Authenticating Unix Domain sockets.

[Peter Moore]

What I would like is a guaranteed way of finding out the uid of a process
that just connected to me using local (same machine) IPC.  I have vague memory
of special ioctl or connect argument that would give me the uid of the
connecting process when using Unix domain sockets.  But I have RTFM
(actually greped the man pages) and haven't found any sign of such a beast.

Normally I would have chalked this up to youthful hallucinations , but
I also didn't find the magic method to pass open file descriptors over
Unix domain sockets, and I KNOW that used to be in at least 4.3 BSD Unix.

So, does anyone know of such a beast?  Authentication of IPC of any
sort on almost any Unix would be of interest.
 

	Peter Moore
	Objectivity Inc.
	peter at objy.com