psu-targets

This software adds two new system targets to systemd: psu-adp.target and psu-bat.target

How it works:

It adds a new event to acpid, which will activate a script if there is a ACPI event dectect which involves an externel power adapter. The script checks if there is an active external power adapter by looking into all directories in /sys/class/power_supply which begin with an 'A'. If there is a file called 'online' in one of the directories which contains a '1', it starts psu-adp.target, otherwise it starts psu-bat.target. These targets won't be stopped until there is another event which changes the active target.

This behaviour should work on most systems, because usually the name of the power supply directory is something like 'ADP1' or 'AC'. If this isn't the case with your setup, you can change psu-targets.sh accordingly.

You can check the logs with # journalctl -u psu-targets.

Installtion

You can use # make install to install all necesarry files. You also need to restart acpid.servce and start psu-targets.service once if you want to use the software immediately.

Example:

[Unit]
Description=echo if on battery

[Service]
Type=oneshot
ExecStart=echo battery

[Install]
WantedBy=psu-bat.target