script advice
Dear List,
I have a requirement for a maximum of one user logged in at any given time.
Following is a .profile script I wrote to enforce the requirement. The problem
is that when the script runs, sometimes the user trying to login is identified
as logged in and sometimes he/she is not identified as logged in. I.e., there
is a race condition between script execution and login completion. Any advice
for how to make it work properly? The brute force way is to loop on waiting
for the user to be logged in, as identified by the who command, and then check
the time of the login so as not to be confused if the user is already logged
in. Is there a better way? Thanks!
bash-2.04$ cat ./.profile
#!/usr/local/bin/bash
#
# Logout user if other user is logged in
#
shopt -s -o nounset
# Global Declarations
declare -rx SCRIPT=${0##*/}
declare USERS
#
# Logout User if Any Existing Users
$who
USERS=`$who | $wc -l`
printf %s existing users on this machine\n $USERS
if [ $USERS -gt 0 ] ; then
printf logging out\n
logout
fi
#
# End of Script
#
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Re: script advice
On 9/14/05, John Williams [EMAIL PROTECTED] wrote:
Dear List,
I have a requirement for a maximum of one user logged in at any given time.
Following is a .profile script I wrote to enforce the requirement. The
problem is that when the script runs, sometimes the user trying to login is
identified as logged in and sometimes he/she is not identified as logged in.
I.e., there is a race condition between script execution and login
completion. Any advice for how to make it work properly? The brute force
way is to loop on waiting for the user to be logged in, as identified by the
who command, and then check the time of the login so as not to be confused if
the user is already logged in. Is there a better way? Thanks!
Exclude the users own tty.
TTYDEV=`/usr/bin/tty`
TTY=`/usr/bin/basename $TTYDEV`
USERS=`/usr/bin/who | /usr/bin/grep -v $TTY`
[ -z $USERS ] {
echo Other users logged on!
echo $USERS
echo logging out...
logout
}
--
Noel Jones
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