1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
|
// Copyright (c) Tailscale Inc & contributors
// SPDX-License-Identifier: BSD-3-Clause
package paths
import (
"os"
"path/filepath"
"tailscale.com/types/logger"
)
// TryConfigFileMigration carefully copies the contents of oldFile to
// newFile, returning the path which should be used to read the config.
// - if newFile already exists, don't modify it just return its path
// - if neither oldFile nor newFile exist, return newFile for a fresh
// default config to be written to.
// - if oldFile exists but copying to newFile fails, return oldFile so
// there will at least be some config to work with.
func TryConfigFileMigration(logf logger.Logf, oldFile, newFile string) string {
_, err := os.Stat(newFile)
if err == nil {
// Common case for a system which has already been migrated.
return newFile
}
if !os.IsNotExist(err) {
logf("TryConfigFileMigration failed; new file: %v", err)
return newFile
}
contents, err := os.ReadFile(oldFile)
if err != nil {
// Common case for a new user.
return newFile
}
if err = MkStateDir(filepath.Dir(newFile)); err != nil {
logf("TryConfigFileMigration failed; MkStateDir: %v", err)
return oldFile
}
err = os.WriteFile(newFile, contents, 0600)
if err != nil {
removeErr := os.Remove(newFile)
if removeErr != nil {
logf("TryConfigFileMigration failed; write newFile no cleanup: %v, remove err: %v",
err, removeErr)
return oldFile
}
logf("TryConfigFileMigration failed; write newFile: %v", err)
return oldFile
}
logf("TryConfigFileMigration: successfully migrated: from %v to %v",
oldFile, newFile)
return newFile
}
|
