Add a strtobool function matching semantics of existing in kernel equivalents

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/include/linux/string.h b/include/linux/string.h
index a716ee2a8adb8df5cf545a9e9638e733fba777e7..a176db2f2c854755c360202358a227b4f42435d3 100644 (file)
--- 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 f71bead1be3efaf5694cbbe1df1d59edb18b74ae..01fad9b203e192eb8a3299d669c29e11e4cf2e04 100644 (file)
--- 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)
+{
+       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