Re: [libvirt] namespace clean shared libraries

[Daniel P. Berrange]

On Thu, Aug 02, 2012 at 03:14:27PM +0200, Wido den Hollander wrote:
> On 08/02/2012 01:37 PM, Daniel P. Berrange wrote:
> >On Thu, Aug 02, 2012 at 01:18:12PM +0200, Wido den Hollander wrote:
> >>On 07/08/2012 07:51 PM, Bruno Haible wrote:
> >>>Daniel P. Berrange wrote:
> >>>>If its better to just do it in libvirt config.h, then we
> >>>>can do that too
> >>>
> >>>Yes, doing '#define foo libvirt_foo' in config.h is the preferred way
> >>>of achieving a namespace clean shared library.
> >>>
> >>>There are two ways to generate these #defines:
> >>>
> >>>1) You collect manually, on various systems, the set of symbols that you
> >>>    don't want to clash with symbols from other shared libraries. You need
> >>>    to do this on various systems, because gnulib may define functions
> >>>    'rpl_fflush' or 'dprintf' on some systems and not on others.
> >>>
> >>>2) You collect, from a set of header files, the set of symbols that you
> >>>    want to have exported, and process all other symbols with
> >>>      '#define foo libvirt_foo'
> >>>
> >>>    This approach is more robust, but requires to compile all *.o files
> >>>    twice: Once with the initial settings (no #define), and once for real.
> >>>
> >>>    This approach is implemented in libunistring. Look at the config.h rule
> >>>    in this Makefile.am [1]. There are two auxiliary scripts: 
> >>> 'declared.sh' [2]
> >>>    extracts the symbols from a .h file (assuming a particular coding 
> >>> style).
> >>>    'exported.sh' [3] extracts te symbols of a .o file.
> >>>
> >>
> >>I don't want to rush anything, but I see that libvirt 0.10 will be
> >>coming out soon and I don't think this has been corrected?
> >>
> >>Right now this means that libvirt is not usable on Ubuntu 12.04
> >>systems when you want to use the secrets of libvirt.
> >>
> >>Is it feasible to have this fixed before 0.10 comes out?
> >
> >Try applying this patch to your source tree
> >
> >diff --git a/configure.ac b/configure.ac
> >index 6b189db..4f906bb 100644
> >--- a/configure.ac
> >+++ b/configure.ac
> >@@ -2876,6 +2876,10 @@ test "x$lv_cv_static_analysis" = xyes && t=1
> >  AC_DEFINE_UNQUOTED([STATIC_ANALYSIS], [$t],
> >    [Define to 1 when performing static analysis.])
> >
> >+AC_DEFINE_UNQUOTED([isbase64],[gnulib_isbase64],[Hack to avoid symbol 
> >clash])
> >+AC_DEFINE_UNQUOTED([base64_encode],[gnulib_base64_encode],[Hack to avoid 
> >symbol clash])
> >+AC_DEFINE_UNQUOTED([base64_encode_alloc],[gnulib_base64_encode_alloc],[Hack 
> >to avoid symbol clash])
> >+
> >  AC_OUTPUT(Makefile src/Makefile include/Makefile docs/Makefile \
> >           docs/schemas/Makefile \
> >           gnulib/lib/Makefile \
> 
> Yes, that works for me. The secrets are working on Ubuntu 12.04.

Ok, I'll apply this, but with a 'libvirt_' prefix as Bruno requested

Daniel
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