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             $paranetcontext = get_context_instance_by_id(get_parent_contextid($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
 569  *
 570  * @global object
 571  * @param string $path the end of the URL.
 572  * @return string The MoodleDocs URL in the user's language. for example {@link http://docs.moodle.org/en/ http://docs.moodle.org/en/$path}
 573  */
 574 function get_docs_url($path=null) {
 575     global $CFG;
 576     // Check that $CFG->branch has been set up, during installation it won't be.
 577     if (empty($CFG->branch)) {
 578         // It's not there yet so look at version.php
 579         include($CFG->dirroot.'/version.php');
 580     } else {
 581         // We can use $CFG->branch and avoid having to include version.php
 582         $branch = $CFG->branch;
 583     }
 584     // ensure branch is valid.
 585     if (!$branch) {
 586         // We should never get here but in case we do lets set $branch to .
 587         // the smart one's will know that this is the current directory
 588         // and the smarter ones will know that there is some smart matching
 589         // that will ensure people end up at the latest version of the docs.
 590         $branch = '.';
 591     }
 592     if (!empty($CFG->docroot)) {
 593         return $CFG->docroot . '/' . $branch . '/' . current_language() . '/' . $path;
 594     } else {
 595         return 'http://docs.moodle.org/'. $branch . '/en/' . $path;
 596     }
 597 }
 598
 599 /**
 600  * Formats a backtrace ready for output.
 601  *
 602  * @param array $callers backtrace array, as returned by debug_backtrace().
 603  * @param boolean $plaintext if false, generates HTML, if true generates plain text.
 604  * @return string formatted backtrace, ready for output.
 605  */
 606 function format_backtrace($callers, $plaintext = false) {
 607     // do not use $CFG->dirroot because it might not be available in destructors
 608     $dirroot = dirname(dirname(__FILE__));
 609
 610     if (empty($callers)) {
 611         return '';
 612     }
 613
 614     $from = $plaintext ? '' : '<ul style="text-align: left">';
 615     foreach ($callers as $caller) {
 616         if (!isset($caller['line'])) {
 617             $caller['line'] = '?'; // probably call_user_func()
 618         }
 619         if (!isset($caller['file'])) {
 620             $caller['file'] = 'unknownfile'; // probably call_user_func()
 621         }
 622         $from .= $plaintext ? '* ' : '<li>';
 623         $from .= 'line ' . $caller['line'] . ' of ' . str_replace($dirroot, '', $caller['file']);
 624         if (isset($caller['function'])) {
 625             $from .= ': call to ';
 626             if (isset($caller['class'])) {
 627                 $from .= $caller['class'] . $caller['type'];
 628             }
 629             $from .= $caller['function'] . '()';
 630         } else if (isset($caller['exception'])) {
 631             $from .= ': '.$caller['exception'].' thrown';
 632         }
 633         $from .= $plaintext ? "\n" : '</li>';
 634     }
 635     $from .= $plaintext ? '' : '</ul>';
 636
 637     return $from;
 638 }
 639
 640 /**
 641  * This function makes the return value of ini_get consistent if you are
 642  * setting server directives through the .htaccess file in apache.
 643  *
 644  * Current behavior for value set from php.ini On = 1, Off = [blank]
 645  * Current behavior for value set from .htaccess On = On, Off = Off
 646  * Contributed by jdell @ unr.edu
 647  *
 648  * @param string $ini_get_arg The argument to get
 649  * @return bool True for on false for not
 650  */
 651 function ini_get_bool($ini_get_arg) {
 652     $temp = ini_get($ini_get_arg);
 653
 654     if ($temp == '1' or strtolower($temp) == 'on') {
 655         return true;
 656     }
 657     return false;
 658 }
 659
 660 /**
 661  * This function verifies the sanity of PHP configuration
 662  * and stops execution if anything critical found.
 663  */
 664 function setup_validate_php_configuration() {
 665    // this must be very fast - no slow checks here!!!
 666
 667    if (ini_get_bool('register_globals')) {
 668        print_error('globalswarning', 'admin');
 669    }
 670    if (ini_get_bool('session.auto_start')) {
 671        print_error('sessionautostartwarning', 'admin');
 672    }
 673    if (ini_get_bool('magic_quotes_runtime')) {
 674        print_error('fatalmagicquotesruntime', 'admin');
 675    }
 676 }
 677
 678 /**
 679  * Initialise global $CFG variable
 680  * @return void
 681  */
 682 function initialise_cfg() {
 683     global $CFG, $DB;
 684
 685     try {
 686         if ($DB) {
 687             $localcfg = $DB->get_records_menu('config', array(), '', 'name,value');
 688             foreach ($localcfg as $name=>$value) {
 689                 if (property_exists($CFG, $name)) {
 690                     // config.php settings always take precedence
 691                     continue;
 692                 }
 693                 $CFG->{$name} = $value;
 694             }
 695         }
 696     } catch (dml_exception $e) {
 697         // most probably empty db, going to install soon
 698     }
 699 }
 700
 701 /**
 702  * Initialises $FULLME and friends. Private function. Should only be called from
 703  * setup.php.
 704  */
 705 function initialise_fullme() {
 706     global $CFG, $FULLME, $ME, $SCRIPT, $FULLSCRIPT;
 707
 708     // Detect common config error.
 709     if (substr($CFG->wwwroot, -1) == '/') {
 710         print_error('wwwrootslash', 'error');
 711     }
 712
 713     if (CLI_SCRIPT) {
 714         initialise_fullme_cli();
 715         return;
 716     }
 717
 718     $rurl = setup_get_remote_url();
 719     $wwwroot = parse_url($CFG->wwwroot.'/');
 720
 721     if (empty($rurl['host'])) {
 722         // missing host in request header, probably not a real browser, let's ignore them
 723
 724     } else if (!empty($CFG->reverseproxy)) {
 725         // $CFG->reverseproxy specifies if reverse proxy server used
 726         // Used in load balancing scenarios.
 727         // Do not abuse this to try to solve lan/wan access problems!!!!!
 728
 729     } else {
 730         if (($rurl['host'] !== $wwwroot['host']) or (!empty($wwwroot['port']) and $rurl['port'] != $wwwroot['port'])) {
 731             // Explain the problem and redirect them to the right URL
 732             if (!defined('NO_MOODLE_COOKIES')) {
 733                 define('NO_MOODLE_COOKIES', true);
 734             }
 735             redirect($CFG->wwwroot, get_string('wwwrootmismatch', 'error', $CFG->wwwroot), 3);
 736         }
 737     }
 738
 739     // Check that URL is under $CFG->wwwroot.
 740     if (strpos($rurl['path'], $wwwroot['path']) === 0) {
 741         $SCRIPT = substr($rurl['path'], strlen($wwwroot['path'])-1);
 742     } else {
 743         // Probably some weird external script
 744         $SCRIPT = $FULLSCRIPT = $FULLME = $ME = null;
 745         return;
 746     }
 747
 748     // $CFG->sslproxy specifies if external SSL appliance is used
 749     // (That is, the Moodle server uses http, with an external box translating everything to https).
 750     if (empty($CFG->sslproxy)) {
 751         if ($rurl['scheme'] === 'http' and $wwwroot['scheme'] === 'https') {
 752             print_error('sslonlyaccess', 'error');
 753         }
 754     } else {
 755         if ($wwwroot['scheme'] !== 'https') {
 756             throw new coding_exception('Must use https address in wwwroot when ssl proxy enabled!');
 757         }
 758         $rurl['scheme'] = 'https'; // make moodle believe it runs on https, squid or something else it doing it
 759     }
 760
 761     // hopefully this will stop all those "clever" admins trying to set up moodle
 762     // with two different addresses in intranet and Internet
 763     if (!empty($CFG->reverseproxy) && $rurl['host'] === $wwwroot['host']) {
 764         print_error('reverseproxyabused', 'error');
 765     }
 766
 767     $hostandport = $rurl['scheme'] . '://' . $wwwroot['host'];
 768     if (!empty($wwwroot['port'])) {
 769         $hostandport .= ':'.$wwwroot['port'];
 770     }
 771
 772     $FULLSCRIPT = $hostandport . $rurl['path'];
 773     $FULLME = $hostandport . $rurl['fullpath'];
 774     $ME = $rurl['fullpath'];
 775 }
 776
 777 /**
 778  * Initialises $FULLME and friends for command line scripts.
 779  * This is a private method for use by initialise_fullme.
 780  */
 781 function initialise_fullme_cli() {
 782     global $CFG, $FULLME, $ME, $SCRIPT, $FULLSCRIPT;
 783
 784     // Urls do not make much sense in CLI scripts
 785     $backtrace = debug_backtrace();
 786     $topfile = array_pop($backtrace);
 787     $topfile = realpath($topfile['file']);
 788     $dirroot = realpath($CFG->dirroot);
 789
 790     if (strpos($topfile, $dirroot) !== 0) {
 791         // Probably some weird external script
 792         $SCRIPT = $FULLSCRIPT = $FULLME = $ME = null;
 793     } else {
 794         $relativefile = substr($topfile, strlen($dirroot));
 795         $relativefile = str_replace('\\', '/', $relativefile); // Win fix
 796         $SCRIPT = $FULLSCRIPT = $relativefile;
 797         $FULLME = $ME = null;
 798     }
 799 }
 800
 801 /**
 802  * Get the URL that PHP/the web server thinks it is serving. Private function
 803  * used by initialise_fullme. In your code, use $PAGE->url, $SCRIPT, etc.
 804  * @return array in the same format that parse_url returns, with the addition of
 805  *      a 'fullpath' element, which includes any slasharguments path.
 806  */
 807 function setup_get_remote_url() {
 808     $rurl = array();
 809     if (isset($_SERVER['HTTP_HOST'])) {
 810         list($rurl['host']) = explode(':', $_SERVER['HTTP_HOST']);
 811     } else {
 812         $rurl['host'] = null;
 813     }
 814     $rurl['port'] = $_SERVER['SERVER_PORT'];
 815     $rurl['path'] = $_SERVER['SCRIPT_NAME']; // Script path without slash arguments
 816     $rurl['scheme'] = (empty($_SERVER['HTTPS']) or $_SERVER['HTTPS'] === 'off' or $_SERVER['HTTPS'] === 'Off' or $_SERVER['HTTPS'] === 'OFF') ? 'http' : 'https';
 817
 818     if (stripos($_SERVER['SERVER_SOFTWARE'], 'apache') !== false) {
 819         //Apache server
 820         $rurl['fullpath'] = $_SERVER['REQUEST_URI'];
 821
 822     } else if (stripos($_SERVER['SERVER_SOFTWARE'], 'iis') !== false) {
 823         //IIS - needs a lot of tweaking to make it work
 824         $rurl['fullpath'] = $_SERVER['SCRIPT_NAME'];
 825
 826         // NOTE: ignore PATH_INFO because it is incorrectly encoded using 8bit filesystem legacy encoding in IIS
 827         //       since 2.0 we rely on iis rewrite extenssion like Helicon ISAPI_rewrite
 828         //       example rule: RewriteRule ^([^\?]+?\.php)(\/.+)$ $1\?file=$2 [QSA]
 829
 830         if ($_SERVER['QUERY_STRING'] != '') {
 831             $rurl['fullpath'] .= '?'.$_SERVER['QUERY_STRING'];
 832         }
 833         $_SERVER['REQUEST_URI'] = $rurl['fullpath']; // extra IIS compatibility
 834
 835 /* NOTE: following servers are not fully tested! */
 836
 837     } else if (stripos($_SERVER['SERVER_SOFTWARE'], 'lighttpd') !== false) {
 838         //lighttpd - not officially supported
 839         $rurl['fullpath'] = $_SERVER['REQUEST_URI']; // TODO: verify this is always properly encoded
 840
 841     } else if (stripos($_SERVER['SERVER_SOFTWARE'], 'nginx') !== false) {
 842         //nginx - not officially supported
 843         if (!isset($_SERVER['SCRIPT_NAME'])) {
 844             die('Invalid server configuration detected, please try to add "fastcgi_param SCRIPT_NAME $fastcgi_script_name;" to the nginx server configuration.');
 845         }
 846         $rurl['fullpath'] = $_SERVER['REQUEST_URI']; // TODO: verify this is always properly encoded
 847
 848      } else if (stripos($_SERVER['SERVER_SOFTWARE'], 'cherokee') !== false) {
 849          //cherokee - not officially supported
 850          $rurl['fullpath'] = $_SERVER['REQUEST_URI']; // TODO: verify this is always properly encoded
 851
 852      } else if (stripos($_SERVER['SERVER_SOFTWARE'], 'zeus') !== false) {
 853          //zeus - not officially supported
 854          $rurl['fullpath'] = $_SERVER['REQUEST_URI']; // TODO: verify this is always properly encoded
 855
 856     } else if (stripos($_SERVER['SERVER_SOFTWARE'], 'LiteSpeed') !== false) {
 857         //LiteSpeed - not officially supported
 858         $rurl['fullpath'] = $_SERVER['REQUEST_URI']; // TODO: verify this is always properly encoded
 859
 860     } else if ($_SERVER['SERVER_SOFTWARE'] === 'HTTPD') {
 861         //obscure name found on some servers - this is definitely not supported
 862         $rurl['fullpath'] = $_SERVER['REQUEST_URI']; // TODO: verify this is always properly encoded
 863
 864     } else if (strpos($_SERVER['SERVER_SOFTWARE'], 'PHP') === 0) {
 865         // built-in PHP Development Server
 866         $rurl['fullpath'] = $_SERVER['REQUEST_URI'];
 867
 868     } else {
 869         throw new moodle_exception('unsupportedwebserver', 'error', '', $_SERVER['SERVER_SOFTWARE']);
 870     }
 871
 872     // sanitize the url a bit more, the encoding style may be different in vars above
 873     $rurl['fullpath'] = str_replace('"', '%22', $rurl['fullpath']);
 874     $rurl['fullpath'] = str_replace('\'', '%27', $rurl['fullpath']);
 875
 876     return $rurl;
 877 }
 878
 879 /**
 880  * Initializes our performance info early.
 881  *
 882  * Pairs up with get_performance_info() which is actually
 883  * in moodlelib.php. This function is here so that we can
 884  * call it before all the libs are pulled in.
 885  *
 886  * @uses $PERF
 887  */
 888 function init_performance_info() {
 889
 890     global $PERF, $CFG, $USER;
 891
 892     $PERF = new stdClass();
 893     $PERF->logwrites = 0;
 894     if (function_exists('microtime')) {
 895         $PERF->starttime = microtime();
 896     }
 897     if (function_exists('memory_get_usage')) {
 898         $PERF->startmemory = memory_get_usage();
 899     }
 900     if (function_exists('posix_times')) {
 901         $PERF->startposixtimes = posix_times();
 902     }
 903 }
 904
 905 /**
 906  * Indicates whether we are in the middle of the initial Moodle install.
 907  *
 908  * Very occasionally it is necessary avoid running certain bits of code before the
 909  * Moodle installation has completed. The installed flag is set in admin/index.php
 910  * after Moodle core and all the plugins have been installed, but just before
 911  * the person doing the initial install is asked to choose the admin password.
 912  *
 913  * @return boolean true if the initial install is not complete.
 914  */
 915 function during_initial_install() {
 916     global $CFG;
 917     return empty($CFG->rolesactive);
 918 }
 919
 920 /**
 921  * Function to raise the memory limit to a new value.
 922  * Will respect the memory limit if it is higher, thus allowing
 923  * settings in php.ini, apache conf or command line switches
 924  * to override it.
 925  *
 926  * The memory limit should be expressed with a constant
 927  * MEMORY_STANDARD, MEMORY_EXTRA or MEMORY_HUGE.
 928  * It is possible to use strings or integers too (eg:'128M').
 929  *
 930  * @param mixed $newlimit the new memory limit
 931  * @return bool success
 932  */
 933 function raise_memory_limit($newlimit) {
 934     global $CFG;
 935
 936     if ($newlimit == MEMORY_UNLIMITED) {
 937         ini_set('memory_limit', -1);
 938         return true;
 939
 940     } else if ($newlimit == MEMORY_STANDARD) {
 941         if (PHP_INT_SIZE > 4) {
 942             $newlimit = get_real_size('128M'); // 64bit needs more memory
 943         } else {
 944             $newlimit = get_real_size('96M');
 945         }
 946
 947     } else if ($newlimit == MEMORY_EXTRA) {
 948         if (PHP_INT_SIZE > 4) {
 949             $newlimit = get_real_size('384M'); // 64bit needs more memory
 950         } else {
 951             $newlimit = get_real_size('256M');
 952         }
 953         if (!empty($CFG->extramemorylimit)) {
 954             $extra = get_real_size($CFG->extramemorylimit);
 955             if ($extra > $newlimit) {
 956                 $newlimit = $extra;
 957             }
 958         }
 959
 960     } else if ($newlimit == MEMORY_HUGE) {
 961         $newlimit = get_real_size('2G');
 962
 963     } else {
 964         $newlimit = get_real_size($newlimit);
 965     }
 966
 967     if ($newlimit <= 0) {
 968         debugging('Invalid memory limit specified.');
 969         return false;
 970     }
 971
 972     $cur = ini_get('memory_limit');
 973     if (empty($cur)) {
 974         // if php is compiled without --enable-memory-limits
 975         // apparently memory_limit is set to ''
 976         $cur = 0;
 977     } else {
 978         if ($cur == -1){
 979             return true; // unlimited mem!
 980         }
 981         $cur = get_real_size($cur);
 982     }
 983
 984     if ($newlimit > $cur) {
 985         ini_set('memory_limit', $newlimit);
 986         return true;
 987     }
 988     return false;
 989 }
 990
 991 /**
 992  * Function to reduce the memory limit to a new value.
 993  * Will respect the memory limit if it is lower, thus allowing
 994  * settings in php.ini, apache conf or command line switches
 995  * to override it
 996  *
 997  * The memory limit should be expressed with a string (eg:'64M')
 998  *
 999  * @param string $newlimit the new memory limit
1000  * @return bool
1001  */
1002 function reduce_memory_limit($newlimit) {
1003     if (empty($newlimit)) {
1004         return false;
1005     }
1006     $cur = ini_get('memory_limit');
1007     if (empty($cur)) {
1008         // if php is compiled without --enable-memory-limits
1009         // apparently memory_limit is set to ''
1010         $cur = 0;
1011     } else {
1012         if ($cur == -1){
1013             return true; // unlimited mem!
1014         }
1015         $cur = get_real_size($cur);
1016     }
1017
1018     $new = get_real_size($newlimit);
1019     // -1 is smaller, but it means unlimited
1020     if ($new < $cur && $new != -1) {
1021         ini_set('memory_limit', $newlimit);
1022         return true;
1023     }
1024     return false;
1025 }
1026
1027 /**
1028  * Converts numbers like 10M into bytes.
1029  *
1030  * @param string $size The size to be converted
1031  * @return int
1032  */
1033 function get_real_size($size = 0) {
1034     if (!$size) {
1035         return 0;
1036     }
1037     $scan = array();
1038     $scan['GB'] = 1073741824;
1039     $scan['Gb'] = 1073741824;
1040     $scan['G'] = 1073741824;
1041     $scan['MB'] = 1048576;
1042     $scan['Mb'] = 1048576;
1043     $scan['M'] = 1048576;
1044     $scan['m'] = 1048576;
1045     $scan['KB'] = 1024;
1046     $scan['Kb'] = 1024;
1047     $scan['K'] = 1024;
1048     $scan['k'] = 1024;
1049
1050     while (list($key) = each($scan)) {
1051         if ((strlen($size)>strlen($key))&&(substr($size, strlen($size) - strlen($key))==$key)) {
1052             $size = substr($size, 0, strlen($size) - strlen($key)) * $scan[$key];
1053             break;
1054         }
1055     }
1056     return $size;
1057 }
1058
1059 /**
1060  * Try to disable all output buffering and purge
1061  * all headers.
1062  *
1063  * @access private to be called only from lib/setup.php !
1064  * @return void
1065  */
1066 function disable_output_buffering() {
1067     $olddebug = error_reporting(0);
1068
1069     // disable compression, it would prevent closing of buffers
1070     if (ini_get_bool('zlib.output_compression')) {
1071         ini_set('zlib.output_compression', 'Off');
1072     }
1073
1074     // try to flush everything all the time
1075     ob_implicit_flush(true);
1076
1077     // close all buffers if possible and discard any existing output
1078     // this can actually work around some whitespace problems in config.php
1079     while(ob_get_level()) {
1080         if (!ob_end_clean()) {
1081             // prevent infinite loop when buffer can not be closed
1082             break;
1083         }
1084     }
1085
1086     // disable any other output handlers
1087     ini_set('output_handler', '');
1088
1089     error_reporting($olddebug);
1090 }
1091
1092 /**
1093  * Check whether a major upgrade is needed. That is defined as an upgrade that
1094  * changes something really fundamental in the database, so nothing can possibly
1095  * work until the database has been updated, and that is defined by the hard-coded
1096  * version number in this function.
1097  */
1098 function redirect_if_major_upgrade_required() {
1099     global $CFG;
1100     $lastmajordbchanges = 2012051700;
1101     if (empty($CFG->version) or (int)$CFG->version < $lastmajordbchanges or
1102             during_initial_install() or !empty($CFG->adminsetuppending)) {
1103         try {
1104             @session_get_instance()->terminate_current();
1105         } catch (Exception $e) {
1106             // Ignore any errors, redirect to upgrade anyway.
1107         }
1108         $url = $CFG->wwwroot . '/' . $CFG->admin . '/index.php';
1109         @header($_SERVER['SERVER_PROTOCOL'] . ' 303 See Other');
1110         @header('Location: ' . $url);
1111         echo bootstrap_renderer::plain_redirect_message(htmlspecialchars($url));
1112         exit;
1113     }
1114 }
1115
1116 /**
1117  * Function to check if a directory exists and by default create it if not exists.
1118  *
1119  * Previously this was accepting paths only from dataroot, but we now allow
1120  * files outside of dataroot if you supply custom paths for some settings in config.php.
1121  * This function does not verify that the directory is writable.
1122  *
1123  * NOTE: this function uses current file stat cache,
1124  *       please use clearstatcache() before this if you expect that the
1125  *       directories may have been removed recently from a different request.
1126  *
1127  * @param string $dir absolute directory path
1128  * @param boolean $create directory if does not exist
1129  * @param boolean $recursive create directory recursively
1130  * @return boolean true if directory exists or created, false otherwise
1131  */
1132 function check_dir_exists($dir, $create = true, $recursive = true) {
1133     global $CFG;
1134
1135     umask(0000); // just in case some evil code changed it
1136
1137     if (is_dir($dir)) {
1138         return true;
1139     }
1140
1141     if (!$create) {
1142         return false;
1143     }
1144
1145     return mkdir($dir, $CFG->directorypermissions, $recursive);
1146 }
1147
1148 /**
1149  * Create a directory and make sure it is writable.
1150  *
1151  * @private
1152  * @param string $dir  the full path of the directory to be created
1153  * @param bool $exceptiononerror throw exception if error encountered
1154  * @return string|false Returns full path to directory if successful, false if not; may throw exception
1155  */
1156 function make_writable_directory($dir, $exceptiononerror = true) {
1157     global $CFG;
1158
1159     if (file_exists($dir) and !is_dir($dir)) {
1160         if ($exceptiononerror) {
1161             throw new coding_exception($dir.' directory can not be created, file with the same name already exists.');
1162         } else {
1163             return false;
1164         }
1165     }
1166
1167     umask(0000); // just in case some evil code changed it
1168
1169     if (!file_exists($dir)) {
1170         if (!mkdir($dir, $CFG->directorypermissions, true)) {
1171             if ($exceptiononerror) {
1172                 throw new invalid_dataroot_permissions($dir.' can not be created, check permissions.');
1173             } else {
1174                 return false;
1175             }
1176         }
1177     }
1178
1179     if (!is_writable($dir)) {
1180         if ($exceptiononerror) {
1181             throw new invalid_dataroot_permissions($dir.' is not writable, check permissions.');
1182         } else {
1183             return false;
1184         }
1185     }
1186
1187     return $dir;
1188 }
1189
1190 /**
1191  * Protect a directory from web access.
1192  * Could be extended in the future to support other mechanisms (e.g. other webservers).
1193  *
1194  * @private
1195  * @param string $dir  the full path of the directory to be protected
1196  */
1197 function protect_directory($dir) {
1198     // Make sure a .htaccess file is here, JUST IN CASE the files area is in the open and .htaccess is supported
1199     if (!file_exists("$dir/.htaccess")) {
1200         if ($handle = fopen("$dir/.htaccess", 'w')) {   // For safety
1201             @fwrite($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");
1202             @fclose($handle);
1203         }
1204     }
1205 }
1206
1207 /**
1208  * Create a directory under dataroot and make sure it is writable.
1209  * Do not use for temporary and cache files - see make_temp_directory() and make_cache_directory().
1210  *
1211  * @param string $directory  the full path of the directory to be created under $CFG->dataroot
1212  * @param bool $exceptiononerror throw exception if error encountered
1213  * @return string|false Returns full path to directory if successful, false if not; may throw exception
1214  */
1215 function make_upload_directory($directory, $exceptiononerror = true) {
1216     global $CFG;
1217
1218     if (strpos($directory, 'temp/') === 0 or $directory === 'temp') {
1219         debugging('Use make_temp_directory() for creation of temporary directory and $CFG->tempdir to get the location.');
1220
1221     } else if (strpos($directory, 'cache/') === 0 or $directory === 'cache') {
1222         debugging('Use make_cache_directory() for creation of chache directory and $CFG->cachedir to get the location.');
1223     }
1224
1225     protect_directory($CFG->dataroot);
1226     return make_writable_directory("$CFG->dataroot/$directory", $exceptiononerror);
1227 }
1228
1229 /**
1230  * Create a directory under tempdir and make sure it is writable.
1231  * Temporary files should be used during the current request only!
1232  *
1233  * @param string $directory  the full path of the directory to be created under $CFG->tempdir
1234  * @param bool $exceptiononerror throw exception if error encountered
1235  * @return string|false Returns full path to directory if successful, false if not; may throw exception
1236  */
1237 function make_temp_directory($directory, $exceptiononerror = true) {
1238     global $CFG;
1239     if ($CFG->tempdir !== "$CFG->dataroot/temp") {
1240         check_dir_exists($CFG->tempdir, true, true);
1241         protect_directory($CFG->tempdir);
1242     } else {
1243         protect_directory($CFG->dataroot);
1244     }
1245     return make_writable_directory("$CFG->tempdir/$directory", $exceptiononerror);
1246 }
1247
1248 /**
1249  * Create a directory under cachedir and make sure it is writable.
1250  *
1251  * @param string $directory  the full path of the directory to be created under $CFG->cachedir
1252  * @param bool $exceptiononerror throw exception if error encountered
1253  * @return string|false Returns full path to directory if successful, false if not; may throw exception
1254  */
1255 function make_cache_directory($directory, $exceptiononerror = true) {
1256     global $CFG;
1257     if ($CFG->cachedir !== "$CFG->dataroot/cache") {
1258         check_dir_exists($CFG->cachedir, true, true);
1259         protect_directory($CFG->cachedir);
1260     } else {
1261         protect_directory($CFG->dataroot);
1262     }
1263     return make_writable_directory("$CFG->cachedir/$directory", $exceptiononerror);
1264 }
1265
1266
1267 /**
1268  * Initialises an Memcached instance
1269  * @global memcached $MCACHE
1270  * @return boolean Returns true if an mcached instance could be successfully initialised
1271  */
1272 function init_memcached() {
1273     global $CFG, $MCACHE;
1274
1275     include_once($CFG->libdir . '/memcached.class.php');
1276     $MCACHE = new memcached;
1277     if ($MCACHE->status()) {
1278         return true;
1279     }
1280     unset($MCACHE);
1281     return false;
1282 }
1283
1284 /**
1285  * Initialises an eAccelerator instance
1286  * @global eaccelerator $MCACHE
1287  * @return boolean Returns true if an eAccelerator instance could be successfully initialised
1288  */
1289 function init_eaccelerator() {
1290     global $CFG, $MCACHE;
1291
1292     include_once($CFG->libdir . '/eaccelerator.class.php');
1293     $MCACHE = new eaccelerator;
1294     if ($MCACHE->status()) {
1295         return true;
1296     }
1297     unset($MCACHE);
1298     return false;
1299 }
1300
1301 /**
1302  * Checks if current user is a web crawler.
1303  *
1304  * This list can not be made complete, this is not a security
1305  * restriction, we make the list only to help these sites
1306  * especially when automatic guest login is disabled.
1307  *
1308  * If admin needs security they should enable forcelogin
1309  * and disable guest access!!
1310  *
1311  * @return bool
1312  */
1313 function is_web_crawler() {
1314     if (!empty($_SERVER['HTTP_USER_AGENT'])) {
1315         if (strpos($_SERVER['HTTP_USER_AGENT'], 'Googlebot') !== false ) {
1316             return true;
1317         } else if (strpos($_SERVER['HTTP_USER_AGENT'], 'google.com') !== false ) { // Google
1318             return true;
1319         } else if (strpos($_SERVER['HTTP_USER_AGENT'], 'Yahoo! Slurp') !== false ) {  // Yahoo
1320             return true;
1321         } else if (strpos($_SERVER['HTTP_USER_AGENT'], '[ZSEBOT]') !== false ) {  // Zoomspider
1322             return true;
1323         } else if (strpos($_SERVER['HTTP_USER_AGENT'], 'MSNBOT') !== false ) {  // MSN Search
1324             return true;
1325         } else if (strpos($_SERVER['HTTP_USER_AGENT'], 'Yandex') !== false ) {
1326             return true;
1327         } else if (strpos($_SERVER['HTTP_USER_AGENT'], 'AltaVista') !== false ) {
1328             return true;
1329         }
1330     }
1331     return false;
1332 }
1333
1334 /**
1335  * This class solves the problem of how to initialise $OUTPUT.
1336  *
1337  * The problem is caused be two factors
1338  * <ol>
1339  * <li>On the one hand, we cannot be sure when output will start. In particular,
1340  * an error, which needs to be displayed, could be thrown at any time.</li>
1341  * <li>On the other hand, we cannot be sure when we will have all the information
1342  * necessary to correctly initialise $OUTPUT. $OUTPUT depends on the theme, which
1343  * (potentially) depends on the current course, course categories, and logged in user.
1344  * It also depends on whether the current page requires HTTPS.</li>
1345  * </ol>
1346  *
1347  * So, it is hard to find a single natural place during Moodle script execution,
1348  * which we can guarantee is the right time to initialise $OUTPUT. Instead we
1349  * adopt the following strategy
1350  * <ol>
1351  * <li>We will initialise $OUTPUT the first time it is used.</li>
1352  * <li>If, after $OUTPUT has been initialised, the script tries to change something
1353  * that $OUTPUT depends on, we throw an exception making it clear that the script
1354  * did something wrong.
1355  * </ol>
1356  *
1357  * The only problem with that is, how do we initialise $OUTPUT on first use if,
1358  * it is going to be used like $OUTPUT->somthing(...)? Well that is where this
1359  * class comes in. Initially, we set up $OUTPUT = new bootstrap_renderer(). Then,
1360  * when any method is called on that object, we initialise $OUTPUT, and pass the call on.
1361  *
1362  * Note that this class is used before lib/outputlib.php has been loaded, so we
1363  * must be careful referring to classes/functions from there, they may not be
1364  * defined yet, and we must avoid fatal errors.
1365  *
1366  * @copyright 2009 Tim Hunt
1367  * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
1368  * @since     Moodle 2.0
1369  */
1370 class bootstrap_renderer {
1371     /**
1372      * Handles re-entrancy. Without this, errors or debugging output that occur
1373      * during the initialisation of $OUTPUT, cause infinite recursion.
1374      * @var boolean
1375      */
1376     protected $initialising = false;
1377
1378     /**
1379      * Have we started output yet?
1380      * @return boolean true if the header has been printed.
1381      */
1382     public function has_started() {
1383         return false;
1384     }
1385
1386     /**
1387      * Constructor - to be used by core code only.
1388      * @param string $method The method to call
1389      * @param array $arguments Arguments to pass to the method being called
1390      * @return string
1391      */
1392     public function __call($method, $arguments) {
1393         global $OUTPUT, $PAGE;
1394
1395         $recursing = false;
1396         if ($method == 'notification') {
1397             // Catch infinite recursion caused by debugging output during print_header.
1398             $backtrace = debug_backtrace();
1399             array_shift($backtrace);
1400             array_shift($backtrace);
1401             $recursing = is_early_init($backtrace);
1402         }
1403
1404         $earlymethods = array(
1405             'fatal_error' => 'early_error',
1406             'notification' => 'early_notification',
1407         );
1408
1409         // If lib/outputlib.php has been loaded, call it.
1410         if (!empty($PAGE) && !$recursing) {
1411             if (array_key_exists($method, $earlymethods)) {
1412                 //prevent PAGE->context warnings - exceptions might appear before we set any context
1413                 $PAGE->set_context(null);
1414             }
1415             $PAGE->initialise_theme_and_output();
1416             return call_user_func_array(array($OUTPUT, $method), $arguments);
1417         }
1418
1419         $this->initialising = true;
1420
1421         // Too soon to initialise $OUTPUT, provide a couple of key methods.
1422         if (array_key_exists($method, $earlymethods)) {
1423             return call_user_func_array(array('bootstrap_renderer', $earlymethods[$method]), $arguments);
1424         }
1425
1426         throw new coding_exception('Attempt to start output before enough information is known to initialise the theme.');
1427     }
1428
1429     /**
1430      * Returns nicely formatted error message in a div box.
1431      * @static
1432      * @param string $message error message
1433      * @param string $moreinfourl (ignored in early errors)
1434      * @param string $link (ignored in early errors)
1435      * @param array $backtrace
1436      * @param string $debuginfo
1437      * @return string
1438      */
1439     public static function early_error_content($message, $moreinfourl, $link, $backtrace, $debuginfo = null) {
1440         global $CFG;
1441
1442         $content = '<div style="margin-top: 6em; margin-left:auto; margin-right:auto; color:#990000; text-align:center; font-size:large; border-width:1px;
1443 border-color:black; background-color:#ffffee; border-style:solid; border-radius: 20px; border-collapse: collapse;
1444 width: 80%; -moz-border-radius: 20px; padding: 15px">
1445 ' . $message . '
1446 </div>';
1447         if (!empty($CFG->debug) && $CFG->debug >= DEBUG_DEVELOPER) {
1448             if (!empty($debuginfo)) {
1449                 $debuginfo = s($debuginfo); // removes all nasty JS
1450                 $debuginfo = str_replace("\n", '<br />', $debuginfo); // keep newlines
1451                 $content .= '<div class="notifytiny">Debug info: ' . $debuginfo . '</div>';
1452             }
1453             if (!empty($backtrace)) {
1454                 $content .= '<div class="notifytiny">Stack trace: ' . format_backtrace($backtrace, false) . '</div>';
1455             }
1456         }
1457
1458         return $content;
1459     }
1460
1461     /**
1462      * This function should only be called by this class, or from exception handlers
1463      * @static
1464      * @param string $message error message
1465      * @param string $moreinfourl (ignored in early errors)
1466      * @param string $link (ignored in early errors)
1467      * @param array $backtrace
1468      * @param string $debuginfo extra information for developers
1469      * @return string
1470      */
1471     public static function early_error($message, $moreinfourl, $link, $backtrace, $debuginfo = null) {
1472         global $CFG;
1473
1474         if (CLI_SCRIPT) {
1475             echo "!!! $message !!!\n";
1476             if (!empty($CFG->debug) and $CFG->debug >= DEBUG_DEVELOPER) {
1477                 if (!empty($debuginfo)) {
1478                     echo "\nDebug info: $debuginfo";
1479                 }
1480                 if (!empty($backtrace)) {
1481                     echo "\nStack trace: " . format_backtrace($backtrace, true);
1482                 }
1483             }
1484             return;
1485
1486         } else if (AJAX_SCRIPT) {
1487             $e = new stdClass();
1488             $e->error      = $message;
1489             $e->stacktrace = NULL;
1490             $e->debuginfo  = NULL;
1491             if (!empty($CFG->debug) and $CFG->debug >= DEBUG_DEVELOPER) {
1492                 if (!empty($debuginfo)) {
1493                     $e->debuginfo = $debuginfo;
1494                 }
1495                 if (!empty($backtrace)) {
1496                     $e->stacktrace = format_backtrace($backtrace, true);
1497                 }
1498             }
1499             @header('Content-Type: application/json; charset=utf-8');
1500             echo json_encode($e);
1501             return;
1502         }
1503
1504         // In the name of protocol correctness, monitoring and performance
1505         // profiling, set the appropriate error headers for machine consumption
1506         if (isset($_SERVER['SERVER_PROTOCOL'])) {
1507             // Avoid it with cron.php. Note that we assume it's HTTP/1.x
1508             // The 503 ode here means our Moodle does not work at all, the error happened too early
1509             @header($_SERVER['SERVER_PROTOCOL'] . ' 503 Service Unavailable');
1510         }
1511
1512         // better disable any caching
1513         @header('Content-Type: text/html; charset=utf-8');
1514         @header('Cache-Control: no-store, no-cache, must-revalidate');
1515         @header('Cache-Control: post-check=0, pre-check=0', false);
1516         @header('Pragma: no-cache');
1517         @header('Expires: Mon, 20 Aug 1969 09:23:00 GMT');
1518         @header('Last-Modified: ' . gmdate('D, d M Y H:i:s') . ' GMT');
1519
1520         if (function_exists('get_string')) {
1521             $strerror = get_string('error');
1522         } else {
1523             $strerror = 'Error';
1524         }
1525
1526         $content = self::early_error_content($message, $moreinfourl, $link, $backtrace, $debuginfo);
1527
1528         return self::plain_page($strerror, $content);
1529     }
1530
1531     /**
1532      * Early notification message
1533      * @static
1534      * @param string $message
1535      * @param string $classes usually notifyproblem or notifysuccess
1536      * @return string
1537      */
1538     public static function early_notification($message, $classes = 'notifyproblem') {
1539         return '<div class="' . $classes . '">' . $message . '</div>';
1540     }
1541
1542     /**
1543      * Page should redirect message.
1544      * @static
1545      * @param string $encodedurl redirect url
1546      * @return string
1547      */
1548     public static function plain_redirect_message($encodedurl) {
1549         $message = '<div style="margin-top: 3em; margin-left:auto; margin-right:auto; text-align:center;">' . get_string('pageshouldredirect') . '<br /><a href="'.
1550                 $encodedurl .'">'. get_string('continue') .'</a></div>';
1551         return self::plain_page(get_string('redirect'), $message);
1552     }
1553
1554     /**
1555      * Early redirection page, used before full init of $PAGE global
1556      * @static
1557      * @param string $encodedurl redirect url
1558      * @param string $message redirect message
1559      * @param int $delay time in seconds
1560      * @return string redirect page
1561      */
1562     public static function early_redirect_message($encodedurl, $message, $delay) {
1563         $meta = '<meta http-equiv="refresh" content="'. $delay .'; url='. $encodedurl .'" />';
1564         $content = self::early_error_content($message, null, null, null);
1565         $content .= self::plain_redirect_message($encodedurl);
1566
1567         return self::plain_page(get_string('redirect'), $content, $meta);
1568     }
1569
1570     /**
1571      * Output basic html page.
1572      * @static
1573      * @param string $title page title
1574      * @param string $content page content
1575      * @param string $meta meta tag
1576      * @return string html page
1577      */
1578     protected static function plain_page($title, $content, $meta = '') {
1579         if (function_exists('get_string') && function_exists('get_html_lang')) {
1580             $htmllang = get_html_lang();
1581         } else {
1582             $htmllang = '';
1583         }
1584
1585         return '<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
1586 <html xmlns="http://www.w3.org/1999/xhtml" ' . $htmllang . '>
1587 <head>
1588 <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
1589 '.$meta.'
1590 <title>' . $title . '</title>
1591 </head><body>' . $content . '</body></html>';
1592     }
1593 }