Re: Xrender and 64bit

Michael wrote:
> Hello,
> 
> I recently found out that whoever wrote Xrender apparently didn't waste
> a single thought on 64bit systems. Base types are unsigned longs ( see
> X11/extensions/render.h ):
> 
> typedef unsigned long	Glyph;
> typedef unsigned long	GlyphSet;
> typedef unsigned long	Picture;
> typedef unsigned long	PictFormat;
> 
> but everything seems to assume they're size 4 bytes and goes some
> lengths to ensure 4 byte alignment but this still leads to occasional
> SIGBUS from Xserver/render/render.c, especially
> ProcRenderCompositeGlyph(). A quick, working but dead ugly 'fix' is
> this: 
> 
> Index: render.c
> =================================================================== 
> RCS file: /cvsroot/xsrc/xfree/xc/programs/Xserver/render/render.c,v
> retrieving revision 1.1.1.6 diff -u -w -r1.1.1.6 render.c 
> --- render.c 18 Mar 2005 13:13:16 -0000      1.1.1.6 
> +++ render.c    24 Jul 2005 17:46:09 -0000 
> @@ -1300,7 +1300,7 @@
>         {
>             if (buffer + sizeof (GlyphSet) < end)
>             {
> -               gs = *(GlyphSet *) buffer;
> +               gs = *(CARD32 *) buffer;
>                 glyphSet = (GlyphSetPtr) SecurityLookupIDByType (client,
>                                                                  gs,
>                                                			 GlyphSetType, 
> 
> A real fix would be to change the base types to something that's always
> 32bit I think but that would disrupt more or less everything that uses
> Xrender since they're exposed to clients.
> 
> Any ideas what to do about this? On sparc64 this leads to firefox
> occasionally crashing the Xserver and I'm pretty sure it would affect
> other 64bit architectures as well.
> 
> have fun
> Michael

FYI, this is the same problem as: 
<https://bugs.freedesktop.org/attachment.cgi?id=3095>
-- 
Matthieu Herrb