diff options
Diffstat (limited to 'includes/exception/MWExceptionHandler.php')
| -rw-r--r-- | includes/exception/MWExceptionHandler.php | 201 |
1 files changed, 174 insertions, 27 deletions
diff --git a/includes/exception/MWExceptionHandler.php b/includes/exception/MWExceptionHandler.php index 71917e13..c50b6c8c 100644 --- a/includes/exception/MWExceptionHandler.php +++ b/includes/exception/MWExceptionHandler.php @@ -23,11 +23,25 @@ * @ingroup Exception */ class MWExceptionHandler { + + protected static $reservedMemory; + protected static $fatalErrorTypes = array( + E_ERROR, E_PARSE, E_CORE_ERROR, E_COMPILE_ERROR, E_USER_ERROR, + /* HHVM's FATAL_ERROR level */ 16777217, + ); + /** - * Install an exception handler for MediaWiki exception types. + * Install handlers with PHP. */ public static function installHandler() { - set_exception_handler( array( 'MWExceptionHandler', 'handle' ) ); + set_exception_handler( array( 'MWExceptionHandler', 'handleException' ) ); + set_error_handler( array( 'MWExceptionHandler', 'handleError' ) ); + + // Reserve 16k of memory so we can report OOM fatals + self::$reservedMemory = str_repeat( ' ', 16384 ); + register_shutdown_function( + array( 'MWExceptionHandler', 'handleFatalError' ) + ); } /** @@ -45,7 +59,7 @@ class MWExceptionHandler { $e->report(); } catch ( Exception $e2 ) { // Exception occurred from within exception handler - // Show a simpler error message for the original exception, + // Show a simpler message for the original exception, // don't try to invoke report() $message = "MediaWiki internal error.\n\n"; @@ -69,8 +83,7 @@ class MWExceptionHandler { } } } else { - $message = "Unexpected non-MediaWiki exception encountered, of type \"" . - get_class( $e ) . "\""; + $message = "Exception encountered, of type \"" . get_class( $e ) . "\""; if ( $wgShowExceptionDetails ) { $message .= "\n" . MWExceptionHandler::getLogMessage( $e ) . "\nBacktrace:\n" . @@ -82,6 +95,7 @@ class MWExceptionHandler { } else { echo nl2br( htmlspecialchars( $message ) ) . "\n"; } + } } @@ -106,6 +120,7 @@ class MWExceptionHandler { * If there are any open database transactions, roll them back and log * the stack trace of the exception that should have been caught so the * transaction could be aborted properly. + * * @since 1.23 * @param Exception $e */ @@ -126,34 +141,132 @@ class MWExceptionHandler { * * try { * ... - * } catch ( MWException $e ) { + * } catch ( Exception $e ) { * $e->report(); * } catch ( Exception $e ) { * echo $e->__toString(); * } + * + * @since 1.25 * @param Exception $e */ - public static function handle( $e ) { - global $wgFullyInitialised; - - self::rollbackMasterChangesAndLog( $e ); + public static function handleException( Exception $e ) { + try { + // Rollback DBs to avoid transaction notices. This may fail + // to rollback some DB due to connection issues or exceptions. + // However, any sane DB driver will rollback implicitly anyway. + self::rollbackMasterChangesAndLog( $e ); + } catch ( DBError $e2 ) { + // If the DB is unreacheable, rollback() will throw an error + // and the error report() method might need messages from the DB, + // which would result in an exception loop. PHP may escalate such + // errors to "Exception thrown without a stack frame" fatals, but + // it's better to be explicit here. + self::logException( $e2 ); + } + self::logException( $e ); self::report( $e ); - // Final cleanup - if ( $wgFullyInitialised ) { - try { - // uses $wgRequest, hence the $wgFullyInitialised condition - wfLogProfilingData(); - } catch ( Exception $e ) { - } - } - // Exit value should be nonzero for the benefit of shell jobs exit( 1 ); } /** + * @since 1.25 + * @param int $level Error level raised + * @param string $message + * @param string $file + * @param int $line + */ + public static function handleError( $level, $message, $file = null, $line = null ) { + // Map error constant to error name (reverse-engineer PHP error reporting) + $channel = 'error'; + switch ( $level ) { + case E_ERROR: + case E_CORE_ERROR: + case E_COMPILE_ERROR: + case E_USER_ERROR: + case E_RECOVERABLE_ERROR: + case E_PARSE: + $levelName = 'Error'; + $channel = 'fatal'; + break; + case E_WARNING: + case E_CORE_WARNING: + case E_COMPILE_WARNING: + case E_USER_WARNING: + $levelName = 'Warning'; + break; + case E_NOTICE: + case E_USER_NOTICE: + $levelName = 'Notice'; + break; + case E_STRICT: + $levelName = 'Strict Standards'; + break; + case E_DEPRECATED: + case E_USER_DEPRECATED: + $levelName = 'Deprecated'; + break; + case /* HHVM's FATAL_ERROR */ 16777217: + $levelName = 'Fatal'; + $channel = 'fatal'; + break; + default: + $levelName = 'Unknown error'; + break; + } + + $e = new ErrorException( "PHP $levelName: $message", 0, $level, $file, $line ); + self::logError( $e, $channel ); + + // This handler is for logging only. Return false will instruct PHP + // to continue regular handling. + return false; + } + + + /** + * Look for a fatal error as the cause of the request termination and log + * as an exception. + * + * Special handling is included for missing class errors as they may + * indicate that the user needs to install 3rd-party libraries via + * Composer or other means. + * + * @since 1.25 + */ + public static function handleFatalError() { + self::$reservedMemory = null; + $lastError = error_get_last(); + + if ( $lastError && + isset( $lastError['type'] ) && + in_array( $lastError['type'], self::$fatalErrorTypes ) + ) { + $msg = "Fatal Error: {$lastError['message']}"; + // HHVM: Class undefined: foo + // PHP5: Class 'foo' not found + if ( preg_match( "/Class (undefined: \w+|'\w+' not found)/", + $lastError['message'] + ) ) { + // @codingStandardsIgnoreStart Generic.Files.LineLength.TooLong + $msg = <<<TXT +{$msg} + +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. + +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. +TXT; + // @codingStandardsIgnoreEnd + } + $e = new ErrorException( $msg, 0, $lastError['type'] ); + self::logError( $e, 'fatal' ); + } + } + + /** * Generate a string representation of an exception's stack trace * * Like Exception::getTraceAsString, but replaces argument values with @@ -217,7 +330,7 @@ class MWExceptionHandler { } /** - * Get the ID for this error. + * Get the ID for this exception. * * The ID is saved so that one can match the one output to the user (when * $wgShowExceptionDetails is set to false), to the entry in the debug log. @@ -238,7 +351,7 @@ class MWExceptionHandler { * returns the requested URL. Otherwise, returns false. * * @since 1.23 - * @return string|bool + * @return string|false */ public static function getURL() { global $wgRequest; @@ -249,8 +362,7 @@ class MWExceptionHandler { } /** - * Return the requested URL and point to file and line number from which the - * exception occurred. + * Get a message formatting the exception message and its origin. * * @since 1.22 * @param Exception $e @@ -258,12 +370,13 @@ class MWExceptionHandler { */ public static function getLogMessage( Exception $e ) { $id = self::getLogId( $e ); + $type = get_class( $e ); $file = $e->getFile(); $line = $e->getLine(); $message = $e->getMessage(); $url = self::getURL() ?: '[no req]'; - return "[$id] $url Exception from line $line of $file: $message"; + return "[$id] $url $type from line $line of $file: $message"; } /** @@ -285,6 +398,7 @@ class MWExceptionHandler { * @code * { * "id": "c41fb419", + * "type": "MWException", * "file": "/var/www/mediawiki/includes/cache/MessageCache.php", * "line": 704, * "message": "Non-string key given", @@ -296,6 +410,7 @@ class MWExceptionHandler { * @code * { * "id": "dc457938", + * "type": "MWException", * "file": "/vagrant/mediawiki/includes/cache/MessageCache.php", * "line": 704, * "message": "Non-string key given", @@ -315,18 +430,24 @@ class MWExceptionHandler { * @param Exception $e * @param bool $pretty Add non-significant whitespace to improve readability (default: false). * @param int $escaping Bitfield consisting of FormatJson::.*_OK class constants. - * @return string|bool JSON string if successful; false upon failure + * @return string|false JSON string if successful; false upon failure */ public static function jsonSerializeException( Exception $e, $pretty = false, $escaping = 0 ) { global $wgLogExceptionBacktrace; $exceptionData = array( 'id' => self::getLogId( $e ), + 'type' => get_class( $e ), 'file' => $e->getFile(), 'line' => $e->getLine(), 'message' => $e->getMessage(), ); + if ( $e instanceof ErrorException && ( error_reporting() & $e->getSeverity() ) === 0 ) { + // Flag surpressed errors + $exceptionData['suppressed'] = true; + } + // Because MediaWiki is first and foremost a web application, we set a // 'url' key unconditionally, but set it to null if the exception does // not occur in the context of a web request, as a way of making that @@ -345,7 +466,7 @@ class MWExceptionHandler { * Log an exception to the exception log (if enabled). * * This method must not assume the exception is an MWException, - * it is also used to handle PHP errors or errors from other libraries. + * it is also used to handle PHP exceptions or exceptions from other libraries. * * @since 1.22 * @param Exception $e @@ -366,7 +487,33 @@ class MWExceptionHandler { wfDebugLog( 'exception-json', $json, 'private' ); } } - } + /** + * Log an exception that wasn't thrown but made to wrap an error. + * + * @since 1.25 + * @param ErrorException $e + * @param string $channel + */ + protected static function logError( ErrorException $e, $channel ) { + global $wgLogExceptionBacktrace; + + // The set_error_handler callback is independent from error_reporting. + // Filter out unwanted errors manually (e.g. when wfSuppressWarnings is active). + if ( ( error_reporting() & $e->getSeverity() ) !== 0 ) { + $log = self::getLogMessage( $e ); + if ( $wgLogExceptionBacktrace ) { + wfDebugLog( $channel, $log . "\n" . $e->getTraceAsString() ); + } else { + wfDebugLog( $channel, $log ); + } + } + + // Include all errors in the json log (surpressed errors will be flagged) + $json = self::jsonSerializeException( $e, false, FormatJson::ALL_OK ); + if ( $json !== false ) { + wfDebugLog( "$channel-json", $json, 'private' ); + } + } } |