linking libjava.so RPATH problem

[Tom Schutter]

On 7/5/05, Vasil Dimov <vd at datamax.bg> wrote:
> On Tue, Jul 05, 2005 at 03:55:26PM -0600, Tom Schutter wrote:
> > I am having problems linking in the Java JVM libraries (libjava.so,
> > libverify.so, libjvm.so) into my executable.
> >
> > With these options added to my gcc command:
> >  -L/usr/local/jdk1.4.2/jre/lib/i386 -ljava -lverify
> >  -L/usr/local/jdk1.4.2/jre/lib/i386/server -ljvm
> >
> > It links ok, but when I try to run it I get:
> > $ ./testme
> > /libexec/ld-elf.so.1: Shared object "libjava.so" not found, required by
> > "testme"
> >
> > At this point ldd tells me:
> > $ ldd testme
> > testme:
> >        libm.so.3 =3D> /lib/libm.so.3 (0x2807c000)
> >        libjava.so =3D> not found (0x0)
> >        libverify.so =3D> not found (0x0)
> >        libjvm.so =3D> not found (0x0)
> >        libpthread.so.1 =3D> /usr/lib/libpthread.so.1 (0x28097000)
> >        libc.so.5 =3D> /lib/libc.so.5 (0x280bb000)
> >
> > Using -Xlinker -rpath -Xlinker PATH_TO_JRE_DIR, I can tell my executable to
> > look in the JRE dir for libjvm.so.  I have verified that RPATH has been set
> > in the executable using objdump:
> > $ objdump -x testme | grep RPATH
> >  RPATH       /usr/local/jdk1.4.2/jre/lib/i386:/usr/local/jdk1.4.2/jre/lib/i386/server
> >
> > But when I run the executable, it cannot find libjvm.so:
> > $ ./testme
> > /libexec/ld-elf.so.1: Shared object "libjvm.so" not found, required by
> > "libjava.so"
> >
> > At this point ldd tells me:
> > $ ldd ./testme
> > ./testme:
> >        libm.so.3 =3D> /lib/libm.so.3 (0x2807c000)
> >        libjava.so =3D> /usr/local/jdk1.4.2/jre/lib/i386/libjava.so (0x28097000)
> >        libverify.so =3D> /usr/local/jdk1.4.2/jre/lib/i386/libverify.so
> > (0x280b5000)
> >        libjvm.so =3D>
> > /usr/local/jdk1.4.2/jre/lib/i386/server/libjvm.so (0x280ca000)
> >        libpthread.so.1 =3D> /usr/lib/libpthread.so.1 (0x28702000)
> >        libc.so.5 =3D> /lib/libc.so.5 (0x28726000)
> >        libjvm.so =3D> not found (0x0)
> >        libverify.so =3D> not found (0x0)
> >        libjvm.so =3D> not found (0x0)
> >        libstdc++.so.4 =3D> /usr/lib/libstdc++.so.4 (0x28800000)
> >
> > Note that at this point on Linux, testme runs ok.
> >
> > If I set LD_LIBRARY_PATH, the libraries are found (no output is correct):
> > $ LD_LIBRARY_PATH=3D/usr/local/jdk1.4.2/jre/lib/i386:/usr/local/jdk1.4.2/jre/lib/i386/server
> > ./testme
> > $
> >
> > My questions are:
> >
> > 1) Why is the RPATH in the executable being ignored?
> 
> Here are my suggestions:
> 
> It is not being ignored, as you see: libjava.so, libverify.so and
> libjvm.so were found in /usr/local/jdk1.4.2/jre/lib/i386/
> 
> > 2) When I add the -rpath, I get two copies of a libjvm.so reference in testme,
> >   one that resolves correctly, and one that doesn't.  Why?
> 
> What happens is that libjava.so "depends" on libjvm.so and libverify.so
> itself:
> % ldd /usr/local/jdk1.4.2/jre/lib/i386/libjava.so
> /usr/local/jdk1.4.2/jre/lib/i386/libjava.so:
>         libjvm.so => not found (0x0)
>         libverify.so => not found (0x0)
> 
> and libverify.so "depends" on libjvm.so itself:
> % ldd /usr/local/jdk1.4.2/jre/lib/i386/libverify.so
> /usr/local/jdk1.4.2/jre/lib/i386/libverify.so:
>         libjvm.so => not found (0x0)
> 
> So, after finding libjava.so, libverify.so and libjvm.so, required by
> "testme" executable (thanks to its RPATH) the linker sees that
> libjava.so itself depends on libjvm.so and libverify.so and:
> 1. does not notice that they are already found/loaded
> 2. does not use the rpath in "testme"
> 3. starts looking for them in the standard path and does not find them
> 
> > 3) What is the correct way of linking in libjvm.so?
> 
> In my point of view the libjava.so and libverify.so shared objects are
> incorrect in the way that they depend on some shared objects, that are
> not located in the standard path *AND* libjava.so and libverify.so do
> not have RPATH in themselves.
> 
> 1. Recompile libjava.so and libverify.so without -L... -l..., it is not
> needed anyway.
> OR
> 2. Recompile libjava.so and libverify.so with -L... -l..., but also add
> -rpath
> OR
> 3. Use ldconfig -m (see ldconfig_paths in rc.conf(5))
> OR
> 4. Use LD_LIBRARY_PATH
> 
> > Thanks,
> > --
> > Tom Schutter

This is making more sense now.

1) Does the fact that the linker does not realize that the libraries
have already been found indicate a bug in the linker?  If so, how do I
best report it?

2) Because libjava.so and libverify.so were compiled by the java/jdk14
port, your suggestions on recompiling those libraries should be done
within that framework.  (This part is for you Alexey).

3) For now, I will try using ldconfig, but I think that the better
solution is to fix the creation of the shared libraries.

-- 
Tom Schutter