Move HostUtil to pkg/volume/util/hostutil

This patch moves the HostUtil functionality from the util/mount package
to the volume/util/hostutil package.

All `*NewHostUtil*` calls are changed to return concrete types instead
of interfaces.

All callers are changed to use the `*NewHostUtil*` methods instead of
directly instantiating the concrete types.

pkg/volume/util/hostutil/hostutil.go

@@ -0,0 +1,109 @@
+/*
+Copyright 2014 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 hostutil
+
+import (
+	"fmt"
+	"os"
+
+	"k8s.io/kubernetes/pkg/util/mount"
+)
+
+// FileType enumerates the known set of possible file types.
+type FileType string
+
+const (
+	// FileTypeBlockDev defines a constant for the block device FileType.
+	FileTypeBlockDev FileType = "BlockDevice"
+	// FileTypeCharDev defines a constant for the character device FileType.
+	FileTypeCharDev FileType = "CharDevice"
+	// FileTypeDirectory defines a constant for the directory FileType.
+	FileTypeDirectory FileType = "Directory"
+	// FileTypeFile defines a constant for the file FileType.
+	FileTypeFile FileType = "File"
+	// FileTypeSocket defines a constant for the socket FileType.
+	FileTypeSocket FileType = "Socket"
+	// FileTypeUnknown defines a constant for an unknown FileType.
+	FileTypeUnknown FileType = ""
+)
+
+// HostUtils defines the set of methods for interacting with paths on a host.
+type HostUtils interface {
+	// DeviceOpened determines if the device (e.g. /dev/sdc) is in use elsewhere
+	// on the system, i.e. still mounted.
+	DeviceOpened(pathname string) (bool, error)
+	// PathIsDevice determines if a path is a device.
+	PathIsDevice(pathname string) (bool, error)
+	// GetDeviceNameFromMount finds the device name by checking the mount path
+	// to get the global mount path within its plugin directory.
+	GetDeviceNameFromMount(mounter mount.Interface, mountPath, pluginMountDir string) (string, error)
+	// MakeRShared checks that given path is on a mount with 'rshared' mount
+	// propagation. If not, it bind-mounts the path as rshared.
+	MakeRShared(path string) error
+	// GetFileType checks for file/directory/socket/block/character devices.
+	GetFileType(pathname string) (FileType, error)
+	// PathExists tests if the given path already exists
+	// Error is returned on any other error than "file not found".
+	PathExists(pathname string) (bool, error)
+	// EvalHostSymlinks returns the path name after evaluating symlinks.
+	EvalHostSymlinks(pathname string) (string, error)
+	// GetOwner returns the integer ID for the user and group of the given path
+	GetOwner(pathname string) (int64, int64, error)
+	// GetSELinuxSupport returns true if given path is on a mount that supports
+	// SELinux.
+	GetSELinuxSupport(pathname string) (bool, error)
+	// GetMode returns permissions of the path.
+	GetMode(pathname string) (os.FileMode, error)
+}
+
+// Compile-time check to ensure all HostUtil implementations satisfy
+// the Interface.
+var _ HostUtils = &HostUtil{}
+
+// getFileType checks for file/directory/socket and block/character devices.
+func getFileType(pathname string) (FileType, error) {
+	var pathType FileType
+	info, err := os.Stat(pathname)
+	if os.IsNotExist(err) {
+		return pathType, fmt.Errorf("path %q does not exist", pathname)
+	}
+	// err in call to os.Stat
+	if err != nil {
+		return pathType, err
+	}
+
+	// checks whether the mode is the target mode.
+	isSpecificMode := func(mode, targetMode os.FileMode) bool {
+		return mode&targetMode == targetMode
+	}
+
+	mode := info.Mode()
+	if mode.IsDir() {
+		return FileTypeDirectory, nil
+	} else if mode.IsRegular() {
+		return FileTypeFile, nil
+	} else if isSpecificMode(mode, os.ModeSocket) {
+		return FileTypeSocket, nil
+	} else if isSpecificMode(mode, os.ModeDevice) {
+		if isSpecificMode(mode, os.ModeCharDevice) {
+			return FileTypeCharDev, nil
+		}
+		return FileTypeBlockDev, nil
+	}
+
+	return pathType, fmt.Errorf("only recognise file, directory, socket, block device and character device")
+}