Hi Jim, Everyone,
I had an earlier query regarding Derek Dresser's utmp logging solution and some
problems i had with it using
'who' and 'last'.
I'm sharing with you here some of my findings and modifications to Derek's scripts so
that 'who' and 'last'
works as it should ;-)
Jim, sorry if you receive this twice already. My mails here sometimes get clobbered.
Cheers,
Phil
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
'Instantaneous' UTMP Logging for LTSP Workstations
(modifications from Derek Dresser's utmp scripts)
Philip A. Roa
Intelisoft Microcomputer Systems
March 7, 2002
Purpose: To monitor currently connected LTSP thin clients on an LTSP server.
Problem: LTSP thin clients are not correctly reported by 'who' and 'last'
Disclaimer: I cannot be responsible for anything that happens to your system. Use at
your own risk. If you're not comfortable doing this, then i suggest you
have
someone qualified do stuff. You have been warned.
The source of the problem:
=========================
Sessions are appended to the utmp / wtmp logs via file:/usr/X11R6/bin/sessreg. From
the manual page of
sessreg, the -l (line-name option) option determines the record name of the utmp
entry. That is, a session
name is looked-up (or deleted in the future) via its line-name.This creates no
problems for terminal devices
since the final pathname segment of the terminal device filename accessing the server
is unique (e.g. ttyd0).
On the other hand, for X terminal sessions, the line-name normalizes to the host's
local display number
(usually the default ':0'). That is if you specify your line-name option as the
$DISPLAY, utmp only gets the ':0' -
a non-unique name. This is where our problem begins. When multiple clients (remote
thin clients) starts
accessing the LTSP server, it is only the last connected host that will be reported as
'still logged in'. The rest
of the current record entries get 'stepped-on' and purged from utmp (we don't want
that to happen).
The solution:
=============
To 'get-around' with this problem, we have to make 'line-name' unique. One way of
doing this is by extracting
the hostname component of the $DISPLAY variable (which is initially setup for us by
LTSP). This way, all our
connected LTSP thin clients will be correctly logged into utmp so our 'who' and 'last'
will work as it should.
Scripts:
========
There are 3 script files used here: sessreg.h, GiveConsole, & TakeConsole (on some
distributions you may
have Xstartup and Xreset scripts respectively).
Don't forget to set file permissions for all the 3 scripts to 755 (i.e. chmod 755
/etc/X11/xdm/sessreg.h...do..same..thing..to..the..rest..of..the..scripts...) when
you're done editing.
===============================================
file:/etc/X11/xdm/sessreg.h
---------------------------
Purpose: Prepares the line-name (-l),
and hostname (-h) options for sessreg
$LINENAME - contains the host portion of
$DISPLAY for our remote hosts.
Howerver, it resolves to
$HOSTNAME if the access is
done on the LTSP server itself
$LTSNAME - contains the hostname of the LTSP
server
===============================================
# to be used by GiveConsole and TakeConsole
LINENAME=`echo $DISPLAY | awk '{print substr($1,1,length($1)-2)}'`
if [ -z $LINENAME ]
then
LINENAME=$HOSTNAME
fi
LTSHOST="LTSP("$HOSTNAME":0)"
==========================================
file:/etc/X11/xdm/GiveConsole
-----------------------------
Purpose: Logs the start of an X session
The original file shown here
comes from Mandrake 7.0 (Air)
distribution. Modifications
are indicated.
==========================================
#!/bin/sh
# Assign ownership of the console to the invoking user
# $XConsortium: GiveConsole,v 1.2 93/09/28 14:29:20 gildea Exp $
#
# By convention, both xconsole and xterm -C check that the
# console is owned by the invoking user and is readable before attaching
# the console output. This way a random user can invoke xterm -C without
# causing serious grief.
#
chown $USER /dev/console
# Original line from distribution / commented out
#/usr/X11R6/bin/sessreg -a -w "/var/log/wtmp" -u "/var/run/utmp" \
# -x "/etc/X11/xdm/Xservers" -l $DISPLAY -h "" $USER
# Modified / PAR 02/02 to accomodate instantaneous utmp logging
source '/etc/X11/xdm/sessreg.h'
/usr/X11R6/bin/sessreg -a -w "/var/log/wtmp" -u "/var/run/utmp" \
-x "/etc/X11/xdm/Xservers" -l $LINENAME -h $LTSHOST $USER
==========================================
file:/etc/X11/xdm/TakeConsole
-----------------------------
Purpose: Releases an X session
The original file shown here
comes from Mandrake 7.0 (Air)
distribution. Modifications
are indicated.
==========================================
#!/bin/sh
# Reassign ownership of the console to root, this should disallow
# assignment of console output to any random users's xterm
# $XConsortium: TakeConsole,v 1.2 93/09/28 14:30:29 gildea Exp $
#
chmod 622 /dev/console
chown root /dev/console
# Original line from distribution / commented out
#/usr/X11R6/bin/sessreg -d -w "/var/log/wtmp" -u "/var/run/utmp" \
# -x "/etc/X11/xdm/Xservers" -l $DISPLAY -h "" $USER
# Modified / PAR 02/02 to accomodate hostname
source /etc/X11/xdm/sessreg.h
/usr/X11R6/bin/sessreg -d -w "/var/log/wtmp" -u "/var/run/utmp" \
-x "/etc/X11/xdm/Xservers" -l $LINENAME -h $LTSHOST $USER
# Scripts that you might want to run on exit (for housekeeping purposes) follows
#/usr/bin/umountncp-vol 2&> /dev/null
==========================
Output of 'who' and 'last':
==========================
------------------------------
bash# who -H
USER LINE LOGIN-TIME FROM
root admin1 Mar 7 11:23
abeng sales3 Mar 7 09:14
------------------------------
Note: 'admin1' and 'sales3' under the 2nd column (LINE) are our
LTSP thin clients (hostnames from $DISPLAY)
-------------------------------------------------------------------------
bash# last | head -n13
root admin1 LTSP(lts1:0) Thu Mar 7 11:23 still logged in
root admin1 LTSP(lts1:0) Thu Mar 7 10:40 - 11:23 (00:43)
amy acct1 LTSP(lts1:0) Thu Mar 7 10:39 - 10:42 (00:02)
abeng sales3 LTSP(lts1:0) Thu Mar 7 09:14 still logged in
abeng sales3 LTSP(lts1:0) Thu Mar 7 09:12 - 09:13 (00:01)
joey sales3 LTSP(lts1:0) Thu Mar 7 09:11 - 09:12 (00:00)
root lts1 LTSP(lts1:0) Thu Mar 7 09:09 - 09:21 (00:12)
proa admin1 LTSP(lts1:0) Thu Mar 7 09:11 - 09:36 (00:25)
proa admin1 LTSP(lts1:0) Thu Mar 7 09:09 - 09:11 (00:01)
reboot system boot 2.2.14-15mdk Wed Jan 23 13:52 (00:35)
proa pts/0 192.168.1.32 Wed Jan 23 11:28 - 11:32 (00:04)
proa ftp 192.168.1.32 Wed Jan 23 11:27 - 11:27 (00:00)
root pts/0 Wed Jan 23 11:23 - 11:23 (00:00)
reboot system boot 2.2.14-15mdk Wed Jan 23 10:29 (03:58)
-------------------------------------------------------------------------
Note: Entries with 'LTSP({hostname:0)' (3rd column) are log entries from
our scripts. Other entries were added to distinguish them from ours
;-). Entries #1 and #4 (from the top) are still currently still
connected.
Entry #7 shows an X Session done on the server itself (lts1)
Cheers!,
Phil
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