Re: [PATCH] Open Firmware device tree virtual filesystem

From: Segher Boessenkool
Date: Mon Jan 01 2007 - 18:54:10 EST


If you *really* want (the option of) showing things as text
in the filesystem, you better make it so that there is a
one-to-one translation back to binary. For example, what
does this mean, is it a text string or two bytes:

01.02

Yes you as a user can guess, but scripts can't (reliably).

We have some extensive code in fs/openpromfs/inode.c that
determines whether a property is text or not. I can't
guarentee it works %100, but it's very context dependant
(only the driver "knows") but it works for all the cases
I've tried.

It's still a heuristic, I don't think the kernel should be
doing things like this; leave the guesswork to userland,
where different users can guess in different ways if they
want/need.

Some real life properties contain _both_ a binary part and
a text part, btw.

I really think you're making a mountain out of a mole hill, to be
honest :-)

Heh. There is one big problem: text representation is useless
(to scripts etc.) unless it can be transformed back to binary;
i.e., it has to be possible to reliably detect _how_ some
property is represented into text, something that cannot be
done with how openpromfs handles it.


Segher

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