moodle/course/jumpto.php

<?php  // $Id$

/*
 *  Jumps to a given relative or Moodle absolute URL.
 *  Mostly used for accessibility.
 *
 */

    require('../config.php');

    $jump = optional_param('jump', '', PARAM_RAW);

    if (!confirm_sesskey()) {
        print_error('confirmsesskeybad');
    }

    if (strpos($jump, $CFG->wwwroot) === 0) {            // Anything on this site
        redirect(urldecode($jump));
    } else if (preg_match('/^[a-z]+\.php\?/', $jump)) { 
        redirect(urldecode($jump));
    }

    redirect($_SERVER['HTTP_REFERER']);   // Return to sender, just in case

?>