From: Thomas Weißschuh <thomas@t-8ch.de>
Date: Tue, 21 May 2024 16:44:19 +0000 (+0200)
Subject: libuuid: construct UUIDv7 without "struct uuid"
X-Git-Tag: v2.42-start~325^2
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=5175604b48b7dea9b60fe5f2ee440891032d522f;p=thirdparty%2Futil-linux.git

libuuid: construct UUIDv7 without "struct uuid"

The layout of "struct uuid" is specific to UUIDv1.
Using it for UUIDv7 makes the logic complicated and confuses Coverity.

Signed-off-by: Thomas Weißschuh <thomas@t-8ch.de>
---

diff --git a/libuuid/src/gen_uuid.c b/libuuid/src/gen_uuid.c
index 13f6651c5..419d39da1 100644
--- a/libuuid/src/gen_uuid.c
+++ b/libuuid/src/gen_uuid.c
@@ -694,21 +694,20 @@ void uuid_generate_time_v6(uuid_t out)
 void uuid_generate_time_v7(uuid_t out)
 {
 	struct timeval tv;
-	struct uuid uu;
 	uint64_t ms;
 
 	gettimeofday(&tv, NULL);
 
 	ms = tv.tv_sec * MSEC_PER_SEC + tv.tv_usec / USEC_PER_MSEC;
 
-	uu.time_low = ms >> 16;
-	uu.time_mid = ms;
-
-	ul_random_get_bytes(&uu.time_hi_and_version, 10);
-	uu.time_hi_and_version = (uu.time_hi_and_version & 0x0FFF) | (7 << 12);
-	uu.clock_seq = (uu.clock_seq & 0x3FFF) | 0x8000;
-
-	uuid_pack(&uu, out);
+	out[0] = ms >> 40;
+	out[1] = ms >> 32;
+	out[2] = ms >> 24;
+	out[3] = ms >> 16;
+	out[4] = ms >>  8;
+	out[5] = ms >>  0;
+	ul_random_get_bytes(out + 6, 10);
+	__uuid_set_variant_and_version(out, UUID_TYPE_DCE_TIME_V7);
 }