tailscale/atomicfile/atomicfile.go
Will Norris 71029cea2d all: update copyright and license headers
This updates all source files to use a new standard header for copyright
and license declaration.  Notably, copyright no longer includes a date,
and we now use the standard SPDX-License-Identifier header.

This commit was done almost entirely mechanically with perl, and then
some minimal manual fixes.

Updates #6865

Signed-off-by: Will Norris <will@tailscale.com>
2023-01-27 15:36:29 -08:00

46 lines
1.0 KiB
Go

// Copyright (c) Tailscale Inc & AUTHORS
// SPDX-License-Identifier: BSD-3-Clause
// Package atomicfile contains code related to writing to filesystems
// atomically.
//
// This package should be considered internal; its API is not stable.
package atomicfile // import "tailscale.com/atomicfile"
import (
"os"
"path/filepath"
"runtime"
)
// WriteFile writes data to filename+some suffix, then renames it
// into filename. The perm argument is ignored on Windows.
func WriteFile(filename string, data []byte, perm os.FileMode) (err error) {
f, err := os.CreateTemp(filepath.Dir(filename), filepath.Base(filename)+".tmp")
if err != nil {
return err
}
tmpName := f.Name()
defer func() {
if err != nil {
f.Close()
os.Remove(tmpName)
}
}()
if _, err := f.Write(data); err != nil {
return err
}
if runtime.GOOS != "windows" {
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)
}