container: enter init path early

There is generally no use case where any setup is required before init, and requiring the explicit function call is error-prone and unnecessary. It also causes trouble with packages using a similar trick. This change moves argv0 check early and makes it an import side effect. The stub will be removed in v0.5.

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

cmd/hakurei/main.go

@@ -46,7 +46,6 @@ import (
 	"os/signal"
 	"syscall"
 
-	"hakurei.app/container"
 	"hakurei.app/ext"
 	"hakurei.app/message"
 )
@@ -59,9 +58,6 @@ var license string
 type earlyHardeningErrs struct{ yamaLSM, dumpable error }
 
 func main() {
-	// early init path, skips root check and duplicate PR_SET_DUMPABLE
-	container.TryArgv0(nil)
-
 	log.SetFlags(0)
 	log.SetPrefix("hakurei: ")
 	msg := message.New(log.Default())

cmd/mbf/main.go

@@ -37,7 +37,6 @@ import (
 
 	"hakurei.app/check"
 	"hakurei.app/command"
-	"hakurei.app/container"
 	"hakurei.app/ext"
 	"hakurei.app/fhs"
 	"hakurei.app/internal/pkg"
@@ -67,8 +66,6 @@ func writeFileExcl(name string, data []byte, perm os.FileMode) error {
 }
 
 func main() {
-	container.TryArgv0(nil)
-
 	log.SetFlags(0)
 	log.SetPrefix("mbf: ")
 	msg := message.New(log.Default())

cmd/sharefs/fuse.go

@@ -287,7 +287,6 @@ func unsafeAddArgument(args *fuseArgs, arg string) {
 
 func _main(s ...string) (exitCode int) {
 	msg := message.New(log.Default())
-	container.TryArgv0(msg)
 	runtime.LockOSThread()
 
 	// don't mask creation mode, kernel already did that

container/autoetc.go

@@ -1,15 +1,12 @@
 package container
 
 import (
-	"encoding/gob"
 	"fmt"
 
 	"hakurei.app/check"
 	"hakurei.app/fhs"
 )
 
-func init() { gob.Register(new(AutoEtcOp)) }
-
 // Etc is a helper for appending [AutoEtcOp] to [Ops].
 func (f *Ops) Etc(host *check.Absolute, prefix string) *Ops {
 	e := &AutoEtcOp{prefix}

container/autoroot.go

@@ -1,7 +1,6 @@
 package container
 
 import (
-	"encoding/gob"
 	"fmt"
 
 	"hakurei.app/check"
@@ -9,8 +8,6 @@ import (
 	"hakurei.app/message"
 )
 
-func init() { gob.Register(new(AutoRootOp)) }
-
 // Root is a helper for appending [AutoRootOp] to [Ops].
 func (f *Ops) Root(host *check.Absolute, flags int) *Ops {
 	*f = append(*f, &AutoRootOp{host, flags, nil})

container/container_test.go

@@ -37,9 +37,6 @@ import (
 
 // Note: this package requires cgo, which is unavailable in the Go playground.
 func Example() {
-	// Must be called early if the current process starts containers.
-	container.TryArgv0(nil)
-
 	// Configure the container.
 	z := container.New(context.Background(), nil)
 	z.Hostname = "hakurei-example"
@@ -876,8 +873,6 @@ var (
 var helperCommands []func(c command.Command)
 
 func TestMain(m *testing.M) {
-	container.TryArgv0(nil)
-
 	if os.Getenv(envDoCheck) == "1" {
 		c := command.New(os.Stderr, log.Printf, "helper", func(args []string) error {
 			log.SetFlags(0)

container/init.go

@@ -2,6 +2,7 @@ package container
 
 import (
 	"context"
+	"encoding/gob"
 	"errors"
 	"fmt"
 	"log"
@@ -130,7 +131,7 @@ type initParams struct {
 	Verbose bool
 }
 
-// Init is called by [TryArgv0] if the current process is the container init.
+// Init is called if the current process is the container init.
 func Init(msg message.Msg) { initEntrypoint(direct{}, msg) }
 
 func initEntrypoint(k syscallDispatcher, msg message.Msg) {
@@ -642,18 +643,37 @@ func initEntrypoint(k syscallDispatcher, msg message.Msg) {
 // initName is the prefix used by log.std in the init process.
 const initName = "init"
 
-// TryArgv0 calls [Init] if the last element of argv0 is "init".
-// If a nil msg is passed, the system logger is used instead.
-func TryArgv0(msg message.Msg) {
-	if msg == nil {
-		log.SetPrefix(initName + ": ")
-		log.SetFlags(0)
-		msg = message.New(log.Default())
+var _ = func() struct{} {
+	for _, v := range []any{
+		(*AutoEtcOp)(nil),
+		(*AutoRootOp)(nil),
+		(*BindMountOp)(nil),
+		(*DaemonOp)(nil),
+		(*MkdirOp)(nil),
+		(*MountDevOp)(nil),
+		(*MountOverlayOp)(nil),
+		(*MountProcOp)(nil),
+		(*MountTmpfsOp)(nil),
+		(*RemountOp)(nil),
+		(*SymlinkOp)(nil),
+		(*TmpfileOp)(nil),
+	} {
+		gob.Register(v)
 	}
 
-	if len(os.Args) > 0 && filepath.Base(os.Args[0]) == initName {
+	if len(os.Args) == 1 && filepath.Base(os.Args[0]) == initName {
+		log.SetPrefix(initName + ": ")
+		log.SetFlags(0)
+		msg := message.New(log.Default())
+
 		Init(msg)
 		msg.BeforeExit()
 		os.Exit(0)
 	}
-}
+	return struct{}{}
+}()
+
+// TryArgv0 is a noop.
+//
+// Deprecated: init is now implemented as an import side effect.
+func TryArgv0(_ message.Msg) {}

container/initbind.go

@@ -1,7 +1,6 @@
 package container
 
 import (
-	"encoding/gob"
 	"fmt"
 	"os"
 	"syscall"
@@ -10,8 +9,6 @@ import (
 	"hakurei.app/container/std"
 )
 
-func init() { gob.Register(new(BindMountOp)) }
-
 // Bind is a helper for appending [BindMountOp] to [Ops].
 func (f *Ops) Bind(source, target *check.Absolute, flags int) *Ops {
 	*f = append(*f, &BindMountOp{nil, source, target, flags})

container/initdaemon.go

@@ -2,7 +2,6 @@ package container
 
 import (
 	"context"
-	"encoding/gob"
 	"errors"
 	"fmt"
 	"os"
@@ -16,8 +15,6 @@ import (
 	"hakurei.app/fhs"
 )
 
-func init() { gob.Register(new(DaemonOp)) }
-
 const (
 	// daemonTimeout is the duration a [DaemonOp] is allowed to block before the
 	// [DaemonOp.Target] marker becomes available.

container/initdev.go

@@ -1,7 +1,6 @@
 package container
 
 import (
-	"encoding/gob"
 	"fmt"
 	"path/filepath"
 	. "syscall"
@@ -10,8 +9,6 @@ import (
 	"hakurei.app/fhs"
 )
 
-func init() { gob.Register(new(MountDevOp)) }
-
 // Dev appends an [Op] that mounts a subset of host /dev.
 func (f *Ops) Dev(target *check.Absolute, mqueue bool) *Ops {
 	*f = append(*f, &MountDevOp{target, mqueue, false})

container/initmkdir.go

@@ -1,15 +1,12 @@
 package container
 
 import (
-	"encoding/gob"
 	"fmt"
 	"os"
 
 	"hakurei.app/check"
 )
 
-func init() { gob.Register(new(MkdirOp)) }
-
 // Mkdir is a helper for appending [MkdirOp] to [Ops].
 func (f *Ops) Mkdir(name *check.Absolute, perm os.FileMode) *Ops {
 	*f = append(*f, &MkdirOp{name, perm})

container/initoverlay.go

@@ -1,7 +1,6 @@
 package container
 
 import (
-	"encoding/gob"
 	"fmt"
 	"slices"
 
@@ -19,8 +18,6 @@ const (
 	intermediatePatternOverlayWork = "overlay.work.*"
 )
 
-func init() { gob.Register(new(MountOverlayOp)) }
-
 const (
 	// OverlayEphemeralUnexpectedUpper is set when [MountOverlayOp.Work] is nil
 	// and [MountOverlayOp.Upper] holds an unexpected value.

container/initplace.go

@@ -1,7 +1,6 @@
 package container
 
 import (
-	"encoding/gob"
 	"fmt"
 	"syscall"
 
@@ -14,8 +13,6 @@ const (
 	intermediatePatternTmpfile = "tmp.*"
 )
 
-func init() { gob.Register(new(TmpfileOp)) }
-
 // Place is a helper for appending [TmpfileOp] to [Ops].
 func (f *Ops) Place(name *check.Absolute, data []byte) *Ops {
 	*f = append(*f, &TmpfileOp{name, data})

container/initproc.go

@@ -1,15 +1,12 @@
 package container
 
 import (
-	"encoding/gob"
 	"fmt"
 	. "syscall"
 
 	"hakurei.app/check"
 )
 
-func init() { gob.Register(new(MountProcOp)) }
-
 // Proc is a helper for appending [MountProcOp] to [Ops].
 func (f *Ops) Proc(target *check.Absolute) *Ops {
 	*f = append(*f, &MountProcOp{target})

container/initremount.go

@@ -1,14 +1,11 @@
 package container
 
 import (
-	"encoding/gob"
 	"fmt"
 
 	"hakurei.app/check"
 )
 
-func init() { gob.Register(new(RemountOp)) }
-
 // Remount is a helper for appending [RemountOp] to [Ops].
 func (f *Ops) Remount(target *check.Absolute, flags uintptr) *Ops {
 	*f = append(*f, &RemountOp{target, flags})

container/initsymlink.go

@@ -1,15 +1,12 @@
 package container
 
 import (
-	"encoding/gob"
 	"fmt"
 	"path/filepath"
 
 	"hakurei.app/check"
 )
 
-func init() { gob.Register(new(SymlinkOp)) }
-
 // Link appends an [Op] that creates a symlink in the container filesystem.
 func (f *Ops) Link(target *check.Absolute, linkName string, dereference bool) *Ops {
 	*f = append(*f, &SymlinkOp{target, linkName, dereference})

container/inittmpfs.go

@@ -1,7 +1,6 @@
 package container
 
 import (
-	"encoding/gob"
 	"fmt"
 	"math"
 	"os"
@@ -11,8 +10,6 @@ import (
 	"hakurei.app/check"
 )
 
-func init() { gob.Register(new(MountTmpfsOp)) }
-
 type TmpfsSizeError int
 
 func (e TmpfsSizeError) Error() string {

internal/dbus/proc_test.go

@@ -4,8 +4,7 @@ import (
 	"os"
 	"testing"
 
-	"hakurei.app/container"
 	"hakurei.app/internal/helper"
 )
 
-func TestMain(m *testing.M) { container.TryArgv0(nil); helper.InternalHelperStub(); os.Exit(m.Run()) }
+func TestMain(m *testing.M) { helper.InternalHelperStub(); os.Exit(m.Run()) }

internal/helper/stub_test.go

@@ -4,8 +4,7 @@ import (
 	"os"
 	"testing"
 
-	"hakurei.app/container"
 	"hakurei.app/internal/helper"
 )
 
-func TestMain(m *testing.M) { container.TryArgv0(nil); helper.InternalHelperStub(); os.Exit(m.Run()) }
+func TestMain(m *testing.M) { helper.InternalHelperStub(); os.Exit(m.Run()) }

internal/pkg/pkg_test.go

@@ -85,8 +85,6 @@ func newRContext(tb testing.TB, c *pkg.Cache) *pkg.RContext {
 	return &r
 }
 
-func TestMain(m *testing.M) { container.TryArgv0(nil); os.Exit(m.Run()) }
-
 // overrideIdent overrides the ID method of [Artifact].
 type overrideIdent struct {
 	id pkg.ID

internal/rosa/rosa_test.go

@@ -10,7 +10,6 @@ import (
 	"testing"
 
 	"hakurei.app/check"
-	"hakurei.app/container"
 	"hakurei.app/internal/pkg"
 	"hakurei.app/internal/rosa"
 	"hakurei.app/message"
@@ -28,8 +27,6 @@ var (
 )
 
 func TestMain(m *testing.M) {
-	container.TryArgv0(nil)
-
 	code := m.Run()
 	if buildTestCache != nil {
 		buildTestCacheCancel()

ldd/exec_test.go

@@ -2,12 +2,10 @@ package ldd_test
 
 import (
 	"errors"
-	"os"
 	"os/exec"
 	"testing"
 
 	"hakurei.app/check"
-	"hakurei.app/container"
 	"hakurei.app/ldd"
 	"hakurei.app/message"
 )
@@ -42,5 +40,3 @@ func TestExec(t *testing.T) {
 		}
 	})
 }
-
-func TestMain(m *testing.M) { container.TryArgv0(nil); os.Exit(m.Run()) }