Re: [RFC] O_NOACC: open without any access

From: Christoph Hellwig
Date: Tue Jun 23 2009 - 10:34:23 EST

On Tue, Jun 23, 2009 at 04:12:22PM +0200, Miklos Szeredi wrote:
> > an issue ioctls + stat / etc on it ut not actually read/write it.
> Two differences between open("foo", 3) and open("foo", O_NOACC):
> 1) open with "3" requires _read_and_write_ permissions on foo, but
> does not allow either read or write. Not sure what the logic in
> that, but that's the way it has always been.

Which is a quite sensible requirement if we want to do ioctls.

> 2) open with "3" calls driver's ->open() with any side effect that
> may have. Open with O_NOACC doesn't do that, and hence if we
> want to allow ioctls they need a new interface which gets a
> "struct path" instead of a "struct file".

Well, we'll need ->open to support ioctls, and I think it's good to go
down that road.

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