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Login Running a Captive Shell Script

I have written a shell script (ksh) that allows a user to use a menu selection to nfs mount remote partitions.  I want this shell script to automatically launch when the user logs into a dedicated login, run without the user being able to exit it <ctl c>, and log out when the user selects <exit> from the menu selections.  The login account will have sudoer permission to mount/unmount only.

Should the shell be launched from the .profile?
What needs to be in the shell to prevent a <ctl c>, etc, exit?
Special permissions on the script or the .profile?
Any "how-tos" in case I'm forgetting (to ask) something?

Tips/Comments/Suggestions appreciated!
Thanks.
0
dskhunter
Asked:
dskhunter
4 Solutions
 
stefan73Commented:
Hi dskhunter,
You can trap signals and error conditions in ksh:

trap exit INT TERM HUP TSTP ERR

this will invoke exit for both CTRL-c and CTRL-z, errors, kill, etc.

See "man -s 3HEAD signal" for a list of all signals.



Cheers,
Stefan
0
 
tfewsterCommented:
The simple, but not foolproof way: At the end of the .profile add the lines:

trap 'echo "Ctrl-C disabled" ' 1 2 3 15
/path/to/menu_script
exit


However, it may be possible for them to ^C out while the .profile is executing, before the trap, so either make the "trap" statement 1st thing in the .profile or alternatively:

Amend their login shell in /etc/passed to be "/path/to/menu_script";  You may need to add this to /etc/shells;  Put the trap and  exit statements in the menu script
0
 
stefan73Commented:
dskhunter,
Just make sure that the login shell exits as soon as your shell script is finished. You could use .profile for the shell script. Also check that the trap command is the first you call.


Stefan
0
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durindilCommented:
The best way to do this is set up an RBAC role, and a profile shell.  Trap the CTL-C inputs, and even if they can break out, they are still in the profile shell, and only have the permissions you assign to them.
0
 
OtetelisanuCommented:
With the trap is OK but
you can start your programm
with
exec <program>

look man exec

0
 
OtetelisanuCommented:
Sory
the exec <program> must be
in the .profile

0
 
ahoffmannCommented:
write your shell like follows:

#!/bin/ksh
trap myexit 1 2 3 4 5 6 7 8 10 11 12 13 14 15
function myexit
{
  exit 1
}
# your stuff here
exit 0

then simply use this script in /etc/passwd as login shell
I'd never use .profile or alike for this
0

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