Re: [Dan.Oscarsson@kiconsulting.se: Comments on NFSv4 rfc3010bis- 05 draft]

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From: Nicolas Williams (Nicolas.Williams@sun.com)
Date: 01/24/03-03:12:18 PM Z


Date: Fri, 24 Jan 2003 15:12:18 -0600
From: Nicolas Williams <Nicolas.Williams@sun.com>
Subject: Re: [Dan.Oscarsson@kiconsulting.se: Comments on NFSv4 rfc3010bis- 05 draft]
Message-ID: <20030124151218.E16765@binky.central.sun.com>

On Fri, Jan 24, 2003 at 01:00:43PM -0800, Mike Eisler wrote:
> Nicolas Williams wrote:
> > This is not my reading of the draft.
> > 
> > Section 11.1.1 clearly specifies what to do with respect to filenames
> > with equal names but different encoding [due to different normalization
> > forms used by the clients that create them].  Section 11.1.1 necessarily
> > requires that the server perform normalization of client inputs to some
> > form of the server's choosing.
> 
> I don't see the text. Section  11.1.4 says no normalization
> form is specified. Stringprep has tables B1 and B2. B1 is required
> to be processed, but I didn't see anything in stringprep that said that
> normalization went with table B1. Table B2 explicitly says KC, and B2
> is for dealing with case insensitive stuff. Section 3 of stringprpe (now
> RFC 3454) refers to Appendix B and the various tables. It says nothing
> about normization for B1, whereas it does say something about normalization
> with respect to B2 and B3.

Yes, but the requirements from section 11.1.1 about duplicate filenames
imply normalization, if not for stored file names, then during
comparison of file names.

> Now I am admittably quite ignorant on this topic, but it seems rather
> odd that B1 requires normalization (and according to RFC 3454, B1 is
> mandatory), and yet B3 is specified to allow applications to not use
> normalization when case matching. Section 2 of RFC 3454 distinguishes between
> the mapping phase and the normalization phase, and mapping is the topic
> of section 3 and appendix B. So if your reading is correct,
> then it seems to me RFC 3454 has a paradox.
> 
> We apparently need an "RFC 3454 for Dummies" document.

I was only referring to section 11.1.1, specifically: "Two valid
distinct UTF-8 strings might be the same after processing via the
utf8str_cs profile. If the strings are two names inside a directory, the
NFS version 4 server will need to either: ..."

If the server allows two (or more) files to have the same names but
different byte sequences (say, one UTF-8, NFD, the other UTF-8, NFC),
then we'll have the "how do I delete a file named '-i'?" problem
magnified to "I see a file named 'bár' but when I type 'rm bár' it
doesn't work".  Or am I missing some text about utf8str_cs comparisons
having to be done over normalized forms of the comparison inputs??

(yes, above I did not use UTF-8 for "bár" - my apologies)

> 	-mre

Cheers,

Nico
-- 


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