buildroot/package/util-linux/0005-libuuid-support-non-cached-scenarios-when-lpthread-i.patch

From eecaa2c0dda817eba2d493f6ddb42c39cf789fc2 Mon Sep 17 00:00:00 2001
From: Karel Zak <kzak@redhat.com>
Date: Mon, 27 Jan 2025 14:28:36 +0100
Subject: [PATCH] libuuid: support non-cached scenarios (when -lpthread is
 unavailable)

This patch makes the dependence on pthread optional for libuuid. In
certain cases, such as Buildroot Linux, uClibc-ng, and very low
resource systems, libpthread may be unavailable.

If libuuid is compiled without pthread, it will not use a local cache
and will instead request a UUID from uuidd for each call. This may
result in less efficient performance, but the UUIDs generated will
still be unique and reliable.

On minimalistic systems, it is highly likely that uuidd will not be
installed, making this change important for portability and robust
code.

Upstream: https://github.com/util-linux/util-linux/pull/3383
Addresses: https://github.com/util-linux/util-linux/pull/3375
Signed-off-by: Karel Zak <kzak@redhat.com>
Signed-off-by: Julien Olivain <ju.o@free.fr>
---
 libuuid/src/gen_uuid.c | 18 +++++++++++++++---
 1 file changed, 15 insertions(+), 3 deletions(-)

diff --git a/libuuid/src/gen_uuid.c b/libuuid/src/gen_uuid.c
index 69712267f..1ed82b46b 100644
--- a/libuuid/src/gen_uuid.c
+++ b/libuuid/src/gen_uuid.c
@@ -80,7 +80,10 @@
 #if defined(__linux__) && defined(HAVE_SYS_SYSCALL_H)
 #include <sys/syscall.h>
 #endif
-#include <pthread.h>
+#ifdef HAVE_LIBPTHREAD
+# include <pthread.h>
+#endif
+
 #include <signal.h>
 
 #include "all-io.h"
@@ -580,8 +583,7 @@ int __uuid_generate_time_cont(uuid_t out, int *num, uint32_t cont_offset)
  * If neither of these is possible (e.g. because of insufficient permissions), it generates
  * the UUID anyway, but returns -1. Otherwise, returns 0.
  */
-
-/* thread local cache for uuidd based requests */
+#ifdef HAVE_LIBPTHREAD
 THREAD_LOCAL struct {
 	int		num;
 	int		cache_size;
@@ -597,8 +599,10 @@ static void reset_uuidd_cache(void)
 	memset(&uuidd_cache, 0, sizeof(uuidd_cache));
 	uuidd_cache.cache_size = CS_MIN;
 }
+#endif /* HAVE_LIBPTHREAD */
 
 static int uuid_generate_time_generic(uuid_t out) {
+#ifdef HAVE_LIBPTHREAD
 	static volatile sig_atomic_t atfork_registered;
 	time_t	now;
 
@@ -651,6 +655,14 @@ static int uuid_generate_time_generic(uuid_t out) {
 		return 0;
 	}
 
+#else /* !HAVE_LIBPTHREAD */
+	{
+		int num = 1;
+		if (get_uuid_via_daemon(UUIDD_OP_TIME_UUID, out, &num) == 0)
+			return 0;
+	}
+#endif /* HAVE_LIBPTHREAD */
+
 	return __uuid_generate_time(out, NULL);
 }
 
-- 
2.48.1