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<?php
/**
* @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;
}
/**
* Reads an entire session from the database (internal use only).
*
* Also initializes the $user object for the user associated with the session.
* This function is registered with session_set_save_handler() to support
* database-backed sessions. It is called on every page load when PHP sets
* up the $_SESSION superglobal.
*
* This function is an internal function and must not be called directly.
* Doing so may result in logging out the current user, corrupting session data
* or other unexpected behavior. Session data must always be accessed via the
* $_SESSION superglobal.
*
* @param $sid
* The session ID of the session to retrieve.
*
* @return
* The user's session, or an empty string if no session exists.
*/
function _drupal_session_read($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.
drupal_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])) {
$user = drupal_anonymous_user();
return '';
}
// Otherwise, if the session is still active, we have a record of the
// client's session in the database. If it's HTTPS then we are either have
// a HTTPS session or we are about to log in so we check the sessions table
// for an anonymous session with the non-HTTPS-only cookie.
if ($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' => $sid))->fetchObject();
}
// We found the client's session record and they are an authenticated,
// active user.
if ($user && $user->uid > 0 && $user->status == 1) {
// This is done to unserialize the data member of $user.
$user->data = unserialize($user->data);
// 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' => $user->uid))->fetchAllKeyed(0, 1);
}
elseif ($user) {
// The user is anonymous or blocked. Only preserve two fields from the
// {sessions} table.
$account = drupal_anonymous_user();
$account->session = $user->session;
$account->timestamp = $user->timestamp;
$user = $account;
}
else {
// The session has expired.
$user = drupal_anonymous_user();
$user->session = '';
}
// Store the session that was read for comparison in _drupal_session_write().
$last_read = &drupal_static('drupal_session_last_read');
$last_read = array(
'sid' => $sid,
'value' => $user->session,
);
return $user->session;
}
/**
* Writes an entire session to the database (internal use only).
*
* This function is registered with session_set_save_handler() to support
* database-backed sessions.
*
* This function is an internal function and must not be called directly.
* Doing so may result in corrupted session data or other unexpected behavior.
* Session data must always be accessed via the $_SESSION superglobal.
*
* @param $sid
* The session ID of the session to write to.
* @param $value
* Session data to write as a serialized string.
*
* @return
* Always returns TRUE.
*/
function _drupal_session_write($sid, $value) {
global $user, $is_https;
// The exception handler is not active at this point, so we need to do it
// manually.
try {
if (!drupal_save_session()) {
// We don't have anything to do if we are not allowed to save the session.
return;
}
// Check whether $_SESSION has been changed in this request.
$last_read = &drupal_static('drupal_session_last_read');
$is_changed = !isset($last_read) || $last_read['sid'] != $sid || $last_read['value'] !== $value;
// For performance reasons, do not update the sessions table, unless
// $_SESSION has changed or more than 180 has passed since the last update.
if ($is_changed || !isset($user->timestamp) || REQUEST_TIME - $user->timestamp > variable_get('session_write_interval', 180)) {
// Either ssid or sid or both will be added from $key below.
$fields = array(
'uid' => $user->uid,
'cache' => isset($user->cache) ? $user->cache : 0,
'hostname' => ip_address(),
'session' => $value,
'timestamp' => REQUEST_TIME,
);
// Use the session ID as 'sid' and an empty string as 'ssid' by default.
// _drupal_session_read() does not allow empty strings so that's a safe
// default.
$key = array('sid' => $sid, 'ssid' => '');
// On HTTPS connections, use the session ID as both 'sid' and 'ssid'.
if ($is_https) {
$key['ssid'] = $sid;
// The "secure pages" setting allows a site to simultaneously use both
// secure and insecure session cookies. If enabled and both cookies are
// presented then use both keys.
if (variable_get('https', FALSE)) {
$insecure_session_name = substr(session_name(), 1);
if (isset($_COOKIE[$insecure_session_name])) {
$key['sid'] = $_COOKIE[$insecure_session_name];
}
}
}
elseif (variable_get('https', FALSE)) {
unset($key['ssid']);
}
db_merge('sessions')
->key($key)
->fields($fields)
->execute();
}
// Likewise, do not update access time more than once per 180 seconds.
if ($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;
}
catch (Exception $exception) {
require_once DRUPAL_ROOT . '/includes/errors.inc';
// If we are displaying errors, then do so with no possibility of a further
// uncaught exception being thrown.
if (error_displayable()) {
print '<h1>Uncaught exception thrown in session handler.</h1>';
print '<p>' . _drupal_render_exception_safe($exception) . '</p><hr />';
}
return FALSE;
}
}
/**
* Initializes the session handler, starting a session if needed.
*/
function drupal_session_initialize() {
global $user, $is_https;
session_set_save_handler('_drupal_session_open', '_drupal_session_close', '_drupal_session_read', '_drupal_session_write', '_drupal_session_destroy', '_drupal_session_garbage_collection');
// We use !empty() in the following check to ensure that blank session IDs
// are not valid.
if (!empty($_COOKIE[session_name()]) || ($is_https && variable_get('https', FALSE) && !empty($_COOKIE[substr(session_name(), 1)]))) {
// 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 lazily start sessions at the end of this request, and some
// processes (like drupal_get_token()) needs to know the future
// session ID in advance.
$GLOBALS['lazy_session'] = TRUE;
$user = drupal_anonymous_user();
// Less random sessions (which are much faster to generate) are used for
// anonymous users than are generated in drupal_session_regenerate() when
// a user becomes authenticated.
session_id(drupal_hash_base64(uniqid(mt_rand(), TRUE)));
if ($is_https && variable_get('https', FALSE)) {
$insecure_session_name = substr(session_name(), 1);
$session_id = drupal_hash_base64(uniqid(mt_rand(), TRUE));
$_COOKIE[$insecure_session_name] = $session_id;
}
}
date_default_timezone_set(drupal_get_user_timezone());
}
/**
* Forcefully starts a session, preserving already set session data.
*
* @ingroup php_wrappers
*/
function drupal_session_start() {
// Command line clients do not support cookies nor sessions.
if (!drupal_session_started() && !drupal_is_cli()) {
// 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;
}
}
}
/**
* Commits the current session, if necessary.
*
* If an anonymous user already have an empty session, destroy it.
*/
function drupal_session_commit() {
global $user, $is_https;
if (!drupal_save_session()) {
// We don't have anything to do if we are not allowed to save the session.
return;
}
if (empty($user->uid) && empty($_SESSION)) {
// There is no session data to store, destroy the session if it was
// previously started.
if (drupal_session_started()) {
session_destroy();
}
}
else {
// There is session data to store. Start the session if it is not already
// started.
if (!drupal_session_started()) {
drupal_session_start();
if ($is_https && variable_get('https', FALSE)) {
$insecure_session_name = substr(session_name(), 1);
$params = session_get_cookie_params();
$expire = $params['lifetime'] ? REQUEST_TIME + $params['lifetime'] : 0;
setcookie($insecure_session_name, $_COOKIE[$insecure_session_name], $expire, $params['path'], $params['domain'], FALSE, $params['httponly']);
}
}
// Write the session data.
session_write_close();
}
}
/**
* Returns whether a session has been started.
*/
function drupal_session_started($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)) {
$insecure_session_name = substr(session_name(), 1);
if (!isset($GLOBALS['lazy_session']) && isset($_COOKIE[$insecure_session_name])) {
$old_insecure_session_id = $_COOKIE[$insecure_session_name];
}
$params = session_get_cookie_params();
$session_id = drupal_hash_base64(uniqid(mt_rand(), TRUE) . drupal_random_bytes(55));
// If a session cookie lifetime is set, the session will expire
// $params['lifetime'] seconds from the current request. If it is not set,
// it will expire when the browser is closed.
$expire = $params['lifetime'] ? REQUEST_TIME + $params['lifetime'] : 0;
setcookie($insecure_session_name, $session_id, $expire, $params['path'], $params['domain'], FALSE, $params['httponly']);
$_COOKIE[$insecure_session_name] = $session_id;
}
if (drupal_session_started()) {
$old_session_id = session_id();
}
session_id(drupal_hash_base64(uniqid(mt_rand(), TRUE) . drupal_random_bytes(55)));
if (isset($old_session_id)) {
$params = session_get_cookie_params();
$expire = $params['lifetime'] ? REQUEST_TIME + $params['lifetime'] : 0;
setcookie(session_name(), session_id(), $expire, $params['path'], $params['domain'], $params['secure'], $params['httponly']);
$fields = array('sid' => session_id());
if ($is_https) {
$fields['ssid'] = session_id();
// If the "secure pages" setting is enabled, use the newly-created
// insecure session identifier as the regenerated sid.
if (variable_get('https', FALSE)) {
$fields['sid'] = $session_id;
}
}
db_update('sessions')
->fields($fields)
->condition($is_https ? 'ssid' : 'sid', $old_session_id)
->execute();
}
elseif (isset($old_insecure_session_id)) {
// If logging in to the secure site, and there was no active session on the
// secure site but a session was active on the insecure site, update the
// insecure session with the new session identifiers.
db_update('sessions')
->fields(array('sid' => $session_id, 'ssid' => session_id()))
->condition('sid', $old_insecure_session_id)
->execute();
}
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;
}
date_default_timezone_set(drupal_get_user_timezone());
}
/**
* Session handler assigned by session_set_save_handler().
*
* Cleans up a specific session.
*
* @param $sid
* Session ID.
*/
function _drupal_session_destroy($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), FALSE);
}
elseif (variable_get('https', FALSE)) {
_drupal_session_delete_cookie('S' . session_name(), TRUE);
}
}
/**
* Deletes the session cookie.
*
* @param $name
* Name of session cookie to delete.
* @param boolean $secure
* Force the secure value of the cookie.
*/
function _drupal_session_delete_cookie($name, $secure = NULL) {
global $is_https;
if (isset($_COOKIE[$name]) || (!$is_https && $secure === TRUE)) {
$params = session_get_cookie_params();
if ($secure !== NULL) {
$params['secure'] = $secure;
}
setcookie($name, '', REQUEST_TIME - 3600, $params['path'], $params['domain'], $params['secure'], $params['httponly']);
unset($_COOKIE[$name]);
}
}
/**
* Ends a specific user's session(s).
*
* @param $uid
* User ID.
*/
function drupal_session_destroy_uid($uid) {
db_delete('sessions')
->condition('uid', $uid)
->execute();
}
/**
* Session handler assigned by session_set_save_handler().
*
* Cleans up stalled sessions.
*
* @param $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;
}
/**
* Determines 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;
}
