55 lines
1.2 KiB
Go
55 lines
1.2 KiB
Go
// Copyright 2016 The Prometheus 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.
|
|
|
|
// +build darwin dragonfly freebsd linux netbsd openbsd
|
|
|
|
package fileutil
|
|
|
|
import (
|
|
"os"
|
|
"syscall"
|
|
)
|
|
|
|
type unixLock struct {
|
|
f *os.File
|
|
}
|
|
|
|
func (l *unixLock) Release() error {
|
|
if err := l.set(false); err != nil {
|
|
return err
|
|
}
|
|
return l.f.Close()
|
|
}
|
|
|
|
func (l *unixLock) set(lock bool) error {
|
|
how := syscall.LOCK_UN
|
|
if lock {
|
|
how = syscall.LOCK_EX
|
|
}
|
|
return syscall.Flock(int(l.f.Fd()), how|syscall.LOCK_NB)
|
|
}
|
|
|
|
func newLock(fileName string) (Releaser, error) {
|
|
f, err := os.OpenFile(fileName, os.O_RDWR|os.O_CREATE, 0666)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
l := &unixLock{f}
|
|
err = l.set(true)
|
|
if err != nil {
|
|
f.Close()
|
|
return nil, err
|
|
}
|
|
return l, nil
|
|
}
|