Drupal script to login without password

drupal-login.php

<?php

/**
 * Script to login as any user in Drupal without password.
 * Put the script in root directory and use  any of these formats.
 * '/script.php?user=admin'
 * '/script.php?uid=1'
 * '/script.php'
 * 
 * NEVER EVER EVER commit this to publicly accessible instance.
 * 
 * Copyright (c) 2016 Anish A <aneesh.nl@gmail.com>,
 * Anoop John <anoop.john@zyxware.com>.
 * 
 * Permission is hereby granted, free of charge, to any person
 * obtaining a copy of this software and associated documentation
 * files (the "Software"), to deal in the Software without restriction,
 * including without limitation the rights to use, copy, modify, merge,
 * publish, distribute, sublicense, and/or sell copies of the Software,
 * and to permit persons to whom the Software is furnished to do so,
 * subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
 * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR
 * THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 * 
 */

// Accepts both uid and user arguments with uid 1 as default.
$uid = isset($_GET['uid'])?$_GET['uid']:1;
$user_name = isset($_GET['user'])?$_GET['user']:NULL;

define('DRUPAL_ROOT', getcwd());

require_once DRUPAL_ROOT . '/includes/bootstrap.inc';
drupal_bootstrap(DRUPAL_BOOTSTRAP_FULL);

global $user;
$user = user_load_by_name($user_name);
if(FALSE === $user) {
  $user = user_load($uid);
}

drupal_session_regenerate();
drupal_goto('user');