    public static function exist($mod)
    {
        $file = GX_MOD.'/'.$mod.'/options.php';
        if (file_exists($file)) {
            return true;
        } else {
            return false;
        }
    }
The software constructs all or part of an SQL command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended SQL command when it is sent to a downstream component.