__ps_strings and compat32

[Joerg Sonnenberger <joerg%britannica.bec.de@localhost>]

Hi all,
while investigating ways to access the auxillary vector, I found that we
currently don't deal correctly with struct ps_strings in 32bit compat.
This structure is placed by the kernel into the initial stack and
referenced in userland by __ps_strings. It is used by setproctitle(3)
and therefore e.g. by programs that want to include a status report in
the ps(1) output. This naturally works only by chance, if at all in
compat32. How do we want to deal with it?

Variant 1: Leave it as broken. It should be said that having reliable
ps_strings could speed up ld.elf_so a bit.

Variant 2: Introduce two methods for obtaining and setting ps_strings of
a specific process and hook those into the normal exec mechanism. This
would in theory allow emulations pretty arbitrary data structures.

Other options that are better?

Joerg