Re: [PATCH] ioctl entries for joystick in compat_ioctl.h

[Vojtech Pavlik <vojtech@suse.cz>]

On Fri, Sep 12, 2003 at 11:13:06PM +0200, Pavel Machek wrote:

> > > > I wanted to use a joystick on my sparc64 workstation, and discovered that the
> > > > joystick driver uses simple ioclt that are safe to pass from 32bit user space
> > > > to 64bit kernel space. My patch adds the necessary entries in compat_ioctl.h.
> > > > 
> > > > There is only one missing ioctl in the patch. The ioctl is defined like this:
> > > > #define JSIOCGNAME(len)         _IOC(_IOC_READ, 'j', 0x13, len)
> > > > so the command does not have a fixed value. I dont know how to handle this one,
> > > > but it is only used to get the joystick name, all the applications I tried work
> > > > well even if this ioctl fails.
> > > 
> > > Well, whoever invented that JSIOCGNAME should be shot. That is not
> > > single ioctl, its 2^14 of them!
> > 
> > Well, who could ever have known that this will be a problem in 1998?
> > It's not the only ioctl done this way.
> 
> So it was you? :-)

Yes. :)

> I believe ultrasparcs were around in '98. Anyway, what are other
> ioctls doing this? They look pretty problematic from compat_ioctl
> perspective.

I don't remember - I know I just copied the concept from elsewhere.
I'm sure you'll be able to grep for it.

> We could do better by pushing compat handler down to the drivers for
> ugly cases like this...

-- 
Vojtech Pavlik
SuSE Labs, SuSE CR