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

On Mon, 2016-04-04 at 16:40 -0700, Andrew Morton wrote:

On Mon,  4 Apr 2016 16:30:05 +0300 Andy Shevchenko  wrote:

quoted

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)

	> 

quoted

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:

quoted

+/**
+  * 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).

nit2:

Could make this return bool.