Remove io/ioutil use

See https://golang.org/doc/go1.16#ioutil

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

contrib/cmd/recvtty/recvtty.go

@@ -20,7 +20,6 @@ import (
 	"errors"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"net"
 	"os"
 	"strings"
@@ -177,7 +176,7 @@ func handleNull(path string) error {
 				return
 			}
 
-			_, _ = io.Copy(ioutil.Discard, master)
+			_, _ = io.Copy(io.Discard, master)
 		}(conn)
 	}
 }
@@ -225,7 +224,7 @@ func main() {
 		pidPath := ctx.String("pid-file")
 		if pidPath != "" {
 			pid := fmt.Sprintf("%d\n", os.Getpid())
-			if err := ioutil.WriteFile(pidPath, []byte(pid), 0o644); err != nil {
+			if err := os.WriteFile(pidPath, []byte(pid), 0o644); err != nil {
 				return err
 			}
 		}

contrib/cmd/seccompagent/seccompagent.go

@@ -9,7 +9,6 @@ import (
 	"errors"
 	"flag"
 	"fmt"
-	"io/ioutil"
 	"net"
 	"os"
 	"path/filepath"
@@ -246,7 +245,7 @@ func main() {
 
 	if pidFile != "" {
 		pid := fmt.Sprintf("%d", os.Getpid())
-		if err := ioutil.WriteFile(pidFile, []byte(pid), 0o644); err != nil {
+		if err := os.WriteFile(pidFile, []byte(pid), 0o644); err != nil {
 			logrus.Fatalf("Cannot write pid file: %v", err)
 		}
 	}

libcontainer/apparmor/apparmor_linux.go

@@ -3,7 +3,6 @@ package apparmor
 import (
 	"errors"
 	"fmt"
-	"io/ioutil"
 	"os"
 	"sync"
 
@@ -19,7 +18,7 @@ var (
 func isEnabled() bool {
 	checkAppArmor.Do(func() {
 		if _, err := os.Stat("/sys/kernel/security/apparmor"); err == nil {
-			buf, err := ioutil.ReadFile("/sys/module/apparmor/parameters/enabled")
+			buf, err := os.ReadFile("/sys/module/apparmor/parameters/enabled")
 			appArmorEnabled = err == nil && len(buf) > 1 && buf[0] == 'Y'
 		}
 	})

libcontainer/capabilities/capabilities_linux_test.go

@@ -1,7 +1,7 @@
 package capabilities
 
 import (
-	"io/ioutil"
+	"io"
 	"os"
 	"testing"
 
@@ -24,7 +24,7 @@ func TestNew(t *testing.T) {
 	hook := test.NewGlobal()
 	defer hook.Reset()
 
-	logrus.SetOutput(ioutil.Discard)
+	logrus.SetOutput(io.Discard)
 	caps, err := New(&conf)
 	logrus.SetOutput(os.Stderr)
 

libcontainer/cgroups/fs/blkio_test.go

@@ -258,7 +258,7 @@ func TestBlkioSetMultipleWeightDevice(t *testing.T) {
 
 	wd1 := configs.NewWeightDevice(8, 0, 500, 0)
 	wd2 := configs.NewWeightDevice(8, 16, 500, 0)
-	// we cannot actually set and check both because normal ioutil.WriteFile
+	// we cannot actually set and check both because normal os.WriteFile
 	// when writing to cgroup file will overwrite the whole file content instead
 	// of updating it as the kernel is doing. Just check the second device
 	// is present will suffice for the test to ensure multiple writes are done.

libcontainer/cgroups/fs2/io_test.go

@@ -1,7 +1,7 @@
 package fs2
 
 import (
-	"io/ioutil"
+	"os"
 	"path/filepath"
 	"reflect"
 	"sort"
@@ -62,7 +62,7 @@ func TestStatIo(t *testing.T) {
 	fakeCgroupDir := t.TempDir()
 	statPath := filepath.Join(fakeCgroupDir, "io.stat")
 
-	if err := ioutil.WriteFile(statPath, []byte(exampleIoStatData), 0o644); err != nil {
+	if err := os.WriteFile(statPath, []byte(exampleIoStatData), 0o644); err != nil {
 		t.Fatal(err)
 	}
 

libcontainer/cgroups/fscommon/utils_test.go

@@ -1,7 +1,6 @@
 package fscommon
 
 import (
-	"io/ioutil"
 	"math"
 	"os"
 	"path/filepath"
@@ -27,7 +26,7 @@ func TestGetCgroupParamsInt(t *testing.T) {
 	tempFile := filepath.Join(tempDir, cgroupFile)
 
 	// Success.
-	if err := ioutil.WriteFile(tempFile, []byte(floatString), 0o755); err != nil {
+	if err := os.WriteFile(tempFile, []byte(floatString), 0o755); err != nil {
 		t.Fatal(err)
 	}
 	value, err := GetCgroupParamUint(tempDir, cgroupFile)
@@ -38,7 +37,7 @@ func TestGetCgroupParamsInt(t *testing.T) {
 	}
 
 	// Success with new line.
-	err = ioutil.WriteFile(tempFile, []byte(floatString+"\n"), 0o755)
+	err = os.WriteFile(tempFile, []byte(floatString+"\n"), 0o755)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -50,7 +49,7 @@ func TestGetCgroupParamsInt(t *testing.T) {
 	}
 
 	// Success with negative values
-	err = ioutil.WriteFile(tempFile, []byte("-12345"), 0o755)
+	err = os.WriteFile(tempFile, []byte("-12345"), 0o755)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -63,7 +62,7 @@ func TestGetCgroupParamsInt(t *testing.T) {
 
 	// Success with negative values lesser than min int64
 	s := strconv.FormatFloat(math.MinInt64, 'f', -1, 64)
-	err = ioutil.WriteFile(tempFile, []byte(s), 0o755)
+	err = os.WriteFile(tempFile, []byte(s), 0o755)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -75,7 +74,7 @@ func TestGetCgroupParamsInt(t *testing.T) {
 	}
 
 	// Not a float.
-	err = ioutil.WriteFile(tempFile, []byte("not-a-float"), 0o755)
+	err = os.WriteFile(tempFile, []byte("not-a-float"), 0o755)
 	if err != nil {
 		t.Fatal(err)
 	}

libcontainer/cgroups/utils.go

@@ -5,7 +5,6 @@ import (
 	"errors"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"strconv"
@@ -243,7 +242,7 @@ func RemovePath(path string) error {
 		return nil
 	}
 
-	infos, err := ioutil.ReadDir(path)
+	infos, err := os.ReadDir(path)
 	if err != nil {
 		if os.IsNotExist(err) {
 			err = nil

libcontainer/configs/config_test.go

@@ -3,7 +3,6 @@ package configs_test
 import (
 	"encoding/json"
 	"fmt"
-	"io/ioutil"
 	"os"
 	"reflect"
 	"testing"
@@ -190,7 +189,7 @@ exit 0
 	verifyCommand := fmt.Sprintf(verifyCommandTemplate, stateJson)
 	filename := "/tmp/runc-hooktest.sh"
 	os.Remove(filename)
-	if err := ioutil.WriteFile(filename, []byte(verifyCommand), 0o700); err != nil {
+	if err := os.WriteFile(filename, []byte(verifyCommand), 0o700); err != nil {
 		t.Fatalf("Failed to create tmp file: %v", err)
 	}
 	defer os.Remove(filename)

libcontainer/container_linux.go

@@ -6,7 +6,6 @@ import (
 	"errors"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"net"
 	"os"
 	"os/exec"
@@ -286,7 +285,7 @@ func (c *linuxContainer) exec() error {
 }
 
 func readFromExecFifo(execFifo io.Reader) error {
-	data, err := ioutil.ReadAll(execFifo)
+	data, err := io.ReadAll(execFifo)
 	if err != nil {
 		return err
 	}
@@ -1151,7 +1150,7 @@ func (c *linuxContainer) Checkpoint(criuOpts *CriuOpts) error {
 			return err
 		}
 
-		err = ioutil.WriteFile(filepath.Join(criuOpts.ImagesDirectory, descriptorsFilename), fdsJSON, 0o600)
+		err = os.WriteFile(filepath.Join(criuOpts.ImagesDirectory, descriptorsFilename), fdsJSON, 0o600)
 		if err != nil {
 			return err
 		}
@@ -1455,7 +1454,7 @@ func (c *linuxContainer) Restore(process *Process, criuOpts *CriuOpts) error {
 		fds    []string
 		fdJSON []byte
 	)
-	if fdJSON, err = ioutil.ReadFile(filepath.Join(criuOpts.ImagesDirectory, descriptorsFilename)); err != nil {
+	if fdJSON, err = os.ReadFile(filepath.Join(criuOpts.ImagesDirectory, descriptorsFilename)); err != nil {
 		return err
 	}
 
@@ -1850,7 +1849,7 @@ func (c *linuxContainer) updateState(process parentProcess) (*State, error) {
 }
 
 func (c *linuxContainer) saveState(s *State) (retErr error) {
-	tmpFile, err := ioutil.TempFile(c.root, "state-")
+	tmpFile, err := os.CreateTemp(c.root, "state-")
 	if err != nil {
 		return err
 	}

libcontainer/devices/device_unix.go

@@ -5,7 +5,6 @@ package devices
 
 import (
 	"errors"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 
@@ -18,7 +17,7 @@ var ErrNotADevice = errors.New("not a device node")
 // Testing dependencies
 var (
 	unixLstat = unix.Lstat
-	ioutilReadDir = ioutil.ReadDir
+	osReadDir = os.ReadDir
 )
 
 func mkDev(d *Rule) (uint64, error) {
@@ -77,7 +76,7 @@ func HostDevices() ([]*Device, error) {
 // GetDevices recursively traverses a directory specified by path
 // and returns all devices found there.
 func GetDevices(path string) ([]*Device, error) {
-	files, err := ioutilReadDir(path)
+	files, err := osReadDir(path)
 	if err != nil {
 		return nil, err
 	}

libcontainer/devices/device_unix_go116_test.go

@@ -0,0 +1,39 @@
+//go:build !go1.17
+// +build !go1.17
+
+package devices
+
+import "io/fs"
+
+// The following code is adapted from go1.17.1/src/io/fs/readdir.go
+// to compensate for the lack of fs.FileInfoToDirEntry in Go 1.16.
+
+// dirInfo is a DirEntry based on a FileInfo.
+type dirInfo struct {
+	fileInfo fs.FileInfo
+}
+
+func (di dirInfo) IsDir() bool {
+	return di.fileInfo.IsDir()
+}
+
+func (di dirInfo) Type() fs.FileMode {
+	return di.fileInfo.Mode().Type()
+}
+
+func (di dirInfo) Info() (fs.FileInfo, error) {
+	return di.fileInfo, nil
+}
+
+func (di dirInfo) Name() string {
+	return di.fileInfo.Name()
+}
+
+// fileInfoToDirEntry returns a DirEntry that returns information from info.
+// If info is nil, FileInfoToDirEntry returns nil.
+func fileInfoToDirEntry(info fs.FileInfo) fs.DirEntry {
+	if info == nil {
+		return nil
+	}
+	return dirInfo{fileInfo: info}
+}

libcontainer/devices/device_unix_go117_test.go

@@ -0,0 +1,8 @@
+//go:build go1.17
+// +build go1.17
+
+package devices
+
+import "io/fs"
+
+var fileInfoToDirEntry = fs.FileInfoToDirEntry

libcontainer/devices/device_unix_test.go

@@ -5,7 +5,7 @@ package devices
 
 import (
 	"errors"
-	"io/ioutil"
+	"io/fs"
 	"os"
 	"testing"
 
@@ -14,7 +14,7 @@ import (
 
 func cleanupTest() {
 	unixLstat = unix.Lstat
-	ioutilReadDir = ioutil.ReadDir
+	osReadDir = os.ReadDir
 }
 
 func TestDeviceFromPathLstatFailure(t *testing.T) {
@@ -35,8 +35,8 @@ func TestDeviceFromPathLstatFailure(t *testing.T) {
 func TestHostDevicesIoutilReadDirFailure(t *testing.T) {
 	testError := errors.New("test error")
 
-	// Override ioutil.ReadDir to inject error.
-	ioutilReadDir = func(dirname string) ([]os.FileInfo, error) {
+	// Override os.ReadDir to inject error.
+	osReadDir = func(dirname string) ([]fs.DirEntry, error) {
 		return nil, testError
 	}
 	defer cleanupTest()
@@ -51,8 +51,8 @@ func TestHostDevicesIoutilReadDirDeepFailure(t *testing.T) {
 	testError := errors.New("test error")
 	called := false
 
-	// Override ioutil.ReadDir to inject error after the first call.
-	ioutilReadDir = func(dirname string) ([]os.FileInfo, error) {
+	// Override os.ReadDir to inject error after the first call.
+	osReadDir = func(dirname string) ([]fs.DirEntry, error) {
 		if called {
 			return nil, testError
 		}
@@ -64,7 +64,7 @@ func TestHostDevicesIoutilReadDirDeepFailure(t *testing.T) {
 			t.Fatalf("Unexpected error %v", err)
 		}
 
-		return []os.FileInfo{fi}, nil
+		return []fs.DirEntry{fileInfoToDirEntry(fi)}, nil
 	}
 	defer cleanupTest()
 

libcontainer/init_linux.go

@@ -6,7 +6,6 @@ import (
 	"errors"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"net"
 	"os"
 	"strings"
@@ -358,7 +357,7 @@ func setupUser(config *initConfig) error {
 		return err
 	}
 
-	setgroups, err := ioutil.ReadFile("/proc/self/setgroups")
+	setgroups, err := os.ReadFile("/proc/self/setgroups")
 	if err != nil && !os.IsNotExist(err) {
 		return err
 	}

libcontainer/integration/exec_test.go

@@ -4,7 +4,6 @@ import (
 	"bytes"
 	"encoding/json"
 	"fmt"
-	"io/ioutil"
 	"os"
 	"os/exec"
 	"path/filepath"
@@ -879,7 +878,7 @@ func TestMountCmds(t *testing.T) {
 	// Wait for process
 	waitProcess(&pconfig, t)
 
-	entries, err := ioutil.ReadDir(tmpDir)
+	entries, err := os.ReadDir(tmpDir)
 	ok(t, err)
 	expected := []string{"hello", "hello-backup", "world", "world-backup"}
 	for i, e := range entries {

libcontainer/intelrdt/intelrdt.go

@@ -6,7 +6,6 @@ import (
 	"errors"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"strconv"
@@ -367,7 +366,7 @@ func parseCpuInfoFile(path string) (cpuInfoFlags, error) {
 // Gets a single uint64 value from the specified file.
 func getIntelRdtParamUint(path, file string) (uint64, error) {
 	fileName := filepath.Join(path, file)
-	contents, err := ioutil.ReadFile(fileName)
+	contents, err := os.ReadFile(fileName)
 	if err != nil {
 		return 0, err
 	}
@@ -381,7 +380,7 @@ func getIntelRdtParamUint(path, file string) (uint64, error) {
 
 // Gets a string value from the specified file
 func getIntelRdtParamString(path, file string) (string, error) {
-	contents, err := ioutil.ReadFile(filepath.Join(path, file))
+	contents, err := os.ReadFile(filepath.Join(path, file))
 	if err != nil {
 		return "", err
 	}
@@ -393,7 +392,7 @@ func writeFile(dir, file, data string) error {
 	if dir == "" {
 		return fmt.Errorf("no such directory for %s", file)
 	}
-	if err := ioutil.WriteFile(filepath.Join(dir, file), []byte(data+"\n"), 0o600); err != nil {
+	if err := os.WriteFile(filepath.Join(dir, file), []byte(data+"\n"), 0o600); err != nil {
 		return newLastCmdError(fmt.Errorf("intelrdt: unable to write %v: %w", data, err))
 	}
 	return nil
@@ -488,7 +487,7 @@ func WriteIntelRdtTasks(dir string, pid int) error {
 
 	// Don't attach any pid if -1 is specified as a pid
 	if pid != -1 {
-		if err := ioutil.WriteFile(filepath.Join(dir, intelRdtTasks), []byte(strconv.Itoa(pid)), 0o600); err != nil {
+		if err := os.WriteFile(filepath.Join(dir, intelRdtTasks), []byte(strconv.Itoa(pid)), 0o600); err != nil {
 			return newLastCmdError(fmt.Errorf("intelrdt: unable to add pid %d: %w", pid, err))
 		}
 	}

libcontainer/intelrdt/monitoring.go

@@ -3,7 +3,6 @@ package intelrdt
 import (
 	"bufio"
 	"io"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 
@@ -49,7 +48,7 @@ func parseMonFeatures(reader io.Reader) (monFeatures, error) {
 }
 
 func getMonitoringStats(containerPath string, stats *Stats) error {
-	numaFiles, err := ioutil.ReadDir(filepath.Join(containerPath, "mon_data"))
+	numaFiles, err := os.ReadDir(filepath.Join(containerPath, "mon_data"))
 	if err != nil {
 		return err
 	}

libcontainer/intelrdt/monitoring_test.go

@@ -1,7 +1,6 @@
 package intelrdt
 
 import (
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"strconv"
@@ -51,7 +50,7 @@ func mockResctrlL3_MON(t *testing.T, NUMANodes []string, mocks map[string]uint64
 		}
 
 		for fileName, value := range mocks {
-			err := ioutil.WriteFile(filepath.Join(numaPath, fileName), []byte(strconv.FormatUint(value, 10)), 0o644)
+			err := os.WriteFile(filepath.Join(numaPath, fileName), []byte(strconv.FormatUint(value, 10)), 0o644)
 			if err != nil {
 				t.Fatal(err)
 			}

libcontainer/logs/logs_linux_test.go

@@ -3,7 +3,6 @@ package logs
 import (
 	"bytes"
 	"io"
-	"io/ioutil"
 	"os"
 	"testing"
 	"time"
@@ -93,7 +92,7 @@ func runLogForwarding(t *testing.T) *log {
 		logW.Close()
 	})
 
-	tempFile, err := ioutil.TempFile("", "")
+	tempFile, err := os.CreateTemp("", "")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -129,7 +128,7 @@ func truncateLogFile(t *testing.T, file *os.File) {
 // check checks that the file contains txt and does not contain notxt.
 func check(t *testing.T, l *log, txt, notxt string) {
 	t.Helper()
-	contents, err := ioutil.ReadFile(l.file.Name())
+	contents, err := os.ReadFile(l.file.Name())
 	if err != nil {
 		t.Fatal(err)
 	}

libcontainer/network_linux.go

@@ -3,7 +3,7 @@ package libcontainer
 import (
 	"bytes"
 	"fmt"
-	"io/ioutil"
+	"os"
 	"path/filepath"
 	"strconv"
 
@@ -73,7 +73,7 @@ func getNetworkInterfaceStats(interfaceName string) (*types.NetworkInterface, er
 
 // Reads the specified statistics available under /sys/class/net/<EthInterface>/statistics
 func readSysfsNetworkStats(ethInterface, statsFile string) (uint64, error) {
-	data, err := ioutil.ReadFile(filepath.Join("/sys/class/net", ethInterface, "statistics", statsFile))
+	data, err := os.ReadFile(filepath.Join("/sys/class/net", ethInterface, "statistics", statsFile))
 	if err != nil {
 		return 0, err
 	}

libcontainer/notify_linux.go

@@ -3,7 +3,6 @@ package libcontainer
 import (
 	"errors"
 	"fmt"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 
@@ -33,7 +32,7 @@ func registerMemoryEvent(cgDir string, evName string, arg string) (<-chan struct
 
 	eventControlPath := filepath.Join(cgDir, "cgroup.event_control")
 	data := fmt.Sprintf("%d %d %s", eventfd.Fd(), evFile.Fd(), arg)
-	if err := ioutil.WriteFile(eventControlPath, []byte(data), 0o700); err != nil {
+	if err := os.WriteFile(eventControlPath, []byte(data), 0o700); err != nil {
 		eventfd.Close()
 		evFile.Close()
 		return nil, err

libcontainer/notify_linux_test.go

@@ -3,7 +3,6 @@ package libcontainer
 import (
 	"encoding/binary"
 	"fmt"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"testing"
@@ -18,10 +17,10 @@ func testMemoryNotification(t *testing.T, evName string, notify notifyFunc, targ
 	memoryPath := t.TempDir()
 	evFile := filepath.Join(memoryPath, evName)
 	eventPath := filepath.Join(memoryPath, "cgroup.event_control")
-	if err := ioutil.WriteFile(evFile, []byte{}, 0o700); err != nil {
+	if err := os.WriteFile(evFile, []byte{}, 0o700); err != nil {
 		t.Fatal(err)
 	}
-	if err := ioutil.WriteFile(eventPath, []byte{}, 0o700); err != nil {
+	if err := os.WriteFile(eventPath, []byte{}, 0o700); err != nil {
 		t.Fatal(err)
 	}
 	ch, err := notify(memoryPath)
@@ -29,7 +28,7 @@ func testMemoryNotification(t *testing.T, evName string, notify notifyFunc, targ
 		t.Fatal("expected no error, got:", err)
 	}
 
-	data, err := ioutil.ReadFile(eventPath)
+	data, err := os.ReadFile(eventPath)
 	if err != nil {
 		t.Fatal("couldn't read event control file:", err)
 	}

libcontainer/rootfs_linux.go

@@ -4,7 +4,6 @@ import (
 	"errors"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"os"
 	"os/exec"
 	"path"
@@ -182,7 +181,7 @@ func finalizeRootfs(config *configs.Config) (err error) {
 
 // /tmp has to be mounted as private to allow MS_MOVE to work in all situations
 func prepareTmp(topTmpDir string) (string, error) {
-	tmpdir, err := ioutil.TempDir(topTmpDir, "runctop")
+	tmpdir, err := os.MkdirTemp(topTmpDir, "runctop")
 	if err != nil {
 		return "", err
 	}
@@ -337,7 +336,7 @@ func doTmpfsCopyUp(m *configs.Mount, rootfs, mountLabel string) (Err error) {
 		return fmt.Errorf("tmpcopyup: failed to setup tmpdir: %w", err)
 	}
 	defer cleanupTmp(tmpdir)
-	tmpDir, err := ioutil.TempDir(tmpdir, "runctmpdir")
+	tmpDir, err := os.MkdirTemp(tmpdir, "runctmpdir")
 	if err != nil {
 		return fmt.Errorf("tmpcopyup: failed to create tmpdir: %w", err)
 	}
@@ -1034,7 +1033,7 @@ func maskPath(path string, mountLabel string) error {
 // For e.g. net.ipv4.ip_forward translated to /proc/sys/net/ipv4/ip_forward.
 func writeSystemProperty(key, value string) error {
 	keyPath := strings.Replace(key, ".", "/", -1)
-	return ioutil.WriteFile(path.Join("/proc/sys", keyPath), []byte(value), 0o644)
+	return os.WriteFile(path.Join("/proc/sys", keyPath), []byte(value), 0o644)
 }
 
 func remount(m *configs.Mount, rootfs string) error {

libcontainer/system/proc.go

@@ -2,7 +2,7 @@ package system
 
 import (
 	"fmt"
-	"io/ioutil"
+	"os"
 	"path/filepath"
 	"strconv"
 	"strings"
@@ -67,7 +67,7 @@ type Stat_t struct {
 
 // Stat returns a Stat_t instance for the specified process.
 func Stat(pid int) (stat Stat_t, err error) {
-	bytes, err := ioutil.ReadFile(filepath.Join("/proc", strconv.Itoa(pid), "stat"))
+	bytes, err := os.ReadFile(filepath.Join("/proc", strconv.Itoa(pid), "stat"))
 	if err != nil {
 		return stat, err
 	}

libcontainer/utils/utils_unix.go

@@ -53,7 +53,7 @@ func CloseExecFrom(minFd int) error {
 		// Intentionally ignore errors from unix.CloseOnExec -- the cases where
 		// this might fail are basically file descriptors that have already
 		// been closed (including and especially the one that was created when
-		// ioutil.ReadDir did the "opendir" syscall).
+		// os.ReadDir did the "opendir" syscall).
 		unix.CloseOnExec(fd)
 	}
 	return nil

list.go

@@ -4,7 +4,6 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"syscall"
@@ -121,7 +120,7 @@ func getContainers(context *cli.Context) ([]containerState, error) {
 	if err != nil {
 		return nil, err
 	}
-	list, err := ioutil.ReadDir(absRoot)
+	list, err := os.ReadDir(absRoot)
 	if err != nil {
 		fatal(err)
 	}
@@ -129,11 +128,15 @@ func getContainers(context *cli.Context) ([]containerState, error) {
 	var s []containerState
 	for _, item := range list {
 		if item.IsDir() {
-			// This cast is safe on Linux.
-			stat := item.Sys().(*syscall.Stat_t)
-			owner, err := user.LookupUid(int(stat.Uid))
+			st, err := os.Stat(filepath.Join(absRoot, item.Name()))
 			if err != nil {
-				owner.Name = fmt.Sprintf("#%d", stat.Uid)
+				fatal(err)
+			}
+			// This cast is safe on Linux.
+			uid := st.Sys().(*syscall.Stat_t).Uid
+			owner, err := user.LookupUid(int(uid))
+			if err != nil {
+				owner.Name = fmt.Sprintf("#%d", uid)
 			}
 
 			container, err := factory.Load(item.Name())

spec.go

@@ -3,7 +3,6 @@ package main
 import (
 	"encoding/json"
 	"fmt"
-	"io/ioutil"
 	"os"
 
 	"github.com/opencontainers/runc/libcontainer/configs"
@@ -109,7 +108,7 @@ created by an unprivileged user.
 		if err != nil {
 			return err
 		}
-		return ioutil.WriteFile(specConfig, data, 0o666)
+		return os.WriteFile(specConfig, data, 0o666)
 	},
 }