On Tue, May 19, 2020 at 04:32:38PM +0200, Geert Uytterhoeven wrote:

Hi Christian,

On Tue, May 19, 2020 at 3:15 PM Christian Brauner
[off-list ref] wrote:

quoted

On Tue, May 19, 2020 at 06:56:36AM -0500, Eric W. Biederman wrote:

quoted

Andreas Schwab [off-list ref] writes:

quoted

On Mai 18 2020, Eric W. Biederman wrote:

quoted

If it was only libc4 and libc5 that used the uselib system call then it
can probably be removed after enough time.

Only libc4 used it, libc5 was already ELF.

binfmt_elf.c supports uselib.  In a very a.out ish way.  Do you know if
that support was ever used?

If we are truly talking a.out only we should be able to make uselib
conditional on a.out support in the kernel which is strongly mostly
disabled at this point.

The only ones that even allow setting AOUT:

arch/alpha/Kconfig:     select HAVE_AOUT
arch/m68k/Kconfig:      select HAVE_AOUT if MMU

and x86 deprecated it March 2019:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=eac616557050737a8d6ef6fe0322d0980ff0ffde

Quoting myself (for the second time this month):
   "I think it's safe to assume no one still runs a.out binaries on m68k."
    http://lore.kernel.org/r/CAMuHMdW+m0Q+j3rsQdMXnrEPm+XB5Y2AQrxW5sD1mZAKgmEqoA@mail.gmail.com (local)

Well, it's just a great thing to hear. :)

Fyi, I once tried to give a demo with a Slackware version in a container
which pre-dated ELF on a x86 kernel with AOUT. It didn't go well...

Christian