RFC: Remove pty(4)

Bryan Drewery bdrewery at FreeBSD.org
Wed Aug 20 18:19:38 UTC 2014

On 8/20/2014 1:13 PM, Julian Elischer wrote:
> 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 agree with Alfred.
> breaking old jails is a no no.
> many people still use them. Me included.
> I sometimes run jails back to 1.1,
> not everything works, but enough does to build 1.1 binaries for certain
> devices.

+1 to keeping compat.

Bryan Drewery

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