Re: FAT, NTFS, CIFS and DOS attributes

From: tridge
Date: Mon Jan 03 2005 - 20:18:19 EST


> The slightly stronger reason is basically the same reason why we don't
> stuff a bunch of things into a struct stat and call a single system call
> to change a bunch of attributes

yes, and if we want this to be a good API then we'd use something like
a bitmask to indicate what fields to update so we can update them in
groups in a raceless fashion, but that would require that the kernel
understand the internals of these structures. I didn't have that
luxury, so I grouped them in the way that best matched the common use
of the attributes.

> you don't want to have to change them all every time, and by
> putting them all in the same structure that's your only option,
> since setxattr() doesn't allow you to mask and merge.

can you tell me who you imagining will be using these attributes apart
from Samba, Wine and backup/restore apps?

>
> Incidentally, the document you pointed me to wasn't clear on the
> endianness convention.

It's little-endian NDR. For a full description of NDR in all its gory
details see http://www.opengroup.org/onlinepubs/9629399/chap14.htm

NDR seems like overkill at first, until you start to look at security
descriptors. They are very complex beasts, and using IDL/NDR makes it
much easier (in fact, security descriptors need some minor
enhancements to NDR to encode them the same way windows does).

Cheers, Tridge
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