system/libraries/Session.php - code-igniter-v3-giggi - Gitiles

 <?php  if ( ! defined('BASEPATH')) exit('No direct script access allowed');
 /**
  * CodeIgniter
  *
  * An open source application development framework for PHP 5.1.6 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 - 2011, 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
  */

 // ------------------------------------------------------------------------

 /**
  * Session Class
  *
  * @package		CodeIgniter
  * @subpackage	Libraries
  * @category	Sessions
  * @author		EllisLab Dev Team
  * @link		http://codeigniter.com/user_guide/libraries/sessions.html
  */
 class CI_Session {

 	var $sess_encrypt_cookie		= FALSE;
 	var $sess_use_database			= FALSE;
 	var $sess_table_name			= '';
 	var $sess_expiration			= 7200;
 	var $sess_expire_on_close		= FALSE;
 	var $sess_match_ip				= FALSE;
 	var $sess_match_useragent		= TRUE;
 	var $sess_cookie_name			= 'ci_session';
 	var $cookie_prefix				= '';
 	var $cookie_path				= '';
 	var $cookie_domain				= '';
 	var $cookie_secure				= FALSE;
 	var $sess_time_to_update		= 300;
 	var $encryption_key				= '';
 	var $flashdata_key				= 'flash';
 	var $time_reference				= 'time';
 	var $gc_probability				= 5;
 	var $userdata					= array();
 	var $CI;
 	var $now;

 	/**
 	 * Session Constructor
 	 *
 	 * The constructor runs the session routines automatically
 	 * whenever the class is instantiated.
 	 */
 	public function __construct($params = array())
 	{
 		log_message('debug', "Session Class Initialized");

 		// 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 above or via the config file
 		foreach (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', 'sess_time_to_update', 'time_reference', 'cookie_prefix', 'encryption_key') as $key)
 		{
 			$this->$key = (isset($params[$key])) ? $params[$key] : $this->CI->config->item($key);
 		}

 		if ($this->encryption_key == '')
 		{
 			show_error('In order to use the Session class 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');
 		}

 		// Are we using a database?  If so, load it
 		if ($this->sess_use_database === TRUE AND $this->sess_table_name != '')
 		{
 			$this->CI->load->database();
 		}

 		// 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 'old' flashdata (from last request)
 		$this->_flashdata_sweep();

 		// Mark all new flashdata as old (data will be deleted before next request)
 		$this->_flashdata_mark();

 		// Delete expired sessions if necessary
 		$this->_sess_gc();

 		log_message('debug', "Session routines successfully run");
 	}

 	// --------------------------------------------------------------------

 	/**
 	 * Fetch the current session data if it exists
 	 *
 	 * @access	public
 	 * @return	bool
 	 */
 	function sess_read()
 	{
 		// Fetch the cookie
 		$session = $this->CI->input->cookie($this->sess_cookie_name);

 		// No cookie?  Goodbye cruel world!...
 		if ($session === FALSE)
 		{
 			log_message('debug', 'A session cookie was not found.');
 			return FALSE;
 		}

 		// Decrypt the cookie data
 		if ($this->sess_encrypt_cookie == TRUE)
 		{
 			$session = $this->CI->encrypt->decode($session);
 		}
 		else
 		{
 			// encryption was not used, so we need to check the md5 hash
 			$hash	 = substr($session, strlen($session)-32); // get last 32 chars
 			$session = substr($session, 0, strlen($session)-32);

 			// 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($session) OR ! isset($session['session_id']) OR ! isset($session['ip_address']) OR ! isset($session['user_agent']) OR ! isset($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 AND $session['ip_address'] != $this->CI->input->ip_address())
 		{
 			$this->sess_destroy();
 			return FALSE;
 		}

 		// Does the User Agent Match?
 		if ($this->sess_match_useragent == TRUE AND trim($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 = $this->CI->db->get($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 = $query->row();
 			if (isset($row->user_data) AND $row->user_data != '')
 			{
 				$custom_data = $this->_unserialize($row->user_data);

 				if (is_array($custom_data))
 				{
 					foreach ($custom_data as $key => $val)
 					{
 						$session[$key] = $val;
 					}
 				}
 			}
 		}

 		// Session is valid!
 		$this->userdata = $session;
 		unset($session);

 		return TRUE;
 	}

 	// --------------------------------------------------------------------

 	/**
 	 * Write the session data
 	 *
 	 * @access	public
 	 * @return	void
 	 */
 	function sess_write()
 	{
 		// Are we saving custom data to the DB?  If not, all we do is update the cookie
 		if ($this->sess_use_database === FALSE)
 		{
 			$this->_set_cookie();
 			return;
 		}

 		// set the custom userdata, the session data we will set in a second
 		$custom_userdata = $this->userdata;
 		$cookie_userdata = array();

 		// Before continuing, we need to determine if there is any custom data to deal with.
 		// Let's determine this by removing the default indexes to see if there's anything left in the array
 		// and set the session data while we're at it
 		foreach (array('session_id','ip_address','user_agent','last_activity') as $val)
 		{
 			unset($custom_userdata[$val]);
 			$cookie_userdata[$val] = $this->userdata[$val];
 		}

 		// Did we find any custom data?  If not, we turn the empty array into a string
 		// since there's no reason to serialize and store an empty array in the DB
 		if (count($custom_userdata) === 0)
 		{
 			$custom_userdata = '';
 		}
 		else
 		{
 			// Serialize the custom data array so we can store it
 			$custom_userdata = $this->_serialize($custom_userdata);
 		}

 		// Run the update query
 		$this->CI->db->where('session_id', $this->userdata['session_id']);
 		$this->CI->db->update($this->sess_table_name, array('last_activity' => $this->userdata['last_activity'], 'user_data' => $custom_userdata));

 		// Write the cookie.  Notice that we manually pass the cookie data array to the
 		// _set_cookie() function. Normally that function will store $this->userdata, but
 		// in this case that array contains custom data, which we do not want in the cookie.
 		$this->_set_cookie($cookie_userdata);
 	}

 	// --------------------------------------------------------------------

 	/**
 	 * Create a new session
 	 *
 	 * @access	public
 	 * @return	void
 	 */
 	function sess_create()
 	{
 		$sessid = '';
 		while (strlen($sessid) < 32)
 		{
 			$sessid .= mt_rand(0, mt_getrandmax());
 		}

 		// To make the session ID even more secure we'll combine it with the user's IP
 		$sessid .= $this->CI->input->ip_address();

 		$this->userdata = array(
 							'session_id'	=> md5(uniqid($sessid, TRUE)),
 							'ip_address'	=> $this->CI->input->ip_address(),
 							'user_agent'	=> substr($this->CI->input->user_agent(), 0, 120),
 							'last_activity'	=> $this->now,
 							'user_data'		=> ''
 							);


 		// Save the data to the DB if needed
 		if ($this->sess_use_database === TRUE)
 		{
 			$this->CI->db->query($this->CI->db->insert_string($this->sess_table_name, $this->userdata));
 		}

 		// Write the cookie
 		$this->_set_cookie();
 	}

 	// --------------------------------------------------------------------

 	/**
 	 * Update an existing session
 	 *
 	 * @access	public
 	 * @return	void
 	 */
 	function sess_update()
 	{
 		// We only update the session every five minutes by default
 		if (($this->userdata['last_activity'] + $this->sess_time_to_update) >= $this->now)
 		{
 			return;
 		}

 		// Save the old session id so we know which record to
 		// update in the database if we need it
 		$old_sessid = $this->userdata['session_id'];
 		$new_sessid = '';
 		while (strlen($new_sessid) < 32)
 		{
 			$new_sessid .= mt_rand(0, mt_getrandmax());
 		}

 		// 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
 		$new_sessid = md5(uniqid($new_sessid, TRUE));

 		// Update the session data in the session data array
 		$this->userdata['session_id'] = $new_sessid;
 		$this->userdata['last_activity'] = $this->now;

 		// _set_cookie() will handle this for us if we aren't using database sessions
 		// by pushing all userdata to the cookie.
 		$cookie_data = NULL;

 		// Update the session ID and last_activity field in the DB if needed
 		if ($this->sess_use_database === TRUE)
 		{
 			// set cookie explicitly to only have our session data
 			$cookie_data = array();
 			foreach (array('session_id','ip_address','user_agent','last_activity') as $val)
 			{
 				$cookie_data[$val] = $this->userdata[$val];
 			}

 			$this->CI->db->query($this->CI->db->update_string($this->sess_table_name, array('last_activity' => $this->now, 'session_id' => $new_sessid), array('session_id' => $old_sessid)));
 		}

 		// Write the cookie
 		$this->_set_cookie($cookie_data);
 	}

 	// --------------------------------------------------------------------

 	/**
 	 * Destroy the current session
 	 *
 	 * @access	public
 	 * @return	void
 	 */
 	function sess_destroy()
 	{
 		// Kill the session DB row
 		if ($this->sess_use_database === TRUE AND isset($this->userdata['session_id']))
 		{
 			$this->CI->db->where('session_id', $this->userdata['session_id']);
 			$this->CI->db->delete($this->sess_table_name);
 		}

 		// Kill the cookie
 		setcookie(
 					$this->sess_cookie_name,
 					addslashes(serialize(array())),
 					($this->now - 31500000),
 					$this->cookie_path,
 					$this->cookie_domain,
 					0
 				);
 	}

 	// --------------------------------------------------------------------

 	/**
 	 * Fetch a specific item from the session array
 	 *
 	 * @access	public
 	 * @param	string
 	 * @return	string
 	 */
 	function userdata($item)
 	{
 		return ( ! isset($this->userdata[$item])) ? FALSE : $this->userdata[$item];
 	}

 	// --------------------------------------------------------------------

 	/**
 	 * Fetch all session data
 	 *
 	 * @access	public
 	 * @return	array
 	 */
 	function all_userdata()
 	{
 		return $this->userdata;
 	}

 	// --------------------------------------------------------------------

 	/**
 	 * Add or change data in the "userdata" array
 	 *
 	 * @access	public
 	 * @param	mixed
 	 * @param	string
 	 * @return	void
 	 */
 	function set_userdata($newdata = array(), $newval = '')
 	{
 		if (is_string($newdata))
 		{
 			$newdata = array($newdata => $newval);
 		}

 		if (count($newdata) > 0)
 		{
 			foreach ($newdata as $key => $val)
 			{
 				$this->userdata[$key] = $val;
 			}
 		}

 		$this->sess_write();
 	}

 	// --------------------------------------------------------------------

 	/**
 	 * Delete a session variable from the "userdata" array
 	 *
 	 * @access	array
 	 * @return	void
 	 */
 	function unset_userdata($newdata = array())
 	{
 		if (is_string($newdata))
 		{
 			$newdata = array($newdata => '');
 		}

 		if (count($newdata) > 0)
 		{
 			foreach ($newdata as $key => $val)
 			{
 				unset($this->userdata[$key]);
 			}
 		}

 		$this->sess_write();
 	}

 	// ------------------------------------------------------------------------

 	/**
 	 * Add or change flashdata, only available
 	 * until the next request
 	 *
 	 * @access	public
 	 * @param	mixed
 	 * @param	string
 	 * @return	void
 	 */
 	function set_flashdata($newdata = array(), $newval = '')
 	{
 		if (is_string($newdata))
 		{
 			$newdata = array($newdata => $newval);
 		}

 		if (count($newdata) > 0)
 		{
 			foreach ($newdata as $key => $val)
 			{
 				$flashdata_key = $this->flashdata_key.':new:'.$key;
 				$this->set_userdata($flashdata_key, $val);
 			}
 		}
 	}

 	// ------------------------------------------------------------------------

 	/**
 	 * Keeps existing flashdata available to next request.
 	 *
 	 * @access	public
 	 * @param	string
 	 * @return	void
 	 */
 	function keep_flashdata($key)
 	{
 		// 'old' flashdata gets removed.  Here we mark all
 		// flashdata as 'new' to preserve it from _flashdata_sweep()
 		// Note the function will return FALSE if the $key
 		// provided cannot be found
 		$old_flashdata_key = $this->flashdata_key.':old:'.$key;
 		$value = $this->userdata($old_flashdata_key);

 		$new_flashdata_key = $this->flashdata_key.':new:'.$key;
 		$this->set_userdata($new_flashdata_key, $value);
 	}

 	// ------------------------------------------------------------------------

 	/**
 	 * Fetch a specific flashdata item from the session array
 	 *
 	 * @access	public
 	 * @param	string
 	 * @return	string
 	 */
 	function flashdata($key)
 	{
 		$flashdata_key = $this->flashdata_key.':old:'.$key;
 		return $this->userdata($flashdata_key);
 	}

 	// ------------------------------------------------------------------------

 	/**
 	 * Identifies flashdata as 'old' for removal
 	 * when _flashdata_sweep() runs.
 	 *
 	 * @access	private
 	 * @return	void
 	 */
 	function _flashdata_mark()
 	{
 		$userdata = $this->all_userdata();
 		foreach ($userdata as $name => $value)
 		{
 			$parts = explode(':new:', $name);
 			if (is_array($parts) && count($parts) === 2)
 			{
 				$new_name = $this->flashdata_key.':old:'.$parts[1];
 				$this->set_userdata($new_name, $value);
 				$this->unset_userdata($name);
 			}
 		}
 	}

 	// ------------------------------------------------------------------------

 	/**
 	 * Removes all flashdata marked as 'old'
 	 *
 	 * @access	private
 	 * @return	void
 	 */

 	function _flashdata_sweep()
 	{
 		$userdata = $this->all_userdata();
 		foreach ($userdata as $key => $value)
 		{
 			if (strpos($key, ':old:'))
 			{
 				$this->unset_userdata($key);
 			}
 		}

 	}

 	// --------------------------------------------------------------------

 	/**
 	 * Get the "now" time
 	 *
 	 * @access	private
 	 * @return	string
 	 */
 	function _get_time()
 	{
 		if (strtolower($this->time_reference) == 'gmt')
 		{
 			$now = time();
 			$time = mktime(gmdate("H", $now), gmdate("i", $now), gmdate("s", $now), gmdate("m", $now), gmdate("d", $now), gmdate("Y", $now));
 		}
 		else
 		{
 			$time = time();
 		}

 		return $time;
 	}

 	// --------------------------------------------------------------------

 	/**
 	 * Write the session cookie
 	 *
 	 * @access	public
 	 * @return	void
 	 */
 	function _set_cookie($cookie_data = NULL)
 	{
 		if (is_null($cookie_data))
 		{
 			$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
 		setcookie(
 					$this->sess_cookie_name,
 					$cookie_data,
 					$expire,
 					$this->cookie_path,
 					$this->cookie_domain,
 					$this->cookie_secure
 				);
 	}

 	// --------------------------------------------------------------------

 	/**
 	 * 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	private
 	 * @param	array
 	 * @return	string
 	 */
 	function _serialize($data)
 	{
 		if (is_array($data))
 		{
 			array_walk_recursive($data, array(&$this, '_escape_slashes'));
 		}
 		else
 		{
 			if (is_string($data))
 			{
 				$data = str_replace('\\', '{{slash}}', $data);
 			}
 		}
 		return serialize($data);
 	}

 	/**
 	 * Escape slashes
 	 *
 	 * This function converts any slashes found into a temporary marker
 	 *
 	 * @access	private
 	 */
 	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	private
 	 * @param	array
 	 * @return	string
 	 */
 	function _unserialize($data)
 	{
 		$data = @unserialize(strip_slashes($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	private
 	 */
 	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	public
 	 * @return	void
 	 */
 	function _sess_gc()
 	{
 		if ($this->sess_use_database != TRUE)
 		{
 			return;
 		}

 		srand(time());
 		if ((rand() % 100) < $this->gc_probability)
 		{
 			$expire = $this->now - $this->sess_expiration;

 			$this->CI->db->where("last_activity < {$expire}");
 			$this->CI->db->delete($this->sess_table_name);

 			log_message('debug', 'Session garbage collection performed.');
 		}
 	}


 }
 // END Session Class

 /* End of file Session.php */
 /* Location: ./system/libraries/Session.php */
	<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
	/**
	* CodeIgniter
	*
	* An open source application development framework for PHP 5.1.6 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 - 2011, 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
	*/

	// ------------------------------------------------------------------------

	/**
	* Session Class
	*
	* @package CodeIgniter
	* @subpackage Libraries
	* @category Sessions
	* @author EllisLab Dev Team
	* @link http://codeigniter.com/user_guide/libraries/sessions.html
	*/
	class CI_Session {

	var $sess_encrypt_cookie = FALSE;
	var $sess_use_database = FALSE;
	var $sess_table_name = '';
	var $sess_expiration = 7200;
	var $sess_expire_on_close = FALSE;
	var $sess_match_ip = FALSE;
	var $sess_match_useragent = TRUE;
	var $sess_cookie_name = 'ci_session';
	var $cookie_prefix = '';
	var $cookie_path = '';
	var $cookie_domain = '';
	var $cookie_secure = FALSE;
	var $sess_time_to_update = 300;
	var $encryption_key = '';
	var $flashdata_key = 'flash';
	var $time_reference = 'time';
	var $gc_probability = 5;
	var $userdata = array();
	var $CI;
	var $now;

	/**
	* Session Constructor
	*
	* The constructor runs the session routines automatically
	* whenever the class is instantiated.
	*/
	public function __construct($params = array())
	{
	log_message('debug', "Session Class Initialized");

	// 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 above or via the config file
	foreach (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', 'sess_time_to_update', 'time_reference', 'cookie_prefix', 'encryption_key') as $key)
	{
	$this->$key = (isset($params[$key])) ? $params[$key] : $this->CI->config->item($key);
	}

	if ($this->encryption_key == '')
	{
	show_error('In order to use the Session class 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');
	}

	// Are we using a database? If so, load it
	if ($this->sess_use_database === TRUE AND $this->sess_table_name != '')
	{
	$this->CI->load->database();
	}

	// 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 = (6060243652);
	}

	// 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 'old' flashdata (from last request)
	$this->_flashdata_sweep();

	// Mark all new flashdata as old (data will be deleted before next request)
	$this->_flashdata_mark();

	// Delete expired sessions if necessary
	$this->_sess_gc();

	log_message('debug', "Session routines successfully run");
	}

	// --------------------------------------------------------------------

	/**
	* Fetch the current session data if it exists
	*
	* @access public
	* @return bool
	*/
	function sess_read()
	{
	// Fetch the cookie
	$session = $this->CI->input->cookie($this->sess_cookie_name);

	// No cookie? Goodbye cruel world!...
	if ($session === FALSE)
	{
	log_message('debug', 'A session cookie was not found.');
	return FALSE;
	}

	// Decrypt the cookie data
	if ($this->sess_encrypt_cookie == TRUE)
	{
	$session = $this->CI->encrypt->decode($session);
	}
	else
	{
	// encryption was not used, so we need to check the md5 hash
	$hash = substr($session, strlen($session)-32); // get last 32 chars
	$session = substr($session, 0, strlen($session)-32);

	// 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($session) OR ! isset($session['session_id']) OR ! isset($session['ip_address']) OR ! isset($session['user_agent']) OR ! isset($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 AND $session['ip_address'] != $this->CI->input->ip_address())
	{
	$this->sess_destroy();
	return FALSE;
	}

	// Does the User Agent Match?
	if ($this->sess_match_useragent == TRUE AND trim($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 = $this->CI->db->get($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 = $query->row();
	if (isset($row->user_data) AND $row->user_data != '')
	{
	$custom_data = $this->_unserialize($row->user_data);

	if (is_array($custom_data))
	{
	foreach ($custom_data as $key => $val)
	{
	$session[$key] = $val;
	}
	}
	}
	}

	// Session is valid!
	$this->userdata = $session;
	unset($session);

	return TRUE;
	}

	// --------------------------------------------------------------------

	/**
	* Write the session data
	*
	* @access public
	* @return void
	*/
	function sess_write()
	{
	// Are we saving custom data to the DB? If not, all we do is update the cookie
	if ($this->sess_use_database === FALSE)
	{
	$this->_set_cookie();
	return;
	}

	// set the custom userdata, the session data we will set in a second
	$custom_userdata = $this->userdata;
	$cookie_userdata = array();

	// Before continuing, we need to determine if there is any custom data to deal with.
	// Let's determine this by removing the default indexes to see if there's anything left in the array
	// and set the session data while we're at it
	foreach (array('session_id','ip_address','user_agent','last_activity') as $val)
	{
	unset($custom_userdata[$val]);
	$cookie_userdata[$val] = $this->userdata[$val];
	}

	// Did we find any custom data? If not, we turn the empty array into a string
	// since there's no reason to serialize and store an empty array in the DB
	if (count($custom_userdata) === 0)
	{
	$custom_userdata = '';
	}
	else
	{
	// Serialize the custom data array so we can store it
	$custom_userdata = $this->_serialize($custom_userdata);
	}

	// Run the update query
	$this->CI->db->where('session_id', $this->userdata['session_id']);
	$this->CI->db->update($this->sess_table_name, array('last_activity' => $this->userdata['last_activity'], 'user_data' => $custom_userdata));

	// Write the cookie. Notice that we manually pass the cookie data array to the
	// _set_cookie() function. Normally that function will store $this->userdata, but
	// in this case that array contains custom data, which we do not want in the cookie.
	$this->_set_cookie($cookie_userdata);
	}

	// --------------------------------------------------------------------

	/**
	* Create a new session
	*
	* @access public
	* @return void
	*/
	function sess_create()
	{
	$sessid = '';
	while (strlen($sessid) < 32)
	{
	$sessid .= mt_rand(0, mt_getrandmax());
	}

	// To make the session ID even more secure we'll combine it with the user's IP
	$sessid .= $this->CI->input->ip_address();

	$this->userdata = array(
	'session_id' => md5(uniqid($sessid, TRUE)),
	'ip_address' => $this->CI->input->ip_address(),
	'user_agent' => substr($this->CI->input->user_agent(), 0, 120),
	'last_activity' => $this->now,
	'user_data' => ''
	);


	// Save the data to the DB if needed
	if ($this->sess_use_database === TRUE)
	{
	$this->CI->db->query($this->CI->db->insert_string($this->sess_table_name, $this->userdata));
	}

	// Write the cookie
	$this->_set_cookie();
	}

	// --------------------------------------------------------------------

	/**
	* Update an existing session
	*
	* @access public
	* @return void
	*/
	function sess_update()
	{
	// We only update the session every five minutes by default
	if (($this->userdata['last_activity'] + $this->sess_time_to_update) >= $this->now)
	{
	return;
	}

	// Save the old session id so we know which record to
	// update in the database if we need it
	$old_sessid = $this->userdata['session_id'];
	$new_sessid = '';
	while (strlen($new_sessid) < 32)
	{
	$new_sessid .= mt_rand(0, mt_getrandmax());
	}

	// 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
	$new_sessid = md5(uniqid($new_sessid, TRUE));

	// Update the session data in the session data array
	$this->userdata['session_id'] = $new_sessid;
	$this->userdata['last_activity'] = $this->now;

	// _set_cookie() will handle this for us if we aren't using database sessions
	// by pushing all userdata to the cookie.
	$cookie_data = NULL;

	// Update the session ID and last_activity field in the DB if needed
	if ($this->sess_use_database === TRUE)
	{
	// set cookie explicitly to only have our session data
	$cookie_data = array();
	foreach (array('session_id','ip_address','user_agent','last_activity') as $val)
	{
	$cookie_data[$val] = $this->userdata[$val];
	}

	$this->CI->db->query($this->CI->db->update_string($this->sess_table_name, array('last_activity' => $this->now, 'session_id' => $new_sessid), array('session_id' => $old_sessid)));
	}

	// Write the cookie
	$this->_set_cookie($cookie_data);
	}

	// --------------------------------------------------------------------

	/**
	* Destroy the current session
	*
	* @access public
	* @return void
	*/
	function sess_destroy()
	{
	// Kill the session DB row
	if ($this->sess_use_database === TRUE AND isset($this->userdata['session_id']))
	{
	$this->CI->db->where('session_id', $this->userdata['session_id']);
	$this->CI->db->delete($this->sess_table_name);
	}

	// Kill the cookie
	setcookie(
	$this->sess_cookie_name,
	addslashes(serialize(array())),
	($this->now - 31500000),
	$this->cookie_path,
	$this->cookie_domain,
	0
	);
	}

	// --------------------------------------------------------------------

	/**
	* Fetch a specific item from the session array
	*
	* @access public
	* @param string
	* @return string
	*/
	function userdata($item)
	{
	return ( ! isset($this->userdata[$item])) ? FALSE : $this->userdata[$item];
	}

	// --------------------------------------------------------------------

	/**
	* Fetch all session data
	*
	* @access public
	* @return array
	*/
	function all_userdata()
	{
	return $this->userdata;
	}

	// --------------------------------------------------------------------

	/**
	* Add or change data in the "userdata" array
	*
	* @access public
	* @param mixed
	* @param string
	* @return void
	*/
	function set_userdata($newdata = array(), $newval = '')
	{
	if (is_string($newdata))
	{
	$newdata = array($newdata => $newval);
	}

	if (count($newdata) > 0)
	{
	foreach ($newdata as $key => $val)
	{
	$this->userdata[$key] = $val;
	}
	}

	$this->sess_write();
	}

	// --------------------------------------------------------------------

	/**
	* Delete a session variable from the "userdata" array
	*
	* @access array
	* @return void
	*/
	function unset_userdata($newdata = array())
	{
	if (is_string($newdata))
	{
	$newdata = array($newdata => '');
	}

	if (count($newdata) > 0)
	{
	foreach ($newdata as $key => $val)
	{
	unset($this->userdata[$key]);
	}
	}

	$this->sess_write();
	}

	// ------------------------------------------------------------------------

	/**
	* Add or change flashdata, only available
	* until the next request
	*
	* @access public
	* @param mixed
	* @param string
	* @return void
	*/
	function set_flashdata($newdata = array(), $newval = '')
	{
	if (is_string($newdata))
	{
	$newdata = array($newdata => $newval);
	}

	if (count($newdata) > 0)
	{
	foreach ($newdata as $key => $val)
	{
	$flashdata_key = $this->flashdata_key.':new:'.$key;
	$this->set_userdata($flashdata_key, $val);
	}
	}
	}

	// ------------------------------------------------------------------------

	/**
	* Keeps existing flashdata available to next request.
	*
	* @access public
	* @param string
	* @return void
	*/
	function keep_flashdata($key)
	{
	// 'old' flashdata gets removed. Here we mark all
	// flashdata as 'new' to preserve it from _flashdata_sweep()
	// Note the function will return FALSE if the $key
	// provided cannot be found
	$old_flashdata_key = $this->flashdata_key.':old:'.$key;
	$value = $this->userdata($old_flashdata_key);

	$new_flashdata_key = $this->flashdata_key.':new:'.$key;
	$this->set_userdata($new_flashdata_key, $value);
	}

	// ------------------------------------------------------------------------

	/**
	* Fetch a specific flashdata item from the session array
	*
	* @access public
	* @param string
	* @return string
	*/
	function flashdata($key)
	{
	$flashdata_key = $this->flashdata_key.':old:'.$key;
	return $this->userdata($flashdata_key);
	}

	// ------------------------------------------------------------------------

	/**
	* Identifies flashdata as 'old' for removal
	* when _flashdata_sweep() runs.
	*
	* @access private
	* @return void
	*/
	function _flashdata_mark()
	{
	$userdata = $this->all_userdata();
	foreach ($userdata as $name => $value)
	{
	$parts = explode(':new:', $name);
	if (is_array($parts) && count($parts) === 2)
	{
	$new_name = $this->flashdata_key.':old:'.$parts[1];
	$this->set_userdata($new_name, $value);
	$this->unset_userdata($name);
	}
	}
	}

	// ------------------------------------------------------------------------

	/**
	* Removes all flashdata marked as 'old'
	*
	* @access private
	* @return void
	*/

	function _flashdata_sweep()
	{
	$userdata = $this->all_userdata();
	foreach ($userdata as $key => $value)
	{
	if (strpos($key, ':old:'))
	{
	$this->unset_userdata($key);
	}
	}

	}

	// --------------------------------------------------------------------

	/**
	* Get the "now" time
	*
	* @access private
	* @return string
	*/
	function _get_time()
	{
	if (strtolower($this->time_reference) == 'gmt')
	{
	$now = time();
	$time = mktime(gmdate("H", $now), gmdate("i", $now), gmdate("s", $now), gmdate("m", $now), gmdate("d", $now), gmdate("Y", $now));
	}
	else
	{
	$time = time();
	}

	return $time;
	}

	// --------------------------------------------------------------------

	/**
	* Write the session cookie
	*
	* @access public
	* @return void
	*/
	function _set_cookie($cookie_data = NULL)
	{
	if (is_null($cookie_data))
	{
	$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
	setcookie(
	$this->sess_cookie_name,
	$cookie_data,
	$expire,
	$this->cookie_path,
	$this->cookie_domain,
	$this->cookie_secure
	);
	}

	// --------------------------------------------------------------------

	/**
	* 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 private
	* @param array
	* @return string
	*/
	function _serialize($data)
	{
	if (is_array($data))
	{
	array_walk_recursive($data, array(&$this, '_escape_slashes'));
	}
	else
	{
	if (is_string($data))
	{
	$data = str_replace('\\', '{{slash}}', $data);
	}
	}
	return serialize($data);
	}

	/**
	* Escape slashes
	*
	* This function converts any slashes found into a temporary marker
	*
	* @access private
	*/
	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 private
	* @param array
	* @return string
	*/
	function _unserialize($data)
	{
	$data = @unserialize(strip_slashes($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 private
	*/
	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 public
	* @return void
	*/
	function _sess_gc()
	{
	if ($this->sess_use_database != TRUE)
	{
	return;
	}

	srand(time());
	if ((rand() % 100) < $this->gc_probability)
	{
	$expire = $this->now - $this->sess_expiration;

	$this->CI->db->where("last_activity < {$expire}");
	$this->CI->db->delete($this->sess_table_name);

	log_message('debug', 'Session garbage collection performed.');
	}
	}


	}
	// END Session Class

	/* End of file Session.php */
	/* Location: ./system/libraries/Session.php */