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See Release Notes

  • Bug fixes for general core bugs in 3.11.x will end 14 Nov 2022 (12 months plus 6 months extension).
  • Bug fixes for security issues in 3.11.x will end 13 Nov 2023 (18 months plus 12 months extension).
  • PHP version: minimum PHP 7.3.0 Note: minimum PHP version has increased since Moodle 3.10. PHP 7.4.x is supported too.
/lib/ -> setuplib.php (source)

Differences Between: [Versions 310 and 311] [Versions 311 and 400] [Versions 311 and 401] [Versions 38 and 311] [Versions 39 and 311]

   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   * Base Moodle Exception class
  56   *
  57   * Although this class is defined here, you cannot throw a moodle_exception until
  58   * after moodlelib.php has been included (which will happen very soon).
  59   *
  60   * @package    core
  61   * @subpackage lib
  62   * @copyright  2008 Petr Skoda  {@link http://skodak.org}
  63   * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  64   */
  65  class moodle_exception extends Exception {
  66  
  67      /**
  68       * @var string The name of the string from error.php to print
  69       */
  70      public $errorcode;
  71  
  72      /**
  73       * @var string The name of module
  74       */
  75      public $module;
  76  
  77      /**
  78       * @var mixed Extra words and phrases that might be required in the error string
  79       */
  80      public $a;
  81  
  82      /**
  83       * @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.
  84       */
  85      public $link;
  86  
  87      /**
  88       * @var string Optional information to aid the debugging process
  89       */
  90      public $debuginfo;
  91  
  92      /**
  93       * Constructor
  94       * @param string $errorcode The name of the string from error.php to print
  95       * @param string $module name of module
  96       * @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.
  97       * @param mixed $a Extra words and phrases that might be required in the error string
  98       * @param string $debuginfo optional debugging information
  99       */
 100      function __construct($errorcode, $module='', $link='', $a=NULL, $debuginfo=null) {
 101          global $CFG;
 102  
 103          if (empty($module) || $module == 'moodle' || $module == 'core') {
 104              $module = 'error';
 105          }
 106  
 107          $this->errorcode = $errorcode;
 108          $this->module    = $module;
 109          $this->link      = $link;
 110          $this->a         = $a;
 111          $this->debuginfo = is_null($debuginfo) ? null : (string)$debuginfo;
 112  
 113          if (get_string_manager()->string_exists($errorcode, $module)) {
 114              $message = get_string($errorcode, $module, $a);
 115              $haserrorstring = true;
 116          } else {
 117              $message = $module . '/' . $errorcode;
 118              $haserrorstring = false;
 119          }
 120  
 121          $isinphpunittest = (defined('PHPUNIT_TEST') && PHPUNIT_TEST);
 122          $hasdebugdeveloper = (
 123              isset($CFG->debugdisplay) &&
 124              isset($CFG->debug) &&
 125              $CFG->debugdisplay &&
 126              $CFG->debug === DEBUG_DEVELOPER
 127          );
 128  
 129          if ($debuginfo) {
 130              if ($isinphpunittest || $hasdebugdeveloper) {
 131                  $message = "$message ($debuginfo)";
 132              }
 133          }
 134  
 135          if (!$haserrorstring and $isinphpunittest) {
 136              // Append the contents of $a to $debuginfo so helpful information isn't lost.
 137              // This emulates what {@link get_exception_info()} does. Unfortunately that
 138              // function is not used by phpunit.
 139              $message .= PHP_EOL.'$a contents: '.print_r($a, true);
 140          }
 141  
 142          parent::__construct($message, 0);
 143      }
 144  }
 145  
 146  /**
 147   * Course/activity access exception.
 148   *
 149   * This exception is thrown from require_login()
 150   *
 151   * @package    core_access
 152   * @copyright  2010 Petr Skoda  {@link http://skodak.org}
 153   * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 154   */
 155  class require_login_exception extends moodle_exception {
 156      /**
 157       * Constructor
 158       * @param string $debuginfo Information to aid the debugging process
 159       */
 160      function __construct($debuginfo) {
 161          parent::__construct('requireloginerror', 'error', '', NULL, $debuginfo);
 162      }
 163  }
 164  
 165  /**
 166   * Session timeout exception.
 167   *
 168   * This exception is thrown from require_login()
 169   *
 170   * @package    core_access
 171   * @copyright  2015 Andrew Nicols <andrew@nicols.co.uk>
 172   * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 173   */
 174  class require_login_session_timeout_exception extends require_login_exception {
 175      /**
 176       * Constructor
 177       */
 178      public function __construct() {
 179          moodle_exception::__construct('sessionerroruser', 'error');
 180      }
 181  }
 182  
 183  /**
 184   * Web service parameter exception class
 185   * @deprecated since Moodle 2.2 - use moodle exception instead
 186   * This exception must be thrown to the web service client when a web service parameter is invalid
 187   * The error string is gotten from webservice.php
 188   */
 189  class webservice_parameter_exception extends moodle_exception {
 190      /**
 191       * Constructor
 192       * @param string $errorcode The name of the string from webservice.php to print
 193       * @param string $a The name of the parameter
 194       * @param string $debuginfo Optional information to aid debugging
 195       */
 196      function __construct($errorcode=null, $a = '', $debuginfo = null) {
 197          parent::__construct($errorcode, 'webservice', '', $a, $debuginfo);
 198      }
 199  }
 200  
 201  /**
 202   * Exceptions indicating user does not have permissions to do something
 203   * and the execution can not continue.
 204   *
 205   * @package    core_access
 206   * @copyright  2009 Petr Skoda  {@link http://skodak.org}
 207   * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 208   */
 209  class required_capability_exception extends moodle_exception {
 210      /**
 211       * Constructor
 212       * @param context $context The context used for the capability check
 213       * @param string $capability The required capability
 214       * @param string $errormessage The error message to show the user
 215       * @param string $stringfile
 216       */
 217      function __construct($context, $capability, $errormessage, $stringfile) {
 218          $capabilityname = get_capability_string($capability);
 219          if ($context->contextlevel == CONTEXT_MODULE and preg_match('/:view$/', $capability)) {
 220              // 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
 221              $parentcontext = $context->get_parent_context();
 222              $link = $parentcontext->get_url();
 223          } else {
 224              $link = $context->get_url();
 225          }
 226          parent::__construct($errormessage, $stringfile, $link, $capabilityname);
 227      }
 228  }
 229  
 230  /**
 231   * Exception indicating programming error, must be fixed by a programer. For example
 232   * a core API might throw this type of exception if a plugin calls it incorrectly.
 233   *
 234   * @package    core
 235   * @subpackage lib
 236   * @copyright  2008 Petr Skoda  {@link http://skodak.org}
 237   * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 238   */
 239  class coding_exception extends moodle_exception {
 240      /**
 241       * Constructor
 242       * @param string $hint short description of problem
 243       * @param string $debuginfo detailed information how to fix problem
 244       */
 245      function __construct($hint, $debuginfo=null) {
 246          parent::__construct('codingerror', 'debug', '', $hint, $debuginfo);
 247      }
 248  }
 249  
 250  /**
 251   * Exception indicating malformed parameter problem.
 252   * This exception is not supposed to be thrown when processing
 253   * user submitted data in forms. It is more suitable
 254   * for WS and other low level stuff.
 255   *
 256   * @package    core
 257   * @subpackage lib
 258   * @copyright  2009 Petr Skoda  {@link http://skodak.org}
 259   * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 260   */
 261  class invalid_parameter_exception extends moodle_exception {
 262      /**
 263       * Constructor
 264       * @param string $debuginfo some detailed information
 265       */
 266      function __construct($debuginfo=null) {
 267          parent::__construct('invalidparameter', 'debug', '', null, $debuginfo);
 268      }
 269  }
 270  
 271  /**
 272   * Exception indicating malformed response problem.
 273   * This exception is not supposed to be thrown when processing
 274   * user submitted data in forms. It is more suitable
 275   * for WS and other low level stuff.
 276   */
 277  class invalid_response_exception extends moodle_exception {
 278      /**
 279       * Constructor
 280       * @param string $debuginfo some detailed information
 281       */
 282      function __construct($debuginfo=null) {
 283          parent::__construct('invalidresponse', 'debug', '', null, $debuginfo);
 284      }
 285  }
 286  
 287  /**
 288   * An exception that indicates something really weird happened. For example,
 289   * if you do switch ($context->contextlevel), and have one case for each
 290   * CONTEXT_... constant. You might throw an invalid_state_exception in the
 291   * default case, to just in case something really weird is going on, and
 292   * $context->contextlevel is invalid - rather than ignoring this possibility.
 293   *
 294   * @package    core
 295   * @subpackage lib
 296   * @copyright  2009 onwards Martin Dougiamas  {@link http://moodle.com}
 297   * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 298   */
 299  class invalid_state_exception extends moodle_exception {
 300      /**
 301       * Constructor
 302       * @param string $hint short description of problem
 303       * @param string $debuginfo optional more detailed information
 304       */
 305      function __construct($hint, $debuginfo=null) {
 306          parent::__construct('invalidstatedetected', 'debug', '', $hint, $debuginfo);
 307      }
 308  }
 309  
 310  /**
 311   * An exception that indicates incorrect permissions in $CFG->dataroot
 312   *
 313   * @package    core
 314   * @subpackage lib
 315   * @copyright  2010 Petr Skoda {@link http://skodak.org}
 316   * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 317   */
 318  class invalid_dataroot_permissions extends moodle_exception {
 319      /**
 320       * Constructor
 321       * @param string $debuginfo optional more detailed information
 322       */
 323      function __construct($debuginfo = NULL) {
 324          parent::__construct('invaliddatarootpermissions', 'error', '', NULL, $debuginfo);
 325      }
 326  }
 327  
 328  /**
 329   * An exception that indicates that file can not be served
 330   *
 331   * @package    core
 332   * @subpackage lib
 333   * @copyright  2010 Petr Skoda {@link http://skodak.org}
 334   * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 335   */
 336  class file_serving_exception extends moodle_exception {
 337      /**
 338       * Constructor
 339       * @param string $debuginfo optional more detailed information
 340       */
 341      function __construct($debuginfo = NULL) {
 342          parent::__construct('cannotservefile', 'error', '', NULL, $debuginfo);
 343      }
 344  }
 345  
 346  /**
 347   * Default exception handler.
 348   *
 349   * @param Exception $ex
 350   * @return void -does not return. Terminates execution!
 351   */
 352  function default_exception_handler($ex) {
 353      global $CFG, $DB, $OUTPUT, $USER, $FULLME, $SESSION, $PAGE;
 354  
 355      // detect active db transactions, rollback and log as error
 356      abort_all_db_transactions();
 357  
 358      if (($ex instanceof required_capability_exception) && !CLI_SCRIPT && !AJAX_SCRIPT && !empty($CFG->autologinguests) && !empty($USER->autologinguest)) {
 359          $SESSION->wantsurl = qualified_me();
 360          redirect(get_login_url());
 361      }
 362  
 363      $info = get_exception_info($ex);
 364  
 365      // If we already tried to send the header remove it, the content length
 366      // should be either empty or the length of the error page.
 367      @header_remove('Content-Length');
 368  
 369      if (is_early_init($info->backtrace)) {
 370          echo bootstrap_renderer::early_error($info->message, $info->moreinfourl, $info->link, $info->backtrace, $info->debuginfo, $info->errorcode);
 371      } else {
 372          if (debugging('', DEBUG_MINIMAL)) {
 373              $logerrmsg = "Default exception handler: ".$info->message.' Debug: '.$info->debuginfo."\n".format_backtrace($info->backtrace, true);
 374              error_log($logerrmsg);
 375          }
 376  
 377          try {
 378              if ($DB) {
 379                  // If you enable db debugging and exception is thrown, the print footer prints a lot of rubbish
 380                  $DB->set_debug(0);
 381              }
 382              if (AJAX_SCRIPT) {
 383                  // If we are in an AJAX script we don't want to use PREFERRED_RENDERER_TARGET.
 384                  // Because we know we will want to use ajax format.
 385                  $renderer = new core_renderer_ajax($PAGE, 'ajax');
 386              } else {
 387                  $renderer = $OUTPUT;
 388              }
 389              echo $renderer->fatal_error($info->message, $info->moreinfourl, $info->link, $info->backtrace, $info->debuginfo,
 390                  $info->errorcode);
 391          } catch (Exception $e) {
 392              $out_ex = $e;
 393          } catch (Throwable $e) {
 394              // Engine errors in PHP7 throw exceptions of type Throwable (this "catch" will be ignored in PHP5).
 395              $out_ex = $e;
 396          }
 397  
 398          if (isset($out_ex)) {
 399              // default exception handler MUST not throw any exceptions!!
 400              // 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
 401              // so we just print at least something instead of "Exception thrown without a stack frame in Unknown on line 0":-(
 402              if (CLI_SCRIPT or AJAX_SCRIPT) {
 403                  // just ignore the error and send something back using the safest method
 404                  echo bootstrap_renderer::early_error($info->message, $info->moreinfourl, $info->link, $info->backtrace, $info->debuginfo, $info->errorcode);
 405              } else {
 406                  echo bootstrap_renderer::early_error_content($info->message, $info->moreinfourl, $info->link, $info->backtrace, $info->debuginfo);
 407                  $outinfo = get_exception_info($out_ex);
 408                  echo bootstrap_renderer::early_error_content($outinfo->message, $outinfo->moreinfourl, $outinfo->link, $outinfo->backtrace, $outinfo->debuginfo);
 409              }
 410          }
 411      }
 412  
 413      exit(1); // General error code
 414  }
 415  
 416  /**
 417   * Default error handler, prevents some white screens.
 418   * @param int $errno
 419   * @param string $errstr
 420   * @param string $errfile
 421   * @param int $errline
 422   * @return bool false means use default error handler
 423   */
 424  function default_error_handler($errno, $errstr, $errfile, $errline) {
 425      if ($errno == 4096) {
 426          //fatal catchable error
 427          throw new coding_exception('PHP catchable fatal error', $errstr);
 428      }
 429      return false;
 430  }
 431  
 432  /**
 433   * Unconditionally abort all database transactions, this function
 434   * should be called from exception handlers only.
 435   * @return void
 436   */
 437  function abort_all_db_transactions() {
 438      global $CFG, $DB, $SCRIPT;
 439  
 440      // default exception handler MUST not throw any exceptions!!
 441  
 442      if ($DB && $DB->is_transaction_started()) {
 443          error_log('Database transaction aborted automatically in ' . $CFG->dirroot . $SCRIPT);
 444          // note: transaction blocks should never change current $_SESSION
 445          $DB->force_transaction_rollback();
 446      }
 447  }
 448  
 449  /**
 450   * This function encapsulates the tests for whether an exception was thrown in
 451   * early init -- either during setup.php or during init of $OUTPUT.
 452   *
 453   * If another exception is thrown then, and if we do not take special measures,
 454   * we would just get a very cryptic message "Exception thrown without a stack
 455   * frame in Unknown on line 0". That makes debugging very hard, so we do take
 456   * special measures in default_exception_handler, with the help of this function.
 457   *
 458   * @param array $backtrace the stack trace to analyse.
 459   * @return boolean whether the stack trace is somewhere in output initialisation.
 460   */
 461  function is_early_init($backtrace) {
 462      $dangerouscode = array(
 463          array('function' => 'header', 'type' => '->'),
 464          array('class' => 'bootstrap_renderer'),
 465          array('file' => __DIR__.'/setup.php'),
 466      );
 467      foreach ($backtrace as $stackframe) {
 468          foreach ($dangerouscode as $pattern) {
 469              $matches = true;
 470              foreach ($pattern as $property => $value) {
 471                  if (!isset($stackframe[$property]) || $stackframe[$property] != $value) {
 472                      $matches = false;
 473                  }
 474              }
 475              if ($matches) {
 476                  return true;
 477              }
 478          }
 479      }
 480      return false;
 481  }
 482  
 483  /**
 484   * Abort execution by throwing of a general exception,
 485   * default exception handler displays the error message in most cases.
 486   *
 487   * @param string $errorcode The name of the language string containing the error message.
 488   *      Normally this should be in the error.php lang file.
 489   * @param string $module The language file to get the error message from.
 490   * @param string $link The url where the user will be prompted to continue.
 491   *      If no url is provided the user will be directed to the site index page.
 492   * @param object $a Extra words and phrases that might be required in the error string
 493   * @param string $debuginfo optional debugging information
 494   * @return void, always throws exception!
 495   */
 496  function print_error($errorcode, $module = 'error', $link = '', $a = null, $debuginfo = null) {
 497      throw new moodle_exception($errorcode, $module, $link, $a, $debuginfo);
 498  }
 499  
 500  /**
 501   * Returns detailed information about specified exception.
 502   * @param exception $ex
 503   * @return object
 504   */
 505  function get_exception_info($ex) {
 506      global $CFG, $DB, $SESSION;
 507  
 508      if ($ex instanceof moodle_exception) {
 509          $errorcode = $ex->errorcode;
 510          $module = $ex->module;
 511          $a = $ex->a;
 512          $link = $ex->link;
 513          $debuginfo = $ex->debuginfo;
 514      } else {
 515          $errorcode = 'generalexceptionmessage';
 516          $module = 'error';
 517          $a = $ex->getMessage();
 518          $link = '';
 519          $debuginfo = '';
 520      }
 521  
 522      // Append the error code to the debug info to make grepping and googling easier
 523      $debuginfo .= PHP_EOL."Error code: $errorcode";
 524  
 525      $backtrace = $ex->getTrace();
 526      $place = array('file'=>$ex->getFile(), 'line'=>$ex->getLine(), 'exception'=>get_class($ex));
 527      array_unshift($backtrace, $place);
 528  
 529      // Be careful, no guarantee moodlelib.php is loaded.
 530      if (empty($module) || $module == 'moodle' || $module == 'core') {
 531          $module = 'error';
 532      }
 533      // Search for the $errorcode's associated string
 534      // If not found, append the contents of $a to $debuginfo so helpful information isn't lost
 535      if (function_exists('get_string_manager')) {
 536          if (get_string_manager()->string_exists($errorcode, $module)) {
 537              $message = get_string($errorcode, $module, $a);
 538          } elseif ($module == 'error' && get_string_manager()->string_exists($errorcode, 'moodle')) {
 539              // Search in moodle file if error specified - needed for backwards compatibility
 540              $message = get_string($errorcode, 'moodle', $a);
 541          } else {
 542              $message = $module . '/' . $errorcode;
 543              $debuginfo .= PHP_EOL.'$a contents: '.print_r($a, true);
 544          }
 545      } else {
 546          $message = $module . '/' . $errorcode;
 547          $debuginfo .= PHP_EOL.'$a contents: '.print_r($a, true);
 548      }
 549  
 550      // Remove some absolute paths from message and debugging info.
 551      $searches = array();
 552      $replaces = array();
 553      $cfgnames = array('backuptempdir', 'tempdir', 'cachedir', 'localcachedir', 'themedir', 'dataroot', 'dirroot');
 554      foreach ($cfgnames as $cfgname) {
 555          if (property_exists($CFG, $cfgname)) {
 556              $searches[] = $CFG->$cfgname;
 557              $replaces[] = "[$cfgname]";
 558          }
 559      }
 560      if (!empty($searches)) {
 561          $message   = str_replace($searches, $replaces, $message);
 562          $debuginfo = str_replace($searches, $replaces, $debuginfo);
 563      }
 564  
 565      // Be careful, no guarantee weblib.php is loaded.
 566      if (function_exists('clean_text')) {
 567          $message = clean_text($message);
 568      } else {
 569          $message = htmlspecialchars($message);
 570      }
 571  
 572      if (!empty($CFG->errordocroot)) {
 573          $errordoclink = $CFG->errordocroot . '/en/';
 574      } else {
 575          // Only if the function is available. May be not for early errors.
 576          if (function_exists('current_language')) {
 577              $errordoclink = get_docs_url();
 578          } else {
 579              $errordoclink = 'https://docs.moodle.org/en/';
 580          }
 581      }
 582  
 583      if ($module === 'error') {
 584          $modulelink = 'moodle';
 585      } else {
 586          $modulelink = $module;
 587      }
 588      $moreinfourl = $errordoclink . 'error/' . $modulelink . '/' . $errorcode;
 589  
 590      if (empty($link)) {
 591          $link = get_local_referer(false) ?: ($CFG->wwwroot . '/');
 592      }
 593  
 594      // When printing an error the continue button should never link offsite.
 595      // We cannot use clean_param() here as it is not guaranteed that it has been loaded yet.
 596      if (stripos($link, $CFG->wwwroot) === 0) {
 597          // Internal HTTP, all good.
 598      } else {
 599          // External link spotted!
 600          $link = $CFG->wwwroot . '/';
 601      }
 602  
 603      $info = new stdClass();
 604      $info->message     = $message;
 605      $info->errorcode   = $errorcode;
 606      $info->backtrace   = $backtrace;
 607      $info->link        = $link;
 608      $info->moreinfourl = $moreinfourl;
 609      $info->a           = $a;
 610      $info->debuginfo   = $debuginfo;
 611  
 612      return $info;
 613  }
 614  
 615  /**
 616   * Generate a V4 UUID.
 617   *
 618   * Unique is hard. Very hard. Attempt to use the PECL UUID function if available, and if not then revert to
 619   * constructing the uuid using mt_rand.
 620   *
 621   * It is important that this token is not solely based on time as this could lead
 622   * to duplicates in a clustered environment (especially on VMs due to poor time precision).
 623   *
 624   * @see https://tools.ietf.org/html/rfc4122
 625   *
 626   * @deprecated since Moodle 3.8 MDL-61038 - please do not use this function any more.
 627   * @see \core\uuid::generate()
 628   *
 629   * @return string The uuid.
 630   */
 631  function generate_uuid() {
 632      debugging('generate_uuid() is deprecated. Please use \core\uuid::generate() instead.', DEBUG_DEVELOPER);
 633      return \core\uuid::generate();
 634  }
 635  
 636  /**
 637   * Returns the Moodle Docs URL in the users language for a given 'More help' link.
 638   *
 639   * There are three cases:
 640   *
 641   * 1. In the normal case, $path will be a short relative path 'component/thing',
 642   * like 'mod/folder/view' 'group/import'. This gets turned into an link to
 643   * MoodleDocs in the user's language, and for the appropriate Moodle version.
 644   * E.g. 'group/import' may become 'http://docs.moodle.org/2x/en/group/import'.
 645   * The 'http://docs.moodle.org' bit comes from $CFG->docroot.
 646   *
 647   * This is the only option that should be used in standard Moodle code. The other
 648   * two options have been implemented because they are useful for third-party plugins.
 649   *
 650   * 2. $path may be an absolute URL, starting http:// or https://. In this case,
 651   * the link is used as is.
 652   *
 653   * 3. $path may start %%WWWROOT%%, in which case that is replaced by
 654   * $CFG->wwwroot to make the link.
 655   *
 656   * @param string $path the place to link to. See above for details.
 657   * @return string The MoodleDocs URL in the user's language. for example @link http://docs.moodle.org/2x/en/$path}
 658   */
 659  function get_docs_url($path = null) {
 660      global $CFG;
 661  
 662      // Absolute URLs are used unmodified.
 663      if (substr($path, 0, 7) === 'http://' || substr($path, 0, 8) === 'https://') {
 664          return $path;
 665      }
 666  
 667      // Paths starting %%WWWROOT%% have that replaced by $CFG->wwwroot.
 668      if (substr($path, 0, 11) === '%%WWWROOT%%') {
 669          return $CFG->wwwroot . substr($path, 11);
 670      }
 671  
 672      // Otherwise we do the normal case, and construct a MoodleDocs URL relative to $CFG->docroot.
 673  
 674      // Check that $CFG->branch has been set up, during installation it won't be.
 675      if (empty($CFG->branch)) {
 676          // It's not there yet so look at version.php.
 677          include($CFG->dirroot.'/version.php');
 678      } else {
 679          // We can use $CFG->branch and avoid having to include version.php.
 680          $branch = $CFG->branch;
 681      }
 682      // ensure branch is valid.
 683      if (!$branch) {
 684          // We should never get here but in case we do lets set $branch to .
 685          // the smart one's will know that this is the current directory
 686          // and the smarter ones will know that there is some smart matching
 687          // that will ensure people end up at the latest version of the docs.
 688          $branch = '.';
 689      }
 690      if (empty($CFG->doclang)) {
 691          $lang = current_language();
 692      } else {
 693          $lang = $CFG->doclang;
 694      }
 695      $end = '/' . $branch . '/' . $lang . '/' . $path;
 696      if (empty($CFG->docroot)) {
 697          return 'http://docs.moodle.org'. $end;
 698      } else {
 699          return $CFG->docroot . $end ;
 700      }
 701  }
 702  
 703  /**
 704   * Formats a backtrace ready for output.
 705   *
 706   * This function does not include function arguments because they could contain sensitive information
 707   * not suitable to be exposed in a response.
 708   *
 709   * @param array $callers backtrace array, as returned by debug_backtrace().
 710   * @param boolean $plaintext if false, generates HTML, if true generates plain text.
 711   * @return string formatted backtrace, ready for output.
 712   */
 713  function format_backtrace($callers, $plaintext = false) {
 714      // do not use $CFG->dirroot because it might not be available in destructors
 715      $dirroot = dirname(__DIR__);
 716  
 717      if (empty($callers)) {
 718          return '';
 719      }
 720  
 721      $from = $plaintext ? '' : '<ul style="text-align: left" data-rel="backtrace">';
 722      foreach ($callers as $caller) {
 723          if (!isset($caller['line'])) {
 724              $caller['line'] = '?'; // probably call_user_func()
 725          }
 726          if (!isset($caller['file'])) {
 727              $caller['file'] = 'unknownfile'; // probably call_user_func()
 728          }
 729          $line = $plaintext ? '* ' : '<li>';
 730          $line .= 'line ' . $caller['line'] . ' of ' . str_replace($dirroot, '', $caller['file']);
 731          if (isset($caller['function'])) {
 732              $line .= ': call to ';
 733              if (isset($caller['class'])) {
 734                  $line .= $caller['class'] . $caller['type'];
 735              }
 736              $line .= $caller['function'] . '()';
 737          } else if (isset($caller['exception'])) {
 738              $line .= ': '.$caller['exception'].' thrown';
 739          }
 740  
 741          // Remove any non printable chars.
 742          $line = preg_replace('/[[:^print:]]/', '', $line);
 743  
 744          $line .= $plaintext ? "\n" : '</li>';
 745          $from .= $line;
 746      }
 747      $from .= $plaintext ? '' : '</ul>';
 748  
 749      return $from;
 750  }
 751  
 752  /**
 753   * This function makes the return value of ini_get consistent if you are
 754   * setting server directives through the .htaccess file in apache.
 755   *
 756   * Current behavior for value set from php.ini On = 1, Off = [blank]
 757   * Current behavior for value set from .htaccess On = On, Off = Off
 758   * Contributed by jdell @ unr.edu
 759   *
 760   * @param string $ini_get_arg The argument to get
 761   * @return bool True for on false for not
 762   */
 763  function ini_get_bool($ini_get_arg) {
 764      $temp = ini_get($ini_get_arg);
 765  
 766      if ($temp == '1' or strtolower($temp) == 'on') {
 767          return true;
 768      }
 769      return false;
 770  }
 771  
 772  /**
 773   * This function verifies the sanity of PHP configuration
 774   * and stops execution if anything critical found.
 775   */
 776  function setup_validate_php_configuration() {
 777     // this must be very fast - no slow checks here!!!
 778  
 779     if (ini_get_bool('session.auto_start')) {
 780         print_error('sessionautostartwarning', 'admin');
 781     }
 782  }
 783  
 784  /**
 785   * Initialise global $CFG variable.
 786   * @private to be used only from lib/setup.php
 787   */
 788  function initialise_cfg() {
 789      global $CFG, $DB;
 790  
 791      if (!$DB) {
 792          // This should not happen.
 793          return;
 794      }
 795  
 796      try {
 797          $localcfg = get_config('core');
 798      } catch (dml_exception $e) {
 799          // Most probably empty db, going to install soon.
 800          return;
 801      }
 802  
 803      foreach ($localcfg as $name => $value) {
 804          // Note that get_config() keeps forced settings
 805          // and normalises values to string if possible.
 806          $CFG->{$name} = $value;
 807      }
 808  }
 809  
 810  /**
 811   * Initialises $FULLME and friends. Private function. Should only be called from
 812   * setup.php.
 813   */
 814  function initialise_fullme() {
 815      global $CFG, $FULLME, $ME, $SCRIPT, $FULLSCRIPT;
 816  
 817      // Detect common config error.
 818      if (substr($CFG->wwwroot, -1) == '/') {
 819          print_error('wwwrootslash', 'error');
 820      }
 821  
 822      if (CLI_SCRIPT) {
 823          initialise_fullme_cli();
 824          return;
 825      }
 826      if (!empty($CFG->overridetossl)) {
 827          if (strpos($CFG->wwwroot, 'http://') === 0) {
 828              $CFG->wwwroot = str_replace('http:', 'https:', $CFG->wwwroot);
 829          } else {
 830              unset_config('overridetossl');
 831          }
 832      }
 833  
 834      $rurl = setup_get_remote_url();
 835      $wwwroot = parse_url($CFG->wwwroot.'/');
 836  
 837      if (empty($rurl['host'])) {
 838          // missing host in request header, probably not a real browser, let's ignore them
 839  
 840      } else if (!empty($CFG->reverseproxy)) {
 841          // $CFG->reverseproxy specifies if reverse proxy server used
 842          // Used in load balancing scenarios.
 843          // Do not abuse this to try to solve lan/wan access problems!!!!!
 844  
 845      } else {
 846          if (($rurl['host'] !== $wwwroot['host']) or
 847                  (!empty($wwwroot['port']) and $rurl['port'] != $wwwroot['port']) or
 848                  (strpos($rurl['path'], $wwwroot['path']) !== 0)) {
 849  
 850              // Explain the problem and redirect them to the right URL
 851              if (!defined('NO_MOODLE_COOKIES')) {
 852                  define('NO_MOODLE_COOKIES', true);
 853              }
 854              // The login/token.php script should call the correct url/port.
 855              if (defined('REQUIRE_CORRECT_ACCESS') && REQUIRE_CORRECT_ACCESS) {
 856                  $wwwrootport = empty($wwwroot['port'])?'':$wwwroot['port'];
 857                  $calledurl = $rurl['host'];
 858                  if (!empty($rurl['port'])) {
 859                      $calledurl .=  ':'. $rurl['port'];
 860                  }
 861                  $correcturl = $wwwroot['host'];
 862                  if (!empty($wwwrootport)) {
 863                      $correcturl .=  ':'. $wwwrootport;
 864                  }
 865                  throw new moodle_exception('requirecorrectaccess', 'error', '', null,
 866                      'You called ' . $calledurl .', you should have called ' . $correcturl);
 867              }
 868              redirect($CFG->wwwroot, get_string('wwwrootmismatch', 'error', $CFG->wwwroot), 3);
 869          }
 870      }
 871  
 872      // Check that URL is under $CFG->wwwroot.
 873      if (strpos($rurl['path'], $wwwroot['path']) === 0) {
 874          $SCRIPT = substr($rurl['path'], strlen($wwwroot['path'])-1);
 875      } else {
 876          // Probably some weird external script
 877          $SCRIPT = $FULLSCRIPT = $FULLME = $ME = null;
 878          return;
 879      }
 880  
 881      // $CFG->sslproxy specifies if external SSL appliance is used
 882      // (That is, the Moodle server uses http, with an external box translating everything to https).
 883      if (empty($CFG->sslproxy)) {
 884          if ($rurl['scheme'] === 'http' and $wwwroot['scheme'] === 'https') {
 885              if (defined('REQUIRE_CORRECT_ACCESS') && REQUIRE_CORRECT_ACCESS) {
 886                  print_error('sslonlyaccess', 'error');
 887              } else {
 888                  redirect($CFG->wwwroot, get_string('wwwrootmismatch', 'error', $CFG->wwwroot), 3);
 889              }
 890          }
 891      } else {
 892          if ($wwwroot['scheme'] !== 'https') {
 893              throw new coding_exception('Must use https address in wwwroot when ssl proxy enabled!');
 894          }
 895          $rurl['scheme'] = 'https'; // make moodle believe it runs on https, squid or something else it doing it
 896          $_SERVER['HTTPS'] = 'on'; // Override $_SERVER to help external libraries with their HTTPS detection.
 897          $_SERVER['SERVER_PORT'] = 443; // Assume default ssl port for the proxy.
 898      }
 899  
 900      // Hopefully this will stop all those "clever" admins trying to set up moodle
 901      // with two different addresses in intranet and Internet.
 902      // Port forwarding is still allowed!
 903      if (!empty($CFG->reverseproxy) && $rurl['host'] === $wwwroot['host'] && (empty($wwwroot['port']) || $rurl['port'] === $wwwroot['port'])) {
 904          print_error('reverseproxyabused', 'error');
 905      }
 906  
 907      $hostandport = $rurl['scheme'] . '://' . $wwwroot['host'];
 908      if (!empty($wwwroot['port'])) {
 909          $hostandport .= ':'.$wwwroot['port'];
 910      }
 911  
 912      $FULLSCRIPT = $hostandport . $rurl['path'];
 913      $FULLME = $hostandport . $rurl['fullpath'];
 914      $ME = $rurl['fullpath'];
 915  }
 916  
 917  /**
 918   * Initialises $FULLME and friends for command line scripts.
 919   * This is a private method for use by initialise_fullme.
 920   */
 921  function initialise_fullme_cli() {
 922      global $CFG, $FULLME, $ME, $SCRIPT, $FULLSCRIPT;
 923  
 924      // Urls do not make much sense in CLI scripts
 925      $backtrace = debug_backtrace();
 926      $topfile = array_pop($backtrace);
 927      $topfile = realpath($topfile['file']);
 928      $dirroot = realpath($CFG->dirroot);
 929  
 930      if (strpos($topfile, $dirroot) !== 0) {
 931          // Probably some weird external script
 932          $SCRIPT = $FULLSCRIPT = $FULLME = $ME = null;
 933      } else {
 934          $relativefile = substr($topfile, strlen($dirroot));
 935          $relativefile = str_replace('\\', '/', $relativefile); // Win fix
 936          $SCRIPT = $FULLSCRIPT = $relativefile;
 937          $FULLME = $ME = null;
 938      }
 939  }
 940  
 941  /**
 942   * Get the URL that PHP/the web server thinks it is serving. Private function
 943   * used by initialise_fullme. In your code, use $PAGE->url, $SCRIPT, etc.
 944   * @return array in the same format that parse_url returns, with the addition of
 945   *      a 'fullpath' element, which includes any slasharguments path.
 946   */
 947  function setup_get_remote_url() {
 948      $rurl = array();
 949      if (isset($_SERVER['HTTP_HOST'])) {
 950          list($rurl['host']) = explode(':', $_SERVER['HTTP_HOST']);
 951      } else {
 952          $rurl['host'] = null;
 953      }
 954      $rurl['port'] = (int)$_SERVER['SERVER_PORT'];
 955      $rurl['path'] = $_SERVER['SCRIPT_NAME']; // Script path without slash arguments
 956      $rurl['scheme'] = (empty($_SERVER['HTTPS']) or $_SERVER['HTTPS'] === 'off' or $_SERVER['HTTPS'] === 'Off' or $_SERVER['HTTPS'] === 'OFF') ? 'http' : 'https';
 957  
 958      if (stripos($_SERVER['SERVER_SOFTWARE'], 'apache') !== false) {
 959          //Apache server
 960          $rurl['fullpath'] = $_SERVER['REQUEST_URI'];
 961  
 962          // Fixing a known issue with:
 963          // - Apache versions lesser than 2.4.11
 964          // - PHP deployed in Apache as PHP-FPM via mod_proxy_fcgi
 965          // - PHP versions lesser than 5.6.3 and 5.5.18.
 966          if (isset($_SERVER['PATH_INFO']) && (php_sapi_name() === 'fpm-fcgi') && isset($_SERVER['SCRIPT_NAME'])) {
 967              $pathinfodec = rawurldecode($_SERVER['PATH_INFO']);
 968              $lenneedle = strlen($pathinfodec);
 969              // Checks whether SCRIPT_NAME ends with PATH_INFO, URL-decoded.
 970              if (substr($_SERVER['SCRIPT_NAME'], -$lenneedle) === $pathinfodec) {
 971                  // This is the "Apache 2.4.10- running PHP-FPM via mod_proxy_fcgi" fingerprint,
 972                  // at least on CentOS 7 (Apache/2.4.6 PHP/5.4.16) and Ubuntu 14.04 (Apache/2.4.7 PHP/5.5.9)
 973                  // => SCRIPT_NAME contains 'slash arguments' data too, which is wrongly exposed via PATH_INFO as URL-encoded.
 974                  // Fix both $_SERVER['PATH_INFO'] and $_SERVER['SCRIPT_NAME'].
 975                  $lenhaystack = strlen($_SERVER['SCRIPT_NAME']);
 976                  $pos = $lenhaystack - $lenneedle;
 977                  // Here $pos is greater than 0 but let's double check it.
 978                  if ($pos > 0) {
 979                      $_SERVER['PATH_INFO'] = $pathinfodec;
 980                      $_SERVER['SCRIPT_NAME'] = substr($_SERVER['SCRIPT_NAME'], 0, $pos);
 981                  }
 982              }
 983          }
 984  
 985      } else if (stripos($_SERVER['SERVER_SOFTWARE'], 'iis') !== false) {
 986          //IIS - needs a lot of tweaking to make it work
 987          $rurl['fullpath'] = $_SERVER['SCRIPT_NAME'];
 988  
 989          // NOTE: we should ignore PATH_INFO because it is incorrectly encoded using 8bit filesystem legacy encoding in IIS.
 990          //       Since 2.0, we rely on IIS rewrite extensions like Helicon ISAPI_rewrite
 991          //         example rule: RewriteRule ^([^\?]+?\.php)(\/.+)$ $1\?file=$2 [QSA]
 992          //       OR
 993          //       we rely on a proper IIS 6.0+ configuration: the 'FastCGIUtf8ServerVariables' registry key.
 994          if (isset($_SERVER['PATH_INFO']) and $_SERVER['PATH_INFO'] !== '') {
 995              // Check that PATH_INFO works == must not contain the script name.
 996              if (strpos($_SERVER['PATH_INFO'], $_SERVER['SCRIPT_NAME']) === false) {
 997                  $rurl['fullpath'] .= clean_param(urldecode($_SERVER['PATH_INFO']), PARAM_PATH);
 998              }
 999          }
1000  
1001          if (isset($_SERVER['QUERY_STRING']) and $_SERVER['QUERY_STRING'] !== '') {
1002              $rurl['fullpath'] .= '?'.$_SERVER['QUERY_STRING'];
1003          }
1004          $_SERVER['REQUEST_URI'] = $rurl['fullpath']; // extra IIS compatibility
1005  
1006  /* NOTE: following servers are not fully tested! */
1007  
1008      } else if (stripos($_SERVER['SERVER_SOFTWARE'], 'lighttpd') !== false) {
1009          //lighttpd - not officially supported
1010          $rurl['fullpath'] = $_SERVER['REQUEST_URI']; // TODO: verify this is always properly encoded
1011  
1012      } else if (stripos($_SERVER['SERVER_SOFTWARE'], 'nginx') !== false) {
1013          //nginx - not officially supported
1014          if (!isset($_SERVER['SCRIPT_NAME'])) {
1015              die('Invalid server configuration detected, please try to add "fastcgi_param SCRIPT_NAME $fastcgi_script_name;" to the nginx server configuration.');
1016          }
1017          $rurl['fullpath'] = $_SERVER['REQUEST_URI']; // TODO: verify this is always properly encoded
1018  
1019       } else if (stripos($_SERVER['SERVER_SOFTWARE'], 'cherokee') !== false) {
1020           //cherokee - not officially supported
1021           $rurl['fullpath'] = $_SERVER['REQUEST_URI']; // TODO: verify this is always properly encoded
1022  
1023       } else if (stripos($_SERVER['SERVER_SOFTWARE'], 'zeus') !== false) {
1024           //zeus - not officially supported
1025           $rurl['fullpath'] = $_SERVER['REQUEST_URI']; // TODO: verify this is always properly encoded
1026  
1027      } else if (stripos($_SERVER['SERVER_SOFTWARE'], 'LiteSpeed') !== false) {
1028          //LiteSpeed - not officially supported
1029          $rurl['fullpath'] = $_SERVER['REQUEST_URI']; // TODO: verify this is always properly encoded
1030  
1031      } else if ($_SERVER['SERVER_SOFTWARE'] === 'HTTPD') {
1032          //obscure name found on some servers - this is definitely not supported
1033          $rurl['fullpath'] = $_SERVER['REQUEST_URI']; // TODO: verify this is always properly encoded
1034  
1035      } else if (strpos($_SERVER['SERVER_SOFTWARE'], 'PHP') === 0) {
1036          // built-in PHP Development Server
1037          $rurl['fullpath'] = $_SERVER['REQUEST_URI'];
1038  
1039      } else {
1040          throw new moodle_exception('unsupportedwebserver', 'error', '', $_SERVER['SERVER_SOFTWARE']);
1041      }
1042  
1043      // sanitize the url a bit more, the encoding style may be different in vars above
1044      $rurl['fullpath'] = str_replace('"', '%22', $rurl['fullpath']);
1045      $rurl['fullpath'] = str_replace('\'', '%27', $rurl['fullpath']);
1046  
1047      return $rurl;
1048  }
1049  
1050  /**
1051   * Try to work around the 'max_input_vars' restriction if necessary.
1052   */
1053  function workaround_max_input_vars() {
1054      // Make sure this gets executed only once from lib/setup.php!
1055      static $executed = false;
1056      if ($executed) {
1057          debugging('workaround_max_input_vars() must be called only once!');
1058          return;
1059      }
1060      $executed = true;
1061  
1062      if (!isset($_SERVER["CONTENT_TYPE"]) or strpos($_SERVER["CONTENT_TYPE"], 'multipart/form-data') !== false) {
1063          // Not a post or 'multipart/form-data' which is not compatible with "php://input" reading.
1064          return;
1065      }
1066  
1067      if (!isloggedin() or isguestuser()) {
1068          // Only real users post huge forms.
1069          return;
1070      }
1071  
1072      $max = (int)ini_get('max_input_vars');
1073  
1074      if ($max <= 0) {
1075          // Most probably PHP < 5.3.9 that does not implement this limit.
1076          return;
1077      }
1078  
1079      if ($max >= 200000) {
1080          // This value should be ok for all our forms, by setting it in php.ini
1081          // admins may prevent any unexpected regressions caused by this hack.
1082  
1083          // Note there is no need to worry about DDoS caused by making this limit very high
1084          // because there are very many easier ways to DDoS any Moodle server.
1085          return;
1086      }
1087  
1088      // Worst case is advanced checkboxes which use up to two max_input_vars
1089      // slots for each entry in $_POST, because of sending two fields with the
1090      // same name. So count everything twice just in case.
1091      if (count($_POST, COUNT_RECURSIVE) * 2 < $max) {
1092          return;
1093      }
1094  
1095      // Large POST request with enctype supported by php://input.
1096      // Parse php://input in chunks to bypass max_input_vars limit, which also applies to parse_str().
1097      $str = file_get_contents("php://input");
1098      if ($str === false or $str === '') {
1099          // Some weird error.
1100          return;
1101      }
1102  
1103      $delim = '&';
1104      $fun = function($p) use ($delim) {
1105          return implode($delim, $p);
1106      };
1107      $chunks = array_map($fun, array_chunk(explode($delim, $str), $max));
1108  
1109      // Clear everything from existing $_POST array, otherwise it might be included
1110      // twice (this affects array params primarily).
1111      foreach ($_POST as $key => $value) {
1112          unset($_POST[$key]);
1113          // Also clear from request array - but only the things that are in $_POST,
1114          // that way it will leave the things from a get request if any.
1115          unset($_REQUEST[$key]);
1116      }
1117  
1118      foreach ($chunks as $chunk) {
1119          $values = array();
1120          parse_str($chunk, $values);
1121  
1122          merge_query_params($_POST, $values);
1123          merge_query_params($_REQUEST, $values);
1124      }
1125  }
1126  
1127  /**
1128   * Merge parsed POST chunks.
1129   *
1130   * NOTE: this is not perfect, but it should work in most cases hopefully.
1131   *
1132   * @param array $target
1133   * @param array $values
1134   */
1135  function merge_query_params(array &$target, array $values) {
1136      if (isset($values[0]) and isset($target[0])) {
1137          // This looks like a split [] array, lets verify the keys are continuous starting with 0.
1138          $keys1 = array_keys($values);
1139          $keys2 = array_keys($target);
1140          if ($keys1 === array_keys($keys1) and $keys2 === array_keys($keys2)) {
1141              foreach ($values as $v) {
1142                  $target[] = $v;
1143              }
1144              return;
1145          }
1146      }
1147      foreach ($values as $k => $v) {
1148          if (!isset($target[$k])) {
1149              $target[$k] = $v;
1150              continue;
1151          }
1152          if (is_array($target[$k]) and is_array($v)) {
1153              merge_query_params($target[$k], $v);
1154              continue;
1155          }
1156          // We should not get here unless there are duplicates in params.
1157          $target[$k] = $v;
1158      }
1159  }
1160  
1161  /**
1162   * Initializes our performance info early.
1163   *
1164   * Pairs up with get_performance_info() which is actually
1165   * in moodlelib.php. This function is here so that we can
1166   * call it before all the libs are pulled in.
1167   *
1168   * @uses $PERF
1169   */
1170  function init_performance_info() {
1171  
1172      global $PERF, $CFG, $USER;
1173  
1174      $PERF = new stdClass();
1175      $PERF->logwrites = 0;
1176      if (function_exists('microtime')) {
1177          $PERF->starttime = microtime();
1178      }
1179      if (function_exists('memory_get_usage')) {
1180          $PERF->startmemory = memory_get_usage();
1181      }
1182      if (function_exists('posix_times')) {
1183          $PERF->startposixtimes = posix_times();
1184      }
1185  }
1186  
1187  /**
1188   * Indicates whether we are in the middle of the initial Moodle install.
1189   *
1190   * Very occasionally it is necessary avoid running certain bits of code before the
1191   * Moodle installation has completed. The installed flag is set in admin/index.php
1192   * after Moodle core and all the plugins have been installed, but just before
1193   * the person doing the initial install is asked to choose the admin password.
1194   *
1195   * @return boolean true if the initial install is not complete.
1196   */
1197  function during_initial_install() {
1198      global $CFG;
1199      return empty($CFG->rolesactive);
1200  }
1201  
1202  /**
1203   * Function to raise the memory limit to a new value.
1204   * Will respect the memory limit if it is higher, thus allowing
1205   * settings in php.ini, apache conf or command line switches
1206   * to override it.
1207   *
1208   * The memory limit should be expressed with a constant
1209   * MEMORY_STANDARD, MEMORY_EXTRA or MEMORY_HUGE.
1210   * It is possible to use strings or integers too (eg:'128M').
1211   *
1212   * @param mixed $newlimit the new memory limit
1213   * @return bool success
1214   */
1215  function raise_memory_limit($newlimit) {
1216      global $CFG;
1217  
1218      if ($newlimit == MEMORY_UNLIMITED) {
1219          ini_set('memory_limit', -1);
1220          return true;
1221  
1222      } else if ($newlimit == MEMORY_STANDARD) {
1223          if (PHP_INT_SIZE > 4) {
1224              $newlimit = get_real_size('128M'); // 64bit needs more memory
1225          } else {
1226              $newlimit = get_real_size('96M');
1227          }
1228  
1229      } else if ($newlimit == MEMORY_EXTRA) {
1230          if (PHP_INT_SIZE > 4) {
1231              $newlimit = get_real_size('384M'); // 64bit needs more memory
1232          } else {
1233              $newlimit = get_real_size('256M');
1234          }
1235          if (!empty($CFG->extramemorylimit)) {
1236              $extra = get_real_size($CFG->extramemorylimit);
1237              if ($extra > $newlimit) {
1238                  $newlimit = $extra;
1239              }
1240          }
1241  
1242      } else if ($newlimit == MEMORY_HUGE) {
1243          // MEMORY_HUGE uses 2G or MEMORY_EXTRA, whichever is bigger.
1244          $newlimit = get_real_size('2G');
1245          if (!empty($CFG->extramemorylimit)) {
1246              $extra = get_real_size($CFG->extramemorylimit);
1247              if ($extra > $newlimit) {
1248                  $newlimit = $extra;
1249              }
1250          }
1251  
1252      } else {
1253          $newlimit = get_real_size($newlimit);
1254      }
1255  
1256      if ($newlimit <= 0) {
1257          debugging('Invalid memory limit specified.');
1258          return false;
1259      }
1260  
1261      $cur = ini_get('memory_limit');
1262      if (empty($cur)) {
1263          // if php is compiled without --enable-memory-limits
1264          // apparently memory_limit is set to ''
1265          $cur = 0;
1266      } else {
1267          if ($cur == -1){
1268              return true; // unlimited mem!
1269          }
1270          $cur = get_real_size($cur);
1271      }
1272  
1273      if ($newlimit > $cur) {
1274          ini_set('memory_limit', $newlimit);
1275          return true;
1276      }
1277      return false;
1278  }
1279  
1280  /**
1281   * Function to reduce the memory limit to a new value.
1282   * Will respect the memory limit if it is lower, thus allowing
1283   * settings in php.ini, apache conf or command line switches
1284   * to override it
1285   *
1286   * The memory limit should be expressed with a string (eg:'64M')
1287   *
1288   * @param string $newlimit the new memory limit
1289   * @return bool
1290   */
1291  function reduce_memory_limit($newlimit) {
1292      if (empty($newlimit)) {
1293          return false;
1294      }
1295      $cur = ini_get('memory_limit');
1296      if (empty($cur)) {
1297          // if php is compiled without --enable-memory-limits
1298          // apparently memory_limit is set to ''
1299          $cur = 0;
1300      } else {
1301          if ($cur == -1){
1302              return true; // unlimited mem!
1303          }
1304          $cur = get_real_size($cur);
1305      }
1306  
1307      $new = get_real_size($newlimit);
1308      // -1 is smaller, but it means unlimited
1309      if ($new < $cur && $new != -1) {
1310          ini_set('memory_limit', $newlimit);
1311          return true;
1312      }
1313      return false;
1314  }
1315  
1316  /**
1317   * Converts numbers like 10M into bytes.
1318   *
1319   * @param string $size The size to be converted
1320   * @return int
1321   */
1322  function get_real_size($size = 0) {
1323      if (!$size) {
1324          return 0;
1325      }
1326  
1327      static $binaryprefixes = array(
1328          'K' => 1024 ** 1,
1329          'k' => 1024 ** 1,
1330          'M' => 1024 ** 2,
1331          'm' => 1024 ** 2,
1332          'G' => 1024 ** 3,
1333          'g' => 1024 ** 3,
1334          'T' => 1024 ** 4,
1335          't' => 1024 ** 4,
1336          'P' => 1024 ** 5,
1337          'p' => 1024 ** 5,
1338      );
1339  
1340      if (preg_match('/^([0-9]+)([KMGTP])/i', $size, $matches)) {
1341          return $matches[1] * $binaryprefixes[$matches[2]];
1342      }
1343  
1344      return (int) $size;
1345  }
1346  
1347  /**
1348   * Try to disable all output buffering and purge
1349   * all headers.
1350   *
1351   * @access private to be called only from lib/setup.php !
1352   * @return void
1353   */
1354  function disable_output_buffering() {
1355      $olddebug = error_reporting(0);
1356  
1357      // disable compression, it would prevent closing of buffers
1358      if (ini_get_bool('zlib.output_compression')) {
1359          ini_set('zlib.output_compression', 'Off');
1360      }
1361  
1362      // try to flush everything all the time
1363      ob_implicit_flush(true);
1364  
1365      // close all buffers if possible and discard any existing output
1366      // this can actually work around some whitespace problems in config.php
1367      while(ob_get_level()) {
1368          if (!ob_end_clean()) {
1369              // prevent infinite loop when buffer can not be closed
1370              break;
1371          }
1372      }
1373  
1374      // disable any other output handlers
1375      ini_set('output_handler', '');
1376  
1377      error_reporting($olddebug);
1378  
1379      // Disable buffering in nginx.
1380      header('X-Accel-Buffering: no');
1381  
1382  }
1383  
1384  /**
1385   * Check whether a major upgrade is needed.
1386   *
1387   * That is defined as an upgrade that changes something really fundamental
1388   * in the database, so nothing can possibly work until the database has
1389   * been updated, and that is defined by the hard-coded version number in
1390   * this function.
1391   *
1392   * @return bool
1393   */
1394  function is_major_upgrade_required() {
1395      global $CFG;
1396      $lastmajordbchanges = 2019050100.01;
1397  
1398      $required = empty($CFG->version);
1399      $required = $required || (float)$CFG->version < $lastmajordbchanges;
1400      $required = $required || during_initial_install();
1401      $required = $required || !empty($CFG->adminsetuppending);
1402  
1403      return $required;
1404  }
1405  
1406  /**
1407   * Redirect to the Notifications page if a major upgrade is required, and
1408   * terminate the current user session.
1409   */
1410  function redirect_if_major_upgrade_required() {
1411      global $CFG;
1412      if (is_major_upgrade_required()) {
1413          try {
1414              @\core\session\manager::terminate_current();
1415          } catch (Exception $e) {
1416              // Ignore any errors, redirect to upgrade anyway.
1417          }
1418          $url = $CFG->wwwroot . '/' . $CFG->admin . '/index.php';
1419          @header($_SERVER['SERVER_PROTOCOL'] . ' 303 See Other');
1420          @header('Location: ' . $url);
1421          echo bootstrap_renderer::plain_redirect_message(htmlspecialchars($url));
1422          exit;
1423      }
1424  }
1425  
1426  /**
1427   * Makes sure that upgrade process is not running
1428   *
1429   * To be inserted in the core functions that can not be called by pluigns during upgrade.
1430   * Core upgrade should not use any API functions at all.
1431   * See {@link http://docs.moodle.org/dev/Upgrade_API#Upgrade_code_restrictions}
1432   *
1433   * @throws moodle_exception if executed from inside of upgrade script and $warningonly is false
1434   * @param bool $warningonly if true displays a warning instead of throwing an exception
1435   * @return bool true if executed from outside of upgrade process, false if from inside upgrade process and function is used for warning only
1436   */
1437  function upgrade_ensure_not_running($warningonly = false) {
1438      global $CFG;
1439      if (!empty($CFG->upgraderunning)) {
1440          if (!$warningonly) {
1441              throw new moodle_exception('cannotexecduringupgrade');
1442          } else {
1443              debugging(get_string('cannotexecduringupgrade', 'error'), DEBUG_DEVELOPER);
1444              return false;
1445          }
1446      }
1447      return true;
1448  }
1449  
1450  /**
1451   * Function to check if a directory exists and by default create it if not exists.
1452   *
1453   * Previously this was accepting paths only from dataroot, but we now allow
1454   * files outside of dataroot if you supply custom paths for some settings in config.php.
1455   * This function does not verify that the directory is writable.
1456   *
1457   * NOTE: this function uses current file stat cache,
1458   *       please use clearstatcache() before this if you expect that the
1459   *       directories may have been removed recently from a different request.
1460   *
1461   * @param string $dir absolute directory path
1462   * @param boolean $create directory if does not exist
1463   * @param boolean $recursive create directory recursively
1464   * @return boolean true if directory exists or created, false otherwise
1465   */
1466  function check_dir_exists($dir, $create = true, $recursive = true) {
1467      global $CFG;
1468  
1469      umask($CFG->umaskpermissions);
1470  
1471      if (is_dir($dir)) {
1472          return true;
1473      }
1474  
1475      if (!$create) {
1476          return false;
1477      }
1478  
1479      return mkdir($dir, $CFG->directorypermissions, $recursive);
1480  }
1481  
1482  /**
1483   * Create a new unique directory within the specified directory.
1484   *
1485   * @param string $basedir The directory to create your new unique directory within.
1486   * @param bool $exceptiononerror throw exception if error encountered
1487   * @return string The created directory
1488   * @throws invalid_dataroot_permissions
1489   */
1490  function make_unique_writable_directory($basedir, $exceptiononerror = true) {
1491      if (!is_dir($basedir) || !is_writable($basedir)) {
1492          // The basedir is not writable. We will not be able to create the child directory.
1493          if ($exceptiononerror) {
1494              throw new invalid_dataroot_permissions($basedir . ' is not writable. Unable to create a unique directory within it.');
1495          } else {
1496              return false;
1497          }
1498      }
1499  
1500      do {
1501          // Let's use uniqid() because it's "unique enough" (microtime based). The loop does handle repetitions.
1502          // Windows and old PHP don't like very long paths, so try to keep this shorter. See MDL-69975.
1503          $uniquedir = $basedir . DIRECTORY_SEPARATOR . uniqid();
1504      } while (
1505              // Ensure that basedir is still writable - if we do not check, we could get stuck in a loop here.
1506              is_writable($basedir) &&
1507  
1508              // Make the new unique directory. If the directory already exists, it will return false.
1509              !make_writable_directory($uniquedir, $exceptiononerror) &&
1510  
1511              // Ensure that the directory now exists
1512              file_exists($uniquedir) && is_dir($uniquedir)
1513          );
1514  
1515      // Check that the directory was correctly created.
1516      if (!file_exists($uniquedir) || !is_dir($uniquedir) || !is_writable($uniquedir)) {
1517          if ($exceptiononerror) {
1518              throw new invalid_dataroot_permissions('Unique directory creation failed.');
1519          } else {
1520              return false;
1521          }
1522      }
1523  
1524      return $uniquedir;
1525  }
1526  
1527  /**
1528   * Create a directory and make sure it is writable.
1529   *
1530   * @private
1531   * @param string $dir  the full path of the directory to be created
1532   * @param bool $exceptiononerror throw exception if error encountered
1533   * @return string|false Returns full path to directory if successful, false if not; may throw exception
1534   */
1535  function make_writable_directory($dir, $exceptiononerror = true) {
1536      global $CFG;
1537  
1538      if (file_exists($dir) and !is_dir($dir)) {
1539          if ($exceptiononerror) {
1540              throw new coding_exception($dir.' directory can not be created, file with the same name already exists.');
1541          } else {
1542              return false;
1543          }
1544      }
1545  
1546      umask($CFG->umaskpermissions);
1547  
1548      if (!file_exists($dir)) {
1549          if (!@mkdir($dir, $CFG->directorypermissions, true)) {
1550              clearstatcache();
1551              // There might be a race condition when creating directory.
1552              if (!is_dir($dir)) {
1553                  if ($exceptiononerror) {
1554                      throw new invalid_dataroot_permissions($dir.' can not be created, check permissions.');
1555                  } else {
1556                      debugging('Can not create directory: '.$dir, DEBUG_DEVELOPER);
1557                      return false;
1558                  }
1559              }
1560          }
1561      }
1562  
1563      if (!is_writable($dir)) {
1564          if ($exceptiononerror) {
1565              throw new invalid_dataroot_permissions($dir.' is not writable, check permissions.');
1566          } else {
1567              return false;
1568          }
1569      }
1570  
1571      return $dir;
1572  }
1573  
1574  /**
1575   * Protect a directory from web access.
1576   * Could be extended in the future to support other mechanisms (e.g. other webservers).
1577   *
1578   * @private
1579   * @param string $dir  the full path of the directory to be protected
1580   */
1581  function protect_directory($dir) {
1582      global $CFG;
1583      // Make sure a .htaccess file is here, JUST IN CASE the files area is in the open and .htaccess is supported
1584      if (!file_exists("$dir/.htaccess")) {
1585          if ($handle = fopen("$dir/.htaccess", 'w')) {   // For safety
1586              @fwrite($handle, "deny from all\r\nAllowOverride None\r\nNote: this file is broken intentionally, we do not want anybody to undo it in subdirectory!\r\n");
1587              @fclose($handle);
1588              @chmod("$dir/.htaccess", $CFG->filepermissions);
1589          }
1590      }
1591  }
1592  
1593  /**
1594   * Create a directory under dataroot and make sure it is writable.
1595   * Do not use for temporary and cache files - see make_temp_directory() and make_cache_directory().
1596   *
1597   * @param string $directory  the full path of the directory to be created under $CFG->dataroot
1598   * @param bool $exceptiononerror throw exception if error encountered
1599   * @return string|false Returns full path to directory if successful, false if not; may throw exception
1600   */
1601  function make_upload_directory($directory, $exceptiononerror = true) {
1602      global $CFG;
1603  
1604      if (strpos($directory, 'temp/') === 0 or $directory === 'temp') {
1605          debugging('Use make_temp_directory() for creation of temporary directory and $CFG->tempdir to get the location.');
1606  
1607      } else if (strpos($directory, 'cache/') === 0 or $directory === 'cache') {
1608          debugging('Use make_cache_directory() for creation of cache directory and $CFG->cachedir to get the location.');
1609  
1610      } else if (strpos($directory, 'localcache/') === 0 or $directory === 'localcache') {
1611          debugging('Use make_localcache_directory() for creation of local cache directory and $CFG->localcachedir to get the location.');
1612      }
1613  
1614      protect_directory($CFG->dataroot);
1615      return make_writable_directory("$CFG->dataroot/$directory", $exceptiononerror);
1616  }
1617  
1618  /**
1619   * Get a per-request storage directory in the tempdir.
1620   *
1621   * The directory is automatically cleaned up during the shutdown handler.
1622   *
1623   * @param   bool    $exceptiononerror throw exception if error encountered
1624   * @param   bool    $forcecreate Force creation of a new parent directory
1625   * @return  string  Returns full path to directory if successful, false if not; may throw exception
1626   */
1627  function get_request_storage_directory($exceptiononerror = true, bool $forcecreate = false) {
1628      global $CFG;
1629  
1630      static $requestdir = null;
1631  
1632      $writabledirectoryexists = (null !== $requestdir);
1633      $writabledirectoryexists = $writabledirectoryexists && file_exists($requestdir);
1634      $writabledirectoryexists = $writabledirectoryexists && is_dir($requestdir);
1635      $writabledirectoryexists = $writabledirectoryexists && is_writable($requestdir);
1636      $createnewdirectory = $forcecreate || !$writabledirectoryexists;
1637  
1638      if ($createnewdirectory) {
1639  
1640          // Let's add the first chars of siteidentifier only. This is to help separate
1641          // paths on systems which host multiple moodles. We don't use the full id
1642          // as Windows and old PHP don't like very long paths. See MDL-69975.
1643          $basedir = $CFG->localrequestdir . '/' . substr($CFG->siteidentifier, 0, 4);
1644  
1645          make_writable_directory($basedir);
1646          protect_directory($basedir);
1647  
1648          if ($dir = make_unique_writable_directory($basedir, $exceptiononerror)) {
1649              // Register a shutdown handler to remove the directory.
1650              \core_shutdown_manager::register_function('remove_dir', [$dir]);
1651          }
1652  
1653          $requestdir = $dir;
1654      }
1655  
1656      return $requestdir;
1657  }
1658  
1659  /**
1660   * Create a per-request directory and make sure it is writable.
1661   * This can only be used during the current request and will be tidied away
1662   * automatically afterwards.
1663   *
1664   * A new, unique directory is always created within a shared base request directory.
1665   *
1666   * In some exceptional cases an alternative base directory may be required. This can be accomplished using the
1667   * $forcecreate parameter. Typically this will only be requried where the file may be required during a shutdown handler
1668   * which may or may not be registered after a previous request directory has been created.
1669   *
1670   * @param   bool    $exceptiononerror throw exception if error encountered
1671   * @param   bool    $forcecreate Force creation of a new parent directory
1672   * @return  string  The full path to directory if successful, false if not; may throw exception
1673   */
1674  function make_request_directory($exceptiononerror = true, bool $forcecreate = false) {
1675      $basedir = get_request_storage_directory($exceptiononerror, $forcecreate);
1676      return make_unique_writable_directory($basedir, $exceptiononerror);
1677  }
1678  
1679  /**
1680   * Get the full path of a directory under $CFG->backuptempdir.
1681   *
1682   * @param string $directory  the relative path of the directory under $CFG->backuptempdir
1683   * @return string|false Returns full path to directory given a valid string; otherwise, false.
1684   */
1685  function get_backup_temp_directory($directory) {
1686      global $CFG;
1687      if (($directory === null) || ($directory === false)) {
1688          return false;
1689      }
1690      return "$CFG->backuptempdir/$directory";
1691  }
1692  
1693  /**
1694   * Create a directory under $CFG->backuptempdir and make sure it is writable.
1695   *
1696   * Do not use for storing generic temp files - see make_temp_directory() instead for this purpose.
1697   *
1698   * Backup temporary files must be on a shared storage.
1699   *
1700   * @param string $directory  the relative path of the directory to be created under $CFG->backuptempdir
1701   * @param bool $exceptiononerror throw exception if error encountered
1702   * @return string|false Returns full path to directory if successful, false if not; may throw exception
1703   */
1704  function make_backup_temp_directory($directory, $exceptiononerror = true) {
1705      global $CFG;
1706      if ($CFG->backuptempdir !== "$CFG->tempdir/backup") {
1707          check_dir_exists($CFG->backuptempdir, true, true);
1708          protect_directory($CFG->backuptempdir);
1709      } else {
1710          protect_directory($CFG->tempdir);
1711      }
1712      return make_writable_directory("$CFG->backuptempdir/$directory", $exceptiononerror);
1713  }
1714  
1715  /**
1716   * Create a directory under tempdir and make sure it is writable.
1717   *
1718   * Where possible, please use make_request_directory() and limit the scope
1719   * of your data to the current HTTP request.
1720   *
1721   * Do not use for storing cache files - see make_cache_directory(), and
1722   * make_localcache_directory() instead for this purpose.
1723   *
1724   * Temporary files must be on a shared storage, and heavy usage is
1725   * discouraged due to the performance impact upon clustered environments.
1726   *
1727   * @param string $directory  the full path of the directory to be created under $CFG->tempdir
1728   * @param bool $exceptiononerror throw exception if error encountered
1729   * @return string|false Returns full path to directory if successful, false if not; may throw exception
1730   */
1731  function make_temp_directory($directory, $exceptiononerror = true) {
1732      global $CFG;
1733      if ($CFG->tempdir !== "$CFG->dataroot/temp") {
1734          check_dir_exists($CFG->tempdir, true, true);
1735          protect_directory($CFG->tempdir);
1736      } else {
1737          protect_directory($CFG->dataroot);
1738      }
1739      return make_writable_directory("$CFG->tempdir/$directory", $exceptiononerror);
1740  }
1741  
1742  /**
1743   * Create a directory under cachedir and make sure it is writable.
1744   *
1745   * Note: this cache directory is shared by all cluster nodes.
1746   *
1747   * @param string $directory  the full path of the directory to be created under $CFG->cachedir
1748   * @param bool $exceptiononerror throw exception if error encountered
1749   * @return string|false Returns full path to directory if successful, false if not; may throw exception
1750   */
1751  function make_cache_directory($directory, $exceptiononerror = true) {
1752      global $CFG;
1753      if ($CFG->cachedir !== "$CFG->dataroot/cache") {
1754          check_dir_exists($CFG->cachedir, true, true);
1755          protect_directory($CFG->cachedir);
1756      } else {
1757          protect_directory($CFG->dataroot);
1758      }
1759      return make_writable_directory("$CFG->cachedir/$directory", $exceptiononerror);
1760  }
1761  
1762  /**
1763   * Create a directory under localcachedir and make sure it is writable.
1764   * The files in this directory MUST NOT change, use revisions or content hashes to
1765   * work around this limitation - this means you can only add new files here.
1766   *
1767   * The content of this directory gets purged automatically on all cluster nodes
1768   * after calling purge_all_caches() before new data is written to this directory.
1769   *
1770   * Note: this local cache directory does not need to be shared by cluster nodes.
1771   *
1772   * @param string $directory the relative path of the directory to be created under $CFG->localcachedir
1773   * @param bool $exceptiononerror throw exception if error encountered
1774   * @return string|false Returns full path to directory if successful, false if not; may throw exception
1775   */
1776  function make_localcache_directory($directory, $exceptiononerror = true) {
1777      global $CFG;
1778  
1779      make_writable_directory($CFG->localcachedir, $exceptiononerror);
1780  
1781      if ($CFG->localcachedir !== "$CFG->dataroot/localcache") {
1782          protect_directory($CFG->localcachedir);
1783      } else {
1784          protect_directory($CFG->dataroot);
1785      }
1786  
1787      if (!isset($CFG->localcachedirpurged)) {
1788          $CFG->localcachedirpurged = 0;
1789      }
1790      $timestampfile = "$CFG->localcachedir/.lastpurged";
1791  
1792      if (!file_exists($timestampfile)) {
1793          touch($timestampfile);
1794          @chmod($timestampfile, $CFG->filepermissions);
1795  
1796      } else if (filemtime($timestampfile) <  $CFG->localcachedirpurged) {
1797          // This means our local cached dir was not purged yet.
1798          remove_dir($CFG->localcachedir, true);
1799          if ($CFG->localcachedir !== "$CFG->dataroot/localcache") {
1800              protect_directory($CFG->localcachedir);
1801          }
1802          touch($timestampfile);
1803          @chmod($timestampfile, $CFG->filepermissions);
1804          clearstatcache();
1805      }
1806  
1807      if ($directory === '') {
1808          return $CFG->localcachedir;
1809      }
1810  
1811      return make_writable_directory("$CFG->localcachedir/$directory", $exceptiononerror);
1812  }
1813  
1814  /**
1815   * Webserver access user logging
1816   */
1817  function set_access_log_user() {
1818      global $USER, $CFG;
1819      if ($USER && isset($USER->username)) {
1820          $logmethod = '';
1821          $logvalue = 0;
1822          if (!empty($CFG->apacheloguser) && function_exists('apache_note')) {
1823              $logmethod = 'apache';
1824              $logvalue = $CFG->apacheloguser;
1825          }
1826          if (!empty($CFG->headerloguser)) {
1827              $logmethod = 'header';
1828              $logvalue = $CFG->headerloguser;
1829          }
1830          if (!empty($logmethod)) {
1831              $loguserid = $USER->id;
1832              $logusername = clean_filename($USER->username);
1833              $logname = '';
1834              if (isset($USER->firstname)) {
1835                  // We can assume both will be set
1836                  // - even if to empty.
1837                  $logname = clean_filename($USER->firstname . " " . $USER->lastname);
1838              }
1839              if (\core\session\manager::is_loggedinas()) {
1840                  $realuser = \core\session\manager::get_realuser();
1841                  $logusername = clean_filename($realuser->username." as ".$logusername);
1842                  $logname = clean_filename($realuser->firstname." ".$realuser->lastname ." as ".$logname);
1843                  $loguserid = clean_filename($realuser->id." as ".$loguserid);
1844              }
1845              switch ($logvalue) {
1846                  case 3:
1847                      $logname = $logusername;
1848                      break;
1849                  case 2:
1850                      $logname = $logname;
1851                      break;
1852                  case 1:
1853                  default:
1854                      $logname = $loguserid;
1855                      break;
1856              }
1857              if ($logmethod == 'apache') {
1858                  apache_note('MOODLEUSER', $logname);
1859              }
1860  
1861              if ($logmethod == 'header') {
1862                  header("X-MOODLEUSER: $logname");
1863              }
1864          }
1865      }
1866  }
1867  
1868  /**
1869   * This class solves the problem of how to initialise $OUTPUT.
1870   *
1871   * The problem is caused be two factors
1872   * <ol>
1873   * <li>On the one hand, we cannot be sure when output will start. In particular,
1874   * an error, which needs to be displayed, could be thrown at any time.</li>
1875   * <li>On the other hand, we cannot be sure when we will have all the information
1876   * necessary to correctly initialise $OUTPUT. $OUTPUT depends on the theme, which
1877   * (potentially) depends on the current course, course categories, and logged in user.
1878   * It also depends on whether the current page requires HTTPS.</li>
1879   * </ol>
1880   *
1881   * So, it is hard to find a single natural place during Moodle script execution,
1882   * which we can guarantee is the right time to initialise $OUTPUT. Instead we
1883   * adopt the following strategy
1884   * <ol>
1885   * <li>We will initialise $OUTPUT the first time it is used.</li>
1886   * <li>If, after $OUTPUT has been initialised, the script tries to change something
1887   * that $OUTPUT depends on, we throw an exception making it clear that the script
1888   * did something wrong.
1889   * </ol>
1890   *
1891   * The only problem with that is, how do we initialise $OUTPUT on first use if,
1892   * it is going to be used like $OUTPUT->somthing(...)? Well that is where this
1893   * class comes in. Initially, we set up $OUTPUT = new bootstrap_renderer(). Then,
1894   * when any method is called on that object, we initialise $OUTPUT, and pass the call on.
1895   *
1896   * Note that this class is used before lib/outputlib.php has been loaded, so we
1897   * must be careful referring to classes/functions from there, they may not be
1898   * defined yet, and we must avoid fatal errors.
1899   *
1900   * @copyright 2009 Tim Hunt
1901   * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
1902   * @since     Moodle 2.0
1903   */
1904  class bootstrap_renderer {
1905      /**
1906       * Handles re-entrancy. Without this, errors or debugging output that occur
1907       * during the initialisation of $OUTPUT, cause infinite recursion.
1908       * @var boolean
1909       */
1910      protected $initialising = false;
1911  
1912      /**
1913       * Have we started output yet?
1914       * @return boolean true if the header has been printed.
1915       */
1916      public function has_started() {
1917          return false;
1918      }
1919  
1920      /**
1921       * Constructor - to be used by core code only.
1922       * @param string $method The method to call
1923       * @param array $arguments Arguments to pass to the method being called
1924       * @return string
1925       */
1926      public function __call($method, $arguments) {
1927          global $OUTPUT, $PAGE;
1928  
1929          $recursing = false;
1930          if ($method == 'notification') {
1931              // Catch infinite recursion caused by debugging output during print_header.
1932              $backtrace = debug_backtrace();
1933              array_shift($backtrace);
1934              array_shift($backtrace);
1935              $recursing = is_early_init($backtrace);
1936          }
1937  
1938          $earlymethods = array(
1939              'fatal_error' => 'early_error',
1940              'notification' => 'early_notification',
1941          );
1942  
1943          // If lib/outputlib.php has been loaded, call it.
1944          if (!empty($PAGE) && !$recursing) {
1945              if (array_key_exists($method, $earlymethods)) {
1946                  //prevent PAGE->context warnings - exceptions might appear before we set any context
1947                  $PAGE->set_context(null);
1948              }
1949              $PAGE->initialise_theme_and_output();
1950              return call_user_func_array(array($OUTPUT, $method), $arguments);
1951          }
1952  
1953          $this->initialising = true;
1954  
1955          // Too soon to initialise $OUTPUT, provide a couple of key methods.
1956          if (array_key_exists($method, $earlymethods)) {
1957              return call_user_func_array(array('bootstrap_renderer', $earlymethods[$method]), $arguments);
1958          }
1959  
1960          throw new coding_exception('Attempt to start output before enough information is known to initialise the theme.');
1961      }
1962  
1963      /**
1964       * Returns nicely formatted error message in a div box.
1965       * @static
1966       * @param string $message error message
1967       * @param string $moreinfourl (ignored in early errors)
1968       * @param string $link (ignored in early errors)
1969       * @param array $backtrace
1970       * @param string $debuginfo
1971       * @return string
1972       */
1973      public static function early_error_content($message, $moreinfourl, $link, $backtrace, $debuginfo = null) {
1974          global $CFG;
1975  
1976          $content = "<div class='alert-danger'>$message</div>";
1977          // Check whether debug is set.
1978          $debug = (!empty($CFG->debug) && $CFG->debug >= DEBUG_DEVELOPER);
1979          // Also check we have it set in the config file. This occurs if the method to read the config table from the
1980          // database fails, reading from the config table is the first database interaction we have.
1981          $debug = $debug || (!empty($CFG->config_php_settings['debug'])  && $CFG->config_php_settings['debug'] >= DEBUG_DEVELOPER );
1982          if ($debug) {
1983              if (!empty($debuginfo)) {
1984                  // Remove all nasty JS.
1985                  if (function_exists('s')) { // Function may be not available for some early errors.
1986                      $debuginfo = s($debuginfo);
1987                  } else {
1988                      // Because weblib is not available for these early errors, we
1989                      // just duplicate s() code here to be safe.
1990                      $debuginfo = preg_replace('/&amp;#(\d+|x[0-9a-f]+);/i', '&#$1;',
1991                      htmlspecialchars($debuginfo, ENT_QUOTES | ENT_HTML401 | ENT_SUBSTITUTE));
1992                  }
1993                  $debuginfo = str_replace("\n", '<br />', $debuginfo); // keep newlines
1994                  $content .= '<div class="notifytiny">Debug info: ' . $debuginfo . '</div>';
1995              }
1996              if (!empty($backtrace)) {
1997                  $content .= '<div class="notifytiny">Stack trace: ' . format_backtrace($backtrace, false) . '</div>';
1998              }
1999          }
2000  
2001          return $content;
2002      }
2003  
2004      /**
2005       * This function should only be called by this class, or from exception handlers
2006       * @static
2007       * @param string $message error message
2008       * @param string $moreinfourl (ignored in early errors)
2009       * @param string $link (ignored in early errors)
2010       * @param array $backtrace
2011       * @param string $debuginfo extra information for developers
2012       * @return string
2013       */
2014      public static function early_error($message, $moreinfourl, $link, $backtrace, $debuginfo = null, $errorcode = null) {
2015          global $CFG;
2016  
2017          if (CLI_SCRIPT) {
2018              echo "!!! $message !!!\n";
2019              if (!empty($CFG->debug) and $CFG->debug >= DEBUG_DEVELOPER) {
2020                  if (!empty($debuginfo)) {
2021                      echo "\nDebug info: $debuginfo";
2022                  }
2023                  if (!empty($backtrace)) {
2024                      echo "\nStack trace: " . format_backtrace($backtrace, true);
2025                  }
2026              }
2027              return;
2028  
2029          } else if (AJAX_SCRIPT) {
2030              $e = new stdClass();
2031              $e->error      = $message;
2032              $e->stacktrace = NULL;
2033              $e->debuginfo  = NULL;
2034              if (!empty($CFG->debug) and $CFG->debug >= DEBUG_DEVELOPER) {
2035                  if (!empty($debuginfo)) {
2036                      $e->debuginfo = $debuginfo;
2037                  }
2038                  if (!empty($backtrace)) {
2039                      $e->stacktrace = format_backtrace($backtrace, true);
2040                  }
2041              }
2042              $e->errorcode  = $errorcode;
2043              @header('Content-Type: application/json; charset=utf-8');
2044              echo json_encode($e);
2045              return;
2046          }
2047  
2048          // In the name of protocol correctness, monitoring and performance
2049          // profiling, set the appropriate error headers for machine consumption.
2050          $protocol = (isset($_SERVER['SERVER_PROTOCOL']) ? $_SERVER['SERVER_PROTOCOL'] : 'HTTP/1.0');
2051          @header($protocol . ' 500 Internal Server Error');
2052  
2053          // better disable any caching
2054          @header('Content-Type: text/html; charset=utf-8');
2055          @header('X-UA-Compatible: IE=edge');
2056          @header('Cache-Control: no-store, no-cache, must-revalidate');
2057          @header('Cache-Control: post-check=0, pre-check=0', false);
2058          @header('Pragma: no-cache');
2059          @header('Expires: Mon, 20 Aug 1969 09:23:00 GMT');
2060          @header('Last-Modified: ' . gmdate('D, d M Y H:i:s') . ' GMT');
2061  
2062          if (function_exists('get_string')) {
2063              $strerror = get_string('error');
2064          } else {
2065              $strerror = 'Error';
2066          }
2067  
2068          $content = self::early_error_content($message, $moreinfourl, $link, $backtrace, $debuginfo);
2069  
2070          return self::plain_page($strerror, $content);
2071      }
2072  
2073      /**
2074       * Early notification message
2075       * @static
2076       * @param string $message
2077       * @param string $classes usually notifyproblem or notifysuccess
2078       * @return string
2079       */
2080      public static function early_notification($message, $classes = 'notifyproblem') {
2081          return '<div class="' . $classes . '">' . $message . '</div>';
2082      }
2083  
2084      /**
2085       * Page should redirect message.
2086       * @static
2087       * @param string $encodedurl redirect url
2088       * @return string
2089       */
2090      public static function plain_redirect_message($encodedurl) {
2091          $message = '<div style="margin-top: 3em; margin-left:auto; margin-right:auto; text-align:center;">' . get_string('pageshouldredirect') . '<br /><a href="'.
2092                  $encodedurl .'">'. get_string('continue') .'</a></div>';
2093          return self::plain_page(get_string('redirect'), $message);
2094      }
2095  
2096      /**
2097       * Early redirection page, used before full init of $PAGE global
2098       * @static
2099       * @param string $encodedurl redirect url
2100       * @param string $message redirect message
2101       * @param int $delay time in seconds
2102       * @return string redirect page
2103       */
2104      public static function early_redirect_message($encodedurl, $message, $delay) {
2105          $meta = '<meta http-equiv="refresh" content="'. $delay .'; url='. $encodedurl .'" />';
2106          $content = self::early_error_content($message, null, null, null);
2107          $content .= self::plain_redirect_message($encodedurl);
2108  
2109          return self::plain_page(get_string('redirect'), $content, $meta);
2110      }
2111  
2112      /**
2113       * Output basic html page.
2114       * @static
2115       * @param string $title page title
2116       * @param string $content page content
2117       * @param string $meta meta tag
2118       * @return string html page
2119       */
2120      public static function plain_page($title, $content, $meta = '') {
2121          global $CFG;
2122  
2123          if (function_exists('get_string') && function_exists('get_html_lang')) {
2124              $htmllang = get_html_lang();
2125          } else {
2126              $htmllang = '';
2127          }
2128  
2129          $footer = '';
2130          if (function_exists('get_performance_info')) { // Function may be not available for some early errors.
2131              if (MDL_PERF_TEST) {
2132                  $perfinfo = get_performance_info();
2133                  $footer = '<footer>' . $perfinfo['html'] . '</footer>';
2134              }
2135          }
2136  
2137          ob_start();
2138          include($CFG->dirroot . '/error/plainpage.php');
2139          $html = ob_get_contents();
2140          ob_end_clean();
2141  
2142          return $html;
2143      }
2144  }