Re: pt_chown build failure

[Eric Blake]

On 10/19/2011 04:33 PM, Bruno Haible wrote:
> Hi Eric,
>
> > Also, I got a build failure when trying to use the grantpt module in
> > libvirt:
> >
> >     CCLD   libgnu.la
> >     CC     pt_chown.o
> > make[4]: *** No rule to make target `libgnu.a', needed by `pt_chown'.  Stop.
> >
> > Looks like the gnulib-tool output is not considering the possibility of
> > libtool mixing with the creation of pt_chown.
>
> I get the same build failure in testdirs that contain 'grantpt'.
>
> The easiest fix is probably to adjust modules/pt_chown locally for
> libvirt (via --local-dir and a modules/pt_chown.diff file).

See also my proposed patch, for an even easier fix that avoids the need 
for a diff file.

> Also
> you need to find a way to install the pt_chown program as setuid root.
> This too is outside the scope of gnulib.

Agreed there, and still a problem even with my proposed patches, 
although now the problem is limited to just platforms without grantpt, 
rather than all platforms.

> I'm not sure it's worth modifying gnulib-tool for this single case.

Well, my proposed patch still had one flaw - grantpt.c should _not_ be 
added into EXTRA_libgnu_la_SOURCES, since it is not part of the libgnu 
library but a standalone app; I'll send a v2 of my patch with a 
gnulib-tool tweak for this situation (gnulib-tool was already 
special-casing pt_chown when it existed as a separate module, so it's 
not too much of a stretch).

> > For that matter, does
> > pt_chown even need to be built on Linux, or can we rework things to only
> > build it on platforms where the grantpt() replacement is compiled?
>
> The dependency from 'grantpt' to 'pt_chown' has already the right
> condition attached. I think you only need to activate the
> --conditional-dependencies option. (But note that it does not yet
> work with --with-tests.)

Alas, libvirt wants to use --with-tests, so it cannot use 
--conditional-dependencies yet.  But I think my patch to consolidate 
things into one module, and use an automake conditional, solves that 
problem.

--
Eric Blake   address@hidden    +1-801-349-2682
Libvirt virtualization library http://libvirt.org