Re: [PATCH v3 4/5] drm: Add decoding of i915 ioctls

Dmitry V. Levin
2015-07-03T00:36:10Z

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On Wed, Jul 01, 2015 at 02:52:47PM +0200, Patrik Jakobsson wrote:
[...]
> --- a/drm.c
> +++ b/drm.c
> @@ -35,6 +35,9 @@
>
> #define DRM_MAX_NAME_LEN 128
>
> +extern int drm_i915_decode_number(struct tcb *tcp, unsigned int arg);

Please rename "arg" to "code", and ...

> +extern int drm_i915_ioctl(struct tcb *tcp, const unsigned int code, long arg);

... move both declarations to defs.h to make them visible also
in the file where these functions are defined.

[...]
> +static int i915_setparam(struct tcb *tcp, const unsigned int code, long arg)
> +{
> + struct drm_i915_setparam param;
> +
> + if (entering(tcp)) {
> + if (umove(tcp, arg, &param))
> + return 0;
> +
> + tprints(", {param=");
> + printxval(drm_i915_setparams, param.param, "I915_PARAM_???");
> + tprintf(", value=%d}", param.value);
> + }
> +
> + return 1;
> +}

In this and most of other parsers of _IOC_WRITE ioctls added by this and
the next patches, any error in parser that leads to "return 0" will result
to disabled "arg" decoding, including the fallback decoding performed by
sys_ioctl.

Maybe it's time to deal with this issue in a more generic way.

--
ldv

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