From 1c3761bb53c95d75751f95e8f77d9d1e5928b968 Mon Sep 17 00:00:00 2001
From: Ophestra <cat@gensokyo.uk>
Date: Tue, 25 Aug 2026 14:48:27 +0900
Subject: 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>
---
 container/init.go | 38 +++++++++++++++++++++++++++++---------
 1 file changed, 29 insertions(+), 9 deletions(-)

(limited to 'container/init.go')

diff --git a/container/init.go b/container/init.go
index 41de58cd..510d9f59 100644
--- a/container/init.go
+++ b/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 {
+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) == 1 && filepath.Base(os.Args[0]) == initName {
 		log.SetPrefix(initName + ": ")
 		log.SetFlags(0)
-		msg = message.New(log.Default())
-	}
+		msg := message.New(log.Default())
 
-	if len(os.Args) > 0 && filepath.Base(os.Args[0]) == initName {
 		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) {}
-- 
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