[Pkg-dns-devel] Bug#867192: Bug#867192: Bug#867192: Bug#867192: Bug#867192: Bug#867192: Bug#867192: let systemd know about the pid file

[Daniel Kahn Gillmor]

On Fri 2017-07-14 16:25:26 -0400, Robert Edmonds wrote:
> Well, we would append the "-p /run/unbound.pid" bit to DAEMON_OPTS in
> the sysvinit script unconditionally, something like:
>
>     [...]
>     # Override this variable by editing or creating /etc/default/unbound.
>     DAEMON_OPTS=""
>
>     if [ -f /etc/default/unbound ]; then
>         . /etc/default/unbound
>     fi
>
>     DAEMON_OPTS="$DAEMON_OPTS -p $PIDFILE"
>     [...]
>
> No changes to the interface/contract. In fact this seems less broken to
> me, because we hardcode the path to the pidfile in the sysvinit script.
> Currently, if you set 'pidfile' yourself to some other value in the
> Unbound config then start-stop-daemon looks in the wrong place for the
> pidfile.

I understand what you're saying from the point of view of debian, though
it still makes it a little bit strange because then anyone who manually
puts DAEMON_OPTS="-p /foo/bar" in /etc/default/unbound has it get
overridden.

But i was thinking about the issue from upstream -- they have to
coordinate their daemon changes with everyone using unbound, and the
semantics of running "unbound -c foo.conf" will now change if we change
the default, since the default path for the pidfile itself is currently
compiled in (if you don't specify pidfile in the config file it'll still
create a pidfile, i think).

One way to make your approach more feasible (without changing upstream's
expected contracts generically) would be to something like (untested):

    ./configure --with-pidfile=

(that is, the empty pidfile).  Then anyone on a debian system without a
pidfile directive in the .conf just wouldn't get a pidfile (since
daemon/unbound.c tests pidfile[0]).  if we did that, then adding your
proposed implementation to the init script would make sense -- because
there'd be no public expectation that -p is something you'd manually
supply in DAEMON_OPTS.  I guess we're saying that "-p /foo/bar" should
take precedence over 'pidfile: "/baz/qux"' in the config file, right?

         --dkg