Re: [PATCH v8 04/20] cachefiles: notify user daemon when withdrawing cookie

From: David Howells
Date: Mon Apr 11 2022 - 09:42:51 EST


JeffleXu <jefflexu@xxxxxxxxxxxxxxxxx> wrote:

> >
> >> + if (fd == 0)
> >> + return -ENOENT;
> >
> > 0 is a valid fd.
>
> Yeah, but IMHO fd 0 is always for stdin? I think the allocated anon_fd
> won't install at fd 0. Please correct me if I'm wrong.

If someone has closed 0, then you'll get 0 next, I'm pretty sure. Try it and
see.

> In fact I wanna use "fd == 0" as the initial state as struct
> cachefiles_object is allocated with kmem_cache_zalloc().

I would suggest presetting it to something like -2 to avoid confusion.

David