Re: [PATCH] Clean up old names in tty code to current names

Jon Smirl
2006-07-10T12:41:52Z

On 7/10/06, Alan Cox <alan@lxorguk.ukuu.org.uk> wrote:
> Ar Llu, 2006-07-10 am 00:11 -0400, ysgrifennodd Jon Smirl:
> > Fix various places in the tty code to make it match the current naming system.
> > pty_slave_driver->driver_name = "pty_slave";
>
>
> NAK to just about all of this. Its gratuitous breaking of existing apps,
> it achieves nothing and some of it like the pty stuff is just plain
> incorrect anyway.

The whole naming scheme encoded into the tty code is incompatible with
udev. Udev allows renames and this code isn't aware of them.

I thought the idea behind udev was to remove all of this naming code
from the kernel and handle it in user space. So if I want legacy
device names I would add a section to /etc/udev to create them. Udev
is already capable of doing this.

> If you want to add sysfs interfaces to the tty code great, but please
> leave the existing, relied up, functional and effectively user space ABI
> tty files alone.

So far I haven't identified anything that is really needed that isn't
already available in sysfs.

It does seem that we are missing a user space library call for
converting a device number into a device name using the udev database.

On 7/9/06, Albert Cahalan <acahalan@gmail.com> wrote:
> BSD just uses devname(3) in libc, which asks the kernel via
> the kern.devname sysctl. So, /proc/sys/kern/devname for us.
> This is essentially what /proc/tty/drivers is today, except
> that FreeBSD standardized on a fully functional devfs.
>
> Solaris uses _ttyname_dev(dev_t,buf,bufsize), also in libc.
> This is horribly slow, involving a recursive search of
> directories listed in the /etc/ttysrch file. The interface
> is nice though. You get: ttyname, ttyname_r, _ttyname_dev.

--
Jon Smirl
jonsmirl@gmail.com