fmsg: implement suspend in writer

This removes the requirement to call fmsg.Exit on every exit path, and enables direct use of the "log" package. However, fmsg.BeforeExit is still encouraged when possible to catch exit on suspended output.

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

helper/bwrap/config_test.go

@@ -1,6 +1,7 @@
 package bwrap_test
 
 import (
+	"log"
 	"os"
 	"slices"
 	"testing"
@@ -8,11 +9,10 @@ import (
 	"git.gensokyo.uk/security/fortify/helper/bwrap"
 	"git.gensokyo.uk/security/fortify/helper/proc"
 	"git.gensokyo.uk/security/fortify/helper/seccomp"
-	"git.gensokyo.uk/security/fortify/internal/fmsg"
 )
 
 func TestConfig_Args(t *testing.T) {
-	seccomp.CPrintln = fmsg.Println
+	seccomp.CPrintln = log.Println
 	t.Cleanup(func() { seccomp.CPrintln = nil })
 
 	testCases := []struct {

helper/proc/self.go

@@ -1,26 +0,0 @@
-package proc
-
-import (
-	"os"
-	"sync"
-
-	"git.gensokyo.uk/security/fortify/internal/fmsg"
-)
-
-var (
-	executable     string
-	executableOnce sync.Once
-)
-
-func copyExecutable() {
-	if name, err := os.Executable(); err != nil {
-		fmsg.Fatalf("cannot read executable path: %v", err)
-	} else {
-		executable = name
-	}
-}
-
-func MustExecutable() string {
-	executableOnce.Do(copyExecutable)
-	return executable
-}

helper/seccomp/export_test.go

@@ -4,12 +4,12 @@ import (
 	"crypto/sha512"
 	"errors"
 	"io"
+	"log"
 	"slices"
 	"syscall"
 	"testing"
 
 	"git.gensokyo.uk/security/fortify/helper/seccomp"
-	"git.gensokyo.uk/security/fortify/internal/fmsg"
 )
 
 func TestExport(t *testing.T) {
@@ -79,7 +79,7 @@ func TestExport(t *testing.T) {
 	buf := make([]byte, 8)
 	for _, tc := range testCases {
 		t.Run(tc.name, func(t *testing.T) {
-			seccomp.CPrintln = fmsg.Println
+			seccomp.CPrintln = log.Println
 			t.Cleanup(func() { seccomp.CPrintln = nil })
 
 			e := seccomp.New(tc.opts)

helper/stub.go

@@ -14,7 +14,7 @@ import (
 
 	"git.gensokyo.uk/security/fortify/helper/bwrap"
 	"git.gensokyo.uk/security/fortify/helper/proc"
-	"git.gensokyo.uk/security/fortify/internal/fmsg"
+	"git.gensokyo.uk/security/fortify/internal"
 )
 
 // InternalChildStub is an internal function but exported because it is cross-package;
@@ -40,7 +40,7 @@ func InternalChildStub() {
 		genericStub(flagRestoreFiles(4, ap, sp))
 	}
 
-	fmsg.Exit(0)
+	internal.Exit(0)
 }
 
 // InternalReplaceExecCommand is an internal function but exported because it is cross-package;