Re: [libvirt] [PATCH] compile: fix undefined reference to gnutls_x509_crt_get_dn with gcc-4.6.1
于 2011年10月18日 22:45, Eric Blake 写道:
On 10/18/2011 02:06 AM, Xu He Jie wrote:
> From: soulxu<soulxu(a)soulxu-ThinkPad-T410.(none)>
>
> When I compile libvirt with gcc-4.6.1 in ubuntu 11.10, got error as
> below:
>
> CCLD libvirtd
> /usr/bin/ld:
> ../src/.libs/libvirt_driver_qemu.a(libvirt_driver_qemu_la-qemu_migration.o):
> undefined reference to symbol 'gnutls_x509_crt_get_dn@@GNUTLS_1_4'
> /usr/bin/ld: note: 'gnutls_x509_crt_get_dn@@GNUTLS_1_4' is defined in
> DSO /usr/lib/x86_64-linux-gnu/libgnutls.so so try adding it to the
> linker command line
> /usr/lib/x86_64-linux-gnu/libgnutls.so: could not read symbols:
> Invalid operation
> collect2: ld returned 1 exit status
> make[3]: *** [libvirtd] Error 1
>
>
> It can compile with gcc-4.5.2 in ubuntu 11.04, but it can not compile
> with gcc-4.6.1 in ubuntu 11.10.
>
> I didn't find reason. Does Anyone know the reason or the different
> between gcc-4.5.2 and gcc-4.6.1?
More likely, the difference is not in gcc, but in ld policy - Ubuntu
recently changed policy to no longer allow implicit link dependencies
by default (that is, if A links against B, and B links against C,
older distros allowed A to use symbols from C without explicitly
linking against C, while newer distros require the explicit link).
>
> I still provide a patch for this. Just make it is working now.
>
> Signed-off-by: soulxu<soulxu(a)soulxu-ThinkPad-T410.(none)>
Just found I
forgot configuring git. The Signed-off-by should be:
Signed-off-by: Xu He Jie <xuhj(a)linux.vnet.ibm.com>
> ---
> src/Makefile.am | 6 +++++-
> 1 files changed, 5 insertions(+), 1 deletions(-)
>
> diff --git a/src/Makefile.am b/src/Makefile.am
> index 87d91ed..104efc6 100644
> --- a/src/Makefile.am
> +++ b/src/Makefile.am
> @@ -776,10 +776,14 @@ noinst_LTLIBRARIES += libvirt_driver_qemu.la
> #libvirt_la_BUILT_LIBADD += libvirt_driver_qemu.la
> endif
> libvirt_driver_qemu_la_CFLAGS = $(NUMACTL_CFLAGS) \
> + $(GNUTLS_CFLAGS) \
> + $(LIBXML_CFLAGS) \
I understand the addition of GNUTLS_CFLAGS, but why LIBXML_CFLAGS? Did
you get a second link error?
Yes, I get a second link error. When I just add
GNUTLS_LIBS to there, I
get another error, as below:
/usr/bin/ld:
../src/.libs/libvirt_driver_qemu.a(libvirt_driver_qemu_la-qemu_domain.o): undefined
reference to symbol 'xmlXPathRegisterNs@(a)LIBXML2_2.4.30'
/usr/bin/ld: note: 'xmlXPathRegisterNs@(a)LIBXML2_2.4.30' is defined in
DSO /usr/lib/libxml2.so so try adding it to the linker command line
/usr/lib/libxml2.so: could not read symbols: Invalid operation
collect2: ld returned 1 exit status
make[3]: *** [libvirtd] Error 1
So I add LIBXML_CFLAGS and LIBXML_LIBS to there too.
> -I@top_srcdir@/src/conf $(AM_CFLAGS)
> libvirt_driver_qemu_la_LDFLAGS = $(AM_LDFLAGS)
> libvirt_driver_qemu_la_LIBADD = $(NUMACTL_LIBS) \
> - $(CAPNG_LIBS)
> + $(CAPNG_LIBS) \
> + $(GNUTLS_LIBS) \
> + $(LIBXML_LIBS)
Likewise.
Your approach to a fix is correct, but I need to know whether to use
the patch as-is or whether we just need one library rather than two.