mirror of
https://github.com/moodle/moodle.git
synced 2025-01-19 14:27:22 +01:00
308 lines
10 KiB
PHP
308 lines
10 KiB
PHP
<?php
|
|
// This file is part of Moodle - http://moodle.org/
|
|
//
|
|
// Moodle is free software: you can redistribute it and/or modify
|
|
// it under the terms of the GNU General Public License as published by
|
|
// the Free Software Foundation, either version 3 of the License, or
|
|
// (at your option) any later version.
|
|
//
|
|
// Moodle is distributed in the hope that it will be useful,
|
|
// but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
// GNU General Public License for more details.
|
|
//
|
|
// You should have received a copy of the GNU General Public License
|
|
// along with Moodle. If not, see <http://www.gnu.org/licenses/>.
|
|
|
|
/**
|
|
* Database based session handler.
|
|
*
|
|
* @package core
|
|
* @copyright 2013 Petr Skoda {@link http://skodak.org}
|
|
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
|
|
*/
|
|
|
|
namespace core\session;
|
|
|
|
use SessionHandlerInterface;
|
|
|
|
/**
|
|
* Database based session handler.
|
|
*
|
|
* @package core
|
|
* @copyright 2013 Petr Skoda {@link http://skodak.org}
|
|
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
|
|
*/
|
|
class database extends handler implements SessionHandlerInterface {
|
|
/** @var \stdClass $record session record */
|
|
protected $recordid = null;
|
|
|
|
/** @var \moodle_database $database session database */
|
|
protected $database = null;
|
|
|
|
/** @var bool $failed session read/init failed, do not write back to DB */
|
|
protected $failed = false;
|
|
|
|
/** @var string $lasthash hash of the session data content */
|
|
protected $lasthash = null;
|
|
|
|
/** @var int $acquiretimeout how long to wait for session lock */
|
|
protected $acquiretimeout = 120;
|
|
|
|
/**
|
|
* Create new instance of handler.
|
|
*/
|
|
public function __construct() {
|
|
global $DB, $CFG;
|
|
// Note: we store the reference here because we need to modify database in shutdown handler.
|
|
$this->database = $DB;
|
|
|
|
if (!empty($CFG->session_database_acquire_lock_timeout)) {
|
|
$this->acquiretimeout = (int)$CFG->session_database_acquire_lock_timeout;
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Init session handler.
|
|
*/
|
|
public function init() {
|
|
if (!$this->database->session_lock_supported()) {
|
|
throw new exception('sessionhandlerproblem', 'error', '', null, 'Database does not support session locking');
|
|
}
|
|
|
|
$result = session_set_save_handler($this);
|
|
if (!$result) {
|
|
throw new exception('dbsessionhandlerproblem', 'error');
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Check the backend contains data for this session id.
|
|
*
|
|
* Note: this is intended to be called from manager::session_exists() only.
|
|
*
|
|
* @param string $sid
|
|
* @return bool true if session found.
|
|
*/
|
|
public function session_exists($sid) {
|
|
// It was already checked in the calling code that the record in sessions table exists.
|
|
return true;
|
|
}
|
|
|
|
/**
|
|
* Kill all active sessions, the core sessions table is
|
|
* purged afterwards.
|
|
*/
|
|
public function kill_all_sessions() {
|
|
// Nothing to do, the sessions table is cleared from core.
|
|
return;
|
|
}
|
|
|
|
/**
|
|
* Kill one session, the session record is removed afterwards.
|
|
* @param string $sid
|
|
*/
|
|
public function kill_session($sid) {
|
|
// Nothing to do, the sessions table is purged afterwards.
|
|
return;
|
|
}
|
|
|
|
/**
|
|
* Open session handler.
|
|
*
|
|
* {@see http://php.net/manual/en/function.session-set-save-handler.php}
|
|
*
|
|
* @param string $path
|
|
* @param string $name
|
|
* @return bool success
|
|
*/
|
|
public function open(string $path, string $name): bool {
|
|
// Note: we use the already open database.
|
|
return true;
|
|
}
|
|
|
|
/**
|
|
* Close session handler.
|
|
*
|
|
* {@see http://php.net/manual/en/function.session-set-save-handler.php}
|
|
*
|
|
* @return bool success
|
|
*/
|
|
public function close(): bool {
|
|
if ($this->recordid) {
|
|
try {
|
|
$this->database->release_session_lock($this->recordid);
|
|
} catch (\Exception $ex) {
|
|
// Ignore any problems.
|
|
}
|
|
}
|
|
$this->recordid = null;
|
|
$this->lasthash = null;
|
|
return true;
|
|
}
|
|
|
|
/**
|
|
* Read session handler.
|
|
*
|
|
* {@see http://php.net/manual/en/function.session-set-save-handler.php}
|
|
*
|
|
* @param string $sid
|
|
* @return string|false
|
|
*/
|
|
public function read(string $sid): string|false {
|
|
try {
|
|
if (!$record = $this->database->get_record('sessions', array('sid'=>$sid), 'id')) {
|
|
// Let's cheat and skip locking if this is the first access,
|
|
// do not create the record here, let the manager do it after session init.
|
|
$this->failed = false;
|
|
$this->recordid = null;
|
|
$this->lasthash = sha1('');
|
|
return '';
|
|
}
|
|
if ($this->recordid and $this->recordid != $record->id) {
|
|
error_log('Second session read with different record id detected, cannot read session');
|
|
$this->failed = true;
|
|
$this->recordid = null;
|
|
return '';
|
|
}
|
|
if (!$this->recordid) {
|
|
// Lock session if exists and not already locked.
|
|
if ($this->requires_write_lock()) {
|
|
$this->database->get_session_lock($record->id, $this->acquiretimeout);
|
|
}
|
|
$this->recordid = $record->id;
|
|
}
|
|
} catch (\dml_sessionwait_exception $ex) {
|
|
// This is a fatal error, better inform users.
|
|
// It should not happen very often - all pages that need long time to execute
|
|
// should close session immediately after access control checks.
|
|
error_log('Cannot obtain session lock for sid: '.$sid);
|
|
$this->failed = true;
|
|
throw $ex;
|
|
|
|
} catch (\Exception $ex) {
|
|
// Do not rethrow exceptions here, this should not happen.
|
|
error_log('Unknown exception when starting database session : '.$sid.' - '.$ex->getMessage());
|
|
$this->failed = true;
|
|
$this->recordid = null;
|
|
return '';
|
|
}
|
|
|
|
// Finally read the full session data because we know we have the lock now.
|
|
if (!$record = $this->database->get_record('sessions', array('id'=>$record->id), 'id, sessdata')) {
|
|
// Ignore - something else just deleted the session record.
|
|
$this->failed = true;
|
|
$this->recordid = null;
|
|
return '';
|
|
}
|
|
$this->failed = false;
|
|
|
|
if (is_null($record->sessdata)) {
|
|
$data = '';
|
|
$this->lasthash = sha1('');
|
|
} else {
|
|
$data = base64_decode($record->sessdata);
|
|
$this->lasthash = sha1($record->sessdata);
|
|
}
|
|
|
|
return $data;
|
|
}
|
|
|
|
/**
|
|
* Write session handler.
|
|
*
|
|
* {@see http://php.net/manual/en/function.session-set-save-handler.php}
|
|
*
|
|
* NOTE: Do not write to output or throw any exceptions!
|
|
* Hopefully the next page is going to display nice error or it recovers...
|
|
*
|
|
* @param string $id
|
|
* @param string $data
|
|
* @return bool success
|
|
*/
|
|
public function write(string $id, string $data): bool {
|
|
if ($this->failed) {
|
|
// Do not write anything back - we failed to start the session properly.
|
|
return false;
|
|
}
|
|
|
|
// There might be some binary mess.
|
|
$sessdata = base64_encode($data);
|
|
$hash = sha1($sessdata);
|
|
|
|
if ($hash === $this->lasthash) {
|
|
return true;
|
|
}
|
|
|
|
try {
|
|
if ($this->recordid) {
|
|
$this->database->set_field('sessions', 'sessdata', $sessdata, ['id' => $this->recordid]);
|
|
} else {
|
|
// This happens in the first request when session record was just created in manager.
|
|
$this->database->set_field('sessions', 'sessdata', $sessdata, ['sid' => $id]);
|
|
}
|
|
} catch (\Exception $ex) {
|
|
// Do not rethrow exceptions here, this should not happen.
|
|
// phpcs:ignore moodle.PHP.ForbiddenFunctions.FoundWithAlternative
|
|
error_log(
|
|
"Unknown exception when writing database session data : {$id} - " . $ex->getMessage(),
|
|
);
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
/**
|
|
* Destroy session handler.
|
|
*
|
|
* {@see http://php.net/manual/en/function.session-set-save-handler.php}
|
|
*
|
|
* @param string $id
|
|
* @return bool success
|
|
*/
|
|
public function destroy(string $id): bool {
|
|
if (!$session = $this->database->get_record('sessions', ['sid' => $id], 'id, sid')) {
|
|
if ($id == session_id()) {
|
|
$this->recordid = null;
|
|
$this->lasthash = null;
|
|
}
|
|
return true;
|
|
}
|
|
|
|
if ($this->recordid && ($session->id == $this->recordid)) {
|
|
try {
|
|
$this->database->release_session_lock($this->recordid);
|
|
} catch (\Exception $ex) {
|
|
// Ignore problems.
|
|
}
|
|
$this->recordid = null;
|
|
$this->lasthash = null;
|
|
}
|
|
|
|
$this->database->delete_records('sessions', ['id' => $session->id]);
|
|
|
|
return true;
|
|
}
|
|
|
|
/**
|
|
* GC session handler.
|
|
*
|
|
* {@see http://php.net/manual/en/function.session-set-save-handler.php}
|
|
*
|
|
* @param int $max_lifetime moodle uses special timeout rules
|
|
* @return bool success
|
|
*/
|
|
// phpcs:ignore moodle.NamingConventions.ValidVariableName.VariableNameUnderscore
|
|
public function gc(int $max_lifetime): int|false {
|
|
// This should do something only if cron is not running properly...
|
|
if (!$stalelifetime = ini_get('session.gc_maxlifetime')) {
|
|
return false;
|
|
}
|
|
$params = ['purgebefore' => (time() - $stalelifetime)];
|
|
$count = $this->database->count_records_select('sessions', 'userid = 0 AND timemodified < :purgebefore', $params);
|
|
$this->database->delete_records_select('sessions', 'userid = 0 AND timemodified < :purgebefore', $params);
|
|
|
|
return $count;
|
|
}
|
|
}
|