On Tue, Sep 8, 2020 at 5:41 PM Lennart Poettering <lenn...@poettering.net> wrote: > > On Di, 08.09.20 17:35, Francis Moreau (francis.m...@gmail.com) wrote: > > > On Mon, Sep 7, 2020 at 4:38 PM Lennart Poettering > > <lenn...@poettering.net> wrote: > > > > > > "React on the socket close?" — What do you mean by that? > > > > > > > I mean if my service explicitly calls close() then systemd could stop > > the socket on its side so its are freed until the service is > > restarted. I think it is what you described below. > > close() just drops a ref to the socket. Only when close() drops the > last ref something actually happens on the socket and it is > destroyed. This means: systemd doesn't get notified about your code > invoking close(), because all you did is drop one ref of many. > > > > Note that on Linux you can invoke shutdown() on a listening socket > > > (i.e. not just on the connection socket, but on a listening > > > socket). iirc in that case systemd actually notices and will put the > > > .socket unit in failure mode... > > > > > > > I looked at the code and there is: > > > > if (state != SOCKET_LISTENING) > > socket_unwatch_fds(s); > > > > So I'm not sure how systemd can react on shutdown(). And I tried to > > call shutdown() in my service but it has no effects. > > Hmm, that suggests we'd have to slightly update our logic then for > this to work: keep the listening fds in the poll, but turn off all > the EPOLLIN bit we listen on. > > > > Would that work for you? (Maybe we could even tweak this a bit in > > > systemd, so that when you invoke shutdown() on the socket systemd > > > holds for you we do not consider that a failure anymore, but a clean > > > way to tell systemd to stop the socket). > > > > That is a good idea especially if systemd doesn't consider an error > > when the service closes or shutdown the socket. > > > > But again in the code I can see: > > > > sd_event_add_io(UNIT(s)->manager->event, &p->event_source, p->fd, > > EPOLLIN, socket_dispatch_io, p); > > > > It seems that it only listens to "EPOLLIN" events. So it doesn't > > listen to "EPOLLUP". > > EPOLLHUP is always implied, you don't have to specify it. if you > specifiy zero as mask you will still get notified about EPOLLHUP + > EPOLLERR. >
Thank you for the info > But you are right we currently remove the fd from polling while the > socket's service is running. We'd have to change that (as mentioned > above). happy to review a PR for that. I'm afraid I'm not skilled enough in systemd internals to work on this, sorry. _______________________________________________ systemd-devel mailing list systemd-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/systemd-devel
