Re: auto-solib-add when attaching to inferior

["Kris Warkentin" <kewarken at qnx dot com>]

> > Remember that you don't use attach with the normal remote protocol.
> > When you to_open the target has already started.  For your agent it
> > sounds like you need to do it at to_attach time; but why isn't the one
> > in infcmd.c:attach_command working?
>
> Good question.  For some reason locate_base() seems to be failing.  Maybe
> that's the answer to the puzzle.  It looks like the SOLIB_ADD() in
> attach_command() should do the right thing.  I'll chase it deeper from
that
> end.

Well, I think I've found the cause but only part of the solution.  When
solib-svr4.c:elf_locate_base() is called, the dynamic pointer stored in the
DT_DEBUG section is zero.  This is because QNX has a util called 'on' which
can spawn a process in a 'held' state where it's stopped on the very first
instruction.  This is handy if you want to attach to a process before it
gets going but in this case, the loader hasn't been run yet so the DT_DEBUG
section isn't filled in.  If I attach to a process that is running properly,
I get my solibs loaded up and everything is fine.

This, however, presents the next problem: the shlib_event breakpoint not
being set.  On our native gdb, if I just add a SOLIB_CREATE_INFERIOR_HOOK
call to the attach function, it works properly.  The remote is another case.
I'm still thinking it's a sync issue with the debug agent though.

Thanks for the help.  You definitely got me barking up the right tree.

cheers,

Kris