Re: [libvirt] [PATCHv2] 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. Assume that the switch to gnutls 3.0 is a reliable witness, when pkg-config is present; otherwise be pessimistic and use gcrypt. * 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; --- v2: use second pkg-config invocation rather than ldd to determine whether gnutls uses gcrypt configure.ac | 27 +++++++++++++++++++-------- libvirt.spec.in | 2 ++ src/libvirt.c | 10 ++++++---- 3 files changed, 27 insertions(+), 12 deletions(-) diff --git a/configure.ac b/configure.ac index cc9942a..eb56b63 100644 --- a/configure.ac +++ b/configure.ac @@ -1076,12 +1076,19 @@ if test "x$with_gnutls" != "xno"; then LIBS="$LIBS $GNUTLS_LIBS" GNUTLS_FOUND=no + GNUTLS_GCRYPT=no if test -x "$PKG_CONFIG" ; then + dnl double probe, since we know that gnutls 3.0 switched to nettle instead of + dnl gcrypt PKG_CHECK_MODULES(GNUTLS, gnutls >= $GNUTLS_REQUIRED, - [GNUTLS_FOUND=yes], [GNUTLS_FOUND=no]) + [GNUTLS_FOUND=yes + PKG_CHECK_MODULES([GNUTLS], [gnutls >= 3.0], [], [GNUTLS_GCRYPT=yes])], + [GNUTLS_FOUND=no]) fi if test "$GNUTLS_FOUND" = "no"; then + dnl pkg-config couldn't help us, assume gcrypt is necessary fail=0 + GNUTLS_GCRYPT=yes AC_CHECK_HEADER([gnutls/gnutls.h], [], [fail=1]) AC_CHECK_LIB([gnutls], [gnutls_handshake],[], [fail=1], [-lgcrypt]) @@ -1098,13 +1105,17 @@ 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="$GNUTLS_CFLAGS -DGCRYPT_NO_DEPRECATED" + dnl If gnutls linked against -lgcrypt, then we must initialize gcrypt + dnl prior to using gnutls. Newer versions of gnutls use -lnettle, in + dnl which case we don't want to drag in gcrypt ourselves. + if test "$GNUTLS_GCRYPT" = yes; then + 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" + AC_DEFINE_UNQUOTED([WITH_GNUTLS_GCRYPT], 1, + [set to 1 if it is known or assumed that GNUTLS uses gcrypt]) + fi dnl gnutls 3.x moved some declarations to a new header AC_CHECK_HEADERS([gnutls/crypto.h], [], [], [[ diff --git a/libvirt.spec.in b/libvirt.spec.in index e0e0004..4320281 100644 --- a/libvirt.spec.in +++ b/libvirt.spec.in @@ -422,7 +422,9 @@ BuildRequires: readline-devel BuildRequires: ncurses-devel BuildRequires: gettext BuildRequires: libtasn1-devel +%if (0%{?rhel} && 0%{?rhel} < 7) || (0%{?fedora} && 0%{?fedora} < 19) BuildRequires: libgcrypt-devel +%endif BuildRequires: gnutls-devel BuildRequires: libattr-devel %if %{with_libvirtd} diff --git a/src/libvirt.c b/src/libvirt.c index 8157488..66e8248 100644 --- a/src/libvirt.c +++ b/src/libvirt.c @@ -55,7 +55,9 @@ #include "intprops.h" #include "virconf.h" #if WITH_GNUTLS -# include <gcrypt.h> +# if WITH_GNUTLS_GCRYPT +# include <gcrypt.h> +# endif # include "rpc/virnettlscontext.h" #endif #include "vircommand.h" @@ -270,7 +272,7 @@ winsock_init(void) #endif -#ifdef WITH_GNUTLS +#ifdef WITH_GNUTLS_GCRYPT static int virTLSMutexInit(void **priv) { virMutexPtr lock = NULL; @@ -323,7 +325,7 @@ static struct gcry_thread_cbs virTLSThreadImpl = { virTLSMutexUnlock, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL }; -#endif +#endif /* WITH_GNUTLS_GCRYPT */ /* Helper macros to implement VIR_DOMAIN_DEBUG using just C99. This * assumes you pass fewer than 15 arguments to VIR_DOMAIN_DEBUG, but @@ -407,7 +409,7 @@ virGlobalInit(void) virErrorInitialize() < 0) goto error; -#ifdef WITH_GNUTLS +#ifdef WITH_GNUTLS_GCRYPT /* * This sequence of API calls it copied exactly from * gnutls 2.12.23 source lib/gcrypt/init.c, with -- 1.8.3.1 -- libvir-list mailing list libvir-list(a)redhat.com https://www.redhat.com/mailman/listinfo/libvir-list