[PATCH] Just another round of random cleanups

[Martin Schwenke]

On Thu, 18 Sep 2014 17:21:07 +1000, Martin Schwenke <martin at meltin.net>
wrote:

> On Thu, 18 Sep 2014 07:04:33 +0200, Volker Lendecke
> <Volker.Lendecke at SerNet.DE> wrote:
> 
> > On Thu, Sep 18, 2014 at 01:58:34PM +1000, Martin Schwenke wrote:
> > > On Thu, 18 Sep 2014 13:51:18 +1000, Martin Schwenke <martin at meltin.net>
> > > wrote:
> > > 
> > > > I think that when a library depends on a subsystem, then the library
> > > > ends up including the objects for that subsystem.  So, I suppose
> > > > that tdb-wrap, samba-util and errors all contain samba-debug.
> > > 
> > >   martins at rover:~/samba/samba (merge)$ nm bin/default/lib/util/libsamba-util.so  | grep check_log_size
> > >   000105f4 T check_log_size
> > >   0001056b T force_check_log_size
> > >   0001059c T need_to_check_log_size
> > >   martins at rover:~/samba/samba (merge)$ nm bin/default/lib/tdb_wrap/libtdb-wrap.so  | grep check_log_size
> > >   00002836 T check_log_size
> > >   000027ad T force_check_log_size
> > >   000027de T need_to_check_log_size
> > >   martins at rover:~/samba/samba (merge)$ nm bin/default/libcli/util/liberrors.so  | grep check_log_size
> > >   00019afa T check_log_size
> > >   00019a71 T force_check_log_size
> > >   00019aa2 T need_to_check_log_size
> > > 
> > > There it is!  So, either there is a way around this or it isn't a
> > > problem...  ;-)
> > 
> > They way around it might be making samba-debug a library.
> > But that sounds weird to me.
> 
> Yeah, I think we're going to have to do that.  Hopefully if samba-util
> is a public library and samba-debug is a private library, then the
> correct waf-fu will happen so that users like OpenChange won't have any
> issues.  However, Alexander said this one IRC:
> 
>   <schwenke> ab: if one of the libraries is a public library then the
>              dep library needs to be public too?
> 
>   <ab> schwenke: not really, at least from technical perspective --
>              you can have rpath hardcoded to point to private
>              library. I'm not sure whether waf handles that though
> 
> I guess we can try it...

OK, if you configure like this:

  ./configure  --enable-developer --dup-symbol-check
  
and build, then

  make test

looks like it does the symbol checking.  I wish I could figure out how
it does that and whether there is a more direct way of invoking the
check.  Sadly, I can't seem to figure out how "make test" works...  :-(

If I make samba-debug a private library then we hit the next hurdle:

  [4071/4194] symbol duplicate checking: 
  Waf: Leaving directory `/home/martins/samba/samba/bin'
  Build failed: default/source3/lib/netapi/examples/localgroup/localgroup_setinfo: Symbol set_blocking linked in multiple libraries ['samba-util', 'smb_transport']

So, it looks like we need to create a new (private) library every time
we try to break something out so that it can be used as a fine-grained
dependency for more than one thing.

We probably need to check if all the right linker magic happens so that
binaries linked to the public samba-util can find the private libraries
too.  It looks like at least some of that magic is there:

  $ ldd bin/default/lib/util/libsamba-util.so 
	linux-gate.so.1 (0xf77c8000)
	libpthread.so.0 => /lib/i386-linux-gnu/i686/cmov/libpthread.so.0 (0xf7756000)
	libsamba-debug.so => /home/martins/samba/samba/bin/shared/private/libsamba-debug.so (0xf7750000)

I'm happy to do convert subsystems into private libraries... but I'd
like to hear opinions from people with a better understanding of the
build system before I start down this road.

peace & happiness,
martin