MediaWiki  1.28.0
MWExceptionHandler.php
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1 <?php
23 
29 
33  protected static $reservedMemory;
37  protected static $fatalErrorTypes = [
38  E_ERROR, E_PARSE, E_CORE_ERROR, E_COMPILE_ERROR, E_USER_ERROR,
39  /* HHVM's FATAL_ERROR level */ 16777217,
40  ];
44  protected static $handledFatalCallback = false;
45 
49  public static function installHandler() {
50  set_exception_handler( 'MWExceptionHandler::handleException' );
51  set_error_handler( 'MWExceptionHandler::handleError' );
52 
53  // Reserve 16k of memory so we can report OOM fatals
54  self::$reservedMemory = str_repeat( ' ', 16384 );
55  register_shutdown_function( 'MWExceptionHandler::handleFatalError' );
56  }
57 
62  protected static function report( $e ) {
63  try {
64  // Try and show the exception prettily, with the normal skin infrastructure
65  if ( $e instanceof MWException ) {
66  // Delegate to MWException until all subclasses are handled by
67  // MWExceptionRenderer and MWException::report() has been
68  // removed.
69  $e->report();
70  } else {
72  }
73  } catch ( Exception $e2 ) {
74  // Exception occurred from within exception handler
75  // Show a simpler message for the original exception,
76  // don't try to invoke report()
78  }
79  }
80 
89  public static function rollbackMasterChangesAndLog( $e ) {
90  $services = MediaWikiServices::getInstance();
91  if ( $services->isServiceDisabled( 'DBLoadBalancerFactory' ) ) {
92  return; // T147599
93  }
94 
95  $lbFactory = $services->getDBLoadBalancerFactory();
96  if ( $lbFactory->hasMasterChanges() ) {
97  $logger = LoggerFactory::getInstance( 'Bug56269' );
98  $logger->warning(
99  'Exception thrown with an uncommited database transaction: ' .
100  self::getLogMessage( $e ),
101  self::getLogContext( $e )
102  );
103  }
104  $lbFactory->rollbackMasterChanges( __METHOD__ );
105  }
106 
121  public static function handleException( $e ) {
122  try {
123  // Rollback DBs to avoid transaction notices. This may fail
124  // to rollback some DB due to connection issues or exceptions.
125  // However, any sane DB driver will rollback implicitly anyway.
126  self::rollbackMasterChangesAndLog( $e );
127  } catch ( DBError $e2 ) {
128  // If the DB is unreacheable, rollback() will throw an error
129  // and the error report() method might need messages from the DB,
130  // which would result in an exception loop. PHP may escalate such
131  // errors to "Exception thrown without a stack frame" fatals, but
132  // it's better to be explicit here.
133  self::logException( $e2 );
134  }
135 
136  self::logException( $e );
137  self::report( $e );
138 
139  // Exit value should be nonzero for the benefit of shell jobs
140  exit( 1 );
141  }
142 
161  public static function handleError(
162  $level, $message, $file = null, $line = null
163  ) {
164  if ( in_array( $level, self::$fatalErrorTypes ) ) {
165  return call_user_func_array(
166  'MWExceptionHandler::handleFatalError', func_get_args()
167  );
168  }
169 
170  // Map error constant to error name (reverse-engineer PHP error
171  // reporting)
172  switch ( $level ) {
173  case E_RECOVERABLE_ERROR:
174  $levelName = 'Error';
175  break;
176  case E_WARNING:
177  case E_CORE_WARNING:
178  case E_COMPILE_WARNING:
179  case E_USER_WARNING:
180  $levelName = 'Warning';
181  break;
182  case E_NOTICE:
183  case E_USER_NOTICE:
184  $levelName = 'Notice';
185  break;
186  case E_STRICT:
187  $levelName = 'Strict Standards';
188  break;
189  case E_DEPRECATED:
190  case E_USER_DEPRECATED:
191  $levelName = 'Deprecated';
192  break;
193  default:
194  $levelName = 'Unknown error';
195  break;
196  }
197 
198  $e = new ErrorException( "PHP $levelName: $message", 0, $level, $file, $line );
199  self::logError( $e, 'error' );
200 
201  // This handler is for logging only. Return false will instruct PHP
202  // to continue regular handling.
203  return false;
204  }
205 
227  public static function handleFatalError(
228  $level = null, $message = null, $file = null, $line = null,
229  $context = null, $trace = null
230  ) {
231  // Free reserved memory so that we have space to process OOM
232  // errors
233  self::$reservedMemory = null;
234 
235  if ( $level === null ) {
236  // Called as a shutdown handler, get data from error_get_last()
237  if ( static::$handledFatalCallback ) {
238  // Already called once (probably as an error handler callback
239  // under HHVM) so don't log again.
240  return false;
241  }
242 
243  $lastError = error_get_last();
244  if ( $lastError !== null ) {
245  $level = $lastError['type'];
246  $message = $lastError['message'];
247  $file = $lastError['file'];
248  $line = $lastError['line'];
249  } else {
250  $level = 0;
251  $message = '';
252  }
253  }
254 
255  if ( !in_array( $level, self::$fatalErrorTypes ) ) {
256  // Only interested in fatal errors, others should have been
257  // handled by MWExceptionHandler::handleError
258  return false;
259  }
260 
261  $msg = "[{exception_id}] PHP Fatal Error: {$message}";
262 
263  // Look at message to see if this is a class not found failure
264  // HHVM: Class undefined: foo
265  // PHP5: Class 'foo' not found
266  if ( preg_match( "/Class (undefined: \w+|'\w+' not found)/", $msg ) ) {
267  // @codingStandardsIgnoreStart Generic.Files.LineLength.TooLong
268  $msg = <<<TXT
269 {$msg}
270 
271 MediaWiki or an installed extension requires this class but it is not embedded directly in MediaWiki's git repository and must be installed separately by the end user.
272 
273 Please see <a href="https://www.mediawiki.org/wiki/Download_from_Git#Fetch_external_libraries">mediawiki.org</a> for help on installing the required components.
274 TXT;
275  // @codingStandardsIgnoreEnd
276  }
277 
278  // We can't just create an exception and log it as it is likely that
279  // the interpreter has unwound the stack already. If that is true the
280  // stacktrace we would get would be functionally empty. If however we
281  // have been called as an error handler callback *and* HHVM is in use
282  // we will have been provided with a useful stacktrace that we can
283  // log.
284  $trace = $trace ?: debug_backtrace();
285  $logger = LoggerFactory::getInstance( 'fatal' );
286  $logger->error( $msg, [
287  'exception' => [
288  'class' => 'ErrorException',
289  'message' => "PHP Fatal Error: {$message}",
290  'code' => $level,
291  'file' => $file,
292  'line' => $line,
293  'trace' => static::redactTrace( $trace ),
294  ],
295  'exception_id' => wfRandomString( 8 ),
296  ] );
297 
298  // Remember call so we don't double process via HHVM's fatal
299  // notifications and the shutdown hook behavior
300  static::$handledFatalCallback = true;
301  return false;
302  }
303 
314  public static function getRedactedTraceAsString( $e ) {
315  return self::prettyPrintTrace( self::getRedactedTrace( $e ) );
316  }
317 
326  public static function prettyPrintTrace( array $trace, $pad = '' ) {
327  $text = '';
328 
329  $level = 0;
330  foreach ( $trace as $level => $frame ) {
331  if ( isset( $frame['file'] ) && isset( $frame['line'] ) ) {
332  $text .= "{$pad}#{$level} {$frame['file']}({$frame['line']}): ";
333  } else {
334  // 'file' and 'line' are unset for calls via call_user_func
335  // (bug 55634) This matches behaviour of
336  // Exception::getTraceAsString to instead display "[internal
337  // function]".
338  $text .= "{$pad}#{$level} [internal function]: ";
339  }
340 
341  if ( isset( $frame['class'] ) && isset( $frame['type'] ) && isset( $frame['function'] ) ) {
342  $text .= $frame['class'] . $frame['type'] . $frame['function'];
343  } elseif ( isset( $frame['function'] ) ) {
344  $text .= $frame['function'];
345  } else {
346  $text .= 'NO_FUNCTION_GIVEN';
347  }
348 
349  if ( isset( $frame['args'] ) ) {
350  $text .= '(' . implode( ', ', $frame['args'] ) . ")\n";
351  } else {
352  $text .= "()\n";
353  }
354  }
355 
356  $level = $level + 1;
357  $text .= "{$pad}#{$level} {main}";
358 
359  return $text;
360  }
361 
373  public static function getRedactedTrace( $e ) {
374  return static::redactTrace( $e->getTrace() );
375  }
376 
387  public static function redactTrace( array $trace ) {
388  return array_map( function ( $frame ) {
389  if ( isset( $frame['args'] ) ) {
390  $frame['args'] = array_map( function ( $arg ) {
391  return is_object( $arg ) ? get_class( $arg ) : gettype( $arg );
392  }, $frame['args'] );
393  }
394  return $frame;
395  }, $trace );
396  }
397 
409  public static function getLogId( $e ) {
410  wfDeprecated( __METHOD__, '1.27' );
411  return WebRequest::getRequestId();
412  }
413 
421  public static function getURL() {
423  if ( !isset( $wgRequest ) || $wgRequest instanceof FauxRequest ) {
424  return false;
425  }
426  return $wgRequest->getRequestURL();
427  }
428 
436  public static function getLogMessage( $e ) {
437  $id = WebRequest::getRequestId();
438  $type = get_class( $e );
439  $file = $e->getFile();
440  $line = $e->getLine();
441  $message = $e->getMessage();
442  $url = self::getURL() ?: '[no req]';
443 
444  return "[$id] $url $type from line $line of $file: $message";
445  }
446 
451  public static function getPublicLogMessage( $e ) {
452  $reqId = WebRequest::getRequestId();
453  $type = get_class( $e );
454  return '[' . $reqId . '] '
455  . gmdate( 'Y-m-d H:i:s' ) . ': '
456  . 'Fatal exception of type "' . $type . '"';
457  }
458 
469  public static function getLogContext( $e ) {
470  return [
471  'exception' => $e,
472  'exception_id' => WebRequest::getRequestId(),
473  ];
474  }
475 
487  public static function getStructuredExceptionData( $e ) {
488  global $wgLogExceptionBacktrace;
489  $data = [
490  'id' => WebRequest::getRequestId(),
491  'type' => get_class( $e ),
492  'file' => $e->getFile(),
493  'line' => $e->getLine(),
494  'message' => $e->getMessage(),
495  'code' => $e->getCode(),
496  'url' => self::getURL() ?: null,
497  ];
498 
499  if ( $e instanceof ErrorException &&
500  ( error_reporting() & $e->getSeverity() ) === 0
501  ) {
502  // Flag surpressed errors
503  $data['suppressed'] = true;
504  }
505 
506  if ( $wgLogExceptionBacktrace ) {
507  $data['backtrace'] = self::getRedactedTrace( $e );
508  }
509 
510  $previous = $e->getPrevious();
511  if ( $previous !== null ) {
512  $data['previous'] = self::getStructuredExceptionData( $previous );
513  }
514 
515  return $data;
516  }
517 
571  public static function jsonSerializeException( $e, $pretty = false, $escaping = 0 ) {
572  $data = self::getStructuredExceptionData( $e );
573  return FormatJson::encode( $data, $pretty, $escaping );
574  }
575 
585  public static function logException( $e ) {
586  if ( !( $e instanceof MWException ) || $e->isLoggable() ) {
587  $logger = LoggerFactory::getInstance( 'exception' );
588  $logger->error(
589  self::getLogMessage( $e ),
590  self::getLogContext( $e )
591  );
592 
593  $json = self::jsonSerializeException( $e, false, FormatJson::ALL_OK );
594  if ( $json !== false ) {
595  $logger = LoggerFactory::getInstance( 'exception-json' );
596  $logger->error( $json, [ 'private' => true ] );
597  }
598 
599  Hooks::run( 'LogException', [ $e, false ] );
600  }
601  }
602 
610  protected static function logError( ErrorException $e, $channel ) {
611  // The set_error_handler callback is independent from error_reporting.
612  // Filter out unwanted errors manually (e.g. when
613  // MediaWiki\suppressWarnings is active).
614  $suppressed = ( error_reporting() & $e->getSeverity() ) === 0;
615  if ( !$suppressed ) {
616  $logger = LoggerFactory::getInstance( $channel );
617  $logger->error(
618  self::getLogMessage( $e ),
619  self::getLogContext( $e )
620  );
621  }
622 
623  // Include all errors in the json log (surpressed errors will be flagged)
624  $json = self::jsonSerializeException( $e, false, FormatJson::ALL_OK );
625  if ( $json !== false ) {
626  $logger = LoggerFactory::getInstance( "{$channel}-json" );
627  $logger->error( $json, [ 'private' => true ] );
628  }
629 
630  Hooks::run( 'LogException', [ $e, $suppressed ] );
631  }
632 }
static getStructuredExceptionData($e)
Get a structured representation of an Exception.
static handleFatalError($level=null, $message=null, $file=null, $line=null, $context=null, $trace=null)
Dual purpose callback used as both a set_error_handler() callback and a registered shutdown function...
Database error base class.
Definition: DBError.php:26
the array() calling protocol came about after MediaWiki 1.4rc1.
static getRequestId()
Get the unique request ID.
Definition: WebRequest.php:272
static getLogMessage($e)
Get a message formatting the exception message and its origin.
$context
Definition: load.php:50
Apache License January AND DISTRIBUTION Definitions License shall mean the terms and conditions for use
if(!$wgDBerrorLogTZ) $wgRequest
Definition: Setup.php:664
div flags Integer display flags(NO_ACTION_LINK, NO_EXTRA_USER_LINKS) 'LogException'returning false will NOT prevent logging $e
Definition: hooks.txt:2102
static handleError($level, $message, $file=null, $line=null)
Handler for set_error_handler() callback notifications.
const ALL_OK
Skip escaping as many characters as reasonably possible.
Definition: FormatJson.php:55
injection txt This is an overview of how MediaWiki makes use of dependency injection The design described here grew from the discussion of RFC T384 The term dependency this means that anything an object needs to operate should be injected from the the object itself should only know narrow no concrete implementation of the logic it relies on The requirement to inject everything typically results in an architecture that based on two main types of and essentially stateless service objects that use other service objects to operate on the value objects As of the beginning MediaWiki is only starting to use the DI approach Much of the code still relies on global state or direct resulting in a highly cyclical dependency MediaWikiServices
Definition: injection.txt:23
static handleException($e)
Exception handler which simulates the appropriate catch() handling:
A helper class for throttling authentication attempts.
when a variable name is used in a it is silently declared as a new local masking the global
Definition: design.txt:93
wfRandomString($length=32)
Get a random string containing a number of pseudo-random hex characters.
static logError(ErrorException $e, $channel)
Log an exception that wasn't thrown but made to wrap an error.
static encode($value, $pretty=false, $escaping=0)
Returns the JSON representation of a value.
Definition: FormatJson.php:127
static getURL()
If the exception occurred in the course of responding to a request, returns the requested URL...
wfDeprecated($function, $version=false, $component=false, $callerOffset=2)
Throws a warning that $function is deprecated.
static output($e, $mode, $eNew=null)
static run($event, array $args=[], $deprecatedVersion=null)
Call hook functions defined in Hooks::register and $wgHooks.
Definition: Hooks.php:131
static redactTrace(array $trace)
Redact a stacktrace generated by Exception::getTrace(), debug_backtrace() or similar means...
static configuration should be added through ResourceLoaderGetConfigVars instead can be used to get the real title after the basic globals have been set but before ordinary actions take place or wrap services the preferred way to define a new service is the $wgServiceWiringFiles array $services
Definition: hooks.txt:2159
static getRedactedTraceAsString($e)
Generate a string representation of an exception's stack trace.
This document is intended to provide useful advice for parties seeking to redistribute MediaWiki to end users It s targeted particularly at maintainers for Linux since it s been observed that distribution packages of MediaWiki often break We ve consistently had to recommend that users seeking support use official tarballs instead of their distribution s and this often solves whatever problem the user is having It would be nice if this could such as
Definition: distributors.txt:9
static rollbackMasterChangesAndLog($e)
If there are any open database transactions, roll them back and log the stack trace of the exception ...
injection txt This is an overview of how MediaWiki makes use of dependency injection The design described here grew from the discussion of RFC T384 The term dependency this means that anything an object needs to operate should be injected from the the object itself should only know narrow no concrete implementation of the logic it relies on The requirement to inject everything typically results in an architecture that based on two main types of and essentially stateless service objects that use other service objects to operate on the value objects As of the beginning MediaWiki is only starting to use the DI approach Much of the code still relies on global state or direct resulting in a highly cyclical dependency which acts as the top level factory for services in MediaWiki which can be used to gain access to default instances of various services MediaWikiServices however also allows new services to be defined and default services to be redefined Services are defined or redefined by providing a callback the instantiator that will return a new instance of the service When it will create an instance of MediaWikiServices and populate it with the services defined in the files listed by thereby bootstrapping the DI framework Per $wgServiceWiringFiles lists includes ServiceWiring php
Definition: injection.txt:35
$lbFactory
static installHandler()
Install handlers with PHP.
static getLogContext($e)
Get a PSR-3 log event context from an Exception.
$line
Definition: cdb.php:59
MediaWiki Logger LoggerFactory implements a PSR[0] compatible message logging system Named Psr Log LoggerInterface instances can be obtained from the MediaWiki Logger LoggerFactory::getInstance() static method.MediaWiki\Logger\LoggerFactory expects a class implementing the MediaWiki\Logger\Spi interface to act as a factory for new Psr\Log\LoggerInterface instances.The"Spi"in MediaWiki\Logger\Spi stands for"service provider interface".An SPI is an API intended to be implemented or extended by a third party.This software design pattern is intended to enable framework extension and replaceable components.It is specifically used in the MediaWiki\Logger\LoggerFactory service to allow alternate PSR-3 logging implementations to be easily integrated with MediaWiki.The service provider interface allows the backend logging library to be implemented in multiple ways.The $wgMWLoggerDefaultSpi global provides the classname of the default MediaWiki\Logger\Spi implementation to be loaded at runtime.This can either be the name of a class implementing the MediaWiki\Logger\Spi with a zero argument const ructor or a callable that will return an MediaWiki\Logger\Spi instance.Alternately the MediaWiki\Logger\LoggerFactory MediaWiki Logger LoggerFactory
Definition: logger.txt:5
We ve cleaned up the code here by removing clumps of infrequently used code and moving them off somewhere else It s much easier for someone working with this code to see what s _really_ going on
Definition: hooks.txt:86
static jsonSerializeException($e, $pretty=false, $escaping=0)
Serialize an Exception object to JSON.
static getRedactedTrace($e)
Return a copy of an exception's backtrace as an array.
static prettyPrintTrace(array $trace, $pad= '')
Generate a string representation of a stacktrace.
div flags Integer display flags(NO_ACTION_LINK, NO_EXTRA_USER_LINKS) 'LogException'returning false will NOT prevent logging a wrapping ErrorException $suppressed
Definition: hooks.txt:2102
static logException($e)
Log an exception to the exception log (if enabled).
static report($e)
Report an exception to the user.
static getLogId($e)
Get the ID for this exception.
do that in ParserLimitReportFormat instead use this to modify the parameters of the image and a DIV can begin in one section and end in another Make sure your code can handle that case gracefully See the EditSectionClearerLink extension for an example zero but section is usually empty its values are the globals values before the output is cached one of or reset my talk my contributions etc etc otherwise the built in rate limiting checks are if enabled allows for interception of redirect as a string mapping parameter names to values & $type
Definition: hooks.txt:2491