linux-kernel - Re: [PATCH V2] sysfs: Add sysfs_emit and sysfs_emit

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Message-ID: <20200907133604.GA2779041@kroah.com>
Date:   Mon, 7 Sep 2020 15:36:04 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     Joe Perches <joe@...ches.com>
Cc:     "Rafael J. Wysocki" <rafael@...nel.org>,
        Kees Cook <keescook@...omium.org>,
        "Gustavo A . R . Silva" <gustavoars@...nel.org>,
        Denis Efremov <efremov@...ux.com>,
        Julia Lawall <julia.lawall@...ia.fr>,
        Alex Dewar <alex.dewar90@...il.com>,
        Jonathan Corbet <corbet@....net>, linux-doc@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH V2] sysfs: Add sysfs_emit and sysfs_emit_at to format
 sysfs output

On Sat, Aug 29, 2020 at 05:43:58PM -0700, Joe Perches wrote:
> On Sat, 2020-08-29 at 16:48 -0700, Joe Perches wrote:
> > Output defects can exist in sysfs content using sprintf and snprintf.
> > 
> > sprintf does not know the PAGE_SIZE maximum of the temporary buffer
> > used for outputting sysfs content and it's possible to overrun the
> > PAGE_SIZE buffer length.
> > 
> > Add a generic sysfs_emit function that knows that the size of the
> > temporary buffer and ensures that no overrun is done.
> > 
> > Add a generic sysfs_emit_at function that can be used in multiple
> > call situations that also ensures that no overrun is done.
> 
> This preliminary coccinelle script converts ~5000 instances treewide.
> There are still many remaining instances that could be converted.
> 
> $ git grep -w sysfs_emit -- '*.[ch]'|wc -l
> 4702
> $ git grep -w sysfs_emit_at -- '*.[ch]'|wc -l
> 229

Can you send a patch that would at least convert the driver core code
(drivers/base/*) to use these new helpers so we have an in-tree user
when applying the first patch?

thanks,

greg k-h