Use for range over integers

This appears in Go 1.22 (see https://tip.golang.org/ref/spec#For_range).

Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>

delete.go

@@ -15,7 +15,7 @@ import (
 
 func killContainer(container *libcontainer.Container) error {
 	_ = container.Signal(unix.SIGKILL)
-	for i := 0; i < 100; i++ {
+	for range 100 {
 		time.Sleep(100 * time.Millisecond)
 		if err := container.Signal(unix.Signal(0)); err != nil {
 			return container.Destroy()

libcontainer/criu_linux.go

@@ -832,7 +832,7 @@ func logCriuErrors(dir, file string) {
 			logrus.Warn("...")
 		}
 		// Print the last lines.
-		for add := 0; add < max; add++ {
+		for add := range max {
 			i := (idx + add) % max
 			s := lines[i]
 			actLineNo := lineNo + add - max + 1
@@ -961,7 +961,7 @@ func (c *Container) criuSwrk(process *Process, req *criurpc.CriuReq, opts *CriuO
 
 		val := reflect.ValueOf(req.GetOpts())
 		v := reflect.Indirect(val)
-		for i := 0; i < v.NumField(); i++ {
+		for i := range v.NumField() {
 			st := v.Type()
 			name := st.Field(i).Name
 			if 'A' <= name[0] && name[0] <= 'Z' {

libcontainer/factory_linux.go

@@ -191,7 +191,7 @@ func validateID(id string) error {
 	}
 
 	// Allowed characters: 0-9 A-Z a-z _ + - .
-	for i := 0; i < len(id); i++ {
+	for i := range len(id) {
 		c := id[i]
 		switch {
 		case c >= 'a' && c <= 'z':

libcontainer/integration/bench_test.go

@@ -60,7 +60,7 @@ func genBigEnv(count int) []string {
 	}
 
 	envs := make([]string, count)
-	for i := 0; i < count; i++ {
+	for i := range count {
 		key := strings.ToUpper(randStr(10))
 		value := randStr(20)
 		envs[i] = key + "=" + value

libcontainer/integration/execin_test.go

@@ -209,7 +209,7 @@ func TestExecInError(t *testing.T) {
 	}()
 	ok(t, err)
 
-	for i := 0; i < 42; i++ {
+	for range 42 {
 		unexistent := &libcontainer.Process{
 			Cwd:  "/",
 			Args: []string{"unexistent"},
@@ -263,7 +263,7 @@ func TestExecInTTY(t *testing.T) {
 
 	// Repeat to increase chances to catch a race; see
 	// https://github.com/opencontainers/runc/issues/2425.
-	for i := 0; i < 300; i++ {
+	for range 300 {
 		var stdout bytes.Buffer
 
 		parent, child, err := utils.NewSockPair("console")

libcontainer/integration/update_test.go

@@ -60,7 +60,7 @@ func testUpdateDevices(t *testing.T, systemd bool) {
 	}
 	defaultDevices := config.Cgroups.Resources.Devices
 
-	for i := 0; i < 300; i++ {
+	for i := range 300 {
 		// Check the access
 		buf.Reset()
 		err = container.Run(devCheck)

libcontainer/process_linux.go

@@ -877,7 +877,7 @@ func getPipeFds(pid int) ([]string, error) {
 	fds := make([]string, 3)
 
 	dirPath := filepath.Join("/proc", strconv.Itoa(pid), "/fd")
-	for i := 0; i < 3; i++ {
+	for i := range 3 {
 		// XXX: This breaks if the path is not a valid symlink (which can
 		//      happen in certain particularly unlucky mount namespace setups).
 		f := filepath.Join(dirPath, strconv.Itoa(i))

libcontainer/rootfs_linux.go

@@ -878,7 +878,7 @@ func reOpenDevNull() error {
 	if err := unix.Fstat(int(file.Fd()), &devNullStat); err != nil {
 		return &os.PathError{Op: "fstat", Path: file.Name(), Err: err}
 	}
-	for fd := 0; fd < 3; fd++ {
+	for fd := range 3 {
 		if err := unix.Fstat(fd, &stat); err != nil {
 			return &os.PathError{Op: "fstat", Path: "fd " + strconv.Itoa(fd), Err: err}
 		}
@@ -1211,7 +1211,7 @@ func remountReadonly(m *configs.Mount) error {
 		dest  = m.Destination
 		flags = m.Flags
 	)
-	for i := 0; i < 5; i++ {
+	for range 5 {
 		// There is a special case in the kernel for
 		// MS_REMOUNT | MS_BIND, which allows us to change only the
 		// flags even as an unprivileged user (i.e. user namespace)

libcontainer/specconv/spec_linux.go

@@ -626,7 +626,7 @@ func checkPropertyName(s string) error {
 	}
 	// Check ASCII characters rather than Unicode runes,
 	// so we have to use indexes rather than range.
-	for i := 0; i < len(s); i++ {
+	for i := range len(s) {
 		ch := s[i]
 		if (ch >= 'A' && ch <= 'Z') || (ch >= 'a' && ch <= 'z') {
 			continue