#!/usr/bin/perl
# Copyright (c) 2003 by Matthias Schmidt <schmidtm at mathematik.uni-marburg.de>
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
# 
#    - Redistributions of source code must retain the above copyright
#      notice, this list of conditions and the following disclaimer.
#    - Redistributions in binary form must reproduce the above
#      copyright notice, this list of conditions and the following
#      disclaimer in the documentation and/or other materials provided
#      with the distribution.
# 
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
# FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
# COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
# BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
# LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
# CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
# ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
# POSSIBILITY OF SUCH DAMAGE.
#
# $Id: spam.pl,v 1.3 2003/10/09 09:12:05 ms Exp $

###############################################################################
# Add the following line to your crontab. This will send a spam report 5 min
# after 6am every day
# 5 6 * * * /app/home/user/spam.pl

# Path to procmail.log (LOGFILE in .procmailrc)
$procmail_log	= "$ENV{'HOME'}/mail/log/procmail.log";

# Basename of your spam folder (eg. mine is /home/user/mail/spam)
$spam_folder	= "spam";

# Send spam report to local SMTP
$rcpt		= "$ENV{'USER'}";
# OR send it via sendmail to an external address
#$rcpt		= 'me@isp.com';

# Path to error log file
$error_log	= "$ENV{'HOME'}/spam.pl.error";
# mktemp(1) is not available on all systems, so we have to use this crappy
# alternative
$temp_mail	= "$ENV{'HOME'}/.temp-spam";
###############################################################################

$datum		= `date +%d.%m.%Y`; chomp($datum);
$zeit		= `date +%H:%M:%S`; chomp($zeit);
$normal_counter = 0;
$spam_mails	= 0;

sub parse_log;
sub write_error;
sub check_status;
sub generate_report;

##
# Parse procmail.log for new mails
##
sub 
parse_log
{
	check_status($procmail_log);

	open (fd, "<$procmail_log")
		or die write_error("Cannot open $procmail_log...\n");

	while (<fd>) {
		if (/From/) {
			$pos = index($_, '  ', 6);
			$temp = substr($_, 5, $pos - 5); 
			$from[$spam_mails] = $temp;
			$normal_counter++;
		}
		if (/Subject:/) {
			$temp = substr($_, index($_, ":")+2);
			$subject[$spam_mails] = $temp;
		}
		if ((/Folder: $spam_folder/) || (/Folder: \/dev\/null/)) {
			chomp($from[$spam_mails]);
			chomp($subject[$spam_mails]);
			$from2[$spam_mails] = "From\t: $from[$spam_mails]\nSubject\t: $subject[$spam_mails]";
			$spam_mails++;
		}
	}

	close (fd);

}

##
# Generate a little spam report
##
sub
generate_report
{
	open (fd, ">$temp_mail") or die write_error("Cannot open $temp_mail...\n");
	
	print fd "Report generated at $datum : $zeit\n\n";
	print fd "-----------------------------------------------------------------\n";
	print fd "Total number of received mails\t: $normal_counter\n";
	print fd "Total number of spam mail\t: $spam_mails\n";
	print fd "-----------------------------------------------------------------\n\n";
	print fd "Information about the new mails:\n\n";

	for ($h = 0; $h < $spam_mails; $h++) {
		print fd "$from2[$h]\n\n";
	}
	print fd "-----------------------------------------------------------------\n\n";

	close(fd);
}

##
# Log all errors
##
sub
write_error
{
	my $msg = $_[0];

	open (fd, ">>$error_log") or die "Cannot open $error_log...\n";
	print fd "$datum - $zeit : $msg";
	close (fd);
	
}

##
# Check stat(2) for a file
##
sub
check_status
{
	my $file = $_[0];
	
	if (!(-e $file)) {
		write_error("$file does not exists.\n");
		exit 1;
	}

	if (!(-r $file)) {
		write_error("Cannot read $file.\n");
		exit 1;
	}

	if (!(-o $file)) {
		write_error("I am not the owner of $file.\n");
		exit 1;
	}

	if (-l $file) {
		write_error("$file is a symbolic link.\n");
		exit 1
	}

	if (-z $file) {
		write_error("$file is empty.\n");
		exit 1;
	}
}

# Is temp_mail available on startup?
if (-e $temp_mail) {
	write_error("Removing $temp_mail ...\n");
	unlink $temp_mail or write_error("Cannot unlink $temp_mail...\n");
}

parse_log();

# No new mails
if ($spam_mails == 0) {
	write_error("No new spam mail -> quit.\n");
	exit 1;
}

generate_report();

system("mail -s \"-- $spam_mails new spam emails\" $rcpt < $temp_mail");

unlink $temp_mail or write_error("Cannot delete $temp_mail...\n");
# Update via mailstat
system("mailstat $procmail_log > /dev/null");