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Date:      Wed, 20 Aug 2014 11:16:26 -0700
From:      Garrett Cooper <yaneurabeya@gmail.com>
To:        Alfred Perlstein <bright@mu.org>
Cc:        "freebsd-current@freebsd.org" <freebsd-current@freebsd.org>
Subject:   Re: RFC: Remove pty(4)
Message-ID:  <9D23D164-E7D1-40EB-91AE-FD5DA1F2EB65@gmail.com>
In-Reply-To: <53F4E37A.6020702@mu.org>
References:  <CACYV=-E1BA3rHP5s%2BCs-X-J5CNAaSNxDgqPkgnJu3uUXCyaUGA@mail.gmail.com> <53F4E37A.6020702@mu.org>

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> On Aug 20, 2014, at 11:05, Alfred Perlstein <bright@mu.org> wrote:
>=20
>> 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 <=3D 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.
>>=20
>> The code review for the proposed change can be found here:
>> https://reviews.freebsd.org/D659
>>=20
>> 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 ju=
st 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 ma=
intaining the old interface?

    Doing this would also break login shells, xterms, etc, right? Some compa=
nies I worked for built their appliance products on newer OSes, and they wer=
e based off of 6 and 7. This seems like something that deserves being tossed=
 into the compat layer if it's something that can be converted over to the n=
ew interface.
Thanks!
-Garrett=



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