[glibc] dlfcn: Implement the RTLD_DI_PHDR request type for dlinfo

[Florian Weimer]

* Florian Weimer via Glibc-cvs:

> https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=d056c212130280c0a54d9a4f72170ec621b70ce5
>
> commit d056c212130280c0a54d9a4f72170ec621b70ce5
> Author: Florian Weimer <fweimer@redhat.com>
> Date:   Fri Apr 29 17:00:53 2022 +0200
>
>     dlfcn: Implement the RTLD_DI_PHDR request type for dlinfo
>     
>     The information is theoretically available via dl_iterate_phdr as
>     well, but that approach is very slow if there are many shared
>     objects.
>     
>     Reviewed-by: Carlos O'Donell <carlos@redhat.com>
>     Tested-by: Carlos O'Donell <carlos@rehdat.com>
>
> Diff:
> ---
>  dlfcn/Makefile          |   4 ++
>  dlfcn/dlfcn.h           |   7 ++-
>  dlfcn/dlinfo.c          |  13 ++++-
>  dlfcn/tst-dlinfo-phdr.c | 125 ++++++++++++++++++++++++++++++++++++++++++++++++
>  manual/dynlink.texi     |  15 ++++--
>  5 files changed, 159 insertions(+), 5 deletions(-)

I plan to backport this to 2.35 and 2.34 next week because it
complements the audit fixes.

Thanks,
Florian