<?php
// This file is part of Moodle - http://moodle.org/
//
// Moodle is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// Moodle is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.

/**
 * Authentication Plugin: PAM Authentication
 *
 * PAM (Pluggable Authentication Modules) for Moodle
 *
 * Description:
 * Authentication by using the PHP4 PAM module:
 * http://www.math.ohio-state.edu/~ccunning/pam_auth/
 *
 * Version 0.3  2006/09/07 by Jonathan Harker (plugin class)
 * Version 0.2: 2004/09/01 by Martin V�geli (stable version)
 * Version 0.1: 2004/08/30 by Martin V�geli (first draft)
 *
 * Contact: martinvoegeli@gmx.ch
 * Website 1: http://elearning.zhwin.ch/
 * Website 2: http://birdy1976.com/
 *
 * @package auth_pam
 * @author Martin Dougiamas
 * @license http://www.gnu.org/copyleft/gpl.html GNU Public License
 */

defined('MOODLE_INTERNAL') || die();

require_once($CFG->libdir.'/authlib.php');

/**
 * PAM authentication plugin.
 */
class auth_plugin_pam extends auth_plugin_base {

    /**
     * Store error messages from pam authentication attempts.
     */
    var $lasterror;

    /**
     * Constructor.
     */
    public function __construct() {
        $this->authtype = 'pam';
        $this->config = get_config('auth_pam');
        $this->errormessage = '';
    }

    /**
     * Old syntax of class constructor. Deprecated in PHP7.
     *
     * @deprecated since Moodle 3.1
     */
    public function auth_plugin_pam() {
        debugging('Use of class name as constructor is deprecated', DEBUG_DEVELOPER);
        self::__construct();
    }

    /**
     * Returns true if the username and password work and false if they are
     * wrong or don't exist.
     *
     * @param string $username The username
     * @param string $password The password
     * @return bool Authentication success or failure.
     */
    function user_login ($username, $password) {
        // variable to store possible errors during authentication
        $errormessage = str_repeat(' ', 2048);

        // just for testing and debugging
        // error_reporting(E_ALL);

        // call_time_pass_reference of errormessage is deprecated - throws warnings in multiauth
        //if (pam_auth($username, $password, &$errormessage)) {
        if (pam_auth($username, $password)) {
            return true;
        }
        else {
            $this->lasterror = $errormessage;
            return false;
        }
    }

    function prevent_local_passwords() {
        return true;
    }

    /**
     * Returns true if this authentication plugin is 'internal'.
     *
     * @return bool
     */
    function is_internal() {
        return false;
    }

    /**
     * Returns true if this authentication plugin can change the user's
     * password.
     *
     * @return bool
     */
    function can_change_password() {
        return false;
    }

}


