patch from Gary Pennington fixing a possible problem at initialization
* threads.c: patch from Gary Pennington fixing a possible
problem at initialization time.
Daniel
diff --git a/threads.c b/threads.c
index cde26f4..6b32207 100644
--- a/threads.c
+++ b/threads.c
@@ -68,22 +68,15 @@
* This module still has some internal static data.
* - xmlLibraryLock a global lock
* - globalkey used for per-thread data
- * - keylock protecting globalkey
- * - keyonce to mark initialization of globalkey
*/
-static int initialized = 0;
#ifdef HAVE_PTHREAD_H
-static pthread_mutex_t keylock = PTHREAD_MUTEX_INITIALIZER;
static pthread_key_t globalkey;
-static int keyonce = 0;
static pthread_t mainthread;
+static pthread_once_t once_control = PTHREAD_ONCE_INIT;
#endif
static xmlRMutexPtr xmlLibraryLock = NULL;
-
-#if defined(SOLARIS)
-NOTE(DATA_READABLE_WITHOUT_LOCK(keyonce))
-#endif
+static void xmlOnceInit(void);
/**
* xmlMutexPtr:
@@ -291,11 +284,6 @@
* xmlGetGlobalState:
*
* xmlGetGlobalState() is called to retrieve the global state for a thread.
- * keyonce will only be set once during a library invocation and is used
- * to create globalkey, the key used to store each thread's TSD.
- *
- * Note: it should not be called for the "main" thread as this thread uses
- * the existing global variables defined in the library.
*
* Returns the thread global state or NULL in case of error
*/
@@ -305,14 +293,8 @@
#ifdef HAVE_PTHREAD_H
xmlGlobalState *globalval;
- if (keyonce == 0) {
- (void) pthread_mutex_lock(&keylock);
- if (keyonce == 0) {
- keyonce++;
- (void) pthread_key_create(&globalkey, xmlFreeGlobalState);
- }
- (void) pthread_mutex_unlock(&keylock);
- }
+ pthread_once(&once_control, xmlOnceInit);
+
if ((globalval = (xmlGlobalState *)
pthread_getspecific(globalkey)) == NULL) {
xmlGlobalState *tsd = xmlNewGlobalState();
@@ -360,8 +342,9 @@
int
xmlIsMainThread(void)
{
- if (!initialized)
- xmlInitThreads();
+#ifdef HAVE_PTHREAD_H
+ pthread_once(&once_control, xmlOnceInit);
+#endif
#ifdef DEBUG_THREADS
xmlGenericError(xmlGenericErrorContext, "xmlIsMainThread()\n");
@@ -412,18 +395,9 @@
void
xmlInitThreads(void)
{
- if (initialized != 0)
- return;
-
#ifdef DEBUG_THREADS
xmlGenericError(xmlGenericErrorContext, "xmlInitThreads()\n");
#endif
-
-#ifdef HAVE_PTHREAD_H
- mainthread = pthread_self();
-#endif
-
- initialized = 1;
}
/**
@@ -435,12 +409,24 @@
void
xmlCleanupThreads(void)
{
- if (initialized == 0)
- return;
-
#ifdef DEBUG_THREADS
xmlGenericError(xmlGenericErrorContext, "xmlCleanupThreads()\n");
#endif
+}
- initialized = 0;
+/**
+ * xmlOnceInit
+ *
+ * xmlOnceInit() is used to initialize the value of mainthread for use
+ * in other routines. This function should only be called using
+ * pthread_once() in association with the once_control variable to ensure
+ * that the function is only called once. See man pthread_once for more
+ * details.
+ */
+static void
+xmlOnceInit(void) {
+#ifdef HAVE_PTHREAD_H
+ (void) pthread_key_create(&globalkey, xmlFreeGlobalState);
+ mainthread = pthread_self();
+#endif
}