Move killpower flag file to /run

[bigon]

Hi,

Shouldn't the killpower flag file moved to /run (or /run/nut, or...) to avoid abusing /etc?

That would requires an upgrade path an maybe coordination with other to fix initscripts?

[jimklimov]

I am not sure what the reason was for the initial choice - possibly systems from long ago that did not have the likes of tmpfs, but did unmount "all" filesystems they could (so would've lost a /var/* location).

Probably makes sense to have this (dir or full dir/file pathname) a configure-customizable value (and likely defaulting to legacy /etc), with the rest being left to distro/packaging maintainers. It should be then used by both tools that set it (e.g. upsmon) and read/use it (e.g. init-scripts or systemd/smf/... methods).

Also note that many systems use /var/run (and those that mount really a /run tmpfs do also provide a /var/run symlink to it) so I guess it should be the safer "other default" choice.

[jimklimov]

Came back to this idea (thought it anew and found in history ;) happens...) and looked at the codebase. Indeed, killpower and POWERDOWNFLAG strings (and related C powerdownflag variable name) are only mentioned in clients/upsmon.c, docs, sample configs, augeas tools lenses, and init-scripts. In fact the filename should not be mentioned in the latter since upsmon -K should hide the internal detail and check for the flag in whatever arcane ways are possible.

I looked at upsmon.c and it only deals with configured setting from ups.conf and does not hardcode any path, and supports lack of it (checks for NULL before use). It also removes the file on any startup except when quick-checking for existence (upsmon -K).

For this issue, I think it should become a configure-time option to set the default (to bake into conf/upsmon.conf.sample) - probably keeping current value for least-surprise, with distros free to override for whatever FS they keep R/O mounted in the end. Probably using the PID directory would be a good choice for most systems, unless it is in a /var partition that gets unmounted :)

[jimklimov]

Followed up in #2383