mirror of
https://github.com/k3s-io/k3s.git
synced 2024-06-07 19:41:36 +00:00
64 lines
1.6 KiB
Go
64 lines
1.6 KiB
Go
/*
|
|
Copyright The containerd 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 continuity
|
|
|
|
import (
|
|
"bytes"
|
|
"io"
|
|
"io/ioutil"
|
|
"os"
|
|
"path/filepath"
|
|
)
|
|
|
|
// AtomicWriteFile atomically writes data to a file by first writing to a
|
|
// temp file and calling rename.
|
|
func AtomicWriteFile(filename string, data []byte, perm os.FileMode) error {
|
|
buf := bytes.NewBuffer(data)
|
|
return atomicWriteFile(filename, buf, int64(len(data)), perm)
|
|
}
|
|
|
|
// atomicWriteFile writes data to a file by first writing to a temp
|
|
// file and calling rename.
|
|
func atomicWriteFile(filename string, r io.Reader, dataSize int64, perm os.FileMode) error {
|
|
f, err := ioutil.TempFile(filepath.Dir(filename), ".tmp-"+filepath.Base(filename))
|
|
if err != nil {
|
|
return err
|
|
}
|
|
err = os.Chmod(f.Name(), perm)
|
|
if err != nil {
|
|
f.Close()
|
|
return err
|
|
}
|
|
n, err := io.Copy(f, r)
|
|
if err == nil && n < dataSize {
|
|
f.Close()
|
|
return io.ErrShortWrite
|
|
}
|
|
if err != nil {
|
|
f.Close()
|
|
return err
|
|
}
|
|
if err := f.Sync(); err != nil {
|
|
f.Close()
|
|
return err
|
|
}
|
|
if err := f.Close(); err != nil {
|
|
return err
|
|
}
|
|
return os.Rename(f.Name(), filename)
|
|
}
|