// Functions
function _loginUser($username, $password){
    $pass = md5($password);
    $query = sprintf("SELECT dc_user, dc_pass FROM dc_cms WHERE dc_user='%s' LIMIT 1", mysql_real_escape_string($username));
    $result = mysql_query($query) or die(mysql_error());
    if (mysql_num_rows($result) > 0){
        $row = mysql_fetch_array($result);
        if ($pass == $row['dc_pass']) {
            return true;
        } else return false;
    } else return false;
}
function _regsession($user, $pass){
    $_SESSION['user'] = $user;
    $_SESSION['pass'] = $pass;
}
// Control of login
if ($_REQUEST['s'] == "login") {
    if (isset($_POST['s_user']) && $_POST['s_pass']) {
        if (_loginUser($_POST['s_user'], $_POST['s_pass']) == true) {
            _regsession($_POST['s_user'], $_POST['s_pass']);
        }
    }
}