From owner-freebsd-current@FreeBSD.ORG Wed Aug 20 18:04:18 2014 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 09E32F36 for ; Wed, 20 Aug 2014 18:04:18 +0000 (UTC) Received: from elvis.mu.org (elvis.mu.org [192.203.228.196]) by mx1.freebsd.org (Postfix) with ESMTP id E9F963028 for ; Wed, 20 Aug 2014 18:04:17 +0000 (UTC) Received: from Alfreds-MacBook-Pro.local (unknown [12.69.234.201]) by elvis.mu.org (Postfix) with ESMTPSA id E7153346DE81 for ; Wed, 20 Aug 2014 11:04:16 -0700 (PDT) Message-ID: <53F4E37A.6020702@mu.org> Date: Wed, 20 Aug 2014 11:05:46 -0700 From: Alfred Perlstein User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.9; rv:31.0) Gecko/20100101 Thunderbird/31.0 MIME-Version: 1.0 To: freebsd-current@freebsd.org Subject: Re: RFC: Remove pty(4) References: In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 20 Aug 2014 18:04:18 -0000 On 8/20/14 11:00 AM, Davide Italiano wrote: > One of my personal goals for 11 is to get rid of cloning mechanism > entirely, and pty(4) is one of the few in-kernel drivers still relying > on such mechanism. > It's not possible, at least to my understanding, converting pty(4) to > cdevpriv(9) as happened with other drivers. This is mainly because we > always need a pair of devices (/dev/ptyXX and /dev/ttyXX) and > userspace loops over ptyXX and after it successfully opens it tries to > open the other one with the same suffix. So, having a single device is > not really enough. > My option, instead, is that of removing pty(4), which is nothing more > than a compatibility driver, and move pmtx(4) code somewhere else. > The main drawback of the removal of this is that it makes impossible > to run FreeBSD <= 7 jails and SSH into them. I personally don't > consider this a huge issue, in light of the fact that FreeBSD-7 has > been EOL for a long time, but I would like to hear other people > comments. > > The code review for the proposed change can be found here: > https://reviews.freebsd.org/D659 > > If I won't get any objection I'll commit this in one week time, i.e. > August 27th. > I don't think that we want to break userland apps pre-7.x. Do you mean just jails are broken? Or is all pre-7.x compat? I believe either is dicey. What is the reason for getting rid of cloning? What is the difficulty in maintaining the old interface? -Alfred