Re: Re: Perfect Jessie is something like this...
Christian Seiler:
Finally: Upstart also supports socket activation. It's not quite as
> powerful as systemd's, but is has enough features for this use case.
> I don't know the people developing util-linux, but I could imagine
> them accepting a patch to also support Upstart-style socket
> activation, if one were to write such a patch.
>
> Or, if you want to: a while back I wrote some code to translate init
> system related stuff between one another. [...]
.. but in doing so you made the oft-made mistake of thinking that there
are only two service management systems. Although you did use the
slightly unusual variant of thinking that the only two were upstart and
systemd. (-: There are actually a lot more service management systems
than that, and have been for over a decade and a half. Some of them
also support running a socket-using process as a service, with the
service management system dealing with the mechanics of creating,
binding, listening, and accepting connections on the socket. See
http://homepage.ntlworld.com./jonathan.deboynepollard/FGA/run-scripts-and-service-units-side-by-side.html
for a side-by-side look at one family of such service management systems.
A run script for uuidd, which would work under daemontools,
daemontools-encore, freedt, runit, s6, and the nosh package, using the
nosh program as the script interpreter, would look something like:
#!/bin/nosh
setuidgid uuidd # Do this first, for the security reasons given
in local-stream-socket-listen(1) .
local-stream-socket-listen --systemd-compatibility /run/uuidd/request
uuidd --socket-activation
The service and socket units in util-linux likewise leave the creation
of the directory to something else. But perp, daemontools-encore, and
nosh have the capability of running "start" programs. In perp's case it
would be in the same, rather differently structured to all of the
others, rc.main script as the main daemon. nosh and daemontools-encore
use a separate "start" script, where one would perhaps put something like:
#!/bin/sh -e
mkdir -m 0755 /run/uuidd
chown uuidd:uuidd /run/uuidd/
nosh, runit, daemontools, and ucspi-unix can even be installed from
pre-built binary Debian packages. s6 binary packaging is awaiting
someone to roll up xyr sleeves at Debian #733915. (s6-networking has no
binary package that I know of, but I haven't checked thoroughly.
Neither have ipsvd or daemontools-encore. One can build them ALL from
source, of course.) As noted in the aforementioned side-by-side
comparison where it discusses exim: ucspi-unix and s6-networking don't
handle listen-only, which is unfortunate for daemons like this one which
don't do listen+accept. But as also pointed out in the side-by-side
comparison, albeit perhaps not prominently enough, the toolsets can be
mixed and matched.
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