#!/usr/bin/perl

my $DEBUG=0;

use strict;

my $domain = "wolfteck.com";
my $host = $ARGV[0];
my $fqdn = "$host.$domain";
my $d='/etc/tinydns/root';
my $ttl = 1800;
my $e;

unless ($e = $ENV{SSH_CONNECTION}){
   die "cannot get connection environment variable\n";
}

unless ($host) {
   die "did not receive hostname\n";
}

if (my ($client_ip) = $e =~ /^(\S+)/){
   my $f=qq[$d/dynamic.data];
   my $t=$f . 'tmp';
   my $flag = undef;
   my $old_ip = undef;
   open(READ, "<$f") or die "cannot read file $f. $!\n";
   my $dyndata;
   while(<READ>) {
      if($_ =~ /^.$fqdn\:(\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}).*/) {  # If line has our fqdn
         $old_ip = $_;
         $old_ip =~ s/.*\:(\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3})\:.*/$1/;  # Grab our old IP address
         chomp($old_ip);
         print "old address was: $old_ip\nnew address is: $client_ip\n";
         $flag++;
      }
      print "olip -- $old_ip\n" if $DEBUG;
      print "orig -- $_\n" if $DEBUG;
      if($old_ip) { $_ =~ s/$old_ip/$client_ip/ }                       # Replace old IP with new IP
      print "newl -- $_\n" if $DEBUG;
      $dyndata .= $_;
   }
   close(READ);
   if(!$flag) {$dyndata .= qq[=$fqdn:${client_ip}:$ttl\n]}
   open(F, ">$t") or die "cannot open file $t for writing. $!\n";
   print F $dyndata;
   close F or die "cannot close file $t. $!\n";
   rename $t, $f or die "cannot rename file $t to $f. $!\n";
   chdir($d) or die "cannot chdir to $d. $!\n";
   exec '/usr/bin/make -s';

}
else {
   warn "cannot get client ip\n";
   exit 1;
}