linux-kernel - Re: [PATCH v2 3/8] lib/uuid: introduce few more generic helpers for UUID

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Date:	Tue, 5 Apr 2016 10:48:44 +1000
From:	Stephen Rothwell <sfr@...b.auug.org.au>
To:	Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Cc:	Andrew Morton <akpm@...ux-foundation.org>,
	Arnd Bergmann <arnd@...db.de>, "Theodore Ts'o" <tytso@....edu>,
	Matt Fleming <matt@...eblueprint.co.uk>,
	Rasmus Villemoes <linux@...musvillemoes.dk>,
	linux-kernel@...r.kernel.org, linux-efi@...r.kernel.org,
	linux-api@...r.kernel.org
Subject: Re: [PATCH v2 3/8] lib/uuid: introduce few more generic helpers for
 UUID

Hi Andy,

On Mon, 4 Apr 2016 16:40:29 -0700 Andrew Morton <akpm@...ux-foundation.org> wrote:
>
> On Mon,  4 Apr 2016 16:30:05 +0300 Andy Shevchenko <andriy.shevchenko@...ux.intel.com> wrote:
> 
> > There are new helpers in this patch:
> > 
> > uuid_is_valid		checks if a UUID is valid
> > uuid_be_to_bin		converts from string to binary (big endian)
> > uuid_le_to_bin		converts from string to binary (little endian)
> 	> 
> > They will be used in future, i.e. in the following patches in the series.
> > 
> > This also moves indices arrays to lib/uuid.c to be shared accross modules.
> > 
> > ...
> >
> > --- a/include/linux/uuid.h
> > +++ b/include/linux/uuid.h  
> 
> Nit:
> 
> > +/**
> > +  * uuid_is_valid - checks if UUID string valid
> > +  * @uuid:	UUID string to check
> > +  *
> > +  * Description:
> > +  * It checks if the UUID string is following the format:
> > +  *	xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx
> > +  * where x is a hex digit.
> > +  *
> > +  * Return: 0 on success, %-EINVAL otherwise.
> > +  */
> > +int uuid_is_valid(const char *uuid)
> > +{
> > +	unsigned int i;
> > +
> > +	if (strnlen(uuid, UUID_STRING_LEN) < UUID_STRING_LEN)
> > +		return -EINVAL;
> > +
> > +	for (i = 0; i < UUID_STRING_LEN; i++) {
> > +		if (i == 8 || i == 13 || i == 18 || i == 23) {
> > +			if (uuid[i] != '-')
> > +				return -EINVAL;
> > +		} else if (!isxdigit(uuid[i])) {
> > +			return -EINVAL;
> > +		}
> > +	}  
> 
> Could add
> 
> 	if (uuid[i])
> 		return -EINVAL;
> 
> here and lose the additional pass across the input (strlen).

also, why is this not a bool function?

-- 
Cheers,
Stephen Rothwell