#!/usr/bin/perl -w

#pop_relayd#

##This script is for adding access to relay mail 
##through a sendmail 8.9+ based e-mail server from a 
##pop/imap client being used with an arbitrary 
##outside host. It runs as a daemon, and continualy 
##checks the last line in the system mail logfile.
##When it finds evidence of an authenticated pop/imap 
##request, it adds the host name associated to the 
##request in the /etc/mail/access file allowing the 
##sendmail to relay mail from this client. A cron 
##script ran in conjuction with this daemon can reset the 
##access file each day. Probably works better if mail log
##is kept seperate from system logs.
##
##J.B. Gallagher 04/04/00 jbg@navigo.com

##System mail logfile##
$MAILLOG = "/var/log/mail";

##Sendmail access file##
$access  = "/etc/mail/access";

$killall = "/sbin/killall";

##Programs##

$makemap = "/usr/etc/makemap";
$tail    = "/bin/tail";

##Daemon stuff##

use POSIX qw(setsid);

$|=1;

&daemon;

$run_count = 0;

while(1) {


	$rundate = `/bin/date`;
	chop($rundate);

	if($run_count eq '0') {
		print STDOUT "$0 started on $rundate\n";
		print STDOUT "___________________________________\n\n";
		}


	$init = `$tail -1 $MAILLOG`;

	sleep 1;

	$i2 = `$tail -1 $MAILLOG`;

	if($i2 ne $init) {
		if($i2 =~ /ipop3d/ && $i2 =~ /Login user=/) {
			$i2 =~ s/\s+//g;
			@host = split(/host=/ , $i2);
			@hostname = split(/\[/ , $host[1]);
			$hostname[0] =~ tr/\n//d;

			open(FILE, "$access");
			while(<FILE>) {
				if($_ =~ $hostname[0]) {
					$there = '0';
					}
				}
			close(FILE);

			if($there ne '0') {
				`echo "$hostname[0]	RELAY" >>$access`;
				`$makemap hash $access < $access`;
				`$killall -HUP sendmail`;
				print STDOUT "$rundate: Added $hostname[0] to access database\n";
				}
			print STDOUT "________________________________________\n";
			}
			
		if($i2 =~ /imapd/ && $i2 =~ /Login user=/) {
			$i2 =~ s/\s+//g;
			@host = split(/host=/ , $i2);
			@hostname = split(/\[/ , $host[1]);
			$hostname[0] =~ tr/\n//d;

			open(FILE, "$access");
			while(<FILE>) {
				if($_ =~ $hostname[0]) {
					$there = '0';
					}
				}
			close(FILE);

			if($there ne '0') {
				`echo "$hostname[0]	RELAY" >>$access`;
				`$makemap hash $access < $access`;
				`$killall -HUP sendmail`;
				print STDOUT "$rundate: Added $hostname[0] to access database\n";
				}
			print STDOUT "________________________________________\n";
			}

		#RESET dummy variables#
		$there = 1;
		}
		$run_count++;
	}

sub daemon {

	$date = `date +"%y%m%d"`;
	chop($date);
	$logfile = "/var/log/access-relay.$date";

	chdir '/' or die "Can't chdir to /: $!";
	umask 0;
	open STDIN, '/dev/null'   or die "Can't read /dev/null: $!";
	open STDOUT, ">>$logfile" or die "Can't write to $logfile: $!";
	open STDERR, '/dev/null' or die "Can't write to err: $!";
	defined(my $pid = fork)   or die "Can't fork: $!";
	exit if $pid;
	setsid                    or die "Can't start a new session: $!";
	}