[RFC PATCH 0/3] implement dlmopen hooks for gdb

[H.J. Lu]

On Wed, Jul 28, 2021 at 11:34 AM Daniel Walker via Libc-alpha
<libc-alpha@sourceware.org> wrote:
>
> On Fri, Sep 18, 2020 at 05:40:30PM +0200, Florian Weimer wrote:
> > * Daniel Walker:
> >
> > > On Thu, Sep 17, 2020 at 09:53:30AM -0400, Carlos O'Donell wrote:
> > >> On 9/17/20 8:59 AM, Florian Weimer wrote:
> > >> > * Carlos O'Donell:
> > >> >
> > >> >> You will always have .dynsym with a definition for _r_debug_dlmopen.
> > >> >
> > >> > Note that this doesn't work if you just have a core file.  In order to
> > >> > find _r_debug (or _r_debug_dlmopen), a debugger needs the exact same
> > >> > copy of ld.so that was used by the executable, otherwise the symbol
> > >> > cannot be found in the image.
> > >>
> > >> You are correct.
> > >>
> > >> I followed up on my own email regarding this.
> > >>
> > >> So in the end to get process and core file debugging we'll need:
> > >>
> > >> * _r_debug_dlmopen
> > >> * DT_DEBUG_DLMOPEN
> > >>
> > >
> > > It seems like adding DT_DEBUG_DLMOPEN into the gABI might take some
> > > effort. Have you considered this ? The last one which was added was
> > > DT_SYMTAB_SHNDX in 2018, and it looks like it did not come from glibc.
> >
> > We are reviving GNU gABI maintenance.  There's been quite a bit of list
> > activity, and a proposal of a first ABI document:
> >
> >   <https://sourceware.org/pipermail/gnu-gabi/2020q3/thread.html>
> >
> > I have a feeling that we might be soon over this bump, and getting
> > things added should become easier.
> >
> > In the meantime, can we demo this feature without DT_DEBUG_DLMOPEN?
> > With a patch glibc and gdb?  Incidentally, I have an LD_AUDIT issue I
> > need to debug. 8-)
>
> Do you know what the status of taking over the gABI is ?

Cary made an announcement last August:

https://groups.google.com/g/generic-abi/c/9OO5vhxb00Y/m/D-PCPis_CAAJ

But I didn't see the github URL.

-- 
H.J.