使用ksh默认shell将shell函数导出为su作为用户

Question

I have a situation where only root can mailx, and only ops can restart the process. I want to make an automated script that both restarts the process and sends an email about doing so.

When I try this using a function the function is "not found".

I had something like:

#!/usr/bin/bash

function restartprocess {
/usr/bin/processcontrol.sh start
}

export -f restartprocess

su - ops -c "restartprocess"

mailx -s "process restarted" myemail.mydomain.com < emailmessage.txt

exit 0

It told me that the function was not found. After some troubleshooting, it turned out that the ops user's default shell is ksh.

I tried changing the script to run in ksh, and changing "export -f" to "typeset -xf", and still the function was not found. Like: ksh: exportfunction not found

I finally gave up and just called the script (that was in the function directly) and that worked. It was like:

su - ops -c "/usr/bin/processcontrol.sh start"

(This is all of course a simplification of the real script).

Given that user ops has default shell is ksh and I can't change that or modify sudoers, is there a way to export a function such that I can su as ops (and I need to run ops's profile) and execute that function?

I made sure ops user had permission to the directory of the script I wanted it to execute, and permission to run that script.

Any education about this would be appreciated!

Answer 1

There are many restrictions for exporting functions, especially combined with su - ... with different accounts and different shells.

Instead, turn your script inside out and put all of the command that is to be run inside a function in the calling shell.

Something like: (Both bash and ksh)

#!/usr/bin/bash

function restartprocess {
    /bin/su - ops -c "/usr/bin/processcontrol.sh start"
}

if restartprocess; then
    mailx -s "process restarted" \
        myemail@mydomain.com < emailmessage.txt
fi

exit 0    

This will hide all of the /bin/su processing inside the restartprocess function, and can be expanded at will.