chrony/contrib/DNSchrony/DNSchrony.pl
2009-10-28 17:53:33 +01:00

583 lines
15 KiB
Perl
Executable file

#!/usr/bin/perl
# Copyright (C) Paul Elliott 2002
my($copyrighttext) = <<'EOF';
# Copyright (C) Paul Elliott 2002
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
# SEE COPYING FOR DETAILS
EOF
#modules we use.
use Socket;
use Getopt::Std;
use Net::DNS;
use Tie::Syslog;
use File::Temp qw/ :mktemp /;
use File::Copy;
local($res) = new Net::DNS::Resolver;
#dns lookup of IP address.
#returns ip or errorstring.
sub gethostaddr($) #get ip address from host
{
my($host) = shift;
$query = $res->search($host);
if ($query) {
foreach $rr ($query->answer) {
next unless $rr->type eq "A";
print $rr->address, "\n" if $pedebug;
return $rr->address;
}
} else {
print "query failed: ", $res->errorstring, "\n" if $pedebug;
return $res->errorstring;
}
}
#send messages to syslog
sub Log($$)
{
if ($log) {
my($level) = shift;
my($mess) =shift;
tie *MYLOG, 'Tie::Syslog',$level,$0,'pid','unix';
print MYLOG $mess;
untie *MYLOG;
}
}
#send message to output or syslog
#and die.
sub BadDie($)
{
my($myerr) =$!;
my($mess)=shift;
if($log){
tie *MYLOG, 'Tie::Syslog','local0.err',$0,'pid','unix';
print MYLOG $mess;
print MYLOG $myerr;
untie *MYLOG;
} else {
print "$mess\n$myerr\n";
}
die $mess;
}
sub isIpAddr($) #return true if looks like ip address
{
my($ip) = shift;
return 1 if ( $ip =~ m/$ipOnlyPAT/ );
return 0;
}
sub isHostname($) #return true if looks like ip address
{
my($ip) = shift;
return 1 if ( $ip =~ m/$hostnameOnlyPAT/ );
return 0;
}
#send commands to chronyc by piping.
sub chronyc($) #send commands to chronyc
{
my($command) = shift;
my($err) = "/var/tmp/chronyc.log";
my($chronyP) = "/usr/local/bin/chronyc";
open(CHRONY, "| $chronyP 1>$err 2>&1");
print CHRONY "$passwd$command\n";
close(CHRONY);
Log('local0.info',"chronyc command issued=$command");
#look at status lines till return bad.
open( IN, "<$err");
my($status);
while (<IN>) {
$status = $_;
unless ( m/\A200 OK/ ) {
last;
}
}
$status ="" if ( $status =~ m/\A200 OK/ );
close(IN);
unlink $err;
Log('local0.info',"chronyc results=$status");
return $status;
}
#common patterns
# an ip address patern
local($ipPAT) = qr/\d{1,3}(?:\.\d{1,3}){3}/;
# an hostname pattern
local($hostnamePAT) = qr/\w+(?:\.\w+)*/;
#line with hostname only
local($hostnameOnlyPAT) = qr/\A$hostnamePAT\Z/;
#line with ip address only
local($ipOnlyPAT) =qr/\A$ipPAT\Z/;
#options hash
my(%opts);
getopts('nuadslPSC', \%opts);
local($log) = ( $opts{'l'} ) ? 1 : 0;
my($offline) = !( $opts{'n'} ) ;
my($offlineS) = ( $opts{'n'} ) ? " " : " offline" ;
# paul elliotts secret debug var. no one will ever find out about it.
local($pedebug)=( ($ENV{"PAULELLIOTTDEBUG"}) or ($opts{P}) );
if ($opts{C}) {
print $copyrighttext;
exit 0;
}
print <<"EOF" unless $opts{'S'};
$0, Copyright (C) 2002 Paul Elliott
$0 comes with ABSOLUTELY NO WARRANTY; for details
invoke $0 -C. This is free software, and you are welcome
to redistribute it under certain conditions; invoke $0 -C
for details.
EOF
local($passwd);
# password to send to chronyc
my($pl) = $ENV{"CHRONYPASSWORD"};
#password comand to send to chronyc
if ( $pl ) {
$passwd = "password $pl\n";
} else {
$passwd = "";
}
print "passwd=$passwd\n" if ($pedebug);
my(%host2ip);
# hash of arrays. host2ip{$host}[0] is ip address for this host
# host2ip{$host}[1] is rest of paramenters for this host exc offline.
#if debuging do chrony.conf in current directory.
my($listfile) =( ($pedebug) ? "./chrony.conf" : "/etc/chrony.conf") ;
# This section reads in the old data about
# hostnames IP addresses and server parameters
# data is stored as it would be in chrony.conf
# file i.e.:
#># HOSTNAME
#>server IPADDR minpoll 5 maxpoll 10 maxdelay 0.4 offline
#
# the parameter offline is omitted if the -n switch is specified.
# first parameter is the filename of the file usually
# is /etc/DNSchrony.conf
# this is where we store the list of DNS hosts.
# hosts with static IP address shold be kept in chrony.conf
# this is header that marks dnyamic host section
my($noedithead)=<<'EOF';
## DNSchrony dynamic dns server section. DO NOT EDIT
## per entry FORMAT:
## |--------------------------------------------|
## |#HOSTNAME |
## |server IP-ADDRESS extra-params [ offline ] |
## |--------------------------------------------|
EOF
#patern that recognizes above.
my($noeditheadPAT) =
qr/\#\#\s+DNSchrony\s+dynamic\s+dns\s+server\s+section\.\s+DO\s+NOT\s+EDIT\s*/;
#end of header marker.
my($noeditheadend)=<<'EOF';
## END OF DNSchrony dynamic dns server section.
EOF
#pattern that matches above.
my($noeditheadendPAT)=
qr/\#\#\s+END\s+OF\s+DNSchrony\s+dynamic\s+dns\s+server\s+section.\s*/;
#array to hold non dns portion of chrony.conf
my(@chronyDconf);
my($ip);
my($rest);
my($host);
# for each entry in the list of hosts....
open(READIN, "<$listfile") or BadDie("Can not open $listfile");
# read till dynamic patern read save in @chronyDconf
while ( <READIN> ) {
my($line) = $_;
last if ( m/\A$noeditheadPAT\Z/ );
push(@chronyDconf,$line);
}
while ( <READIN> ) {
#end loop when end of header encountered
last if ( m/\A$noeditheadendPAT/ );
# parse the line giving ip address, extra pamamters, and host
#do host comment line first
($host) = m{
\A\#\s*
($hostnamePAT)
\s*\z
}xio;
#no match skip this line.
next unless ( $host );
# read next line
$_ = <READIN>;
# parse out ip address extra parameters.
($ip,$rest) =
m{
\A
\s*
server #server comand
\s+
($ipPAT) #ip address
(?ixo: \s )
\s*
(
(?(?!
(?iox: offline )? #skip to offline #
\s* #or #
\Z
).)*
)
(?ixo:
\s*
(?ixo: offline )? #consume to #
\s*
\Z
)
}xio ;
#if failure again.
next unless ( $ip );
$rest =~ s/\s*\z//; #remove trail blanks
#from parameters
# store the data in the list
# key is host name value is
# array [0] is ip address
# [1] is other parameters
$host2ip{$host} = [$ip,$rest] ;
print "ip=$ip rest=$rest host=$host<\n" if $pedebug;
}
#read trailing line into @chronyDconf
while ( <READIN> ) {
push(@chronyDconf,$_);
}
close(READIN) or BadDie("can not close $listfile");
#if the add command:
# command can be HOST=IPADDRESS OTHER_PARAMETERS
# means add the server trust the ip address geven with out a dns lookup
# good for when dns is down but we know the ip addres
# or
# HOST OTHER_PARAMETERS
#we lookup the ip address with dns.
if ($opts{'a'}) {
my($param)= shift;
# parse the param is it hostname
if ( ($host,$ip) = $param =~ m/\A($hostnamePAT)=($ipPAT)\Z/ ) {
printf "ip=$ip host=$host\n" if ($pedebug);
} else {
$host = $param;
# get the ip address
$ip = gethostaddr($host);
if ( ! isIpAddr($ip) or ! isHostname($host) ) {
print "query failed: ", $ip, "host=$host\n" if $pedebug;
exit 1;
}
}
printf "ip=$ip host=$host\n" if ($pedebug);
# add the server using chronyc
my($status) = chronyc("add server $ip $rest");
if ($status) { #chronyc error
print "chronyc failed, status=$status\n";
exit 1;
}
# get rest of arguements
$rest = join( ' ', @ARGV);
print "rest=$rest\n" if ($pedebug);
#save node in hash
$host2ip{$host} = [$ip,$rest] ;
print "ip=$ip rest=$rest host=$host<\n" if $pedebug;
}
#delete command if arguement is ip address
#just delete it
#if a hostname look it up
#then delete it.
if ($opts{'d'}) {
$host = shift;
#get host name is it ap address
if ( isIpAddr($host) ) { # if ip address
my($hostIT);
my($found) =0;
foreach $hostIT (keys(%host2ip) ) { #search for match
if ( $host2ip{$hostIT}[0] eq $host) {
$found=1; #record match
}
} #end of search
if ($found) { #if match found
my($status) = chronyc("delete $host"); #chronyc
if ($status) { #chronyc error
print "chronyc failed, status=$status\n";
exit 1;
} else { #reiterate
foreach $hostIT (keys(%host2ip) ) {
if ( $host2ip{$hostIT}[0] eq $host) {
delete $host2ip{$hostIT}; #deleting match hosts
}
}
}
}
} else { #else not ip address
#must be hostname
if ( ! $host2ip{$host} ) {
print "No such host as $host listed\n";
exit 1;
}
#get ip address
$ip=gethostaddr($host);
if ( ! isIpAddr($ip) ) { #no ip address
print "query failed: ", $ip, "\n" if $pedebug;
exit 1;
}
printf "ip=$ip host=$host\n" if ($pedebug);
my($listed_host_ip) = $host2ip{$host}[0]; # get the ip address saved
if ( $ip ne $listed_host_ip) {
print
"Info: listed host ip=>$listed_host_ip".
"< is different from DNS ip=>$ip<\n";
$ip = $listed_host_ip;
}
# delete the server
my($status) = chronyc("delete $listed_host_ip\n");
if ($status) {
print "chronyc failed, status=$status\n";
exit 1;
}
#delete table entry
delete$host2ip{$host};
}
}
#update for each host who's dns ip address has changed
#delete the old server and add the new. update the record.
if ($opts{'u'}) {
my($command);
my(%prospective); # store new IP address we
#are thinking of changing.
Log('local0.info',
"Now searching for modified DNS entries.");
foreach $host (keys(%host2ip)) { #for each listed host
my($old_ip) = $host2ip{$host}[0]; #get old ip
$rest = $host2ip{$host}[1]; #extra params
$ip = gethostaddr($host); #get new ip from dns
#if error
if ( ! isIpAddr($ip) or ! isHostname($host) ) {
print "query failed: ", $ip, "host=$host\n";
Log('local0.err',"query failed: ". $ip . "host=$host");
exit 1;
}
next if($ip eq $old_ip); #if ip not changed, skip
Log('local0.info',"Ip address for $host has changed. Old IP address=".
"$old_ip, new IP address=$ip");
# add command to delete old host, add the new.
$command = $command . "delete $old_ip\n" .
"add server $ip $rest\n";
# we are now thinking about changing this host ip
$prospective{$host} = [$ip,$rest];
}
# submit all the accumulated chronyc commands if any.
if ($command) {
$status = chronyc($command);
if ($status) {
print "chronyc failed, status=$status\n";
Log('local0.err',"query failed: ". $ip . "host=$host");
exit 1;
}
} else { #if no commands exit
exit 0; #because no rewrite of file needed
}
#copy prospective modifications back into main table.
#we now know that all these mods were done with chronyc
foreach $host (keys(%prospective)) {
my($ip) = $prospective{$host}[0];
$rest = $prospective{$host}[1];
$host2ip{$host} = [$ip,$rest];
}
}
#starting for each entry we have read in from the old list
# add the server in chronyc
# this option is seldom used.
if ($opts{'s'}) {
my($command)="";
foreach $host (keys(%host2ip)) {
$command = $command . "add server $host2ip{$host}[0] ".
"$host2ip{$host}[1]\n";
}
my($status) = chronyc($command);
if ($status) {
print "chronyc failed, status=$status\n";
exit 1;
}
}
# write out the data file in format
#># HOSTNAME
#>server IPADDRESS extra parameters [offline]
# offline is omitted if -n switch is specified.
my(@value);
my($such);
{
# to start out we write to temporary file.
(my($writeout) , my($outname)) = mkstemp( "${listfile}.outXXXXXXX");
$outname or BadDie("can not open for $listfile");
# save the chrony.conf part!
# and write the DYNAMIC header
print $writeout @chronyDconf, $noedithead;
# for each entry
foreach $host (keys(%host2ip) ){
#write the record
# write the comment that indicates the hostname
# and the server command.
print $writeout
"\# $host\nserver $host2ip{$host}[0] $host2ip{$host}[1]${offlineS}\n" ;
print
"server $host2ip{$host}[0] $host2ip{$host}[1]${offlineS}\# $host\n"
if $pedebug;
}
#WRITE THE end of dnyamic marker comment
print $writeout $noeditheadend;
# close the output file which was a temporary file.
close($writeout) or BadDie("can not close $outname");
# we now begin a intracate dance to make the the temporary
# the main chrony.conf
#
# if there is a chrony.conf.BAK save it to a temporary.
# rename chrony.conf to chrony.conf.BAK
# rename the temporary to chrony.conf
# if there already was a chrony.conf.BAK, unlink the copy of this.
my($backname) = "$listfile\.BAK";
my($backplain) = ( -f $backname );
my($saveback);
#if chrony.conf.BAK exists rename to a temporary.
if ($backplain ) {
$saveback = mktemp("${backname}.bakXXXXXXX");
move($backname,$saveback) or
BadDie "unable to move $backname to $savename";
}
# rename old chrony.conf to chrony.conf.BAK
move($listfile,$backname) or
BadDie "unable to move $listfile to $backname";
# rename our output to chrony.conf
move($outname,$listfile) or
BadDie "unable to move $outname to $listfile";
#if there was a temporary chrony.conf.BAK that we saved to temp
#unlink it
unlink($saveback) or BadDie "unable to unlink $saveback" if($backplain);
}