libct: Mount: rm {Pre,Post}mountCmds

Those were added by commit 59c5c3ac0 back in Apr 2015, but AFAICS were
never used and are obsoleted by more generic container hooks (initially
added by commit 05567f2c94 in Sep 2015).

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

libcontainer/configs/mount.go

@@ -35,12 +35,6 @@ type Mount struct {
 
 	// Extensions are additional flags that are specific to runc.
 	Extensions int `json:"extensions"`
-
-	// Optional Command to be run before Source is mounted.
-	PremountCmds []Command `json:"premount_cmds"`
-
-	// Optional Command to be run after Source is mounted.
-	PostmountCmds []Command `json:"postmount_cmds"`
 }
 
 func (m *Mount) IsBind() bool {

libcontainer/integration/exec_test.go

@@ -840,55 +840,6 @@ func TestPassExtraFiles(t *testing.T) {
 	}
 }
 
-func TestMountCmds(t *testing.T) {
-	if testing.Short() {
-		return
-	}
-
-	tmpDir := t.TempDir()
-	config := newTemplateConfig(t, nil)
-	rootfs := config.Rootfs
-	config.Mounts = append(config.Mounts, &configs.Mount{
-		Source:      tmpDir,
-		Destination: "/tmp",
-		Device:      "bind",
-		Flags:       unix.MS_BIND | unix.MS_REC,
-		PremountCmds: []configs.Command{
-			{Path: "touch", Args: []string{filepath.Join(tmpDir, "hello")}},
-			{Path: "touch", Args: []string{filepath.Join(tmpDir, "world")}},
-		},
-		PostmountCmds: []configs.Command{
-			{Path: "cp", Args: []string{filepath.Join(rootfs, "tmp", "hello"), filepath.Join(rootfs, "tmp", "hello-backup")}},
-			{Path: "cp", Args: []string{filepath.Join(rootfs, "tmp", "world"), filepath.Join(rootfs, "tmp", "world-backup")}},
-		},
-	})
-
-	container, err := newContainer(t, config)
-	ok(t, err)
-	defer destroyContainer(container)
-
-	pconfig := libcontainer.Process{
-		Cwd:  "/",
-		Args: []string{"sh", "-c", "env"},
-		Env:  standardEnvironment,
-		Init: true,
-	}
-	err = container.Run(&pconfig)
-	ok(t, err)
-
-	// Wait for process
-	waitProcess(&pconfig, t)
-
-	entries, err := os.ReadDir(tmpDir)
-	ok(t, err)
-	expected := []string{"hello", "hello-backup", "world", "world-backup"}
-	for i, e := range entries {
-		if e.Name() != expected[i] {
-			t.Errorf("Got(%s), expect %s", e.Name(), expected[i])
-		}
-	}
-}
-
 func TestSysctl(t *testing.T) {
 	if testing.Short() {
 		return

libcontainer/rootfs_linux.go

@@ -5,7 +5,6 @@ import (
 	"fmt"
 	"io"
 	"os"
-	"os/exec"
 	"path"
 	"path/filepath"
 	"strconv"
@@ -70,12 +69,6 @@ func prepareRootfs(pipe io.ReadWriter, iConfig *initConfig, mountFds []int) (err
 	}
 	setupDev := needsSetupDev(config)
 	for i, m := range config.Mounts {
-		for _, precmd := range m.PremountCmds {
-			if err := mountCmd(precmd); err != nil {
-				return fmt.Errorf("error running premount command: %w", err)
-			}
-		}
-
 		// Just before the loop we checked that if not empty, len(mountFds) == len(config.Mounts).
 		// Therefore, we can access mountFds[i] without any concerns.
 		if mountFds != nil && mountFds[i] != -1 {
@@ -85,12 +78,6 @@ func prepareRootfs(pipe io.ReadWriter, iConfig *initConfig, mountFds []int) (err
 		if err := mountToRootfs(m, mountConfig); err != nil {
 			return fmt.Errorf("error mounting %q to rootfs at %q: %w", m.Source, m.Destination, err)
 		}
-
-		for _, postcmd := range m.PostmountCmds {
-			if err := mountCmd(postcmd); err != nil {
-				return fmt.Errorf("error running postmount command: %w", err)
-			}
-		}
 	}
 
 	if setupDev {
@@ -212,16 +199,6 @@ func cleanupTmp(tmpdir string) {
 	_ = os.RemoveAll(tmpdir)
 }
 
-func mountCmd(cmd configs.Command) error {
-	command := exec.Command(cmd.Path, cmd.Args[:]...)
-	command.Env = cmd.Env
-	command.Dir = cmd.Dir
-	if out, err := command.CombinedOutput(); err != nil {
-		return fmt.Errorf("%#v failed: %s: %w", cmd, string(out), err)
-	}
-	return nil
-}
-
 func prepareBindMount(m *configs.Mount, rootfs string, mountFd *int) error {
 	source := m.Source
 	if mountFd != nil {