Re: [davidm@napali.hpl.hp.com: readelf question]

[Daniel Jacobowitz <drow@mvista.com>]

On Tue, Jun 17, 2003 at 01:44:40PM -0700, Roland McGrath wrote:
> >   Andrew> Last I heard was a kernel patch to make auxv info available
> >   Andrew> in the core file, and via the /proc and ptrace interfaces.
> > 
> > Yes: auxv, core, and ptrace are there.  I don't think /proc support is
> > there.  Not sure if Roland is planning to do something about that.
> 
> To clarify, I think what David's saying (and what I think is the case) is
> that access to these memory regions via core dumps and ptrace does work
> just like any other user address, and that the startup-time aux vector on a
> process's stack contains AT_SYSINFO_EHDR to tell the process the location.
> 
> The piece that still remains missing is gdb finding out where the DSO is,
> i.e. the AT_SYSINFO_EHDR value of a traced process.  For that, I've
> proposed a new /proc/PID/auxv virtual file and a new NT_AUXV note in core
> dumps (these match exactly what Solaris provides).  I posted a patch to
> implement this in Linux 2.5 to lkml on May 15; it was met with resounding
> silence.  Pushing that patch has not been top priority since then, since
> this issue affects gdb only with 2.5 kernels and so is not an imminent
> concern for the Red Hat products I work on.  
> 
> After posting that patch, I realized it had a leak.  I didn't bother to
> follow up with the corrected patch immediately, since my posting of the
> first patch had failed to solicit any response of any kind even on the
> question of the interface.  I would be happy to dust off that patch and
> send it to you, post it again, or send it anywhere else that would increase
> the likelihood of getting some response about it.  If Linux kernel folks
> are happy enough with the interface but not with the implementation, I
> would be glad to rewrite it as requested.  

Send me a copy of the update, please.  I'm going to push another
debug-related patch to Linus this week anyway.  He's been pretty good
about taking patches lately.

-- 
Daniel Jacobowitz
MontaVista Software                         Debian GNU/Linux Developer