[Summary view] [Print] [Text view]

   1  <?php
   2  
   3  /**
   4   * @file
   5   * The "Update status" module checks for available updates of Drupal core and
   6   * any installed contributed modules and themes. It warns site administrators
   7   * if newer releases are available via the system status report
   8   * (admin/reports/status), the module and theme pages, and optionally via email.
   9   */
  10  
  11  /**
  12   * URL to check for updates, if a given project doesn't define its own.
  13   */
  14  define('UPDATE_DEFAULT_URL', 'http://updates.drupal.org/release-history');
  15  
  16  // These are internally used constants for this code, do not modify.
  17  
  18  /**
  19   * Project is missing security update(s).
  20   */
  21  define('UPDATE_NOT_SECURE', 1);
  22  
  23  /**
  24   * Current release has been unpublished and is no longer available.
  25   */
  26  define('UPDATE_REVOKED', 2);
  27  
  28  /**
  29   * Current release is no longer supported by the project maintainer.
  30   */
  31  define('UPDATE_NOT_SUPPORTED', 3);
  32  
  33  /**
  34   * Project has a new release available, but it is not a security release.
  35   */
  36  define('UPDATE_NOT_CURRENT', 4);
  37  
  38  /**
  39   * Project is up to date.
  40   */
  41  define('UPDATE_CURRENT', 5);
  42  
  43  /**
  44   * Project's status cannot be checked.
  45   */
  46  define('UPDATE_NOT_CHECKED', -1);
  47  
  48  /**
  49   * No available update data was found for project.
  50   */
  51  define('UPDATE_UNKNOWN', -2);
  52  
  53  /**
  54   * There was a failure fetching available update data for this project.
  55   */
  56  define('UPDATE_NOT_FETCHED', -3);
  57  
  58  /**
  59   * Maximum number of attempts to fetch available update data from a given host.
  60   */
  61  define('UPDATE_MAX_FETCH_ATTEMPTS', 2);
  62  
  63  /**
  64   * Implementation of hook_help().
  65   */
  66  function update_help($path, $arg) {
  67    switch ($path) {
  68      case 'admin/reports/updates':
  69        $output = '<p>'. t('Here you can find information about available updates for your installed modules and themes. Note that each module or theme is part of a "project", which may or may not have the same name, and might include multiple modules or themes within it.') .'</p>';
  70        $output .= '<p>'. t('To extend the functionality or to change the look of your site, a number of contributed <a href="@modules">modules</a> and <a href="@themes">themes</a> are available.', array('@modules' => 'http://drupal.org/project/modules', '@themes' => 'http://drupal.org/project/themes')) .'</p>';
  71        return $output;
  72      case 'admin/build/themes':
  73      case 'admin/build/modules':
  74        include_once  './includes/install.inc';
  75        $status = update_requirements('runtime');
  76        foreach (array('core', 'contrib') as $report_type) {
  77          $type = 'update_'. $report_type;
  78          if (isset($status[$type]['severity'])) {
  79            if ($status[$type]['severity'] == REQUIREMENT_ERROR) {
  80              drupal_set_message($status[$type]['description'], 'error');
  81            }
  82            elseif ($status[$type]['severity'] == REQUIREMENT_WARNING) {
  83              drupal_set_message($status[$type]['description'], 'warning');
  84            }
  85          }
  86        }
  87        return '<p>'. t('See the <a href="@available_updates">available updates</a> page for information on installed modules and themes with new versions released.', array('@available_updates' => url('admin/reports/updates'))) .'</p>';
  88  
  89      case 'admin/reports/updates/settings':
  90      case 'admin/reports/status':
  91        // These two pages don't need additional nagging.
  92        break;
  93  
  94      case 'admin/help#update':
  95        $output = '<p>'. t("The Update status module periodically checks for new versions of your site's software (including contributed modules and themes), and alerts you to available updates.") .'</p>';
  96        $output .= '<p>'. t('The <a href="@update-report">report of available updates</a> will alert you when new releases are available for download. You may configure options for update checking frequency and notifications at the <a href="@update-settings">Update status module settings page</a>.', array('@update-report' => url('admin/reports/updates'), '@update-settings' => url('admin/reports/updates/settings'))) .'</p>';
  97        $output .= '<p>'. t('Please note that in order to provide this information, anonymous usage statistics are sent to drupal.org. If desired, you may disable the Update status module from the <a href="@modules">module administration page</a>.', array('@modules' => url('admin/build/modules'))) .'</p>';
  98        $output .= '<p>'. t('For more information, see the online handbook entry for <a href="@update">Update status module</a>.', array('@update' => 'http://drupal.org/handbook/modules/update')) .'</p>';
  99        return $output;
 100  
 101      default:
 102        // Otherwise, if we're on *any* admin page and there's a security
 103        // update missing, print an error message about it.
 104        if (arg(0) == 'admin' && strpos($path, '#') === FALSE
 105            && user_access('administer site configuration')) {
 106          include_once  './includes/install.inc';
 107          $status = update_requirements('runtime');
 108          foreach (array('core', 'contrib') as $report_type) {
 109            $type = 'update_'. $report_type;
 110            if (isset($status[$type])
 111                && isset($status[$type]['reason'])
 112                && $status[$type]['reason'] === UPDATE_NOT_SECURE) {
 113              drupal_set_message($status[$type]['description'], 'error');
 114            }
 115          }
 116        }
 117  
 118    }
 119  }
 120  
 121  /**
 122   * Implementation of hook_menu().
 123   */
 124  function update_menu() {
 125    $items = array();
 126  
 127    $items['admin/reports/updates'] = array(
 128      'title' => 'Available updates',
 129      'description' => 'Get a status report about available updates for your installed modules and themes.',
 130      'page callback' => 'update_status',
 131      'access arguments' => array('administer site configuration'),
 132      'file' => 'update.report.inc',
 133      'weight' => 10,
 134    );
 135    $items['admin/reports/updates/list'] = array(
 136      'title' => 'List',
 137      'page callback' => 'update_status',
 138      'access arguments' => array('administer site configuration'),
 139      'file' => 'update.report.inc',
 140      'type' => MENU_DEFAULT_LOCAL_TASK,
 141    );
 142    $items['admin/reports/updates/settings'] = array(
 143      'title' => 'Settings',
 144      'page callback' => 'drupal_get_form',
 145      'page arguments' => array('update_settings'),
 146      'access arguments' => array('administer site configuration'),
 147      'file' => 'update.settings.inc',
 148      'type' => MENU_LOCAL_TASK,
 149    );
 150    $items['admin/reports/updates/check'] = array(
 151      'title' => 'Manual update check',
 152      'page callback' => 'update_manual_status',
 153      'access arguments' => array('administer site configuration'),
 154      'file' => 'update.fetch.inc',
 155      'type' => MENU_CALLBACK,
 156    );
 157  
 158    return $items;
 159  }
 160  
 161  /**
 162   * Implementation of the hook_theme() registry.
 163   */
 164  function update_theme() {
 165    return array(
 166      'update_settings' => array(
 167        'arguments' => array('form' => NULL),
 168      ),
 169      'update_report' => array(
 170        'arguments' => array('data' => NULL),
 171      ),
 172      'update_version' => array(
 173        'arguments' => array('version' => NULL, 'tag' => NULL, 'class' => NULL),
 174      ),
 175    );
 176  }
 177  
 178  /**
 179   * Implementation of hook_requirements().
 180   *
 181   * @return
 182   *   An array describing the status of the site regarding available updates.
 183   *   If there is no update data, only one record will be returned, indicating
 184   *   that the status of core can't be determined. If data is available, there
 185   *   will be two records: one for core, and another for all of contrib
 186   *   (assuming there are any contributed modules or themes enabled on the
 187   *   site). In addition to the fields expected by hook_requirements ('value',
 188   *   'severity', and optionally 'description'), this array will contain a
 189   *   'reason' attribute, which is an integer constant to indicate why the
 190   *   given status is being returned (UPDATE_NOT_SECURE, UPDATE_NOT_CURRENT, or
 191   *   UPDATE_UNKNOWN). This is used for generating the appropriate e-mail
 192   *   notification messages during update_cron(), and might be useful for other
 193   *   modules that invoke update_requirements() to find out if the site is up
 194   *   to date or not.
 195   *
 196   * @see _update_message_text()
 197   * @see _update_cron_notify()
 198   */
 199  function update_requirements($phase) {
 200    if ($phase == 'runtime') {
 201      if ($available = update_get_available(FALSE)) {
 202        module_load_include('inc', 'update', 'update.compare');
 203        $data = update_calculate_project_data($available);
 204        // First, populate the requirements for core:
 205        $requirements['update_core'] = _update_requirement_check($data['drupal'], 'core');
 206        // We don't want to check drupal a second time.
 207        unset($data['drupal']);
 208        if (!empty($data)) {
 209          // Now, sort our $data array based on each project's status. The
 210          // status constants are numbered in the right order of precedence, so
 211          // we just need to make sure the projects are sorted in ascending
 212          // order of status, and we can look at the first project we find.
 213          uasort($data, '_update_project_status_sort');
 214          $first_project = reset($data);
 215          $requirements['update_contrib'] = _update_requirement_check($first_project, 'contrib');
 216        }
 217      }
 218      else {
 219        $requirements['update_core']['title'] = t('Drupal core update status');
 220        $requirements['update_core']['value'] = t('No update data available');
 221        $requirements['update_core']['severity'] = REQUIREMENT_WARNING;
 222        $requirements['update_core']['reason'] = UPDATE_UNKNOWN;
 223        $requirements['update_core']['description'] = _update_no_data();
 224      }
 225      return $requirements;
 226    }
 227  }
 228  
 229  /**
 230   * Private helper method to fill in the requirements array.
 231   *
 232   * This is shared for both core and contrib to generate the right elements in
 233   * the array for hook_requirements().
 234   *
 235   * @param $project
 236   *  Array of information about the project we're testing as returned by
 237   *  update_calculate_project_data().
 238   * @param $type
 239   *  What kind of project is this ('core' or 'contrib').
 240   *
 241   * @return
 242   *  An array to be included in the nested $requirements array.
 243   *
 244   * @see hook_requirements()
 245   * @see update_requirements()
 246   * @see update_calculate_project_data()
 247   */
 248  function _update_requirement_check($project, $type) {
 249    $requirement = array();
 250    if ($type == 'core') {
 251      $requirement['title'] = t('Drupal core update status');
 252    }
 253    else {
 254      $requirement['title'] = t('Module and theme update status');
 255    }
 256    $status = $project['status'];
 257    if ($status != UPDATE_CURRENT) {
 258      $requirement['reason'] = $status;
 259      $requirement['description'] = _update_message_text($type, $status, TRUE);
 260      $requirement['severity'] = REQUIREMENT_ERROR;
 261    }
 262    switch ($status) {
 263      case UPDATE_NOT_SECURE:
 264        $requirement_label = t('Not secure!');
 265        break;
 266      case UPDATE_REVOKED:
 267        $requirement_label = t('Revoked!');
 268        break;
 269      case UPDATE_NOT_SUPPORTED:
 270        $requirement_label = t('Unsupported release');
 271        break;
 272      case UPDATE_NOT_CURRENT:
 273        $requirement_label = t('Out of date');
 274        $requirement['severity'] = REQUIREMENT_WARNING;
 275        break;
 276      case UPDATE_UNKNOWN:
 277      case UPDATE_NOT_CHECKED:
 278      case UPDATE_NOT_FETCHED:
 279        $requirement_label = isset($project['reason']) ? $project['reason'] : t('Can not determine status');
 280        $requirement['severity'] = REQUIREMENT_WARNING;
 281        break;
 282      default:
 283        $requirement_label = t('Up to date');
 284    }
 285    if ($status != UPDATE_CURRENT && $type == 'core' && isset($project['recommended'])) {
 286      $requirement_label .= ' '. t('(version @version available)', array('@version' => $project['recommended']));
 287    }
 288    $requirement['value'] = l($requirement_label, 'admin/reports/updates');
 289    return $requirement;
 290  }
 291  
 292  /**
 293   * Implementation of hook_cron().
 294   */
 295  function update_cron() {
 296    $frequency = variable_get('update_check_frequency', 1);
 297    $interval = 60 * 60 * 24 * $frequency;
 298    // Cron should check for updates if there is no update data cached or if the
 299    // configured update interval has elapsed.
 300    if (!_update_cache_get('update_available_releases') || ((time() - variable_get('update_last_check', 0)) > $interval)) {
 301      update_refresh();
 302      _update_cron_notify();
 303    }
 304  }
 305  
 306  /**
 307   * Implementation of hook_form_alter().
 308   *
 309   * Adds a submit handler to the system modules and themes forms, so that if a
 310   * site admin saves either form, we invalidate the cache of available updates.
 311   *
 312   * @see update_invalidate_cache()
 313   */
 314  function update_form_alter(&$form, $form_state, $form_id) {
 315    if ($form_id == 'system_modules' || $form_id == 'system_themes_form' ) {
 316      $form['#submit'][] = 'update_invalidate_cache';
 317    }
 318  }
 319  
 320  /**
 321   * Prints a warning message when there is no data about available updates.
 322   */
 323  function _update_no_data() {
 324    $destination = drupal_get_destination();
 325    return t('No information is available about potential new releases for currently installed modules and themes. To check for updates, you may need to <a href="@run_cron">run cron</a> or you can <a href="@check_manually">check manually</a>. Please note that checking for available updates can take a long time, so please be patient.', array(
 326      '@run_cron' => url('admin/reports/status/run-cron', array('query' => $destination)),
 327      '@check_manually' => url('admin/reports/updates/check', array('query' => $destination)),
 328    ));
 329  }
 330  
 331  /**
 332   * Internal helper to try to get the update information from the cache
 333   * if possible, and to refresh the cache when necessary.
 334   *
 335   * In addition to checking the cache lifetime, this function also ensures that
 336   * there are no .info files for enabled modules or themes that have a newer
 337   * modification timestamp than the last time we checked for available update
 338   * data. If any .info file was modified, it almost certainly means a new
 339   * version of something was installed. Without fresh available update data,
 340   * the logic in update_calculate_project_data() will be wrong and produce
 341   * confusing, bogus results.
 342   *
 343   * @param $refresh
 344   *   Boolean to indicate if this method should refresh the cache automatically
 345   *   if there's no data.
 346   *
 347   * @see update_refresh()
 348   * @see update_get_projects()
 349   */
 350  function update_get_available($refresh = FALSE) {
 351    module_load_include('inc', 'update', 'update.compare');
 352    $available = array();
 353  
 354    // First, make sure that none of the .info files have a change time
 355    // newer than the last time we checked for available updates.
 356    $needs_refresh = FALSE;
 357    $last_check = variable_get('update_last_check', 0);
 358    $projects = update_get_projects();
 359    foreach ($projects as $key => $project) {
 360      if ($project['info']['_info_file_ctime'] > $last_check) {
 361        $needs_refresh = TRUE;
 362        break;
 363      }
 364    }
 365    if (!$needs_refresh && ($cache = _update_cache_get('update_available_releases')) && $cache->expire > time()) {
 366      $available = $cache->data;
 367    }
 368    elseif ($needs_refresh || $refresh) {
 369      // If we need to refresh due to a newer .info file, ignore the argument
 370      // and force the refresh (e.g., even for update_requirements()) to prevent
 371      // bogus results.
 372      $available = update_refresh();
 373    }
 374    return $available;
 375  }
 376  
 377  /**
 378   * Wrapper to load the include file and then refresh the release data.
 379   */
 380  function update_refresh() {
 381    module_load_include('inc', 'update', 'update.fetch');
 382    return _update_refresh();
 383  }
 384  
 385  /**
 386   * Implementation of hook_mail().
 387   *
 388   * Constructs the email notification message when the site is out of date.
 389   *
 390   * @param $key
 391   *   Unique key to indicate what message to build, always 'status_notify'.
 392   * @param $message
 393   *   Reference to the message array being built.
 394   * @param $params
 395   *   Array of parameters to indicate what kind of text to include in the
 396   *   message body. This is a keyed array of message type ('core' or 'contrib')
 397   *   as the keys, and the status reason constant (UPDATE_NOT_SECURE, etc) for
 398   *   the values.
 399   *
 400   * @see drupal_mail()
 401   * @see _update_cron_notify()
 402   * @see _update_message_text()
 403   */
 404  function update_mail($key, &$message, $params) {
 405    $language = $message['language'];
 406    $langcode = $language->language;
 407    $message['subject'] .= t('New release(s) available for !site_name', array('!site_name' => variable_get('site_name', 'Drupal')), $langcode);
 408    foreach ($params as $msg_type => $msg_reason) {
 409      $message['body'][] = _update_message_text($msg_type, $msg_reason, FALSE, $language);
 410    }
 411    $message['body'][] = t('See the available updates page for more information:', array(), $langcode) ."\n". url('admin/reports/updates', array('absolute' => TRUE, 'language' => $language));
 412  }
 413  
 414  /**
 415   * Helper function to return the appropriate message text when the site is out
 416   * of date or missing a security update.
 417   *
 418   * These error messages are shared by both update_requirements() for the
 419   * site-wide status report at admin/reports/status and in the body of the
 420   * notification emails generated by update_cron().
 421   *
 422   * @param $msg_type
 423   *   String to indicate what kind of message to generate. Can be either
 424   *   'core' or 'contrib'.
 425   * @param $msg_reason
 426   *   Integer constant specifying why message is generated.
 427   * @param $report_link
 428   *   Boolean that controls if a link to the updates report should be added.
 429   * @param $language
 430   *   An optional language object to use.
 431   * @return
 432   *   The properly translated error message for the given key.
 433   */
 434  function _update_message_text($msg_type, $msg_reason, $report_link = FALSE, $language = NULL) {
 435    $langcode = isset($language) ? $language->language : NULL;
 436    $text = '';
 437    switch ($msg_reason) {
 438      case UPDATE_NOT_SECURE:
 439        if ($msg_type == 'core') {
 440          $text = t('There is a security update available for your version of Drupal. To ensure the security of your server, you should update immediately!', array(), $langcode);
 441        }
 442        else {
 443          $text = t('There are security updates available for one or more of your modules or themes. To ensure the security of your server, you should update immediately!', array(), $langcode);
 444        }
 445        break;
 446  
 447      case UPDATE_REVOKED:
 448        if ($msg_type == 'core') {
 449          $text = t('Your version of Drupal has been revoked and is no longer available for download. Upgrading is strongly recommended!', array(), $langcode);
 450        }
 451        else {
 452          $text = t('The installed version of at least one of your modules or themes has been revoked and is no longer available for download. Upgrading or disabling is strongly recommended!', array(), $langcode);
 453        }
 454        break;
 455  
 456      case UPDATE_NOT_SUPPORTED:
 457        if ($msg_type == 'core') {
 458          $text = t('Your version of Drupal is no longer supported. Upgrading is strongly recommended!', array(), $langcode);
 459        }
 460        else {
 461          $text = t('The installed version of at least one of your modules or themes is no longer supported. Upgrading or disabling is strongly recommended! Please see the project homepage for more details.', array(), $langcode);
 462        }
 463        break;
 464  
 465      case UPDATE_NOT_CURRENT:
 466        if ($msg_type == 'core') {
 467          $text = t('There are updates available for your version of Drupal. To ensure the proper functioning of your site, you should update as soon as possible.', array(), $langcode);
 468        }
 469        else {
 470          $text = t('There are updates available for one or more of your modules or themes. To ensure the proper functioning of your site, you should update as soon as possible.', array(), $langcode);
 471        }
 472        break;
 473  
 474      case UPDATE_UNKNOWN:
 475      case UPDATE_NOT_CHECKED:
 476      case UPDATE_NOT_FETCHED:
 477        if ($msg_type == 'core') {
 478          $text = t('There was a problem determining the status of available updates for your version of Drupal.', array(), $langcode);
 479        }
 480        else {
 481          $text = t('There was a problem determining the status of available updates for one or more of your modules or themes.', array(), $langcode);
 482        }
 483        break;
 484    }
 485  
 486    if ($report_link) {
 487      $text .= ' '. t('See the <a href="@available_updates">available updates</a> page for more information.', array('@available_updates' => url('admin/reports/updates', array('language' => $language))), $langcode);
 488    }
 489  
 490    return $text;
 491  }
 492  
 493  /**
 494   * Private sort function to order projects based on their status.
 495   *
 496   * @see update_requirements()
 497   * @see uasort()
 498   */
 499  function _update_project_status_sort($a, $b) {
 500    // The status constants are numerically in the right order, so we can
 501    // usually subtract the two to compare in the order we want. However,
 502    // negative status values should be treated as if they are huge, since we
 503    // always want them at the bottom of the list.
 504    $a_status = $a['status'] > 0 ? $a['status'] : (-10 * $a['status']);
 505    $b_status = $b['status'] > 0 ? $b['status'] : (-10 * $b['status']);
 506    return $a_status - $b_status;
 507  }
 508  
 509  /**
 510   * @defgroup update_status_cache Private update status cache system
 511   * @{
 512   *
 513   * We specifically do NOT use the core cache API for saving the fetched data
 514   * about available updates. It is vitally important that this cache is only
 515   * cleared when we're populating it after successfully fetching new available
 516   * update data. Usage of the core cache API results in all sorts of potential
 517   * problems that would result in attempting to fetch available update data all
 518   * the time, including if a site has a "minimum cache lifetime" (which is both
 519   * a minimum and a maximum) defined, or if a site uses memcache or another
 520   * plug-able cache system that assumes volatile caches.
 521   *
 522   * Update module still uses the {cache_update} table, but instead of using
 523   * cache_set(), cache_get(), and cache_clear_all(), there are private helper
 524   * functions that implement these same basic tasks but ensure that the cache
 525   * is not prematurely cleared, and that the data is always stored in the
 526   * database, even if memcache or another cache backend is in use.
 527   */
 528  
 529  /**
 530   * Store data in the private update status cache table.
 531   *
 532   * Note: this function completely ignores the {cache_update}.headers field
 533   * since that is meaningless for the kinds of data we're caching.
 534   *
 535   * @param $cid
 536   *   The cache ID to save the data with.
 537   * @param $data
 538   *   The data to store.
 539   * @param $expire
 540   *   One of the following values:
 541   *   - CACHE_PERMANENT: Indicates that the item should never be removed except
 542   *     by explicitly using _update_cache_clear() or update_invalidate_cache().
 543   *   - A Unix timestamp: Indicates that the item should be kept at least until
 544   *     the given time, after which it will be invalidated.
 545   */
 546  function _update_cache_set($cid, $data, $expire) {
 547    $serialized = 0;
 548    if (is_object($data) || is_array($data)) {
 549      $data = serialize($data);
 550      $serialized = 1;
 551    }
 552    $created = time();
 553    db_query("UPDATE {cache_update} SET data = %b, created = %d, expire = %d, serialized = %d WHERE cid = '%s'", $data, $created, $expire, $serialized, $cid);
 554    if (!db_affected_rows()) {
 555      @db_query("INSERT INTO {cache_update} (cid, data, created, expire, serialized) VALUES ('%s', %b, %d, %d, %d)", $cid, $data, $created, $expire, $serialized);
 556    }
 557  }
 558  
 559  /**
 560   * Retrieve data from the private update status cache table.
 561   *
 562   * @param $cid
 563   *   The cache ID to retrieve.
 564   * @return
 565   *   The data for the given cache ID, or NULL if the ID was not found.
 566   */
 567  function _update_cache_get($cid) {
 568    $cache = db_fetch_object(db_query("SELECT data, created, expire, serialized FROM {cache_update} WHERE cid = '%s'", $cid));
 569    if (isset($cache->data)) {
 570      $cache->data = db_decode_blob($cache->data);
 571      if ($cache->serialized) {
 572        $cache->data = unserialize($cache->data);
 573      }
 574    }
 575    return $cache;
 576  }
 577  
 578  /**
 579   * Invalidates specific cached data relating to update status.
 580   *
 581   * @param $cid
 582   *   Optional cache ID of the record to clear from the private update module
 583   *   cache. If empty, all records will be cleared from the table.
 584   */
 585  function _update_cache_clear($cid = NULL) {
 586    if (empty($cid)) {
 587      db_query("TRUNCATE TABLE {cache_update}");
 588    }
 589    else {
 590      db_query("DELETE FROM {cache_update} WHERE cid = '%s'", $cid);
 591    }
 592  }
 593  
 594  /**
 595   * Implementation of hook_flush_caches().
 596   *
 597   * Called from update.php (among others) to flush the caches.
 598   * Since we're running update.php, we are likely to install a new version of
 599   * something, in which case, we want to check for available update data again.
 600   * However, because we have our own caching system, we need to directly clear
 601   * the database table ourselves at this point and return nothing, for example,
 602   * on sites that use memcache where cache_clear_all() won't know how to purge
 603   * this data.
 604   *
 605   * However, we only want to do this from update.php, since otherwise, we'd
 606   * lose all the available update data on every cron run. So, we specifically
 607   * check if the site is in MAINTENANCE_MODE == 'update' (which indicates
 608   * update.php is running, not update module... alas for overloaded names).
 609   */
 610  function update_flush_caches() {
 611    if (defined('MAINTENANCE_MODE') && MAINTENANCE_MODE == 'update') {
 612      _update_cache_clear();
 613    }
 614    return array();
 615  }
 616  
 617  /**
 618   * Invalidates all cached data relating to update status.
 619   */
 620  function update_invalidate_cache() {
 621    _update_cache_clear();
 622  }
 623  
 624  /**
 625   * @} End of "defgroup update_status_cache".
 626   */