nextcloud/lib/base.php

<?php
/**
 * ownCloud
 *
 * @author Frank Karlitschek
 * @copyright 2012 Frank Karlitschek frank@owncloud.org
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU AFFERO GENERAL PUBLIC LICENSE
 * License as published by the Free Software Foundation; either
 * version 3 of the License, or any later version.
 *
 * This library 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 AFFERO GENERAL PUBLIC LICENSE for more details.
 *
 * You should have received a copy of the GNU Affero General Public
 * License along with this library.  If not, see <http://www.gnu.org/licenses/>.
 *
 */

/**
 * Class that is a namespace for all global OC variables
 * No, we can not put this class in its own file because it is used by
 * OC_autoload!
 */
class OC{
	/**
	 * Assoziative array for autoloading. classname => filename
	 */
	public static $CLASSPATH = array();
	/**
	 * The installation path for owncloud on the server (e.g. /srv/http/owncloud)
	 */
	public static $SERVERROOT = '';
	/**
	 * the current request path relative to the owncloud root (e.g. files/index.php)
	 */
	private static $SUBURI = '';
	/**
	 * the owncloud root path for http requests (e.g. owncloud/)
	 */
	public static $WEBROOT = '';
	/**
	 * The installation path of the 3rdparty folder on the server (e.g. /srv/http/owncloud/3rdparty)
	 */
	public static $THIRDPARTYROOT = '';
	/**
	 * the root path of the 3rdparty folder for http requests (e.g. owncloud/3rdparty)
	 */
	public static $THIRDPARTYWEBROOT = '';
	/**
	 * The installation path array of the apps folder on the server (e.g. /srv/http/owncloud) 'path' and
	 * web path in 'url'
	 */
	public static $APPSROOTS = array();
	/*
	 * requested app
	 */
	public static $REQUESTEDAPP = '';
	/*
	 * requested file of app
	 */
	public static $REQUESTEDFILE = '';
	/**
	 * check if owncloud runs in cli mode
	 */
	public static $CLI = false;
	/**
	 * SPL autoload
	 */
	public static function autoload($className) {
		if(array_key_exists($className, OC::$CLASSPATH)) {
			$path = OC::$CLASSPATH[$className];
			/** @TODO: Remove this when necessary
			 Remove "apps/" from inclusion path for smooth migration to mutli app dir
			*/
			if (strpos($path, 'apps/')===0) {
				OC_Log::write('core', 'include path for class "'.$className.'" starts with "apps/"', OC_Log::DEBUG);
				$path = str_replace('apps/', '', $path);
			}
		}
		elseif(strpos($className, 'OC_')===0) {
			$path = strtolower(str_replace('_', '/', substr($className, 3)) . '.php');
		}
		elseif(strpos($className, 'OCP\\')===0) {
			$path = 'public/'.strtolower(str_replace('\\', '/', substr($className, 3)) . '.php');
		}
		elseif(strpos($className, 'OCA\\')===0) {
			$path = 'apps/'.strtolower(str_replace('\\', '/', substr($className, 3)) . '.php');
		}
		elseif(strpos($className, 'Sabre_')===0) {
			$path =  str_replace('_', '/', $className) . '.php';
		}
		elseif(strpos($className, 'Test_')===0) {
			$path =  'tests/lib/'.strtolower(str_replace('_', '/', substr($className, 5)) . '.php');
		}else{
			return false;
		}

		if($fullPath = stream_resolve_include_path($path)) {
			require_once $fullPath;
		}
		return false;
	}

	public static function initPaths() {
		// calculate the root directories
		OC::$SERVERROOT=str_replace("\\", '/', substr(__DIR__, 0, -4));
		OC::$SUBURI= str_replace("\\", "/", substr(realpath($_SERVER["SCRIPT_FILENAME"]), strlen(OC::$SERVERROOT)));
		$scriptName=$_SERVER["SCRIPT_NAME"];
		if(substr($scriptName, -1)=='/') {
			$scriptName.='index.php';
			//make sure suburi follows the same rules as scriptName
			if(substr(OC::$SUBURI, -9)!='index.php') {
				if(substr(OC::$SUBURI, -1)!='/') {
					OC::$SUBURI=OC::$SUBURI.'/';
				}
				OC::$SUBURI=OC::$SUBURI.'index.php';
			}
		}

		OC::$WEBROOT=substr($scriptName, 0, strlen($scriptName)-strlen(OC::$SUBURI));

		if(OC::$WEBROOT!='' and OC::$WEBROOT[0]!=='/') {
			OC::$WEBROOT='/'.OC::$WEBROOT;
		}

		// ensure we can find OC_Config
		set_include_path(
			OC::$SERVERROOT.'/lib'.PATH_SEPARATOR.
			get_include_path()
		);

		// search the 3rdparty folder
		if(OC_Config::getValue('3rdpartyroot', '')<>'' and OC_Config::getValue('3rdpartyurl', '')<>'') {
			OC::$THIRDPARTYROOT=OC_Config::getValue('3rdpartyroot', '');
			OC::$THIRDPARTYWEBROOT=OC_Config::getValue('3rdpartyurl', '');
		}elseif(file_exists(OC::$SERVERROOT.'/3rdparty')) {
			OC::$THIRDPARTYROOT=OC::$SERVERROOT;
			OC::$THIRDPARTYWEBROOT=OC::$WEBROOT;
		}elseif(file_exists(OC::$SERVERROOT.'/../3rdparty')) {
			OC::$THIRDPARTYWEBROOT=rtrim(dirname(OC::$WEBROOT), '/');
			OC::$THIRDPARTYROOT=rtrim(dirname(OC::$SERVERROOT), '/');
		}else{
			echo("3rdparty directory not found! Please put the ownCloud 3rdparty folder in the ownCloud folder or the folder above. You can also configure the location in the config.php file.");
			exit;
		}
		// search the apps folder
		$config_paths = OC_Config::getValue('apps_paths', array());
		if(! empty($config_paths)) {
			foreach($config_paths as $paths) {
				if( isset($paths['url']) && isset($paths['path'])) {
					$paths['url'] = rtrim($paths['url'], '/');
					$paths['path'] = rtrim($paths['path'], '/');
					OC::$APPSROOTS[] = $paths;
				}
			}
		}elseif(file_exists(OC::$SERVERROOT.'/apps')) {
			OC::$APPSROOTS[] = array('path'=> OC::$SERVERROOT.'/apps', 'url' => '/apps', 'writable' => true);
		}elseif(file_exists(OC::$SERVERROOT.'/../apps')) {
			OC::$APPSROOTS[] = array('path'=> rtrim(dirname(OC::$SERVERROOT), '/').'/apps', 'url' => '/apps', 'writable' => true);
		}

		if(empty(OC::$APPSROOTS)) {
			echo("apps directory not found! Please put the ownCloud apps folder in the ownCloud folder or the folder above. You can also configure the location in the config.php file.");
			exit;
		}
		$paths = array();
		foreach( OC::$APPSROOTS as $path)
			$paths[] = $path['path'];

		// set the right include path
		set_include_path(
			OC::$SERVERROOT.'/lib'.PATH_SEPARATOR.
			OC::$SERVERROOT.'/config'.PATH_SEPARATOR.
			OC::$THIRDPARTYROOT.'/3rdparty'.PATH_SEPARATOR.
			implode($paths,PATH_SEPARATOR).PATH_SEPARATOR.
			get_include_path().PATH_SEPARATOR.
			OC::$SERVERROOT
		);
	}

	public static function checkInstalled() {
		// Redirect to installer if not installed
		if (!OC_Config::getValue('installed', false) && OC::$SUBURI != '/index.php') {
			if(!OC::$CLI) {
				$url = 'http://'.$_SERVER['SERVER_NAME'].OC::$WEBROOT.'/index.php';
				header("Location: $url");
			}
			exit();
		}
	}

	public static function checkSSL() {
		// redirect to https site if configured
		if( OC_Config::getValue( "forcessl", false )) {
			header('Strict-Transport-Security: max-age=31536000');
			ini_set("session.cookie_secure", "on");
			if(OC_Request::serverProtocol()<>'https' and !OC::$CLI) {
				$url = "https://". OC_Request::serverHost() . $_SERVER['REQUEST_URI'];
				header("Location: $url");
				exit();
			}
		}
	}

	public static function checkUpgrade() {
		if(OC_Config::getValue('installed', false)) {
			$installedVersion=OC_Config::getValue('version', '0.0.0');
			$currentVersion=implode('.', OC_Util::getVersion());
			if (version_compare($currentVersion, $installedVersion, '>')) {
				OC_Log::write('core', 'starting upgrade from '.$installedVersion.' to '.$currentVersion, OC_Log::DEBUG);
				$result=OC_DB::updateDbFromStructure(OC::$SERVERROOT.'/db_structure.xml');
				if(!$result) {
					echo 'Error while upgrading the database';
					die();
				}
				if(file_exists(OC::$SERVERROOT."/config/config.php") and !is_writable(OC::$SERVERROOT."/config/config.php")) {
					$tmpl = new OC_Template( '', 'error', 'guest' );
					$tmpl->assign('errors', array(1=>array('error'=>"Can't write into config directory 'config'",'hint'=>"You can usually fix this by giving the webserver user write access to the config directory in owncloud")));
					$tmpl->printPage();
					exit;
				}
				$minimizerCSS = new OC_Minimizer_CSS();
				$minimizerCSS->clearCache();
				$minimizerJS = new OC_Minimizer_JS();
				$minimizerJS->clearCache();
				OC_Config::setValue('version', implode('.', OC_Util::getVersion()));
				OC_App::checkAppsRequirements();
				// load all apps to also upgrade enabled apps
				OC_App::loadApps();
			}
		}
	}

	public static function initTemplateEngine() {
		// Add the stuff we need always
		OC_Util::addScript( "jquery-1.7.2.min" );
		OC_Util::addScript( "jquery-ui-1.8.16.custom.min" );
		OC_Util::addScript( "jquery-showpassword" );
		OC_Util::addScript( "jquery.infieldlabel.min" );
		OC_Util::addScript( "jquery-tipsy" );
		OC_Util::addScript( "oc-dialogs" );
		OC_Util::addScript( "js" );
		// request protection token MUST be defined after the jquery library but before any $('document').ready()
		OC_Util::addScript( "requesttoken" );
		OC_Util::addScript( "eventsource" );
		OC_Util::addScript( "config" );
		//OC_Util::addScript( "multiselect" );
		OC_Util::addScript('search', 'result');

		if( OC_Config::getValue( 'installed', false )) {
			if( OC_Appconfig::getValue( 'core', 'backgroundjobs_mode', 'ajax' ) == 'ajax' ) {
				OC_Util::addScript( 'backgroundjobs' );
			}
		}

		OC_Util::addStyle( "styles" );
		OC_Util::addStyle( "multiselect" );
		OC_Util::addStyle( "jquery-ui-1.8.16.custom" );
		OC_Util::addStyle( "jquery-tipsy" );
	}

	public static function initSession() {
		ini_set('session.cookie_httponly', '1;');
		session_start();
	}

	public static function init() {
		// register autoloader
		spl_autoload_register(array('OC','autoload'));
		setlocale(LC_ALL, 'en_US.UTF-8');

		// set some stuff
		//ob_start();
		error_reporting(E_ALL | E_STRICT);
		if (defined('DEBUG') && DEBUG) {
			ini_set('display_errors', 1);
		}
		self::$CLI=(php_sapi_name() == 'cli');

		date_default_timezone_set('UTC');
		ini_set('arg_separator.output', '&amp;');

		// try to switch magic quotes off.
		if(function_exists('set_magic_quotes_runtime')) {
			@set_magic_quotes_runtime(false);
		}

		//try to configure php to enable big file uploads.
		//this doesn´t work always depending on the webserver and php configuration.
		//Let´s try to overwrite some defaults anyways

		//try to set the maximum execution time to 60min
		@set_time_limit(3600);
		@ini_set('max_execution_time', 3600);
		@ini_set('max_input_time', 3600);

		//try to set the maximum filesize to 10G
		@ini_set('upload_max_filesize', '10G');
		@ini_set('post_max_size', '10G');
		@ini_set('file_uploads', '50');

		//try to set the session lifetime to 60min
		@ini_set('gc_maxlifetime', '3600');


		//set http auth headers for apache+php-cgi work around
		if (isset($_SERVER['HTTP_AUTHORIZATION']) && preg_match('/Basic\s+(.*)$/i', $_SERVER['HTTP_AUTHORIZATION'], $matches)) {
			list($name, $password) = explode(':', base64_decode($matches[1]), 2);
			$_SERVER['PHP_AUTH_USER'] = strip_tags($name);
			$_SERVER['PHP_AUTH_PW'] = strip_tags($password);
		}

		//set http auth headers for apache+php-cgi work around if variable gets renamed by apache
		if (isset($_SERVER['REDIRECT_HTTP_AUTHORIZATION']) && preg_match('/Basic\s+(.*)$/i', $_SERVER['REDIRECT_HTTP_AUTHORIZATION'], $matches)) {
			list($name, $password) = explode(':', base64_decode($matches[1]), 2);
			$_SERVER['PHP_AUTH_USER'] = strip_tags($name);
			$_SERVER['PHP_AUTH_PW'] = strip_tags($password);
		}

		self::initPaths();

		// set debug mode if an xdebug session is active
		if (!defined('DEBUG') || !DEBUG) {
			if(isset($_COOKIE['XDEBUG_SESSION'])) {
				define('DEBUG', true);
			}
		}

		// register the stream wrappers
		require_once 'streamwrappers.php';
		stream_wrapper_register("fakedir", "OC_FakeDirStream");
		stream_wrapper_register('static', 'OC_StaticStreamWrapper');
		stream_wrapper_register('close', 'OC_CloseStreamWrapper');

		self::checkInstalled();
		self::checkSSL();
		self::initSession();
		self::initTemplateEngine();
		self::checkUpgrade();

		$errors=OC_Util::checkServer();
		if(count($errors)>0) {
			OC_Template::printGuestPage('', 'error', array('errors' => $errors));
			exit;
		}

		// User and Groups
		if( !OC_Config::getValue( "installed", false )) {
			$_SESSION['user_id'] = '';
		}

		OC_User::useBackend(new OC_User_Database());
		OC_Group::useBackend(new OC_Group_Database());

		if(isset($_SERVER['PHP_AUTH_USER']) && isset($_SESSION['user_id']) && $_SERVER['PHP_AUTH_USER'] != $_SESSION['user_id']) {
			OC_User::logout();
		}

		// Load Apps
		// This includes plugins for users and filesystems as well
		global $RUNTIME_NOAPPS;
		global $RUNTIME_APPTYPES;
		if(!$RUNTIME_NOAPPS ) {
			if($RUNTIME_APPTYPES) {
				OC_App::loadApps($RUNTIME_APPTYPES);
			}else{
				OC_App::loadApps();
			}
		}

		//setup extra user backends
		OC_User::setupBackends();

		// register cache cleanup jobs
		OC_BackgroundJob_RegularTask::register('OC_Cache_FileGlobal', 'gc');
		OC_Hook::connect('OC_User', 'post_login', 'OC_Cache_File', 'loginListener');

		// Check for blacklisted files
		OC_Hook::connect('OC_Filesystem', 'write', 'OC_Filesystem', 'isBlacklisted');
		OC_Hook::connect('OC_Filesystem', 'rename', 'OC_Filesystem', 'isBlacklisted');

		//make sure temporary files are cleaned up
		register_shutdown_function(array('OC_Helper','cleanTmp'));

		//parse the given parameters
		self::$REQUESTEDAPP = (isset($_GET['app']) && trim($_GET['app']) != '' && !is_null($_GET['app'])?str_replace(array('\0', '/', '\\', '..'), '', strip_tags($_GET['app'])):OC_Config::getValue('defaultapp', 'files'));
		if(substr_count(self::$REQUESTEDAPP, '?') != 0) {
			$app = substr(self::$REQUESTEDAPP, 0, strpos(self::$REQUESTEDAPP, '?'));
			$param = substr($_GET['app'], strpos($_GET['app'], '?') + 1);
			parse_str($param, $get);
			$_GET = array_merge($_GET, $get);
			self::$REQUESTEDAPP = $app;
			$_GET['app'] = $app;
		}
		self::$REQUESTEDFILE = (isset($_GET['getfile'])?$_GET['getfile']:null);
		if(substr_count(self::$REQUESTEDFILE, '?') != 0) {
			$file = substr(self::$REQUESTEDFILE, 0, strpos(self::$REQUESTEDFILE, '?'));
			$param = substr(self::$REQUESTEDFILE, strpos(self::$REQUESTEDFILE, '?') + 1);
			parse_str($param, $get);
			$_GET = array_merge($_GET, $get);
			self::$REQUESTEDFILE = $file;
			$_GET['getfile'] = $file;
		}
		if(!is_null(self::$REQUESTEDFILE)) {
			$subdir = OC_App::getAppPath(OC::$REQUESTEDAPP) . '/' . self::$REQUESTEDFILE;
			$parent = OC_App::getAppPath(OC::$REQUESTEDAPP);
			if(!OC_Helper::issubdirectory($subdir, $parent)) {
				self::$REQUESTEDFILE = null;
				header('HTTP/1.0 404 Not Found');
				exit;
			}
		}
	}

	/**
	 * @brief Handle the request
	 */
	public static function handleRequest() {
		if (!OC_Config::getValue('installed', false)) {
			// Check for autosetup:
			$autosetup_file = OC::$SERVERROOT."/config/autoconfig.php";
			if( file_exists( $autosetup_file )) {
				OC_Log::write('core', 'Autoconfig file found, setting up owncloud...', OC_Log::INFO);
				include $autosetup_file;
				$_POST['install'] = 'true';
				$_POST = array_merge ($_POST, $AUTOCONFIG);
				unlink($autosetup_file);
			}
			OC_Util::addScript('setup');
			require_once 'setup.php';
			exit();
		}
		// Handle WebDAV
		if($_SERVER['REQUEST_METHOD']=='PROPFIND') {
			header('location: '.OC_Helper::linkToRemote('webdav'));
			return;
		}
		// Handle app css files
		if(substr(OC::$REQUESTEDFILE, -3) == 'css') {
			self::loadCSSFile();
			return;
		}
		// Someone is logged in :
		if(OC_User::isLoggedIn()) {
			OC_App::loadApps();
			OC_User::setupBackends();
			if(isset($_GET["logout"]) and ($_GET["logout"])) {
				OC_Preferences::deleteKey(OC_User::getUser(), 'login_token', $_COOKIE['oc_token']);
				OC_User::logout();
				header("Location: ".OC::$WEBROOT.'/');
			}else{
				$app = OC::$REQUESTEDAPP;
				$file = OC::$REQUESTEDFILE;
				if(is_null($file)) {
					$file = 'index.php';
				}
				$file_ext = substr($file, -3);
				if ($file_ext != 'php'|| !self::loadAppScriptFile($app, $file)) {
					header('HTTP/1.0 404 Not Found');
				}
			}
			return;
		}
		// Not handled and not logged in
		self::handleLogin();
	}

	protected static function loadAppScriptFile($app, $file) {
		$app_path = OC_App::getAppPath($app);
		$file = $app_path . '/' . $file;
		unset($app, $app_path);
		if (file_exists($file)) {
			require_once $file;
			return true;
		}
		return false;
	}

	protected static function loadCSSFile() {
		$app = OC::$REQUESTEDAPP;
		$file = OC::$REQUESTEDFILE;
		$app_path = OC_App::getAppPath($app);
		if (file_exists($app_path . '/' . $file)) {
			$app_web_path = OC_App::getAppWebPath($app);
			$filepath = $app_web_path . '/' . $file;
			$minimizer = new OC_Minimizer_CSS();
			$info = array($app_path, $app_web_path, $file);
			$minimizer->output(array($info), $filepath);
		}
	}

	protected static function handleLogin() {
		OC_App::loadApps(array('prelogin'));
		$error = false;
		// remember was checked after last login
		if (OC::tryRememberLogin()) {
			// nothing more to do

		// Someone wants to log in :
		} elseif (OC::tryFormLogin()) {
			$error = true;

		// The user is already authenticated using Apaches AuthType Basic... very usable in combination with LDAP
		} elseif (OC::tryBasicAuthLogin()) {
			$error = true;
		}
		OC_Util::displayLoginPage($error);
	}

	protected static function cleanupLoginTokens($user) {
		$cutoff = time() - OC_Config::getValue('remember_login_cookie_lifetime', 60*60*24*15);
		$tokens = OC_Preferences::getKeys($user, 'login_token');
		foreach($tokens as $token) {
			$time = OC_Preferences::getValue($user, 'login_token', $token);
			if ($time < $cutoff) {
				OC_Preferences::deleteKey($user, 'login_token', $token);
			}
		}
	}

	protected static function tryRememberLogin() {
		if(!isset($_COOKIE["oc_remember_login"])
			|| !isset($_COOKIE["oc_token"])
			|| !isset($_COOKIE["oc_username"])
			|| !$_COOKIE["oc_remember_login"])
		{
			return false;
		}
		OC_App::loadApps(array('authentication'));
		if(defined("DEBUG") && DEBUG) {
			OC_Log::write('core', 'Trying to login from cookie', OC_Log::DEBUG);
		}
		// confirm credentials in cookie
		if(isset($_COOKIE['oc_token']) && OC_User::userExists($_COOKIE['oc_username'])) {
			// delete outdated cookies
			self::cleanupLoginTokens($_COOKIE['oc_username']);
			// get stored tokens
			$tokens = OC_Preferences::getKeys($_COOKIE['oc_username'], 'login_token');
			// test cookies token against stored tokens
			if (in_array($_COOKIE['oc_token'], $tokens, true)) {
				// replace successfully used token with a new one
				OC_Preferences::deleteKey($_COOKIE['oc_username'], 'login_token', $_COOKIE['oc_token']);
				$token = md5($_COOKIE['oc_username'].OC_Util::generate_random_bytes(10).$_COOKIE['oc_token']);
				OC_Preferences::setValue($_COOKIE['oc_username'], 'login_token', $token, time());
				OC_User::setMagicInCookie($_COOKIE['oc_username'], $token);
				// login
				OC_User::setUserId($_COOKIE['oc_username']);
				OC_Util::redirectToDefaultPage();
				// doesn't return
			}
			// if you reach this point you have changed your password 
			// or you are an attacker
			// we can not delete tokens here because users may reach 
			// this point multiple times after a password change
			OC_Log::write('core', 'Authentication cookie rejected for user '.$_COOKIE['oc_username'], OC_Log::WARN);
		}
		OC_User::unsetMagicInCookie();
		return true;
	}

	protected static function tryFormLogin() {
		if(!isset($_POST["user"]) || !isset($_POST['password'])) {
			return false;
		}

		OC_App::loadApps();

		//setup extra user backends
		OC_User::setupBackends();

		if(OC_User::login($_POST["user"], $_POST["password"])) {
			self::cleanupLoginTokens($_POST['user']);
			if(!empty($_POST["remember_login"])) {
				if(defined("DEBUG") && DEBUG) {
					OC_Log::write('core', 'Setting remember login to cookie', OC_Log::DEBUG);
				}
				$token = md5($_POST["user"].OC_Util::generate_random_bytes(10).$_POST['password']);
				OC_Preferences::setValue($_POST['user'], 'login_token', $token, time());
				OC_User::setMagicInCookie($_POST["user"], $token);
			}
			else {
				OC_User::unsetMagicInCookie();
			}
			header( 'Location: '.$_SERVER['REQUEST_URI'] );
			exit();
		}
		return true;
	}

	protected static function tryBasicAuthLogin() {
		if (!isset($_SERVER["PHP_AUTH_USER"])
		 || !isset($_SERVER["PHP_AUTH_PW"])) {
			return false;
		}
		OC_App::loadApps(array('authentication'));
		if (OC_User::login($_SERVER["PHP_AUTH_USER"], $_SERVER["PHP_AUTH_PW"])) {
			//OC_Log::write('core',"Logged in with HTTP Authentication",OC_Log::DEBUG);
			OC_User::unsetMagicInCookie();
			$_REQUEST['redirect_url'] = (isset($_SERVER['REQUEST_URI'])?$_SERVER['REQUEST_URI']:'');
			OC_Util::redirectToDefaultPage();
		}
		return true;
	}

}

// define runtime variables - unless this already has been done
if( !isset( $RUNTIME_NOAPPS )) {
	$RUNTIME_NOAPPS = false;
}

if(!function_exists('get_temp_dir')) {
	function get_temp_dir() {
		if( $temp=ini_get('upload_tmp_dir') )        return $temp;
		if( $temp=getenv('TMP') )        return $temp;
		if( $temp=getenv('TEMP') )        return $temp;
		if( $temp=getenv('TMPDIR') )    return $temp;
		$temp=tempnam(__FILE__, '');
		if (file_exists($temp)) {
			unlink($temp);
			return dirname($temp);
		}
		if( $temp=sys_get_temp_dir())    return $temp;

		return null;
	}
}

OC::init();