Re: Problem with removing atexit.

[Ben Collins <bcollins at debian dot org>]

On Tue, May 01, 2001 at 09:42:05AM -0700, H . J . Lu wrote:
> On Tue, May 01, 2001 at 12:28:15PM -0400, Ben Collins wrote:
> > On Tue, May 01, 2001 at 09:20:56AM -0700, H . J . Lu wrote:
> > > On Tue, May 01, 2001 at 11:52:45AM -0400, Ben Collins wrote:
> > > > > 
> > > > > Now, the question is, do we provide backward binary compatibility to
> > > > > DSOs built against glibc 2.0.x? Any comments?
> > > > 
> > > > This seems to be the same problem I ran into on non-i386, with a gcc
> > > > that didn't have the weaksym patch. It's not a compatibility problem,
> > > > it's a bug in gcc. The DSO's need to be recompiled with a recent gcc
> > > > (2.95.4 from CVS, or gcc-3.x)
> > > 
> > > If you have to recompile a DSO to work with glibc 2.2.3, it IS a
> > > compatibility issue. My question is, should we require people to
> > > recompile DSOs with a right gcc if they want to use glibc 2.2.3?
> > > I don't think we should. But I don't have a good solution at hand
> > > for this problem.
> > 
> > You have to recompile it only because it was compiled with a buggy gcc.
> > This isn't a compatibility issue any more than it is to not link with
> > -lc and thus not include libc_nonshared.a into libraries.
> > 
> 
> Wrong. Read my emails and think about it again. The problem is the
> current symbol version scheme doesn't provide the backward run-time
> binary compatibility for DSOs compiled without symbol version when
> we remove a default symbol.

I just tried running a bash that was compiled against glibc 2.0.7t
(along with a libncurses.so.3.4 and libreadline.so.2, also compiled
against 2.0.7t) and it worked fine.

$ objdump --dynamic-syms tmp/lib/libncurses.so.3.4 | grep atexit
00000000      DF *UND*  0000003e atexit
$ objdump --dynamic-syms /lib/libc-2.2.3.so | grep atexit
00019430 l    d  .rel__libc_atexit      00000000
0010c66c l    d  __libc_atexit  00000000
0002f110 g    DF .text  00000034 (GLIBC_2.0)  atexit
0002ef50 g    DF .text  00000048  GLIBC_2.1.3 __cxa_atexit
$ ldd tmp/bin/bash
        libreadline.so.2 => /home/bcollins/tmp/lib/libreadline.so.2 (0x40017000)
        libncurses.so.3.4 => /home/bcollins/tmp/lib/libncurses.so.3.4 (0x40042000)
        libdl.so.2 => /lib/libdl.so.2 (0x4008b000)
        libc.so.6 => /lib/libc.so.6 (0x4008f000)
        /lib/ld-linux.so.2 => /lib/ld-linux.so.2 (0x40000000)
$ ./tmp/bin/bash -c "echo hello"
hello
$ 

Are you absolutely sure this is a compatibility issue and not a toolchain
issue?

-- 
 -----------=======-=-======-=========-----------=====------------=-=------
/  Ben Collins  --  ...on that fantastic voyage...  --  Debian GNU/Linux   \
`  bcollins@debian.org  --  bcollins@openldap.org  --  bcollins@linux.com  '
 `---=========------=======-------------=-=-----=-===-======-------=--=---'