Prevent "pihole disable $timeout" from messing up future state changes

[tlk]

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---

What does this PR aim to accomplish?:
Fixes #2879
Prevent "pihole disable $timeout" from messing up future state changes.

Example:

pihole disable 30s
pihole enable
pihole disable
sleep 30
pihole status

Without this fix the following command sequence produces a somewhat surprising result, namely that pihole ends up being enabled. This is because pihole was enabled by a "reenable" job 30s after the first "disable" command. The operator, however, did not expect this because the last command to pihole was to disable itself.

With this fix the above command sequence will leave pihole disabled.

Please note that this fix depends on the existence of the pkill command.

I can confirm that pkill exists on my device running Raspbian GNU/Linux 10 (buster).

[DL6ER]

pkill is contained in procps. This package is often not available in minimal environments. It might even be missing in the official Pi-hole docker container (@diginc would know more).

If we decide to use pkill, we would - at least - have to add procps to the installer dependencies (see automated install/basic-install.sh).

[diginc]

procps is already part of the docker deps: https://github.com/pi-hole/docker-pi-hole/blob/4eb10fd63af493d81226209823aa3950c9b282d1/install.sh#L17

[tlk]

Thank you for checking up on pkill. After diving into a couple of rabbit holes over at #2879 I have updated the PR, and it no longer depends on pkill but uses a combination of killall and a new wrapper script.

The new wrapper script does not have the .sh suffix. This is because the name of the wrapper script is limited to 15 characters for it to be targetable by killall and the pihole-reenable name is exactly 15 characters. Please share if you know how to convince killall to target scripts with longer filenames.

[dschaper]

Since the file will be in /opt/pihole you don't really need to call it pihole-reenable. reenable.sh will work fine.

[oakkitten]

yes, but killall reenable might kill unwanted stuff

anyways, the process name of pihole-reenable.sh is pihole-reenable 🙄 so it will work

$ ./pihole-reenable.sh & cat "/proc/${!}/stat"
[3] 3927
3927 (pihole-reenable) R 1534 3927 1534 34825 392 ...

I tried testing this branch but i have no idea how to install pihole from git. any hints?

[tlk]

yes, but killall reenable might kill unwanted stuff
anyways, the process name of pihole-reenable.sh is pihole-reenable 🙄 so it will work

Good point! Renamed to pihole-reenable.sh

[PromoFaux]

I tried testing this branch but i have no idea how to install pihole from git. any hints?

@oakkitten :

git clone https://github.com/pi-hole/pi-hole /etc/.pihole
cd /etc/.pihole
git checkout [whatever branch here]
./automated\ install/basic-install.sh

though if you wanted to try this branch specifically, then do this after moving into the directory:

git checkout -b tlk-fix/reenable development
git pull https://github.com/tlk/pi-hole.git fix/reenable

@DL6ER , do your change requests still stand?

pkill is no longer used

[PromoFaux]

@tlk Please could you resolve the merge conflicts on PR, thanks!

[tlk]

@PromoFaux Sure. Just checking - is pi-hole:development the correct target branch?

[PromoFaux]

Yep! All new code goes into development before master

[HighMileage]

@tlk it looks like this PR has been waiting for a rebase for almost 6 months. Do you have time for this rebase or would you rather someone else open a PR and drive this work?

[tlk]

@HighMileage Thank you for the kind reminder!

@PromoFaux The PR has now been rebased to development and this should solve the merge conflicts.

[HighMileage]

@PromoFaux can you take a look at this PR 👀? It's been rebased and should be good to merge now

[pralor-bot]

This pull request has been mentioned on Pi-hole Userspace. There might be relevant details there:

https://discourse.pi-hole.net/t/pi-hole-5-1-released/35577/1