Re: [PATCH 1/1] UIO: Add a write() function to enable/disable interrupts

Hans J. Koch
2008-05-23T08:52:19Z

Am Fri, 23 May 2008 07:41:15 +0200
schrieb Uwe Kleine-König <Uwe.Kleine-Koenig@digi.com>:

> Hello Tom,
>
> Tom Spink wrote:
> > The added benefit is that the code becomes less complex, as you
> > don't have to check buffer sizes and copy the integer from
> > userspace.
> AFAIK this is wrong. You need to copy the integer from userspace in
> uio_ioctl. Actually it's a value coming from user space, so you need
> to do it somewhere.

True. Also note that this is not type-safe. All ioctl calls blindly
trust userspace to pass in correct data. This has to be tolerated for
ancient well-known filesystem ioctls, because you'd break almost all of
userspace if you changed that, but we certainly don't want to add new
stuff to this mess.

Thanks,
Hans