Messages in this thread | | | Date | Tue, 22 May 2001 10:24:53 -0500 (CDT) | From | Oliver Xymoron <> | Subject | Re: Why side-effects on open(2) are evil. (was Re: [RFD w/info-PATCH]device arguments from lookup) |
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On Mon, 21 May 2001, Daniel Phillips wrote:
> On Monday 21 May 2001 19:16, Oliver Xymoron wrote: > > What I'd like to see: > > > > - An interface for registering an array of related devices (almost > > always two: raw and ctl) and their legacy device numbers with a > > single userspace callout that does whatever /dev/ creation needs to > > be done. Thus, naming and permissions live in user space. No "device > > node is also a directory" weirdness... > > Could you be specific about what is weird about it?
*boggle*
Without precedent in any other UNIX? Or other operating systems, for that matter? Can you honestly say it doesn't strike you as weird? It's beating the least surprise rule with a big stick, fercryinoutloud.
Ok, so technically UNIX directories were once just files. But it's been a long time since people thought exposing that implementation detail was a good idea, and anyway, it's the opposite situation (and no longer true on modern fses).
I don't think it's likely to be even workable. Just consider the directory entry for a moment - is it going to be marked d or [cb]? If it doesn't have the directory bit set, Midnight commander won't let me look at it, and I wouldn't blame cd or ls for complaining. If it does have the 'd' bit set, I wouldn't blame cp, tar, find, or a million other programs if they did the wrong thing. They've had 30 years to expect that files aren't directories. They're going to act weird.
Linus has been kicking this idea around for a couple years now and it's still a cute solution looking for a problem. It just doesn't belong in UNIX.
More importantly, there's no call for the weirdness. Look, we've already got to have a userspace callout for new devices so that we can do config, firmware downloading, automounting, etc. There's no reason we can't stick the rest of the dynamic /dev/ magic in userspace with the same mechanism.
-- "Love the dolphins," she advised him. "Write by W.A.S.T.E.."
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