Merge pull request #353 from dchill42/session

Switched Sessions to use Drivers
Adding native PHP sessions and keeping original-flavor CI cookie sessions

2 files changed, 1010 insertions, 0 deletions

diff --git a/system/libraries/Session/drivers/Session_cookie.php b/system/libraries/Session/drivers/Session_cookie.php
new file mode 100755
index 000000000..69e5fde14
--- /dev/null
+++ b/system/libraries/Session/drivers/Session_cookie.php
@@ -0,0 +1,799 @@
+<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
+/**
+ * CodeIgniter
+ *
+ * An open source application development framework for PHP 5.2.4 or newer
+ *
+ * NOTICE OF LICENSE
+ *
+ * Licensed under the Open Software License version 3.0
+ *
+ * This source file is subject to the Open Software License (OSL 3.0) that is
+ * bundled with this package in the files license.txt / license.rst. It is
+ * also available through the world wide web at this URL:
+ * http://opensource.org/licenses/OSL-3.0
+ * If you did not receive a copy of the license and are unable to obtain it
+ * through the world wide web, please send an email to
+ * licensing@ellislab.com so we can send you a copy immediately.
+ *
+ * @package		CodeIgniter
+ * @author		EllisLab Dev Team
+ * @copyright	Copyright (c) 2008 - 2012, EllisLab, Inc. (http://ellislab.com/)
+ * @license		http://opensource.org/licenses/OSL-3.0 Open Software License (OSL 3.0)
+ * @link		http://codeigniter.com
+ * @since		Version 1.0
+ * @filesource
+ */
+
+/**
+ * Cookie-based session management driver
+ *
+ * This is the classic CI_Session functionality, as written by EllisLab, abstracted out to a driver.
+ *
+ * @package		CodeIgniter
+ * @subpackage	Libraries
+ * @category	Sessions
+ * @author		EllisLab Dev Team
+ * @link		http://codeigniter.com/user_guide/libraries/sessions.html
+ */
+class CI_Session_cookie extends CI_Session_driver {
+	/**
+	 * Whether to encrypt the session cookie
+	 *
+	 * @var bool
+	 */
+	public $sess_encrypt_cookie		= FALSE;
+
+	/**
+	 * Whether to use to the database for session storage
+	 *
+	 * @var bool
+	 */
+	public $sess_use_database		= FALSE;
+
+	/**
+	 * Name of the database table in which to store sessions
+	 *
+	 * @var string
+	 */
+	public $sess_table_name			= '';
+
+	/**
+	 * Length of time (in seconds) for sessions to expire
+	 *
+	 * @var int
+	 */
+	public $sess_expiration			= 7200;
+
+	/**
+	 * Whether to kill session on close of browser window
+	 *
+	 * @var bool
+	 */
+	public $sess_expire_on_close	= FALSE;
+
+	/**
+	 * Whether to match session on ip address
+	 *
+	 * @var bool
+	 */
+	public $sess_match_ip			= FALSE;
+
+	/**
+	 * Whether to match session on user-agent
+	 *
+	 * @var bool
+	 */
+	public $sess_match_useragent	= TRUE;
+
+	/**
+	 * Name of session cookie
+	 *
+	 * @var string
+	 */
+	public $sess_cookie_name		= 'ci_session';
+
+	/**
+	 * Session cookie prefix
+	 *
+	 * @var string
+	 */
+	public $cookie_prefix			= '';
+
+	/**
+	 * Session cookie path
+	 *
+	 * @var string
+	 */
+	public $cookie_path				= '';
+
+	/**
+	 * Session cookie domain
+	 *
+	 * @var string
+	 */
+	public $cookie_domain			= '';
+
+	/**
+	 * Whether to set the cookie only on HTTPS connections
+	 *
+	 * @var bool
+	 */
+	public $cookie_secure			= FALSE;
+
+	/**
+	 * Whether cookie should be allowed only to be sent by the server
+	 *
+	 * @var bool
+	 */
+	public $cookie_httponly 		= FALSE;
+
+	/**
+	 * Interval at which to update session
+	 *
+	 * @var int
+	 */
+	public $sess_time_to_update		= 300;
+
+	/**
+	 * Key with which to encrypt the session cookie
+	 *
+	 * @var string
+	 */
+	public $encryption_key			= '';
+
+	/**
+	 * Timezone to use for the current time
+	 *
+	 * @var string
+	 */
+	public $time_reference			= 'local';
+
+	/**
+	 * Session data
+	 *
+	 * @var array
+	 */
+	public $userdata				= array();
+
+	/**
+	 * Reference to CodeIgniter instance
+	 *
+	 * @var object
+	 */
+	public $CI;
+
+	/**
+	 * Current time
+	 *
+	 * @var int
+	 */
+	public $now;
+
+	/**
+	 * Default userdata keys
+	 *
+	 * @var	array
+	 */
+	protected $defaults = array(
+		'session_id' => NULL,
+		'ip_address' => NULL,
+		'user_agent' => NULL,
+		'last_activity' => NULL
+	);
+
+	/**
+	 * Data needs DB update flag
+	 *
+	 * @var	bool
+	 */
+	protected $data_dirty = FALSE;
+
+	/**
+	 * Initialize session driver object
+	 *
+	 * @access	protected
+	 * @return	void
+	 */
+	protected function initialize()
+	{
+		// Set the super object to a local variable for use throughout the class
+		$this->CI =& get_instance();
+
+		// Set all the session preferences, which can either be set
+		// manually via the $params array or via the config file
+		$prefs = array(
+			'sess_encrypt_cookie',
+			'sess_use_database',
+			'sess_table_name',
+			'sess_expiration',
+			'sess_expire_on_close',
+			'sess_match_ip',
+			'sess_match_useragent',
+			'sess_cookie_name',
+			'cookie_path',
+			'cookie_domain',
+			'cookie_secure',
+			'cookie_httponly',
+			'sess_time_to_update',
+			'time_reference',
+			'cookie_prefix',
+			'encryption_key'
+		);
+		foreach ($prefs as $key)
+		{
+			$this->$key = isset($this->_parent->params[$key]) ? $this->_parent->params[$key] :
+				$this->CI->config->item($key);
+		}
+
+		if ($this->encryption_key === '')
+		{
+			show_error('In order to use the Cookie Session driver you are required to set an encryption key '.
+				'in your config file.');
+		}
+
+		// Load the string helper so we can use the strip_slashes() function
+		$this->CI->load->helper('string');
+
+		// Do we need encryption? If so, load the encryption class
+		if ($this->sess_encrypt_cookie === TRUE)
+		{
+			$this->CI->load->library('encrypt');
+		}
+
+		// Check for database
+		if ($this->sess_use_database === TRUE && $this->sess_table_name !== '')
+		{
+			// Load database driver
+			$this->CI->load->database();
+
+			// Register shutdown function
+			register_shutdown_function(array($this, '_update_db'));
+		}
+
+		// Set the "now" time. Can either be GMT or server time, based on the config prefs.
+		// We use this to set the "last activity" time
+		$this->now = $this->_get_time();
+
+		// Set the session length. If the session expiration is
+		// set to zero we'll set the expiration two years from now.
+		if ($this->sess_expiration === 0)
+		{
+			$this->sess_expiration = (60*60*24*365*2);
+		}
+
+		// Set the cookie name
+		$this->sess_cookie_name = $this->cookie_prefix.$this->sess_cookie_name;
+
+		// Run the Session routine. If a session doesn't exist we'll
+		// create a new one. If it does, we'll update it.
+		if ( ! $this->_sess_read())
+		{
+			$this->_sess_create();
+		}
+		else
+		{
+			$this->_sess_update();
+		}
+
+		// Delete expired sessions if necessary
+		$this->_sess_gc();
+	}
+
+	/**
+	 * Write the session data
+	 *
+	 * @return	void
+	 */
+	public function sess_save()
+	{
+		// Check for database
+		if ($this->sess_use_database === TRUE)
+		{
+			// Mark custom data as dirty so we know to update the DB
+			$this->data_dirty = TRUE;
+		}
+
+		// Write the cookie
+		$this->_set_cookie();
+	}
+
+	/**
+	 * Destroy the current session
+	 *
+	 * @return	void
+	 */
+	public function sess_destroy()
+	{
+		// Kill the session DB row
+		if ($this->sess_use_database === TRUE && isset($this->userdata['session_id']))
+		{
+			$this->CI->db->delete($this->sess_table_name, array('session_id' => $this->userdata['session_id']));
+		}
+
+		// Kill the cookie
+		$this->_setcookie($this->sess_cookie_name, addslashes(serialize(array())), ($this->now - 31500000),
+			$this->cookie_path, $this->cookie_domain, 0);
+
+		// Kill session data
+		$this->userdata = array();
+	}
+
+	/**
+	 * Regenerate the current session
+	 *
+	 * Regenerate the session id
+	 *
+	 * @param	boolean	Destroy session data flag (default: false)
+	 * @return	void
+	 */
+	public function sess_regenerate($destroy = false)
+	{
+		// Check destroy flag
+		if ($destroy)
+		{
+			// Destroy old session and create new one
+			$this->sess_destroy();
+			$this->_sess_create();
+		}
+		else
+		{
+			// Just force an update to recreate the id
+			$this->_sess_update(true);
+		}
+	}
+
+	/**
+	 * Get a reference to user data array
+	 *
+	 * @return	array - Reference to userdata
+	 */
+	public function &get_userdata()
+	{
+		// Return reference to array
+		return $this->userdata;
+	}
+
+	/**
+	 * Fetch the current session data if it exists
+	 *
+	 * @access	protected
+	 * @return	bool
+	 */
+	protected function _sess_read()
+	{
+		// Fetch the cookie
+		$session = $this->CI->input->cookie($this->sess_cookie_name);
+
+		// No cookie? Goodbye cruel world!...
+		if ($session === NULL)
+		{
+			log_message('debug', 'A session cookie was not found.');
+			return FALSE;
+		}
+
+		// Check for encryption
+		if ($this->sess_encrypt_cookie === TRUE)
+		{
+			// Decrypt the cookie data
+			$session = $this->CI->encrypt->decode($session);
+		}
+		else
+		{
+			// Encryption was not used, so we need to check the md5 hash in the last 32 chars
+			$len	 = strlen($session)-32;
+			$hash	 = substr($session, $len);
+			$session = substr($session, 0, $len);
+
+			// Does the md5 hash match? This is to prevent manipulation of session data in userspace
+			if ($hash !== md5($session.$this->encryption_key))
+			{
+				log_message('error', 'The session cookie data did not match what was expected. '.
+					'This could be a possible hacking attempt.');
+				$this->sess_destroy();
+				return FALSE;
+			}
+		}
+
+		// Unserialize the session array
+		$session = $this->_unserialize($session);
+
+		// Is the session data we unserialized an array with the correct format?
+		if ( ! is_array($session) || ! isset($session['session_id'], $session['ip_address'], $session['user_agent'],
+		$session['last_activity']))
+		{
+			$this->sess_destroy();
+			return FALSE;
+		}
+
+		// Is the session current?
+		if (($session['last_activity'] + $this->sess_expiration) < $this->now)
+		{
+			$this->sess_destroy();
+			return FALSE;
+		}
+
+		// Does the IP match?
+		if ($this->sess_match_ip === TRUE && $session['ip_address'] !== $this->CI->input->ip_address())
+		{
+			$this->sess_destroy();
+			return FALSE;
+		}
+
+		// Does the User Agent Match?
+		if ($this->sess_match_useragent === TRUE &&
+		trim($session['user_agent']) !== trim(substr($this->CI->input->user_agent(), 0, 120)))
+		{
+			$this->sess_destroy();
+			return FALSE;
+		}
+
+		// Is there a corresponding session in the DB?
+		if ($this->sess_use_database === TRUE)
+		{
+			$this->CI->db->where('session_id', $session['session_id']);
+
+			if ($this->sess_match_ip === TRUE)
+			{
+				$this->CI->db->where('ip_address', $session['ip_address']);
+			}
+
+			if ($this->sess_match_useragent === TRUE)
+			{
+				$this->CI->db->where('user_agent', $session['user_agent']);
+			}
+
+			$query = $this->CI->db->limit(1)->get($this->sess_table_name);
+
+			// No result? Kill it!
+			if ($query->num_rows() === 0)
+			{
+				$this->sess_destroy();
+				return FALSE;
+			}
+
+			// Is there custom data? If so, add it to the main session array
+			$row = $query->row();
+			if ( ! empty($row->user_data))
+			{
+				$custom_data = $this->_unserialize($row->user_data);
+
+				if (is_array($custom_data))
+				{
+					$session = $session + $custom_data;
+				}
+			}
+		}
+
+		// Session is valid!
+		$this->userdata = $session;
+		return TRUE;
+	}
+
+	/**
+	 * Create a new session
+	 *
+	 * @access	protected
+	 * @return	void
+	 */
+	protected function _sess_create()
+	{
+		// Initialize userdata
+		$this->userdata = array(
+			'session_id'	=> $this->_make_sess_id(),
+			'ip_address'	=> $this->CI->input->ip_address(),
+			'user_agent'	=> substr($this->CI->input->user_agent(), 0, 120),
+			'last_activity'	=> $this->now,
+		);
+
+		// Check for database
+		if ($this->sess_use_database === TRUE)
+		{
+			// Add empty user_data field and save the data to the DB
+			$this->CI->db->set('user_data', '')->insert($this->sess_table_name, $this->userdata);
+		}
+
+		// Write the cookie
+		$this->_set_cookie();
+	}
+
+	/**
+	 * Update an existing session
+	 *
+	 * @access	protected
+	 * @param	boolean	Force update flag (default: false)
+	 * @return	void
+	 */
+	protected function _sess_update($force = FALSE)
+	{
+		// We only update the session every five minutes by default (unless forced)
+		if ( ! $force && ($this->userdata['last_activity'] + $this->sess_time_to_update) >= $this->now)
+		{
+			return;
+		}
+
+		// Update last activity to now
+		$this->userdata['last_activity'] = $this->now;
+
+		// Save the old session id so we know which DB record to update
+		$old_sessid = $this->userdata['session_id'];
+
+		// Changing the session ID during an AJAX call causes problems
+		if ( ! $this->CI->input->is_ajax_request())
+		{
+			// Get new id
+			$this->userdata['session_id'] = $this->_make_sess_id();
+		}
+
+		// Check for database
+		if ($this->sess_use_database === TRUE)
+		{
+			// Update the session ID and last_activity field in the DB
+			$this->CI->db->update($this->sess_table_name, array(
+					 'last_activity' => $this->now,
+					 'session_id' => $this->userdata['session_id']
+			), array('session_id' => $old_sessid));
+		}
+
+		// Write the cookie
+		$this->_set_cookie();
+	}
+
+	/**
+	 * Update database with current data
+	 *
+	 * This gets called from the shutdown function and also
+	 * registered with PHP to run at the end of the request
+	 * so it's guaranteed to update even when a fatal error
+	 * occurs. The first call makes the update and clears the
+	 * dirty flag so it won't happen twice.
+	 */
+	public function _update_db()
+	{
+		// Check for database and dirty flag and unsaved
+		if ($this->sess_use_database === TRUE && $this->data_dirty === TRUE)
+		{
+			// Set up activity and data fields to be set
+			// If we don't find custom data, user_data will remain an empty string
+			$set = array(
+				'last_activity' => $this->userdata['last_activity'],
+				'user_data' => ''
+			);
+
+			// Get the custom userdata, leaving out the defaults
+			// (which get stored in the cookie)
+			$userdata = array_diff_key($this->userdata, $this->defaults);
+
+			// Did we find any custom data?
+			if ( ! empty($userdata))
+			{
+				// Serialize the custom data array so we can store it
+				$set['user_data'] = $this->_serialize($userdata);
+			}
+
+			// Run the update query
+			// Any time we change the session id, it gets updated immediately,
+			// so our where clause below is always safe
+			$this->CI->db->update($this->sess_table_name, $set, array('session_id' => $this->userdata['session_id']));
+
+			// Clear dirty flag to prevent double updates
+			$this->data_dirty = FALSE;
+
+			log_message('debug', 'CI_Session Data Saved To DB');
+		}
+	}
+
+	/**
+	 * Generate a new session id
+	 *
+	 * @return	string	Hashed session id
+	 */
+	protected function _make_sess_id()
+	{
+		$new_sessid = '';
+		do
+		{
+			$new_sessid .= mt_rand(0, mt_getrandmax());
+		}
+		while (strlen($new_sessid) < 32);
+
+		// To make the session ID even more secure we'll combine it with the user's IP
+		$new_sessid .= $this->CI->input->ip_address();
+
+		// Turn it into a hash and return
+		return md5(uniqid($new_sessid, TRUE));
+	}
+
+	/**
+	 * Get the "now" time
+	 *
+	 * @access	protected
+	 * @return	int	 Time
+	 */
+	protected function _get_time()
+	{
+		if ($this->time_reference === 'local' || $this->time_reference === date_default_timezone_get())
+		{
+			return time();
+		}
+
+		$datetime = new DateTime('now', new DateTimeZone($this->time_reference));
+		sscanf($datetime->format('j-n-Y G:i:s'), '%d-%d-%d %d:%d:%d', $day, $month, $year, $hour, $minute, $second);
+
+		return mktime($hour, $minute, $second, $month, $day, $year);
+	}
+
+	/**
+	 * Write the session cookie
+	 *
+	 * @access	protected
+	 * @return	void
+	 */
+	protected function _set_cookie()
+	{
+		// Get userdata (only defaults if database)
+		if ($this->sess_use_database === TRUE)
+		{
+			$cookie_data = array_intersect_key($this->userdata, $this->defaults);
+		}
+		else
+		{
+			$cookie_data = $this->userdata;
+		}
+
+		// Serialize the userdata for the cookie
+		$cookie_data = $this->_serialize($cookie_data);
+
+		if ($this->sess_encrypt_cookie === TRUE)
+		{
+			$cookie_data = $this->CI->encrypt->encode($cookie_data);
+		}
+		else
+		{
+			// if encryption is not used, we provide an md5 hash to prevent userside tampering
+			$cookie_data = $cookie_data.md5($cookie_data.$this->encryption_key);
+		}
+
+		$expire = ($this->sess_expire_on_close === TRUE) ? 0 : $this->sess_expiration + time();
+
+		// Set the cookie
+		$this->_setcookie($this->sess_cookie_name, $cookie_data, $expire, $this->cookie_path, $this->cookie_domain,
+			$this->cookie_secure, $this->cookie_httponly);
+	}
+
+	/**
+	 * Set a cookie with the system
+	 *
+	 * This abstraction of the setcookie call allows overriding for unit testing
+	 *
+	 * @access  protected
+	 * @param   string  Cookie name
+	 * @param   string  Cookie value
+	 * @param   int	 Expiration time
+	 * @param   string  Cookie path
+	 * @param   string  Cookie domain
+	 * @param   bool	Secure connection flag
+	 * @param   bool	HTTP protocol only flag
+	 * @return  void
+	 */
+	protected function _setcookie($name, $value = '', $expire = 0, $path = '', $domain = '', $secure = false,
+	$httponly = false)
+	{
+		// Set the cookie
+		setcookie($name, $value, $expire, $path, $domain, $secure, $httponly);
+	}
+
+	/**
+	 * Serialize an array
+	 *
+	 * This function first converts any slashes found in the array to a temporary
+	 * marker, so when it gets unserialized the slashes will be preserved
+	 *
+	 * @access	protected
+	 * @param	mixed	Data to serialize
+	 * @return	string	Serialized data
+	 */
+	protected function _serialize($data)
+	{
+		if (is_array($data))
+		{
+			array_walk_recursive($data, array(&$this, '_escape_slashes'));
+		}
+		elseif (is_string($data))
+		{
+			$data = str_replace('\\', '{{slash}}', $data);
+		}
+		return serialize($data);
+	}
+
+	/**
+	 * Escape slashes
+	 *
+	 * This function converts any slashes found into a temporary marker
+	 *
+	 * @access	protected
+	 * @param	string	Value
+	 * @param	string	Key
+	 * @return	void
+	 */
+	protected function _escape_slashes(&$val, $key)
+	{
+		if (is_string($val))
+		{
+			$val = str_replace('\\', '{{slash}}', $val);
+		}
+	}
+
+	/**
+	 * Unserialize
+	 *
+	 * This function unserializes a data string, then converts any
+	 * temporary slash markers back to actual slashes
+	 *
+	 * @access	protected
+	 * @param	mixed	Data to unserialize
+	 * @return	mixed	Unserialized data
+	 */
+	protected function _unserialize($data)
+	{
+		$data = @unserialize(strip_slashes(trim($data)));
+
+		if (is_array($data))
+		{
+			array_walk_recursive($data, array(&$this, '_unescape_slashes'));
+			return $data;
+		}
+
+		return is_string($data) ? str_replace('{{slash}}', '\\', $data) : $data;
+	}
+
+	/**
+	 * Unescape slashes
+	 *
+	 * This function converts any slash markers back into actual slashes
+	 *
+	 * @access	protected
+	 * @param	string	Value
+	 * @param	string	Key
+	 * @return	void
+	 */
+	protected function _unescape_slashes(&$val, $key)
+	{
+		if (is_string($val))
+		{
+	 		$val= str_replace('{{slash}}', '\\', $val);
+		}
+	}
+
+	/**
+	 * Garbage collection
+	 *
+	 * This deletes expired session rows from database
+	 * if the probability percentage is met
+	 *
+	 * @access	protected
+	 * @return	void
+	 */
+	protected function _sess_gc()
+	{
+		if ($this->sess_use_database !== TRUE)
+		{
+			return;
+		}
+
+		$probability = ini_get('session.gc_probability');
+		$divisor = ini_get('session.gc_divisor');
+
+		srand(time());
+		if ((mt_rand(0, $divisor) / $divisor) < $probability)
+		{
+			$expire = $this->now - $this->sess_expiration;
+			$this->CI->db->delete($this->sess_table_name, 'last_activity < '.$expire);
+
+			log_message('debug', 'Session garbage collection performed.');
+		}
+	}
+}
+
+/* End of file Session_cookie.php */
+/* Location: ./system/libraries/Session/drivers/Session_cookie.php */
diff --git a/system/libraries/Session/drivers/Session_native.php b/system/libraries/Session/drivers/Session_native.php
new file mode 100755
index 000000000..8ba8e749a
--- /dev/null
+++ b/system/libraries/Session/drivers/Session_native.php
@@ -0,0 +1,211 @@
+<?php  if ( ! defined('BASEPATH')) exit('No direct script access allowed');
+/**
+ * CodeIgniter
+ *
+ * An open source application development framework for PHP 5.1.6 or newer
+ *
+ * @package		CodeIgniter
+ * @author		ExpressionEngine	Dev Team
+ * @copyright	Copyright	(c) 2008 - 2010, EllisLab, Inc.
+ * @license		http://codeigniter.com/user_guide/license.html
+ * @link		http://codeigniter.com
+ * @since		Version	2.0
+ * @filesource
+ */
+
+
+/**
+ * Native PHP session management driver
+ *
+ * This is the driver that uses the native PHP $_SESSION array through the Session driver library.
+ *
+ * @package		CodeIgniter
+ * @subpackage	Libraries
+ * @category	Sessions
+ * @author		ExpressionEngine Dev Team
+ */
+class CI_Session_native extends CI_Session_driver {
+	/**
+	 * Initialize session driver object
+	 *
+	 * @access	protected
+	 * @return	void
+	 */
+	protected function initialize()
+	{
+		// Get config parameters
+		$config = array();
+		$CI =& get_instance();
+		$prefs = array(
+			'sess_cookie_name',
+			'sess_expire_on_close',
+			'sess_expiration',
+			'sess_match_ip',
+			'sess_match_useragent',
+			'sess_time_to_update',
+			'cookie_prefix',
+			'cookie_path',
+			'cookie_domain'
+		);
+		foreach ($prefs as $key)
+		{
+			$config[$key] = isset($this->_parent->params[$key]) ? $this->_parent->params[$key] :
+				$CI->config->item($key);
+		}
+
+		// Set session name, if specified
+		if ($config['sess_cookie_name'])
+		{
+			// Differentiate name from cookie driver with '_id' suffix
+			$name = $config['sess_cookie_name'].'_id';
+			if ($config['cookie_prefix'])
+			{
+				// Prepend cookie prefix
+				$name = $config['cookie_prefix'].$name;
+			}
+			session_name($name);
+		}
+
+		// Set expiration, path, and domain
+		$expire = 7200;
+		$path = '/';
+		$domain = '';
+		if ($config['sess_expiration'] !== FALSE)
+		{
+			// Default to 2 years if expiration is "0"
+			$expire = ($config['sess_expiration'] == 0) ? (60*60*24*365*2) : $config['sess_expiration'];
+		}
+		if ($config['cookie_path'])
+		{
+			// Use specified path
+			$path = $config['cookie_path'];
+		}
+		if ($config['cookie_domain'])
+		{
+			// Use specified domain
+			$domain = $config['cookie_domain'];
+		}
+		session_set_cookie_params($config['sess_expire_on_close'] ? 0 : $expire, $path, $domain);
+
+		// Start session
+		session_start();
+
+		// Check session expiration, ip, and agent
+		$now = time();
+		$destroy = FALSE;
+		if (isset($_SESSION['last_activity']) && ($_SESSION['last_activity'] + $expire) < $now)
+		{
+			// Expired - destroy
+			$destroy = TRUE;
+		}
+		else if ($config['sess_match_ip'] == TRUE && isset($_SESSION['ip_address']) &&
+		$_SESSION['ip_address'] != $CI->input->ip_address())
+		{
+			// IP doesn't match - destroy
+			$destroy = TRUE;
+		}
+		else if ($config['sess_match_useragent'] == TRUE && isset($_SESSION['user_agent']) &&
+		$_SESSION['user_agent'] != trim(substr($CI->input->user_agent(), 0, 50)))
+		{
+			// Agent doesn't match - destroy
+			$destroy = TRUE;
+		}
+
+		// Destroy expired or invalid session
+		if ($destroy)
+		{
+			// Clear old session and start new
+			$this->sess_destroy();
+			session_start();
+		}
+
+		// Check for update time
+		if ($config['sess_time_to_update'] && isset($_SESSION['last_activity']) &&
+		($_SESSION['last_activity'] + $config['sess_time_to_update']) < $now)
+		{
+			// Regenerate ID, but don't destroy session
+			$this->sess_regenerate(FALSE);
+		}
+
+		// Set activity time
+		$_SESSION['last_activity'] = $now;
+
+		// Set matching values as required
+		if ($config['sess_match_ip'] == TRUE && !isset($_SESSION['ip_address']))
+		{
+			// Store user IP address
+			$_SESSION['ip_address'] = $CI->input->ip_address();
+		}
+		if ($config['sess_match_useragent'] == TRUE && !isset($_SESSION['user_agent']))
+		{
+			// Store user agent string
+			$_SESSION['user_agent'] = trim(substr($CI->input->user_agent(), 0, 50));
+		}
+
+		// Make session ID available
+		$_SESSION['session_id'] = session_id();
+	}
+
+	/**
+	 * Save the session data
+	 *
+	 * @access	public
+	 * @return	void
+	 */
+	public function sess_save()
+	{
+		// Nothing to do - changes to $_SESSION are automatically saved
+	}
+
+	/**
+	 * Destroy the current session
+	 *
+	 * @access	public
+	 * @return	void
+	 */
+	public function sess_destroy()
+	{
+		// Cleanup session
+		$_SESSION = array();
+		$name = session_name();
+		if (isset($_COOKIE[$name]))
+		{
+			// Clear session cookie
+			$params = session_get_cookie_params();
+			setcookie($name, '', time() - 42000, $params['path'], $params['domain']);
+			unset($_COOKIE[$name]);
+		}
+		session_destroy();
+	}
+
+	/**
+	 * Regenerate the current session
+	 *
+	 * Regenerate the session id
+	 *
+	 * @access	public
+	 * @param	boolean	Destroy session data flag (default: FALSE)
+	 * @return	void
+	 */
+	public function sess_regenerate($destroy = FALSE)
+	{
+		// Just regenerate id, passing destroy flag
+		session_regenerate_id($destroy);
+		$_SESSION['session_id'] = session_id();
+	}
+
+	/**
+	 * Get a reference to user data array
+	 *
+	 * @access	public
+	 * @return	array	Reference to userdata
+	 */
+	public function &get_userdata()
+	{
+		// Just return reference to $_SESSION
+		return $_SESSION;
+	}
+}
+
+/* End of file Session_native.php */
+/* Location: ./system/libraries/Session/drivers/Session_native.php */