internal/info: relocate from internal

This is cleaner and makes more sense. The longer LDFLAGS was never a valid concern since it is always inserted by a script.

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

cmd/hakurei/command.go

@@ -11,21 +11,24 @@ import (
 	"strconv"
 	"sync"
 	"time"
-	_ "unsafe"
+	_ "unsafe" // for go:linkname
 
 	"hakurei.app/command"
 	"hakurei.app/container/check"
 	"hakurei.app/container/fhs"
 	"hakurei.app/hst"
-	"hakurei.app/internal"
 	"hakurei.app/internal/env"
+	"hakurei.app/internal/info"
 	"hakurei.app/internal/outcome"
+	"hakurei.app/internal/system/dbus"
 	"hakurei.app/message"
-	"hakurei.app/system/dbus"
 )
 
+// 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(_ error) error
+func optionalErrorUnwrap(err error) error
 
 func buildCommand(ctx context.Context, msg message.Msg, early *earlyHardeningErrs, out io.Writer) command.Command {
 	var (
@@ -350,7 +353,7 @@ func buildCommand(ctx context.Context, msg message.Msg, early *earlyHardeningErr
 		}).Flag(&flagShort, "short", command.BoolFlag(false), "Print instance id")
 	}
 
-	c.Command("version", "Display version information", func(args []string) error { fmt.Println(internal.Version()); return errSuccess })
+	c.Command("version", "Display version information", func(args []string) error { fmt.Println(info.Version()); return errSuccess })
 	c.Command("license", "Show full license text", func(args []string) error { fmt.Println(license); return errSuccess })
 	c.Command("template", "Produce a config template", func(args []string) error { encodeJSON(log.Fatal, os.Stdout, false, hst.Template()); return errSuccess })
 	c.Command("help", "Show this help message", func([]string) error { c.PrintHelp(); return errSuccess })

cmd/hakurei/json_test.go

@@ -1,18 +1,13 @@
-package main_test
+package main
 
 import (
-	"io"
 	"reflect"
 	"strings"
 	"testing"
-	_ "unsafe"
 
 	"hakurei.app/container/stub"
 )
 
-//go:linkname decodeJSON hakurei.app/cmd/hakurei.decodeJSON
-func decodeJSON(fatal func(v ...any), op string, r io.Reader, v any)
-
 func TestDecodeJSON(t *testing.T) {
 	t.Parallel()
 
@@ -62,9 +57,6 @@ func TestDecodeJSON(t *testing.T) {
 	}
 }
 
-//go:linkname encodeJSON hakurei.app/cmd/hakurei.encodeJSON
-func encodeJSON(fatal func(v ...any), output io.Writer, short bool, v any)
-
 func TestEncodeJSON(t *testing.T) {
 	t.Parallel()
 
@@ -74,7 +66,7 @@ func TestEncodeJSON(t *testing.T) {
 		want string
 	}{
 		{"marshaler", errorJSONMarshaler{},
-			`cannot encode json for main_test.errorJSONMarshaler: unique error 3735928559 injected by the test suite`},
+			`cannot encode json for main.errorJSONMarshaler: unique error 3735928559 injected by the test suite`},
 		{"default", func() {},
 			`cannot write json: json: unsupported type: func()`},
 	}

cmd/hakurei/print.go

@@ -12,8 +12,8 @@ import (
 	"time"
 
 	"hakurei.app/hst"
-	"hakurei.app/internal"
 	"hakurei.app/internal/env"
+	"hakurei.app/internal/info"
 	"hakurei.app/internal/outcome"
 	"hakurei.app/internal/store"
 	"hakurei.app/message"
@@ -24,20 +24,20 @@ func printShowSystem(output io.Writer, short, flagJSON bool) {
 	t := newPrinter(output)
 	defer t.MustFlush()
 
-	info := &hst.Info{Version: internal.Version(), User: new(outcome.Hsu).MustID(nil)}
-	env.CopyPaths().Copy(&info.Paths, info.User)
+	hi := &hst.Info{Version: info.Version(), User: new(outcome.Hsu).MustID(nil)}
+	env.CopyPaths().Copy(&hi.Paths, hi.User)
 
 	if flagJSON {
-		encodeJSON(log.Fatal, output, short, info)
+		encodeJSON(log.Fatal, output, short, hi)
 		return
 	}
 
-	t.Printf("Version:\t%s\n", info.Version)
-	t.Printf("User:\t%d\n", info.User)
-	t.Printf("TempDir:\t%s\n", info.TempDir)
-	t.Printf("SharePath:\t%s\n", info.SharePath)
-	t.Printf("RuntimePath:\t%s\n", info.RuntimePath)
-	t.Printf("RunDirPath:\t%s\n", info.RunDirPath)
+	t.Printf("Version:\t%s\n", hi.Version)
+	t.Printf("User:\t%d\n", hi.User)
+	t.Printf("TempDir:\t%s\n", hi.TempDir)
+	t.Printf("SharePath:\t%s\n", hi.SharePath)
+	t.Printf("RuntimePath:\t%s\n", hi.RuntimePath)
+	t.Printf("RunDirPath:\t%s\n", hi.RunDirPath)
 }
 
 // printShowInstance writes a representation of [hst.State] or [hst.Config] to output.

cmd/hpkg/proc.go

@@ -10,11 +10,11 @@ import (
 	"os/exec"
 
 	"hakurei.app/hst"
-	"hakurei.app/internal"
+	"hakurei.app/internal/info"
 	"hakurei.app/message"
 )
 
-var hakureiPathVal = internal.MustHakureiPath().String()
+var hakureiPathVal = info.MustHakureiPath().String()
 
 func mustRunApp(ctx context.Context, msg message.Msg, config *hst.Config, beforeFail func()) {
 	var (

container/check/absolute_test.go

@@ -14,8 +14,10 @@ import (
 	. "hakurei.app/container/check"
 )
 
+// unsafeAbs returns check.Absolute on any string value.
+//
 //go:linkname unsafeAbs hakurei.app/container/check.unsafeAbs
-func unsafeAbs(_ string) *Absolute
+func unsafeAbs(pathname string) *Absolute
 
 func TestAbsoluteError(t *testing.T) {
 	t.Parallel()

container/fhs/abs.go

@@ -8,8 +8,10 @@ import (
 
 /* constants in this file bypass abs check, be extremely careful when changing them! */
 
+// unsafeAbs returns check.Absolute on any string value.
+//
 //go:linkname unsafeAbs hakurei.app/container/check.unsafeAbs
-func unsafeAbs(_ string) *check.Absolute
+func unsafeAbs(pathname string) *check.Absolute
 
 var (
 	// AbsRoot is [Root] as [check.Absolute].

container/stub/exit_test.go

@@ -7,8 +7,10 @@ import (
 	"hakurei.app/container/stub"
 )
 
+// Made available here to check panic recovery behaviour.
+//
 //go:linkname handleExitNew hakurei.app/container/stub.handleExitNew
-func handleExitNew(_ testing.TB)
+func handleExitNew(t testing.TB)
 
 // overrideTFailNow overrides the Fail and FailNow method.
 type overrideTFailNow struct {

dist/release.sh

@@ -10,9 +10,9 @@ cp -rv "dist/comp" "${out}"
 
 go generate ./...
 go build -trimpath -v -o "${out}/bin/" -ldflags "-s -w -buildid= -extldflags '-static'
-  -X hakurei.app/internal.buildVersion=${VERSION}
-  -X hakurei.app/internal.hakureiPath=/usr/bin/hakurei
-  -X hakurei.app/internal.hsuPath=/usr/bin/hsu
+  -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" ./...
 
 rm -f "./${out}.tar.gz" && tar -C dist -czf "${out}.tar.gz" "${pname}"

helper/deprecated.go

@@ -0,0 +1,73 @@
+// Package helper exposes the internal/helper package.
+//
+// Deprecated: This package will be removed in 0.4.
+package helper
+
+import (
+	"context"
+	"io"
+	"os"
+	"os/exec"
+	"time"
+	_ "unsafe" // for go:linkname
+
+	"hakurei.app/container"
+	"hakurei.app/container/check"
+	"hakurei.app/internal/helper"
+	"hakurei.app/message"
+)
+
+//go:linkname WaitDelay hakurei.app/internal/helper.WaitDelay
+var WaitDelay time.Duration
+
+const (
+	// HakureiHelper is set to 1 when args fd is enabled and 0 otherwise.
+	HakureiHelper = helper.HakureiHelper
+	// HakureiStatus is set to 1 when stat fd is enabled and 0 otherwise.
+	HakureiStatus = helper.HakureiStatus
+)
+
+type Helper = helper.Helper
+
+// NewCheckedArgs returns a checked null-terminated argument writer for a copy of args.
+//
+//go:linkname NewCheckedArgs hakurei.app/internal/helper.NewCheckedArgs
+func NewCheckedArgs(args ...string) (wt io.WriterTo, err error)
+
+// MustNewCheckedArgs returns a checked null-terminated argument writer for a copy of args.
+// If s contains a NUL byte this function panics instead of returning an error.
+//
+//go:linkname MustNewCheckedArgs hakurei.app/internal/helper.MustNewCheckedArgs
+func MustNewCheckedArgs(args ...string) io.WriterTo
+
+// NewDirect initialises a new direct Helper instance with wt as the null-terminated argument writer.
+// Function argF returns an array of arguments passed directly to the child process.
+//
+//go:linkname NewDirect hakurei.app/internal/helper.NewDirect
+func NewDirect(
+	ctx context.Context,
+	name string,
+	wt io.WriterTo,
+	stat bool,
+	argF func(argsFd, statFd int) []string,
+	cmdF func(cmd *exec.Cmd),
+	extraFiles []*os.File,
+) Helper
+
+// New initialises a Helper instance with wt as the null-terminated argument writer.
+//
+//go:linkname New hakurei.app/internal/helper.New
+func New(
+	ctx context.Context,
+	msg message.Msg,
+	pathname *check.Absolute, name string,
+	wt io.WriterTo,
+	stat bool,
+	argF func(argsFd, statFd int) []string,
+	cmdF func(z *container.Container),
+	extraFiles []*os.File,
+) Helper
+
+// InternalHelperStub is an internal function but exported because it is cross-package;
+// it is part of the implementation of the helper stub.
+func InternalHelperStub() { helper.InternalHelperStub() }

helper/proc/deprecated.go

@@ -0,0 +1,63 @@
+// Deprecated: This package will be removed in 0.4.
+package proc
+
+import (
+	"context"
+	"io"
+	"os"
+	"os/exec"
+	"time"
+	_ "unsafe" // for go:linkname
+
+	"hakurei.app/internal/helper/proc"
+)
+
+//go:linkname FulfillmentTimeout hakurei.app/internal/helper/proc.FulfillmentTimeout
+var FulfillmentTimeout time.Duration
+
+// A File is an extra file with deferred initialisation.
+type File = proc.File
+
+// ExtraFilesPre is a linked list storing addresses of [os.File].
+type ExtraFilesPre = proc.ExtraFilesPre
+
+// Fulfill calls the [File.Fulfill] method on all files, starts cmd and blocks until all fulfillment completes.
+//
+//go:linkname Fulfill hakurei.app/internal/helper/proc.Fulfill
+func Fulfill(ctx context.Context,
+	v *[]*os.File, start func() error,
+	files []File, extraFiles *ExtraFilesPre,
+) (err error)
+
+// InitFile initialises f as part of the slice extraFiles points to,
+// and returns its final fd value.
+//
+//go:linkname InitFile hakurei.app/internal/helper/proc.InitFile
+func InitFile(f File, extraFiles *ExtraFilesPre) (fd uintptr)
+
+// BaseFile implements the Init method of the File interface and provides indirect access to extra file state.
+type BaseFile = proc.BaseFile
+
+//go:linkname ExtraFile hakurei.app/internal/helper/proc.ExtraFile
+func ExtraFile(cmd *exec.Cmd, f *os.File) (fd uintptr)
+
+//go:linkname ExtraFileSlice hakurei.app/internal/helper/proc.ExtraFileSlice
+func ExtraFileSlice(extraFiles *[]*os.File, f *os.File) (fd uintptr)
+
+// NewWriterTo returns a [File] that receives content from wt on fulfillment.
+//
+//go:linkname NewWriterTo hakurei.app/internal/helper/proc.NewWriterTo
+func NewWriterTo(wt io.WriterTo) File
+
+// NewStat returns a [File] implementing the behaviour
+// of the receiving end of xdg-dbus-proxy stat fd.
+//
+//go:linkname NewStat hakurei.app/internal/helper/proc.NewStat
+func NewStat(s *io.Closer) File
+
+var (
+	//go:linkname ErrStatFault hakurei.app/internal/helper/proc.ErrStatFault
+	ErrStatFault error
+	//go:linkname ErrStatRead hakurei.app/internal/helper/proc.ErrStatRead
+	ErrStatRead error
+)

hst/instance_test.go

@@ -6,11 +6,13 @@ import (
 	"reflect"
 	"testing"
 	"time"
-	_ "unsafe"
+	_ "unsafe" // for go:linkname
 
 	"hakurei.app/hst"
 )
 
+// Made available here to check time encoding behaviour of [hst.ID].
+//
 //go:linkname newInstanceID hakurei.app/hst.newInstanceID
 func newInstanceID(id *hst.ID, p uint64) error
 

internal/helper/args_test.go

@@ -7,7 +7,7 @@ import (
 	"syscall"
 	"testing"
 
-	"hakurei.app/helper"
+	"hakurei.app/internal/helper"
 )
 
 func TestArgsString(t *testing.T) {

internal/helper/cmd.go

@@ -10,7 +10,7 @@ import (
 	"sync"
 	"syscall"
 
-	"hakurei.app/helper/proc"
+	"hakurei.app/internal/helper/proc"
 )
 
 // NewDirect initialises a new direct Helper instance with wt as the null-terminated argument writer.

internal/helper/cmd_test.go

@@ -9,7 +9,7 @@ import (
 	"testing"
 
 	"hakurei.app/container"
-	"hakurei.app/helper"
+	"hakurei.app/internal/helper"
 )
 
 func TestCmd(t *testing.T) {

internal/helper/container.go

@@ -11,7 +11,7 @@ import (
 
 	"hakurei.app/container"
 	"hakurei.app/container/check"
-	"hakurei.app/helper/proc"
+	"hakurei.app/internal/helper/proc"
 	"hakurei.app/message"
 )
 

internal/helper/container_test.go

@@ -9,7 +9,7 @@ import (
 	"hakurei.app/container"
 	"hakurei.app/container/check"
 	"hakurei.app/container/fhs"
-	"hakurei.app/helper"
+	"hakurei.app/internal/helper"
 )
 
 func TestContainer(t *testing.T) {

internal/helper/helper.go

@@ -8,7 +8,7 @@ import (
 	"os"
 	"time"
 
-	"hakurei.app/helper/proc"
+	"hakurei.app/internal/helper/proc"
 )
 
 var WaitDelay = 2 * time.Second

internal/helper/helper_test.go

@@ -13,7 +13,7 @@ import (
 	"testing"
 	"time"
 
-	"hakurei.app/helper"
+	"hakurei.app/internal/helper"
 )
 
 var (

internal/helper/stub_test.go

@@ -5,7 +5,7 @@ import (
 	"testing"
 
 	"hakurei.app/container"
-	"hakurei.app/helper"
+	"hakurei.app/internal/helper"
 )
 
 func TestMain(m *testing.M) { container.TryArgv0(nil); helper.InternalHelperStub(); os.Exit(m.Run()) }

internal/info/path.go

@@ -1,4 +1,4 @@
-package internal
+package info
 
 import (
 	"log"

internal/info/path_test.go

@@ -1,4 +1,4 @@
-package internal
+package info
 
 import (
 	"reflect"

internal/info/version.go

@@ -1,4 +1,4 @@
-package internal
+package info
 
 // FallbackVersion is returned when a version string was not set by the linker.
 const FallbackVersion = "dirty"

internal/outcome/dispatcher.go

@@ -14,9 +14,9 @@ import (
 	"hakurei.app/container/check"
 	"hakurei.app/container/seccomp"
 	"hakurei.app/container/std"
-	"hakurei.app/internal"
+	"hakurei.app/internal/info"
+	"hakurei.app/internal/system/dbus"
 	"hakurei.app/message"
-	"hakurei.app/system/dbus"
 )
 
 // osFile represents [os.File].
@@ -156,7 +156,7 @@ func (direct) seccompLoad(rules []std.NativeRule, flags seccomp.ExportFlag) erro
 	return seccomp.Load(rules, flags)
 }
 
-func (direct) mustHsuPath() *check.Absolute { return internal.MustHsuPath() }
+func (direct) mustHsuPath() *check.Absolute { return info.MustHsuPath() }
 
 func (direct) dbusAddress() (session, system string) { return dbus.Address() }
 

internal/outcome/dispatcher_test.go

@@ -24,8 +24,8 @@ import (
 	"hakurei.app/container/std"
 	"hakurei.app/container/stub"
 	"hakurei.app/hst"
+	"hakurei.app/internal/system"
 	"hakurei.app/message"
-	"hakurei.app/system"
 )
 
 // call initialises a [stub.Call].

internal/outcome/finalise.go

@@ -8,8 +8,8 @@ import (
 	"os/user"
 
 	"hakurei.app/hst"
+	"hakurei.app/internal/system"
 	"hakurei.app/message"
-	"hakurei.app/system"
 )
 
 func newWithMessage(msg string) error { return newWithMessageError(msg, os.ErrInvalid) }

internal/outcome/main.go

@@ -12,6 +12,8 @@ import (
 
 // IsPollDescriptor reports whether fd is the descriptor being used by the poller.
 //
+// Made available here to determine and reject impossible fd.
+//
 //go:linkname IsPollDescriptor internal/poll.IsPollDescriptor
 func IsPollDescriptor(fd uintptr) bool
 

internal/outcome/main_test.go

@@ -21,10 +21,10 @@ import (
 	"hakurei.app/container/seccomp"
 	"hakurei.app/container/std"
 	"hakurei.app/hst"
+	"hakurei.app/internal/system"
+	"hakurei.app/internal/system/acl"
+	"hakurei.app/internal/system/dbus"
 	"hakurei.app/message"
-	"hakurei.app/system"
-	"hakurei.app/system/acl"
-	"hakurei.app/system/dbus"
 )
 
 func TestOutcomeMain(t *testing.T) {

internal/outcome/outcome.go

@@ -10,9 +10,9 @@ import (
 	"hakurei.app/container/check"
 	"hakurei.app/hst"
 	"hakurei.app/internal/env"
+	"hakurei.app/internal/system"
+	"hakurei.app/internal/system/acl"
 	"hakurei.app/message"
-	"hakurei.app/system"
-	"hakurei.app/system/acl"
 )
 
 // envAllocSize is the initial size of the env map pre-allocated when the configured env map is nil.

internal/outcome/process.go

@@ -16,10 +16,10 @@ import (
 	"hakurei.app/container/check"
 	"hakurei.app/container/fhs"
 	"hakurei.app/hst"
-	"hakurei.app/internal"
+	"hakurei.app/internal/info"
 	"hakurei.app/internal/store"
+	"hakurei.app/internal/system"
 	"hakurei.app/message"
-	"hakurei.app/system"
 )
 
 const (
@@ -39,7 +39,7 @@ func (k *outcome) main(msg message.Msg, identifierFd int) {
 	}
 
 	// read comp value early for early failure
-	hsuPath := internal.MustHsuPath()
+	hsuPath := info.MustHsuPath()
 
 	const (
 		// transitions to processCommit, or processFinal on failure

internal/outcome/spcontainer.go

@@ -16,11 +16,11 @@ import (
 	"hakurei.app/container/seccomp"
 	"hakurei.app/container/std"
 	"hakurei.app/hst"
+	"hakurei.app/internal/system"
+	"hakurei.app/internal/system/acl"
+	"hakurei.app/internal/system/dbus"
 	"hakurei.app/internal/validate"
 	"hakurei.app/message"
-	"hakurei.app/system"
-	"hakurei.app/system/acl"
-	"hakurei.app/system/dbus"
 )
 
 const varRunNscd = fhs.Var + "run/nscd"

internal/outcome/spcontainer_test.go

@@ -14,9 +14,9 @@ import (
 	"hakurei.app/container/std"
 	"hakurei.app/container/stub"
 	"hakurei.app/hst"
-	"hakurei.app/system"
-	"hakurei.app/system/acl"
-	"hakurei.app/system/dbus"
+	"hakurei.app/internal/system"
+	"hakurei.app/internal/system/acl"
+	"hakurei.app/internal/system/dbus"
 )
 
 func TestSpParamsOp(t *testing.T) {

internal/outcome/spdbus.go

@@ -5,8 +5,8 @@ import (
 
 	"hakurei.app/container/fhs"
 	"hakurei.app/hst"
-	"hakurei.app/system/acl"
-	"hakurei.app/system/dbus"
+	"hakurei.app/internal/system/acl"
+	"hakurei.app/internal/system/dbus"
 )
 
 func init() { gob.Register(new(spDBusOp)) }

internal/outcome/spdbus_test.go

@@ -6,12 +6,12 @@ import (
 
 	"hakurei.app/container"
 	"hakurei.app/container/stub"
-	"hakurei.app/helper"
 	"hakurei.app/hst"
+	"hakurei.app/internal/helper"
+	"hakurei.app/internal/system"
+	"hakurei.app/internal/system/acl"
+	"hakurei.app/internal/system/dbus"
 	"hakurei.app/message"
-	"hakurei.app/system"
-	"hakurei.app/system/acl"
-	"hakurei.app/system/dbus"
 )
 
 func TestSpDBusOp(t *testing.T) {

internal/outcome/sppulse_test.go

@@ -11,8 +11,8 @@ import (
 	"hakurei.app/container/check"
 	"hakurei.app/container/stub"
 	"hakurei.app/hst"
-	"hakurei.app/system"
-	"hakurei.app/system/acl"
+	"hakurei.app/internal/system"
+	"hakurei.app/internal/system/acl"
 )
 
 func TestSpPulseOp(t *testing.T) {

internal/outcome/spruntime.go

@@ -7,8 +7,8 @@ import (
 	"hakurei.app/container/fhs"
 	"hakurei.app/container/std"
 	"hakurei.app/hst"
-	"hakurei.app/system"
-	"hakurei.app/system/acl"
+	"hakurei.app/internal/system"
+	"hakurei.app/internal/system/acl"
 )
 
 const (

internal/outcome/spruntime_test.go

@@ -8,8 +8,8 @@ import (
 	"hakurei.app/container/std"
 	"hakurei.app/container/stub"
 	"hakurei.app/hst"
-	"hakurei.app/system"
-	"hakurei.app/system/acl"
+	"hakurei.app/internal/system"
+	"hakurei.app/internal/system/acl"
 )
 
 func TestSpRuntimeOp(t *testing.T) {

internal/outcome/sptmpdir.go

@@ -7,8 +7,8 @@ import (
 	"hakurei.app/container/fhs"
 	"hakurei.app/container/std"
 	"hakurei.app/hst"
-	"hakurei.app/system"
-	"hakurei.app/system/acl"
+	"hakurei.app/internal/system"
+	"hakurei.app/internal/system/acl"
 )
 
 func init() { gob.Register(spTmpdirOp{}) }

internal/outcome/sptmpdir_test.go

@@ -8,8 +8,8 @@ import (
 	"hakurei.app/container/std"
 	"hakurei.app/container/stub"
 	"hakurei.app/hst"
-	"hakurei.app/system"
-	"hakurei.app/system/acl"
+	"hakurei.app/internal/system"
+	"hakurei.app/internal/system/acl"
 )
 
 func TestSpTmpdirOp(t *testing.T) {

internal/outcome/spwayland.go

@@ -5,8 +5,8 @@ import (
 
 	"hakurei.app/container/check"
 	"hakurei.app/hst"
-	"hakurei.app/system/acl"
-	"hakurei.app/system/wayland"
+	"hakurei.app/internal/system/acl"
+	"hakurei.app/internal/system/wayland"
 )
 
 func init() { gob.Register(new(spWaylandOp)) }
@@ -25,8 +25,8 @@ func (s *spWaylandOp) toSystem(state *outcomeStateSys) error {
 
 	// outer wayland socket (usually `/run/user/%d/wayland-%d`)
 	var socketPath *check.Absolute
-	if name, ok := state.k.lookupEnv(wayland.WaylandDisplay); !ok {
-		state.msg.Verbose(wayland.WaylandDisplay + " is not set, assuming " + wayland.FallbackName)
+	if name, ok := state.k.lookupEnv(wayland.Display); !ok {
+		state.msg.Verbose(wayland.Display + " is not set, assuming " + wayland.FallbackName)
 		socketPath = state.sc.RuntimePath.Append(wayland.FallbackName)
 	} else if a, err := check.NewAbs(name); err != nil {
 		socketPath = state.sc.RuntimePath.Append(name)
@@ -53,7 +53,7 @@ func (s *spWaylandOp) toSystem(state *outcomeStateSys) error {
 
 func (s *spWaylandOp) toContainer(state *outcomeStateParams) error {
 	innerPath := state.runtimeDir.Append(wayland.FallbackName)
-	state.env[wayland.WaylandDisplay] = wayland.FallbackName
+	state.env[wayland.Display] = wayland.FallbackName
 	if s.SocketPath == nil {
 		state.params.Bind(state.instancePath().Append("wayland"), innerPath, 0)
 	} else {

internal/outcome/spwayland_test.go

@@ -6,9 +6,9 @@ import (
 	"hakurei.app/container"
 	"hakurei.app/container/stub"
 	"hakurei.app/hst"
-	"hakurei.app/system"
-	"hakurei.app/system/acl"
-	"hakurei.app/system/wayland"
+	"hakurei.app/internal/system"
+	"hakurei.app/internal/system/acl"
+	"hakurei.app/internal/system/wayland"
 )
 
 func TestSpWaylandOp(t *testing.T) {
@@ -47,7 +47,7 @@ func TestSpWaylandOp(t *testing.T) {
 			Ops: new(container.Ops).
 				Bind(m(wantInstancePrefix+"/wayland"), m("/run/user/1000/wayland-0"), 0),
 		}, paramsWantEnv(config, map[string]string{
-			wayland.WaylandDisplay: wayland.FallbackName,
+			wayland.Display: wayland.FallbackName,
 		}, nil), nil},
 
 		{"success direct", func(isShim, _ bool) outcomeOp {
@@ -75,7 +75,7 @@ func TestSpWaylandOp(t *testing.T) {
 			Ops: new(container.Ops).
 				Bind(m("/proc/nonexistent/wayland"), m("/run/user/1000/wayland-0"), 0),
 		}, paramsWantEnv(config, map[string]string{
-			wayland.WaylandDisplay: wayland.FallbackName,
+			wayland.Display: wayland.FallbackName,
 		}, nil), nil},
 
 		{"success", func(bool, bool) outcomeOp {
@@ -98,7 +98,7 @@ func TestSpWaylandOp(t *testing.T) {
 			Ops: new(container.Ops).
 				Bind(m(wantInstancePrefix+"/wayland"), m("/run/user/1000/wayland-0"), 0),
 		}, paramsWantEnv(config, map[string]string{
-			wayland.WaylandDisplay: wayland.FallbackName,
+			wayland.Display: wayland.FallbackName,
 		}, nil), nil},
 	})
 }

internal/outcome/spx11.go

@@ -11,7 +11,7 @@ import (
 	"hakurei.app/container/check"
 	"hakurei.app/container/fhs"
 	"hakurei.app/hst"
-	"hakurei.app/system/acl"
+	"hakurei.app/internal/system/acl"
 )
 
 var absX11SocketDir = fhs.AbsTmp.Append(".X11-unix")

internal/outcome/spx11_test.go

@@ -7,7 +7,7 @@ import (
 	"hakurei.app/container"
 	"hakurei.app/container/stub"
 	"hakurei.app/hst"
-	"hakurei.app/system/acl"
+	"hakurei.app/internal/system/acl"
 )
 
 func TestSpX11Op(t *testing.T) {

internal/store/data_test.go

@@ -27,7 +27,7 @@ func TestEntryData(t *testing.T) {
 			return buf.String()
 		}
 	}
-	templateStateGob := mustEncodeGob(newTemplateState())
+	templateStateGob := mustEncodeGob(NewTemplateState())
 
 	testCases := []struct {
 		name string
@@ -45,11 +45,11 @@ func TestEntryData(t *testing.T) {
 			Step: "validate configuration", Err: hst.ErrConfigNull,
 			Msg: "invalid configuration"}},
 
-		{"inconsistent enablement", "\x00\xff\xca\xfe\x00\x00\xff\x00" + templateStateGob, newTemplateState(), &hst.AppError{
+		{"inconsistent enablement", "\x00\xff\xca\xfe\x00\x00\xff\x00" + templateStateGob, NewTemplateState(), &hst.AppError{
 			Step: "validate state enablement", Err: os.ErrInvalid,
 			Msg: "state entry aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa has unexpected enablement byte 0xd, 0xff"}},
 
-		{"template", "\x00\xff\xca\xfe\x00\x00\x0d\xf2" + templateStateGob, newTemplateState(), nil},
+		{"template", "\x00\xff\xca\xfe\x00\x00\x0d\xf2" + templateStateGob, NewTemplateState(), nil},
 	}
 	for _, tc := range testCases {
 		t.Run(tc.name, func(t *testing.T) {
@@ -105,7 +105,7 @@ func TestEntryData(t *testing.T) {
 
 	t.Run("encode fault", func(t *testing.T) {
 		t.Parallel()
-		s := newTemplateState()
+		s := NewTemplateState()
 
 		t.Run("gob", func(t *testing.T) {
 			var want = &hst.AppError{Step: "encode state body", Err: stub.UniqueError(0xcafe)}
@@ -123,8 +123,8 @@ func TestEntryData(t *testing.T) {
 	})
 }
 
-// newTemplateState returns the address of a new template [hst.State] struct.
-func newTemplateState() *hst.State {
+// NewTemplateState returns the address of a new template [hst.State] struct.
+func NewTemplateState() *hst.State {
 	return &hst.State{
 		ID:      hst.ID(bytes.Repeat([]byte{0xaa}, len(hst.ID{}))),
 		PID:     0xcafe,

internal/store/segment_test.go

@@ -10,7 +10,7 @@ import (
 	"strings"
 	"syscall"
 	"testing"
-	_ "unsafe"
+	_ "unsafe" // for go:linkname
 
 	"hakurei.app/container/check"
 	"hakurei.app/container/stub"
@@ -18,18 +18,23 @@ import (
 	"hakurei.app/internal/store"
 )
 
-//go:linkname newTemplateState hakurei.app/internal/store.newTemplateState
-func newTemplateState() *hst.State
-
+// Made available here for direct validation of state entry files.
+//
 //go:linkname entryDecode hakurei.app/internal/store.entryDecode
 func entryDecode(r io.Reader, p *hst.State) (hst.Enablement, error)
 
+// Made available here for direct access to known segment handles.
+//
 //go:linkname newHandle hakurei.app/internal/store.newHandle
 func newHandle(base *check.Absolute, identity int) *store.Handle
 
+// Made available here to check open error handling behaviour.
+//
 //go:linkname open hakurei.app/internal/store.(*EntryHandle).open
 func open(eh *store.EntryHandle, flag int, perm os.FileMode) (*os.File, error)
 
+// Made available here to check the saveload cycle.
+//
 //go:linkname save hakurei.app/internal/store.(*EntryHandle).save
 func save(eh *store.EntryHandle, state *hst.State) error
 
@@ -91,9 +96,9 @@ func TestStateEntryHandle(t *testing.T) {
 	t.Run("saveload", func(t *testing.T) {
 		t.Parallel()
 		eh := store.EntryHandle{Pathname: check.MustAbs(t.TempDir()).Append("entry"),
-			ID: newTemplateState().ID}
+			ID: store.NewTemplateState().ID}
 
-		if err := save(&eh, newTemplateState()); err != nil {
+		if err := save(&eh, store.NewTemplateState()); err != nil {
 			t.Fatalf("save: error = %v", err)
 		}
 
@@ -112,7 +117,7 @@ func TestStateEntryHandle(t *testing.T) {
 					t.Fatal(f.Close())
 				}
 
-				if want := newTemplateState(); !reflect.DeepEqual(&got, want) {
+				if want := store.NewTemplateState(); !reflect.DeepEqual(&got, want) {
 					t.Errorf("entryDecode: %#v, want %#v", &got, want)
 				}
 			})
@@ -122,7 +127,7 @@ func TestStateEntryHandle(t *testing.T) {
 
 				if et, err := eh.Load(nil); err != nil {
 					t.Fatalf("load: error = %v", err)
-				} else if want := newTemplateState().Enablements.Unwrap(); et != want {
+				} else if want := store.NewTemplateState().Enablements.Unwrap(); et != want {
 					t.Errorf("load: et = %x, want %x", et, want)
 				}
 			})
@@ -133,7 +138,7 @@ func TestStateEntryHandle(t *testing.T) {
 				var got hst.State
 				if _, err := eh.Load(&got); err != nil {
 					t.Fatalf("load: error = %v", err)
-				} else if want := newTemplateState(); !reflect.DeepEqual(&got, want) {
+				} else if want := store.NewTemplateState(); !reflect.DeepEqual(&got, want) {
 					t.Errorf("load: %#v, want %#v", &got, want)
 				}
 			})

internal/store/store_test.go

@@ -12,13 +12,15 @@ import (
 	"syscall"
 	"testing"
 	"time"
-	_ "unsafe"
+	_ "unsafe" // for go:linkname
 
 	"hakurei.app/container/check"
 	"hakurei.app/hst"
 	"hakurei.app/internal/store"
 )
 
+// Made available here to check bigLock error handling behaviour.
+//
 //go:linkname bigLock hakurei.app/internal/store.(*Store).bigLock
 func bigLock(s *store.Store) (unlock func(), err error)
 

internal/system/acl.go

@@ -8,7 +8,7 @@ import (
 
 	"hakurei.app/container/check"
 	"hakurei.app/hst"
-	"hakurei.app/system/acl"
+	"hakurei.app/internal/system/acl"
 )
 
 // UpdatePerm calls UpdatePermType with the [Process] criteria.

internal/system/acl/acl_test.go

@@ -13,7 +13,7 @@ import (
 	"strconv"
 	"testing"
 
-	"hakurei.app/system/acl"
+	"hakurei.app/internal/system/acl"
 )
 
 const testFileName = "acl.test"

internal/system/acl/perms_test.go

@@ -3,7 +3,7 @@ package acl_test
 import (
 	"testing"
 
-	"hakurei.app/system/acl"
+	"hakurei.app/internal/system/acl"
 )
 
 func TestPerms(t *testing.T) {

internal/system/acl_test.go

@@ -7,7 +7,7 @@ import (
 
 	"hakurei.app/container/stub"
 	"hakurei.app/hst"
-	"hakurei.app/system/acl"
+	"hakurei.app/internal/system/acl"
 )
 
 func TestACLUpdateOp(t *testing.T) {

internal/system/dbus.go

@@ -13,7 +13,7 @@ import (
 
 	"hakurei.app/container"
 	"hakurei.app/hst"
-	"hakurei.app/system/dbus"
+	"hakurei.app/internal/system/dbus"
 )
 
 // ErrDBusConfig is returned when a required [hst.BusConfig] argument is nil.

internal/system/dbus/address_test.go

@@ -5,7 +5,7 @@ import (
 	"reflect"
 	"testing"
 
-	"hakurei.app/system/dbus"
+	"hakurei.app/internal/system/dbus"
 )
 
 func TestParse(t *testing.T) {

internal/system/dbus/config_test.go

@@ -7,7 +7,7 @@ import (
 	"testing"
 
 	"hakurei.app/hst"
-	"hakurei.app/system/dbus"
+	"hakurei.app/internal/system/dbus"
 )
 
 func TestConfigArgs(t *testing.T) {

internal/system/dbus/dbus_test.go

@@ -11,9 +11,9 @@ import (
 	"testing"
 	"time"
 
-	"hakurei.app/helper"
+	"hakurei.app/internal/helper"
+	"hakurei.app/internal/system/dbus"
 	"hakurei.app/message"
-	"hakurei.app/system/dbus"
 )
 
 func TestFinalise(t *testing.T) {

internal/system/dbus/proc.go

@@ -12,7 +12,7 @@ import (
 	"hakurei.app/container/check"
 	"hakurei.app/container/seccomp"
 	"hakurei.app/container/std"
-	"hakurei.app/helper"
+	"hakurei.app/internal/helper"
 	"hakurei.app/ldd"
 )
 

internal/system/dbus/proc_test.go

@@ -5,7 +5,7 @@ import (
 	"testing"
 
 	"hakurei.app/container"
-	"hakurei.app/helper"
+	"hakurei.app/internal/helper"
 )
 
 func TestMain(m *testing.M) { container.TryArgv0(nil); helper.InternalHelperStub(); os.Exit(m.Run()) }

internal/system/dbus/proxy.go

@@ -6,8 +6,8 @@ import (
 	"sync"
 	"syscall"
 
-	"hakurei.app/helper"
 	"hakurei.app/hst"
+	"hakurei.app/internal/helper"
 	"hakurei.app/message"
 )
 

internal/system/dbus_test.go

@@ -10,9 +10,9 @@ import (
 	"testing"
 
 	"hakurei.app/container/stub"
-	"hakurei.app/helper"
 	"hakurei.app/hst"
-	"hakurei.app/system/dbus"
+	"hakurei.app/internal/helper"
+	"hakurei.app/internal/system/dbus"
 )
 
 func TestDBusProxyOp(t *testing.T) {

internal/system/dispatcher.go

@@ -7,9 +7,9 @@ import (
 	"os"
 
 	"hakurei.app/hst"
-	"hakurei.app/system/acl"
-	"hakurei.app/system/dbus"
-	"hakurei.app/system/internal/xcb"
+	"hakurei.app/internal/system/acl"
+	"hakurei.app/internal/system/dbus"
+	"hakurei.app/internal/system/xcb"
 )
 
 type osFile interface {

internal/system/dispatcher_test.go

@@ -10,9 +10,9 @@ import (
 
 	"hakurei.app/container/stub"
 	"hakurei.app/hst"
-	"hakurei.app/system/acl"
-	"hakurei.app/system/dbus"
-	"hakurei.app/system/internal/xcb"
+	"hakurei.app/internal/system/acl"
+	"hakurei.app/internal/system/dbus"
+	"hakurei.app/internal/system/xcb"
 )
 
 // call initialises a [stub.Call].

internal/system/system.go

@@ -44,7 +44,7 @@ type Op interface {
 	String() string
 }
 
-// TypeString extends [Enablement.String] to support [User] and [Process].
+// TypeString extends [hst.Enablement.String] to support [User] and [Process].
 func TypeString(e hst.Enablement) string {
 	switch e {
 	case User:

internal/system/system_test.go

@@ -11,8 +11,8 @@ import (
 	"hakurei.app/container/check"
 	"hakurei.app/container/stub"
 	"hakurei.app/hst"
+	"hakurei.app/internal/system/xcb"
 	"hakurei.app/message"
-	"hakurei.app/system/internal/xcb"
 )
 
 func TestCriteria(t *testing.T) {

internal/system/wayland.go

@@ -7,8 +7,8 @@ import (
 
 	"hakurei.app/container/check"
 	"hakurei.app/hst"
-	"hakurei.app/system/acl"
-	"hakurei.app/system/wayland"
+	"hakurei.app/internal/system/acl"
+	"hakurei.app/internal/system/wayland"
 )
 
 type waylandConn interface {

internal/system/wayland/conn.go

@@ -1,4 +1,3 @@
-// Package wayland implements Wayland security_context_v1 protocol.
 package wayland
 
 import (

internal/system/wayland/wayland.go

@@ -1,3 +1,4 @@
+// Package wayland implements Wayland security_context_v1 protocol.
 package wayland
 
 //go:generate sh -c "wayland-scanner client-header `pkg-config --variable=datarootdir wayland-protocols`/wayland-protocols/staging/security-context/security-context-v1.xml security-context-v1-protocol.h"
@@ -13,10 +14,21 @@ import "C"
 import (
 	"errors"
 	"strings"
+	"syscall"
 )
 
-var (
-	ErrContainsNull = errors.New("string contains null character")
+const (
+	// Display contains the name of the server socket
+	// (https://gitlab.freedesktop.org/wayland/wayland/-/blob/1.23.1/src/wayland-client.c#L1147)
+	// which is concatenated with XDG_RUNTIME_DIR
+	// (https://gitlab.freedesktop.org/wayland/wayland/-/blob/1.23.1/src/wayland-client.c#L1171)
+	// or used as-is if absolute
+	// (https://gitlab.freedesktop.org/wayland/wayland/-/blob/1.23.1/src/wayland-client.c#L1176).
+	Display = "WAYLAND_DISPLAY"
+
+	// FallbackName is used as the wayland socket name if WAYLAND_DISPLAY is unset
+	// (https://gitlab.freedesktop.org/wayland/wayland/-/blob/1.23.1/src/wayland-client.c#L1149).
+	FallbackName = "wayland-0"
 )
 
 var resErr = [...]error{
@@ -27,10 +39,10 @@ var resErr = [...]error{
 
 func bindWaylandFd(socketPath string, fd uintptr, appID, instanceID string, syncFd uintptr) error {
 	if hasNull(appID) || hasNull(instanceID) {
-		return ErrContainsNull
+		return syscall.EINVAL
 	}
 	res := C.hakurei_bind_wayland_fd(C.CString(socketPath), C.int(fd), C.CString(appID), C.CString(instanceID), C.int(syncFd))
 	return resErr[int32(res)]
 }
 
-func hasNull(s string) bool { return strings.IndexByte(s, '\x00') > -1 }
+func hasNull(s string) bool { return strings.IndexByte(s, 0) > -1 }

internal/system/wayland_test.go

@@ -6,8 +6,8 @@ import (
 	"testing"
 
 	"hakurei.app/container/stub"
-	"hakurei.app/system/acl"
-	"hakurei.app/system/wayland"
+	"hakurei.app/internal/system/acl"
+	"hakurei.app/internal/system/wayland"
 )
 
 type stubWaylandConn struct {

internal/system/xhost.go

@@ -2,7 +2,7 @@ package system
 
 import (
 	"hakurei.app/hst"
-	"hakurei.app/system/internal/xcb"
+	"hakurei.app/internal/system/xcb"
 )
 
 // ChangeHosts inserts the target user into X11 hosts and deletes it once its [Enablement] is no longer satisfied.

internal/system/xhost_test.go

@@ -5,7 +5,7 @@ import (
 
 	"hakurei.app/container/stub"
 	"hakurei.app/hst"
-	"hakurei.app/system/internal/xcb"
+	"hakurei.app/internal/system/xcb"
 )
 
 func TestXHostOp(t *testing.T) {

package.nix

@@ -65,7 +65,7 @@ buildGoModule rec {
     lib.attrsets.foldlAttrs
       (
         ldflags: name: value:
-        ldflags ++ [ "-X hakurei.app/internal.${name}=${value}" ]
+        ldflags ++ [ "-X hakurei.app/internal/info.${name}=${value}" ]
       )
       (
         [ "-s -w" ]