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-rw-r--r--win/tclWinThrd.c83
1 files changed, 81 insertions, 2 deletions
diff --git a/win/tclWinThrd.c b/win/tclWinThrd.c
index 2413a78..2f2825f 100644
--- a/win/tclWinThrd.c
+++ b/win/tclWinThrd.c
@@ -23,6 +23,16 @@ _CRTIMP unsigned int __cdecl _controlfp (unsigned int unNew, unsigned int unMask
#endif
/*
+ * This is the number of milliseconds to wait between internal retries in
+ * the Tcl_MutexLock function. This value must be greater than or equal
+ * to zero and should be a suitable value for the given platform.
+ */
+
+#ifndef TCL_MUTEX_LOCK_SLEEP_TIME
+# define TCL_MUTEX_LOCK_SLEEP_TIME (0)
+#endif
+
+/*
* This is the master lock used to serialize access to other serialization
* data structures.
*/
@@ -56,6 +66,13 @@ static int allocOnce = 0;
#endif /* TCL_THREADS */
/*
+ * The mutexLock serializes Tcl_MutexLock. This is necessary to prevent
+ * races when finalizing a mutex that some other thread may want to lock.
+ */
+
+static CRITICAL_SECTION mutexLock;
+
+/*
* The joinLock serializes Create- and ExitThread. This is necessary to
* prevent a race where a new joinable thread exits before the creating thread
* had the time to create the necessary data structures in the emulation
@@ -368,6 +385,7 @@ TclpInitLock(void)
*/
init = 1;
+ InitializeCriticalSection(&mutexLock);
InitializeCriticalSection(&joinLock);
InitializeCriticalSection(&initLock);
InitializeCriticalSection(&masterLock);
@@ -463,6 +481,52 @@ TclpMasterUnlock(void)
/*
*----------------------------------------------------------------------
*
+ * TclpMutexLock
+ *
+ * This procedure is used to grab a lock that serializes locking
+ * another mutex.
+ *
+ * Results:
+ * None.
+ *
+ * Side effects:
+ * None.
+ *
+ *----------------------------------------------------------------------
+ */
+
+void
+TclpMutexLock(void)
+{
+ EnterCriticalSection(&mutexLock);
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * TclpMutexUnlock
+ *
+ * This procedure is used to release a lock that serializes locking
+ * another mutex.
+ *
+ * Results:
+ * None.
+ *
+ * Side effects:
+ * None.
+ *
+ *----------------------------------------------------------------------
+ */
+
+void
+TclpMutexUnlock(void)
+{
+ LeaveCriticalSection(&mutexLock);
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
* Tcl_GetAllocMutex
*
* This procedure returns a pointer to a statically initialized mutex for
@@ -515,6 +579,7 @@ void
TclFinalizeLock(void)
{
MASTER_LOCK;
+ DeleteCriticalSection(&mutexLock);
DeleteCriticalSection(&joinLock);
/*
@@ -568,6 +633,8 @@ Tcl_MutexLock(
{
CRITICAL_SECTION *csPtr;
+retry:
+
if (*mutexPtr == NULL) {
MASTER_LOCK;
@@ -583,8 +650,20 @@ Tcl_MutexLock(
}
MASTER_UNLOCK;
}
- csPtr = *((CRITICAL_SECTION **)mutexPtr);
- EnterCriticalSection(csPtr);
+ while (1) {
+ TclpMutexLock();
+ csPtr = *((CRITICAL_SECTION **)mutexPtr);
+ if (csPtr == NULL) {
+ TclpMutexUnlock();
+ goto retry;
+ }
+ if (TryEnterCriticalSection(csPtr)) {
+ TclpMutexUnlock();
+ return;
+ }
+ TclpMutexUnlock();
+ Tcl_Sleep(TCL_MUTEX_LOCK_SLEEP_TIME);
+ }
}
/*