Proyectos de Subversion Moodle

<?php

// This file is part of Moodle - http://moodle.org/

//

// Moodle is free software: you can redistribute it and/or modify

// it under the terms of the GNU General Public License as published by

// the Free Software Foundation, either version 3 of the License, or

// (at your option) any later version.

//

// Moodle is distributed in the hope that it will be useful,

// but WITHOUT ANY WARRANTY; without even the implied warranty of

// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

// GNU General Public License for more details.

//

// You should have received a copy of the GNU General Public License

// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.

/**

 * Shutdown management class.

 *

 * @package    core

 * @copyright  2013 Petr Skoda {@link http://skodak.org}

 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later

 */

defined('MOODLE_INTERNAL') || die();

/**

 * Shutdown management class.

 *

 * @package    core

 * @copyright  2013 Petr Skoda {@link http://skodak.org}

 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later

 */

class core_shutdown_manager {

    /** @var array list of custom callbacks */

    protected static $callbacks = [];

    /** @var array list of custom signal callbacks */

    protected static $signalcallbacks = [];

    /** @var bool is this manager already registered? */

    protected static $registered = false;

    /**

     * Register self as main shutdown handler.

     *

     * @private to be called from lib/setup.php only!

     */

    public static function initialize() {

        if (self::$registered) {

            debugging('Shutdown manager is already initialised!');

        }

        self::$registered = true;

        register_shutdown_function(array('core_shutdown_manager', 'shutdown_handler'));

        // Signal handlers are recommended for the best possible shutdown handling.

        // They require the 'pcntl' extension to be loaded and the following functions to be available:

        // 'pcntl_async_signals'

        // 'pcntl_signal'

        // The 'pcntl' extension is optional and not available on Windows.

        if (extension_loaded('pcntl')) {

            if (function_exists('pcntl_async_signals')) {

                // We capture and handle SIGINT (Ctrl+C) and SIGTERM (termination requested).

                pcntl_async_signals(true);

            }

            if (function_exists('pcntl_signal')) {

                pcntl_signal(SIGINT, ['core_shutdown_manager', 'signal_handler']);

                pcntl_signal(SIGTERM, ['core_shutdown_manager', 'signal_handler']);

            }

        }

    }

    /**

     * Signal handler for SIGINT, and SIGTERM.

     *

     * @param   int     $signo The signal being handled

     */

    public static function signal_handler(int $signo) {

        // Note: There is no need to manually call the shutdown handler.

        // The fact that we are calling exit() in this script means that the standard shutdown handling is performed

        // anyway.

        switch ($signo) {

            case SIGTERM:

                // Replicate native behaviour.

                echo "Terminated: {$signo}\n";

                // The standard exit code for SIGTERM is 143.

                $exitcode = 143;

                break;

            case SIGINT:

                // Replicate native behaviour.

                echo "\n";

                // The standard exit code for SIGINT (Ctrl+C) is 130.

                $exitcode = 130;

                break;

            default:

                // The signal handler was called with a signal it was not expecting.

                // We should exit and complain.

                echo "Warning: \core_shutdown_manager::signal_handler() was called with an unexpected signal ({$signo}).\n";

                $exitcode = 1;

        }

        // Normally we should exit unless a callback tells us to wait.

        $shouldexit = true;

        foreach (self::$signalcallbacks as $data) {

            list($callback, $params) = $data;

            try {

                array_unshift($params, $signo);

                $shouldexit = call_user_func_array($callback, $params) && $shouldexit;

            } catch (Throwable $e) {

                // phpcs:ignore

                error_log('Exception ignored in signal function ' . get_callable_name($callback) . ': ' . $e->getMessage());

            }

        }

        if ($shouldexit) {

            exit ($exitcode);

        }

    }

    /**

     * Register custom signal handler function.

     *

     * If a handler returns false the signal will be ignored.

     *

     * @param callable $callback

     * @param array $params

     * @return void

     */

    public static function register_signal_handler($callback, ?array $params = null): void {

        if (!is_callable($callback)) {

            error_log('Invalid custom signal function detected ' . var_export($callback, true)); // phpcs:ignore

        }

        self::$signalcallbacks[] = [$callback, $params ?? []];

    }

    /**

     * Register custom shutdown function.

     *

     * @param callable $callback

     * @param array $params

     * @return void

     */

    public static function register_function($callback, ?array $params = null): void {

        if (!is_callable($callback)) {

            error_log('Invalid custom shutdown function detected '.var_export($callback, true)); // phpcs:ignore

        }

        self::$callbacks[] = [$callback, $params ? array_values($params) : []];

    }

    /**

     * @private - do NOT call directly.

     */

    public static function shutdown_handler() {

        global $DB;

        // In case we caught an out of memory shutdown we increase memory limit to unlimited, so we can gracefully shut down.

        raise_memory_limit(MEMORY_UNLIMITED);

        // Always ensure we know who the user is in access logs even if they

        // were logged in a weird way midway through the request.

        set_access_log_user();

        // Custom stuff first.

        foreach (self::$callbacks as $data) {

            list($callback, $params) = $data;

            try {

                call_user_func_array($callback, $params);

            } catch (Throwable $e) {

                // phpcs:ignore

                error_log('Exception ignored in shutdown function '.get_callable_name($callback).': '.$e->getMessage());

            }

        }

        // Handle DB transactions, session need to be written afterwards

        // in order to maintain consistency in all session handlers.

        if ($DB->is_transaction_started()) {

            if (!defined('PHPUNIT_TEST') or !PHPUNIT_TEST) {

                // This should not happen, it usually indicates wrong catching of exceptions,

                // because all transactions should be finished manually or in default exception handler.

                $backtrace = $DB->get_transaction_start_backtrace();

                error_log('Potential coding error - active database transaction detected during request shutdown:'."\n".format_backtrace($backtrace, true));

            }

            $DB->force_transaction_rollback();

        }

        // Close sessions - do it here to make it consistent for all session handlers.

        \core\session\manager::write_close();

        // Other cleanup.

        self::request_shutdown();

        // Stop profiling.

        if (function_exists('profiling_is_running')) {

            if (profiling_is_running()) {

                profiling_stop();

            }

        }

        // NOTE: do not dispose $DB and MUC here, they might be used from legacy shutdown functions.

    }

    /**

     * Standard shutdown sequence.

     */

    protected static function request_shutdown() {

        global $CFG, $OUTPUT, $PERF;

        // Help apache server if possible.

        $apachereleasemem = false;

        if (function_exists('apache_child_terminate') && function_exists('memory_get_usage') && ini_get_bool('child_terminate')) {

            $limit = (empty($CFG->apachemaxmem) ? 64*1024*1024 : $CFG->apachemaxmem); // 64MB default.

            if (memory_get_usage() > get_real_size($limit)) {

                $apachereleasemem = $limit;

                @apache_child_terminate();

            }

        }

        // Deal with perf logging.

        if (MDL_PERF || (!empty($CFG->perfdebug) && $CFG->perfdebug > 7)) {

            if ($apachereleasemem) {

                error_log('Mem usage over '.$apachereleasemem.': marking Apache child for reaping.');

            }

            if (MDL_PERFTOLOG) {

                $perf = get_performance_info();

                error_log("PERF: " . $perf['txt']);

            }

            if (!empty($PERF->perfdebugdeferred)) {

                $perf = get_performance_info();

                echo $OUTPUT->select_element_for_replace('#perfdebugfooter', $perf['html']);

            }

            if (MDL_PERFINC) {

                $inc = get_included_files();

                $ts  = 0;

                foreach ($inc as $f) {

                    if (preg_match(':^/:', $f)) {

                        $fs = filesize($f);

                        $ts += $fs;

                        $hfs = display_size($fs);

                        error_log(substr($f, strlen($CFG->dirroot)) . " size: $fs ($hfs)");

                    } else {

                        error_log($f);

                    }

                }

                if ($ts > 0 ) {

                    $hts = display_size($ts);

                    error_log("Total size of files included: $ts ($hts)");

                }

            }

        }

        // Close the current streaming element if any.

        if ($OUTPUT->has_started()) {

            echo $OUTPUT->close_element_for_append();

        }

        // Print any closing buffered tags.

        if (!empty($CFG->closingtags)) {

            echo $CFG->closingtags;

        }

    }

}