Re: [RFA] Find and read symbol files after attach (linux)

[Daniel Jacobowitz <dmj+@andrew.cmu.edu>]

On Tue, Jan 08, 2002 at 09:58:06AM -0800, Michael Snyder wrote:
> Daniel Jacobowitz wrote:
> > 
> > On Mon, Jan 07, 2002 at 04:40:00PM -0800, Michael Snyder wrote:
> > > [oops, hit send too soon...]
> > > This change allows GDB to find and read the symbol files (including
> > > all shared libraries) on Linux when you attach to an anonymous PID.
> > > It should work for all Linuxen, but for now I've only added it to the
> > > linux.mh and nm-linux.h files in config/i386.  Please feel free to
> > > add it to your targets.
> > 
> > [without actually looking at it...]
> > 
> > (A) Is there any reason not to do it for all Linuxen in
> > config/nm-linux.h?
> 
> Probably can.  I was being conservative.

I'd prefer you to do this, then.  I believe it will work.

> > (B) Why do we need /proc to do this?  We should be able to use the
> > information in the link map - which we already access in solib-svr4.h -
> > to get all of this.
> 
> There may be another method of doing it -- I just used the
> method I know (copied from Solaris).  We need to discover
> the mapped memory regions so you can find the "debug_base".
> But this isn't one of my strong areas, so you may well know
> a better way to do the same thing.

Well, Mark's comment is completely correct.  Eventually I remembered
that this works by looking up data at _DYNAMIC, which means we need the
executable first :)

I believe that we should be able to find the rest of what we need by
the shared library code, without the mappings file, though.  I also
thought that this would just 'work'.  Have you tried with the code to
find the executable but without the code to find shared libraries? 
What happens?

-- 
Daniel Jacobowitz                           Carnegie Mellon University
MontaVista Software                         Debian GNU/Linux Developer