From owner-freebsd-current@FreeBSD.ORG  Sat Jun 12 07:15:10 2004
Return-Path: <owner-freebsd-current@FreeBSD.ORG>
Delivered-To: freebsd-current@freebsd.org
Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125])
	by hub.freebsd.org (Postfix) with ESMTP id 24C5216A4CE
	for <current@freebsd.org>; Sat, 12 Jun 2004 07:15:10 +0000 (GMT)
Received: from critter.freebsd.dk (critter.freebsd.dk [212.242.86.163])
	by mx1.FreeBSD.org (Postfix) with ESMTP id 7D03743D1D
	for <current@freebsd.org>; Sat, 12 Jun 2004 07:15:09 +0000 (GMT)
	(envelope-from phk@phk.freebsd.dk)
Received: from critter.freebsd.dk (localhost [127.0.0.1])
	by critter.freebsd.dk (8.12.11/8.12.11) with ESMTP id i5C7EgXU077507;
	Sat, 12 Jun 2004 09:14:42 +0200 (CEST)
	(envelope-from phk@phk.freebsd.dk)
To: Dan Nelson <dnelson@allantgroup.com>
From: "Poul-Henning Kamp" <phk@phk.freebsd.dk>
In-Reply-To: Your message of "Fri, 11 Jun 2004 14:48:09 CDT."
             <20040611194808.GA55868@dan.emsphone.com> 
Date: Sat, 12 Jun 2004 09:14:42 +0200
Message-ID: <77506.1087024482@critter.freebsd.dk>
cc: current@freebsd.org
Subject: Re: Recent tty changes and snp 
X-BeenThere: freebsd-current@freebsd.org
X-Mailman-Version: 2.1.1
Precedence: list
List-Id: Discussions about the use of FreeBSD-current
	<freebsd-current.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-current>,
	<mailto:freebsd-current-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-current>
List-Post: <mailto:freebsd-current@freebsd.org>
List-Help: <mailto:freebsd-current-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-current>,
	<mailto:freebsd-current-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Sat, 12 Jun 2004 07:15:10 -0000

In message <20040611194808.GA55868@dan.emsphone.com>, Dan Nelson writes:
>
>I think the snp device got left out of the recent struct tty changes; I
>get the following panic when running "watch -W /dev/sometty" and typing
>a character.  Read-only watching a tty also causes a panic when I start
>typing on the real tty.

This is not intentional breakage, but it may be unavoidable breakage :-(

Snoop(4) is great functionality and I would have killed to have it
several times along my career, unfortunately its implementation is
a POS.

I'm currently pondering using bpf(4) for the task instead, but the
uneven layering of the tty layer has not offered me a clearcut place
to stick the code yet.

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.