Re: [PATCH] lib: Extend kstrtobool() to accept "true"/"false"

From: Rafael J. Wysocki
Date: Fri Jun 26 2020 - 11:49:39 EST


On Fri, Jun 26, 2020 at 12:45 PM Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:
>
> On Fri, Jun 26, 2020 at 12:22:55PM +0200, Peter Zijlstra wrote:
>
> > > This is too lax - it will be enabled for any !0 value. Please accept
> > > only 0 and 1.
> >
> > kstrtobool() ftw
>
> And looking at that, I find it really strange it does not in fact accept
> "true" / "false", so how about this?
>
> ---
> Subject: lib: Extend kstrtobool() to accept "true"/"false"
>
> Extend the strings recognised by kstrtobool() to cover:
>
> - 1/0
> - y/n
> - yes/no (new)
> - t/f (new)
> - true/false (new)
> - on/off
>
> Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>

Reviewed-by: Rafael J. Wysocki <rafael@xxxxxxxxxx>

> ---
> lib/kstrtox.c | 60 ++++++++++++++++++++++++++++++++++++++++++++---------------
> 1 file changed, 45 insertions(+), 15 deletions(-)
>
> diff --git a/lib/kstrtox.c b/lib/kstrtox.c
> index 1006bf70bf74..b8b950325097 100644
> --- a/lib/kstrtox.c
> +++ b/lib/kstrtox.c
> @@ -325,9 +325,17 @@ EXPORT_SYMBOL(kstrtos8);
> * @s: input string
> * @res: result
> *
> - * This routine returns 0 iff the first character is one of 'Yy1Nn0', or
> - * [oO][NnFf] for "on" and "off". Otherwise it will return -EINVAL. Value
> - * pointed to by res is updated upon finding a match.
> + * This return return 0 on success, otherwise it will return -EINVAL.
> + * It will accept (case invariant):
> + *
> + * - 1/0
> + * - y/n
> + * - yes/no
> + * - t/f
> + * - true/false
> + * - on/off
> + *
> + * and set @*res to either true/false respectively.
> */
> int kstrtobool(const char *s, bool *res)
> {
> @@ -335,30 +343,52 @@ int kstrtobool(const char *s, bool *res)
> return -EINVAL;
>
> switch (s[0]) {
> + case 't':
> + case 'T':
> + if (!s[1] || !strcasecmp(s, "true"))
> + goto have_true;
> +
> + break;
> +
> case 'y':
> case 'Y':
> + if (!s[1] || !strcasecmp(s, "yes"))
> + goto have_true;
> +
> + break;
> +
> case '1':
> +have_true:
> *res = true;
> return 0;
> +
> + case 'f':
> + case 'F':
> + if (!s[1] || !strcasecmp(s, "false"))
> + goto have_false;
> +
> + break;
> case 'n':
> case 'N':
> + if (!s[1] || !strcasecmp(s, "no"))
> + goto have_false;
> +
> + break;
> case '0':
> +have_false:
> *res = false;
> return 0;
> +
> case 'o':
> case 'O':
> - switch (s[1]) {
> - case 'n':
> - case 'N':
> - *res = true;
> - return 0;
> - case 'f':
> - case 'F':
> - *res = false;
> - return 0;
> - default:
> - break;
> - }
> + if (!strcasecmp(s, "on"))
> + goto have_true;
> +
> + if (!strcasecmp(s, "off"))
> + goto have_false;
> +
> + break;
> +
> default:
> break;
> }