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Re: bash sets O_NONBLOCK on pts

From Stephane Chazelas <stephane.chazelas@gmail.com>
Newsgroups gnu.bash.bug
Subject Re: bash sets O_NONBLOCK on pts
Date 2019-10-03 19:23 +0100
Message-ID <mailman.899.1570127117.2651.bug-bash@gnu.org> (permalink)
References <CAGnkfhx6xvuhvfWYzy11xHt=qWg5We9GKLmj0fN6JhjGtov5rw@mail.gmail.com> <20191002153826.vgn3qbtztgulgyef@chaz.gmail.com> <5fae676d-5652-17e8-652f-b793e8e6b8e5@case.edu> <20191003182300.cghzq7wvjfdlw5a7@chaz.gmail.com>

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2019-10-03 13:58:40 -0400, Chet Ramey:
> On 10/2/19 11:38 AM, Stephane Chazelas wrote:
> 
> > BTW, what's the point of the check_dev_tty() function? It seems
> > it just attempts to open the tty (the controlling one or the one
> > open on stdin), closes it, but doesn't return anything about the
> > success of failure in doing so.
> 
> It's to make up for an old bug that's probably gone everywhere. Back
> in the day, there were systems and services that would start interactive
> shells without a controlling terminal. Opening and closing /dev/tty
> forced the controlling terminal to be allocated.
[...]

Thanks.

I suspected it may be something like that. Though I thought,
without actually double-checking it, that the rest of the code
would end up opening the terminal device (without O_NOCTTY) anyway.

It may be worth adding a comment to document that purpose of the
function, and maybe rename it to something like
control_tty_if_not_already_controlled or something that more
accurately describes its intent.

-- 
Stephane

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Re: bash sets O_NONBLOCK on pts Stephane Chazelas <stephane.chazelas@gmail.com> - 2019-10-03 19:23 +0100

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