Messages in this thread | | | Date | Tue, 6 Nov 2007 12:47:38 +0100 | From | Adrian Bunk <> | Subject | Re: [PATCH] Smackv10: Smack rules grammar + their stateful parser |
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On Tue, Nov 06, 2007 at 01:34:05PM +0200, Ahmed S. Darwish wrote: > Hi, > > On Tue, Nov 06, 2007 at 09:56:51AM +0100, Adrian Bunk wrote: > > On Tue, Nov 06, 2007 at 03:26:12AM -0500, Kyle Moffett wrote: > > > On Nov 06, 2007, at 01:33:05, Adrian Bunk wrote: > > >> Can you limit this to 7bit ASCII and use isascii() somewhere? > > >> > > >> Otherwise I'd expect funny things to happen when you e.g. use isspace() on > > >> the UTF-8 encoded character ??. > > > > > > Actually, you don't need to. You tell them it expects UTF-8 encoded > > > strings and be done with it. All US-ASCII characters from 0 through 127 > > > (IE: high bit clear) are exactly the same in UTF-8, and UTF-8 special > > > characters have the high bit set in all bytes. Therefore you just assume > > > that anything with the high bit set is part of a word and you can handle > > > basic UTF-8. (It doesn't work on special UTF-8 space characters like > > > nonbreaking space and similar, but handling those is significantly more > > > complicated). > > > > The documentations says: > > "Smack labels cannot contain unprintable characters or the "/" (slash) > > character." > > > > What you propose might contain unprintable characters, and it might even > > be invalid UTF-8. > > As far as I understand the problem now, isspace() accepts the 0xa0 > character which might collide with some of UTF-8 encoded characters > cause the high bit is set. > > I used "if (!isspace(c) && !isgraph(c)) return -EINVAL;" to test > rules' characters validity which seems not enough. I'll add !isascii(c) > in the condition and ask Casey to change the documentation to be > something like: > > Smack labels are represented in ASCII characters, they cannot contain > unprintable characters or the '/' (slash) character. > > and in write(): > if (!isascii(c) return -EINVAL; > if (!isspace(c) && !isgraph(c)) return -EINVAL; > > This satisfy above customized labels rule, right ?
It should work for all charsets you'll usually have to handle.
It would not work if someone would e.g. give you UTF-16 encoded strings, but I don't see this happening in practice.
> Regards,
cu Adrian
--
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