Subject: Re: increasing UT_HOSTSIZE for IPv6?
To: Christos Zoulas <christos@zoulas.com>
From: Dan Winship <danw@MIT.EDU>
List: tech-userlevel
Date: 07/23/1999 15:24:10 
Oh, you might have been confusing utmpd with update_utmp, which is a
setuid program Solaris uses so non-root programs can frob utmp{,x} in
limited ways. pututline() and pututxline() exec update_utmp if you
aren't running as root, but all update_utmp does is call pututline()
or pututxline() again after verifying the data.

-- Dan
the two files are kept in sync is that you're supposed to use the libc interfaces (pututline/pututxline) to write to them, and a call to either one will update both files. If you write to the files by hand, you have to update both of them, or they'll get out of sync, and then things that read utmp will think you're logged in and things that read utmpx won't, or vice versa. -- Dan