[systemd-devel] how to end a socket activated daemon

[Zbigniew Jędrzejewski-Szmek]

On Tue, Jun 18, 2013 at 12:04:40PM +0200, Łukasz Stelmach wrote:
> It was <2013-06-17 pon 20:51>, when Lennart Poettering wrote:
> > On Fri, 14.06.13 14:33, Zbigniew Jędrzejewski-Szmek (zbyszek at in.waw.pl) wrote:
> >
> >> On Fri, Jun 14, 2013 at 10:03:00AM +0200, Łukasz Stelmach wrote:
> >>> We are converting some daemons to socket activation. Most of them
> >>> open unix sockets and manage incoming connections in a main-loop, so
> >>> the easiest way to convert it is to create Accept=false socket with
> >>> systemd.
> >>> 
> >>> Now, it is quite well described how to start such daemon, however,
> >>> there is little about shutting it down. Should the daemon close(2)
> >>> the received sockets? Should it unlink(2) them from a filesystem?
> >> close() yes, unlink() no.
> >
> > Strictly speaking you don't even have to do that. The kernel will
> > clean up left-over fds when your process exits, hence you don't have
> > to close it explicitly.
> >
> > But you certainly should not unlink() the socket in the fs, because
> > then the socket will not be accessible anymore.
> 
> Maybe I've asked the wrong question. I should rather have asked: Can I
> close? Can I unlink? Because that's what the code does now and we wanted
> to know which parts are common for standalone and
> systemd-socket-activated paths.
> 
> Thanks for the information.
> 
> PS. I think this information should be somewher in the docs. Do you
> think the paragraph describing Accept= in the systemd.socket.5 man page
> is the right place?
Yes.

Zbyszek