Re: [PATCH] watchdog: Use sysfs_emit() and sysfs_emit_at() in "show" functions

[Juerg Haefliger]

On Wed, 12 May 2021 21:48:37 -0700
Joe Perches <joe@xxxxxxxxxxx> 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.  
> []
> > 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.
> 

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

...Juerg

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