"New" Idea: maybe belongs in programming forum...

Alright, I've got this idea that really only applies to laptops (I believe).

AND, in particular to laptops like my old Dell Inspiron 6400 with a battery that will power the machine for a few (like 5) minutes, at most.

(BTW, openSUSE 11.4 Xfce, not that it matters.)

In /etc/inittab there are the following lines:

pf::powerwait:/etc/init.d/powerfail start
pn::powerfailnow:/etc/init.d/powerfail now

I know these are there to allow UPS software to tell init to do a shutdown if and when the power fails. How does that work? What triggers these events?

What I'd like is for the pf: line to get kicked if the AC power fails, giving the machine time to shutdown gracefully.

Does anyone know how to write something that does that? Alternatively, of course, a script could just execute shutdown (provided it had enough privilege.) So, really, the question is, how do I find out if we're running on AC, or get a poke when that ceases to be the case?

What I'm envisioning is a bash/perl/python script or C program that runs as a daemon, gets the signal from APM or ACPI and either uses inittab or not to shut the machine down.

Any pointers would be greatly appreciated. Thanks!

Okay, having received no reply... and after a bit more research, here's what I tried:


$ cat /etc/acpi/events/battery
event=battery.*
action=/etc/acpi/actions/battery.sh


$ cat /etc/acpi/actions/battery.sh
#!/bin/bash
# ac/battery event handler
#
status=`awk '/^state: / { print $2 }' /proc/acpi/ac_adapter/AC/state`

if [ "$status" = "off-line" ]
then
## following line still contains -k option (just kidding...)
/sbin/shutdown -k now "AC Adapter Unplugged... Shutting system down now!!!!"
else
#
/sbin/shutdown -c now "AC Power Restored... System continues"
fi

and:
$ ls -l /etc/acpi/actions/battery.sh
-rwxr-xr-x 1 root root 626 Aug 16 17:43 /etc/acpi/actions/battery.sh

/var/log/messages shows acpid getting the correct number of rules.

I pull the plug and NOTHING HAPPENS.

I run the battery.sh script explicitly (as root) and it complains it can't find the pid of running shutdown (fair enough since there isn't one.)
I can also test the awk line on the cl and it works fine.

so: acpid isn't triggering the script.

How to debug?

Have you tried running the acpid daemon in the foreground, with the debug flag on?

Code:

---

service acpid stop
acpid -d -f

---

maybe that will turn up something.

That was a very useful reply, thank you!

I found that acpid -f -d -l was needed to get acpid to 'log' to STDERR. That showed me that the 'event' was not a battery event, but an 'ac_adapter' event.

So:

Code:

---

$ cat /etc/acpi/events/ac_adapter
event=ac_adapter.*
action=/etc/acpi/actions/ac_adapter.sh

---

and;

Code:

---

$ cat /etc/acpi/actions/ac_adapter.sh
#!/bin/bash
# ac/battery event handler
#                                                                                                                                 
status=`awk '/^state: / { print $2 }' /proc/acpi/ac_adapter/AC/state`
                                                                                                                                   
if [ "$status" = "off-line" ]
then
        /sbin/shutdown -h now "AC Adapter Unplugged... Shutting system down now!!!!"
else 
        /sbin/shutdown -c now "AC Power Restored... System continues"
fi

---

works beautifully!

Thanks again!
Daniel