1 // Copyright 2009 The Go Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style
3 // license that can be found in the LICENSE file.
5 // Read static host/IP entries from /etc/hosts.
14 const cacheMaxAge = 5 * time.Minute
16 // hostsPath points to the file with static IP/address entries.
17 var hostsPath = "/etc/hosts"
22 byName map[string][]string
23 byAddr map[string][]string
31 if len(hosts.byName) == 0 || now.After(hosts.expire) || hosts.path != hp {
32 hs := make(map[string][]string)
33 is := make(map[string][]string)
35 if file, _ = open(hp); file == nil {
38 for line, ok := file.readLine(); ok; line, ok = file.readLine() {
39 if i := byteIndex(line, '#'); i >= 0 {
44 if len(f) < 2 || ParseIP(f[0]) == nil {
47 for i := 1; i < len(f); i++ {
49 hs[h] = append(hs[h], f[0])
50 is[f[0]] = append(is[f[0]], h)
53 // Update the data cache.
54 hosts.expire = time.Now().Add(cacheMaxAge)
62 // lookupStaticHost looks up the addresses for the given host from /etc/hosts.
63 func lookupStaticHost(host string) []string {
67 if len(hosts.byName) != 0 {
68 if ips, ok := hosts.byName[host]; ok {
75 // lookupStaticAddr looks up the hosts for the given address from /etc/hosts.
76 func lookupStaticAddr(addr string) []string {
80 if len(hosts.byAddr) != 0 {
81 if hosts, ok := hosts.byAddr[addr]; ok {