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#!/usr/bin/perl -w
#
# Module: vyatta_update_resolv.pl
#
# **** License ****
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License version 2 as
# published by the Free Software Foundation.
#
# This program is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
# General Public License for more details.
#
# This code was originally developed by Vyatta, Inc.
# Portions created by Vyatta are Copyright (C) 2007 Vyatta, Inc.
# All Rights Reserved.
#
# Author: Marat Nepomnyashy
# Date: December 2007
# Description: Script to update '/etc/resolv.conf' on commit of 'system domain-search domain' config.
#
# **** End License ****
#
use strict;
use lib "/opt/vyatta/share/perl5/";
use Getopt::Long;
use Vyatta::Config;
my $dhclient_script = 0;
my $config_mode = 0;
GetOptions("dhclient-script=i" => \$dhclient_script,
"config-mode=i" => \$config_mode,
);
my $vc = new Vyatta::Config();
$vc->setLevel('system');
my @domains;
my $domain_name = undef;
my $disable_dhcp_nameservers = undef;
if ($config_mode == 1) {
$disable_dhcp_nameservers = $vc->exists('disable-dhcp-nameservers');
} else {
$disable_dhcp_nameservers = $vc->existsOrig('disable-dhcp-nameservers');
}
if ($dhclient_script == 1) {
@domains = $vc->returnOrigValues('domain-search domain');
$domain_name = $vc->returnOrigValue('domain-name');
} else {
@domains = $vc->returnValues('domain-search domain');
$domain_name = $vc->returnValue('domain-name');
}
if ($dhclient_script == 0 && @domains > 0 && $domain_name && length($domain_name) > 0) {
my @loc;
if ($vc->returnOrigValues('domain-search domain') > 0) {
@loc = ["system","domain-name"];
}
else {
@loc = ["system","domain-search","domain"];
}
Vyatta::Config::outputError(@loc,"System configuration error. Both \'domain-name\' and \'domain-search\' are specified, but only one of these mutually exclusive parameters is allowed.");
exit(1);
}
my $doms = '';
foreach my $domain (@domains) {
if (length($doms) > 0) {
$doms .= ' ';
}
$doms .= $domain;
}
# add domain names received from dhcp client to domain search in /etc/resolv.conf if domain-name not set in CLI
if (!defined($domain_name)) {
my @dhcp_interfaces_resolv_files = `ls /etc/ | grep resolv.conf.dhclient-new`;
if ($#dhcp_interfaces_resolv_files >= 0) {
for my $each_file (@dhcp_interfaces_resolv_files) {
chomp $each_file;
my $find_search = `grep "^search" /etc/$each_file 2> /dev/null | wc -l`;
if ($find_search == 1) {
my $search_string = `grep "^search" /etc/$each_file`;
my @dhcp_domains = split(/\s+/, $search_string, 2);
my $dhcp_domain = $dhcp_domains[1];
chomp $dhcp_domain;
$doms .= ' ' . $dhcp_domain;
}
}
}
}
my $search = '';
if (length($doms) > 0) {
$search = "search\t\t$doms\t\t#line generated by $0\n";
}
my $domain = '';
if ($domain_name && length($domain_name) > 0) {
$domain = "domain\t\t$domain_name\t\t#line generated by $0\n";
}
# update /etc/resolv.conf with name-servers received from dhcp client, done when this script is called
# with either the dhclient-script (on DHCP changes) or config-mode (disable-dhcp-nameservers) options.
if (($dhclient_script == 1) || ($config_mode == 1)) {
my @current_dhcp_nameservers;
my $restart_ntp = 0;
# code below to add new name-servers received from dhcp client, but only if disable-dhcp-nameservers
# hasn't been enabled.
my @dhcp_interfaces_resolv_files = `ls /etc/ | grep resolv.conf.dhclient-new`;
if ($#dhcp_interfaces_resolv_files >= 0) {
my $ns_count = 0;
for my $each_file (@dhcp_interfaces_resolv_files) {
chomp $each_file;
my $find_nameserver = `grep nameserver /etc/$each_file 2> /dev/null | wc -l`;
if ($find_nameserver > 0) {
my @nameservers = `grep nameserver /etc/$each_file`;
for my $each_nameserver (@nameservers) {
my @nameserver = split(/ /, $each_nameserver, 2);
my $ns = $nameserver[1];
chomp $ns;
$current_dhcp_nameservers[$ns_count] = $ns;
$ns_count++;
my @search_ns_in_resolvconf = `grep $ns /etc/resolv.conf`;
my $ns_in_resolvconf = 0;
if (@search_ns_in_resolvconf > 0) {
foreach my $ns_resolvconf (@search_ns_in_resolvconf) {
my @resolv_ns = split(/\s+/, $ns_resolvconf);
my $final_ns = $resolv_ns[1];
chomp $final_ns;
if ($final_ns eq $ns) {
$ns_in_resolvconf = 1;
}
}
}
if (($ns_in_resolvconf == 0) && !($disable_dhcp_nameservers)) {
open (my $rf, '>>', '/etc/resolv.conf')
or die "$! error trying to overwrite";
print $rf "nameserver\t$ns\t\t#nameserver written by $0\n";
close $rf;
$restart_ntp = 1;
}
}
}
}
}
# code below to remove old name-servers from /etc/resolv.conf that were not received in this response
# from dhcp-server, or to remove previous dhcp supplied name-servers if disable-dhcp-nameservers has
# been enabled.
my @nameservers_dhcp_in_resolvconf = `grep 'nameserver written' /etc/resolv.conf`;
my @dhcp_nameservers_in_resolvconf;
my $count_nameservers_in_resolvconf = 0;
for my $count_dhcp_nameserver (@nameservers_dhcp_in_resolvconf) {
my @dhcp_nameserver = split(/\t/, $count_dhcp_nameserver, 3);
$dhcp_nameservers_in_resolvconf[$count_nameservers_in_resolvconf] = $dhcp_nameserver[1];
$count_nameservers_in_resolvconf++;
}
if (($#current_dhcp_nameservers < 0) || ($disable_dhcp_nameservers)) {
for my $dhcpnameserver (@dhcp_nameservers_in_resolvconf) {
my $cmd = "sed -i '/$dhcpnameserver\t/d' /etc/resolv.conf";
system($cmd);
$restart_ntp = 1;
}
} else {
for my $dhcpnameserver (@dhcp_nameservers_in_resolvconf) {
my $found = 0;
for my $currentnameserver (@current_dhcp_nameservers) {
if ($dhcpnameserver eq $currentnameserver){
$found = 1;
}
}
if ($found == 0) {
my $cmd = "sed -i '/$dhcpnameserver\t/d' /etc/resolv.conf";
system($cmd);
$restart_ntp = 1;
}
}
}
if ($restart_ntp == 1) {
# this corresponds to what is done in name-server/node.def as a fix for bug 1300
my $cmd_ntp_restart = "if [ -f /etc/ntp.conf ] && grep -q '^server' /etc/ntp.conf; then /usr/sbin/invoke-rc.d ntp restart >&/dev/null; fi &";
system($cmd_ntp_restart);
}
}
# The following will re-write '/etc/resolv.conf' line by line,
# replacing the 'search' specifier with the latest values,
# or replacing the 'domain' specifier with the latest value.
my @resolv;
if (-e '/etc/resolv.conf') {
open (my $f, '<', '/etc/resolv.conf')
or die("$0: Error! Unable to open '/etc/resolv.conf' for input: $!\n");
@resolv = <$f>;
close ($f);
}
my $foundSearch = 0;
my $foundDomain = 0;
open (my $r, '>', '/etc/resolv.conf')
or die("$0: Error! Unable to open '/etc/resolv.conf' for output: $!\n");
foreach my $line (@resolv) {
if ($line =~ /^search\s/) {
$foundSearch = 1;
if (length($search) > 0) {
print $r $search;
}
} elsif ($line =~ /^domain\s/) {
$foundDomain = 1;
if (length($domain) > 0) {
print $r $domain;
}
} else {
print $r $line;
}
}
if ($foundSearch == 0 && length($search) > 0) {
print $r $search;
}
if ($foundDomain == 0 && length($domain) > 0) {
print $r $domain;
}
close ($r);
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