access(2) (was: Writing to A NON-Existing File in "C")

[Richard A. O'Keefe]

In article <2001 at rtech.UUCP>, jas at llama.rtech.UUCP (Jim Shankland) writes:
> In article <975 at unmvax.unm.edu> mike at turing.UNM.EDU.UUCP (Michael I. Bushnell) writes:
> >There is another way [a program] can run under suid conditions: ...
> >% su
> >Note that nifty program will now have REAL uid foo and EFFECTIVE uid root.
 
> Nope.  This seems to be a common misconception.  su alters your
> real uid as well as your effective uid.

Nope, it's not a misconception.  Them's the facts.  Tried it just now:
% su
Password:
# wmi
root daemon     ok quintus

The SVID says "su will execute a new environment with the real and
effective user ID set to that of the specified user", though it remains
completely quiet about the group id.  However, not all UNIX systems are
System V.  Anyone know which variants do what?