drupal/includes/session.inc

<?php
// $Id: session.inc,v 1.72 2009/09/28 22:22:54 dries Exp $

/**
 * @file
 * User session handling functions.
 *
 * The user-level session storage handlers:
 * - _drupal_session_open()
 * - _drupal_session_close()
 * - _drupal_session_read()
 * - _drupal_session_write()
 * - _drupal_session_destroy()
 * - _drupal_session_garbage_collection()
 * are assigned by session_set_save_handler() in bootstrap.inc and are called
 * automatically by PHP. These functions should not be called directly. Session
 * data should instead be accessed via the $_SESSION superglobal.
 */

/**
 * Session handler assigned by session_set_save_handler().
 *
 * This function is used to handle any initialization, such as file paths or
 * database connections, that is needed before accessing session data. Drupal
 * does not need to initialize anything in this function.
 *
 * This function should not be called directly.
 *
 * @return
 *   This function will always return TRUE.
 */
function _drupal_session_open() {
  return TRUE;
}

/**
 * Session handler assigned by session_set_save_handler().
 *
 * This function is used to close the current session. Because Drupal stores
 * session data in the database immediately on write, this function does
 * not need to do anything.
 *
 * This function should not be called directly.
 *
 * @return
 *   This function will always return TRUE.
 */
function _drupal_session_close() {
  return TRUE;
}

/**
 * Session handler assigned by session_set_save_handler().
 *
 * This function will be called by PHP to retrieve the current user's
 * session data, which is stored in the database. It also loads the
 * current user's appropriate roles into the user object.
 *
 * This function should not be called directly. Session data should
 * instead be accessed via the $_SESSION superglobal.
 *
 * @param $sid
 *   Session ID.
 * @return
 *   Either an array of the session data, or an empty string, if no data
 *   was found or the user is anonymous.
 */
function _drupal_session_read($sid) {
  global $user, $is_https;

  // Write and Close handlers are called after destructing objects
  // since PHP 5.0.5.
  // Thus destructors can use sessions but session handler can't use objects.
  // So we are moving session closure before destructing objects.
  register_shutdown_function('session_write_close');

  // Handle the case of first time visitors and clients that don't store
  // cookies (eg. web crawlers).
  $insecure_session_name = substr(session_name(), 1);
  if (!isset($_COOKIE[session_name()]) && !isset($_COOKIE[$insecure_session_name])) {
    $user = drupal_anonymous_user();
    return '';
  }

  // Otherwise, if the session is still active, we have a record of the
  // client's session in the database. If it's HTTPS then we are either have
  // a HTTPS session or we are about to log in so we check the sessions table
  // for an anonymous session wth the non-HTTPS-only cookie.
  if ($is_https) {
    $user = db_query("SELECT u.*, s.* FROM {users} u INNER JOIN {sessions} s ON u.uid = s.uid WHERE s.ssid = :ssid", array(':ssid' => $sid))->fetchObject();
    if (!$user) {
      if (isset($_COOKIE[$insecure_session_name])) {
        $user = db_query("SELECT u.*, s.* FROM {users} u INNER JOIN {sessions} s ON u.uid = s.uid WHERE s.sid = :sid AND s.uid = 0", array(
        ':sid' => $_COOKIE[$insecure_session_name]))
        ->fetchObject();
      }
    }
  }
  else {
    $user = db_query("SELECT u.*, s.* FROM {users} u INNER JOIN {sessions} s ON u.uid = s.uid WHERE s.sid = :sid", array(':sid' => $sid))->fetchObject();
  }

  // We found the client's session record and they are an authenticated user.
  if ($user && $user->uid > 0) {
    // This is done to unserialize the data member of $user.
    $user = drupal_unpack($user);

    // Add roles element to $user.
    $user->roles = array();
    $user->roles[DRUPAL_AUTHENTICATED_RID] = 'authenticated user';
    $user->roles += db_query("SELECT r.rid, r.name FROM {role} r INNER JOIN {users_roles} ur ON ur.rid = r.rid WHERE ur.uid = :uid", array(':uid' => $user->uid))->fetchAllKeyed(0, 1);
  }
  // We didn't find the client's record (session has expired), or they
  // are an anonymous user.
  else {
    $session = isset($user->session) ? $user->session : '';
    $user = drupal_anonymous_user($session);
  }

  return $user->session;
}

/**
 * Session handler assigned by session_set_save_handler().
 *
 * This function will be called by PHP to store the current user's
 * session, which Drupal saves to the database.
 *
 * This function should not be called directly. Session data should
 * instead be accessed via the $_SESSION superglobal.
 *
 * @param $sid
 *   Session ID.
 * @param $value
 *   Serialized array of the session data.
 * @return
 *   This function will always return TRUE.
 */
function _drupal_session_write($sid, $value) {
  global $user, $is_https;

  if (!drupal_save_session()) {
    // We don't have anything to do if we are not allowed to save the session.
    return;
  }

  $fields = array(
    'uid' => $user->uid,
    'cache' => isset($user->cache) ? $user->cache : 0,
    'hostname' => ip_address(),
    'session' => $value,
    'timestamp' => REQUEST_TIME,
  );
  $key = array('sid' => $sid);
  if ($is_https) {
    $key['ssid'] = $sid;
    $insecure_session_name = substr(session_name(), 1);
    // The "secure pages" setting allows a site to simultaneously use both
    // secure and insecure session cookies. If enabled, use the insecure session
    // identifier as the sid.
    if (variable_get('https', FALSE) && isset($_COOKIE[$insecure_session_name])) {
      $key['sid'] = $_COOKIE[$insecure_session_name];
    }
  }
  db_merge('sessions')
    ->key($key)
    ->fields($fields)
    ->execute();

  // Last access time is updated no more frequently than once every 180 seconds.
  // This reduces contention in the users table.
  if ($user->uid && REQUEST_TIME - $user->access > variable_get('session_write_interval', 180)) {
    db_update('users')
      ->fields(array(
        'access' => REQUEST_TIME
      ))
      ->condition('uid', $user->uid)
      ->execute();
  }

  return TRUE;
}

/**
 * Initialize the session handler, starting a session if needed.
 */
function drupal_session_initialize() {
  global $user;

  session_set_save_handler('_drupal_session_open', '_drupal_session_close', '_drupal_session_read', '_drupal_session_write', '_drupal_session_destroy', '_drupal_session_garbage_collection');

  if (isset($_COOKIE[session_name()])) {
    // If a session cookie exists, initialize the session. Otherwise the
    // session is only started on demand in drupal_session_commit(), making
    // anonymous users not use a session cookie unless something is stored in
    // $_SESSION. This allows HTTP proxies to cache anonymous pageviews.
    drupal_session_start();
    if (!empty($user->uid) || !empty($_SESSION)) {
      drupal_page_is_cacheable(FALSE);
    }
  }
  else {
    // Set a session identifier for this request. This is necessary because
    // we lazyly start sessions at the end of this request, and some
    // processes (like drupal_get_token()) needs to know the future
    // session ID in advance.
    $user = drupal_anonymous_user();
    session_id(md5(uniqid('', TRUE)));
  }
}

/**
 * Forcefully start a session, preserving already set session data.
 *
 * @ingroup php_wrappers
 */
function drupal_session_start() {
  if (!drupal_session_started()) {
    // Save current session data before starting it, as PHP will destroy it.
    $session_data = isset($_SESSION) ? $_SESSION : NULL;

    session_start();
    drupal_session_started(TRUE);

    // Restore session data.
    if (!empty($session_data)) {
      $_SESSION += $session_data;
    }
  }
}

/**
 * Commit the current session, if necessary.
 *
 * If an anonymous user already have an empty session, destroy it.
 */
function drupal_session_commit() {
  global $user;

  if (!drupal_save_session()) {
    // We don't have anything to do if we are not allowed to save the session.
    return;
  }

  if (empty($user->uid) && empty($_SESSION)) {
    // There is no session data to store, destroy the session if it was
    // previously started.
    if (drupal_session_started()) {
      session_destroy();
    }
  }
  else {
    // There is session data to store. Start the session if it is not already
    // started.
    if (!drupal_session_started()) {
      drupal_session_start();
    }
    // Write the session data.
    session_write_close();
  }
}

/**
 * Return whether a session has been started.
 */
function drupal_session_started($set = NULL) {
  static $session_started = FALSE;
  if (isset($set)) {
    $session_started = $set;
  }
  return $session_started && session_id();
}

/**
 * Called when an anonymous user becomes authenticated or vice-versa.
 *
 * @ingroup php_wrappers
 */
function drupal_session_regenerate() {
  global $user, $is_https;
  if ($is_https && variable_get('https', FALSE)) {
    $insecure_session_name = substr(session_name(), 1);
    $params = session_get_cookie_params();
    $session_id = md5(uniqid(mt_rand(), TRUE));
    setcookie($insecure_session_name, $session_id, REQUEST_TIME + $params['lifetime'], $params['path'], $params['domain'], FALSE, $params['httponly']);
    $_COOKIE[$insecure_session_name] = $session_id;
  }

  if (drupal_session_started()) {
    $old_session_id = session_id();
    session_regenerate_id();
  }
  else {
    // Start the session when it doesn't exist yet.
    // Preserve the logged in user, as it will be reset to anonymous
    // by _drupal_session_read.
    $account = $user;
    drupal_session_start();
    $user = $account;
  }

  if (isset($old_session_id)) {
    db_update('sessions')
      ->fields(array(
        $is_https ? 'ssid' : 'sid' => session_id()
      ))
      ->condition('sid', $old_session_id)
      ->execute();
  }
}

/**
 * Counts how many users are active on the site.
 *
 * Counts how many users have sessions which have been active since the
 * specified time. Can count either anonymous sessions or
 * authenticated sessions.
 *
 * @param int $timestamp.
 *   A Unix timestamp. Users who have been active since this time will be
 *   counted. The default is 0, which counts all existing sessions.
 * @param boolean $anonymous
 *   TRUE counts only anonymous users.
 *   FALSE counts only authenticated users.
 * @return int
 *   The number of users with sessions.
 */
function drupal_session_count($timestamp = 0, $anonymous = TRUE) {
  $query = db_select('sessions');
  $query->addExpression('COUNT(sid)', 'count');
  $query->condition('timestamp', $timestamp, '>=');
  $query->condition('uid', 0, $anonymous ? '=' : '>');
  return $query->execute()->fetchField();
}

/**
 * Session handler assigned by session_set_save_handler().
 *
 * Cleanup a specific session.
 *
 * @param string $sid
 *   Session ID.
 */
function _drupal_session_destroy($sid) {
  global $user, $is_https;

  // Delete session data.
  db_delete('sessions')
    ->condition($is_https ? 'ssid' : 'sid', $sid)
    ->execute();

  // Reset $_SESSION and $user to prevent a new session from being started
  // in drupal_session_commit().
  $_SESSION = array();
  $user = drupal_anonymous_user();

  // Unset the session cookies.
  _drupal_session_delete_cookie(session_name());
  if ($is_https) {
    _drupal_session_delete_cookie(substr(session_name(), 1), TRUE);
  }
}

/**
 * Deletes the session cookie.
 *
 * @param $name
 *   Name of session cookie to delete.
 * @param $force_insecure
 *   Fornce cookie to be insecure.
 */
function _drupal_session_delete_cookie($name, $force_insecure = FALSE) {
  if (isset($_COOKIE[$name])) {
    $params = session_get_cookie_params();
    setcookie($name, '', REQUEST_TIME - 3600, $params['path'], $params['domain'], !$force_insecure && $params['secure'], $params['httponly']);
    unset($_COOKIE[$name]);
  }
}

/**
 * End a specific user's session(s).
 *
 * @param string $uid
 *   User ID.
 */
function drupal_session_destroy_uid($uid) {
  db_delete('sessions')
    ->condition('uid', $uid)
    ->execute();
}

/**
 * Session handler assigned by session_set_save_handler().
 *
 * Cleanup stalled sessions.
 *
 * @param int $lifetime
 *   The value of session.gc_maxlifetime, passed by PHP.
 *   Sessions not updated for more than $lifetime seconds will be removed.
 */
function _drupal_session_garbage_collection($lifetime) {
  // Be sure to adjust 'php_value session.gc_maxlifetime' to a large enough
  // value. For example, if you want user sessions to stay in your database
  // for three weeks before deleting them, you need to set gc_maxlifetime
  // to '1814400'. At that value, only after a user doesn't log in after
  // three weeks (1814400 seconds) will his/her session be removed.
  db_delete('sessions')
    ->condition('timestamp', REQUEST_TIME - $lifetime, '<')
    ->execute();
  return TRUE;
}

/**
 * Determine whether to save session data of the current request.
 *
 * This function allows the caller to temporarily disable writing of
 * session data, should the request end while performing potentially
 * dangerous operations, such as manipulating the global $user object.
 * See http://drupal.org/node/218104 for usage.
 *
 * @param $status
 *   Disables writing of session data when FALSE, (re-)enables
 *   writing when TRUE.
 * @return
 *   FALSE if writing session data has been disabled. Otherwise, TRUE.
 */
function drupal_save_session($status = NULL) {
  $save_session = &drupal_static(__FUNCTION__, TRUE);
  if (isset($status)) {
    $save_session = $status;
  }
  return $save_session;
}
1	<?php
2	// $Id: session.inc,v 1.72 2009/09/28 22:22:54 dries Exp $
3
4	/**
5	* @file
6	* User session handling functions.
7	*
8	* The user-level session storage handlers:
9	* - _drupal_session_open()
10	* - _drupal_session_close()
11	* - _drupal_session_read()
12	* - _drupal_session_write()
13	* - _drupal_session_destroy()
14	* - _drupal_session_garbage_collection()
15	* are assigned by session_set_save_handler() in bootstrap.inc and are called
16	* automatically by PHP. These functions should not be called directly. Session
17	* data should instead be accessed via the $_SESSION superglobal.
18	*/
19
20	/**
21	* Session handler assigned by session_set_save_handler().
22	*
23	* This function is used to handle any initialization, such as file paths or
24	* database connections, that is needed before accessing session data. Drupal
25	* does not need to initialize anything in this function.
26	*
27	* This function should not be called directly.
28	*
29	* @return
30	* This function will always return TRUE.
31	*/
32	function _drupal_session_open() {
33	return TRUE;
34	}
35
36	/**
37	* Session handler assigned by session_set_save_handler().
38	*
39	* This function is used to close the current session. Because Drupal stores
40	* session data in the database immediately on write, this function does
41	* not need to do anything.
42	*
43	* This function should not be called directly.
44	*
45	* @return
46	* This function will always return TRUE.
47	*/
48	function _drupal_session_close() {
49	return TRUE;
50	}
51
52	/**
53	* Session handler assigned by session_set_save_handler().
54	*
55	* This function will be called by PHP to retrieve the current user's
56	* session data, which is stored in the database. It also loads the
57	* current user's appropriate roles into the user object.
58	*
59	* This function should not be called directly. Session data should
60	* instead be accessed via the $_SESSION superglobal.
61	*
62	* @param $sid
63	* Session ID.
64	* @return
65	* Either an array of the session data, or an empty string, if no data
66	* was found or the user is anonymous.
67	*/
68	function _drupal_session_read($sid) {
69	global $user, $is_https;
70
71	// Write and Close handlers are called after destructing objects
72	// since PHP 5.0.5.
73	// Thus destructors can use sessions but session handler can't use objects.
74	// So we are moving session closure before destructing objects.
75	register_shutdown_function('session_write_close');
76
77	// Handle the case of first time visitors and clients that don't store
78	// cookies (eg. web crawlers).
79	$insecure_session_name = substr(session_name(), 1);
80	if (!isset($_COOKIE[session_name()]) && !isset($_COOKIE[$insecure_session_name])) {
81	$user = drupal_anonymous_user();
82	return '';
83	}
84
85	// Otherwise, if the session is still active, we have a record of the
86	// client's session in the database. If it's HTTPS then we are either have
87	// a HTTPS session or we are about to log in so we check the sessions table
88	// for an anonymous session wth the non-HTTPS-only cookie.
89	if ($is_https) {
90	$user = db_query("SELECT u., s. FROM {users} u INNER JOIN {sessions} s ON u.uid = s.uid WHERE s.ssid = :ssid", array(':ssid' => $sid))->fetchObject();
91	if (!$user) {
92	if (isset($_COOKIE[$insecure_session_name])) {
93	$user = db_query("SELECT u., s. FROM {users} u INNER JOIN {sessions} s ON u.uid = s.uid WHERE s.sid = :sid AND s.uid = 0", array(
94	':sid' => $_COOKIE[$insecure_session_name]))
95	->fetchObject();
96	}
97	}
98	}
99	else {
100	$user = db_query("SELECT u., s. FROM {users} u INNER JOIN {sessions} s ON u.uid = s.uid WHERE s.sid = :sid", array(':sid' => $sid))->fetchObject();
101	}
102
103	// We found the client's session record and they are an authenticated user.
104	if ($user && $user->uid > 0) {
105	// This is done to unserialize the data member of $user.
106	$user = drupal_unpack($user);
107
108	// Add roles element to $user.
109	$user->roles = array();
110	$user->roles[DRUPAL_AUTHENTICATED_RID] = 'authenticated user';
111	$user->roles += db_query("SELECT r.rid, r.name FROM {role} r INNER JOIN {users_roles} ur ON ur.rid = r.rid WHERE ur.uid = :uid", array(':uid' => $user->uid))->fetchAllKeyed(0, 1);
112	}
113	// We didn't find the client's record (session has expired), or they
114	// are an anonymous user.
115	else {
116	$session = isset($user->session) ? $user->session : '';
117	$user = drupal_anonymous_user($session);
118	}
119
120	return $user->session;
121	}
122
123	/**
124	* Session handler assigned by session_set_save_handler().
125	*
126	* This function will be called by PHP to store the current user's
127	* session, which Drupal saves to the database.
128	*
129	* This function should not be called directly. Session data should
130	* instead be accessed via the $_SESSION superglobal.
131	*
132	* @param $sid
133	* Session ID.
134	* @param $value
135	* Serialized array of the session data.
136	* @return
137	* This function will always return TRUE.
138	*/
139	function _drupal_session_write($sid, $value) {
140	global $user, $is_https;
141
142	if (!drupal_save_session()) {
143	// We don't have anything to do if we are not allowed to save the session.
144	return;
145	}
146
147	$fields = array(
148	'uid' => $user->uid,
149	'cache' => isset($user->cache) ? $user->cache : 0,
150	'hostname' => ip_address(),
151	'session' => $value,
152	'timestamp' => REQUEST_TIME,
153	);
154	$key = array('sid' => $sid);
155	if ($is_https) {
156	$key['ssid'] = $sid;
157	$insecure_session_name = substr(session_name(), 1);
158	// The "secure pages" setting allows a site to simultaneously use both
159	// secure and insecure session cookies. If enabled, use the insecure session
160	// identifier as the sid.
161	if (variable_get('https', FALSE) && isset($_COOKIE[$insecure_session_name])) {
162	$key['sid'] = $_COOKIE[$insecure_session_name];
163	}
164	}
165	db_merge('sessions')
166	->key($key)
167	->fields($fields)
168	->execute();
169
170	// Last access time is updated no more frequently than once every 180 seconds.
171	// This reduces contention in the users table.
172	if ($user->uid && REQUEST_TIME - $user->access > variable_get('session_write_interval', 180)) {
173	db_update('users')
174	->fields(array(
175	'access' => REQUEST_TIME
176	))
177	->condition('uid', $user->uid)
178	->execute();
179	}
180
181	return TRUE;
182	}
183
184	/**
185	* Initialize the session handler, starting a session if needed.
186	*/
187	function drupal_session_initialize() {
188	global $user;
189
190	session_set_save_handler('_drupal_session_open', '_drupal_session_close', '_drupal_session_read', '_drupal_session_write', '_drupal_session_destroy', '_drupal_session_garbage_collection');
191
192	if (isset($_COOKIE[session_name()])) {
193	// If a session cookie exists, initialize the session. Otherwise the
194	// session is only started on demand in drupal_session_commit(), making
195	// anonymous users not use a session cookie unless something is stored in
196	// $_SESSION. This allows HTTP proxies to cache anonymous pageviews.
197	drupal_session_start();
198	if (!empty($user->uid) \|\| !empty($_SESSION)) {
199	drupal_page_is_cacheable(FALSE);
200	}
201	}
202	else {
203	// Set a session identifier for this request. This is necessary because
204	// we lazyly start sessions at the end of this request, and some
205	// processes (like drupal_get_token()) needs to know the future
206	// session ID in advance.
207	$user = drupal_anonymous_user();
208	session_id(md5(uniqid('', TRUE)));
209	}
210	}
211
212	/**
213	* Forcefully start a session, preserving already set session data.
214	*
215	* @ingroup php_wrappers
216	*/
217	function drupal_session_start() {
218	if (!drupal_session_started()) {
219	// Save current session data before starting it, as PHP will destroy it.
220	$session_data = isset($_SESSION) ? $_SESSION : NULL;
221
222	session_start();
223	drupal_session_started(TRUE);
224
225	// Restore session data.
226	if (!empty($session_data)) {
227	$_SESSION += $session_data;
228	}
229	}
230	}
231
232	/**
233	* Commit the current session, if necessary.
234	*
235	* If an anonymous user already have an empty session, destroy it.
236	*/
237	function drupal_session_commit() {
238	global $user;
239
240	if (!drupal_save_session()) {
241	// We don't have anything to do if we are not allowed to save the session.
242	return;
243	}
244
245	if (empty($user->uid) && empty($_SESSION)) {
246	// There is no session data to store, destroy the session if it was
247	// previously started.
248	if (drupal_session_started()) {
249	session_destroy();
250	}
251	}
252	else {
253	// There is session data to store. Start the session if it is not already
254	// started.
255	if (!drupal_session_started()) {
256	drupal_session_start();
257	}
258	// Write the session data.
259	session_write_close();
260	}
261	}
262
263	/**
264	* Return whether a session has been started.
265	*/
266	function drupal_session_started($set = NULL) {
267	static $session_started = FALSE;
268	if (isset($set)) {
269	$session_started = $set;
270	}
271	return $session_started && session_id();
272	}
273
274	/**
275	* Called when an anonymous user becomes authenticated or vice-versa.
276	*
277	* @ingroup php_wrappers
278	*/
279	function drupal_session_regenerate() {
280	global $user, $is_https;
281	if ($is_https && variable_get('https', FALSE)) {
282	$insecure_session_name = substr(session_name(), 1);
283	$params = session_get_cookie_params();
284	$session_id = md5(uniqid(mt_rand(), TRUE));
285	setcookie($insecure_session_name, $session_id, REQUEST_TIME + $params['lifetime'], $params['path'], $params['domain'], FALSE, $params['httponly']);
286	$_COOKIE[$insecure_session_name] = $session_id;
287	}
288
289	if (drupal_session_started()) {
290	$old_session_id = session_id();
291	session_regenerate_id();
292	}
293	else {
294	// Start the session when it doesn't exist yet.
295	// Preserve the logged in user, as it will be reset to anonymous
296	// by _drupal_session_read.
297	$account = $user;
298	drupal_session_start();
299	$user = $account;
300	}
301
302	if (isset($old_session_id)) {
303	db_update('sessions')
304	->fields(array(
305	$is_https ? 'ssid' : 'sid' => session_id()
306	))
307	->condition('sid', $old_session_id)
308	->execute();
309	}
310	}
311
312	/**
313	* Counts how many users are active on the site.
314	*
315	* Counts how many users have sessions which have been active since the
316	* specified time. Can count either anonymous sessions or
317	* authenticated sessions.
318	*
319	* @param int $timestamp.
320	* A Unix timestamp. Users who have been active since this time will be
321	* counted. The default is 0, which counts all existing sessions.
322	* @param boolean $anonymous
323	* TRUE counts only anonymous users.
324	* FALSE counts only authenticated users.
325	* @return int
326	* The number of users with sessions.
327	*/
328	function drupal_session_count($timestamp = 0, $anonymous = TRUE) {
329	$query = db_select('sessions');
330	$query->addExpression('COUNT(sid)', 'count');
331	$query->condition('timestamp', $timestamp, '>=');
332	$query->condition('uid', 0, $anonymous ? '=' : '>');
333	return $query->execute()->fetchField();
334	}
335
336	/**
337	* Session handler assigned by session_set_save_handler().
338	*
339	* Cleanup a specific session.
340	*
341	* @param string $sid
342	* Session ID.
343	*/
344	function _drupal_session_destroy($sid) {
345	global $user, $is_https;
346
347	// Delete session data.
348	db_delete('sessions')
349	->condition($is_https ? 'ssid' : 'sid', $sid)
350	->execute();
351
352	// Reset $_SESSION and $user to prevent a new session from being started
353	// in drupal_session_commit().
354	$_SESSION = array();
355	$user = drupal_anonymous_user();
356
357	// Unset the session cookies.
358	_drupal_session_delete_cookie(session_name());
359	if ($is_https) {
360	_drupal_session_delete_cookie(substr(session_name(), 1), TRUE);
361	}
362	}
363
364	/**
365	* Deletes the session cookie.
366	*
367	* @param $name
368	* Name of session cookie to delete.
369	* @param $force_insecure
370	* Fornce cookie to be insecure.
371	*/
372	function _drupal_session_delete_cookie($name, $force_insecure = FALSE) {
373	if (isset($_COOKIE[$name])) {
374	$params = session_get_cookie_params();
375	setcookie($name, '', REQUEST_TIME - 3600, $params['path'], $params['domain'], !$force_insecure && $params['secure'], $params['httponly']);
376	unset($_COOKIE[$name]);
377	}
378	}
379
380	/**
381	* End a specific user's session(s).
382	*
383	* @param string $uid
384	* User ID.
385	*/
386	function drupal_session_destroy_uid($uid) {
387	db_delete('sessions')
388	->condition('uid', $uid)
389	->execute();
390	}
391
392	/**
393	* Session handler assigned by session_set_save_handler().
394	*
395	* Cleanup stalled sessions.
396	*
397	* @param int $lifetime
398	* The value of session.gc_maxlifetime, passed by PHP.
399	* Sessions not updated for more than $lifetime seconds will be removed.
400	*/
401	function _drupal_session_garbage_collection($lifetime) {
402	// Be sure to adjust 'php_value session.gc_maxlifetime' to a large enough
403	// value. For example, if you want user sessions to stay in your database
404	// for three weeks before deleting them, you need to set gc_maxlifetime
405	// to '1814400'. At that value, only after a user doesn't log in after
406	// three weeks (1814400 seconds) will his/her session be removed.
407	db_delete('sessions')
408	->condition('timestamp', REQUEST_TIME - $lifetime, '<')
409	->execute();
410	return TRUE;
411	}
412
413	/**
414	* Determine whether to save session data of the current request.
415	*
416	* This function allows the caller to temporarily disable writing of
417	* session data, should the request end while performing potentially
418	* dangerous operations, such as manipulating the global $user object.
419	* See http://drupal.org/node/218104 for usage.
420	*
421	* @param $status
422	* Disables writing of session data when FALSE, (re-)enables
423	* writing when TRUE.
424	* @return
425	* FALSE if writing session data has been disabled. Otherwise, TRUE.
426	*/
427	function drupal_save_session($status = NULL) {
428	$save_session = &drupal_static(__FUNCTION__, TRUE);
429	if (isset($status)) {
430	$save_session = $status;
431	}
432	return $save_session;
433	}