Re: [Qemu-devel] undefined symbol _nettle_cast5_set_key

["Daniel P. Berrange" <berrange@redhat.com>]

On Thu, Jun 02, 2016 at 01:01:46PM -0400, Programmingkid wrote:
> 
> On May 31, 2016, at 12:00 PM, Daniel P. Berrange wrote:
> 
> > On Tue, May 31, 2016 at 11:48:45AM -0400, Programmingkid wrote:
> >> 
> >> On May 31, 2016, at 10:51 AM, Daniel P. Berrange wrote:
> >>>> gcc-4.9 -I/opt/local/include/pixman-1 -I/Users/john/Documents/Development/Projects/Qemu/qemu-git/dtc/libfdt -m64 -DOS_OBJECT_USE_OBJC=0 -arch x86_64 -D_GNU_SOURCE -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -Wstrict-prototypes -Wredundant-decls -Wall -Wundef -Wwrite-strings -Wmissing-prototypes -fno-strict-aliasing -fno-common  -Wendif-labels -Wmissing-include-dirs -Wempty-body -Wnested-externs -Wformat-security -Wformat-y2k -Winit-self -Wignored-qualifiers -Wold-style-declaration -Wold-style-definition -Wtype-limits -fstack-protector-strong -I/usr/local/Cellar/gnutls/3.4.11/include -I/usr/local/Cellar/nettle/3.2/include -I/usr/local/Cellar/libtasn1/4.8/include -I/opt/local/include -I/usr/local/Cellar/nettle/3.2/include   -I/opt/local/include/libpng16 -I/usr/local/Cellar/libusb/1.0.20/include/libusb-1.0 -I/usr/local/Cellar/usbredir/0.7.1/include -I/Users/john/Documents/Development/Projects/Qemu/qemu-git/tests -O2 -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=2 -D_REENTRANT -I/usr/local/Cellar/glib/2.46.2/include/glib-2.0 -I/usr/local/Cellar/glib/2.46.2/lib/glib-2.0/include -I/usr/local/opt/gettext/include -g  -m64 -framework CoreFoundation -framework IOKit -arch x86_64 -g  -o qemu-nbd qemu-nbd.o async.o thread-pool.o block.o blockjob.o main-loop.o iohandler.o qemu-timer.o aio-posix.o qemu-io-cmds.o block/raw_bsd.o block/qcow.o block/vdi.o block/vmdk.o block/cloop.o block/bochs.o block/vpc.o block/vvfat.o block/qcow2.o block/qcow2-refcount.o block/qcow2-cluster.o block/qcow2-snapshot.o block/qcow2-cache.o block/qed.o block/qed-gencb.o block/qed-l2-cache.o block/qed-table.o block/qed-cluster.o block/qed-check.o block/vhdx.o block/vhdx-endian.o block/vhdx-log.o block/quorum.o block/parallels.o block/blkdebug.o block/blkverify.o block/blkreplay.o block/block-backend.o block/snapshot.o block/qapi.o block/raw-posix.o block/null.o block/mirror.o block/io.o block/throttle-groups.o block/nbd.o block/nbd-client.o block/sheepdog.o block/accounting.o block/dirty-bitmap.o block/write-threshold.o block/crypto.o nbd/server.o nbd/client.o nbd/common.o block/curl.o block/dmg.o crypto/init.o crypto/hash.o crypto/aes.o crypto/desrfb.o crypto/cipher.o crypto/tlscreds.o crypto/tlscredsanon.o crypto/tlscredsx509.o crypto/tlssession.o crypto/secret.o crypto/random-gnutls.o crypto/pbkdf.o crypto/pbkdf-nettle.o crypto/ivgen.o crypto/ivgen-essiv.o crypto/ivgen-plain.o crypto/ivgen-plain64.o crypto/afsplit.o crypto/xts.o crypto/block.o crypto/block-qcow.o crypto/block-luks.o io/channel.o io/channel-buffer.o io/channel-command.o io/channel-file.o io/channel-socket.o io/channel-tls.o io/channel-watch.o io/channel-websock.o io/channel-util.o io/task.o qom/object.o qom/container.o qom/qom-qobject.o qom/object_interfaces.o  libqemuutil.a libqemustub.a  -lz -L/opt/local/lib -lcurl -lbz2 -L/usr/local/Cellar/glib/2.46.2/lib -L/usr/local/opt/gettext/lib -lgthread-2.0 -lglib-2.0 -lintl  -lz -lz -L/usr/local/Cellar/nettle/3.2/lib -lnettle -L/usr/local/Cellar/gnutls/3.4.11/lib -lgnutls  -lutil
> >>>> Undefined symbols for architecture x86_64:
> >>>> "_nettle_cast5_set_key", referenced from:
> >>>>     _qcrypto_cipher_new in cipher.o
> >>>> ld: symbol(s) not found for architecture x86_64
> >>>> collect2: error: ld returned 1 exit status
> >>>> make: *** [qemu-nbd] Error 1
> >>> 
> >>> This linker line again looks basically sound. It is still passing the
> >>> correct -lnettle arg, and the -I and -L args to point to the nettle
> >>> 3.2 installation.
> >>> 
> >>> Given that we found the "KDF" support in nettle, we know that it is
> >>> new enough to support the "nettle_cast5_set_key" function too so
> >>> we ought to link correctly.
> >>> 
> >>> The only thing that occurs to me is that we have a number of other
> >>> -L args present - eg -L/opt/local/lib.
> >>> 
> >>> I wonder if one of those  other search paths has a differnet version
> >>> of nettle installed in it, causing gcc to link to the wrong one.
> >> 
> >> I did a search and found libnettle.4.7.dylib in /opt/local/lib. I
> >> also found libnettle.6.2.dylib in /usr/local/Cellar/nettle/3.2/lib.
> > 
> > Ah ha, that sounds like it could well be the cause of the problems.
> > 
> > I'm not sure if there's a reason you have nettle in both /opt/local/lib
> > and /usr/local/Cellar/nettle/3.2/lib.  The -L/opt/local/lib arg appears
> > before the -L/usr/loca/Cellar/nettle/3.2/lib arg, so I expect that means
> > it will be picking up the older libnettle.4.7.dylib first :-(
> > 
> > Changing the order of the -L arg that QEMU uses is not exactly a
> > straightforward / practical thing todo. If its possible for you
> > to get rid of the older 4.7.dylib file i expect that would fix
> > the QEMU build, but not sure if that'll break something else on
> > your OS-X system.
> > 
> > I'm not really sure there's much we can do to detect this problem
> > in QEMU's configure script either. The config.log file seems to
> > show that at the time we probe for nettle & test linking with it,
> > we've not yet detected the later that uses -L/opt/local/lib.
> 
> Maybe we can change things so that we only use the highest version of nettle detected.

AFAIK, it is the linker that would have todo that, not something under
our direct control. We just tell the linker what directories to look
in and in your case you have different copies of the same lib in multiple
places and the linker picks the first that it finds.

> Nettle is a library that deals with cryptography which I don't need or use. Is there a way to turn off its inclusion into QEMU?

Of course, you can always use the --disable-nettle flag to configure
or force use of gcrypt instead with --enable-gcrypt

Regards,
Daniel
-- 
|: http://berrange.com      -o-    http://www.flickr.com/photos/dberrange/ :|
|: http://libvirt.org              -o-             http://virt-manager.org :|
|: http://autobuild.org       -o-         http://search.cpan.org/~danberr/ :|
|: http://entangle-photo.org       -o-       http://live.gnome.org/gtk-vnc :|