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         $errordocroot = $CFG->errordocroot;
 484     } else if (!empty($CFG->docroot)) {
 485         $errordocroot = $CFG->docroot;
 486     } else {
 487         $errordocroot = 'http://docs.moodle.org';
 488     }
 489     if ($module === 'error') {
 490         $modulelink = 'moodle';
 491     } else {
 492         $modulelink = $module;
 493     }
 494     $moreinfourl = $errordocroot . '/en/error/' . $modulelink . '/' . $errorcode;
 495
 496     if (empty($link)) {
 497         if (!empty($SESSION->fromurl)) {
 498             $link = $SESSION->fromurl;
 499             unset($SESSION->fromurl);
 500         } else {
 501             $link = $CFG->wwwroot .'/';
 502         }
 503     }
 504
 505     $info = new stdClass();
 506     $info->message     = $message;
 507     $info->errorcode   = $errorcode;
 508     $info->backtrace   = $backtrace;
 509     $info->link        = $link;
 510     $info->moreinfourl = $moreinfourl;
 511     $info->a           = $a;
 512     $info->debuginfo   = $debuginfo;
 513
 514     return $info;
 515 }
 516
 517 /**
 518  * Formats a backtrace ready for output.
 519  *
 520  * @param array $callers backtrace array, as returned by debug_backtrace().
 521  * @param boolean $plaintext if false, generates HTML, if true generates plain text.
 522  * @return string formatted backtrace, ready for output.
 523  */
 524 function format_backtrace($callers, $plaintext = false) {
 525     // do not use $CFG->dirroot because it might not be available in destructors
 526     $dirroot = dirname(dirname(__FILE__));
 527
 528     if (empty($callers)) {
 529         return '';
 530     }
 531
 532     $from = $plaintext ? '' : '<ul style="text-align: left">';
 533     foreach ($callers as $caller) {
 534         if (!isset($caller['line'])) {
 535             $caller['line'] = '?'; // probably call_user_func()
 536         }
 537         if (!isset($caller['file'])) {
 538             $caller['file'] = 'unknownfile'; // probably call_user_func()
 539         }
 540         $from .= $plaintext ? '* ' : '<li>';
 541         $from .= 'line ' . $caller['line'] . ' of ' . str_replace($dirroot, '', $caller['file']);
 542         if (isset($caller['function'])) {
 543             $from .= ': call to ';
 544             if (isset($caller['class'])) {
 545                 $from .= $caller['class'] . $caller['type'];
 546             }
 547             $from .= $caller['function'] . '()';
 548         } else if (isset($caller['exception'])) {
 549             $from .= ': '.$caller['exception'].' thrown';
 550         }
 551         $from .= $plaintext ? "\n" : '</li>';
 552     }
 553     $from .= $plaintext ? '' : '</ul>';
 554
 555     return $from;
 556 }
 557
 558 /**
 559  * This function makes the return value of ini_get consistent if you are
 560  * setting server directives through the .htaccess file in apache.
 561  *
 562  * Current behavior for value set from php.ini On = 1, Off = [blank]
 563  * Current behavior for value set from .htaccess On = On, Off = Off
 564  * Contributed by jdell @ unr.edu
 565  *
 566  * @param string $ini_get_arg The argument to get
 567  * @return bool True for on false for not
 568  */
 569 function ini_get_bool($ini_get_arg) {
 570     $temp = ini_get($ini_get_arg);
 571
 572     if ($temp == '1' or strtolower($temp) == 'on') {
 573         return true;
 574     }
 575     return false;
 576 }
 577
 578 /**
 579  * This function verifies the sanity of PHP configuration
 580  * and stops execution if anything critical found.
 581  */
 582 function setup_validate_php_configuration() {
 583    // this must be very fast - no slow checks here!!!
 584
 585    if (ini_get_bool('register_globals')) {
 586        print_error('globalswarning', 'admin');
 587    }
 588    if (ini_get_bool('session.auto_start')) {
 589        print_error('sessionautostartwarning', 'admin');
 590    }
 591    if (ini_get_bool('magic_quotes_runtime')) {
 592        print_error('fatalmagicquotesruntime', 'admin');
 593    }
 594 }
 595
 596 /**
 597  * Initialise global $CFG variable
 598  * @return void
 599  */
 600 function initialise_cfg() {
 601     global $CFG, $DB;
 602
 603     try {
 604         if ($DB) {
 605             $localcfg = $DB->get_records_menu('config', array(), '', 'name,value');
 606             foreach ($localcfg as $name=>$value) {
 607                 if (property_exists($CFG, $name)) {
 608                     // config.php settings always take precedence
 609                     continue;
 610                 }
 611                 $CFG->{$name} = $value;
 612             }
 613         }
 614     } catch (dml_read_exception $e) {
 615         // most probably empty db, going to install soon
 616     }
 617 }
 618
 619 /**
 620  * Initialises $FULLME and friends. Private function. Should only be called from
 621  * setup.php.
 622  */
 623 function initialise_fullme() {
 624     global $CFG, $FULLME, $ME, $SCRIPT, $FULLSCRIPT;
 625
 626     // Detect common config error.
 627     if (substr($CFG->wwwroot, -1) == '/') {
 628         print_error('wwwrootslash', 'error');
 629     }
 630
 631     if (CLI_SCRIPT) {
 632         initialise_fullme_cli();
 633         return;
 634     }
 635
 636     $wwwroot = parse_url($CFG->wwwroot);
 637     if (!isset($wwwroot['path'])) {
 638         $wwwroot['path'] = '';
 639     }
 640     $wwwroot['path'] .= '/';
 641
 642     $rurl = setup_get_remote_url();
 643
 644     // Check that URL is under $CFG->wwwroot.
 645     if (strpos($rurl['path'], $wwwroot['path']) === 0) {
 646         $SCRIPT = substr($rurl['path'], strlen($wwwroot['path'])-1);
 647     } else {
 648         // Probably some weird external script
 649         $SCRIPT = $FULLSCRIPT = $FULLME = $ME = null;
 650         return;
 651     }
 652
 653     // $CFG->sslproxy specifies if external SSL appliance is used
 654     // (That is, the Moodle server uses http, with an external box translating everything to https).
 655     if (empty($CFG->sslproxy)) {
 656         if ($rurl['scheme'] === 'http' and $wwwroot['scheme'] === 'https') {
 657             print_error('sslonlyaccess', 'error');
 658         }
 659     } else {
 660         if ($wwwroot['scheme'] !== 'https') {
 661             throw new coding_exception('Must use https address in wwwroot when ssl proxy enabled!');
 662         }
 663         $rurl['scheme'] = 'https'; // make moodle believe it runs on https, squid or something else it doing it
 664     }
 665
 666     // $CFG->reverseproxy specifies if reverse proxy server used.
 667     // Used in load balancing scenarios.
 668     // Do not abuse this to try to solve lan/wan access problems!!!!!
 669     if (empty($CFG->reverseproxy)) {
 670         if (($rurl['host'] != $wwwroot['host']) or
 671                 (!empty($wwwroot['port']) and $rurl['port'] != $wwwroot['port'])) {
 672             // Explain the problem and redirect them to the right URL
 673             if (!defined('NO_MOODLE_COOKIES')) {
 674                 define('NO_MOODLE_COOKIES', true);
 675             }
 676             redirect($CFG->wwwroot, get_string('wwwrootmismatch', 'error', $CFG->wwwroot), 3);
 677         }
 678     }
 679
 680     // hopefully this will stop all those "clever" admins trying to set up moodle
 681     // with two different addresses in intranet and Internet
 682     if (!empty($CFG->reverseproxy) && $rurl['host'] == $wwwroot['host']) {
 683         print_error('reverseproxyabused', 'error');
 684     }
 685
 686     $hostandport = $rurl['scheme'] . '://' . $wwwroot['host'];
 687     if (!empty($wwwroot['port'])) {
 688         $hostandport .= ':'.$wwwroot['port'];
 689     }
 690
 691     $FULLSCRIPT = $hostandport . $rurl['path'];
 692     $FULLME = $hostandport . $rurl['fullpath'];
 693     $ME = $rurl['fullpath'];
 694 }
 695
 696 /**
 697  * Initialises $FULLME and friends for command line scripts.
 698  * This is a private method for use by initialise_fullme.
 699  */
 700 function initialise_fullme_cli() {
 701     global $CFG, $FULLME, $ME, $SCRIPT, $FULLSCRIPT;
 702
 703     // Urls do not make much sense in CLI scripts
 704     $backtrace = debug_backtrace();
 705     $topfile = array_pop($backtrace);
 706     $topfile = realpath($topfile['file']);
 707     $dirroot = realpath($CFG->dirroot);
 708
 709     if (strpos($topfile, $dirroot) !== 0) {
 710         // Probably some weird external script
 711         $SCRIPT = $FULLSCRIPT = $FULLME = $ME = null;
 712     } else {
 713         $relativefile = substr($topfile, strlen($dirroot));
 714         $relativefile = str_replace('\\', '/', $relativefile); // Win fix
 715         $SCRIPT = $FULLSCRIPT = $relativefile;
 716         $FULLME = $ME = null;
 717     }
 718 }
 719
 720 /**
 721  * Get the URL that PHP/the web server thinks it is serving. Private function
 722  * used by initialise_fullme. In your code, use $PAGE->url, $SCRIPT, etc.
 723  * @return array in the same format that parse_url returns, with the addition of
 724  *      a 'fullpath' element, which includes any slasharguments path.
 725  */
 726 function setup_get_remote_url() {
 727     $rurl = array();
 728     list($rurl['host']) = explode(':', $_SERVER['HTTP_HOST']);
 729     $rurl['port'] = $_SERVER['SERVER_PORT'];
 730     $rurl['path'] = $_SERVER['SCRIPT_NAME']; // Script path without slash arguments
 731     $rurl['scheme'] = (empty($_SERVER['HTTPS']) or $_SERVER['HTTPS'] === 'off' or $_SERVER['HTTPS'] === 'Off' or $_SERVER['HTTPS'] === 'OFF') ? 'http' : 'https';
 732
 733     if (stripos($_SERVER['SERVER_SOFTWARE'], 'apache') !== false) {
 734         //Apache server
 735         $rurl['fullpath'] = $_SERVER['REQUEST_URI'];
 736
 737     } else if (stripos($_SERVER['SERVER_SOFTWARE'], 'iis') !== false) {
 738         //IIS - needs a lot of tweaking to make it work
 739         $rurl['fullpath'] = $_SERVER['SCRIPT_NAME'];
 740
 741         // NOTE: ignore PATH_INFO because it is incorrectly encoded using 8bit filesystem legacy encoding in IIS
 742         //       since 2.0 we rely on iis rewrite extenssion like Helicon ISAPI_rewrite
 743         //       example rule: RewriteRule ^([^\?]+?\.php)(\/.+)$ $1\?file=$2 [QSA]
 744
 745         if ($_SERVER['QUERY_STRING'] != '') {
 746             $rurl['fullpath'] .= '?'.$_SERVER['QUERY_STRING'];
 747         }
 748         $_SERVER['REQUEST_URI'] = $rurl['fullpath']; // extra IIS compatibility
 749
 750 /* NOTE: following servers are not fully tested! */
 751
 752     } else if (stripos($_SERVER['SERVER_SOFTWARE'], 'lighttpd') !== false) {
 753         //lighttpd - not officially supported
 754         $rurl['fullpath'] = $_SERVER['REQUEST_URI']; // TODO: verify this is always properly encoded
 755
 756     } else if (stripos($_SERVER['SERVER_SOFTWARE'], 'nginx') !== false) {
 757         //nginx - not officially supported
 758         if (!isset($_SERVER['SCRIPT_NAME'])) {
 759             die('Invalid server configuration detected, please try to add "fastcgi_param SCRIPT_NAME $fastcgi_script_name;" to the nginx server configuration.');
 760         }
 761         $rurl['fullpath'] = $_SERVER['REQUEST_URI']; // TODO: verify this is always properly encoded
 762
 763      } else if (stripos($_SERVER['SERVER_SOFTWARE'], 'cherokee') !== false) {
 764          //cherokee - not officially supported
 765          $rurl['fullpath'] = $_SERVER['REQUEST_URI']; // TODO: verify this is always properly encoded
 766
 767      } else if (stripos($_SERVER['SERVER_SOFTWARE'], 'zeus') !== false) {
 768          //zeus - not officially supported
 769          $rurl['fullpath'] = $_SERVER['REQUEST_URI']; // TODO: verify this is always properly encoded
 770
 771     } else if (stripos($_SERVER['SERVER_SOFTWARE'], 'LiteSpeed') !== false) {
 772         //LiteSpeed - not officially supported
 773         $rurl['fullpath'] = $_SERVER['REQUEST_URI']; // TODO: verify this is always properly encoded
 774
 775     } else if ($_SERVER['SERVER_SOFTWARE'] === 'HTTPD') {
 776         //obscure name found on some servers - this is definitely not supported
 777         $rurl['fullpath'] = $_SERVER['REQUEST_URI']; // TODO: verify this is always properly encoded
 778
 779      } else {
 780         throw new moodle_exception('unsupportedwebserver', 'error', '', $_SERVER['SERVER_SOFTWARE']);
 781     }
 782
 783     // sanitize the url a bit more, the encoding style may be different in vars above
 784     $rurl['fullpath'] = str_replace('"', '%22', $rurl['fullpath']);
 785     $rurl['fullpath'] = str_replace('\'', '%27', $rurl['fullpath']);
 786
 787     return $rurl;
 788 }
 789
 790 /**
 791  * Initializes our performance info early.
 792  *
 793  * Pairs up with get_performance_info() which is actually
 794  * in moodlelib.php. This function is here so that we can
 795  * call it before all the libs are pulled in.
 796  *
 797  * @uses $PERF
 798  */
 799 function init_performance_info() {
 800
 801     global $PERF, $CFG, $USER;
 802
 803     $PERF = new stdClass();
 804     $PERF->logwrites = 0;
 805     if (function_exists('microtime')) {
 806         $PERF->starttime = microtime();
 807     }
 808     if (function_exists('memory_get_usage')) {
 809         $PERF->startmemory = memory_get_usage();
 810     }
 811     if (function_exists('posix_times')) {
 812         $PERF->startposixtimes = posix_times();
 813     }
 814     if (function_exists('apd_set_pprof_trace')) {
 815         // APD profiling
 816         if ($USER->id > 0 && $CFG->perfdebug >= 15) {
 817             $tempdir = $CFG->dataroot . '/temp/profile/' . $USER->id;
 818             mkdir($tempdir);
 819             apd_set_pprof_trace($tempdir);
 820             $PERF->profiling = true;
 821         }
 822     }
 823 }
 824
 825 /**
 826  * Indicates whether we are in the middle of the initial Moodle install.
 827  *
 828  * Very occasionally it is necessary avoid running certain bits of code before the
 829  * Moodle installation has completed. The installed flag is set in admin/index.php
 830  * after Moodle core and all the plugins have been installed, but just before
 831  * the person doing the initial install is asked to choose the admin password.
 832  *
 833  * @return boolean true if the initial install is not complete.
 834  */
 835 function during_initial_install() {
 836     global $CFG;
 837     return empty($CFG->rolesactive);
 838 }
 839
 840 /**
 841  * Function to raise the memory limit to a new value.
 842  * Will respect the memory limit if it is higher, thus allowing
 843  * settings in php.ini, apache conf or command line switches
 844  * to override it.
 845  *
 846  * The memory limit should be expressed with a constant
 847  * MEMORY_STANDARD, MEMORY_EXTRA or MEMORY_HUGE.
 848  * It is possible to use strings or integers too (eg:'128M').
 849  *
 850  * @param mixed $newlimit the new memory limit
 851  * @return bool success
 852  */
 853 function raise_memory_limit($newlimit) {
 854     global $CFG;
 855
 856     if ($newlimit == MEMORY_UNLIMITED) {
 857         ini_set('memory_limit', -1);
 858         return true;
 859
 860     } else if ($newlimit == MEMORY_STANDARD) {
 861         if (PHP_INT_SIZE > 4) {
 862             $newlimit = get_real_size('128M'); // 64bit needs more memory
 863         } else {
 864             $newlimit = get_real_size('96M');
 865         }
 866
 867     } else if ($newlimit == MEMORY_EXTRA) {
 868         if (PHP_INT_SIZE > 4) {
 869             $newlimit = get_real_size('384M'); // 64bit needs more memory
 870         } else {
 871             $newlimit = get_real_size('256M');
 872         }
 873         if (!empty($CFG->extramemorylimit)) {
 874             $extra = get_real_size($CFG->extramemorylimit);
 875             if ($extra > $newlimit) {
 876                 $newlimit = $extra;
 877             }
 878         }
 879
 880     } else if ($newlimit == MEMORY_HUGE) {
 881         $newlimit = get_real_size('2G');
 882
 883     } else {
 884         $newlimit = get_real_size($newlimit);
 885     }
 886
 887     if ($newlimit <= 0) {
 888         debugging('Invalid memory limit specified.');
 889         return false;
 890     }
 891
 892     $cur = ini_get('memory_limit');
 893     if (empty($cur)) {
 894         // if php is compiled without --enable-memory-limits
 895         // apparently memory_limit is set to ''
 896         $cur = 0;
 897     } else {
 898         if ($cur == -1){
 899             return true; // unlimited mem!
 900         }
 901         $cur = get_real_size($cur);
 902     }
 903
 904     if ($newlimit > $cur) {
 905         ini_set('memory_limit', $newlimit);
 906         return true;
 907     }
 908     return false;
 909 }
 910
 911 /**
 912  * Function to reduce the memory limit to a new value.
 913  * Will respect the memory limit if it is lower, thus allowing
 914  * settings in php.ini, apache conf or command line switches
 915  * to override it
 916  *
 917  * The memory limit should be expressed with a string (eg:'64M')
 918  *
 919  * @param string $newlimit the new memory limit
 920  * @return bool
 921  */
 922 function reduce_memory_limit($newlimit) {
 923     if (empty($newlimit)) {
 924         return false;
 925     }
 926     $cur = ini_get('memory_limit');
 927     if (empty($cur)) {
 928         // if php is compiled without --enable-memory-limits
 929         // apparently memory_limit is set to ''
 930         $cur = 0;
 931     } else {
 932         if ($cur == -1){
 933             return true; // unlimited mem!
 934         }
 935         $cur = get_real_size($cur);
 936     }
 937
 938     $new = get_real_size($newlimit);
 939     // -1 is smaller, but it means unlimited
 940     if ($new < $cur && $new != -1) {
 941         ini_set('memory_limit', $newlimit);
 942         return true;
 943     }
 944     return false;
 945 }
 946
 947 /**
 948  * Converts numbers like 10M into bytes.
 949  *
 950  * @param string $size The size to be converted
 951  * @return int
 952  */
 953 function get_real_size($size = 0) {
 954     if (!$size) {
 955         return 0;
 956     }
 957     $scan = array();
 958     $scan['GB'] = 1073741824;
 959     $scan['Gb'] = 1073741824;
 960     $scan['G'] = 1073741824;
 961     $scan['MB'] = 1048576;
 962     $scan['Mb'] = 1048576;
 963     $scan['M'] = 1048576;
 964     $scan['m'] = 1048576;
 965     $scan['KB'] = 1024;
 966     $scan['Kb'] = 1024;
 967     $scan['K'] = 1024;
 968     $scan['k'] = 1024;
 969
 970     while (list($key) = each($scan)) {
 971         if ((strlen($size)>strlen($key))&&(substr($size, strlen($size) - strlen($key))==$key)) {
 972             $size = substr($size, 0, strlen($size) - strlen($key)) * $scan[$key];
 973             break;
 974         }
 975     }
 976     return $size;
 977 }
 978
 979 /**
 980  * Try to disable all output buffering and purge
 981  * all headers.
 982  *
 983  * @private to be called only from lib/setup.php !
 984  * @return void
 985  */
 986 function disable_output_buffering() {
 987     $olddebug = error_reporting(0);
 988
 989     // disable compression, it would prevent closing of buffers
 990     if (ini_get_bool('zlib.output_compression')) {
 991         ini_set('zlib.output_compression', 'Off');
 992     }
 993
 994     // try to flush everything all the time
 995     ob_implicit_flush(true);
 996
 997     // close all buffers if possible and discard any existing output
 998     // this can actually work around some whitespace problems in config.php
 999     while(ob_get_level()) {
1000         if (!ob_end_clean()) {
1001             // prevent infinite loop when buffer can not be closed
1002             break;
1003         }
1004     }
1005
1006     error_reporting($olddebug);
1007 }
1008
1009 /**
1010  * Check whether a major upgrade is needed. That is defined as an upgrade that
1011  * changes something really fundamental in the database, so nothing can possibly
1012  * work until the database has been updated, and that is defined by the hard-coded
1013  * version number in this function.
1014  */
1015 function redirect_if_major_upgrade_required() {
1016     global $CFG;
1017     $lastmajordbchanges = 2010111700;
1018     if (empty($CFG->version) or (int)$CFG->version < $lastmajordbchanges or
1019             during_initial_install() or !empty($CFG->adminsetuppending)) {
1020         try {
1021             @session_get_instance()->terminate_current();
1022         } catch (Exception $e) {
1023             // Ignore any errors, redirect to upgrade anyway.
1024         }
1025         $url = $CFG->wwwroot . '/' . $CFG->admin . '/index.php';
1026         @header($_SERVER['SERVER_PROTOCOL'] . ' 303 See Other');
1027         @header('Location: ' . $url);
1028         echo bootstrap_renderer::plain_redirect_message(htmlspecialchars($url));
1029         exit;
1030     }
1031 }
1032
1033 /**
1034  * Function to check if a directory exists and by default create it if not exists.
1035  *
1036  * Previously this was accepting paths only from dataroot, but we now allow
1037  * files outside of dataroot if you supply custom paths for some settings in config.php.
1038  * This function does not verify that the directory is writable.
1039  *
1040  * @param string $dir absolute directory path
1041  * @param boolean $create directory if does not exist
1042  * @param boolean $recursive create directory recursively
1043  * @return boolean true if directory exists or created, false otherwise
1044  */
1045 function check_dir_exists($dir, $create = true, $recursive = true) {
1046     global $CFG;
1047
1048     umask(0000); // just in case some evil code changed it
1049
1050     if (is_dir($dir)) {
1051         return true;
1052     }
1053
1054     if (!$create) {
1055         return false;
1056     }
1057
1058     return mkdir($dir, $CFG->directorypermissions, $recursive);
1059 }
1060
1061 /**
1062  * Create a directory in dataroot and make sure it is writable.
1063  *
1064  * @param string $directory  a string of directory names under $CFG->dataroot eg  temp/something
1065  * @param bool $exceptiononerror throw exception if error encountered
1066  * @return string|false Returns full path to directory if successful, false if not; may throw exception
1067  */
1068 function make_upload_directory($directory, $exceptiononerror = true) {
1069     global $CFG;
1070
1071     // Make sure a .htaccess file is here, JUST IN CASE the files area is in the open and .htaccess is supported
1072     if (!file_exists("$CFG->dataroot/.htaccess")) {
1073         if ($handle = fopen("$CFG->dataroot/.htaccess", 'w')) {   // For safety
1074             @fwrite($handle, "deny from all\r\nAllowOverride None\r\nNote: this file is broken intentionally, we do not want anybody to undo it in subdirectory!\r\n");
1075             @fclose($handle);
1076         }
1077     }
1078
1079     $dir = "$CFG->dataroot/$directory";
1080
1081     if (file_exists($dir) and !is_dir($dir)) {
1082         if ($exceptiononerror) {
1083             throw new coding_exception($dir.' directory can not be created, file with the same name already exists.');
1084         } else {
1085             return false;
1086         }
1087     }
1088
1089     umask(0000); // just in case some evil code changed it
1090
1091     if (!file_exists($dir)) {
1092         if (!mkdir($dir, $CFG->directorypermissions, true)) {
1093             if ($exceptiononerror) {
1094                 throw new invalid_dataroot_permissions($dir.' can not be created, check permissions.');
1095             } else {
1096                 return false;
1097             }
1098         }
1099     }
1100
1101     if (!is_writable($dir)) {
1102         if ($exceptiononerror) {
1103             throw new invalid_dataroot_permissions($dir.' is not writable, check permissions.');
1104         } else {
1105             return false;
1106         }
1107     }
1108
1109     return $dir;
1110 }
1111
1112 function init_memcached() {
1113     global $CFG, $MCACHE;
1114
1115     include_once($CFG->libdir . '/memcached.class.php');
1116     $MCACHE = new memcached;
1117     if ($MCACHE->status()) {
1118         return true;
1119     }
1120     unset($MCACHE);
1121     return false;
1122 }
1123
1124 function init_eaccelerator() {
1125     global $CFG, $MCACHE;
1126
1127     include_once($CFG->libdir . '/eaccelerator.class.php');
1128     $MCACHE = new eaccelerator;
1129     if ($MCACHE->status()) {
1130         return true;
1131     }
1132     unset($MCACHE);
1133     return false;
1134 }
1135
1136 /**
1137  * Checks if current user is a web crawler.
1138  *
1139  * This list can not be made complete, this is not a security
1140  * restriction, we make the list only to help these sites
1141  * especially when automatic guest login is disabled.
1142  *
1143  * If admin needs security they should enable forcelogin
1144  * and disable guest access!!
1145  *
1146  * @return bool
1147  */
1148 function is_web_crawler() {
1149     if (!empty($_SERVER['HTTP_USER_AGENT'])) {
1150         if (strpos($_SERVER['HTTP_USER_AGENT'], 'Googlebot') !== false ) {
1151             return true;
1152         } else if (strpos($_SERVER['HTTP_USER_AGENT'], 'google.com') !== false ) { // Google
1153             return true;
1154         } else if (strpos($_SERVER['HTTP_USER_AGENT'], 'Yahoo! Slurp') !== false ) {  // Yahoo
1155             return true;
1156         } else if (strpos($_SERVER['HTTP_USER_AGENT'], '[ZSEBOT]') !== false ) {  // Zoomspider
1157             return true;
1158         } else if (strpos($_SERVER['HTTP_USER_AGENT'], 'MSNBOT') !== false ) {  // MSN Search
1159             return true;
1160         } else if (strpos($_SERVER['HTTP_USER_AGENT'], 'Yandex') !== false ) {
1161             return true;
1162         } else if (strpos($_SERVER['HTTP_USER_AGENT'], 'AltaVista') !== false ) {
1163             return true;
1164         }
1165     }
1166     return false;
1167 }
1168
1169 /**
1170  * This class solves the problem of how to initialise $OUTPUT.
1171  *
1172  * The problem is caused be two factors
1173  * <ol>
1174  * <li>On the one hand, we cannot be sure when output will start. In particular,
1175  * an error, which needs to be displayed, could be thrown at any time.</li>
1176  * <li>On the other hand, we cannot be sure when we will have all the information
1177  * necessary to correctly initialise $OUTPUT. $OUTPUT depends on the theme, which
1178  * (potentially) depends on the current course, course categories, and logged in user.
1179  * It also depends on whether the current page requires HTTPS.</li>
1180  * </ol>
1181  *
1182  * So, it is hard to find a single natural place during Moodle script execution,
1183  * which we can guarantee is the right time to initialise $OUTPUT. Instead we
1184  * adopt the following strategy
1185  * <ol>
1186  * <li>We will initialise $OUTPUT the first time it is used.</li>
1187  * <li>If, after $OUTPUT has been initialised, the script tries to change something
1188  * that $OUTPUT depends on, we throw an exception making it clear that the script
1189  * did something wrong.
1190  * </ol>
1191  *
1192  * The only problem with that is, how do we initialise $OUTPUT on first use if,
1193  * it is going to be used like $OUTPUT->somthing(...)? Well that is where this
1194  * class comes in. Initially, we set up $OUTPUT = new bootstrap_renderer(). Then,
1195  * when any method is called on that object, we initialise $OUTPUT, and pass the call on.
1196  *
1197  * Note that this class is used before lib/outputlib.php has been loaded, so we
1198  * must be careful referring to classes/functions from there, they may not be
1199  * defined yet, and we must avoid fatal errors.
1200  *
1201  * @copyright 2009 Tim Hunt
1202  * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
1203  * @since     Moodle 2.0
1204  */
1205 class bootstrap_renderer {
1206     /**
1207      * Handles re-entrancy. Without this, errors or debugging output that occur
1208      * during the initialisation of $OUTPUT, cause infinite recursion.
1209      * @var boolean
1210      */
1211     protected $initialising = false;
1212
1213     /**
1214      * Have we started output yet?
1215      * @return boolean true if the header has been printed.
1216      */
1217     public function has_started() {
1218         return false;
1219     }
1220
1221     public function __call($method, $arguments) {
1222         global $OUTPUT, $PAGE;
1223
1224         $recursing = false;
1225         if ($method == 'notification') {
1226             // Catch infinite recursion caused by debugging output during print_header.
1227             $backtrace = debug_backtrace();
1228             array_shift($backtrace);
1229             array_shift($backtrace);
1230             $recursing = is_early_init($backtrace);
1231         }
1232
1233         $earlymethods = array(
1234             'fatal_error' => 'early_error',
1235             'notification' => 'early_notification',
1236         );
1237
1238         // If lib/outputlib.php has been loaded, call it.
1239         if (!empty($PAGE) && !$recursing) {
1240             if (array_key_exists($method, $earlymethods)) {
1241                 //prevent PAGE->context warnings - exceptions might appear before we set any context
1242                 $PAGE->set_context(null);
1243             }
1244             $PAGE->initialise_theme_and_output();
1245             return call_user_func_array(array($OUTPUT, $method), $arguments);
1246         }
1247
1248         $this->initialising = true;
1249
1250         // Too soon to initialise $OUTPUT, provide a couple of key methods.
1251         if (array_key_exists($method, $earlymethods)) {
1252             return call_user_func_array(array('bootstrap_renderer', $earlymethods[$method]), $arguments);
1253         }
1254
1255         throw new coding_exception('Attempt to start output before enough information is known to initialise the theme.');
1256     }
1257
1258     /**
1259      * Returns nicely formatted error message in a div box.
1260      * @return string
1261      */
1262     public static function early_error_content($message, $moreinfourl, $link, $backtrace, $debuginfo = null) {
1263         global $CFG;
1264
1265         $content = '<div style="margin-top: 6em; margin-left:auto; margin-right:auto; color:#990000; text-align:center; font-size:large; border-width:1px;
1266 border-color:black; background-color:#ffffee; border-style:solid; border-radius: 20px; border-collapse: collapse;
1267 width: 80%; -moz-border-radius: 20px; padding: 15px">
1268 ' . $message . '
1269 </div>';
1270         if (!empty($CFG->debug) && $CFG->debug >= DEBUG_DEVELOPER) {
1271             if (!empty($debuginfo)) {
1272                 $debuginfo = s($debuginfo); // removes all nasty JS
1273                 $debuginfo = str_replace("\n", '<br />', $debuginfo); // keep newlines
1274                 $content .= '<div class="notifytiny">Debug info: ' . $debuginfo . '</div>';
1275             }
1276             if (!empty($backtrace)) {
1277                 $content .= '<div class="notifytiny">Stack trace: ' . format_backtrace($backtrace, false) . '</div>';
1278             }
1279         }
1280
1281         return $content;
1282     }
1283
1284     /**
1285      * This function should only be called by this class, or from exception handlers
1286      * @return string
1287      */
1288     public static function early_error($message, $moreinfourl, $link, $backtrace, $debuginfo = null) {
1289         global $CFG;
1290
1291         if (CLI_SCRIPT) {
1292             echo "!!! $message !!!\n";
1293             if (!empty($CFG->debug) and $CFG->debug >= DEBUG_DEVELOPER) {
1294                 if (!empty($debuginfo)) {
1295                     echo "\nDebug info: $debuginfo";
1296                 }
1297                 if (!empty($backtrace)) {
1298                     echo "\nStack trace: " . format_backtrace($backtrace, true);
1299                 }
1300             }
1301             return;
1302
1303         } else if (AJAX_SCRIPT) {
1304             $e = new stdClass();
1305             $e->error      = $message;
1306             $e->stacktrace = NULL;
1307             $e->debuginfo  = NULL;
1308             if (!empty($CFG->debug) and $CFG->debug >= DEBUG_DEVELOPER) {
1309                 if (!empty($debuginfo)) {
1310                     $e->debuginfo = $debuginfo;
1311                 }
1312                 if (!empty($backtrace)) {
1313                     $e->stacktrace = format_backtrace($backtrace, true);
1314                 }
1315             }
1316             @header('Content-Type: application/json; charset=utf-8');
1317             echo json_encode($e);
1318             return;
1319         }
1320
1321         // In the name of protocol correctness, monitoring and performance
1322         // profiling, set the appropriate error headers for machine consumption
1323         if (isset($_SERVER['SERVER_PROTOCOL'])) {
1324             // Avoid it with cron.php. Note that we assume it's HTTP/1.x
1325             // The 503 ode here means our Moodle does not work at all, the error happened too early
1326             @header($_SERVER['SERVER_PROTOCOL'] . ' 503 Service Unavailable');
1327         }
1328
1329         // better disable any caching
1330         @header('Content-Type: text/html; charset=utf-8');
1331         @header('Cache-Control: no-store, no-cache, must-revalidate');
1332         @header('Cache-Control: post-check=0, pre-check=0', false);
1333         @header('Pragma: no-cache');
1334         @header('Expires: Mon, 20 Aug 1969 09:23:00 GMT');
1335         @header('Last-Modified: ' . gmdate('D, d M Y H:i:s') . ' GMT');
1336
1337         if (function_exists('get_string')) {
1338             $strerror = get_string('error');
1339         } else {
1340             $strerror = 'Error';
1341         }
1342
1343         $content = self::early_error_content($message, $moreinfourl, $link, $backtrace, $debuginfo);
1344
1345         return self::plain_page($strerror, $content);
1346     }
1347
1348     public static function early_notification($message, $classes = 'notifyproblem') {
1349         return '<div class="' . $classes . '">' . $message . '</div>';
1350     }
1351
1352     public static function plain_redirect_message($encodedurl) {
1353         $message = '<p>' . get_string('pageshouldredirect') . '</p><p><a href="'.
1354                 $encodedurl .'">'. get_string('continue') .'</a></p>';
1355         return self::plain_page(get_string('redirect'), $message);
1356     }
1357
1358     protected static function plain_page($title, $content) {
1359         if (function_exists('get_string') && function_exists('get_html_lang')) {
1360             $htmllang = get_html_lang();
1361         } else {
1362             $htmllang = '';
1363         }
1364
1365         return '<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
1366 <html xmlns="http://www.w3.org/1999/xhtml" ' . $htmllang . '>
1367 <head>
1368 <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
1369 <title>' . $title . '</title>
1370 </head><body>' . $content . '</body></html>';
1371     }
1372 }