Messages in this thread |  | | Date | Tue, 21 Aug 2018 15:57:34 +0200 | From | Greg Kroah-Hartman <> | Subject | Re: [RFC][PATCH] lib/string: introduce sysfs_strncpy() and sysfs_strlcpy() |
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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
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