1 package util
2
3 import (
4 "bytes"
5 "crypto/md5"
6 "fmt"
7 "io"
8 "io/ioutil"
9 "os"
10 "os/exec"
11 )
12
13 func WriteConfig(orig, dest string, data []byte) (bool, error) {
14
15 if _, err := os.Stat(orig); !os.IsNotExist(err) {
16 hasher := md5.New()
17 f, err := os.Open(orig)
18 if err != nil {
19 return false, err
20 }
21 defer f.Close()
22 if _, err := io.Copy(hasher, f); err != nil {
23 return false, err
24 }
25 oldHash := hasher.Sum(nil)[:16]
26
27 hasher = md5.New()
28 hasher.Write(data)
29 newHash := hasher.Sum(nil)
30
31 if bytes.Equal(oldHash, newHash) {
32 return false, nil
33 }
34 f.Close()
35 }
36
37 err := ioutil.WriteFile(dest, data, 0644)
38 if err != nil {
39 return false, err
40 }
41 return true, nil
42 }
43
44 func TestConfig(f string) error {
45 var stderr bytes.Buffer
46 dnsmasqBinary, err := exec.LookPath("dnsmasq")
47 if err != nil {
48 return err
49 }
50 cmd := &exec.Cmd{
51 Path: dnsmasqBinary,
52 Args: []string{"dnsmasq", "--test", "--conf-file=" + f},
53 Stderr: &stderr,
54 }
55 err = cmd.Run()
56 if err != nil {
57 err = fmt.Errorf(string(stderr.Bytes()))
58 }
59 return err
60 }
61
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