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

[Ryan Mallon <ryan@bluewatersys.com>]

On 04/19/2011 11:43 PM, Jonathan Cameron wrote:
> This is a rename of the usr_strtobool proposal, which was a renamed,
> relocated and fixed version of previous kstrtobool RFC
> 
> Signed-off-by: Jonathan Cameron <jic23@cam.ac.uk>
> ---
>  include/linux/string.h |    1 +
>  lib/string.c           |   29 +++++++++++++++++++++++++++++
>  2 files changed, 30 insertions(+), 0 deletions(-)
> 
> diff --git a/include/linux/string.h b/include/linux/string.h
> index a716ee2..a176db2 100644
> --- a/include/linux/string.h
> +++ b/include/linux/string.h
> @@ -123,6 +123,7 @@ extern char **argv_split(gfp_t gfp, const char *str, int *argcp);
>  extern void argv_free(char **argv);
>  
>  extern bool sysfs_streq(const char *s1, const char *s2);
> +extern int strtobool(const char *s, bool *res);
>  
>  #ifdef CONFIG_BINARY_PRINTF
>  int vbin_printf(u32 *bin_buf, size_t size, const char *fmt, va_list args);
> diff --git a/lib/string.c b/lib/string.c
> index f71bead..01fad9b 100644
> --- a/lib/string.c
> +++ b/lib/string.c
> @@ -535,6 +535,35 @@ bool sysfs_streq(const char *s1, const char *s2)
>  }
>  EXPORT_SYMBOL(sysfs_streq);
>  
> +/**
> + * strtobool - convert common user inputs into boolean values
> + * @s: input string
> + * @res: result
> + *
> + * This routine returns 0 iff the first character is one of 'Yy1Nn0'.
> + * Otherwise it will return -EINVAL.  Value pointed to by res is
> + * updated upon finding a match.
> + */
> +int strtobool(const char *s, bool *res)
> +{

Might be worth doing:

	if (!s)
		return -EINVAL;

here to avoid blowing up if we get passed a NULL string.

~Ryan

> +	switch (s[0]) {
> +	case 'y':
> +	case 'Y':
> +	case '1':
> +		*res = true;
> +		break;
> +	case 'n':
> +	case 'N':
> +	case '0':
> +		*res = false;
> +		break;
> +	default:
> +		return -EINVAL;
> +	}
> +	return 0;
> +}
> +EXPORT_SYMBOL(strtobool);
> +
>  #ifndef __HAVE_ARCH_MEMSET
>  /**
>   * memset - Fill a region of memory with the given value


-- 
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