rcrun(8), service(8) and future directions

[Samuel J. Greear]

A discussion along these lines occurred recently on the DragonFly BSD
developer IRC channel on EFNet, #dragonflybsd. The consensus was that the
service command could go, and that rcrun could use some improvements, the
service interface need not necessarily be maintained if rcrun can do all of
the same things.

You should pop into the IRC channel and continue this discussion, as well
as taking into account any other input on this email list.

Sam

On Mon, Nov 17, 2014 at 3:11 PM, Robin Hahling <
robin.hahling at gw-computing.net> wrote:

> service(8) was brought in past summer, from FreeBSD, as a way to control
> system
> services, as an interface to rc.d system. Since version 1.0 (December 2003
> to
> be exact), DragonFly has had rcrun(8) while service(8) was added to
> FreeBSD in
> December 2009.
>
> Having service(8) in DragonFly allow users or sysadmins to find their way
> around the system a but more quickly since service and its syntax is used
> in
> popular systems such as FreeBSD or even Red Hat and other distributions in
> the
> linux world. However, it would make sense to have service(8) implemented
> as a
> wrapper around rcrun(8) and not a program in itself for obvious reasons. I
> volunteer for the task if people agree with this idea but really, it
> should be
> a no brainer.
>
> While on the subject, rcrun(8) syntax needs to evolve in order to be able
> to
> pass arguments to rc scripts. Future bluetooth rc scripts will need it for
> instance. The current rcrun(8) syntax is the following:
>
>     rcrun command script [script2] [script3] ...
>
> where 'command' is one of 'disable', 'start', etc. This syntax allows to
> apply
> the same operation to multiple rc scripts at once which is very handy (at
> least
> to me). Also, this kind of syntax is similar to the one used in systemd
> with
> the sysctl tool for instance. In this matter, service(8) syntax is
> different:
>
>     service script command
>
> This syntax means that you cannot restart or do whatever command at once
> for
> multiple scripts. On the other hand, if we had to add the possibility to
> add
> arguments to the script this could be easily done this way:
>
>     service script command arg1 arg2 ...
>
> So I tried to think about a syntax for rcrun(8) that would allow it to pass
> arguments while still being able to apply a command to multiple scripts at
> once.  This is the idea that came to my mind: add a prefix to arguments so
> as
> to differentiate arguments from scripts names. For instance:
>
>     rcrun command script1 :arg1 :arg2 script2 script3 :arg1 :arg2
>
> In this example, ":" is used as the arguments prefix.  I see several
> advantages
> to this syntax:
>
> * It is retro-compatible to current rcrun(8) syntax meaning that it won't
> break
>   users's own scripts or workflow.
> * It allies best of both worlds (service(8) and rcrun(8) current syntax).
> * It is easy to implement.
>
> If someone has an other/better idea, I would like to hear about it. If, on
> the
> other hand it reaches a consensus, then I volunteer for this task too.
> However, there are more things I would need to know about before
> processing.
> procctl(2) and some other features were added recently and I would need to
> know
> where this is going and what changes it'll bring to rcrun(8) and all of
> what it
> implies (parallel starting of services, and so on).
>
> Robin Hahling (Rolinh)
>
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