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

From: Jon Smirl
Date: Mon Jul 10 2006 - 08:40:46 EST


On 7/10/06, Alan Cox <alan@xxxxxxxxxxxxxxxxxxx> 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@xxxxxxxxx> 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@xxxxxxxxx
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