*: fmt.Errorf: use %w when appropriate

This should result in no change when the error is printed, but make the
errors returned unwrappable, meaning errors.As and errors.Is will work.

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

exec.go

@@ -101,7 +101,7 @@ following will output a list of processes running in the container:
 		if err == nil {
 			os.Exit(status)
 		}
-		return fmt.Errorf("exec failed: %v", err)
+		return fmt.Errorf("exec failed: %w", err)
 	},
 	SkipArgReorder: true,
 }
@@ -212,13 +212,13 @@ func getProcess(context *cli.Context, bundle string) (*specs.Process, error) {
 		if len(u) > 1 {
 			gid, err := strconv.Atoi(u[1])
 			if err != nil {
-				return nil, fmt.Errorf("parsing %s as int for gid failed: %v", u[1], err)
+				return nil, fmt.Errorf("parsing %s as int for gid failed: %w", u[1], err)
 			}
 			p.User.GID = uint32(gid)
 		}
 		uid, err := strconv.Atoi(u[0])
 		if err != nil {
-			return nil, fmt.Errorf("parsing %s as int for uid failed: %v", u[0], err)
+			return nil, fmt.Errorf("parsing %s as int for uid failed: %w", u[0], err)
 		}
 		p.User.UID = uint32(uid)
 	}

libcontainer/apparmor/apparmor_linux.go

@@ -52,7 +52,7 @@ func setProcAttr(attr, value string) error {
 // changeOnExec reimplements aa_change_onexec from libapparmor in Go
 func changeOnExec(name string) error {
 	if err := setProcAttr("exec", "exec "+name); err != nil {
-		return fmt.Errorf("apparmor failed to apply profile: %s", err)
+		return fmt.Errorf("apparmor failed to apply profile: %w", err)
 	}
 	return nil
 }

libcontainer/cgroups/utils.go

@@ -376,7 +376,7 @@ func WriteCgroupProc(dir string, pid int) error {
 
 	file, err := OpenFile(dir, CgroupProcesses, os.O_WRONLY)
 	if err != nil {
-		return fmt.Errorf("failed to write %v to %v: %v", pid, CgroupProcesses, err)
+		return fmt.Errorf("failed to write %v to %v: %w", pid, CgroupProcesses, err)
 	}
 	defer file.Close()
 
@@ -393,7 +393,7 @@ func WriteCgroupProc(dir string, pid int) error {
 			continue
 		}
 
-		return fmt.Errorf("failed to write %v to %v: %v", pid, CgroupProcesses, err)
+		return fmt.Errorf("failed to write %v to %v: %w", pid, CgroupProcesses, err)
 	}
 	return err
 }

libcontainer/configs/config.go

@@ -375,7 +375,7 @@ func (c Command) Run(s *specs.State) error {
 	go func() {
 		err := cmd.Wait()
 		if err != nil {
-			err = fmt.Errorf("error running hook: %v, stdout: %s, stderr: %s", err, stdout.String(), stderr.String())
+			err = fmt.Errorf("error running hook: %w, stdout: %s, stderr: %s", err, stdout.String(), stderr.String())
 		}
 		errC <- err
 	}()

libcontainer/configs/validate/validator.go

@@ -268,10 +268,10 @@ func isHostNetNS(path string) (bool, error) {
 	var st1, st2 unix.Stat_t
 
 	if err := unix.Stat(currentProcessNetns, &st1); err != nil {
-		return false, fmt.Errorf("unable to stat %q: %s", currentProcessNetns, err)
+		return false, &os.PathError{Op: "stat", Path: currentProcessNetns, Err: err}
 	}
 	if err := unix.Stat(path, &st2); err != nil {
-		return false, fmt.Errorf("unable to stat %q: %s", path, err)
+		return false, &os.PathError{Op: "stat", Path: path, Err: err}
 	}
 
 	return (st1.Dev == st2.Dev) && (st1.Ino == st2.Ino), nil

libcontainer/container_linux.go

@@ -478,7 +478,7 @@ func (c *linuxContainer) newParentProcess(p *Process) (parentProcess, error) {
 
 	parentLogPipe, childLogPipe, err := os.Pipe()
 	if err != nil {
-		return nil, fmt.Errorf("Unable to create the log pipe:  %s", err)
+		return nil, fmt.Errorf("unable to create log pipe: %w", err)
 	}
 	logFilePair := filePair{parentLogPipe, childLogPipe}
 
@@ -771,7 +771,7 @@ func (c *linuxContainer) checkCriuVersion(minVersion int) error {
 	var err error
 	c.criuVersion, err = criu.GetCriuVersion()
 	if err != nil {
-		return fmt.Errorf("CRIU version check failed: %s", err)
+		return fmt.Errorf("CRIU version check failed: %w", err)
 	}
 
 	return compareCriuVersion(c.criuVersion, minVersion)

libcontainer/factory_linux.go

@@ -396,7 +396,7 @@ func (l *LinuxFactory) StartInitialization() (err error) {
 	}()
 	defer func() {
 		if e := recover(); e != nil {
-			err = fmt.Errorf("panic from initialization: %v, %v", e, string(debug.Stack()))
+			err = fmt.Errorf("panic from initialization: %w, %v", e, string(debug.Stack()))
 		}
 	}()
 

libcontainer/init_linux.go

@@ -158,7 +158,7 @@ func finalizeNamespace(config *initConfig) error {
 			// to the directory, but the user running runc does not.
 			// This is useful in cases where the cwd is also a volume that's been chowned to the container user.
 		default:
-			return fmt.Errorf("chdir to cwd (%q) set in config.json failed: %v", config.Cwd, err)
+			return fmt.Errorf("chdir to cwd (%q) set in config.json failed: %w", config.Cwd, err)
 		}
 	}
 
@@ -186,7 +186,7 @@ func finalizeNamespace(config *initConfig) error {
 	// Change working directory AFTER the user has been set up, if we haven't done it yet.
 	if doChdir {
 		if err := unix.Chdir(config.Cwd); err != nil {
-			return fmt.Errorf("chdir to cwd (%q) set in config.json failed: %v", config.Cwd, err)
+			return fmt.Errorf("chdir to cwd (%q) set in config.json failed: %w", config.Cwd, err)
 		}
 	}
 	if err := system.ClearKeepCaps(); err != nil {
@@ -457,7 +457,7 @@ func setupRoute(config *configs.Config) error {
 func setupRlimits(limits []configs.Rlimit, pid int) error {
 	for _, rlimit := range limits {
 		if err := system.Prlimit(pid, rlimit.Type, unix.Rlimit{Max: rlimit.Hard, Cur: rlimit.Soft}); err != nil {
-			return fmt.Errorf("error setting rlimit type %v: %v", rlimit.Type, err)
+			return fmt.Errorf("error setting rlimit type %v: %w", rlimit.Type, err)
 		}
 	}
 	return nil

libcontainer/integration/utils_test.go

@@ -35,7 +35,7 @@ func init() {
 	// Call it to make sure images are downloaded, and to get the paths.
 	out, err := exec.Command(getImages).CombinedOutput()
 	if err != nil {
-		panic(fmt.Errorf("getImages error %s (output: %s)", err, out))
+		panic(fmt.Errorf("getImages error %w (output: %s)", err, out))
 	}
 	// Extract the value of BUSYBOX_IMAGE.
 	found := regexp.MustCompile(`(?m)^BUSYBOX_IMAGE=(.*)$`).FindSubmatchIndex(out)
@@ -145,7 +145,7 @@ func remove(dir string) {
 func copyBusybox(dest string) error {
 	out, err := exec.Command("sh", "-c", fmt.Sprintf("tar --exclude './dev/*' -C %q -xf %q", dest, busyboxTar)).CombinedOutput()
 	if err != nil {
-		return fmt.Errorf("untar error %q: %q", err, out)
+		return fmt.Errorf("untar error %w: %q", err, out)
 	}
 	return nil
 }

libcontainer/intelrdt/intelrdt.go

@@ -414,7 +414,7 @@ func writeFile(dir, file, data string) error {
 		return fmt.Errorf("no such directory for %s", file)
 	}
 	if err := ioutil.WriteFile(filepath.Join(dir, file), []byte(data+"\n"), 0o600); err != nil {
-		return fmt.Errorf("failed to write %v: %v", data, err)
+		return fmt.Errorf("failed to write %v: %w", data, err)
 	}
 	return nil
 }
@@ -521,7 +521,7 @@ 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 {
-			return fmt.Errorf("failed to write %v: %v", pid, err)
+			return fmt.Errorf("failed to write %v: %w", pid, err)
 		}
 	}
 	return nil

libcontainer/rootfs_linux.go

@@ -208,7 +208,7 @@ func mountCmd(cmd configs.Command) error {
 	command.Env = cmd.Env
 	command.Dir = cmd.Dir
 	if out, err := command.CombinedOutput(); err != nil {
-		return fmt.Errorf("%#v failed: %s: %v", cmd, string(out), err)
+		return fmt.Errorf("%#v failed: %s: %w", cmd, string(out), err)
 	}
 	return nil
 }

libcontainer/seccomp/seccomp_linux.go

@@ -43,23 +43,23 @@ func InitSeccomp(config *configs.Seccomp) error {
 
 	filter, err := libseccomp.NewFilter(defaultAction)
 	if err != nil {
-		return fmt.Errorf("error creating filter: %s", err)
+		return fmt.Errorf("error creating filter: %w", err)
 	}
 
 	// Add extra architectures
 	for _, arch := range config.Architectures {
 		scmpArch, err := libseccomp.GetArchFromString(arch)
 		if err != nil {
-			return fmt.Errorf("error validating Seccomp architecture: %s", err)
+			return fmt.Errorf("error validating Seccomp architecture: %w", err)
 		}
 		if err := filter.AddArch(scmpArch); err != nil {
-			return fmt.Errorf("error adding architecture to seccomp filter: %s", err)
+			return fmt.Errorf("error adding architecture to seccomp filter: %w", err)
 		}
 	}
 
 	// Unset no new privs bit
 	if err := filter.SetNoNewPrivsBit(false); err != nil {
-		return fmt.Errorf("error setting no new privileges: %s", err)
+		return fmt.Errorf("error setting no new privileges: %w", err)
 	}
 
 	// Add a rule for each syscall
@@ -72,7 +72,7 @@ func InitSeccomp(config *configs.Seccomp) error {
 		}
 	}
 	if err := patchbpf.PatchAndLoad(config, filter); err != nil {
-		return fmt.Errorf("error loading seccomp filter into kernel: %s", err)
+		return fmt.Errorf("error loading seccomp filter into kernel: %w", err)
 	}
 	return nil
 }
@@ -161,13 +161,13 @@ func matchCall(filter *libseccomp.ScmpFilter, call *configs.Syscall) error {
 	// Convert the call's action to the libseccomp equivalent
 	callAct, err := getAction(call.Action, call.ErrnoRet)
 	if err != nil {
-		return fmt.Errorf("action in seccomp profile is invalid: %s", err)
+		return fmt.Errorf("action in seccomp profile is invalid: %w", err)
 	}
 
 	// Unconditional match - just add the rule
 	if len(call.Args) == 0 {
 		if err := filter.AddRule(callNum, callAct); err != nil {
-			return fmt.Errorf("error adding seccomp filter rule for syscall %s: %s", call.Name, err)
+			return fmt.Errorf("error adding seccomp filter rule for syscall %s: %w", call.Name, err)
 		}
 	} else {
 		// If two or more arguments have the same condition,
@@ -178,7 +178,7 @@ func matchCall(filter *libseccomp.ScmpFilter, call *configs.Syscall) error {
 		for _, cond := range call.Args {
 			newCond, err := getCondition(cond)
 			if err != nil {
-				return fmt.Errorf("error creating seccomp syscall condition for syscall %s: %s", call.Name, err)
+				return fmt.Errorf("error creating seccomp syscall condition for syscall %s: %w", call.Name, err)
 			}
 
 			argCounts[cond.Index] += 1
@@ -201,14 +201,14 @@ func matchCall(filter *libseccomp.ScmpFilter, call *configs.Syscall) error {
 				condArr := []libseccomp.ScmpCondition{cond}
 
 				if err := filter.AddRuleConditional(callNum, callAct, condArr); err != nil {
-					return fmt.Errorf("error adding seccomp rule for syscall %s: %s", call.Name, err)
+					return fmt.Errorf("error adding seccomp rule for syscall %s: %w", call.Name, err)
 				}
 			}
 		} else {
 			// No conditions share same argument
 			// Use new, proper behavior
 			if err := filter.AddRuleConditional(callNum, callAct, conditions); err != nil {
-				return fmt.Errorf("error adding seccomp rule for syscall %s: %s", call.Name, err)
+				return fmt.Errorf("error adding seccomp rule for syscall %s: %w", call.Name, err)
 			}
 		}
 	}

libcontainer/specconv/spec_linux.go

@@ -410,13 +410,13 @@ func initSystemdProps(spec *specs.Spec) ([]systemdDbus.Property, error) {
 		}
 		value, err := dbus.ParseVariant(v, dbus.Signature{})
 		if err != nil {
-			return nil, fmt.Errorf("Annotation %s=%s value parse error: %v", k, v, err)
+			return nil, fmt.Errorf("Annotation %s=%s value parse error: %w", k, v, err)
 		}
 		if isSecSuffix(name) {
 			name = strings.TrimSuffix(name, "Sec") + "USec"
 			value, err = convertSecToUSec(value)
 			if err != nil {
-				return nil, fmt.Errorf("Annotation %s=%s value parse error: %v", k, v, err)
+				return nil, fmt.Errorf("Annotation %s=%s value parse error: %w", k, v, err)
 			}
 		}
 		sp = append(sp, systemdDbus.Property{Name: name, Value: value})

libcontainer/sync.go

@@ -48,14 +48,14 @@ func readSync(pipe io.Reader, expected syncType) error {
 		if err == io.EOF {
 			return errors.New("parent closed synchronisation channel")
 		}
-		return fmt.Errorf("failed reading error from parent: %v", err)
+		return fmt.Errorf("failed reading error from parent: %w", err)
 	}
 
 	if procSync.Type == procError {
 		var ierr genericError
 
 		if err := json.NewDecoder(pipe).Decode(&ierr); err != nil {
-			return fmt.Errorf("failed reading error from parent: %v", err)
+			return fmt.Errorf("failed reading error from parent: %w", err)
 		}
 
 		return &ierr

libcontainer/user/user.go

@@ -305,7 +305,7 @@ func GetExecUser(userSpec string, defaults *ExecUser, passwd, group io.Reader) (
 		if userArg == "" {
 			userArg = strconv.Itoa(user.Uid)
 		}
-		return nil, fmt.Errorf("unable to find user %s: %v", userArg, err)
+		return nil, fmt.Errorf("unable to find user %s: %w", userArg, err)
 	}
 
 	var matchedUserName string
@@ -321,7 +321,7 @@ func GetExecUser(userSpec string, defaults *ExecUser, passwd, group io.Reader) (
 
 		if uidErr != nil {
 			// Not numeric.
-			return nil, fmt.Errorf("unable to find user %s: %v", userArg, ErrNoPasswdEntries)
+			return nil, fmt.Errorf("unable to find user %s: %w", userArg, ErrNoPasswdEntries)
 		}
 		user.Uid = uidArg
 
@@ -356,7 +356,7 @@ func GetExecUser(userSpec string, defaults *ExecUser, passwd, group io.Reader) (
 			return g.Name == groupArg
 		})
 		if err != nil && group != nil {
-			return nil, fmt.Errorf("unable to find groups for spec %v: %v", matchedUserName, err)
+			return nil, fmt.Errorf("unable to find groups for spec %v: %w", matchedUserName, err)
 		}
 
 		// Only start modifying user.Gid if it is in explicit form.
@@ -370,7 +370,7 @@ func GetExecUser(userSpec string, defaults *ExecUser, passwd, group io.Reader) (
 
 				if gidErr != nil {
 					// Not numeric.
-					return nil, fmt.Errorf("unable to find group %s: %v", groupArg, ErrNoGroupEntries)
+					return nil, fmt.Errorf("unable to find group %s: %w", groupArg, ErrNoGroupEntries)
 				}
 				user.Gid = gidArg
 
@@ -411,7 +411,7 @@ func GetAdditionalGroups(additionalGroups []string, group io.Reader) ([]int, err
 			return false
 		})
 		if err != nil {
-			return nil, fmt.Errorf("Unable to find additional groups %v: %v", additionalGroups, err)
+			return nil, fmt.Errorf("Unable to find additional groups %v: %w", additionalGroups, err)
 		}
 	}
 
@@ -434,7 +434,8 @@ func GetAdditionalGroups(additionalGroups []string, group io.Reader) ([]int, err
 		if !found {
 			gid, err := strconv.ParseInt(ag, 10, 64)
 			if err != nil {
-				return nil, fmt.Errorf("Unable to find group %s", ag)
+				// Not a numeric ID either.
+				return nil, fmt.Errorf("Unable to find group %s: %w", ag, ErrNoGroupEntries)
 			}
 			// Ensure gid is inside gid range.
 			if gid < minID || gid > maxID {

libcontainer/utils/utils.go

@@ -11,7 +11,7 @@ import (
 	"strings"
 	"unsafe"
 
-	"github.com/cyphar/filepath-securejoin"
+	securejoin "github.com/cyphar/filepath-securejoin"
 	"golang.org/x/sys/unix"
 )
 
@@ -120,7 +120,7 @@ func WithProcfd(root, unsafePath string, fn func(procfd string) error) error {
 	unsafePath = stripRoot(root, unsafePath)
 	path, err := securejoin.SecureJoin(root, unsafePath)
 	if err != nil {
-		return fmt.Errorf("resolving path inside rootfs failed: %v", err)
+		return fmt.Errorf("resolving path inside rootfs failed: %w", err)
 	}
 
 	// Open the target path.

libcontainer/utils/utils_unix.go

@@ -14,7 +14,7 @@ import (
 func EnsureProcHandle(fh *os.File) error {
 	var buf unix.Statfs_t
 	if err := unix.Fstatfs(int(fh.Fd()), &buf); err != nil {
-		return fmt.Errorf("ensure %s is on procfs: %v", fh.Name(), err)
+		return fmt.Errorf("ensure %s is on procfs: %w", fh.Name(), err)
 	}
 	if buf.Type != unix.PROC_SUPER_MAGIC {
 		return fmt.Errorf("%s is not on procfs", fh.Name())

ps.go

@@ -68,7 +68,7 @@ var psCommand = cli.Command{
 		cmd := exec.Command("ps", psArgs...)
 		output, err := cmd.CombinedOutput()
 		if err != nil {
-			return fmt.Errorf("%s: %s", err, output)
+			return fmt.Errorf("%w: %s", err, output)
 		}
 
 		lines := strings.Split(string(output), "\n")
@@ -85,7 +85,7 @@ var psCommand = cli.Command{
 			fields := strings.Fields(line)
 			p, err := strconv.Atoi(fields[pidIndex])
 			if err != nil {
-				return fmt.Errorf("unexpected pid '%s': %s", fields[pidIndex], err)
+				return fmt.Errorf("unable to parse pid: %w", err)
 			}
 
 			for _, pid := range pids {

tty.go

@@ -136,7 +136,7 @@ func (t *tty) recvtty(process *libcontainer.Process, socket *os.File) (Err error
 
 	// Set raw mode for the controlling terminal.
 	if err := t.hostConsole.SetRaw(); err != nil {
-		return fmt.Errorf("failed to set the terminal from the stdin: %v", err)
+		return fmt.Errorf("failed to set the terminal from the stdin: %w", err)
 	}
 	go handleInterrupt(t.hostConsole)
 

update.go

@@ -205,7 +205,7 @@ other options are ignored.
 					var err error
 					*pair.dest, err = strconv.ParseUint(val, 10, 64)
 					if err != nil {
-						return fmt.Errorf("invalid value for %s: %s", pair.opt, err)
+						return fmt.Errorf("invalid value for %s: %w", pair.opt, err)
 					}
 				}
 			}
@@ -221,7 +221,7 @@ other options are ignored.
 					var err error
 					*pair.dest, err = strconv.ParseInt(val, 10, 64)
 					if err != nil {
-						return fmt.Errorf("invalid value for %s: %s", pair.opt, err)
+						return fmt.Errorf("invalid value for %s: %w", pair.opt, err)
 					}
 				}
 			}
@@ -241,7 +241,7 @@ other options are ignored.
 					if val != "-1" {
 						v, err = units.RAMInBytes(val)
 						if err != nil {
-							return fmt.Errorf("invalid value for %s: %s", pair.opt, err)
+							return fmt.Errorf("invalid value for %s: %w", pair.opt, err)
 						}
 					} else {
 						v = -1