ConsoleReaderChildProcessDaemon.php

<?php
 
/*
 *
 *  ____            _        _   __  __ _                  __  __ ____
 * |  _ \ ___   ___| | _____| |_|  \/  (_)_ __   ___      |  \/  |  _ \
 * | |_) / _ \ / __| |/ / _ \ __| |\/| | | '_ \ / _ \_____| |\/| | |_) |
 * |  __/ (_) | (__|   <  __/ |_| |  | | | | | |  __/_____| |  | |  __/
 * |_|   \___/ \___|_|\_\___|\__|_|  |_|_|_| |_|\___|     |_|  |_|_|
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * @author PocketMine Team
 * @link http://www.pocketmine.net/
 *
 *
 */
 
declare(strict_types=1);
 
namespace pocketmine\console;
 
use pocketmine\utils\AssumptionFailedError;
use pocketmine\utils\Utils;
use Symfony\Component\Filesystem\Path;
use function base64_encode;
use function fgets;
use function fopen;
use function mt_rand;
use function preg_replace;
use function proc_close;
use function proc_open;
use function proc_terminate;
use function rtrim;
use function sprintf;
use function stream_select;
use function trim;
use const PHP_BINARY;
 
final class ConsoleReaderChildProcessDaemon{
    public const TOKEN_DELIMITER = ":";
    public const TOKEN_HASH_ALGO = "xxh3";
 
    private \PrefixedLogger $logger;
    private $subprocess;
    private $socket;
    private int $commandTokenSeed;
 
    public function __construct(
        \Logger $logger
    ){
        $this->logger = new \PrefixedLogger($logger, "Console Reader Daemon");
        $this->commandTokenSeed = mt_rand();
        $this->prepareSubprocess();
    }
 
    private function prepareSubprocess() : void{
        //Windows sucks, and likes to corrupt UTF-8 file paths when they travel to the subprocess, so we base64 encode
        //the path to avoid the problem. This is an abysmally shitty hack, but here we are :(
        $sub = Utils::assumeNotFalse(proc_open(
            [
                PHP_BINARY,
                '-dopcache.enable_cli=0',
                '-r',
                sprintf('require base64_decode("%s", true);', base64_encode(Path::join(__DIR__, 'ConsoleReaderChildProcess.php'))),
                (string) $this->commandTokenSeed
            ],
            [
                1 => ['socket'],
                2 => fopen("php://stderr", "w"),
            ],
            $pipes
        ), "Something has gone horribly wrong");
 
        $this->subprocess = $sub;
        $this->socket = $pipes[1];
    }
 
    private function shutdownSubprocess() : void{
        //we have no way to signal to the subprocess to shut down gracefully; besides, Windows sucks, and the subprocess
        //gets stuck in a blocking fgets() read because stream_select() is a hunk of junk (hence the separate process in
        //the first place).
        proc_terminate($this->subprocess);
        proc_close($this->subprocess);
    }
 
    public function readLine() : ?string{
        $r = [$this->socket];
        $w = null;
        $e = null;
        if(stream_select($r, $w, $e, 0, 0) === 1){
            $line = fgets($this->socket);
            if($line === false){
                $this->logger->debug("Lost connection to subprocess, restarting (maybe the child process was killed from outside?)");
                $this->shutdownSubprocess();
                $this->prepareSubprocess();
                return null;
            }
            $line = rtrim($line, "\n");
 
            if($line === ""){
                //keepalive
                return null;
            }
 
            $command = ConsoleReaderChildProcessUtils::parseMessage($line, $this->commandTokenSeed);
            if($command === null){
                //this is not a command - it may be some kind of error output from the subprocess
                //write it directly to the console
                $this->logger->warning("Unexpected output from child process: $line");
                return null;
            }
 
            $command = preg_replace("#\\x1b\\x5b([^\\x1b]*\\x7e|[\\x40-\\x50])#", "", trim($command)) ?? throw new AssumptionFailedError("This regex is assumed to be valid");
            $command = preg_replace('/[[:cntrl:]]/', '', $command) ?? throw new AssumptionFailedError("This regex is assumed to be valid");
 
            return $command !== "" ? $command : null;
        }
 
        return null;
    }
 
    public function quit() : void{
        $this->shutdownSubprocess();
    }
}