[patch][rfc] Allow GDB to search for the right libthread_db.so.1

[Paul Pluzhnikov]

On Mon, Apr 20, 2009 at 10:01 AM, Daniel Jacobowitz <drow@false.org> wrote:

>> Could you tell a bit more about this? I thought out set up with
>> multiple incompatible (WRT libthread_db) libc versions was more an
>> exception than the rule.
>
> LinuxThreads and NPTL on the same system.  It's a lot less common now
> - which is why I was going to let the patch fade away instead of
> merging it - but I used to need this regularly.

Oh, right.

If the executable selects LinuxThreads via something like
LD_ASSUME_KERNEL, then GDB must also be invoked with the same, or it
will bind to the wrong libthread_db. And of course "old" static
threaded binaries will continue to use LinuxThreads forever :-(

>> The symbol lookup works for statically linked executables ...
>
> I see.  Do you ship a libthread_db.so alongside a static executable?

Generally we don't ship anything to the outside world (with the
exception of Google search appliance). For our production environment,
we already have several versions of libthread_db.so installed in
known locations, and (with this patch) it's just a matter of iterating
over possible locations until the right libthread_db is found.

-- 
Paul Pluzhnikov