Re: [RFC PATCH] fs: allow open(dir, O_TMPFILE|..., 0) with mode 0

From: Andy Lutomirski
Date: Thu Oct 30 2014 - 20:01:59 EST


On Thu, Oct 30, 2014 at 3:58 PM, Linus Torvalds
<torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:
> On Thu, Oct 30, 2014 at 3:48 PM, Linus Torvalds
> <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:
>>
>> Agreed. Will apply and add the stable cc.
>
> Ho humm. Thinking about this some more, I'm starting to wonder. Not
> about this patch per se (open on a newly created file should indeed
> succeed regardless), but about the horrible glibc behavior of screwing
> up the third argument.
>
> If you want to do O_TMPFILE + linkat() (or some eventual future
> flink()), the mode really matters. So this idiotic glibc behavior of
> only forwarding the third argument if O_CREAT is set seems to be a
> bug.

We could bite the bullet and add a tmpfile syscall. /me ducks

>
> Why the hell does glibc think it's a good idea to intersect system
> call semantics? It's not a good idea - it's just stupid in the
> extreme. And in this case it seems to actively breaks things.

Uh, because it's glibc? Or because it's trying not to screw up and on
some system where overrunning va_arg is terrible?

>
> Linus



--
Andy Lutomirski
AMA Capital Management, LLC
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