lib/setup.php

   1 <?php
   2 /**
   3  * setup.php - Sets up sessions, connects to databases and so on
   4  *
   5  * Normally this is only called by the main config.php file
   6  * Normally this file does not need to be edited.
   7  * @author Martin Dougiamas
   8  * @version $Id$
   9  * @license http://www.gnu.org/copyleft/gpl.html GNU Public License
  10  * @package moodlecore
  11  */
  12
  13 ////// DOCUMENTATION IN PHPDOC FORMAT FOR MOODLE GLOBALS AND COMMON OBJECT TYPES /////////////
  14 /**
  15  * $USER is a global instance of a typical $user record.
  16  *
  17  * Items found in the user record:
  18  *  - $USER->emailstop - Does the user want email sent to them?
  19  *  - $USER->email - The user's email address.
  20  *  - $USER->id - The unique integer identified of this user in the 'user' table.
  21  *  - $USER->email - The user's email address.
  22  *  - $USER->firstname - The user's first name.
  23  *  - $USER->lastname - The user's last name.
  24  *  - $USER->username - The user's login username.
  25  *  - $USER->secret - The user's ?.
  26  *  - $USER->lang - The user's language choice.
  27  *
  28  * @global object(user) $USER
  29  */
  30 global $USER;
  31 /**
  32  * This global variable is read in from the 'config' table.
  33  *
  34  * Some typical settings in the $CFG global:
  35  *  - $CFG->wwwroot - Path to moodle index directory in url format.
  36  *  - $CFG->dataroot - Path to moodle index directory on server's filesystem.
  37  *  - $CFG->libdir  - Path to moodle's library folder on server's filesystem.
  38  *
  39  * @global object(cfg) $CFG
  40  */
  41 global $CFG;
  42 /**
  43  * Definition of session type
  44  * @global object(session) $SESSION
  45  */
  46 global $SESSION;
  47 /**
  48  * Definition of shared memory cache
  49  */
  50 global $MCACHE;
  51 /**
  52  * Definition of course type
  53  * @global object(course) $COURSE
  54  */
  55 global $COURSE;
  56 /**
  57  * Definition of db type
  58  * @global object(db) $db
  59  */
  60 global $db;
  61 /**
  62  * $THEME is a global that defines the site theme.
  63  *
  64  * Items found in the theme record:
  65  *  - $THEME->cellheading - Cell colors.
  66  *  - $THEME->cellheading2 - Alternate cell colors.
  67  *
  68  * @global object(theme) $THEME
  69  */
  70 global $THEME;
  71
  72 /**
  73  * HTTPSPAGEREQUIRED is a global to define if the page being displayed must run under HTTPS.
  74  *
  75  * It's primary goal is to allow 100% HTTPS pages when $CFG->loginhttps is enabled. Default to false.
  76  * It's enabled only by the httpsrequired() function and used in some pages to update some URLs
  77 */
  78 global $HTTPSPAGEREQUIRED;
  79
  80
  81 /// First try to detect some attacks on older buggy PHP versions
  82     if (isset($_REQUEST['GLOBALS']) || isset($_COOKIE['GLOBALS']) || isset($_FILES['GLOBALS'])) {
  83         die('Fatal: Illegal GLOBALS overwrite attempt detected!');
  84     }
  85
  86
  87     if (!isset($CFG->wwwroot)) {
  88         trigger_error('Fatal: $CFG->wwwroot is not configured! Exiting.');
  89         die;
  90     }
  91
  92 /// Set httpswwwroot default value (this variable will replace $CFG->wwwroot
  93 /// inside some URLs used in HTTPSPAGEREQUIRED pages.
  94     $CFG->httpswwwroot = $CFG->wwwroot;
  95
  96     $CFG->libdir   = $CFG->dirroot .'/lib';
  97
  98     require_once($CFG->libdir .'/setuplib.php');        // Functions that MUST be loaded first
  99
 100 /// Time to start counting
 101     init_performance_info();
 102
 103
 104 /// If there are any errors in the standard libraries we want to know!
 105     error_reporting(E_ALL);
 106
 107 /// Just say no to link prefetching (Moz prefetching, Google Web Accelerator, others)
 108 /// http://www.google.com/webmasters/faq.html#prefetchblock
 109     if (!empty($_SERVER['HTTP_X_moz']) && $_SERVER['HTTP_X_moz'] === 'prefetch'){
 110         header($_SERVER['SERVER_PROTOCOL'] . ' 404 Prefetch Forbidden');
 111         trigger_error('Prefetch request forbidden.');
 112         exit;
 113     }
 114
 115 /// Connect to the database using adodb
 116
 117 /// Some defines required BEFORE including AdoDB library
 118     define ('ADODB_ASSOC_CASE', 0); //Use lowercase fieldnames for ADODB_FETCH_ASSOC
 119                                     //(only meaningful for oci8po, it's the default
 120                                     //for other DB drivers so this won't affect them)
 121
 122     require_once($CFG->libdir .'/adodb/adodb.inc.php'); // Database access functions
 123
 124     $db = &ADONewConnection($CFG->dbtype);
 125
 126     // See MDL-6760 for why this is necessary. In Moodle 1.8, once we start using NULLs properly,
 127     // we probably want to change this value to ''.
 128     $db->null2null = 'A long random string that will never, ever match something we want to insert into the database, I hope. \'';
 129
 130     error_reporting(0);  // Hide errors
 131
 132     if (!isset($CFG->dbpersist) or !empty($CFG->dbpersist)) {    // Use persistent connection (default)
 133         $dbconnected = $db->PConnect($CFG->dbhost,$CFG->dbuser,$CFG->dbpass,$CFG->dbname);
 134     } else {                                                     // Use single connection
 135         $dbconnected = $db->Connect($CFG->dbhost,$CFG->dbuser,$CFG->dbpass,$CFG->dbname);
 136     }
 137     if (! $dbconnected) {
 138         // In the name of protocol correctness, monitoring and performance
 139         // profiling, set the appropriate error headers for machine comsumption
 140         if (isset($_SERVER['SERVER_PROTOCOL'])) {
 141             // Avoid it with cron.php. Note that we assume it's HTTP/1.x
 142             header($_SERVER['SERVER_PROTOCOL'] . ' 503 Service Unavailable');
 143         }
 144         // and then for human consumption...
 145         echo '<html><body>';
 146         echo '<table align="center"><tr>';
 147         echo '<td style="color:#990000; text-align:center; font-size:large; border-width:1px; '.
 148              '    border-color:#000000; border-style:solid; border-radius: 20px; border-collapse: collapse; '.
 149              '    -moz-border-radius: 20px; padding: 15px">';
 150         echo '<p>Error: Database connection failed.</p>';
 151         echo '<p>It is possible that the database is overloaded or otherwise not running properly.</p>';
 152         echo '<p>The site administrator should also check that the database details have been correctly specified in config.php</p>';
 153         echo '</td></tr></table>';
 154         echo '</body></html>';
 155
 156         if (!empty($CFG->emailconnectionerrorsto)) {
 157             mail($CFG->emailconnectionerrorsto,
 158                  'WARNING: Database connection error: '.$CFG->wwwroot,
 159                  'Connection error: '.$CFG->wwwroot);
 160         }
 161         die;
 162     }
 163
 164 /// Forcing ASSOC mode for ADOdb (some DBs default to FETCH_BOTH)
 165     $db->SetFetchMode(ADODB_FETCH_ASSOC);
 166
 167 /// Starting here we have a correct DB conection but me must avoid
 168 /// to execute any DB transaction until "set names" has been executed
 169 /// some lines below!
 170
 171     error_reporting(E_ALL);       // Show errors from now on.
 172
 173     if (!isset($CFG->prefix)) {   // Just in case it isn't defined in config.php
 174         $CFG->prefix = '';
 175     }
 176
 177
 178 /// Define admin directory
 179
 180     if (!isset($CFG->admin)) {   // Just in case it isn't defined in config.php
 181         $CFG->admin = 'admin';   // This is relative to the wwwroot and dirroot
 182     }
 183
 184 /// Increase memory limits if possible
 185     raise_memory_limit('96M');    // We should never NEED this much but just in case...
 186
 187 /// Load up standard libraries
 188
 189     require_once($CFG->libdir .'/textlib.class.php');   // Functions to handle multibyte strings
 190     require_once($CFG->libdir .'/weblib.php');          // Functions for producing HTML
 191     require_once($CFG->libdir .'/dmllib.php');          // Functions to handle DB data (DML)
 192     require_once($CFG->libdir .'/datalib.php');         // Legacy lib with a big-mix of functions.
 193     require_once($CFG->libdir .'/accesslib.php');       // Access control functions
 194     require_once($CFG->libdir .'/deprecatedlib.php');   // Deprecated functions included for backward compatibility
 195     require_once($CFG->libdir .'/moodlelib.php');       // Other general-purpose functions
 196     require_once($CFG->libdir .'/eventslib.php');       // Events functions
 197     require_once($CFG->libdir .'/grouplib.php');        // Groups functions
 198
 199 /// Disable errors for now - needed for installation when debug enabled in config.php
 200     if (isset($CFG->debug)) {
 201         $originalconfigdebug = $CFG->debug;
 202         unset($CFG->debug);
 203     } else {
 204         $originalconfigdebug = -1;
 205     }
 206
 207 /// Set the client/server and connection to utf8
 208 /// and configure some other specific variables for each db
 209     configure_dbconnection();
 210
 211 /// Load up any configuration from the config table
 212     unset($CFG->rcache);
 213     $CFG = get_config();
 214
 215 /// Turn on SQL logging if required
 216     if (!empty($CFG->logsql)) {
 217         $db->LogSQL();
 218     }
 219
 220 /// Prevent warnings from roles when upgrading with debug on
 221     if (isset($CFG->debug)) {
 222         $originaldatabasedebug = $CFG->debug;
 223         unset($CFG->debug);
 224     } else {
 225         $originaldatabasedebug = -1;
 226     }
 227
 228
 229 /// For now, only needed under apache (and probably unstable in other contexts)
 230     if (function_exists('apache_child_terminate')) {
 231         register_shutdown_function('moodle_request_shutdown');
 232     }
 233
 234 //// Defining the site
 235     if ($SITE = get_site()) {
 236         /**
 237          * If $SITE global from {@link get_site()} is set then SITEID to $SITE->id, otherwise set to 1.
 238          */
 239         define('SITEID', $SITE->id);
 240         /// And the 'default' course
 241         $COURSE = clone($SITE);   // For now.  This will usually get reset later in require_login() etc.
 242     } else {
 243         /**
 244          * @ignore
 245          */
 246         define('SITEID', 1);
 247         /// And the 'default' course
 248         $COURSE = new object;  // no site created yet
 249         $COURSE->id = 1;
 250     }
 251
 252
 253 /// Set error reporting back to normal
 254     if ($originaldatabasedebug == -1) {
 255         $CFG->debug = DEBUG_MINIMAL;
 256     } else {
 257         $CFG->debug = $originaldatabasedebug;
 258     }
 259     if ($originalconfigdebug !== -1) {
 260         $CFG->debug = $originalconfigdebug;
 261     }
 262     unset($originalconfigdebug);
 263     unset($originaldatabasedebug);
 264     error_reporting($CFG->debug);
 265
 266
 267 /// If we want to display Moodle errors, then try and set PHP errors to match
 268     if (!isset($CFG->debugdisplay)) {
 269         //keep it as is during installation
 270     } else if (empty($CFG->debugdisplay)) {
 271         @ini_set('display_errors', '0');
 272         @ini_set('log_errors', '1');
 273     } else {
 274         @ini_set('display_errors', '1');
 275     }
 276
 277 /// Shared-Memory cache init -- will set $MCACHE
 278 /// $MCACHE is a global object that offers at least add(), set() and delete()
 279 /// with similar semantics to the memcached PHP API http://php.net/memcache
 280     if (!empty($CFG->cachetype)) {
 281         if ($CFG->cachetype === 'memcached' && !empty($CFG->memcachedhosts)) {
 282             if (!init_memcached()) {
 283                 debugging("Error initialising memcached");
 284             }
 285         } elseif ($CFG->cachetype === 'eaccelerator') {
 286             if (!init_eaccelerator()) {
 287                 debugging("Error initialising eaccelerator cache");
 288             }
 289         }
 290     } else { // just make sure it is defined
 291         $CFG->cachetype = '';
 292     }
 293 /// Ensure we define rcache - so we can later check for it
 294 /// with a really fast and unambiguous $CFG->rcache === false
 295     if (empty($CFG->rcache)) {
 296         $CFG->rcache = false;
 297     } else {
 298         $CFG->rcache = true;
 299     }
 300
 301 /// Set a default enrolment configuration (see bug 1598)
 302     if (!isset($CFG->enrol)) {
 303         $CFG->enrol = 'manual';
 304     }
 305
 306 /// Set default enabled enrolment plugins
 307     if (!isset($CFG->enrol_plugins_enabled)) {
 308         $CFG->enrol_plugins_enabled = 'manual';
 309     }
 310
 311 /// File permissions on created directories in the $CFG->dataroot
 312
 313     if (empty($CFG->directorypermissions)) {
 314         $CFG->directorypermissions = 0777;      // Must be octal (that's why it's here)
 315     }
 316
 317 /// Calculate and set $CFG->ostype to be used everywhere. Possible values are:
 318 /// - WINDOWS: for any Windows flavour.
 319 /// - UNIX: for the rest
 320 /// Also, $CFG->os can continue being used if more specialization is required
 321     if (stristr(PHP_OS, 'win') && !stristr(PHP_OS, 'darwin')) {
 322         $CFG->ostype = 'WINDOWS';
 323     } else {
 324         $CFG->ostype = 'UNIX';
 325     }
 326     $CFG->os = PHP_OS;
 327
 328 /// Set up default frame target string, based on $CFG->framename
 329     $CFG->frametarget = frametarget();
 330
 331 /// Setup cache dir for Smarty and others
 332     if (!file_exists($CFG->dataroot .'/cache')) {
 333         make_upload_directory('cache');
 334     }
 335
 336 /// Set up smarty template system
 337     //require_once($CFG->libdir .'/smarty/Smarty.class.php');
 338     //$smarty = new Smarty;
 339     //$smarty->template_dir = $CFG->dirroot .'/templates/'. $CFG->template;
 340     //if (!file_exists($CFG->dataroot .'/cache/smarty')) {
 341     //    make_upload_directory('cache/smarty');
 342     //}
 343     //$smarty->compile_dir = $CFG->dataroot .'/cache/smarty';
 344
 345 /// Set up session handling
 346     if(empty($CFG->respectsessionsettings)) {
 347         if (empty($CFG->dbsessions)) {   /// File-based sessions
 348
 349             // Some distros disable GC by setting probability to 0
 350             // overriding the PHP default of 1
 351             // (gc_probability is divided by gc_divisor, which defaults to 1000)
 352             if (ini_get('session.gc_probability') == 0) {
 353                 ini_set('session.gc_probability', 1);
 354             }
 355
 356             if (!empty($CFG->sessiontimeout)) {
 357                 ini_set('session.gc_maxlifetime', $CFG->sessiontimeout);
 358             }
 359
 360             if (!file_exists($CFG->dataroot .'/sessions')) {
 361                 make_upload_directory('sessions');
 362             }
 363             ini_set('session.save_path', $CFG->dataroot .'/sessions');
 364
 365         } else {                         /// Database sessions
 366             ini_set('session.save_handler', 'user');
 367
 368             $ADODB_SESSION_DRIVER  = $CFG->dbtype;
 369             $ADODB_SESSION_CONNECT = $CFG->dbhost;
 370             $ADODB_SESSION_USER    = $CFG->dbuser;
 371             $ADODB_SESSION_PWD     = $CFG->dbpass;
 372             $ADODB_SESSION_DB      = $CFG->dbname;
 373             $ADODB_SESSION_TBL     = $CFG->prefix.'sessions2';
 374             if (!empty($CFG->sessiontimeout)) {
 375                 $ADODB_SESS_LIFE   = $CFG->sessiontimeout;
 376             }
 377
 378             require_once($CFG->libdir. '/adodb/session/adodb-session2.php');
 379         }
 380     }
 381 /// Set sessioncookie variable if it isn't already
 382     if (!isset($CFG->sessioncookie)) {
 383         $CFG->sessioncookie = '';
 384     }
 385
 386 /// Configure ampersands in URLs
 387
 388     @ini_set('arg_separator.output', '&amp;');
 389
 390 /// Location of standard files
 391
 392     $CFG->wordlist    = $CFG->libdir .'/wordlist.txt';
 393     $CFG->javascript  = $CFG->libdir .'/javascript.php';
 394     $CFG->moddata     = 'moddata';
 395
 396
 397 /// A hack to get around magic_quotes_gpc being turned off
 398 /// It is strongly recommended to enable "magic_quotes_gpc"!
 399
 400     if (!ini_get_bool('magic_quotes_gpc') ) {
 401         function addslashes_deep($value) {
 402             $value = is_array($value) ?
 403                     array_map('addslashes_deep', $value) :
 404                     addslashes($value);
 405             return $value;
 406         }
 407         $_POST = array_map('addslashes_deep', $_POST);
 408         $_GET = array_map('addslashes_deep', $_GET);
 409         $_COOKIE = array_map('addslashes_deep', $_COOKIE);
 410         $_REQUEST = array_map('addslashes_deep', $_REQUEST);
 411         if (!empty($_SERVER['REQUEST_URI'])) {
 412             $_SERVER['REQUEST_URI'] = addslashes($_SERVER['REQUEST_URI']);
 413         }
 414         if (!empty($_SERVER['QUERY_STRING'])) {
 415             $_SERVER['QUERY_STRING'] = addslashes($_SERVER['QUERY_STRING']);
 416         }
 417         if (!empty($_SERVER['HTTP_REFERER'])) {
 418             $_SERVER['HTTP_REFERER'] = addslashes($_SERVER['HTTP_REFERER']);
 419         }
 420        if (!empty($_SERVER['PATH_INFO'])) {
 421             $_SERVER['PATH_INFO'] = addslashes($_SERVER['PATH_INFO']);
 422         }
 423         if (!empty($_SERVER['PHP_SELF'])) {
 424             $_SERVER['PHP_SELF'] = addslashes($_SERVER['PHP_SELF']);
 425         }
 426         if (!empty($_SERVER['PATH_TRANSLATED'])) {
 427             $_SERVER['PATH_TRANSLATED'] = addslashes($_SERVER['PATH_TRANSLATED']);
 428         }
 429     }
 430
 431
 432 /// The following code can emulate "register globals" if required.
 433 /// This hack is no longer being applied as of Moodle 1.6 unless you really
 434 /// really want to use it (by defining  $CFG->enableglobalshack = true)
 435
 436     if (!empty($CFG->enableglobalshack)) {
 437         if (!empty($CFG->detect_unchecked_vars)) {
 438             global $UNCHECKED_VARS;
 439             $UNCHECKED_VARS->url = $_SERVER['PHP_SELF'];
 440             $UNCHECKED_VARS->vars = array();
 441         }
 442
 443         if (isset($_GET)) {
 444             extract($_GET, EXTR_SKIP);    // Skip existing variables, ie CFG
 445             if (!empty($CFG->detect_unchecked_vars)) {
 446                 foreach ($_GET as $key => $val) {
 447                     $UNCHECKED_VARS->vars[$key]=$val;
 448                 }
 449             }
 450         }
 451         if (isset($_POST)) {
 452             extract($_POST, EXTR_SKIP);   // Skip existing variables, ie CFG
 453             if (!empty($CFG->detect_unchecked_vars)) {
 454                 foreach ($_POST as $key => $val) {
 455                     $UNCHECKED_VARS->vars[$key]=$val;
 456                 }
 457             }
 458         }
 459         if (isset($_SERVER)) {
 460             extract($_SERVER);
 461         }
 462     }
 463
 464
 465 /// Load up global environment variables
 466
 467     class object {};
 468
 469     //discard session ID from POST, GET and globals to tighten security,
 470     //this session fixation prevention can not be used in cookieless mode
 471     if (empty($CFG->usesid)) {
 472         unset(${'MoodleSession'.$CFG->sessioncookie});
 473         unset($_GET['MoodleSession'.$CFG->sessioncookie]);
 474         unset($_POST['MoodleSession'.$CFG->sessioncookie]);
 475     }
 476     //compatibility hack for Moodle Cron, cookies not deleted, but set to "deleted" - should not be needed with $nomoodlecookie in cron.php now
 477     if (!empty($_COOKIE['MoodleSession'.$CFG->sessioncookie]) && $_COOKIE['MoodleSession'.$CFG->sessioncookie] == "deleted") {
 478         unset($_COOKIE['MoodleSession'.$CFG->sessioncookie]);
 479     }
 480     if (!empty($_COOKIE['MoodleSessionTest'.$CFG->sessioncookie]) && $_COOKIE['MoodleSessionTest'.$CFG->sessioncookie] == "deleted") {
 481         unset($_COOKIE['MoodleSessionTest'.$CFG->sessioncookie]);
 482     }
 483     if (!empty($CFG->usesid) && empty($_COOKIE['MoodleSession'.$CFG->sessioncookie])) {
 484         require_once("$CFG->dirroot/lib/cookieless.php");
 485         sid_start_ob();
 486     }
 487
 488     if (empty($nomoodlecookie)) {
 489         session_name('MoodleSession'.$CFG->sessioncookie);
 490         @session_start();
 491         if (! isset($_SESSION['SESSION'])) {
 492             $_SESSION['SESSION'] = new object;
 493             $_SESSION['SESSION']->session_test = random_string(10);
 494             if (!empty($_COOKIE['MoodleSessionTest'.$CFG->sessioncookie])) {
 495                 $_SESSION['SESSION']->has_timed_out = true;
 496             }
 497             setcookie('MoodleSessionTest'.$CFG->sessioncookie, $_SESSION['SESSION']->session_test, 0, '/');
 498             $_COOKIE['MoodleSessionTest'.$CFG->sessioncookie] = $_SESSION['SESSION']->session_test;
 499         }
 500         if (! isset($_SESSION['USER']))    {
 501             $_SESSION['USER']    = new object;
 502         }
 503
 504         $SESSION = &$_SESSION['SESSION'];   // Makes them easier to reference
 505         $USER    = &$_SESSION['USER'];
 506         if (!isset($USER->id)) {
 507             $USER->id = 0; // to enable proper function of $CFG->notloggedinroleid hack
 508         }
 509     }
 510     else {
 511         $SESSION  = NULL;
 512         $USER     = new object();
 513         $USER->id = 0; // user not logged in when session disabled
 514     }
 515
 516     if (defined('FULLME')) {     // Usually in command-line scripts like admin/cron.php
 517         $FULLME = FULLME;
 518         $ME = FULLME;
 519     } else {
 520         $FULLME = qualified_me();
 521         $ME = strip_querystring($FULLME);
 522     }
 523
 524 /// In VERY rare cases old PHP server bugs (it has been found on PHP 4.1.2 running
 525 /// as a CGI under IIS on Windows) may require that you uncomment the following:
 526 //  session_register("USER");
 527 //  session_register("SESSION");
 528
 529
 530
 531 /// Load up theme variables (colours etc)
 532
 533     if (!isset($CFG->themedir)) {
 534         $CFG->themedir = $CFG->dirroot.'/theme';
 535         $CFG->themewww = $CFG->wwwroot.'/theme';
 536     }
 537     $CFG->httpsthemewww = $CFG->themewww;
 538
 539     if (isset($_GET['theme'])) {
 540         if ($CFG->allowthemechangeonurl || confirm_sesskey()) {
 541             $themename = clean_param($_GET['theme'], PARAM_SAFEDIR);
 542             if (($themename != '') and file_exists($CFG->themedir.'/'.$themename)) {
 543                 $SESSION->theme = $themename;
 544             }
 545             unset($themename);
 546         }
 547     }
 548
 549     if (!isset($CFG->theme)) {
 550         $CFG->theme = 'standardwhite';
 551     }
 552
 553 /// now do a session test to prevent random user switching - observed on some PHP/Apache combinations,
 554 /// disable checks when working in cookieless mode
 555     if (empty($CFG->usesid) || !empty($_COOKIE['MoodleSession'.$CFG->sessioncookie])) {
 556         if ($SESSION != NULL) {
 557             if (empty($_COOKIE['MoodleSessionTest'.$CFG->sessioncookie])) {
 558                 report_session_error();
 559             } else if (isset($SESSION->session_test) && $_COOKIE['MoodleSessionTest'.$CFG->sessioncookie] != $SESSION->session_test) {
 560                 report_session_error();
 561             }
 562         }
 563     }
 564
 565
 566 /// Set language/locale of printed times.  If user has chosen a language that
 567 /// that is different from the site language, then use the locale specified
 568 /// in the language file.  Otherwise, if the admin hasn't specified a locale
 569 /// then use the one from the default language.  Otherwise (and this is the
 570 /// majority of cases), use the stored locale specified by admin.
 571     if ($SESSION !== NULL && isset($_GET['lang']) && ($lang = clean_param($_GET['lang'], PARAM_SAFEDIR))) {
 572         if (file_exists($CFG->dataroot .'/lang/'. $lang) or file_exists($CFG->dirroot .'/lang/'. $lang)) {
 573             $SESSION->lang = $lang;
 574         } else if (file_exists($CFG->dataroot.'/lang/'.$lang.'_utf8') or
 575                    file_exists($CFG->dirroot .'/lang/'.$lang.'_utf8')) {
 576             $SESSION->lang = $lang.'_utf8';
 577         }
 578     }
 579
 580     setup_lang_from_browser();
 581
 582     unset($lang);
 583
 584     if (empty($CFG->lang)) {
 585         if (empty($SESSION->lang)) {
 586             $CFG->lang = 'en_utf8';
 587         } else {
 588             $CFG->lang = $SESSION->lang;
 589         }
 590     }
 591
 592     // set default locale and themes - might be changed again later from require_login()
 593     course_setup();
 594
 595     if (!empty($CFG->opentogoogle)) {
 596         if (empty($USER->id)) {  // Ignore anyone logged in
 597             if (!empty($_SERVER['HTTP_USER_AGENT'])) {
 598                 if (strpos($_SERVER['HTTP_USER_AGENT'], 'Googlebot') !== false ) {
 599                     $USER = guest_user();
 600                 } else if (strpos($_SERVER['HTTP_USER_AGENT'], 'google.com') !== false ) {
 601                     $USER = guest_user();
 602                 } else if (strpos($_SERVER['HTTP_USER_AGENT'], 'Yahoo! Slurp') !== false ) {
 603                     $USER = guest_user();
 604                 } else if (strpos($_SERVER['HTTP_USER_AGENT'], 'MSNBOT') !== false ) {
 605                     $USER = guest_user();
 606                 }
 607             }
 608             if (empty($USER) && !empty($_SERVER['HTTP_REFERER'])) {
 609                 if (strpos($_SERVER['HTTP_REFERER'], 'google') !== false ) {
 610                     $USER = guest_user();
 611                 } else if (strpos($_SERVER['HTTP_REFERER'], 'altavista') !== false ) {
 612                     $USER = guest_user();
 613                 }
 614             }
 615             if (!empty($USER)) {
 616                 load_all_capabilities();
 617             }
 618         }
 619     }
 620
 621     if ($CFG->theme == 'standard' or $CFG->theme == 'standardwhite') {    // Temporary measure to help with XHTML validation
 622         if (isset($_SERVER['HTTP_USER_AGENT']) and empty($_SESSION['USER']->id)) {      // Allow W3CValidator in as user called w3cvalidator (or guest)
 623             if ((strpos($_SERVER['HTTP_USER_AGENT'], 'W3C_Validator') !== false) or
 624                 (strpos($_SERVER['HTTP_USER_AGENT'], 'Cynthia') !== false )) {
 625                 if ($USER = get_complete_user_data("username", "w3cvalidator")) {
 626                     $USER->ignoresesskey = true;
 627                 } else {
 628                     $USER = guest_user();
 629                 }
 630             }
 631         }
 632     }
 633
 634 /// Apache log intergration. In apache conf file one can use ${MOODULEUSER}n in
 635 /// LogFormat to get the current logged in username in moodle.
 636     if ($USER && function_exists('apache_note') && !empty($CFG->apacheloguser)) {
 637         $apachelog_username = clean_filename($USER->username);
 638         $apachelog_name = clean_filename($USER->firstname. " ".$USER->lastname);
 639         $apachelog_userid = $USER->id;
 640         if (isset($USER->realuser)) {
 641             if ($realuser = get_record('user', 'id', $USER->realuser)) {
 642                 $apachelog_username = clean_filename($realuser->username." as ".$apachelog_username);
 643                 $apachelog_name = clean_filename($realuser->firstname." ".$realuser->lastname ." as ".$apachelog_name);
 644                 $apachelog_userid = clean_filename($realuser->id." as ".$apachelog_userid);
 645             }
 646         }
 647         switch ($CFG->apacheloguser) {
 648             case 3:
 649                 $logname = $apachelog_username;
 650                 break;
 651             case 2:
 652                 $logname = $apachelog_name;
 653                 break;
 654             case 1:
 655             default:
 656                 $logname = $apachelog_userid;
 657                 break;
 658         }
 659         apache_note('MOODLEUSER', $logname);
 660     }
 661
 662 /// Adjust ALLOWED_TAGS
 663     adjust_allowed_tags();
 664
 665
 666 /// Use a custom script replacement if one exists
 667     if (!empty($CFG->customscripts)) {
 668         if (($customscript = custom_script_path()) !== false) {
 669             require ($customscript);
 670         }
 671     }
 672
 673 /// note: we can not block non utf-8 installatrions here, because empty mysql database
 674 /// might be converted to utf-8 in admin/index.php during installation
 675 ?>