Messages in this thread |  | | | From | Daniel Phillips <> | | Subject | Re: Why side-effects on open(2) are evil. (was Re: [RFD w/info-PATCH]device arguments from lookup) | | Date | Tue, 22 May 2001 22:22:35 +0200 |
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On Tuesday 22 May 2001 19:49, Oliver Xymoron wrote: > On Tue, 22 May 2001, Daniel Phillips wrote: > > > 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]? > > > > It's going to be marked 'd', it's a directory, not a file. > > Are we talking about the same proposal? The one where I can open > /dev/dsp and /dev/dsp/ctl? But I can still do 'cat /dev/hda > > /dev/dsp'?
We already support read/write on directories in the VFS, that's not a problem.
> It's still a file. If it's not a file anymore, it ain't UNIX.
It's a file with the directory bit set, I believe that's UNIX.
> > > 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. > > > > No problem, it's a directory. > > > > > 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. > > > > Hmm, ok, do we still have any *technical* reasons? > > If you define *technical* to not include design, sure.
Sorry, I don't see what you mean, do you mean the design is difficult? > Oh, did I mention unnecessary, solvable in userspace?
That's exactly the point: the generic filesystem allows all the funny-shaped stuff to be dealt with in user space. The filesystem itself is lovely and clean.
BTW, I didn't realize I was reinventing Linus's wheel, this just seemed very obvious and natural to me. So I had to believe there's a technical obstacle somewhere.
Has anyone written code to demonstrate the idea?
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