#!/usr/bin/perl
#
# Use try to connect to a POP-3 server, and
# wait for the right output.
#
# For use with "mon".
#
# Arguments are "-p port -t timeout host [host...]"
#
# Adapted from "http.monitor" by
# Jim Trocki, trockij@arctic.org
#
# http.monitor written by
#
# Jon Meek
# American Cyanamid Company
# Princeton, NJ
#
# $Id: pop3.monitor,v 1.2 2005/04/17 07:42:27 trockij Exp $
#
#    Copyright (C) 1998, Jim Trocki
#
#    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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
#
use Getopt::Std;
use English;

getopts ("p:t:");
$PORT = $opt_p || 110;
$TIMEOUT = $opt_t || 30;

@failures = ();
@details = ();

foreach $host (@ARGV) {

    if (! &pop3GET($host, $PORT)) {
	push (@failures, $host);
    }
}

if (@failures == 0) {
    exit 0;
}

print join (" ", sort @failures), "\n";
print @details if (scalar @details > 0);

exit 1;


sub pop3GET {
    use Socket;
    use Sys::Hostname;

    my($Server, $Port) = @_;
    my($ServerOK, $TheContent);

    $ServerOK = 0;

    $TheContent = '';

    $Path = '/';

###############################################################
    eval {

	local $SIG{ALRM} = sub { die "Timeout Alarm" };
	alarm $TIMEOUT;
	$result = &OpenSocket($Server, $Port); # Open a connection to the server
	if ($result == 0) { # Failure to open the socket
	    return '';
	}

	$in = <S>;
	if ($in !~ /^\+OK/) {
	    alarm 0;
	    return 0;
	}

	print S "quit\r\n";

	$in = <S>;
	if ($in !~ /^\+OK/) {
	    alarm 0;
	    return 0;
	}

	$ServerOK = 1;

	close(S);
	alarm 0; # Cancel the alarm

    };

    if ($EVAL_ERROR and ($EVAL_ERROR =~ /^Timeout Alarm/)) {
	push(@details, "$host: timeout($TIMEOUT)\n");
	return 0;
    }
    return $ServerOK;

}

sub OpenSocket {
#
# Make a Berkeley socket connection between this program and a TCP port
#  on another (or this) host. Port can be a number or a named service
#
    local($OtherHostname, $Port) = @_;
    local($OurHostname, $sockaddr, $name, $aliases, $proto, $type, $len,
	  $ThisAddr, $that);
    $OurHostname = &hostname;

    ($name, $aliases, $proto) = getprotobyname('tcp');
    ($name, $aliases, $Port) = getservbyname($Port, 'tcp') unless $Port =~ /^\d+$/;
    ($name, $aliases, $type, $len, $ThisAddr) = gethostbyname($OurHostname);
    ($name, $aliases, $type, $len, $OtherHostAddr) = gethostbyname($OtherHostname);

    if (!defined $OtherHostAddr)
    {
    	push (@details, "$host: cannot resolve hostname\n");
	return undef;
    }

    my $that = sockaddr_in ($Port, $OtherHostAddr);

    if (! ($result = socket(S, &PF_INET, &SOCK_STREAM, $proto)) ||
    	(! ($result = connect(S, $that))) )
    {
	push (@details, "$host: $!\n");  return undef;
    }

    select(S); $| = 1; select(STDOUT);      # set S to be un-buffered

    return 1;                               # success
}
