gcc/libgo/go/net/dnsconfig_unix.go
Ian Lance Taylor f8d9fa9e80 libgo, compiler: Upgrade libgo to Go 1.4, except for runtime.
This upgrades all of libgo other than the runtime package to
the Go 1.4 release.  In Go 1.4 much of the runtime was
rewritten into Go.  Merging that code will take more time and
will not change the API, so I'm putting it off for now.

There are a few runtime changes anyhow, to accomodate other
packages that rely on minor modifications to the runtime
support.

The compiler changes slightly to add a one-bit flag to each
type descriptor kind that is stored directly in an interface,
which for gccgo is currently only pointer types.  Another
one-bit flag (gcprog) is reserved because it is used by the gc
compiler, but gccgo does not currently use it.

There is another error check in the compiler since I ran
across it during testing.

gotools/:
	* Makefile.am (go_cmd_go_files): Sort entries.  Add generate.go.
	* Makefile.in: Rebuild.

From-SVN: r219627
2015-01-15 00:27:56 +00:00

97 lines
2.5 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 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}
}
defer file.close()
conf := &dnsConfig{
ndots: 1,
timeout: 5,
attempts: 2,
}
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
if len(f) > 1 && len(conf.servers) < 3 { // small, but the standard limit
// One more check: make sure server name is
// just an IP address. Otherwise we need DNS
// to look it up.
if parseIPv4(f[1]) != nil {
conf.servers = append(conf.servers, f[1])
} else if ip, _ := parseIPv6(f[1], true); ip != nil {
conf.servers = append(conf.servers, f[1])
}
}
case "domain": // set search path to just this domain
if len(f) > 1 {
conf.search = []string{f[1]}
}
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 hasPrefix(s, "ndots:"):
n, _, _ := dtoi(s, 6)
if n < 1 {
n = 1
}
conf.ndots = n
case hasPrefix(s, "timeout:"):
n, _, _ := dtoi(s, 8)
if n < 1 {
n = 1
}
conf.timeout = n
case hasPrefix(s, "attempts:"):
n, _, _ := dtoi(s, 9)
if n < 1 {
n = 1
}
conf.attempts = n
case s == "rotate":
conf.rotate = true
}
}
}
}
return conf, nil
}
func hasPrefix(s, prefix string) bool {
return len(s) >= len(prefix) && s[:len(prefix)] == prefix
}