[VOL-4291] Rw-core updates for gRPC migration

Change-Id: I8d5a554409115b29318089671ca4e1ab3fa98810
diff --git a/vendor/github.com/coreos/etcd/pkg/fileutil/fileutil.go b/vendor/github.com/coreos/etcd/pkg/fileutil/fileutil.go
new file mode 100644
index 0000000..3c73916
--- /dev/null
+++ b/vendor/github.com/coreos/etcd/pkg/fileutil/fileutil.go
@@ -0,0 +1,147 @@
+// Copyright 2015 The etcd 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 fileutil implements utility functions related to files and paths.
+package fileutil
+
+import (
+	"fmt"
+	"io"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"sort"
+
+	"github.com/coreos/pkg/capnslog"
+)
+
+const (
+	// PrivateFileMode grants owner to read/write a file.
+	PrivateFileMode = 0600
+)
+
+var (
+	plog = capnslog.NewPackageLogger("github.com/coreos/etcd", "pkg/fileutil")
+)
+
+// IsDirWriteable checks if dir is writable by writing and removing a file
+// to dir. It returns nil if dir is writable.
+func IsDirWriteable(dir string) error {
+	f := filepath.Join(dir, ".touch")
+	if err := ioutil.WriteFile(f, []byte(""), PrivateFileMode); err != nil {
+		return err
+	}
+	return os.Remove(f)
+}
+
+// ReadDir returns the filenames in the given directory in sorted order.
+func ReadDir(dirpath string) ([]string, error) {
+	dir, err := os.Open(dirpath)
+	if err != nil {
+		return nil, err
+	}
+	defer dir.Close()
+	names, err := dir.Readdirnames(-1)
+	if err != nil {
+		return nil, err
+	}
+	sort.Strings(names)
+	return names, nil
+}
+
+// TouchDirAll is similar to os.MkdirAll. It creates directories with 0700 permission if any directory
+// does not exists. TouchDirAll also ensures the given directory is writable.
+func TouchDirAll(dir string) error {
+	// If path is already a directory, MkdirAll does nothing and returns nil, so,
+	// first check if dir exist with an expected permission mode.
+	if Exist(dir) {
+		err := CheckDirPermission(dir, PrivateDirMode)
+		if err != nil {
+			plog.Warningf("check file permission: %v", err)
+		}
+	} else {
+		err := os.MkdirAll(dir, PrivateDirMode)
+		if err != nil {
+			// if mkdirAll("a/text") and "text" is not
+			// a directory, this will return syscall.ENOTDIR
+			return err
+		}
+	}
+
+	return IsDirWriteable(dir)
+}
+
+// CreateDirAll is similar to TouchDirAll but returns error
+// if the deepest directory was not empty.
+func CreateDirAll(dir string) error {
+	err := TouchDirAll(dir)
+	if err == nil {
+		var ns []string
+		ns, err = ReadDir(dir)
+		if err != nil {
+			return err
+		}
+		if len(ns) != 0 {
+			err = fmt.Errorf("expected %q to be empty, got %q", dir, ns)
+		}
+	}
+	return err
+}
+
+func Exist(name string) bool {
+	_, err := os.Stat(name)
+	return err == nil
+}
+
+// ZeroToEnd zeros a file starting from SEEK_CUR to its SEEK_END. May temporarily
+// shorten the length of the file.
+func ZeroToEnd(f *os.File) error {
+	// TODO: support FALLOC_FL_ZERO_RANGE
+	off, err := f.Seek(0, io.SeekCurrent)
+	if err != nil {
+		return err
+	}
+	lenf, lerr := f.Seek(0, io.SeekEnd)
+	if lerr != nil {
+		return lerr
+	}
+	if err = f.Truncate(off); err != nil {
+		return err
+	}
+	// make sure blocks remain allocated
+	if err = Preallocate(f, lenf, true); err != nil {
+		return err
+	}
+	_, err = f.Seek(off, io.SeekStart)
+	return err
+}
+
+// CheckDirPermission checks permission on an existing dir.
+// Returns error if dir is empty or exist with a different permission than specified.
+func CheckDirPermission(dir string, perm os.FileMode) error {
+	if !Exist(dir) {
+		return fmt.Errorf("directory %q empty, cannot check permission.", dir)
+	}
+	//check the existing permission on the directory
+	dirInfo, err := os.Stat(dir)
+	if err != nil {
+		return err
+	}
+	dirMode := dirInfo.Mode().Perm()
+	if dirMode != perm {
+		err = fmt.Errorf("directory %q exist, but the permission is %q. The recommended permission is %q to prevent possible unprivileged access to the data.", dir, dirInfo.Mode(), os.FileMode(PrivateDirMode))
+		return err
+	}
+	return nil
+}