[ovs-dev] [threads 14/23] uuid: Make uuid_generate() thread-safe.
Ben Pfaff
blp at nicira.com
Thu Jul 18 23:15:27 UTC 2013
Signed-off-by: Ben Pfaff <blp at nicira.com>
---
lib/uuid.c | 21 +++++++++++++--------
1 files changed, 13 insertions(+), 8 deletions(-)
diff --git a/lib/uuid.c b/lib/uuid.c
index cfaf0c5..7b03fe0 100644
--- a/lib/uuid.c
+++ b/lib/uuid.c
@@ -1,4 +1,4 @@
-/* Copyright (c) 2008, 2009, 2010, 2011 Nicira, Inc.
+/* Copyright (c) 2008, 2009, 2010, 2011, 2013 Nicira, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
@@ -26,6 +26,7 @@
#include "aes128.h"
#include "entropy.h"
+#include "ovs-thread.h"
#include "sha1.h"
#include "timeval.h"
#include "util.h"
@@ -49,11 +50,8 @@ static void do_init(void);
void
uuid_init(void)
{
- static bool inited;
- if (!inited) {
- do_init();
- inited = true;
- }
+ static pthread_once_t once = PTHREAD_ONCE_INIT;
+ pthread_once(&once, do_init);
}
/* Generates a new random UUID in 'uuid'.
@@ -83,15 +81,22 @@ uuid_init(void)
void
uuid_generate(struct uuid *uuid)
{
+ static pthread_mutex_t mutex = PTHREAD_ADAPTIVE_MUTEX_INITIALIZER;
+ uint64_t copy[2];
+
uuid_init();
- /* Increment the counter. */
+ /* Copy out the counter's current value, then increment it. */
+ xpthread_mutex_lock(&mutex);
+ copy[0] = counter[0];
+ copy[1] = counter[1];
if (++counter[1] == 0) {
counter[0]++;
}
+ xpthread_mutex_unlock(&mutex);
/* AES output is exactly 16 bytes, so we encrypt directly into 'uuid'. */
- aes128_encrypt(&key, counter, uuid);
+ aes128_encrypt(&key, copy, uuid);
/* Set bits to indicate a random UUID. See RFC 4122 section 4.4. */
uuid->parts[2] &= ~0xc0000000;
--
1.7.2.5
More information about the dev
mailing list