gcc/libgo/go/net/hosts.go
Ian Lance Taylor 7a9389330e Add Go frontend, libgo library, and Go testsuite.
gcc/:
	* gcc.c (default_compilers): Add entry for ".go".
	* common.opt: Add -static-libgo as a driver option.
	* doc/install.texi (Configuration): Mention libgo as an option for
	--enable-shared.  Mention go as an option for --enable-languages.
	* doc/invoke.texi (Overall Options): Mention .go as a file name
	suffix.  Mention go as a -x option.
	* doc/frontends.texi (G++ and GCC): Mention Go as a supported
	language.
	* doc/sourcebuild.texi (Top Level): Mention libgo.
	* doc/standards.texi (Standards): Add section on Go language.
	Move references for other languages into their own section.
	* doc/contrib.texi (Contributors): Mention that I contributed the
	Go frontend.
gcc/testsuite/:
	* lib/go.exp: New file.
	* lib/go-dg.exp: New file.
	* lib/go-torture.exp: New file.
	* lib/target-supports.exp (check_compile): Match // Go.

From-SVN: r167407
2010-12-03 04:34:57 +00:00

69 lines
1.4 KiB
Go

// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Read static host/IP entries from /etc/hosts.
package net
import (
"os"
"sync"
)
const cacheMaxAge = int64(300) // 5 minutes.
// hostsPath points to the file with static IP/address entries.
var hostsPath = "/etc/hosts"
// Simple cache.
var hosts struct {
sync.Mutex
data map[string][]string
time int64
path string
}
func readHosts() {
now, _, _ := os.Time()
hp := hostsPath
if len(hosts.data) == 0 || hosts.time+cacheMaxAge <= now || hosts.path != hp {
hs := make(map[string][]string)
var file *file
if file, _ = open(hp); file == nil {
return
}
for line, ok := file.readLine(); ok; line, ok = file.readLine() {
if i := byteIndex(line, '#'); i >= 0 {
// Discard comments.
line = line[0:i]
}
f := getFields(line)
if len(f) < 2 || ParseIP(f[0]) == nil {
continue
}
for i := 1; i < len(f); i++ {
h := f[i]
hs[h] = append(hs[h], f[0])
}
}
// Update the data cache.
hosts.time, _, _ = os.Time()
hosts.path = hp
hosts.data = hs
file.close()
}
}
// lookupStaticHosts looks up the addresses for the given host from /etc/hosts.
func lookupStaticHost(host string) []string {
hosts.Lock()
defer hosts.Unlock()
readHosts()
if len(hosts.data) != 0 {
if ips, ok := hosts.data[host]; ok {
return ips
}
}
return nil
}