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Message-ID: <f2e616645f311ccaf6e0acb996f8c4360a0480ec.camel@perches.com>
Subject: Re: [PATCH] watchdog: Use sysfs_emit() and sysfs_emit_at() in
 "show" functions
From:   Joe Perches <joe@perches.com>
To:     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
Cc:     andrew@aj.id.au, linux-kernel@vger.kernel.org,
        Juerg Haefliger <juergh@canonical.com>
Date:   Wed, 12 May 2021 21:48:37 -0700
In-Reply-To: <20210511061812.480172-1-juergh@canonical.com>
References: <20210511061812.480172-1-juergh@canonical.com>
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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.
[]
> diff --git a/drivers/watchdog/ziirave_wdt.c b/drivers/watchdog/ziirave_wdt.c
[]
> @@ -445,8 +445,9 @@ static ssize_t ziirave_wdt_sysfs_show_firm(struct device *dev,
> ?	if (ret)
> ?		return ret;
> ?
> 
> -	ret = sprintf(buf, ZIIRAVE_FW_VERSION_FMT, w_priv->firmware_rev.major,
> -		      w_priv->firmware_rev.minor);
> +	ret = sysfs_emit(buf, ZIIRAVE_FW_VERSION_FMT,
> +			 w_priv->firmware_rev.major,
> +			 w_priv->firmware_rev.minor);
> ?
> 
> ?	mutex_unlock(&w_priv->sysfs_mutex);
> ?
> 
> @@ -468,8 +469,9 @@ static ssize_t ziirave_wdt_sysfs_show_boot(struct device *dev,
> ?	if (ret)
> ?		return ret;
> ?
> 
> -	ret = sprintf(buf, ZIIRAVE_BL_VERSION_FMT, w_priv->bootloader_rev.major,
> -		      w_priv->bootloader_rev.minor);
> +	ret = sysfs_emit(buf, ZIIRAVE_BL_VERSION_FMT,
> +			 w_priv->bootloader_rev.major,
> +			 w_priv->bootloader_rev.minor);
> ?
> 
> ?	mutex_unlock(&w_priv->sysfs_mutex);
> ?
> 
> @@ -491,7 +493,7 @@ static ssize_t ziirave_wdt_sysfs_show_reason(struct device *dev,
> ?	if (ret)
> ?		return ret;
> ?
> 
> -	ret = sprintf(buf, "%s", ziirave_reasons[w_priv->reset_reason]);
> +	ret = sysfs_emit(buf, "%s", ziirave_reasons[w_priv->reset_reason]);

All of these formats should probably end with a newline
and the ZIIRAVE_<FOO>_VERSION_FMT defines are to me unnecessary.