On Fri, Jun 01, 2012 at 05:00:58PM +0200, Florian Weimer wrote:
> On 06/01/2012 03:34 PM, Jakub Jelinek wrote:
> >The standard -D_FORTIFY_SOURCE failure is __chk_fail (), so IMNSHO
> >if this is presented as _FORTIFY_SOURCE check, it should call that
> >and not some other function. You'd need to use
> >#if __USE_FORTIFY_LEVEL> 0
> >test instead (as __chk_fail is only provided by glibcs that on
> >_FORTIFY_SOURCE definition sets __USE_FORTIFY_LEVEL), but it would be
> >consistent with all other fortification failures (and, even
> >-fstack-protector failures are similar).
>
> __chk_fail it is, then. This means that the test case will be
> specific to GNU libc platforms. How can I mark it as such?
{ target *-*-linux* } or so?
> >Or of course if you want it to do something else on failures, better
> >enable it using a different macro.
>
> I'm aiming for a consistent developer experience.
For other platforms there is always libssp included with gcc, which can be
used instead (users then have to link -lssp if they compile with
-D_FORTIFY_SOURCE).
Note, __chk_fail () isn't prototyped in glibc headers, so you want
probably in the checking method declare it in some __gnu* namespace
as extern "C" __chk_fail () __attribute__((unused));
and then use.
Jakub
