use strict;
use warnings;
use CGI ();
use URI ();

my $subject = subject() || '';

print "Subject: $subject\n";

sub subject {
    my $cgi         = CGI->new;
    my $referrerUrl = $cgi->param('referrerUrl');
    my $uri         = URI->new($referrerUrl);
    my $path        = $uri->path;
    my %param       = $uri->query_form;
    my $value       = $param{q} || return;

    return $value =~ /log/          ? 'logging'
         : $value =~ /mailq/        ? 'mailq'
         : $value =~ /loops.+?back/ ? 'loopsback'
         : $value =~ /port/         ? 'changeport'
         : $value =~ /white.+?list/ ? 'whitelist'
         :                            ''
         ;
}