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<?php
DEFINE("SESSION_FILE_PREFIX" ,"session_test_");
/*
* == General Return Value Rule ==
*
* Returning FALSE indicates FATAL error.
* Exceptions are: gc(), validate_sid()
*
* == Session Data Lock ==
*
* Session data lock is mandatory. Lock must be exclusive. i.e. Block read also.
*
* == Collision Detection ==
*
* Collision detection is mandatory to reject attacker initialized session ID.
* Coolision detection is absolute requirement for secure session.
*/
/* Open session data database */
function open($save_path, $session_name) {
// string $save_path - Directory path, connection strings, etc. Default: session.save_path
// string $session_name - Session ID cookie name. Default: session.name
global $session_save_path, $name;
$session_save_path = $save_path;
$name = $session_name;
echo "Open [${session_save_path},${session_name}]\n";
// MUST return bool. Return TRUE for success.
return true;
}
/* Close session data database */
function close() {
// void parameter
// NOTE: This function should unlock session data, if write() does not unlock it.
global $session_save_path, $name;
echo "Close [${session_save_path},${name}]\n";
// MUST return bool. Return TRUE for success.
return true;
}
/* Read session data */
function read($id) {
// string $id - Session ID string
// NOTE: All production session save handler MUST implement "exclusive" lock.
// e.g. Use "serializable transaction isolation level" with RDBMS.
// read() would be the best place for locking for most save handlers.
global $session_save_path, $name, $session_id;
$session_id = $id;
echo "Read [${session_save_path},${id}]\n";
$session_file = "$session_save_path/".SESSION_FILE_PREFIX.$id;
// read MUST create file. Otherwise, strict mode will not work
touch($session_file);
// MUST return STRING for successful read().
// Return FALSE only when there is error. i.e. Do not return FALSE
// for non-existing session data for the $id.
return (string) @file_get_contents($session_file);
}
/* Write session data */
function write($id, $session_data) {
// string $id - Session ID string
// string $session_data - Session data string serialized by session serializer.
// NOTE: This function may unlock session data locked by read(). If write() is
// is not suitable place your handler to unlock. Unlock data at close().
global $session_save_path, $name, $session_id;
$session_id = $id;
echo "Write [${session_save_path},${id},${session_data}]\n";
$session_file = "$session_save_path/".SESSION_FILE_PREFIX.$id;
if ($fp = fopen($session_file, "w")) {
$return = fwrite($fp, $session_data);
fclose($fp);
return $return === FALSE ? FALSE : TRUE;
}
// MUST return bool. Return TRUE for success.
return false;
}
/* Remove specified session */
function destroy($id) {
// string $id - Session ID string
global $session_save_path, $name;
echo "Destroy [${session_save_path},${id}]\n";
$session_file = "$session_save_path/".SESSION_FILE_PREFIX.$id;
unlink($session_file);
// MUST return bool. Return TRUE for success.
// Return FALSE only when there is error. i.e. Do not return FALSE
// for non-existing session data for the $id.
return true;
}
/* Perform garbage collection */
function gc($maxlifetime) {
// long $maxlifetime - GC TTL in seconds. Default: session.gc_maxlifetime
global $session_save_path, $name;
$gc_cnt = 0;
$directory = opendir($session_save_path."/");
$length = strlen(SESSION_FILE_PREFIX);
while (($file = readdir($directory)) !== FALSE) {
$qualified = ($session_save_path."/".$file);
if (is_file($qualified) === TRUE) {
if (substr($file, 0, $length) === SESSION_FILE_PREFIX && (filemtime($qualified) + $maxlifetime <= time() )) {
unlink($qualified);
$gc_cnt++;
}
}
}
closedir($directory);
// SHOULD return long (number of deleted sessions).
// Returning TRUE works also, but it will not report correct number of deleted sessions.
// Return negative value for error. FALSE does not work because it's the same as 0.
return $gc_cnt;
}
/* Create new secure session ID */
function create_sid() {
// void parameter
// NOTE: Defining create_sid() is mandatory because validate_sid() is mandatory for
// security reasons for production save handler.
// PHP 7.1 has session_create_id() for secure session ID generation. Older PHPs
// must generate secure session ID by yourself.
// e.g. hash('sha2', random_bytes(64)) or use /dev/urandom
$id = ('PHPT-'.time());
echo "CreateID [${id}]\n";
// MUST return session ID string.
// Return FALSE for error.
return $id;
}
/* Check session ID collision */
function validate_sid($id) {
// string $id - Session ID string
global $session_save_path, $name;
echo "ValidateID [${session_save_path},${id}]\n";
$session_file = "$session_save_path/".SESSION_FILE_PREFIX.$id;
$ret = file_exists($session_file);
// MUST return bool. Return TRUE for collision.
// NOTE: This handler is mandatory for session security.
// All save handlers MUST implement this handler.
// Check session ID collision, return TRUE when it collides.
// Otherwise, return FALSE.
return $ret;
}
/* Update session data access time stamp WITHOUT writing $session_data */
function update($id, $session_data) {
// string $id - Session ID string
// string $session_data - Session data serialized by session serializer
// NOTE: This handler is optional. If your session database cannot
// support time stamp updating, you must not define this.
global $session_save_path, $name;
echo "Update [${session_save_path},${id}]\n";
$session_file = "$session_save_path/".SESSION_FILE_PREFIX.$id;
$ret = touch($session_file);
// MUST return bool. Return TRUE for success.
return $ret;
}
function feature() {
/* NOT IMPLEMENTED YET */
/* TYPES: gc, create_sid, use_strict_mode, minimzie_lock, lazy_write
/* VALUES: 0=unknown, 1=supported, 2=partially supported, 3=unsupported */
return array('gc'=>0,
'create_sid'=>1,
'use_strict_mode'=>2,
'minimize_lock'=>3,
'lazy_write'=>4,
'invalid'=>5,
'another invalid'=>6
);
}
?>
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