From 09bd9aa412d67cfd326b60ade1510f1d4c6344a9 Mon Sep 17 00:00:00 2001
From: Christopher Faulet <cfaulet@haproxy.com>
Date: Tue, 17 Sep 2019 15:07:02 +0200
Subject: [PATCH] MINOR: spoe: Improve generation of the engine-id

Use the same algo than the sample fetch uuid(). This one was added recently. So
it is better to use the same way to generate UUIDs.

This patch may be backported to older versions.
---
 src/flt_spoe.c | 39 +++++++++++++++++++++------------------
 1 file changed, 21 insertions(+), 18 deletions(-)

diff --git a/src/flt_spoe.c b/src/flt_spoe.c
index f0047d4d9..114ecf39b 100644
--- a/src/flt_spoe.c
+++ b/src/flt_spoe.c
@@ -256,30 +256,32 @@ static const char *spoe_appctx_state_str[SPOE_APPCTX_ST_END+1] = {
 static char *
 generate_pseudo_uuid()
 {
-	static int init = 0;
-
-	const char uuid_fmt[] = "xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx";
-	const char uuid_chr[] = "0123456789ABCDEF-";
 	char *uuid;
-	int i;
+	uint32_t rnd[4] = { 0, 0, 0, 0 };
+	uint64_t last = 0;
+	int byte = 0;
+	uint8_t bits = 0;
+	unsigned int rand_max_bits = my_flsl(RAND_MAX);
 
-	if ((uuid = calloc(1, sizeof(uuid_fmt))) == NULL)
+	if ((uuid = calloc(1, 37)) == NULL)
 		return NULL;
 
-	if (!init) {
-		srand(now_ms * pid);
-		init = 1;
-	}
-
-	for (i = 0; i < sizeof(uuid_fmt)-1; i++) {
-		int r = rand () % 16;
-
-		switch (uuid_fmt[i]) {
-			case 'x' : uuid[i] = uuid_chr[r]; break;
-			case 'y' : uuid[i] = uuid_chr[(r & 0x03) | 0x08]; break;
-			default  : uuid[i] = uuid_fmt[i]; break;
+	while (byte < 4) {
+		while (bits < 32) {
+			last |= (uint64_t)random() << bits;
+			bits += rand_max_bits;
 		}
+		rnd[byte++] = last;
+		last >>= 32u;
+		bits  -= 32;
 	}
+	snprintf(uuid, 36, "%8.8x-%4.4x-%4.4x-%4.4x-%12.12llx",
+			     rnd[0],
+			     rnd[1] & 0xFFFF,
+			     ((rnd[1] >> 16u) & 0xFFF) | 0x4000,  // highest 4 bits indicate the uuid version
+			     (rnd[2] & 0x3FFF) | 0x8000,  // the highest 2 bits indicate the UUID variant (10),
+			     (long long)((rnd[2] >> 14u) | ((uint64_t) rnd[3] << 18u)) & 0xFFFFFFFFFFFFull
+			);
 	return uuid;
 }
 
@@ -3120,6 +3122,7 @@ spoe_init_per_thread(struct proxy *p, struct flt_conf *fconf)
 	struct spoe_agent *agent = conf->agent;
 
 	if (agent->engine_id == NULL) {
+		srandom(now_ms * pid);
 		agent->engine_id = generate_pseudo_uuid();
 		if (agent->engine_id == NULL)
 			return -1;