Re: [PATCH 3/3] Add a pair of system calls to make extended filestats available

From: Joel Becker
Date: Tue Jun 29 2010 - 18:51:20 EST


On Tue, Jun 29, 2010 at 11:36:56PM +0100, David Howells wrote:
> Ulrich Drepper <drepper@xxxxxxxxx> wrote:
> > And while you're at it, maybe some spare fields at the end are nice.
>
> I made it so that the syscall can return variable length data: the main xstat
> struct, plus extra records yet to be defined. They could even be variable
> length and assembled/disassembled with something like the control message
> macros for recvmsg().

The less variable length stuff the better, I think. At least,
for the stuff stat(2) already returns, you should have a fixed-size
structure. Even if I only pass the GIVE_ME_UIDS flag, I don't want to
have to deal with the variable size stuff until I've actually asked for
esoteric things. I'll know that the non-UIDS fields are garbage by the
fact that I didn't ask for them.

Joel

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Joel Becker
Consulting Software Developer
Oracle
E-mail: joel.becker@xxxxxxxxxx
Phone: (650) 506-8127
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