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   1  <?php
   2  // $Id: update.module,v 1.17.2.6 2009/12/16 17:30:00 goba Exp $
   3  
   4  /**
   5   * @file
   6   * The "Update status" module checks for available updates of Drupal core and
   7   * any installed contributed modules and themes. It warns site administrators
   8   * if newer releases are available via the system status report
   9   * (admin/reports/status), the module and theme pages, and optionally via email.
  10   */
  11  
  12  /**
  13   * URL to check for updates, if a given project doesn't define its own.
  14   */
  15  define('UPDATE_DEFAULT_URL', 'http://updates.drupal.org/release-history');
  16  
  17  // These are internally used constants for this code, do not modify.
  18  
  19  /**
  20   * Project is missing security update(s).
  21   */
  22  define('UPDATE_NOT_SECURE', 1);
  23  
  24  /**
  25   * Current release has been unpublished and is no longer available.
  26   */
  27  define('UPDATE_REVOKED', 2);
  28  
  29  /**
  30   * Current release is no longer supported by the project maintainer.
  31   */
  32  define('UPDATE_NOT_SUPPORTED', 3);
  33  
  34  /**
  35   * Project has a new release available, but it is not a security release.
  36   */
  37  define('UPDATE_NOT_CURRENT', 4);
  38  
  39  /**
  40   * Project is up to date.
  41   */
  42  define('UPDATE_CURRENT', 5);
  43  
  44  /**
  45   * Project's status cannot be checked.
  46   */
  47  define('UPDATE_NOT_CHECKED', -1);
  48  
  49  /**
  50   * No available update data was found for project.
  51   */
  52  define('UPDATE_UNKNOWN', -2);
  53  
  54  /**
  55   * There was a failure fetching available update data for this project.
  56   */
  57  define('UPDATE_NOT_FETCHED', -3);
  58  
  59  /**
  60   * Maximum number of attempts to fetch available update data from a given host.
  61   */
  62  define('UPDATE_MAX_FETCH_ATTEMPTS', 2);
  63  
  64  /**
  65   * Implementation of hook_help().
  66   */
  67  function update_help($path, $arg) {
  68    switch ($path) {
  69      case 'admin/reports/updates':
  70        $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>';
  71        $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>';
  72        return $output;
  73      case 'admin/build/themes':
  74      case 'admin/build/modules':
  75        include_once  './includes/install.inc';
  76        $status = update_requirements('runtime');
  77        foreach (array('core', 'contrib') as $report_type) {
  78          $type = 'update_'. $report_type;
  79          if (isset($status[$type]['severity'])) {
  80            if ($status[$type]['severity'] == REQUIREMENT_ERROR) {
  81              drupal_set_message($status[$type]['description'], 'error');
  82            }
  83            elseif ($status[$type]['severity'] == REQUIREMENT_WARNING) {
  84              drupal_set_message($status[$type]['description'], 'warning');
  85            }
  86          }
  87        }
  88        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>';
  89  
  90      case 'admin/reports/updates/settings':
  91      case 'admin/reports/status':
  92        // These two pages don't need additional nagging.
  93        break;
  94  
  95      case 'admin/help#update':
  96        $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>';
  97        $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>';
  98        $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>';
  99        $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>';
 100        return $output;
 101  
 102      default:
 103        // Otherwise, if we're on *any* admin page and there's a security
 104        // update missing, print an error message about it.
 105        if (arg(0) == 'admin' && strpos($path, '#') === FALSE
 106            && user_access('administer site configuration')) {
 107          include_once  './includes/install.inc';
 108          $status = update_requirements('runtime');
 109          foreach (array('core', 'contrib') as $report_type) {
 110            $type = 'update_'. $report_type;
 111            if (isset($status[$type])
 112                && isset($status[$type]['reason'])
 113                && $status[$type]['reason'] === UPDATE_NOT_SECURE) {
 114              drupal_set_message($status[$type]['description'], 'error');
 115            }
 116          }
 117        }
 118  
 119    }
 120  }
 121  
 122  /**
 123   * Implementation of hook_menu().
 124   */
 125  function update_menu() {
 126    $items = array();
 127  
 128    $items['admin/reports/updates'] = array(
 129      'title' => 'Available updates',
 130      'description' => 'Get a status report about available updates for your installed modules and themes.',
 131      'page callback' => 'update_status',
 132      'access arguments' => array('administer site configuration'),
 133      'file' => 'update.report.inc',
 134      'weight' => 10,
 135    );
 136    $items['admin/reports/updates/list'] = array(
 137      'title' => 'List',
 138      'page callback' => 'update_status',
 139      'access arguments' => array('administer site configuration'),
 140      'file' => 'update.report.inc',
 141      'type' => MENU_DEFAULT_LOCAL_TASK,
 142    );
 143    $items['admin/reports/updates/settings'] = array(
 144      'title' => 'Settings',
 145      'page callback' => 'drupal_get_form',
 146      'page arguments' => array('update_settings'),
 147      'access arguments' => array('administer site configuration'),
 148      'file' => 'update.settings.inc',
 149      'type' => MENU_LOCAL_TASK,
 150    );
 151    $items['admin/reports/updates/check'] = array(
 152      'title' => 'Manual update check',
 153      'page callback' => 'update_manual_status',
 154      'access arguments' => array('administer site configuration'),
 155      'file' => 'update.fetch.inc',
 156      'type' => MENU_CALLBACK,
 157    );
 158  
 159    return $items;
 160  }
 161  
 162  /**
 163   * Implementation of the hook_theme() registry.
 164   */
 165  function update_theme() {
 166    return array(
 167      'update_settings' => array(
 168        'arguments' => array('form' => NULL),
 169      ),
 170      'update_report' => array(
 171        'arguments' => array('data' => NULL),
 172      ),
 173      'update_version' => array(
 174        'arguments' => array('version' => NULL, 'tag' => NULL, 'class' => NULL),
 175      ),
 176    );
 177  }
 178  
 179  /**
 180   * Implementation of hook_requirements().
 181   *
 182   * @return
 183   *   An array describing the status of the site regarding available updates.
 184   *   If there is no update data, only one record will be returned, indicating
 185   *   that the status of core can't be determined. If data is available, there
 186   *   will be two records: one for core, and another for all of contrib
 187   *   (assuming there are any contributed modules or themes enabled on the
 188   *   site). In addition to the fields expected by hook_requirements ('value',
 189   *   'severity', and optionally 'description'), this array will contain a
 190   *   'reason' attribute, which is an integer constant to indicate why the
 191   *   given status is being returned (UPDATE_NOT_SECURE, UPDATE_NOT_CURRENT, or
 192   *   UPDATE_UNKNOWN). This is used for generating the appropriate e-mail
 193   *   notification messages during update_cron(), and might be useful for other
 194   *   modules that invoke update_requirements() to find out if the site is up
 195   *   to date or not.
 196   *
 197   * @see _update_message_text()
 198   * @see _update_cron_notify()
 199   */
 200  function update_requirements($phase) {
 201    if ($phase == 'runtime') {
 202      if ($available = update_get_available(FALSE)) {
 203        module_load_include('inc', 'update', 'update.compare');
 204        $data = update_calculate_project_data($available);
 205        // First, populate the requirements for core:
 206        $requirements['update_core'] = _update_requirement_check($data['drupal'], 'core');
 207        // We don't want to check drupal a second time.
 208        unset($data['drupal']);
 209        if (!empty($data)) {
 210          // Now, sort our $data array based on each project's status. The
 211          // status constants are numbered in the right order of precedence, so
 212          // we just need to make sure the projects are sorted in ascending
 213          // order of status, and we can look at the first project we find.
 214          uasort($data, '_update_project_status_sort');
 215          $first_project = reset($data);
 216          $requirements['update_contrib'] = _update_requirement_check($first_project, 'contrib');
 217        }
 218      }
 219      else {
 220        $requirements['update_core']['title'] = t('Drupal core update status');
 221        $requirements['update_core']['value'] = t('No update data available');
 222        $requirements['update_core']['severity'] = REQUIREMENT_WARNING;
 223        $requirements['update_core']['reason'] = UPDATE_UNKNOWN;
 224        $requirements['update_core']['description'] = _update_no_data();
 225      }
 226      return $requirements;
 227    }
 228  }
 229  
 230  /**
 231   * Private helper method to fill in the requirements array.
 232   *
 233   * This is shared for both core and contrib to generate the right elements in
 234   * the array for hook_requirements().
 235   *
 236   * @param $project
 237   *  Array of information about the project we're testing as returned by
 238   *  update_calculate_project_data().
 239   * @param $type
 240   *  What kind of project is this ('core' or 'contrib').
 241   *
 242   * @return
 243   *  An array to be included in the nested $requirements array.
 244   *
 245   * @see hook_requirements()
 246   * @see update_requirements()
 247   * @see update_calculate_project_data()
 248   */
 249  function _update_requirement_check($project, $type) {
 250    $requirement = array();
 251    if ($type == 'core') {
 252      $requirement['title'] = t('Drupal core update status');
 253    }
 254    else {
 255      $requirement['title'] = t('Module and theme update status');
 256    }
 257    $status = $project['status'];
 258    if ($status != UPDATE_CURRENT) {
 259      $requirement['reason'] = $status;
 260      $requirement['description'] = _update_message_text($type, $status, TRUE);
 261      $requirement['severity'] = REQUIREMENT_ERROR;
 262    }
 263    switch ($status) {
 264      case UPDATE_NOT_SECURE:
 265        $requirement_label = t('Not secure!');
 266        break;
 267      case UPDATE_REVOKED:
 268        $requirement_label = t('Revoked!');
 269        break;
 270      case UPDATE_NOT_SUPPORTED:
 271        $requirement_label = t('Unsupported release');
 272        break;
 273      case UPDATE_NOT_CURRENT:
 274        $requirement_label = t('Out of date');
 275        $requirement['severity'] = REQUIREMENT_WARNING;
 276        break;
 277      case UPDATE_UNKNOWN:
 278      case UPDATE_NOT_CHECKED:
 279      case UPDATE_NOT_FETCHED:
 280        $requirement_label = isset($project['reason']) ? $project['reason'] : t('Can not determine status');
 281        $requirement['severity'] = REQUIREMENT_WARNING;
 282        break;
 283      default:
 284        $requirement_label = t('Up to date');
 285    }
 286    if ($status != UPDATE_CURRENT && $type == 'core' && isset($project['recommended'])) {
 287      $requirement_label .= ' '. t('(version @version available)', array('@version' => $project['recommended']));
 288    }
 289    $requirement['value'] = l($requirement_label, 'admin/reports/updates');
 290    return $requirement;
 291  }
 292  
 293  /**
 294   * Implementation of hook_cron().
 295   */
 296  function update_cron() {
 297    $frequency = variable_get('update_check_frequency', 1);
 298    $interval = 60 * 60 * 24 * $frequency;
 299    // Cron should check for updates if there is no update data cached or if the
 300    // configured update interval has elapsed.
 301    if (!_update_cache_get('update_available_releases') || ((time() - variable_get('update_last_check', 0)) > $interval)) {
 302      update_refresh();
 303      _update_cron_notify();
 304    }
 305  }
 306  
 307  /**
 308   * Implementation of hook_form_alter().
 309   *
 310   * Adds a submit handler to the system modules and themes forms, so that if a
 311   * site admin saves either form, we invalidate the cache of available updates.
 312   *
 313   * @see update_invalidate_cache()
 314   */
 315  function update_form_alter(&$form, $form_state, $form_id) {
 316    if ($form_id == 'system_modules' || $form_id == 'system_themes_form' ) {
 317      $form['#submit'][] = 'update_invalidate_cache';
 318    }
 319  }
 320  
 321  /**
 322   * Prints a warning message when there is no data about available updates.
 323   */
 324  function _update_no_data() {
 325    $destination = drupal_get_destination();
 326    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(
 327      '@run_cron' => url('admin/reports/status/run-cron', array('query' => $destination)),
 328      '@check_manually' => url('admin/reports/updates/check', array('query' => $destination)),
 329    ));
 330  }
 331  
 332  /**
 333   * Internal helper to try to get the update information from the cache
 334   * if possible, and to refresh the cache when necessary.
 335   *
 336   * In addition to checking the cache lifetime, this function also ensures that
 337   * there are no .info files for enabled modules or themes that have a newer
 338   * modification timestamp than the last time we checked for available update
 339   * data. If any .info file was modified, it almost certainly means a new
 340   * version of something was installed. Without fresh available update data,
 341   * the logic in update_calculate_project_data() will be wrong and produce
 342   * confusing, bogus results.
 343   *
 344   * @param $refresh
 345   *   Boolean to indicate if this method should refresh the cache automatically
 346   *   if there's no data.
 347   *
 348   * @see update_refresh()
 349   * @see update_get_projects()
 350   */
 351  function update_get_available($refresh = FALSE) {
 352    module_load_include('inc', 'update', 'update.compare');
 353    $available = array();
 354  
 355    // First, make sure that none of the .info files have a change time
 356    // newer than the last time we checked for available updates.
 357    $needs_refresh = FALSE;
 358    $last_check = variable_get('update_last_check', 0);
 359    $projects = update_get_projects();
 360    foreach ($projects as $key => $project) {
 361      if ($project['info']['_info_file_ctime'] > $last_check) {
 362        $needs_refresh = TRUE;
 363        break;
 364      }
 365    }
 366    if (!$needs_refresh && ($cache = _update_cache_get('update_available_releases')) && $cache->expire > time()) {
 367      $available = $cache->data;
 368    }
 369    elseif ($needs_refresh || $refresh) {
 370      // If we need to refresh due to a newer .info file, ignore the argument
 371      // and force the refresh (e.g., even for update_requirements()) to prevent
 372      // bogus results.
 373      $available = update_refresh();
 374    }
 375    return $available;
 376  }
 377  
 378  /**
 379   * Wrapper to load the include file and then refresh the release data.
 380   */
 381  function update_refresh() {
 382    module_load_include('inc', 'update', 'update.fetch');
 383    return _update_refresh();
 384  }
 385  
 386  /**
 387   * Implementation of hook_mail().
 388   *
 389   * Constructs the email notification message when the site is out of date.
 390   *
 391   * @param $key
 392   *   Unique key to indicate what message to build, always 'status_notify'.
 393   * @param $message
 394   *   Reference to the message array being built.
 395   * @param $params
 396   *   Array of parameters to indicate what kind of text to include in the
 397   *   message body. This is a keyed array of message type ('core' or 'contrib')
 398   *   as the keys, and the status reason constant (UPDATE_NOT_SECURE, etc) for
 399   *   the values.
 400   *
 401   * @see drupal_mail()
 402   * @see _update_cron_notify()
 403   * @see _update_message_text()
 404   */
 405  function update_mail($key, &$message, $params) {
 406    $language = $message['language'];
 407    $langcode = $language->language;
 408    $message['subject'] .= t('New release(s) available for !site_name', array('!site_name' => variable_get('site_name', 'Drupal')), $langcode);
 409    foreach ($params as $msg_type => $msg_reason) {
 410      $message['body'][] = _update_message_text($msg_type, $msg_reason, FALSE, $language);
 411    }
 412    $message['body'][] = t('See the available updates page for more information:', array(), $langcode) ."\n". url('admin/reports/updates', array('absolute' => TRUE, 'language' => $language));
 413  }
 414  
 415  /**
 416   * Helper function to return the appropriate message text when the site is out
 417   * of date or missing a security update.
 418   *
 419   * These error messages are shared by both update_requirements() for the
 420   * site-wide status report at admin/reports/status and in the body of the
 421   * notification emails generated by update_cron().
 422   *
 423   * @param $msg_type
 424   *   String to indicate what kind of message to generate. Can be either
 425   *   'core' or 'contrib'.
 426   * @param $msg_reason
 427   *   Integer constant specifying why message is generated.
 428   * @param $report_link
 429   *   Boolean that controls if a link to the updates report should be added.
 430   * @param $language
 431   *   An optional language object to use.
 432   * @return
 433   *   The properly translated error message for the given key.
 434   */
 435  function _update_message_text($msg_type, $msg_reason, $report_link = FALSE, $language = NULL) {
 436    $langcode = isset($language) ? $language->language : NULL;
 437    $text = '';
 438    switch ($msg_reason) {
 439      case UPDATE_NOT_SECURE:
 440        if ($msg_type == 'core') {
 441          $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);
 442        }
 443        else {
 444          $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(), $langcode);
 445        }
 446        break;
 447  
 448      case UPDATE_REVOKED:
 449        if ($msg_type == 'core') {
 450          $text = t('Your version of Drupal has been revoked and is no longer available for download. Upgrading is strongly recommended!', array(), $langcode);
 451        }
 452        else {
 453          $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(), $langcode);
 454        }
 455        break;
 456  
 457      case UPDATE_NOT_SUPPORTED:
 458        if ($msg_type == 'core') {
 459          $text = t('Your version of Drupal is no longer supported. Upgrading is strongly recommended!', array(), $langcode);
 460        }
 461        else {
 462          $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(), $langcode);
 463        }
 464        break;
 465  
 466      case UPDATE_NOT_CURRENT:
 467        if ($msg_type == 'core') {
 468          $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);
 469        }
 470        else {
 471          $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(), $langcode);
 472        }
 473        break;
 474  
 475      case UPDATE_UNKNOWN:
 476      case UPDATE_NOT_CHECKED:
 477      case UPDATE_NOT_FETCHED:
 478        if ($msg_type == 'core') {
 479          $text = t('There was a problem determining the status of available updates for your version of Drupal.', array(), $langcode);
 480        }
 481        else {
 482          $text = t('There was a problem determining the status of available updates for one or more of your modules or themes.', array(), $langcode);
 483        }
 484        break;
 485    }
 486  
 487    if ($report_link) {
 488      $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);
 489    }
 490  
 491    return $text;
 492  }
 493  
 494  /**
 495   * Private sort function to order projects based on their status.
 496   *
 497   * @see update_requirements()
 498   * @see uasort()
 499   */
 500  function _update_project_status_sort($a, $b) {
 501    // The status constants are numerically in the right order, so we can
 502    // usually subtract the two to compare in the order we want. However,
 503    // negative status values should be treated as if they are huge, since we
 504    // always want them at the bottom of the list.
 505    $a_status = $a['status'] > 0 ? $a['status'] : (-10 * $a['status']);
 506    $b_status = $b['status'] > 0 ? $b['status'] : (-10 * $b['status']);
 507    return $a_status - $b_status;
 508  }
 509  
 510  /**
 511   * @defgroup update_status_cache Private update status cache system
 512   * @{
 513   *
 514   * We specifically do NOT use the core cache API for saving the fetched data
 515   * about available updates. It is vitally important that this cache is only
 516   * cleared when we're populating it after successfully fetching new available
 517   * update data. Usage of the core cache API results in all sorts of potential
 518   * problems that would result in attempting to fetch available update data all
 519   * the time, including if a site has a "minimum cache lifetime" (which is both
 520   * a minimum and a maximum) defined, or if a site uses memcache or another
 521   * plug-able cache system that assumes volatile caches.
 522   *
 523   * Update module still uses the {cache_update} table, but instead of using
 524   * cache_set(), cache_get(), and cache_clear_all(), there are private helper
 525   * functions that implement these same basic tasks but ensure that the cache
 526   * is not prematurely cleared, and that the data is always stored in the
 527   * database, even if memcache or another cache backend is in use.
 528   */
 529  
 530  /**
 531   * Store data in the private update status cache table.
 532   *
 533   * Note: this function completely ignores the {cache_update}.headers field
 534   * since that is meaningless for the kinds of data we're caching.
 535   *
 536   * @param $cid
 537   *   The cache ID to save the data with.
 538   * @param $data
 539   *   The data to store.
 540   * @param $expire
 541   *   One of the following values:
 542   *   - CACHE_PERMANENT: Indicates that the item should never be removed except
 543   *     by explicitly using _update_cache_clear() or update_invalidate_cache().
 544   *   - A Unix timestamp: Indicates that the item should be kept at least until
 545   *     the given time, after which it will be invalidated.
 546   */
 547  function _update_cache_set($cid, $data, $expire) {
 548    $serialized = 0;
 549    if (is_object($data) || is_array($data)) {
 550      $data = serialize($data);
 551      $serialized = 1;
 552    }
 553    $created = time();
 554    db_query("UPDATE {cache_update} SET data = %b, created = %d, expire = %d, serialized = %d WHERE cid = '%s'", $data, $created, $expire, $serialized, $cid);
 555    if (!db_affected_rows()) {
 556      @db_query("INSERT INTO {cache_update} (cid, data, created, expire, serialized) VALUES ('%s', %b, %d, %d, %d)", $cid, $data, $created, $expire, $serialized);
 557    }
 558  }
 559  
 560  /**
 561   * Retrieve data from the private update status cache table.
 562   *
 563   * @param $cid
 564   *   The cache ID to retrieve.
 565   * @return
 566   *   The data for the given cache ID, or NULL if the ID was not found.
 567   */
 568  function _update_cache_get($cid) {
 569    $cache = db_fetch_object(db_query("SELECT data, created, expire, serialized FROM {cache_update} WHERE cid = '%s'", $cid));
 570    if (isset($cache->data)) {
 571      $cache->data = db_decode_blob($cache->data);
 572      if ($cache->serialized) {
 573        $cache->data = unserialize($cache->data);
 574      }
 575    }
 576    return $cache;
 577  }
 578  
 579  /**
 580   * Invalidates specific cached data relating to update status.
 581   *
 582   * @param $cid
 583   *   Optional cache ID of the record to clear from the private update module
 584   *   cache. If empty, all records will be cleared from the table.
 585   */
 586  function _update_cache_clear($cid = NULL) {
 587    if (empty($cid)) {
 588      db_query("TRUNCATE TABLE {cache_update}");
 589    }
 590    else {
 591      db_query("DELETE FROM {cache_update} WHERE cid = '%s'", $cid);
 592    }
 593  }
 594  
 595  /**
 596   * Implementation of hook_flush_caches().
 597   *
 598   * Called from update.php (among others) to flush the caches.
 599   * Since we're running update.php, we are likely to install a new version of
 600   * something, in which case, we want to check for available update data again.
 601   * However, because we have our own caching system, we need to directly clear
 602   * the database table ourselves at this point and return nothing, for example,
 603   * on sites that use memcache where cache_clear_all() won't know how to purge
 604   * this data.
 605   *
 606   * However, we only want to do this from update.php, since otherwise, we'd
 607   * lose all the available update data on every cron run. So, we specifically
 608   * check if the site is in MAINTENANCE_MODE == 'update' (which indicates
 609   * update.php is running, not update module... alas for overloaded names).
 610   */
 611  function update_flush_caches() {
 612    if (defined('MAINTENANCE_MODE') && MAINTENANCE_MODE == 'update') {
 613      _update_cache_clear();
 614    }
 615    return array();
 616  }
 617  
 618  /**
 619   * Invalidates all cached data relating to update status.
 620   */
 621  function update_invalidate_cache() {
 622    _update_cache_clear();
 623  }
 624  
 625  /**
 626   * @} End of "defgroup update_status_cache".
 627   */