Path: utzoo!attcan!uunet!mcsun!hp4nl!star.cs.vu.nl!maart
From: maart@cs.vu.nl (Maarten Litmaath)
Newsgroups: comp.unix.questions
Subject: Re: Problem with getuid() -- same as geteuid()?!
Message-ID: <5339@star.cs.vu.nl>
Date: 7 Feb 90 23:49:08 GMT
References: <1836@clyde.concordia.ca> <?_3}%-@rpi.edu> <1837@clyde.concordia.ca> <5315@star.cs.vu.nl> <1844@clyde.concordia.ca>
Sender: news@cs.vu.nl
Reply-To: maart@cs.vu.nl (Maarten Litmaath)
Organization: VU Informatika, Amsterdam, the Netherlands
Lines: 42

In article <1844@clyde.concordia.ca>,
	smw@maxwell.Concordia.CA ( Steven Winikoff ) writes:
\...
\>		char	*getenv(), *lprname = getenv("LPRNAME");
\...
\>...where `my_lpr' is:
\>
\>	#!/bin/sh 
\>
\>	exec 3>&1

Dup(2) file descriptor 3 from 1.

\>	test -t 0 && exec < /dev/null

If stdin is a terminal, connect stdin to /dev/null.

\>	(/usr/ucb/lpr ${1+"$@"} | cat >&3) 2>&1 | cat >&2

Feed lpr's stdout to the first cat, whose stdout is dupped to the original
(saved) stdout; feed lpr's stderr to the second cat (mjum), whose droppings
go to the original stderr.  Now none of lpr's stdin/stdout/stderr points to
a terminal, so lpr will use getpwuid(getuid()), as getlogin() fails.
Piece of cake, right?

\I'm not quite sure I understand your code.  Who sets LPRNAME?  In "my_lpr",
\what gets exec'd in line 2?  Please excuse my ignorance, I'm only a wizard
\wanna-be!

Each user himself should set LPRNAME (.profile/.login) and change it
accordingly after a su (it's easy to write a wrapper for su which sets
LPRNAME beforehand).
You could use USER or LOGNAME, but beware: there are programs which expect
those to contain *login names* (e.g. inews). :-(

\...
\Love your .sig!

Thanks.
--
  The meek get the earth, Henry the moon, the rest of us have other plans.  |
  Maarten Litmaath @ VU Amsterdam:  maart@cs.vu.nl,  uunet!mcsun!botter!maart