Replace fmt.Errorf w/o %-style to errors.New

Using fmt.Errorf for errors that do not have %-style formatting
directives is an overkill. Switch to errors.New.

Found by

	git grep fmt.Errorf | grep -v ^vendor | grep -v '%'

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

contrib/cmd/recvtty/recvtty.go

@@ -17,6 +17,7 @@
 package main
 
 import (
+	"errors"
 	"fmt"
 	"io"
 	"io/ioutil"
@@ -88,7 +89,7 @@ func handleSingle(path string, noStdin bool) error {
 	// Get the fd of the connection.
 	unixconn, ok := conn.(*net.UnixConn)
 	if !ok {
-		return fmt.Errorf("failed to cast to unixconn")
+		return errors.New("failed to cast to unixconn")
 	}
 
 	socket, err := unixconn.File()
@@ -217,7 +218,7 @@ func main() {
 	app.Action = func(ctx *cli.Context) error {
 		args := ctx.Args()
 		if len(args) != 1 {
-			return fmt.Errorf("need to specify a single socket path")
+			return errors.New("need to specify a single socket path")
 		}
 		path := ctx.Args()[0]
 

exec.go

@@ -4,6 +4,7 @@ package main
 
 import (
 	"encoding/json"
+	"errors"
 	"fmt"
 	"os"
 	"strconv"
@@ -115,11 +116,11 @@ func execProcess(context *cli.Context) (int, error) {
 		return -1, err
 	}
 	if status == libcontainer.Stopped {
-		return -1, fmt.Errorf("cannot exec a container that has stopped")
+		return -1, errors.New("cannot exec a container that has stopped")
 	}
 	path := context.String("process")
 	if path == "" && len(context.Args()) == 1 {
-		return -1, fmt.Errorf("process args cannot be empty")
+		return -1, errors.New("process args cannot be empty")
 	}
 	detach := context.Bool("detach")
 	state, err := container.State()

libcontainer/cgroups/utils_test.go

@@ -4,7 +4,7 @@ package cgroups
 
 import (
 	"bytes"
-	"fmt"
+	"errors"
 	"reflect"
 	"strings"
 	"testing"
@@ -372,7 +372,7 @@ func TestParseCgroupString(t *testing.T) {
 		},
 		{
 			input:         `malformed input`,
-			expectedError: fmt.Errorf(`invalid cgroup entry: must contain at least two colons: malformed input`),
+			expectedError: errors.New(`invalid cgroup entry: must contain at least two colons: malformed input`),
 		},
 	}
 

libcontainer/cgroups/v1_utils.go

@@ -154,7 +154,7 @@ func findCgroupMountpointAndRootFromMI(mounts []*mountinfo.Info, cgroupPath, sub
 
 func (m Mount) GetOwnCgroup(cgroups map[string]string) (string, error) {
 	if len(m.Subsystems) == 0 {
-		return "", fmt.Errorf("no subsystem for mount")
+		return "", errors.New("no subsystem for mount")
 	}
 
 	return getControllerPath(m.Subsystems[0], cgroups)

libcontainer/configs/config_linux.go

@@ -1,17 +1,24 @@
 package configs
 
-import "fmt"
+import "errors"
+
+var (
+	errNoUIDMap   = errors.New("User namespaces enabled, but no uid mappings found.")
+	errNoUserMap  = errors.New("User namespaces enabled, but no user mapping found.")
+	errNoGIDMap   = errors.New("User namespaces enabled, but no gid mappings found.")
+	errNoGroupMap = errors.New("User namespaces enabled, but no group mapping found.")
+)
 
 // HostUID gets the translated uid for the process on host which could be
 // different when user namespaces are enabled.
 func (c Config) HostUID(containerId int) (int, error) {
 	if c.Namespaces.Contains(NEWUSER) {
 		if c.UidMappings == nil {
-			return -1, fmt.Errorf("User namespaces enabled, but no uid mappings found.")
+			return -1, errNoUIDMap
 		}
 		id, found := c.hostIDFromMapping(containerId, c.UidMappings)
 		if !found {
-			return -1, fmt.Errorf("User namespaces enabled, but no user mapping found.")
+			return -1, errNoUserMap
 		}
 		return id, nil
 	}
@@ -30,11 +37,11 @@ func (c Config) HostRootUID() (int, error) {
 func (c Config) HostGID(containerId int) (int, error) {
 	if c.Namespaces.Contains(NEWUSER) {
 		if c.GidMappings == nil {
-			return -1, fmt.Errorf("User namespaces enabled, but no gid mappings found.")
+			return -1, errNoGIDMap
 		}
 		id, found := c.hostIDFromMapping(containerId, c.GidMappings)
 		if !found {
-			return -1, fmt.Errorf("User namespaces enabled, but no group mapping found.")
+			return -1, errNoGroupMap
 		}
 		return id, nil
 	}

libcontainer/container_linux.go

@@ -666,7 +666,7 @@ func (c *linuxContainer) Resume() error {
 		return err
 	}
 	if status != Paused {
-		return newGenericError(fmt.Errorf("container not paused"), ContainerNotPaused)
+		return newGenericError(errors.New("container not paused"), ContainerNotPaused)
 	}
 	if err := c.cgroupManager.Freeze(configs.Thawed); err != nil {
 		return err

libcontainer/factory_linux.go

@@ -31,7 +31,10 @@ const (
 	execFifoFilename = "exec.fifo"
 )
 
-var idRegex = regexp.MustCompile(`^[\w+-\.]+$`)
+var (
+	idRegex      = regexp.MustCompile(`^[\w+-\.]+$`)
+	errNoSystemd = errors.New("systemd not running on this host, can't use systemd as cgroups manager")
+)
 
 // InitArgs returns an options func to configure a LinuxFactory with the
 // provided init binary path and arguments.
@@ -80,7 +83,7 @@ func systemdCgroupV2(l *LinuxFactory, rootless bool) error {
 // containers that use systemd to create and manage cgroups.
 func SystemdCgroups(l *LinuxFactory) error {
 	if !systemd.IsRunningSystemd() {
-		return fmt.Errorf("systemd not running on this host, can't use systemd as cgroups manager")
+		return errNoSystemd
 	}
 
 	if cgroups.IsCgroup2UnifiedMode() {
@@ -97,11 +100,11 @@ func SystemdCgroups(l *LinuxFactory) error {
 // RootlessSystemdCgroups is rootless version of SystemdCgroups.
 func RootlessSystemdCgroups(l *LinuxFactory) error {
 	if !systemd.IsRunningSystemd() {
-		return fmt.Errorf("systemd not running on this host, can't use systemd as cgroups manager")
+		return errNoSystemd
 	}
 
 	if !cgroups.IsCgroup2UnifiedMode() {
-		return fmt.Errorf("cgroup v2 not enabled on this host, can't use systemd (rootless) as cgroups manager")
+		return errors.New("cgroup v2 not enabled on this host, can't use systemd (rootless) as cgroups manager")
 	}
 	return systemdCgroupV2(l, true)
 }
@@ -246,7 +249,7 @@ type LinuxFactory struct {
 
 func (l *LinuxFactory) Create(id string, config *configs.Config) (Container, error) {
 	if l.Root == "" {
-		return nil, newGenericError(fmt.Errorf("invalid root"), ConfigInvalid)
+		return nil, newGenericError(errors.New("invalid root"), ConfigInvalid)
 	}
 	if err := l.validateID(id); err != nil {
 		return nil, err
@@ -289,7 +292,7 @@ func (l *LinuxFactory) Create(id string, config *configs.Config) (Container, err
 
 func (l *LinuxFactory) Load(id string) (Container, error) {
 	if l.Root == "" {
-		return nil, newGenericError(fmt.Errorf("invalid root"), ConfigInvalid)
+		return nil, newGenericError(errors.New("invalid root"), ConfigInvalid)
 	}
 	// when load, we need to check id is valid or not.
 	if err := l.validateID(id); err != nil {

libcontainer/generic_error_test.go

@@ -1,20 +1,20 @@
 package libcontainer
 
 import (
-	"fmt"
+	"errors"
 	"io/ioutil"
 	"testing"
 )
 
 func TestErrorDetail(t *testing.T) {
-	err := newGenericError(fmt.Errorf("test error"), SystemError)
+	err := newGenericError(errors.New("test error"), SystemError)
 	if derr := err.Detail(ioutil.Discard); derr != nil {
 		t.Fatal(derr)
 	}
 }
 
 func TestErrorWithCode(t *testing.T) {
-	err := newGenericError(fmt.Errorf("test error"), SystemError)
+	err := newGenericError(errors.New("test error"), SystemError)
 	if code := err.Code(); code != SystemError {
 		t.Fatalf("expected err code %q but %q", SystemError, code)
 	}
@@ -35,7 +35,7 @@ func TestErrorWithError(t *testing.T) {
 	}
 
 	for _, v := range cc {
-		err := newSystemErrorWithCause(fmt.Errorf(v.errmsg), v.cause)
+		err := newSystemErrorWithCause(errors.New(v.errmsg), v.cause)
 
 		msg := err.Error()
 		if v.cause == "" && msg != v.errmsg {

libcontainer/process.go

@@ -1,7 +1,7 @@
 package libcontainer
 
 import (
-	"fmt"
+	"errors"
 	"io"
 	"math"
 	"os"
@@ -9,6 +9,8 @@ import (
 	"github.com/opencontainers/runc/libcontainer/configs"
 )
 
+var errInvalidProcess = errors.New("invalid process")
+
 type processOperations interface {
 	wait() (*os.ProcessState, error)
 	signal(sig os.Signal) error
@@ -84,7 +86,7 @@ type Process struct {
 // Wait releases any resources associated with the Process
 func (p Process) Wait() (*os.ProcessState, error) {
 	if p.ops == nil {
-		return nil, newGenericError(fmt.Errorf("invalid process"), NoProcessOps)
+		return nil, newGenericError(errInvalidProcess, NoProcessOps)
 	}
 	return p.ops.wait()
 }
@@ -94,7 +96,7 @@ func (p Process) Pid() (int, error) {
 	// math.MinInt32 is returned here, because it's invalid value
 	// for the kill() system call.
 	if p.ops == nil {
-		return math.MinInt32, newGenericError(fmt.Errorf("invalid process"), NoProcessOps)
+		return math.MinInt32, newGenericError(errInvalidProcess, NoProcessOps)
 	}
 	return p.ops.pid(), nil
 }
@@ -102,7 +104,7 @@ func (p Process) Pid() (int, error) {
 // Signal sends a signal to the Process.
 func (p Process) Signal(sig os.Signal) error {
 	if p.ops == nil {
-		return newGenericError(fmt.Errorf("invalid process"), NoProcessOps)
+		return newGenericError(errInvalidProcess, NoProcessOps)
 	}
 	return p.ops.signal(sig)
 }

libcontainer/restored_process.go

@@ -3,7 +3,7 @@
 package libcontainer
 
 import (
-	"fmt"
+	"errors"
 	"os"
 	"os/exec"
 
@@ -31,7 +31,7 @@ type restoredProcess struct {
 }
 
 func (p *restoredProcess) start() error {
-	return newGenericError(fmt.Errorf("restored process cannot be started"), SystemError)
+	return newGenericError(errors.New("restored process cannot be started"), SystemError)
 }
 
 func (p *restoredProcess) pid() int {
@@ -89,7 +89,7 @@ type nonChildProcess struct {
 }
 
 func (p *nonChildProcess) start() error {
-	return newGenericError(fmt.Errorf("restored process cannot be started"), SystemError)
+	return newGenericError(errors.New("restored process cannot be started"), SystemError)
 }
 
 func (p *nonChildProcess) pid() int {
@@ -97,11 +97,11 @@ func (p *nonChildProcess) pid() int {
 }
 
 func (p *nonChildProcess) terminate() error {
-	return newGenericError(fmt.Errorf("restored process cannot be terminated"), SystemError)
+	return newGenericError(errors.New("restored process cannot be terminated"), SystemError)
 }
 
 func (p *nonChildProcess) wait() (*os.ProcessState, error) {
-	return nil, newGenericError(fmt.Errorf("restored process cannot be waited on"), SystemError)
+	return nil, newGenericError(errors.New("restored process cannot be waited on"), SystemError)
 }
 
 func (p *nonChildProcess) startTime() (uint64, error) {

libcontainer/specconv/spec_linux.go

@@ -216,7 +216,7 @@ func CreateLibcontainerConfig(opts *CreateOpts) (*configs.Config, error) {
 	}
 	spec := opts.Spec
 	if spec.Root == nil {
-		return nil, fmt.Errorf("Root must be specified")
+		return nil, errors.New("Root must be specified")
 	}
 	rootfsPath := spec.Root.Path
 	if !filepath.IsAbs(rootfsPath) {
@@ -263,7 +263,7 @@ func CreateLibcontainerConfig(opts *CreateOpts) (*configs.Config, error) {
 			return nil, fmt.Errorf("rootfsPropagation=%v is not supported", spec.Linux.RootfsPropagation)
 		}
 		if config.NoPivotRoot && (config.RootPropagation&unix.MS_PRIVATE != 0) {
-			return nil, fmt.Errorf("rootfsPropagation of [r]private is not safe without pivot_root")
+			return nil, errors.New("rootfsPropagation of [r]private is not safe without pivot_root")
 		}
 
 		for _, ns := range spec.Linux.Namespaces {
@@ -858,7 +858,7 @@ func SetupSeccomp(config *specs.LinuxSeccomp) (*configs.Seccomp, error) {
 
 	// We don't currently support seccomp flags.
 	if len(config.Flags) != 0 {
-		return nil, fmt.Errorf("seccomp flags are not yet supported by runc")
+		return nil, errors.New("seccomp flags are not yet supported by runc")
 	}
 
 	newConfig := new(configs.Seccomp)

libcontainer/state_linux.go

@@ -3,6 +3,7 @@
 package libcontainer
 
 import (
+	"errors"
 	"fmt"
 	"os"
 	"path/filepath"
@@ -117,7 +118,7 @@ func (r *runningState) transition(s containerState) error {
 	switch s.(type) {
 	case *stoppedState:
 		if r.c.runType() == Running {
-			return newGenericError(fmt.Errorf("container still running"), ContainerNotStopped)
+			return newGenericError(errors.New("container still running"), ContainerNotStopped)
 		}
 		r.c.state = s
 		return nil
@@ -132,7 +133,7 @@ func (r *runningState) transition(s containerState) error {
 
 func (r *runningState) destroy() error {
 	if r.c.runType() == Running {
-		return newGenericError(fmt.Errorf("container is not destroyed"), ContainerNotStopped)
+		return newGenericError(errors.New("container is not destroyed"), ContainerNotStopped)
 	}
 	return destroy(r.c)
 }
@@ -190,7 +191,7 @@ func (p *pausedState) destroy() error {
 		}
 		return destroy(p.c)
 	}
-	return newGenericError(fmt.Errorf("container is paused"), ContainerPaused)
+	return newGenericError(errors.New("container is paused"), ContainerPaused)
 }
 
 // restoredState is the same as the running state but also has associated checkpoint

libcontainer/user/user.go

@@ -119,7 +119,7 @@ func ParsePasswdFileFilter(path string, filter func(User) bool) ([]User, error)
 
 func ParsePasswdFilter(r io.Reader, filter func(User) bool) ([]User, error) {
 	if r == nil {
-		return nil, fmt.Errorf("nil source for passwd-formatted data")
+		return nil, errors.New("nil source for passwd-formatted data")
 	}
 
 	var (
@@ -177,7 +177,7 @@ func ParseGroupFileFilter(path string, filter func(Group) bool) ([]Group, error)
 
 func ParseGroupFilter(r io.Reader, filter func(Group) bool) ([]Group, error) {
 	if r == nil {
-		return nil, fmt.Errorf("nil source for group-formatted data")
+		return nil, errors.New("nil source for group-formatted data")
 	}
 
 	var (
@@ -487,7 +487,7 @@ func ParseSubIDFileFilter(path string, filter func(SubID) bool) ([]SubID, error)
 
 func ParseSubIDFilter(r io.Reader, filter func(SubID) bool) ([]SubID, error) {
 	if r == nil {
-		return nil, fmt.Errorf("nil source for subid-formatted data")
+		return nil, errors.New("nil source for subid-formatted data")
 	}
 
 	var (
@@ -540,7 +540,7 @@ func ParseIDMapFileFilter(path string, filter func(IDMap) bool) ([]IDMap, error)
 
 func ParseIDMapFilter(r io.Reader, filter func(IDMap) bool) ([]IDMap, error) {
 	if r == nil {
-		return nil, fmt.Errorf("nil source for idmap-formatted data")
+		return nil, errors.New("nil source for idmap-formatted data")
 	}
 
 	var (