blob: fee6a7c8f46611cff513f233f59f9c0b85dd21ef [file] [log] [blame]
khenaidoo59ce9dd2019-11-11 13:05:32 -05001// Copyright 2015 The etcd Authors
2//
3// Licensed under the Apache License, Version 2.0 (the "License");
4// you may not use this file except in compliance with the License.
5// You may obtain a copy of the License at
6//
7// http://www.apache.org/licenses/LICENSE-2.0
8//
9// Unless required by applicable law or agreed to in writing, software
10// distributed under the License is distributed on an "AS IS" BASIS,
11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12// See the License for the specific language governing permissions and
13// limitations under the License.
14
15package fileutil
16
17import (
18 "os"
19 "syscall"
20 "time"
21)
22
23func TryLockFile(path string, flag int, perm os.FileMode) (*LockedFile, error) {
24 if err := os.Chmod(path, syscall.DMEXCL|PrivateFileMode); err != nil {
25 return nil, err
26 }
27 f, err := os.Open(path, flag, perm)
28 if err != nil {
29 return nil, ErrLocked
30 }
31 return &LockedFile{f}, nil
32}
33
34func LockFile(path string, flag int, perm os.FileMode) (*LockedFile, error) {
35 if err := os.Chmod(path, syscall.DMEXCL|PrivateFileMode); err != nil {
36 return nil, err
37 }
38 for {
39 f, err := os.OpenFile(path, flag, perm)
40 if err == nil {
41 return &LockedFile{f}, nil
42 }
43 time.Sleep(10 * time.Millisecond)
44 }
45}