| package etchosts |
| |
| import ( |
| "bytes" |
| "fmt" |
| "io" |
| "io/ioutil" |
| "regexp" |
| ) |
| |
| type Record struct { |
| Hosts string |
| IP string |
| } |
| |
| func (r Record) WriteTo(w io.Writer) (int64, error) { |
| n, err := fmt.Fprintf(w, "%s\t%s\n", r.IP, r.Hosts) |
| return int64(n), err |
| } |
| |
| var defaultContent = []Record{ |
| {Hosts: "localhost", IP: "127.0.0.1"}, |
| {Hosts: "localhost ip6-localhost ip6-loopback", IP: "::1"}, |
| {Hosts: "ip6-localnet", IP: "fe00::0"}, |
| {Hosts: "ip6-mcastprefix", IP: "ff00::0"}, |
| {Hosts: "ip6-allnodes", IP: "ff02::1"}, |
| {Hosts: "ip6-allrouters", IP: "ff02::2"}, |
| } |
| |
| func Build(path, IP, hostname, domainname string, extraContent []Record) error { |
| content := bytes.NewBuffer(nil) |
| if IP != "" { |
| var mainRec Record |
| mainRec.IP = IP |
| if domainname != "" { |
| mainRec.Hosts = fmt.Sprintf("%s.%s %s", hostname, domainname, hostname) |
| } else { |
| mainRec.Hosts = hostname |
| } |
| if _, err := mainRec.WriteTo(content); err != nil { |
| return err |
| } |
| } |
| |
| for _, r := range defaultContent { |
| if _, err := r.WriteTo(content); err != nil { |
| return err |
| } |
| } |
| |
| for _, r := range extraContent { |
| if _, err := r.WriteTo(content); err != nil { |
| return err |
| } |
| } |
| |
| return ioutil.WriteFile(path, content.Bytes(), 0644) |
| } |
| |
| func Update(path, IP, hostname string) error { |
| old, err := ioutil.ReadFile(path) |
| if err != nil { |
| return err |
| } |
| var re = regexp.MustCompile(fmt.Sprintf("(\\S*)(\\t%s)", regexp.QuoteMeta(hostname))) |
| return ioutil.WriteFile(path, re.ReplaceAll(old, []byte(IP+"$2")), 0644) |
| } |