Re: 2.6.8-rc2-mm1

Johannes Stezenbach
2004-07-29T00:07:40Z

Andrew Morton wrote:
> Johannes Stezenbach <js@convergence.de> wrote:
> >
> > This is a hack introduced by someone years ago. The "pointer" is
> > actually an integer argument, e.g. in include/linux/dvb/audio.h:
> >
> > #define AUDIO_SET_MUTE _IO('o', 6)
> >
> > actually takes an integer argument (!0 mute, 0 unmute), so one can write
> >
> > if (ioctl(fd, AUDIO_SET_MUTE, 1) == -1)
> > perror("mute");
>
> Is it a boolean argument?
>
> If so, we could change the code to do
>
> parg = (void *)(arg ? 1 : 0);
>
> so if someone dereferences it they'll get a nice oops.

Unfortunately there are a few more ioctls which use enums,
e.g. AUDIO_CHANNEL_SELECT has an argument of type
audio_channel_select_t etc. (yes, I know, those typedefs
should go). Or even DMX_SET_BUFFER_SIZE...

Johannes