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   1  <?php
   2  // $Id: session.inc,v 1.44.2.7 2010/03/04 00:15:28 goba Exp $
   3  
   4  /**
   5   * @file
   6   * User session handling functions.
   7   */
   8  
   9  function sess_open($save_path, $session_name) {
  10    return TRUE;
  11  }
  12  
  13  function sess_close() {
  14    return TRUE;
  15  }
  16  
  17  function sess_read($key) {
  18    global $user;
  19  
  20    // Write and Close handlers are called after destructing objects since PHP 5.0.5
  21    // Thus destructors can use sessions but session handler can't use objects.
  22    // So we are moving session closure before destructing objects.
  23    register_shutdown_function('session_write_close');
  24  
  25    // Handle the case of first time visitors and clients that don't store cookies (eg. web crawlers).
  26    if (!isset($_COOKIE[session_name()])) {
  27      $user = drupal_anonymous_user();
  28      return '';
  29    }
  30  
  31    // Otherwise, if the session is still active, we have a record of the client's session in the database.
  32    $user = db_fetch_object(db_query("SELECT u.*, s.* FROM {users} u INNER JOIN {sessions} s ON u.uid = s.uid WHERE s.sid = '%s'", $key));
  33  
  34    // We found the client's session record and they are an authenticated,
  35    // active user.
  36    if ($user && $user->uid > 0 && $user->status == 1) {
  37      // This is done to unserialize the data member of $user
  38      $user = drupal_unpack($user);
  39  
  40      // Add roles element to $user
  41      $user->roles = array();
  42      $user->roles[DRUPAL_AUTHENTICATED_RID] = 'authenticated user';
  43      $result = db_query("SELECT r.rid, r.name FROM {role} r INNER JOIN {users_roles} ur ON ur.rid = r.rid WHERE ur.uid = %d", $user->uid);
  44      while ($role = db_fetch_object($result)) {
  45        $user->roles[$role->rid] = $role->name;
  46      }
  47    }
  48    // We didn't find the client's record (session has expired), or they are
  49    // blocked, or they are an anonymous user.
  50    else {
  51      $session = isset($user->session) ? $user->session : '';
  52      $user = drupal_anonymous_user($session);
  53    }
  54  
  55    return $user->session;
  56  }
  57  
  58  function sess_write($key, $value) {
  59    global $user;
  60  
  61    // If saving of session data is disabled or if the client doesn't have a session,
  62    // and one isn't being created ($value), do nothing. This keeps crawlers out of
  63    // the session table. This reduces memory and server load, and gives more useful
  64    // statistics. We can't eliminate anonymous session table rows without breaking
  65    // the throttle module and the "Who's Online" block.
  66    if (!session_save_session() || ($user->uid == 0 && empty($_COOKIE[session_name()]) && empty($value))) {
  67      return TRUE;
  68    }
  69  
  70    db_query("UPDATE {sessions} SET uid = %d, cache = %d, hostname = '%s', session = '%s', timestamp = %d WHERE sid = '%s'", $user->uid, isset($user->cache) ? $user->cache : '', ip_address(), $value, time(), $key);
  71    if (db_affected_rows()) {
  72      // Last access time is updated no more frequently than once every 180 seconds.
  73      // This reduces contention in the users table.
  74      if ($user->uid && time() - $user->access > variable_get('session_write_interval', 180)) {
  75        db_query("UPDATE {users} SET access = %d WHERE uid = %d", time(), $user->uid);
  76      }
  77    }
  78    else {
  79      // If this query fails, another parallel request probably got here first.
  80      // In that case, any session data generated in this request is discarded.
  81      @db_query("INSERT INTO {sessions} (sid, uid, cache, hostname, session, timestamp) VALUES ('%s', %d, %d, '%s', '%s', %d)", $key, $user->uid, isset($user->cache) ? $user->cache : '', ip_address(), $value, time());
  82    }
  83  
  84    return TRUE;
  85  }
  86  
  87  /**
  88   * Called when an anonymous user becomes authenticated or vice-versa.
  89   */
  90  function sess_regenerate() {
  91    $old_session_id = session_id();
  92  
  93    // We code around http://bugs.php.net/bug.php?id=32802 by destroying
  94    // the session cookie by setting expiration in the past (a negative
  95    // value).  This issue only arises in PHP versions before 4.4.0,
  96    // regardless of the Drupal configuration.
  97    // TODO: remove this when we require at least PHP 4.4.0
  98    if (isset($_COOKIE[session_name()])) {
  99      setcookie(session_name(), '', time() - 42000, '/');
 100    }
 101  
 102    session_regenerate_id();
 103  
 104    db_query("UPDATE {sessions} SET sid = '%s' WHERE sid = '%s'", session_id(), $old_session_id);
 105  }
 106  
 107  /**
 108   * Counts how many users have sessions. Can count either anonymous sessions or authenticated sessions.
 109   *
 110   * @param int $timestamp
 111   *   A Unix timestamp representing a point of time in the past.
 112   *   The default is 0, which counts all existing sessions.
 113   * @param boolean $anonymous
 114   *   TRUE counts only anonymous users.
 115   *   FALSE counts only authenticated users.
 116   * @return  int
 117   *   The number of users with sessions.
 118   */
 119  function sess_count($timestamp = 0, $anonymous = true) {
 120    $query = $anonymous ? ' AND uid = 0' : ' AND uid > 0';
 121    return db_result(db_query('SELECT COUNT(sid) AS count FROM {sessions} WHERE timestamp >= %d'. $query, $timestamp));
 122  }
 123  
 124  /**
 125   * Called by PHP session handling with the PHP session ID to end a user's session.
 126   *
 127   * @param  string $sid
 128   *   the session id
 129   */
 130  function sess_destroy_sid($sid) {
 131    db_query("DELETE FROM {sessions} WHERE sid = '%s'", $sid);
 132  }
 133  
 134  /**
 135   * End a specific user's session
 136   *
 137   * @param  string $uid
 138   *   the user id
 139   */
 140  function sess_destroy_uid($uid) {
 141    db_query('DELETE FROM {sessions} WHERE uid = %d', $uid);
 142  }
 143  
 144  function sess_gc($lifetime) {
 145    // Be sure to adjust 'php_value session.gc_maxlifetime' to a large enough
 146    // value. For example, if you want user sessions to stay in your database
 147    // for three weeks before deleting them, you need to set gc_maxlifetime
 148    // to '1814400'. At that value, only after a user doesn't log in after
 149    // three weeks (1814400 seconds) will his/her session be removed.
 150    db_query("DELETE FROM {sessions} WHERE timestamp < %d", time() - $lifetime);
 151  
 152    return TRUE;
 153  }
 154  
 155  /**
 156   * Determine whether to save session data of the current request.
 157   *
 158   * This function allows the caller to temporarily disable writing of session data,
 159   * should the request end while performing potentially dangerous operations, such as
 160   * manipulating the global $user object.  See http://drupal.org/node/218104 for usage
 161   *
 162   * @param $status
 163   *   Disables writing of session data when FALSE, (re-)enables writing when TRUE.
 164   * @return
 165   *   FALSE if writing session data has been disabled. Otherwise, TRUE.
 166   */
 167  function session_save_session($status = NULL) {
 168    static $save_session = TRUE;
 169    if (isset($status)) {
 170      $save_session = $status;
 171    }
 172    return ($save_session);
 173  }