[PATCH v2 109/113] lib: uuid: implement uuid/guid_parse

[Ahmad Fatoum]

We opencode this at least once in EFI code, so import the Linux
definition and start using that instead.

Signed-off-by: Ahmad Fatoum <a.fatoum at pengutronix.de>
---
 lib/uuid.c | 63 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 63 insertions(+)

diff --git a/lib/uuid.c b/lib/uuid.c
index 60a651e3301a..1c134bfb4b15 100644
--- a/lib/uuid.c
+++ b/lib/uuid.c
@@ -9,6 +9,7 @@
 #include <linux/uuid.h>
 #include <module.h>
 #include <stdlib.h>
+#include <linux/ctype.h>
 #include <linux/export.h>
 
 const guid_t guid_null;
@@ -16,6 +17,9 @@ EXPORT_SYMBOL(guid_null);
 const uuid_t uuid_null;
 EXPORT_SYMBOL(uuid_null);
 
+const u8 guid_index[16] = {3,2,1,0,5,4,7,6,8,9,10,11,12,13,14,15};
+const u8 uuid_index[16] = {0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15};
+
 /**
  * generate_random_uuid - generate a random UUID
  * @uuid: where to put the generated UUID
@@ -44,3 +48,62 @@ void generate_random_guid(unsigned char guid[16])
 	guid[8] = (guid[8] & 0x3F) | 0x80;
 }
 EXPORT_SYMBOL(generate_random_guid);
+
+/**
+ * uuid_is_valid - checks if a UUID string is 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: true if input is valid UUID string.
+ */
+bool uuid_is_valid(const char *uuid)
+{
+	unsigned int i;
+
+	for (i = 0; i < UUID_STRING_LEN; i++) {
+		if (i == 8 || i == 13 || i == 18 || i == 23) {
+			if (uuid[i] != '-')
+				return false;
+		} else if (!isxdigit(uuid[i])) {
+			return false;
+		}
+	}
+
+	return true;
+}
+EXPORT_SYMBOL(uuid_is_valid);
+
+static int __uuid_parse(const char *uuid, __u8 b[16], const u8 ei[16])
+{
+	static const u8 si[16] = {0,2,4,6,9,11,14,16,19,21,24,26,28,30,32,34};
+	unsigned int i;
+
+	if (!uuid_is_valid(uuid))
+		return -EINVAL;
+
+	for (i = 0; i < 16; i++) {
+		int hi = hex_to_bin(uuid[si[i] + 0]);
+		int lo = hex_to_bin(uuid[si[i] + 1]);
+
+		b[ei[i]] = (hi << 4) | lo;
+	}
+
+	return 0;
+}
+
+int guid_parse(const char *uuid, guid_t *u)
+{
+	return __uuid_parse(uuid, u->b, guid_index);
+}
+EXPORT_SYMBOL(guid_parse);
+
+int uuid_parse(const char *uuid, uuid_t *u)
+{
+	return __uuid_parse(uuid, u->b, uuid_index);
+}
+EXPORT_SYMBOL(uuid_parse);
-- 
2.39.2