[libvirt] [PATCH] Link to virdbustest against DBus libs

[Daniel P. Berrange]

On Tue, Aug 13, 2013 at 02:23:41PM +0200, Guido Günther wrote:
> On Tue, Aug 13, 2013 at 09:51:22AM +0100, Daniel P. Berrange wrote:
> > On Mon, Aug 12, 2013 at 10:13:07PM +0200, Guido Günther wrote:
> > > On Mon, Aug 12, 2013 at 01:21:08PM -0600, Eric Blake wrote:
> > > > On 08/12/2013 01:14 PM, Guido Günther wrote:
> > > > > otherwise we fail like:
> > > > > 
> > > > >     CCLD     virdbustest
> > > > >     /usr/bin/ld: virdbustest-virdbustest.o: undefined reference to symbol 'dbus_message_unref'
> > > > >     /lib/x86_64-linux-gnu/libdbus-1.so.3: error adding symbols: DSO missing from command line
> > > > >     collect2: error: ld returned 1 exit status
> > > > > 
> > > > > Found by:
> > > > > 
> > > > >     http://honk.sigxcpu.org:8001/job/libvirt-build-debian-sid-amd64/7/console
> > > > > ---
> > > > >  tests/Makefile.am | 2 +-
> > > > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > > > 
> > > > ACK.
> > > 
> > > I found several more places which fail to link with a strict
> > > --no-copy-dt-needed-entries. See my followup patch which superseeds this
> > > one.
> > 
> > Hmm, it sounds like we ought to make configure.ac automatically
> > add this linker flag if we can detect that it is supported.
> > 
> 
> Does this make sense:
> 
> Subject: [PATCH] Check for --no-copy-dt-needed linker flag
> 
> and use it when available
> ---
>  configure.ac            |  1 +
>  m4/virt-linker-relro.m4 | 11 +++++++++++
>  src/Makefile.am         |  9 +++++++++
>  tests/Makefile.am       |  1 +
>  4 files changed, 22 insertions(+)
> 
> diff --git a/configure.ac b/configure.ac
> index ac8cfa1..2084437 100644
> --- a/configure.ac
> +++ b/configure.ac
> @@ -160,6 +160,7 @@ AC_MSG_RESULT([$VERSION_SCRIPT_FLAGS])
>  LIBVIRT_COMPILE_WARNINGS
>  LIBVIRT_COMPILE_PIE
>  LIBVIRT_LINKER_RELRO
> +LIBVIRT_LINKER_NO_COPY_DT_NEEDED_ENTRIES
>  
>  LIBVIRT_CHECK_APPARMOR
>  LIBVIRT_CHECK_ATTR
> diff --git a/m4/virt-linker-relro.m4 b/m4/virt-linker-relro.m4
> index 9bca90e..57b3d03 100644
> --- a/m4/virt-linker-relro.m4
> +++ b/m4/virt-linker-relro.m4
> @@ -30,3 +30,14 @@ AC_DEFUN([LIBVIRT_LINKER_RELRO],[
>  
>      AC_MSG_RESULT([$RELRO_LDFLAGS])
>  ])
> +
> +AC_DEFUN([LIBVIRT_LINKER_NO_COPY_DT_NEEDED_ENTRIES],[
> +    AC_MSG_CHECKING([for how to avoid indirect lib deps])
> +
> +    NO_COPY_DT_NEEDED_ENTRIES_LDFLAGS=
> +    `$LD --help 2>&1 | grep -- "--no-copy-dt-needed-entries" >/dev/null` && \
> +        NO_COPY_DT_NEEDED_ENTRIES_LDFLAGS="-Wl,--no-copy-dt-needed-entries"
> +    AC_SUBST([NO_COPY_DT_NEEDED_ENTRIES_LDFLAGS])
> +
> +    AC_MSG_RESULT([$NO_COPY_DT_NEEDED_ENTRIES_LDFLAGS])
> +])

This doesn't belong in this file. Create a new virt-linker-no-indirect.m4
file for it.

The variable / macro names are rather too long too - use something
like   NO_INDIRECT_LDFLAGS / LIBVIRT_LINKER_NO_INDIRECT respectively.

Daniel
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