Merge remote-tracking branch 'upstream/develop' into develop

6 files changed, 1507 insertions, 1073 deletions

diff --git a/system/libraries/Session/drivers/Session_cookie.php b/system/libraries/Session/drivers/Session_cookie.php
deleted file mode 100644
index c0e62affa..000000000
--- a/system/libraries/Session/drivers/Session_cookie.php
+++ /dev/null
@@ -1,816 +0,0 @@
-<?php
-/**
- * CodeIgniter
- *
- * An open source application development framework for PHP
- *
- * This content is released under the MIT License (MIT)
- *
- * Copyright (c) 2014 - 2015, British Columbia Institute of Technology
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to deal
- * in the Software without restriction, including without limitation the rights
- * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
- * THE SOFTWARE.
- *
- * @package	CodeIgniter
- * @author	EllisLab Dev Team
- * @copyright	Copyright (c) 2008 - 2014, EllisLab, Inc. (http://ellislab.com/)
- * @copyright	Copyright (c) 2014 - 2015, British Columbia Institute of Technology (http://bcit.ca/)
- * @license	http://opensource.org/licenses/MIT	MIT License
- * @link	http://codeigniter.com
- * @since	Version 1.0.0
- * @filesource
- */
-defined('BASEPATH') OR exit('No direct script access allowed');
-
-/**
- * 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();
-
-	/**
-	 * 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;
-
-	/**
-	 * Standardize newlines flag
-	 *
-	 * @var	bool
-	 */
-	protected $_standardize_newlines;
-
-	// ------------------------------------------------------------------------
-
-	/**
-	 * Initialize session driver object
-	 *
-	 * @return	void
-	 */
-	protected function initialize()
-	{
-		// 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',
-		);
-
-		$this->_standardize_newlines = (bool) config_item('standardize_newlines');
-
-		foreach ($prefs as $key)
-		{
-			$this->$key = isset($this->_parent->params[$key])
-				? $this->_parent->params[$key]
-				: $this->CI->config->item($key);
-		}
-
-		if (empty($this->encryption_key))
-		{
-			show_error('In order to use the Cookie Session driver you are required to set an encryption key in your config file.');
-		}
-
-		// Do we need encryption? If so, load the encryption class
-		if ($this->sess_encrypt_cookie === TRUE)
-		{
-			$this->CI->load->library('encryption');
-		}
-
-		// Check for database
-		if ($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']));
-			$this->data_dirty = FALSE;
-		}
-
-		// Kill the cookie
-		$this->_setcookie($this->sess_cookie_name, '', ($this->now - 31500000),
-			$this->cookie_path, $this->cookie_domain, 0);
-
-		// Kill session data
-		$this->userdata = array();
-	}
-
-	// ------------------------------------------------------------------------
-
-	/**
-	 * Regenerate the current session
-	 *
-	 * Regenerate the session id
-	 *
-	 * @param	bool	Destroy session data flag (default: false)
-	 * @return	void
-	 */
-	public function sess_regenerate($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 $this->userdata;
-	}
-
-	// ------------------------------------------------------------------------
-
-	/**
-	 * Fetch the current session data if it exists
-	 *
-	 * @return	bool
-	 */
-	protected function _sess_read()
-	{
-		// Fetch the cookie
-		$session = $this->CI->input->cookie($this->sess_cookie_name);
-
-		// No cookie? Goodbye cruel world!...
-		if ($session === NULL)
-		{
-			log_message('debug', 'A session cookie was not found.');
-			return FALSE;
-		}
-
-		if ($this->sess_encrypt_cookie === TRUE)
-		{
-			$session = $this->CI->encryption->decrypt($session);
-			if ($session === FALSE)
-			{
-				log_message('error', 'Session: Unable to decrypt the session cookie, possibly due to a HMAC mismatch.');
-				return FALSE;
-			}
-		}
-		else
-		{
-			if (($len = strlen($session) - 40) <= 0)
-			{
-				log_message('error', 'Session: The session cookie was not signed.');
-				return FALSE;
-			}
-
-			// Check cookie authentication
-			$hmac = substr($session, $len);
-			$session = substr($session, 0, $len);
-
-			// Time-attack-safe comparison
-			$hmac_check = hash_hmac('sha1', $session, $this->encryption_key);
-			$diff = 0;
-			for ($i = 0; $i < 40; $i++)
-			{
-				$diff |= ord($hmac[$i]) ^ ord($hmac_check[$i]);
-			}
-
-			if ($diff !== 0)
-			{
-				log_message('error', 'Session: HMAC mismatch. The session cookie data did not match what was expected.');
-				$this->sess_destroy();
-				return FALSE;
-			}
-		}
-
-		// Unserialize the session array
-		$session = @unserialize($session);
-
-		// Is the session data we unserialized an array with the correct format?
-		if ( ! is_array($session) OR ! isset($session['session_id'], $session['ip_address'], $session['user_agent'], $session['last_activity']))
-		{
-			log_message('debug', 'Session: Wrong cookie data format');
-			$this->sess_destroy();
-			return FALSE;
-		}
-
-		// Is the session current?
-		if (($session['last_activity'] + $this->sess_expiration) < $this->now OR $session['last_activity'] > $this->now)
-		{
-			log_message('debug', 'Session: Expired');
-			$this->sess_destroy();
-			return FALSE;
-		}
-
-		// Does the IP match?
-		if ($this->sess_match_ip === TRUE && $session['ip_address'] !== $this->CI->input->ip_address())
-		{
-			log_message('debug', 'Session: IP address mismatch');
-			$this->sess_destroy();
-			return FALSE;
-		}
-
-		// Does the User Agent Match?
-		if ($this->sess_match_useragent === TRUE &&
-			trim($session['user_agent']) !== trim(substr($this->CI->input->user_agent(), 0, 120)))
-		{
-			log_message('debug', 'Session: User Agent string mismatch');
-			$this->sess_destroy();
-			return FALSE;
-		}
-
-		// Is there a corresponding session in the DB?
-		if ($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']);
-			}
-
-			// Is caching in effect? Turn it off
-			$db_cache = $this->CI->db->cache_on;
-			$this->CI->db->cache_off();
-
-			$query = $this->CI->db->get($this->sess_table_name);
-
-			// Was caching in effect?
-			if ($db_cache)
-			{
-				// Turn it back on
-				$this->CI->db->cache_on();
-			}
-
-			// No result? Kill it!
-			if (empty($query) OR $query->num_rows() === 0)
-			{
-				log_message('debug', 'Session: No match found in our database');
-				$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))
-			{
-				$custom_data = unserialize(trim($row->user_data));
-
-				if (is_array($custom_data))
-				{
-					$session = $session + $custom_data;
-				}
-			}
-		}
-
-		// Session is valid!
-		$this->userdata = $session;
-		return TRUE;
-	}
-
-	// ------------------------------------------------------------------------
-
-	/**
-	 * Create a new session
-	 *
-	 * @return	void
-	 */
-	protected function _sess_create()
-	{
-		// Initialize userdata
-		$this->userdata = array(
-			'session_id'	=> $this->_make_sess_id(),
-			'ip_address'	=> $this->CI->input->ip_address(),
-			'user_agent'	=> trim(substr($this->CI->input->user_agent(), 0, 120)),
-			'last_activity'	=> $this->now,
-		);
-
-		log_message('debug', 'Session: Creating new session ('.$this->userdata['session_id'].')');
-
-		// 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
-		$this->_set_cookie();
-	}
-
-	// ------------------------------------------------------------------------
-
-	/**
-	 * Update an existing session
-	 *
-	 * @param	bool	Force update flag (default: false)
-	 * @return	void
-	 */
-	protected function _sess_update($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'] = $this->_make_sess_id();
-
-			log_message('debug', 'Session: Regenerate ID');
-		}
-
-		// Check for database
-		if ($this->sess_use_database === TRUE)
-		{
-			$this->CI->db->where('session_id', $old_sessid);
-
-			if ($this->sess_match_ip === TRUE)
-			{
-				$this->CI->db->where('ip_address', $this->CI->input->ip_address());
-			}
-
-			if ($this->sess_match_useragent === TRUE)
-			{
-				$this->CI->db->where('user_agent', trim(substr($this->CI->input->user_agent(), 0, 120)));
-			}
-
-			// 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']
-				)
-			);
-		}
-
-		// Write the cookie
-		$this->_set_cookie();
-	}
-
-	// ------------------------------------------------------------------------
-
-	/**
-	 * Update database with current data
-	 *
-	 * This gets called from the shutdown function and also
-	 * registered with PHP to run at the end of the request
-	 * so it's guaranteed to update even when a fatal error
-	 * occurs. The first call makes the update and clears the
-	 * dirty flag so it won't happen twice.
-	 *
-	 * @return	void
-	 */
-	public function _update_db()
-	{
-		// Check for database and dirty flag and unsaved
-		if ($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
-				$set['user_data'] = serialize($userdata);
-			}
-
-			// Reset query builder values.
-			$this->CI->db->reset_query();
-
-			// 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->where('session_id', $this->userdata['session_id']);
-
-			if ($this->sess_match_ip === TRUE)
-			{
-				$this->CI->db->where('ip_address', $this->CI->input->ip_address());
-			}
-
-			if ($this->sess_match_useragent === TRUE)
-			{
-				$this->CI->db->where('user_agent', trim(substr($this->CI->input->user_agent(), 0, 120)));
-			}
-
-			$this->CI->db->update($this->sess_table_name, $set);
-
-			// 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
-		{
-			$new_sessid .= mt_rand();
-		}
-		while (strlen($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
-	 *
-	 * @return	int	 Time
-	 */
-	protected function _get_time()
-	{
-		if ($this->time_reference === 'local' OR $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
-	 *
-	 * @return	void
-	 */
-	protected function _set_cookie()
-	{
-		// Get userdata (only defaults if database)
-		$cookie_data = ($this->sess_use_database === TRUE)
-				? array_intersect_key($this->userdata, $this->defaults)
-				: $this->userdata;
-
-		// The Input class will do this and since we use HMAC verification,
-		// unless we standardize here as well, the hash won't match.
-		if ($this->_standardize_newlines)
-		{
-			foreach (array_keys($this->userdata) as $key)
-			{
-				$this->userdata[$key] = preg_replace('/(?:\r\n|[\r\n])/', PHP_EOL, $this->userdata[$key]);
-			}
-		}
-
-		// Serialize the userdata for the cookie
-		$cookie_data = serialize($cookie_data);
-
-		if ($this->sess_encrypt_cookie === TRUE)
-		{
-			$cookie_data = $this->CI->encryption->encrypt($cookie_data);
-		}
-		else
-		{
-			// Require message authentication
-			$cookie_data .= hash_hmac('sha1', $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, $this->cookie_httponly);
-	}
-
-	// ------------------------------------------------------------------------
-
-	/**
-	 * Set a cookie with the system
-	 *
-	 * This abstraction of the setcookie call allows overriding for unit testing
-	 *
-	 * @param	string	Cookie name
-	 * @param	string	Cookie value
-	 * @param	int	Expiration time
-	 * @param	string	Cookie path
-	 * @param	string	Cookie domain
-	 * @param	bool	Secure connection flag
-	 * @param	bool	HTTP protocol only flag
-	 * @return	void
-	 */
-	protected function _setcookie($name, $value = '', $expire = 0, $path = '', $domain = '', $secure = FALSE, $httponly = FALSE)
-	{
-		setcookie($name, $value, $expire, $path, $domain, $secure, $httponly);
-	}
-
-	// ------------------------------------------------------------------------
-
-	/**
-	 * Garbage collection
-	 *
-	 * This deletes expired session rows from database
-	 * if the probability percentage is met
-	 *
-	 * @return	void
-	 */
-	protected function _sess_gc()
-	{
-		if ($this->sess_use_database !== TRUE)
-		{
-			return;
-		}
-
-		$probability = ini_get('session.gc_probability');
-		$divisor = ini_get('session.gc_divisor');
-
-		if (mt_rand(1, $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 */
\ No newline at end of file
diff --git a/system/libraries/Session/drivers/Session_database_driver.php b/system/libraries/Session/drivers/Session_database_driver.php
new file mode 100644
index 000000000..0ec6e34f0
--- /dev/null
+++ b/system/libraries/Session/drivers/Session_database_driver.php
@@ -0,0 +1,385 @@
+<?php
+/**
+ * CodeIgniter
+ *
+ * An open source application development framework for PHP
+ *
+ * This content is released under the MIT License (MIT)
+ *
+ * Copyright (c) 2014 - 2015, British Columbia Institute of Technology
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ *
+ * @package	CodeIgniter
+ * @author	EllisLab Dev Team
+ * @copyright	Copyright (c) 2008 - 2014, EllisLab, Inc. (http://ellislab.com/)
+ * @copyright	Copyright (c) 2014 - 2015, British Columbia Institute of Technology (http://bcit.ca/)
+ * @license	http://opensource.org/licenses/MIT	MIT License
+ * @link	http://codeigniter.com
+ * @since	Version 3.0.0
+ * @filesource
+ */
+defined('BASEPATH') OR exit('No direct script access allowed');
+
+/**
+ * CodeIgniter Session Database Driver
+ *
+ * @package	CodeIgniter
+ * @subpackage	Libraries
+ * @category	Sessions
+ * @author	Andrey Andreev
+ * @link	http://codeigniter.com/user_guide/libraries/sessions.html
+ */
+class CI_Session_database_driver extends CI_Session_driver implements SessionHandlerInterface {
+
+	/**
+	 * DB object
+	 *
+	 * @var	object
+	 */
+	protected $_db;
+
+	/**
+	 * Row exists flag
+	 *
+	 * @var	bool
+	 */
+	protected $_row_exists = FALSE;
+
+	/**
+	 * Lock "driver" flag
+	 *
+	 * @var	string
+	 */
+	protected $_platform;
+
+	// ------------------------------------------------------------------------
+
+	/**
+	 * Class constructor
+	 *
+	 * @param	array	$params	Configuration parameters
+	 * @return	void
+	 */
+	public function __construct(&$params)
+	{
+		parent::__construct($params);
+
+		$CI =& get_instance();
+		isset($CI->db) OR $CI->load->database();
+		$this->_db = $CI->db;
+
+		if ( ! $this->_db instanceof CI_DB_query_builder)
+		{
+			throw new Exception('Query Builder not enabled for the configured database. Aborting.');
+		}
+		elseif ($this->_db->pconnect)
+		{
+			throw new Exception('Configured database connection is persistent. Aborting.');
+		}
+
+		$db_driver = $this->_db->dbdriver.(empty($this->_db->subdriver) ? '' : '_'.$this->_db->subdriver);
+		if (strpos($db_driver, 'mysql') !== FALSE)
+		{
+			$this->_platform = 'mysql';
+		}
+		elseif (in_array($db_driver, array('postgre', 'pdo_pgsql'), TRUE))
+		{
+			$this->_platform = 'postgre';
+		}
+
+		// Note: BC work-around for the old 'sess_table_name' setting, should be removed in the future.
+		isset($this->_config['save_path']) OR $this->_config['save_path'] = config_item('sess_table_name');
+	}
+
+	// ------------------------------------------------------------------------
+
+	/**
+	 * Open
+	 *
+	 * Initializes the database connection
+	 *
+	 * @param	string	$save_path	Table name
+	 * @param	string	$name		Session cookie name, unused
+	 * @return	bool
+	 */
+	public function open($save_path, $name)
+	{
+		return empty($this->_db->conn_id)
+			? ( ! $this->_db->autoinit && $this->_db->db_connect())
+			: TRUE;
+	}
+
+	// ------------------------------------------------------------------------
+
+	/**
+	 * Read
+	 *
+	 * Reads session data and acquires a lock
+	 *
+	 * @param	string	$session_id	Session ID
+	 * @return	string	Serialized session data
+	 */
+	public function read($session_id)
+	{
+		if ($this->_get_lock($session_id) !== FALSE)
+		{
+			// Needed by write() to detect session_regenerate_id() calls
+			$this->_session_id = $session_id;
+
+			$this->_db
+				->select('data')
+				->from($this->_config['save_path'])
+				->where('id', $session_id);
+
+			if ($this->_config['match_ip'])
+			{
+				$this->_db->where('ip_address', $_SERVER['REMOTE_ADDR']);
+			}
+
+			if (($result = $this->_db->get()->row()) === NULL)
+			{
+				$this->_fingerprint = md5('');
+				return '';
+			}
+
+			// PostgreSQL's variant of a BLOB datatype is Bytea, which is a
+			// PITA to work with, so we use base64-encoded data in a TEXT
+			// field instead.
+			$result = ($this->_platform === 'postgre')
+				? base64_decode(rtrim($result->data))
+				: $result->data;
+
+			$this->_fingerprint = md5($result);
+			$this->_row_exists = TRUE;
+			return $result;
+		}
+
+		$this->_fingerprint = md5('');
+		return '';
+	}
+
+	// ------------------------------------------------------------------------
+
+	/**
+	 * Write
+	 *
+	 * Writes (create / update) session data
+	 *
+	 * @param	string	$session_id	Session ID
+	 * @param	string	$session_data	Serialized session data
+	 * @return	bool
+	 */
+	public function write($session_id, $session_data)
+	{
+		// Was the ID regenerated?
+		if ($session_id !== $this->_session_id)
+		{
+			if ( ! $this->_release_lock() OR ! $this->_get_lock($session_id))
+			{
+				return FALSE;
+			}
+
+			$this->_row_exists = FALSE;
+			$this->_session_id = $session_id;
+		}
+		elseif ($this->_lock === FALSE)
+		{
+			return FALSE;
+		}
+
+		if ($this->_row_exists === FALSE)
+		{
+			$insert_data = array(
+				'id' => $session_id,
+				'ip_address' => $_SERVER['REMOTE_ADDR'],
+				'timestamp' => time(),
+				'data' => ($this->_platform === 'postgre' ? base64_encode($session_data) : $session_data)
+			);
+
+			if ($this->_db->insert($this->_config['save_path'], $insert_data))
+			{
+				$this->_fingerprint = md5($session_data);
+				return $this->_row_exists = TRUE;
+			}
+
+			return FALSE;
+		}
+
+		$this->_db->where('id', $session_id);
+		if ($this->_config['match_ip'])
+		{
+			$this->_db->where('ip_address', $_SERVER['REMOTE_ADDR']);
+		}
+
+		$update_data = array('timestamp' => time());
+		if ($this->_fingerprint !== md5($session_data))
+		{
+			$update_data['data'] = ($this->_platform === 'postgre')
+				? base64_encode($session_data)
+				: $session_data;
+		}
+
+		if ($this->_db->update($this->_config['save_path'], $update_data))
+		{
+			$this->_fingerprint = md5($session_data);
+			return TRUE;
+		}
+
+		return FALSE;
+	}
+
+	// ------------------------------------------------------------------------
+
+	/**
+	 * Close
+	 *
+	 * Releases locks
+	 *
+	 * @return	void
+	 */
+	public function close()
+	{
+		return ($this->_lock)
+			? $this->_release_lock()
+			: TRUE;
+	}
+
+	// ------------------------------------------------------------------------
+
+	/**
+	 * Destroy
+	 *
+	 * Destroys the current session.
+	 *
+	 * @param	string	$session_id	Session ID
+	 * @return	bool
+	 */
+	public function destroy($session_id)
+	{
+		if ($this->_lock)
+		{
+			$this->_db->where('id', $session_id);
+			if ($this->_config['match_ip'])
+			{
+				$this->_db->where('ip_address', $_SERVER['REMOTE_ADDR']);
+			}
+
+			return $this->_db->delete($this->_config['save_path'])
+				? ($this->close() && $this->_cookie_destroy())
+				: FALSE;
+		}
+
+		return ($this->close() && $this->_cookie_destroy());
+	}
+
+	// ------------------------------------------------------------------------
+
+	/**
+	 * Garbage Collector
+	 *
+	 * Deletes expired sessions
+	 *
+	 * @param	int 	$maxlifetime	Maximum lifetime of sessions
+	 * @return	bool
+	 */
+	public function gc($maxlifetime)
+	{
+		return $this->_db->delete($this->_config['save_path'], 'timestamp < '.(time() - $maxlifetime));
+	}
+
+	// ------------------------------------------------------------------------
+
+	/**
+	 * Get lock
+	 *
+	 * Acquires a lock, depending on the underlying platform.
+	 *
+	 * @param	string	$session_id	Session ID
+	 * @return	bool
+	 */
+	protected function _get_lock($session_id)
+	{
+		if ($this->_platform === 'mysql')
+		{
+			$arg = $session_id.($this->_config['match_ip'] ? '_'.$_SERVER['REMOTE_ADDR'] : '');
+			if ($this->_db->query("SELECT GET_LOCK('".$arg."', 10) AS ci_session_lock")->row()->ci_session_lock)
+			{
+				$this->_lock = $arg;
+				return TRUE;
+			}
+
+			return FALSE;
+		}
+		elseif ($this->_platform === 'postgre')
+		{
+			$arg = "hashtext('".$session_id."')".($this->_config['match_ip'] ? ", hashtext('".$_SERVER['REMOTE_ADDR']."')" : '');
+			if ($this->_db->simple_query('SELECT pg_advisory_lock('.$arg.')'))
+			{
+				$this->_lock = $arg;
+				return TRUE;
+			}
+
+			return FALSE;
+		}
+
+		return parent::_get_lock($session_id);
+	}
+
+	// ------------------------------------------------------------------------
+
+	/**
+	 * Release lock
+	 *
+	 * Releases a previously acquired lock
+	 *
+	 * @return	bool
+	 */
+	protected function _release_lock()
+	{
+		if ( ! $this->_lock)
+		{
+			return TRUE;
+		}
+
+		if ($this->_platform === 'mysql')
+		{
+			if ($this->_db->query("SELECT RELEASE_LOCK('".$this->_lock."') AS ci_session_lock")->row()->ci_session_lock)
+			{
+				$this->_lock = FALSE;
+				return TRUE;
+			}
+
+			return FALSE;
+		}
+		elseif ($this->_platform === 'postgre')
+		{
+			if ($this->_db->simple_query('SELECT pg_advisory_unlock('.$this->_lock.')'))
+			{
+				$this->_lock = FALSE;
+				return TRUE;
+			}
+
+			return FALSE;
+		}
+
+		return parent::_release_lock();
+	}
+
+}
diff --git a/system/libraries/Session/drivers/Session_files_driver.php b/system/libraries/Session/drivers/Session_files_driver.php
new file mode 100644
index 000000000..ad8315d52
--- /dev/null
+++ b/system/libraries/Session/drivers/Session_files_driver.php
@@ -0,0 +1,352 @@
+<?php
+/**
+ * CodeIgniter
+ *
+ * An open source application development framework for PHP
+ *
+ * This content is released under the MIT License (MIT)
+ *
+ * Copyright (c) 2014 - 2015, British Columbia Institute of Technology
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ *
+ * @package	CodeIgniter
+ * @author	EllisLab Dev Team
+ * @copyright	Copyright (c) 2008 - 2014, EllisLab, Inc. (http://ellislab.com/)
+ * @copyright	Copyright (c) 2014 - 2015, British Columbia Institute of Technology (http://bcit.ca/)
+ * @license	http://opensource.org/licenses/MIT	MIT License
+ * @link	http://codeigniter.com
+ * @since	Version 3.0.0
+ * @filesource
+*/
+defined('BASEPATH') OR exit('No direct script access allowed');
+
+/**
+ * CodeIgniter Session Files Driver
+ *
+ * @package	CodeIgniter
+ * @subpackage	Libraries
+ * @category	Sessions
+ * @author	Andrey Andreev
+ * @link	http://codeigniter.com/user_guide/libraries/sessions.html
+ */
+class CI_Session_files_driver extends CI_Session_driver implements SessionHandlerInterface {
+
+	/**
+	 * Save path
+	 *
+	 * @var	string
+	 */
+	protected $_save_path;
+
+	/**
+	 * File handle
+	 *
+	 * @var	resource
+	 */
+	protected $_file_handle;
+
+	/**
+	 * File name
+	 *
+	 * @var	resource
+	 */
+	protected $_file_path;
+
+	/**
+	 * File new flag
+	 *
+	 * @var	bool
+	 */
+	protected $_file_new;
+
+	// ------------------------------------------------------------------------
+
+	/**
+	 * Class constructor
+	 *
+	 * @param	array	$params	Configuration parameters
+	 * @return	void
+	 */
+	public function __construct(&$params)
+	{
+		parent::__construct($params);
+
+		if (isset($this->_config['save_path']))
+		{
+			$this->_config['save_path'] = rtrim($this->_config['save_path'], '/\\');
+			ini_set('session.save_path', $this->_config['save_path']);
+		}
+		else
+		{
+			$this->_config['save_path'] = rtrim(ini_get('session.save_path'), '/\\');
+		}
+	}
+
+	// ------------------------------------------------------------------------
+
+	/**
+	 * Open
+	 *
+	 * Sanitizes the save_path directory.
+	 *
+	 * @param	string	$save_path	Path to session files' directory
+	 * @param	string	$name		Session cookie name, unused
+	 * @return	bool
+	 */
+	public function open($save_path, $name)
+	{
+		if ( ! is_dir($save_path))
+		{
+			if ( ! mkdir($save_path, 0700, TRUE))
+			{
+				throw new Exception("Session: Configured save path '".$this->_config['save_path']."' is not a directory, doesn't exist or cannot be created.");
+			}
+		}
+		elseif ( ! is_writable($save_path))
+		{
+			throw new Exception("Session: Configured save path '".$this->_config['save_path']."' is not writable by the PHP process.");
+		}
+
+		$this->_config['save_path'] = $save_path;
+		$this->_file_path = $this->_config['save_path'].DIRECTORY_SEPARATOR
+			.$name // we'll use the session cookie name as a prefix to avoid collisions
+			.($this->_config['match_ip'] ? md5($_SERVER['REMOTE_ADDR']) : '');
+
+		return TRUE;
+	}
+
+	// ------------------------------------------------------------------------
+
+	/**
+	 * Read
+	 *
+	 * Reads session data and acquires a lock
+	 *
+	 * @param	string	$session_id	Session ID
+	 * @return	string	Serialized session data
+	 */
+	public function read($session_id)
+	{
+		// This might seem weird, but PHP 5.6 introduces session_reset(),
+		// which re-reads session data
+		if ($this->_file_handle === NULL)
+		{
+			// Just using fopen() with 'c+b' mode would be perfect, but it is only
+			// available since PHP 5.2.6 and we have to set permissions for new files,
+			// so we'd have to hack around this ...
+			if (($this->_file_new = ! file_exists($this->_file_path.$session_id)) === TRUE)
+			{
+				if (($this->_file_handle = fopen($this->_file_path.$session_id, 'w+b')) === FALSE)
+				{
+					log_message('error', "Session: File '".$this->_file_path.$session_id."' doesn't exist and cannot be created.");
+					return FALSE;
+				}
+			}
+			elseif (($this->_file_handle = fopen($this->_file_path.$session_id, 'r+b')) === FALSE)
+			{
+				log_message('error', "Session: Unable to open file '".$this->_file_path.$session_id."'.");
+				return FALSE;
+			}
+
+			if (flock($this->_file_handle, LOCK_EX) === FALSE)
+			{
+				log_message('error', "Session: Unable to obtain lock for file '".$this->_file_path.$session_id."'.");
+				fclose($this->_file_handle);
+				$this->_file_handle = NULL;
+				return FALSE;
+			}
+
+			// Needed by write() to detect session_regenerate_id() calls
+			$this->_session_id = $session_id;
+
+			if ($this->_file_new)
+			{
+				chmod($this->_file_path.$session_id, 0600);
+				$this->_fingerprint = md5('');
+				return '';
+			}
+		}
+		else
+		{
+			rewind($this->_file_handle);
+		}
+
+		$session_data = '';
+		for ($read = 0, $length = filesize($this->_file_path.$session_id); $read < $length; $read += strlen($buffer))
+		{
+			if (($buffer = fread($this->_file_handle, $length - $read)) === FALSE)
+			{
+				break;
+			}
+
+			$session_data .= $buffer;
+		}
+
+		$this->_fingerprint = md5($session_data);
+		return $session_data;
+	}
+
+	// ------------------------------------------------------------------------
+
+	/**
+	 * Write
+	 *
+	 * Writes (create / update) session data
+	 *
+	 * @param	string	$session_id	Session ID
+	 * @param	string	$session_data	Serialized session data
+	 * @return	bool
+	 */
+	public function write($session_id, $session_data)
+	{
+		// If the two IDs don't match, we have a session_regenerate_id() call
+		// and we need to close the old handle and open a new one
+		if ($session_id !== $this->_session_id && ( ! $this->close() OR $this->read($session_id) === FALSE))
+		{
+			return FALSE;
+		}
+
+		if ( ! is_resource($this->_file_handle))
+		{
+			return FALSE;
+		}
+		elseif ($this->_fingerprint === md5($session_data))
+		{
+			return ($this->_file_new)
+				? TRUE
+				: touch($this->_file_path.$session_id);
+		}
+
+		if ( ! $this->_file_new)
+		{
+			ftruncate($this->_file_handle, 0);
+			rewind($this->_file_handle);
+		}
+
+		if (($length = strlen($session_data)) > 0)
+		{
+			for ($written = 0; $written < $length; $written += $result)
+			{
+				if (($result = fwrite($this->_file_handle, substr($session_data, $written))) === FALSE)
+				{
+					break;
+				}
+			}
+
+			if ( ! is_int($result))
+			{
+				$this->_fingerprint = md5(substr($session_data, 0, $written));
+				log_message('error', 'Session: Unable to write data.');
+				return FALSE;
+			}
+		}
+
+		$this->_fingerprint = md5($session_data);
+		return TRUE;
+	}
+
+	// ------------------------------------------------------------------------
+
+	/**
+	 * Close
+	 *
+	 * Releases locks and closes file descriptor.
+	 *
+	 * @return	void
+	 */
+	public function close()
+	{
+		if (is_resource($this->_file_handle))
+		{
+			flock($this->_file_handle, LOCK_UN);
+			fclose($this->_file_handle);
+
+			$this->_file_handle = $this->_file_new = $this->_session_id = NULL;
+			return TRUE;
+		}
+
+		return TRUE;
+	}
+
+	// ------------------------------------------------------------------------
+
+	/**
+	 * Destroy
+	 *
+	 * Destroys the current session.
+	 *
+	 * @param	string	$session_id	Session ID
+	 * @return	bool
+	 */
+	public function destroy($session_id)
+	{
+		if ($this->close())
+		{
+			return unlink($this->_file_path.$session_id) && $this->_cookie_destroy();
+		}
+		elseif ($this->_file_path !== NULL)
+		{
+			clearstatcache();
+			return file_exists($this->_file_path.$session_id)
+				? (unlink($this->_file_path.$session_id) && $this->_cookie_destroy())
+				: TRUE;
+		}
+
+		return FALSE;
+	}
+
+	// ------------------------------------------------------------------------
+
+	/**
+	 * Garbage Collector
+	 *
+	 * Deletes expired sessions
+	 *
+	 * @param	int 	$maxlifetime	Maximum lifetime of sessions
+	 * @return	bool
+	 */
+	public function gc($maxlifetime)
+	{
+		if ( ! is_dir($this->_config['save_path']) OR ($files = scandir($this->_config['save_path'])) === FALSE)
+		{
+			log_message('debug', "Session: Garbage collector couldn't list files under directory '".$this->_config['save_path']."'.");
+			return FALSE;
+		}
+
+		$ts = time() - $maxlifetime;
+
+		foreach ($files as $file)
+		{
+			// If the filename doesn't match this pattern, it's either not a session file or is not ours
+			if ( ! preg_match('/(?:[0-9a-f]{32})?[0-9a-f]{40}$/i', $file)
+				OR ! is_file($this->_config['save_path'].DIRECTORY_SEPARATOR.$file)
+				OR ($mtime = filemtime($this->_config['save_path'].DIRECTORY_SEPARATOR.$file)) === FALSE
+				OR $mtime > $ts)
+			{
+				continue;
+			}
+
+			unlink($this->_config['save_path'].DIRECTORY_SEPARATOR.$file);
+		}
+
+		return TRUE;
+	}
+
+}
diff --git a/system/libraries/Session/drivers/Session_memcached_driver.php b/system/libraries/Session/drivers/Session_memcached_driver.php
new file mode 100644
index 000000000..00112c88c
--- /dev/null
+++ b/system/libraries/Session/drivers/Session_memcached_driver.php
@@ -0,0 +1,375 @@
+<?php
+/**
+ * CodeIgniter
+ *
+ * An open source application development framework for PHP
+ *
+ * This content is released under the MIT License (MIT)
+ *
+ * Copyright (c) 2014 - 2015, British Columbia Institute of Technology
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ *
+ * @package	CodeIgniter
+ * @author	EllisLab Dev Team
+ * @copyright	Copyright (c) 2008 - 2014, EllisLab, Inc. (http://ellislab.com/)
+ * @copyright	Copyright (c) 2014 - 2015, British Columbia Institute of Technology (http://bcit.ca/)
+ * @license	http://opensource.org/licenses/MIT	MIT License
+ * @link	http://codeigniter.com
+ * @since	Version 3.0.0
+ * @filesource
+ */
+defined('BASEPATH') OR exit('No direct script access allowed');
+
+/**
+ * CodeIgniter Session Memcached Driver
+ *
+ * @package	CodeIgniter
+ * @subpackage	Libraries
+ * @category	Sessions
+ * @author	Andrey Andreev
+ * @link	http://codeigniter.com/user_guide/libraries/sessions.html
+ */
+class CI_Session_memcached_driver extends CI_Session_driver implements SessionHandlerInterface {
+
+	/**
+	 * Memcached instance
+	 *
+	 * @var	Memcached
+	 */
+	protected $_memcached;
+
+	/**
+	 * Key prefix
+	 *
+	 * @var	string
+	 */
+	protected $_key_prefix = 'ci_session:';
+
+	/**
+	 * Lock key
+	 *
+	 * @var	string
+	 */
+	protected $_lock_key;
+
+	// ------------------------------------------------------------------------
+
+	/**
+	 * Class constructor
+	 *
+	 * @param	array	$params	Configuration parameters
+	 * @return	void
+	 */
+	public function __construct(&$params)
+	{
+		parent::__construct($params);
+
+		if (empty($this->_config['save_path']))
+		{
+			log_message('error', 'Session: No Memcached save path configured.');
+		}
+
+		if ($this->_config['match_ip'] === TRUE)
+		{
+			$this->_key_prefix .= $_SERVER['REMOTE_ADDR'].':';
+		}
+	}
+
+	// ------------------------------------------------------------------------
+
+	/**
+	 * Open
+	 *
+	 * Sanitizes save_path and initializes connections.
+	 *
+	 * @param	string	$save_path	Server path(s)
+	 * @param	string	$name		Session cookie name, unused
+	 * @return	bool
+	 */
+	public function open($save_path, $name)
+	{
+		$this->_memcached = new Memcached();
+		$this->_memcached->setOption(Memcached::OPT_BINARY_PROTOCOL, TRUE); // required for touch() usage
+		$server_list = array();
+		foreach ($this->_memcached->getServerList() as $server)
+		{
+			$server_list[] = $server['host'].':'.$server['port'];
+		}
+
+		if ( ! preg_match_all('#,?([^,:]+)\:(\d{1,5})(?:\:(\d+))?#', $this->_config['save_path'], $matches, PREG_SET_ORDER))
+		{
+			$this->_memcached = NULL;
+			log_message('error', 'Session: Invalid Memcached save path format: '.$this->_config['save_path']);
+			return FALSE;
+		}
+
+		foreach ($matches as $match)
+		{
+			// If Memcached already has this server (or if the port is invalid), skip it
+			if (in_array($match[1].':'.$match[2], $server_list, TRUE))
+			{
+				log_message('debug', 'Session: Memcached server pool already has '.$match[1].':'.$match[2]);
+				continue;
+			}
+
+			if ( ! $this->_memcached->addServer($match[1], $match[2], isset($match[3]) ? $match[3] : 0))
+			{
+				log_message('error', 'Could not add '.$match[1].':'.$match[2].' to Memcached server pool.');
+			}
+			else
+			{
+				$server_list[] = $match[1].':'.$match[2];
+			}
+		}
+
+		if (empty($server_list))
+		{
+			log_message('error', 'Session: Memcached server pool is empty.');
+			return FALSE;
+		}
+
+		return TRUE;
+	}
+
+	// ------------------------------------------------------------------------
+
+	/**
+	 * Read
+	 *
+	 * Reads session data and acquires a lock
+	 *
+	 * @param	string	$session_id	Session ID
+	 * @return	string	Serialized session data
+	 */
+	public function read($session_id)
+	{
+		if (isset($this->_memcached) && $this->_get_lock($session_id))
+		{
+			// Needed by write() to detect session_regenerate_id() calls
+			$this->_session_id = $session_id;
+
+			$session_data = (string) $this->_memcached->get($this->_key_prefix.$session_id);
+			$this->_fingerprint = md5($session_data);
+			return $session_data;
+		}
+
+		return FALSE;
+	}
+
+	// ------------------------------------------------------------------------
+
+	/**
+	 * Write
+	 *
+	 * Writes (create / update) session data
+	 *
+	 * @param	string	$session_id	Session ID
+	 * @param	string	$session_data	Serialized session data
+	 * @return	bool
+	 */
+	public function write($session_id, $session_data)
+	{
+		if ( ! isset($this->_memcached))
+		{
+			return FALSE;
+		}
+		// Was the ID regenerated?
+		elseif ($session_id !== $this->_session_id)
+		{
+			if ( ! $this->_release_lock() OR ! $this->_get_lock($session_id))
+			{
+				return FALSE;
+			}
+
+			$this->_fingerprint = md5('');
+			$this->_session_id = $session_id;
+		}
+
+		if (isset($this->_lock_key))
+		{
+			$this->_memcached->replace($this->_lock_key, time(), 5);
+			if ($this->_fingerprint !== ($fingerprint = md5($session_data)))
+			{
+				if ($this->_memcached->set($this->_key_prefix.$session_id, $session_data, $this->_config['expiration']))
+				{
+					$this->_fingerprint = $fingerprint;
+					return TRUE;
+				}
+
+				return FALSE;
+			}
+
+			return $this->_memcached->touch($this->_key_prefix.$session_id, $this->_config['expiration']);
+		}
+
+		return FALSE;
+	}
+
+	// ------------------------------------------------------------------------
+
+	/**
+	 * Close
+	 *
+	 * Releases locks and closes connection.
+	 *
+	 * @return	void
+	 */
+	public function close()
+	{
+		if (isset($this->_memcached))
+		{
+			isset($this->_lock_key) && $this->_memcached->delete($this->_lock_key);
+			if ( ! $this->_memcached->quit())
+			{
+				return FALSE;
+			}
+
+			$this->_memcached = NULL;
+			return TRUE;
+		}
+
+		return FALSE;
+	}
+
+	// ------------------------------------------------------------------------
+
+	/**
+	 * Destroy
+	 *
+	 * Destroys the current session.
+	 *
+	 * @param	string	$session_id	Session ID
+	 * @return	bool
+	 */
+	public function destroy($session_id)
+	{
+		if (isset($this->_memcached, $this->_lock_key))
+		{
+			$this->_memcached->delete($this->_key_prefix.$session_id);
+			return $this->_cookie_destroy();
+		}
+
+		return FALSE;
+	}
+
+	// ------------------------------------------------------------------------
+
+	/**
+	 * Garbage Collector
+	 *
+	 * Deletes expired sessions
+	 *
+	 * @param	int 	$maxlifetime	Maximum lifetime of sessions
+	 * @return	bool
+	 */
+	public function gc($maxlifetime)
+	{
+		// Not necessary, Memcached takes care of that.
+		return TRUE;
+	}
+
+	// ------------------------------------------------------------------------
+
+	/**
+	 * Get lock
+	 *
+	 * Acquires an (emulated) lock.
+	 *
+	 * @param	string	$session_id	Session ID
+	 * @return	bool
+	 */
+	protected function _get_lock($session_id)
+	{
+		if (isset($this->_lock_key))
+		{
+			return $this->_memcached->replace($this->_lock_key, time(), 5);
+		}
+
+		$lock_key = $this->_key_prefix.$session_id.':lock';
+		if ( ! ($ts = $this->_memcached->get($lock_key)))
+		{
+			if ( ! $this->_memcached->set($lock_key, TRUE, 5))
+			{
+				log_message('error', 'Session: Error while trying to obtain lock for '.$this->_key_prefix.$session_id);
+				return FALSE;
+			}
+
+			$this->_lock_key = $lock_key;
+			$this->_lock = TRUE;
+			return TRUE;
+		}
+
+		// Another process has the lock, we'll try to wait for it to free itself ...
+		$attempt = 0;
+		while ($attempt++ < 5)
+		{
+			usleep(((time() - $ts) * 1000000) - 20000);
+			if (($ts = $this->_memcached->get($lock_key)) < time())
+			{
+				continue;
+			}
+
+			if ( ! $this->_memcached->set($lock_key, time(), 5))
+			{
+				log_message('error', 'Session: Error while trying to obtain lock for '.$this->_key_prefix.$session_id);
+				return FALSE;
+			}
+
+			$this->_lock_key = $lock_key;
+			break;
+		}
+
+		if ($attempt === 5)
+		{
+			log_message('error', 'Session: Unable to obtain lock for '.$this->_key_prefix.$session_id.' after 5 attempts, aborting.');
+			return FALSE;
+		}
+
+		$this->_lock = TRUE;
+		return TRUE;
+	}
+
+	// ------------------------------------------------------------------------
+
+	/**
+	 * Release lock
+	 *
+	 * Releases a previously acquired lock
+	 *
+	 * @return	bool
+	 */
+	protected function _release_lock()
+	{
+		if (isset($this->_memcached, $this->_lock_key) && $this->_lock)
+		{
+			if ( ! $this->_memcached->delete($this->_lock_key) && $this->_memcached->getResultCode() !== Memcached::RES_NOTFOUND)
+			{
+				log_message('error', 'Session: Error while trying to free lock for '.$this->_key_prefix.$session_id);
+				return FALSE;
+			}
+
+			$this->_lock_key = NULL;
+			$this->_lock = FALSE;
+		}
+
+		return TRUE;
+	}
+
+}
diff --git a/system/libraries/Session/drivers/Session_native.php b/system/libraries/Session/drivers/Session_native.php
deleted file mode 100644
index c95e7f23f..000000000
--- a/system/libraries/Session/drivers/Session_native.php
+++ /dev/null
@@ -1,257 +0,0 @@
-<?php
-/**
- * CodeIgniter
- *
- * An open source application development framework for PHP
- *
- * This content is released under the MIT License (MIT)
- *
- * Copyright (c) 2014 - 2015, British Columbia Institute of Technology
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to deal
- * in the Software without restriction, including without limitation the rights
- * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
- * THE SOFTWARE.
- *
- * @package	CodeIgniter
- * @author	EllisLab Dev Team
- * @copyright	Copyright (c) 2008 - 2014, EllisLab, Inc. (http://ellislab.com/)
- * @copyright	Copyright (c) 2014 - 2015, British Columbia Institute of Technology (http://bcit.ca/)
- * @license	http://opensource.org/licenses/MIT	MIT License
- * @link	http://codeigniter.com
- * @since	Version 1.0.0
- * @filesource
- */
-defined('BASEPATH') OR exit('No direct script access allowed');
-
-/**
- * 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		EllisLab Dev Team
- */
-class CI_Session_native extends CI_Session_driver {
-
-	/**
-	 * Initialize session driver object
-	 *
-	 * @return	void
-	 */
-	protected function initialize()
-	{
-		// Get config parameters
-		$config = array();
-		$prefs = array(
-			'sess_cookie_name',
-			'sess_expire_on_close',
-			'sess_expiration',
-			'sess_match_ip',
-			'sess_match_useragent',
-			'sess_time_to_update',
-			'cookie_prefix',
-			'cookie_path',
-			'cookie_domain',
-			'cookie_secure',
-			'cookie_httponly'
-		);
-
-		foreach ($prefs as $key)
-		{
-			$config[$key] = isset($this->_parent->params[$key])
-				? $this->_parent->params[$key]
-				: $this->CI->config->item($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 = '';
-		$secure = (bool) $config['cookie_secure'];
-		$http_only = (bool) $config['cookie_httponly'];
-
-		if ($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, $secure, $http_only);
-
-		// Start session
-		session_start();
-
-		// Check session expiration, ip, and agent
-		$now = time();
-		$destroy = FALSE;
-		if (isset($_SESSION['last_activity']) && (($_SESSION['last_activity'] + $expire) < $now OR $_SESSION['last_activity'] > $now))
-		{
-			// Expired - destroy
-			log_message('debug', 'Session: Expired');
-			$destroy = TRUE;
-		}
-		elseif ($config['sess_match_ip'] === TRUE && isset($_SESSION['ip_address'])
-			&& $_SESSION['ip_address'] !== $this->CI->input->ip_address())
-		{
-			// IP doesn't match - destroy
-			log_message('debug', 'Session: IP address mismatch');
-			$destroy = TRUE;
-		}
-		elseif ($config['sess_match_useragent'] === TRUE && isset($_SESSION['user_agent'])
-			&& $_SESSION['user_agent'] !== trim(substr($this->CI->input->user_agent(), 0, 50)))
-		{
-			// Agent doesn't match - destroy
-			log_message('debug', 'Session: User Agent string mismatch');
-			$destroy = TRUE;
-		}
-
-		// Destroy expired or invalid session
-		if ($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)
-		{
-			// Changing the session ID amidst a series of AJAX calls causes problems
-			if ( ! $this->CI->input->is_ajax_request())
-			{
-				// Regenerate ID, but don't destroy session
-				log_message('debug', 'Session: Regenerate ID');
-				$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'] = $this->CI->input->ip_address();
-		}
-
-		if ($config['sess_match_useragent'] === TRUE && ! isset($_SESSION['user_agent']))
-		{
-			// Store user agent string
-			$_SESSION['user_agent'] = trim(substr($this->CI->input->user_agent(), 0, 50));
-		}
-
-		// Make session ID available
-		$_SESSION['session_id'] = session_id();
-	}
-
-	// ------------------------------------------------------------------------
-
-	/**
-	 * Save the session data
-	 *
-	 * @return	void
-	 */
-	public function sess_save()
-	{
-		// Nothing to do - changes to $_SESSION are automatically saved
-	}
-
-	// ------------------------------------------------------------------------
-
-	/**
-	 * Destroy the current session
-	 *
-	 * @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'], $params['secure'], $params['httponly']);
-			unset($_COOKIE[$name]);
-		}
-		session_destroy();
-	}
-
-	// ------------------------------------------------------------------------
-
-	/**
-	 * Regenerate the current session
-	 *
-	 * Regenerate the session id
-	 *
-	 * @param	bool	Destroy session data flag (default: FALSE)
-	 * @return	void
-	 */
-	public function sess_regenerate($destroy = FALSE)
-	{
-		// Just regenerate id, passing destroy flag
-		session_regenerate_id($destroy);
-		$_SESSION['session_id'] = session_id();
-	}
-
-	// ------------------------------------------------------------------------
-
-	/**
-	 * Get a reference to user data array
-	 *
-	 * @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 */
\ No newline at end of file
diff --git a/system/libraries/Session/drivers/Session_redis_driver.php b/system/libraries/Session/drivers/Session_redis_driver.php
new file mode 100644
index 000000000..c53975ae4
--- /dev/null
+++ b/system/libraries/Session/drivers/Session_redis_driver.php
@@ -0,0 +1,395 @@
+<?php
+/**
+ * CodeIgniter
+ *
+ * An open source application development framework for PHP
+ *
+ * This content is released under the MIT License (MIT)
+ *
+ * Copyright (c) 2014 - 2015, British Columbia Institute of Technology
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ *
+ * @package	CodeIgniter
+ * @author	EllisLab Dev Team
+ * @copyright	Copyright (c) 2008 - 2014, EllisLab, Inc. (http://ellislab.com/)
+ * @copyright	Copyright (c) 2014 - 2015, British Columbia Institute of Technology (http://bcit.ca/)
+ * @license	http://opensource.org/licenses/MIT	MIT License
+ * @link	http://codeigniter.com
+ * @since	Version 3.0.0
+ * @filesource
+ */
+defined('BASEPATH') OR exit('No direct script access allowed');
+
+/**
+ * CodeIgniter Session Redis Driver
+ *
+ * @package	CodeIgniter
+ * @subpackage	Libraries
+ * @category	Sessions
+ * @author	Andrey Andreev
+ * @link	http://codeigniter.com/user_guide/libraries/sessions.html
+ */
+class CI_Session_redis_driver extends CI_Session_driver implements SessionHandlerInterface {
+
+	/**
+	 * phpRedis instance
+	 *
+	 * @var	resource
+	 */
+	protected $_redis;
+
+	/**
+	 * Key prefix
+	 *
+	 * @var	string
+	 */
+	protected $_key_prefix = 'ci_session:';
+
+	/**
+	 * Lock key
+	 *
+	 * @var	string
+	 */
+	protected $_lock_key;
+
+	// ------------------------------------------------------------------------
+
+	/**
+	 * Class constructor
+	 *
+	 * @param	array	$params	Configuration parameters
+	 * @return	void
+	 */
+	public function __construct(&$params)
+	{
+		parent::__construct($params);
+
+		if (empty($this->_config['save_path']))
+		{
+			log_message('error', 'Session: No Redis save path configured.');
+		}
+		elseif (preg_match('#(?:tcp://)?([^:?]+)(?:\:(\d+))?(\?.+)?#', $this->_config['save_path'], $matches))
+		{
+			isset($matches[3]) OR $matches[3] = ''; // Just to avoid undefined index notices below
+			$this->_config['save_path'] = array(
+				'host' => $matches[1],
+				'port' => empty($matches[2]) ? NULL : $matches[2],
+				'password' => preg_match('#auth=([^\s&]+)#', $matches[3], $match) ? $match[1] : NULL,
+				'database' => preg_match('#database=(\d+)#', $matches[3], $match) ? (int) $match[1] : NULL,
+				'timeout' => preg_match('#timeout=(\d+\.\d+)#', $matches[3], $match) ? (float) $match[1] : NULL
+			);
+
+			preg_match('#prefix=([^\s&]+)#', $matches[3], $match) && $this->_key_prefix = $match[1];
+		}
+		else
+		{
+			log_message('error', 'Session: Invalid Redis save path format: '.$this->_config['save_path']);
+		}
+
+		if ($this->_config['match_ip'] === TRUE)
+		{
+			$this->_key_prefix .= $_SERVER['REMOTE_ADDR'].':';
+		}
+	}
+
+	// ------------------------------------------------------------------------
+
+	/**
+	 * Open
+	 *
+	 * Sanitizes save_path and initializes connection.
+	 *
+	 * @param	string	$save_path	Server path
+	 * @param	string	$name		Session cookie name, unused
+	 * @return	bool
+	 */
+	public function open($save_path, $name)
+	{
+		if (empty($this->_config['save_path']))
+		{
+			return FALSE;
+		}
+
+		$redis = new Redis();
+		if ( ! $redis->connect($this->_config['save_path']['host'], $this->_config['save_path']['port'], $this->_config['save_path']['timeout']))
+		{
+			log_message('error', 'Session: Unable to connect to Redis with the configured settings.');
+		}
+		elseif (isset($this->_config['save_path']['password']) && ! $redis->auth($this->_config['save_path']['password']))
+		{
+			log_message('error', 'Session: Unable to authenticate to Redis instance.');
+		}
+		elseif (isset($this->_config['save_path']['database']) && ! $redis->select($this->_config['save_path']['database']))
+		{
+			log_message('error', 'Session: Unable to select Redis database with index '.$this->_config['save_path']['database']);
+		}
+		else
+		{
+			$this->_redis = $redis;
+			return TRUE;
+		}
+
+		return FALSE;
+	}
+
+	// ------------------------------------------------------------------------
+
+	/**
+	 * Read
+	 *
+	 * Reads session data and acquires a lock
+	 *
+	 * @param	string	$session_id	Session ID
+	 * @return	string	Serialized session data
+	 */
+	public function read($session_id)
+	{
+		if (isset($this->_redis) && $this->_get_lock($session_id))
+		{
+			// Needed by write() to detect session_regenerate_id() calls
+			$this->_session_id = $session_id;
+
+			$session_data = (string) $this->_redis->get($this->_key_prefix.$session_id);
+			$this->_fingerprint = md5($session_data);
+			return $session_data;
+		}
+
+		return FALSE;
+	}
+
+	// ------------------------------------------------------------------------
+
+	/**
+	 * Write
+	 *
+	 * Writes (create / update) session data
+	 *
+	 * @param	string	$session_id	Session ID
+	 * @param	string	$session_data	Serialized session data
+	 * @return	bool
+	 */
+	public function write($session_id, $session_data)
+	{
+		if ( ! isset($this->_redis))
+		{
+			return FALSE;
+		}
+		// Was the ID regenerated?
+		elseif ($session_id !== $this->_session_id)
+		{
+			if ( ! $this->_release_lock() OR ! $this->_get_lock($session_id))
+			{
+				return FALSE;
+			}
+
+			$this->_fingerprint = md5('');
+			$this->_session_id = $session_id;
+		}
+
+		if (isset($this->_lock_key))
+		{
+			$this->_redis->setTimeout($this->_lock_key, 5);
+			if ($this->_fingerprint !== ($fingerprint = md5($session_data)))
+			{
+				if ($this->_redis->set($this->_key_prefix.$session_id, $session_data, $this->_config['expiration']))
+				{
+					$this->_fingerprint = $fingerprint;
+					return TRUE;
+				}
+
+				return FALSE;
+			}
+
+			return $this->_redis->setTimeout($this->_key_prefix.$session_id, $this->_config['expiration']);
+		}
+
+		return FALSE;
+	}
+
+	// ------------------------------------------------------------------------
+
+	/**
+	 * Close
+	 *
+	 * Releases locks and closes connection.
+	 *
+	 * @return	void
+	 */
+	public function close()
+	{
+		if (isset($this->_redis))
+		{
+			try {
+				if ($this->_redis->ping() === '+PONG')
+				{
+					isset($this->_lock_key) && $this->_redis->delete($this->_lock_key);
+					if ( ! $this->_redis->close())
+					{
+						return FALSE;
+					}
+				}
+			}
+			catch (RedisException $e)
+			{
+				log_message('error', 'Session: Got RedisException on close(): '.$e->getMessage());
+			}
+
+			$this->_redis = NULL;
+			return TRUE;
+		}
+
+		return TRUE;
+	}
+
+	// ------------------------------------------------------------------------
+
+	/**
+	 * Destroy
+	 *
+	 * Destroys the current session.
+	 *
+	 * @param	string	$session_id	Session ID
+	 * @return	bool
+	 */
+	public function destroy($session_id)
+	{
+		if (isset($this->_redis, $this->_lock_key))
+		{
+			if ($this->_redis->delete($this->_key_prefix.$session_id) !== 1)
+			{
+				log_message('debug', 'Session: Redis::delete() expected to return 1, got '.var_export($result, TRUE).' instead.');
+			}
+
+			return $this->_cookie_destroy();
+		}
+
+		return FALSE;
+	}
+
+	// ------------------------------------------------------------------------
+
+	/**
+	 * Garbage Collector
+	 *
+	 * Deletes expired sessions
+	 *
+	 * @param	int 	$maxlifetime	Maximum lifetime of sessions
+	 * @return	bool
+	 */
+	public function gc($maxlifetime)
+	{
+		// Not necessary, Redis takes care of that.
+		return TRUE;
+	}
+
+	// ------------------------------------------------------------------------
+
+	/**
+	 * Get lock
+	 *
+	 * Acquires an (emulated) lock.
+	 *
+	 * @param	string	$session_id	Session ID
+	 * @return	bool
+	 */
+	protected function _get_lock($session_id)
+	{
+		if (isset($this->_lock_key))
+		{
+			return $this->_redis->setTimeout($this->_lock_key, 5);
+		}
+
+		$lock_key = $this->_key_prefix.$session_id.':lock';
+		if (($ttl = $this->_redis->ttl($lock_key)) < 1)
+		{
+			if ( ! $this->_redis->setex($lock_key, 5, time()))
+			{
+				log_message('error', 'Session: Error while trying to obtain lock for '.$this->_key_prefix.$session_id);
+				return FALSE;
+			}
+
+			$this->_lock_key = $lock_key;
+
+			if ($ttl === -1)
+			{
+				log_message('debug', 'Session: Lock for '.$this->_key_prefix.$session_id.' had no TTL, overriding.');
+			}
+
+			$this->_lock = TRUE;
+			return TRUE;
+		}
+
+		// Another process has the lock, we'll try to wait for it to free itself ...
+		$attempt = 0;
+		while ($attempt++ < 5)
+		{
+			usleep(($ttl * 1000000) - 20000);
+			if (($ttl = $this->_redis->ttl($lock_key)) > 0)
+			{
+				continue;
+			}
+
+			if ( ! $this->_redis->setex($lock_key, 5, time()))
+			{
+				log_message('error', 'Session: Error while trying to obtain lock for '.$this->_key_prefix.$session_id);
+				return FALSE;
+			}
+
+			$this->_lock_key = $lock_key;
+			break;
+		}
+
+		if ($attempt === 5)
+		{
+			log_message('error', 'Session: Unable to obtain lock for '.$this->_key_prefix.$session_id.' after 5 attempts, aborting.');
+			return FALSE;
+		}
+
+		$this->_lock = TRUE;
+		return TRUE;
+	}
+
+	// ------------------------------------------------------------------------
+
+	/**
+	 * Release lock
+	 *
+	 * Releases a previously acquired lock
+	 *
+	 * @return	bool
+	 */
+	protected function _release_lock()
+	{
+		if (isset($this->_redis, $this->_lock_key) && $this->_lock)
+		{
+			if ( ! $this->_redis->delete($this->_lock_key))
+			{
+				log_message('error', 'Session: Error while trying to free lock for '.$this->_key_prefix.$session_id);
+				return FALSE;
+			}
+
+			$this->_lock_key = NULL;
+			$this->_lock = FALSE;
+		}
+
+		return TRUE;
+	}
+
+}