mediawiki-extensions-Scribunto/engines/LuaStandalone/LuaStandaloneEngine.php
Tim Starling e7f5aae520 Fix race condition in SIGXCPU handling
Marius found a race condition in the handling of SIGXCPU: the pipes
would close, causing the read/write to complete, before the status of
the process changed, so the status would randomly be "running" for a few
milliseconds after proc_get_status() was called.

So: terminate the process unconditionally after an I/O error. Get the
exit status from proc_close(), since that's the only way to get the
status of a terminated process while simultaneously waiting for it to
exit. Also fix signal identification as in unmerged patch I57cdf8aa.

Change-Id: I252ec046e82063a868c1094e81705cb5e847db92
2015-05-25 16:40:31 +00:00

727 lines
19 KiB
PHP

<?php
class Scribunto_LuaStandaloneEngine extends Scribunto_LuaEngine {
static $clockTick;
public $initialStatus;
public function load() {
parent::load();
if ( php_uname( 's' ) === 'Linux' ) {
$this->initialStatus = $this->interpreter->getStatus();
} else {
$this->initialStatus = false;
}
}
public function getPerformanceCharacteristics() {
return array(
'phpCallsRequireSerialization' => true,
);
}
/**
* @return string
*/
function getLimitReport() {
try {
$this->load();
} catch ( Exception $e ) {
return '';
}
if ( !$this->initialStatus ) {
return '';
}
$status = $this->interpreter->getStatus();
$lang = Language::factory( 'en' );
return
'Lua time usage: ' . sprintf( "%.3f", $status['time'] / $this->getClockTick() ) . "s\n" .
'Lua virtual size: ' .
$lang->formatSize( $status['vsize'] ) . ' / ' .
$lang->formatSize( $this->options['memoryLimit'] ) . "\n" .
'Lua estimated memory usage: ' .
$lang->formatSize( $status['vsize'] - $this->initialStatus['vsize'] ) . "\n";
}
function reportLimitData( ParserOutput $output ) {
try {
$this->load();
} catch ( Exception $e ) {
return;
}
if ( $this->initialStatus ) {
$status = $this->interpreter->getStatus();
$output->setLimitReportData( 'scribunto-limitreport-timeusage',
array(
sprintf( "%.3f", $status['time'] / $this->getClockTick() ),
sprintf( "%.3f", $this->options['cpuLimit'] )
)
);
$output->setLimitReportData( 'scribunto-limitreport-virtmemusage',
array(
$status['vsize'],
$this->options['memoryLimit']
)
);
$output->setLimitReportData( 'scribunto-limitreport-estmemusage',
$status['vsize'] - $this->initialStatus['vsize']
);
}
$logs = $this->getLogBuffer();
if ( $logs !== '' ) {
$output->addModules( 'ext.scribunto.logs' );
$output->setLimitReportData( 'scribunto-limitreport-logs', $logs );
}
}
function formatLimitData( $key, &$value, &$report, $isHTML, $localize ) {
global $wgLang;
$lang = $localize ? $wgLang : Language::factory( 'en' );
switch ( $key ) {
case 'scribunto-limitreport-logs':
if ( $isHTML ) {
$report .= $this->formatHtmlLogs( $value, $localize );
}
return false;
case 'scribunto-limitreport-virtmemusage':
$value = array_map( array( $lang, 'formatSize' ), $value );
break;
case 'scribunto-limitreport-estmemusage':
$value = $lang->formatSize( $value );
break;
}
return true;
}
/**
* @return mixed
*/
function getClockTick() {
if ( self::$clockTick === null ) {
wfSuppressWarnings();
self::$clockTick = intval( shell_exec( 'getconf CLK_TCK' ) );
wfRestoreWarnings();
if ( !self::$clockTick ) {
self::$clockTick = 100;
}
}
return self::$clockTick;
}
/**
* @return Scribunto_LuaStandaloneInterpreter
*/
function newInterpreter() {
return new Scribunto_LuaStandaloneInterpreter( $this, $this->options );
}
public function getSoftwareInfo( array &$software ) {
$ver = Scribunto_LuaStandaloneInterpreter::getLuaVersion( $this->options );
if ( $ver !== null ) {
if ( substr( $ver, 0, 6 ) === 'LuaJIT' ) {
$software['[http://luajit.org/ LuaJIT]'] = str_replace( 'LuaJIT ', '', $ver );
} else {
$software['[http://www.lua.org/ Lua]'] = str_replace( 'Lua ', '', $ver );
}
}
}
}
class Scribunto_LuaStandaloneInterpreter extends Scribunto_LuaInterpreter {
static $nextInterpreterId = 0;
/**
* @var Scribunto_LuaStandaloneEngine
*/
public $engine;
/**
* @var bool
*/
public $enableDebug;
/**
* @var resource
*/
public $proc;
/**
* @var resource
*/
public $writePipe;
/**
* @var resource
*/
public $readPipe;
/**
* @var ScribuntoException
*/
public $exitError;
/**
* @var int
*/
public $id;
/**
* @param Scribunto_LuaStandaloneEngine $engine
* @param array $options
* @throws MWException
* @throws Scribunto_LuaInterpreterNotFoundError
* @throws ScribuntoException
*/
function __construct( $engine, array $options ) {
$this->id = self::$nextInterpreterId++;
if ( $options['errorFile'] === null ) {
$options['errorFile'] = wfGetNull();
}
if ( $options['luaPath'] === null ) {
$path = false;
// Note, if you alter these, also alter getLuaVersion() below
if ( PHP_OS == 'Linux' ) {
if ( PHP_INT_SIZE == 4 ) {
$path = 'lua5_1_5_linux_32_generic/lua';
} elseif ( PHP_INT_SIZE == 8 ) {
$path = 'lua5_1_5_linux_64_generic/lua';
}
} elseif ( PHP_OS == 'Windows' || PHP_OS == 'WINNT' || PHP_OS == 'Win32' ) {
if ( PHP_INT_SIZE == 4 ) {
$path = 'lua5_1_4_Win32_bin/lua5.1.exe';
} elseif ( PHP_INT_SIZE == 8 ) {
$path = 'lua5_1_4_Win64_bin/lua5.1.exe';
}
} elseif ( PHP_OS == 'Darwin' ) {
$path = 'lua5_1_5_mac_lion_fat_generic/lua';
}
if ( $path === false ) {
throw new Scribunto_LuaInterpreterNotFoundError(
'No Lua interpreter was given in the configuration, ' .
'and no bundled binary exists for this platform.' );
}
$options['luaPath'] = dirname( __FILE__ ) . "/binaries/$path";
if( !is_executable( $options['luaPath'] ) ) {
throw new MWException( sprintf( 'The lua binary (%s) is not executable.', $options['luaPath'] ) );
}
}
$this->engine = $engine;
$this->enableDebug = !empty( $options['debug'] );
$pipes = null;
$cmd = wfEscapeShellArg(
$options['luaPath'],
dirname( __FILE__ ) . '/mw_main.lua',
dirname( dirname( dirname( __FILE__ ) ) ),
$this->id
);
if ( php_uname( 's' ) == 'Linux' ) {
// Limit memory and CPU
$cmd = wfEscapeShellArg(
'/bin/sh',
dirname( __FILE__ ) . '/lua_ulimit.sh',
$options['cpuLimit'], # soft limit (SIGXCPU)
$options['cpuLimit'] + 1, # hard limit
intval( $options['memoryLimit'] / 1024 ),
$cmd );
}
if ( php_uname( 's' ) == 'Windows NT' ) {
// Like the passthru() in older versions of PHP,
// PHP's invokation of cmd.exe in proc_open() is broken:
// http://news.php.net/php.internals/21796
// Unlike passthru(), it is not fixed in any PHP version,
// so we use the fix similar to one in wfShellExec()
$cmd = '"' . $cmd . '"';
}
wfDebug( __METHOD__.": creating interpreter: $cmd\n" );
// Check whether proc_open is available before trying to call it (e.g.
// PHP's disable_functions may have removed it)
if ( !function_exists( 'proc_open' ) ) {
throw $this->engine->newException( 'scribunto-luastandalone-proc-error-proc-open' );
}
// Clear the "last error", so if proc_open fails we can know any
// warning was generated by that.
@trigger_error( '' );
$this->proc = proc_open(
$cmd,
array(
array( 'pipe', 'r' ),
array( 'pipe', 'w' ),
array( 'file', $options['errorFile'], 'a' )
),
$pipes );
if ( !$this->proc ) {
$err = error_get_last();
if ( !empty( $err['message'] ) ) {
throw $this->engine->newException( 'scribunto-luastandalone-proc-error-msg',
array( 'args' => array( $err['message'] ) ) );
} elseif ( wfIniGetBool( 'safe_mode' ) ) {
/** @todo: Remove this case once we no longer support PHP 5.3 */
throw $this->engine->newException( 'scribunto-luastandalone-proc-error-safe-mode' );
} else {
throw $this->engine->newException( 'scribunto-luastandalone-proc-error' );
}
}
$this->writePipe = $pipes[0];
$this->readPipe = $pipes[1];
}
function __destruct() {
$this->terminate();
}
public static function getLuaVersion( array $options ) {
if ( $options['luaPath'] === null ) {
// We know which versions are distributed, no need to run them.
if ( PHP_OS == 'Linux' ) {
return 'Lua 5.1.5';
} elseif ( PHP_OS == 'Windows' || PHP_OS == 'WINNT' || PHP_OS == 'Win32' ) {
return 'Lua 5.1.4';
} elseif ( PHP_OS == 'Darwin' ) {
return 'Lua 5.1.5';
} else {
return null;
}
}
// Ask the interpreter what version it is, using the "-v" option.
// The output is expected to be one line, something like these:
// Lua 5.1.5 Copyright (C) 1994-2012 Lua.org, PUC-Rio
// LuaJIT 2.0.0 -- Copyright (C) 2005-2012 Mike Pall. http://luajit.org/
$cmd = wfEscapeShellArg( $options['luaPath'] ) . ' -v';
$handle = popen( $cmd, 'r' );
if ( $handle ) {
$ret = fgets( $handle, 80 );
pclose( $handle );
if( $ret && preg_match( '/^Lua(?:JIT)? \S+/', $ret, $m ) ) {
return $m[0];
}
}
return null;
}
public function terminate() {
if ( $this->proc ) {
wfDebug( __METHOD__.": terminating\n" );
proc_terminate( $this->proc );
proc_close( $this->proc );
$this->proc = false;
}
}
public function quit() {
if ( !$this->proc ) {
return;
}
$this->dispatch( array( 'op' => 'quit' ) );
proc_close( $this->proc );
}
/**
* @param string $text
* @param string $chunkName
* @return Scribunto_LuaStandaloneInterpreterFunction
*/
public function loadString( $text, $chunkName ) {
$this->cleanupLuaChunks();
$result = $this->dispatch( array(
'op' => 'loadString',
'text' => $text,
'chunkName' => $chunkName
) );
return new Scribunto_LuaStandaloneInterpreterFunction( $this->id, $result[1] );
}
public function callFunction( $func /* ... */ ) {
if ( !($func instanceof Scribunto_LuaStandaloneInterpreterFunction) ) {
throw new MWException( __METHOD__.': invalid function type' );
}
if ( $func->interpreterId !== $this->id ) {
throw new MWException( __METHOD__.': function belongs to a different interpreter' );
}
$args = func_get_args();
unset( $args[0] );
// $args is now conveniently a 1-based array, as required by the Lua server
$this->cleanupLuaChunks();
$result = $this->dispatch( array(
'op' => 'call',
'id' => $func->id,
'nargs' => count( $args ),
'args' => $args ) );
// Convert return values to zero-based
return array_values( $result );
}
public function wrapPhpFunction( $callable ) {
static $uid = 0;
$id = "anonymous*" . ++$uid;
$this->callbacks[$id] = $callable;
$ret = $this->dispatch( array(
'op' => 'wrapPhpFunction',
'id' => $id ) );
return $ret[1];
}
public function cleanupLuaChunks() {
if ( isset( Scribunto_LuaStandaloneInterpreterFunction::$anyChunksDestroyed[$this->id] ) ) {
unset( Scribunto_LuaStandaloneInterpreterFunction::$anyChunksDestroyed[$this->id] );
$this->dispatch( array(
'op' => 'cleanupChunks',
'ids' => Scribunto_LuaStandaloneInterpreterFunction::$activeChunkIds[$this->id]
) );
}
}
public function isLuaFunction( $object ) {
return $object instanceof Scribunto_LuaStandaloneInterpreterFunction;
}
public function registerLibrary( $name, array $functions ) {
$functionIds = array();
foreach ( $functions as $funcName => $callback ) {
$id = "$name-$funcName";
$this->callbacks[$id] = $callback;
$functionIds[$funcName] = $id;
}
$this->dispatch( array(
'op' => 'registerLibrary',
'name' => $name,
'functions' => $functionIds ) );
}
public function getStatus() {
$result = $this->dispatch( array(
'op' => 'getStatus' ) );
return $result[1];
}
public function pauseUsageTimer() {
}
public function unpauseUsageTimer() {
}
/**
* Fill in missing nulls in a list received from Lua
*
* @param $array array List received from Lua
* @param $count integer Number of values that should be in the list
* @return array Non-sparse array
*/
private static function fixNulls( array $array, $count ) {
if ( count( $array ) === $count ) {
return $array;
} else {
return array_replace( array_fill( 1, $count, null ), $array );
}
}
protected function handleCall( $message ) {
$message['args'] = self::fixNulls( $message['args'], $message['nargs'] );
try {
$result = $this->callback( $message['id'], $message['args'] );
} catch ( Scribunto_LuaError $e ) {
return array(
'op' => 'error',
'value' => $e->getLuaMessage() );
}
// Convert to a 1-based array
if ( count( $result ) ) {
$result = array_combine( range( 1, count( $result ) ), $result );
} else {
$result = array();
}
return array(
'op' => 'return',
'nvalues' => count( $result ),
'values' => $result
);
}
protected function callback( $id, array $args ) {
return call_user_func_array( $this->callbacks[$id], $args );
}
protected function handleError( $message ) {
$opts = array();
if ( preg_match( '/^(.*?):(\d+): (.*)$/', $message['value'], $m ) ) {
$opts['module'] = $m[1];
$opts['line'] = $m[2];
$message['value'] = $m[3];
}
if ( isset( $message['trace'] ) ) {
$opts['trace'] = array_values( $message['trace'] );
}
throw $this->engine->newLuaError( $message['value'], $opts );
}
protected function dispatch( $msgToLua ) {
$this->sendMessage( $msgToLua );
while ( true ) {
$msgFromLua = $this->receiveMessage();
switch ( $msgFromLua['op'] ) {
case 'return':
return self::fixNulls( $msgFromLua['values'], $msgFromLua['nvalues'] );
case 'call':
$msgToLua = $this->handleCall( $msgFromLua );
$this->sendMessage( $msgToLua );
break;
case 'error':
$this->handleError( $msgFromLua );
return; // not reached
default:
wfDebug( __METHOD__ .": invalid response op \"{$msgFromLua['op']}\"\n" );
throw $this->engine->newException( 'scribunto-luastandalone-decode-error' );
}
}
}
protected function sendMessage( $msg ) {
$this->debug( "TX ==> {$msg['op']}" );
$this->checkValid();
// Send the message
$encMsg = $this->encodeMessage( $msg );
if ( !fwrite( $this->writePipe, $encMsg ) ) {
// Write error, probably the process has terminated
// If it has, handleIOError() will throw. If not, throw an exception ourselves.
$this->handleIOError();
throw $this->engine->newException( 'scribunto-luastandalone-write-error' );
}
}
protected function receiveMessage() {
$this->checkValid();
// Read the header
$header = fread( $this->readPipe, 16 );
if ( strlen( $header ) !== 16 ) {
$this->handleIOError();
throw $this->engine->newException( 'scribunto-luastandalone-read-error' );
}
$length = $this->decodeHeader( $header );
// Read the reply body
$body = '';
$lengthRemaining = $length;
while ( $lengthRemaining ) {
$buffer = fread( $this->readPipe, $lengthRemaining );
if ( $buffer === false || feof( $this->readPipe ) ) {
$this->handleIOError();
throw $this->engine->newException( 'scribunto-luastandalone-read-error' );
}
$body .= $buffer;
$lengthRemaining -= strlen( $buffer );
}
$body = strtr( $body, array(
'\\r' => "\r",
'\\n' => "\n",
'\\\\' => '\\',
) );
$msg = unserialize( $body );
$this->debug( "RX <== {$msg['op']}" );
return $msg;
}
protected function encodeMessage( $message ) {
$serialized = $this->encodeLuaVar( $message );
$length = strlen( $serialized );
$check = $length * 2 - 1;
return sprintf( '%08x%08x%s', $length, $check, $serialized );
}
protected function encodeLuaVar( $var, $level = 0 ) {
if ( $level > 100 ) {
throw new MWException( __METHOD__.': recursion depth limit exceeded' );
}
$type = gettype( $var );
switch ( $type ) {
case 'boolean':
return $var ? 'true' : 'false';
case 'integer':
return $var;
case 'double':
if ( !is_finite( $var ) ) {
if ( is_nan( $var ) ) {
return '(0/0)';
}
if ( $var === INF ) {
return '(1/0)';
}
if ( $var === -INF ) {
return '(-1/0)';
}
throw new MWException( __METHOD__.': cannot convert non-finite number' );
}
return $var;
case 'string':
return '"' .
strtr( $var, array(
'"' => '\\"',
'\\' => '\\\\',
"\n" => '\\n',
"\r" => '\\r',
"\000" => '\\000',
) ) .
'"';
case 'array':
$s = '{';
foreach ( $var as $key => $element ) {
if ( $s !== '{' ) {
$s .= ',';
}
$s .= '[' . $this->encodeLuaVar( $key, $level + 1 ) . ']' .
'=' . $this->encodeLuaVar( $element, $level + 1 );
}
$s .= '}';
return $s;
case 'object':
if ( !( $var instanceof Scribunto_LuaStandaloneInterpreterFunction ) ) {
throw new MWException( __METHOD__.': unable to convert object of type ' .
get_class( $var ) );
} elseif ( $var->interpreterId !== $this->id ) {
throw new MWException( __METHOD__.': unable to convert function belonging to a different interpreter' );
} else {
return 'chunks[' . intval( $var->id ) . ']';
}
case 'resource':
throw new MWException( __METHOD__.': unable to convert resource' );
case 'NULL':
return 'nil';
default:
throw new MWException( __METHOD__.': unable to convert variable of unknown type' );
}
}
protected function decodeHeader( $header ) {
$length = substr( $header, 0, 8 );
$check = substr( $header, 8, 8 );
if ( !preg_match( '/^[0-9a-f]+$/', $length ) || !preg_match( '/^[0-9a-f]+$/', $check ) ) {
throw $this->engine->newException( 'scribunto-luastandalone-decode-error' );
}
$length = hexdec( $length );
$check = hexdec( $check );
if ( $length * 2 - 1 !== $check ) {
throw $this->engine->newException( 'scribunto-luastandalone-decode-error' );
}
return $length;
}
/**
* @throws ScribuntoException
*/
protected function checkValid() {
if ( !$this->proc ) {
wfDebug( __METHOD__ . ": process already terminated\n" );
if ( $this->exitError ) {
throw $this->exitError;
} else {
throw $this->engine->newException( 'scribunto-luastandalone-gone' );
}
}
}
/**
* @throws ScribuntoException
*/
protected function handleIOError() {
$this->checkValid();
proc_terminate( $this->proc );
$wstatus = proc_close( $this->proc );
$signaled = pcntl_wifsignaled( $wstatus );
$termsig = pcntl_wtermsig( $wstatus );
$exitcode = pcntl_wexitstatus( $wstatus );
$this->proc = false;
if ( $signaled ) {
if ( defined( 'SIGXCPU' ) && $termsig == SIGXCPU ) {
$this->exitError = $this->engine->newException( 'scribunto-common-timeout' );
} else {
$this->exitError = $this->engine->newException( 'scribunto-luastandalone-signal',
array( 'args' => array( $termsig ) ) );
}
} else {
$this->exitError = $this->engine->newException( 'scribunto-luastandalone-exited',
array( 'args' => array( $exitcode ) ) );
}
throw $this->exitError;
}
protected function debug( $msg ) {
if ( $this->enableDebug ) {
wfDebug( "Lua: $msg\n" );
}
}
}
class Scribunto_LuaStandaloneInterpreterFunction {
public static $anyChunksDestroyed = array();
public static $activeChunkIds = array();
/**
* @var int
*/
public $interpreterId;
/**
* @var int
*/
public $id;
/**
* @param int $interpreterId
* @param int $id
*/
function __construct( $interpreterId, $id ) {
$this->interpreterId = $interpreterId;
$this->id = $id;
$this->incrementRefCount();
}
function __clone() {
$this->incrementRefCount();
}
function __wakeup() {
$this->incrementRefCount();
}
function __destruct() {
$this->decrementRefCount();
}
private function incrementRefCount() {
if ( !isset( self::$activeChunkIds[$this->interpreterId] ) ) {
self::$activeChunkIds[$this->interpreterId] = array( $this->id => 1 );
} elseif ( !isset( self::$activeChunkIds[$this->interpreterId][$this->id] ) ) {
self::$activeChunkIds[$this->interpreterId][$this->id] = 1;
} else {
self::$activeChunkIds[$this->interpreterId][$this->id]++;
}
}
private function decrementRefCount() {
if ( isset( self::$activeChunkIds[$this->interpreterId][$this->id] ) ) {
if ( --self::$activeChunkIds[$this->interpreterId][$this->id] <= 0 ) {
unset( self::$activeChunkIds[$this->interpreterId][$this->id] );
self::$anyChunksDestroyed[$this->interpreterId] = true;
}
} else {
self::$anyChunksDestroyed[$this->interpreterId] = true;
}
}
}