lib/setuplib.php

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