Re: (Semi-random) thoughts on device tree structure and devfs

[Masao Uebayashi <uebayasi%gmail.com@localhost>]

> I programm microcontrolers with a serial programmer. I use a serial
> connection to the target microcontroler for debugging. So I want to
> be able to read/write the serial port device node (e.g. /dev/tty03
> or /dev/ttyU0) directely. But I don't want other users grant access to
> my serial devices. So I chown the device node to user jkunz and make it
> read/writable by that user only.

Is it acceptable for you to do such things by some layering?  I don't
know how to do that exactly yet, but the point is you need a little
more resource to deal with   per-file configuration.

> The Linux devfs solved this problem with an init-script, that changed
> ownership and modes after each reboot. Looked a bit awkward to me when
> I had to deal with it.

A bit?  I thought udevfs's config file is totally inacceptable for
missiong critical embedded purposes.  Why do we have to learn a new
syntax to configure only a few device file permissions?

> Non-persistent ownership and modes of device nodes is a show stopper.

Sure.

Masao