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From:   Juerg Haefliger <juerg.haefliger@canonical.com>
Date:   Thu, 20 May 2021 08:30:52 +0200
To:     Joe Perches <joe@perches.com>
Cc:     Juerg Haefliger <juerg.haefliger@canonical.com>,
        wim@linux-watchdog.org, linux@roeck-us.net, joel@jms.id.au,
        linux-watchdog@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org,
        linux-aspeed@lists.ozlabs.org, andrew@aj.id.au,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH] watchdog: Use sysfs_emit() and sysfs_emit_at() in
 "show" functions
Message-ID: <20210520083052.68a0e1d9@smeagol>
In-Reply-To: <f2e616645f311ccaf6e0acb996f8c4360a0480ec.camel@perches.com>
References: <20210511061812.480172-1-juergh@canonical.com>
        <f2e616645f311ccaf6e0acb996f8c4360a0480ec.camel@perches.com>
Organization: Canonical Ltd
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On Wed, 12 May 2021 21:48:37 -0700
Joe Perches <joe@perches.com> wrote:

> On Tue, 2021-05-11 at 08:18 +0200, Juerg Haefliger wrote:
> > Convert sprintf() in sysfs "show" functions to sysfs_emit() and
> > sysfs_emit_at() in order to check for buffer overruns in sysfs outputs.=
 =20
> []
> > diff --git a/drivers/watchdog/ziirave_wdt.c b/drivers/watchdog/ziirave_=
wdt.c =20
> []
> > @@ -445,8 +445,9 @@ static ssize_t ziirave_wdt_sysfs_show_firm(struct d=
evice *dev,
> > =C2=A0	if (ret)
> > =C2=A0		return ret;
> > =C2=A0
> >=20
> > -	ret =3D sprintf(buf, ZIIRAVE_FW_VERSION_FMT, w_priv->firmware_rev.maj=
or,
> > -		      w_priv->firmware_rev.minor);
> > +	ret =3D sysfs_emit(buf, ZIIRAVE_FW_VERSION_FMT,
> > +			 w_priv->firmware_rev.major,
> > +			 w_priv->firmware_rev.minor);
> > =C2=A0
> >=20
> > =C2=A0	mutex_unlock(&w_priv->sysfs_mutex);
> > =C2=A0
> >=20
> > @@ -468,8 +469,9 @@ static ssize_t ziirave_wdt_sysfs_show_boot(struct d=
evice *dev,
> > =C2=A0	if (ret)
> > =C2=A0		return ret;
> > =C2=A0
> >=20
> > -	ret =3D sprintf(buf, ZIIRAVE_BL_VERSION_FMT, w_priv->bootloader_rev.m=
ajor,
> > -		      w_priv->bootloader_rev.minor);
> > +	ret =3D sysfs_emit(buf, ZIIRAVE_BL_VERSION_FMT,
> > +			 w_priv->bootloader_rev.major,
> > +			 w_priv->bootloader_rev.minor);
> > =C2=A0
> >=20
> > =C2=A0	mutex_unlock(&w_priv->sysfs_mutex);
> > =C2=A0
> >=20
> > @@ -491,7 +493,7 @@ static ssize_t ziirave_wdt_sysfs_show_reason(struct=
 device *dev,
> > =C2=A0	if (ret)
> > =C2=A0		return ret;
> > =C2=A0
> >=20
> > -	ret =3D sprintf(buf, "%s", ziirave_reasons[w_priv->reset_reason]);
> > +	ret =3D sysfs_emit(buf, "%s", ziirave_reasons[w_priv->reset_reason]);=
 =20
>=20
> All of these formats should probably end with a newline
> and the ZIIRAVE_<FOO>_VERSION_FMT defines are to me unnecessary.
>=20

I'll send a follow-on patch for that.

...Juerg

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