
<?php

require_once('/path/to/your/config/file/config.php');

global $SESSION;

if (isset($_GET['url'])) {
    $SESSION->wantsurl = $_GET['url'];
} else {
    $SESSION->wantsurl = '/';
}

$authplugin = get_auth_plugin('drupalservices');
$authplugin->loginpage_hook();

?>