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Differences Between: [Versions 310 and 401] [Versions 311 and 401] [Versions 39 and 401] [Versions 401 and 403]

   1  <?php
   2  // This file is part of Moodle - http://moodle.org/
   3  //
   4  // Moodle is free software: you can redistribute it and/or modify
   5  // it under the terms of the GNU General Public License as published by
   6  // the Free Software Foundation, either version 3 of the License, or
   7  // (at your option) any later version.
   8  //
   9  // Moodle is distributed in the hope that it will be useful,
  10  // but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  // GNU General Public License for more details.
  13  //
  14  // You should have received a copy of the GNU General Public License
  15  // along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
  16  
  17  /**
  18   * Shutdown management class.
  19   *
  20   * @package    core
  21   * @copyright  2013 Petr Skoda {@link http://skodak.org}
  22   * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  23   */
  24  
  25  defined('MOODLE_INTERNAL') || die();
  26  
  27  /**
  28   * Shutdown management class.
  29   *
  30   * @package    core
  31   * @copyright  2013 Petr Skoda {@link http://skodak.org}
  32   * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  33   */
  34  class core_shutdown_manager {
  35      /** @var array list of custom callbacks */
  36      protected static $callbacks = [];
  37      /** @var array list of custom signal callbacks */
  38      protected static $signalcallbacks = [];
  39      /** @var bool is this manager already registered? */
  40      protected static $registered = false;
  41  
  42      /**
  43       * Register self as main shutdown handler.
  44       *
  45       * @private to be called from lib/setup.php only!
  46       */
  47      public static function initialize() {
  48          if (self::$registered) {
  49              debugging('Shutdown manager is already initialised!');
  50          }
  51          self::$registered = true;
  52          register_shutdown_function(array('core_shutdown_manager', 'shutdown_handler'));
  53  
  54          // Signal handlers should only be used when dealing with a CLI script.
  55          // In the case of PHP called in a web server the server is the owning process and should handle the signal chain
  56          // properly itself.
  57          // The 'pcntl' extension is optional and not available on Windows.
  58          if (CLI_SCRIPT && extension_loaded('pcntl') && function_exists('pcntl_async_signals')) {
  59              // We capture and handle SIGINT (Ctrl+C) and SIGTERM (termination requested).
  60              pcntl_async_signals(true);
  61              pcntl_signal(SIGINT, ['core_shutdown_manager', 'signal_handler']);
  62              pcntl_signal(SIGTERM, ['core_shutdown_manager', 'signal_handler']);
  63          }
  64      }
  65  
  66      /**
  67       * Signal handler for SIGINT, and SIGTERM.
  68       *
  69       * @param   int     $signo The signal being handled
  70       */
  71      public static function signal_handler(int $signo) {
  72          // Note: There is no need to manually call the shutdown handler.
  73          // The fact that we are calling exit() in this script means that the standard shutdown handling is performed
  74          // anyway.
  75          switch ($signo) {
  76              case SIGTERM:
  77                  // Replicate native behaviour.
  78                  echo "Terminated: {$signo}\n";
  79  
  80                  // The standard exit code for SIGTERM is 143.
  81                  $exitcode = 143;
  82                  break;
  83              case SIGINT:
  84                  // Replicate native behaviour.
  85                  echo "\n";
  86  
  87                  // The standard exit code for SIGINT (Ctrl+C) is 130.
  88                  $exitcode = 130;
  89                  break;
  90              default:
  91                  // The signal handler was called with a signal it was not expecting.
  92                  // We should exit and complain.
  93                  echo "Warning: \core_shutdown_manager::signal_handler() was called with an unexpected signal ({$signo}).\n";
  94                  $exitcode = 1;
  95          }
  96  
  97          // Normally we should exit unless a callback tells us to wait.
  98          $shouldexit = true;
  99          foreach (self::$signalcallbacks as $data) {
 100              list($callback, $params) = $data;
 101              try {
 102                  array_unshift($params, $signo);
 103                  $shouldexit = call_user_func_array($callback, $params) && $shouldexit;
 104              } catch (Throwable $e) {
 105                  // phpcs:ignore
 106                  error_log('Exception ignored in signal function ' . get_callable_name($callback) . ': ' . $e->getMessage());
 107              }
 108          }
 109  
 110          if ($shouldexit) {
 111              exit ($exitcode);
 112          }
 113      }
 114  
 115      /**
 116       * Register custom signal handler function.
 117       *
 118       * If a handler returns false the signal will be ignored.
 119       *
 120       * @param callable $callback
 121       * @param array $params
 122       * @return void
 123       */
 124      public static function register_signal_handler($callback, array $params = null): void {
 125          if (!is_callable($callback)) {
 126              error_log('Invalid custom signal function detected ' . var_export($callback, true)); // phpcs:ignore
 127          }
 128          self::$signalcallbacks[] = [$callback, $params ?? []];
 129      }
 130  
 131      /**
 132       * Register custom shutdown function.
 133       *
 134       * @param callable $callback
 135       * @param array $params
 136       * @return void
 137       */
 138      public static function register_function($callback, array $params = null): void {
 139          if (!is_callable($callback)) {
 140              error_log('Invalid custom shutdown function detected '.var_export($callback, true)); // phpcs:ignore
 141          }
 142          self::$callbacks[] = [$callback, $params ? array_values($params) : []];
 143      }
 144  
 145      /**
 146       * @private - do NOT call directly.
 147       */
 148      public static function shutdown_handler() {
 149          global $DB;
 150  
 151          // Always ensure we know who the user is in access logs even if they
 152          // were logged in a weird way midway through the request.
 153          set_access_log_user();
 154  
 155          // Custom stuff first.
 156          foreach (self::$callbacks as $data) {
 157              list($callback, $params) = $data;
 158              try {
 159                  call_user_func_array($callback, $params);
 160              } catch (Throwable $e) {
 161                  // phpcs:ignore
 162                  error_log('Exception ignored in shutdown function '.get_callable_name($callback).': '.$e->getMessage());
 163              }
 164          }
 165  
 166          // Handle DB transactions, session need to be written afterwards
 167          // in order to maintain consistency in all session handlers.
 168          if ($DB->is_transaction_started()) {
 169              if (!defined('PHPUNIT_TEST') or !PHPUNIT_TEST) {
 170                  // This should not happen, it usually indicates wrong catching of exceptions,
 171                  // because all transactions should be finished manually or in default exception handler.
 172                  $backtrace = $DB->get_transaction_start_backtrace();
 173                  error_log('Potential coding error - active database transaction detected during request shutdown:'."\n".format_backtrace($backtrace, true));
 174              }
 175              $DB->force_transaction_rollback();
 176          }
 177  
 178          // Close sessions - do it here to make it consistent for all session handlers.
 179          \core\session\manager::write_close();
 180  
 181          // Other cleanup.
 182          self::request_shutdown();
 183  
 184          // Stop profiling.
 185          if (function_exists('profiling_is_running')) {
 186              if (profiling_is_running()) {
 187                  profiling_stop();
 188              }
 189          }
 190  
 191          // NOTE: do not dispose $DB and MUC here, they might be used from legacy shutdown functions.
 192      }
 193  
 194      /**
 195       * Standard shutdown sequence.
 196       */
 197      protected static function request_shutdown() {
 198          global $CFG;
 199  
 200          // Help apache server if possible.
 201          $apachereleasemem = false;
 202          if (function_exists('apache_child_terminate') && function_exists('memory_get_usage') && ini_get_bool('child_terminate')) {
 203              $limit = (empty($CFG->apachemaxmem) ? 64*1024*1024 : $CFG->apachemaxmem); // 64MB default.
 204              if (memory_get_usage() > get_real_size($limit)) {
 205                  $apachereleasemem = $limit;
 206                  @apache_child_terminate();
 207              }
 208          }
 209  
 210          // Deal with perf logging.
 211          if ((defined('MDL_PERF') && MDL_PERF) || (!empty($CFG->perfdebug) && $CFG->perfdebug > 7)) {
 212              if ($apachereleasemem) {
 213                  error_log('Mem usage over '.$apachereleasemem.': marking Apache child for reaping.');
 214              }
 215              if (defined('MDL_PERFTOLOG') && MDL_PERFTOLOG) {
 216                  $perf = get_performance_info();
 217                  error_log("PERF: " . $perf['txt']);
 218              }
 219              if (defined('MDL_PERFINC') && MDL_PERFINC) {
 220                  $inc = get_included_files();
 221                  $ts  = 0;
 222                  foreach ($inc as $f) {
 223                      if (preg_match(':^/:', $f)) {
 224                          $fs = filesize($f);
 225                          $ts += $fs;
 226                          $hfs = display_size($fs);
 227                          error_log(substr($f, strlen($CFG->dirroot)) . " size: $fs ($hfs)", null, null, 0);
 228                      } else {
 229                          error_log($f , null, null, 0);
 230                      }
 231                  }
 232                  if ($ts > 0 ) {
 233                      $hts = display_size($ts);
 234                      error_log("Total size of files included: $ts ($hts)");
 235                  }
 236              }
 237          }
 238      }
 239  }