    public static function mb_strstr($haystack, $needle, $part = false, $encoding = null)
    {
        $pos = strpos($haystack, $needle);
        if (false === $pos) {
            return false;
        }
        if ($part) {
            return substr($haystack, 0, $pos);
        }

        return substr($haystack, $pos);
    }
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.