lib/setuplib.php

   1 <?php
   2
   3 // This file is part of Moodle - http://moodle.org/
   4 //
   5 // Moodle is free software: you can redistribute it and/or modify
   6 // it under the terms of the GNU General Public License as published by
   7 // the Free Software Foundation, either version 3 of the License, or
   8 // (at your option) any later version.
   9 //
  10 // Moodle is distributed in the hope that it will be useful,
  11 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 // GNU General Public License for more details.
  14 //
  15 // You should have received a copy of the GNU General Public License
  16 // along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
  17
  18
  19 /**
  20  * These functions are required very early in the Moodle
  21  * setup process, before any of the main libraries are
  22  * loaded.
  23  *
  24  * @package    core
  25  * @subpackage lib
  26  * @copyright  1999 onwards Martin Dougiamas  {@link http://moodle.com}
  27  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  28  */
  29
  30 defined('MOODLE_INTERNAL') || die();
  31
  32 /// Debug levels ///
  33 /** no warnings at all */
  34 define('DEBUG_NONE', 0);
  35 /** E_ERROR | E_PARSE */
  36 define('DEBUG_MINIMAL', 5);
  37 /** E_ERROR | E_PARSE | E_WARNING | E_NOTICE */
  38 define('DEBUG_NORMAL', 15);
  39 /** E_ALL without E_STRICT for now, do show recoverable fatal errors */
  40 define('DEBUG_ALL', 6143);
  41 /** DEBUG_ALL with extra Moodle debug messages - (DEBUG_ALL | 32768) */
  42 define('DEBUG_DEVELOPER', 38911);
  43
  44 /** Remove any memory limits */
  45 define('MEMORY_UNLIMITED', -1);
  46 /** Standard memory limit for given platform */
  47 define('MEMORY_STANDARD', -2);
  48 /**
  49  * Large memory limit for given platform - used in cron, upgrade, and other places that need a lot of memory.
  50  * Can be overridden with $CFG->extramemorylimit setting.
  51  */
  52 define('MEMORY_EXTRA', -3);
  53 /** Extremely large memory limit - not recommended for standard scripts */
  54 define('MEMORY_HUGE', -4);
  55
  56 /**
  57  * Software maturity levels used by the core and plugins
  58  */
  59 define('MATURITY_ALPHA',    50);    // internals can be tested using white box techniques
  60 define('MATURITY_BETA',     100);   // feature complete, ready for preview and testing
  61 define('MATURITY_RC',       150);   // tested, will be released unless there are fatal bugs
  62 define('MATURITY_STABLE',   200);   // ready for production deployment
  63
  64 /**
  65  * Special value that can be used in $plugin->dependencies in version.php files.
  66  */
  67 define('ANY_VERSION', 'any');
  68
  69
  70 /**
  71  * Simple class. It is usually used instead of stdClass because it looks
  72  * more familiar to Java developers ;-) Do not use for type checking of
  73  * function parameters. Please use stdClass instead.
  74  *
  75  * @package    core
  76  * @subpackage lib
  77  * @copyright  2009 Petr Skoda  {@link http://skodak.org}
  78  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  79  * @deprecated since 2.0
  80  */
  81 class object extends stdClass {};
  82
  83 /**
  84  * Base Moodle Exception class
  85  *
  86  * Although this class is defined here, you cannot throw a moodle_exception until
  87  * after moodlelib.php has been included (which will happen very soon).
  88  *
  89  * @package    core
  90  * @subpackage lib
  91  * @copyright  2008 Petr Skoda  {@link http://skodak.org}
  92  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  93  */
  94 class moodle_exception extends Exception {
  95     public $errorcode;
  96     public $module;
  97     public $a;
  98     public $link;
  99     public $debuginfo;
 100
 101     /**
 102      * Constructor
 103      * @param string $errorcode The name of the string from error.php to print
 104      * @param string $module name of module
 105      * @param string $link The url where the user will be prompted to continue. If no url is provided the user will be directed to the site index page.
 106      * @param object $a Extra words and phrases that might be required in the error string
 107      * @param string $debuginfo optional debugging information
 108      */
 109     function __construct($errorcode, $module='', $link='', $a=NULL, $debuginfo=null) {
 110         if (empty($module) || $module == 'moodle' || $module == 'core') {
 111             $module = 'error';
 112         }
 113
 114         $this->errorcode = $errorcode;
 115         $this->module    = $module;
 116         $this->link      = $link;
 117         $this->a         = $a;
 118         $this->debuginfo = $debuginfo;
 119
 120         if (get_string_manager()->string_exists($errorcode, $module)) {
 121             $message = get_string($errorcode, $module, $a);
 122         } else {
 123             $message = $module . '/' . $errorcode;
 124         }
 125
 126         parent::__construct($message, 0);
 127     }
 128 }
 129
 130 /**
 131  * Course/activity access exception.
 132  *
 133  * This exception is thrown from require_login()
 134  *
 135  * @package    core
 136  * @subpackage lib
 137  * @copyright  2010 Petr Skoda  {@link http://skodak.org}
 138  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 139  */
 140 class require_login_exception extends moodle_exception {
 141     function __construct($debuginfo) {
 142         parent::__construct('requireloginerror', 'error', '', NULL, $debuginfo);
 143     }
 144 }
 145
 146 /**
 147  * Web service parameter exception class
 148  * @deprecated since Moodle 2.2 - use moodle exception instead
 149  * This exception must be thrown to the web service client when a web service parameter is invalid
 150  * The error string is gotten from webservice.php
 151  */
 152 class webservice_parameter_exception extends moodle_exception {
 153     /**
 154      * Constructor
 155      * @param string $errorcode The name of the string from webservice.php to print
 156      * @param string $a The name of the parameter
 157      */
 158     function __construct($errorcode=null, $a = '', $debuginfo = null) {
 159         parent::__construct($errorcode, 'webservice', '', $a, $debuginfo);
 160     }
 161 }
 162
 163 /**
 164  * Exceptions indicating user does not have permissions to do something
 165  * and the execution can not continue.
 166  *
 167  * @package    core
 168  * @subpackage lib
 169  * @copyright  2009 Petr Skoda  {@link http://skodak.org}
 170  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 171  */
 172 class required_capability_exception extends moodle_exception {
 173     function __construct($context, $capability, $errormessage, $stringfile) {
 174         $capabilityname = get_capability_string($capability);
 175         if ($context->contextlevel == CONTEXT_MODULE and preg_match('/:view$/', $capability)) {
 176             // we can not go to mod/xx/view.php because we most probably do not have cap to view it, let's go to course instead
 177             $paranetcontext = get_context_instance_by_id(get_parent_contextid($context));
 178             $link = get_context_url($paranetcontext);
 179         } else {
 180             $link = get_context_url($context);
 181         }
 182         parent::__construct($errormessage, $stringfile, $link, $capabilityname);
 183     }
 184 }
 185
 186 /**
 187  * Exception indicating programming error, must be fixed by a programer. For example
 188  * a core API might throw this type of exception if a plugin calls it incorrectly.
 189  *
 190  * @package    core
 191  * @subpackage lib
 192  * @copyright  2008 Petr Skoda  {@link http://skodak.org}
 193  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 194  */
 195 class coding_exception extends moodle_exception {
 196     /**
 197      * Constructor
 198      * @param string $hint short description of problem
 199      * @param string $debuginfo detailed information how to fix problem
 200      */
 201     function __construct($hint, $debuginfo=null) {
 202         parent::__construct('codingerror', 'debug', '', $hint, $debuginfo);
 203     }
 204 }
 205
 206 /**
 207  * Exception indicating malformed parameter problem.
 208  * This exception is not supposed to be thrown when processing
 209  * user submitted data in forms. It is more suitable
 210  * for WS and other low level stuff.
 211  *
 212  * @package    core
 213  * @subpackage lib
 214  * @copyright  2009 Petr Skoda  {@link http://skodak.org}
 215  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 216  */
 217 class invalid_parameter_exception extends moodle_exception {
 218     /**
 219      * Constructor
 220      * @param string $debuginfo some detailed information
 221      */
 222     function __construct($debuginfo=null) {
 223         parent::__construct('invalidparameter', 'debug', '', null, $debuginfo);
 224     }
 225 }
 226
 227 /**
 228  * Exception indicating malformed response problem.
 229  * This exception is not supposed to be thrown when processing
 230  * user submitted data in forms. It is more suitable
 231  * for WS and other low level stuff.
 232  */
 233 class invalid_response_exception extends moodle_exception {
 234     /**
 235      * Constructor
 236      * @param string $debuginfo some detailed information
 237      */
 238     function __construct($debuginfo=null) {
 239         parent::__construct('invalidresponse', 'debug', '', null, $debuginfo);
 240     }
 241 }
 242
 243 /**
 244  * An exception that indicates something really weird happened. For example,
 245  * if you do switch ($context->contextlevel), and have one case for each
 246  * CONTEXT_... constant. You might throw an invalid_state_exception in the
 247  * default case, to just in case something really weird is going on, and
 248  * $context->contextlevel is invalid - rather than ignoring this possibility.
 249  *
 250  * @package    core
 251  * @subpackage lib
 252  * @copyright  2009 onwards Martin Dougiamas  {@link http://moodle.com}
 253  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 254  */
 255 class invalid_state_exception extends moodle_exception {
 256     /**
 257      * Constructor
 258      * @param string $hint short description of problem
 259      * @param string $debuginfo optional more detailed information
 260      */
 261     function __construct($hint, $debuginfo=null) {
 262         parent::__construct('invalidstatedetected', 'debug', '', $hint, $debuginfo);
 263     }
 264 }
 265
 266 /**
 267  * An exception that indicates incorrect permissions in $CFG->dataroot
 268  *
 269  * @package    core
 270  * @subpackage lib
 271  * @copyright  2010 Petr Skoda {@link http://skodak.org}
 272  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 273  */
 274 class invalid_dataroot_permissions extends moodle_exception {
 275     /**
 276      * Constructor
 277      * @param string $debuginfo optional more detailed information
 278      */
 279     function __construct($debuginfo = NULL) {
 280         parent::__construct('invaliddatarootpermissions', 'error', '', NULL, $debuginfo);
 281     }
 282 }
 283
 284 /**
 285  * An exception that indicates that file can not be served
 286  *
 287  * @package    core
 288  * @subpackage lib
 289  * @copyright  2010 Petr Skoda {@link http://skodak.org}
 290  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 291  */
 292 class file_serving_exception extends moodle_exception {
 293     /**
 294      * Constructor
 295      * @param string $debuginfo optional more detailed information
 296      */
 297     function __construct($debuginfo = NULL) {
 298         parent::__construct('cannotservefile', 'error', '', NULL, $debuginfo);
 299     }
 300 }
 301
 302 /**
 303  * Default exception handler, uncaught exceptions are equivalent to error() in 1.9 and earlier
 304  *
 305  * @param Exception $ex
 306  * @return void -does not return. Terminates execution!
 307  */
 308 function default_exception_handler($ex) {
 309     global $CFG, $DB, $OUTPUT, $USER, $FULLME, $SESSION;
 310
 311     // detect active db transactions, rollback and log as error
 312     abort_all_db_transactions();
 313
 314     if (($ex instanceof required_capability_exception) && !CLI_SCRIPT && !AJAX_SCRIPT && !empty($CFG->autologinguests) && !empty($USER->autologinguest)) {
 315         $SESSION->wantsurl = $FULLME;
 316         redirect(get_login_url());
 317     }
 318
 319     $info = get_exception_info($ex);
 320
 321     if (debugging('', DEBUG_MINIMAL)) {
 322         $logerrmsg = "Default exception handler: ".$info->message.' Debug: '.$info->debuginfo."\n".format_backtrace($info->backtrace, true);
 323         error_log($logerrmsg);
 324     }
 325
 326     if (is_early_init($info->backtrace)) {
 327         echo bootstrap_renderer::early_error($info->message, $info->moreinfourl, $info->link, $info->backtrace, $info->debuginfo);
 328     } else {
 329         try {
 330             if ($DB) {
 331                 // If you enable db debugging and exception is thrown, the print footer prints a lot of rubbish
 332                 $DB->set_debug(0);
 333             }
 334             echo $OUTPUT->fatal_error($info->message, $info->moreinfourl, $info->link, $info->backtrace, $info->debuginfo);
 335         } catch (Exception $out_ex) {
 336             // default exception handler MUST not throw any exceptions!!
 337             // the problem here is we do not know if page already started or not, we only know that somebody messed up in outputlib or theme
 338             // so we just print at least something instead of "Exception thrown without a stack frame in Unknown on line 0":-(
 339             if (CLI_SCRIPT or AJAX_SCRIPT) {
 340                 // just ignore the error and send something back using the safest method
 341                 echo bootstrap_renderer::early_error($info->message, $info->moreinfourl, $info->link, $info->backtrace, $info->debuginfo);
 342             } else {
 343                 echo bootstrap_renderer::early_error_content($info->message, $info->moreinfourl, $info->link, $info->backtrace, $info->debuginfo);
 344                 $outinfo = get_exception_info($out_ex);
 345                 echo bootstrap_renderer::early_error_content($outinfo->message, $outinfo->moreinfourl, $outinfo->link, $outinfo->backtrace, $outinfo->debuginfo);
 346             }
 347         }
 348     }
 349
 350     exit(1); // General error code
 351 }
 352
 353 /**
 354  * Default error handler, prevents some white screens.
 355  * @param int $errno
 356  * @param string $errstr
 357  * @param string $errfile
 358  * @param int $errline
 359  * @param array $errcontext
 360  * @return bool false means use default error handler
 361  */
 362 function default_error_handler($errno, $errstr, $errfile, $errline, $errcontext) {
 363     if ($errno == 4096) {
 364         //fatal catchable error
 365         throw new coding_exception('PHP catchable fatal error', $errstr);
 366     }
 367     return false;
 368 }
 369
 370 /**
 371  * Unconditionally abort all database transactions, this function
 372  * should be called from exception handlers only.
 373  * @return void
 374  */
 375 function abort_all_db_transactions() {
 376     global $CFG, $DB, $SCRIPT;
 377
 378     // default exception handler MUST not throw any exceptions!!
 379
 380     if ($DB && $DB->is_transaction_started()) {
 381         error_log('Database transaction aborted automatically in ' . $CFG->dirroot . $SCRIPT);
 382         // note: transaction blocks should never change current $_SESSION
 383         $DB->force_transaction_rollback();
 384     }
 385 }
 386
 387 /**
 388  * This function encapsulates the tests for whether an exception was thrown in
 389  * early init -- either during setup.php or during init of $OUTPUT.
 390  *
 391  * If another exception is thrown then, and if we do not take special measures,
 392  * we would just get a very cryptic message "Exception thrown without a stack
 393  * frame in Unknown on line 0". That makes debugging very hard, so we do take
 394  * special measures in default_exception_handler, with the help of this function.
 395  *
 396  * @param array $backtrace the stack trace to analyse.
 397  * @return boolean whether the stack trace is somewhere in output initialisation.
 398  */
 399 function is_early_init($backtrace) {
 400     $dangerouscode = array(
 401         array('function' => 'header', 'type' => '->'),
 402         array('class' => 'bootstrap_renderer'),
 403         array('file' => dirname(__FILE__).'/setup.php'),
 404     );
 405     foreach ($backtrace as $stackframe) {
 406         foreach ($dangerouscode as $pattern) {
 407             $matches = true;
 408             foreach ($pattern as $property => $value) {
 409                 if (!isset($stackframe[$property]) || $stackframe[$property] != $value) {
 410                     $matches = false;
 411                 }
 412             }
 413             if ($matches) {
 414                 return true;
 415             }
 416         }
 417     }
 418     return false;
 419 }
 420
 421 /**
 422  * Abort execution by throwing of a general exception,
 423  * default exception handler displays the error message in most cases.
 424  *
 425  * @param string $errorcode The name of the language string containing the error message.
 426  *      Normally this should be in the error.php lang file.
 427  * @param string $module The language file to get the error message from.
 428  * @param string $link The url where the user will be prompted to continue.
 429  *      If no url is provided the user will be directed to the site index page.
 430  * @param object $a Extra words and phrases that might be required in the error string
 431  * @param string $debuginfo optional debugging information
 432  * @return void, always throws exception!
 433  */
 434 function print_error($errorcode, $module = 'error', $link = '', $a = null, $debuginfo = null) {
 435     throw new moodle_exception($errorcode, $module, $link, $a, $debuginfo);
 436 }
 437
 438 /**
 439  * Returns detailed information about specified exception.
 440  * @param exception $ex
 441  * @return object
 442  */
 443 function get_exception_info($ex) {
 444     global $CFG, $DB, $SESSION;
 445
 446     if ($ex instanceof moodle_exception) {
 447         $errorcode = $ex->errorcode;
 448         $module = $ex->module;
 449         $a = $ex->a;
 450         $link = $ex->link;
 451         $debuginfo = $ex->debuginfo;
 452     } else {
 453         $errorcode = 'generalexceptionmessage';
 454         $module = 'error';
 455         $a = $ex->getMessage();
 456         $link = '';
 457         $debuginfo = null;
 458     }
 459
 460     $backtrace = $ex->getTrace();
 461     $place = array('file'=>$ex->getFile(), 'line'=>$ex->getLine(), 'exception'=>get_class($ex));
 462     array_unshift($backtrace, $place);
 463
 464     // Be careful, no guarantee moodlelib.php is loaded.
 465     if (empty($module) || $module == 'moodle' || $module == 'core') {
 466         $module = 'error';
 467     }
 468     if (function_exists('get_string_manager')) {
 469         if (get_string_manager()->string_exists($errorcode, $module)) {
 470             $message = get_string($errorcode, $module, $a);
 471         } elseif ($module == 'error' && get_string_manager()->string_exists($errorcode, 'moodle')) {
 472             // Search in moodle file if error specified - needed for backwards compatibility
 473             $message = get_string($errorcode, 'moodle', $a);
 474         } else {
 475             $message = $module . '/' . $errorcode;
 476         }
 477     } else {
 478         $message = $module . '/' . $errorcode;
 479     }
 480
 481     // Be careful, no guarantee weblib.php is loaded.
 482     if (function_exists('clean_text')) {
 483         $message = clean_text($message);
 484     } else {
 485         $message = htmlspecialchars($message);
 486     }
 487
 488     if (!empty($CFG->errordocroot)) {
 489         $errordoclink = $CFG->errordocroot . '/en/';
 490     } else {
 491         $errordoclink = get_docs_url();
 492     }
 493
 494     if ($module === 'error') {
 495         $modulelink = 'moodle';
 496     } else {
 497         $modulelink = $module;
 498     }
 499     $moreinfourl = $errordoclink . 'error/' . $modulelink . '/' . $errorcode;
 500
 501     if (empty($link)) {
 502         if (!empty($SESSION->fromurl)) {
 503             $link = $SESSION->fromurl;
 504             unset($SESSION->fromurl);
 505         } else {
 506             $link = $CFG->wwwroot .'/';
 507         }
 508     }
 509
 510     // when printing an error the continue button should never link offsite
 511     if (stripos($link, $CFG->wwwroot) === false &&
 512         stripos($link, $CFG->httpswwwroot) === false) {
 513         $link = $CFG->wwwroot.'/';
 514     }
 515
 516     $info = new stdClass();
 517     $info->message     = $message;
 518     $info->errorcode   = $errorcode;
 519     $info->backtrace   = $backtrace;
 520     $info->link        = $link;
 521     $info->moreinfourl = $moreinfourl;
 522     $info->a           = $a;
 523     $info->debuginfo   = $debuginfo;
 524
 525     return $info;
 526 }
 527
 528 /**
 529  * Returns the Moodle Docs URL in the users language
 530  *
 531  * @global object
 532  * @param string $path the end of the URL.
 533  * @return string The MoodleDocs URL in the user's language. for example {@link http://docs.moodle.org/en/ http://docs.moodle.org/en/$path}
 534  */
 535 function get_docs_url($path=null) {
 536     global $CFG;
 537     // Check that $CFG->release has been set up, during installation it won't be.
 538     if (empty($CFG->release)) {
 539         // It's not there yet so look at version.php
 540         include($CFG->dirroot.'/version.php');
 541     } else {
 542         // We can use $CFG->release and avoid having to include version.php
 543         $release = $CFG->release;
 544     }
 545     // Attempt to match the branch from the release
 546     if (preg_match('/^(.)\.(.)/', $release, $matches)) {
 547         // We should ALWAYS get here
 548         $branch = $matches[1].$matches[2];
 549     } else {
 550         // We should never get here but in case we do lets set $branch to .
 551         // the smart one's will know that this is the current directory
 552         // and the smarter ones will know that there is some smart matching
 553         // that will ensure people end up at the latest version of the docs.
 554         $branch = '.';
 555     }
 556     if (!empty($CFG->docroot)) {
 557         return $CFG->docroot . '/' . $branch . '/' . current_language() . '/' . $path;
 558     } else {
 559         return 'http://docs.moodle.org/'. $branch . '/en/' . $path;
 560     }
 561 }
 562
 563 /**
 564  * Formats a backtrace ready for output.
 565  *
 566  * @param array $callers backtrace array, as returned by debug_backtrace().
 567  * @param boolean $plaintext if false, generates HTML, if true generates plain text.
 568  * @return string formatted backtrace, ready for output.
 569  */
 570 function format_backtrace($callers, $plaintext = false) {
 571     // do not use $CFG->dirroot because it might not be available in destructors
 572     $dirroot = dirname(dirname(__FILE__));
 573
 574     if (empty($callers)) {
 575         return '';
 576     }
 577
 578     $from = $plaintext ? '' : '<ul style="text-align: left">';
 579     foreach ($callers as $caller) {
 580         if (!isset($caller['line'])) {
 581             $caller['line'] = '?'; // probably call_user_func()
 582         }
 583         if (!isset($caller['file'])) {
 584             $caller['file'] = 'unknownfile'; // probably call_user_func()
 585         }
 586         $from .= $plaintext ? '* ' : '<li>';
 587         $from .= 'line ' . $caller['line'] . ' of ' . str_replace($dirroot, '', $caller['file']);
 588         if (isset($caller['function'])) {
 589             $from .= ': call to ';
 590             if (isset($caller['class'])) {
 591                 $from .= $caller['class'] . $caller['type'];
 592             }
 593             $from .= $caller['function'] . '()';
 594         } else if (isset($caller['exception'])) {
 595             $from .= ': '.$caller['exception'].' thrown';
 596         }
 597         $from .= $plaintext ? "\n" : '</li>';
 598     }
 599     $from .= $plaintext ? '' : '</ul>';
 600
 601     return $from;
 602 }
 603
 604 /**
 605  * This function makes the return value of ini_get consistent if you are
 606  * setting server directives through the .htaccess file in apache.
 607  *
 608  * Current behavior for value set from php.ini On = 1, Off = [blank]
 609  * Current behavior for value set from .htaccess On = On, Off = Off
 610  * Contributed by jdell @ unr.edu
 611  *
 612  * @param string $ini_get_arg The argument to get
 613  * @return bool True for on false for not
 614  */
 615 function ini_get_bool($ini_get_arg) {
 616     $temp = ini_get($ini_get_arg);
 617
 618     if ($temp == '1' or strtolower($temp) == 'on') {
 619         return true;
 620     }
 621     return false;
 622 }
 623
 624 /**
 625  * This function verifies the sanity of PHP configuration
 626  * and stops execution if anything critical found.
 627  */
 628 function setup_validate_php_configuration() {
 629    // this must be very fast - no slow checks here!!!
 630
 631    if (ini_get_bool('register_globals')) {
 632        print_error('globalswarning', 'admin');
 633    }
 634    if (ini_get_bool('session.auto_start')) {
 635        print_error('sessionautostartwarning', 'admin');
 636    }
 637    if (ini_get_bool('magic_quotes_runtime')) {
 638        print_error('fatalmagicquotesruntime', 'admin');
 639    }
 640 }
 641
 642 /**
 643  * Initialise global $CFG variable
 644  * @return void
 645  */
 646 function initialise_cfg() {
 647     global $CFG, $DB;
 648
 649     try {
 650         if ($DB) {
 651             $localcfg = $DB->get_records_menu('config', array(), '', 'name,value');
 652             foreach ($localcfg as $name=>$value) {
 653                 if (property_exists($CFG, $name)) {
 654                     // config.php settings always take precedence
 655                     continue;
 656                 }
 657                 $CFG->{$name} = $value;
 658             }
 659         }
 660     } catch (dml_exception $e) {
 661         // most probably empty db, going to install soon
 662     }
 663 }
 664
 665 /**
 666  * Initialises $FULLME and friends. Private function. Should only be called from
 667  * setup.php.
 668  */
 669 function initialise_fullme() {
 670     global $CFG, $FULLME, $ME, $SCRIPT, $FULLSCRIPT;
 671
 672     // Detect common config error.
 673     if (substr($CFG->wwwroot, -1) == '/') {
 674         print_error('wwwrootslash', 'error');
 675     }
 676
 677     if (CLI_SCRIPT) {
 678         initialise_fullme_cli();
 679         return;
 680     }
 681
 682     $rurl = setup_get_remote_url();
 683     $wwwroot = parse_url($CFG->wwwroot.'/');
 684
 685     if (empty($rurl['host'])) {
 686         // missing host in request header, probably not a real browser, let's ignore them
 687
 688     } else if (!empty($CFG->reverseproxy)) {
 689         // $CFG->reverseproxy specifies if reverse proxy server used
 690         // Used in load balancing scenarios.
 691         // Do not abuse this to try to solve lan/wan access problems!!!!!
 692
 693     } else {
 694         if (($rurl['host'] !== $wwwroot['host']) or (!empty($wwwroot['port']) and $rurl['port'] != $wwwroot['port'])) {
 695             // Explain the problem and redirect them to the right URL
 696             if (!defined('NO_MOODLE_COOKIES')) {
 697                 define('NO_MOODLE_COOKIES', true);
 698             }
 699             redirect($CFG->wwwroot, get_string('wwwrootmismatch', 'error', $CFG->wwwroot), 3);
 700         }
 701     }
 702
 703     // Check that URL is under $CFG->wwwroot.
 704     if (strpos($rurl['path'], $wwwroot['path']) === 0) {
 705         $SCRIPT = substr($rurl['path'], strlen($wwwroot['path'])-1);
 706     } else {
 707         // Probably some weird external script
 708         $SCRIPT = $FULLSCRIPT = $FULLME = $ME = null;
 709         return;
 710     }
 711
 712     // $CFG->sslproxy specifies if external SSL appliance is used
 713     // (That is, the Moodle server uses http, with an external box translating everything to https).
 714     if (empty($CFG->sslproxy)) {
 715         if ($rurl['scheme'] === 'http' and $wwwroot['scheme'] === 'https') {
 716             print_error('sslonlyaccess', 'error');
 717         }
 718     } else {
 719         if ($wwwroot['scheme'] !== 'https') {
 720             throw new coding_exception('Must use https address in wwwroot when ssl proxy enabled!');
 721         }
 722         $rurl['scheme'] = 'https'; // make moodle believe it runs on https, squid or something else it doing it
 723     }
 724
 725     // hopefully this will stop all those "clever" admins trying to set up moodle
 726     // with two different addresses in intranet and Internet
 727     if (!empty($CFG->reverseproxy) && $rurl['host'] === $wwwroot['host']) {
 728         print_error('reverseproxyabused', 'error');
 729     }
 730
 731     $hostandport = $rurl['scheme'] . '://' . $wwwroot['host'];
 732     if (!empty($wwwroot['port'])) {
 733         $hostandport .= ':'.$wwwroot['port'];
 734     }
 735
 736     $FULLSCRIPT = $hostandport . $rurl['path'];
 737     $FULLME = $hostandport . $rurl['fullpath'];
 738     $ME = $rurl['fullpath'];
 739 }
 740
 741 /**
 742  * Initialises $FULLME and friends for command line scripts.
 743  * This is a private method for use by initialise_fullme.
 744  */
 745 function initialise_fullme_cli() {
 746     global $CFG, $FULLME, $ME, $SCRIPT, $FULLSCRIPT;
 747
 748     // Urls do not make much sense in CLI scripts
 749     $backtrace = debug_backtrace();
 750     $topfile = array_pop($backtrace);
 751     $topfile = realpath($topfile['file']);
 752     $dirroot = realpath($CFG->dirroot);
 753
 754     if (strpos($topfile, $dirroot) !== 0) {
 755         // Probably some weird external script
 756         $SCRIPT = $FULLSCRIPT = $FULLME = $ME = null;
 757     } else {
 758         $relativefile = substr($topfile, strlen($dirroot));
 759         $relativefile = str_replace('\\', '/', $relativefile); // Win fix
 760         $SCRIPT = $FULLSCRIPT = $relativefile;
 761         $FULLME = $ME = null;
 762     }
 763 }
 764
 765 /**
 766  * Get the URL that PHP/the web server thinks it is serving. Private function
 767  * used by initialise_fullme. In your code, use $PAGE->url, $SCRIPT, etc.
 768  * @return array in the same format that parse_url returns, with the addition of
 769  *      a 'fullpath' element, which includes any slasharguments path.
 770  */
 771 function setup_get_remote_url() {
 772     $rurl = array();
 773     if (isset($_SERVER['HTTP_HOST'])) {
 774         list($rurl['host']) = explode(':', $_SERVER['HTTP_HOST']);
 775     } else {
 776         $rurl['host'] = null;
 777     }
 778     $rurl['port'] = $_SERVER['SERVER_PORT'];
 779     $rurl['path'] = $_SERVER['SCRIPT_NAME']; // Script path without slash arguments
 780     $rurl['scheme'] = (empty($_SERVER['HTTPS']) or $_SERVER['HTTPS'] === 'off' or $_SERVER['HTTPS'] === 'Off' or $_SERVER['HTTPS'] === 'OFF') ? 'http' : 'https';
 781
 782     if (stripos($_SERVER['SERVER_SOFTWARE'], 'apache') !== false) {
 783         //Apache server
 784         $rurl['fullpath'] = $_SERVER['REQUEST_URI'];
 785
 786     } else if (stripos($_SERVER['SERVER_SOFTWARE'], 'iis') !== false) {
 787         //IIS - needs a lot of tweaking to make it work
 788         $rurl['fullpath'] = $_SERVER['SCRIPT_NAME'];
 789
 790         // NOTE: ignore PATH_INFO because it is incorrectly encoded using 8bit filesystem legacy encoding in IIS
 791         //       since 2.0 we rely on iis rewrite extenssion like Helicon ISAPI_rewrite
 792         //       example rule: RewriteRule ^([^\?]+?\.php)(\/.+)$ $1\?file=$2 [QSA]
 793
 794         if ($_SERVER['QUERY_STRING'] != '') {
 795             $rurl['fullpath'] .= '?'.$_SERVER['QUERY_STRING'];
 796         }
 797         $_SERVER['REQUEST_URI'] = $rurl['fullpath']; // extra IIS compatibility
 798
 799 /* NOTE: following servers are not fully tested! */
 800
 801     } else if (stripos($_SERVER['SERVER_SOFTWARE'], 'lighttpd') !== false) {
 802         //lighttpd - not officially supported
 803         $rurl['fullpath'] = $_SERVER['REQUEST_URI']; // TODO: verify this is always properly encoded
 804
 805     } else if (stripos($_SERVER['SERVER_SOFTWARE'], 'nginx') !== false) {
 806         //nginx - not officially supported
 807         if (!isset($_SERVER['SCRIPT_NAME'])) {
 808             die('Invalid server configuration detected, please try to add "fastcgi_param SCRIPT_NAME $fastcgi_script_name;" to the nginx server configuration.');
 809         }
 810         $rurl['fullpath'] = $_SERVER['REQUEST_URI']; // TODO: verify this is always properly encoded
 811
 812      } else if (stripos($_SERVER['SERVER_SOFTWARE'], 'cherokee') !== false) {
 813          //cherokee - not officially supported
 814          $rurl['fullpath'] = $_SERVER['REQUEST_URI']; // TODO: verify this is always properly encoded
 815
 816      } else if (stripos($_SERVER['SERVER_SOFTWARE'], 'zeus') !== false) {
 817          //zeus - not officially supported
 818          $rurl['fullpath'] = $_SERVER['REQUEST_URI']; // TODO: verify this is always properly encoded
 819
 820     } else if (stripos($_SERVER['SERVER_SOFTWARE'], 'LiteSpeed') !== false) {
 821         //LiteSpeed - not officially supported
 822         $rurl['fullpath'] = $_SERVER['REQUEST_URI']; // TODO: verify this is always properly encoded
 823
 824     } else if ($_SERVER['SERVER_SOFTWARE'] === 'HTTPD') {
 825         //obscure name found on some servers - this is definitely not supported
 826         $rurl['fullpath'] = $_SERVER['REQUEST_URI']; // TODO: verify this is always properly encoded
 827
 828      } else {
 829         throw new moodle_exception('unsupportedwebserver', 'error', '', $_SERVER['SERVER_SOFTWARE']);
 830     }
 831
 832     // sanitize the url a bit more, the encoding style may be different in vars above
 833     $rurl['fullpath'] = str_replace('"', '%22', $rurl['fullpath']);
 834     $rurl['fullpath'] = str_replace('\'', '%27', $rurl['fullpath']);
 835
 836     return $rurl;
 837 }
 838
 839 /**
 840  * Initializes our performance info early.
 841  *
 842  * Pairs up with get_performance_info() which is actually
 843  * in moodlelib.php. This function is here so that we can
 844  * call it before all the libs are pulled in.
 845  *
 846  * @uses $PERF
 847  */
 848 function init_performance_info() {
 849
 850     global $PERF, $CFG, $USER;
 851
 852     $PERF = new stdClass();
 853     $PERF->logwrites = 0;
 854     if (function_exists('microtime')) {
 855         $PERF->starttime = microtime();
 856     }
 857     if (function_exists('memory_get_usage')) {
 858         $PERF->startmemory = memory_get_usage();
 859     }
 860     if (function_exists('posix_times')) {
 861         $PERF->startposixtimes = posix_times();
 862     }
 863 }
 864
 865 /**
 866  * Indicates whether we are in the middle of the initial Moodle install.
 867  *
 868  * Very occasionally it is necessary avoid running certain bits of code before the
 869  * Moodle installation has completed. The installed flag is set in admin/index.php
 870  * after Moodle core and all the plugins have been installed, but just before
 871  * the person doing the initial install is asked to choose the admin password.
 872  *
 873  * @return boolean true if the initial install is not complete.
 874  */
 875 function during_initial_install() {
 876     global $CFG;
 877     return empty($CFG->rolesactive);
 878 }
 879
 880 /**
 881  * Function to raise the memory limit to a new value.
 882  * Will respect the memory limit if it is higher, thus allowing
 883  * settings in php.ini, apache conf or command line switches
 884  * to override it.
 885  *
 886  * The memory limit should be expressed with a constant
 887  * MEMORY_STANDARD, MEMORY_EXTRA or MEMORY_HUGE.
 888  * It is possible to use strings or integers too (eg:'128M').
 889  *
 890  * @param mixed $newlimit the new memory limit
 891  * @return bool success
 892  */
 893 function raise_memory_limit($newlimit) {
 894     global $CFG;
 895
 896     if ($newlimit == MEMORY_UNLIMITED) {
 897         ini_set('memory_limit', -1);
 898         return true;
 899
 900     } else if ($newlimit == MEMORY_STANDARD) {
 901         if (PHP_INT_SIZE > 4) {
 902             $newlimit = get_real_size('128M'); // 64bit needs more memory
 903         } else {
 904             $newlimit = get_real_size('96M');
 905         }
 906
 907     } else if ($newlimit == MEMORY_EXTRA) {
 908         if (PHP_INT_SIZE > 4) {
 909             $newlimit = get_real_size('384M'); // 64bit needs more memory
 910         } else {
 911             $newlimit = get_real_size('256M');
 912         }
 913         if (!empty($CFG->extramemorylimit)) {
 914             $extra = get_real_size($CFG->extramemorylimit);
 915             if ($extra > $newlimit) {
 916                 $newlimit = $extra;
 917             }
 918         }
 919
 920     } else if ($newlimit == MEMORY_HUGE) {
 921         $newlimit = get_real_size('2G');
 922
 923     } else {
 924         $newlimit = get_real_size($newlimit);
 925     }
 926
 927     if ($newlimit <= 0) {
 928         debugging('Invalid memory limit specified.');
 929         return false;
 930     }
 931
 932     $cur = ini_get('memory_limit');
 933     if (empty($cur)) {
 934         // if php is compiled without --enable-memory-limits
 935         // apparently memory_limit is set to ''
 936         $cur = 0;
 937     } else {
 938         if ($cur == -1){
 939             return true; // unlimited mem!
 940         }
 941         $cur = get_real_size($cur);
 942     }
 943
 944     if ($newlimit > $cur) {
 945         ini_set('memory_limit', $newlimit);
 946         return true;
 947     }
 948     return false;
 949 }
 950
 951 /**
 952  * Function to reduce the memory limit to a new value.
 953  * Will respect the memory limit if it is lower, thus allowing
 954  * settings in php.ini, apache conf or command line switches
 955  * to override it
 956  *
 957  * The memory limit should be expressed with a string (eg:'64M')
 958  *
 959  * @param string $newlimit the new memory limit
 960  * @return bool
 961  */
 962 function reduce_memory_limit($newlimit) {
 963     if (empty($newlimit)) {
 964         return false;
 965     }
 966     $cur = ini_get('memory_limit');
 967     if (empty($cur)) {
 968         // if php is compiled without --enable-memory-limits
 969         // apparently memory_limit is set to ''
 970         $cur = 0;
 971     } else {
 972         if ($cur == -1){
 973             return true; // unlimited mem!
 974         }
 975         $cur = get_real_size($cur);
 976     }
 977
 978     $new = get_real_size($newlimit);
 979     // -1 is smaller, but it means unlimited
 980     if ($new < $cur && $new != -1) {
 981         ini_set('memory_limit', $newlimit);
 982         return true;
 983     }
 984     return false;
 985 }
 986
 987 /**
 988  * Converts numbers like 10M into bytes.
 989  *
 990  * @param string $size The size to be converted
 991  * @return int
 992  */
 993 function get_real_size($size = 0) {
 994     if (!$size) {
 995         return 0;
 996     }
 997     $scan = array();
 998     $scan['GB'] = 1073741824;
 999     $scan['Gb'] = 1073741824;
1000     $scan['G'] = 1073741824;
1001     $scan['MB'] = 1048576;
1002     $scan['Mb'] = 1048576;
1003     $scan['M'] = 1048576;
1004     $scan['m'] = 1048576;
1005     $scan['KB'] = 1024;
1006     $scan['Kb'] = 1024;
1007     $scan['K'] = 1024;
1008     $scan['k'] = 1024;
1009
1010     while (list($key) = each($scan)) {
1011         if ((strlen($size)>strlen($key))&&(substr($size, strlen($size) - strlen($key))==$key)) {
1012             $size = substr($size, 0, strlen($size) - strlen($key)) * $scan[$key];
1013             break;
1014         }
1015     }
1016     return $size;
1017 }
1018
1019 /**
1020  * Try to disable all output buffering and purge
1021  * all headers.
1022  *
1023  * @private to be called only from lib/setup.php !
1024  * @return void
1025  */
1026 function disable_output_buffering() {
1027     $olddebug = error_reporting(0);
1028
1029     // disable compression, it would prevent closing of buffers
1030     if (ini_get_bool('zlib.output_compression')) {
1031         ini_set('zlib.output_compression', 'Off');
1032     }
1033
1034     // try to flush everything all the time
1035     ob_implicit_flush(true);
1036
1037     // close all buffers if possible and discard any existing output
1038     // this can actually work around some whitespace problems in config.php
1039     while(ob_get_level()) {
1040         if (!ob_end_clean()) {
1041             // prevent infinite loop when buffer can not be closed
1042             break;
1043         }
1044     }
1045
1046     error_reporting($olddebug);
1047 }
1048
1049 /**
1050  * Check whether a major upgrade is needed. That is defined as an upgrade that
1051  * changes something really fundamental in the database, so nothing can possibly
1052  * work until the database has been updated, and that is defined by the hard-coded
1053  * version number in this function.
1054  */
1055 function redirect_if_major_upgrade_required() {
1056     global $CFG;
1057     $lastmajordbchanges = 2010111700;
1058     if (empty($CFG->version) or (int)$CFG->version < $lastmajordbchanges or
1059             during_initial_install() or !empty($CFG->adminsetuppending)) {
1060         try {
1061             @session_get_instance()->terminate_current();
1062         } catch (Exception $e) {
1063             // Ignore any errors, redirect to upgrade anyway.
1064         }
1065         $url = $CFG->wwwroot . '/' . $CFG->admin . '/index.php';
1066         @header($_SERVER['SERVER_PROTOCOL'] . ' 303 See Other');
1067         @header('Location: ' . $url);
1068         echo bootstrap_renderer::plain_redirect_message(htmlspecialchars($url));
1069         exit;
1070     }
1071 }
1072
1073 /**
1074  * Function to check if a directory exists and by default create it if not exists.
1075  *
1076  * Previously this was accepting paths only from dataroot, but we now allow
1077  * files outside of dataroot if you supply custom paths for some settings in config.php.
1078  * This function does not verify that the directory is writable.
1079  *
1080  * NOTE: this function uses current file stat cache,
1081  *       please use clearstatcache() before this if you expect that the
1082  *       directories may have been removed recently from a different request.
1083  *
1084  * @param string $dir absolute directory path
1085  * @param boolean $create directory if does not exist
1086  * @param boolean $recursive create directory recursively
1087  * @return boolean true if directory exists or created, false otherwise
1088  */
1089 function check_dir_exists($dir, $create = true, $recursive = true) {
1090     global $CFG;
1091
1092     umask(0000); // just in case some evil code changed it
1093
1094     if (is_dir($dir)) {
1095         return true;
1096     }
1097
1098     if (!$create) {
1099         return false;
1100     }
1101
1102     return mkdir($dir, $CFG->directorypermissions, $recursive);
1103 }
1104
1105 /**
1106  * Create a directory and make sure it is writable.
1107  *
1108  * @private
1109  * @param string $dir  the full path of the directory to be created
1110  * @param bool $exceptiononerror throw exception if error encountered
1111  * @return string|false Returns full path to directory if successful, false if not; may throw exception
1112  */
1113 function make_writable_directory($dir, $exceptiononerror = true) {
1114     global $CFG;
1115
1116     if (file_exists($dir) and !is_dir($dir)) {
1117         if ($exceptiononerror) {
1118             throw new coding_exception($dir.' directory can not be created, file with the same name already exists.');
1119         } else {
1120             return false;
1121         }
1122     }
1123
1124     umask(0000); // just in case some evil code changed it
1125
1126     if (!file_exists($dir)) {
1127         if (!mkdir($dir, $CFG->directorypermissions, true)) {
1128             if ($exceptiononerror) {
1129                 throw new invalid_dataroot_permissions($dir.' can not be created, check permissions.');
1130             } else {
1131                 return false;
1132             }
1133         }
1134     }
1135
1136     if (!is_writable($dir)) {
1137         if ($exceptiononerror) {
1138             throw new invalid_dataroot_permissions($dir.' is not writable, check permissions.');
1139         } else {
1140             return false;
1141         }
1142     }
1143
1144     return $dir;
1145 }
1146
1147 /**
1148  * Protect a directory from web access.
1149  * Could be extended in the future to support other mechanisms (e.g. other webservers).
1150  *
1151  * @private
1152  * @param string $dir  the full path of the directory to be protected
1153  */
1154 function protect_directory($dir) {
1155     // Make sure a .htaccess file is here, JUST IN CASE the files area is in the open and .htaccess is supported
1156     if (!file_exists("$dir/.htaccess")) {
1157         if ($handle = fopen("$dir/.htaccess", 'w')) {   // For safety
1158             @fwrite($handle, "deny from all\r\nAllowOverride None\r\nNote: this file is broken intentionally, we do not want anybody to undo it in subdirectory!\r\n");
1159             @fclose($handle);
1160         }
1161     }
1162 }
1163
1164 /**
1165  * Create a directory under dataroot and make sure it is writable.
1166  * Do not use for temporary and cache files - see make_temp_directory() and make_cache_directory().
1167  *
1168  * @param string $directory  the full path of the directory to be created under $CFG->dataroot
1169  * @param bool $exceptiononerror throw exception if error encountered
1170  * @return string|false Returns full path to directory if successful, false if not; may throw exception
1171  */
1172 function make_upload_directory($directory, $exceptiononerror = true) {
1173     global $CFG;
1174
1175     if (strpos($directory, 'temp/') === 0 or $directory === 'temp') {
1176         debugging('Use make_temp_directory() for creation of temporary directory and $CFG->tempdir to get the location.');
1177
1178     } else if (strpos($directory, 'cache/') === 0 or $directory === 'cache') {
1179         debugging('Use make_cache_directory() for creation of chache directory and $CFG->cachedir to get the location.');
1180     }
1181
1182     protect_directory($CFG->dataroot);
1183     return make_writable_directory("$CFG->dataroot/$directory", $exceptiononerror);
1184 }
1185
1186 /**
1187  * Create a directory under tempdir and make sure it is writable.
1188  * Temporary files should be used during the current request only!
1189  *
1190  * @param string $directory  the full path of the directory to be created under $CFG->tempdir
1191  * @param bool $exceptiononerror throw exception if error encountered
1192  * @return string|false Returns full path to directory if successful, false if not; may throw exception
1193  */
1194 function make_temp_directory($directory, $exceptiononerror = true) {
1195     global $CFG;
1196     if ($CFG->tempdir !== "$CFG->dataroot/temp") {
1197         check_dir_exists($CFG->tempdir, true, true);
1198         protect_directory($CFG->tempdir);
1199     } else {
1200         protect_directory($CFG->dataroot);
1201     }
1202     return make_writable_directory("$CFG->tempdir/$directory", $exceptiononerror);
1203 }
1204
1205 /**
1206  * Create a directory under cachedir and make sure it is writable.
1207  *
1208  * @param string $directory  the full path of the directory to be created under $CFG->cachedir
1209  * @param bool $exceptiononerror throw exception if error encountered
1210  * @return string|false Returns full path to directory if successful, false if not; may throw exception
1211  */
1212 function make_cache_directory($directory, $exceptiononerror = true) {
1213     global $CFG;
1214     if ($CFG->cachedir !== "$CFG->dataroot/cache") {
1215         check_dir_exists($CFG->cachedir, true, true);
1216         protect_directory($CFG->cachedir);
1217     } else {
1218         protect_directory($CFG->dataroot);
1219     }
1220     return make_writable_directory("$CFG->cachedir/$directory", $exceptiononerror);
1221 }
1222
1223
1224 function init_memcached() {
1225     global $CFG, $MCACHE;
1226
1227     include_once($CFG->libdir . '/memcached.class.php');
1228     $MCACHE = new memcached;
1229     if ($MCACHE->status()) {
1230         return true;
1231     }
1232     unset($MCACHE);
1233     return false;
1234 }
1235
1236 function init_eaccelerator() {
1237     global $CFG, $MCACHE;
1238
1239     include_once($CFG->libdir . '/eaccelerator.class.php');
1240     $MCACHE = new eaccelerator;
1241     if ($MCACHE->status()) {
1242         return true;
1243     }
1244     unset($MCACHE);
1245     return false;
1246 }
1247
1248 /**
1249  * Checks if current user is a web crawler.
1250  *
1251  * This list can not be made complete, this is not a security
1252  * restriction, we make the list only to help these sites
1253  * especially when automatic guest login is disabled.
1254  *
1255  * If admin needs security they should enable forcelogin
1256  * and disable guest access!!
1257  *
1258  * @return bool
1259  */
1260 function is_web_crawler() {
1261     if (!empty($_SERVER['HTTP_USER_AGENT'])) {
1262         if (strpos($_SERVER['HTTP_USER_AGENT'], 'Googlebot') !== false ) {
1263             return true;
1264         } else if (strpos($_SERVER['HTTP_USER_AGENT'], 'google.com') !== false ) { // Google
1265             return true;
1266         } else if (strpos($_SERVER['HTTP_USER_AGENT'], 'Yahoo! Slurp') !== false ) {  // Yahoo
1267             return true;
1268         } else if (strpos($_SERVER['HTTP_USER_AGENT'], '[ZSEBOT]') !== false ) {  // Zoomspider
1269             return true;
1270         } else if (strpos($_SERVER['HTTP_USER_AGENT'], 'MSNBOT') !== false ) {  // MSN Search
1271             return true;
1272         } else if (strpos($_SERVER['HTTP_USER_AGENT'], 'Yandex') !== false ) {
1273             return true;
1274         } else if (strpos($_SERVER['HTTP_USER_AGENT'], 'AltaVista') !== false ) {
1275             return true;
1276         }
1277     }
1278     return false;
1279 }
1280
1281 /**
1282  * This class solves the problem of how to initialise $OUTPUT.
1283  *
1284  * The problem is caused be two factors
1285  * <ol>
1286  * <li>On the one hand, we cannot be sure when output will start. In particular,
1287  * an error, which needs to be displayed, could be thrown at any time.</li>
1288  * <li>On the other hand, we cannot be sure when we will have all the information
1289  * necessary to correctly initialise $OUTPUT. $OUTPUT depends on the theme, which
1290  * (potentially) depends on the current course, course categories, and logged in user.
1291  * It also depends on whether the current page requires HTTPS.</li>
1292  * </ol>
1293  *
1294  * So, it is hard to find a single natural place during Moodle script execution,
1295  * which we can guarantee is the right time to initialise $OUTPUT. Instead we
1296  * adopt the following strategy
1297  * <ol>
1298  * <li>We will initialise $OUTPUT the first time it is used.</li>
1299  * <li>If, after $OUTPUT has been initialised, the script tries to change something
1300  * that $OUTPUT depends on, we throw an exception making it clear that the script
1301  * did something wrong.
1302  * </ol>
1303  *
1304  * The only problem with that is, how do we initialise $OUTPUT on first use if,
1305  * it is going to be used like $OUTPUT->somthing(...)? Well that is where this
1306  * class comes in. Initially, we set up $OUTPUT = new bootstrap_renderer(). Then,
1307  * when any method is called on that object, we initialise $OUTPUT, and pass the call on.
1308  *
1309  * Note that this class is used before lib/outputlib.php has been loaded, so we
1310  * must be careful referring to classes/functions from there, they may not be
1311  * defined yet, and we must avoid fatal errors.
1312  *
1313  * @copyright 2009 Tim Hunt
1314  * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
1315  * @since     Moodle 2.0
1316  */
1317 class bootstrap_renderer {
1318     /**
1319      * Handles re-entrancy. Without this, errors or debugging output that occur
1320      * during the initialisation of $OUTPUT, cause infinite recursion.
1321      * @var boolean
1322      */
1323     protected $initialising = false;
1324
1325     /**
1326      * Have we started output yet?
1327      * @return boolean true if the header has been printed.
1328      */
1329     public function has_started() {
1330         return false;
1331     }
1332
1333     /**
1334      * Constructor - to be used by core code only.
1335      * @param $method
1336      * @param $arguments
1337      * @return string
1338      */
1339     public function __call($method, $arguments) {
1340         global $OUTPUT, $PAGE;
1341
1342         $recursing = false;
1343         if ($method == 'notification') {
1344             // Catch infinite recursion caused by debugging output during print_header.
1345             $backtrace = debug_backtrace();
1346             array_shift($backtrace);
1347             array_shift($backtrace);
1348             $recursing = is_early_init($backtrace);
1349         }
1350
1351         $earlymethods = array(
1352             'fatal_error' => 'early_error',
1353             'notification' => 'early_notification',
1354         );
1355
1356         // If lib/outputlib.php has been loaded, call it.
1357         if (!empty($PAGE) && !$recursing) {
1358             if (array_key_exists($method, $earlymethods)) {
1359                 //prevent PAGE->context warnings - exceptions might appear before we set any context
1360                 $PAGE->set_context(null);
1361             }
1362             $PAGE->initialise_theme_and_output();
1363             return call_user_func_array(array($OUTPUT, $method), $arguments);
1364         }
1365
1366         $this->initialising = true;
1367
1368         // Too soon to initialise $OUTPUT, provide a couple of key methods.
1369         if (array_key_exists($method, $earlymethods)) {
1370             return call_user_func_array(array('bootstrap_renderer', $earlymethods[$method]), $arguments);
1371         }
1372
1373         throw new coding_exception('Attempt to start output before enough information is known to initialise the theme.');
1374     }
1375
1376     /**
1377      * Returns nicely formatted error message in a div box.
1378      * @static
1379      * @param string $message error message
1380      * @param string $moreinfourl (ignored in early errors)
1381      * @param string $link (ignored in early errors)
1382      * @param array $backtrace
1383      * @param string $debuginfo
1384      * @return string
1385      */
1386     public static function early_error_content($message, $moreinfourl, $link, $backtrace, $debuginfo = null) {
1387         global $CFG;
1388
1389         $content = '<div style="margin-top: 6em; margin-left:auto; margin-right:auto; color:#990000; text-align:center; font-size:large; border-width:1px;
1390 border-color:black; background-color:#ffffee; border-style:solid; border-radius: 20px; border-collapse: collapse;
1391 width: 80%; -moz-border-radius: 20px; padding: 15px">
1392 ' . $message . '
1393 </div>';
1394         if (!empty($CFG->debug) && $CFG->debug >= DEBUG_DEVELOPER) {
1395             if (!empty($debuginfo)) {
1396                 $debuginfo = s($debuginfo); // removes all nasty JS
1397                 $debuginfo = str_replace("\n", '<br />', $debuginfo); // keep newlines
1398                 $content .= '<div class="notifytiny">Debug info: ' . $debuginfo . '</div>';
1399             }
1400             if (!empty($backtrace)) {
1401                 $content .= '<div class="notifytiny">Stack trace: ' . format_backtrace($backtrace, false) . '</div>';
1402             }
1403         }
1404
1405         return $content;
1406     }
1407
1408     /**
1409      * This function should only be called by this class, or from exception handlers
1410      * @static
1411      * @param string $message error message
1412      * @param string $moreinfourl (ignored in early errors)
1413      * @param string $link (ignored in early errors)
1414      * @param array $backtrace
1415      * @param string $debuginfo extra information for developers
1416      * @return string
1417      */
1418     public static function early_error($message, $moreinfourl, $link, $backtrace, $debuginfo = null) {
1419         global $CFG;
1420
1421         if (CLI_SCRIPT) {
1422             echo "!!! $message !!!\n";
1423             if (!empty($CFG->debug) and $CFG->debug >= DEBUG_DEVELOPER) {
1424                 if (!empty($debuginfo)) {
1425                     echo "\nDebug info: $debuginfo";
1426                 }
1427                 if (!empty($backtrace)) {
1428                     echo "\nStack trace: " . format_backtrace($backtrace, true);
1429                 }
1430             }
1431             return;
1432
1433         } else if (AJAX_SCRIPT) {
1434             $e = new stdClass();
1435             $e->error      = $message;
1436             $e->stacktrace = NULL;
1437             $e->debuginfo  = NULL;
1438             if (!empty($CFG->debug) and $CFG->debug >= DEBUG_DEVELOPER) {
1439                 if (!empty($debuginfo)) {
1440                     $e->debuginfo = $debuginfo;
1441                 }
1442                 if (!empty($backtrace)) {
1443                     $e->stacktrace = format_backtrace($backtrace, true);
1444                 }
1445             }
1446             @header('Content-Type: application/json; charset=utf-8');
1447             echo json_encode($e);
1448             return;
1449         }
1450
1451         // In the name of protocol correctness, monitoring and performance
1452         // profiling, set the appropriate error headers for machine consumption
1453         if (isset($_SERVER['SERVER_PROTOCOL'])) {
1454             // Avoid it with cron.php. Note that we assume it's HTTP/1.x
1455             // The 503 ode here means our Moodle does not work at all, the error happened too early
1456             @header($_SERVER['SERVER_PROTOCOL'] . ' 503 Service Unavailable');
1457         }
1458
1459         // better disable any caching
1460         @header('Content-Type: text/html; charset=utf-8');
1461         @header('Cache-Control: no-store, no-cache, must-revalidate');
1462         @header('Cache-Control: post-check=0, pre-check=0', false);
1463         @header('Pragma: no-cache');
1464         @header('Expires: Mon, 20 Aug 1969 09:23:00 GMT');
1465         @header('Last-Modified: ' . gmdate('D, d M Y H:i:s') . ' GMT');
1466
1467         if (function_exists('get_string')) {
1468             $strerror = get_string('error');
1469         } else {
1470             $strerror = 'Error';
1471         }
1472
1473         $content = self::early_error_content($message, $moreinfourl, $link, $backtrace, $debuginfo);
1474
1475         return self::plain_page($strerror, $content);
1476     }
1477
1478     /**
1479      * Early notification message
1480      * @static
1481      * @param $message
1482      * @param string $classes usually notifyproblem or notifysuccess
1483      * @return string
1484      */
1485     public static function early_notification($message, $classes = 'notifyproblem') {
1486         return '<div class="' . $classes . '">' . $message . '</div>';
1487     }
1488
1489     /**
1490      * Page should redirect message.
1491      * @static
1492      * @param $encodedurl redirect url
1493      * @return string
1494      */
1495     public static function plain_redirect_message($encodedurl) {
1496         $message = '<div style="margin-top: 3em; margin-left:auto; margin-right:auto; text-align:center;">' . get_string('pageshouldredirect') . '<br /><a href="'.
1497                 $encodedurl .'">'. get_string('continue') .'</a></div>';
1498         return self::plain_page(get_string('redirect'), $message);
1499     }
1500
1501     /**
1502      * Early redirection page, used before full init of $PAGE global
1503      * @static
1504      * @param $encodedurl redirect url
1505      * @param $message redirect message
1506      * @param $delay time in seconds
1507      * @return string redirect page
1508      */
1509     public static function early_redirect_message($encodedurl, $message, $delay) {
1510         $meta = '<meta http-equiv="refresh" content="'. $delay .'; url='. $encodedurl .'" />';
1511         $content = self::early_error_content($message, null, null, null);
1512         $content .= self::plain_redirect_message($encodedurl);
1513
1514         return self::plain_page(get_string('redirect'), $content, $meta);
1515     }
1516
1517     /**
1518      * Output basic html page.
1519      * @static
1520      * @param $title page title
1521      * @param $content page content
1522      * @param string $meta meta tag
1523      * @return string html page
1524      */
1525     protected static function plain_page($title, $content, $meta = '') {
1526         if (function_exists('get_string') && function_exists('get_html_lang')) {
1527             $htmllang = get_html_lang();
1528         } else {
1529             $htmllang = '';
1530         }
1531
1532         return '<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
1533 <html xmlns="http://www.w3.org/1999/xhtml" ' . $htmllang . '>
1534 <head>
1535 <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
1536 '.$meta.'
1537 <title>' . $title . '</title>
1538 </head><body>' . $content . '</body></html>';
1539     }
1540 }