Re: [libvirt] [PATCH] build: avoid -lgcrypt with newer gnutls

https://bugzilla.redhat.com/show_bug.cgi?id=951637 Newer gnutls uses nettle, rather than gcrypt, which is a lot nicer regarding initialization. Yet we were unconditionally initializing gcrypt even when gnutls wouldn't be using it, and having two crypto libraries linked into libvirt.so is pointless. The ldd probe in configure borrows from our libnl-1 vs. libnl-3 code. * configure.ac (WITH_GNUTLS): Probe whether to add -lgcrypt, and define a witness WITH_GNUTLS_GCRYPT. * src/libvirt.c (virTLSMutexInit, virTLSMutexDestroy) (virTLSMutexLock, virTLSMutexUnlock, virTLSThreadImpl) (virGlobalInit): Honor the witness. * libvirt.spec.in (BuildRequires): Make gcrypt usage conditional, no longer needed in Fedora 19. Signed-off-by: Eric Blake <eblake(a)redhat.com&gt; --- Tested with 'ldd src/.libs/libvirt.so | grep -E "(gcry|net|tls)"': - on RHEL 6.4 and Fedora 18, pre- and post-patch remain unchanged (use of just libgnutls/libgcrypt) - on Fedora 19, pre-patch linked against libgnutls, libgcrypt, and libnettle, post-patch linked against just libgnutls and libnettle This should probably go in for 1.1.1, but it's not a build-breaker so it needs review. configure.ac | 27 +++++++++++++++++++++------ libvirt.spec.in | 2 ++ src/libvirt.c | 10 ++++++---- 3 files changed, 29 insertions(+), 10 deletions(-) diff --git a/configure.ac b/configure.ac index cc9942a..de209e2 100644 --- a/configure.ac +++ b/configure.ac @@ -1098,13 +1098,28 @@ if test "x$with_gnutls" != "xno"; then AC_MSG_ERROR([You must install the GnuTLS library in order to compile and run libvirt]) fi else - dnl Not all versions of gnutls include -lgcrypt, and so we add - dnl it explicitly for the calls to gcry_control/check_version - GNUTLS_LIBS="$GNUTLS_LIBS -lgcrypt" - dnl We're not using gcrypt deprecated features so define - dnl GCRYPT_NO_DEPRECATED to avoid deprecated warnings - GNUTLS_CFLAGS="$GNUTLS_CFLAGS -DGCRYPT_NO_DEPRECATED" + dnl If gnutls linked against -lgcrypt, then we must initialize gcrypt + dnl prior to using gnutls. Newer versions of gnutls use -lnettle, in + dnl which case we don't want to drag in gcrypt ourselves. + gnutls_ldd= + for dir in /usr/lib64 /usr/lib /usr/lib/*-linux-gnu*; do + if test -f $dir/libgnutls.so; then + gnutls_ldd=`(ldd $dir/libgnutls.so) 2>&1` + break + fi + done