RE: [PATCH v3 3/4] vsscanf(): do not skip spaces

[David Laight]

From: Rasmus Villemoes
> Sent: 12 June 2023 12:08
> 
> On 10/06/2023 22.40, Demi Marie Obenour wrote:
> > Passing spaces before e.g. an integer is usually
> > not intended.
> 
> Maybe, maybe not. But it's mandated by POSIX/C99.
> 
> And of course we are free to ignore that and implement our own semantics
> (though within the constraints that we really want -Wformat to help us),
> but there seems to be existing code in-tree that relies on this
> behavior. For example I think this will break
> fsl_sata_intr_coalescing_store() which uses a scanf format of "%u%u".
> 
> Sure, that could just say "%u %u" instead, but the point is that
> currently it doesn't. So without some reasonably thorough analysis
> across the tree, and updates of affected callers, NAK.

It would almost certainly need to be " %u %u" to allow for
userspace generating the input with "%6u %6u",

	David

-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)