TODO: actually write tests lol

The summary marker does not appear in the AOM, so setting its alt text
is fruitless.

.gitignore

@@ -1,37 +1,22 @@
-# Binaries for programs and plugins
-*.exe
-*.exe~
-*.dll
-*.so
-*.dylib
-*.pkg
-/hakurei
-
-# Test binary, built with `go test -c`
+# produced by tools and text editors
+*.qcow2
 *.test
-
-# Output of the go coverage tool, specifically when used with LiteIDE
 *.out
-
-# Dependency directories (remove the comment below to include it)
-# vendor/
-
-# Go workspace file
-go.work
-go.work.sum
-
-# env file
-.env
 .idea
 .vscode
 
 # go generate
 /cmd/hakurei/LICENSE
+/cmd/pkgserver/.sass-cache
+/cmd/pkgserver/ui/static/*.js
+/cmd/pkgserver/ui/static/*.css*
+/cmd/pkgserver/ui/static/*.css.map
+/cmd/pkgserver/ui_test/*.js
+/cmd/pkgserver/ui_test/lib/*.js
+/cmd/pkgserver/ui_test/lib/*.css*
+/cmd/pkgserver/ui_test/lib/*.css.map
 /internal/pkg/testdata/testtool
 /internal/rosa/hakurei_current.tar.gz
 
-# release
-/dist/hakurei-*
-
-# interactive nixos vm
-nixos.qcow2
+# cmd/dist default destination
+/dist

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

@@ -5,7 +5,7 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
-	"path"
+	"path/filepath"
 	"slices"
 	"strings"
 	"syscall"
@@ -61,7 +61,7 @@ func (a *Absolute) Is(v *Absolute) bool {
 
 // NewAbs checks pathname and returns a new [Absolute] if pathname is absolute.
 func NewAbs(pathname string) (*Absolute, error) {
-	if !path.IsAbs(pathname) {
+	if !filepath.IsAbs(pathname) {
 		return nil, AbsoluteError(pathname)
 	}
 	return unsafeAbs(pathname), nil
@@ -76,13 +76,13 @@ func MustAbs(pathname string) *Absolute {
 	}
 }
 
-// Append calls [path.Join] with [Absolute] as the first element.
+// Append calls [filepath.Join] with [Absolute] as the first element.
 func (a *Absolute) Append(elem ...string) *Absolute {
-	return unsafeAbs(path.Join(append([]string{a.String()}, elem...)...))
+	return unsafeAbs(filepath.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())) }
+// 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) {
@@ -92,7 +92,7 @@ func (a *Absolute) GobEncode() ([]byte, error) {
 // GobDecode stores data if it represents an absolute pathname.
 func (a *Absolute) GobDecode(data []byte) error {
 	pathname := string(data)
-	if !path.IsAbs(pathname) {
+	if !filepath.IsAbs(pathname) {
 		return AbsoluteError(pathname)
 	}
 	a.pathname = unique.Make(pathname)
@@ -110,7 +110,7 @@ func (a *Absolute) UnmarshalJSON(data []byte) error {
 	if err := json.Unmarshal(data, &pathname); err != nil {
 		return err
 	}
-	if !path.IsAbs(pathname) {
+	if !filepath.IsAbs(pathname) {
 		return AbsoluteError(pathname)
 	}
 	a.pathname = unique.Make(pathname)

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

@@ -1,3 +1,7 @@
+// 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 (

cmd/hakurei/command.go

@@ -2,6 +2,7 @@ package main
 
 import (
 	"context"
+	"errors"
 	"fmt"
 	"io"
 	"log"
@@ -11,7 +12,6 @@ import (
 	"strconv"
 	"sync"
 	"time"
-	_ "unsafe" // for go:linkname
 
 	"hakurei.app/check"
 	"hakurei.app/command"
@@ -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])
@@ -98,7 +103,7 @@ func buildCommand(ctx context.Context, msg message.Msg, early *earlyHardeningErr
 			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)
 			}
@@ -323,7 +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>] [--policy <value>] [--priority <int>] [--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

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"
@@ -17,12 +51,9 @@ import (
 	"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 }
@@ -31,8 +62,8 @@ 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{

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/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

@@ -1,3 +1,15 @@
+// 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 (
@@ -57,11 +69,12 @@ func main() {
 	}()
 
 	var (
-		flagQuiet  bool
-		flagCures  int
-		flagBase   string
-		flagTShift int
-		flagIdle   bool
+		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)
@@ -77,19 +90,15 @@ func main() {
 		} else if base, err = check.NewAbs(flagBase); err != nil {
 			return
 		}
-		if cache, err = pkg.Open(ctx, msg, flagCures, base); err == nil {
-			if flagTShift < 0 {
-				cache.SetThreshold(0)
-			} else if flagTShift > 31 {
-				cache.SetThreshold(1 << 31)
-			} else {
-				cache.SetThreshold(1 << flagTShift)
-			}
-		}
 
+		var flags int
 		if flagIdle {
-			pkg.SetSchedIdle = true
+			flags |= pkg.CSchedIdle
 		}
+		if flagHostAbstract {
+			flags |= pkg.CHostAbstract
+		}
+		cache, err = pkg.Open(ctx, msg, flags, flagCures, base)
 
 		return
 	}).Flag(
@@ -104,14 +113,17 @@ func main() {
 		&flagBase,
 		"d", command.StringFlag("$MBF_CACHE_DIR"),
 		"Directory to store cured artifacts",
-	).Flag(
-		&flagTShift,
-		"tshift", command.IntFlag(-1),
-		"Dependency graph size exponent, to the power of 2",
 	).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",
 	)
 
 	{
@@ -436,6 +448,7 @@ func main() {
 	{
 		var (
 			flagDump   string
+			flagEnter  bool
 			flagExport string
 		)
 		c.NewCommand(
@@ -445,9 +458,13 @@ func main() {
 				if len(args) != 1 {
 					return errors.New("cure requires 1 argument")
 				}
-				if p, ok := rosa.ResolveName(args[0]); !ok {
+				p, ok := rosa.ResolveName(args[0])
+				if !ok {
 					return fmt.Errorf("unknown artifact %q", args[0])
-				} else if flagDump == "" {
+				}
+
+				switch {
+				default:
 					pathname, _, err := cache.Cure(rosa.Std.Load(p))
 					if err != nil {
 						return err
@@ -477,7 +494,8 @@ func main() {
 					}
 
 					return nil
-				} else {
+
+				case flagDump != "":
 					f, err := os.OpenFile(
 						flagDump,
 						os.O_WRONLY|os.O_CREATE|os.O_EXCL,
@@ -493,6 +511,15 @@ func main() {
 					}
 
 					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",
+					)
 				}
 			},
 		).
@@ -505,6 +532,11 @@ func main() {
 				&flagExport,
 				"export", command.StringFlag(""),
 				"Export cured artifact to specified pathname",
+			).
+			Flag(
+				&flagEnter,
+				"enter", command.BoolFlag(false),
+				"Enter cure container with an interactive shell",
 			)
 	}
 
@@ -527,7 +559,7 @@ func main() {
 					}
 					presets[i] = p
 				}
-				root := make(rosa.Collect, 0, 6+len(args))
+				root := make(pkg.Collect, 0, 6+len(args))
 				root = rosa.Std.AppendPresets(root, presets...)
 
 				if flagWithToolchain {
@@ -543,7 +575,7 @@ func main() {
 
 				if _, _, err := cache.Cure(&root); err == nil {
 					return errors.New("unreachable")
-				} else if !errors.Is(err, rosa.Collected{}) {
+				} else if !pkg.IsCollected(err) {
 					return err
 				}
 
@@ -586,6 +618,9 @@ func main() {
 				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 {
@@ -636,13 +671,13 @@ func main() {
 			).
 			Flag(
 				&flagSession,
-				"session", command.BoolFlag(false),
+				"session", command.BoolFlag(true),
 				"Retain session",
 			).
 			Flag(
 				&flagWithToolchain,
 				"with-toolchain", command.BoolFlag(false),
-				"Include the stage3 LLVM toolchain",
+				"Include the stage2 LLVM toolchain",
 			)
 
 	}

cmd/pkgserver/api.go

@@ -0,0 +1,176 @@
+package main
+
+import (
+	"encoding/json"
+	"log"
+	"net/http"
+	"net/url"
+	"path"
+	"strconv"
+	"sync"
+
+	"hakurei.app/internal/info"
+	"hakurei.app/internal/rosa"
+)
+
+// for lazy initialisation of serveInfo
+var (
+	infoPayload struct {
+		// Current package count.
+		Count int `json:"count"`
+		// Hakurei version, set at link time.
+		HakureiVersion string `json:"hakurei_version"`
+	}
+	infoPayloadOnce sync.Once
+)
+
+// handleInfo writes constant system information.
+func handleInfo(w http.ResponseWriter, _ *http.Request) {
+	infoPayloadOnce.Do(func() {
+		infoPayload.Count = int(rosa.PresetUnexportedStart)
+		infoPayload.HakureiVersion = info.Version()
+	})
+	// TODO(mae): cache entire response if no additional fields are planned
+	writeAPIPayload(w, infoPayload)
+}
+
+// newStatusHandler returns a [http.HandlerFunc] that offers status files for
+// viewing or download, if available.
+func (index *packageIndex) newStatusHandler(disposition bool) http.HandlerFunc {
+	return func(w http.ResponseWriter, r *http.Request) {
+		m, ok := index.names[path.Base(r.URL.Path)]
+		if !ok || !m.HasReport {
+			http.NotFound(w, r)
+			return
+		}
+
+		contentType := "text/plain; charset=utf-8"
+		if disposition {
+			contentType = "application/octet-stream"
+
+			// quoting like this is unsound, but okay, because metadata is hardcoded
+			contentDisposition := `attachment; filename="`
+			contentDisposition += m.Name + "-"
+			if m.Version != "" {
+				contentDisposition += m.Version + "-"
+			}
+			contentDisposition += m.ids + `.log"`
+			w.Header().Set("Content-Disposition", contentDisposition)
+		}
+		w.Header().Set("Content-Type", contentType)
+		w.Header().Set("Cache-Control", "no-cache, no-store, must-revalidate")
+		if err := func() (err error) {
+			defer index.handleAccess(&err)()
+			_, err = w.Write(m.status)
+			return
+		}(); err != nil {
+			log.Println(err)
+			http.Error(
+				w, "cannot deliver status, contact maintainers",
+				http.StatusInternalServerError,
+			)
+		}
+	}
+}
+
+// handleGet writes a slice of metadata with specified order.
+func (index *packageIndex) handleGet(w http.ResponseWriter, r *http.Request) {
+	q := r.URL.Query()
+	limit, err := strconv.Atoi(q.Get("limit"))
+	if err != nil || limit > 100 || limit < 1 {
+		http.Error(
+			w, "limit must be an integer between 1 and 100",
+			http.StatusBadRequest,
+		)
+		return
+	}
+	i, err := strconv.Atoi(q.Get("index"))
+	if err != nil || i >= len(index.sorts[0]) || i < 0 {
+		http.Error(
+			w, "index must be an integer between 0 and "+
+				strconv.Itoa(int(rosa.PresetUnexportedStart-1)),
+			http.StatusBadRequest,
+		)
+		return
+	}
+	sort, err := strconv.Atoi(q.Get("sort"))
+	if err != nil || sort >= len(index.sorts) || sort < 0 {
+		http.Error(
+			w, "sort must be an integer between 0 and "+
+				strconv.Itoa(sortOrderEnd),
+			http.StatusBadRequest,
+		)
+		return
+	}
+	values := index.sorts[sort][i:min(i+limit, len(index.sorts[sort]))]
+	writeAPIPayload(w, &struct {
+		Values []*metadata `json:"values"`
+	}{values})
+}
+
+func (index *packageIndex) handleSearch(w http.ResponseWriter, r *http.Request) {
+	q := r.URL.Query()
+	limit, err := strconv.Atoi(q.Get("limit"))
+	if err != nil || limit > 100 || limit < 1 {
+		http.Error(
+			w, "limit must be an integer between 1 and 100",
+			http.StatusBadRequest,
+		)
+		return
+	}
+	i, err := strconv.Atoi(q.Get("index"))
+	if err != nil || i >= len(index.sorts[0]) || i < 0 {
+		http.Error(
+			w, "index must be an integer between 0 and "+
+				strconv.Itoa(int(rosa.PresetUnexportedStart-1)),
+			http.StatusBadRequest,
+		)
+		return
+	}
+	search, err := url.PathUnescape(q.Get("search"))
+	if len(search) > 100 || err != nil {
+		http.Error(
+			w, "search must be a string between 0 and 100 characters long",
+			http.StatusBadRequest,
+		)
+		return
+	}
+	desc := q.Get("desc") == "true"
+	n, res, err := index.performSearchQuery(limit, i, search, desc)
+	if err != nil {
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+	}
+	writeAPIPayload(w, &struct {
+		Count   int            `json:"count"`
+		Results []searchResult `json:"results"`
+	}{n, res})
+}
+
+// apiVersion is the name of the current API revision, as part of the pattern.
+const apiVersion = "v1"
+
+// registerAPI registers API handler functions.
+func (index *packageIndex) registerAPI(mux *http.ServeMux) {
+	mux.HandleFunc("GET /api/"+apiVersion+"/info", handleInfo)
+	mux.HandleFunc("GET /api/"+apiVersion+"/get", index.handleGet)
+	mux.HandleFunc("GET /api/"+apiVersion+"/search", index.handleSearch)
+	mux.HandleFunc("GET /api/"+apiVersion+"/status/", index.newStatusHandler(false))
+	mux.HandleFunc("GET /status/", index.newStatusHandler(true))
+}
+
+// writeAPIPayload sets headers common to API responses and encodes payload as
+// JSON for the response body.
+func writeAPIPayload(w http.ResponseWriter, payload any) {
+	w.Header().Set("Content-Type", "application/json; charset=utf-8")
+	w.Header().Set("Cache-Control", "no-cache, no-store, must-revalidate")
+	w.Header().Set("Pragma", "no-cache")
+	w.Header().Set("Expires", "0")
+
+	if err := json.NewEncoder(w).Encode(payload); err != nil {
+		log.Println(err)
+		http.Error(
+			w, "cannot encode payload, contact maintainers",
+			http.StatusInternalServerError,
+		)
+	}
+}

cmd/pkgserver/api_test.go

@@ -0,0 +1,183 @@
+package main
+
+import (
+	"net/http"
+	"net/http/httptest"
+	"slices"
+	"strconv"
+	"testing"
+
+	"hakurei.app/internal/info"
+	"hakurei.app/internal/rosa"
+)
+
+// prefix is prepended to every API path.
+const prefix = "/api/" + apiVersion + "/"
+
+func TestAPIInfo(t *testing.T) {
+	t.Parallel()
+
+	w := httptest.NewRecorder()
+	handleInfo(w, httptest.NewRequestWithContext(
+		t.Context(),
+		http.MethodGet,
+		prefix+"info",
+		nil,
+	))
+
+	resp := w.Result()
+	checkStatus(t, resp, http.StatusOK)
+	checkAPIHeader(t, w.Header())
+
+	checkPayload(t, resp, struct {
+		Count          int    `json:"count"`
+		HakureiVersion string `json:"hakurei_version"`
+	}{int(rosa.PresetUnexportedStart), info.Version()})
+}
+
+func TestAPIGet(t *testing.T) {
+	t.Parallel()
+	const target = prefix + "get"
+
+	index := newIndex(t)
+	newRequest := func(suffix string) *httptest.ResponseRecorder {
+		w := httptest.NewRecorder()
+		index.handleGet(w, httptest.NewRequestWithContext(
+			t.Context(),
+			http.MethodGet,
+			target+suffix,
+			nil,
+		))
+		return w
+	}
+
+	checkValidate := func(t *testing.T, suffix string, vmin, vmax int, wantErr string) {
+		t.Run("invalid", func(t *testing.T) {
+			t.Parallel()
+
+			w := newRequest("?" + suffix + "=invalid")
+			resp := w.Result()
+			checkError(t, resp, wantErr, http.StatusBadRequest)
+		})
+
+		t.Run("min", func(t *testing.T) {
+			t.Parallel()
+
+			w := newRequest("?" + suffix + "=" + strconv.Itoa(vmin-1))
+			resp := w.Result()
+			checkError(t, resp, wantErr, http.StatusBadRequest)
+
+			w = newRequest("?" + suffix + "=" + strconv.Itoa(vmin))
+			resp = w.Result()
+			checkStatus(t, resp, http.StatusOK)
+		})
+
+		t.Run("max", func(t *testing.T) {
+			t.Parallel()
+
+			w := newRequest("?" + suffix + "=" + strconv.Itoa(vmax+1))
+			resp := w.Result()
+			checkError(t, resp, wantErr, http.StatusBadRequest)
+
+			w = newRequest("?" + suffix + "=" + strconv.Itoa(vmax))
+			resp = w.Result()
+			checkStatus(t, resp, http.StatusOK)
+		})
+	}
+
+	t.Run("limit", func(t *testing.T) {
+		t.Parallel()
+		checkValidate(
+			t, "index=0&sort=0&limit", 1, 100,
+			"limit must be an integer between 1 and 100",
+		)
+	})
+
+	t.Run("index", func(t *testing.T) {
+		t.Parallel()
+		checkValidate(
+			t, "limit=1&sort=0&index", 0, int(rosa.PresetUnexportedStart-1),
+			"index must be an integer between 0 and "+strconv.Itoa(int(rosa.PresetUnexportedStart-1)),
+		)
+	})
+
+	t.Run("sort", func(t *testing.T) {
+		t.Parallel()
+		checkValidate(
+			t, "index=0&limit=1&sort", 0, int(sortOrderEnd),
+			"sort must be an integer between 0 and "+strconv.Itoa(int(sortOrderEnd)),
+		)
+	})
+
+	checkWithSuffix := func(name, suffix string, want []*metadata) {
+		t.Run(name, func(t *testing.T) {
+			t.Parallel()
+
+			w := newRequest(suffix)
+			resp := w.Result()
+			checkStatus(t, resp, http.StatusOK)
+			checkAPIHeader(t, w.Header())
+			checkPayloadFunc(t, resp, func(got *struct {
+				Count  int         `json:"count"`
+				Values []*metadata `json:"values"`
+			}) bool {
+				return got.Count == len(want) &&
+					slices.EqualFunc(got.Values, want, func(a, b *metadata) bool {
+						return (a.Version == b.Version ||
+							a.Version == rosa.Unversioned ||
+							b.Version == rosa.Unversioned) &&
+							a.HasReport == b.HasReport &&
+							a.Name == b.Name &&
+							a.Description == b.Description &&
+							a.Website == b.Website
+					})
+			})
+
+		})
+	}
+
+	checkWithSuffix("declarationAscending", "?limit=2&index=0&sort=0", []*metadata{
+		{
+			Metadata: rosa.GetMetadata(0),
+			Version:  rosa.Std.Version(0),
+		},
+		{
+			Metadata: rosa.GetMetadata(1),
+			Version:  rosa.Std.Version(1),
+		},
+	})
+	checkWithSuffix("declarationAscending offset", "?limit=3&index=5&sort=0", []*metadata{
+		{
+			Metadata: rosa.GetMetadata(5),
+			Version:  rosa.Std.Version(5),
+		},
+		{
+			Metadata: rosa.GetMetadata(6),
+			Version:  rosa.Std.Version(6),
+		},
+		{
+			Metadata: rosa.GetMetadata(7),
+			Version:  rosa.Std.Version(7),
+		},
+	})
+	checkWithSuffix("declarationDescending", "?limit=3&index=0&sort=1", []*metadata{
+		{
+			Metadata: rosa.GetMetadata(rosa.PresetUnexportedStart - 1),
+			Version:  rosa.Std.Version(rosa.PresetUnexportedStart - 1),
+		},
+		{
+			Metadata: rosa.GetMetadata(rosa.PresetUnexportedStart - 2),
+			Version:  rosa.Std.Version(rosa.PresetUnexportedStart - 2),
+		},
+		{
+			Metadata: rosa.GetMetadata(rosa.PresetUnexportedStart - 3),
+			Version:  rosa.Std.Version(rosa.PresetUnexportedStart - 3),
+		},
+	})
+	checkWithSuffix("declarationDescending offset", "?limit=1&index=37&sort=1", []*metadata{
+		{
+			Metadata: rosa.GetMetadata(rosa.PresetUnexportedStart - 38),
+			Version:  rosa.Std.Version(rosa.PresetUnexportedStart - 38),
+		},
+	})
+}

cmd/pkgserver/index.go

@@ -0,0 +1,105 @@
+package main
+
+import (
+	"cmp"
+	"errors"
+	"slices"
+	"strings"
+
+	"hakurei.app/internal/pkg"
+	"hakurei.app/internal/rosa"
+)
+
+const (
+	declarationAscending = iota
+	declarationDescending
+	nameAscending
+	nameDescending
+	sizeAscending
+	sizeDescending
+
+	sortOrderEnd = iota - 1
+)
+
+// packageIndex refers to metadata by name and various sort orders.
+type packageIndex struct {
+	sorts  [sortOrderEnd + 1][rosa.PresetUnexportedStart]*metadata
+	names  map[string]*metadata
+	search searchCache
+	// Taken from [rosa.Report] if available.
+	handleAccess func(*error) func()
+}
+
+// metadata holds [rosa.Metadata] extended with additional information.
+type metadata struct {
+	p rosa.PArtifact
+	*rosa.Metadata
+
+	// Populated via [rosa.Toolchain.Version], [rosa.Unversioned] is equivalent
+	// to the zero value. Otherwise, the zero value is invalid.
+	Version string `json:"version,omitempty"`
+	// Output data size, available if present in report.
+	Size int64 `json:"size,omitempty"`
+	// Whether the underlying [pkg.Artifact] is present in the report.
+	HasReport bool `json:"report"`
+
+	// Ident string encoded ahead of time.
+	ids string
+	// Backed by [rosa.Report], access must be prepared by HandleAccess.
+	status []byte
+}
+
+// populate deterministically populates packageIndex, optionally with a report.
+func (index *packageIndex) populate(cache *pkg.Cache, report *rosa.Report) (err error) {
+	if report != nil {
+		defer report.HandleAccess(&err)()
+		index.handleAccess = report.HandleAccess
+	}
+
+	var work [rosa.PresetUnexportedStart]*metadata
+	index.names = make(map[string]*metadata)
+	for p := range rosa.PresetUnexportedStart {
+		m := metadata{
+			p: p,
+
+			Metadata: rosa.GetMetadata(p),
+			Version:  rosa.Std.Version(p),
+		}
+		if m.Version == "" {
+			return errors.New("invalid version from " + m.Name)
+		}
+		if m.Version == rosa.Unversioned {
+			m.Version = ""
+		}
+
+		if cache != nil && report != nil {
+			id := cache.Ident(rosa.Std.Load(p))
+			m.ids = pkg.Encode(id.Value())
+			m.status, m.Size = report.ArtifactOf(id)
+			m.HasReport = m.Size >= 0
+		}
+
+		work[p] = &m
+		index.names[m.Name] = &m
+	}
+
+	index.sorts[declarationAscending] = work
+	index.sorts[declarationDescending] = work
+	slices.Reverse(index.sorts[declarationDescending][:])
+
+	index.sorts[nameAscending] = work
+	slices.SortFunc(index.sorts[nameAscending][:], func(a, b *metadata) int {
+		return strings.Compare(a.Name, b.Name)
+	})
+	index.sorts[nameDescending] = index.sorts[nameAscending]
+	slices.Reverse(index.sorts[nameDescending][:])
+
+	index.sorts[sizeAscending] = work
+	slices.SortFunc(index.sorts[sizeAscending][:], func(a, b *metadata) int {
+		return cmp.Compare(a.Size, b.Size)
+	})
+	index.sorts[sizeDescending] = index.sorts[sizeAscending]
+	slices.Reverse(index.sorts[sizeDescending][:])
+
+	return
+}

cmd/pkgserver/main.go

@@ -0,0 +1,115 @@
+package main
+
+import (
+	"context"
+	"errors"
+	"log"
+	"net/http"
+	"os"
+	"os/signal"
+	"syscall"
+	"time"
+
+	"hakurei.app/command"
+	"hakurei.app/container/check"
+	"hakurei.app/internal/pkg"
+	"hakurei.app/internal/rosa"
+	"hakurei.app/message"
+)
+
+const shutdownTimeout = 15 * time.Second
+
+func main() {
+	log.SetFlags(0)
+	log.SetPrefix("pkgserver: ")
+
+	var (
+		flagBaseDir string
+		flagAddr    string
+	)
+
+	ctx, stop := signal.NotifyContext(context.Background(), syscall.SIGINT, syscall.SIGTERM, syscall.SIGHUP)
+	defer stop()
+	msg := message.New(log.Default())
+
+	c := command.New(os.Stderr, log.Printf, "pkgserver", func(args []string) error {
+		var (
+			cache  *pkg.Cache
+			report *rosa.Report
+		)
+		switch len(args) {
+		case 0:
+			break
+
+		case 1:
+			baseDir, err := check.NewAbs(flagBaseDir)
+			if err != nil {
+				return err
+			}
+
+			cache, err = pkg.Open(ctx, msg, 0, baseDir)
+			if err != nil {
+				return err
+			}
+			defer cache.Close()
+
+			report, err = rosa.OpenReport(args[0])
+			if err != nil {
+				return err
+			}
+
+		default:
+			return errors.New("pkgserver requires 1 argument")
+
+		}
+
+		var index packageIndex
+		index.search = make(searchCache)
+		if err := index.populate(cache, report); err != nil {
+			return err
+		}
+		ticker := time.NewTicker(1 * time.Minute)
+		go func() {
+			for {
+				select {
+				case <-ctx.Done():
+					ticker.Stop()
+					return
+				case <-ticker.C:
+					index.search.clean()
+				}
+			}
+		}()
+		var mux http.ServeMux
+		uiRoutes(&mux)
+		testUiRoutes(&mux)
+		index.registerAPI(&mux)
+		server := http.Server{
+			Addr:    flagAddr,
+			Handler: &mux,
+		}
+		go func() {
+			<-ctx.Done()
+			c, cancel := context.WithTimeout(context.Background(), shutdownTimeout)
+			defer cancel()
+			if err := server.Shutdown(c); err != nil {
+				log.Fatal(err)
+			}
+		}()
+		return server.ListenAndServe()
+	}).Flag(
+		&flagBaseDir,
+		"b", command.StringFlag(""),
+		"base directory for cache",
+	).Flag(
+		&flagAddr,
+		"addr", command.StringFlag(":8067"),
+		"TCP network address to listen on",
+	)
+	c.MustParse(os.Args[1:], func(err error) {
+		if errors.Is(err, http.ErrServerClosed) {
+			os.Exit(0)
+		}
+		log.Fatal(err)
+	})
+}

cmd/pkgserver/main_test.go

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

cmd/pkgserver/search.go

@@ -0,0 +1,77 @@
+package main
+
+import (
+	"cmp"
+	"maps"
+	"regexp"
+	"slices"
+	"time"
+)
+
+type searchCache map[string]searchCacheEntry
+type searchResult struct {
+	NameIndices [][]int `json:"name_matches"`
+	DescIndices [][]int `json:"desc_matches,omitempty"`
+	Score       float64 `json:"score"`
+	*metadata
+}
+type searchCacheEntry struct {
+	query   string
+	results []searchResult
+	expiry  time.Time
+}
+
+func (index *packageIndex) performSearchQuery(limit int, i int, search string, desc bool) (int, []searchResult, error) {
+	entry, ok := index.search[search]
+	if ok {
+		return len(entry.results), entry.results[i:min(i+limit, len(entry.results))], nil
+	}
+
+	regex, err := regexp.Compile(search)
+	if err != nil {
+		return 0, make([]searchResult, 0), err
+	}
+	res := make([]searchResult, 0)
+	for p := range maps.Values(index.names) {
+		nameIndices := regex.FindAllIndex([]byte(p.Name), -1)
+		var descIndices [][]int = nil
+		if desc {
+			descIndices = regex.FindAllIndex([]byte(p.Description), -1)
+		}
+		if nameIndices == nil && descIndices == nil {
+			continue
+		}
+		score := float64(indexsum(nameIndices)) / (float64(len(nameIndices)) + 1)
+		if desc {
+			score += float64(indexsum(descIndices)) / (float64(len(descIndices)) + 1) / 10.0
+		}
+		res = append(res, searchResult{
+			NameIndices: nameIndices,
+			DescIndices: descIndices,
+			Score:       score,
+			metadata:    p,
+		})
+	}
+	slices.SortFunc(res[:], func(a, b searchResult) int { return -cmp.Compare(a.Score, b.Score) })
+	expiry := time.Now().Add(1 * time.Minute)
+	entry = searchCacheEntry{
+		query:   search,
+		results: res,
+		expiry:  expiry,
+	}
+	index.search[search] = entry
+
+	return len(res), res[i:min(i+limit, len(entry.results))], nil
+}
+func (s *searchCache) clean() {
+	maps.DeleteFunc(*s, func(_ string, v searchCacheEntry) bool {
+		return v.expiry.Before(time.Now())
+	})
+}
+func indexsum(in [][]int) int {
+	sum := 0
+	for i := 0; i < len(in); i++ {
+		sum += in[i][1] - in[i][0]
+	}
+	return sum
+}

cmd/pkgserver/test_ui.go

@@ -0,0 +1,97 @@
+//go:build frontend && frontend_test
+
+package main
+
+import (
+	"embed"
+	"net/http"
+	"path"
+	"strings"
+)
+
+//go:generate tsc -p ui_test
+//go:generate sass ui_test/lib/ui.scss ui_test/lib/ui.css
+//go:embed ui_test/*
+var test_content embed.FS
+
+func serveTestWebUI(w http.ResponseWriter, r *http.Request) {
+	w.Header().Set("X-Content-Type-Options", "nosniff")
+	w.Header().Set("X-XSS-Protection", "1")
+	w.Header().Set("X-Frame-Options", "DENY")
+
+	http.ServeFileFS(w, r, test_content, "ui_test/lib/ui.html")
+}
+
+func serveTestWebUIStaticContent(w http.ResponseWriter, r *http.Request) {
+	switch r.URL.Path {
+	case "/testui/style.css":
+		http.ServeFileFS(w, r, test_content, "ui_test/lib/ui.css")
+	case "/testui/skip-closed.svg":
+		http.ServeFileFS(w, r, test_content, "ui_test/lib/skip-closed.svg")
+	case "/testui/skip-open.svg":
+		http.ServeFileFS(w, r, test_content, "ui_test/lib/skip-open.svg")
+	case "/testui/success-closed.svg":
+		http.ServeFileFS(w, r, test_content, "ui_test/lib/success-closed.svg")
+	case "/testui/success-open.svg":
+		http.ServeFileFS(w, r, test_content, "ui_test/lib/success-open.svg")
+	case "/testui/failure-closed.svg":
+		http.ServeFileFS(w, r, test_content, "ui_test/lib/failure-closed.svg")
+	case "/testui/failure-open.svg":
+		http.ServeFileFS(w, r, test_content, "ui_test/lib/failure-open.svg")
+	default:
+		http.NotFound(w, r)
+	}
+}
+
+func serveTestLibrary(w http.ResponseWriter, r *http.Request) {
+	switch r.URL.Path {
+	case "/test/lib/test.js":
+		http.ServeFileFS(w, r, test_content, "ui_test/lib/test.js")
+	default:
+		http.NotFound(w, r)
+	}
+}
+
+func serveTests(w http.ResponseWriter, r *http.Request) {
+	if r.URL.Path == "/test/" {
+		http.Redirect(w, r, "/test.html", http.StatusMovedPermanently)
+		return
+	}
+	testPath := strings.TrimPrefix(r.URL.Path, "/test/")
+
+	if path.Ext(testPath) != ".js" {
+		http.Error(w, "403 forbidden", http.StatusForbidden)
+	}
+
+	w.Header().Set("Cache-Control", "no-cache, no-store, must-revalidate")
+	w.Header().Set("Pragma", "no-cache")
+	w.Header().Set("Expires", "0")
+
+	http.ServeFileFS(w, r, test_content, "ui_test/"+testPath)
+}
+
+func redirectUI(w http.ResponseWriter, r *http.Request) {
+	// The base path should not redirect to the root.
+	if r.URL.Path == "/ui/" {
+		http.NotFound(w, r)
+		return
+	}
+	if path.Ext(r.URL.Path) != ".js" {
+		http.Error(w, "403 forbidden", http.StatusForbidden)
+		return
+	}
+
+	w.Header().Set("Cache-Control", "no-cache, no-store, must-revalidate")
+	w.Header().Set("Pragma", "no-cache")
+	w.Header().Set("Expires", "0")
+
+	http.Redirect(w, r, strings.TrimPrefix(r.URL.Path, "/ui"), http.StatusFound)
+}
+
+func testUiRoutes(mux *http.ServeMux) {
+	mux.HandleFunc("GET /test.html", serveTestWebUI)
+	mux.HandleFunc("GET /testui/", serveTestWebUIStaticContent)
+	mux.HandleFunc("GET /test/lib", serveTestLibrary)
+	mux.HandleFunc("GET /test/", serveTests)
+	mux.HandleFunc("GET /ui/", redirectUI)
+}

cmd/pkgserver/test_ui_stub.go

@@ -0,0 +1,7 @@
+//go:build !(frontend && frontend_test)
+
+package main
+
+import "net/http"
+
+func testUiRoutes(mux *http.ServeMux) {}

cmd/pkgserver/ui.go

@@ -0,0 +1,38 @@
+package main
+
+import "net/http"
+
+func serveWebUI(w http.ResponseWriter, r *http.Request) {
+	w.Header().Set("Cache-Control", "no-cache, no-store, must-revalidate")
+	w.Header().Set("Pragma", "no-cache")
+	w.Header().Set("Expires", "0")
+	w.Header().Set("X-Content-Type-Options", "nosniff")
+	w.Header().Set("X-XSS-Protection", "1")
+	w.Header().Set("X-Frame-Options", "DENY")
+
+	http.ServeFileFS(w, r, content, "ui/index.html")
+}
+func serveStaticContent(w http.ResponseWriter, r *http.Request) {
+	switch r.URL.Path {
+	case "/static/style.css":
+		darkTheme := r.CookiesNamed("dark_theme")
+		if len(darkTheme) > 0 && darkTheme[0].Value == "true" {
+			http.ServeFileFS(w, r, content, "ui/static/dark.css")
+		} else {
+			http.ServeFileFS(w, r, content, "ui/static/light.css")
+		}
+	case "/favicon.ico":
+		http.ServeFileFS(w, r, content, "ui/static/favicon.ico")
+	case "/static/index.js":
+		http.ServeFileFS(w, r, content, "ui/static/index.js")
+	default:
+		http.NotFound(w, r)
+
+	}
+}
+
+func uiRoutes(mux *http.ServeMux) {
+	mux.HandleFunc("GET /{$}", serveWebUI)
+	mux.HandleFunc("GET /favicon.ico", serveStaticContent)
+	mux.HandleFunc("GET /static/", serveStaticContent)
+}

cmd/pkgserver/ui/index.html

@@ -0,0 +1,35 @@
+<!DOCTYPE html>
+<html lang="en">
+<head>
+    <meta charset="UTF-8">
+    <link rel="stylesheet" href="static/style.css">
+    <title>Hakurei PkgServer</title>
+    <script src="static/index.js"></script>
+</head>
+<body>
+<h1>Hakurei PkgServer</h1>
+
+<table id="pkg-list">
+    <tr><td>Loading...</td></tr>
+</table>
+<p>Showing entries <span id="entry-counter"></span>.</p>
+<span class="bottom-nav"><a href="javascript:prevPage()">&laquo; Previous</a> <span id="page-number">1</span> <a href="javascript:nextPage()">Next &raquo;</a></span>
+<span><label for="count">Entries per page: </label><select name="count" id="count">
+    <option value="10">10</option>
+    <option value="20">20</option>
+    <option value="30">30</option>
+    <option value="50">50</option>
+</select></span>
+<span><label for="sort">Sort by: </label><select name="sort" id="sort">
+    <option value="0">Definition (ascending)</option>
+    <option value="1">Definition (descending)</option>
+    <option value="2">Name (ascending)</option>
+    <option value="3">Name (descending)</option>
+    <option value="4">Size (ascending)</option>
+    <option value="5">Size (descending)</option>
+</select></span>
+</body>
+<footer>
+    <p>&copy;<a href="https://hakurei.app/">Hakurei</a> (<span id="hakurei-version">unknown</span>). Licensed under the MIT license.</p>
+</footer>
+</html>

cmd/pkgserver/ui/static/dark.scss

@@ -0,0 +1,6 @@
+@use 'common';
+
+html {
+  background-color: #2c2c2c;
+  color: ghostwhite;
+}

cmd/pkgserver/ui/static/index.ts

@@ -0,0 +1,161 @@
+function assertGetElementById(id: string): HTMLElement {
+    let elem = document.getElementById(id)
+    if(elem == null) throw new ReferenceError(`element with ID '${id}' missing from DOM`)
+    return elem
+}
+
+interface PackageIndexEntry {
+    name: string
+    size: number | null
+    description: string | null
+    website: string | null
+    version: string | null
+    report:  boolean
+}
+function toHTML(entry: PackageIndexEntry): HTMLTableRowElement {
+    let v = entry.version != null ? `<span>${escapeHtml(entry.version)}</span>` : ""
+    let s = entry.size != null ? `<p>Size: ${toByteSizeString(entry.size)} (${entry.size})</p>` : ""
+    let d = entry.description != null ? `<p>${escapeHtml(entry.description)}</p>` : ""
+    let w = entry.website != null ? `<a href="${encodeURI(entry.website)}">Website</a>` : ""
+    let r = entry.report ? `Log (<a href=\"${encodeURI('/api/v1/status/' + entry.name)}\">View</a> | <a href=\"${encodeURI('/status/' + entry.name)}\">Download</a>)` : ""
+    let row = <HTMLTableRowElement>(document.createElement('tr'))
+    row.innerHTML = `<td>
+            <h2>${escapeHtml(entry.name)} ${v}</h2>
+            ${d}
+            ${s}
+            ${w}
+            ${r}
+        </td>`
+    return row
+}
+
+function toByteSizeString(bytes: number): string {
+    if(bytes == null || bytes < 1024) return `${bytes}B`
+    if(bytes < Math.pow(1024, 2)) return `${(bytes/1024).toFixed(2)}kiB`
+    if(bytes < Math.pow(1024, 3)) return `${(bytes/Math.pow(1024, 2)).toFixed(2)}MiB`
+    if(bytes < Math.pow(1024, 4)) return `${(bytes/Math.pow(1024, 3)).toFixed(2)}GiB`
+    if(bytes < Math.pow(1024, 5)) return `${(bytes/Math.pow(1024, 4)).toFixed(2)}TiB`
+    return "not only is it big, it's large"
+}
+
+const API_VERSION = 1
+const ENDPOINT = `/api/v${API_VERSION}`
+interface InfoPayload {
+    count: number
+    hakurei_version: string
+}
+
+async function infoRequest(): Promise<InfoPayload> {
+    const res = await fetch(`${ENDPOINT}/info`)
+    const payload = await res.json()
+    return payload
+}
+interface GetPayload {
+    values: PackageIndexEntry[]
+}
+
+enum SortOrders {
+    DeclarationAscending,
+    DeclarationDescending,
+    NameAscending,
+    NameDescending
+}
+async function getRequest(limit: number, index: number, sort: SortOrders): Promise<GetPayload> {
+    const res = await fetch(`${ENDPOINT}/get?limit=${limit}&index=${index}&sort=${sort.valueOf()}`)
+    const payload = await res.json()
+    return payload
+}
+class State {
+    entriesPerPage: number = 10
+    entryIndex: number = 0
+    maxEntries: number = 0
+    sort: SortOrders = SortOrders.DeclarationAscending
+
+    getEntriesPerPage(): number {
+        return this.entriesPerPage
+    }
+    setEntriesPerPage(entriesPerPage: number) {
+        this.entriesPerPage = entriesPerPage
+        this.setEntryIndex(Math.floor(this.getEntryIndex() / entriesPerPage) * entriesPerPage)
+    }
+    getEntryIndex(): number {
+        return this.entryIndex
+    }
+    setEntryIndex(entryIndex: number) {
+        this.entryIndex = entryIndex
+        this.updatePage()
+        this.updateRange()
+        this.updateListings()
+    }
+    getMaxEntries(): number {
+        return this.maxEntries
+    }
+    setMaxEntries(max: number) {
+        this.maxEntries = max
+    }
+    getSortOrder(): SortOrders {
+        return this.sort
+    }
+    setSortOrder(sortOrder: SortOrders) {
+        this.sort = sortOrder
+        this.setEntryIndex(0)
+    }
+    updatePage() {
+        let page = Math.ceil(((this.getEntryIndex() + this.getEntriesPerPage()) - 1) / this.getEntriesPerPage())
+        assertGetElementById("page-number").innerText = String(page)
+    }
+    updateRange() {
+        let max = Math.min(this.getEntryIndex() + this.getEntriesPerPage(), this.getMaxEntries())
+        assertGetElementById("entry-counter").innerText = `${this.getEntryIndex() + 1}-${max} of ${this.getMaxEntries()}`
+    }
+    updateListings() {
+        getRequest(this.getEntriesPerPage(), this.getEntryIndex(), this.getSortOrder())
+            .then(res => {
+                let table = assertGetElementById("pkg-list")
+                table.innerHTML = ''
+                res.values.forEach((row) => {
+                    table.appendChild(toHTML(row))
+                })
+            })
+    }
+
+}
+
+let STATE: State
+
+function prevPage() {
+    let index = STATE.getEntryIndex()
+    STATE.setEntryIndex(Math.max(0, index - STATE.getEntriesPerPage()))
+}
+function nextPage() {
+    let index = STATE.getEntryIndex()
+    STATE.setEntryIndex(Math.min((Math.ceil(STATE.getMaxEntries() / STATE.getEntriesPerPage()) * STATE.getEntriesPerPage()) - STATE.getEntriesPerPage(), index + STATE.getEntriesPerPage()))
+}
+
+function escapeHtml(str: string): string {
+    if(str === undefined) return ""
+    return str
+        .replace(/&/g, '&amp;')
+        .replace(/</g, '&lt;')
+        .replace(/>/g, '&gt;')
+        .replace(/"/g, '&quot;')
+        .replace(/'/g, '&apos;')
+}
+
+document.addEventListener("DOMContentLoaded", () => {
+    STATE = new State()
+    infoRequest()
+        .then(res => {
+            STATE.setMaxEntries(res.count)
+            assertGetElementById("hakurei-version").innerText = res.hakurei_version
+            STATE.updateRange()
+            STATE.updateListings()
+        })
+
+    assertGetElementById("count").addEventListener("change", (event) => {
+        STATE.setEntriesPerPage(parseInt((event.target as HTMLSelectElement).value))
+    })
+    assertGetElementById("sort").addEventListener("change", (event) => {
+        STATE.setSortOrder(parseInt((event.target as HTMLSelectElement).value))
+    })
+})

cmd/pkgserver/ui/static/light.scss

@@ -0,0 +1,6 @@
+@use 'common';
+
+html {
+  background-color: #d3d3d3;
+  color: black;
+}

cmd/pkgserver/ui/static/tsconfig.json

@@ -0,0 +1,6 @@
+{
+  "compilerOptions": {
+    "strict": true,
+    "target": "ES2024"
+  }
+}

cmd/pkgserver/ui_full.go

@@ -0,0 +1,9 @@
+//go:build frontend
+
+package main
+
+import "embed"
+
+//go:generate sh -c "sass ui/static/dark.scss ui/static/dark.css && sass ui/static/light.scss ui/static/light.css && tsc -p ui/static"
+//go:embed ui/*
+var content embed.FS

cmd/pkgserver/ui_stub.go

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

cmd/pkgserver/ui_test/all_tests.ts

@@ -0,0 +1,2 @@
+// Import all test files to execute their suite registrations.
+import "./test_tests.js";

cmd/pkgserver/ui_test/lib/cli.ts

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

cmd/pkgserver/ui_test/lib/failure-closed.svg

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

cmd/pkgserver/ui_test/lib/failure-open.svg

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

cmd/pkgserver/ui_test/lib/go_test_entrypoint.ts

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

cmd/pkgserver/ui_test/lib/skip-closed.svg

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

cmd/pkgserver/ui_test/lib/skip-open.svg

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

cmd/pkgserver/ui_test/lib/success-closed.svg

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

cmd/pkgserver/ui_test/lib/success-open.svg

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

cmd/pkgserver/ui_test/lib/test.ts

@@ -0,0 +1,400 @@
+// =============================================================================
+// DSL
+
+type TestTree = TestGroup | Test;
+type TestGroup = { name: string, children: TestTree[] };
+type Test = { name: string, test: (t: TestController) => void };
+
+export class TestRegistrar {
+    #suites: TestGroup[];
+
+    constructor() {
+        this.#suites = [];
+    }
+
+    suite(name: string, children: TestTree[]) {
+        checkDuplicates(name, children)
+        this.#suites.push({ name, children });
+    }
+
+    run(reporter: Reporter) {
+        reporter.register(this.#suites);
+        for (const suite of this.#suites) {
+            for (const c of suite.children) runTests(reporter, [suite.name], c);
+        }
+        reporter.finalize();
+    }
+}
+
+export let TESTS = new TestRegistrar();
+
+// Register a suite in the global registrar.
+export function suite(name: string, children: TestTree[]) {
+    TESTS.suite(name, children);
+}
+
+export function context(name: string, children: TestTree[]): TestTree {
+    checkDuplicates(name, children);
+    return { name, children };
+}
+export const group = context;
+
+export function test(name: string, test: (t: TestController) => void): TestTree {
+    return { name, test };
+}
+
+function checkDuplicates(parent: string, names: { name: string }[]) {
+    let seen = new Set<string>();
+    for (const { name } of names) {
+        if (seen.has(name)) {
+            throw new RangeError(`duplicate name '${name}' in '${parent}'`);
+        }
+        seen.add(name);
+    }
+}
+
+export type TestState = "success" | "failure" | "skip";
+
+class AbortSentinel {}
+
+export class TestController {
+    #state: TestState;
+    logs: string[];
+
+    constructor() {
+        this.#state = "success";
+        this.logs = [];
+    }
+
+    getState(): TestState {
+        return this.#state;
+    }
+
+    fail() {
+        this.#state = "failure";
+    }
+
+    failed(): boolean {
+        return this.#state === "failure";
+    }
+
+    failNow(): never {
+        this.fail();
+        throw new AbortSentinel();
+    }
+
+    log(message: string) {
+        this.logs.push(message);
+    }
+
+    error(message: string) {
+        this.log(message);
+        this.fail();
+    }
+
+    fatal(message: string): never {
+        this.log(message);
+        this.failNow();
+    }
+
+    skip(message?: string): never {
+        if (message != null) this.log(message);
+        if (this.#state !== "failure") this.#state = "skip";
+        throw new AbortSentinel();
+    }
+
+    skipped(): boolean {
+        return this.#state === "skip";
+    }
+}
+
+// =============================================================================
+// Execution
+
+export interface TestResult {
+    state: TestState;
+    logs: string[];
+}
+
+function runTests(reporter: Reporter, parents: string[], node: TestTree) {
+    const path = [...parents, node.name];
+    if ("children" in node) {
+        for (const c of node.children) runTests(reporter, path, c);
+        return;
+    }
+    let controller = new TestController();
+    try {
+        node.test(controller);
+    } catch (e) {
+        if (!(e instanceof AbortSentinel)) {
+            controller.error(extractExceptionString(e));
+        }
+    }
+    reporter.update(path, { state: controller.getState(), logs: controller.logs });
+}
+
+function extractExceptionString(e: any): string {
+    // String() instead of .toString() as null and undefined don't have
+    // properties.
+    const s = String(e);
+    if (!(e instanceof Error && e.stack)) return s;
+    // v8 (Chromium, NodeJS) includes the error message, while Firefox and
+    // WebKit do not.
+    if (e.stack.startsWith(s)) return e.stack;
+    return `${s}\n${e.stack}`;
+}
+
+// =============================================================================
+// Reporting
+
+export interface Reporter {
+    register(suites: TestGroup[]): void
+    update(path: string[], result: TestResult): void;
+    finalize(): void;
+}
+
+export class NoOpReporter implements Reporter {
+    suites: TestGroup[];
+    results: ({ path: string[] } & TestResult)[];
+    finalized: boolean;
+
+    constructor() {
+        this.suites = [];
+        this.results = [];
+        this.finalized = false;
+    }
+
+    register(suites: TestGroup[]) {
+        this.suites = suites;
+    }
+
+    update(path: string[], result: TestResult) {
+        this.results.push({ path, ...result });
+    }
+
+    finalize() {
+        this.finalized = true;
+    }
+}
+
+export interface Stream {
+    writeln(s: string): void;
+}
+
+const SEP = " ❯ ";
+
+export class StreamReporter implements Reporter {
+    stream: Stream;
+    verbose: boolean;
+    #successes: ({ path: string[] } & TestResult)[];
+    #failures: ({ path: string[] } & TestResult)[];
+    #skips: ({ path: string[] } & TestResult)[];
+
+    constructor(stream: Stream, verbose: boolean = false) {
+        this.stream = stream;
+        this.verbose = verbose;
+        this.#successes = [];
+        this.#failures = [];
+        this.#skips = [];
+    }
+
+    succeeded(): boolean {
+        return this.#successes.length > 0 && this.#failures.length === 0;
+    }
+
+    register(suites: TestGroup[]) {}
+
+    update(path: string[], result: TestResult) {
+        if (path.length === 0) throw new RangeError("path is empty");
+        const pathStr = path.join(SEP);
+        switch (result.state) {
+        case "success":
+            this.#successes.push({ path, ...result });
+            if (this.verbose) this.stream.writeln(`✅️ ${pathStr}`);
+            break;
+        case "failure":
+            this.#failures.push({ path, ...result });
+            this.stream.writeln(`⚠️ ${pathStr}`);
+            break;
+        case "skip":
+            this.#skips.push({ path, ...result });
+            this.stream.writeln(`⏭️ ${pathStr}`);
+            break;
+        }
+    }
+
+    finalize() {
+        if (this.verbose) this.#displaySection("successes", this.#successes, true);
+        this.#displaySection("failures", this.#failures);
+        this.#displaySection("skips", this.#skips);
+        this.stream.writeln("");
+        this.stream.writeln(
+            `${this.#successes.length} succeeded, ${this.#failures.length} failed`
+            + (this.#skips.length ? `, ${this.#skips.length} skipped` : "")
+        );
+    }
+
+    #displaySection(name: string, data: ({ path: string[] } & TestResult)[], ignoreEmpty: boolean = false) {
+        if (!data.length) return;
+
+        // Transform [{ path: ["a", "b", "c"] }, { path: ["a", "b", "d"] }]
+        // into { "a ❯ b": ["c", "d"] }.
+        let pathMap = new Map<string, ({ name: string } & TestResult)[]>();
+        for (const t of data) {
+            if (t.path.length === 0) throw new RangeError("path is empty");
+            const key = t.path.slice(0, -1).join(SEP);
+            if (!pathMap.has(key)) pathMap.set(key, []);
+            pathMap.get(key)!.push({ name: t.path.at(-1)!, ...t });
+        }
+
+        this.stream.writeln("");
+        this.stream.writeln(name.toUpperCase());
+        this.stream.writeln("=".repeat(name.length));
+
+        for (let [path, tests] of pathMap) {
+            if (ignoreEmpty) tests = tests.filter((t) => t.logs.length);
+            if (tests.length === 0) continue;
+            if (tests.length === 1) {
+                this.#writeOutput(tests[0], path ? `${path}${SEP}` : "", false);
+            } else {
+                this.stream.writeln(path);
+                for (const t of tests) this.#writeOutput(t, "  - ", true);
+            }
+        }
+    }
+
+    #writeOutput(test: { name: string } & TestResult, prefix: string, nested: boolean) {
+        let output = "";
+        if (test.logs.length) {
+            // Individual logs might span multiple lines, so join them together
+            // then split it again.
+            const logStr = test.logs.join("\n");
+            const lines = logStr.split("\n");
+            if (lines.length <= 1) {
+                output = `: ${logStr}`;
+            } else {
+                const padding = nested ? "      " : "  ";
+                output = ":\n" + lines.map((line) => padding + line).join("\n");
+            }
+        }
+        this.stream.writeln(`${prefix}${test.name}${output}`);
+    }
+}
+
+function assertGetElementById(id: string): HTMLElement {
+    let elem = document.getElementById(id);
+    if (elem == null) throw new ReferenceError(`element with ID '${id}' missing from DOM`);
+    return elem;
+}
+
+export class DOMReporter implements Reporter {
+    register(suites: TestGroup[]) {}
+
+    update(path: string[], result: TestResult) {
+        if (path.length === 0) throw new RangeError("path is empty");
+        if (result.state === "skip") {
+            assertGetElementById("skip-counter-text").classList.remove("hidden");
+        }
+        const counter = assertGetElementById(`${result.state}-counter`);
+        counter.innerText = (Number(counter.innerText) + 1).toString();
+
+        let parent = assertGetElementById("root");
+        for (const node of path) {
+            let child: HTMLDetailsElement | null = null;
+            let summary: HTMLElement | null = null;
+            let d: Element;
+            outer: for (d of parent.children) {
+                if (!(d instanceof HTMLDetailsElement)) continue;
+                for (const s of d.children) {
+                    if (!(s instanceof HTMLElement)) continue;
+                    if (!(s.tagName === "SUMMARY" && s.innerText === node)) continue;
+                    child = d;
+                    summary = s;
+                    break outer;
+                }
+            }
+            if (!child) {
+                child = document.createElement("details");
+                child.className = "test-node";
+                child.ariaRoleDescription = "test";
+                summary = document.createElement("summary");
+                summary.appendChild(document.createTextNode(node));
+                summary.ariaRoleDescription = "test name";
+                child.appendChild(summary);
+                parent.appendChild(child);
+            }
+            if (!summary) throw new Error("unreachable as assigned above");
+
+            switch (result.state) {
+            case "failure":
+                child.open = true;
+                child.classList.add("failure");
+                child.classList.remove("skip");
+                child.classList.remove("success");
+                summary.setAttribute("aria-labelledby", "failure-description");
+                break;
+            case "skip":
+                if (child.classList.contains("failure")) break;
+                child.classList.add("skip");
+                child.classList.remove("success");
+                summary.setAttribute("aria-labelledby", "skip-description");
+                break;
+            case "success":
+                if (child.classList.contains("failure") || child.classList.contains("skip")) break;
+                child.classList.add("success");
+                summary.setAttribute("aria-labelledby", "success-description");
+                break;
+            }
+
+            parent = child;
+        }
+
+        const p = document.createElement("p");
+        p.classList.add("test-desc");
+        if (result.logs.length) {
+            const pre = document.createElement("pre");
+            pre.appendChild(document.createTextNode(result.logs.join("\n")));
+            p.appendChild(pre);
+        } else {
+            p.classList.add("italic");
+            p.appendChild(document.createTextNode("No output."));
+        }
+        parent.appendChild(p);
+    }
+
+    finalize() {}
+}
+
+interface GoNode {
+    name: string;
+    subtests: GoNode[] | null;
+}
+
+// Used to display results via `go test`, via some glue code from the Go side.
+export class GoTestReporter implements Reporter {
+    // Convert a test tree into the one expected by the Go code.
+    static serialize(node: TestTree): GoNode {
+        return {
+            name: node.name,
+            subtests: "children" in node ? node.children.map(GoTestReporter.serialize) : null,
+        };
+    }
+
+    register(suites: TestGroup[]) {
+        console.log(JSON.stringify(suites.map(GoTestReporter.serialize)));
+    }
+
+    update(path: string[], result: TestResult) {
+        let state: number;
+        switch (result.state) {
+            case "success": state = 0; break;
+            case "failure": state = 1; break;
+            case "skip": state = 2; break;
+        }
+        console.log(JSON.stringify({ path: path, state, logs: result.logs }));
+    }
+
+    finalize() {
+        console.log("null");
+    }
+}

cmd/pkgserver/ui_test/lib/ui.html

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

cmd/pkgserver/ui_test/lib/ui.scss

@@ -0,0 +1,87 @@
+:root {
+    --bg: #d3d3d3;
+    --fg: black;
+}
+
+@media (prefers-color-scheme: dark) {
+    :root {
+        --bg: #2c2c2c;
+        --fg: ghostwhite;
+    }
+}
+
+html {
+    background-color: var(--bg);
+    color: var(--fg);
+}
+
+h1, p, summary, noscript {
+    font-family: sans-serif;
+}
+
+noscript {
+    font-size: 16pt;
+}
+
+.root {
+    margin: 1rem 0;
+}
+
+details.test-node {
+    margin-left: 1rem;
+    padding: 0.2rem 0.5rem;
+    border-left: 2px dashed var(--fg);
+    > summary {
+        cursor: pointer;
+    }
+    &.success > summary::marker {
+        /*
+         * WebKit only supports color and font-size properties in ::marker [1],
+         * and its ::-webkit-details-marker only supports hiding the marker
+         * entirely [2], contrary to mdn's example [3]; thus, set a color as
+         * a fallback: while it may not be accessible for colorblind
+         * individuals, it's better than no indication of a test's state for
+         * anyone, as that there's no other way to include an indication in the
+         * marker on WebKit.
+         *
+         * [1]: https://developer.mozilla.org/en-US/docs/Web/CSS/Reference/Selectors/::marker#browser_compatibility
+         * [2]: https://developer.mozilla.org/en-US/docs/Web/HTML/Reference/Elements/summary#default_style
+         * [3]: https://developer.mozilla.org/en-US/docs/Web/HTML/Reference/Elements/summary#changing_the_summarys_icon
+         */
+        color: var(--fg);
+        content: url("/testui/success-closed.svg") / "success";
+    }
+    &.success[open] > summary::marker {
+        content: url("/testui/success-open.svg") / "success";
+    }
+    &.failure > summary::marker {
+        color: red;
+        content: url("/testui/failure-closed.svg") / "failure";
+    }
+    &.failure[open] > summary::marker {
+        content: url("/testui/failure-open.svg") / "failure";
+    }
+    &.skip > summary::marker {
+        color: blue;
+        content: url("/testui/skip-closed.svg") / "skip";
+    }
+    &.skip[open] > summary::marker {
+        content: url("/testui/skip-open.svg") / "skip";
+    }
+}
+
+p.test-desc {
+    margin: 0 0 0 1rem;
+    padding: 2px 0;
+    > pre {
+        margin: 0;
+    }
+}
+
+.hidden {
+    display: none;
+}
+
+.italic {
+    font-style: italic;
+}

cmd/pkgserver/ui_test/test_tests.ts

@@ -0,0 +1,85 @@
+import { NoOpReporter, TestRegistrar, context, group, suite, test } from "./lib/test.js";
+
+suite("dog", [
+    group("tail", [
+        test("wags when happy", (t) => {
+            if (0 / 0 !== Infinity / Infinity) {
+                t.fatal("undefined must not be defined");
+            }
+        }),
+        test("idle when down", (t) => {
+            t.log("test test");
+            t.error("dog whining noises go here");
+        }),
+    ]),
+    test("likes headpats", (t) => {
+        if (2 !== 2) {
+            t.error("IEEE 754 violated: 2 is NaN");
+        }
+    }),
+    context("near cat", [
+        test("is ecstatic", (t) => {
+            if (("b" + "a" + + "a" + "a").toLowerCase() === "banana") {
+                t.error("🍌🍌🍌");
+                t.error("🍌🍌🍌");
+                t.error("🍌🍌🍌");
+                t.failNow();
+            }
+        }),
+        test("playfully bites cats' tails", (t) => {
+            t.log("arf!");
+            throw new Error("nom");
+        }),
+    ]),
+]);
+
+suite("cat", [
+    test("likes headpats", (t) => {
+        t.log("meow");
+    }),
+    test("owns skipping rope", (t) => {
+        t.skip("this cat is stuck in your machine!");
+        t.log("never logged");
+    }),
+    test("tester tester", (t) => {
+        const r = new TestRegistrar();
+        r.suite("explod", [
+            test("with yarn", (t) => {
+                t.log("YAY");
+            }),
+        ]);
+        const reporter = new NoOpReporter();
+        r.run(reporter);
+        if (reporter.suites.length !== 1) {
+            t.fatal(`incorrect number of suites registered got=${reporter.suites.length} want=1`);
+        }
+        const suite = reporter.suites[0];
+        if (suite.name !== "explod") {
+            t.error(`suite name incorrect got='${suite.name}' want='explod'`);
+        }
+        if (suite.children.length !== 1) {
+            t.fatal(`incorrect number of suite children got=${suite.children.length} want=1`);
+        }
+        const test_ = suite.children[0];
+        if (test_.name !== "with yarn") {
+            t.error(`incorrect test name got='${test_.name}' want='with yarn'`);
+        }
+        if ("children" in test_) {
+            t.error(`expected leaf node, got group of ${test_.children.length} children`);
+        }
+        if (!reporter.finalized) t.error(`expected reporter to have been finalized`);
+        if (reporter.results.length !== 1) {
+            t.fatal(`incorrect result count got=${reporter.results.length} want=1`);
+        }
+        const result = reporter.results[0];
+        if (!(result.path.length === 2 &&
+              result.path[0] === "explod" &&
+              result.path[1] === "with yarn")) {
+            t.error(`incorrect result path got=${result.path} want=["explod", "with yarn"]`);
+        }
+        if (result.state !== "success") t.error(`expected test to succeed`);
+        if (!(result.logs.length === 1 && result.logs[0] === "YAY")) {
+            t.error(`incorrect result logs got=${result.logs} want=["YAY"]`);
+        }
+    }),
+]);

cmd/pkgserver/ui_test/tsconfig.json

@@ -0,0 +1,6 @@
+{
+  "compilerOptions": {
+    "strict": true,
+    "target": "ES2024"
+  }
+}

cmd/sharefs/fuse-operations.h

@@ -7,8 +7,8 @@
 #endif
 
 #define SHAREFS_MEDIA_RW_ID (1 << 10) - 1 /* owning gid presented to userspace */
-#define SHAREFS_PERM_DIR 0700             /* permission bits for directories presented to userspace */
-#define SHAREFS_PERM_REG 0600             /* permission bits for regular files 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 */

cmd/sharefs/fuse.go

@@ -19,12 +19,11 @@ import (
 	"encoding/gob"
 	"errors"
 	"fmt"
-	"io"
 	"log"
 	"os"
 	"os/exec"
 	"os/signal"
-	"path"
+	"path/filepath"
 	"runtime"
 	"runtime/cgo"
 	"strconv"
@@ -85,7 +84,10 @@ func destroySetup(private_data unsafe.Pointer) (ok bool) {
 }
 
 //export sharefs_init
-func sharefs_init(_ *C.struct_fuse_conn_info, cfg *C.struct_fuse_config) unsafe.Pointer {
+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)
@@ -103,7 +105,11 @@ func sharefs_init(_ *C.struct_fuse_conn_info, cfg *C.struct_fuse_config) unsafe.
 	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 {
+	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 {
@@ -138,9 +144,9 @@ func sharefs_destroy(private_data unsafe.Pointer) {
 func showHelp(args *fuseArgs) {
 	executableName := sharefsName
 	if args.argc > 0 {
-		executableName = path.Base(C.GoString(*args.argv))
+		executableName = filepath.Base(C.GoString(*args.argv))
 	} else if name, err := os.Executable(); err == nil {
-		executableName = path.Base(name)
+		executableName = filepath.Base(name)
 	}
 
 	fmt.Printf("usage: %s [options] <mountpoint>\n\n", executableName)
@@ -169,8 +175,11 @@ func parseOpts(args *fuseArgs, setup *setupState, log *log.Logger) (ok bool) {
 		// 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.
+		// 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
 	}
 
@@ -253,7 +262,8 @@ func parseOpts(args *fuseArgs, setup *setupState, log *log.Logger) (ok bool) {
 	return true
 }
 
-// copyArgs returns a heap allocated copy of an argument slice in fuse_args representation.
+// 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}
@@ -269,6 +279,7 @@ func copyArgs(s ...string) fuseArgs {
 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))))
@@ -288,8 +299,8 @@ func _main(s ...string) (exitCode int) {
 	args := copyArgs(s...)
 	defer freeArgs(&args)
 
-	// this causes the kernel to enforce access control based on
-	// struct stat populated by sharefs_getattr
+	// 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
@@ -453,15 +464,19 @@ func _main(s ...string) (exitCode int) {
 			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")))
+		setup.Fuse = int(proc.ExtraFileSlice(
+			&z.ExtraFiles,
+			os.NewFile(uintptr(C.fuse_session_fd(se)), "fuse"),
+		))
 
-		var setupWriter io.WriteCloser
-		if fd, w, err := container.Setup(&z.ExtraFiles); err != nil {
+		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(fd))
-			setupWriter = w
+			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 {
@@ -472,6 +487,9 @@ func _main(s ...string) (exitCode int) {
 			}
 			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)
@@ -481,10 +499,10 @@ func _main(s ...string) (exitCode int) {
 			return 5
 		}
 
-		if err := gob.NewEncoder(setupWriter).Encode(&setup); err != nil {
+		if err := gob.NewEncoder(setupPipe[1]).Encode(&setup); err != nil {
 			log.Println(err)
 			return 5
-		} else if err = setupWriter.Close(); err != nil {
+		} else if err = setupPipe[1].Close(); err != nil {
 			log.Println(err)
 		}
 

cmd/sharefs/main.go

@@ -1,3 +1,10 @@
+// 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 (

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())
+	}
+}

container/container.go

@@ -28,9 +28,6 @@ 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 (
@@ -53,7 +50,7 @@ type (
 		ExtraFiles []*os.File
 
 		// Write end of a pipe connected to the init to deliver [Params].
-		setup *os.File
+		setup [2]*os.File
 		// Cancels the context passed to the underlying cmd.
 		cancel context.CancelFunc
 		// Closed after Wait returns. Keeps the spawning thread alive.
@@ -287,14 +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 {
+	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...)
@@ -324,9 +323,9 @@ func (p *Container) Start() error {
 				}
 
 				if abi, err := LandlockGetABI(); err != nil {
-					if p.HostAbstract {
+					if p.HostAbstract || !p.HostNet {
 						// landlock can be skipped here as it restricts access
-						// to resources already covered by namespaces (pid)
+						// to resources already covered by namespaces (pid, net)
 						goto landlockOut
 					}
 					return &StartError{Step: "get landlock ABI", Err: err}
@@ -428,24 +427,33 @@ 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 {
+	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:        "set init pipe deadline",
+			Step:        "close read end of init pipe",
 			Err:         err,
 			Passthrough: true,
 		}
 	}
 
 	if p.Path == nil {
-		p.cancel()
 		return &StartError{
 			Step:   "invalid executable pathname",
 			Err:    EINVAL,
@@ -461,18 +469,27 @@ 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 blocks until the container init process to exit and releases any

container/container_test.go

@@ -16,7 +16,6 @@ import (
 	"strings"
 	"syscall"
 	"testing"
-	"time"
 
 	"hakurei.app/check"
 	"hakurei.app/command"
@@ -26,6 +25,8 @@ import (
 	"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"
@@ -84,9 +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{
@@ -436,11 +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)
@@ -450,7 +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
@@ -458,6 +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).
@@ -553,11 +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)
 		}
@@ -738,8 +743,7 @@ func init() {
 const (
 	envDoCheck = "HAKUREI_TEST_DO_CHECK"
 
-	helperDefaultTimeout = 5 * time.Second
-	helperInnerPath      = "/usr/bin/helper"
+	helperInnerPath = "/usr/bin/helper"
 )
 
 var (

container/dispatcher.go

@@ -1,6 +1,7 @@
 package container
 
 import (
+	"context"
 	"io"
 	"io/fs"
 	"net"
@@ -15,6 +16,7 @@ import (
 	"hakurei.app/container/std"
 	"hakurei.app/ext"
 	"hakurei.app/internal/netlink"
+	"hakurei.app/internal/params"
 	"hakurei.app/message"
 )
 
@@ -55,7 +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
@@ -66,7 +68,7 @@ type syscallDispatcher interface {
 	// ensureFile provides ensureFile.
 	ensureFile(name string, perm, pperm os.FileMode) error
 	// mustLoopback provides mustLoopback.
-	mustLoopback(msg message.Msg)
+	mustLoopback(ctx context.Context, msg message.Msg)
 
 	// seccompLoad provides [seccomp.Load].
 	seccompLoad(rules []std.NativeRule, flags seccomp.ExportFlag) error
@@ -154,8 +156,8 @@ func (direct) capBoundingSetDrop(cap uintptr) error            { return capBound
 func (direct) capAmbientClearAll() error                       { return capAmbientClearAll() }
 func (direct) capAmbientRaise(cap uintptr) error               { return capAmbientRaise(cap) }
 func (direct) isatty(fd int) bool                              { return ext.Isatty(fd) }
-func (direct) receive(key string, e any, fdp *uintptr) (func() error, error) {
-	return Receive(key, e, fdp)
+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 {
@@ -170,7 +172,7 @@ 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(msg message.Msg) {
+func (direct) mustLoopback(ctx context.Context, msg message.Msg) {
 	var lo int
 	if ifi, err := net.InterfaceByName("lo"); err != nil {
 		msg.GetLogger().Fatalln(err)
@@ -178,7 +180,7 @@ func (direct) mustLoopback(msg message.Msg) {
 		lo = ifi.Index
 	}
 
-	c, err := netlink.DialRoute()
+	c, err := netlink.DialRoute(0)
 	if err != nil {
 		msg.GetLogger().Fatalln(err)
 	}
@@ -199,11 +201,14 @@ func (direct) mustLoopback(msg message.Msg) {
 			msg.GetLogger().Fatalf("RTNETLINK answers: %v", err)
 
 		default:
-			msg.GetLogger().Fatalf("RTNETLINK answers with malformed message")
+			if err == context.DeadlineExceeded || err == context.Canceled {
+				msg.GetLogger().Fatalf("interrupted RTNETLINK operation")
+			}
+			msg.GetLogger().Fatal("RTNETLINK answers with malformed message")
 		}
 	}
-	must(c.SendNewaddrLo(uint32(lo)))
-	must(c.SendIfInfomsg(syscall.RTM_NEWLINK, 0, &syscall.IfInfomsg{
+	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,

container/dispatcher_test.go

@@ -2,6 +2,7 @@ package container
 
 import (
 	"bytes"
+	"context"
 	"fmt"
 	"io"
 	"io/fs"
@@ -389,7 +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")
 
@@ -407,10 +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 {
@@ -425,7 +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)
 			}
 		}
 	}
@@ -468,7 +476,7 @@ func (k *kstub) ensureFile(name string, perm, pperm os.FileMode) error {
 		stub.CheckArg(k.Stub, "pperm", pperm, 2))
 }
 
-func (*kstub) mustLoopback(message.Msg) { /* noop */ }
+func (*kstub) mustLoopback(context.Context, message.Msg) { /* noop */ }
 
 func (k *kstub) seccompLoad(rules []std.NativeRule, flags seccomp.ExportFlag) error {
 	k.Helper()

container/init.go

@@ -7,7 +7,8 @@ import (
 	"log"
 	"os"
 	"os/exec"
-	"path"
+	"os/signal"
+	"path/filepath"
 	"slices"
 	"strconv"
 	"sync"
@@ -18,6 +19,7 @@ import (
 	"hakurei.app/container/seccomp"
 	"hakurei.app/ext"
 	"hakurei.app/fhs"
+	"hakurei.app/internal/params"
 	"hakurei.app/message"
 )
 
@@ -146,36 +148,38 @@ 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 !params.HostNet {
-		k.mustLoopback(msg)
+	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
@@ -183,7 +187,7 @@ func initEntrypoint(k syscallDispatcher, msg message.Msg) {
 		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)
 	}
@@ -193,7 +197,7 @@ 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)
 	}
@@ -202,8 +206,8 @@ func initEntrypoint(k syscallDispatcher, msg message.Msg) {
 	}
 
 	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)
 		}
 	}
@@ -216,7 +220,7 @@ 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;
@@ -224,7 +228,7 @@ func initEntrypoint(k syscallDispatcher, msg message.Msg) {
 	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 {
+	for i, op := range *param.Ops {
 		if op == nil || !op.Valid() {
 			k.fatalf(msg, "invalid op at index %d", i)
 		}
@@ -267,7 +271,7 @@ func initEntrypoint(k syscallDispatcher, msg message.Msg) {
 	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 *params.Ops {
+	for i, op := range *param.Ops {
 		// ops already checked during early setup
 		if prefix, ok := op.prefix(); ok {
 			msg.Verbosef("%s %s", prefix, op)
@@ -323,7 +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 {
@@ -332,7 +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 {
@@ -346,13 +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)
 		}
@@ -361,10 +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)
 
@@ -442,7 +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 {
@@ -463,14 +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)
 	}
@@ -488,9 +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
@@ -520,7 +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 {
@@ -564,7 +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

@@ -10,6 +10,7 @@ import (
 	"hakurei.app/check"
 	"hakurei.app/container/seccomp"
 	"hakurei.app/container/std"
+	"hakurei.app/internal/params"
 	"hakurei.app/internal/stub"
 )
 
@@ -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},

container/initdev.go

@@ -3,7 +3,7 @@ package container
 import (
 	"encoding/gob"
 	"fmt"
-	"path"
+	"path/filepath"
 	. "syscall"
 
 	"hakurei.app/check"
@@ -46,7 +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
 		}
@@ -62,7 +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
 		}
@@ -72,13 +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
@@ -92,7 +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
 			}
@@ -110,7 +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/initsymlink.go

@@ -3,7 +3,7 @@ package container
 import (
 	"encoding/gob"
 	"fmt"
-	"path"
+	"path/filepath"
 
 	"hakurei.app/check"
 )
@@ -30,7 +30,7 @@ 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) {
+		if !filepath.IsAbs(l.LinkName) {
 			return check.AbsoluteError(l.LinkName)
 		}
 		if name, err := k.readlink(l.LinkName); err != nil {
@@ -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/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

@@ -4,7 +4,7 @@ import (
 	"errors"
 	"io/fs"
 	"os"
-	"path"
+	"path/filepath"
 	"strconv"
 	"strings"
 	"syscall"
@@ -29,16 +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

@@ -4,7 +4,7 @@ import (
 	"io"
 	"math"
 	"os"
-	"path"
+	"path/filepath"
 	"reflect"
 	"syscall"
 	"testing"
@@ -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)
 				}
 

dist/hsurc.default

@@ -1 +0,0 @@
-1000 0

dist/install.sh

@@ -1,12 +0,0 @@
-#!/bin/sh
-cd "$(dirname -- "$0")" || exit 1
-
-install -vDm0755 "bin/hakurei" "${DESTDIR}/usr/bin/hakurei"
-install -vDm0755 "bin/sharefs" "${DESTDIR}/usr/bin/sharefs"
-
-install -vDm4511 "bin/hsu" "${DESTDIR}/usr/bin/hsu"
-if [ ! -f "${DESTDIR}/etc/hsurc" ]; then
-    install -vDm0400 "hsurc.default" "${DESTDIR}/etc/hsurc"
-fi
-
-install -vDm0644 "comp/_hakurei" "${DESTDIR}/usr/share/zsh/site-functions/_hakurei"

dist/release.sh

@@ -1,31 +0,0 @@
-#!/bin/sh -e
-cd "$(dirname -- "$0")/.."
-VERSION="${HAKUREI_VERSION:-untagged}"
-pname="hakurei-${VERSION}-$(go env GOARCH)"
-out="${DESTDIR:-dist}/${pname}"
-
-echo '# Preparing distribution files.'
-mkdir -p "${out}"
-cp -v "README.md" "dist/hsurc.default" "dist/install.sh" "${out}"
-cp -rv "dist/comp" "${out}"
-echo
-
-echo '# Building hakurei.'
-go generate ./...
-go build -trimpath -v -o "${out}/bin/" -ldflags "-s -w
-  -buildid= -linkmode external -extldflags=-static
-  -X hakurei.app/internal/info.buildVersion=${VERSION}
-  -X hakurei.app/internal/info.hakureiPath=/usr/bin/hakurei
-  -X hakurei.app/internal/info.hsuPath=/usr/bin/hsu
-  -X main.hakureiPath=/usr/bin/hakurei" ./...
-echo
-
-echo '# Testing hakurei.'
-go test -ldflags='-buildid= -linkmode external -extldflags=-static' ./...
-echo
-
-echo '# Creating distribution.'
-rm -f "${out}.tar.gz" && tar -C "${out}/.." -vczf "${out}.tar.gz" "${pname}"
-rm -rf "${out}"
-(cd "${out}/.." && sha512sum "${pname}.tar.gz" > "${pname}.tar.gz.sha512")
-echo

flake.nix

@@ -137,11 +137,10 @@
 
                 CC="musl-clang -O3 -Werror -Qunused-arguments" \
                 GOCACHE="$(mktemp -d)" \
-                HAKUREI_TEST_SKIP_ACL=1 \
                 PATH="${pkgs.pkgsStatic.musl.bin}/bin:$PATH" \
                 DESTDIR="$out" \
                 HAKUREI_VERSION="v${hakurei.version}" \
-                  ./dist/release.sh
+                  ./all.sh
               '';
         }
       );
@@ -196,6 +195,7 @@
                   ./test/interactive/vm.nix
                   ./test/interactive/hakurei.nix
                   ./test/interactive/trace.nix
+                  ./test/interactive/raceattr.nix
 
                   self.nixosModules.hakurei
                   home-manager.nixosModules.home-manager

hst/fs.go

@@ -56,8 +56,10 @@ type Ops interface {
 
 // ApplyState holds the address of [Ops] and any relevant application state.
 type ApplyState struct {
-	// AutoEtcPrefix is the prefix for [FSBind] in autoetc [FSBind.Special] condition.
+	// Prefix for [FSBind] in autoetc [FSBind.Special] condition.
 	AutoEtcPrefix string
+	// Whether to skip remounting root.
+	NoRemountRoot bool
 
 	Ops
 }

hst/fslink.go

@@ -2,7 +2,7 @@ package hst
 
 import (
 	"encoding/gob"
-	"path"
+	"path/filepath"
 
 	"hakurei.app/check"
 )
@@ -28,7 +28,7 @@ func (l *FSLink) Valid() bool {
 	if l == nil || l.Target == nil || l.Linkname == "" {
 		return false
 	}
-	return !l.Dereference || path.IsAbs(l.Linkname)
+	return !l.Dereference || filepath.IsAbs(l.Linkname)
 }
 
 func (l *FSLink) Path() *check.Absolute {

hst/fsoverlay.go

@@ -5,6 +5,7 @@ import (
 	"strings"
 
 	"hakurei.app/check"
+	"hakurei.app/fhs"
 )
 
 func init() { gob.Register(new(FSOverlay)) }
@@ -69,9 +70,12 @@ func (o *FSOverlay) Apply(z *ApplyState) {
 		return
 	}
 
-	if o.Upper != nil && o.Work != nil { // rw
+	if o.Upper != nil && o.Work != nil {
 		z.Overlay(o.Target, o.Upper, o.Work, o.Lower...)
-	} else { // ro
+		if o.Target.Is(fhs.AbsRoot) {
+			z.NoRemountRoot = true
+		}
+	} else {
 		z.OverlayReadonly(o.Target, o.Lower...)
 	}
 }

hst/fsoverlay_test.go

@@ -49,5 +49,18 @@ func TestFSOverlay(t *testing.T) {
 			Lower:  ms("/tmp/.src0", "/tmp/.src1"),
 		}}, m("/mnt/src"), ms("/tmp/.src0", "/tmp/.src1"),
 			"*/mnt/src:/tmp/.src0:/tmp/.src1"},
+
+		{"no remount root", &hst.FSOverlay{
+			Target: m("/"),
+			Lower:  ms("/tmp/.src0", "/tmp/.src1"),
+			Upper:  m("/tmp/upper"),
+			Work:   m("/tmp/work"),
+		}, true, container.Ops{&container.MountOverlayOp{
+			Target: m("/"),
+			Lower:  ms("/tmp/.src0", "/tmp/.src1"),
+			Upper:  m("/tmp/upper"),
+			Work:   m("/tmp/work"),
+		}}, m("/"), ms("/tmp/upper", "/tmp/work", "/tmp/.src0", "/tmp/.src1"),
+			"w*/:/tmp/upper:/tmp/work:/tmp/.src0:/tmp/.src1"},
 	})
 }

internal/acl/acl_test.go

@@ -8,12 +8,14 @@ import (
 	"io"
 	"os"
 	"os/exec"
-	"path"
+	"path/filepath"
 	"reflect"
 	"strconv"
+	"syscall"
 	"testing"
 
 	"hakurei.app/internal/acl"
+	"hakurei.app/internal/info"
 )
 
 const testFileName = "acl.test"
@@ -24,11 +26,17 @@ var (
 )
 
 func TestUpdate(t *testing.T) {
-	if os.Getenv("HAKUREI_TEST_SKIP_ACL") == "1" {
-		t.Skip("acl test skipped")
+	if info.CanDegrade {
+		name := filepath.Join(t.TempDir(), "check-degrade")
+		if err := os.WriteFile(name, nil, 0); err != nil {
+			t.Fatal(err)
+		}
+		if err := acl.Update(name, os.Geteuid()); errors.Is(err, syscall.ENOTSUP) {
+			t.Skip(err)
+		}
 	}
 
-	testFilePath := path.Join(t.TempDir(), testFileName)
+	testFilePath := filepath.Join(t.TempDir(), testFileName)
 
 	if f, err := os.Create(testFilePath); err != nil {
 		t.Fatalf("Create: error = %v", err)

internal/info/optional_skip.go

@@ -0,0 +1,7 @@
+//go:build !noskip
+
+package info
+
+// CanDegrade is whether tests are allowed to transparently degrade or skip due
+// to required system features being denied or unavailable.
+const CanDegrade = true

internal/info/optional_strict.go

@@ -0,0 +1,5 @@
+//go:build noskip
+
+package info
+
+const CanDegrade = false

internal/kobject/event.go

@@ -0,0 +1,90 @@
+package kobject
+
+import (
+	"errors"
+	"strconv"
+	"strings"
+	"unsafe"
+
+	"hakurei.app/internal/uevent"
+)
+
+// Event is a [uevent.Message] with known environment variables processed.
+type Event struct {
+	// alloc_uevent_skb: action_string
+	Action uevent.KobjectAction `json:"action"`
+	// alloc_uevent_skb: devpath
+	DevPath string `json:"devpath"`
+
+	// Uninterpreted environment variable pairs. An entry missing a separator
+	// gains the value "\x00".
+	Env map[string]string `json:"env"`
+
+	// SEQNUM value set by the kernel.
+	Sequence uint64 `json:"seqnum"`
+	// SYNTH_UUID value set on trigger, nil denotes a non-synthetic event.
+	Synth *uevent.UUID `json:"synth_uuid,omitempty"`
+	// SUBSYSTEM value set by the kernel.
+	Subsystem string `json:"subsystem"`
+}
+
+// Populate populates e with the contents of a [uevent.Message].
+//
+// The ACTION and DEVPATH environment variables are ignored and assumed to be
+// consistent with the header.
+func (e *Event) Populate(reportErr func(error), m *uevent.Message) {
+	if reportErr == nil {
+		reportErr = func(error) {}
+	}
+
+	*e = Event{
+		Action:  m.Action,
+		DevPath: m.DevPath,
+		Env:     make(map[string]string),
+	}
+
+	for _, s := range m.Env {
+		k, v, ok := strings.Cut(s, "=")
+		if !ok {
+			if _, ok = e.Env[s]; !ok {
+				e.Env[s] = "\x00"
+			}
+			continue
+		}
+
+		switch k {
+		case "ACTION", "DEVPATH":
+			continue
+
+		case "SEQNUM":
+			seq, err := strconv.ParseUint(v, 10, 64)
+			if err != nil {
+				if _e := errors.Unwrap(err); _e != nil {
+					err = _e
+				}
+				reportErr(err)
+
+				e.Env[k] = v
+				continue
+			}
+			e.Sequence = seq
+
+		case "SYNTH_UUID":
+			var uuid uevent.UUID
+			err := uuid.UnmarshalText(unsafe.Slice(unsafe.StringData(v), len(v)))
+			if err != nil {
+				reportErr(err)
+
+				e.Env[k] = v
+				continue
+			}
+			e.Synth = &uuid
+
+		case "SUBSYSTEM":
+			e.Subsystem = v
+
+		default:
+			e.Env[k] = v
+		}
+	}
+}

internal/kobject/event_test.go

@@ -0,0 +1,92 @@
+package kobject_test
+
+import (
+	"reflect"
+	"strconv"
+	"testing"
+
+	"hakurei.app/internal/kobject"
+	"hakurei.app/internal/uevent"
+)
+
+func TestEvent(t *testing.T) {
+	t.Parallel()
+
+	testCases := []struct {
+		name string
+		msg  uevent.Message
+		want kobject.Event
+		errs []error
+	}{
+		{"sample coldboot qemu", uevent.Message{
+			Action:  uevent.KOBJ_ADD,
+			DevPath: "/devices/LNXSYSTM:00/LNXPWRBN:00",
+			Env: []string{
+				"ACTION=add",
+				"DEVPATH=/devices/LNXSYSTM:00/LNXPWRBN:00",
+				"SUBSYSTEM=acpi",
+				"SYNTH_UUID=fe4d7c9d-b8c6-4a70-9ef1-3d8a58d18eed",
+				"MODALIAS=acpi:LNXPWRBN:",
+				"SEQNUM=777",
+			}}, kobject.Event{
+			Action:  uevent.KOBJ_ADD,
+			DevPath: "/devices/LNXSYSTM:00/LNXPWRBN:00",
+			Env: map[string]string{
+				"MODALIAS": "acpi:LNXPWRBN:",
+			},
+			Sequence: 777,
+			Synth: &uevent.UUID{
+				0xfe, 0x4d, 0x7c, 0x9d,
+				0xb8, 0xc6,
+				0x4a, 0x70,
+				0x9e, 0xf1,
+				0x3d, 0x8a, 0x58, 0xd1, 0x8e, 0xed,
+			},
+			Subsystem: "acpi",
+		}, []error{}},
+
+		{"nil reportErr", uevent.Message{Env: []string{
+			"SEQNUM=\x00",
+		}}, kobject.Event{Env: map[string]string{
+			"SEQNUM": "\x00",
+		}}, nil},
+
+		{"bad SEQNUM SYNTH_UUID", uevent.Message{Env: []string{
+			"SEQNUM=\x00",
+			"SYNTH_UUID=\x00",
+			"SUBSYSTEM=\x00",
+		}}, kobject.Event{Subsystem: "\x00", Env: map[string]string{
+			"SEQNUM":     "\x00",
+			"SYNTH_UUID": "\x00",
+		}}, []error{strconv.ErrSyntax, uevent.UUIDSizeError(1)}},
+
+		{"bad sep", uevent.Message{Env: []string{
+			"SYNTH_UUID",
+		}}, kobject.Event{Env: map[string]string{
+			"SYNTH_UUID": "\x00",
+		}}, []error{}},
+	}
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			t.Parallel()
+
+			var f func(error)
+			gotErrs := make([]error, 0)
+			if tc.errs != nil {
+				f = func(err error) {
+					gotErrs = append(gotErrs, err)
+				}
+			}
+
+			var got kobject.Event
+			got.Populate(f, &tc.msg)
+
+			if !reflect.DeepEqual(&got, &tc.want) {
+				t.Errorf("Populate: %#v, want %#v", got, tc.want)
+			}
+			if tc.errs != nil && !reflect.DeepEqual(gotErrs, tc.errs) {
+				t.Errorf("Populate: errs = %v, want %v", gotErrs, tc.errs)
+			}
+		})
+	}
+}

internal/netlink/netlink.go

@@ -2,29 +2,32 @@
 package netlink
 
 import (
+	"context"
 	"fmt"
 	"os"
-	"sync"
 	"syscall"
+	"time"
 	"unsafe"
 )
 
-// AF_NETLINK socket is never shared
-var (
-	nlPid     uint32
-	nlPidOnce sync.Once
+// net/netlink/af_netlink.c
+const maxRecvmsgLen = 32768
+
+const (
+	// stateOpen denotes an open conn.
+	stateOpen uint32 = 1 << iota
 )
 
-// getpid returns a cached pid value.
-func getpid() uint32 {
-	nlPidOnce.Do(func() { nlPid = uint32(os.Getpid()) })
-	return nlPid
-}
-
-// A conn represents resources associated to a netlink socket.
-type conn struct {
+// A Conn represents resources associated to a netlink socket.
+type Conn struct {
 	// AF_NETLINK socket.
-	fd int
+	f *os.File
+	// For using runtime polling via f.
+	raw syscall.RawConn
+	// Port ID assigned by the kernel.
+	port uint32
+	// Internal connection status.
+	state uint32
 	// Kernel module or netlink group to communicate with.
 	family int
 	// Message sequence number.
@@ -33,40 +36,193 @@ type conn struct {
 	typ, flags uint16
 	// Outgoing position in buf.
 	pos int
-	// A page holding incoming and outgoing messages.
-	buf []byte
+	// Pages holding incoming and outgoing messages.
+	buf [maxRecvmsgLen]byte
+	// An instant some time after conn was established, but before the first
+	// I/O operation on f through raw. This serves as a cached deadline to
+	// cancel blocking I/O.
+	t time.Time
 }
 
-// dial returns the address of a newly connected conn of specified family.
-func dial(family int) (*conn, error) {
-	var c conn
+// Dial returns the address of a newly connected generic netlink connection of
+// specified family and groups.
+//
+// For a nonzero rcvbuf, the socket receive buffer size is set to its absolute
+// value via SO_RCVBUF for a positive value, or SO_RCVBUFFORCE for a negative
+// value.
+func Dial(family int, groups uint32, rcvbuf int64) (*Conn, error) {
+	var c Conn
 	if fd, err := syscall.Socket(
 		syscall.AF_NETLINK,
-		syscall.SOCK_RAW|syscall.SOCK_CLOEXEC,
+		syscall.SOCK_RAW|syscall.SOCK_NONBLOCK|syscall.SOCK_CLOEXEC,
 		family,
 	); err != nil {
 		return nil, os.NewSyscallError("socket", err)
 	} else if err = syscall.Bind(fd, &syscall.SockaddrNetlink{
 		Family: syscall.AF_NETLINK,
-		Pid:    getpid(),
+		Groups: groups,
 	}); err != nil {
 		_ = syscall.Close(fd)
 		return nil, os.NewSyscallError("bind", err)
 	} else {
-		c.fd, c.family = fd, family
+		var addr syscall.Sockaddr
+		if addr, err = syscall.Getsockname(fd); err != nil {
+			_ = syscall.Close(fd)
+			return nil, os.NewSyscallError("getsockname", err)
+		}
+		switch a := addr.(type) {
+		case *syscall.SockaddrNetlink:
+			c.port = a.Pid
+
+		default: // unreachable
+			_ = syscall.Close(fd)
+			return nil, syscall.ENOTRECOVERABLE
+		}
+
+		if rcvbuf != 0 {
+			opt := syscall.SO_RCVBUF
+			if rcvbuf < 0 {
+				opt = syscall.SO_RCVBUFFORCE
+				rcvbuf = -rcvbuf
+			}
+			if err = syscall.SetsockoptInt(
+				fd,
+				syscall.SOL_SOCKET,
+				opt,
+				int(rcvbuf),
+			); err != nil {
+				_ = syscall.Close(fd)
+				return nil, os.NewSyscallError("setsockopt", err)
+			}
+		}
+
+		c.family = family
+		c.f = os.NewFile(uintptr(fd), "netlink")
+		if c.raw, err = c.f.SyscallConn(); err != nil {
+			_ = c.f.Close()
+			return nil, err
+		}
+		c.state |= stateOpen
 	}
+
 	c.pos = syscall.NLMSG_HDRLEN
-	c.buf = make([]byte, os.Getpagesize())
+	c.t = time.Now().UTC()
 	return &c, nil
 }
 
+// ok returns whether conn is still open.
+func (c *Conn) ok() bool { return c.state&stateOpen != 0 }
+
 // Close closes the underlying socket.
-func (c *conn) Close() error {
-	if c.buf == nil {
+func (c *Conn) Close() error {
+	if !c.ok() {
 		return syscall.EINVAL
 	}
-	c.buf = nil
-	return syscall.Close(c.fd)
+	c.state &= ^stateOpen
+	return c.f.Close()
+}
+
+// Recvmsg wraps recv(2) with nonblocking behaviour via the runtime network poller.
+//
+// The returned slice is valid until the next call to Recvmsg.
+func (c *Conn) Recvmsg(
+	ctx context.Context,
+	flags int,
+) (data []byte, recvflags int, from syscall.Sockaddr, err error) {
+	if err = c.f.SetReadDeadline(time.Time{}); err != nil {
+		return
+	}
+
+	var n int
+	data = c.buf[:]
+
+	if ctx == nil {
+		rcErr := c.raw.Control(func(fd uintptr) {
+			n, _, recvflags, from, err = syscall.Recvmsg(int(fd), data, nil, flags)
+		})
+		if n >= 0 {
+			data = data[:n]
+		}
+
+		if err != nil {
+			err = os.NewSyscallError("recvmsg", err)
+		} else {
+			err = rcErr
+		}
+		return
+	}
+
+	done := make(chan error, 1)
+	go func() {
+		rcErr := c.raw.Read(func(fd uintptr) (done bool) {
+			n, _, recvflags, from, err = syscall.Recvmsg(int(fd), data, nil, flags)
+			return err != syscall.EWOULDBLOCK
+		})
+		if n >= 0 {
+			data = data[:n]
+		}
+		done <- rcErr
+	}()
+
+	select {
+	case rcErr := <-done:
+		if err != nil {
+			err = os.NewSyscallError("recvmsg", err)
+		} else {
+			err = rcErr
+		}
+		return
+
+	case <-ctx.Done():
+		cancelErr := c.f.SetReadDeadline(c.t)
+		<-done
+		if cancelErr != nil {
+			err = cancelErr
+		} else {
+			err = ctx.Err()
+		}
+		return
+	}
+}
+
+// Sendmsg wraps send(2) with nonblocking behaviour via the runtime network poller.
+func (c *Conn) Sendmsg(
+	ctx context.Context,
+	p []byte,
+	to syscall.Sockaddr,
+	flags int,
+) (err error) {
+	if err = c.f.SetWriteDeadline(time.Time{}); err != nil {
+		return
+	}
+
+	done := make(chan error, 1)
+	go func() {
+		done <- c.raw.Write(func(fd uintptr) (done bool) {
+			err = syscall.Sendmsg(int(fd), p, nil, to, flags)
+			return err != syscall.EWOULDBLOCK
+		})
+	}()
+
+	select {
+	case rcErr := <-done:
+		if err != nil {
+			err = os.NewSyscallError("sendmsg", err)
+		} else {
+			err = rcErr
+		}
+		return
+
+	case <-ctx.Done():
+		cancelErr := c.f.SetWriteDeadline(c.t)
+		<-done
+		if cancelErr != nil {
+			err = cancelErr
+		} else {
+			err = ctx.Err()
+		}
+		return
+	}
 }
 
 // Msg is type constraint for types sent over the wire via netlink.
@@ -88,7 +244,7 @@ func As[M Msg](data []byte) *M {
 }
 
 // add queues a value to be sent by conn.
-func add[M Msg](c *conn, p *M) bool {
+func add[M Msg](c *Conn, p *M) bool {
 	pos := c.pos
 	c.pos += int(unsafe.Sizeof(*p))
 	if c.pos > len(c.buf) {
@@ -122,8 +278,16 @@ func (e *InconsistentError) Error() string {
 	return s
 }
 
+// checkReply checks the message header of a reply from the kernel.
+func (c *Conn) checkReply(header *syscall.NlMsghdr) error {
+	if header.Seq != c.seq || header.Pid != c.port {
+		return &InconsistentError{*header, c.seq, c.port}
+	}
+	return nil
+}
+
 // pending returns the valid slice of buf and initialises pos.
-func (c *conn) pending() []byte {
+func (c *Conn) pending() []byte {
 	buf := c.buf[:c.pos]
 	c.pos = syscall.NLMSG_HDRLEN
 
@@ -132,7 +296,7 @@ func (c *conn) pending() []byte {
 		Type:  c.typ,
 		Flags: c.flags,
 		Seq:   c.seq,
-		Pid:   getpid(),
+		Pid:   c.port,
 	}
 	return buf
 }
@@ -143,44 +307,44 @@ type Complete struct{}
 // Error returns a hardcoded string that should never be displayed to the user.
 func (Complete) Error() string { return "returning from roundtrip" }
 
+// HandlerFunc handles [syscall.NetlinkMessage] and returns a non-nil error to
+// discontinue the receiving of more messages.
+type HandlerFunc func(resp []syscall.NetlinkMessage) error
+
+// receive receives from a socket with specified flags until a non-nil error is
+// returned by f. An error of type [Complete] is returned as nil.
+func (c *Conn) receive(ctx context.Context, f HandlerFunc, flags int) error {
+	for {
+		var resp []syscall.NetlinkMessage
+		if data, _, _, err := c.Recvmsg(ctx, flags); err != nil {
+			return err
+		} else if len(data) < syscall.NLMSG_HDRLEN {
+			return syscall.EBADE
+		} else if resp, err = syscall.ParseNetlinkMessage(data); err != nil {
+			return err
+		}
+
+		if err := f(resp); err != nil {
+			if err == (Complete{}) {
+				return nil
+			}
+			return err
+		}
+	}
+}
+
 // Roundtrip sends the pending message and handles the reply.
-func (c *conn) Roundtrip(f func(msg *syscall.NetlinkMessage) error) error {
-	if c.buf == nil {
+func (c *Conn) Roundtrip(ctx context.Context, f HandlerFunc) error {
+	if !c.ok() {
 		return syscall.EINVAL
 	}
 	defer func() { c.seq++ }()
 
-	if err := syscall.Sendto(c.fd, c.pending(), 0, &syscall.SockaddrNetlink{
+	if err := c.Sendmsg(ctx, c.pending(), &syscall.SockaddrNetlink{
 		Family: syscall.AF_NETLINK,
-	}); err != nil {
-		return os.NewSyscallError("sendto", err)
+	}, 0); err != nil {
+		return err
 	}
 
-	for {
-		buf := c.buf
-		if n, _, err := syscall.Recvfrom(c.fd, buf, 0); err != nil {
-			return os.NewSyscallError("recvfrom", err)
-		} else if n < syscall.NLMSG_HDRLEN {
-			return syscall.EBADE
-		} else {
-			buf = buf[:n]
-		}
-
-		msgs, err := syscall.ParseNetlinkMessage(buf)
-		if err != nil {
-			return err
-		}
-
-		for _, msg := range msgs {
-			if msg.Header.Seq != c.seq || msg.Header.Pid != getpid() {
-				return &InconsistentError{msg.Header, c.seq, getpid()}
-			}
-			if err = f(&msg); err != nil {
-				if err == (Complete{}) {
-					return nil
-				}
-				return err
-			}
-		}
-	}
+	return c.receive(ctx, f, 0)
 }

internal/netlink/netlink_test.go

@@ -1,16 +1,13 @@
 package netlink
 
 import (
-	"os"
 	"syscall"
 	"testing"
 )
 
-func init() { nlPidOnce.Do(func() {}); nlPid = 1 }
-
 type payloadTestCase struct {
 	name string
-	f    func(c *conn)
+	f    func(c *Conn)
 	want []byte
 }
 
@@ -22,11 +19,9 @@ func checkPayload(t *testing.T, testCases []payloadTestCase) {
 	for _, tc := range testCases {
 		t.Run(tc.name, func(t *testing.T) {
 			t.Parallel()
+			t.Helper()
 
-			c := conn{
-				pos: syscall.NLMSG_HDRLEN,
-				buf: make([]byte, os.Getpagesize()),
-			}
+			c := Conn{port: 1, pos: syscall.NLMSG_HDRLEN}
 			tc.f(&c)
 			if got := c.pending(); string(got) != string(tc.want) {
 				t.Errorf("pending: %#v, want %#v", got, tc.want)

internal/netlink/rtnl.go

@@ -1,16 +1,20 @@
 package netlink
 
 import (
+	"context"
 	"syscall"
 	"unsafe"
 )
 
 // RouteConn represents a NETLINK_ROUTE socket.
-type RouteConn struct{ *conn }
+type RouteConn struct{ conn *Conn }
+
+// Close closes the underlying socket.
+func (c *RouteConn) Close() error { return c.conn.Close() }
 
 // DialRoute returns the address of a newly connected [RouteConn].
-func DialRoute() (*RouteConn, error) {
-	c, err := dial(syscall.NETLINK_ROUTE)
+func DialRoute(rcvbuf int64) (*RouteConn, error) {
+	c, err := Dial(syscall.NETLINK_ROUTE, 0, rcvbuf)
 	if err != nil {
 		return nil, err
 	}
@@ -18,23 +22,27 @@ func DialRoute() (*RouteConn, error) {
 }
 
 // rtnlConsume consumes a message from rtnetlink.
-func rtnlConsume(msg *syscall.NetlinkMessage) error {
-	switch msg.Header.Type {
-	case syscall.NLMSG_DONE:
-		return Complete{}
-
-	case syscall.NLMSG_ERROR:
-		if e := As[syscall.NlMsgerr](msg.Data); e != nil {
-			if e.Error == 0 {
-				return Complete{}
-			}
-			return syscall.Errno(-e.Error)
+func (c *RouteConn) rtnlConsume(resp []syscall.NetlinkMessage) error {
+	for i := range resp {
+		if err := c.conn.checkReply(&resp[i].Header); err != nil {
+			return err
 		}
-		return syscall.EBADE
 
-	default:
-		return nil
+		switch resp[i].Header.Type {
+		case syscall.NLMSG_DONE:
+			return Complete{}
+
+		case syscall.NLMSG_ERROR:
+			if e := As[syscall.NlMsgerr](resp[i].Data); e != nil {
+				if e.Error == 0 {
+					return Complete{}
+				}
+				return syscall.Errno(-e.Error)
+			}
+			return syscall.EBADE
+		}
 	}
+	return nil
 }
 
 // InAddr is equivalent to struct in_addr.
@@ -57,7 +65,7 @@ func (c *RouteConn) writeIfAddrmsg(
 	msg *syscall.IfAddrmsg,
 	attrs ...RtAttrMsg[InAddr],
 ) bool {
-	c.typ, c.flags = typ, syscall.NLM_F_REQUEST|syscall.NLM_F_ACK|flags
+	c.conn.typ, c.conn.flags = typ, syscall.NLM_F_REQUEST|syscall.NLM_F_ACK|flags
 	if !add(c.conn, msg) {
 		return false
 	}
@@ -72,6 +80,7 @@ func (c *RouteConn) writeIfAddrmsg(
 
 // SendIfAddrmsg sends an ifaddrmsg structure to rtnetlink.
 func (c *RouteConn) SendIfAddrmsg(
+	ctx context.Context,
 	typ, flags uint16,
 	msg *syscall.IfAddrmsg,
 	attrs ...RtAttrMsg[InAddr],
@@ -79,7 +88,7 @@ func (c *RouteConn) SendIfAddrmsg(
 	if !c.writeIfAddrmsg(typ, flags, msg, attrs...) {
 		return syscall.ENOMEM
 	}
-	return c.Roundtrip(rtnlConsume)
+	return c.conn.Roundtrip(ctx, c.rtnlConsume)
 }
 
 // writeNewaddrLo writes a RTM_NEWADDR message for the loopback address.
@@ -104,11 +113,11 @@ func (c *RouteConn) writeNewaddrLo(lo uint32) bool {
 }
 
 // SendNewaddrLo sends a RTM_NEWADDR message for the loopback address to the kernel.
-func (c *RouteConn) SendNewaddrLo(lo uint32) error {
+func (c *RouteConn) SendNewaddrLo(ctx context.Context, lo uint32) error {
 	if !c.writeNewaddrLo(lo) {
 		return syscall.ENOMEM
 	}
-	return c.Roundtrip(rtnlConsume)
+	return c.conn.Roundtrip(ctx, c.rtnlConsume)
 }
 
 // writeIfInfomsg writes an ifinfomsg structure to conn.
@@ -116,17 +125,18 @@ func (c *RouteConn) writeIfInfomsg(
 	typ, flags uint16,
 	msg *syscall.IfInfomsg,
 ) bool {
-	c.typ, c.flags = typ, syscall.NLM_F_REQUEST|syscall.NLM_F_ACK|flags
+	c.conn.typ, c.conn.flags = typ, syscall.NLM_F_REQUEST|syscall.NLM_F_ACK|flags
 	return add(c.conn, msg)
 }
 
 // SendIfInfomsg sends an ifinfomsg structure to rtnetlink.
 func (c *RouteConn) SendIfInfomsg(
+	ctx context.Context,
 	typ, flags uint16,
 	msg *syscall.IfInfomsg,
 ) error {
 	if !c.writeIfInfomsg(typ, flags, msg) {
 		return syscall.ENOMEM
 	}
-	return c.Roundtrip(rtnlConsume)
+	return c.conn.Roundtrip(ctx, c.rtnlConsume)
 }

internal/netlink/rtnl_test.go

@@ -9,7 +9,7 @@ func TestPayloadRTNETLINK(t *testing.T) {
 	t.Parallel()
 
 	checkPayload(t, []payloadTestCase{
-		{"RTM_NEWADDR lo", func(c *conn) {
+		{"RTM_NEWADDR lo", func(c *Conn) {
 			(&RouteConn{c}).writeNewaddrLo(1)
 		}, []byte{
 			/* Len   */ 0x28, 0, 0, 0,
@@ -33,7 +33,7 @@ func TestPayloadRTNETLINK(t *testing.T) {
 			/* in_addr */ 127, 0, 0, 1,
 		}},
 
-		{"RTM_NEWLINK", func(c *conn) {
+		{"RTM_NEWLINK", func(c *Conn) {
 			c.seq++
 			(&RouteConn{c}).writeIfInfomsg(
 				syscall.RTM_NEWLINK, 0,

internal/outcome/dispatcher.go

@@ -17,6 +17,7 @@ import (
 	"hakurei.app/ext"
 	"hakurei.app/internal/dbus"
 	"hakurei.app/internal/info"
+	"hakurei.app/internal/params"
 	"hakurei.app/message"
 )
 
@@ -84,7 +85,7 @@ type syscallDispatcher interface {
 	// setDumpable provides [container.SetDumpable].
 	setDumpable(dumpable uintptr) error
 	// receive provides [container.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)
 
 	// containerStart provides the Start method of [container.Container].
 	containerStart(z *container.Container) error
@@ -154,8 +155,8 @@ func (direct) prctl(op, arg2, arg3 uintptr) error { return ext.Prctl(op, arg2, a
 func (direct) overflowUid(msg message.Msg) int    { return container.OverflowUid(msg) }
 func (direct) overflowGid(msg message.Msg) int    { return container.OverflowGid(msg) }
 func (direct) setDumpable(dumpable uintptr) error { return ext.SetDumpable(dumpable) }
-func (direct) receive(key string, e any, fdp *uintptr) (func() error, error) {
-	return container.Receive(key, e, fdp)
+func (direct) receive(key string, e any, fdp *int) (func() error, error) {
+	return params.Receive(key, e, fdp)
 }
 
 func (direct) containerStart(z *container.Container) error { return z.Start() }

internal/outcome/dispatcher_test.go

@@ -401,12 +401,12 @@ func (k *kstub) setDumpable(dumpable uintptr) error {
 		stub.CheckArg(k.Stub, "dumpable", dumpable, 0))
 }
 
-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")
 	reflect.ValueOf(e).Elem().Set(reflect.ValueOf(expect.Args[1]))
 	if expect.Args[2] != nil {
-		*fdp = expect.Args[2].(uintptr)
+		*fdp = int(expect.Args[2].(uintptr))
 	}
 	return func() error { return k.Expects("closeReceive").Err }, expect.Error(
 		stub.CheckArg(k.Stub, "key", key, 0))
@@ -690,38 +690,38 @@ func (panicMsgContext) Value(any) any               { panic("unreachable") }
 // This type is meant to be embedded in partial syscallDispatcher implementations.
 type panicDispatcher struct{}
 
-func (panicDispatcher) new(func(k syscallDispatcher, msg message.Msg))      { panic("unreachable") }
-func (panicDispatcher) getppid() int                                        { panic("unreachable") }
-func (panicDispatcher) getpid() int                                         { panic("unreachable") }
-func (panicDispatcher) getuid() int                                         { panic("unreachable") }
-func (panicDispatcher) getgid() int                                         { panic("unreachable") }
-func (panicDispatcher) lookupEnv(string) (string, bool)                     { panic("unreachable") }
-func (panicDispatcher) pipe() (*os.File, *os.File, error)                   { panic("unreachable") }
-func (panicDispatcher) stat(string) (os.FileInfo, error)                    { panic("unreachable") }
-func (panicDispatcher) open(string) (osFile, error)                         { panic("unreachable") }
-func (panicDispatcher) readdir(string) ([]os.DirEntry, error)               { panic("unreachable") }
-func (panicDispatcher) tempdir() string                                     { panic("unreachable") }
-func (panicDispatcher) mkdir(string, os.FileMode) error                     { panic("unreachable") }
-func (panicDispatcher) removeAll(string) error                              { panic("unreachable") }
-func (panicDispatcher) exit(int)                                            { panic("unreachable") }
-func (panicDispatcher) evalSymlinks(string) (string, error)                 { panic("unreachable") }
-func (panicDispatcher) prctl(uintptr, uintptr, uintptr) error               { panic("unreachable") }
-func (panicDispatcher) lookupGroupId(string) (string, error)                { panic("unreachable") }
-func (panicDispatcher) lookPath(string) (string, error)                     { panic("unreachable") }
-func (panicDispatcher) cmdOutput(*exec.Cmd) ([]byte, error)                 { panic("unreachable") }
-func (panicDispatcher) overflowUid(message.Msg) int                         { panic("unreachable") }
-func (panicDispatcher) overflowGid(message.Msg) int                         { panic("unreachable") }
-func (panicDispatcher) setDumpable(uintptr) error                           { panic("unreachable") }
-func (panicDispatcher) receive(string, any, *uintptr) (func() error, error) { panic("unreachable") }
-func (panicDispatcher) containerStart(*container.Container) error           { panic("unreachable") }
-func (panicDispatcher) containerServe(*container.Container) error           { panic("unreachable") }
-func (panicDispatcher) containerWait(*container.Container) error            { panic("unreachable") }
-func (panicDispatcher) mustHsuPath() *check.Absolute                        { panic("unreachable") }
-func (panicDispatcher) dbusAddress() (string, string)                       { panic("unreachable") }
-func (panicDispatcher) setupContSignal(int) (io.ReadCloser, func(), error)  { panic("unreachable") }
-func (panicDispatcher) getMsg() message.Msg                                 { panic("unreachable") }
-func (panicDispatcher) fatal(...any)                                        { panic("unreachable") }
-func (panicDispatcher) fatalf(string, ...any)                               { panic("unreachable") }
+func (panicDispatcher) new(func(k syscallDispatcher, msg message.Msg))     { panic("unreachable") }
+func (panicDispatcher) getppid() int                                       { panic("unreachable") }
+func (panicDispatcher) getpid() int                                        { panic("unreachable") }
+func (panicDispatcher) getuid() int                                        { panic("unreachable") }
+func (panicDispatcher) getgid() int                                        { panic("unreachable") }
+func (panicDispatcher) lookupEnv(string) (string, bool)                    { panic("unreachable") }
+func (panicDispatcher) pipe() (*os.File, *os.File, error)                  { panic("unreachable") }
+func (panicDispatcher) stat(string) (os.FileInfo, error)                   { panic("unreachable") }
+func (panicDispatcher) open(string) (osFile, error)                        { panic("unreachable") }
+func (panicDispatcher) readdir(string) ([]os.DirEntry, error)              { panic("unreachable") }
+func (panicDispatcher) tempdir() string                                    { panic("unreachable") }
+func (panicDispatcher) mkdir(string, os.FileMode) error                    { panic("unreachable") }
+func (panicDispatcher) removeAll(string) error                             { panic("unreachable") }
+func (panicDispatcher) exit(int)                                           { panic("unreachable") }
+func (panicDispatcher) evalSymlinks(string) (string, error)                { panic("unreachable") }
+func (panicDispatcher) prctl(uintptr, uintptr, uintptr) error              { panic("unreachable") }
+func (panicDispatcher) lookupGroupId(string) (string, error)               { panic("unreachable") }
+func (panicDispatcher) lookPath(string) (string, error)                    { panic("unreachable") }
+func (panicDispatcher) cmdOutput(*exec.Cmd) ([]byte, error)                { panic("unreachable") }
+func (panicDispatcher) overflowUid(message.Msg) int                        { panic("unreachable") }
+func (panicDispatcher) overflowGid(message.Msg) int                        { panic("unreachable") }
+func (panicDispatcher) setDumpable(uintptr) error                          { panic("unreachable") }
+func (panicDispatcher) receive(string, any, *int) (func() error, error)    { panic("unreachable") }
+func (panicDispatcher) containerStart(*container.Container) error          { panic("unreachable") }
+func (panicDispatcher) containerServe(*container.Container) error          { panic("unreachable") }
+func (panicDispatcher) containerWait(*container.Container) error           { panic("unreachable") }
+func (panicDispatcher) mustHsuPath() *check.Absolute                       { panic("unreachable") }
+func (panicDispatcher) dbusAddress() (string, string)                      { panic("unreachable") }
+func (panicDispatcher) setupContSignal(int) (io.ReadCloser, func(), error) { panic("unreachable") }
+func (panicDispatcher) getMsg() message.Msg                                { panic("unreachable") }
+func (panicDispatcher) fatal(...any)                                       { panic("unreachable") }
+func (panicDispatcher) fatalf(string, ...any)                              { panic("unreachable") }
 
 func (panicDispatcher) notifyContext(context.Context, ...os.Signal) (context.Context, context.CancelFunc) {
 	panic("unreachable")

internal/outcome/process.go

@@ -13,7 +13,6 @@ import (
 	"time"
 
 	"hakurei.app/check"
-	"hakurei.app/container"
 	"hakurei.app/fhs"
 	"hakurei.app/hst"
 	"hakurei.app/internal/info"
@@ -372,17 +371,18 @@ func (k *outcome) start(ctx context.Context, msg message.Msg,
 	// shim runs in the same session as monitor; see shim.go for behaviour
 	cmd.Cancel = func() error { return cmd.Process.Signal(syscall.SIGCONT) }
 
-	var shimPipe *os.File
-	if fd, w, err := container.Setup(&cmd.ExtraFiles); err != nil {
+	var shimPipe [2]*os.File
+	if r, w, err := os.Pipe(); err != nil {
 		return cmd, nil, &hst.AppError{Step: "create shim setup pipe", Err: err}
 	} else {
-		shimPipe = w
 		cmd.Env = []string{
 			// passed through to shim by hsu
-			shimEnv + "=" + strconv.Itoa(fd),
+			shimEnv + "=" + strconv.Itoa(3+len(cmd.ExtraFiles)),
 			// interpreted by hsu
 			"HAKUREI_IDENTITY=" + k.state.identity.String(),
 		}
+		cmd.ExtraFiles = append(cmd.ExtraFiles, r)
+		shimPipe[0], shimPipe[1] = r, w
 	}
 
 	if len(k.supp) > 0 {
@@ -393,12 +393,16 @@ func (k *outcome) start(ctx context.Context, msg message.Msg,
 
 	msg.Verbosef("setuid helper at %s", hsuPath)
 	if err := cmd.Start(); err != nil {
+		_, _ = shimPipe[0].Close(), shimPipe[1].Close()
 		msg.Resume()
-		return cmd, shimPipe, &hst.AppError{Step: "start setuid wrapper", Err: err}
+		return cmd, nil, &hst.AppError{Step: "start setuid wrapper", Err: err}
+	}
+	if err := shimPipe[0].Close(); err != nil {
+		msg.Verbose(err)
 	}
 
 	*startTime = time.Now().UTC()
-	return cmd, shimPipe, nil
+	return cmd, shimPipe[1], nil
 }
 
 // serveShim serves outcomeState through the shim setup pipe.
@@ -411,11 +415,11 @@ func serveShim(msg message.Msg, shimPipe *os.File, state *outcomeState) error {
 		msg.Verbose(err.Error())
 	}
 	if err := gob.NewEncoder(shimPipe).Encode(state); err != nil {
+		_ = shimPipe.Close()
 		msg.Resume()
 		return &hst.AppError{Step: "transmit shim config", Err: err}
 	}
-	_ = shimPipe.Close()
-	return nil
+	return shimPipe.Close()
 }
 
 // printMessageError prints the error message according to [message.GetMessage],

internal/outcome/shim.go

@@ -20,6 +20,7 @@ import (
 	"hakurei.app/ext"
 	"hakurei.app/fhs"
 	"hakurei.app/hst"
+	"hakurei.app/internal/params"
 	"hakurei.app/internal/pipewire"
 	"hakurei.app/message"
 )
@@ -197,7 +198,7 @@ func shimEntrypoint(k syscallDispatcher) {
 		if errors.Is(err, syscall.EBADF) {
 			k.fatal("invalid config descriptor")
 		}
-		if errors.Is(err, container.ErrReceiveEnv) {
+		if errors.Is(err, params.ErrReceiveEnv) {
 			k.fatal(shimEnv + " not set")
 		}
 

internal/outcome/shim_test.go

@@ -16,6 +16,7 @@ import (
 	"hakurei.app/fhs"
 	"hakurei.app/hst"
 	"hakurei.app/internal/env"
+	"hakurei.app/internal/params"
 	"hakurei.app/internal/stub"
 )
 
@@ -172,7 +173,7 @@ func TestShimEntrypoint(t *testing.T) {
 			call("setDumpable", stub.ExpectArgs{uintptr(ext.SUID_DUMP_DISABLE)}, nil, nil),
 			call("getppid", stub.ExpectArgs{}, 0xbad, nil),
 			call("setupContSignal", stub.ExpectArgs{0xbad}, 0, nil),
-			call("receive", stub.ExpectArgs{"HAKUREI_SHIM", outcomeState{}, nil}, nil, container.ErrReceiveEnv),
+			call("receive", stub.ExpectArgs{"HAKUREI_SHIM", outcomeState{}, nil}, nil, params.ErrReceiveEnv),
 			call("fatal", stub.ExpectArgs{[]any{"HAKUREI_SHIM not set"}}, nil, nil),
 
 			// deferred

internal/outcome/spcontainer.go

@@ -5,7 +5,7 @@ import (
 	"errors"
 	"io/fs"
 	"os"
-	"path"
+	"path/filepath"
 	"slices"
 	"strconv"
 	"syscall"
@@ -165,9 +165,9 @@ func (s *spFilesystemOp) toSystem(state *outcomeStateSys) error {
 			}
 			for _, pair := range entry.Values {
 				if pair[0] == "path" {
-					if path.IsAbs(pair[1]) {
+					if filepath.IsAbs(pair[1]) {
 						// get parent dir of socket
-						dir := path.Dir(pair[1])
+						dir := filepath.Dir(pair[1])
 						if dir == "." || dir == fhs.Root {
 							state.msg.Verbosef("dbus socket %q is in an unusual location", pair[1])
 						}
@@ -290,7 +290,9 @@ func (s *spFilesystemOp) toContainer(state *outcomeStateParams) error {
 	if state.Container.Flags&hst.FDevice == 0 {
 		state.params.Remount(fhs.AbsDev, syscall.MS_RDONLY)
 	}
-	state.params.Remount(fhs.AbsRoot, syscall.MS_RDONLY)
+	if !state.as.NoRemountRoot {
+		state.params.Remount(fhs.AbsRoot, syscall.MS_RDONLY)
+	}
 
 	state.params.Env = make([]string, 0, len(state.env))
 	for key, value := range state.env {

internal/params/params.go

@@ -0,0 +1,42 @@
+// Package params provides helpers for receiving setup payload from parent.
+package params
+
+import (
+	"encoding/gob"
+	"errors"
+	"os"
+	"strconv"
+	"syscall"
+)
+
+// ErrReceiveEnv is returned by [Receive] if setup fd is not present in environment.
+var ErrReceiveEnv = errors.New("environment variable not set")
+
+// Receive retrieves setup fd from the environment and receives params.
+//
+// The file descriptor written to the value pointed to by fdp must not be passed
+// to any system calls. It is made available for ordering file descriptor only.
+func Receive(key string, v any, fdp *int) (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 {
+			if _err := errors.Unwrap(err); _err != nil {
+				err = _err
+			}
+			return nil, err
+		} else {
+			setup = os.NewFile(uintptr(fd), "setup")
+			if setup == nil {
+				return nil, syscall.EDOM
+			}
+			if fdp != nil {
+				*fdp = fd
+			}
+		}
+	}
+
+	return setup.Close, gob.NewDecoder(setup).Decode(v)
+}

internal/params/params_test.go

@@ -1,4 +1,4 @@
-package container_test
+package params_test
 
 import (
 	"encoding/gob"
@@ -9,7 +9,7 @@ import (
 	"syscall"
 	"testing"
 
-	"hakurei.app/container"
+	"hakurei.app/internal/params"
 )
 
 func TestSetupReceive(t *testing.T) {
@@ -30,8 +30,8 @@ func TestSetupReceive(t *testing.T) {
 			})
 		}
 
-		if _, err := container.Receive(key, nil, nil); !errors.Is(err, container.ErrReceiveEnv) {
-			t.Errorf("Receive: error = %v, want %v", err, container.ErrReceiveEnv)
+		if _, err := params.Receive(key, nil, nil); !errors.Is(err, params.ErrReceiveEnv) {
+			t.Errorf("Receive: error = %v, want %v", err, params.ErrReceiveEnv)
 		}
 	})
 
@@ -39,7 +39,7 @@ func TestSetupReceive(t *testing.T) {
 		const key = "TEST_ENV_FORMAT"
 		t.Setenv(key, "")
 
-		if _, err := container.Receive(key, nil, nil); !errors.Is(err, strconv.ErrSyntax) {
+		if _, err := params.Receive(key, nil, nil); !errors.Is(err, strconv.ErrSyntax) {
 			t.Errorf("Receive: error = %v, want %v", err, strconv.ErrSyntax)
 		}
 	})
@@ -48,7 +48,7 @@ func TestSetupReceive(t *testing.T) {
 		const key = "TEST_ENV_RANGE"
 		t.Setenv(key, "-1")
 
-		if _, err := container.Receive(key, nil, nil); !errors.Is(err, syscall.EDOM) {
+		if _, err := params.Receive(key, nil, nil); !errors.Is(err, syscall.EDOM) {
 			t.Errorf("Receive: error = %v, want %v", err, syscall.EDOM)
 		}
 	})
@@ -60,16 +60,22 @@ func TestSetupReceive(t *testing.T) {
 
 			encoderDone := make(chan error, 1)
 			extraFiles := make([]*os.File, 0, 1)
-			deadline, _ := t.Deadline()
-			if fd, f, err := container.Setup(&extraFiles); err != nil {
+			if r, w, err := os.Pipe(); err != nil {
 				t.Fatalf("Setup: error = %v", err)
-			} else if fd != 3 {
-				t.Fatalf("Setup: fd = %d, want 3", fd)
 			} else {
-				if err = f.SetDeadline(deadline); err != nil {
-					t.Fatal(err.Error())
+				t.Cleanup(func() {
+					if err = errors.Join(r.Close(), w.Close()); err != nil {
+						t.Fatal(err)
+					}
+				})
+
+				extraFiles = append(extraFiles, r)
+				if deadline, ok := t.Deadline(); ok {
+					if err = w.SetDeadline(deadline); err != nil {
+						t.Fatal(err)
+					}
 				}
-				go func() { encoderDone <- gob.NewEncoder(f).Encode(payload) }()
+				go func() { encoderDone <- gob.NewEncoder(w).Encode(payload) }()
 			}
 
 			if len(extraFiles) != 1 {
@@ -87,13 +93,13 @@ func TestSetupReceive(t *testing.T) {
 
 			var (
 				gotPayload []uint64
-				fdp        *uintptr
+				fdp        *int
 			)
 			if !useNilFdp {
-				fdp = new(uintptr)
+				fdp = new(int)
 			}
 			var closeFile func() error
-			if f, err := container.Receive(key, &gotPayload, fdp); err != nil {
+			if f, err := params.Receive(key, &gotPayload, fdp); err != nil {
 				t.Fatalf("Receive: error = %v", err)
 			} else {
 				closeFile = f
@@ -103,7 +109,7 @@ func TestSetupReceive(t *testing.T) {
 				}
 			}
 			if !useNilFdp {
-				if int(*fdp) != dupFd {
+				if *fdp != dupFd {
 					t.Errorf("Fd: %d, want %d", *fdp, dupFd)
 				}
 			}

internal/pipewire/pipewire.go

@@ -20,7 +20,7 @@ import (
 	"fmt"
 	"io"
 	"os"
-	"path"
+	"path/filepath"
 	"runtime"
 	"slices"
 	"strconv"
@@ -973,23 +973,23 @@ func connectName(name string, manager bool) (conn Conn, err error) {
 		return connectName(name+"-manager", false)
 	}
 
-	if path.IsAbs(name) || (len(name) > 0 && name[0] == '@') {
+	if filepath.IsAbs(name) || (len(name) > 0 && name[0] == '@') {
 		return Dial(name)
 	} else {
 		runtimeDir, ok := os.LookupEnv("PIPEWIRE_RUNTIME_DIR")
-		if !ok || !path.IsAbs(runtimeDir) {
+		if !ok || !filepath.IsAbs(runtimeDir) {
 			runtimeDir, ok = os.LookupEnv("XDG_RUNTIME_DIR")
 		}
-		if !ok || !path.IsAbs(runtimeDir) {
+		if !ok || !filepath.IsAbs(runtimeDir) {
 			// this is cargo culted from windows stuff and has no effect normally;
 			// keeping it to maintain compatibility in case someone sets this
 			runtimeDir, ok = os.LookupEnv("USERPROFILE")
 		}
 
-		if !ok || !path.IsAbs(runtimeDir) {
+		if !ok || !filepath.IsAbs(runtimeDir) {
 			runtimeDir = DEFAULT_SYSTEM_RUNTIME_DIR
 		}
-		return Dial(path.Join(runtimeDir, name))
+		return Dial(filepath.Join(runtimeDir, name))
 	}
 }
 

internal/pkg/dir_test.go

@@ -27,6 +27,31 @@ func TestFlatten(t *testing.T) {
 			fs.ModeCharDevice | 0400,
 		)},
 
+		{"coldboot", fstest.MapFS{
+			".": {Mode: fs.ModeDir | 0700},
+
+			"devices":        {Mode: fs.ModeDir | 0700},
+			"devices/uevent": {Mode: 0600, Data: []byte("add")},
+			"devices/empty":  {Mode: fs.ModeDir | 0700},
+
+			"devices/sub":        {Mode: fs.ModeDir | 0700},
+			"devices/sub/uevent": {Mode: 0600, Data: []byte("add")},
+
+			"block":        {Mode: fs.ModeDir | 0700},
+			"block/uevent": {Mode: 0600, Data: []byte{}},
+		}, []pkg.FlatEntry{
+			{Mode: fs.ModeDir | 0700, Path: "."},
+
+			{Mode: fs.ModeDir | 0700, Path: "block"},
+			{Mode: 0600, Path: "block/uevent", Data: []byte{}},
+
+			{Mode: fs.ModeDir | 0700, Path: "devices"},
+			{Mode: fs.ModeDir | 0700, Path: "devices/empty"},
+			{Mode: fs.ModeDir | 0700, Path: "devices/sub"},
+			{Mode: 0600, Path: "devices/sub/uevent", Data: []byte("add")},
+			{Mode: 0600, Path: "devices/uevent", Data: []byte("add")},
+		}, pkg.MustDecode("mEy_Lf5KotThm7OwMx7yTKZh5HCCyaB41pVAvI9uDMgVQFM91iosBLYsRm8bDsX8"), nil},
+
 		{"empty", fstest.MapFS{
 			".":          {Mode: fs.ModeDir | 0700},
 			"checksum":   {Mode: fs.ModeDir | 0700},
@@ -159,6 +184,32 @@ func TestFlatten(t *testing.T) {
 			{Mode: fs.ModeDir | 0700, Path: "work"},
 		}, pkg.MustDecode("WVpvsVqVKg9Nsh744x57h51AuWUoUR2nnh8Md-EYBQpk6ziyTuUn6PLtF2e0Eu_d"), nil},
 
+		{"sample no assume checksum", fstest.MapFS{
+			".": {Mode: fs.ModeDir | 0700},
+
+			"checksum": {Mode: fs.ModeDir | 0700},
+			"checksum/Aubi5EG4_Y8DhL9bQ3Q4HFBhLRF7X5gt9D3CNCQfT-TeBtlRXc7Zi_JYZEMoCC7M":       {Mode: fs.ModeDir | 0500},
+			"checksum/Aubi5EG4_Y8DhL9bQ3Q4HFBhLRF7X5gt9D3CNCQfT-TeBtlRXc7Zi_JYZEMoCC7M/check": {Mode: 0400, Data: []byte{}},
+
+			"identifier": {Mode: fs.ModeDir | 0700},
+			"identifier/_wAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA": {Mode: fs.ModeSymlink | 0777, Data: []byte("../checksum/Aubi5EG4_Y8DhL9bQ3Q4HFBhLRF7X5gt9D3CNCQfT-TeBtlRXc7Zi_JYZEMoCC7M")},
+			"identifier/_wEAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA": {Mode: fs.ModeSymlink | 0777, Data: []byte("../checksum/Aubi5EG4_Y8DhL9bQ3Q4HFBhLRF7X5gt9D3CNCQfT-TeBtlRXc7Zi_JYZEMoCC7M")},
+
+			"work": {Mode: fs.ModeDir | 0700},
+		}, []pkg.FlatEntry{
+			{Mode: fs.ModeDir | 0700, Path: "."},
+
+			{Mode: fs.ModeDir | 0700, Path: "checksum"},
+			{Mode: fs.ModeDir | 0500, Path: "checksum/Aubi5EG4_Y8DhL9bQ3Q4HFBhLRF7X5gt9D3CNCQfT-TeBtlRXc7Zi_JYZEMoCC7M"},
+			{Mode: 0400, Path: "checksum/Aubi5EG4_Y8DhL9bQ3Q4HFBhLRF7X5gt9D3CNCQfT-TeBtlRXc7Zi_JYZEMoCC7M/check", Data: []byte{}},
+
+			{Mode: fs.ModeDir | 0700, Path: "identifier"},
+			{Mode: fs.ModeSymlink | 0777, Path: "identifier/_wAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA", Data: []byte("../checksum/Aubi5EG4_Y8DhL9bQ3Q4HFBhLRF7X5gt9D3CNCQfT-TeBtlRXc7Zi_JYZEMoCC7M")},
+			{Mode: fs.ModeSymlink | 0777, Path: "identifier/_wEAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA", Data: []byte("../checksum/Aubi5EG4_Y8DhL9bQ3Q4HFBhLRF7X5gt9D3CNCQfT-TeBtlRXc7Zi_JYZEMoCC7M")},
+
+			{Mode: fs.ModeDir | 0700, Path: "work"},
+		}, pkg.MustDecode("OC290t23aimNo2Rp2pPwan5GI2KRLRdOwYxXQMD9jw0QROgHnNXWodoWdV0hwu2w"), nil},
+
 		{"sample tar step unpack", fstest.MapFS{
 			".": {Mode: fs.ModeDir | 0500},
 

internal/pkg/exec.go

@@ -8,7 +8,7 @@ import (
 	"io"
 	"os"
 	"os/exec"
-	"path"
+	"path/filepath"
 	"slices"
 	"strconv"
 	"syscall"
@@ -40,14 +40,14 @@ type ExecPath struct {
 	W bool
 }
 
-// SetSchedIdle is whether to set [std.SCHED_IDLE] scheduling priority.
-var SetSchedIdle bool
+// GetArtifactFunc is the function signature of [FContext.GetArtifact].
+type GetArtifactFunc func(Artifact) (*check.Absolute, unique.Handle[Checksum])
 
 // PromoteLayers returns artifacts with identical-by-content layers promoted to
 // the highest priority instance, as if mounted via [ExecPath].
 func PromoteLayers(
 	artifacts []Artifact,
-	getArtifact func(Artifact) (*check.Absolute, unique.Handle[Checksum]),
+	getArtifact GetArtifactFunc,
 	report func(i int, d Artifact),
 ) []*check.Absolute {
 	layers := make([]*check.Absolute, 0, len(artifacts))
@@ -67,14 +67,14 @@ func PromoteLayers(
 }
 
 // layers returns pathnames collected from A deduplicated via [PromoteLayers].
-func (p *ExecPath) layers(f *FContext) []*check.Absolute {
-	msg := f.GetMessage()
-	return PromoteLayers(p.A, f.GetArtifact, func(i int, d Artifact) {
+func (p *ExecPath) layers(
+	msg message.Msg,
+	getArtifact GetArtifactFunc,
+	ident func(a Artifact) unique.Handle[ID],
+) []*check.Absolute {
+	return PromoteLayers(p.A, getArtifact, func(i int, d Artifact) {
 		if msg.IsVerbose() {
-			msg.Verbosef(
-				"promoted layer %d as %s",
-				i, reportName(d, f.cache.Ident(d)),
-			)
+			msg.Verbosef("promoted layer %d as %s", i, reportName(d, ident(d)))
 		}
 	})
 }
@@ -186,7 +186,7 @@ func NewExec(
 	paths ...ExecPath,
 ) Artifact {
 	if name == "" {
-		name = "exec-" + path.Base(pathname.String())
+		name = "exec-" + filepath.Base(pathname.String())
 	}
 	if timeout <= 0 {
 		timeout = ExecTimeoutDefault
@@ -382,17 +382,31 @@ func scanVerbose(
 	}
 }
 
+var (
+	// ErrInvalidPaths is returned for an [Artifact] of [KindExec] or
+	// [KindExecNet] specified with invalid paths.
+	ErrInvalidPaths = errors.New("invalid mount point")
+)
+
 // SeccompPresets is the [seccomp] presets used by exec artifacts.
 const SeccompPresets = std.PresetStrict &
 	^(std.PresetDenyNS | std.PresetDenyDevel)
 
-// cure is like Cure but allows optional host net namespace. This is used for
-// the [KnownChecksum] variant where networking is allowed.
-func (a *execArtifact) cure(f *FContext, hostNet bool) (err error) {
+// makeContainer sets up the specified temp and work directories and returns the
+// corresponding [container.Container] that would have run for cure.
+func (a *execArtifact) makeContainer(
+	ctx context.Context,
+	msg message.Msg,
+	flags int,
+	hostNet bool,
+	temp, work *check.Absolute,
+	getArtifact GetArtifactFunc,
+	ident func(a Artifact) unique.Handle[ID],
+) (z *container.Container, err error) {
 	overlayWorkIndex := -1
 	for i, p := range a.paths {
 		if p.P == nil || len(p.A) == 0 {
-			return os.ErrInvalid
+			return nil, ErrInvalidPaths
 		}
 		if p.P.Is(AbsWork) {
 			overlayWorkIndex = i
@@ -404,29 +418,204 @@ func (a *execArtifact) cure(f *FContext, hostNet bool) (err error) {
 		artifactCount += len(p.A)
 	}
 
-	ctx, cancel := context.WithTimeout(f.Unwrap(), a.timeout)
-	defer cancel()
-
-	z := container.New(ctx, f.GetMessage())
+	z = container.New(ctx, msg)
 	z.WaitDelay = execWaitDelay
 	z.SeccompPresets = SeccompPresets
 	z.SeccompFlags |= seccomp.AllowMultiarch
 	z.ParentPerm = 0700
 	z.HostNet = hostNet
+	z.HostAbstract = flags&CHostAbstract != 0
 	z.Hostname = "cure"
-	z.SetScheduler = SetSchedIdle
+	z.SetScheduler = flags&CSchedIdle != 0
 	z.SchedPolicy = ext.SCHED_IDLE
 	if z.HostNet {
 		z.Hostname = "cure-net"
 	}
 	z.Uid, z.Gid = (1<<10)-1, (1<<10)-1
 
+	z.Dir, z.Env, z.Path, z.Args = a.dir, a.env, a.path, a.args
+	z.Grow(len(a.paths) + 4)
+
+	for i, b := range a.paths {
+		if i == overlayWorkIndex {
+			if err = os.MkdirAll(work.String(), 0700); err != nil {
+				return
+			}
+			tempWork := temp.Append(".work")
+			if err = os.MkdirAll(tempWork.String(), 0700); err != nil {
+				return
+			}
+			z.Overlay(
+				AbsWork,
+				work,
+				tempWork,
+				b.layers(msg, getArtifact, ident)...,
+			)
+			continue
+		}
+
+		if a.paths[i].W {
+			tempUpper, tempWork := temp.Append(
+				".upper", strconv.Itoa(i),
+			), temp.Append(
+				".work", strconv.Itoa(i),
+			)
+			if err = os.MkdirAll(tempUpper.String(), 0700); err != nil {
+				return
+			}
+			if err = os.MkdirAll(tempWork.String(), 0700); err != nil {
+				return
+			}
+			z.Overlay(b.P, tempUpper, tempWork, b.layers(msg, getArtifact, ident)...)
+		} else if len(b.A) == 1 {
+			pathname, _ := getArtifact(b.A[0])
+			z.Bind(pathname, b.P, 0)
+		} else {
+			z.OverlayReadonly(b.P, b.layers(msg, getArtifact, ident)...)
+		}
+	}
+	if overlayWorkIndex < 0 {
+		z.Bind(
+			work,
+			AbsWork,
+			std.BindWritable|std.BindEnsure,
+		)
+	}
+	z.Bind(
+		temp,
+		fhs.AbsTmp,
+		std.BindWritable|std.BindEnsure,
+	)
+	z.Proc(fhs.AbsProc).Dev(fhs.AbsDev, true)
+	return
+}
+
+var (
+	// ErrExecBusy is returned entering [Cache.EnterExec] while another
+	// goroutine has not yet returned from it.
+	ErrExecBusy = errors.New("scratch directories in use")
+	// ErrNotExec is returned for unsupported implementations of [Artifact]
+	// passed to [Cache.EnterExec].
+	ErrNotExec = errors.New("attempting to run a non-exec artifact")
+)
+
+// EnterExec runs the container of an [Artifact] of [KindExec] or [KindExecNet]
+// with its entry point, argument, and standard streams replaced with values
+// supplied by the caller.
+func (c *Cache) EnterExec(
+	ctx context.Context,
+	a Artifact,
+	retainSession bool,
+	stdin io.Reader,
+	stdout, stderr io.Writer,
+	path *check.Absolute,
+	args ...string,
+) (err error) {
+	if !c.inExec.CompareAndSwap(false, true) {
+		return ErrExecBusy
+	}
+	defer c.inExec.Store(false)
+
+	var hostNet bool
+	var e *execArtifact
+	switch f := a.(type) {
+	case *execArtifact:
+		e = f
+
+	case *execNetArtifact:
+		e = &f.execArtifact
+		hostNet = true
+
+	default:
+		return ErrNotExec
+	}
+
+	deps := Collect(a.Dependencies())
+	if _, _, err = c.Cure(&deps); err == nil {
+		return errors.New("unreachable")
+	} else if !IsCollected(err) {
+		return
+	}
+
+	dm := make(map[Artifact]cureRes)
+	for i, p := range deps {
+		var res cureRes
+		res.pathname, res.checksum, err = c.Cure(p)
+		if err != nil {
+			return
+		}
+		dm[deps[i]] = res
+	}
+
+	scratch := c.base.Append(dirExecScratch)
+	temp, work := scratch.Append("temp"), scratch.Append("work")
+	// work created during makeContainer
+	if err = os.MkdirAll(temp.String(), 0700); err != nil {
+		return
+	}
+	defer func() {
+		if chmodErr, removeErr := removeAll(scratch); chmodErr != nil || removeErr != nil {
+			err = errors.Join(err, chmodErr, removeErr)
+		}
+	}()
+
+	var z *container.Container
+	z, err = e.makeContainer(
+		ctx, c.msg,
+		c.flags,
+		hostNet,
+		temp, work,
+		func(a Artifact) (*check.Absolute, unique.Handle[Checksum]) {
+			if res, ok := dm[a]; ok {
+				return res.pathname, res.checksum
+			}
+			panic(InvalidLookupError(c.Ident(a).Value()))
+		},
+		c.Ident,
+	)
+	if err != nil {
+		return
+	}
+	z.Stdin, z.Stdout, z.Stderr = stdin, stdout, stderr
+	z.Path, z.Args = path, args
+	z.RetainSession = retainSession
+	if stdin == os.Stdin {
+		if s, ok := os.LookupEnv("TERM"); ok {
+			z.Env = append(z.Env, "TERM="+s)
+		}
+	}
+
+	if err = z.Start(); err != nil {
+		return
+	}
+	if err = z.Serve(); err != nil {
+		return
+	}
+	return z.Wait()
+}
+
+// cure is like Cure but allows optional host net namespace.
+func (a *execArtifact) cure(f *FContext, hostNet bool) (err error) {
+	ctx, cancel := context.WithTimeout(f.Unwrap(), a.timeout)
+	defer cancel()
+
+	msg := f.GetMessage()
+	var z *container.Container
+	if z, err = a.makeContainer(
+		ctx, msg, f.cache.flags, hostNet,
+		f.GetTempDir(), f.GetWorkDir(),
+		f.GetArtifact,
+		f.cache.Ident,
+	); err != nil {
+		return
+	}
+
 	var status io.Writer
 	if status, err = f.GetStatusWriter(); err != nil {
 		return
 	}
 
-	if msg := f.GetMessage(); msg.IsVerbose() {
+	if msg.IsVerbose() {
 		var stdout, stderr io.ReadCloser
 		if stdout, err = z.StdoutPipe(); err != nil {
 			return
@@ -464,62 +653,6 @@ func (a *execArtifact) cure(f *FContext, hostNet bool) (err error) {
 		z.Stdout, z.Stderr = status, status
 	}
 
-	z.Dir, z.Env, z.Path, z.Args = a.dir, a.env, a.path, a.args
-	z.Grow(len(a.paths) + 4)
-
-	temp, work := f.GetTempDir(), f.GetWorkDir()
-	for i, b := range a.paths {
-		if i == overlayWorkIndex {
-			if err = os.MkdirAll(work.String(), 0700); err != nil {
-				return
-			}
-			tempWork := temp.Append(".work")
-			if err = os.MkdirAll(tempWork.String(), 0700); err != nil {
-				return
-			}
-			z.Overlay(
-				AbsWork,
-				work,
-				tempWork,
-				b.layers(f)...,
-			)
-			continue
-		}
-
-		if a.paths[i].W {
-			tempUpper, tempWork := temp.Append(
-				".upper", strconv.Itoa(i),
-			), temp.Append(
-				".work", strconv.Itoa(i),
-			)
-			if err = os.MkdirAll(tempUpper.String(), 0700); err != nil {
-				return
-			}
-			if err = os.MkdirAll(tempWork.String(), 0700); err != nil {
-				return
-			}
-			z.Overlay(b.P, tempUpper, tempWork, b.layers(f)...)
-		} else if len(b.A) == 1 {
-			pathname, _ := f.GetArtifact(b.A[0])
-			z.Bind(pathname, b.P, 0)
-		} else {
-			z.OverlayReadonly(b.P, b.layers(f)...)
-		}
-	}
-	if overlayWorkIndex < 0 {
-		z.Bind(
-			work,
-			AbsWork,
-			std.BindWritable|std.BindEnsure,
-		)
-	}
-	z.Bind(
-		f.GetTempDir(),
-		fhs.AbsTmp,
-		std.BindWritable|std.BindEnsure,
-	)
-	z.Proc(fhs.AbsProc).Dev(fhs.AbsDev, true)
-
 	if err = z.Start(); err != nil {
 		return
 	}
@@ -532,7 +665,7 @@ func (a *execArtifact) cure(f *FContext, hostNet bool) (err error) {
 
 	// do not allow empty directories to succeed
 	for {
-		err = syscall.Rmdir(work.String())
+		err = syscall.Rmdir(f.GetWorkDir().String())
 		if err != syscall.EINTR {
 			break
 		}

internal/pkg/exec_test.go

@@ -33,8 +33,7 @@ func TestExec(t *testing.T) {
 	)
 
 	checkWithCache(t, []cacheTestCase{
-		{"offline", nil, func(t *testing.T, base *check.Absolute, c *pkg.Cache) {
-			c.SetStrict(true)
+		{"offline", pkg.CValidateKnown, nil, func(t *testing.T, base *check.Absolute, c *pkg.Cache) {
 			testtool, testtoolDestroy := newTesttool()
 
 			cureMany(t, c, []cureStep{
@@ -92,7 +91,7 @@ func TestExec(t *testing.T) {
 					[]string{"testtool"},
 
 					pkg.ExecPath{},
-				), nil, pkg.Checksum{}, os.ErrInvalid},
+				), nil, pkg.Checksum{}, pkg.ErrInvalidPaths},
 			})
 
 			// check init failure passthrough
@@ -111,8 +110,7 @@ func TestExec(t *testing.T) {
 			testtoolDestroy(t, base, c)
 		}, pkg.MustDecode("Q5DluWQCAeohLoiGRImurwFp3vdz9IfQCoj7Fuhh73s4KQPRHpEQEnHTdNHmB8Fx")},
 
-		{"net", nil, func(t *testing.T, base *check.Absolute, c *pkg.Cache) {
-			c.SetStrict(true)
+		{"net", pkg.CValidateKnown, nil, func(t *testing.T, base *check.Absolute, c *pkg.Cache) {
 			testtool, testtoolDestroy := newTesttool()
 
 			wantChecksum := pkg.MustDecode(
@@ -146,8 +144,7 @@ func TestExec(t *testing.T) {
 			testtoolDestroy(t, base, c)
 		}, pkg.MustDecode("bPYvvqxpfV7xcC1EptqyKNK1klLJgYHMDkzBcoOyK6j_Aj5hb0mXNPwTwPSK5F6Z")},
 
-		{"overlay root", nil, func(t *testing.T, base *check.Absolute, c *pkg.Cache) {
-			c.SetStrict(true)
+		{"overlay root", pkg.CValidateKnown, nil, func(t *testing.T, base *check.Absolute, c *pkg.Cache) {
 			testtool, testtoolDestroy := newTesttool()
 
 			cureMany(t, c, []cureStep{
@@ -172,8 +169,7 @@ func TestExec(t *testing.T) {
 			testtoolDestroy(t, base, c)
 		}, pkg.MustDecode("PO2DSSCa4yoSgEYRcCSZfQfwow1yRigL3Ry-hI0RDI4aGuFBha-EfXeSJnG_5_Rl")},
 
-		{"overlay work", nil, func(t *testing.T, base *check.Absolute, c *pkg.Cache) {
-			c.SetStrict(true)
+		{"overlay work", pkg.CValidateKnown, nil, func(t *testing.T, base *check.Absolute, c *pkg.Cache) {
 			testtool, testtoolDestroy := newTesttool()
 
 			cureMany(t, c, []cureStep{
@@ -203,8 +199,7 @@ func TestExec(t *testing.T) {
 			testtoolDestroy(t, base, c)
 		}, pkg.MustDecode("iaRt6l_Wm2n-h5UsDewZxQkCmjZjyL8r7wv32QT2kyV55-Lx09Dq4gfg9BiwPnKs")},
 
-		{"multiple layers", nil, func(t *testing.T, base *check.Absolute, c *pkg.Cache) {
-			c.SetStrict(true)
+		{"multiple layers", pkg.CValidateKnown, nil, func(t *testing.T, base *check.Absolute, c *pkg.Cache) {
 			testtool, testtoolDestroy := newTesttool()
 
 			cureMany(t, c, []cureStep{
@@ -256,8 +251,7 @@ func TestExec(t *testing.T) {
 			testtoolDestroy(t, base, c)
 		}, pkg.MustDecode("O2YzyR7IUGU5J2CADy0hUZ3A5NkP_Vwzs4UadEdn2oMZZVWRtH0xZGJ3HXiimTnZ")},
 
-		{"overlay layer promotion", nil, func(t *testing.T, base *check.Absolute, c *pkg.Cache) {
-			c.SetStrict(true)
+		{"overlay layer promotion", pkg.CValidateKnown, nil, func(t *testing.T, base *check.Absolute, c *pkg.Cache) {
 			testtool, testtoolDestroy := newTesttool()
 
 			cureMany(t, c, []cureStep{

internal/pkg/file_test.go

@@ -11,9 +11,7 @@ func TestFile(t *testing.T) {
 	t.Parallel()
 
 	checkWithCache(t, []cacheTestCase{
-		{"file", nil, func(t *testing.T, base *check.Absolute, c *pkg.Cache) {
-			c.SetStrict(true)
-
+		{"file", pkg.CValidateKnown, nil, func(t *testing.T, base *check.Absolute, c *pkg.Cache) {
 			cureMany(t, c, []cureStep{
 				{"short", pkg.NewFile("null", []byte{0}), base.Append(
 					"identifier",

internal/pkg/ir_test.go

@@ -85,7 +85,7 @@ func TestIRRoundtrip(t *testing.T) {
 	testCasesCache := make([]cacheTestCase, len(testCases))
 	for i, tc := range testCases {
 		want := tc.a
-		testCasesCache[i] = cacheTestCase{tc.name, nil,
+		testCasesCache[i] = cacheTestCase{tc.name, 0, nil,
 			func(t *testing.T, base *check.Absolute, c *pkg.Cache) {
 				r, w := io.Pipe()
 

internal/pkg/net_test.go

@@ -32,7 +32,7 @@ func TestHTTPGet(t *testing.T) {
 	}))
 
 	checkWithCache(t, []cacheTestCase{
-		{"direct", nil, func(t *testing.T, base *check.Absolute, c *pkg.Cache) {
+		{"direct", pkg.CValidateKnown, nil, func(t *testing.T, base *check.Absolute, c *pkg.Cache) {
 			var r pkg.RContext
 			rCacheVal := reflect.ValueOf(&r).Elem().FieldByName("cache")
 			reflect.NewAt(
@@ -94,7 +94,7 @@ func TestHTTPGet(t *testing.T) {
 			}
 		}, pkg.MustDecode("E4vEZKhCcL2gPZ2Tt59FS3lDng-d_2SKa2i5G_RbDfwGn6EemptFaGLPUDiOa94C")},
 
-		{"cure", nil, func(t *testing.T, base *check.Absolute, c *pkg.Cache) {
+		{"cure", pkg.CValidateKnown, nil, func(t *testing.T, base *check.Absolute, c *pkg.Cache) {
 			var r pkg.RContext
 			rCacheVal := reflect.ValueOf(&r).Elem().FieldByName("cache")
 			reflect.NewAt(

internal/pkg/pkg.go

@@ -13,15 +13,14 @@ import (
 	"hash"
 	"io"
 	"io/fs"
-	"iter"
 	"maps"
 	"os"
-	"path"
 	"path/filepath"
 	"runtime"
 	"slices"
 	"strings"
 	"sync"
+	"sync/atomic"
 	"syscall"
 	"testing"
 	"unique"
@@ -331,23 +330,6 @@ type FloodArtifact interface {
 	Artifact
 }
 
-// Flood returns an iterator over the dependency tree of an [Artifact].
-func Flood(a Artifact) iter.Seq[Artifact] {
-	return func(yield func(Artifact) bool) {
-		for _, d := range a.Dependencies() {
-			if !yield(d) {
-				return
-			}
-
-			for d0 := range Flood(d) {
-				if !yield(d0) {
-					return
-				}
-			}
-		}
-	}
-}
-
 // TrivialArtifact refers to an [Artifact] that cures without requiring that
 // any other [Artifact] is cured before it. Its dependency tree is ignored after
 // computing its identifier.
@@ -366,7 +348,7 @@ type TrivialArtifact interface {
 }
 
 // KnownIdent is optionally implemented by [Artifact] and is used instead of
-// [Kind.Ident] when it is available.
+// [Cache.Ident] when it is available.
 //
 // This is very subtle to use correctly. The implementation must ensure that
 // this value is globally unique, otherwise [Cache] can enter an inconsistent
@@ -439,6 +421,11 @@ const (
 	KindCustomOffset = 1 << 31
 )
 
+const (
+	// kindCollection is the kind of [Collect]. It never cures successfully.
+	kindCollection Kind = KindCustomOffset - 1 - iota
+)
+
 const (
 	// fileLock is the file name appended to Cache.base for guaranteeing
 	// exclusive access to the cache directory.
@@ -461,6 +448,11 @@ const (
 	// pathnames allocated during [Cache.Cure].
 	dirTemp = "temp"
 
+	// dirExecScratch is the directory name appended to Cache.base for scratch
+	// space setting up the container started by [Cache.EnterExec]. Exclusivity
+	// via Cache.inExec.
+	dirExecScratch = "scratch"
+
 	// checksumLinknamePrefix is prepended to the encoded [Checksum] value
 	// of an [Artifact] when creating a symbolic link to dirChecksum.
 	checksumLinknamePrefix = "../" + dirChecksum + "/"
@@ -476,7 +468,7 @@ type cureRes struct {
 // subject to the cures limit. Values pointed to by result addresses are safe
 // to access after the [sync.WaitGroup] associated with this pendingArtifactDep
 // is done. pendingArtifactDep must not be reused or modified after it is sent
-// to Cache.cureDep.
+// to cure.
 type pendingArtifactDep struct {
 	// Dependency artifact populated during [Cache.Cure].
 	a Artifact
@@ -496,6 +488,49 @@ type pendingArtifactDep struct {
 	*sync.WaitGroup
 }
 
+const (
+	// CValidateKnown arranges for [KnownChecksum] outcomes to be validated to
+	// match its intended checksum.
+	//
+	// A correct implementation of [KnownChecksum] does not successfully cure
+	// with output not matching its intended checksum. When an implementation
+	// fails to perform this validation correctly, the on-disk format enters
+	// an inconsistent state (correctable by [Cache.Scrub]).
+	//
+	// This flag causes [Cache.Cure] to always compute the checksum, and reject
+	// a cure if it does not match the intended checksum.
+	//
+	// This behaviour significantly reduces performance and is not recommended
+	// outside of testing a custom [Artifact] implementation.
+	CValidateKnown = 1 << iota
+
+	// CSchedIdle arranges for the [ext.SCHED_IDLE] scheduling priority to be
+	// set for [KindExec] and [KindExecNet] containers.
+	CSchedIdle
+
+	// CAssumeChecksum enables the use of [KnownChecksum] for duplicate function
+	// call suppression via the on-disk cache.
+	//
+	// This may cause incorrect cure outcome if an impossible checksum is
+	// specified that matches an output already present in the on-disk cache.
+	// This may be avoided by purposefully specifying a statistically
+	// unattainable checksum, like the zero value.
+	//
+	// While this optimisation might seem appealing, it is almost never
+	// applicable in real world use. Almost every time this path was taken, it
+	// was caused by an incorrect checksum accidentally left behind while
+	// bumping a package. Only enable this if you are really sure you need it.
+	CAssumeChecksum
+
+	// CHostAbstract disables restriction of sandboxed processes from connecting
+	// to an abstract UNIX socket created by a host process.
+	//
+	// This is considered less secure in some systems, but does not introduce
+	// impurity due to [KindExecNet] being [KnownChecksum]. This flag exists
+	// to support kernels without Landlock LSM enabled.
+	CHostAbstract
+)
+
 // Cache is a support layer that implementations of [Artifact] can use to store
 // cured [Artifact] data in a content addressed fashion.
 type Cache struct {
@@ -515,12 +550,8 @@ type Cache struct {
 
 	// Directory where all [Cache] related files are placed.
 	base *check.Absolute
-
-	// Whether to validate [FileArtifact.Cure] for a [KnownChecksum] file. This
-	// significantly reduces performance.
-	strict bool
-	// Maximum size of a dependency graph.
-	threshold uintptr
+	// Immutable cure options set by [Open].
+	flags int
 
 	// Artifact to [unique.Handle] of identifier cache.
 	artifact sync.Map
@@ -548,24 +579,11 @@ type Cache struct {
 	unlock func()
 	// Synchronises calls to Close.
 	closeOnce sync.Once
+
+	// Whether EnterExec has not yet returned.
+	inExec atomic.Bool
 }
 
-// IsStrict returns whether the [Cache] strictly verifies checksums.
-func (c *Cache) IsStrict() bool { return c.strict }
-
-// SetStrict sets whether the [Cache] strictly verifies checksums, even when
-// the implementation promises to validate them internally. This significantly
-// reduces performance and is not recommended outside of testing.
-//
-// This method is not safe for concurrent use with any other method.
-func (c *Cache) SetStrict(strict bool) { c.strict = strict }
-
-// SetThreshold imposes a maximum size on the dependency graph, checked on every
-// call to Cure. The zero value disables this check entirely.
-//
-// This method is not safe for concurrent use with any other method.
-func (c *Cache) SetThreshold(threshold uintptr) { c.threshold = threshold }
-
 // extIdent is a [Kind] concatenated with [ID].
 type extIdent [wordSize + len(ID{})]byte
 
@@ -880,7 +898,7 @@ func (c *Cache) Scrub(checks int) error {
 					se.DanglingIdentifiers = append(se.DanglingIdentifiers, *want)
 					seMu.Unlock()
 					return false
-				} else if err = Decode(got, path.Base(linkname)); err != nil {
+				} else if err = Decode(got, filepath.Base(linkname)); err != nil {
 					seMu.Lock()
 					lnp := dir.Append(linkname)
 					se.Errs[lnp.Handle()] = append(se.Errs[lnp.Handle()], err)
@@ -1045,7 +1063,7 @@ func (c *Cache) finaliseIdent(
 // [FileArtifact] to the filesystem. If err is nil, the caller is responsible
 // for closing the resulting [io.ReadCloser].
 func (c *Cache) openFile(f FileArtifact) (r io.ReadCloser, err error) {
-	if kc, ok := f.(KnownChecksum); ok {
+	if kc, ok := f.(KnownChecksum); c.flags&CAssumeChecksum != 0 && ok {
 		c.checksumMu.RLock()
 		r, err = os.Open(c.base.Append(
 			dirChecksum,
@@ -1216,14 +1234,6 @@ func (e InvalidArtifactError) Error() string {
 	return "artifact " + Encode(e) + " cannot be cured"
 }
 
-// DependencyError refers to an artifact with a dependency tree larger than the
-// threshold specified by a previous call to [Cache.SetThreshold].
-type DependencyError struct{ A Artifact }
-
-func (e DependencyError) Error() string {
-	return "artifact has too many dependencies"
-}
-
 // Cure cures the [Artifact] and returns its pathname and [Checksum]. Direct
 // calls to Cure are not subject to the cures limit.
 func (c *Cache) Cure(a Artifact) (
@@ -1239,18 +1249,6 @@ func (c *Cache) Cure(a Artifact) (
 	default:
 	}
 
-	if c.threshold > 0 {
-		var n uintptr
-		for range Flood(a) {
-			if n == c.threshold {
-				err = DependencyError{a}
-				return
-			}
-			n++
-		}
-		c.msg.Verbosef("visited %d artifacts", n)
-	}
-
 	return c.cure(a, true)
 }
 
@@ -1474,7 +1472,7 @@ func (c *Cache) cure(a Artifact, curesExempt bool) (
 			return
 		}
 		buf := c.getIdentBuf()
-		err = Decode((*Checksum)(buf[:]), path.Base(name))
+		err = Decode((*Checksum)(buf[:]), filepath.Base(name))
 		if err == nil {
 			checksum = unique.Make(Checksum(buf[:]))
 		}
@@ -1508,16 +1506,18 @@ func (c *Cache) cure(a Artifact, curesExempt bool) (
 			checksums,
 		)
 
-		c.checksumMu.RLock()
-		checksumFi, err = os.Stat(checksumPathname.String())
-		c.checksumMu.RUnlock()
+		if c.flags&CAssumeChecksum != 0 {
+			c.checksumMu.RLock()
+			checksumFi, err = os.Stat(checksumPathname.String())
+			c.checksumMu.RUnlock()
 
-		if err != nil {
-			if !errors.Is(err, os.ErrNotExist) {
-				return
+			if err != nil {
+				if !errors.Is(err, os.ErrNotExist) {
+					return
+				}
+
+				checksumFi, err = nil, nil
 			}
-
-			checksumFi, err = nil, nil
 		}
 	}
 
@@ -1573,7 +1573,7 @@ func (c *Cache) cure(a Artifact, curesExempt bool) (
 		}
 		r, err = f.Cure(&RContext{common{c}})
 		if err == nil {
-			if checksumPathname == nil || c.IsStrict() {
+			if checksumPathname == nil || c.flags&CValidateKnown != 0 {
 				h := sha512.New384()
 				hbw := c.getWriter(h)
 				_, err = io.Copy(w, io.TeeReader(r, hbw))
@@ -1590,7 +1590,7 @@ func (c *Cache) cure(a Artifact, curesExempt bool) (
 					if checksumPathname == nil {
 						checksum = unique.Make(Checksum(buf[:]))
 						checksums = Encode(Checksum(buf[:]))
-					} else if c.IsStrict() {
+					} else if c.flags&CValidateKnown != 0 {
 						if got := Checksum(buf[:]); got != checksum.Value() {
 							err = &ChecksumMismatchError{
 								Got:  got,
@@ -1828,10 +1828,10 @@ func (c *Cache) Close() {
 func Open(
 	ctx context.Context,
 	msg message.Msg,
-	cures int,
+	flags, cures int,
 	base *check.Absolute,
 ) (*Cache, error) {
-	return open(ctx, msg, cures, base, true)
+	return open(ctx, msg, flags, cures, base, true)
 }
 
 // open implements Open but allows omitting the [lockedfile] lock when called
@@ -1839,7 +1839,7 @@ func Open(
 func open(
 	ctx context.Context,
 	msg message.Msg,
-	cures int,
+	flags, cures int,
 	base *check.Absolute,
 	lock bool,
 ) (*Cache, error) {
@@ -1861,6 +1861,7 @@ func open(
 
 	c := Cache{
 		cures: make(chan struct{}, cures),
+		flags: flags,
 
 		msg:  msg,
 		base: base,
@@ -1890,3 +1891,33 @@ func open(
 
 	return &c, nil
 }
+
+// Collected is returned by [Collect.Cure] to indicate a successful collection.
+type Collected struct{}
+
+// Error returns a constant string to satisfy error, but should never be seen
+// by the user.
+func (Collected) Error() string { return "artifacts successfully collected" }
+
+// IsCollected returns whether the underlying error contains that of the result
+// of curing a [Collect] helper.
+func IsCollected(err error) bool { return errors.As(err, new(Collected)) }
+
+// Collect implements [pkg.FloodArtifact] to concurrently cure multiple
+// [pkg.Artifact]. It returns [Collected].
+type Collect []Artifact
+
+// Cure returns [Collected].
+func (*Collect) Cure(*FContext) error { return Collected{} }
+
+// Kind returns the hardcoded [pkg.Kind] value.
+func (*Collect) Kind() Kind { return kindCollection }
+
+// Params is a noop: dependencies are already represented in the header.
+func (*Collect) Params(*IContext) {}
+
+// Dependencies returns [Collect] as is.
+func (c *Collect) Dependencies() []Artifact { return *c }
+
+// IsExclusive returns false: Cure is a noop.
+func (*Collect) IsExclusive() bool { return false }

internal/pkg/pkg_test.go

@@ -24,6 +24,7 @@ import (
 	"hakurei.app/check"
 	"hakurei.app/container"
 	"hakurei.app/fhs"
+	"hakurei.app/internal/info"
 	"hakurei.app/internal/pkg"
 	"hakurei.app/internal/stub"
 	"hakurei.app/message"
@@ -33,7 +34,7 @@ import (
 func unsafeOpen(
 	ctx context.Context,
 	msg message.Msg,
-	cures int,
+	flags, cures int,
 	base *check.Absolute,
 	lock bool,
 ) (*pkg.Cache, error)
@@ -228,7 +229,7 @@ func TestIdent(t *testing.T) {
 	var cache *pkg.Cache
 	if a, err := check.NewAbs(t.TempDir()); err != nil {
 		t.Fatal(err)
-	} else if cache, err = pkg.Open(t.Context(), msg, 0, a); err != nil {
+	} else if cache, err = pkg.Open(t.Context(), msg, 0, 0, a); err != nil {
 		t.Fatal(err)
 	}
 	t.Cleanup(cache.Close)
@@ -252,6 +253,7 @@ func TestIdent(t *testing.T) {
 // on test completion.
 type cacheTestCase struct {
 	name  string
+	flags int
 	early func(t *testing.T, base *check.Absolute)
 	f     func(t *testing.T, base *check.Absolute, c *pkg.Cache)
 	want  pkg.Checksum
@@ -288,8 +290,20 @@ func checkWithCache(t *testing.T, testCases []cacheTestCase) {
 			msg := message.New(log.New(os.Stderr, "cache: ", 0))
 			msg.SwapVerbose(testing.Verbose())
 
+			flags := tc.flags
+
+			if info.CanDegrade {
+				if _, err := container.LandlockGetABI(); err != nil {
+					if !errors.Is(err, syscall.ENOSYS) {
+						t.Fatalf("LandlockGetABI: error = %v", err)
+					}
+					flags |= pkg.CHostAbstract
+					t.Log("Landlock LSM is unavailable, setting CHostAbstract")
+				}
+			}
+
 			var scrubFunc func() error // scrub after hashing
-			if c, err := pkg.Open(t.Context(), msg, 1<<4, base); err != nil {
+			if c, err := pkg.Open(t.Context(), msg, flags, 1<<4, base); err != nil {
 				t.Fatalf("Open: error = %v", err)
 			} else {
 				t.Cleanup(c.Close)
@@ -468,9 +482,7 @@ func TestCache(t *testing.T) {
 	}()
 
 	testCases := []cacheTestCase{
-		{"file", nil, func(t *testing.T, base *check.Absolute, c *pkg.Cache) {
-			c.SetStrict(true)
-
+		{"file", pkg.CValidateKnown | pkg.CAssumeChecksum, nil, func(t *testing.T, base *check.Absolute, c *pkg.Cache) {
 			identifier := (pkg.ID)(bytes.Repeat([]byte{
 				0x75, 0xe6, 0x9d, 0x6d, 0xe7, 0x9f,
 			}, 8))
@@ -593,7 +605,7 @@ func TestCache(t *testing.T) {
 			if c0, err := unsafeOpen(
 				t.Context(),
 				message.New(nil),
-				0, base, false,
+				0, 0, base, false,
 			); err != nil {
 				t.Fatalf("open: error = %v", err)
 			} else {
@@ -627,7 +639,7 @@ func TestCache(t *testing.T) {
 			}
 		}, pkg.MustDecode("St9rlE-mGZ5gXwiv_hzQ_B8bZP-UUvSNmf4nHUZzCMOumb6hKnheZSe0dmnuc4Q2")},
 
-		{"directory", nil, func(t *testing.T, base *check.Absolute, c *pkg.Cache) {
+		{"directory", pkg.CAssumeChecksum, nil, func(t *testing.T, base *check.Absolute, c *pkg.Cache) {
 			id := pkg.MustDecode(
 				"HnySzeLQvSBZuTUcvfmLEX_OmH4yJWWH788NxuLuv7kVn8_uPM6Ks4rqFWM2NZJY",
 			)
@@ -804,9 +816,7 @@ func TestCache(t *testing.T) {
 			})
 		}, pkg.MustDecode("WVpvsVqVKg9Nsh744x57h51AuWUoUR2nnh8Md-EYBQpk6ziyTuUn6PLtF2e0Eu_d")},
 
-		{"pending", nil, func(t *testing.T, base *check.Absolute, c *pkg.Cache) {
-			c.SetStrict(true)
-
+		{"pending", pkg.CValidateKnown, nil, func(t *testing.T, base *check.Absolute, c *pkg.Cache) {
 			wantErr := stub.UniqueError(0xcafe)
 			n, ready := make(chan struct{}), make(chan struct{})
 			go func() {
@@ -876,7 +886,54 @@ func TestCache(t *testing.T) {
 			<-wCureDone
 		}, pkg.MustDecode("E4vEZKhCcL2gPZ2Tt59FS3lDng-d_2SKa2i5G_RbDfwGn6EemptFaGLPUDiOa94C")},
 
-		{"scrub", nil, func(t *testing.T, base *check.Absolute, c *pkg.Cache) {
+		{"no assume checksum", 0, nil, func(t *testing.T, base *check.Absolute, c *pkg.Cache) {
+			makeGarbage := func(work *check.Absolute, wantErr error) error {
+				if err := os.Mkdir(work.String(), 0700); err != nil {
+					return err
+				}
+
+				if err := os.WriteFile(work.Append(
+					"check",
+				).String(), nil, 0400); err != nil {
+					return err
+				}
+
+				return wantErr
+			}
+
+			wantChecksum := pkg.MustDecode("Aubi5EG4_Y8DhL9bQ3Q4HFBhLRF7X5gt9D3CNCQfT-TeBtlRXc7Zi_JYZEMoCC7M")
+
+			cureMany(t, c, []cureStep{
+				{"create", overrideChecksum{wantChecksum, overrideIdent{pkg.ID{0xff, 0}, &stubArtifact{
+					kind: pkg.KindTar,
+					cure: func(t *pkg.TContext) error {
+						return makeGarbage(t.GetWorkDir(), nil)
+					},
+				}}}, base.Append(
+					"identifier",
+					pkg.Encode(pkg.ID{0xff, 0}),
+				), wantChecksum, nil},
+
+				{"reject", overrideChecksum{wantChecksum, overrideIdent{pkg.ID{0xfe, 1}, &stubArtifact{
+					kind: pkg.KindTar,
+					cure: func(t *pkg.TContext) error {
+						return makeGarbage(t.GetWorkDir(), stub.UniqueError(0xbad))
+					},
+				}}}, nil, pkg.Checksum{}, stub.UniqueError(0xbad)},
+
+				{"match", overrideChecksum{wantChecksum, overrideIdent{pkg.ID{0xff, 1}, &stubArtifact{
+					kind: pkg.KindTar,
+					cure: func(t *pkg.TContext) error {
+						return makeGarbage(t.GetWorkDir(), nil)
+					},
+				}}}, base.Append(
+					"identifier",
+					pkg.Encode(pkg.ID{0xff, 1}),
+				), wantChecksum, nil},
+			})
+		}, pkg.MustDecode("OC290t23aimNo2Rp2pPwan5GI2KRLRdOwYxXQMD9jw0QROgHnNXWodoWdV0hwu2w")},
+
+		{"scrub", 0, nil, func(t *testing.T, base *check.Absolute, c *pkg.Cache) {
 			cureMany(t, c, []cureStep{
 				{"bad measured file", newStubFile(
 					pkg.KindHTTPGet,
@@ -1182,7 +1239,7 @@ func (a earlyFailureF) Cure(*pkg.FContext) error {
 
 func TestDependencyCureErrorEarly(t *testing.T) {
 	checkWithCache(t, []cacheTestCase{
-		{"early", nil, func(t *testing.T, _ *check.Absolute, c *pkg.Cache) {
+		{"early", 0, nil, func(t *testing.T, _ *check.Absolute, c *pkg.Cache) {
 			_, _, err := c.Cure(earlyFailureF(8))
 			if !errors.Is(err, stub.UniqueError(0xcafe)) {
 				t.Fatalf("Cure: error = %v", err)
@@ -1205,7 +1262,7 @@ func TestNew(t *testing.T) {
 		if _, err := pkg.Open(
 			t.Context(),
 			message.New(nil),
-			0, check.MustAbs(container.Nonexistent),
+			0, 0, check.MustAbs(container.Nonexistent),
 		); !reflect.DeepEqual(err, wantErr) {
 			t.Errorf("Open: error = %#v, want %#v", err, wantErr)
 		}
@@ -1233,7 +1290,7 @@ func TestNew(t *testing.T) {
 		if _, err := pkg.Open(
 			t.Context(),
 			message.New(nil),
-			0, tempDir.Append("cache"),
+			0, 0, tempDir.Append("cache"),
 		); !reflect.DeepEqual(err, wantErr) {
 			t.Errorf("Open: error = %#v, want %#v", err, wantErr)
 		}

internal/pkg/tar.go

@@ -10,7 +10,7 @@ import (
 	"io/fs"
 	"net/http"
 	"os"
-	"path"
+	"path/filepath"
 )
 
 const (
@@ -169,7 +169,7 @@ func (a *tarArtifact) Cure(t *TContext) (err error) {
 		}
 
 		if typeflag >= '0' && typeflag <= '9' && typeflag != tar.TypeDir {
-			if err = root.MkdirAll(path.Dir(header.Name), 0700); err != nil {
+			if err = root.MkdirAll(filepath.Dir(header.Name), 0700); err != nil {
 				return
 			}
 		}

internal/pkg/tar_test.go

@@ -21,7 +21,7 @@ func TestTar(t *testing.T) {
 	t.Parallel()
 
 	checkWithCache(t, []cacheTestCase{
-		{"http", nil, func(t *testing.T, base *check.Absolute, c *pkg.Cache) {
+		{"http", 0, nil, func(t *testing.T, base *check.Absolute, c *pkg.Cache) {
 			checkTarHTTP(t, base, c, fstest.MapFS{
 				".": {Mode: fs.ModeDir | 0700},
 
@@ -42,7 +42,7 @@ func TestTar(t *testing.T) {
 			))
 		}, pkg.MustDecode("NQTlc466JmSVLIyWklm_u8_g95jEEb98PxJU-kjwxLpfdjwMWJq0G8ze9R4Vo1Vu")},
 
-		{"http expand", nil, func(t *testing.T, base *check.Absolute, c *pkg.Cache) {
+		{"http expand", 0, nil, func(t *testing.T, base *check.Absolute, c *pkg.Cache) {
 			checkTarHTTP(t, base, c, fstest.MapFS{
 				".": {Mode: fs.ModeDir | 0700},
 

internal/pkg/testdata/main.go

@@ -7,7 +7,7 @@ import (
 	"log"
 	"net"
 	"os"
-	"path"
+	"path/filepath"
 	"reflect"
 	"slices"
 	"strings"
@@ -68,7 +68,7 @@ func main() {
 	if got, err := os.Executable(); err != nil {
 		log.Fatalf("Executable: error = %v", err)
 	} else {
-		iftPath = path.Join(path.Dir(path.Dir(got)), "ift")
+		iftPath = filepath.Join(filepath.Dir(filepath.Dir(got)), "ift")
 
 		if got != wantExec {
 			switch got {
@@ -161,7 +161,7 @@ func main() {
 			}
 		}
 		if !layers {
-			if path.Base(lowerdir) != checksumEmptyDir {
+			if filepath.Base(lowerdir) != checksumEmptyDir {
 				log.Fatal("unexpected artifact checksum")
 			}
 		} else {
@@ -187,8 +187,8 @@ func main() {
 			}
 
 			if len(lowerdirs) != 2 ||
-				path.Base(lowerdirs[0]) != "MGWmEfjut2QE2xPJwTsmUzpff4BN_FEnQ7T0j7gvUCCiugJQNwqt9m151fm9D1yU" ||
-				path.Base(lowerdirs[1]) != "nY_CUdiaUM1OL4cPr5TS92FCJ3rCRV7Hm5oVTzAvMXwC03_QnTRfQ5PPs7mOU9fK" {
+				filepath.Base(lowerdirs[0]) != "MGWmEfjut2QE2xPJwTsmUzpff4BN_FEnQ7T0j7gvUCCiugJQNwqt9m151fm9D1yU" ||
+				filepath.Base(lowerdirs[1]) != "nY_CUdiaUM1OL4cPr5TS92FCJ3rCRV7Hm5oVTzAvMXwC03_QnTRfQ5PPs7mOU9fK" {
 				log.Fatalf("unexpected lowerdirs %s", strings.Join(lowerdirs, ", "))
 			}
 		}
@@ -202,12 +202,12 @@ func main() {
 		}
 
 		next()
-		if path.Base(m.Root) != "OLBgp1GsljhM2TJ-sbHjaiH9txEUvgdDTAzHv2P24donTt6_529l-9Ua0vFImLlb" {
+		if filepath.Base(m.Root) != "OLBgp1GsljhM2TJ-sbHjaiH9txEUvgdDTAzHv2P24donTt6_529l-9Ua0vFImLlb" {
 			log.Fatal("unexpected file artifact checksum")
 		}
 
 		next()
-		if path.Base(m.Root) != checksumEmptyDir {
+		if filepath.Base(m.Root) != checksumEmptyDir {
 			log.Fatal("unexpected artifact checksum")
 		}
 	}
@@ -226,13 +226,13 @@ func main() {
 			log.Fatal("unexpected work mount entry")
 		}
 	} else {
-		if path.Base(m.Root) != ident || m.Target != "/work" {
+		if filepath.Base(m.Root) != ident || m.Target != "/work" {
 			log.Fatal("unexpected work mount entry")
 		}
 	}
 
 	next()
-	if path.Base(m.Root) != ident || m.Target != "/tmp" {
+	if filepath.Base(m.Root) != ident || m.Target != "/tmp" {
 		log.Fatal("unexpected temp mount entry")
 	}