resovle CNAME to orig hostname

resovle_CNAME_to_orig_hostname.php

<?php
$hostname = $_SERVER['HTTP_HOST'];

$get_hostname_orig = function (&$hostname) use (&$get_hostname_orig) {
    $record = dns_get_record($hostname, DNS_CNAME);
    if (count($record) > 0) {
        $hostname = $record[0]['target'];
        $get_hostname_orig($hostname);
    }
};
$get_hostname_orig($hostname);

echo $hostname;