Merge pull request #126 from bnema/fix/daemon-double-fork

fix(app): detach daemon with double fork

commit: cd0e8bd837e3a965c80ad4c49d9725098a5bc461
author: bnema · 3mo ago · 2026-07-24 17:02 UTC
committer: GitHub · 3mo ago · 2026-07-24 17:02 UTC
merge of: 07b5366 + dbcb2e8 · diff against the first parent
signature: GPG UnverifiedB5690EEEBB952194 The key is unknown

3 files · +210 -6

M internal/app/run.go +5 -0


@@ -61,6 +61,7 @@ const (
61	61		kindKill
62	62		kindCmd
63	63		kindDaemon
	64	+	kindDaemonLauncher
64	65		kindStdio
65	66		kindUDPBootstrap
66	67		kindUDPProxy

@@ -141,6 +142,8 @@ func parseArgs(args []string) (command, error) {
141	142		switch args[0] {
142	143		case "--daemon":
143	144		return command{kind: kindDaemon}, nil
	145	+	case "--daemon-launcher":
	146	+	return command{kind: kindDaemonLauncher}, nil
144	147		case "_stdio":
145	148		if len(args) > 2 {
146	149		return command{}, usagef("`_stdio` accepts at most one session name")

@@ -244,6 +247,8 @@ func dispatch(ctx context.Context, cmd command) error {
244	247		return nil
245	248		case kindDaemon:
246	249		return runDaemon()
	250	+	case kindDaemonLauncher:
	251	+	return runDaemonLauncher()
247	252		case kindStdio:
248	253		return runStdio(ctx)
249	254		case kindUDPBootstrap:


@@ -61,6 +61,7 @@ const (
61	kindKill	61		kindKill
62	kindCmd	62		kindCmd
63	kindDaemon	63		kindDaemon
		64	+	kindDaemonLauncher
64	kindStdio	65		kindStdio
65	kindUDPBootstrap	66		kindUDPBootstrap
66	kindUDPProxy	67		kindUDPProxy

@@ -141,6 +142,8 @@ func parseArgs(args []string) (command, error) {
141	switch args[0] {	142		switch args[0] {
142	case "--daemon":	143		case "--daemon":
143	return command{kind: kindDaemon}, nil	144		return command{kind: kindDaemon}, nil
		145	+	case "--daemon-launcher":
		146	+	return command{kind: kindDaemonLauncher}, nil
144	case "_stdio":	147		case "_stdio":
145	if len(args) > 2 {	148		if len(args) > 2 {
146	return command{}, usagef("`_stdio` accepts at most one session name")	149		return command{}, usagef("`_stdio` accepts at most one session name")

@@ -244,6 +247,8 @@ func dispatch(ctx context.Context, cmd command) error {
244	return nil	247		return nil
245	case kindDaemon:	248		case kindDaemon:
246	return runDaemon()	249		return runDaemon()
		250	+	case kindDaemonLauncher:
		251	+	return runDaemonLauncher()
247	case kindStdio:	252		case kindStdio:
248	return runStdio(ctx)	253		return runStdio(ctx)
249	case kindUDPBootstrap:	254		case kindUDPBootstrap:

M internal/app/spawn.go +35 -6

@@ -1,6 +1,7 @@
1	1		package app
2	2
3	3		import (
	4	+	"bytes"
4	5		"context"
5	6		"errors"
6	7		"fmt"

@@ -152,10 +153,9 @@ func realDial(ctx context.Context, dir string) (ports.Transport, error) {
152	153		return ipc.DialContext(ctx, dir)
153	154		}
154	155
155		-	// realSpawn re-execs this binary as a detached daemon: a new session
156		-	// (Setsid) with stdio bound to /dev/null so it survives the client's exit
157		-	// and never writes to the client's terminal. It logs via slog to the shared
158		-	// log file instead.
	156	+	// realSpawn re-execs this binary through a short-lived launcher. Waiting for
	157	+	// that launcher to exit ensures the daemon has been re-parented before the
	158	+	// client continues, keeping process-tree termination from reaching it.
159	159		func realSpawn() error {
160	160		exePath, err := selfExePath()
161	161		if err != nil {

@@ -168,6 +168,37 @@ func realSpawn() error {
168	168		}
169	169		defer func() { _ = devNull.Close() }()
170	170
	171	+	var stderr bytes.Buffer
	172	+	cmd := exec.Command(exePath, "--daemon-launcher")
	173	+	cmd.Dir = platform.DirOrHome("")
	174	+	cmd.Stdin = devNull
	175	+	cmd.Stdout = devNull
	176	+	cmd.Stderr = &stderr
	177	+	if err := cmd.Run(); err != nil {
	178	+	if detail := bytes.TrimSpace(stderr.Bytes()); len(detail) > 0 {
	179	+	return fmt.Errorf("%w: %s", err, detail)
	180	+	}
	181	+	return err
	182	+	}
	183	+	slog.Info("daemon process detached")
	184	+	return nil
	185	+	}
	186	+
	187	+	// runDaemonLauncher is the intermediate half of the double-fork. It starts
	188	+	// the long-lived daemon in a new session and exits immediately; realSpawn
	189	+	// waits for this exit so the daemon is no longer descended from the client.
	190	+	func runDaemonLauncher() error {
	191	+	exePath, err := selfExePath()
	192	+	if err != nil {
	193	+	return fmt.Errorf("resolving executable path: %w", err)
	194	+	}
	195	+
	196	+	devNull, err := os.OpenFile(os.DevNull, os.O_RDWR, 0)
	197	+	if err != nil {
	198	+	return fmt.Errorf("opening %s: %w", os.DevNull, err)
	199	+	}
	200	+	defer func() { _ = devNull.Close() }()
	201	+
171	202		cmd := exec.Command(exePath, "--daemon")
172	203		cmd.Dir = platform.DirOrHome("")
173	204		cmd.Stdin = devNull

@@ -177,7 +208,5 @@ func realSpawn() error {
177	208		if err := cmd.Start(); err != nil {
178	209		return err
179	210		}
180		-	slog.Info("daemon process started", "pid", cmd.Process.Pid)
181		-	// Detach: we neither wait for nor signal the daemon after launch.
182	211		return cmd.Process.Release()
183	212		}

@@ -1,6 +1,7 @@
1		package app	1		package app
2			2
3		import (	3		import (
			4	+	"bytes"
4		"context"	5		"context"
5		"errors"	6		"errors"
6		"fmt"	7		"fmt"

@@ -152,10 +153,9 @@ func realDial(ctx context.Context, dir string) (ports.Transport, error) {
152		return ipc.DialContext(ctx, dir)	153		return ipc.DialContext(ctx, dir)
153		}	154		}
154			155
155	-	// realSpawn re-execs this binary as a detached daemon: a new session	156	+	// realSpawn re-execs this binary through a short-lived launcher. Waiting for
156	-	// (Setsid) with stdio bound to /dev/null so it survives the client's exit	157	+	// that launcher to exit ensures the daemon has been re-parented before the
157	-	// and never writes to the client's terminal. It logs via slog to the shared	158	+	// client continues, keeping process-tree termination from reaching it.
158	-	// log file instead.
159		func realSpawn() error {	159		func realSpawn() error {
160		exePath, err := selfExePath()	160		exePath, err := selfExePath()
161		if err != nil {	161		if err != nil {

@@ -168,6 +168,37 @@ func realSpawn() error {
168		}	168		}
169		defer func() { _ = devNull.Close() }()	169		defer func() { _ = devNull.Close() }()
170			170
			171	+	var stderr bytes.Buffer
			172	+	cmd := exec.Command(exePath, "--daemon-launcher")
			173	+	cmd.Dir = platform.DirOrHome("")
			174	+	cmd.Stdin = devNull
			175	+	cmd.Stdout = devNull
			176	+	cmd.Stderr = &stderr
			177	+	if err := cmd.Run(); err != nil {
			178	+	if detail := bytes.TrimSpace(stderr.Bytes()); len(detail) > 0 {
			179	+	return fmt.Errorf("%w: %s", err, detail)
			180	+	}
			181	+	return err
			182	+	}
			183	+	slog.Info("daemon process detached")
			184	+	return nil
			185	+	}
			186	+
			187	+	// runDaemonLauncher is the intermediate half of the double-fork. It starts
			188	+	// the long-lived daemon in a new session and exits immediately; realSpawn
			189	+	// waits for this exit so the daemon is no longer descended from the client.
			190	+	func runDaemonLauncher() error {
			191	+	exePath, err := selfExePath()
			192	+	if err != nil {
			193	+	return fmt.Errorf("resolving executable path: %w", err)
			194	+	}
			195	+
			196	+	devNull, err := os.OpenFile(os.DevNull, os.O_RDWR, 0)
			197	+	if err != nil {
			198	+	return fmt.Errorf("opening %s: %w", os.DevNull, err)
			199	+	}
			200	+	defer func() { _ = devNull.Close() }()
			201	+
171		cmd := exec.Command(exePath, "--daemon")	202		cmd := exec.Command(exePath, "--daemon")
172		cmd.Dir = platform.DirOrHome("")	203		cmd.Dir = platform.DirOrHome("")
173		cmd.Stdin = devNull	204		cmd.Stdin = devNull

@@ -177,7 +208,5 @@ func realSpawn() error {
177		if err := cmd.Start(); err != nil {	208		if err := cmd.Start(); err != nil {
178		return err	209		return err
179		}	210		}
180	-	slog.Info("daemon process started", "pid", cmd.Process.Pid)
181	-	// Detach: we neither wait for nor signal the daemon after launch.
182		return cmd.Process.Release()	211		return cmd.Process.Release()
183		}	212		}

M internal/app/spawn_test.go +170 -0


@@ -3,10 +3,13 @@ package app
3	3		import (
4	4		"context"
5	5		"errors"
	6	+	"fmt"
6	7		"os"
7	8		"path/filepath"
	9	+	"strconv"
8	10		"sync"
9	11		"sync/atomic"
	12	+	"syscall"
10	13		"testing"
11	14		"time"
12	15

@@ -16,6 +19,173 @@ import (
16	19
17	20		var errDialFailed = errors.New("dial failed")
18	21
	22	+	const (
	23	+	spawnTestChildFileEnv = "VEV_SPAWN_TEST_CHILD_FILE"
	24	+	spawnTestLauncherFileEnv = "VEV_SPAWN_TEST_LAUNCHER_FILE"
	25	+	spawnTestReleaseFileEnv = "VEV_SPAWN_TEST_RELEASE_FILE"
	26	+	)
	27	+
	28	+	func TestMain(m *testing.M) {
	29	+	if len(os.Args) == 2 {
	30	+	switch os.Args[1] {
	31	+	case "--daemon-launcher":
	32	+	launcherFile := os.Getenv(spawnTestLauncherFileEnv)
	33	+	if launcherFile != "" {
	34	+	if err := writeProcessRecord(launcherFile); err != nil {
	35	+	os.Exit(2)
	36	+	}
	37	+	}
	38	+	if err := Run(os.Args[1:]); err != nil {
	39	+	os.Exit(2)
	40	+	}
	41	+	if releaseFile := os.Getenv(spawnTestReleaseFileEnv); releaseFile != "" {
	42	+	deadline := time.Now().Add(5 * time.Second)
	43	+	for {
	44	+	if _, err := os.Stat(releaseFile); err == nil {
	45	+	break
	46	+	} else if !errors.Is(err, os.ErrNotExist) \|\| !time.Now().Before(deadline) {
	47	+	os.Exit(2)
	48	+	}
	49	+	time.Sleep(10 * time.Millisecond)
	50	+	}
	51	+	}
	52	+	os.Exit(0)
	53	+	case "--daemon":
	54	+	path := os.Getenv(spawnTestChildFileEnv)
	55	+	if path == "" {
	56	+	os.Exit(2)
	57	+	}
	58	+	if err := writeProcessRecord(path); err != nil {
	59	+	os.Exit(2)
	60	+	}
	61	+	for {
	62	+	time.Sleep(time.Hour)
	63	+	}
	64	+	}
	65	+	}
	66	+	os.Exit(m.Run())
	67	+	}
	68	+
	69	+	func TestRealSpawnWaitsForLauncherExit(t *testing.T) {
	70	+	dir := t.TempDir()
	71	+	childFile := filepath.Join(dir, "daemon.pid")
	72	+	launcherFile := filepath.Join(dir, "launcher.pid")
	73	+	releaseFile := filepath.Join(dir, "release-launcher")
	74	+	t.Setenv(spawnTestChildFileEnv, childFile)
	75	+	t.Setenv(spawnTestLauncherFileEnv, launcherFile)
	76	+	t.Setenv(spawnTestReleaseFileEnv, releaseFile)
	77	+
	78	+	// Register cleanup before starting either subprocess. The release marker
	79	+	// unblocks a launcher even when setup or an assertion fails, and PID files
	80	+	// let cleanup terminate every helper that reached its acknowledgement.
	81	+	t.Cleanup(func() {
	82	+	_ = os.WriteFile(releaseFile, nil, 0o600)
	83	+	for _, path := range []string{launcherFile, childFile} {
	84	+	if err := terminateProcessFromFile(path); err != nil {
	85	+	t.Errorf("clean up %s: %v", filepath.Base(path), err)
	86	+	}
	87	+	}
	88	+	})
	89	+
	90	+	spawnResult := make(chan error, 1)
	91	+	go func() {
	92	+	spawnResult <- realSpawn()
	93	+	}()
	94	+
	95	+	launcherPID := waitForProcessRecord(t, launcherFile)
	96	+	daemonPID := waitForProcessRecord(t, childFile)
	97	+
	98	+	select {
	99	+	case err := <-spawnResult:
	100	+	t.Fatalf("realSpawn returned while launcher %d was still running: %v", launcherPID, err)
	101	+	default:
	102	+	}
	103	+	if err := syscall.Kill(launcherPID, 0); err != nil {
	104	+	t.Fatalf("launcher exited before release acknowledgement: %v", err)
	105	+	}
	106	+
	107	+	if err := os.WriteFile(releaseFile, nil, 0o600); err != nil {
	108	+	t.Fatalf("release launcher: %v", err)
	109	+	}
	110	+	select {
	111	+	case err := <-spawnResult:
	112	+	if err != nil {
	113	+	t.Fatalf("realSpawn: %v", err)
	114	+	}
	115	+	case <-time.After(2 * time.Second):
	116	+	t.Fatal("realSpawn did not return after launcher release")
	117	+	}
	118	+
	119	+	if err := waitForProcessExit(launcherPID, 2*time.Second); err != nil {
	120	+	t.Fatalf("launcher still exists after realSpawn returned: %v", err)
	121	+	}
	122	+	if err := syscall.Kill(daemonPID, 0); err != nil {
	123	+	t.Fatalf("daemon exited with its launcher: %v", err)
	124	+	}
	125	+	}
	126	+
	127	+	func waitForProcessRecord(t *testing.T, path string) int {
	128	+	t.Helper()
	129	+	deadline := time.Now().Add(2 * time.Second)
	130	+	for time.Now().Before(deadline) {
	131	+	data, err := os.ReadFile(path)
	132	+	if err == nil {
	133	+	pid, err := strconv.Atoi(string(data))
	134	+	if err != nil {
	135	+	t.Fatalf("parse process record %s: %v", filepath.Base(path), err)
	136	+	}
	137	+	return pid
	138	+	}
	139	+	if !errors.Is(err, os.ErrNotExist) {
	140	+	t.Fatalf("read process record %s: %v", filepath.Base(path), err)
	141	+	}
	142	+	time.Sleep(10 * time.Millisecond)
	143	+	}
	144	+	t.Fatalf("process did not write %s", filepath.Base(path))
	145	+	return 0
	146	+	}
	147	+
	148	+	func waitForProcessExit(pid int, timeout time.Duration) error {
	149	+	deadline := time.Now().Add(timeout)
	150	+	for time.Now().Before(deadline) {
	151	+	err := syscall.Kill(pid, 0)
	152	+	if errors.Is(err, syscall.ESRCH) {
	153	+	return nil
	154	+	}
	155	+	if err != nil && !errors.Is(err, syscall.EPERM) {
	156	+	return err
	157	+	}
	158	+	time.Sleep(10 * time.Millisecond)
	159	+	}
	160	+	return fmt.Errorf("process %d did not exit within %s", pid, timeout)
	161	+	}
	162	+
	163	+	func writeProcessRecord(path string) error {
	164	+	tmp := path + ".tmp"
	165	+	if err := os.WriteFile(tmp, []byte(strconv.Itoa(os.Getpid())), 0o600); err != nil {
	166	+	return err
	167	+	}
	168	+	return os.Rename(tmp, path)
	169	+	}
	170	+
	171	+	func terminateProcessFromFile(path string) error {
	172	+	data, err := os.ReadFile(path)
	173	+	if errors.Is(err, os.ErrNotExist) {
	174	+	return nil
	175	+	}
	176	+	if err != nil {
	177	+	return err
	178	+	}
	179	+	pid, err := strconv.Atoi(string(data))
	180	+	if err != nil {
	181	+	return err
	182	+	}
	183	+	if err := syscall.Kill(pid, syscall.SIGKILL); err != nil && !errors.Is(err, syscall.ESRCH) {
	184	+	return err
	185	+	}
	186	+	return waitForProcessExit(pid, 2*time.Second)
	187	+	}
	188	+
19	189		// fastBackoff keeps the retry loop snappy for tests.
20	190		var fastBackoff = backoffConfig{initial: time.Millisecond, max: 5 * time.Millisecond, total: 100 * time.Millisecond}
21	191


@@ -3,10 +3,13 @@ package app
3	import (	3		import (
4	"context"	4		"context"
5	"errors"	5		"errors"
		6	+	"fmt"
6	"os"	7		"os"
7	"path/filepath"	8		"path/filepath"
		9	+	"strconv"
8	"sync"	10		"sync"
9	"sync/atomic"	11		"sync/atomic"
		12	+	"syscall"
10	"testing"	13		"testing"
11	"time"	14		"time"
12		15

@@ -16,6 +19,173 @@ import (
16		19
17	var errDialFailed = errors.New("dial failed")	20		var errDialFailed = errors.New("dial failed")
18		21
		22	+	const (
		23	+	spawnTestChildFileEnv = "VEV_SPAWN_TEST_CHILD_FILE"
		24	+	spawnTestLauncherFileEnv = "VEV_SPAWN_TEST_LAUNCHER_FILE"
		25	+	spawnTestReleaseFileEnv = "VEV_SPAWN_TEST_RELEASE_FILE"
		26	+	)
		27	+
		28	+	func TestMain(m *testing.M) {
		29	+	if len(os.Args) == 2 {
		30	+	switch os.Args[1] {
		31	+	case "--daemon-launcher":
		32	+	launcherFile := os.Getenv(spawnTestLauncherFileEnv)
		33	+	if launcherFile != "" {
		34	+	if err := writeProcessRecord(launcherFile); err != nil {
		35	+	os.Exit(2)
		36	+	}
		37	+	}
		38	+	if err := Run(os.Args[1:]); err != nil {
		39	+	os.Exit(2)
		40	+	}
		41	+	if releaseFile := os.Getenv(spawnTestReleaseFileEnv); releaseFile != "" {
		42	+	deadline := time.Now().Add(5 * time.Second)
		43	+	for {
		44	+	if _, err := os.Stat(releaseFile); err == nil {
		45	+	break
		46	+	} else if !errors.Is(err, os.ErrNotExist) \|\| !time.Now().Before(deadline) {
		47	+	os.Exit(2)
		48	+	}
		49	+	time.Sleep(10 * time.Millisecond)
		50	+	}
		51	+	}
		52	+	os.Exit(0)
		53	+	case "--daemon":
		54	+	path := os.Getenv(spawnTestChildFileEnv)
		55	+	if path == "" {
		56	+	os.Exit(2)
		57	+	}
		58	+	if err := writeProcessRecord(path); err != nil {
		59	+	os.Exit(2)
		60	+	}
		61	+	for {
		62	+	time.Sleep(time.Hour)
		63	+	}
		64	+	}
		65	+	}
		66	+	os.Exit(m.Run())
		67	+	}
		68	+
		69	+	func TestRealSpawnWaitsForLauncherExit(t *testing.T) {
		70	+	dir := t.TempDir()
		71	+	childFile := filepath.Join(dir, "daemon.pid")
		72	+	launcherFile := filepath.Join(dir, "launcher.pid")
		73	+	releaseFile := filepath.Join(dir, "release-launcher")
		74	+	t.Setenv(spawnTestChildFileEnv, childFile)
		75	+	t.Setenv(spawnTestLauncherFileEnv, launcherFile)
		76	+	t.Setenv(spawnTestReleaseFileEnv, releaseFile)
		77	+
		78	+	// Register cleanup before starting either subprocess. The release marker
		79	+	// unblocks a launcher even when setup or an assertion fails, and PID files
		80	+	// let cleanup terminate every helper that reached its acknowledgement.
		81	+	t.Cleanup(func() {
		82	+	_ = os.WriteFile(releaseFile, nil, 0o600)
		83	+	for _, path := range []string{launcherFile, childFile} {
		84	+	if err := terminateProcessFromFile(path); err != nil {
		85	+	t.Errorf("clean up %s: %v", filepath.Base(path), err)
		86	+	}
		87	+	}
		88	+	})
		89	+
		90	+	spawnResult := make(chan error, 1)
		91	+	go func() {
		92	+	spawnResult <- realSpawn()
		93	+	}()
		94	+
		95	+	launcherPID := waitForProcessRecord(t, launcherFile)
		96	+	daemonPID := waitForProcessRecord(t, childFile)
		97	+
		98	+	select {
		99	+	case err := <-spawnResult:
		100	+	t.Fatalf("realSpawn returned while launcher %d was still running: %v", launcherPID, err)
		101	+	default:
		102	+	}
		103	+	if err := syscall.Kill(launcherPID, 0); err != nil {
		104	+	t.Fatalf("launcher exited before release acknowledgement: %v", err)
		105	+	}
		106	+
		107	+	if err := os.WriteFile(releaseFile, nil, 0o600); err != nil {
		108	+	t.Fatalf("release launcher: %v", err)
		109	+	}
		110	+	select {
		111	+	case err := <-spawnResult:
		112	+	if err != nil {
		113	+	t.Fatalf("realSpawn: %v", err)
		114	+	}
		115	+	case <-time.After(2 * time.Second):
		116	+	t.Fatal("realSpawn did not return after launcher release")
		117	+	}
		118	+
		119	+	if err := waitForProcessExit(launcherPID, 2*time.Second); err != nil {
		120	+	t.Fatalf("launcher still exists after realSpawn returned: %v", err)
		121	+	}
		122	+	if err := syscall.Kill(daemonPID, 0); err != nil {
		123	+	t.Fatalf("daemon exited with its launcher: %v", err)
		124	+	}
		125	+	}
		126	+
		127	+	func waitForProcessRecord(t *testing.T, path string) int {
		128	+	t.Helper()
		129	+	deadline := time.Now().Add(2 * time.Second)
		130	+	for time.Now().Before(deadline) {
		131	+	data, err := os.ReadFile(path)
		132	+	if err == nil {
		133	+	pid, err := strconv.Atoi(string(data))
		134	+	if err != nil {
		135	+	t.Fatalf("parse process record %s: %v", filepath.Base(path), err)
		136	+	}
		137	+	return pid
		138	+	}
		139	+	if !errors.Is(err, os.ErrNotExist) {
		140	+	t.Fatalf("read process record %s: %v", filepath.Base(path), err)
		141	+	}
		142	+	time.Sleep(10 * time.Millisecond)
		143	+	}
		144	+	t.Fatalf("process did not write %s", filepath.Base(path))
		145	+	return 0
		146	+	}
		147	+
		148	+	func waitForProcessExit(pid int, timeout time.Duration) error {
		149	+	deadline := time.Now().Add(timeout)
		150	+	for time.Now().Before(deadline) {
		151	+	err := syscall.Kill(pid, 0)
		152	+	if errors.Is(err, syscall.ESRCH) {
		153	+	return nil
		154	+	}
		155	+	if err != nil && !errors.Is(err, syscall.EPERM) {
		156	+	return err
		157	+	}
		158	+	time.Sleep(10 * time.Millisecond)
		159	+	}
		160	+	return fmt.Errorf("process %d did not exit within %s", pid, timeout)
		161	+	}
		162	+
		163	+	func writeProcessRecord(path string) error {
		164	+	tmp := path + ".tmp"
		165	+	if err := os.WriteFile(tmp, []byte(strconv.Itoa(os.Getpid())), 0o600); err != nil {
		166	+	return err
		167	+	}
		168	+	return os.Rename(tmp, path)
		169	+	}
		170	+
		171	+	func terminateProcessFromFile(path string) error {
		172	+	data, err := os.ReadFile(path)
		173	+	if errors.Is(err, os.ErrNotExist) {
		174	+	return nil
		175	+	}
		176	+	if err != nil {
		177	+	return err
		178	+	}
		179	+	pid, err := strconv.Atoi(string(data))
		180	+	if err != nil {
		181	+	return err
		182	+	}
		183	+	if err := syscall.Kill(pid, syscall.SIGKILL); err != nil && !errors.Is(err, syscall.ESRCH) {
		184	+	return err
		185	+	}
		186	+	return waitForProcessExit(pid, 2*time.Second)
		187	+	}
		188	+
19	// fastBackoff keeps the retry loop snappy for tests.	189		// fastBackoff keeps the retry loop snappy for tests.
20	var fastBackoff = backoffConfig{initial: time.Millisecond, max: 5 * time.Millisecond, total: 100 * time.Millisecond}	190		var fastBackoff = backoffConfig{initial: time.Millisecond, max: 5 * time.Millisecond, total: 100 * time.Millisecond}
21		191