Process.php

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<?php
 
/*
 * This file is part of the Symfony package.
 *
 * (c) Fabien Potencier <fabien@symfony.com>
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */
 
namespace Symfony\Component\Process;
 
use Symfony\Component\Process\Exception\InvalidArgumentException;
use Symfony\Component\Process\Exception\LogicException;
use Symfony\Component\Process\Exception\ProcessFailedException;
use Symfony\Component\Process\Exception\ProcessTimedOutException;
use Symfony\Component\Process\Exception\RuntimeException;
use Symfony\Component\Process\Pipes\PipesInterface;
use Symfony\Component\Process\Pipes\UnixPipes;
use Symfony\Component\Process\Pipes\WindowsPipes;
 
class Process implements \IteratorAggregate
{
    const ERR = 'err';
    const OUT = 'out';
 
    const STATUS_READY = 'ready';
    const STATUS_STARTED = 'started';
    const STATUS_TERMINATED = 'terminated';
 
    const STDIN = 0;
    const STDOUT = 1;
    const STDERR = 2;
 
    // Timeout Precision in seconds.
    const TIMEOUT_PRECISION = 0.2;
 
    const ITER_NON_BLOCKING = 1; // By default, iterating over outputs is a blocking call, use this flag to make it non-blocking
    const ITER_KEEP_OUTPUT = 2;  // By default, outputs are cleared while iterating, use this flag to keep them in memory
    const ITER_SKIP_OUT = 4;     // Use this flag to skip STDOUT while iterating
    const ITER_SKIP_ERR = 8;     // Use this flag to skip STDERR while iterating
 
    private $callback;
    private $hasCallback = false;
    private $commandline;
    private $cwd;
    private $env;
    private $input;
    private $starttime;
    private $lastOutputTime;
    private $timeout;
    private $idleTimeout;
    private $options;
    private $exitcode;
    private $fallbackStatus = array();
    private $processInformation;
    private $outputDisabled = false;
    private $stdout;
    private $stderr;
    private $enhanceWindowsCompatibility = true;
    private $enhanceSigchildCompatibility;
    private $process;
    private $status = self::STATUS_READY;
    private $incrementalOutputOffset = 0;
    private $incrementalErrorOutputOffset = 0;
    private $tty;
    private $pty;
 
    private $useFileHandles = false;
    private $processPipes;
 
    private $latestSignal;
 
    private static $sigchild;
 
    public static $exitCodes = array(
        0 => 'OK',
        1 => 'General error',
        2 => 'Misuse of shell builtins',
 
        126 => 'Invoked command cannot execute',
        127 => 'Command not found',
        128 => 'Invalid exit argument',
 
        // signals
        129 => 'Hangup',
        130 => 'Interrupt',
        131 => 'Quit and dump core',
        132 => 'Illegal instruction',
        133 => 'Trace/breakpoint trap',
        134 => 'Process aborted',
        135 => 'Bus error: "access to undefined portion of memory object"',
        136 => 'Floating point exception: "erroneous arithmetic operation"',
        137 => 'Kill (terminate immediately)',
        138 => 'User-defined 1',
        139 => 'Segmentation violation',
        140 => 'User-defined 2',
        141 => 'Write to pipe with no one reading',
        142 => 'Signal raised by alarm',
        143 => 'Termination (request to terminate)',
        // 144 - not defined
        145 => 'Child process terminated, stopped (or continued*)',
        146 => 'Continue if stopped',
        147 => 'Stop executing temporarily',
        148 => 'Terminal stop signal',
        149 => 'Background process attempting to read from tty ("in")',
        150 => 'Background process attempting to write to tty ("out")',
        151 => 'Urgent data available on socket',
        152 => 'CPU time limit exceeded',
        153 => 'File size limit exceeded',
        154 => 'Signal raised by timer counting virtual time: "virtual timer expired"',
        155 => 'Profiling timer expired',
        // 156 - not defined
        157 => 'Pollable event',
        // 158 - not defined
        159 => 'Bad syscall',
    );
 
    public function __construct($commandline, $cwd = null, array $env = null, $input = null, $timeout = 60, array $options = array())
    {
        if (!function_exists('proc_open')) {
            throw new RuntimeException('The Process class relies on proc_open, which is not available on your PHP installation.');
        }
 
        $this->commandline = $commandline;
        $this->cwd = $cwd;
 
        // on Windows, if the cwd changed via chdir(), proc_open defaults to the dir where PHP was started
        // on Gnu/Linux, PHP builds with --enable-maintainer-zts are also affected
        // @see : https://bugs.php.net/bug.php?id=51800
        // @see : https://bugs.php.net/bug.php?id=50524
        if (null === $this->cwd && (defined('ZEND_THREAD_SAFE') || '\\' === DIRECTORY_SEPARATOR)) {
            $this->cwd = getcwd();
        }
        if (null !== $env) {
            $this->setEnv($env);
        }
 
        $this->setInput($input);
        $this->setTimeout($timeout);
        $this->useFileHandles = '\\' === DIRECTORY_SEPARATOR;
        $this->pty = false;
        $this->enhanceWindowsCompatibility = true;
        $this->enhanceSigchildCompatibility = '\\' !== DIRECTORY_SEPARATOR && $this->isSigchildEnabled();
        $this->options = array_replace(array('suppress_errors' => true, 'binary_pipes' => true), $options);
    }
 
    public function __destruct()
    {
        $this->stop(0);
    }
 
    public function __clone()
    {
        $this->resetProcessData();
    }
 
    public function run($callback = null)
    {
        $this->start($callback);
 
        return $this->wait();
    }
 
    public function mustRun(callable $callback = null)
    {
        if (!$this->enhanceSigchildCompatibility && $this->isSigchildEnabled()) {
            throw new RuntimeException('This PHP has been compiled with --enable-sigchild. You must use setEnhanceSigchildCompatibility() to use this method.');
        }
 
        if (0 !== $this->run($callback)) {
            throw new ProcessFailedException($this);
        }
 
        return $this;
    }
 
    public function start(callable $callback = null)
    {
        if ($this->isRunning()) {
            throw new RuntimeException('Process is already running');
        }
 
        $this->resetProcessData();
        $this->starttime = $this->lastOutputTime = microtime(true);
        $this->callback = $this->buildCallback($callback);
        $this->hasCallback = null !== $callback;
        $descriptors = $this->getDescriptors();
 
        $commandline = $this->commandline;
 
        if ('\\' === DIRECTORY_SEPARATOR && $this->enhanceWindowsCompatibility) {
            $commandline = 'cmd /V:ON /E:ON /D /C "('.$commandline.')';
            foreach ($this->processPipes->getFiles() as $offset => $filename) {
                $commandline .= ' '.$offset.'>'.ProcessUtils::escapeArgument($filename);
            }
            $commandline .= '"';
 
            if (!isset($this->options['bypass_shell'])) {
                $this->options['bypass_shell'] = true;
            }
        } elseif (!$this->useFileHandles && $this->enhanceSigchildCompatibility && $this->isSigchildEnabled()) {
            // last exit code is output on the fourth pipe and caught to work around --enable-sigchild
            $descriptors[3] = array('pipe', 'w');
 
            // See https://unix.stackexchange.com/questions/71205/background-process-pipe-input
            $commandline = '{ ('.$this->commandline.') <&3 3<&- 3>/dev/null & } 3<&0;';
            $commandline .= 'pid=$!; echo $pid >&3; wait $pid; code=$?; echo $code >&3; exit $code';
 
            // Workaround for the bug, when PTS functionality is enabled.
            // @see : https://bugs.php.net/69442
            $ptsWorkaround = fopen(__FILE__, 'r');
        }
 
        $this->process = proc_open($commandline, $descriptors, $this->processPipes->pipes, $this->cwd, $this->env, $this->options);
 
        if (!is_resource($this->process)) {
            throw new RuntimeException('Unable to launch a new process.');
        }
        $this->status = self::STATUS_STARTED;
 
        if (isset($descriptors[3])) {
            $this->fallbackStatus['pid'] = (int) fgets($this->processPipes->pipes[3]);
        }
 
        if ($this->tty) {
            return;
        }
 
        $this->updateStatus(false);
        $this->checkTimeout();
    }
 
    public function restart(callable $callback = null)
    {
        if ($this->isRunning()) {
            throw new RuntimeException('Process is already running');
        }
 
        $process = clone $this;
        $process->start($callback);
 
        return $process;
    }
 
    public function wait(callable $callback = null)
    {
        $this->requireProcessIsStarted(__FUNCTION__);
 
        $this->updateStatus(false);
 
        if (null !== $callback) {
            if (!$this->processPipes->haveReadSupport()) {
                $this->stop(0);
                throw new \LogicException('Pass the callback to the Process:start method or enableOutput to use a callback with Process::wait');
            }
            $this->callback = $this->buildCallback($callback);
        }
 
        do {
            $this->checkTimeout();
            $running = '\\' === DIRECTORY_SEPARATOR ? $this->isRunning() : $this->processPipes->areOpen();
            $this->readPipes($running, '\\' !== DIRECTORY_SEPARATOR || !$running);
        } while ($running);
 
        while ($this->isRunning()) {
            usleep(1000);
        }
 
        if ($this->processInformation['signaled'] && $this->processInformation['termsig'] !== $this->latestSignal) {
            throw new RuntimeException(sprintf('The process has been signaled with signal "%s".', $this->processInformation['termsig']));
        }
 
        return $this->exitcode;
    }
 
    public function getPid()
    {
        return $this->isRunning() ? $this->processInformation['pid'] : null;
    }
 
    public function signal($signal)
    {
        $this->doSignal($signal, true);
 
        return $this;
    }
 
    public function disableOutput()
    {
        if ($this->isRunning()) {
            throw new RuntimeException('Disabling output while the process is running is not possible.');
        }
        if (null !== $this->idleTimeout) {
            throw new LogicException('Output can not be disabled while an idle timeout is set.');
        }
 
        $this->outputDisabled = true;
 
        return $this;
    }
 
    public function enableOutput()
    {
        if ($this->isRunning()) {
            throw new RuntimeException('Enabling output while the process is running is not possible.');
        }
 
        $this->outputDisabled = false;
 
        return $this;
    }
 
    public function isOutputDisabled()
    {
        return $this->outputDisabled;
    }
 
    public function getOutput()
    {
        $this->readPipesForOutput(__FUNCTION__);
 
        if (false === $ret = stream_get_contents($this->stdout, -1, 0)) {
            return '';
        }
 
        return $ret;
    }
 
    public function getIncrementalOutput()
    {
        $this->readPipesForOutput(__FUNCTION__);
 
        $latest = stream_get_contents($this->stdout, -1, $this->incrementalOutputOffset);
        $this->incrementalOutputOffset = ftell($this->stdout);
 
        if (false === $latest) {
            return '';
        }
 
        return $latest;
    }
 
    public function getIterator($flags = 0)
    {
        $this->readPipesForOutput(__FUNCTION__, false);
 
        $clearOutput = !(self::ITER_KEEP_OUTPUT & $flags);
        $blocking = !(self::ITER_NON_BLOCKING & $flags);
        $yieldOut = !(self::ITER_SKIP_OUT & $flags);
        $yieldErr = !(self::ITER_SKIP_ERR & $flags);
 
        while (null !== $this->callback || ($yieldOut && !feof($this->stdout)) || ($yieldErr && !feof($this->stderr))) {
            if ($yieldOut) {
                $out = stream_get_contents($this->stdout, -1, $this->incrementalOutputOffset);
 
                if (isset($out[0])) {
                    if ($clearOutput) {
                        $this->clearOutput();
                    } else {
                        $this->incrementalOutputOffset = ftell($this->stdout);
                    }
 
                    yield self::OUT => $out;
                }
            }
 
            if ($yieldErr) {
                $err = stream_get_contents($this->stderr, -1, $this->incrementalErrorOutputOffset);
 
                if (isset($err[0])) {
                    if ($clearOutput) {
                        $this->clearErrorOutput();
                    } else {
                        $this->incrementalErrorOutputOffset = ftell($this->stderr);
                    }
 
                    yield self::ERR => $err;
                }
            }
 
            if (!$blocking && !isset($out[0]) && !isset($err[0])) {
                yield self::OUT => '';
            }
 
            $this->readPipesForOutput(__FUNCTION__, $blocking);
        }
    }
 
    public function clearOutput()
    {
        ftruncate($this->stdout, 0);
        fseek($this->stdout, 0);
        $this->incrementalOutputOffset = 0;
 
        return $this;
    }
 
    public function getErrorOutput()
    {
        $this->readPipesForOutput(__FUNCTION__);
 
        if (false === $ret = stream_get_contents($this->stderr, -1, 0)) {
            return '';
        }
 
        return $ret;
    }
 
    public function getIncrementalErrorOutput()
    {
        $this->readPipesForOutput(__FUNCTION__);
 
        $latest = stream_get_contents($this->stderr, -1, $this->incrementalErrorOutputOffset);
        $this->incrementalErrorOutputOffset = ftell($this->stderr);
 
        if (false === $latest) {
            return '';
        }
 
        return $latest;
    }
 
    public function clearErrorOutput()
    {
        ftruncate($this->stderr, 0);
        fseek($this->stderr, 0);
        $this->incrementalErrorOutputOffset = 0;
 
        return $this;
    }
 
    public function getExitCode()
    {
        if (!$this->enhanceSigchildCompatibility && $this->isSigchildEnabled()) {
            throw new RuntimeException('This PHP has been compiled with --enable-sigchild. You must use setEnhanceSigchildCompatibility() to use this method.');
        }
 
        $this->updateStatus(false);
 
        return $this->exitcode;
    }
 
    public function getExitCodeText()
    {
        if (null === $exitcode = $this->getExitCode()) {
            return;
        }
 
        return isset(self::$exitCodes[$exitcode]) ? self::$exitCodes[$exitcode] : 'Unknown error';
    }
 
    public function isSuccessful()
    {
        return 0 === $this->getExitCode();
    }
 
    public function hasBeenSignaled()
    {
        $this->requireProcessIsTerminated(__FUNCTION__);
 
        if (!$this->enhanceSigchildCompatibility && $this->isSigchildEnabled()) {
            throw new RuntimeException('This PHP has been compiled with --enable-sigchild. Term signal can not be retrieved.');
        }
 
        return $this->processInformation['signaled'];
    }
 
    public function getTermSignal()
    {
        $this->requireProcessIsTerminated(__FUNCTION__);
 
        if ($this->isSigchildEnabled() && (!$this->enhanceSigchildCompatibility || -1 === $this->processInformation['termsig'])) {
            throw new RuntimeException('This PHP has been compiled with --enable-sigchild. Term signal can not be retrieved.');
        }
 
        return $this->processInformation['termsig'];
    }
 
    public function hasBeenStopped()
    {
        $this->requireProcessIsTerminated(__FUNCTION__);
 
        return $this->processInformation['stopped'];
    }
 
    public function getStopSignal()
    {
        $this->requireProcessIsTerminated(__FUNCTION__);
 
        return $this->processInformation['stopsig'];
    }
 
    public function isRunning()
    {
        if (self::STATUS_STARTED !== $this->status) {
            return false;
        }
 
        $this->updateStatus(false);
 
        return $this->processInformation['running'];
    }
 
    public function isStarted()
    {
        return $this->status != self::STATUS_READY;
    }
 
    public function isTerminated()
    {
        $this->updateStatus(false);
 
        return $this->status == self::STATUS_TERMINATED;
    }
 
    public function getStatus()
    {
        $this->updateStatus(false);
 
        return $this->status;
    }
 
    public function stop($timeout = 10, $signal = null)
    {
        $timeoutMicro = microtime(true) + $timeout;
        if ($this->isRunning()) {
            // given `SIGTERM` may not be defined and that `proc_terminate` uses the constant value and not the constant itself, we use the same here
            $this->doSignal(15, false);
            do {
                usleep(1000);
            } while ($this->isRunning() && microtime(true) < $timeoutMicro);
 
            if ($this->isRunning()) {
                // Avoid exception here: process is supposed to be running, but it might have stopped just
                // after this line. In any case, let's silently discard the error, we cannot do anything.
                $this->doSignal($signal ?: 9, false);
            }
        }
 
        if ($this->isRunning()) {
            if (isset($this->fallbackStatus['pid'])) {
                unset($this->fallbackStatus['pid']);
 
                return $this->stop(0, $signal);
            }
            $this->close();
        }
 
        return $this->exitcode;
    }
 
    public function addOutput($line)
    {
        $this->lastOutputTime = microtime(true);
 
        fseek($this->stdout, 0, SEEK_END);
        fwrite($this->stdout, $line);
        fseek($this->stdout, $this->incrementalOutputOffset);
    }
 
    public function addErrorOutput($line)
    {
        $this->lastOutputTime = microtime(true);
 
        fseek($this->stderr, 0, SEEK_END);
        fwrite($this->stderr, $line);
        fseek($this->stderr, $this->incrementalErrorOutputOffset);
    }
 
    public function getCommandLine()
    {
        return $this->commandline;
    }
 
    public function setCommandLine($commandline)
    {
        $this->commandline = $commandline;
 
        return $this;
    }
 
    public function getTimeout()
    {
        return $this->timeout;
    }
 
    public function getIdleTimeout()
    {
        return $this->idleTimeout;
    }
 
    public function setTimeout($timeout)
    {
        $this->timeout = $this->validateTimeout($timeout);
 
        return $this;
    }
 
    public function setIdleTimeout($timeout)
    {
        if (null !== $timeout && $this->outputDisabled) {
            throw new LogicException('Idle timeout can not be set while the output is disabled.');
        }
 
        $this->idleTimeout = $this->validateTimeout($timeout);
 
        return $this;
    }
 
    public function setTty($tty)
    {
        if ('\\' === DIRECTORY_SEPARATOR && $tty) {
            throw new RuntimeException('TTY mode is not supported on Windows platform.');
        }
        if ($tty && (!file_exists('/dev/tty') || !is_readable('/dev/tty'))) {
            throw new RuntimeException('TTY mode requires /dev/tty to be readable.');
        }
 
        $this->tty = (bool) $tty;
 
        return $this;
    }
 
    public function isTty()
    {
        return $this->tty;
    }
 
    public function setPty($bool)
    {
        $this->pty = (bool) $bool;
 
        return $this;
    }
 
    public function isPty()
    {
        return $this->pty;
    }
 
    public function getWorkingDirectory()
    {
        if (null === $this->cwd) {
            // getcwd() will return false if any one of the parent directories does not have
            // the readable or search mode set, even if the current directory does
            return getcwd() ?: null;
        }
 
        return $this->cwd;
    }
 
    public function setWorkingDirectory($cwd)
    {
        $this->cwd = $cwd;
 
        return $this;
    }
 
    public function getEnv()
    {
        return $this->env;
    }
 
    public function setEnv(array $env)
    {
        // Process can not handle env values that are arrays
        $env = array_filter($env, function ($value) {
            return !is_array($value);
        });
 
        $this->env = array();
        foreach ($env as $key => $value) {
            $this->env[$key] = (string) $value;
        }
 
        return $this;
    }
 
    public function getInput()
    {
        return $this->input;
    }
 
    public function setInput($input)
    {
        if ($this->isRunning()) {
            throw new LogicException('Input can not be set while the process is running.');
        }
 
        $this->input = ProcessUtils::validateInput(__METHOD__, $input);
 
        return $this;
    }
 
    public function getOptions()
    {
        return $this->options;
    }
 
    public function setOptions(array $options)
    {
        $this->options = $options;
 
        return $this;
    }
 
    public function getEnhanceWindowsCompatibility()
    {
        return $this->enhanceWindowsCompatibility;
    }
 
    public function setEnhanceWindowsCompatibility($enhance)
    {
        $this->enhanceWindowsCompatibility = (bool) $enhance;
 
        return $this;
    }
 
    public function getEnhanceSigchildCompatibility()
    {
        return $this->enhanceSigchildCompatibility;
    }
 
    public function setEnhanceSigchildCompatibility($enhance)
    {
        $this->enhanceSigchildCompatibility = (bool) $enhance;
 
        return $this;
    }
 
    public function checkTimeout()
    {
        if ($this->status !== self::STATUS_STARTED) {
            return;
        }
 
        if (null !== $this->timeout && $this->timeout < microtime(true) - $this->starttime) {
            $this->stop(0);
 
            throw new ProcessTimedOutException($this, ProcessTimedOutException::TYPE_GENERAL);
        }
 
        if (null !== $this->idleTimeout && $this->idleTimeout < microtime(true) - $this->lastOutputTime) {
            $this->stop(0);
 
            throw new ProcessTimedOutException($this, ProcessTimedOutException::TYPE_IDLE);
        }
    }
 
    public static function isPtySupported()
    {
        static $result;
 
        if (null !== $result) {
            return $result;
        }
 
        if ('\\' === DIRECTORY_SEPARATOR) {
            return $result = false;
        }
 
        return $result = (bool) @proc_open('echo 1', array(array('pty'), array('pty'), array('pty')), $pipes);
    }
 
    private function getDescriptors()
    {
        if ($this->input instanceof \Iterator) {
            $this->input->rewind();
        }
        if ('\\' === DIRECTORY_SEPARATOR) {
            $this->processPipes = new WindowsPipes($this->input, !$this->outputDisabled || $this->hasCallback);
        } else {
            $this->processPipes = new UnixPipes($this->isTty(), $this->isPty(), $this->input, !$this->outputDisabled || $this->hasCallback);
        }
 
        return $this->processPipes->getDescriptors();
    }
 
    protected function buildCallback(callable $callback = null)
    {
        if ($this->outputDisabled) {
            return function ($type, $data) use ($callback) {
                if (null !== $callback) {
                    call_user_func($callback, $type, $data);
                }
            };
        }
 
        $out = self::OUT;
 
        return function ($type, $data) use ($callback, $out) {
            if ($out == $type) {
                $this->addOutput($data);
            } else {
                $this->addErrorOutput($data);
            }
 
            if (null !== $callback) {
                call_user_func($callback, $type, $data);
            }
        };
    }
 
    protected function updateStatus($blocking)
    {
        if (self::STATUS_STARTED !== $this->status) {
            return;
        }
 
        $this->processInformation = proc_get_status($this->process);
        $running = $this->processInformation['running'];
 
        $this->readPipes($running && $blocking, '\\' !== DIRECTORY_SEPARATOR || !$running);
 
        if ($this->fallbackStatus && $this->enhanceSigchildCompatibility && $this->isSigchildEnabled()) {
            $this->processInformation = $this->fallbackStatus + $this->processInformation;
        }
 
        if (!$running) {
            $this->close();
        }
    }
 
    protected function isSigchildEnabled()
    {
        if (null !== self::$sigchild) {
            return self::$sigchild;
        }
 
        if (!function_exists('phpinfo') || defined('HHVM_VERSION')) {
            return self::$sigchild = false;
        }
 
        ob_start();
        phpinfo(INFO_GENERAL);
 
        return self::$sigchild = false !== strpos(ob_get_clean(), '--enable-sigchild');
    }
 
    private function readPipesForOutput($caller, $blocking = false)
    {
        if ($this->outputDisabled) {
            throw new LogicException('Output has been disabled.');
        }
 
        $this->requireProcessIsStarted($caller);
 
        $this->updateStatus($blocking);
    }
 
    private function validateTimeout($timeout)
    {
        $timeout = (float) $timeout;
 
        if (0.0 === $timeout) {
            $timeout = null;
        } elseif ($timeout < 0) {
            throw new InvalidArgumentException('The timeout value must be a valid positive integer or float number.');
        }
 
        return $timeout;
    }
 
    private function readPipes($blocking, $close)
    {
        $result = $this->processPipes->readAndWrite($blocking, $close);
 
        $callback = $this->callback;
        foreach ($result as $type => $data) {
            if (3 !== $type) {
                $callback($type === self::STDOUT ? self::OUT : self::ERR, $data);
            } elseif (!isset($this->fallbackStatus['signaled'])) {
                $this->fallbackStatus['exitcode'] = (int) $data;
            }
        }
    }
 
    private function close()
    {
        $this->processPipes->close();
        if (is_resource($this->process)) {
            proc_close($this->process);
        }
        $this->exitcode = $this->processInformation['exitcode'];
        $this->status = self::STATUS_TERMINATED;
 
        if (-1 === $this->exitcode) {
            if ($this->processInformation['signaled'] && 0 < $this->processInformation['termsig']) {
                // if process has been signaled, no exitcode but a valid termsig, apply Unix convention
                $this->exitcode = 128 + $this->processInformation['termsig'];
            } elseif ($this->enhanceSigchildCompatibility && $this->isSigchildEnabled()) {
                $this->processInformation['signaled'] = true;
                $this->processInformation['termsig'] = -1;
            }
        }
 
        // Free memory from self-reference callback created by buildCallback
        // Doing so in other contexts like __destruct or by garbage collector is ineffective
        // Now pipes are closed, so the callback is no longer necessary
        $this->callback = null;
 
        return $this->exitcode;
    }
 
    private function resetProcessData()
    {
        $this->starttime = null;
        $this->callback = null;
        $this->exitcode = null;
        $this->fallbackStatus = array();
        $this->processInformation = null;
        $this->stdout = fopen('php://temp/maxmemory:'.(1024 * 1024), 'wb+');
        $this->stderr = fopen('php://temp/maxmemory:'.(1024 * 1024), 'wb+');
        $this->process = null;
        $this->latestSignal = null;
        $this->status = self::STATUS_READY;
        $this->incrementalOutputOffset = 0;
        $this->incrementalErrorOutputOffset = 0;
    }
 
    private function doSignal($signal, $throwException)
    {
        if (null === $pid = $this->getPid()) {
            if ($throwException) {
                throw new LogicException('Can not send signal on a non running process.');
            }
 
            return false;
        }
 
        if ('\\' === DIRECTORY_SEPARATOR) {
            exec(sprintf('taskkill /F /T /PID %d 2>&1', $pid), $output, $exitCode);
            if ($exitCode && $this->isRunning()) {
                if ($throwException) {
                    throw new RuntimeException(sprintf('Unable to kill the process (%s).', implode(' ', $output)));
                }
 
                return false;
            }
        } else {
            if (!$this->enhanceSigchildCompatibility || !$this->isSigchildEnabled()) {
                $ok = @proc_terminate($this->process, $signal);
            } elseif (function_exists('posix_kill')) {
                $ok = @posix_kill($pid, $signal);
            } elseif ($ok = proc_open(sprintf('kill -%d %d', $signal, $pid), array(2 => array('pipe', 'w')), $pipes)) {
                $ok = false === fgets($pipes[2]);
            }
            if (!$ok) {
                if ($throwException) {
                    throw new RuntimeException(sprintf('Error while sending signal `%s`.', $signal));
                }
 
                return false;
            }
        }
 
        $this->latestSignal = (int) $signal;
        $this->fallbackStatus['signaled'] = true;
        $this->fallbackStatus['exitcode'] = -1;
        $this->fallbackStatus['termsig'] = $this->latestSignal;
 
        return true;
    }
 
    private function requireProcessIsStarted($functionName)
    {
        if (!$this->isStarted()) {
            throw new LogicException(sprintf('Process must be started before calling %s.', $functionName));
        }
    }
 
    private function requireProcessIsTerminated($functionName)
    {
        if (!$this->isTerminated()) {
            throw new LogicException(sprintf('Process must be terminated before calling %s.', $functionName));
        }
    }
}