#!/usr/bin/perl -w
use strict;
use warnings;
use Mail::Sendmail;

@ARGV == 1 or die "usage: $0 watchfile";
my $watchfile = $ARGV[0];
print "watching $watchfile.\n";

my $pid = fork();
unless ( $pid ) {
    my $access_time = (stat($watchfile))[8];
    my $modify_time = (stat($watchfile))[9];
    while( sleep 5 ) {
	unless( $access_time == (stat($watchfile))[8] ) {
	    print "ACCESS CHANGED!!\n";
	    tripwire( $watchfile, "accessed" );
	    $access_time = (stat($watchfile))[8];
	}
	unless( $modify_time == (stat($watchfile))[9] ) {
	    print "MODIFY CHANGED!!\n";
	    tripwire( $watchfile, "modified" );
	    $modify_time = (stat($watchfile))[9];
	}
    }   
}

sub tripwire {
    my $file = shift || "unknown";
    my $what = shift || "unknown";
    my %mail = ( To      => 'pariss@efn.org',
		 From    => 'Aighearach@makeyourbanner.com',
		 Subject => 'SECURITY VIOLATION!!!',
		 Message => "SECURITY VIOLATION!!! $file $what\n".`who`
		 );
    sendmail(%mail);
    `wall 'what the hell are you doing\? --AUTOMATED (report generated)'`;   
}