Re: [PATCH v4 2/8] lib: add "on" and "off" to strtobool
From: Joe Perches
Date: Tue Jan 19 2016 - 21:09:54 EST
On Tue, 2016-01-19 at 10:08 -0800, Kees Cook wrote:
> Several places in the kernel expect to use "on" and "off" for their
> boolean signifiers, so add them to strtobool.
Several places in the kernel use a char address like
fs/cifs/cifs_debug.c
char c;
...
if (strtobool(&c, ...))
Using s[1] might cause problems for those uses.
> diff --git a/lib/string.c b/lib/string.c
[]
> @@ -635,12 +635,15 @@ EXPORT_SYMBOL(sysfs_streq);
> * @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.
> + * 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.
> */
> int strtobool(const char *s, bool *res)
> {
> + if (!s)
> + return -EINVAL;
> +
> switch (s[0]) {
> case 'y':
> case 'Y':
> @@ -652,6 +655,21 @@ int strtobool(const char *s, bool *res)
> case '0':
> *res = false;
> break;
> + case 'o':
> + case 'O':
> + switch (s[1]) {
> + case 'n':
> + case 'N':
> + *res = true;
> + break;
> + case 'f':
> + case 'F':
Perhaps
switch (tolower(s[1])) {
is more readable
> + *res = false;
> + break;
> + default:
> + return -EINVAL;
> + }
> + break;
or maybe /* fallthrough */
> default:
> return -EINVAL;
> }