From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>,
Andrew Morton <akpm@linux-foundation.org>,
Arnd Bergmann <arnd@arndb.de>, Martin Wilck <mwilck@suse.com>,
Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
linux-kernel@vger.kernel.org,
Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Subject: Re: [RFC][PATCH] lib/string: introduce sysfs_strncpy() and sysfs_strlcpy()
Date: Tue, 21 Aug 2018 15:57:34 +0200 [thread overview]
Message-ID: <20180821135734.GA19916@kroah.com> (raw)
In-Reply-To: <20180821095055.GA400@jagdpanzerIV>
On Tue, Aug 21, 2018 at 06:50:55PM +0900, Sergey Senozhatsky wrote:
> Hi Rasmus,
>
> On (08/21/18 09:59), Rasmus Villemoes wrote:
> > > +char *sysfs_strncpy(char *dest, const char *src, size_t count)
> > > +{
> > > + char *c;
> > > +
> > > + strncpy(dest, skip_spaces(src), count);
> >
> > I'd like to see where and how you'd use this, but I'm very skeptical of
> > count being used both for the size of the dest buffer as well as an
> > essentially random argument to strncpy - if count is also the maximum
> > number of bytes to read from the src, you'd need to take the
> > skip_spaces() into account, because there are not count bytes left after
> > that...
> > And if src is not necessarily nul-terminated, skip_spaces() by
> > itself is wrong.
>
> I think that sysfs input is always properly NULL-terminated. It may or
> may not contain \n, but \0 is expected to be there. Am I wrong?
sysfs data is always null terminated.
What exactly are you trying to do here? If a user sends you crappy data
in a sysfs file (like leading or trailing whitespace), well, you can
always just error out, no problem. You can be very strict in the
SINGLE_VALUE that you accept in your sysfs file. And yes, sysfs files
are single values, if you want to do more than that, you need to use
something else, so I really do not understand what problem you are
trying to solve here.
Please always post a user of your new api when you make stuff like this
otherwise we do not know how it is used, or even why you are adding it.
thanks,
greg k-h
next prev parent reply other threads:[~2018-08-21 13:57 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-21 6:24 [RFC][PATCH] lib/string: introduce sysfs_strncpy() and sysfs_strlcpy() Sergey Senozhatsky
2018-08-21 7:59 ` Rasmus Villemoes
2018-08-21 9:50 ` Sergey Senozhatsky
2018-08-21 9:54 ` Sergey Senozhatsky
2018-08-21 11:44 ` Sergey Senozhatsky
2018-08-21 12:00 ` Andy Shevchenko
2018-08-22 0:32 ` Sergey Senozhatsky
2018-08-21 12:43 ` Rasmus Villemoes
2018-08-22 5:13 ` Sergey Senozhatsky
2018-08-21 13:57 ` Greg Kroah-Hartman [this message]
2018-08-22 4:58 ` Sergey Senozhatsky
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