Add ExecMounter

pkg/util/mount/BUILD

@@ -17,6 +17,7 @@ go_library(
         "nsenter_mount_unsupported.go",
     ] + select({
         "@io_bazel_rules_go//go/platform:linux_amd64": [
+            "exec_mount.go",
             "mount_linux.go",
             "nsenter_mount.go",
         ],
@@ -46,6 +47,7 @@ go_test(
         "safe_format_and_mount_test.go",
     ] + select({
         "@io_bazel_rules_go//go/platform:linux_amd64": [
+            "exec_mount_test.go",
             "mount_linux_test.go",
             "nsenter_mount_test.go",
         ],

pkg/util/mount/exec_mount.go

+// +build linux
+
+/*
+Copyright 2017 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package mount
+
+import (
+	"fmt"
+
+	"github.com/golang/glog"
+)
+
+// ExecMounter is a mounter that uses provided Exec interface to mount and
+// unmount a filesystem. For all other calls it uses a wrapped mounter.
+type execMounter struct {
+	wrappedMounter Interface
+	exec           Exec
+}
+
+func NewExecMounter(exec Exec, wrapped Interface) Interface {
+	return &execMounter{
+		wrappedMounter: wrapped,
+		exec:           exec,
+	}
+}
+
+// execMounter implements mount.Interface
+var _ Interface = &execMounter{}
+
+// Mount runs mount(8) using given exec interface.
+func (m *execMounter) Mount(source string, target string, fstype string, options []string) error {
+	bind, bindRemountOpts := isBind(options)
+
+	if bind {
+		err := m.doExecMount(source, target, fstype, []string{"bind"})
+		if err != nil {
+			return err
+		}
+		return m.doExecMount(source, target, fstype, bindRemountOpts)
+	}
+
+	return m.doExecMount(source, target, fstype, options)
+}
+
+// doExecMount calls exec(mount <waht> <where>) using given exec interface.
+func (m *execMounter) doExecMount(source, target, fstype string, options []string) error {
+	glog.V(5).Infof("Exec Mounting %s %s %s %v", source, target, fstype, options)
+	mountArgs := makeMountArgs(source, target, fstype, options)
+	output, err := m.exec.Run("mount", mountArgs...)
+	glog.V(5).Infof("Exec mounted %v: %v: %s", mountArgs, err, string(output))
+	if err != nil {
+		return fmt.Errorf("mount failed: %v\nMounting command: %s\nMounting arguments: %s %s %s %v\nOutput: %s\n",
+			err, "mount", source, target, fstype, options, string(output))
+	}
+
+	return err
+}
+
+// Unmount runs umount(8) using given exec interface.
+func (m *execMounter) Unmount(target string) error {
+	outputBytes, err := m.exec.Run("umount", target)
+	if err == nil {
+		glog.V(5).Infof("Exec unmounted %s: %s", target, string(outputBytes))
+	} else {
+		glog.V(5).Infof("Failed to exec unmount %s: err: %q, umount output: %s", target, err, string(outputBytes))
+	}
+
+	return err
+}
+
+// List returns a list of all mounted filesystems.
+func (m *execMounter) List() ([]MountPoint, error) {
+	return m.wrappedMounter.List()
+}
+
+// IsLikelyNotMountPoint determines whether a path is a mountpoint.
+func (m *execMounter) IsLikelyNotMountPoint(file string) (bool, error) {
+	return m.wrappedMounter.IsLikelyNotMountPoint(file)
+}
+
+// DeviceOpened checks if block device in use by calling Open with O_EXCL flag.
+// Returns true if open returns errno EBUSY, and false if errno is nil.
+// Returns an error if errno is any error other than EBUSY.
+// Returns with error if pathname is not a device.
+func (m *execMounter) DeviceOpened(pathname string) (bool, error) {
+	return m.wrappedMounter.DeviceOpened(pathname)
+}
+
+// PathIsDevice uses FileInfo returned from os.Stat to check if path refers
+// to a device.
+func (m *execMounter) PathIsDevice(pathname string) (bool, error) {
+	return m.wrappedMounter.PathIsDevice(pathname)
+}
+
+//GetDeviceNameFromMount given a mount point, find the volume id from checking /proc/mounts
+func (m *execMounter) GetDeviceNameFromMount(mountPath, pluginDir string) (string, error) {
+	return m.wrappedMounter.GetDeviceNameFromMount(mountPath, pluginDir)
+}
+
+func (m *execMounter) IsMountPointMatch(mp MountPoint, dir string) bool {
+	return m.wrappedMounter.IsMountPointMatch(mp, dir)
+}
+
+func (m *execMounter) IsNotMountPoint(dir string) (bool, error) {
+	return m.wrappedMounter.IsNotMountPoint(dir)
+}
+
+func (m *execMounter) MakeRShared(path string) error {
+	return m.wrappedMounter.MakeRShared(path)
+}
+
+func (m *execMounter) GetFileType(pathname string) (FileType, error) {
+	return m.wrappedMounter.GetFileType(pathname)
+}
+
+func (m *execMounter) MakeFile(pathname string) error {
+	return m.wrappedMounter.MakeFile(pathname)
+}
+
+func (m *execMounter) MakeDir(pathname string) error {
+	return m.wrappedMounter.MakeDir(pathname)
+}
+
+func (m *execMounter) ExistsPath(pathname string) bool {
+	return m.wrappedMounter.ExistsPath(pathname)
+}

pkg/util/mount/exec_mount_test.go

+// +build linux
+
+/*
+Copyright 2017 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package mount
+
+import (
+	"fmt"
+	"reflect"
+	"strings"
+	"testing"
+)
+
+var (
+	sourcePath      = "/mnt/srv"
+	destinationPath = "/mnt/dst"
+	fsType          = "xfs"
+	mountOptions    = []string{"vers=1", "foo=bar"}
+)
+
+func TestMount(t *testing.T) {
+	exec := NewFakeExec(func(cmd string, args ...string) ([]byte, error) {
+		if cmd != "mount" {
+			t.Errorf("expected mount command, got %q", cmd)
+		}
+		// mount -t fstype -o options source target
+		expectedArgs := []string{"-t", fsType, "-o", strings.Join(mountOptions, ","), sourcePath, destinationPath}
+		if !reflect.DeepEqual(expectedArgs, args) {
+			t.Errorf("expected arguments %q, got %q", strings.Join(expectedArgs, " "), strings.Join(args, " "))
+		}
+		return nil, nil
+	})
+
+	wrappedMounter := &fakeMounter{t}
+	mounter := NewExecMounter(exec, wrappedMounter)
+
+	mounter.Mount(sourcePath, destinationPath, fsType, mountOptions)
+}
+
+func TestBindMount(t *testing.T) {
+	cmdCount := 0
+	exec := NewFakeExec(func(cmd string, args ...string) ([]byte, error) {
+		cmdCount++
+		if cmd != "mount" {
+			t.Errorf("expected mount command, got %q", cmd)
+		}
+		var expectedArgs []string
+		switch cmdCount {
+		case 1:
+			// mount -t fstype -o "bind" source target
+			expectedArgs = []string{"-t", fsType, "-o", "bind", sourcePath, destinationPath}
+		case 2:
+			// mount -t fstype -o "remount,opts" source target
+			expectedArgs = []string{"-t", fsType, "-o", "remount," + strings.Join(mountOptions, ","), sourcePath, destinationPath}
+		}
+		if !reflect.DeepEqual(expectedArgs, args) {
+			t.Errorf("expected arguments %q, got %q", strings.Join(expectedArgs, " "), strings.Join(args, " "))
+		}
+		return nil, nil
+	})
+
+	wrappedMounter := &fakeMounter{t}
+	mounter := NewExecMounter(exec, wrappedMounter)
+	bindOptions := append(mountOptions, "bind")
+	mounter.Mount(sourcePath, destinationPath, fsType, bindOptions)
+}
+
+func TestUnmount(t *testing.T) {
+	exec := NewFakeExec(func(cmd string, args ...string) ([]byte, error) {
+		if cmd != "umount" {
+			t.Errorf("expected unmount command, got %q", cmd)
+		}
+		// unmount $target
+		expectedArgs := []string{destinationPath}
+		if !reflect.DeepEqual(expectedArgs, args) {
+			t.Errorf("expected arguments %q, got %q", strings.Join(expectedArgs, " "), strings.Join(args, " "))
+		}
+		return nil, nil
+	})
+
+	wrappedMounter := &fakeMounter{t}
+	mounter := NewExecMounter(exec, wrappedMounter)
+
+	mounter.Unmount(destinationPath)
+}
+
+/* Fake wrapped mounter */
+type fakeMounter struct {
+	t *testing.T
+}
+
+func (fm *fakeMounter) Mount(source string, target string, fstype string, options []string) error {
+	// Mount() of wrapped mounter should never be called. We call exec instead.
+	fm.t.Errorf("Unexpected wrapped mount call")
+	return fmt.Errorf("Unexpected wrapped mount call")
+}
+
+func (fm *fakeMounter) Unmount(target string) error {
+	// umount() of wrapped mounter should never be called. We call exec instead.
+	fm.t.Errorf("Unexpected wrapped mount call")
+	return fmt.Errorf("Unexpected wrapped mount call")
+}
+
+func (fm *fakeMounter) List() ([]MountPoint, error) {
+	return nil, nil
+}
+func (fm *fakeMounter) IsMountPointMatch(mp MountPoint, dir string) bool {
+	return false
+}
+func (fm *fakeMounter) IsNotMountPoint(file string) (bool, error) {
+	return false, nil
+}
+func (fm *fakeMounter) IsLikelyNotMountPoint(file string) (bool, error) {
+	return false, nil
+}
+func (fm *fakeMounter) DeviceOpened(pathname string) (bool, error) {
+	return false, nil
+}
+func (fm *fakeMounter) PathIsDevice(pathname string) (bool, error) {
+	return false, nil
+}
+func (fm *fakeMounter) GetDeviceNameFromMount(mountPath, pluginDir string) (string, error) {
+	return "", nil
+}
+func (fm *fakeMounter) MakeRShared(path string) error {
+	return nil
+}
+func (fm *fakeMounter) MakeFile(pathname string) error {
+	return nil
+}
+func (fm *fakeMounter) MakeDir(pathname string) error {
+	return nil
+}
+func (fm *fakeMounter) ExistsPath(pathname string) bool {
+	return false
+}
+func (fm *fakeMounter) GetFileType(pathname string) (FileType, error) {
+	return FileTypeFile, nil
+}