NetNews Usenet Archive 1993 #3/NN_1993_3.iso/spool/comp/unix/xenix/sco/3747

Text File | 1993-01-28 | 1.7 KB | 42 lines

Newsgroups: comp.unix.xenix.sco
Path: sparky!uunet!ukma!asuvax!cs.utexas.edu!torn!newshub.ccs.yorku.ca!newshub.ariel.yorku.ca!cs911077
From: [e-mail] (Iain Calder)
Subject: Q: wtmp file format
Message-ID: <[e-mail]>
Summary: Is the login-name field 8 or 7-character?
Sender: [e-mail] (USENET News System)
Organization: York University, Toronto, Canada
Distribution: na
Date: Thu, 28 Jan 1993 19:33:36 GMT
Lines: 29

[ The first posting apparently >/dev/null.
  Apologies if you've seen this twice. ]

Well, I looked and looked and looked in the manual and found nothing
so I turn to the net were the wise people live :-).

/etc/wtmp is a log of logins. For each login, it reserves 8 bytes
to store the login-name. The login-name is padded on the right with
NULs to fill the 8 bytes.

But this field could also be seen as *7* bytes for the name followed
by a NUL, thus being a NUL-terminated string.

Which of the two is it?

For one thing, in xenix 2.3.1, `last username' doesn't work for
8-character names: it searches until it reaches the end of the file
but doesn't report the searched-for 8-character name. On the other hand,
`last' without parameters correctly reports *all* logins including
8-character ones. I wonder if this is a bug which was later fixed or
if wtmp is designed for 7-byte names max.

Please e-mail; I'll summarise.
--
Location: Toronto, Ontario, Canada        Name: Iain Calder
internet: [e-mail]   Messalina Public Access Xenix:
 fidonet: Iain Calder @ 1:250/318    [phone] (2400bps 8N1)
  bitnet: yusol::cs101204                 type `newuser'
    uucp: ...!mail.uunet.ca!r-node.gts.org!messalina!{iain,root}