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

Jakub Hrozek jhrozek at redhat.com
Wed Jul 9 12:48:40 UTC 2014


On Wed, Jul 09, 2014 at 02:31:40PM +0200, Sumit Bose wrote:
> On Wed, Jul 09, 2014 at 01:15:17PM +0200, Jakub Hrozek wrote:
> > On Tue, Jul 08, 2014 at 11:04:27PM +0200, Lukas Slebodnik wrote:
> > > On (08/07/14 15:19), Sumit Bose wrote:
> > > >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.
> > > This change would only hide provides from rpm, which is not platform
> > > independent. I tried build libsss_nss_idmap.so in different way for
> > > test and for installation with custom make targets (check-local,
> > > install-exec-local, install-exec-hook). It was not possible because
> > > I would need targets which are executed before check or install and int the
> > > middle or after targets (check or install).
> > > 
> > > I decided to build library libsss_nss_idmap twice.
> > >     1) libsss_nss_idmap_test.so --will be used for sss_nss_idmap-test
> > >     2) libsss_nss_idmap.so --will be installed
> > > 
> > > Two version script files were combined for libsss_nss_idmap_test.so
> > > defualt sss_nss_idmap.exports and extra sss_nss_idmap.unit_tests, which
> > > contains function sss_nss_make_request.
> > > 
> > > LS
> > 
> > Originally I was going to say this breaks the purpose of unit tests that
> > we should stay as close to the production binaries as possible, but the
> > different is only in the version file (and rpath) and the
> > libsss_nss_idmap_la_* variables are used as a basis of the test library.
> > 
> > Provides also look sane,  nm output does, too.
> > 
> > I'm giving my ACK now, but I'll wait a bit before I push the patch in
> > case other developers didn't agree.
> 
> I agree, Lukas took care that the library used in the unit tests is as
> similar to the production one as possible by putting everything what is
> possible into variables. I think it is ok to proceed this way for the
> time being.

Thanks, pushed to master:
    f28b09f887870c10c8c611beee3c17eaa9ef74f3

> Nevertheless it might be a good idea to open a ticket for
> e.g. 1.13 as a reminder to try and find a solution. Maybe the binutils
> maintainers have something in their bag of tricks which might help here.

Can you open the ticket, Lukas?



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