Extending sockcred

["Matthew Mondor" <mm_lists%pulsar-zone.net@localhost>]

Although the AF_LOCAL SCM_CREDS ancillary message passing is of great
help, I noticed that it does not pass the PID of the process sending
the message.  This would be useful in the case of for instance, a
syslogd-like daemon.

Although extending sockcred to add the PID would probably be trivial,
I'm wondering if it's a good idea (it would break binary ABI without
compat code, and is tricky because groups are of arbitrary size at the
end of the structure).  I guess that it also would be possible to
create a new SCM_PID or similar.

Anyone familiar with precedents for this, or with alternative
suggestion?  It appears that ancillary messages are largely
OS-specific in general.

Thanks,
-- 
Matthew Mondor