Why is restart command unset in openresolv?

1

I am in the process of adding fix / feature to openresolv and I have encountered a potential problem with the way the package is configured, but I am unsure whether it is a bug or deliberate.

The following is the context in which I encountered the problem:

Namely I am adding a config flag to it which automatically adds private dns zones to the unbound config file it generates when used with i.e. NetworkManager. Without it users would still have to manually keep a list of private top level domains, which the related feature already in openresolv unbound_insecure is supposed to prevent.

During the process of reverse-engineering how openresolv is used in nixos I encountered an error in the package that occurs when the following is set:

networking.networkmanager.enable = true;
networking.resolvconf.extraConfig = ''
  private_interfaces="*"
  unbound_conf=/etc/unbound/resolvconf.conf
'';

unbound_conf is a feature of openresolv which makes it automatically create a file at the specified location containing a forward zone for local dns.
https://roy.marples.name/projects/openresolv/configuration/resolvers/unbound

Enabling this feature causes the following warning to appear in NetworkManager:

NetworkManager[214529]: <warn>  [1722794513.2615] dns-mgr: resolvconf failed with status 256
NetworkManager[214529]: <warn>  [1722794513.2616] dns-mgr: could not commit DNS changes: resolvconf failed with status 256

The reason for this is that, after writing the file, openresolv tries to restart unbound using a command given to it at build time.

Which brings us to the source of the problem:

In the package in nixpkgs the restart command is set to false.
This ends up as the literal string “false” when it is compiled into the package.
I am still experimenting with what I can set it to to make it work or at least not error.

However, this was deliberately set very early in NixOS’s development:

Unfortunately there isn’t much information on why this was unset.
So before I submit a PR I wanted to ask if there is a reason why this feature is disabled…?

2

What does RESTARTCMD do, please?

3

IMO it’s unlikely to get a “why” answered here, as that’s a 12 year old commit from someone who doesn’t work on nixpkgs anymore.
You’re better off just submitting a PR if you have a better solution (though, please do explain the issue and the reasoning for your fix method in the PR description). Or if you believe there’s an issue, and don’t feel prepared to make a PR, you can create a GH issue instead.

4

It is compiled into openresolv and should be the command that restarts services in the init system / service manager. Openresolv uses it to restart other daemons it integrates with, such as unbound, dnsmasq, BIND, pdnsd, PowerDns and so on.

5

I wanted to ask anyways before pinging a bunch of people on github.
It feels like something that could have a very trivial answer from people who spent more time with linux networking than I have, but maybe it is also just a quick-fix that was never supposed to persist for 12 years but no-one cared to change it for now.

I will submit a PR, however actually setting it to a correct value is proving to be quite difficult (which is probably why noone bothered to fix it until now) :sweat_smile: