#!/usr/bin/perl
# check_email.pl - nagios plugin 
# 
#
# Copyright (C) 2003 andrew fresh
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the BSD License.
#
# Report bugs to: andrew@mad-techies.org
# 
# 11.15.2003 Version 1.0
#
# $RedRiver: check_email,v 1.2 2006/09/27 18:54:27 andrew Exp $

use POSIX;
use lib "/usr/local/libexec/nagios"  ;
use utils qw($TIMEOUT %ERRORS &print_revision &support);

use strict;
use warnings;
use diagnostics;

use Net::SMTP;

use Net::POP3;


use Getopt::Long;
Getopt::Long::Configure('bundling');

my $PROGNAME = "check_email";


my $status;
my $state = "UNKNOWN";
my $answer = "";
my $opt_h ;
my $opt_V ;

my $hostname;

my $smtp_server;
my $from_address = "Nagios <>";
my $to_address;

my $pop_server;
my $pop_user;
my $pop_password;

my $wait_time = 1;


# Just in case of problems, let's not hang Nagios
$SIG{'ALRM'} = sub {
     print ("ERROR: No response from $hostname (alarm timeout)\n");
     exit $ERRORS{"UNKNOWN"};
};
alarm($TIMEOUT);



#Option checking
$status = GetOptions(
		"V"   => \$opt_V, "version"    => \$opt_V,
		"h"   => \$opt_h, "help"       => \$opt_h,
		"H=s" => \$hostname, "hostname=s" => \$hostname,
		"S=s" => \$smtp_server, "smtpserver=s" => \$smtp_server,
		"P=s" => \$pop_server, "popserver=s" => \$pop_server,
		"t=s" => \$to_address, "to=s" => \$to_address,
		"f=s" => \$from_address, "from=s" => \$from_address,
		"u=s" => \$pop_user, "username=s" => \$pop_user,
		"p=s" => \$pop_password, "password=s" => \$pop_password,
		"w:i" => \$wait_time, "wait=i" => \$wait_time,
		);
		
if ($status == 0)
{
	print_help() ;
	exit $ERRORS{'OK'};
}


if ($opt_V) {
	print_revision($PROGNAME,'$Revision: 1.3 $ ');
	exit $ERRORS{'OK'};
}

if ($opt_h) {
	print_help();
	exit $ERRORS{'OK'};
}


if (! utils::is_hostname($hostname) || ! defined $pop_user || ! defined $pop_password ){
	usage();
	exit $ERRORS{"UNKNOWN"};
}

### Actions go here

my $subject = scalar localtime;
my $received_subject;

$smtp_server ||= $hostname;
$pop_server ||= $hostname;
$to_address ||= ( $pop_user =~ /\@/ ) ? $pop_user : "$pop_user\@$smtp_server";

my $smtp = Net::SMTP->new($smtp_server) || done('CRITICAL', "Couldn't connect to SMTP Server $smtp_server");

$smtp->mail($from_address) || done('WARNING', "Couldn't specify smtp from address $from_address on SMTP server $smtp_server");
$smtp->to($to_address) || done('CRITICAL', "Couldn't specify smtp to address $to_address on SMTP server $smtp_server");
    
$smtp->data() || done('CRITICAL', "Couldn't begin data on SMTP server $smtp_server");
$smtp->datasend("To: $to_address\n") || done('CRITICAL', "Couldn't smtp datasend To: header on SMTP server $smtp_server");
$smtp->datasend("From: $from_address\n") || done('CRITICAL', "Couldn't smtp datasend From: header on SMTP server $smtp_server");
$smtp->datasend("Subject: $subject\n") || done('CRITICAL', "Couldn't smtp datasend Subject: header on SMTP server $smtp_server");
$smtp->datasend("\n") || done('CRITICAL', "Couldn't smtp datasend blank line on SMTP server $smtp_server");
$smtp->datasend("A simple test message sent on $subject\n") || done('CRITICAL', "Couldn't smtp datasend message body on SMTP server $smtp_server");
$smtp->dataend() || done('CRITICAL', "Couldn't smtp dataend on SMTP server $smtp_server");
    
$smtp->quit || done('CRITICAL', "Couldn't smtp quit on SMTP server $smtp_server");

sleep $wait_time;

my $pop = Net::POP3->new($pop_server) || done('CRITICAL', "Couldn't connect to POP server $pop_server");

$pop->user($pop_user) || done('CRITICAL', "POP username $pop_user failed on POP server $pop_server");
$pop->pass($pop_password) || done('CRITICAL', "POP password for $pop_user failed on POP server $pop_server");

my $messages = $pop->list() || done('CRITICAL', "Couldn't get message list from POP server $pop_server");

foreach my $message (sort { $a <=> $b } keys %{ $messages } ) {
	#print $message;
	#print "\n";
	my $lines = $pop->get($message) || done('CRITICAL', "Couldn't get message $message from POP server $pop_server");
	foreach my $line ( @{ $lines } ) {
		#print $line;
		if ( $line =~ /^Subject:\s+(.*)$/o ) {
			$received_subject = $1;
			last;
		}
	}
	$pop->delete($message) || done('CRITICAL', "Couldn't delete message $message from POP server $pop_server");
}
$pop->quit() || done('CRITICAL', "Couldn't quit from POP server $pop_server");

#print "Subject:  $subject\n";
#print "Received: $received_subject\n";

if (not defined $received_subject) {
	$state = "WARNING";
	$answer = "No subject line received";
} elsif ($subject eq $received_subject) {
	$state = "OK";
	$answer = "Sent and received message correctly";
} else {
	$state = "WARNING";
	$answer = "Subject lines did not match wrong message received";
}

done($state, $answer);

sub done 
{
	my $state = shift;
	my $answer = shift;
	print ("$state: $answer");
	exit $ERRORS{$state};
}

sub usage {
	print "\nMissing arguments!\n";
	print "\n";
	print "check_email -H <HOSTNAME> -u <USERNAME> -p <PASSWORD> \n";
	print "Copyright (C) 2003 andrew fresh\n";
	print "\n\n";
	support();
	exit $ERRORS{"UNKNOWN"};
}

sub print_help {
	print "check_email plugin for Nagios monitors operational \n";
  	print "status of email flow on the target host.\n";
	print "It sends an e-mail to a test user, and then checks \n";
	print "a POP account. Failing at any point during if there is \n";
	print "a problem. It gives a WARNING if the mail is not received \n";
	print "in time, and gives a CRITICAL if it cannot connect to any \n";
	print "services. Do not use an account that you want to receive \n";
	print "mail from. This program will delete ALL mail in the mailbox \n";
	print "that you specify.";
	print "\n";
	print "\nUsage:\n";
	print "   -H (--hostname)   Hostname to query - (required)\n";
	print "   -u (--username)   Username whose mail to check - (required)\n";
	print "   -p (--password)   Password for user - (required)\n";
	print "   -P (--popserver)  Server to check mail on, defaults to --hostname\n";
	print "   -S (--smtpserver) Server to send mail to, defaults to --hostname\n";
	print "   -t (--to)         Address to send mail to, defaults to --username\@--hostname\n";
	print "   -f (--from)       Address to send mail from, defaults to Nagios <>\n";
	print "   -w (--wait)       Time (in seconds) to wait between sending the mail and checking for it, defaults to 1 second. \n";
	print_revision($PROGNAME, '$Revision: 1.3 $');
	
}