[libvirt] libvirt-2.0.0 build error (hidden symbol libvirt_event_poll_update_handle_semaphore)

[Daniel P. Berrange]

On Tue, Jun 27, 2017 at 05:34:59PM +0800, longguang.yue wrote:
> Hi, all:
>     i back port a patch which makes qemu depends on util directory.
> so i correct its dependency  by applying a patch.  but another error occur.
> the patch is http://libvirt.org/git/?p=libvirt.git;a=commit;h=57b5e27d3d74f8dbb77ac909b405d99d555eca46

That's wrong - qemu (and every driver in libvirt) has *always* depended
on the util directory - nothing changed in that respect in this patch.
The patch adds a new method in the util code, and exports that method
to drivers in the normal manner.

> the patch fix dependency :
> --- libvirt-2.0.0/src/Makefile.am       2016-06-27 22:12:20.523191076 +0800
> +++ libvirt-2.0.0-ok/src/Makefile.am    2017-06-22 12:25:17.512000000 +0800
> @@ -1362,6 +1362,7 @@
>                 -I$(srcdir)/access \
>                 -I$(srcdir)/conf \
>                 -I$(srcdir)/secret \
> +               -I$(srcdir)/util \
>                 $(AM_CFLAGS)
>  libvirt_driver_qemu_impl_la_LDFLAGS = $(AM_LDFLAGS)
>  libvirt_driver_qemu_impl_la_LIBADD = $(CAPNG_LIBS) \
> @@ -1369,6 +1370,7 @@
>                                 $(LIBNL_LIBS) \
>                                 $(LIBXML_LIBS) \
>                                 libvirt_secret.la \
> +                               libvirt_util.la \
>                                 $(NULL)
>  libvirt_driver_qemu_impl_la_SOURCES = $(QEMU_DRIVER_SOURCES)

This is just wrong. Any symbols that QEMU uses from the libvirt_util.la
library are already linked into libvirtd and exported to the QEMU driver.
Linking QEMU to libvirt_util.la results in 2 copies the same code being
in-process which is broken.

>   CCLD     qemucapsprobe
> /bin/ld: .libs/qemucapsprobe: hidden symbol `libvirt_event_poll_update_handle_semaphore' in ../src/libvirt_probes.o is referenced by DSO
> /bin/ld: final link failed: Bad value
> collect2: error: ld returned 1 exit status

This looks unrelated to the patch you quote above. The patch doesn't
change qemucapsprobe, nor reference that hidden symbol. So I think
this is a pre-existing problem you have with your build and/or code
tree.


Regards,
Daniel
-- 
|: https://berrange.com      -o-    https://www.flickr.com/photos/dberrange :|
|: https://libvirt.org         -o-            https://fstop138.berrange.com :|
|: https://entangle-photo.org    -o-    https://www.instagram.com/dberrange :|