lib/setuplib.php

   1 <?php
   2 // This file is part of Moodle - http://moodle.org/
   3 //
   4 // Moodle is free software: you can redistribute it and/or modify
   5 // it under the terms of the GNU General Public License as published by
   6 // the Free Software Foundation, either version 3 of the License, or
   7 // (at your option) any later version.
   8 //
   9 // Moodle is distributed in the hope that it will be useful,
  10 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 // GNU General Public License for more details.
  13 //
  14 // You should have received a copy of the GNU General Public License
  15 // along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
  16
  17 /**
  18  * These functions are required very early in the Moodle
  19  * setup process, before any of the main libraries are
  20  * loaded.
  21  *
  22  * @package    core
  23  * @subpackage lib
  24  * @copyright  1999 onwards Martin Dougiamas  {@link http://moodle.com}
  25  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  26  */
  27
  28 defined('MOODLE_INTERNAL') || die();
  29
  30 // Debug levels - always keep the values in ascending order!
  31 /** No warnings and errors at all */
  32 define('DEBUG_NONE', 0);
  33 /** Fatal errors only */
  34 define('DEBUG_MINIMAL', E_ERROR | E_PARSE);
  35 /** Errors, warnings and notices */
  36 define('DEBUG_NORMAL', E_ERROR | E_PARSE | E_WARNING | E_NOTICE);
  37 /** All problems except strict PHP warnings */
  38 define('DEBUG_ALL', E_ALL & ~E_STRICT);
  39 /** DEBUG_ALL with all debug messages and strict warnings */
  40 define('DEBUG_DEVELOPER', E_ALL | E_STRICT);
  41
  42 /** Remove any memory limits */
  43 define('MEMORY_UNLIMITED', -1);
  44 /** Standard memory limit for given platform */
  45 define('MEMORY_STANDARD', -2);
  46 /**
  47  * Large memory limit for given platform - used in cron, upgrade, and other places that need a lot of memory.
  48  * Can be overridden with $CFG->extramemorylimit setting.
  49  */
  50 define('MEMORY_EXTRA', -3);
  51 /** Extremely large memory limit - not recommended for standard scripts */
  52 define('MEMORY_HUGE', -4);
  53
  54 /**
  55  * Software maturity levels used by the core and plugins
  56  */
  57 define('MATURITY_ALPHA',    50);    // internals can be tested using white box techniques
  58 define('MATURITY_BETA',     100);   // feature complete, ready for preview and testing
  59 define('MATURITY_RC',       150);   // tested, will be released unless there are fatal bugs
  60 define('MATURITY_STABLE',   200);   // ready for production deployment
  61
  62 /**
  63  * Special value that can be used in $plugin->dependencies in version.php files.
  64  */
  65 define('ANY_VERSION', 'any');
  66
  67
  68 /**
  69  * Simple class. It is usually used instead of stdClass because it looks
  70  * more familiar to Java developers ;-) Do not use for type checking of
  71  * function parameters. Please use stdClass instead.
  72  *
  73  * @package    core
  74  * @subpackage lib
  75  * @copyright  2009 Petr Skoda  {@link http://skodak.org}
  76  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  77  * @deprecated since 2.0
  78  */
  79 class object extends stdClass {};
  80
  81 /**
  82  * Base Moodle Exception class
  83  *
  84  * Although this class is defined here, you cannot throw a moodle_exception until
  85  * after moodlelib.php has been included (which will happen very soon).
  86  *
  87  * @package    core
  88  * @subpackage lib
  89  * @copyright  2008 Petr Skoda  {@link http://skodak.org}
  90  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  91  */
  92 class moodle_exception extends Exception {
  93
  94     /**
  95      * @var string The name of the string from error.php to print
  96      */
  97     public $errorcode;
  98
  99     /**
 100      * @var string The name of module
 101      */
 102     public $module;
 103
 104     /**
 105      * @var mixed Extra words and phrases that might be required in the error string
 106      */
 107     public $a;
 108
 109     /**
 110      * @var string 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.
 111      */
 112     public $link;
 113
 114     /**
 115      * @var string Optional information to aid the debugging process
 116      */
 117     public $debuginfo;
 118
 119     /**
 120      * Constructor
 121      * @param string $errorcode The name of the string from error.php to print
 122      * @param string $module name of module
 123      * @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.
 124      * @param mixed $a Extra words and phrases that might be required in the error string
 125      * @param string $debuginfo optional debugging information
 126      */
 127     function __construct($errorcode, $module='', $link='', $a=NULL, $debuginfo=null) {
 128         if (empty($module) || $module == 'moodle' || $module == 'core') {
 129             $module = 'error';
 130         }
 131
 132         $this->errorcode = $errorcode;
 133         $this->module    = $module;
 134         $this->link      = $link;
 135         $this->a         = $a;
 136         $this->debuginfo = is_null($debuginfo) ? null : (string)$debuginfo;
 137
 138         if (get_string_manager()->string_exists($errorcode, $module)) {
 139             $message = get_string($errorcode, $module, $a);
 140         } else {
 141             $message = $module . '/' . $errorcode;
 142         }
 143
 144         if (defined('PHPUNIT_TEST') and PHPUNIT_TEST and $debuginfo) {
 145             $message = "$message ($debuginfo)";
 146         }
 147
 148         parent::__construct($message, 0);
 149     }
 150 }
 151
 152 /**
 153  * Course/activity access exception.
 154  *
 155  * This exception is thrown from require_login()
 156  *
 157  * @package    core_access
 158  * @copyright  2010 Petr Skoda  {@link http://skodak.org}
 159  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 160  */
 161 class require_login_exception extends moodle_exception {
 162     /**
 163      * Constructor
 164      * @param string $debuginfo Information to aid the debugging process
 165      */
 166     function __construct($debuginfo) {
 167         parent::__construct('requireloginerror', 'error', '', NULL, $debuginfo);
 168     }
 169 }
 170
 171 /**
 172  * Web service parameter exception class
 173  * @deprecated since Moodle 2.2 - use moodle exception instead
 174  * This exception must be thrown to the web service client when a web service parameter is invalid
 175  * The error string is gotten from webservice.php
 176  */
 177 class webservice_parameter_exception extends moodle_exception {
 178     /**
 179      * Constructor
 180      * @param string $errorcode The name of the string from webservice.php to print
 181      * @param string $a The name of the parameter
 182      * @param string $debuginfo Optional information to aid debugging
 183      */
 184     function __construct($errorcode=null, $a = '', $debuginfo = null) {
 185         parent::__construct($errorcode, 'webservice', '', $a, $debuginfo);
 186     }
 187 }
 188
 189 /**
 190  * Exceptions indicating user does not have permissions to do something
 191  * and the execution can not continue.
 192  *
 193  * @package    core_access
 194  * @copyright  2009 Petr Skoda  {@link http://skodak.org}
 195  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 196  */
 197 class required_capability_exception extends moodle_exception {
 198     /**
 199      * Constructor
 200      * @param context $context The context used for the capability check
 201      * @param string $capability The required capability
 202      * @param string $errormessage The error message to show the user
 203      * @param string $stringfile
 204      */
 205     function __construct($context, $capability, $errormessage, $stringfile) {
 206         $capabilityname = get_capability_string($capability);
 207         if ($context->contextlevel == CONTEXT_MODULE and preg_match('/:view$/', $capability)) {
 208             // 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
 209             $paranetcontext = context::instance_by_id(get_parent_contextid($context));
 210             $link = get_context_url($paranetcontext);
 211         } else {
 212             $link = get_context_url($context);
 213         }
 214         parent::__construct($errormessage, $stringfile, $link, $capabilityname);
 215     }
 216 }
 217
 218 /**
 219  * Exception indicating programming error, must be fixed by a programer. For example
 220  * a core API might throw this type of exception if a plugin calls it incorrectly.
 221  *
 222  * @package    core
 223  * @subpackage lib
 224  * @copyright  2008 Petr Skoda  {@link http://skodak.org}
 225  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 226  */
 227 class coding_exception extends moodle_exception {
 228     /**
 229      * Constructor
 230      * @param string $hint short description of problem
 231      * @param string $debuginfo detailed information how to fix problem
 232      */
 233     function __construct($hint, $debuginfo=null) {
 234         parent::__construct('codingerror', 'debug', '', $hint, $debuginfo);
 235     }
 236 }
 237
 238 /**
 239  * Exception indicating malformed parameter problem.
 240  * This exception is not supposed to be thrown when processing
 241  * user submitted data in forms. It is more suitable
 242  * for WS and other low level stuff.
 243  *
 244  * @package    core
 245  * @subpackage lib
 246  * @copyright  2009 Petr Skoda  {@link http://skodak.org}
 247  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 248  */
 249 class invalid_parameter_exception extends moodle_exception {
 250     /**
 251      * Constructor
 252      * @param string $debuginfo some detailed information
 253      */
 254     function __construct($debuginfo=null) {
 255         parent::__construct('invalidparameter', 'debug', '', null, $debuginfo);
 256     }
 257 }
 258
 259 /**
 260  * Exception indicating malformed response problem.
 261  * This exception is not supposed to be thrown when processing
 262  * user submitted data in forms. It is more suitable
 263  * for WS and other low level stuff.
 264  */
 265 class invalid_response_exception extends moodle_exception {
 266     /**
 267      * Constructor
 268      * @param string $debuginfo some detailed information
 269      */
 270     function __construct($debuginfo=null) {
 271         parent::__construct('invalidresponse', 'debug', '', null, $debuginfo);
 272     }
 273 }
 274
 275 /**
 276  * An exception that indicates something really weird happened. For example,
 277  * if you do switch ($context->contextlevel), and have one case for each
 278  * CONTEXT_... constant. You might throw an invalid_state_exception in the
 279  * default case, to just in case something really weird is going on, and
 280  * $context->contextlevel is invalid - rather than ignoring this possibility.
 281  *
 282  * @package    core
 283  * @subpackage lib
 284  * @copyright  2009 onwards Martin Dougiamas  {@link http://moodle.com}
 285  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 286  */
 287 class invalid_state_exception extends moodle_exception {
 288     /**
 289      * Constructor
 290      * @param string $hint short description of problem
 291      * @param string $debuginfo optional more detailed information
 292      */
 293     function __construct($hint, $debuginfo=null) {
 294         parent::__construct('invalidstatedetected', 'debug', '', $hint, $debuginfo);
 295     }
 296 }
 297
 298 /**
 299  * An exception that indicates incorrect permissions in $CFG->dataroot
 300  *
 301  * @package    core
 302  * @subpackage lib
 303  * @copyright  2010 Petr Skoda {@link http://skodak.org}
 304  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 305  */
 306 class invalid_dataroot_permissions extends moodle_exception {
 307     /**
 308      * Constructor
 309      * @param string $debuginfo optional more detailed information
 310      */
 311     function __construct($debuginfo = NULL) {
 312         parent::__construct('invaliddatarootpermissions', 'error', '', NULL, $debuginfo);
 313     }
 314 }
 315
 316 /**
 317  * An exception that indicates that file can not be served
 318  *
 319  * @package    core
 320  * @subpackage lib
 321  * @copyright  2010 Petr Skoda {@link http://skodak.org}
 322  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 323  */
 324 class file_serving_exception extends moodle_exception {
 325     /**
 326      * Constructor
 327      * @param string $debuginfo optional more detailed information
 328      */
 329     function __construct($debuginfo = NULL) {
 330         parent::__construct('cannotservefile', 'error', '', NULL, $debuginfo);
 331     }
 332 }
 333
 334 /**
 335  * Default exception handler, uncaught exceptions are equivalent to error() in 1.9 and earlier
 336  *
 337  * @param Exception $ex
 338  * @return void -does not return. Terminates execution!
 339  */
 340 function default_exception_handler($ex) {
 341     global $CFG, $DB, $OUTPUT, $USER, $FULLME, $SESSION, $PAGE;
 342
 343     // detect active db transactions, rollback and log as error
 344     abort_all_db_transactions();
 345
 346     if (($ex instanceof required_capability_exception) && !CLI_SCRIPT && !AJAX_SCRIPT && !empty($CFG->autologinguests) && !empty($USER->autologinguest)) {
 347         $SESSION->wantsurl = qualified_me();
 348         redirect(get_login_url());
 349     }
 350
 351     $info = get_exception_info($ex);
 352
 353     if (debugging('', DEBUG_MINIMAL)) {
 354         $logerrmsg = "Default exception handler: ".$info->message.' Debug: '.$info->debuginfo."\n".format_backtrace($info->backtrace, true);
 355         error_log($logerrmsg);
 356     }
 357
 358     if (is_early_init($info->backtrace)) {
 359         echo bootstrap_renderer::early_error($info->message, $info->moreinfourl, $info->link, $info->backtrace, $info->debuginfo);
 360     } else {
 361         try {
 362             if ($DB) {
 363                 // If you enable db debugging and exception is thrown, the print footer prints a lot of rubbish
 364                 $DB->set_debug(0);
 365             }
 366             echo $OUTPUT->fatal_error($info->message, $info->moreinfourl, $info->link, $info->backtrace, $info->debuginfo);
 367         } catch (Exception $out_ex) {
 368             // default exception handler MUST not throw any exceptions!!
 369             // the problem here is we do not know if page already started or not, we only know that somebody messed up in outputlib or theme
 370             // so we just print at least something instead of "Exception thrown without a stack frame in Unknown on line 0":-(
 371             if (CLI_SCRIPT or AJAX_SCRIPT) {
 372                 // just ignore the error and send something back using the safest method
 373                 echo bootstrap_renderer::early_error($info->message, $info->moreinfourl, $info->link, $info->backtrace, $info->debuginfo);
 374             } else {
 375                 echo bootstrap_renderer::early_error_content($info->message, $info->moreinfourl, $info->link, $info->backtrace, $info->debuginfo);
 376                 $outinfo = get_exception_info($out_ex);
 377                 echo bootstrap_renderer::early_error_content($outinfo->message, $outinfo->moreinfourl, $outinfo->link, $outinfo->backtrace, $outinfo->debuginfo);
 378             }
 379         }
 380     }
 381
 382     exit(1); // General error code
 383 }
 384
 385 /**
 386  * Default error handler, prevents some white screens.
 387  * @param int $errno
 388  * @param string $errstr
 389  * @param string $errfile
 390  * @param int $errline
 391  * @param array $errcontext
 392  * @return bool false means use default error handler
 393  */
 394 function default_error_handler($errno, $errstr, $errfile, $errline, $errcontext) {
 395     if ($errno == 4096) {
 396         //fatal catchable error
 397         throw new coding_exception('PHP catchable fatal error', $errstr);
 398     }
 399     return false;
 400 }
 401
 402 /**
 403  * Unconditionally abort all database transactions, this function
 404  * should be called from exception handlers only.
 405  * @return void
 406  */
 407 function abort_all_db_transactions() {
 408     global $CFG, $DB, $SCRIPT;
 409
 410     // default exception handler MUST not throw any exceptions!!
 411
 412     if ($DB && $DB->is_transaction_started()) {
 413         error_log('Database transaction aborted automatically in ' . $CFG->dirroot . $SCRIPT);
 414         // note: transaction blocks should never change current $_SESSION
 415         $DB->force_transaction_rollback();
 416     }
 417 }
 418
 419 /**
 420  * This function encapsulates the tests for whether an exception was thrown in
 421  * early init -- either during setup.php or during init of $OUTPUT.
 422  *
 423  * If another exception is thrown then, and if we do not take special measures,
 424  * we would just get a very cryptic message "Exception thrown without a stack
 425  * frame in Unknown on line 0". That makes debugging very hard, so we do take
 426  * special measures in default_exception_handler, with the help of this function.
 427  *
 428  * @param array $backtrace the stack trace to analyse.
 429  * @return boolean whether the stack trace is somewhere in output initialisation.
 430  */
 431 function is_early_init($backtrace) {
 432     $dangerouscode = array(
 433         array('function' => 'header', 'type' => '->'),
 434         array('class' => 'bootstrap_renderer'),
 435         array('file' => dirname(__FILE__).'/setup.php'),
 436     );
 437     foreach ($backtrace as $stackframe) {
 438         foreach ($dangerouscode as $pattern) {
 439             $matches = true;
 440             foreach ($pattern as $property => $value) {
 441                 if (!isset($stackframe[$property]) || $stackframe[$property] != $value) {
 442                     $matches = false;
 443                 }
 444             }
 445             if ($matches) {
 446                 return true;
 447             }
 448         }
 449     }
 450     return false;
 451 }
 452
 453 /**
 454  * Abort execution by throwing of a general exception,
 455  * default exception handler displays the error message in most cases.
 456  *
 457  * @param string $errorcode The name of the language string containing the error message.
 458  *      Normally this should be in the error.php lang file.
 459  * @param string $module The language file to get the error message from.
 460  * @param string $link The url where the user will be prompted to continue.
 461  *      If no url is provided the user will be directed to the site index page.
 462  * @param object $a Extra words and phrases that might be required in the error string
 463  * @param string $debuginfo optional debugging information
 464  * @return void, always throws exception!
 465  */
 466 function print_error($errorcode, $module = 'error', $link = '', $a = null, $debuginfo = null) {
 467     throw new moodle_exception($errorcode, $module, $link, $a, $debuginfo);
 468 }
 469
 470 /**
 471  * Returns detailed information about specified exception.
 472  * @param exception $ex
 473  * @return object
 474  */
 475 function get_exception_info($ex) {
 476     global $CFG, $DB, $SESSION;
 477
 478     if ($ex instanceof moodle_exception) {
 479         $errorcode = $ex->errorcode;
 480         $module = $ex->module;
 481         $a = $ex->a;
 482         $link = $ex->link;
 483         $debuginfo = $ex->debuginfo;
 484     } else {
 485         $errorcode = 'generalexceptionmessage';
 486         $module = 'error';
 487         $a = $ex->getMessage();
 488         $link = '';
 489         $debuginfo = '';
 490     }
 491
 492     // Append the error code to the debug info to make grepping and googling easier
 493     $debuginfo .= PHP_EOL."Error code: $errorcode";
 494
 495     $backtrace = $ex->getTrace();
 496     $place = array('file'=>$ex->getFile(), 'line'=>$ex->getLine(), 'exception'=>get_class($ex));
 497     array_unshift($backtrace, $place);
 498
 499     // Be careful, no guarantee moodlelib.php is loaded.
 500     if (empty($module) || $module == 'moodle' || $module == 'core') {
 501         $module = 'error';
 502     }
 503     // Search for the $errorcode's associated string
 504     // If not found, append the contents of $a to $debuginfo so helpful information isn't lost
 505     if (function_exists('get_string_manager')) {
 506         if (get_string_manager()->string_exists($errorcode, $module)) {
 507             $message = get_string($errorcode, $module, $a);
 508         } elseif ($module == 'error' && get_string_manager()->string_exists($errorcode, 'moodle')) {
 509             // Search in moodle file if error specified - needed for backwards compatibility
 510             $message = get_string($errorcode, 'moodle', $a);
 511         } else {
 512             $message = $module . '/' . $errorcode;
 513             $debuginfo .= PHP_EOL.'$a contents: '.print_r($a, true);
 514         }
 515     } else {
 516         $message = $module . '/' . $errorcode;
 517         $debuginfo .= PHP_EOL.'$a contents: '.print_r($a, true);
 518     }
 519
 520     // Be careful, no guarantee weblib.php is loaded.
 521     if (function_exists('clean_text')) {
 522         $message = clean_text($message);
 523     } else {
 524         $message = htmlspecialchars($message);
 525     }
 526
 527     if (!empty($CFG->errordocroot)) {
 528         $errordoclink = $CFG->errordocroot . '/en/';
 529     } else {
 530         $errordoclink = get_docs_url();
 531     }
 532
 533     if ($module === 'error') {
 534         $modulelink = 'moodle';
 535     } else {
 536         $modulelink = $module;
 537     }
 538     $moreinfourl = $errordoclink . 'error/' . $modulelink . '/' . $errorcode;
 539
 540     if (empty($link)) {
 541         if (!empty($SESSION->fromurl)) {
 542             $link = $SESSION->fromurl;
 543             unset($SESSION->fromurl);
 544         } else {
 545             $link = $CFG->wwwroot .'/';
 546         }
 547     }
 548
 549     // when printing an error the continue button should never link offsite
 550     if (stripos($link, $CFG->wwwroot) === false &&
 551         stripos($link, $CFG->httpswwwroot) === false) {
 552         $link = $CFG->wwwroot.'/';
 553     }
 554
 555     $info = new stdClass();
 556     $info->message     = $message;
 557     $info->errorcode   = $errorcode;
 558     $info->backtrace   = $backtrace;
 559     $info->link        = $link;
 560     $info->moreinfourl = $moreinfourl;
 561     $info->a           = $a;
 562     $info->debuginfo   = $debuginfo;
 563
 564     return $info;
 565 }
 566
 567 /**
 568  * Returns the Moodle Docs URL in the users language for a given 'More help' link.
 569  *
 570  * There are three cases:
 571  *
 572  * 1. In the normal case, $path will be a short relative path 'component/thing',
 573  * like 'mod/folder/view' 'group/import'. This gets turned into an link to
 574  * MoodleDocs in the user's language, and for the appropriate Moodle version.
 575  * E.g. 'group/import' may become 'http://docs.moodle.org/2x/en/group/import'.
 576  * The 'http://docs.moodle.org' bit comes from $CFG->docroot.
 577  *
 578  * This is the only option that should be used in standard Moodle code. The other
 579  * two options have been implemented because they are useful for third-party plugins.
 580  *
 581  * 2. $path may be an absolute URL, starting http:// or https://. In this case,
 582  * the link is used as is.
 583  *
 584  * 3. $path may start %%WWWROOT%%, in which case that is replaced by
 585  * $CFG->wwwroot to make the link.
 586  *
 587  * @param string $path the place to link to. See above for details.
 588  * @return string The MoodleDocs URL in the user's language. for example @link http://docs.moodle.org/2x/en/$path}
 589  */
 590 function get_docs_url($path = null) {
 591     global $CFG;
 592
 593     // Absolute URLs are used unmodified.
 594     if (substr($path, 0, 7) === 'http://' || substr($path, 0, 8) === 'https://') {
 595         return $path;
 596     }
 597
 598     // Paths starting %%WWWROOT%% have that replaced by $CFG->wwwroot.
 599     if (substr($path, 0, 11) === '%%WWWROOT%%') {
 600         return $CFG->wwwroot . substr($path, 11);
 601     }
 602
 603     // Otherwise we do the normal case, and construct a MoodleDocs URL relative to $CFG->docroot.
 604
 605     // Check that $CFG->branch has been set up, during installation it won't be.
 606     if (empty($CFG->branch)) {
 607         // It's not there yet so look at version.php.
 608         include($CFG->dirroot.'/version.php');
 609     } else {
 610         // We can use $CFG->branch and avoid having to include version.php.
 611         $branch = $CFG->branch;
 612     }
 613     // ensure branch is valid.
 614     if (!$branch) {
 615         // We should never get here but in case we do lets set $branch to .
 616         // the smart one's will know that this is the current directory
 617         // and the smarter ones will know that there is some smart matching
 618         // that will ensure people end up at the latest version of the docs.
 619         $branch = '.';
 620     }
 621     if (!empty($CFG->docroot)) {
 622         return $CFG->docroot . '/' . $branch . '/' . current_language() . '/' . $path;
 623     } else {
 624         return 'http://docs.moodle.org/'. $branch . '/' . current_language() . '/' . $path;
 625     }
 626 }
 627
 628 /**
 629  * Formats a backtrace ready for output.
 630  *
 631  * @param array $callers backtrace array, as returned by debug_backtrace().
 632  * @param boolean $plaintext if false, generates HTML, if true generates plain text.
 633  * @return string formatted backtrace, ready for output.
 634  */
 635 function format_backtrace($callers, $plaintext = false) {
 636     // do not use $CFG->dirroot because it might not be available in destructors
 637     $dirroot = dirname(dirname(__FILE__));
 638
 639     if (empty($callers)) {
 640         return '';
 641     }
 642
 643     $from = $plaintext ? '' : '<ul style="text-align: left">';
 644     foreach ($callers as $caller) {
 645         if (!isset($caller['line'])) {
 646             $caller['line'] = '?'; // probably call_user_func()
 647         }
 648         if (!isset($caller['file'])) {
 649             $caller['file'] = 'unknownfile'; // probably call_user_func()
 650         }
 651         $from .= $plaintext ? '* ' : '<li>';
 652         $from .= 'line ' . $caller['line'] . ' of ' . str_replace($dirroot, '', $caller['file']);
 653         if (isset($caller['function'])) {
 654             $from .= ': call to ';
 655             if (isset($caller['class'])) {
 656                 $from .= $caller['class'] . $caller['type'];
 657             }
 658             $from .= $caller['function'] . '()';
 659         } else if (isset($caller['exception'])) {
 660             $from .= ': '.$caller['exception'].' thrown';
 661         }
 662         $from .= $plaintext ? "\n" : '</li>';
 663     }
 664     $from .= $plaintext ? '' : '</ul>';
 665
 666     return $from;
 667 }
 668
 669 /**
 670  * This function makes the return value of ini_get consistent if you are
 671  * setting server directives through the .htaccess file in apache.
 672  *
 673  * Current behavior for value set from php.ini On = 1, Off = [blank]
 674  * Current behavior for value set from .htaccess On = On, Off = Off
 675  * Contributed by jdell @ unr.edu
 676  *
 677  * @param string $ini_get_arg The argument to get
 678  * @return bool True for on false for not
 679  */
 680 function ini_get_bool($ini_get_arg) {
 681     $temp = ini_get($ini_get_arg);
 682
 683     if ($temp == '1' or strtolower($temp) == 'on') {
 684         return true;
 685     }
 686     return false;
 687 }
 688
 689 /**
 690  * This function verifies the sanity of PHP configuration
 691  * and stops execution if anything critical found.
 692  */
 693 function setup_validate_php_configuration() {
 694    // this must be very fast - no slow checks here!!!
 695
 696    if (ini_get_bool('register_globals')) {
 697        print_error('globalswarning', 'admin');
 698    }
 699    if (ini_get_bool('session.auto_start')) {
 700        print_error('sessionautostartwarning', 'admin');
 701    }
 702    if (ini_get_bool('magic_quotes_runtime')) {
 703        print_error('fatalmagicquotesruntime', 'admin');
 704    }
 705 }
 706
 707 /**
 708  * Initialise global $CFG variable
 709  * @return void
 710  */
 711 function initialise_cfg() {
 712     global $CFG, $DB;
 713
 714     try {
 715         if ($DB) {
 716             $localcfg = $DB->get_records_menu('config', array(), '', 'name,value');
 717             foreach ($localcfg as $name=>$value) {
 718                 if (property_exists($CFG, $name)) {
 719                     // config.php settings always take precedence
 720                     continue;
 721                 }
 722                 $CFG->{$name} = $value;
 723             }
 724         }
 725     } catch (dml_exception $e) {
 726         // most probably empty db, going to install soon
 727     }
 728 }
 729
 730 /**
 731  * Initialises $FULLME and friends. Private function. Should only be called from
 732  * setup.php.
 733  */
 734 function initialise_fullme() {
 735     global $CFG, $FULLME, $ME, $SCRIPT, $FULLSCRIPT;
 736
 737     // Detect common config error.
 738     if (substr($CFG->wwwroot, -1) == '/') {
 739         print_error('wwwrootslash', 'error');
 740     }
 741
 742     if (CLI_SCRIPT) {
 743         initialise_fullme_cli();
 744         return;
 745     }
 746
 747     $rurl = setup_get_remote_url();
 748     $wwwroot = parse_url($CFG->wwwroot.'/');
 749
 750     if (empty($rurl['host'])) {
 751         // missing host in request header, probably not a real browser, let's ignore them
 752
 753     } else if (!empty($CFG->reverseproxy)) {
 754         // $CFG->reverseproxy specifies if reverse proxy server used
 755         // Used in load balancing scenarios.
 756         // Do not abuse this to try to solve lan/wan access problems!!!!!
 757
 758     } else {
 759         if (($rurl['host'] !== $wwwroot['host']) or (!empty($wwwroot['port']) and $rurl['port'] != $wwwroot['port'])) {
 760             // Explain the problem and redirect them to the right URL
 761             if (!defined('NO_MOODLE_COOKIES')) {
 762                 define('NO_MOODLE_COOKIES', true);
 763             }
 764             redirect($CFG->wwwroot, get_string('wwwrootmismatch', 'error', $CFG->wwwroot), 3);
 765         }
 766     }
 767
 768     // Check that URL is under $CFG->wwwroot.
 769     if (strpos($rurl['path'], $wwwroot['path']) === 0) {
 770         $SCRIPT = substr($rurl['path'], strlen($wwwroot['path'])-1);
 771     } else {
 772         // Probably some weird external script
 773         $SCRIPT = $FULLSCRIPT = $FULLME = $ME = null;
 774         return;
 775     }
 776
 777     // $CFG->sslproxy specifies if external SSL appliance is used
 778     // (That is, the Moodle server uses http, with an external box translating everything to https).
 779     if (empty($CFG->sslproxy)) {
 780         if ($rurl['scheme'] === 'http' and $wwwroot['scheme'] === 'https') {
 781             print_error('sslonlyaccess', 'error');
 782         }
 783     } else {
 784         if ($wwwroot['scheme'] !== 'https') {
 785             throw new coding_exception('Must use https address in wwwroot when ssl proxy enabled!');
 786         }
 787         $rurl['scheme'] = 'https'; // make moodle believe it runs on https, squid or something else it doing it
 788     }
 789
 790     // hopefully this will stop all those "clever" admins trying to set up moodle
 791     // with two different addresses in intranet and Internet
 792     if (!empty($CFG->reverseproxy) && $rurl['host'] === $wwwroot['host']) {
 793         print_error('reverseproxyabused', 'error');
 794     }
 795
 796     $hostandport = $rurl['scheme'] . '://' . $wwwroot['host'];
 797     if (!empty($wwwroot['port'])) {
 798         $hostandport .= ':'.$wwwroot['port'];
 799     }
 800
 801     $FULLSCRIPT = $hostandport . $rurl['path'];
 802     $FULLME = $hostandport . $rurl['fullpath'];
 803     $ME = $rurl['fullpath'];
 804 }
 805
 806 /**
 807  * Initialises $FULLME and friends for command line scripts.
 808  * This is a private method for use by initialise_fullme.
 809  */
 810 function initialise_fullme_cli() {
 811     global $CFG, $FULLME, $ME, $SCRIPT, $FULLSCRIPT;
 812
 813     // Urls do not make much sense in CLI scripts
 814     $backtrace = debug_backtrace();
 815     $topfile = array_pop($backtrace);
 816     $topfile = realpath($topfile['file']);
 817     $dirroot = realpath($CFG->dirroot);
 818
 819     if (strpos($topfile, $dirroot) !== 0) {
 820         // Probably some weird external script
 821         $SCRIPT = $FULLSCRIPT = $FULLME = $ME = null;
 822     } else {
 823         $relativefile = substr($topfile, strlen($dirroot));
 824         $relativefile = str_replace('\\', '/', $relativefile); // Win fix
 825         $SCRIPT = $FULLSCRIPT = $relativefile;
 826         $FULLME = $ME = null;
 827     }
 828 }
 829
 830 /**
 831  * Get the URL that PHP/the web server thinks it is serving. Private function
 832  * used by initialise_fullme. In your code, use $PAGE->url, $SCRIPT, etc.
 833  * @return array in the same format that parse_url returns, with the addition of
 834  *      a 'fullpath' element, which includes any slasharguments path.
 835  */
 836 function setup_get_remote_url() {
 837     $rurl = array();
 838     if (isset($_SERVER['HTTP_HOST'])) {
 839         list($rurl['host']) = explode(':', $_SERVER['HTTP_HOST']);
 840     } else {
 841         $rurl['host'] = null;
 842     }
 843     $rurl['port'] = $_SERVER['SERVER_PORT'];
 844     $rurl['path'] = $_SERVER['SCRIPT_NAME']; // Script path without slash arguments
 845     $rurl['scheme'] = (empty($_SERVER['HTTPS']) or $_SERVER['HTTPS'] === 'off' or $_SERVER['HTTPS'] === 'Off' or $_SERVER['HTTPS'] === 'OFF') ? 'http' : 'https';
 846
 847     if (stripos($_SERVER['SERVER_SOFTWARE'], 'apache') !== false) {
 848         //Apache server
 849         $rurl['fullpath'] = $_SERVER['REQUEST_URI'];
 850
 851     } else if (stripos($_SERVER['SERVER_SOFTWARE'], 'iis') !== false) {
 852         //IIS - needs a lot of tweaking to make it work
 853         $rurl['fullpath'] = $_SERVER['SCRIPT_NAME'];
 854
 855         // NOTE: ignore PATH_INFO because it is incorrectly encoded using 8bit filesystem legacy encoding in IIS
 856         //       since 2.0 we rely on iis rewrite extenssion like Helicon ISAPI_rewrite
 857         //       example rule: RewriteRule ^([^\?]+?\.php)(\/.+)$ $1\?file=$2 [QSA]
 858
 859         if ($_SERVER['QUERY_STRING'] != '') {
 860             $rurl['fullpath'] .= '?'.$_SERVER['QUERY_STRING'];
 861         }
 862         $_SERVER['REQUEST_URI'] = $rurl['fullpath']; // extra IIS compatibility
 863
 864 /* NOTE: following servers are not fully tested! */
 865
 866     } else if (stripos($_SERVER['SERVER_SOFTWARE'], 'lighttpd') !== false) {
 867         //lighttpd - not officially supported
 868         $rurl['fullpath'] = $_SERVER['REQUEST_URI']; // TODO: verify this is always properly encoded
 869
 870     } else if (stripos($_SERVER['SERVER_SOFTWARE'], 'nginx') !== false) {
 871         //nginx - not officially supported
 872         if (!isset($_SERVER['SCRIPT_NAME'])) {
 873             die('Invalid server configuration detected, please try to add "fastcgi_param SCRIPT_NAME $fastcgi_script_name;" to the nginx server configuration.');
 874         }
 875         $rurl['fullpath'] = $_SERVER['REQUEST_URI']; // TODO: verify this is always properly encoded
 876
 877      } else if (stripos($_SERVER['SERVER_SOFTWARE'], 'cherokee') !== false) {
 878          //cherokee - not officially supported
 879          $rurl['fullpath'] = $_SERVER['REQUEST_URI']; // TODO: verify this is always properly encoded
 880
 881      } else if (stripos($_SERVER['SERVER_SOFTWARE'], 'zeus') !== false) {
 882          //zeus - not officially supported
 883          $rurl['fullpath'] = $_SERVER['REQUEST_URI']; // TODO: verify this is always properly encoded
 884
 885     } else if (stripos($_SERVER['SERVER_SOFTWARE'], 'LiteSpeed') !== false) {
 886         //LiteSpeed - not officially supported
 887         $rurl['fullpath'] = $_SERVER['REQUEST_URI']; // TODO: verify this is always properly encoded
 888
 889     } else if ($_SERVER['SERVER_SOFTWARE'] === 'HTTPD') {
 890         //obscure name found on some servers - this is definitely not supported
 891         $rurl['fullpath'] = $_SERVER['REQUEST_URI']; // TODO: verify this is always properly encoded
 892
 893     } else if (strpos($_SERVER['SERVER_SOFTWARE'], 'PHP') === 0) {
 894         // built-in PHP Development Server
 895         $rurl['fullpath'] = $_SERVER['REQUEST_URI'];
 896
 897     } else {
 898         throw new moodle_exception('unsupportedwebserver', 'error', '', $_SERVER['SERVER_SOFTWARE']);
 899     }
 900
 901     // sanitize the url a bit more, the encoding style may be different in vars above
 902     $rurl['fullpath'] = str_replace('"', '%22', $rurl['fullpath']);
 903     $rurl['fullpath'] = str_replace('\'', '%27', $rurl['fullpath']);
 904
 905     return $rurl;
 906 }
 907
 908 /**
 909  * Initializes our performance info early.
 910  *
 911  * Pairs up with get_performance_info() which is actually
 912  * in moodlelib.php. This function is here so that we can
 913  * call it before all the libs are pulled in.
 914  *
 915  * @uses $PERF
 916  */
 917 function init_performance_info() {
 918
 919     global $PERF, $CFG, $USER;
 920
 921     $PERF = new stdClass();
 922     $PERF->logwrites = 0;
 923     if (function_exists('microtime')) {
 924         $PERF->starttime = microtime();
 925     }
 926     if (function_exists('memory_get_usage')) {
 927         $PERF->startmemory = memory_get_usage();
 928     }
 929     if (function_exists('posix_times')) {
 930         $PERF->startposixtimes = posix_times();
 931     }
 932 }
 933
 934 /**
 935  * Indicates whether we are in the middle of the initial Moodle install.
 936  *
 937  * Very occasionally it is necessary avoid running certain bits of code before the
 938  * Moodle installation has completed. The installed flag is set in admin/index.php
 939  * after Moodle core and all the plugins have been installed, but just before
 940  * the person doing the initial install is asked to choose the admin password.
 941  *
 942  * @return boolean true if the initial install is not complete.
 943  */
 944 function during_initial_install() {
 945     global $CFG;
 946     return empty($CFG->rolesactive);
 947 }
 948
 949 /**
 950  * Function to raise the memory limit to a new value.
 951  * Will respect the memory limit if it is higher, thus allowing
 952  * settings in php.ini, apache conf or command line switches
 953  * to override it.
 954  *
 955  * The memory limit should be expressed with a constant
 956  * MEMORY_STANDARD, MEMORY_EXTRA or MEMORY_HUGE.
 957  * It is possible to use strings or integers too (eg:'128M').
 958  *
 959  * @param mixed $newlimit the new memory limit
 960  * @return bool success
 961  */
 962 function raise_memory_limit($newlimit) {
 963     global $CFG;
 964
 965     if ($newlimit == MEMORY_UNLIMITED) {
 966         ini_set('memory_limit', -1);
 967         return true;
 968
 969     } else if ($newlimit == MEMORY_STANDARD) {
 970         if (PHP_INT_SIZE > 4) {
 971             $newlimit = get_real_size('128M'); // 64bit needs more memory
 972         } else {
 973             $newlimit = get_real_size('96M');
 974         }
 975
 976     } else if ($newlimit == MEMORY_EXTRA) {
 977         if (PHP_INT_SIZE > 4) {
 978             $newlimit = get_real_size('384M'); // 64bit needs more memory
 979         } else {
 980             $newlimit = get_real_size('256M');
 981         }
 982         if (!empty($CFG->extramemorylimit)) {
 983             $extra = get_real_size($CFG->extramemorylimit);
 984             if ($extra > $newlimit) {
 985                 $newlimit = $extra;
 986             }
 987         }
 988
 989     } else if ($newlimit == MEMORY_HUGE) {
 990         $newlimit = get_real_size('2G');
 991
 992     } else {
 993         $newlimit = get_real_size($newlimit);
 994     }
 995
 996     if ($newlimit <= 0) {
 997         debugging('Invalid memory limit specified.');
 998         return false;
 999     }
1000
1001     $cur = ini_get('memory_limit');
1002     if (empty($cur)) {
1003         // if php is compiled without --enable-memory-limits
1004         // apparently memory_limit is set to ''
1005         $cur = 0;
1006     } else {
1007         if ($cur == -1){
1008             return true; // unlimited mem!
1009         }
1010         $cur = get_real_size($cur);
1011     }
1012
1013     if ($newlimit > $cur) {
1014         ini_set('memory_limit', $newlimit);
1015         return true;
1016     }
1017     return false;
1018 }
1019
1020 /**
1021  * Function to reduce the memory limit to a new value.
1022  * Will respect the memory limit if it is lower, thus allowing
1023  * settings in php.ini, apache conf or command line switches
1024  * to override it
1025  *
1026  * The memory limit should be expressed with a string (eg:'64M')
1027  *
1028  * @param string $newlimit the new memory limit
1029  * @return bool
1030  */
1031 function reduce_memory_limit($newlimit) {
1032     if (empty($newlimit)) {
1033         return false;
1034     }
1035     $cur = ini_get('memory_limit');
1036     if (empty($cur)) {
1037         // if php is compiled without --enable-memory-limits
1038         // apparently memory_limit is set to ''
1039         $cur = 0;
1040     } else {
1041         if ($cur == -1){
1042             return true; // unlimited mem!
1043         }
1044         $cur = get_real_size($cur);
1045     }
1046
1047     $new = get_real_size($newlimit);
1048     // -1 is smaller, but it means unlimited
1049     if ($new < $cur && $new != -1) {
1050         ini_set('memory_limit', $newlimit);
1051         return true;
1052     }
1053     return false;
1054 }
1055
1056 /**
1057  * Converts numbers like 10M into bytes.
1058  *
1059  * @param string $size The size to be converted
1060  * @return int
1061  */
1062 function get_real_size($size = 0) {
1063     if (!$size) {
1064         return 0;
1065     }
1066     $scan = array();
1067     $scan['GB'] = 1073741824;
1068     $scan['Gb'] = 1073741824;
1069     $scan['G'] = 1073741824;
1070     $scan['MB'] = 1048576;
1071     $scan['Mb'] = 1048576;
1072     $scan['M'] = 1048576;
1073     $scan['m'] = 1048576;
1074     $scan['KB'] = 1024;
1075     $scan['Kb'] = 1024;
1076     $scan['K'] = 1024;
1077     $scan['k'] = 1024;
1078
1079     while (list($key) = each($scan)) {
1080         if ((strlen($size)>strlen($key))&&(substr($size, strlen($size) - strlen($key))==$key)) {
1081             $size = substr($size, 0, strlen($size) - strlen($key)) * $scan[$key];
1082             break;
1083         }
1084     }
1085     return $size;
1086 }
1087
1088 /**
1089  * Try to disable all output buffering and purge
1090  * all headers.
1091  *
1092  * @access private to be called only from lib/setup.php !
1093  * @return void
1094  */
1095 function disable_output_buffering() {
1096     $olddebug = error_reporting(0);
1097
1098     // disable compression, it would prevent closing of buffers
1099     if (ini_get_bool('zlib.output_compression')) {
1100         ini_set('zlib.output_compression', 'Off');
1101     }
1102
1103     // try to flush everything all the time
1104     ob_implicit_flush(true);
1105
1106     // close all buffers if possible and discard any existing output
1107     // this can actually work around some whitespace problems in config.php
1108     while(ob_get_level()) {
1109         if (!ob_end_clean()) {
1110             // prevent infinite loop when buffer can not be closed
1111             break;
1112         }
1113     }
1114
1115     // disable any other output handlers
1116     ini_set('output_handler', '');
1117
1118     error_reporting($olddebug);
1119 }
1120
1121 /**
1122  * Check whether a major upgrade is needed. That is defined as an upgrade that
1123  * changes something really fundamental in the database, so nothing can possibly
1124  * work until the database has been updated, and that is defined by the hard-coded
1125  * version number in this function.
1126  */
1127 function redirect_if_major_upgrade_required() {
1128     global $CFG;
1129     $lastmajordbchanges = 2012051700;
1130     if (empty($CFG->version) or (int)$CFG->version < $lastmajordbchanges or
1131             during_initial_install() or !empty($CFG->adminsetuppending)) {
1132         try {
1133             @session_get_instance()->terminate_current();
1134         } catch (Exception $e) {
1135             // Ignore any errors, redirect to upgrade anyway.
1136         }
1137         $url = $CFG->wwwroot . '/' . $CFG->admin . '/index.php';
1138         @header($_SERVER['SERVER_PROTOCOL'] . ' 303 See Other');
1139         @header('Location: ' . $url);
1140         echo bootstrap_renderer::plain_redirect_message(htmlspecialchars($url));
1141         exit;
1142     }
1143 }
1144
1145 /**
1146  * Function to check if a directory exists and by default create it if not exists.
1147  *
1148  * Previously this was accepting paths only from dataroot, but we now allow
1149  * files outside of dataroot if you supply custom paths for some settings in config.php.
1150  * This function does not verify that the directory is writable.
1151  *
1152  * NOTE: this function uses current file stat cache,
1153  *       please use clearstatcache() before this if you expect that the
1154  *       directories may have been removed recently from a different request.
1155  *
1156  * @param string $dir absolute directory path
1157  * @param boolean $create directory if does not exist
1158  * @param boolean $recursive create directory recursively
1159  * @return boolean true if directory exists or created, false otherwise
1160  */
1161 function check_dir_exists($dir, $create = true, $recursive = true) {
1162     global $CFG;
1163
1164     umask(0000); // just in case some evil code changed it
1165
1166     if (is_dir($dir)) {
1167         return true;
1168     }
1169
1170     if (!$create) {
1171         return false;
1172     }
1173
1174     return mkdir($dir, $CFG->directorypermissions, $recursive);
1175 }
1176
1177 /**
1178  * Create a directory and make sure it is writable.
1179  *
1180  * @private
1181  * @param string $dir  the full path of the directory to be created
1182  * @param bool $exceptiononerror throw exception if error encountered
1183  * @return string|false Returns full path to directory if successful, false if not; may throw exception
1184  */
1185 function make_writable_directory($dir, $exceptiononerror = true) {
1186     global $CFG;
1187
1188     if (file_exists($dir) and !is_dir($dir)) {
1189         if ($exceptiononerror) {
1190             throw new coding_exception($dir.' directory can not be created, file with the same name already exists.');
1191         } else {
1192             return false;
1193         }
1194     }
1195
1196     umask(0000); // just in case some evil code changed it
1197
1198     if (!file_exists($dir)) {
1199         if (!mkdir($dir, $CFG->directorypermissions, true)) {
1200             if ($exceptiononerror) {
1201                 throw new invalid_dataroot_permissions($dir.' can not be created, check permissions.');
1202             } else {
1203                 return false;
1204             }
1205         }
1206     }
1207
1208     if (!is_writable($dir)) {
1209         if ($exceptiononerror) {
1210             throw new invalid_dataroot_permissions($dir.' is not writable, check permissions.');
1211         } else {
1212             return false;
1213         }
1214     }
1215
1216     return $dir;
1217 }
1218
1219 /**
1220  * Protect a directory from web access.
1221  * Could be extended in the future to support other mechanisms (e.g. other webservers).
1222  *
1223  * @private
1224  * @param string $dir  the full path of the directory to be protected
1225  */
1226 function protect_directory($dir) {
1227     // Make sure a .htaccess file is here, JUST IN CASE the files area is in the open and .htaccess is supported
1228     if (!file_exists("$dir/.htaccess")) {
1229         if ($handle = fopen("$dir/.htaccess", 'w')) {   // For safety
1230             @fwrite($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");
1231             @fclose($handle);
1232         }
1233     }
1234 }
1235
1236 /**
1237  * Create a directory under dataroot and make sure it is writable.
1238  * Do not use for temporary and cache files - see make_temp_directory() and make_cache_directory().
1239  *
1240  * @param string $directory  the full path of the directory to be created under $CFG->dataroot
1241  * @param bool $exceptiononerror throw exception if error encountered
1242  * @return string|false Returns full path to directory if successful, false if not; may throw exception
1243  */
1244 function make_upload_directory($directory, $exceptiononerror = true) {
1245     global $CFG;
1246
1247     if (strpos($directory, 'temp/') === 0 or $directory === 'temp') {
1248         debugging('Use make_temp_directory() for creation of temporary directory and $CFG->tempdir to get the location.');
1249
1250     } else if (strpos($directory, 'cache/') === 0 or $directory === 'cache') {
1251         debugging('Use make_cache_directory() for creation of chache directory and $CFG->cachedir to get the location.');
1252     }
1253
1254     protect_directory($CFG->dataroot);
1255     return make_writable_directory("$CFG->dataroot/$directory", $exceptiononerror);
1256 }
1257
1258 /**
1259  * Create a directory under tempdir and make sure it is writable.
1260  * Temporary files should be used during the current request only!
1261  *
1262  * @param string $directory  the full path of the directory to be created under $CFG->tempdir
1263  * @param bool $exceptiononerror throw exception if error encountered
1264  * @return string|false Returns full path to directory if successful, false if not; may throw exception
1265  */
1266 function make_temp_directory($directory, $exceptiononerror = true) {
1267     global $CFG;
1268     if ($CFG->tempdir !== "$CFG->dataroot/temp") {
1269         check_dir_exists($CFG->tempdir, true, true);
1270         protect_directory($CFG->tempdir);
1271     } else {
1272         protect_directory($CFG->dataroot);
1273     }
1274     return make_writable_directory("$CFG->tempdir/$directory", $exceptiononerror);
1275 }
1276
1277 /**
1278  * Create a directory under cachedir and make sure it is writable.
1279  *
1280  * @param string $directory  the full path of the directory to be created under $CFG->cachedir
1281  * @param bool $exceptiononerror throw exception if error encountered
1282  * @return string|false Returns full path to directory if successful, false if not; may throw exception
1283  */
1284 function make_cache_directory($directory, $exceptiononerror = true) {
1285     global $CFG;
1286     if ($CFG->cachedir !== "$CFG->dataroot/cache") {
1287         check_dir_exists($CFG->cachedir, true, true);
1288         protect_directory($CFG->cachedir);
1289     } else {
1290         protect_directory($CFG->dataroot);
1291     }
1292     return make_writable_directory("$CFG->cachedir/$directory", $exceptiononerror);
1293 }
1294
1295
1296 /**
1297  * Initialises an Memcached instance
1298  * @global memcached $MCACHE
1299  * @return boolean Returns true if an mcached instance could be successfully initialised
1300  */
1301 function init_memcached() {
1302     global $CFG, $MCACHE;
1303
1304     include_once($CFG->libdir . '/memcached.class.php');
1305     $MCACHE = new memcached;
1306     if ($MCACHE->status()) {
1307         return true;
1308     }
1309     unset($MCACHE);
1310     return false;
1311 }
1312
1313 /**
1314  * Initialises an eAccelerator instance
1315  * @global eaccelerator $MCACHE
1316  * @return boolean Returns true if an eAccelerator instance could be successfully initialised
1317  */
1318 function init_eaccelerator() {
1319     global $CFG, $MCACHE;
1320
1321     include_once($CFG->libdir . '/eaccelerator.class.php');
1322     $MCACHE = new eaccelerator;
1323     if ($MCACHE->status()) {
1324         return true;
1325     }
1326     unset($MCACHE);
1327     return false;
1328 }
1329
1330 /**
1331  * Checks if current user is a web crawler.
1332  *
1333  * This list can not be made complete, this is not a security
1334  * restriction, we make the list only to help these sites
1335  * especially when automatic guest login is disabled.
1336  *
1337  * If admin needs security they should enable forcelogin
1338  * and disable guest access!!
1339  *
1340  * @return bool
1341  */
1342 function is_web_crawler() {
1343     if (!empty($_SERVER['HTTP_USER_AGENT'])) {
1344         if (strpos($_SERVER['HTTP_USER_AGENT'], 'Googlebot') !== false ) {
1345             return true;
1346         } else if (strpos($_SERVER['HTTP_USER_AGENT'], 'google.com') !== false ) { // Google
1347             return true;
1348         } else if (strpos($_SERVER['HTTP_USER_AGENT'], 'Yahoo! Slurp') !== false ) {  // Yahoo
1349             return true;
1350         } else if (strpos($_SERVER['HTTP_USER_AGENT'], '[ZSEBOT]') !== false ) {  // Zoomspider
1351             return true;
1352         } else if (strpos($_SERVER['HTTP_USER_AGENT'], 'MSNBOT') !== false ) {  // MSN Search
1353             return true;
1354         } else if (strpos($_SERVER['HTTP_USER_AGENT'], 'Yandex') !== false ) {
1355             return true;
1356         } else if (strpos($_SERVER['HTTP_USER_AGENT'], 'AltaVista') !== false ) {
1357             return true;
1358         }
1359     }
1360     return false;
1361 }
1362
1363 /**
1364  * This class solves the problem of how to initialise $OUTPUT.
1365  *
1366  * The problem is caused be two factors
1367  * <ol>
1368  * <li>On the one hand, we cannot be sure when output will start. In particular,
1369  * an error, which needs to be displayed, could be thrown at any time.</li>
1370  * <li>On the other hand, we cannot be sure when we will have all the information
1371  * necessary to correctly initialise $OUTPUT. $OUTPUT depends on the theme, which
1372  * (potentially) depends on the current course, course categories, and logged in user.
1373  * It also depends on whether the current page requires HTTPS.</li>
1374  * </ol>
1375  *
1376  * So, it is hard to find a single natural place during Moodle script execution,
1377  * which we can guarantee is the right time to initialise $OUTPUT. Instead we
1378  * adopt the following strategy
1379  * <ol>
1380  * <li>We will initialise $OUTPUT the first time it is used.</li>
1381  * <li>If, after $OUTPUT has been initialised, the script tries to change something
1382  * that $OUTPUT depends on, we throw an exception making it clear that the script
1383  * did something wrong.
1384  * </ol>
1385  *
1386  * The only problem with that is, how do we initialise $OUTPUT on first use if,
1387  * it is going to be used like $OUTPUT->somthing(...)? Well that is where this
1388  * class comes in. Initially, we set up $OUTPUT = new bootstrap_renderer(). Then,
1389  * when any method is called on that object, we initialise $OUTPUT, and pass the call on.
1390  *
1391  * Note that this class is used before lib/outputlib.php has been loaded, so we
1392  * must be careful referring to classes/functions from there, they may not be
1393  * defined yet, and we must avoid fatal errors.
1394  *
1395  * @copyright 2009 Tim Hunt
1396  * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
1397  * @since     Moodle 2.0
1398  */
1399 class bootstrap_renderer {
1400     /**
1401      * Handles re-entrancy. Without this, errors or debugging output that occur
1402      * during the initialisation of $OUTPUT, cause infinite recursion.
1403      * @var boolean
1404      */
1405     protected $initialising = false;
1406
1407     /**
1408      * Have we started output yet?
1409      * @return boolean true if the header has been printed.
1410      */
1411     public function has_started() {
1412         return false;
1413     }
1414
1415     /**
1416      * Constructor - to be used by core code only.
1417      * @param string $method The method to call
1418      * @param array $arguments Arguments to pass to the method being called
1419      * @return string
1420      */
1421     public function __call($method, $arguments) {
1422         global $OUTPUT, $PAGE;
1423
1424         $recursing = false;
1425         if ($method == 'notification') {
1426             // Catch infinite recursion caused by debugging output during print_header.
1427             $backtrace = debug_backtrace();
1428             array_shift($backtrace);
1429             array_shift($backtrace);
1430             $recursing = is_early_init($backtrace);
1431         }
1432
1433         $earlymethods = array(
1434             'fatal_error' => 'early_error',
1435             'notification' => 'early_notification',
1436         );
1437
1438         // If lib/outputlib.php has been loaded, call it.
1439         if (!empty($PAGE) && !$recursing) {
1440             if (array_key_exists($method, $earlymethods)) {
1441                 //prevent PAGE->context warnings - exceptions might appear before we set any context
1442                 $PAGE->set_context(null);
1443             }
1444             $PAGE->initialise_theme_and_output();
1445             return call_user_func_array(array($OUTPUT, $method), $arguments);
1446         }
1447
1448         $this->initialising = true;
1449
1450         // Too soon to initialise $OUTPUT, provide a couple of key methods.
1451         if (array_key_exists($method, $earlymethods)) {
1452             return call_user_func_array(array('bootstrap_renderer', $earlymethods[$method]), $arguments);
1453         }
1454
1455         throw new coding_exception('Attempt to start output before enough information is known to initialise the theme.');
1456     }
1457
1458     /**
1459      * Returns nicely formatted error message in a div box.
1460      * @static
1461      * @param string $message error message
1462      * @param string $moreinfourl (ignored in early errors)
1463      * @param string $link (ignored in early errors)
1464      * @param array $backtrace
1465      * @param string $debuginfo
1466      * @return string
1467      */
1468     public static function early_error_content($message, $moreinfourl, $link, $backtrace, $debuginfo = null) {
1469         global $CFG;
1470
1471         $content = '<div style="margin-top: 6em; margin-left:auto; margin-right:auto; color:#990000; text-align:center; font-size:large; border-width:1px;
1472 border-color:black; background-color:#ffffee; border-style:solid; border-radius: 20px; border-collapse: collapse;
1473 width: 80%; -moz-border-radius: 20px; padding: 15px">
1474 ' . $message . '
1475 </div>';
1476         if (!empty($CFG->debug) && $CFG->debug >= DEBUG_DEVELOPER) {
1477             if (!empty($debuginfo)) {
1478                 $debuginfo = s($debuginfo); // removes all nasty JS
1479                 $debuginfo = str_replace("\n", '<br />', $debuginfo); // keep newlines
1480                 $content .= '<div class="notifytiny">Debug info: ' . $debuginfo . '</div>';
1481             }
1482             if (!empty($backtrace)) {
1483                 $content .= '<div class="notifytiny">Stack trace: ' . format_backtrace($backtrace, false) . '</div>';
1484             }
1485         }
1486
1487         return $content;
1488     }
1489
1490     /**
1491      * This function should only be called by this class, or from exception handlers
1492      * @static
1493      * @param string $message error message
1494      * @param string $moreinfourl (ignored in early errors)
1495      * @param string $link (ignored in early errors)
1496      * @param array $backtrace
1497      * @param string $debuginfo extra information for developers
1498      * @return string
1499      */
1500     public static function early_error($message, $moreinfourl, $link, $backtrace, $debuginfo = null) {
1501         global $CFG;
1502
1503         if (CLI_SCRIPT) {
1504             echo "!!! $message !!!\n";
1505             if (!empty($CFG->debug) and $CFG->debug >= DEBUG_DEVELOPER) {
1506                 if (!empty($debuginfo)) {
1507                     echo "\nDebug info: $debuginfo";
1508                 }
1509                 if (!empty($backtrace)) {
1510                     echo "\nStack trace: " . format_backtrace($backtrace, true);
1511                 }
1512             }
1513             return;
1514
1515         } else if (AJAX_SCRIPT) {
1516             $e = new stdClass();
1517             $e->error      = $message;
1518             $e->stacktrace = NULL;
1519             $e->debuginfo  = NULL;
1520             if (!empty($CFG->debug) and $CFG->debug >= DEBUG_DEVELOPER) {
1521                 if (!empty($debuginfo)) {
1522                     $e->debuginfo = $debuginfo;
1523                 }
1524                 if (!empty($backtrace)) {
1525                     $e->stacktrace = format_backtrace($backtrace, true);
1526                 }
1527             }
1528             @header('Content-Type: application/json; charset=utf-8');
1529             echo json_encode($e);
1530             return;
1531         }
1532
1533         // In the name of protocol correctness, monitoring and performance
1534         // profiling, set the appropriate error headers for machine consumption
1535         if (isset($_SERVER['SERVER_PROTOCOL'])) {
1536             // Avoid it with cron.php. Note that we assume it's HTTP/1.x
1537             // The 503 ode here means our Moodle does not work at all, the error happened too early
1538             @header($_SERVER['SERVER_PROTOCOL'] . ' 503 Service Unavailable');
1539         }
1540
1541         // better disable any caching
1542         @header('Content-Type: text/html; charset=utf-8');
1543         @header('Cache-Control: no-store, no-cache, must-revalidate');
1544         @header('Cache-Control: post-check=0, pre-check=0', false);
1545         @header('Pragma: no-cache');
1546         @header('Expires: Mon, 20 Aug 1969 09:23:00 GMT');
1547         @header('Last-Modified: ' . gmdate('D, d M Y H:i:s') . ' GMT');
1548
1549         if (function_exists('get_string')) {
1550             $strerror = get_string('error');
1551         } else {
1552             $strerror = 'Error';
1553         }
1554
1555         $content = self::early_error_content($message, $moreinfourl, $link, $backtrace, $debuginfo);
1556
1557         return self::plain_page($strerror, $content);
1558     }
1559
1560     /**
1561      * Early notification message
1562      * @static
1563      * @param string $message
1564      * @param string $classes usually notifyproblem or notifysuccess
1565      * @return string
1566      */
1567     public static function early_notification($message, $classes = 'notifyproblem') {
1568         return '<div class="' . $classes . '">' . $message . '</div>';
1569     }
1570
1571     /**
1572      * Page should redirect message.
1573      * @static
1574      * @param string $encodedurl redirect url
1575      * @return string
1576      */
1577     public static function plain_redirect_message($encodedurl) {
1578         $message = '<div style="margin-top: 3em; margin-left:auto; margin-right:auto; text-align:center;">' . get_string('pageshouldredirect') . '<br /><a href="'.
1579                 $encodedurl .'">'. get_string('continue') .'</a></div>';
1580         return self::plain_page(get_string('redirect'), $message);
1581     }
1582
1583     /**
1584      * Early redirection page, used before full init of $PAGE global
1585      * @static
1586      * @param string $encodedurl redirect url
1587      * @param string $message redirect message
1588      * @param int $delay time in seconds
1589      * @return string redirect page
1590      */
1591     public static function early_redirect_message($encodedurl, $message, $delay) {
1592         $meta = '<meta http-equiv="refresh" content="'. $delay .'; url='. $encodedurl .'" />';
1593         $content = self::early_error_content($message, null, null, null);
1594         $content .= self::plain_redirect_message($encodedurl);
1595
1596         return self::plain_page(get_string('redirect'), $content, $meta);
1597     }
1598
1599     /**
1600      * Output basic html page.
1601      * @static
1602      * @param string $title page title
1603      * @param string $content page content
1604      * @param string $meta meta tag
1605      * @return string html page
1606      */
1607     protected static function plain_page($title, $content, $meta = '') {
1608         if (function_exists('get_string') && function_exists('get_html_lang')) {
1609             $htmllang = get_html_lang();
1610         } else {
1611             $htmllang = '';
1612         }
1613
1614         return '<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
1615 <html xmlns="http://www.w3.org/1999/xhtml" ' . $htmllang . '>
1616 <head>
1617 <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
1618 '.$meta.'
1619 <title>' . $title . '</title>
1620 </head><body>' . $content . '</body></html>';
1621     }
1622 }