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authorrpj <rpj>1999-08-12 01:32:02 +0000
committerrpj <rpj>1999-08-12 01:32:02 +0000
commit9af51e470791639995bb34bd3198014dc11e2fef (patch)
tree8b06f29abbaf8d1cc027bab0731a9fe79db69413 /condvar.c
parent77d0a6ff70ef2bb480c927e563340fc501ec0930 (diff)
Merged patches to main trunk.
Diffstat (limited to 'condvar.c')
-rw-r--r--condvar.c52
1 files changed, 42 insertions, 10 deletions
diff --git a/condvar.c b/condvar.c
index 580c379..c84a32a 100644
--- a/condvar.c
+++ b/condvar.c
@@ -459,14 +459,21 @@ pthread_cond_destroy (pthread_cond_t * cond)
if (cv != (pthread_cond_t) _PTHREAD_OBJECT_AUTO_INIT)
{
+ if (pthread_mutex_lock(&(cv->waitersLock)) != 0)
+ {
+ return EINVAL;
+ }
+
if (cv->waiters > 0)
{
+ (void) pthread_mutex_unlock(&(cv->waitersLock));
return EBUSY;
}
(void) sem_destroy (&(cv->sema));
- (void) pthread_mutex_destroy (&(cv->waitersLock));
(void) CloseHandle (cv->waitersDone);
+ (void) pthread_mutex_unlock(&(cv->waitersLock));
+ (void) pthread_mutex_destroy (&(cv->waitersLock));
free(cv);
}
@@ -510,10 +517,22 @@ cond_timedwait (pthread_cond_t * cond,
cv = *cond;
/*
- * OK to increment cond->waiters because the caller locked 'mutex'
+ * It's not OK to increment cond->waiters while the caller locked 'mutex',
+ * there may be other threads just waking up (with 'mutex' unlocked)
+ * and cv->... data is not protected.
*/
+ if (pthread_mutex_lock(&(cv->waitersLock)) != 0)
+ {
+ return EINVAL;
+ }
+
cv->waiters++;
+ if (pthread_mutex_unlock(&(cv->waitersLock)) != 0)
+ {
+ return EINVAL;
+ }
+
/*
* We keep the lock held just long enough to increment the count of
* waiters by one (above).
@@ -527,6 +546,7 @@ cond_timedwait (pthread_cond_t * cond,
* Wait to be awakened by
* pthread_cond_signal, or
* pthread_cond_broadcast
+ * timeout
*
* Note:
* _pthread_sem_timedwait is a cancellation point,
@@ -548,10 +568,10 @@ cond_timedwait (pthread_cond_t * cond,
if ((internal_result = pthread_mutex_lock (&(cv->waitersLock))) == 0)
{
/*
- * By making the waiter responsible for decrementing
- * its count we don't have to worry about having an internal
- * mutex.
+ * The waiter is responsible for decrementing
+ * its count, protected by an internal mutex.
*/
+
cv->waiters--;
lastWaiter = cv->wasBroadcast && (cv->waiters == 0);
@@ -559,7 +579,7 @@ cond_timedwait (pthread_cond_t * cond,
internal_result = pthread_mutex_unlock (&(cv->waitersLock));
}
- if (result == 0 && internal_result == 0)
+ if ((result == 0 || result == ETIMEDOUT) && internal_result == 0)
{
if (lastWaiter)
{
@@ -576,7 +596,7 @@ cond_timedwait (pthread_cond_t * cond,
/*
* We must always regain the external mutex, even when
- * errors occur because that's the guarantee that we give
+ * errors occur, because that's the guarantee that we give
* to our callers
*/
(void) pthread_mutex_lock (mutex);
@@ -760,6 +780,7 @@ pthread_cond_signal (pthread_cond_t * cond)
/*
* No-op if the CV is static and hasn't been initialised yet.
+ * Assuming that race conditions are harmless.
*/
if (cv == (pthread_cond_t) _PTHREAD_OBJECT_AUTO_INIT)
{
@@ -768,6 +789,7 @@ pthread_cond_signal (pthread_cond_t * cond)
/*
* If there aren't any waiters, then this is a no-op.
+ * Assuming that race conditions are harmless.
*/
if (cv->waiters > 0)
{
@@ -817,6 +839,7 @@ pthread_cond_broadcast (pthread_cond_t * cond)
*/
{
int result = 0;
+ int wereWaiters = FALSE;
pthread_cond_t cv;
if (cond == NULL || *cond == NULL)
@@ -828,13 +851,20 @@ pthread_cond_broadcast (pthread_cond_t * cond)
/*
* No-op if the CV is static and hasn't been initialised yet.
+ * Assuming that any race condition is harmless.
*/
if (cv == (pthread_cond_t) _PTHREAD_OBJECT_AUTO_INIT)
{
return 0;
}
+ if (pthread_mutex_lock(&(cv->waitersLock)) == EINVAL)
+ {
+ return EINVAL;
+ }
+
cv->wasBroadcast = TRUE;
+ wereWaiters = (cv->waiters > 0);
/*
* Wake up all waiters
@@ -843,14 +873,16 @@ pthread_cond_broadcast (pthread_cond_t * cond)
? 0
: EINVAL);
- if (cv->waiters > 0 && result == 0)
+ (void) pthread_mutex_unlock(&(cv->waitersLock));
+
+ if (wereWaiters && result == 0)
{
/*
* Wait for all the awakened threads to acquire their part of
* the counting semaphore
*/
- if (WaitForSingleObject (cv->waitersDone, INFINITE) ==
- WAIT_OBJECT_0)
+ if (WaitForSingleObject (cv->waitersDone, INFINITE)
+ == WAIT_OBJECT_0)
{
result = 0;
}