logout.php

<?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/>.

/**
 * Logs the user out. It is a copy of the Moodle logout page with sesskey functionality removed
 *
 * @package    auth_samlidp
 * @copyright  2017 Enovation Solutions (http://enovation.ie)
 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 */

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

$PAGE->set_url('/auth/samlidp/logout.php');
$PAGE->set_context(context_system::instance());

$login   = optional_param('loginpage', 0, PARAM_BOOL);

// can be overridden by auth plugins
if ($login) {
    $redirect = get_login_url();
} else {
    $redirect = $CFG->wwwroot.'/';
}

if (!isloggedin()) {
    // no confirmation, user has already logged out
    require_logout();
    redirect($redirect);
}

$authsequence = get_enabled_auth_plugins(); // auths, in sequence
foreach ($authsequence as $authname) {
    $authplugin = get_auth_plugin($authname);
    $authplugin->logoutpage_hook();
}

require_logout();

redirect($redirect);