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// 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
import (
"fmt"
"io"
"io/ioutil"
"os"
"path/filepath"
"go.uber.org/zap"
)
const (
// PrivateFileMode grants owner to read/write a file.
PrivateFileMode = 0600
)
// 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, err := filepath.Abs(filepath.Join(dir, ".touch"))
if err != nil {
return err
}
if err := ioutil.WriteFile(f, []byte(""), PrivateFileMode); err != nil {
return err
}
return os.Remove(f)
}
// 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(lg *zap.Logger, 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 {
lg.Warn("check file permission", zap.Error(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(lg *zap.Logger, dir string) error {
err := TouchDirAll(lg, 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
}
// Exist returns true if a file or directory exists.
func Exist(name string) bool {
_, err := os.Stat(name)
return err == nil
}
// DirEmpty returns true if a directory empty and can access.
func DirEmpty(name string) bool {
ns, err := ReadDir(name)
return len(ns) == 0 && 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
}
// RemoveMatchFile deletes file if matchFunc is true on an existing dir
// Returns error if the dir does not exist or remove file fail
func RemoveMatchFile(lg *zap.Logger, dir string, matchFunc func(fileName string) bool) error {
if lg == nil {
lg = zap.NewNop()
}
if !Exist(dir) {
return fmt.Errorf("directory %s does not exist", dir)
}
fileNames, err := ReadDir(dir)
if err != nil {
return err
}
var removeFailedFiles []string
for _, fileName := range fileNames {
if matchFunc(fileName) {
file := filepath.Join(dir, fileName)
if err = os.Remove(file); err != nil {
removeFailedFiles = append(removeFailedFiles, fileName)
lg.Error("remove file failed",
zap.String("file", file),
zap.Error(err))
continue
}
}
}
if len(removeFailedFiles) != 0 {
return fmt.Errorf("remove file(s) %v error", removeFailedFiles)
}
return nil
}
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