Current File : //data/www_bck/varak.net_bck/havranipapuce.varak.net/includes/exception/MWExceptionHandler.php
<?php
/**
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
* http://www.gnu.org/copyleft/gpl.html
*
* @file
*/
/**
* Handler class for MWExceptions
* @ingroup Exception
*/
class MWExceptionHandler {
protected static $reservedMemory;
protected static $fatalErrorTypes = array(
E_ERROR, E_PARSE, E_CORE_ERROR, E_COMPILE_ERROR, E_USER_ERROR,
/* HHVM's FATAL_ERROR level */ 16777217,
);
/**
* Install handlers with PHP.
*/
public static function installHandler() {
set_exception_handler( array( 'MWExceptionHandler', 'handleException' ) );
set_error_handler( array( 'MWExceptionHandler', 'handleError' ) );
// Reserve 16k of memory so we can report OOM fatals
self::$reservedMemory = str_repeat( ' ', 16384 );
register_shutdown_function(
array( 'MWExceptionHandler', 'handleFatalError' )
);
}
/**
* Report an exception to the user
* @param Exception $e
*/
protected static function report( Exception $e ) {
global $wgShowExceptionDetails;
$cmdLine = MWException::isCommandLine();
if ( $e instanceof MWException ) {
try {
// Try and show the exception prettily, with the normal skin infrastructure
$e->report();
} catch ( Exception $e2 ) {
// Exception occurred from within exception handler
// Show a simpler message for the original exception,
// don't try to invoke report()
$message = "MediaWiki internal error.\n\n";
if ( $wgShowExceptionDetails ) {
$message .= 'Original exception: ' . self::getLogMessage( $e ) .
"\nBacktrace:\n" . self::getRedactedTraceAsString( $e ) .
"\n\nException caught inside exception handler: " . self::getLogMessage( $e2 ) .
"\nBacktrace:\n" . self::getRedactedTraceAsString( $e2 );
} else {
$message .= "Exception caught inside exception handler.\n\n" .
"Set \$wgShowExceptionDetails = true; at the bottom of LocalSettings.php " .
"to show detailed debugging information.";
}
$message .= "\n";
if ( $cmdLine ) {
self::printError( $message );
} else {
echo nl2br( htmlspecialchars( $message ) ) . "\n";
}
}
} else {
$message = "Exception encountered, of type \"" . get_class( $e ) . "\"";
if ( $wgShowExceptionDetails ) {
$message .= "\n" . MWExceptionHandler::getLogMessage( $e ) . "\nBacktrace:\n" .
self::getRedactedTraceAsString( $e ) . "\n";
}
if ( $cmdLine ) {
self::printError( $message );
} else {
echo nl2br( htmlspecialchars( $message ) ) . "\n";
}
}
}
/**
* Print a message, if possible to STDERR.
* Use this in command line mode only (see isCommandLine)
*
* @param string $message Failure text
*/
public static function printError( $message ) {
# NOTE: STDERR may not be available, especially if php-cgi is used from the
# command line (bug #15602). Try to produce meaningful output anyway. Using
# echo may corrupt output to STDOUT though.
if ( defined( 'STDERR' ) ) {
fwrite( STDERR, $message );
} else {
echo $message;
}
}
/**
* 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
*/
public static function rollbackMasterChangesAndLog( Exception $e ) {
$factory = wfGetLBFactory();
if ( $factory->hasMasterChanges() ) {
wfDebugLog( 'Bug56269',
'Exception thrown with an uncommited database transaction: ' .
MWExceptionHandler::getLogMessage( $e ) . "\n" .
$e->getTraceAsString()
);
$factory->rollbackMasterChanges();
}
}
/**
* Exception handler which simulates the appropriate catch() handling:
*
* try {
* ...
* } catch ( Exception $e ) {
* $e->report();
* } catch ( Exception $e ) {
* echo $e->__toString();
* }
*
* @since 1.25
* @param Exception $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 );
// 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
* argument type or class name.
*
* @param Exception $e
* @return string
*/
public static function getRedactedTraceAsString( Exception $e ) {
$text = '';
foreach ( self::getRedactedTrace( $e ) as $level => $frame ) {
if ( isset( $frame['file'] ) && isset( $frame['line'] ) ) {
$text .= "#{$level} {$frame['file']}({$frame['line']}): ";
} else {
// 'file' and 'line' are unset for calls via call_user_func (bug 55634)
// This matches behaviour of Exception::getTraceAsString to instead
// display "[internal function]".
$text .= "#{$level} [internal function]: ";
}
if ( isset( $frame['class'] ) ) {
$text .= $frame['class'] . $frame['type'] . $frame['function'];
} else {
$text .= $frame['function'];
}
if ( isset( $frame['args'] ) ) {
$text .= '(' . implode( ', ', $frame['args'] ) . ")\n";
} else {
$text .= "()\n";
}
}
$level = $level + 1;
$text .= "#{$level} {main}";
return $text;
}
/**
* Return a copy of an exception's backtrace as an array.
*
* Like Exception::getTrace, but replaces each element in each frame's
* argument array with the name of its class (if the element is an object)
* or its type (if the element is a PHP primitive).
*
* @since 1.22
* @param Exception $e
* @return array
*/
public static function getRedactedTrace( Exception $e ) {
return array_map( function ( $frame ) {
if ( isset( $frame['args'] ) ) {
$frame['args'] = array_map( function ( $arg ) {
return is_object( $arg ) ? get_class( $arg ) : gettype( $arg );
}, $frame['args'] );
}
return $frame;
}, $e->getTrace() );
}
/**
* 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.
*
* @since 1.22
* @param Exception $e
* @return string
*/
public static function getLogId( Exception $e ) {
if ( !isset( $e->_mwLogId ) ) {
$e->_mwLogId = wfRandomString( 8 );
}
return $e->_mwLogId;
}
/**
* If the exception occurred in the course of responding to a request,
* returns the requested URL. Otherwise, returns false.
*
* @since 1.23
* @return string|false
*/
public static function getURL() {
global $wgRequest;
if ( !isset( $wgRequest ) || $wgRequest instanceof FauxRequest ) {
return false;
}
return $wgRequest->getRequestURL();
}
/**
* Get a message formatting the exception message and its origin.
*
* @since 1.22
* @param Exception $e
* @return string
*/
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 $type from line $line of $file: $message";
}
/**
* Serialize an Exception object to JSON.
*
* The JSON object will have keys 'id', 'file', 'line', 'message', and
* 'url'. These keys map to string values, with the exception of 'line',
* which is a number, and 'url', which may be either a string URL or or
* null if the exception did not occur in the context of serving a web
* request.
*
* If $wgLogExceptionBacktrace is true, it will also have a 'backtrace'
* key, mapped to the array return value of Exception::getTrace, but with
* each element in each frame's "args" array (if set) replaced with the
* argument's class name (if the argument is an object) or type name (if
* the argument is a PHP primitive).
*
* @par Sample JSON record ($wgLogExceptionBacktrace = false):
* @code
* {
* "id": "c41fb419",
* "type": "MWException",
* "file": "/var/www/mediawiki/includes/cache/MessageCache.php",
* "line": 704,
* "message": "Non-string key given",
* "url": "/wiki/Main_Page"
* }
* @endcode
*
* @par Sample JSON record ($wgLogExceptionBacktrace = true):
* @code
* {
* "id": "dc457938",
* "type": "MWException",
* "file": "/vagrant/mediawiki/includes/cache/MessageCache.php",
* "line": 704,
* "message": "Non-string key given",
* "url": "/wiki/Main_Page",
* "backtrace": [{
* "file": "/vagrant/mediawiki/extensions/VisualEditor/VisualEditor.hooks.php",
* "line": 80,
* "function": "get",
* "class": "MessageCache",
* "type": "->",
* "args": ["array"]
* }]
* }
* @endcode
*
* @since 1.23
* @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|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
// fact visible and explicit.
$exceptionData['url'] = self::getURL() ?: null;
if ( $wgLogExceptionBacktrace ) {
// Argument values may not be serializable, so redact them.
$exceptionData['backtrace'] = self::getRedactedTrace( $e );
}
return FormatJson::encode( $exceptionData, $pretty, $escaping );
}
/**
* 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 exceptions or exceptions from other libraries.
*
* @since 1.22
* @param Exception $e
*/
public static function logException( Exception $e ) {
global $wgLogExceptionBacktrace;
if ( !( $e instanceof MWException ) || $e->isLoggable() ) {
$log = self::getLogMessage( $e );
if ( $wgLogExceptionBacktrace ) {
wfDebugLog( 'exception', $log . "\n" . $e->getTraceAsString() );
} else {
wfDebugLog( 'exception', $log );
}
$json = self::jsonSerializeException( $e, false, FormatJson::ALL_OK );
if ( $json !== false ) {
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' );
}
}
}
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