Path: utzoo!attcan!uunet!munnari.oz.au!goanna!ok
From: ok@goanna.cs.rmit.oz.au (Richard A. O'Keefe)
Newsgroups: comp.lang.c
Subject: Re: Complexity of reallocating storage (was users command crap)
Message-ID: <4690@goanna.cs.rmit.oz.au>
Date: 1 Feb 91 08:50:47 GMT
References: <22870@well.sf.ca.us> <22311:Jan2502:34:1191@kramden.acf.nyu.edu> <19010@rpp386.cactus.org>
Organization: Comp Sci, RMIT, Melbourne, Australia
Lines: 15

In article <19010@rpp386.cactus.org>, jfh@rpp386.cactus.org (John F Haugh II) writes:
> 	fd = open ("/etc/utmp", O_RDONLY);
> 	fstat (fd, &statb);
> 	users = (struct utmp *) malloc (statb.st_size);
> 	read (fd, (char *) users, statb.st_size);

That's what I used.  /etc/utmp appears to be a fixed size file anyway,
and the number of slots in that file doesn't seem to bear any obvious
relation to the number of entries in /etc/ttys (other than being bigger).
But I've been wondering whether a super-user editing /etc/ttys and then
sending SIGHUP to 'init' might break this and what would be the best way
to tell.  If it was my own file, I could use locks.
-- 
The Marxists have merely _interpreted_ Marxism in various ways;
the point, however, is to _change_ it.		-- R. Hochhuth.