Re: [PATCH 1/3] Add a kstrtobool function matching semantics of existing in kernel equivalents.

[Greg KH <greg@kroah.com>]

On Wed, Mar 23, 2011 at 04:15:51PM +0000, Jonathan Cameron wrote:
> On 03/23/11 16:01, Greg KH wrote:
> > On Wed, Mar 23, 2011 at 05:30:11PM +0200, Alexey Dobriyan wrote:
> >> On Wed, Mar 23, 2011 at 3:39 PM, Jonathan Cameron <jic23@cam.ac.uk> wrote:
> >>> +int kstrtobool(const char *s, bool *res)
> >>> +{
> >>> +       switch (s[0]) {
> >>> +       case 'y':
> >>> +       case 'Y':
> >>> +       case '1':
> >>> +               *res = true;
> >>> +       case 'n':
> >>> +       case 'N':
> >>> +       case '0':
> >>> +               *res = false;
> >>> +       default:
> >>> +               return -EINVAL;
> >>> +       }
> >>> +       return 0;
> >>> +}
> >>
> >> sigh... such simple thing and so many bugs
> Yeah, not by best work.
> >>
> >> The only values such function should accept is 0 and 1.
> > 
> > Why?  That's not the way the existing kernel functions that use this
> > work.
> > 
> >> Have you read the rest of kstrto*() code?
> >> Where is newline check?
> There are plenty of nastier cases that get through than a newline
> in the middle of the string (ybobsyouruncle -> 1 nyes->0 :)
> >>
> >> Anyway, I think it's better do not exist.
> > 
> > I think it is, as it's already duplicated in at least 2 different places
> > in the kernel, and probably more.  Once we get this implementation
> > working correctly, we don't need to rewrite it again.
> Perhaps naming it like this is a bad idea.  It manages to imply that it
> has the same level of strict checking which is seen in the other kstrto*
> functions - which is self evidently not true!

Ok, perhaps the name might need to be changed a bit, but the idea is
still good to have.  Please try again.

thanks,

greg k-h