atomicfile: use ioutil.TempFile, sync
package atomicfile // import "tailscale.com/atomicfile"
import (
- "fmt"
"io/ioutil"
"os"
+ "path/filepath"
)
// WriteFile writes data to filename+some suffix, then renames it
// into filename.
-func WriteFile(filename string, data []byte, perm os.FileMode) error {
- tmpname := filename + ".new.tmp"
- if err := ioutil.WriteFile(tmpname, data, perm); err != nil {
- return fmt.Errorf("%#v: %v", tmpname, err)
+func WriteFile(filename string, data []byte, perm os.FileMode) (err error) {
+ f, err := ioutil.TempFile(filepath.Dir(filename), filepath.Base(filename)+".tmp")
+ if err != nil {
+ return err
}
- if err := os.Rename(tmpname, filename); err != nil {
- return fmt.Errorf("%#v->%#v: %v", tmpname, filename, err)
+ tmpName := f.Name()
+ defer func() {
+ if err != nil {
+ f.Close()
+ os.Remove(tmpName)
}
- return nil
+ }()
+ if _, err := f.Write(data); err != nil {
+ return err
+ }
+ if err := f.Chmod(perm); err != nil {
+ return err
+ }
+ if err := f.Sync(); err != nil {
+ return err
+ }
+ if err := f.Close(); err != nil {
+ return err
+ }
+ return os.Rename(tmpName, filename)
}
