PHP limitations set_time_limit workaround

php_limitations_set_time_limit_workaround.php

<?php

$isDefunct = function ($result) {
    return preg_match('/<defunct>$/', $result);
};

$getProcessInfo = function ($pid) {
    return exec("ps --pid $pid | tail -n +2");
};

$isProcessDone = function ($pid) use ($getProcessInfo, $isDefunct) {
    $result = $getProcessInfo($pid);

    return '' === $result || $isDefunct($result);
};

$isProcessRunning = function ($pid) use ($getProcessInfo, $isDefunct) {
    $result = $getProcessInfo($pid);

    return '' !== $result && !$isDefunct($result);
};

$executeMaxTime = function (
    $timeoutMilliSeconds,
    \Closure $doWhat,
    \Closure $onAfterChildKilled = null,
    $checkEveryNMilliSeconds = 1000
) use ($isProcessDone, $isProcessRunning) {
    $checkEveryNMicroSeconds = $checkEveryNMilliSeconds * 1000;

    $pid = pcntl_fork();

    if ($pid == -1) {
        throw new \Exception('Cannot fork.');
    } else if ($pid) {
        for ($i = 0; $i < $timeoutMilliSeconds; $i += $checkEveryNMilliSeconds) {
            if ($isProcessDone($pid)) {
                echo 'Child ended during parent wait.'.PHP_EOL;

                return;
            }

            usleep($checkEveryNMicroSeconds);
        }

        posix_kill($pid, SIGSTOP);

        echo 'Parent stopped child.'.PHP_EOL;

        if ($isProcessRunning($pid)) {
            posix_kill($pid, SIGKILL);

            if ($onAfterChildKilled !== null) {
                $onAfterChildKilled();
            }
        } else {
            echo 'Child won\'t be killed as its done.'.PHP_EOL;
        }

        $status = null;

        pcntl_wait($status); //Protects us against zombies children
    } else {
        $doWhat();
    }
};

$executeMaxTime(
    5000,
    function () {
        for ($i = 0; $i < 10; $i += 1) {
            echo 'Child still alive, not sleepin'.PHP_EOL;

            sleep(1);
        }
    },
    function () {
        echo 'Parent killed child.'.PHP_EOL;
    }
);