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go/src/pkg/net/dnsconfig_unix.go
Dave Cheney 7c8280c9ef all: merge NaCl branch (part 1)
See golang.org/s/go13nacl for design overview.

This CL is the mostly mechanical changes from rsc's Go 1.2 based NaCl branch, specifically 39cb35750369 to 500771b477cf from https://code.google.com/r/rsc-go13nacl. This CL does not include working NaCl support, there are probably two or three more large merges to come.

CL 15750044 is not included as it involves more invasive changes to the linker which will need to be merged separately.

The exact change lists included are

15050047: syscall: support for Native Client
15360044: syscall: unzip implementation for Native Client
15370044: syscall: Native Client SRPC implementation
15400047: cmd/dist, cmd/go, go/build, test: support for Native Client
15410048: runtime: support for Native Client
15410049: syscall: file descriptor table for Native Client
15410050: syscall: in-memory file system for Native Client
15440048: all: update +build lines for Native Client port
15540045: cmd/6g, cmd/8g, cmd/gc: support for Native Client
15570045: os: support for Native Client
15680044: crypto/..., hash/crc32, reflect, sync/atomic: support for amd64p32
15690044: net: support for Native Client
15690048: runtime: support for fake time like on Go Playground
15690051: build: disable various tests on Native Client

LGTM=rsc
R=rsc
CC=golang-codereviews
https://golang.org/cl/68150047
2014-02-25 09:47:42 -05:00

106 lines
2.6 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.
// +build darwin dragonfly freebsd linux nacl netbsd openbsd solaris
// Read system DNS config from /etc/resolv.conf
package net
type dnsConfig struct {
servers []string // servers to use
search []string // suffixes to append to local name
ndots int // number of dots in name to trigger absolute lookup
timeout int // seconds before giving up on packet
attempts int // lost packets before giving up on server
rotate bool // round robin among servers
}
// See resolv.conf(5) on a Linux machine.
// TODO(rsc): Supposed to call uname() and chop the beginning
// of the host name to get the default search domain.
func dnsReadConfig(filename string) (*dnsConfig, error) {
file, err := open(filename)
if err != nil {
return nil, &DNSConfigError{err}
}
conf := new(dnsConfig)
conf.servers = make([]string, 0, 3) // small, but the standard limit
conf.search = make([]string, 0)
conf.ndots = 1
conf.timeout = 5
conf.attempts = 2
conf.rotate = false
for line, ok := file.readLine(); ok; line, ok = file.readLine() {
f := getFields(line)
if len(f) < 1 {
continue
}
switch f[0] {
case "nameserver": // add one name server
a := conf.servers
n := len(a)
if len(f) > 1 && n < cap(a) {
// One more check: make sure server name is
// just an IP address. Otherwise we need DNS
// to look it up.
name := f[1]
switch len(ParseIP(name)) {
case 16:
name = "[" + name + "]"
fallthrough
case 4:
a = a[0 : n+1]
a[n] = name
conf.servers = a
}
}
case "domain": // set search path to just this domain
if len(f) > 1 {
conf.search = make([]string, 1)
conf.search[0] = f[1]
} else {
conf.search = make([]string, 0)
}
case "search": // set search path to given servers
conf.search = make([]string, len(f)-1)
for i := 0; i < len(conf.search); i++ {
conf.search[i] = f[i+1]
}
case "options": // magic options
for i := 1; i < len(f); i++ {
s := f[i]
switch {
case len(s) >= 6 && s[0:6] == "ndots:":
n, _, _ := dtoi(s, 6)
if n < 1 {
n = 1
}
conf.ndots = n
case len(s) >= 8 && s[0:8] == "timeout:":
n, _, _ := dtoi(s, 8)
if n < 1 {
n = 1
}
conf.timeout = n
case len(s) >= 8 && s[0:9] == "attempts:":
n, _, _ := dtoi(s, 9)
if n < 1 {
n = 1
}
conf.attempts = n
case s == "rotate":
conf.rotate = true
}
}
}
}
file.close()
return conf, nil
}