k3s/vendor/go.etcd.io/etcd/pkg/fileutil/lock_plan9.go

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2020-05-07 05:09:19 +00:00
// 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 (
"os"
"syscall"
"time"
)
func TryLockFile(path string, flag int, perm os.FileMode) (*LockedFile, error) {
if err := os.Chmod(path, syscall.DMEXCL|PrivateFileMode); err != nil {
return nil, err
}
f, err := os.Open(path, flag, perm)
if err != nil {
return nil, ErrLocked
}
return &LockedFile{f}, nil
}
func LockFile(path string, flag int, perm os.FileMode) (*LockedFile, error) {
if err := os.Chmod(path, syscall.DMEXCL|PrivateFileMode); err != nil {
return nil, err
}
for {
f, err := os.OpenFile(path, flag, perm)
if err == nil {
return &LockedFile{f}, nil
}
time.Sleep(10 * time.Millisecond)
}
}