script question

[Madanagopalan S]

1. Writing script to cancel print jobs. This script will cancel all the users print jobs.
this will be executed by the particular user. Can Anyone through how can I
achieve this. I tried suid option (chmod 4711 file). still have problem?

2. While running a script, user could not able to use ctrl+c or any other command
to get unix prompt. If any interruption occurs, it should go back to previous menu.

Pls help me.

[Andreas Voss]

Hi,

when using suid/sgid on shell scripts you must have at the first line (example posix-shell):
#!/sbin/sh
To prevent exiting the script by CTRL-C do:
trap "echo break" 2
(make sure you have an input option to leave the script)

Regards

[Madanagopalan S]

I tried the same. but its still saying " must have root capability to use this option" for cancel command. How can I do it for C program.

[James R. Ferguson]

Hi:

One way to avoid the suid problem altogether in this case is to (re)create your print queues allowing CANCEL by anyone. There's a check-box when you setup printers in SAM to specify this. The -orc option of 'lpadmin' controls this ability.

...JRF...

[Madanagopalan S]

I can't recreate the print queues since nearly more than 20 queues are there
and the machine is in production now.

[Andreas Voss]

Hi,

here an example c source:
main(argc, argv)
int argc;
char **argv;
{
setuid(9);
setgid(7);
execvp("/usr/bin/cancel", argv);
}
Compile ie:
cc mycancel.c -o /usr/contrib/bin/mycancel
chown lp:lp /usr/contrib/bin/mycancel
chmod ug+s /usr/contrib/bin/mycancel

Regards

[Madanagopalan S]

Andreas voss,

I can't able to use the '-e' option. other thing is working fine. What could
be the problem

[Andreas Voss]

Hi,

so you have to set root capabilties (but i think this could be a security risk):
main(argc, argv)
int argc;
char **argv;
{
setuid(0); setgid(3);
execvp("/usr/bin/cancel", argv);
}
Compile ie:
cc mycancel.c -o /usr/contrib/bin/mycancel
chown root:sys /usr/contrib/bin/mycancel
chmod ug+s /usr/contrib/bin/mycancel

Regards

[Alan Riggs]

Am I missing something? Isn't this exactly what the command "cancel -a" is designed to do? A user always has the ability to cancel his own print jobs, and teh -a flag tells cancel to stop all jobs to any printer owned by the login user.

[Carlos Fernandez Riera]

If -orc option run sucesfully to you, reacreate printers is not a great problem.

Fisrt, do a tar cvf /tmp/printers /etc/lp/interface

Write a script to remove and recreate printers based on lpstat -v ( printer and device ), for each printer you must generate commands:

lpadmin -x.....
lpadmin -d xxxxx -mdumb printer
enable printer
accept printer


As final step recover printer interfaces ( tar xvf /tmp/printers). Interface files are scripts, so dumb printer will be recover with actual script.

Create a printer for test, and when you procedure run ok, apply to all printers.




CNTRL-C.


If you dont like users break your shell do:
trap ' ' 2.
This will avoid treatement of INTR signal.