[Libguestfs] [PATCH 4/4] java: Link with gnulib to resolve missing hash_free symbol.

[Richard W.M. Jones]

On Wed, Aug 22, 2018 at 12:56:47PM +0200, Pino Toscano wrote:
> On Tuesday, 14 August 2018 15:42:13 CEST Richard W.M. Jones wrote:
> > ---
> >  java/Makefile.am | 3 ++-
> >  1 file changed, 2 insertions(+), 1 deletion(-)
> > 
> > diff --git a/java/Makefile.am b/java/Makefile.am
> > index 81c20f266..1bad9a853 100644
> > --- a/java/Makefile.am
> > +++ b/java/Makefile.am
> > @@ -122,7 +122,8 @@ libguestfs_jni_la_CFLAGS = \
> >  libguestfs_jni_la_LIBADD = \
> >  	$(top_builddir)/common/structs/libstructs.la \
> >  	$(top_builddir)/common/utils/libutils.la \
> > -	$(top_builddir)/lib/libguestfs.la
> > +	$(top_builddir)/lib/libguestfs.la \
> > +	$(top_builddir)/gnulib/lib/libgnu.la
> 
> Hmm what's the exact error in this case? On which platform?

Fedora 28:

Exception in thread "main" java.lang.UnsatisfiedLinkError: /home/rjones/d/libguestfs-master/java/.libs/libguestfs_jni.so.1.39.8: /home/rjones/d/libguestfs-master/java/.libs/libguestfs_jni.so.1.39.8: undefined symbol: hash_free
        at java.lang.ClassLoader$NativeLibrary.load(Native Method)
        at java.lang.ClassLoader.loadLibrary0(ClassLoader.java:1941)
        at java.lang.ClassLoader.loadLibrary(ClassLoader.java:1857)
        at java.lang.Runtime.loadLibrary0(Runtime.java:870)
        at java.lang.System.loadLibrary(System.java:1122)
        at com.redhat.et.libguestfs.GuestFS.<clinit>(GuestFS.java:51)
        at Bindtests.main(Bindtests.java:33)

> The java binding does not explicitly use the hash stuff from gnulib.

It uses the CLEANUP_* macros, and they appear to pull in the hash_free
function (via guestfs_int_cleanup_hash_free).

What does confuse me is why linking with libutils.a causes the
hash_free dependency to be pulled in, since if my understanding of
static linking is correct it should only pull in whole object files
which are actually used.  This I cannot explain.

Nevertheless the error message (see above) is repeatable and
undeniable evidence that something is wrong.

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
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