
+
+		var flags int
+		if flagIdle {
+			flags |= pkg.CSchedIdle
+		}
+		if flagHostAbstract {
+			flags |= pkg.CHostAbstract
+		}
+		cache, err = pkg.Open(ctx, msg, flags, flagCures, base)
+
+		return
+	}).Flag(
+		&flagQuiet,
+		"q", command.BoolFlag(false),
+		"Do not print cure messages",
+	).Flag(
+		&flagCures,
+		"cures", command.IntFlag(0),
+		"Maximum number of dependencies to cure at any given time",
+	).Flag(
+		&flagBase,
+		"d", command.StringFlag("$MBF_CACHE_DIR"),
+		"Directory to store cured artifacts",
+	).Flag(
+		&flagIdle,
+		"sched-idle", command.BoolFlag(false),
+		"Set SCHED_IDLE scheduling policy",
+	).Flag(
+		&flagHostAbstract,
+		"host-abstract", command.BoolFlag(
+			os.Getenv("MBF_HOST_ABSTRACT") != "",
+		),
+		"Do not restrict networked cure containers from connecting to host "+
+			"abstract UNIX sockets",
+	)
+
+	{
+		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 cache.Scrub(runtime.NumCPU() << flagShifts)
+			},
+		).Flag(
+			&flagShifts,
+			"shift", command.IntFlag(12),
+			"Scrub parallelism size exponent, to the power of 2",
+		)
+	}
+
+	{
+		var (
+			flagStatus bool
+			flagReport string
+		)
+		c.NewCommand(
+			"info",
+			"Display out-of-band metadata of an artifact",
+			func(args []string) (err error) {
+				if len(args) == 0 {
+					return errors.New("info requires at least 1 argument")
+				}
+
+				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)()
+				}
+
+				for i, name := range args {
+					if p, ok := rosa.ResolveName(name); !ok {
+						return fmt.Errorf("unknown artifact %q", name)
+					} else {
+						var suffix string
+						if version := rosa.Std.Version(p); version != rosa.Unversioned {
+							suffix += "-" + version
+						}
+						fmt.Println("name        : " + name + suffix)
+
+						meta := rosa.GetMetadata(p)
+						fmt.Println("description : " + meta.Description)
+						if meta.Website != "" {
+							fmt.Println("website     : " +
+								strings.TrimSuffix(meta.Website, "/"))
+						}
+						if len(meta.Dependencies) > 0 {
+							fmt.Print("depends on  :")
+							for _, d := range meta.Dependencies {
+								s := rosa.GetMetadata(d).Name
+								if version := rosa.Std.Version(d); version != rosa.Unversioned {
+									s += "-" + version
+								}
+								fmt.Print(" " + s)
+							}
+							fmt.Println()
+						}
+
+						const statusPrefix = "status      : "
+						if flagStatus {
+							if r == nil {
+								var f io.ReadSeekCloser
+								f, err = cache.OpenStatus(rosa.Std.Load(p))
+								if err != nil {
+									if errors.Is(err, os.ErrNotExist) {
+										fmt.Println(
+											statusPrefix + "not yet cured",
+										)
+									} else {
+										return
+									}
+								} else {
+									fmt.Print(statusPrefix)
+									_, err = io.Copy(os.Stdout, f)
+									if err = errors.Join(err, f.Close()); err != nil {
+										return
+									}
+								}
+							} else {
+								status, n := r.ArtifactOf(cache.Ident(rosa.Std.Load(p)))
+								if status == nil {
+									fmt.Println(
+										statusPrefix + "not in report",
+									)
+								} else {
+									fmt.Println("size        :", n)
+									fmt.Print(statusPrefix)
+									if _, err = os.Stdout.Write(status); err != nil {
+										return
+									}
+								}
+							}
+						}
+
+						if i != len(args)-1 {
+							fmt.Println()
+						}
+					}
+				}
+				return nil
+			},
+		).
+			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 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.PArtifact)
+			var wg sync.WaitGroup
+			for range max(flagJobs, 1) {
+				wg.Go(func() {
+					for p := range w {
+						meta := rosa.GetMetadata(p)
+						if meta.ID == 0 {
+							continue
+						}
+
+						v, err := meta.GetVersions(ctx)
+						if err != nil {
+							errsMu.Lock()
+							errs = append(errs, err)
+							errsMu.Unlock()
+							continue
+						}
+
+						if current, latest :=
+							rosa.Std.Version(p),
+							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 i := range rosa.PresetEnd {
+				select {
+				case w <- rosa.PArtifact(i):
+					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",
+			)
+	}
+
+	{
+		var (
+			flagGentoo   string
+			flagChecksum string
+
+			flagStage0 bool
+		)
+		c.NewCommand(
+			"stage3",
+			"Check for toolchain 3-stage non-determinism",
+			func(args []string) (err error) {
+				t := rosa.Std
+				if flagGentoo != "" {
+					t -= 3 // magic number to discourage misuse
+
+					var checksum pkg.Checksum
+					if len(flagChecksum) != 0 {
+						if err = pkg.Decode(&checksum, flagChecksum); err != nil {
+							return
+						}
+					}
+					rosa.SetGentooStage3(flagGentoo, checksum)
+				}
+
+				_, _, _, stage1 := (t - 2).NewLLVM()
+				_, _, _, stage2 := (t - 1).NewLLVM()
+				_, _, _, stage3 := t.NewLLVM()
+				var (
+					pathname *check.Absolute
+					checksum [2]unique.Handle[pkg.Checksum]
+				)
+
+				if pathname, _, err = cache.Cure(stage1); err != nil {
+					return err
+				}
+				log.Println("stage1:", pathname)
+
+				if pathname, checksum[0], err = cache.Cure(stage2); err != nil {
+					return err
+				}
+				log.Println("stage2:", pathname)
+				if pathname, checksum[1], err = cache.Cure(stage3); err != nil {
+					return err
+				}
+				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 pathname, _, err = cache.Cure(
+						t.Load(rosa.Stage0),
+					); err != nil {
+						return err
+					}
+					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
+		)
+		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")
+				}
+				p, ok := rosa.ResolveName(args[0])
+				if !ok {
+					return fmt.Errorf("unknown artifact %q", args[0])
+				}
+
+				switch {
+				default:
+					pathname, _, err := cache.Cure(rosa.Std.Load(p))
+					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 = cache.EncodeAll(f, rosa.Std.Load(p)); err != nil {
+						_ = f.Close()
+						return err
+					}
+
+					return f.Close()
+
+				case flagEnter:
+					return cache.EnterExec(
+						ctx,
+						rosa.Std.Load(p),
+						true, os.Stdin, os.Stdout, os.Stderr,
+						rosa.AbsSystem.Append("bin", "mksh"),
+						"sh",
+					)
+				}
+			},
+		).
+			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",
+			)
+	}
+
+	{
+		var (
+			flagNet     bool
+			flagSession bool
+
+			flagWithToolchain bool
+		)
+		c.NewCommand(
+			"shell",
+			"Interactive shell in the specified Rosa OS environment",
+			func(args []string) error {
+				presets := make([]rosa.PArtifact, len(args))
+				for i, arg := range args {
+					p, ok := rosa.ResolveName(arg)
+					if !ok {
+						return fmt.Errorf("unknown artifact %q", arg)
+					}
+					presets[i] = p
+				}
+				root := make(pkg.Collect, 0, 6+len(args))
+				root = rosa.Std.AppendPresets(root, presets...)
+
+				if flagWithToolchain {
+					musl, compilerRT, runtimes, clang := (rosa.Std - 1).NewLLVM()
+					root = append(root, musl, compilerRT, runtimes, clang)
+				} else {
+					root = append(root, rosa.Std.Load(rosa.Musl))
+				}
+				root = append(root,
+					rosa.Std.Load(rosa.Mksh),
+					rosa.Std.Load(rosa.Toybox),
+				)
+
+				if _, _, err := cache.Cure(&root); 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 {
+					pathname, checksum, err := cache.Cure(a)
+					if err != nil {
+						return err
+					}
+					cured[a] = cureRes{pathname, checksum}
+				}
+
+				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(cache.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
+				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) {
+		if cache != nil {
+			cache.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/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 +1,41 @@
+{ 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 = {
+    diskSize = 6 * 1024;
+
+    qemu.options = [
+      # Increase test performance:
+      "-smp 8"
+    ];
+  };
+
+  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 '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")

container/autoetc.go

@@ -4,14 +4,13 @@ import (
 	"encoding/gob"
 	"fmt"
 
-	"hakurei.app/container/check"
-	"hakurei.app/container/fhs"
+	"hakurei.app/check"
+	"hakurei.app/fhs"
 )
 
 func init() { gob.Register(new(AutoEtcOp)) }
 
-// Etc appends an [Op] that 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.
+// 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)
@@ -20,6 +19,9 @@ func (f *Ops) Etc(host *check.Absolute, prefix string) *Ops {
 	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 }

container/autoetc_test.go

@@ -5,8 +5,8 @@ import (
 	"os"
 	"testing"
 
-	"hakurei.app/container/check"
-	"hakurei.app/container/stub"
+	"hakurei.app/check"
+	"hakurei.app/internal/stub"
 )
 
 func TestAutoEtcOp(t *testing.T) {

container/autoroot.go

@@ -4,20 +4,22 @@ import (
 	"encoding/gob"
 	"fmt"
 
-	"hakurei.app/container/check"
-	"hakurei.app/container/fhs"
+	"hakurei.app/check"
+	"hakurei.app/fhs"
 	"hakurei.app/message"
 )
 
 func init() { gob.Register(new(AutoRootOp)) }
 
-// Root appends an [Op] that 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.
+// 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

container/autoroot_test.go

@@ -5,9 +5,9 @@ import (
 	"os"
 	"testing"
 
-	"hakurei.app/container/check"
+	"hakurei.app/check"
 	"hakurei.app/container/std"
-	"hakurei.app/container/stub"
+	"hakurei.app/internal/stub"
 	"hakurei.app/message"
 )
 
@@ -202,7 +202,7 @@ func TestIsAutoRootBindable(t *testing.T) {
 			t.Parallel()
 			var msg message.Msg
 			if tc.log {
-				msg = &kstub{nil, stub.New(t, func(s *stub.Stub[syscallDispatcher]) syscallDispatcher { panic("unreachable") }, stub.Expect{Calls: []stub.Call{
+				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),
 				}})}
 			}

container/capability.go

@@ -3,6 +3,8 @@ package container
 import (
 	"syscall"
 	"unsafe"
+
+	"hakurei.app/ext"
 )
 
 const (
@@ -14,6 +16,7 @@ const (
 
 	CAP_SYS_ADMIN    = 0x15
 	CAP_SETPCAP      = 0x8
+	CAP_NET_ADMIN    = 0xc
 	CAP_DAC_OVERRIDE = 0x1
 )
 
@@ -49,10 +52,16 @@ func capset(hdrp *capHeader, datap *[2]capData) error {
 }
 
 // capBoundingSetDrop drops a capability from the calling thread's capability bounding set.
-func capBoundingSetDrop(cap uintptr) error { return Prctl(syscall.PR_CAPBSET_DROP, cap, 0) }
+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 Prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_CLEAR_ALL, 0) }
+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 Prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_RAISE, cap) }
+func capAmbientRaise(cap uintptr) error {
+	return ext.Prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_RAISE, cap)
+}

container/check/absolute.go

@@ -1,104 +0,0 @@
-// Package check provides types yielding values checked to meet a condition.
-package check
-
-import (
-	"encoding/json"
-	"errors"
-	"fmt"
-	"path"
-	"slices"
-	"strings"
-	"syscall"
-)
-
-// AbsoluteError is returned by [NewAbs] and holds the invalid pathname.
-type AbsoluteError struct{ Pathname string }
-
-func (e *AbsoluteError) Error() string { return fmt.Sprintf("path %q is not absolute", e.Pathname) }
-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 string }
-
-// unsafeAbs returns [check.Absolute] on any string value.
-func unsafeAbs(pathname string) *Absolute { return &Absolute{pathname} }
-
-func (a *Absolute) String() string {
-	if a.pathname == "" {
-		panic("attempted use of zero Absolute")
-	}
-	return a.pathname
-}
-
-func (a *Absolute) Is(v *Absolute) bool {
-	if a == nil && v == nil {
-		return true
-	}
-	return a != nil && v != nil &&
-		a.pathname != "" && v.pathname != "" &&
-		a.pathname == v.pathname
-}
-
-// NewAbs checks pathname and returns a new [Absolute] if pathname is absolute.
-func NewAbs(pathname string) (*Absolute, error) {
-	if !path.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 [path.Join] with [Absolute] as the first element.
-func (a *Absolute) Append(elem ...string) *Absolute {
-	return unsafeAbs(path.Join(append([]string{a.String()}, elem...)...))
-}
-
-// Dir calls [path.Dir] with [Absolute] as its argument.
-func (a *Absolute) Dir() *Absolute { return unsafeAbs(path.Dir(a.String())) }
-
-func (a *Absolute) GobEncode() ([]byte, error) { return []byte(a.String()), nil }
-func (a *Absolute) GobDecode(data []byte) error {
-	pathname := string(data)
-	if !path.IsAbs(pathname) {
-		return &AbsoluteError{pathname}
-	}
-	a.pathname = pathname
-	return nil
-}
-
-func (a *Absolute) MarshalJSON() ([]byte, error) { return json.Marshal(a.String()) }
-func (a *Absolute) UnmarshalJSON(data []byte) error {
-	var pathname string
-	if err := json.Unmarshal(data, &pathname); err != nil {
-		return err
-	}
-	if !path.IsAbs(pathname) {
-		return &AbsoluteError{pathname}
-	}
-	a.pathname = pathname
-	return nil
-}
-
-// 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.String() == b.String() })
-}

container/container.go

@@ -1,4 +1,5 @@
-// Package container implements unprivileged Linux containers with built-in support for syscall filtering.
+// Package container implements unprivileged Linux containers with built-in
+// support for syscall filtering.
 package container
 
 import (
@@ -15,10 +16,11 @@ import (
 	. "syscall"
 	"time"
 
-	"hakurei.app/container/check"
-	"hakurei.app/container/fhs"
+	"hakurei.app/check"
 	"hakurei.app/container/seccomp"
 	"hakurei.app/container/std"
+	"hakurei.app/ext"
+	"hakurei.app/fhs"
 	"hakurei.app/message"
 )
 
@@ -26,33 +28,42 @@ const (
 	// CancelSignal is the signal expected by container init on context cancel.
 	// A custom [Container.Cancel] function must eventually deliver this signal.
 	CancelSignal = SIGUSR2
-
-	// Timeout for writing initParams to Container.setup.
-	initSetupTimeout = 5 * time.Second
 )
 
 type (
 	// Container represents a container environment being prepared or run.
 	// None of [Container] methods are safe for concurrent use.
 	Container struct {
+		// Whether the container init should stay alive after its parent terminates.
+		AllowOrphan bool
+		// Whether to set SchedPolicy and SchedPriority via sched_setscheduler(2).
+		SetScheduler bool
+		// Scheduling policy to set via sched_setscheduler(2).
+		SchedPolicy ext.SchedPolicy
+		// Scheduling priority to set via sched_setscheduler(2). The zero value
+		// implies the minimum value supported by the current SchedPolicy.
+		SchedPriority ext.Int
 		// Cgroup fd, nil to disable.
 		Cgroup *int
-		// ExtraFiles passed through to initial process in the container,
-		// with behaviour identical to its [exec.Cmd] counterpart.
+		// ExtraFiles passed through to initial process in the container, with
+		// behaviour identical to its [exec.Cmd] counterpart.
 		ExtraFiles []*os.File
 
-		// param pipe for shim and init
-		setup *os.File
-		// cancels cmd
+		// Write end of a pipe connected to the init to deliver [Params].
+		setup [2]*os.File
+		// Cancels the context passed to the underlying cmd.
 		cancel context.CancelFunc
-		// closed after Wait returns
+		// Closed after Wait returns. Keeps the spawning thread alive.
 		wait chan struct{}
 
 		Stdin  io.Reader
 		Stdout io.Writer
 		Stderr io.Writer
 
-		Cancel    func(cmd *exec.Cmd) error
+		// Custom cancellation behaviour for the underlying [exec.Cmd]. Must
+		// deliver [CancelSignal] before returning.
+		Cancel func(cmd *exec.Cmd) error
+		// Copied to the underlying [exec.Cmd].
 		WaitDelay time.Duration
 
 		cmd *exec.Cmd
@@ -172,31 +183,24 @@ var (
 	closeOnExecErr  error
 )
 
-// ensureCloseOnExec ensures all currently open file descriptors have the syscall.FD_CLOEXEC flag set.
-// This is only ran once as it is intended to handle files left open by the parent, and any file opened
-// on this side should already have syscall.FD_CLOEXEC set.
+// ensureCloseOnExec ensures all currently open file descriptors have the
+// syscall.FD_CLOEXEC flag set.
+//
+// This is only ran once as it is intended to handle files left open by the
+// parent, and any file opened on this side should already have
+// syscall.FD_CLOEXEC set.
 func ensureCloseOnExec() error {
-	closeOnExecOnce.Do(func() {
-		const fdPrefixPath = "/proc/self/fd/"
-
-		var entries []os.DirEntry
-		if entries, closeOnExecErr = os.ReadDir(fdPrefixPath); closeOnExecErr != nil {
-			return
-		}
-
-		var fd int
-		for _, ent := range entries {
-			if fd, closeOnExecErr = strconv.Atoi(ent.Name()); closeOnExecErr != nil {
-				break // not reached
-			}
-			CloseOnExec(fd)
-		}
-	})
+	closeOnExecOnce.Do(func() { closeOnExecErr = doCloseOnExec() })
 
 	if closeOnExecErr == nil {
 		return nil
 	}
-	return &StartError{Fatal: true, Step: "set FD_CLOEXEC on all open files", Err: closeOnExecErr, Passthrough: true}
+	return &StartError{
+		Fatal:       true,
+		Step:        "set FD_CLOEXEC on all open files",
+		Err:         closeOnExecErr,
+		Passthrough: true,
+	}
 }
 
 // Start starts the container init. The init process blocks until Serve is called.
@@ -252,8 +256,7 @@ func (p *Container) Start() error {
 	}
 	p.cmd.Dir = fhs.Root
 	p.cmd.SysProcAttr = &SysProcAttr{
-		Setsid:    !p.RetainSession,
-		Pdeathsig: SIGKILL,
+		Setsid: !p.RetainSession,
 		Cloneflags: CLONE_NEWUSER | CLONE_NEWPID | CLONE_NEWNS |
 			CLONE_NEWIPC | CLONE_NEWUTS | CLONE_NEWCGROUP,
 
@@ -262,12 +265,17 @@ func (p *Container) Start() error {
 			CAP_SYS_ADMIN,
 			// drop capabilities
 			CAP_SETPCAP,
+			// bring up loopback interface
+			CAP_NET_ADMIN,
 			// overlay access to upperdir and workdir
 			CAP_DAC_OVERRIDE,
 		},
 
 		UseCgroupFD: p.Cgroup != nil,
 	}
+	if !p.AllowOrphan {
+		p.cmd.SysProcAttr.Pdeathsig = SIGKILL
+	}
 	if p.cmd.SysProcAttr.UseCgroupFD {
 		p.cmd.SysProcAttr.CgroupFD = *p.Cgroup
 	}
@@ -276,10 +284,16 @@ func (p *Container) Start() error {
 	}
 
 	// place setup pipe before user supplied extra files, this is later restored by init
-	if fd, f, err := Setup(&p.cmd.ExtraFiles); err != nil {
-		return &StartError{true, "set up params stream", err, false, false}
+	if r, w, err := os.Pipe(); err != nil {
+		return &StartError{
+			Fatal: true,
+			Step:  "set up params stream",
+			Err:   err,
+		}
 	} else {
-		p.setup = f
+		fd := 3 + len(p.cmd.ExtraFiles)
+		p.cmd.ExtraFiles = append(p.cmd.ExtraFiles, r)
+		p.setup[0], p.setup[1] = r, w
 		p.cmd.Env = []string{setupEnv + "=" + strconv.Itoa(fd)}
 	}
 	p.cmd.ExtraFiles = append(p.cmd.ExtraFiles, p.ExtraFiles...)
@@ -289,10 +303,16 @@ func (p *Container) Start() error {
 		runtime.LockOSThread()
 		p.wait = make(chan struct{})
 
-		done <- func() error { // setup depending on per-thread state must happen here
-			// PR_SET_NO_NEW_PRIVS: depends on per-thread state but acts on all processes created from that thread
+		// setup depending on per-thread state must happen here
+		done <- func() error {
+			// PR_SET_NO_NEW_PRIVS: thread-directed but acts on all processes
+			// created from the calling thread
 			if err := SetNoNewPrivs(); err != nil {
-				return &StartError{true, "prctl(PR_SET_NO_NEW_PRIVS)", err, false, false}
+				return &StartError{
+					Fatal: true,
+					Step:  "prctl(PR_SET_NO_NEW_PRIVS)",
+					Err:   err,
+				}
 			}
 
 			// landlock: depends on per-thread state but acts on a process group
@@ -303,29 +323,41 @@ func (p *Container) Start() error {
 				}
 
 				if abi, err := LandlockGetABI(); err != nil {
-					if p.HostAbstract {
-						// landlock can be skipped here as it restricts access to resources
-						// already covered by namespaces (pid)
+					if p.HostAbstract || !p.HostNet {
+						// landlock can be skipped here as it restricts access
+						// to resources already covered by namespaces (pid, net)
 						goto landlockOut
 					}
-					return &StartError{false, "get landlock ABI", err, false, false}
+					return &StartError{Step: "get landlock ABI", Err: err}
 				} else if abi < 6 {
 					if p.HostAbstract {
 						// see above comment
 						goto landlockOut
 					}
-					return &StartError{false, "kernel version too old for LANDLOCK_SCOPE_ABSTRACT_UNIX_SOCKET", ENOSYS, true, false}
+					return &StartError{
+						Step:   "kernel too old for LANDLOCK_SCOPE_ABSTRACT_UNIX_SOCKET",
+						Err:    ENOSYS,
+						Origin: true,
+					}
 				} else {
 					p.msg.Verbosef("landlock abi version %d", abi)
 				}
 
 				if rulesetFd, err := rulesetAttr.Create(0); err != nil {
-					return &StartError{true, "create landlock ruleset", err, false, false}
+					return &StartError{
+						Fatal: true,
+						Step:  "create landlock ruleset",
+						Err:   err,
+					}
 				} else {
 					p.msg.Verbosef("enforcing landlock ruleset %s", rulesetAttr)
 					if err = LandlockRestrictSelf(rulesetFd, 0); err != nil {
 						_ = Close(rulesetFd)
-						return &StartError{true, "enforce landlock ruleset", err, false, false}
+						return &StartError{
+							Fatal: true,
+							Step:  "enforce landlock ruleset",
+							Err:   err,
+						}
 					}
 					if err = Close(rulesetFd); err != nil {
 						p.msg.Verbosef("cannot close landlock ruleset: %v", err)
@@ -336,9 +368,52 @@ func (p *Container) Start() error {
 			landlockOut:
 			}
 
+			// sched_setscheduler: thread-directed but acts on all processes
+			// created from the calling thread
+			if p.SetScheduler {
+				if p.SchedPolicy < 0 || p.SchedPolicy > ext.SCHED_LAST {
+					return &StartError{
+						Fatal: false,
+						Step:  "set scheduling policy",
+						Err:   EINVAL,
+					}
+				}
+
+				var param schedParam
+				if priority, err := p.SchedPolicy.GetPriorityMin(); err != nil {
+					return &StartError{
+						Fatal: true,
+						Step:  "get minimum priority",
+						Err:   err,
+					}
+				} else {
+					param.priority = max(priority, p.SchedPriority)
+				}
+
+				p.msg.Verbosef(
+					"setting scheduling policy %s priority %d",
+					p.SchedPolicy, param.priority,
+				)
+				if err := schedSetscheduler(
+					0, // calling thread
+					p.SchedPolicy,
+					&param,
+				); err != nil {
+					return &StartError{
+						Fatal: true,
+						Step:  "set scheduling policy",
+						Err:   err,
+					}
+				}
+			}
+
 			p.msg.Verbose("starting container init")
 			if err := p.cmd.Start(); err != nil {
-				return &StartError{false, "start container init", err, false, true}
+				return &StartError{
+					Step:        "start container init",
+					Err:         err,
+					Passthrough: true,
+				}
 			}
 			return nil
 		}()
@@ -350,21 +425,40 @@ func (p *Container) Start() error {
 }
 
 // Serve serves [Container.Params] to the container init.
+//
 // Serve must only be called once.
-func (p *Container) Serve() error {
-	if p.setup == nil {
+func (p *Container) Serve() (err error) {
+	if p.setup[0] == nil || p.setup[1] == nil {
 		panic("invalid serve")
 	}
 
-	setup := p.setup
-	p.setup = nil
-	if err := setup.SetDeadline(time.Now().Add(initSetupTimeout)); err != nil {
-		return &StartError{true, "set init pipe deadline", err, false, true}
+	done := make(chan struct{})
+	defer func() {
+		if closeErr := p.setup[1].Close(); err == nil {
+			err = closeErr
+		}
+
+		if err != nil {
+			p.cancel()
+		}
+		close(done)
+		p.setup[0], p.setup[1] = nil, nil
+	}()
+	if err = p.setup[0].Close(); err != nil {
+		return &StartError{
+			Fatal:       true,
+			Step:        "close read end of init pipe",
+			Err:         err,
+			Passthrough: true,
+		}
 	}
 
 	if p.Path == nil {
-		p.cancel()
-		return &StartError{false, "invalid executable pathname", EINVAL, true, false}
+		return &StartError{
+			Step:   "invalid executable pathname",
+			Err:    EINVAL,
+			Origin: true,
+		}
 	}
 
 	// do not transmit nil
@@ -375,21 +469,31 @@ func (p *Container) Serve() error {
 		p.SeccompRules = make([]std.NativeRule, 0)
 	}
 
-	err := gob.NewEncoder(setup).Encode(&initParams{
+	t := time.Now().UTC()
+	go func(f *os.File) {
+		select {
+		case <-p.ctx.Done():
+			if cancelErr := f.SetWriteDeadline(t); cancelErr != nil {
+				p.msg.Verbose(err)
+			}
+
+		case <-done:
+			p.msg.Verbose("setup payload took", time.Since(t))
+			return
+		}
+	}(p.setup[1])
+
+	return gob.NewEncoder(p.setup[1]).Encode(&initParams{
 		p.Params,
 		Getuid(),
 		Getgid(),
 		len(p.ExtraFiles),
 		p.msg.IsVerbose(),
 	})
-	_ = setup.Close()
-	if err != nil {
-		p.cancel()
-	}
-	return err
 }
 
-// Wait waits for the container init process to exit and releases any resources associated with the [Container].
+// Wait blocks until the container init process to exit and releases any
+// resources associated with the [Container].
 func (p *Container) Wait() error {
 	if p.cmd == nil || p.cmd.Process == nil {
 		return EINVAL
@@ -434,11 +538,13 @@ func (p *Container) StderrPipe() (r io.ReadCloser, err error) {
 }
 
 func (p *Container) String() string {
-	return fmt.Sprintf("argv: %q, filter: %v, rules: %d, flags: %#x, presets: %#x",
-		p.Args, !p.SeccompDisable, len(p.SeccompRules), int(p.SeccompFlags), int(p.SeccompPresets))
+	return fmt.Sprintf(
+		"argv: %q, filter: %v, rules: %d, flags: %#x, presets: %#x",
+		p.Args, !p.SeccompDisable, len(p.SeccompRules), int(p.SeccompFlags), int(p.SeccompPresets),
+	)
 }
 
-// ProcessState returns the address to os.ProcessState held by the underlying [exec.Cmd].
+// ProcessState returns the address of os.ProcessState held by the underlying [exec.Cmd].
 func (p *Container) ProcessState() *os.ProcessState {
 	if p.cmd == nil {
 		return nil
@@ -446,7 +552,8 @@ func (p *Container) ProcessState() *os.ProcessState {
 	return p.cmd.ProcessState
 }
 
-// New returns the address to a new instance of [Container] that requires further initialisation before use.
+// New returns the address to a new instance of [Container]. This value requires
+// further initialisation before use.
 func New(ctx context.Context, msg message.Msg) *Container {
 	if msg == nil {
 		msg = message.New(nil)
@@ -455,12 +562,18 @@ func New(ctx context.Context, msg message.Msg) *Container {
 	p := &Container{ctx: ctx, msg: msg, Params: Params{Ops: new(Ops)}}
 	c, cancel := context.WithCancel(ctx)
 	p.cancel = cancel
-	p.cmd = exec.CommandContext(c, MustExecutable(msg))
+	p.cmd = exec.CommandContext(c, fhs.ProcSelfExe)
 	return p
 }
 
 // NewCommand calls [New] and initialises the [Params.Path] and [Params.Args] fields.
-func NewCommand(ctx context.Context, msg message.Msg, pathname *check.Absolute, name string, args ...string) *Container {
+func NewCommand(
+	ctx context.Context,
+	msg message.Msg,
+	pathname *check.Absolute,
+	name string,
+	args ...string,
+) *Container {
 	z := New(ctx, msg)
 	z.Path = pathname
 	z.Args = append([]string{name}, args...)

container/container_test.go

@@ -16,18 +16,20 @@ import (
 	"strings"
 	"syscall"
 	"testing"
-	"time"
 
+	"hakurei.app/check"
 	"hakurei.app/command"
 	"hakurei.app/container"
-	"hakurei.app/container/check"
-	"hakurei.app/container/fhs"
 	"hakurei.app/container/seccomp"
 	"hakurei.app/container/std"
-	"hakurei.app/container/vfs"
+	"hakurei.app/ext"
+	"hakurei.app/fhs"
 	"hakurei.app/hst"
+	"hakurei.app/internal/info"
+	"hakurei.app/internal/params"
 	"hakurei.app/ldd"
 	"hakurei.app/message"
+	"hakurei.app/vfs"
 )
 
 // Note: this package requires cgo, which is unavailable in the Go playground.
@@ -83,9 +85,9 @@ func TestStartError(t *testing.T) {
 		{"params env", &container.StartError{
 			Fatal: true,
 			Step:  "set up params stream",
-			Err:   container.ErrReceiveEnv,
+			Err:   params.ErrReceiveEnv,
 		}, "set up params stream: environment variable not set",
-			container.ErrReceiveEnv, syscall.EBADF,
+			params.ErrReceiveEnv, syscall.EBADF,
 			"cannot set up params stream: environment variable not set"},
 
 		{"params", &container.StartError{
@@ -258,7 +260,7 @@ var containerTestCases = []struct {
 		1000, 100, nil, 0, std.PresetExt},
 	{"custom rules", true, true, true, false,
 		emptyOps, emptyMnt,
-		1, 31, []std.NativeRule{{Syscall: std.ScmpSyscall(syscall.SYS_SETUID), Errno: std.ScmpErrno(syscall.EPERM)}}, 0, std.PresetExt},
+		1, 31, []std.NativeRule{{Syscall: ext.SyscallNum(syscall.SYS_SETUID), Errno: std.ScmpErrno(syscall.EPERM)}}, 0, std.PresetExt},
 
 	{"tmpfs", true, false, false, true,
 		earlyOps(new(container.Ops).
@@ -274,13 +276,13 @@ var containerTestCases = []struct {
 			Dev(check.MustAbs("/dev"), true),
 		),
 		earlyMnt(
-			ent("/", "/dev", "ro,nosuid,nodev,relatime", "tmpfs", "devtmpfs", ignore),
-			ent("/null", "/dev/null", "rw,nosuid", "devtmpfs", "devtmpfs", ignore),
-			ent("/zero", "/dev/zero", "rw,nosuid", "devtmpfs", "devtmpfs", ignore),
-			ent("/full", "/dev/full", "rw,nosuid", "devtmpfs", "devtmpfs", ignore),
-			ent("/random", "/dev/random", "rw,nosuid", "devtmpfs", "devtmpfs", ignore),
-			ent("/urandom", "/dev/urandom", "rw,nosuid", "devtmpfs", "devtmpfs", ignore),
-			ent("/tty", "/dev/tty", "rw,nosuid", "devtmpfs", "devtmpfs", ignore),
+			ent("/", "/dev", "ro,nosuid,nodev,relatime", "tmpfs", ignore, ignore),
+			ent("/null", "/dev/null", ignore, "devtmpfs", ignore, ignore),
+			ent("/zero", "/dev/zero", ignore, "devtmpfs", ignore, ignore),
+			ent("/full", "/dev/full", ignore, "devtmpfs", ignore, ignore),
+			ent("/random", "/dev/random", ignore, "devtmpfs", ignore, ignore),
+			ent("/urandom", "/dev/urandom", ignore, "devtmpfs", ignore, ignore),
+			ent("/tty", "/dev/tty", ignore, "devtmpfs", ignore, ignore),
 			ent("/", "/dev/pts", "rw,nosuid,noexec,relatime", "devpts", "devpts", "rw,mode=620,ptmxmode=666"),
 			ent("/", "/dev/mqueue", "rw,nosuid,nodev,noexec,relatime", "mqueue", "mqueue", "rw"),
 			ent("/", "/dev/shm", "rw,nosuid,nodev,relatime", "tmpfs", "tmpfs", ignore),
@@ -292,13 +294,13 @@ var containerTestCases = []struct {
 			Dev(check.MustAbs("/dev"), false),
 		),
 		earlyMnt(
-			ent("/", "/dev", "ro,nosuid,nodev,relatime", "tmpfs", "devtmpfs", ignore),
-			ent("/null", "/dev/null", "rw,nosuid", "devtmpfs", "devtmpfs", ignore),
-			ent("/zero", "/dev/zero", "rw,nosuid", "devtmpfs", "devtmpfs", ignore),
-			ent("/full", "/dev/full", "rw,nosuid", "devtmpfs", "devtmpfs", ignore),
-			ent("/random", "/dev/random", "rw,nosuid", "devtmpfs", "devtmpfs", ignore),
-			ent("/urandom", "/dev/urandom", "rw,nosuid", "devtmpfs", "devtmpfs", ignore),
-			ent("/tty", "/dev/tty", "rw,nosuid", "devtmpfs", "devtmpfs", ignore),
+			ent("/", "/dev", "ro,nosuid,nodev,relatime", "tmpfs", ignore, ignore),
+			ent("/null", "/dev/null", ignore, "devtmpfs", ignore, ignore),
+			ent("/zero", "/dev/zero", ignore, "devtmpfs", ignore, ignore),
+			ent("/full", "/dev/full", ignore, "devtmpfs", ignore, ignore),
+			ent("/random", "/dev/random", ignore, "devtmpfs", ignore, ignore),
+			ent("/urandom", "/dev/urandom", ignore, "devtmpfs", ignore, ignore),
+			ent("/tty", "/dev/tty", ignore, "devtmpfs", ignore, ignore),
 			ent("/", "/dev/pts", "rw,nosuid,noexec,relatime", "devpts", "devpts", "rw,mode=620,ptmxmode=666"),
 			ent("/", "/dev/shm", "rw,nosuid,nodev,relatime", "tmpfs", "tmpfs", ignore),
 		),
@@ -435,11 +437,8 @@ func TestContainer(t *testing.T) {
 			wantOps, wantOpsCtx := tc.ops(t)
 			wantMnt := tc.mnt(t, wantOpsCtx)
 
-			ctx, cancel := context.WithTimeout(t.Context(), helperDefaultTimeout)
-			defer cancel()
-
 			var libPaths []*check.Absolute
-			c := helperNewContainerLibPaths(ctx, &libPaths, "container", strconv.Itoa(i))
+			c := helperNewContainerLibPaths(t.Context(), &libPaths, "container", strconv.Itoa(i))
 			c.Uid = tc.uid
 			c.Gid = tc.gid
 			c.Hostname = hostnameFromTestCase(tc.name)
@@ -449,7 +448,6 @@ func TestContainer(t *testing.T) {
 			} else {
 				c.Stdout, c.Stderr = os.Stdout, os.Stderr
 			}
-			c.WaitDelay = helperDefaultTimeout
 			*c.Ops = append(*c.Ops, *wantOps...)
 			c.SeccompRules = tc.rules
 			c.SeccompFlags = tc.flags | seccomp.AllowMultiarch
@@ -457,6 +455,15 @@ func TestContainer(t *testing.T) {
 			c.SeccompDisable = !tc.filter
 			c.RetainSession = tc.session
 			c.HostNet = tc.net
+			if info.CanDegrade {
+				if _, err := container.LandlockGetABI(); err != nil {
+					if !errors.Is(err, syscall.ENOSYS) {
+						t.Fatalf("LandlockGetABI: error = %v", err)
+					}
+					c.HostAbstract = true
+					t.Log("Landlock LSM is unavailable, enabling HostAbstract")
+				}
+			}
 
 			c.
 				Readonly(check.MustAbs(pathReadonly), 0755).
@@ -552,11 +559,10 @@ func testContainerCancel(
 ) func(t *testing.T) {
 	return func(t *testing.T) {
 		t.Parallel()
-		ctx, cancel := context.WithTimeout(t.Context(), helperDefaultTimeout)
+		ctx, cancel := context.WithCancel(t.Context())
 
 		c := helperNewContainer(ctx, "block")
 		c.Stdout, c.Stderr = os.Stdout, os.Stderr
-		c.WaitDelay = helperDefaultTimeout
 		if containerExtra != nil {
 			containerExtra(c)
 		}
@@ -690,11 +696,22 @@ func init() {
 						return fmt.Errorf("got more than %d entries", len(mnt))
 					}
 
-					// ugly hack but should be reliable and is less likely to false negative than comparing by parsed flags
-					cur.VfsOptstr = strings.TrimSuffix(cur.VfsOptstr, ",relatime")
-					cur.VfsOptstr = strings.TrimSuffix(cur.VfsOptstr, ",noatime")
-					mnt[i].VfsOptstr = strings.TrimSuffix(mnt[i].VfsOptstr, ",relatime")
-					mnt[i].VfsOptstr = strings.TrimSuffix(mnt[i].VfsOptstr, ",noatime")
+					// ugly hack but should be reliable and is less likely to
+					//false negative than comparing by parsed flags
+					for _, s := range []string{
+						"relatime",
+						"noatime",
+					} {
+						cur.VfsOptstr = strings.TrimSuffix(cur.VfsOptstr, ","+s)
+						mnt[i].VfsOptstr = strings.TrimSuffix(mnt[i].VfsOptstr, ","+s)
+					}
+					for _, s := range []string{
+						"seclabel",
+						"inode64",
+					} {
+						cur.FsOptstr = strings.Replace(cur.FsOptstr, ","+s, "", 1)
+						mnt[i].FsOptstr = strings.Replace(mnt[i].FsOptstr, ","+s, "", 1)
+					}
 
 					if !cur.EqualWithIgnore(mnt[i], "\x00") {
 						fail = true
@@ -726,8 +743,7 @@ func init() {
 const (
 	envDoCheck = "HAKUREI_TEST_DO_CHECK"
 
-	helperDefaultTimeout = 5 * time.Second
-	helperInnerPath      = "/usr/bin/helper"
+	helperInnerPath = "/usr/bin/helper"
 )
 
 var (
@@ -762,14 +778,13 @@ func TestMain(m *testing.M) {
 func helperNewContainerLibPaths(ctx context.Context, libPaths *[]*check.Absolute, args ...string) (c *container.Container) {
 	msg := message.New(nil)
 	msg.SwapVerbose(testing.Verbose())
-	executable := check.MustAbs(container.MustExecutable(msg))
 
 	c = container.NewCommand(ctx, msg, absHelperInnerPath, "helper", args...)
 	c.Env = append(c.Env, envDoCheck+"=1")
-	c.Bind(executable, absHelperInnerPath, 0)
+	c.Bind(fhs.AbsProcSelfExe, absHelperInnerPath, 0)
 
 	// in case test has cgo enabled
-	if entries, err := ldd.Resolve(ctx, msg, executable); err != nil {
+	if entries, err := ldd.Resolve(ctx, msg, nil); err != nil {
 		log.Fatalf("ldd: %v", err)
 	} else {
 		*libPaths = ldd.Path(entries)

container/dispatcher.go

@@ -1,8 +1,10 @@
 package container
 
 import (
+	"context"
 	"io"
 	"io/fs"
+	"net"
 	"os"
 	"os/exec"
 	"os/signal"
@@ -12,6 +14,9 @@ import (
 
 	"hakurei.app/container/seccomp"
 	"hakurei.app/container/std"
+	"hakurei.app/ext"
+	"hakurei.app/internal/netlink"
+	"hakurei.app/internal/params"
 	"hakurei.app/message"
 )
 
@@ -21,7 +26,8 @@ type osFile interface {
 	fs.File
 }
 
-// syscallDispatcher provides methods that make state-dependent system calls as part of their behaviour.
+// syscallDispatcher provides methods that make state-dependent system calls as
+// part of their behaviour.
 type syscallDispatcher interface {
 	// new starts a goroutine with a new instance of syscallDispatcher.
 	// A syscallDispatcher must never be used in any goroutine other than the one owning it,
@@ -51,7 +57,7 @@ type syscallDispatcher interface {
 	// isatty provides [Isatty].
 	isatty(fd int) bool
 	// receive provides [Receive].
-	receive(key string, e any, fdp *uintptr) (closeFunc func() error, err error)
+	receive(key string, e any, fdp *int) (closeFunc func() error, err error)
 
 	// bindMount provides procPaths.bindMount.
 	bindMount(msg message.Msg, source, target string, flags uintptr) error
@@ -61,6 +67,8 @@ type syscallDispatcher interface {
 	mountTmpfs(fsname, target string, flags uintptr, size int, perm os.FileMode) error
 	// ensureFile provides ensureFile.
 	ensureFile(name string, perm, pperm os.FileMode) error
+	// mustLoopback provides mustLoopback.
+	mustLoopback(ctx context.Context, msg message.Msg)
 
 	// seccompLoad provides [seccomp.Load].
 	seccompLoad(rules []std.NativeRule, flags seccomp.ExportFlag) error
@@ -138,8 +146,8 @@ func (k direct) new(f func(k syscallDispatcher)) { go f(k) }
 
 func (direct) lockOSThread() { runtime.LockOSThread() }
 
-func (direct) setPtracer(pid uintptr) error       { return SetPtracer(pid) }
-func (direct) setDumpable(dumpable uintptr) error { return SetDumpable(dumpable) }
+func (direct) setPtracer(pid uintptr) error       { return ext.SetPtracer(pid) }
+func (direct) setDumpable(dumpable uintptr) error { return ext.SetDumpable(dumpable) }
 func (direct) setNoNewPrivs() error               { return SetNoNewPrivs() }
 
 func (direct) lastcap(msg message.Msg) uintptr                 { return LastCap(msg) }
@@ -147,9 +155,9 @@ func (direct) capset(hdrp *capHeader, datap *[2]capData) error { return capset(h
 func (direct) capBoundingSetDrop(cap uintptr) error            { return capBoundingSetDrop(cap) }
 func (direct) capAmbientClearAll() error                       { return capAmbientClearAll() }
 func (direct) capAmbientRaise(cap uintptr) error               { return capAmbientRaise(cap) }
-func (direct) isatty(fd int) bool                              { return Isatty(fd) }
-func (direct) receive(key string, e any, fdp *uintptr) (func() error, error) {
-	return Receive(key, e, fdp)
+func (direct) isatty(fd int) bool                              { return ext.Isatty(fd) }
+func (direct) receive(key string, e any, fdp *int) (func() error, error) {
+	return params.Receive(key, e, fdp)
 }
 
 func (direct) bindMount(msg message.Msg, source, target string, flags uintptr) error {
@@ -164,6 +172,50 @@ func (k direct) mountTmpfs(fsname, target string, flags uintptr, size int, perm
 func (direct) ensureFile(name string, perm, pperm os.FileMode) error {
 	return ensureFile(name, perm, pperm)
 }
+func (direct) mustLoopback(ctx context.Context, msg message.Msg) {
+	var lo int
+	if ifi, err := net.InterfaceByName("lo"); err != nil {
+		msg.GetLogger().Fatalln(err)
+	} else {
+		lo = ifi.Index
+	}
+
+	c, err := netlink.DialRoute(0)
+	if err != nil {
+		msg.GetLogger().Fatalln(err)
+	}
+
+	must := func(err error) {
+		if err == nil {
+			return
+		}
+		if closeErr := c.Close(); closeErr != nil {
+			msg.Verbosef("cannot close RTNETLINK: %v", closeErr)
+		}
+
+		switch err.(type) {
+		case *os.SyscallError:
+			msg.GetLogger().Fatalf("cannot %v", err)
+
+		case syscall.Errno:
+			msg.GetLogger().Fatalf("RTNETLINK answers: %v", err)
+
+		default:
+			if err == context.DeadlineExceeded || err == context.Canceled {
+				msg.GetLogger().Fatalf("interrupted RTNETLINK operation")
+			}
+			msg.GetLogger().Fatal("RTNETLINK answers with malformed message")
+		}
+	}
+	must(c.SendNewaddrLo(ctx, uint32(lo)))
+	must(c.SendIfInfomsg(ctx, syscall.RTM_NEWLINK, 0, &syscall.IfInfomsg{
+		Family: syscall.AF_UNSPEC,
+		Index:  int32(lo),
+		Flags:  syscall.IFF_UP,
+		Change: syscall.IFF_UP,
+	}))
+	must(c.Close())
+}
 
 func (direct) seccompLoad(rules []std.NativeRule, flags seccomp.ExportFlag) error {
 	return seccomp.Load(rules, flags)

container/dispatcher_test.go

@@ -2,6 +2,7 @@ package container
 
 import (
 	"bytes"
+	"context"
 	"fmt"
 	"io"
 	"io/fs"
@@ -18,7 +19,7 @@ import (
 
 	"hakurei.app/container/seccomp"
 	"hakurei.app/container/std"
-	"hakurei.app/container/stub"
+	"hakurei.app/internal/stub"
 	"hakurei.app/message"
 )
 
@@ -162,7 +163,8 @@ func checkSimple(t *testing.T, fname string, testCases []simpleTestCase) {
 			t.Parallel()
 
 			wait4signal := make(chan struct{})
-			k := &kstub{wait4signal, stub.New(t, func(s *stub.Stub[syscallDispatcher]) syscallDispatcher { return &kstub{wait4signal, s} }, tc.want)}
+			lockNotify := make(chan struct{})
+			k := &kstub{wait4signal, lockNotify, stub.New(t, func(s *stub.Stub[syscallDispatcher]) syscallDispatcher { return &kstub{wait4signal, lockNotify, s} }, tc.want)}
 			defer stub.HandleExit(t)
 			if err := tc.f(k); !reflect.DeepEqual(err, tc.wantErr) {
 				t.Errorf("%s: error = %v, want %v", fname, err, tc.wantErr)
@@ -200,8 +202,8 @@ func checkOpBehaviour(t *testing.T, testCases []opBehaviourTestCase) {
 				t.Helper()
 				t.Parallel()
 
-				k := &kstub{nil, stub.New(t,
-					func(s *stub.Stub[syscallDispatcher]) syscallDispatcher { return &kstub{nil, s} },
+				k := &kstub{nil, nil, stub.New(t,
+					func(s *stub.Stub[syscallDispatcher]) syscallDispatcher { return &kstub{nil, nil, s} },
 					stub.Expect{Calls: slices.Concat(tc.early, []stub.Call{{Name: stub.CallSeparator}}, tc.apply)},
 				)}
 				state := &setupState{Params: tc.params, Msg: k}
@@ -237,8 +239,11 @@ func sliceAddr[S any](s []S) *[]S { return &s }
 
 func newCheckedFile(t *testing.T, name, wantData string, closeErr error) osFile {
 	f := &checkedOsFile{t: t, name: name, want: wantData, closeErr: closeErr}
-	// check happens in Close, and cleanup is not guaranteed to run, so relying on it for sloppy implementations will cause sporadic test results
-	f.cleanup = runtime.AddCleanup(f, func(name string) { f.t.Fatalf("checkedOsFile %s became unreachable without a call to Close", name) }, f.name)
+	// check happens in Close, and cleanup is not guaranteed to run, so relying
+	// on it for sloppy implementations will cause sporadic test results
+	f.cleanup = runtime.AddCleanup(f, func(name string) {
+		panic("checkedOsFile " + name + " became unreachable without a call to Close")
+	}, name)
 	return f
 }
 
@@ -322,12 +327,19 @@ const (
 
 type kstub struct {
 	wait4signal chan struct{}
+	lockNotify  chan struct{}
 	*stub.Stub[syscallDispatcher]
 }
 
 func (k *kstub) new(f func(k syscallDispatcher)) { k.Helper(); k.New(f) }
 
-func (k *kstub) lockOSThread() { k.Helper(); k.Expects("lockOSThread") }
+func (k *kstub) lockOSThread() {
+	k.Helper()
+	expect := k.Expects("lockOSThread")
+	if k.lockNotify != nil && expect.Ret == magicWait4Signal {
+		<-k.lockNotify
+	}
+}
 
 func (k *kstub) setPtracer(pid uintptr) error {
 	k.Helper()
@@ -378,7 +390,7 @@ func (k *kstub) isatty(fd int) bool {
 	return expect.Ret.(bool)
 }
 
-func (k *kstub) receive(key string, e any, fdp *uintptr) (closeFunc func() error, err error) {
+func (k *kstub) receive(key string, e any, fdp *int) (closeFunc func() error, err error) {
 	k.Helper()
 	expect := k.Expects("receive")
 
@@ -396,10 +408,17 @@ func (k *kstub) receive(key string, e any, fdp *uintptr) (closeFunc func() error
 		}
 		return nil
 	}
+
+	// avoid changing test cases
+	var fdpComp *uintptr
+	if fdp != nil {
+		fdpComp = new(uintptr(*fdp))
+	}
+
 	err = expect.Error(
 		stub.CheckArg(k.Stub, "key", key, 0),
 		stub.CheckArgReflect(k.Stub, "e", e, 1),
-		stub.CheckArgReflect(k.Stub, "fdp", fdp, 2))
+		stub.CheckArgReflect(k.Stub, "fdp", fdpComp, 2))
 
 	// 3 is unused so stores params
 	if expect.Args[3] != nil {
@@ -414,7 +433,7 @@ func (k *kstub) receive(key string, e any, fdp *uintptr) (closeFunc func() error
 	if expect.Args[4] != nil {
 		if v, ok := expect.Args[4].(uintptr); ok && v >= 3 {
 			if fdp != nil {
-				*fdp = v
+				*fdp = int(v)
 			}
 		}
 	}
@@ -457,6 +476,8 @@ func (k *kstub) ensureFile(name string, perm, pperm os.FileMode) error {
 		stub.CheckArg(k.Stub, "pperm", pperm, 2))
 }
 
+func (*kstub) mustLoopback(context.Context, message.Msg) { /* noop */ }
+
 func (k *kstub) seccompLoad(rules []std.NativeRule, flags seccomp.ExportFlag) error {
 	k.Helper()
 	return k.Expects("seccompLoad").Error(
@@ -472,6 +493,10 @@ func (k *kstub) notify(c chan<- os.Signal, sig ...os.Signal) {
 		k.FailNow()
 	}
 
+	if k.lockNotify != nil && expect.Ret == magicWait4Signal {
+		defer close(k.lockNotify)
+	}
+
 	// export channel for external instrumentation
 	if chanf, ok := expect.Args[0].(func(c chan<- os.Signal)); ok && chanf != nil {
 		chanf(c)

container/errors.go

@@ -5,9 +5,9 @@ import (
 	"os"
 	"syscall"
 
-	"hakurei.app/container/check"
-	"hakurei.app/container/vfs"
+	"hakurei.app/check"
 	"hakurei.app/message"
+	"hakurei.app/vfs"
 )
 
 // messageFromError returns a printable error message for a supported concrete type.
@@ -18,7 +18,7 @@ func messageFromError(err error) (m string, ok bool) {
 	if m, ok = messagePrefixP[os.PathError]("cannot ", err); ok {
 		return
 	}
-	if m, ok = messagePrefixP[check.AbsoluteError](zeroString, err); ok {
+	if m, ok = messagePrefix[check.AbsoluteError](zeroString, err); ok {
 		return
 	}
 	if m, ok = messagePrefix[OpRepeatError](zeroString, err); ok {
@@ -43,7 +43,8 @@ func messageFromError(err error) (m string, ok bool) {
 }
 
 // messagePrefix checks and prefixes the error message of a non-pointer error.
-// While this is usable for pointer errors, such use should be avoided as nil check is omitted.
+// While this is usable for pointer errors, such use should be avoided as nil
+// check is omitted.
 func messagePrefix[T error](prefix string, err error) (string, bool) {
 	var targetError T
 	if errors.As(err, &targetError) {

container/errors_test.go

@@ -8,9 +8,9 @@ import (
 	"syscall"
 	"testing"
 
-	"hakurei.app/container/check"
-	"hakurei.app/container/stub"
-	"hakurei.app/container/vfs"
+	"hakurei.app/check"
+	"hakurei.app/internal/stub"
+	"hakurei.app/vfs"
 )
 
 func TestMessageFromError(t *testing.T) {
@@ -37,7 +37,7 @@ func TestMessageFromError(t *testing.T) {
 			Err:  stub.UniqueError(0xdeadbeef),
 		}, "cannot mount /sysroot: unique error 3735928559 injected by the test suite", true},
 
-		{"absolute", &check.AbsoluteError{Pathname: "etc/mtab"},
+		{"absolute", check.AbsoluteError("etc/mtab"),
 			`path "etc/mtab" is not absolute`, true},
 
 		{"repeat", OpRepeatError("autoetc"),

container/executable.go

@@ -1,34 +0,0 @@
-package container
-
-import (
-	"fmt"
-	"log"
-	"os"
-	"sync"
-
-	"hakurei.app/message"
-)
-
-var (
-	executable     string
-	executableOnce sync.Once
-)
-
-func copyExecutable(msg message.Msg) {
-	if name, err := os.Executable(); err != nil {
-		m := fmt.Sprintf("cannot read executable path: %v", err)
-		if msg != nil {
-			msg.BeforeExit()
-			msg.GetLogger().Fatal(m)
-		} else {
-			log.Fatal(m)
-		}
-	} else {
-		executable = name
-	}
-}
-
-func MustExecutable(msg message.Msg) string {
-	executableOnce.Do(func() { copyExecutable(msg) })
-	return executable
-}

container/executable_test.go

@@ -1,18 +0,0 @@
-package container_test
-
-import (
-	"os"
-	"testing"
-
-	"hakurei.app/container"
-	"hakurei.app/message"
-)
-
-func TestExecutable(t *testing.T) {
-	t.Parallel()
-	for i := 0; i < 16; i++ {
-		if got := container.MustExecutable(message.New(nil)); got != os.Args[0] {
-			t.Errorf("MustExecutable: %q, want %q", got, os.Args[0])
-		}
-	}
-}

container/init.go

@@ -7,7 +7,8 @@ import (
 	"log"
 	"os"
 	"os/exec"
-	"path"
+	"os/signal"
+	"path/filepath"
 	"slices"
 	"strconv"
 	"sync"
@@ -15,8 +16,10 @@ import (
 	. "syscall"
 	"time"
 
-	"hakurei.app/container/fhs"
 	"hakurei.app/container/seccomp"
+	"hakurei.app/ext"
+	"hakurei.app/fhs"
+	"hakurei.app/internal/params"
 	"hakurei.app/message"
 )
 
@@ -33,12 +36,12 @@ const (
 	- This path is only accessible by init and root:
 	  The container init sets SUID_DUMP_DISABLE and terminates if that fails.
 
-	It should be noted that none of this should become relevant at any point since the resulting
-	intermediate root tmpfs should be effectively anonymous. */
+	It should be noted that none of this should become relevant at any point
+	since the resulting intermediate root tmpfs should be effectively anonymous. */
 	intermediateHostPath = fhs.Proc + "self/fd"
 
-	// setupEnv is the name of the environment variable holding the string representation of
-	// the read end file descriptor of the setup params pipe.
+	// setupEnv is the name of the environment variable holding the string
+	// representation of the read end file descriptor of the setup params pipe.
 	setupEnv = "HAKUREI_SETUP"
 
 	// exitUnexpectedWait4 is the exit code if wait4 returns an unexpected errno.
@@ -59,7 +62,8 @@ type (
 		// late is called right before starting the initial process.
 		late(state *setupState, k syscallDispatcher) error
 
-		// prefix returns a log message prefix, and whether this Op prints no identifying message on its own.
+		// prefix returns a log message prefix, and whether this Op prints no
+		// identifying message on its own.
 		prefix() (string, bool)
 
 		Is(op Op) bool
@@ -71,9 +75,11 @@ type (
 	setupState struct {
 		nonrepeatable uintptr
 
-		// Whether early reaping has concluded. Must only be accessed in the wait4 loop.
+		// Whether early reaping has concluded. Must only be accessed in the
+		// wait4 loop.
 		processConcluded bool
-		// Process to syscall.WaitStatus populated in the wait4 loop. Freed after early reaping concludes.
+		// Process to syscall.WaitStatus populated in the wait4 loop. Freed
+		// after early reaping concludes.
 		process map[int]WaitStatus
 		// Synchronises access to process.
 		processMu sync.RWMutex
@@ -142,40 +148,46 @@ func initEntrypoint(k syscallDispatcher, msg message.Msg) {
 	}
 
 	var (
-		params      initParams
-		closeSetup  func() error
-		setupFd     uintptr
-		offsetSetup int
+		param      initParams
+		closeSetup func() error
+		setupFd    int
 	)
-	if f, err := k.receive(setupEnv, &params, &setupFd); err != nil {
+	if f, err := k.receive(setupEnv, &param, &setupFd); err != nil {
 		if errors.Is(err, EBADF) {
 			k.fatal(msg, "invalid setup descriptor")
 		}
-		if errors.Is(err, ErrReceiveEnv) {
+		if errors.Is(err, params.ErrReceiveEnv) {
 			k.fatal(msg, setupEnv+" not set")
 		}
 
 		k.fatalf(msg, "cannot decode init setup payload: %v", err)
 	} else {
-		if params.Ops == nil {
+		if param.Ops == nil {
 			k.fatal(msg, "invalid setup parameters")
 		}
-		if params.ParentPerm == 0 {
-			params.ParentPerm = 0755
+		if param.ParentPerm == 0 {
+			param.ParentPerm = 0755
 		}
 
-		msg.SwapVerbose(params.Verbose)
+		msg.SwapVerbose(param.Verbose)
 		msg.Verbose("received setup parameters")
 		closeSetup = f
-		offsetSetup = int(setupFd + 1)
+	}
+
+	if !param.HostNet {
+		ctx, cancel := signal.NotifyContext(context.Background(), CancelSignal,
+			os.Interrupt, SIGTERM, SIGQUIT)
+		defer cancel() // for panics
+		k.mustLoopback(ctx, msg)
+		cancel()
 	}
 
 	// write uid/gid map here so parent does not need to set dumpable
-	if err := k.setDumpable(SUID_DUMP_USER); err != nil {
+	if err := k.setDumpable(ext.SUID_DUMP_USER); err != nil {
 		k.fatalf(msg, "cannot set SUID_DUMP_USER: %v", err)
 	}
 	if err := k.writeFile(fhs.Proc+"self/uid_map",
-		append([]byte{}, strconv.Itoa(params.Uid)+" "+strconv.Itoa(params.HostUid)+" 1\n"...),
+		append([]byte{}, strconv.Itoa(param.Uid)+" "+strconv.Itoa(param.HostUid)+" 1\n"...),
 		0); err != nil {
 		k.fatalf(msg, "%v", err)
 	}
@@ -185,17 +197,17 @@ func initEntrypoint(k syscallDispatcher, msg message.Msg) {
 		k.fatalf(msg, "%v", err)
 	}
 	if err := k.writeFile(fhs.Proc+"self/gid_map",
-		append([]byte{}, strconv.Itoa(params.Gid)+" "+strconv.Itoa(params.HostGid)+" 1\n"...),
+		append([]byte{}, strconv.Itoa(param.Gid)+" "+strconv.Itoa(param.HostGid)+" 1\n"...),
 		0); err != nil {
 		k.fatalf(msg, "%v", err)
 	}
-	if err := k.setDumpable(SUID_DUMP_DISABLE); err != nil {
+	if err := k.setDumpable(ext.SUID_DUMP_DISABLE); err != nil {
 		k.fatalf(msg, "cannot set SUID_DUMP_DISABLE: %v", err)
 	}
 
 	oldmask := k.umask(0)
-	if params.Hostname != "" {
-		if err := k.sethostname([]byte(params.Hostname)); err != nil {
+	if param.Hostname != "" {
+		if err := k.sethostname([]byte(param.Hostname)); err != nil {
 			k.fatalf(msg, "cannot set hostname: %v", err)
 		}
 	}
@@ -208,14 +220,15 @@ func initEntrypoint(k syscallDispatcher, msg message.Msg) {
 	}
 
 	ctx, cancel := context.WithCancel(context.Background())
-	state := &setupState{process: make(map[int]WaitStatus), Params: &params.Params, Msg: msg, Context: ctx}
+	state := &setupState{process: make(map[int]WaitStatus), Params: &param.Params, Msg: msg, Context: ctx}
 	defer cancel()
 
 	/* early is called right before pivot_root into intermediate root;
-	this step is mostly for gathering information that would otherwise be difficult to obtain
-	via library functions after pivot_root, and implementations are expected to avoid changing
-	the state of the mount namespace */
-	for i, op := range *params.Ops {
+	this step is mostly for gathering information that would otherwise be
+	difficult to obtain via library functions after pivot_root, and
+	implementations are expected to avoid changing the state of the mount
+	namespace */
+	for i, op := range *param.Ops {
 		if op == nil || !op.Valid() {
 			k.fatalf(msg, "invalid op at index %d", i)
 		}
@@ -254,11 +267,11 @@ func initEntrypoint(k syscallDispatcher, msg message.Msg) {
 		k.fatalf(msg, "cannot enter intermediate root: %v", err)
 	}
 
-	/* apply is called right after pivot_root and entering the new root;
-	this step sets up the container filesystem, and implementations are expected to keep the host root
-	and sysroot mount points intact but otherwise can do whatever they need to;
-	chdir is allowed but discouraged */
-	for i, op := range *params.Ops {
+	/* apply is called right after pivot_root and entering the new root. This
+	step sets up the container filesystem, and implementations are expected to
+	keep the host root and sysroot mount points intact but otherwise can do
+	whatever they need to. Calling chdir is allowed but discouraged. */
+	for i, op := range *param.Ops {
 		// ops already checked during early setup
 		if prefix, ok := op.prefix(); ok {
 			msg.Verbosef("%s %s", prefix, op)
@@ -282,7 +295,7 @@ func initEntrypoint(k syscallDispatcher, msg message.Msg) {
 
 	{
 		var fd int
-		if err := IgnoringEINTR(func() (err error) {
+		if err := ext.IgnoringEINTR(func() (err error) {
 			fd, err = k.open(fhs.Root, O_DIRECTORY|O_RDONLY, 0)
 			return
 		}); err != nil {
@@ -314,7 +327,7 @@ func initEntrypoint(k syscallDispatcher, msg message.Msg) {
 		k.fatalf(msg, "cannot clear the ambient capability set: %v", err)
 	}
 	for i := uintptr(0); i <= lastcap; i++ {
-		if params.Privileged && i == CAP_SYS_ADMIN {
+		if param.Privileged && i == CAP_SYS_ADMIN {
 			continue
 		}
 		if err := k.capBoundingSetDrop(i); err != nil {
@@ -323,7 +336,7 @@ func initEntrypoint(k syscallDispatcher, msg message.Msg) {
 	}
 
 	var keep [2]uint32
-	if params.Privileged {
+	if param.Privileged {
 		keep[capToIndex(CAP_SYS_ADMIN)] |= capToMask(CAP_SYS_ADMIN)
 
 		if err := k.capAmbientRaise(CAP_SYS_ADMIN); err != nil {
@@ -337,13 +350,13 @@ func initEntrypoint(k syscallDispatcher, msg message.Msg) {
 		k.fatalf(msg, "cannot capset: %v", err)
 	}
 
-	if !params.SeccompDisable {
-		rules := params.SeccompRules
+	if !param.SeccompDisable {
+		rules := param.SeccompRules
 		if len(rules) == 0 { // non-empty rules slice always overrides presets
-			msg.Verbosef("resolving presets %#x", params.SeccompPresets)
-			rules = seccomp.Preset(params.SeccompPresets, params.SeccompFlags)
+			msg.Verbosef("resolving presets %#x", param.SeccompPresets)
+			rules = seccomp.Preset(param.SeccompPresets, param.SeccompFlags)
 		}
-		if err := k.seccompLoad(rules, params.SeccompFlags); err != nil {
+		if err := k.seccompLoad(rules, param.SeccompFlags); err != nil {
 			// this also indirectly asserts PR_SET_NO_NEW_PRIVS
 			k.fatalf(msg, "cannot load syscall filter: %v", err)
 		}
@@ -352,10 +365,10 @@ func initEntrypoint(k syscallDispatcher, msg message.Msg) {
 		msg.Verbose("syscall filter not configured")
 	}
 
-	extraFiles := make([]*os.File, params.Count)
+	extraFiles := make([]*os.File, param.Count)
 	for i := range extraFiles {
 		// setup fd is placed before all extra files
-		extraFiles[i] = k.newFile(uintptr(offsetSetup+i), "extra file "+strconv.Itoa(i))
+		extraFiles[i] = k.newFile(uintptr(setupFd+1+i), "extra file "+strconv.Itoa(i))
 	}
 	k.umask(oldmask)
 
@@ -433,7 +446,7 @@ func initEntrypoint(k syscallDispatcher, msg message.Msg) {
 
 	// called right before startup of initial process, all state changes to the
 	// current process is prohibited during late
-	for i, op := range *params.Ops {
+	for i, op := range *param.Ops {
 		// ops already checked during early setup
 		if err := op.late(state, k); err != nil {
 			if m, ok := messageFromError(err); ok {
@@ -454,14 +467,14 @@ func initEntrypoint(k syscallDispatcher, msg message.Msg) {
 		k.fatalf(msg, "cannot close setup pipe: %v", err)
 	}
 
-	cmd := exec.Command(params.Path.String())
+	cmd := exec.Command(param.Path.String())
 	cmd.Stdin, cmd.Stdout, cmd.Stderr = os.Stdin, os.Stdout, os.Stderr
-	cmd.Args = params.Args
-	cmd.Env = params.Env
+	cmd.Args = param.Args
+	cmd.Env = param.Env
 	cmd.ExtraFiles = extraFiles
-	cmd.Dir = params.Dir.String()
+	cmd.Dir = param.Dir.String()
 
-	msg.Verbosef("starting initial process %s", params.Path)
+	msg.Verbosef("starting initial process %s", param.Path)
 	if err := k.start(cmd); err != nil {
 		k.fatalf(msg, "%v", err)
 	}
@@ -479,9 +492,9 @@ func initEntrypoint(k syscallDispatcher, msg message.Msg) {
 	for {
 		select {
 		case s := <-sig:
-			if s == CancelSignal && params.ForwardCancel && cmd.Process != nil {
+			if s == CancelSignal && param.ForwardCancel && cmd.Process != nil {
 				msg.Verbose("forwarding context cancellation")
-				if err := k.signal(cmd, os.Interrupt); err != nil {
+				if err := k.signal(cmd, os.Interrupt); err != nil && !errors.Is(err, os.ErrProcessDone) {
 					k.printf(msg, "cannot forward cancellation: %v", err)
 				}
 				continue
@@ -511,7 +524,7 @@ func initEntrypoint(k syscallDispatcher, msg message.Msg) {
 				cancel()
 
 				// start timeout early
-				go func() { time.Sleep(params.AdoptWaitDelay); close(timeout) }()
+				go func() { time.Sleep(param.AdoptWaitDelay); close(timeout) }()
 
 				// close initial process files; this also keeps them alive
 				for _, f := range extraFiles {
@@ -555,7 +568,7 @@ func TryArgv0(msg message.Msg) {
 		msg = message.New(log.Default())
 	}
 
-	if len(os.Args) > 0 && path.Base(os.Args[0]) == initName {
+	if len(os.Args) > 0 && filepath.Base(os.Args[0]) == initName {
 		Init(msg)
 		msg.BeforeExit()
 		os.Exit(0)

container/init_test.go

@@ -7,10 +7,11 @@ import (
 	"testing"
 	"time"
 
-	"hakurei.app/container/check"
+	"hakurei.app/check"
 	"hakurei.app/container/seccomp"
 	"hakurei.app/container/std"
-	"hakurei.app/container/stub"
+	"hakurei.app/internal/params"
+	"hakurei.app/internal/stub"
 )
 
 func TestInitEntrypoint(t *testing.T) {
@@ -40,7 +41,7 @@ func TestInitEntrypoint(t *testing.T) {
 				call("lockOSThread", stub.ExpectArgs{}, nil, nil),
 				call("getpid", stub.ExpectArgs{}, 1, nil),
 				call("setPtracer", stub.ExpectArgs{uintptr(0)}, nil, nil),
-				call("receive", stub.ExpectArgs{"HAKUREI_SETUP", new(initParams), new(uintptr)}, nil, ErrReceiveEnv),
+				call("receive", stub.ExpectArgs{"HAKUREI_SETUP", new(initParams), new(uintptr)}, nil, params.ErrReceiveEnv),
 				call("fatal", stub.ExpectArgs{[]any{"HAKUREI_SETUP not set"}}, nil, nil),
 			},
 		}, nil},
@@ -1992,7 +1993,7 @@ func TestInitEntrypoint(t *testing.T) {
 
 			/* wait4 */
 			Tracks: []stub.Expect{{Calls: []stub.Call{
-				call("lockOSThread", stub.ExpectArgs{}, nil, nil),
+				call("lockOSThread", stub.ExpectArgs{}, magicWait4Signal, nil),
 
 				// this terminates the goroutine at the call, preventing it from leaking while preserving behaviour
 				call("wait4", stub.ExpectArgs{-1, nil, 0, nil, stub.PanicExit}, 0, syscall.ECHILD),
@@ -2075,7 +2076,7 @@ func TestInitEntrypoint(t *testing.T) {
 				call("fatalf", stub.ExpectArgs{"cannot close setup pipe: %v", []any{stub.UniqueError(10)}}, nil, nil),
 				call("verbosef", stub.ExpectArgs{"starting initial program %s", []any{check.MustAbs("/run/current-system/sw/bin/bash")}}, nil, nil),
 				call("start", stub.ExpectArgs{"/run/current-system/sw/bin/bash", []string{"bash", "-c", "false"}, ([]string)(nil), "/.hakurei/nonexistent"}, &os.Process{Pid: 0xbad}, nil),
-				call("notify", stub.ExpectArgs{func(c chan<- os.Signal) { c <- CancelSignal }, []os.Signal{CancelSignal, os.Interrupt, syscall.SIGTERM, syscall.SIGQUIT}}, nil, nil),
+				call("notify", stub.ExpectArgs{func(c chan<- os.Signal) { c <- CancelSignal }, []os.Signal{CancelSignal, os.Interrupt, syscall.SIGTERM, syscall.SIGQUIT}}, magicWait4Signal, nil),
 				call("verbose", stub.ExpectArgs{[]any{"forwarding context cancellation"}}, nil, nil),
 				// magicWait4Signal as ret causes wait4 stub to unblock
 				call("signal", stub.ExpectArgs{"/run/current-system/sw/bin/bash", []string{"bash", "-c", "false"}, ([]string)(nil), "/.hakurei/nonexistent", os.Interrupt}, magicWait4Signal, stub.UniqueError(9)),
@@ -2090,7 +2091,7 @@ func TestInitEntrypoint(t *testing.T) {
 
 			/* wait4 */
 			Tracks: []stub.Expect{{Calls: []stub.Call{
-				call("lockOSThread", stub.ExpectArgs{}, nil, nil),
+				call("lockOSThread", stub.ExpectArgs{}, magicWait4Signal, nil),
 
 				// magicWait4Signal as args[4] causes this to block until simulated signal is delivered
 				call("wait4", stub.ExpectArgs{-1, syscall.WaitStatus(0xfade01ce), 0, nil, magicWait4Signal}, 0xbad, nil),
@@ -2175,7 +2176,7 @@ func TestInitEntrypoint(t *testing.T) {
 				call("fatalf", stub.ExpectArgs{"cannot close setup pipe: %v", []any{stub.UniqueError(7)}}, nil, nil),
 				call("verbosef", stub.ExpectArgs{"starting initial program %s", []any{check.MustAbs("/run/current-system/sw/bin/bash")}}, nil, nil),
 				call("start", stub.ExpectArgs{"/run/current-system/sw/bin/bash", []string{"bash", "-c", "false"}, ([]string)(nil), "/.hakurei/nonexistent"}, &os.Process{Pid: 0xbad}, nil),
-				call("notify", stub.ExpectArgs{func(c chan<- os.Signal) { c <- syscall.SIGQUIT }, []os.Signal{CancelSignal, os.Interrupt, syscall.SIGTERM, syscall.SIGQUIT}}, nil, nil),
+				call("notify", stub.ExpectArgs{func(c chan<- os.Signal) { c <- syscall.SIGQUIT }, []os.Signal{CancelSignal, os.Interrupt, syscall.SIGTERM, syscall.SIGQUIT}}, magicWait4Signal, nil),
 				call("verbosef", stub.ExpectArgs{"got %s, forwarding to initial process", []any{"quit"}}, nil, nil),
 				// magicWait4Signal as ret causes wait4 stub to unblock
 				call("signal", stub.ExpectArgs{"/run/current-system/sw/bin/bash", []string{"bash", "-c", "false"}, ([]string)(nil), "/.hakurei/nonexistent", syscall.SIGQUIT}, magicWait4Signal, stub.UniqueError(0xfe)),
@@ -2190,7 +2191,7 @@ func TestInitEntrypoint(t *testing.T) {
 
 			/* wait4 */
 			Tracks: []stub.Expect{{Calls: []stub.Call{
-				call("lockOSThread", stub.ExpectArgs{}, nil, nil),
+				call("lockOSThread", stub.ExpectArgs{}, magicWait4Signal, nil),
 
 				// magicWait4Signal as args[4] causes this to block until simulated signal is delivered
 				call("wait4", stub.ExpectArgs{-1, syscall.WaitStatus(0xfade01ce), 0, nil, magicWait4Signal}, 0xbad, nil),
@@ -2275,7 +2276,7 @@ func TestInitEntrypoint(t *testing.T) {
 				call("fatalf", stub.ExpectArgs{"cannot close setup pipe: %v", []any{stub.UniqueError(7)}}, nil, nil),
 				call("verbosef", stub.ExpectArgs{"starting initial program %s", []any{check.MustAbs("/run/current-system/sw/bin/bash")}}, nil, nil),
 				call("start", stub.ExpectArgs{"/run/current-system/sw/bin/bash", []string{"bash", "-c", "false"}, ([]string)(nil), "/.hakurei/nonexistent"}, &os.Process{Pid: 0xbad}, nil),
-				call("notify", stub.ExpectArgs{func(c chan<- os.Signal) { c <- os.Interrupt }, []os.Signal{CancelSignal, os.Interrupt, syscall.SIGTERM, syscall.SIGQUIT}}, nil, nil),
+				call("notify", stub.ExpectArgs{func(c chan<- os.Signal) { c <- os.Interrupt }, []os.Signal{CancelSignal, os.Interrupt, syscall.SIGTERM, syscall.SIGQUIT}}, magicWait4Signal, nil),
 				call("verbosef", stub.ExpectArgs{"got %s", []any{"interrupt"}}, nil, nil),
 				call("beforeExit", stub.ExpectArgs{}, nil, nil),
 				call("exit", stub.ExpectArgs{0}, nil, nil),
@@ -2283,7 +2284,7 @@ func TestInitEntrypoint(t *testing.T) {
 
 			/* wait4 */
 			Tracks: []stub.Expect{{Calls: []stub.Call{
-				call("lockOSThread", stub.ExpectArgs{}, nil, nil),
+				call("lockOSThread", stub.ExpectArgs{}, magicWait4Signal, nil),
 
 				// this terminates the goroutine at the call, preventing it from leaking while preserving behaviour
 				call("wait4", stub.ExpectArgs{-1, nil, 0, nil, stub.PanicExit}, 0, syscall.ECHILD),
@@ -2366,7 +2367,7 @@ func TestInitEntrypoint(t *testing.T) {
 				call("fatalf", stub.ExpectArgs{"cannot close setup pipe: %v", []any{stub.UniqueError(5)}}, nil, nil),
 				call("verbosef", stub.ExpectArgs{"starting initial program %s", []any{check.MustAbs("/run/current-system/sw/bin/bash")}}, nil, nil),
 				call("start", stub.ExpectArgs{"/run/current-system/sw/bin/bash", []string{"bash", "-c", "false"}, ([]string)(nil), "/.hakurei/nonexistent"}, &os.Process{Pid: 0xbad}, nil),
-				call("notify", stub.ExpectArgs{nil, []os.Signal{CancelSignal, os.Interrupt, syscall.SIGTERM, syscall.SIGQUIT}}, nil, nil),
+				call("notify", stub.ExpectArgs{nil, []os.Signal{CancelSignal, os.Interrupt, syscall.SIGTERM, syscall.SIGQUIT}}, magicWait4Signal, nil),
 				call("verbose", stub.ExpectArgs{[]any{os.ErrInvalid.Error()}}, nil, nil),
 				call("verbose", stub.ExpectArgs{[]any{os.ErrInvalid.Error()}}, nil, nil),
 				call("verbosef", stub.ExpectArgs{"initial process exited with signal %s", []any{syscall.Signal(0x4e)}}, nil, nil),
@@ -2377,7 +2378,7 @@ func TestInitEntrypoint(t *testing.T) {
 
 			/* wait4 */
 			Tracks: []stub.Expect{{Calls: []stub.Call{
-				call("lockOSThread", stub.ExpectArgs{}, nil, nil),
+				call("lockOSThread", stub.ExpectArgs{}, magicWait4Signal, nil),
 
 				call("wait4", stub.ExpectArgs{-1, syscall.WaitStatus(0xfade01ce), 0, nil}, 0xbad, nil),
 				// this terminates the goroutine at the call, preventing it from leaking while preserving behaviour
@@ -2461,7 +2462,7 @@ func TestInitEntrypoint(t *testing.T) {
 				call("fatalf", stub.ExpectArgs{"cannot close setup pipe: %v", []any{stub.UniqueError(3)}}, nil, nil),
 				call("verbosef", stub.ExpectArgs{"starting initial program %s", []any{check.MustAbs("/run/current-system/sw/bin/bash")}}, nil, nil),
 				call("start", stub.ExpectArgs{"/run/current-system/sw/bin/bash", []string{"bash", "-c", "false"}, ([]string)(nil), "/.hakurei/nonexistent"}, &os.Process{Pid: 0xbad}, nil),
-				call("notify", stub.ExpectArgs{nil, []os.Signal{CancelSignal, os.Interrupt, syscall.SIGTERM, syscall.SIGQUIT}}, nil, nil),
+				call("notify", stub.ExpectArgs{nil, []os.Signal{CancelSignal, os.Interrupt, syscall.SIGTERM, syscall.SIGQUIT}}, magicWait4Signal, nil),
 				call("verbose", stub.ExpectArgs{[]any{os.ErrInvalid.Error()}}, nil, nil),
 				call("verbose", stub.ExpectArgs{[]any{os.ErrInvalid.Error()}}, nil, nil),
 				call("verbosef", stub.ExpectArgs{"initial process exited with signal %s", []any{syscall.Signal(0x4e)}}, nil, nil),
@@ -2471,7 +2472,7 @@ func TestInitEntrypoint(t *testing.T) {
 
 			/* wait4 */
 			Tracks: []stub.Expect{{Calls: []stub.Call{
-				call("lockOSThread", stub.ExpectArgs{}, nil, nil),
+				call("lockOSThread", stub.ExpectArgs{}, magicWait4Signal, nil),
 
 				call("wait4", stub.ExpectArgs{-1, nil, 0, nil}, 0, syscall.EINTR),
 				call("wait4", stub.ExpectArgs{-1, nil, 0, nil}, 0, syscall.EINTR),
@@ -2599,7 +2600,7 @@ func TestInitEntrypoint(t *testing.T) {
 				call("fatalf", stub.ExpectArgs{"cannot close setup pipe: %v", []any{stub.UniqueError(1)}}, nil, nil),
 				call("verbosef", stub.ExpectArgs{"starting initial program %s", []any{check.MustAbs("/run/current-system/sw/bin/bash")}}, nil, nil),
 				call("start", stub.ExpectArgs{"/run/current-system/sw/bin/bash", []string{"bash", "-c", "false"}, ([]string)(nil), "/.hakurei/nonexistent"}, &os.Process{Pid: 0xbad}, nil),
-				call("notify", stub.ExpectArgs{nil, []os.Signal{CancelSignal, os.Interrupt, syscall.SIGTERM, syscall.SIGQUIT}}, nil, nil),
+				call("notify", stub.ExpectArgs{nil, []os.Signal{CancelSignal, os.Interrupt, syscall.SIGTERM, syscall.SIGQUIT}}, magicWait4Signal, nil),
 				call("verbose", stub.ExpectArgs{[]any{os.ErrInvalid.Error()}}, nil, nil),
 				call("verbose", stub.ExpectArgs{[]any{os.ErrInvalid.Error()}}, nil, nil),
 				call("verbosef", stub.ExpectArgs{"initial process exited with code %d", []any{1}}, nil, nil),
@@ -2609,7 +2610,7 @@ func TestInitEntrypoint(t *testing.T) {
 
 			/* wait4 */
 			Tracks: []stub.Expect{{Calls: []stub.Call{
-				call("lockOSThread", stub.ExpectArgs{}, nil, nil),
+				call("lockOSThread", stub.ExpectArgs{}, magicWait4Signal, nil),
 
 				call("wait4", stub.ExpectArgs{-1, nil, 0, nil}, 0, syscall.EINTR),
 				call("wait4", stub.ExpectArgs{-1, nil, 0, nil}, 0, syscall.EINTR),
@@ -2741,7 +2742,7 @@ func TestInitEntrypoint(t *testing.T) {
 				call("fatalf", stub.ExpectArgs{"cannot close setup pipe: %v", []any{stub.UniqueError(0)}}, nil, nil),
 				call("verbosef", stub.ExpectArgs{"starting initial program %s", []any{check.MustAbs("/bin/zsh")}}, nil, nil),
 				call("start", stub.ExpectArgs{"/bin/zsh", []string{"zsh", "-c", "exec vim"}, []string{"DISPLAY=:0"}, "/.hakurei"}, &os.Process{Pid: 0xcafe}, nil),
-				call("notify", stub.ExpectArgs{nil, []os.Signal{CancelSignal, os.Interrupt, syscall.SIGTERM, syscall.SIGQUIT}}, nil, nil),
+				call("notify", stub.ExpectArgs{nil, []os.Signal{CancelSignal, os.Interrupt, syscall.SIGTERM, syscall.SIGQUIT}}, magicWait4Signal, nil),
 				call("verbose", stub.ExpectArgs{[]any{os.ErrInvalid.Error()}}, nil, nil),
 				call("verbose", stub.ExpectArgs{[]any{os.ErrInvalid.Error()}}, nil, nil),
 				call("verbose", stub.ExpectArgs{[]any{os.ErrInvalid.Error()}}, nil, nil),
@@ -2752,7 +2753,7 @@ func TestInitEntrypoint(t *testing.T) {
 
 			/* wait4 */
 			Tracks: []stub.Expect{{Calls: []stub.Call{
-				call("lockOSThread", stub.ExpectArgs{}, nil, nil),
+				call("lockOSThread", stub.ExpectArgs{}, magicWait4Signal, nil),
 
 				call("wait4", stub.ExpectArgs{-1, nil, 0, nil}, 0, syscall.EINTR),
 				call("wait4", stub.ExpectArgs{-1, nil, 0, nil}, 0, syscall.EINTR),

container/initbind.go

@@ -6,20 +6,22 @@ import (
 	"os"
 	"syscall"
 
-	"hakurei.app/container/check"
+	"hakurei.app/check"
 	"hakurei.app/container/std"
 )
 
 func init() { gob.Register(new(BindMountOp)) }
 
-// Bind appends an [Op] that bind mounts host path [BindMountOp.Source] on container path [BindMountOp.Target].
+// Bind is a helper for appending [BindMountOp] to [Ops].
 func (f *Ops) Bind(source, target *check.Absolute, flags int) *Ops {
 	*f = append(*f, &BindMountOp{nil, source, target, flags})
 	return f
 }
 
-// BindMountOp bind mounts host path Source on container path Target.
-// Note that Flags uses bits declared in this package and should not be set with constants in [syscall].
+// BindMountOp creates a bind mount from host path Source to container path Target.
+//
+// Note that Flags uses bits declared in the [std] package and should not be set
+// with constants in [syscall].
 type BindMountOp struct {
 	sourceFinal, Source, Target *check.Absolute
 

container/initbind_test.go

@@ -6,9 +6,9 @@ import (
 	"syscall"
 	"testing"
 
-	"hakurei.app/container/check"
+	"hakurei.app/check"
 	"hakurei.app/container/std"
-	"hakurei.app/container/stub"
+	"hakurei.app/internal/stub"
 )
 
 func TestBindMountOp(t *testing.T) {

container/initdaemon.go

@@ -12,8 +12,8 @@ import (
 	"syscall"
 	"time"
 
-	"hakurei.app/container/check"
-	"hakurei.app/container/fhs"
+	"hakurei.app/check"
+	"hakurei.app/fhs"
 )
 
 func init() { gob.Register(new(DaemonOp)) }
@@ -24,8 +24,7 @@ const (
 	daemonTimeout = 5 * time.Second
 )
 
-// Daemon appends an [Op] that starts a daemon in the container and blocks until
-// [DaemonOp.Target] appears.
+// Daemon is a helper for appending [DaemonOp] to [Ops].
 func (f *Ops) Daemon(target, path *check.Absolute, args ...string) *Ops {
 	*f = append(*f, &DaemonOp{target, path, args})
 	return f

container/initdaemon_test.go

@@ -4,8 +4,8 @@ import (
 	"os"
 	"testing"
 
-	"hakurei.app/container/check"
-	"hakurei.app/container/stub"
+	"hakurei.app/check"
+	"hakurei.app/internal/stub"
 	"hakurei.app/message"
 )
 

container/initdev.go

@@ -3,11 +3,11 @@ package container
 import (
 	"encoding/gob"
 	"fmt"
-	"path"
+	"path/filepath"
 	. "syscall"
 
-	"hakurei.app/container/check"
-	"hakurei.app/container/fhs"
+	"hakurei.app/check"
+	"hakurei.app/fhs"
 )
 
 func init() { gob.Register(new(MountDevOp)) }
@@ -19,7 +19,9 @@ func (f *Ops) Dev(target *check.Absolute, mqueue bool) *Ops {
 }
 
 // DevWritable appends an [Op] that mounts a writable subset of host /dev.
-// There is usually no good reason to write to /dev, so this should always be followed by a [RemountOp].
+//
+// There is usually no good reason to write to /dev, so this should always be
+// followed by a [RemountOp].
 func (f *Ops) DevWritable(target *check.Absolute, mqueue bool) *Ops {
 	*f = append(*f, &MountDevOp{target, mqueue, true})
 	return f
@@ -44,7 +46,7 @@ func (d *MountDevOp) apply(state *setupState, k syscallDispatcher) error {
 	}
 
 	for _, name := range []string{"null", "zero", "full", "random", "urandom", "tty"} {
-		targetPath := path.Join(target, name)
+		targetPath := filepath.Join(target, name)
 		if err := k.ensureFile(targetPath, 0444, state.ParentPerm); err != nil {
 			return err
 		}
@@ -60,7 +62,7 @@ func (d *MountDevOp) apply(state *setupState, k syscallDispatcher) error {
 	for i, name := range []string{"stdin", "stdout", "stderr"} {
 		if err := k.symlink(
 			fhs.Proc+"self/fd/"+string(rune(i+'0')),
-			path.Join(target, name),
+			filepath.Join(target, name),
 		); err != nil {
 			return err
 		}
@@ -70,13 +72,13 @@ func (d *MountDevOp) apply(state *setupState, k syscallDispatcher) error {
 		{fhs.Proc + "kcore", "core"},
 		{"pts/ptmx", "ptmx"},
 	} {
-		if err := k.symlink(pair[0], path.Join(target, pair[1])); err != nil {
+		if err := k.symlink(pair[0], filepath.Join(target, pair[1])); err != nil {
 			return err
 		}
 	}
 
-	devShmPath := path.Join(target, "shm")
-	devPtsPath := path.Join(target, "pts")
+	devShmPath := filepath.Join(target, "shm")
+	devPtsPath := filepath.Join(target, "pts")
 	for _, name := range []string{devShmPath, devPtsPath} {
 		if err := k.mkdir(name, state.ParentPerm); err != nil {
 			return err
@@ -90,7 +92,7 @@ func (d *MountDevOp) apply(state *setupState, k syscallDispatcher) error {
 
 	if state.RetainSession {
 		if k.isatty(Stdout) {
-			consolePath := path.Join(target, "console")
+			consolePath := filepath.Join(target, "console")
 			if err := k.ensureFile(consolePath, 0444, state.ParentPerm); err != nil {
 				return err
 			}
@@ -108,7 +110,7 @@ func (d *MountDevOp) apply(state *setupState, k syscallDispatcher) error {
 	}
 
 	if d.Mqueue {
-		mqueueTarget := path.Join(target, "mqueue")
+		mqueueTarget := filepath.Join(target, "mqueue")
 		if err := k.mkdir(mqueueTarget, state.ParentPerm); err != nil {
 			return err
 		}

container/initdev_test.go

@@ -4,8 +4,8 @@ import (
 	"os"
 	"testing"
 
-	"hakurei.app/container/check"
-	"hakurei.app/container/stub"
+	"hakurei.app/check"
+	"hakurei.app/internal/stub"
 )
 
 func TestMountDevOp(t *testing.T) {

container/initmkdir.go

@@ -5,12 +5,12 @@ import (
 	"fmt"
 	"os"
 
-	"hakurei.app/container/check"
+	"hakurei.app/check"
 )
 
 func init() { gob.Register(new(MkdirOp)) }
 
-// Mkdir appends an [Op] that creates a directory in the container filesystem.
+// Mkdir is a helper for appending [MkdirOp] to [Ops].
 func (f *Ops) Mkdir(name *check.Absolute, perm os.FileMode) *Ops {
 	*f = append(*f, &MkdirOp{name, perm})
 	return f

container/initmkdir_test.go

@@ -4,8 +4,8 @@ import (
 	"os"
 	"testing"
 
-	"hakurei.app/container/check"
-	"hakurei.app/container/stub"
+	"hakurei.app/check"
+	"hakurei.app/internal/stub"
 )
 
 func TestMkdirOp(t *testing.T) {

container/initoverlay.go

@@ -6,8 +6,8 @@ import (
 	"slices"
 	"strings"
 
-	"hakurei.app/container/check"
-	"hakurei.app/container/fhs"
+	"hakurei.app/check"
+	"hakurei.app/fhs"
 )
 
 const (
@@ -54,8 +54,11 @@ func (e *OverlayArgumentError) Error() string {
 	}
 }
 
-// Overlay appends an [Op] that mounts the overlay pseudo filesystem on [MountOverlayOp.Target].
-func (f *Ops) Overlay(target, state, work *check.Absolute, layers ...*check.Absolute) *Ops {
+// Overlay is a helper for appending [MountOverlayOp] to [Ops].
+func (f *Ops) Overlay(
+	target, state, work *check.Absolute,
+	layers ...*check.Absolute,
+) *Ops {
 	*f = append(*f, &MountOverlayOp{
 		Target: target,
 		Lower:  layers,
@@ -65,13 +68,12 @@ func (f *Ops) Overlay(target, state, work *check.Absolute, layers ...*check.Abso
 	return f
 }
 
-// OverlayEphemeral appends an [Op] that mounts the overlay pseudo filesystem on [MountOverlayOp.Target]
-// with an ephemeral upperdir and workdir.
+// OverlayEphemeral appends a [MountOverlayOp] with an ephemeral upperdir and workdir.
 func (f *Ops) OverlayEphemeral(target *check.Absolute, layers ...*check.Absolute) *Ops {
 	return f.Overlay(target, fhs.AbsRoot, nil, layers...)
 }
 
-// OverlayReadonly appends an [Op] that mounts the overlay pseudo filesystem readonly on [MountOverlayOp.Target]
+// OverlayReadonly appends a readonly [MountOverlayOp].
 func (f *Ops) OverlayReadonly(target *check.Absolute, layers ...*check.Absolute) *Ops {
 	return f.Overlay(target, nil, nil, layers...)
 }
@@ -82,25 +84,34 @@ type MountOverlayOp struct {
 
 	// Any filesystem, does not need to be on a writable filesystem.
 	Lower []*check.Absolute
-	// formatted for [OptionOverlayLowerdir], resolved, prefixed and escaped during early
+	// Formatted for [OptionOverlayLowerdir].
+	//
+	// Resolved, prefixed and escaped during early.
 	lower []string
+
 	// The upperdir is normally on a writable filesystem.
 	//
-	// If Work is nil and Upper holds the special value [fhs.AbsRoot],
-	// an ephemeral upperdir and workdir will be set up.
+	// If Work is nil and Upper holds the special value [fhs.AbsRoot], an
+	// ephemeral upperdir and workdir will be set up.
 	//
-	// If both Work and Upper are nil, upperdir and workdir is omitted and the overlay is mounted readonly.
+	// If both Work and Upper are nil, upperdir and workdir is omitted and the
+	// overlay is mounted readonly.
 	Upper *check.Absolute
-	// formatted for [OptionOverlayUpperdir], resolved, prefixed and escaped during early
+	// Formatted for [OptionOverlayUpperdir].
+	//
+	// Resolved, prefixed and escaped during early.
 	upper string
+
 	// The workdir needs to be an empty directory on the same filesystem as upperdir.
 	Work *check.Absolute
-	// formatted for [OptionOverlayWorkdir], resolved, prefixed and escaped during early
+	// Formatted for [OptionOverlayWorkdir].
+	//
+	// Resolved, prefixed and escaped during early.
 	work string
 
 	ephemeral bool
 
-	// used internally for mounting to the intermediate root
+	// Used internally for mounting to the intermediate root.
 	noPrefix bool
 }
 

container/initoverlay_test.go

@@ -5,8 +5,8 @@ import (
 	"os"
 	"testing"
 
-	"hakurei.app/container/check"
-	"hakurei.app/container/stub"
+	"hakurei.app/check"
+	"hakurei.app/internal/stub"
 )
 
 func TestMountOverlayOp(t *testing.T) {
@@ -312,7 +312,10 @@ func TestMountOverlayOp(t *testing.T) {
 			},
 		}},
 
-		{"ephemeral", new(Ops).OverlayEphemeral(check.MustAbs("/nix/store"), check.MustAbs("/mnt-root/nix/.ro-store")), Ops{
+		{"ephemeral", new(Ops).OverlayEphemeral(
+			check.MustAbs("/nix/store"),
+			check.MustAbs("/mnt-root/nix/.ro-store"),
+		), Ops{
 			&MountOverlayOp{
 				Target: check.MustAbs("/nix/store"),
 				Lower:  []*check.Absolute{check.MustAbs("/mnt-root/nix/.ro-store")},
@@ -320,7 +323,10 @@ func TestMountOverlayOp(t *testing.T) {
 			},
 		}},
 
-		{"readonly", new(Ops).OverlayReadonly(check.MustAbs("/nix/store"), check.MustAbs("/mnt-root/nix/.ro-store")), Ops{
+		{"readonly", new(Ops).OverlayReadonly(
+			check.MustAbs("/nix/store"),
+			check.MustAbs("/mnt-root/nix/.ro-store"),
+		), Ops{
 			&MountOverlayOp{
 				Target: check.MustAbs("/nix/store"),
 				Lower:  []*check.Absolute{check.MustAbs("/mnt-root/nix/.ro-store")},

container/initplace.go

@@ -5,8 +5,8 @@ import (
 	"fmt"
 	"syscall"
 
-	"hakurei.app/container/check"
-	"hakurei.app/container/fhs"
+	"hakurei.app/check"
+	"hakurei.app/fhs"
 )
 
 const (
@@ -16,7 +16,7 @@ const (
 
 func init() { gob.Register(new(TmpfileOp)) }
 
-// Place appends an [Op] that places a file in container path [TmpfileOp.Path] containing [TmpfileOp.Data].
+// Place is a helper for appending [TmpfileOp] to [Ops].
 func (f *Ops) Place(name *check.Absolute, data []byte) *Ops {
 	*f = append(*f, &TmpfileOp{name, data})
 	return f

container/initplace_test.go

@@ -4,8 +4,8 @@ import (
 	"os"
 	"testing"
 
-	"hakurei.app/container/check"
-	"hakurei.app/container/stub"
+	"hakurei.app/check"
+	"hakurei.app/internal/stub"
 )
 
 func TestTmpfileOp(t *testing.T) {
@@ -21,7 +21,7 @@ func TestTmpfileOp(t *testing.T) {
 			Path: samplePath,
 			Data: sampleData,
 		}, nil, nil, []stub.Call{
-			call("createTemp", stub.ExpectArgs{"/", "tmp.*"}, newCheckedFile(t, "tmp.32768", sampleDataString, nil), stub.UniqueError(5)),
+			call("createTemp", stub.ExpectArgs{"/", "tmp.*"}, (*checkedOsFile)(nil), stub.UniqueError(5)),
 		}, stub.UniqueError(5)},
 
 		{"Write", &Params{ParentPerm: 0700}, &TmpfileOp{
@@ -35,14 +35,14 @@ func TestTmpfileOp(t *testing.T) {
 			Path: samplePath,
 			Data: sampleData,
 		}, nil, nil, []stub.Call{
-			call("createTemp", stub.ExpectArgs{"/", "tmp.*"}, newCheckedFile(t, "tmp.32768", sampleDataString, stub.UniqueError(3)), nil),
+			call("createTemp", stub.ExpectArgs{"/", "tmp.*"}, newCheckedFile(t, "tmp.Close", sampleDataString, stub.UniqueError(3)), nil),
 		}, stub.UniqueError(3)},
 
 		{"ensureFile", &Params{ParentPerm: 0700}, &TmpfileOp{
 			Path: samplePath,
 			Data: sampleData,
 		}, nil, nil, []stub.Call{
-			call("createTemp", stub.ExpectArgs{"/", "tmp.*"}, newCheckedFile(t, "tmp.32768", sampleDataString, nil), nil),
+			call("createTemp", stub.ExpectArgs{"/", "tmp.*"}, newCheckedFile(t, "tmp.ensureFile", sampleDataString, nil), nil),
 			call("ensureFile", stub.ExpectArgs{"/sysroot/etc/passwd", os.FileMode(0444), os.FileMode(0700)}, nil, stub.UniqueError(2)),
 		}, stub.UniqueError(2)},
 
@@ -50,29 +50,29 @@ func TestTmpfileOp(t *testing.T) {
 			Path: samplePath,
 			Data: sampleData,
 		}, nil, nil, []stub.Call{
-			call("createTemp", stub.ExpectArgs{"/", "tmp.*"}, newCheckedFile(t, "tmp.32768", sampleDataString, nil), nil),
+			call("createTemp", stub.ExpectArgs{"/", "tmp.*"}, newCheckedFile(t, "tmp.bindMount", sampleDataString, nil), nil),
 			call("ensureFile", stub.ExpectArgs{"/sysroot/etc/passwd", os.FileMode(0444), os.FileMode(0700)}, nil, nil),
-			call("bindMount", stub.ExpectArgs{"tmp.32768", "/sysroot/etc/passwd", uintptr(0x5), false}, nil, stub.UniqueError(1)),
+			call("bindMount", stub.ExpectArgs{"tmp.bindMount", "/sysroot/etc/passwd", uintptr(0x5), false}, nil, stub.UniqueError(1)),
 		}, stub.UniqueError(1)},
 
 		{"remove", &Params{ParentPerm: 0700}, &TmpfileOp{
 			Path: samplePath,
 			Data: sampleData,
 		}, nil, nil, []stub.Call{
-			call("createTemp", stub.ExpectArgs{"/", "tmp.*"}, newCheckedFile(t, "tmp.32768", sampleDataString, nil), nil),
+			call("createTemp", stub.ExpectArgs{"/", "tmp.*"}, newCheckedFile(t, "tmp.remove", sampleDataString, nil), nil),
 			call("ensureFile", stub.ExpectArgs{"/sysroot/etc/passwd", os.FileMode(0444), os.FileMode(0700)}, nil, nil),
-			call("bindMount", stub.ExpectArgs{"tmp.32768", "/sysroot/etc/passwd", uintptr(0x5), false}, nil, nil),
-			call("remove", stub.ExpectArgs{"tmp.32768"}, nil, stub.UniqueError(0)),
+			call("bindMount", stub.ExpectArgs{"tmp.remove", "/sysroot/etc/passwd", uintptr(0x5), false}, nil, nil),
+			call("remove", stub.ExpectArgs{"tmp.remove"}, nil, stub.UniqueError(0)),
 		}, stub.UniqueError(0)},
 
 		{"success", &Params{ParentPerm: 0700}, &TmpfileOp{
 			Path: samplePath,
 			Data: sampleData,
 		}, nil, nil, []stub.Call{
-			call("createTemp", stub.ExpectArgs{"/", "tmp.*"}, newCheckedFile(t, "tmp.32768", sampleDataString, nil), nil),
+			call("createTemp", stub.ExpectArgs{"/", "tmp.*"}, newCheckedFile(t, "tmp.success", sampleDataString, nil), nil),
 			call("ensureFile", stub.ExpectArgs{"/sysroot/etc/passwd", os.FileMode(0444), os.FileMode(0700)}, nil, nil),
-			call("bindMount", stub.ExpectArgs{"tmp.32768", "/sysroot/etc/passwd", uintptr(0x5), false}, nil, nil),
-			call("remove", stub.ExpectArgs{"tmp.32768"}, nil, nil),
+			call("bindMount", stub.ExpectArgs{"tmp.success", "/sysroot/etc/passwd", uintptr(0x5), false}, nil, nil),
+			call("remove", stub.ExpectArgs{"tmp.success"}, nil, nil),
 		}, nil},
 	})
 

container/initproc.go

@@ -5,12 +5,12 @@ import (
 	"fmt"
 	. "syscall"
 
-	"hakurei.app/container/check"
+	"hakurei.app/check"
 )
 
 func init() { gob.Register(new(MountProcOp)) }
 
-// Proc appends an [Op] that mounts a private instance of proc.
+// Proc is a helper for appending [MountProcOp] to [Ops].
 func (f *Ops) Proc(target *check.Absolute) *Ops {
 	*f = append(*f, &MountProcOp{target})
 	return f

container/initproc_test.go

@@ -4,8 +4,8 @@ import (
 	"os"
 	"testing"
 
-	"hakurei.app/container/check"
-	"hakurei.app/container/stub"
+	"hakurei.app/check"
+	"hakurei.app/internal/stub"
 )
 
 func TestMountProcOp(t *testing.T) {

container/initremount.go

@@ -4,12 +4,12 @@ import (
 	"encoding/gob"
 	"fmt"
 
-	"hakurei.app/container/check"
+	"hakurei.app/check"
 )
 
 func init() { gob.Register(new(RemountOp)) }
 
-// Remount appends an [Op] that applies [RemountOp.Flags] on container path [RemountOp.Target].
+// Remount is a helper for appending [RemountOp] to [Ops].
 func (f *Ops) Remount(target *check.Absolute, flags uintptr) *Ops {
 	*f = append(*f, &RemountOp{target, flags})
 	return f

container/initremount_test.go

@@ -4,8 +4,8 @@ import (
 	"syscall"
 	"testing"
 
-	"hakurei.app/container/check"
-	"hakurei.app/container/stub"
+	"hakurei.app/check"
+	"hakurei.app/internal/stub"
 )
 
 func TestRemountOp(t *testing.T) {

container/initsymlink.go

@@ -3,9 +3,9 @@ package container
 import (
 	"encoding/gob"
 	"fmt"
-	"path"
+	"path/filepath"
 
-	"hakurei.app/container/check"
+	"hakurei.app/check"
 )
 
 func init() { gob.Register(new(SymlinkOp)) }
@@ -30,8 +30,8 @@ func (l *SymlinkOp) Valid() bool { return l != nil && l.Target != nil && l.LinkN
 
 func (l *SymlinkOp) early(_ *setupState, k syscallDispatcher) error {
 	if l.Dereference {
-		if !path.IsAbs(l.LinkName) {
-			return &check.AbsoluteError{Pathname: l.LinkName}
+		if !filepath.IsAbs(l.LinkName) {
+			return check.AbsoluteError(l.LinkName)
 		}
 		if name, err := k.readlink(l.LinkName); err != nil {
 			return err
@@ -44,7 +44,7 @@ func (l *SymlinkOp) early(_ *setupState, k syscallDispatcher) error {
 
 func (l *SymlinkOp) apply(state *setupState, k syscallDispatcher) error {
 	target := toSysroot(l.Target.String())
-	if err := k.mkdirAll(path.Dir(target), state.ParentPerm); err != nil {
+	if err := k.mkdirAll(filepath.Dir(target), state.ParentPerm); err != nil {
 		return err
 	}
 	return k.symlink(l.LinkName, target)

container/initsymlink_test.go

@@ -4,8 +4,8 @@ import (
 	"os"
 	"testing"
 
-	"hakurei.app/container/check"
-	"hakurei.app/container/stub"
+	"hakurei.app/check"
+	"hakurei.app/internal/stub"
 )
 
 func TestSymlinkOp(t *testing.T) {
@@ -23,7 +23,7 @@ func TestSymlinkOp(t *testing.T) {
 			Target:      check.MustAbs("/etc/mtab"),
 			LinkName:    "etc/mtab",
 			Dereference: true,
-		}, nil, &check.AbsoluteError{Pathname: "etc/mtab"}, nil, nil},
+		}, nil, check.AbsoluteError("etc/mtab"), nil, nil},
 
 		{"readlink", &Params{ParentPerm: 0755}, &SymlinkOp{
 			Target:      check.MustAbs("/etc/mtab"),

container/inittmpfs.go

@@ -8,7 +8,7 @@ import (
 	"strconv"
 	. "syscall"
 
-	"hakurei.app/container/check"
+	"hakurei.app/check"
 )
 
 func init() { gob.Register(new(MountTmpfsOp)) }

container/inittmpfs_test.go

@@ -5,8 +5,8 @@ import (
 	"syscall"
 	"testing"
 
-	"hakurei.app/container/check"
-	"hakurei.app/container/stub"
+	"hakurei.app/check"
+	"hakurei.app/internal/stub"
 )
 
 func TestMountTmpfsOp(t *testing.T) {

container/landlock.go

@@ -5,7 +5,7 @@ import (
 	"syscall"
 	"unsafe"
 
-	"hakurei.app/container/std"
+	"hakurei.app/ext"
 )
 
 // include/uapi/linux/landlock.h
@@ -38,6 +38,7 @@ const (
 	_LANDLOCK_ACCESS_FS_DELIM
 )
 
+// String returns a space-separated string of [LandlockAccessFS] flags.
 func (f LandlockAccessFS) String() string {
 	switch f {
 	case LANDLOCK_ACCESS_FS_EXECUTE:
@@ -116,6 +117,7 @@ const (
 	_LANDLOCK_ACCESS_NET_DELIM
 )
 
+// String returns a space-separated string of [LandlockAccessNet] flags.
 func (f LandlockAccessNet) String() string {
 	switch f {
 	case LANDLOCK_ACCESS_NET_BIND_TCP:
@@ -152,6 +154,7 @@ const (
 	_LANDLOCK_SCOPE_DELIM
 )
 
+// String returns a space-separated string of [LandlockScope] flags.
 func (f LandlockScope) String() string {
 	switch f {
 	case LANDLOCK_SCOPE_ABSTRACT_UNIX_SOCKET:
@@ -184,10 +187,12 @@ type RulesetAttr struct {
 	HandledAccessFS LandlockAccessFS
 	// Bitmask of handled network actions.
 	HandledAccessNet LandlockAccessNet
-	// Bitmask of scopes restricting a Landlock domain from accessing outside resources (e.g. IPCs).
+	// Bitmask of scopes restricting a Landlock domain from accessing outside
+	// resources (e.g. IPCs).
 	Scoped LandlockScope
 }
 
+// String returns a user-facing description of [RulesetAttr].
 func (rulesetAttr *RulesetAttr) String() string {
 	if rulesetAttr == nil {
 		return "NULL"
@@ -208,6 +213,7 @@ func (rulesetAttr *RulesetAttr) String() string {
 	return strings.Join(elems, ", ")
 }
 
+// Create loads the ruleset into the kernel.
 func (rulesetAttr *RulesetAttr) Create(flags uintptr) (fd int, err error) {
 	var pointer, size uintptr
 	// NULL needed for abi version
@@ -216,10 +222,13 @@ func (rulesetAttr *RulesetAttr) Create(flags uintptr) (fd int, err error) {
 		size = unsafe.Sizeof(*rulesetAttr)
 	}
 
-	rulesetFd, _, errno := syscall.Syscall(std.SYS_LANDLOCK_CREATE_RULESET, pointer, size, flags)
+	rulesetFd, _, errno := syscall.Syscall(
+		ext.SYS_LANDLOCK_CREATE_RULESET,
+		pointer, size,
+		flags,
+	)
 	fd = int(rulesetFd)
 	err = errno
-
 	if fd < 0 {
 		return
 	}
@@ -230,12 +239,19 @@ func (rulesetAttr *RulesetAttr) Create(flags uintptr) (fd int, err error) {
 	return fd, nil
 }
 
+// LandlockGetABI returns the ABI version supported by the kernel.
 func LandlockGetABI() (int, error) {
 	return (*RulesetAttr)(nil).Create(LANDLOCK_CREATE_RULESET_VERSION)
 }
 
+// LandlockRestrictSelf applies a loaded ruleset to the calling thread.
 func LandlockRestrictSelf(rulesetFd int, flags uintptr) error {
-	r, _, errno := syscall.Syscall(std.SYS_LANDLOCK_RESTRICT_SELF, uintptr(rulesetFd), flags, 0)
+	r, _, errno := syscall.Syscall(
+		ext.SYS_LANDLOCK_RESTRICT_SELF,
+		uintptr(rulesetFd),
+		flags,
+		0,
+	)
 	if r != 0 {
 		return errno
 	}

container/mount.go

@@ -6,8 +6,9 @@ import (
 	"os"
 	. "syscall"
 
-	"hakurei.app/container/vfs"
+	"hakurei.app/ext"
 	"hakurei.app/message"
+	"hakurei.app/vfs"
 )
 
 /*
@@ -115,7 +116,7 @@ func (p *procPaths) remount(msg message.Msg, target string, flags uintptr) error
 	var targetKFinal string
 	{
 		var destFd int
-		if err := IgnoringEINTR(func() (err error) {
+		if err := ext.IgnoringEINTR(func() (err error) {
 			destFd, err = p.k.open(targetFinal, O_PATH|O_CLOEXEC, 0)
 			return
 		}); err != nil {

container/mount_test.go

@@ -5,8 +5,8 @@ import (
 	"syscall"
 	"testing"
 
-	"hakurei.app/container/stub"
-	"hakurei.app/container/vfs"
+	"hakurei.app/internal/stub"
+	"hakurei.app/vfs"
 )
 
 func TestBindMount(t *testing.T) {

container/params.go

@@ -1,47 +0,0 @@
-package container
-
-import (
-	"encoding/gob"
-	"errors"
-	"os"
-	"strconv"
-	"syscall"
-)
-
-// Setup appends the read end of a pipe for setup params transmission and returns its fd.
-func Setup(extraFiles *[]*os.File) (int, *os.File, error) {
-	if r, w, err := os.Pipe(); err != nil {
-		return -1, nil, err
-	} else {
-		fd := 3 + len(*extraFiles)
-		*extraFiles = append(*extraFiles, r)
-		return fd, w, nil
-	}
-}
-
-var (
-	ErrReceiveEnv = errors.New("environment variable not set")
-)
-
-// Receive retrieves setup fd from the environment and receives params.
-func Receive(key string, e any, fdp *uintptr) (func() error, error) {
-	var setup *os.File
-
-	if s, ok := os.LookupEnv(key); !ok {
-		return nil, ErrReceiveEnv
-	} else {
-		if fd, err := strconv.Atoi(s); err != nil {
-			return nil, optionalErrorUnwrap(err)
-		} else {
-			setup = os.NewFile(uintptr(fd), "setup")
-			if setup == nil {
-				return nil, syscall.EDOM
-			}
-			if fdp != nil {
-				*fdp = setup.Fd()
-			}
-		}
-	}
-
-	return setup.Close, gob.NewDecoder(setup).Decode(e)
-}

container/path.go

@@ -4,18 +4,21 @@ import (
 	"errors"
 	"io/fs"
 	"os"
-	"path"
+	"path/filepath"
 	"strconv"
 	"strings"
 	"syscall"
 
-	"hakurei.app/container/fhs"
-	"hakurei.app/container/vfs"
+	"hakurei.app/fhs"
+	"hakurei.app/vfs"
 )
 
 const (
 	// Nonexistent is a path that cannot exist.
-	// /proc is chosen because a system with covered /proc is unsupported by this package.
+	//
+	// This path can never be presented by the kernel if proc is mounted on
+	// /proc/. This can only exist if parts of /proc/ is covered, or proc is not
+	// mounted at all. Neither configuration is supported by this package.
 	Nonexistent = fhs.Proc + "nonexistent"
 
 	hostPath    = fhs.Root + hostDir
@@ -26,16 +29,16 @@ const (
 
 func toSysroot(name string) string {
 	name = strings.TrimLeftFunc(name, func(r rune) bool { return r == '/' })
-	return path.Join(sysrootPath, name)
+	return filepath.Join(sysrootPath, name)
 }
 
 func toHost(name string) string {
 	name = strings.TrimLeftFunc(name, func(r rune) bool { return r == '/' })
-	return path.Join(hostPath, name)
+	return filepath.Join(hostPath, name)
 }
 
 func createFile(name string, perm, pperm os.FileMode, content []byte) error {
-	if err := os.MkdirAll(path.Dir(name), pperm); err != nil {
+	if err := os.MkdirAll(filepath.Dir(name), pperm); err != nil {
 		return err
 	}
 	f, err := os.OpenFile(name, syscall.O_CREAT|syscall.O_EXCL|syscall.O_WRONLY, perm)

container/path_test.go

@@ -4,14 +4,14 @@ import (
 	"io"
 	"math"
 	"os"
-	"path"
+	"path/filepath"
 	"reflect"
 	"syscall"
 	"testing"
 	"unsafe"
 
-	"hakurei.app/container/check"
-	"hakurei.app/container/vfs"
+	"hakurei.app/check"
+	"hakurei.app/vfs"
 )
 
 func TestToSysroot(t *testing.T) {
@@ -61,7 +61,7 @@ func TestCreateFile(t *testing.T) {
 				Path: "/proc/nonexistent",
 				Err:  syscall.ENOENT,
 			}
-			if err := createFile(path.Join(Nonexistent, ":3"), 0644, 0755, nil); !reflect.DeepEqual(err, wantErr) {
+			if err := createFile(filepath.Join(Nonexistent, ":3"), 0644, 0755, nil); !reflect.DeepEqual(err, wantErr) {
 				t.Errorf("createFile: error = %#v, want %#v", err, wantErr)
 			}
 		})
@@ -72,7 +72,7 @@ func TestCreateFile(t *testing.T) {
 				Path: "/proc/nonexistent",
 				Err:  syscall.ENOENT,
 			}
-			if err := createFile(path.Join(Nonexistent), 0644, 0755, nil); !reflect.DeepEqual(err, wantErr) {
+			if err := createFile(filepath.Join(Nonexistent), 0644, 0755, nil); !reflect.DeepEqual(err, wantErr) {
 				t.Errorf("createFile: error = %#v, want %#v", err, wantErr)
 			}
 		})
@@ -80,7 +80,7 @@ func TestCreateFile(t *testing.T) {
 
 	t.Run("touch", func(t *testing.T) {
 		tempDir := t.TempDir()
-		pathname := path.Join(tempDir, "empty")
+		pathname := filepath.Join(tempDir, "empty")
 		if err := createFile(pathname, 0644, 0755, nil); err != nil {
 			t.Fatalf("createFile: error = %v", err)
 		}
@@ -93,7 +93,7 @@ func TestCreateFile(t *testing.T) {
 
 	t.Run("write", func(t *testing.T) {
 		tempDir := t.TempDir()
-		pathname := path.Join(tempDir, "zero")
+		pathname := filepath.Join(tempDir, "zero")
 		if err := createFile(pathname, 0644, 0755, []byte{0}); err != nil {
 			t.Fatalf("createFile: error = %v", err)
 		}
@@ -107,7 +107,7 @@ func TestCreateFile(t *testing.T) {
 
 func TestEnsureFile(t *testing.T) {
 	t.Run("create", func(t *testing.T) {
-		if err := ensureFile(path.Join(t.TempDir(), "ensure"), 0644, 0755); err != nil {
+		if err := ensureFile(filepath.Join(t.TempDir(), "ensure"), 0644, 0755); err != nil {
 			t.Errorf("ensureFile: error = %v", err)
 		}
 	})
@@ -115,7 +115,7 @@ func TestEnsureFile(t *testing.T) {
 	t.Run("stat", func(t *testing.T) {
 		t.Run("inaccessible", func(t *testing.T) {
 			tempDir := t.TempDir()
-			pathname := path.Join(tempDir, "inaccessible")
+			pathname := filepath.Join(tempDir, "inaccessible")
 			if f, err := os.Create(pathname); err != nil {
 				t.Fatalf("Create: error = %v", err)
 			} else {
@@ -150,7 +150,7 @@ func TestEnsureFile(t *testing.T) {
 
 		t.Run("ensure", func(t *testing.T) {
 			tempDir := t.TempDir()
-			pathname := path.Join(tempDir, "ensure")
+			pathname := filepath.Join(tempDir, "ensure")
 			if f, err := os.Create(pathname); err != nil {
 				t.Fatalf("Create: error = %v", err)
 			} else {
@@ -195,12 +195,12 @@ func TestProcPaths(t *testing.T) {
 
 		t.Run("sample", func(t *testing.T) {
 			tempDir := t.TempDir()
-			if err := os.MkdirAll(path.Join(tempDir, "proc/self"), 0755); err != nil {
+			if err := os.MkdirAll(filepath.Join(tempDir, "proc/self"), 0755); err != nil {
 				t.Fatalf("MkdirAll: error = %v", err)
 			}
 
 			t.Run("clean", func(t *testing.T) {
-				if err := os.WriteFile(path.Join(tempDir, "proc/self/mountinfo"), []byte(`15 20 0:3 / /proc rw,relatime - proc /proc rw
+				if err := os.WriteFile(filepath.Join(tempDir, "proc/self/mountinfo"), []byte(`15 20 0:3 / /proc rw,relatime - proc /proc rw
 16 20 0:15 / /sys rw,relatime - sysfs /sys rw
 17 20 0:5 / /dev rw,relatime - devtmpfs udev rw,size=1983516k,nr_inodes=495879,mode=755`), 0644); err != nil {
 					t.Fatalf("WriteFile: error = %v", err)
@@ -243,8 +243,8 @@ func TestProcPaths(t *testing.T) {
 			})
 
 			t.Run("malformed", func(t *testing.T) {
-				path.Join(tempDir, "proc/self/mountinfo")
-				if err := os.WriteFile(path.Join(tempDir, "proc/self/mountinfo"), []byte{0}, 0644); err != nil {
+				filepath.Join(tempDir, "proc/self/mountinfo")
+				if err := os.WriteFile(filepath.Join(tempDir, "proc/self/mountinfo"), []byte{0}, 0644); err != nil {
 					t.Fatalf("WriteFile: error = %v", err)
 				}
 

container/seccomp/libseccomp.go

@@ -16,6 +16,7 @@ import (
 	"unsafe"
 
 	"hakurei.app/container/std"
+	"hakurei.app/ext"
 )
 
 // ErrInvalidRules is returned for a zero-length rules slice.
@@ -88,18 +89,22 @@ var resPrefix = [...]string{
 	7: "seccomp_load failed",
 }
 
-// cbAllocateBuffer is the function signature for the function handle passed to hakurei_export_filter
-// which allocates the buffer that the resulting bpf program is copied into, and writes its slice header
-// to a value held by the caller.
+// cbAllocateBuffer is the function signature for the function handle passed to
+// hakurei_scmp_make_filter which allocates the buffer that the resulting bpf
+// program is copied into, and writes its slice header to a value held by the caller.
 type cbAllocateBuffer = func(len C.size_t) (buf unsafe.Pointer)
 
+// hakurei_scmp_allocate allocates a buffer of specified size known to the
+// runtime through a callback passed in a [cgo.Handle].
+//
 //export hakurei_scmp_allocate
 func hakurei_scmp_allocate(f C.uintptr_t, len C.size_t) (buf unsafe.Pointer) {
 	return cgo.Handle(f).Value().(cbAllocateBuffer)(len)
 }
 
-// makeFilter generates a bpf program from a slice of [std.NativeRule] and writes the resulting byte slice to p.
-// The filter is installed to the current process if p is nil.
+// makeFilter generates a bpf program from a slice of [std.NativeRule] and
+// writes the resulting byte slice to p. The filter is installed to the current
+// process if p is nil.
 func makeFilter(rules []std.NativeRule, flags ExportFlag, p *[]byte) error {
 	if len(rules) == 0 {
 		return ErrInvalidRules
@@ -170,8 +175,8 @@ func Export(rules []std.NativeRule, flags ExportFlag) (data []byte, err error) {
 	return
 }
 
-// Load generates a bpf program from a slice of [std.NativeRule] and enforces it on the current process.
-// Errors returned by libseccomp is wrapped in [LibraryError].
+// Load generates a bpf program from a slice of [std.NativeRule] and enforces it
+// on the current process. Errors returned by libseccomp is wrapped in [LibraryError].
 func Load(rules []std.NativeRule, flags ExportFlag) error { return makeFilter(rules, flags, nil) }
 
 type (
@@ -215,9 +220,9 @@ const (
 
 // syscallResolveName resolves a syscall number by name via seccomp_syscall_resolve_name.
 // This function is only for testing the lookup tables and included here for convenience.
-func syscallResolveName(s string) (num std.ScmpSyscall, ok bool) {
+func syscallResolveName(s string) (num ext.SyscallNum, ok bool) {
 	v := C.CString(s)
-	num = std.ScmpSyscall(C.seccomp_syscall_resolve_name(v))
+	num = ext.SyscallNum(C.seccomp_syscall_resolve_name(v))
 	C.free(unsafe.Pointer(v))
 	ok = num != C.__NR_SCMP_ERROR
 	return

container/seccomp/presets.go

@@ -6,6 +6,7 @@ import (
 	. "syscall"
 
 	. "hakurei.app/container/std"
+	. "hakurei.app/ext"
 )
 
 func Preset(presets FilterPreset, flags ExportFlag) (rules []NativeRule) {

container/seccomp/presets_riscv64_test.go

@@ -0,0 +1,27 @@
+package seccomp_test
+
+import (
+	. "hakurei.app/container/seccomp"
+	. "hakurei.app/container/std"
+)
+
+var bpfExpected = bpfLookup{
+	{AllowMultiarch | AllowCAN |
+		AllowBluetooth, PresetExt |
+		PresetDenyNS | PresetDenyTTY | PresetDenyDevel |
+		PresetLinux32}: toHash(
+		"a1c4ffa35f4bfbf38061184760b9a09edfcb4964c3b534395e47327b83f3fb61f2f9573ddfcc4772424cc2f5dd12fd32471e6531dbe10e85eda3797dd4fa179f"),
+
+	{0, 0}: toHash(
+		"f3910fd727d087def593e3876c2c6ab9ace71d82ec8cbc992a26223e7bba85e1d7a0b56c5fc6303703f24595825dad8561637edaedd5384b34a6cd080946633c"),
+	{0, PresetExt}: toHash(
+		"741438c5e3f11c36c92ae8c5934f13440675c6e719541c2dbffeda79a10081bcfd9ad8314a60c1d1f53db86c8080c13fffa3bbcf7fe753935679b4b902737286"),
+	{0, PresetStrict}: toHash(
+		"79e9e464d02405c6d74fd2c771bd72a1311e488221c73a9c32db9270219837c54fccec2f36fe2474895547e60c311514567e2e6cf4e7a7fcf909c1ecd1e254a7"),
+	{0, PresetDenyNS | PresetDenyTTY | PresetDenyDevel}: toHash(
+		"3c443715a6c1e557a284862ea8efb70a5d4ecbe67d1226627323e861cd3646fb3e7768ec5b94b93760b7f652cf6916f66e317a4fbf8716d10c3673aa4fc3ae58"),
+	{0, PresetExt | PresetDenyDevel}: toHash(
+		"4448a74e8cc75a4ab63799c4f2cc2a5af63e5f4e8e9b8ac15a1873d647dfa67a4c67b39ed466d8dd32abc64136d401879fc6185c9ab00feeaf59ccf4305f8201"),
+	{0, PresetExt | PresetDenyNS | PresetDenyDevel}: toHash(
+		"c7c86e793cb7192f5f6c735f372cda27eb43ae1045e587f8eadb64c849520a3280b6570a3d7b601d32cddb38021585a2234db38e506cebfd10aa3d6c75440f17"),
+}

container/seccomp/std_test.go

@@ -6,12 +6,13 @@ import (
 	"unsafe"
 
 	"hakurei.app/container/std"
+	"hakurei.app/ext"
 )
 
 func TestSyscallResolveName(t *testing.T) {
 	t.Parallel()
 
-	for name, want := range std.Syscalls() {
+	for name, want := range ext.Syscalls() {
 		t.Run(name, func(t *testing.T) {
 			t.Parallel()
 
@@ -24,8 +25,10 @@ func TestSyscallResolveName(t *testing.T) {
 }
 
 func TestRuleType(t *testing.T) {
-	assertKind[std.ScmpUint, scmpUint](t)
-	assertKind[std.ScmpInt, scmpInt](t)
+	assertKind[ext.Uint, scmpUint](t)
+	assertOverflow(t, ext.Uint(ext.MaxUint))
+	assertKind[ext.Int, scmpInt](t)
+	assertOverflow(t, ext.Int(ext.MaxInt))
 
 	assertSize[std.NativeRule, syscallRule](t)
 	assertKind[std.ScmpDatum, scmpDatum](t)
@@ -61,3 +64,14 @@ func assertKind[native, equivalent any](t *testing.T) {
 		t.Fatalf("%s: %s, want %s", nativeType.Name(), nativeType.Kind(), equivalentType.Kind())
 	}
 }
+
+// assertOverflow asserts that incrementing m overflows.
+func assertOverflow[T ~int32 | ~uint32](t *testing.T, m T) {
+	t.Helper()
+
+	old := m
+	m++
+	if m > old {
+		t.Fatalf("unexpected value %#x", m)
+	}
+}

container/std/seccomp.go

@@ -1,30 +1,20 @@
 package std
 
-import (
-	"encoding/json"
-	"strconv"
-)
+import "hakurei.app/ext"
 
 type (
-	// ScmpUint is equivalent to C.uint.
-	ScmpUint uint32
-	// ScmpInt is equivalent to C.int.
-	ScmpInt int32
-
-	// ScmpSyscall represents a syscall number passed to libseccomp via [NativeRule.Syscall].
-	ScmpSyscall ScmpInt
 	// ScmpErrno represents an errno value passed to libseccomp via [NativeRule.Errno].
-	ScmpErrno ScmpInt
+	ScmpErrno = ext.Int
 
 	// ScmpCompare is equivalent to enum scmp_compare;
-	ScmpCompare ScmpUint
+	ScmpCompare = ext.Uint
 	// ScmpDatum is equivalent to scmp_datum_t.
-	ScmpDatum uint64
+	ScmpDatum = uint64
 
 	// ScmpArgCmp is equivalent to struct scmp_arg_cmp.
 	ScmpArgCmp struct {
 		// argument number, starting at 0
-		Arg ScmpUint `json:"arg"`
+		Arg ext.Uint `json:"arg"`
 		// the comparison op, e.g. SCMP_CMP_*
 		Op ScmpCompare `json:"op"`
 
@@ -35,42 +25,10 @@ type (
 	// A NativeRule specifies an arch-specific action taken by seccomp under certain conditions.
 	NativeRule struct {
 		// Syscall is the arch-dependent syscall number to act against.
-		Syscall ScmpSyscall `json:"syscall"`
+		Syscall ext.SyscallNum `json:"syscall"`
 		// Errno is the errno value to return when the condition is satisfied.
 		Errno ScmpErrno `json:"errno"`
 		// Arg is the optional struct scmp_arg_cmp passed to libseccomp.
 		Arg *ScmpArgCmp `json:"arg,omitempty"`
 	}
 )
-
-// MarshalJSON resolves the name of [ScmpSyscall] and encodes it as a [json] string.
-// If such a name does not exist, the syscall number is encoded instead.
-func (num *ScmpSyscall) MarshalJSON() ([]byte, error) {
-	n := *num
-	for name, cur := range Syscalls() {
-		if cur == n {
-			return json.Marshal(name)
-		}
-	}
-	return json.Marshal(n)
-}
-
-// SyscallNameError is returned when trying to unmarshal an invalid syscall name into [ScmpSyscall].
-type SyscallNameError string
-
-func (e SyscallNameError) Error() string { return "invalid syscall name " + strconv.Quote(string(e)) }
-
-// UnmarshalJSON looks up the syscall number corresponding to name encoded in data
-// by calling [SyscallResolveName].
-func (num *ScmpSyscall) UnmarshalJSON(data []byte) error {
-	var name string
-	if err := json.Unmarshal(data, &name); err != nil {
-		return err
-	}
-	if n, ok := SyscallResolveName(name); !ok {
-		return SyscallNameError(name)
-	} else {
-		*num = n
-		return nil
-	}
-}

container/std/syscall.go

@@ -1,28 +0,0 @@
-package std
-
-import "iter"
-
-// Syscalls returns an iterator over all wired syscalls.
-func Syscalls() iter.Seq2[string, ScmpSyscall] {
-	return func(yield func(string, ScmpSyscall) bool) {
-		for name, num := range syscallNum {
-			if !yield(name, num) {
-				return
-			}
-		}
-		for name, num := range syscallNumExtra {
-			if !yield(name, num) {
-				return
-			}
-		}
-	}
-}
-
-// SyscallResolveName resolves a syscall number from its string representation.
-func SyscallResolveName(name string) (num ScmpSyscall, ok bool) {
-	if num, ok = syscallNum[name]; ok {
-		return
-	}
-	num, ok = syscallNumExtra[name]
-	return
-}

container/std/syscall_extra_linux_386.go

@@ -1,13 +0,0 @@
-package std
-
-var syscallNumExtra = map[string]ScmpSyscall{
-	"kexec_file_load": SNR_KEXEC_FILE_LOAD,
-	"subpage_prot":    SNR_SUBPAGE_PROT,
-	"switch_endian":   SNR_SWITCH_ENDIAN,
-}
-
-const (
-	SNR_KEXEC_FILE_LOAD ScmpSyscall = __PNR_kexec_file_load
-	SNR_SUBPAGE_PROT    ScmpSyscall = __PNR_subpage_prot
-	SNR_SWITCH_ENDIAN   ScmpSyscall = __PNR_switch_endian
-)

container/std/syscall_extra_linux_amd64.go

@@ -1,41 +0,0 @@
-package std
-
-var syscallNumExtra = map[string]ScmpSyscall{
-	"umount":          SNR_UMOUNT,
-	"subpage_prot":    SNR_SUBPAGE_PROT,
-	"switch_endian":   SNR_SWITCH_ENDIAN,
-	"vm86":            SNR_VM86,
-	"vm86old":         SNR_VM86OLD,
-	"clock_adjtime64": SNR_CLOCK_ADJTIME64,
-	"clock_settime64": SNR_CLOCK_SETTIME64,
-	"chown32":         SNR_CHOWN32,
-	"fchown32":        SNR_FCHOWN32,
-	"lchown32":        SNR_LCHOWN32,
-	"setgid32":        SNR_SETGID32,
-	"setgroups32":     SNR_SETGROUPS32,
-	"setregid32":      SNR_SETREGID32,
-	"setresgid32":     SNR_SETRESGID32,
-	"setresuid32":     SNR_SETRESUID32,
-	"setreuid32":      SNR_SETREUID32,
-	"setuid32":        SNR_SETUID32,
-}
-
-const (
-	SNR_UMOUNT          ScmpSyscall = __PNR_umount
-	SNR_SUBPAGE_PROT    ScmpSyscall = __PNR_subpage_prot
-	SNR_SWITCH_ENDIAN   ScmpSyscall = __PNR_switch_endian
-	SNR_VM86            ScmpSyscall = __PNR_vm86
-	SNR_VM86OLD         ScmpSyscall = __PNR_vm86old
-	SNR_CLOCK_ADJTIME64 ScmpSyscall = __PNR_clock_adjtime64
-	SNR_CLOCK_SETTIME64 ScmpSyscall = __PNR_clock_settime64
-	SNR_CHOWN32         ScmpSyscall = __PNR_chown32
-	SNR_FCHOWN32        ScmpSyscall = __PNR_fchown32
-	SNR_LCHOWN32        ScmpSyscall = __PNR_lchown32
-	SNR_SETGID32        ScmpSyscall = __PNR_setgid32
-	SNR_SETGROUPS32     ScmpSyscall = __PNR_setgroups32
-	SNR_SETREGID32      ScmpSyscall = __PNR_setregid32
-	SNR_SETRESGID32     ScmpSyscall = __PNR_setresgid32
-	SNR_SETRESUID32     ScmpSyscall = __PNR_setresuid32
-	SNR_SETREUID32      ScmpSyscall = __PNR_setreuid32
-	SNR_SETUID32        ScmpSyscall = __PNR_setuid32
-)

container/std/syscall_extra_linux_arm64.go

@@ -1,55 +0,0 @@
-package std
-
-import "syscall"
-
-const (
-	SYS_NEWFSTATAT = syscall.SYS_FSTATAT
-)
-
-var syscallNumExtra = map[string]ScmpSyscall{
-	"uselib":          SNR_USELIB,
-	"clock_adjtime64": SNR_CLOCK_ADJTIME64,
-	"clock_settime64": SNR_CLOCK_SETTIME64,
-	"umount":          SNR_UMOUNT,
-	"chown":           SNR_CHOWN,
-	"chown32":         SNR_CHOWN32,
-	"fchown32":        SNR_FCHOWN32,
-	"lchown":          SNR_LCHOWN,
-	"lchown32":        SNR_LCHOWN32,
-	"setgid32":        SNR_SETGID32,
-	"setgroups32":     SNR_SETGROUPS32,
-	"setregid32":      SNR_SETREGID32,
-	"setresgid32":     SNR_SETRESGID32,
-	"setresuid32":     SNR_SETRESUID32,
-	"setreuid32":      SNR_SETREUID32,
-	"setuid32":        SNR_SETUID32,
-	"modify_ldt":      SNR_MODIFY_LDT,
-	"subpage_prot":    SNR_SUBPAGE_PROT,
-	"switch_endian":   SNR_SWITCH_ENDIAN,
-	"vm86":            SNR_VM86,
-	"vm86old":         SNR_VM86OLD,
-}
-
-const (
-	SNR_USELIB          ScmpSyscall = __PNR_uselib
-	SNR_CLOCK_ADJTIME64 ScmpSyscall = __PNR_clock_adjtime64
-	SNR_CLOCK_SETTIME64 ScmpSyscall = __PNR_clock_settime64
-	SNR_UMOUNT          ScmpSyscall = __PNR_umount
-	SNR_CHOWN           ScmpSyscall = __PNR_chown
-	SNR_CHOWN32         ScmpSyscall = __PNR_chown32
-	SNR_FCHOWN32        ScmpSyscall = __PNR_fchown32
-	SNR_LCHOWN          ScmpSyscall = __PNR_lchown
-	SNR_LCHOWN32        ScmpSyscall = __PNR_lchown32
-	SNR_SETGID32        ScmpSyscall = __PNR_setgid32
-	SNR_SETGROUPS32     ScmpSyscall = __PNR_setgroups32
-	SNR_SETREGID32      ScmpSyscall = __PNR_setregid32
-	SNR_SETRESGID32     ScmpSyscall = __PNR_setresgid32
-	SNR_SETRESUID32     ScmpSyscall = __PNR_setresuid32
-	SNR_SETREUID32      ScmpSyscall = __PNR_setreuid32
-	SNR_SETUID32        ScmpSyscall = __PNR_setuid32
-	SNR_MODIFY_LDT      ScmpSyscall = __PNR_modify_ldt
-	SNR_SUBPAGE_PROT    ScmpSyscall = __PNR_subpage_prot
-	SNR_SWITCH_ENDIAN   ScmpSyscall = __PNR_switch_endian
-	SNR_VM86            ScmpSyscall = __PNR_vm86
-	SNR_VM86OLD         ScmpSyscall = __PNR_vm86old
-)