cms/drupal/includes/session.inc
changeset 541 e756a8c72c3d
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/cms/drupal/includes/session.inc	Fri Sep 08 12:04:06 2017 +0200
@@ -0,0 +1,535 @@
+<?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).
+  $insecure_session_name = substr(session_name(), 1);
+  if (empty($sid) || (!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 TRUE;
+    }
+
+    // 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;
+    $user = drupal_anonymous_user();
+    // Less random sessions (which are much faster to generate) are used for
+    // anonymous users than are generated in drupal_session_regenerate() when
+    // a user becomes authenticated.
+    session_id(drupal_random_key());
+    if ($is_https && variable_get('https', FALSE)) {
+      $insecure_session_name = substr(session_name(), 1);
+      $session_id = drupal_random_key();
+      $_COOKIE[$insecure_session_name] = $session_id;
+    }
+  }
+  date_default_timezone_set(drupal_get_user_timezone());
+}
+
+/**
+ * Starts a session forcefully, 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, $is_https;
+  // Nothing to do if we are not allowed to change the session.
+  if (!drupal_save_session()) {
+    return;
+  }
+
+  if ($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_random_key();
+    // 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()) {
+    $old_session_id = session_id();
+  }
+  session_id(drupal_random_key());
+
+  if (isset($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, $is_https;
+
+  // Nothing to do if we are not allowed to change the session.
+  if (!drupal_save_session()) {
+    return TRUE;
+  }
+
+  // Delete session data.
+  db_delete('sessions')
+    ->condition($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);
+  }
+
+  return 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) {
+  // Nothing to do if we are not allowed to change the session.
+  if (!drupal_save_session()) {
+    return;
+  }
+
+  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) {
+  // PHP session ID, session, and cookie handling happens in the global scope.
+  // This value has to persist across calls to drupal_static_reset(), since a
+  // potentially wrong or disallowed session would be written otherwise.
+  static $save_session = TRUE;
+  if (isset($status)) {
+    $save_session = $status;
+  }
+  return $save_session;
+}