Re: mig hack (was: Re: nss is broken

[Marcus Brinkmann]

On Tue, Jul 30, 2002 at 07:40:06PM -0700, Thomas Bushnell, BSG wrote:
> > 2002-07-31  Marcus Brinkmann  <marcus@gnu.org>
> > 
> >         * routine.c (rtFindSize): Always add sizeof_mach_msg_type_t to
> >         SIZE for args not in long form, irregardless of the itSize.
> 
> I fear that this fixes that case, but runs the risk of breaking the
> case of passing shorts and chars when alignment might matter.

sizeof_mach_msg_type_t is 4 on x86 (and probably at least four on every
other machine we ever will care about).  itSize/8 will only be added if it
is larger than this value 4, that means that it does always add at least 4.

If you have a short or a byte, 4 will be added anyway.  Alignment is done by
padding, if I understood it correctly, and padding is added elsewhere in
type.c:

static void
itCalculateSizeInfo(register ipc_type_t *it)
{
    if (it->itInLine)
    {
        u_int bytes = (it->itNumber * it->itSize + 7) / 8;
        u_int padding = (4 - bytes%4)%4;

        it->itTypeSize = bytes;
        it->itPadSize = padding;

...

Am I confused?

Thanks,
Marcus

-- 
`Rhubarb is no Egyptian god.' GNU      http://www.gnu.org    marcus@gnu.org
Marcus Brinkmann              The Hurd http://www.gnu.org/software/hurd/
Marcus.Brinkmann@ruhr-uni-bochum.de
http://www.marcus-brinkmann.de/