Re: [Qemu-devel] [PATCH v2] linux-user: fix wait* syscall status returns

[Peter Maydell]

On 23 November 2011 23:44, Alexander Graf <address@hidden> wrote:
> When calling wait4 or waitpid with a status pointer and WNOHANG, the
> syscall can potentially not modify the status pointer input. Now if we
> have guest code like:
>
>  int status = 0;
>  waitpid(pid, &status, WNOHANG);
>  if (status)
>     <breakage>
>
> then we have to make sure that in case status did not change we actually
> return the guest's initialized status variable instead of our own 
> uninitialized.
> We fail to do so today, as we proxy everything through an uninitialized status
> variable which for me ended up always containing the last error code.
>
> This patch fixes some test cases when building yast2-core in OBS for ARM.
>
> Signed-off-by: Alexander Graf <address@hidden>

I'd have put both sets of checks on ret next to each other personally,
but that's hardly worth doing a v3 for.

Reviewed-by: Peter Maydell <address@hidden>

-- PMM