Kent West <we...@acu.edu> writes:
> On Wed, Apr 26, 2017 at 4:52 PM, Kent West <we...@acu.edu> wrote:
> I've got 90% of it done, but I need it to logout after a certain
> time of inactivity, but only after the computer has been used at
> least once since the last start of X (otherwise it'll just be in a
> slow loop of restarting X).
>
> - boot into X
> - sit idly for 20 minutes, 2 hours, 3 days, whatever, screensaver
> running, until a guest comes up and uses the kiosk
Do you mean the display manager is running waiting for a user to log in,
possibly allowing a passwordless guest login? Upon login the display
manager executes an initialisation script, possibly .xinitrc. In this
script you can set up the kiosk session:
- start the program/script that will forcibly log the user out once
a certain time has passed.
- start a program/script to monitor the xscreensavers state
- start some basic programs (window manager, panels) so that a user
can actually do something
- whatever else you can think of
You may also want to consider that a user probably should not be able to
edit the initialisation script (xinitrc) or kill the program/script that
will exit the session automatically after a certain time has passed.
When using a display manager the FRESH_X variable might not be
necessary.
> In my .xinitrc, I have
>
> export FRESH_X=TRUE
>
> Then I want to have a script that sits and waits for a keypress or a
> mouse activity; this is where I need the syntax help.
When you refer to "script" do you mean a separate script file that you
call or simply more commands following the shells "export" command?
> When that script sees keyboard or mouse activity, it will export
> FRESH_X=FALSE
In case you are talking of a script file you run (instead of source [1])
be aware that the value of environment variables is not shared among
processes: a parent process can pass environment variables to a child
process on execution, but once the child exists both parent and child
have their own copy of the environment.
The "export" command only controls which of the shell's environment
variables are passed to the child: exported variables are passed to a
child on execution.
> But I need help with the syntax of checking for a keypress or mouse
> activity. I've looked at xinput and xev and another tool something
> like xenv, but I can't figure out the syntax in a bash if/then
> statement.
The following snipped can be used to block further script execution
until xinput reports an event. It reads lines from xinput until it
encounters a line starting with "EVENT" using, instead of the "if"
statement, the "case" statement [2] , which supports a simple form of
pattern matching.
xinput --test-xi2 --root | while read line
do
case $line in
EVENT*)
break
;;
esac
done
> I'll configure the xscreensaver-command --watch to watch for the
> screen saver to go BLANK, and when it does I check the status of
> FRESH_X ; if FRESH_X is FALSE, and the screensaver activates, I can
> set a 10-second time, check again to make sure the screensaver is
> still active, and then run my logout.
Searching the web, I found the xautolock [3] program. You may be able
to use its "-killer", "-killtime", "-locker", "-time" parameters to
realise your kiosk idea and save you some scripting.
Happy hacking. :)
Footnotes:
[1]
https://www.gnu.org/software/bash/manual/html_node/Bash-Builtins.html#index-source
[2]
https://www.gnu.org/software/bash/manual/html_node/Conditional-Constructs.html#index-case
[3] https://packages.debian.org/jessie/xautolock
--
Felix Dietrich
