Description:
------------
When renaming a file (via the "rename" function) across filesystems, owner, group and permission information will be lost if (a) we are running as root and (b) the file is not owned by root.

Additionally, I suspect that permission information can be lost even if (a) we are not running as root and (b) we are running as the user who owns the file.


Reproduce code:
---------------
<?php

// I am running as root
touch ("/tmp/testfile");
passthru ("ls -l /tmp/testfile");

chown ("/tmp/testfile", "nobody");
chgrp ("/tmp/testfile", "nobody");
chmod ("/tmp/testfile", 0);
passthru ("ls -l /tmp/testfile");

rename ("/tmp/testfile", "/tmp/testfile2");
passthru ("ls -l /tmp/testfile2");

rename ("/tmp/testfile2", "/home/testfile2");
passthru ("ls -l /home/testfile2");

?>


Expected result:
----------------
-rw-r--r--  1 root  wheel  0 Oct 10 18:53 /tmp/testfile
----------  1 nobody  nobody  0 Oct 10 18:53 /tmp/testfile
----------  1 nobody  nobody  0 Oct 10 18:53 /tmp/testfile2
----------  1 nobody  nobody  0 Oct 10 18:53 /home/testfile2


Actual result:
--------------
-rw-r--r--  1 root  wheel  0 Oct 10 18:53 /tmp/testfile
----------  1 nobody  nobody  0 Oct 10 18:53 /tmp/testfile
----------  1 nobody  nobody  0 Oct 10 18:53 /tmp/testfile2
-rw-r--r--  1 root  wheel  0 Oct 10 18:53 /home/testfile2