#!/usr/bin/perl
#########################################################################
# monitor.cgi
#
# This program must be run from cron on a Unix server.  If you don't
# know what it is, ask # your sysadmin.  It will periodically check the
# sites listed in @sites, below, to see if they are up and running.  If
# they are down, an email will be sent to your email address, advising
# you of the downtime.
#
# Written by Greg Raaum
# Copyright (c) 2000 BizDesign, Inc. All Rights Reserved.
# Selling the code for this program without prior written consent is
# expressly forbidden.
#
# This program is NOT supported.  Use at your own risk!

#########################################################################
# Instructions:
#
# Rename this file from monitor.txt to monitor.cgi or monitor.pl,
# then upload this file to your server and add it to cron, normally in
# /etc/cron.hourly or /etc/cron.quarter-hourly.  You must set permissions
# on this file to 755 after adding this to a cron directory.
#
# Define the four variables below.  Place this file in a cron directory or
# make a cron entry for this file and you are ready to go!
#
#########################################################################

##########################################################################
# Configuration Section
#########################################################################

# (1) ###################################################################
# WHAT IS YOUR EMAIL ADDRESS?

$admin_email = 'yourname@yoursite.com';


# (2) ###################################################################
# WHAT IS THE PATH TO SENDMAIL ON YOUR SERVER?

$sendmail = '/usr/sbin/sendmail';


# (3) ###################################################################
# WHAT SITES DO YOU WANT TO TRACK? (leave a comma off of the last site!)

@sites = (
          'www.yoursite1.com',
          'www.yoursite2.com',
          'www.yoursite3.com',
          'www.yoursite4.com'
          );

# (4) ###################################################################
# WHAT TIME ZONE ARE YOU IN?

$zone = "CST";


# No further editing is necessary, but feel free to play around...
#########################################################################

use IO::Socket;  # use Socket module
&check_sites;
exit(0);

sub check_sites {
# --------------------------------------------------------
# Attempts to access, 1 by 1, each site listed in @sites

   foreach $site (@sites) {
      $socket = new IO::Socket::INET( PeerAddr => $site,
                                      PeerPort => 80,
                                      Proto    => 'tcp',
                                      Type     => SOCK_STREAM, ) or &send_email($site);
      print $socket "GET / HTTP/1.0\n";
      print $socket "User-Agent: SiteMonitor\n\n";
      close ($socket);
   }
}



sub send_email {
# --------------------------------------------------------
# Sends mail to the administrator if a site is down

my ($server) = @_;

&get_date;

open(MAIL, "|$sendmail -t");
print MAIL "To: $admin_email\n";
print MAIL "From: $admin_email\n";
print MAIL "Subject: Server Down!\n\n";
print MAIL "$date\n\n";
print MAIL "The site, $server, is down.  Please check it immediately!\n";
close (MAIL);
}



sub get_date {
# --------------------------------------------------------
# Gets the date in case we need to send email
   @junk = localtime(time);
   $date = (Jan,Feb,Mar,Apr,May,Jun,Jul,Aug,Sep,Oct,Nov,Dec)[$junk[4]];
   $date .= "-" . $junk[3] . "-" . ($junk[5] + 1900);
   $date .= " " . $junk[2] . ":" . $junk[1] . " $zone";
}