From mboxrd@z Thu Jan  1 00:00:00 1970
From: "Dmitry V. Levin" <ldv@altlinux.org>
Subject: Re: [PATCH v4 4/5] drm: Add decoding of i915 ioctls
Date: Wed, 9 Sep 2015 14:52:18 +0300
Message-ID: <20150909115218.GD6119@altlinux.org>
References: <1440420170-13337-1-git-send-email-patrik.jakobsson@linux.intel.com>
 <1440420170-13337-5-git-send-email-patrik.jakobsson@linux.intel.com>
 <20150908011811.GB17781@altlinux.org>
 <20150908013052.GC17781@altlinux.org>
Mime-Version: 1.0
Content-Type: multipart/mixed; boundary="===============1240821817=="
Return-path: <intel-gfx-bounces@lists.freedesktop.org>
Received: from pegasus3.altlinux.org (pegasus3.altlinux.org [194.107.17.103])
 by gabe.freedesktop.org (Postfix) with ESMTP id DA6186E03B
 for <intel-gfx@lists.freedesktop.org>; Wed,  9 Sep 2015 04:52:20 -0700 (PDT)
In-Reply-To: <20150908013052.GC17781@altlinux.org>
List-Unsubscribe: <http://lists.freedesktop.org/mailman/options/intel-gfx>,
 <mailto:intel-gfx-request@lists.freedesktop.org?subject=unsubscribe>
List-Archive: <http://lists.freedesktop.org/archives/intel-gfx>
List-Post: <mailto:intel-gfx@lists.freedesktop.org>
List-Help: <mailto:intel-gfx-request@lists.freedesktop.org?subject=help>
List-Subscribe: <http://lists.freedesktop.org/mailman/listinfo/intel-gfx>,
 <mailto:intel-gfx-request@lists.freedesktop.org?subject=subscribe>
Errors-To: intel-gfx-bounces@lists.freedesktop.org
Sender: "Intel-gfx" <intel-gfx-bounces@lists.freedesktop.org>
To: Patrik Jakobsson <patrik.jakobsson@linux.intel.com>
Cc: intel-gfx@lists.freedesktop.org, strace-devel@lists.sourceforge.net
List-Id: intel-gfx@lists.freedesktop.org


--===============1240821817==
Content-Type: multipart/signed; micalg=pgp-sha1;
	protocol="application/pgp-signature"; boundary="mSxgbZZZvrAyzONB"
Content-Disposition: inline


--mSxgbZZZvrAyzONB
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
Content-Transfer-Encoding: quoted-printable

On Tue, Sep 08, 2015 at 04:30:52AM +0300, Dmitry V. Levin wrote:
> On Tue, Sep 08, 2015 at 04:18:11AM +0300, Dmitry V. Levin wrote:
> [...]
> > So the whole function should look smth like this:
> >=20
> > static int i915_getparam(struct tcb *tcp, const unsigned int code, long=
 arg)
> > {
> > 	struct drm_i915_getparam param;
> >=20
> > 	if (entering(tcp)) {
> > 		if (umove_or_printaddr(tcp, arg, &param))
> > 			return RVAL_DECODED | 1;
> > 		tprints(", {param=3D");
>=20
> or rather
> 		tprints(", ");
> 		if (umove_or_printaddr(tcp, arg, &param))
> 			return RVAL_DECODED | 1;
> 		tprints("{param=3D");

or rather

static int
i915_getparam(struct tcb *tcp, const unsigned int code, const long arg)
{
	struct drm_i915_getparam param;
	int value;

	if (entering(tcp)) {
		tprints(", ");
		if (umove_or_printaddr(tcp, arg, &param))
			return RVAL_DECODED | 1;
		tprints("{param=3D");
		printxval(drm_i915_getparams, param.param, "I915_PARAM_???");
		return 0;
	}

	if (!umove(tcp, arg, &param)) {
		tprints(", value=3D");
		if (!umove_or_printaddr(tcp, (long) param.value, &value)) {
			switch (param.param) {
			case I915_PARAM_CHIPSET_ID:
				tprintf("[%#04x]", value);
				break;
			default:
				tprintf("[%d]", value);
			}
		}
	}
	tprints("}");
	return 1;
}

Note that those structure members that are set by the kernel on exiting
syscall shouldn't normally be printed in case of syserror(tcp).

In case of i915_getparam, no extra check is needed because param.value is
an address supplied by userspace and umove_or_printaddr already performs
all necessary checks, but in other IOWR parsers you might want to use
	if (!syserror(tcp) && !umove(tcp, arg, &param)) {
instead.


--=20
ldv

--mSxgbZZZvrAyzONB
Content-Type: application/pgp-signature

-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1

iEYEARECAAYFAlXwHXIACgkQfKvmrJ41Nh5UJwCfbQzxOdPq3oZgUMEa0tOGtx2p
M2cAnAytGTARvo6N8ktRzUgs/Jhz+sXz
=4XKG
-----END PGP SIGNATURE-----

--mSxgbZZZvrAyzONB--

--===============1240821817==
Content-Type: text/plain; charset="utf-8"
MIME-Version: 1.0
Content-Transfer-Encoding: base64
Content-Disposition: inline

X19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX18KSW50ZWwtZ2Z4
IG1haWxpbmcgbGlzdApJbnRlbC1nZnhAbGlzdHMuZnJlZWRlc2t0b3Aub3JnCmh0dHA6Ly9saXN0
cy5mcmVlZGVza3RvcC5vcmcvbWFpbG1hbi9saXN0aW5mby9pbnRlbC1nZngK

--===============1240821817==--