Subject: Re: foo_init()s in main() [was: CVS commit: src/sys]
To: Martin Husemann <firstname.lastname@example.org>
From: Simon Burge <email@example.com>
Date: 11/22/2005 20:50:32
Martin Husemann wrote:
> On Tue, Nov 22, 2005 at 11:29:35AM +1100, Simon Burge wrote:
> > It really seems like we should do something to automate this, say based
> > on the FreeBSD sysinit stuff or linksets or something.
> Yes, we should.
> Could anyone give a summary of "FreeBSD sysinit" stuff?
In a very brief nut-shell there's a macro SYSINIT:
#define SYSINIT(uniquifier, subsystem, order, func, ident) \
which builds a link set of initialisation functions.
"uniquifier" is used to build the link set variable name. "subsystem" is
a numeric constant that defines the order of the function in the startup
sequence . "order" sorts orders within a subsystem . "func" is the
function, and "ident" appears to be an arg to "func".
To pick an example at random, net/route.c then says:
SYSINIT(route, SI_SUB_PROTO_DOMAIN, SI_ORDER_THIRD, route_init, 0);
The function that then iterates over the link set of initialisation
functions replaces what is our main() in init_main.c.
Note that this is just based on a glance at the FreeBSD code. I may be
entirely wrong about how this works :-)
 - see sysinit_sub_id in
 - see sysinit_elem_order in
Simon Burge <firstname.lastname@example.org>
NetBSD Support and Service: http://www.wasabisystems.com/