Bug#889144: stricter PIDfile handling breaks several daemons

[Simon Kelley]

On 04/02/18 20:26, Sven Hartge wrote:

> Does dnsmasq need a PIDfile when running under systemd? Can't it just
> not double fork, stay in the foreground using a Type=simple systemd unit?
> 
> That way the whole problem could be avoided all together.
> 

Sending signals to the dnsmasq process cause it to take various actions,
so it's likely that there are scripts out there that do the equivalent of

kill -<somesignal> `cat /run/dnsmasq/dnsmasq.pid`

The double-fork code in dnsmasq is also quite careful about error
handling; for instance passing an error code back through a pipe from
the forked process to the original process, so that any failure gets
reflected in the return code when the original process exits. That's
relevant to Michael's point, I think.

Cheers,

Simon.