From a41463e31c4e3c231a84c47088e76d39191c4f36 Mon Sep 17 00:00:00 2001
From: Bruce Momjian <bruce@momjian.us>
Date: Mon, 12 Jul 2004 14:11:17 +0000
Subject: [PATCH] win32 doesn't support a static initializer for mutexes, thus
the first user must initialize the lock. The problem are concurrent "first"
users - the pthread_mutex_t initialization must be synchronized. The current
implementation is broken, the attached patches fixes that: mutex_initlock is
a spinlock. If the pthread_mutex_t mutex is not initialized, then the
spinlock is acquired, if the pthread_mutex_t is initialized if it's not yet
initialized and then the spinlock is dropped.
Manfred Spraul
---
src/interfaces/libpq/fe-connect.c | 16 +++++++++++-----
src/interfaces/libpq/fe-secure.c | 16 +++++++++++-----
2 files changed, 22 insertions(+), 10 deletions(-)
diff --git a/src/interfaces/libpq/fe-connect.c b/src/interfaces/libpq/fe-connect.c
index c323c45fc6f..9b60efa3e67 100644
--- a/src/interfaces/libpq/fe-connect.c
+++ b/src/interfaces/libpq/fe-connect.c
@@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/interfaces/libpq/fe-connect.c,v 1.275 2004/06/19 04:22:17 momjian Exp $
+ * $PostgreSQL: pgsql/src/interfaces/libpq/fe-connect.c,v 1.276 2004/07/12 14:11:17 momjian Exp $
*
*-------------------------------------------------------------------------
*/
@@ -3193,10 +3193,16 @@ default_threadlock(int acquire)
#ifndef WIN32
static pthread_mutex_t singlethread_lock = PTHREAD_MUTEX_INITIALIZER;
#else
- static pthread_mutex_t singlethread_lock;
- static long mutex_initialized = 0;
- if (!InterlockedExchange(&mutex_initialized, 1L))
- pthread_mutex_init(&singlethread_lock, NULL);
+ static pthread_mutex_t singlethread_lock = NULL;
+ static long mutex_initlock = 0;
+
+ if (singlethread_lock == NULL) {
+ while(InterlockedExchange(&mutex_initlock, 1) == 1)
+ /* loop, another thread own the lock */ ;
+ if (singlethread_lock == NULL)
+ pthread_mutex_init(&singlethread_lock, NULL);
+ InterlockedExchange(&mutex_initlock,0);
+ }
#endif
if (acquire)
pthread_mutex_lock(&singlethread_lock);
diff --git a/src/interfaces/libpq/fe-secure.c b/src/interfaces/libpq/fe-secure.c
index c827f940e25..ad7897ff7f4 100644
--- a/src/interfaces/libpq/fe-secure.c
+++ b/src/interfaces/libpq/fe-secure.c
@@ -11,7 +11,7 @@
*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/interfaces/libpq/fe-secure.c,v 1.42 2004/06/19 04:22:17 momjian Exp $
+ * $PostgreSQL: pgsql/src/interfaces/libpq/fe-secure.c,v 1.43 2004/07/12 14:11:17 momjian Exp $
*
* NOTES
* The client *requires* a valid server certificate. Since
@@ -867,10 +867,16 @@ init_ssl_system(PGconn *conn)
#ifndef WIN32
static pthread_mutex_t init_mutex = PTHREAD_MUTEX_INITIALIZER;
#else
- static pthread_mutex_t init_mutex;
- static long mutex_initialized = 0L;
- if (!InterlockedExchange(&mutex_initialized, 1L))
- pthread_mutex_init(&init_mutex, NULL);
+ static pthread_mutex_t init_mutex = NULL;
+ static long mutex_initlock = 0;
+
+ if (init_mutex == NULL) {
+ while(InterlockedExchange(&mutex_initlock, 1) == 1)
+ /* loop, another thread own the lock */ ;
+ if (init_mutex == NULL)
+ pthread_mutex_init(&init_mutex, NULL);
+ InterlockedExchange(&mutex_initlock,0);
+ }
#endif
pthread_mutex_lock(&init_mutex);
--
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