Messages in this thread | | | Date | Wed, 9 Aug 2006 15:11:00 +0100 | From | Al Viro <> | Subject | Re: [PATCH] move IMMUTABLE|APPEND checks to notify_change() |
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On Wed, Aug 09, 2006 at 11:15:12AM +0400, Dmitry Mishin wrote: > Do you meant utimes(file, NULL)? > But is it correct behaviour? Why then do you get -EPERM on utimes(file, smth) > if the file is append-only? And why do you get -EACCESS on utimes(file, > NULL), if this file is immutable? > > Could you explain, why is it done so?
RTFPOSIX...
Short version: * immutable files are immutable, including metadata * append-only files may be touched (when you write to the end), which means that you can touch them. Which is what utimes(file, NULL) does. * you can not truncate append-only file, overwrite already written data or set timestamps to arbitrary values.
That's where the difference between utimes(file, NULL) and utimes(file, p) is - the former basically is a write-without-write ("touch foo") and the latter directly assigns to timestamps. Permissions needed for these are obviously different.
Please, read POSIX/SuS when modifying behaviour of syscalls. Really. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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