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45 lines
1.0 KiB
Go
45 lines
1.0 KiB
Go
// Copyright (c) 2019 Tailscale Inc & AUTHORS All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// Package atomicfile contains code related to writing to filesystems
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// atomically.
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//
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// This package should be considered internal; its API is not stable.
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package atomicfile // import "tailscale.com/atomicfile"
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import (
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"io/ioutil"
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"os"
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"path/filepath"
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)
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// WriteFile writes data to filename+some suffix, then renames it
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// into filename.
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func WriteFile(filename string, data []byte, perm os.FileMode) (err error) {
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f, err := ioutil.TempFile(filepath.Dir(filename), filepath.Base(filename)+".tmp")
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if err != nil {
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return err
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}
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tmpName := f.Name()
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defer func() {
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if err != nil {
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f.Close()
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os.Remove(tmpName)
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}
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}()
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if _, err := f.Write(data); err != nil {
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return err
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}
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if err := f.Chmod(perm); err != nil {
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return err
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}
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if err := f.Sync(); err != nil {
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return err
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}
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if err := f.Close(); err != nil {
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return err
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}
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return os.Rename(tmpName, filename)
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}
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