[gdm-list] Help How to kill instance of ext process launched from gdm

[Francesco Fumanti <francesco fumanti gmx net>]

Hello,



I know how to start an external onscreen keyboard by using the 
dwelling feature of the accessibility in onboard; and it works. (I am 
starting an onscreen keyboard named onboard, that is shipped by 
default with the Ubuntu-distribution; I am not talking about gok 
here, though I don't think it would make a difference for my problem.)

However I would also like to be able to quit the onscreen keyboard. 
So instead of making the dwell feature call the onscreen keyboard, it 
calls a script that does the following each time it is called:
- if the onscreen keyboard is not running yet, it starts it and 
places the pid of the onscreen keyboard in a file in /tmp
- if it is already running it kills the onscreen keyboard by using 
the pid stored in the pid file created when the onscreen keyboard was 
started; then it removes the pid file

Based on the existence of the pid file, the script can check whether 
the onscreen keyboard is already running and what instance to kill. 
This is working all working well on my single user computer.



Now to the problem:

It also has to work on computers with multiple users. But the file 
with the pid does not differentiate from what gdm-session it was 
created. Consequently, if two users at two different gdm-sessions 
start onboard, there will be the problem that the two instances of 
the script will check for the same pid file.

Could anybody please tell me how I can make a pid file specific for 
each session?

Maybe there is a better way than using a pid file in order to make 
each gdm-session know the pid of the instance of the onscreen 
keyboard started in it.



Many thanks in advance.

Francesco