session.php 9.64 KB
Newer Older
1
2
3
4
<?php
/**
 *
 * @package    mahara
Nigel McNie's avatar
Nigel McNie committed
5
 * @subpackage core
6
 * @author     Catalyst IT Ltd
7
8
 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL version 3 or later
 * @copyright  For copyright information on Mahara, please see the README file distributed with this software.
9
10
11
12
13
 *
 */

defined('INTERNAL') || die();

14
15
16
//
// Set session settings
//
17
session_name(get_config('cookieprefix') . 'mahara');
18
19
ini_set('session.save_path', '3;' . get_config('dataroot') . 'sessions');
ini_set('session.gc_divisor', 1000);
20
ini_set('session.gc_maxlifetime', get_config('session_timeout'));
21
ini_set('session.use_only_cookies', true);
22
23
24
if ($domain = get_config('cookiedomain')) {
    ini_set('session.cookie_domain', $domain);
}
25
26
ini_set('session.cookie_path', get_mahara_install_subdirectory());
ini_set('session.cookie_httponly', 1);
27
ini_set('session.hash_bits_per_character', 4);
28
ini_set('session.hash_function', 0);
29
30
31
if (is_https()) {
    ini_set('session.cookie_secure', true);
}
32

33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
// Attempt to create session directories
$sessionpath = get_config('dataroot') . 'sessions';
if (!is_dir("$sessionpath/0")) {
    // Create three levels of directories, named 0-9, a-f
    $characters = array('0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f');
    foreach ($characters as $c1) {
        check_dir_exists("$sessionpath/$c1");
        foreach ($characters as $c2) {
            check_dir_exists("$sessionpath/$c1/$c2");
            foreach ($characters as $c3) {
                check_dir_exists("$sessionpath/$c1/$c2/$c3");
            }
        }
    }
}

49
/**
50
 * The session class handles session data and messages.
51
 *
52
53
54
55
 * This class stores information across page loads, using only a cookie to
 * remember the info. User information is stored in the session so it does
 * not have to be requested each time the page is loaded, however any other
 * information can also be stored using this class.
56
57
58
59
 *
 * This class also is smart about giving out sessions - if a visitor
 * has not logged in (e.g. they are a guest, searchbot or a simple
 * 'curl' request), a session will not be created for them.
60
 *
61
62
 * Messages are stored in the session and are displayed the next time
 * a page is displayed to a user, even over multiple requests.
63
64
65
 */
class Session {

66
    /**
67
     * Resumes an existing session, only if there is one
68
     */
69
    private function __construct() {
70
        // Resume an existing session if required
71
        if (isset($_COOKIE[session_name()])) {
72
            @session_start();
73
74
75
        }
    }

76
77
78
79
80
81
82
83
84
85
86
87
    /**
     * Singelton function keeps us from generating multiple instances of this
     * class
     *
     * @return object   The class instance
     * @access public
     */
    public static function singleton() {
        //single instance
        static $instance;

        //if we don't have the single instance, create one
88
        if (!isset($instance)) {
89
90
91
92
93
            $instance = new Session();
        }
        return($instance);
    }

94
95
96
97
98
99
100
101
102
103
    /**
     * Gets the session property keyed by $key.
     *
     * @param string $key The key to get the value of
     * @return mixed
     */
    public function get($key) {
        if (isset($_SESSION[$key])) {
            return $_SESSION[$key];
        }
Penny Leach's avatar
Penny Leach committed
104
105
106
        return null;
    }

107
108
109
110
111
112
113
    /**
     * Sets the session property keyed by $key.
     *
     * @param string $key   The key to set.
     * @param string $value The value to set for the key
     */
    public function set($key, $value) {
114
        $this->ensure_session();
115
        $_SESSION[$key] = $value;
116
117
    }

Martyn Smith's avatar
Martyn Smith committed
118
119
120
121
122
    /**
     * Clears the session property keyed by $key (by setting it to null).
     *
     * @param string $key   The key to set.
     */
Martyn Smith's avatar
Martyn Smith committed
123
    public function clear($key) {
Martyn Smith's avatar
Martyn Smith committed
124
125
126
127
        $this->ensure_session();
        $_SESSION[$key] = null;
    }

128
129
130
131
132
133
134
    /**
     * Adds a message that indicates something was successful
     *
     * @param string $message The message to add
     * @param boolean $escape Whether to HTML escape the message
     */
    public function add_ok_msg($message, $escape=true) {
135
        $this->ensure_session();
136
        if ($escape) {
137
            $message = self::escape_message($message);
138
139
140
141
142
143
144
145
146
147
148
        }
        $_SESSION['messages'][] = array('type' => 'ok', 'msg' => $message);
    }

    /**
     * Adds a message that indicates an informational message
     *
     * @param string $message The message to add
     * @param boolean $escape Whether to HTML escape the message
     */
    public function add_info_msg($message, $escape=true) {
149
        $this->ensure_session();
150
        if ($escape) {
151
            $message = self::escape_message($message);
152
153
154
155
156
157
158
159
160
161
        }
        $_SESSION['messages'][] = array('type' => 'info', 'msg' => $message);
    }

    /**
     * Adds a message that indicates a failure to do something
     *
     * @param string $message The message to add
     * @param boolean $escape Whether to HTML escape the message
     */
162
    public function add_error_msg($message, $escape=true) {
163
        $this->ensure_session();
164
        if ($escape) {
165
            $message = self::escape_message($message);
166
        }
167
        $_SESSION['messages'][] = array('type' => 'error', 'msg' => $message);
168
169
170
171
172
173
174
175
176
177
178
179
180
    }

    /**
     * Builds HTML that represents all of the messages and returns it.
     *
     * This is designed to let smarty templates hook in any session messages.
     *
     * Calling this function will destroy the session messages that were
     * rendered, so they do not inadvertently get displayed again.
     *
     * @return string The HTML representing all of the session messages.
     */
    public function render_messages() {
181
        global $THEME;
182
        $result = '<div id="messages">';
183
184
        if (isset($_SESSION['messages'])) {
            foreach ($_SESSION['messages'] as $data) {
185
186
                $result .= '<div class="' . $data['type'] . '"><div>';
                $result .= $data['msg'] . '</div></div>';
187
            }
188
            $_SESSION['messages'] = array();
189
        }
190
        $result .= '</div>';
191
192
193
        return $result;
    }

194
    /**
195
     * Create a session, by initialising the $_SESSION array.
196
     */
197
198
199
    private function ensure_session() {
        if (empty($_SESSION)) {
            if (!session_id()) {
200
                @session_start();
201
202
203
204
            }
            $_SESSION = array(
                'messages' => array()
            );
205
        }
206
207
    }

208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
    /**
     * Destroy a session
     */
    public function destroy_session() {
        if ($this->is_live()) {
            $_SESSION = array();
            if (isset($_COOKIE[session_name()])) {
                setcookie(session_name(), '', time() - 65536,
                    ini_get('session.cookie_path'),
                    ini_get('session.cookie_domain'),
                    ini_get('session.cookie_secure'),
                    ini_get('session.cookie_httponly')
                );
            }
            session_destroy();
        }
    }

226
227
228
229
230
231
232
233
234
235
    /**
     * Find out if the session has been started yet
     */
    public function is_live() {
        if ("" == session_id()) {
            return false;
        }
        return true;
    }

236
237
    /**
     * Escape a message for HTML output
238
     *
239
240
241
242
243
244
245
     * @param string $message The message to escape
     * @return string         The message, escaped for output as HTML
     */
    private static function escape_message($message) {
        $message = hsc($message);
        $message = str_replace('  ', '&nbsp; ', $message);
        return $message;
246
    }
247

248
249
250
251
252
253
254
255
256
257
258
259
}

/**
 * A smarty callback to insert page messages
 *
 * @return string The HTML represening all of the session messages.
 */
function insert_messages() {
    global $SESSION;
    return $SESSION->render_messages();
}

260

261
262
263
264
/**
 * Delete all sessions belonging to a given user except for the current one
 */
function remove_user_sessions($userid) {
265
    global $sessionpath, $USER, $SESSION;
266

267
    $sessionids = get_column('usr_session', 'session', 'usr', (int) $userid);
268
269

    if (empty($sessionids)) {
270
271
272
273
274
        return;
    }

    $alive = array();
    $dead = array();
275
276
277
278
279
280
281
282
283
284

    // Keep track of the current session id so we can return to it at the end
    if ($SESSION->is_live()) {
        $sid = $USER->get('sessionid');
    }
    else {
        // The user has no session (this function is being called by a CLI script)
        $sid = false;
    }

285
    foreach ($sessionids as $sessionid) {
286
287
288
        if ($sessionid == $sid) {
            continue;
        }
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
        $file = $sessionpath;
        for ($i = 0; $i < 3; $i++) {
            $file .= '/' . substr($sessionid, $i, 1);
        }
        $file .= '/sess_' . $sessionid;
        if (file_exists($file)) {
            $alive[] = $sessionid;
        }
        else {
            $dead[] = $sessionid;
        }
    }

    if (!empty($dead)) {
        delete_records_select('usr_session', 'session IN (' . join(',', array_map('db_quote', $dead)) . ')');
    }

    if (empty($alive)) {
        return;
    }

    session_commit();

    foreach ($alive as $sessionid) {
        session_id($sessionid);
        if (session_start()) {
            session_destroy();
            session_commit();
        }
    }

320
321
322
323
    if ($sid !== false) {
        session_id($sid);
        session_start();
    }
324
325
326
327

    delete_records_select('usr_session', 'session IN (' . join(',', array_map('db_quote', $alive)) . ')');
}

328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
/**
 * Delete all session files except for the current one
 */
function remove_all_sessions() {
    global $sessionpath, $USER;

    $sid = $USER->get('sessionid');

    $iterator = new RecursiveIteratorIterator(new RecursiveDirectoryIterator($sessionpath));
    foreach ($iterator as $path) {
        if ($path->isFile() && $path->getFilename() !== ('sess_' . $sid)) {
            @unlink($path->getPathname());
        }
    }
    clearstatcache();

    delete_records_select('usr_session', 'session != ?', array($sid));
}