Subversion-Projekte lars-tiefland.laravel_shop

<?php

/*

 * This file is part of Psy Shell.

 *

 * (c) 2012-2022 Justin Hileman

 *

 * For the full copyright and license information, please view the LICENSE

 * file that was distributed with this source code.

 */

namespace Psy\ExecutionLoop;

use Psy\Context;

use Psy\Exception\BreakException;

use Psy\Shell;

/**

 * An execution loop listener that forks the process before executing code.

 *

 * This is awesome, as the session won't die prematurely if user input includes

 * a fatal error, such as redeclaring a class or function.

 */

class ProcessForker extends AbstractListener

{

    private $savegame;

    private $up;

    private static $pcntlFunctions = [

        'pcntl_fork',

        'pcntl_signal_dispatch',

        'pcntl_signal',

        'pcntl_waitpid',

        'pcntl_wexitstatus',

    ];

    private static $posixFunctions = [

        'posix_getpid',

        'posix_kill',

    ];

    /**

     * Process forker is supported if pcntl and posix extensions are available.

     *

     * @return bool

     */

    public static function isSupported(): bool

    {

        return self::isPcntlSupported() && !self::disabledPcntlFunctions() && self::isPosixSupported() && !self::disabledPosixFunctions();

    }

    /**

     * Verify that all required pcntl functions are, in fact, available.

     */

    public static function isPcntlSupported(): bool

    {

        foreach (self::$pcntlFunctions as $func) {

            if (!\function_exists($func)) {

                return false;

            }

        }

        return true;

    }

    /**

     * Check whether required pcntl functions are disabled.

     */

    public static function disabledPcntlFunctions()

    {

        return self::checkDisabledFunctions(self::$pcntlFunctions);

    }

    /**

     * Verify that all required posix functions are, in fact, available.

     */

    public static function isPosixSupported(): bool

    {

        foreach (self::$posixFunctions as $func) {

            if (!\function_exists($func)) {

                return false;

            }

        }

        return true;

    }

    /**

     * Check whether required posix functions are disabled.

     */

    public static function disabledPosixFunctions()

    {

        return self::checkDisabledFunctions(self::$posixFunctions);

    }

    private static function checkDisabledFunctions(array $functions): array

    {

        return \array_values(\array_intersect($functions, \array_map('strtolower', \array_map('trim', \explode(',', \ini_get('disable_functions'))))));

    }

    /**

     * Forks into a main and a loop process.

     *

     * The loop process will handle the evaluation of all instructions, then

     * return its state via a socket upon completion.

     *

     * @param Shell $shell

     */

    public function beforeRun(Shell $shell)

    {

        list($up, $down) = \stream_socket_pair(\STREAM_PF_UNIX, \STREAM_SOCK_STREAM, \STREAM_IPPROTO_IP);

        if (!$up) {

            throw new \RuntimeException('Unable to create socket pair');

        }

        $pid = \pcntl_fork();

        if ($pid < 0) {

            throw new \RuntimeException('Unable to start execution loop');

        } elseif ($pid > 0) {

            // This is the main thread. We'll just wait for a while.

            // We won't be needing this one.

            \fclose($up);

            // Wait for a return value from the loop process.

            $read = [$down];

            $write = null;

            $except = null;

            do {

                $n = @\stream_select($read, $write, $except, null);

                if ($n === 0) {

                    throw new \RuntimeException('Process timed out waiting for execution loop');

                }

                if ($n === false) {

                    $err = \error_get_last();

                    if (!isset($err['message']) || \stripos($err['message'], 'interrupted system call') === false) {

                        $msg = $err['message'] ?

                            \sprintf('Error waiting for execution loop: %s', $err['message']) :

                            'Error waiting for execution loop';

                        throw new \RuntimeException($msg);

                    }

                }

            } while ($n < 1);

            $content = \stream_get_contents($down);

            \fclose($down);

            if ($content) {

                $shell->setScopeVariables(@\unserialize($content));

            }

            throw new BreakException('Exiting main thread');

        }

        // This is the child process. It's going to do all the work.

        if (!@\cli_set_process_title('psysh (loop)')) {

            // Fall back to `setproctitle` if that wasn't succesful.

            if (\function_exists('setproctitle')) {

                @\setproctitle('psysh (loop)');

            }

        }

        // We won't be needing this one.

        \fclose($down);

        // Save this; we'll need to close it in `afterRun`

        $this->up = $up;

    }

    /**

     * Create a savegame at the start of each loop iteration.

     *

     * @param Shell $shell

     */

    public function beforeLoop(Shell $shell)

    {

        $this->createSavegame();

    }

    /**

     * Clean up old savegames at the end of each loop iteration.

     *

     * @param Shell $shell

     */

    public function afterLoop(Shell $shell)

    {

        // if there's an old savegame hanging around, let's kill it.

        if (isset($this->savegame)) {

            \posix_kill($this->savegame, \SIGKILL);

            \pcntl_signal_dispatch();

        }

    }

    /**

     * After the REPL session ends, send the scope variables back up to the main

     * thread (if this is a child thread).

     *

     * @param Shell $shell

     */

    public function afterRun(Shell $shell)

    {

        // We're a child thread. Send the scope variables back up to the main thread.

        if (isset($this->up)) {

            \fwrite($this->up, $this->serializeReturn($shell->getScopeVariables(false)));

            \fclose($this->up);

            \posix_kill(\posix_getpid(), \SIGKILL);

        }

    }

    /**

     * Create a savegame fork.

     *

     * The savegame contains the current execution state, and can be resumed in

     * the event that the worker dies unexpectedly (for example, by encountering

     * a PHP fatal error).

     */

    private function createSavegame()

    {

        // the current process will become the savegame

        $this->savegame = \posix_getpid();

        $pid = \pcntl_fork();

        if ($pid < 0) {

            throw new \RuntimeException('Unable to create savegame fork');

        } elseif ($pid > 0) {

            // we're the savegame now... let's wait and see what happens

            \pcntl_waitpid($pid, $status);

            // worker exited cleanly, let's bail

            if (!\pcntl_wexitstatus($status)) {

                \posix_kill(\posix_getpid(), \SIGKILL);

            }

            // worker didn't exit cleanly, we'll need to have another go

            $this->createSavegame();

        }

    }

    /**

     * Serialize all serializable return values.

     *

     * A naïve serialization will run into issues if there is a Closure or

     * SimpleXMLElement (among other things) in scope when exiting the execution

     * loop. We'll just ignore these unserializable classes, and serialize what

     * we can.

     *

     * @param array $return

     *

     * @return string

     */

    private function serializeReturn(array $return): string

    {

        $serializable = [];

        foreach ($return as $key => $value) {

            // No need to return magic variables

            if (Context::isSpecialVariableName($key)) {

                continue;

            }

            // Resources and Closures don't error, but they don't serialize well either.

            if (\is_resource($value) || $value instanceof \Closure) {

                continue;

            }

            if (\version_compare(\PHP_VERSION, '8.1', '>=') && $value instanceof \UnitEnum) {

                // Enums defined in the REPL session can't be unserialized.

                $ref = new \ReflectionObject($value);

                if (\strpos($ref->getFileName(), ": eval()'d code") !== false) {

                    continue;

                }

            }

            try {

                @\serialize($value);

                $serializable[$key] = $value;

            } catch (\Throwable $e) {

                // we'll just ignore this one...

            }

        }

        return @\serialize($serializable);

    }

}