Bug#844178: Better systemd integration

[Andreas Metzler]

On 2016-11-13 Michael Biebl <biebl at debian.org> wrote:
> Package: exim4
> Version: 4.88~RC4-2
> Severity: normal

> Hi,

> having a native systemd service for exim4 would be great. The sysv init
> script does a *lot* of stuff though, so I don't know, how easily a
> systemd conversion is possible.

Hello,

I have thought about this, too, and stopped before really trying to
convert. Some thoughts:

* Currently one could choose between running exim as before (-bd or
  -bdf) or with socket-activation (-bw). The latter requires a
  separate queue-runner.
* IIRC most of the complexity of the init script was originally driven
  by the wish for being able to use mailscanner which required two
  separate exim processes. However I think with 4.88's new named-queue
  feature it should be possible to avoid the need for separate exim
  processes.

> As an intermediate step, you can at least help systemd along a little,
> and tell it, that the sysv init scrip starts a long running process.
> For that, the magic # pidfile comment exists. If that is set, systemd
> will set the proper type (Type=forking) and will correctly set the
> main pid, i.e. it will notice if the main process this.
[...]

There is a problem. The pidfile location can overriden in
/etc/default/exim4. Isn't it worse if the pidfile comment points to the
wrong file?

cu Andreas

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