[U-Boot] [PATCH V2 2/3] lib: uuid: add functions to generate UUID version 4

[Przemyslaw Marczak]

This patch adds support to generate UUID (Universally Unique Identifier)
in version 4 based on RFC4122, which is randomly.

Source: https://www.ietf.org/rfc/rfc4122.txt

Changes:
- add new config: CONFIG_RANDOM_UUID: compile uuid.c and rand.c

Update files:
- include/common.h
- lib/Makefile
- lib/uuid.c

lib/uuid.c:
- add gen_rand_uuid() - this function writes 16 bytes len binary representation
  UUID v4 to address given by user.

- add gen_rand_uuid_str() - this function writes 37 bytes len hexadecimal
  ASCII string representation of 16 bytes binary UUID to address given by user.

Signed-off-by: Przemyslaw Marczak <p.marczak at samsung.com>
cc: Stephen Warren <swarren at nvidia.com>
cc: trini at ti.com

---
Changes v2:
- put uuid generation changes in a separate commit
- get_uuid_str() - change name to gen_rand_uuid_str()
- add new function: gen_rand_uuid()
- remove unnecessary '\0' at the end of uuid string
- drop unnecessary error checking
- functions now takes pointers to allocated memory instead of alloc it itself
- add new config option: CONFIG_RANDOM_UUID
---
 include/common.h |    5 +++-
 lib/Makefile     |    4 ++-
 lib/uuid.c       |   81 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 88 insertions(+), 2 deletions(-)

diff --git a/include/common.h b/include/common.h
index 32377ad..20e9ae6 100644
--- a/include/common.h
+++ b/include/common.h
@@ -815,6 +815,8 @@ void	udelay        (unsigned long);
 void mdelay(unsigned long);
 
 /* lib/uuid.c */
+void gen_rand_uuid(unsigned char *uuid_bin);
+void gen_rand_uuid_str(char *uuid_str);
 void uuid_bin_to_str(unsigned char *uuid, char *str);
 int uuid_str_to_bin(char *uuid, unsigned char *out);
 int uuid_str_valid(const char *uuid);
@@ -831,7 +833,8 @@ char *	strmhz(char *buf, unsigned long hz);
 /* lib/rand.c */
 #if defined(CONFIG_RANDOM_MACADDR) || \
 	defined(CONFIG_BOOTP_RANDOM_DELAY) || \
-	defined(CONFIG_CMD_LINK_LOCAL)
+	defined(CONFIG_CMD_LINK_LOCAL) || \
+	defined(CONFIG_RANDOM_UUID)
 #define RAND_MAX -1U
 void srand(unsigned int seed);
 unsigned int rand(void);
diff --git a/lib/Makefile b/lib/Makefile
index 70962b2..64a430f 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -59,10 +59,12 @@ obj-y += linux_string.o
 obj-$(CONFIG_REGEX) += slre.o
 obj-y += string.o
 obj-y += time.o
+obj-y += vsprintf.o
 obj-$(CONFIG_TRACE) += trace.o
 obj-$(CONFIG_BOOTP_PXE) += uuid.o
 obj-$(CONFIG_PARTITION_UUIDS) += uuid.o
-obj-y += vsprintf.o
+obj-$(CONFIG_RANDOM_UUID) += uuid.o
+obj-$(CONFIG_RANDOM_UUID) += rand.o
 obj-$(CONFIG_RANDOM_MACADDR) += rand.o
 obj-$(CONFIG_BOOTP_RANDOM_DELAY) += rand.o
 obj-$(CONFIG_CMD_LINK_LOCAL) += rand.o
diff --git a/lib/uuid.c b/lib/uuid.c
index 803bdcd..c0218ba 100644
--- a/lib/uuid.c
+++ b/lib/uuid.c
@@ -7,6 +7,29 @@
 #include <linux/ctype.h>
 #include <errno.h>
 #include <common.h>
+#include <part_efi.h>
+#include <malloc.h>
+
+#define UUID_STR_LEN			36
+#define UUID_STR_BYTE_LEN		37
+#define UUID_BIN_BYTE_LEN		16
+
+#define UUID_VERSION_CLEAR_BITS		0x0fff
+#define UUID_VERSION_SHIFT		12
+#define UUID_VERSION			0x4
+
+#define UUID_VARIANT_CLEAR_BITS		0x3f
+#define UUID_VARIANT_SHIFT		7
+#define UUID_VARIANT			0x1
+
+struct uuid {
+	unsigned int time_low;
+	unsigned short time_mid;
+	unsigned short time_hi_and_version;
+	unsigned char clock_seq_hi_and_reserved;
+	unsigned char clock_seq_low;
+	unsigned char node[6];
+};
 
 /*
  * This is what a UUID string looks like.
@@ -94,3 +117,61 @@ void uuid_bin_to_str(unsigned char *uuid, char *str)
 		}
 	}
 }
+
+/*
+ * gen_rand_uuid() - this function generates 16 bytes len UUID V4 (randomly)
+ *                   and stores it at a given pointer.
+ *
+ * Layout of UUID Version 4:
+ * timestamp - 60-bit: time_low, time_mid, time_hi_and_version
+ * version   - 4 bit (bit 4 through 7 of the time_hi_and_version)
+ * clock seq - 14 bit: clock_seq_hi_and_reserved, clock_seq_low
+ * variant:  - bit 6 and 7 of clock_seq_hi_and_reserved
+ * node      - 48 bit
+ * In this version all fields beside 4 bit version are randomly generated.
+ * source: https://www.ietf.org/rfc/rfc4122.txt
+ *
+ * @param uuid_bin pointer to 16 bytes len array
+*/
+void gen_rand_uuid(unsigned char *uuid_bin)
+{
+	struct uuid *uuid = (struct uuid *)uuid_bin;
+	unsigned int *ptr = (unsigned int *)uuid_bin;
+	int i;
+
+	if (!uuid_bin)
+		return;
+
+	memset(uuid_bin, 0x0, sizeof(struct uuid));
+
+	/* Set all fields randomly */
+	for (i = 0; i < sizeof(struct uuid) / sizeof(*ptr); i++)
+		*(ptr + i) = rand();
+
+	/* Set V4 format */
+	uuid->time_hi_and_version &= UUID_VERSION_CLEAR_BITS;
+	uuid->time_hi_and_version |= UUID_VERSION << UUID_VERSION_SHIFT;
+
+	uuid->clock_seq_hi_and_reserved &= UUID_VARIANT_CLEAR_BITS;
+	uuid->clock_seq_hi_and_reserved |= UUID_VARIANT << UUID_VARIANT_SHIFT;
+}
+
+/*
+ * gen_rand_uuid_str() - this function generates UUID v4 (randomly)
+ * into 36 character hexadecimal ASCII string representation of a 128-bit
+ * (16 octets) UUID (Universally Unique Identifier) version 4 based on RFC4122
+ * and stores it at a given pointer.
+ *
+ * @param uuid_str pointer to 37 bytes len array
+ */
+void gen_rand_uuid_str(char *uuid_str)
+{
+	unsigned char uuid_bin[UUID_BIN_BYTE_LEN];
+
+	if (!uuid_str)
+		return;
+
+	gen_rand_uuid(uuid_bin);
+
+	uuid_bin_to_str(uuid_bin, uuid_str);
+}
-- 
1.7.9.5