paul@vcvax1.UUCP (paul) (08/14/85)
The following is a shell-script called "ttystate",
which is used to enable and disable tty lines.
It is standardly provided with our VENIX System V system.
It works only on systems based on UNIX System V, as
it relies heavily on the System V "telinit" functionality.
A manual page is also provided.
To install, extract the lines following the cut-line below;
run the resulting file through /bin/sh. The result
will be a shell script called ttystate.sh, which should
be moved to /etc/ttystate, and a manual page called
ttystate.man.
Comments/enhancements are welcome.
Paul Kleppner
VenturCom, Inc.
{harvard,mit-eddie}!cybvax0!vcvax1!paul
----------------------------- CUT HERE -----------------------------
cat > ttystate.sh <<\END-OF-FILE
:
# @(#)ttystate.sh 2.1
#
# Courtesy of VenturCom, Inc.
# 215 First Street
# Cambridge, MA 02142
# 617/661-1230
#
# For UNIX System V-compatible systems only.
SPEED= FFLAG= KFLAG= MODE= ECOM1= ECOM2=
USAGE="Usage: ttystate [-edfk] [-s speed] line"
PATH=/bin:/etc:/usr/bin
fatal(){
echo "ttystate: $@" >&2
exit 1
}
set -- `getopt edfks: $* 2>&-`
if [ $? != 0 ]
then
echo "$USAGE" >&2
exit 1
fi
for ARG
do
case $ARG in
-e) MODE=on; shift ;;
-d) MODE=off; shift ;;
-s) SPEED=$2; shift 2 ;;
-f) FFLAG=yes; shift ;;
-k) KFLAG=yes; shift ;;
--) shift ; break ;;
esac
done
if [ ! "$1" -o $# != 1 ]
then
fatal "$USAGE"
fi
LINE=$1
case $LINE in
/dev/*) LINE=`basename $LINE` ;;
esac
if [ ! -c "/dev/$LINE" ]
then
fatal "no such tty (/dev/$LINE)"
fi
TTYFIND="getty.*$LINE[ ]" #requires that LINE be followed by space/tab
IENTRY=`grep "$TTYFIND" /etc/inittab`
if [ ! "$IENTRY" ]
then
fatal "tty name ($LINE) not in /etc/inittab"
fi
set -- `who -ul | grep "[A-z]* *$LINE"` ""
USER=$1
PID=$7
if [ ! "$MODE$SPEED" ]
then
case $USER in
"") echo "$LINE is off" ;;
LOGIN) echo "$LINE is active (waiting for login)" ;;
*) echo "$LINE is active ($USER logged in)" ;;
esac
exit 0
fi
if [ "$MODE" = "off" -a "$FFLAG" != yes -a "$USER" -a "$USER" != LOGIN ]
then
fatal "can't turn off $LINE: $USER logged in"
fi
IFS=":"
set -- $IENTRY
case "$MODE:$3" in
on:off) ECOM1="/$TTYFIND/s/:off:/:respawn:/" ;;
off:respawn) ECOM1="/$TTYFIND/s/:respawn:/:off:/" ;;
on:respawn) fatal "$LINE already enabled."; ;;
off:off) fatal "$LINE already disabled."; ;;
*) fatal "Illegal run state ($3) for $LINE in /etc/inittab"; ;;
esac
if [ "$SPEED" -a `grep -c "^$SPEED#" /etc/gettydefs` -eq 0 ]
then
fatal "speed label ($SPEED) not in /etc/gettydefs"
fi
if [ "$SPEED" ]
then
ECOM2="/$TTYFIND/s/\($TTYFIND *\)[A-Za-z0-9]*/\1$SPEED/"
else
ECOM2="ka"
fi
ed - /etc/inittab <<!
H
$ECOM1
$ECOM2
w
q
!
if [ $? != 0 ]
then
fatal "error editing /etc/inittab"
fi
if [ "$MODE" = off ]
then
chmod 666 /dev/$LINE
if [ "$KFLAG" -a "$PID" ]
then
kill -9 $PID
fi
fi
telinit q
END-OF-FILE
cat > ttystate.man <<\END-OF-FILE
TTYSTATE(1M) (Courtesy of VenturCom, Inc.) TTYSTATE(1M)
NAME
ttystate - turn on and off terminal login process
SYNOPSIS
/etc/ttystate [ -edfk ] [ [ -s speed ] ttyname
DESCRIPTION
ttystate enables and disables login processes on the named
tty. Lines with login processes on them may not be used for
dial-out purposes (e.g. by cu or uucp(1)), and vice versa,
so this command is useful for temporarily changing from one
use to another.
ttyname is the name of a device node in /dev. The name may
be given as either the full device name (e.g. ``/dev/com1")
or simply its last element (``com1'').
The flags available are:
-e Enable a login process on the device.
-d Disable a login process on the device. In addition,
the device mode is set to 666 (i.e., full read/write
access).
-sspeed
Sets the baud rate entry for the device to speed, e.g.
1200, 4800, or 9600. The given rate will be stored,
but will only become effective when the device is
changed from a disabled to enabled state. This will
not change the baud rate of a device that already has
an active login process. speed is any argument that is
valid as the speed to getty(1m).
-f When used with the -d flag, -f disables the device
login even if someone is currently logged in. If -f is
not given, ttystate refuses to disable a device that is
in active use.
-k After ttystate disables a login or user process on a
line, a grace period of approximately thirty seconds is
given before it is forcibly terminated. The -k flag in
conjunction with -d forces an immediate kill of the
process.
ttystate works by editing the /etc/inittab file and running
``telinit Q.'' An entry for the device must already exist in
/etc/inittab, set to ``off'' or ``respawn'' states.
ttystate takes any speed argument given it and uses it to
substitute the getty argument in the /etc/inittab entry.
Thus the speed must be an existing label in the
/etc/gettydefs table.
- 1 -
TTYSTATE(1M) (Courtesy of VenturCom, Inc.) TTYSTATE(1M)
EXAMPLES
Disable com1 for login use:
/etc/ttystate -d com1
Enable com1 for login use at 1200 baud:
/etc/ttystate -e -s 1200 com1
Report the current setting for com1 device:
/etc/ttystate com1
FILES
/etc/inittab
/etc/gettydefs
SEE ALSO
init(1m), getty(1m), inittab(4), gettydefs(4)
kill(1), ps(1), who(1)
BUGS
Won't prevent turning on a login process for a line that is
already in use for dial-out purposes.
- 2 -
END-OF-FILE