PHP Decode

<?php 
 
ini_set('display_errors', 1); 
error_reporting(E_ALL); 
 
$flag = shell_exec("/readflag"); 
 
if(isset($_GET['action']) && isset($_GET['p'])) { 
    $action = $_REQUEST['action']; 
    $p = $_REQUEST['p']; 
 
    if($p == 'flag') { 
        die("p contains an illegal value"); 
    } 
     
    if($_GET['action'] == 'flag') { 
        die("action contains an illegal value"); 
    } 
     
    if($_SERVER['CONTENT_TYPE'] != 'application/x-www-form-urlencoded' && strpos($_SERVER['CONTENT_TYPE'], "multipart") !== 0) { 
        if($_REQUEST['token'] == 0 && md5($_REQUEST['token']) == 0) { 
            echo compact($action)[trim($p)]; 
        } 
        else { 
            echo "Almost there"; 
        } 
    } 
} 
 
?>