Subject: Re: correct "direction" of barriers in rc.d
To: None <tech-userlevel@netbsd.org>
From: Greg A. Woods <woods@weird.com>
List: tech-userlevel
Date: 03/20/2002 15:41:21
[ On Wednesday, March 20, 2002 at 10:33:21 (-0800), Jason R Thorpe wrote: ]
> Subject: correct "direction" of barriers in rc.d
>
> Now, Luke thinks this is an abuse of the BEFORE keyword.  However, I
> strongly disagree.  Rather, I think it actually describes what the
> real requirement is in a straightforward way.  I also think that REQUIRE
> should only list *actual requirements*, e.g. mountd requires rpcbind.

I agree (with Jason).  These "barrier" scripts are just nodes in the
dependency graph that allow common dependencies to be expressed without
having to maintain multiple lists of them in the places where they're
needed.  They aren't optimal dependencies, just collections based on
common assumptions built upon experience.

(Since the "BEFORE" keyword isn't really very well documented I'm
confused as to how using it in the way you propose could be considered
an "abuse".  :-)

Presumably these common dependencies could be implemented as sourced
files containing "REQUIRE" keywords instead of as fake scripts, but that
would either make 'rcorder' more complex (and thus directly in
opposition to one of rcorder's design goals) or require some sort of
pre-processing step, which from /etc/rc's P.O.V. is also much too much
more complex.

(as for the order changes, well they'd better be innocuous or else there
are errors in the definitions of the dependencies in the first place!)

-- 
								Greg A. Woods

+1 416 218-0098;  <gwoods@acm.org>;  <g.a.woods@ieee.org>;  <woods@robohack.ca>
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