Section: User Commands (1)
Updated: sessreg 1.0.0
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sessreg - manage utmp/wtmp entries for non-init clients
Sessreg is a simple program for managing utmp/wtmp
entries for xdm sessions.
System V has a better interface to /etc/utmp than BSD; it
dynamically allocates entries in the file, instead of writing them at fixed
positions indexed by position in /etc/ttys.
To manage BSD-style utmp files, sessreg has two strategies. In
conjunction with xdm, the -x option counts the number of lines in /etc/ttys
and then adds to that the number of the line in the Xservers file which
specifies the display. The display name must be specified as the
"line-name" using the -l option. This sum is used as the "slot-number" in
/etc/utmp that this entry will be written at. In the more general case, the
-s option specifies the slot-number directly. If for some strange reason
your system uses a file other that /etc/ttys to manage init, the -t option
sessreg to look elsewhere for a count of terminal sessions.
Conversely, System V managers will not ever need to use these options (-x,
-s and -t). To make the program easier to document and explain,
sessreg accepts the BSD-specific flags in the System V
environment and ignores them.
BSD and Linux also have a host-name field in the utmp file which doesn't
exist in System V. This option is also ignored by the System V version of
In Xstartup, place a call like:
sessreg -a -l $DISPLAY -x /usr/X11R6/lib/xdm/Xservers $USER
and in Xreset:
sessreg -d -l $DISPLAY -x /usr/X11R6/lib/xdm/Xservers $USER
- -w wtmp-file
This specifies an alternate wtmp file, instead of /usr/adm/wtmp for BSD or
/etc/wtmp for sysV. The special name "none" disables writing records to
- -u utmp-file
This specifies an alternate utmp file, instead of "/etc/utmp". The special
name "none" disables writing records to /etc/utmp.
- -l line-name
This describes the "line" name of the entry. For terminal sessions,
this is the final pathname segment of the terminal device filename
(e.g. ttyd0). For X sessions, it should probably be the local display name
given to the users session (e.g. :0). If none is specified, the
terminal name will be determined with ttyname(3) and stripped of leading
- -h host-name
This is set for BSD hosts to indicate that the session was initiated from
a remote host. In typical xdm usage, this options is not used.
- -s slot-number
Each potential session has a unique slot number in BSD systems, most are
identified by the position of the line-name in the /etc/ttys file.
This option overrides the default position determined with ttyslot(3).
This option is inappropriate for use with xdm, the -x option is more useful.
- -x Xservers-file
As X sessions are one-per-display, and each display is entered in this file,
this options sets the slot-number to be the number of lines in
the ttys-file plus the index into this file that the line-name
- -t ttys-file
This specifies an alternate file which the -x option will use to count
the number of terminal sessions on a host.
This session should be added to utmp/wtmp.
This session should be deleted from utmp/wtmp. One of -a/-d must
Keith Packard, MIT X Consortium
- SEE ALSO
linux.jgfs.net manual pages