[PATCH 1/2] lib: fwts_guid: Add fwts_guid_str_to_buf to convert string back to a GUID

[Colin King]

From: Colin Ian King <colin.king at canonical.com>

We need to convert GUIDs in ASCII strings back to a 16 byte GUID for
some of the UEFI variable GUID string handling.

Signed-off-by: Colin Ian King <colin.king at canonical.com>
---
 src/lib/include/fwts_guid.h |    1 +
 src/lib/src/fwts_guid.c     |   14 ++++++++++++++
 2 files changed, 15 insertions(+)

diff --git a/src/lib/include/fwts_guid.h b/src/lib/include/fwts_guid.h
index d836948..ba5ee6c 100644
--- a/src/lib/include/fwts_guid.h
+++ b/src/lib/include/fwts_guid.h
@@ -24,5 +24,6 @@
 #include <stdint.h>
 
 void fwts_guid_buf_to_str(uint8_t *guid, char *guid_str, size_t guid_str_len);
+void fwts_guid_str_to_buf(const char *guid_str, uint8_t *guid, size_t guid_len);
 
 #endif
diff --git a/src/lib/src/fwts_guid.c b/src/lib/src/fwts_guid.c
index 510cb25..b4e9b07 100644
--- a/src/lib/src/fwts_guid.c
+++ b/src/lib/src/fwts_guid.c
@@ -33,3 +33,17 @@ void fwts_guid_buf_to_str(uint8_t *guid, char *guid_str, size_t guid_str_len)
 			guid[3], guid[2], guid[1], guid[0], guid[5], guid[4], guid[7], guid[6],
 			guid[8], guid[9], guid[10], guid[11], guid[12], guid[13], guid[14], guid[15]);
 }
+
+/*
+ *  fwts_guid_str_to_buf()
+ *	convert a GUID string back to a 16 byte GUID
+ *	guid needs to be at least 16 chars long
+ */
+void fwts_guid_str_to_buf(const char *guid_str, uint8_t *guid, size_t guid_len)
+{
+	if (guid && guid_len >= 16) {
+		sscanf(guid_str, "%2hhx%2hhx%2hhx%2hhx-%2hhx%2hhx-%2hhx%2hhx-%2hhx%2hhx-%2hhx%2hhx%2hhx%2hhx%2hhx%2hhx",
+			&guid[3], &guid[2], &guid[1], &guid[0], &guid[5], &guid[4], &guid[7], &guid[6],
+			&guid[8], &guid[9], &guid[10], &guid[11], &guid[12], &guid[13], &guid[14], &guid[15]);
+	}
+}
-- 
1.7.10.4