[LTP] [RFC] [PATCH] lib32: Add support for linking 32bit programs on 64bit

[Cyril Hrubis]

Hi!
> > * The directory lib32 contains symlinks of minimal set of sources
> >   needed to link newlib testcase + Makefile.
> 
> Apparently missing safe_socket which is required for cve-2016-4997.c, but that
> is easy to fix I suppose.

That is just one symlink away...

> > * The testcases.mk builds 32bit library as well if
> >   32bit compiler was installed (-m32 configure test was succesful)
> > 
> > * And finally the env_post.mk switches between lib and lib32 depeding
> >   on if -m32 was passed in the CFLAGS
> 
> I added "cve-2016-4997: CFLAGS += -m32" and it still tried to look in
> "../../lib"

Hmm, that is not easy to fix, since this is target specific variable and
we simply do not see the -m32 in the CFLAGS in the condition below.

We would have to set the LDFLAGS per target and I'm not sure if we can
easily do that.

> > +ifeq ($(filter -m32,$(CFLAGS)),)
> >  LDFLAGS				+= -L$(top_builddir)/lib
> > +else
> > +LDFLAGS				+= -L$(top_builddir)/lib32
> > +endif
> 
> I was able to remove the if statement (i.e. put both dirs on the search path)
> and the 64-bit tests still compiled fine and so did the 32-bit test, although
> maybe not all linkers can be trusted to ignore libs with the wrong number of
> bits.

While this works mostly fine it produces warnings I would like to avoid.

-- 
Cyril Hrubis
chrubis@suse.cz