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Date:      Wed, 09 Sep 1998 12:33:57 -0700
From:      Mike Smith <mike@smith.net.au>
To:        Andrzej Bialecki <abial@nask.pl>
Cc:        Poul-Henning Kamp <phk@critter.freebsd.dk>, freebsd-current@FreeBSD.ORG
Subject:   Re: Adding sysctl, part II 
Message-ID:  <199809091933.MAA00801@dingo.cdrom.com>
In-Reply-To: Your message of "Wed, 09 Sep 1998 14:54:22 %2B0200." <Pine.BSF.4.02A.9809091411140.21222-100000@korin.warman.org.pl> 

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> On Wed, 9 Sep 1998, Poul-Henning Kamp wrote:
> 
> > 
> > >Well, I kind of figured out I probably need to use SYSCTL_PROC, and
> > >applied the following patch to machdep.c:
> > 
> > Look at the 
> > 	DDB_SHOW_COMMAND(msgbuf, db_show_msgbuf)
> > 	{
> > 
> > at the bottom of kern/subr_prf.c
> 
> Ah! I see it now - I should be glad it didn't explode in my face...
> 
> It's still unclear to me, however, what should I do to retrieve not only
> the struct msgbuf (which the msgbufp points to), but the buffer itself as
> well. If I understand this correctly, once I retrieved the struct msgbuf
> contents, the msgbufp->msg_ptr is useless because it points to the data in
> kernel space, so I need to make another call to retrieve the buffer
> contents, right? The code in subr_prf.c can do this because it works in
> kernel space all the time, but I can't...

Try something like

static int
sysctl_msgbuf SYSCTL_HANDLER_ARGS
{
	return(sysctl_out(req, msgbufp, MSGBUFLEN));
}

SYSCTL_PROC(_kern, OID_AUTO, msgbuf, CTLFLAG_RD, NULL, NULL, 
            sysctl_msgbuf, "S,msgbuf", "kernel message buffer");

-- 
\\  Sometimes you're ahead,       \\  Mike Smith
\\  sometimes you're behind.      \\  mike@smith.net.au
\\  The race is long, and in the  \\  msmith@freebsd.org
\\  end it's only with yourself.  \\  msmith@cdrom.com



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