Subject: Re: On /dev/console, /dev/constty and the TIOCCONS ioctl
To: <>
From: David Laight <david@l8s.co.uk>
List: tech-kern
Date: 10/04/2003 09:02:46
> 
> Please revert these changes, at least until they get discussed.

I've reverted the change to /etc/ttys - the only user-visible part.

> This is an area of the kernel that if you do not feel fully comfortable
> what's going on, you shouldn't be changing.

Indeed - it has taken me 2 days to work out what it going on, after I
realised why what I was trying to do didn't work.

> > It also makes it possible to log in on the 'console' while xconsole
> > (or similar) is running - a problem someone else mentioned yesterday.
> > 
> > Without the change it is impossible for a program running from the console
> > to output data to the console if TIOCCONS has been used to transfer kernel
> > messages to a pty.
> 
> Uhm, why not just use the real devices? Once you've installed, your 
> console shouldn't be moving around, so using ttyE0 or tty0 or some such 
> isn't a big deal.

Unless there is a 'magic' way to make the console getty run on the
underlying console device (instead on /dev/console) this doesn't work.

> Did you verify that revoke works right? Also, what are the semantics of 
> something opening /dev/console and something running on /dev/constty?

Much the same as those of something running on /dev/console and /dev/ttyE0

> Please revert it, and post a diff. While reverting would be volintary, if 
> you don't, you're setting a precident of, "It's ok because I committed 
> it." That doesn't do well for our code quality or peer review.

I did wonder if someone would ask this...


	David

-- 
David Laight: david@l8s.co.uk