commit ee1045877a7e226945c7cec2bda80039bd2d0c8e
author Jonathan Neuschäfer <j.neuschaefer@gmx.net> Thu Sep 03 07:27:26 2015 +0200
committer Riku Voipio <riku.voipio@linaro.org> Mon Sep 28 16:39:43 2015 +0300
tree 00161e36d739a5ccfb44e26d25f1708bb1ddc9ab
parent 59baae9a626396a3a05840279084c4bf2beb8f40

linux-user: fix cmsg conversion in case of multiple headers

Currently, __target_cmsg_nxthdr compares a pointer derived from
target_cmsg against the msg_control field of target_msgh (through
subtraction).  This failed for me when emulating i386 code under x86_64,
because pointers in the host address space and pointers in the guest
address space were not the same.  This patch passes the initial value of
target_cmsg into __target_cmsg_nxthdr.

I found and fixed two more related bugs:
- __target_cmsg_nxthdr now returns the new cmsg pointer instead of the
  old one.
- tgt_space (in host_to_target_cmsg) doesn't count "sizeof (struct
  target_cmsghdr)" twice anymore.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net>
Signed-off-by: Riku Voipio <riku.voipio@linaro.org>