[SSSD] [PATCH] BUILD: Add version symbol files for public libraries.

Sumit Bose sbose at redhat.com
Tue Jul 8 13:19:15 UTC 2014


On Tue, Jul 08, 2014 at 12:51:48PM +0200, Jakub Hrozek wrote:
> On Tue, Jul 08, 2014 at 11:21:09AM +0200, Lukas Slebodnik wrote:
> > On (08/07/14 09:27), Jakub Hrozek wrote:
> > >On Thu, Jun 26, 2014 at 10:31:27AM +0200, Lukas Slebodnik wrote:
> > >> ehlo,
> > >> 
> > >> attached patch fixes ticket #2194.
> > >> 
> > >> If you wan to know more about version script (version maps) here are links:
> > >> 
> > >> http://people.redhat.com/drepper/dsohowto.pdf
> > >>     (sections 2.2.5 .. 2.2.7, 3.4, 3.5)
> > >> https://www.gnu.org/software/gnulib/manual/html_node/LD-Version-Scripts.html
> > >> ftp://ftp.gnu.org/old-gnu/Manuals/ld-2.9.1/html_node/ld_25.html
> > >> 
> > >> LS
> > >
> > >I verified with:
> > >    nm -D $libname | awk '$2 == "T" {print $3";"}' | sort
> > >that the functions exported by the library match the functions defined
> > >in the version file.
> > >
> > >The versions also match the SONAMEs.
> > >
> > >One question inline:
> > >
> > >> From 0779624cf96480fe3b62f5c881fb9b123d24a965 Mon Sep 17 00:00:00 2001
> > >> From: Lukas Slebodnik <lslebodn at redhat.com>
> > >> Date: Mon, 9 Jun 2014 14:38:31 +0200
> > >> Subject: [PATCH] BUILD: Add version symbol files for public libraries.
> > >> 
> > >> Version symbol files will help package systems to catch backward compatible
> > >> changes (newly added functions) into library.
> > >> 
> > >> Resolves:
> > >> https://fedorahosted.org/sssd/ticket/2194
> > >
> > >[...]
> > >
> > >> new file mode 100644
> > >> index 0000000000000000000000000000000000000000..bd3abb211120784494fe366ddd19b94d9b982657
> > >> --- /dev/null
> > >> +++ b/src/sss_client/idmap/sss_nss_idmap.exports
> > >> @@ -0,0 +1,17 @@
> > >> +SSS_NSS_IDMAP_0.0.1 {
> > >> +
> > >> +    # public functions
> > >> +    global:
> > >> +
> > >> +        sss_nss_getsidbyname;
> > >> +        sss_nss_getsidbyid;
> > >> +        sss_nss_getnamebysid;
> > >> +        sss_nss_getidbysid;
> > >> +
> > >> +    # exported for mocking
> > >
> > >I don't think the comment is right. The symbol is exported because
> > >libsss_nss_idmap links with the client code:
> > >740 libsss_nss_idmap_la_SOURCES = \
> > >741     src/sss_client/idmap/sss_nss_idmap.c \
> > >742     src/sss_client/common.c \
> > >743     src/util/strtonum.c
> > >
> > >And libsss_nss_idmap uses the function to call out to the NSS responder
> > >(see src/sss_client/idmap/sss_nss_idmap.c:100)
> > >
> > >Can we not mark the function as global? It's not part of the sss_nss_idmap's
> > >API.
> > Try to comment out this symbol from file
> > --- a/src/sss_client/idmap/sss_nss_idmap.exports
> > +++ b/src/sss_client/idmap/sss_nss_idmap.exports
> > @@ -9,7 +9,7 @@ SSS_NSS_IDMAP_0.0.1 {
> >          sss_nss_getidbysid;
> >  
> >      # exported for mocking
> > -        sss_nss_make_request;
> > +    #    sss_nss_make_request;
> >  
> >      # everything else is local
> >      local:
> > 
> > sss_nss_idmap will fail, because function sss_nss_make_request cannot be mocked
> > sh-4.2$ cat sss_nss_idmap-tests.log
> > [==========] Running 1 test(s).
> > [ RUN      ] test_getsidbyname
> > 0x2 != 0
> > ../sssd/src/tests/cmocka/sss_nss_idmap-tests.c:102: error: Failure!
> > [  FAILED  ] test_getsidbyname
> > [==========] 1 test(s) run.
> > [  PASSED  ] 0 test(s).
> > [  FAILED  ] 1 test(s), listed below:
> > [  FAILED  ] test_getsidbyname
> > 
> > We can build libsss_nss_idmap twice.
> >     1) real library with version symbol file
> >     2) library without version symbol file only for tests (sss_nss_idmap-tests)
> > 
> > I was not able to find better solution.
> > 
> > LS
> 
> I tried playing a bit with Makefile.am and the only viable solution I
> see is to hardcode the list of libsss_nss_idmap sources in Makefile.am's
> sss_nss_idmap_tests_SOURCES except sss_client/common.c and mock
> sss_nss_lock and sss_nss_unlock..
> 
> But I'm not sure it's worth it, the rist is that a 3rd party links with
> sss_nss_make_request (which has no declaration in the public headers).
> 
> So now I prefer to push your original patch, but I would also like to
> hear other opinions, I'm not the biggest packaging expert around..

While discussing this on irc with Andreas (cmocka author) and Jakub we
came up with

SSS_NSS_IDMAP_0.0.1 {

    # public functions
    global:

        sss_nss_getsidbyname;
        sss_nss_getsidbyid;
        sss_nss_getnamebysid;
        sss_nss_getidbysid;

    # everything else is local
    local:
        *;
};

UNIT_TESTING_ONLY {
    global:
        sss_nss_make_request;
};

which would move the sss_nss_make_request into a separate version which
is not for public use. RPMs will still show a Provides like:

libsss_nss_idmap.so.0(UNIT_TESTING_ONLY)

which can be filtered out (at least on recent Fedora version) with

%global __provides_exclude ^.*FOR_CMOCKA.*$

in the spec file.

bye,
Sumit
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