int
pthread_rwlock_rdlock (pthread_rwlock_t * rwlock)
{
int result;
pthread_rwlock_t rwl;
if (rwlock == NULL || *rwlock == NULL)
{
return EINVAL;
}
if (*rwlock == PTHREAD_RWLOCK_INITIALIZER)
{
result = ptw32_rwlock_check_need_init (rwlock);
if (result != 0 && result != EBUSY)
{
return result;
}
}
rwl = *rwlock;
if (rwl->nMagic != PTW32_RWLOCK_MAGIC)
{
return EINVAL;
}
if ((result = pthread_mutex_lock (&(rwl->mtxExclusiveAccess))) != 0)
{
return result;
}
if (++rwl->nSharedAccessCount == INT_MAX)
{
if ((result =
pthread_mutex_lock (&(rwl->mtxSharedAccessCompleted))) != 0)
{
(void) pthread_mutex_unlock (&(rwl->mtxExclusiveAccess));
return result;
}
rwl->nSharedAccessCount -= rwl->nCompletedSharedAccessCount;
rwl->nCompletedSharedAccessCount = 0;
if ((result =
pthread_mutex_unlock (&(rwl->mtxSharedAccessCompleted))) != 0)
{
(void) pthread_mutex_unlock (&(rwl->mtxExclusiveAccess));
return result;
}
}
return (pthread_mutex_unlock (&(rwl->mtxExclusiveAccess)));
}
int
pthread_rwlock_tryrdlock(pthread_rwlock_t * rwlock)
{
int result;
pthread_rwlock_t rwl;
if (rwlock == NULL || *rwlock == NULL)
return EINVAL;
/*
* We do a quick check to see if we need to do more work
* to initialise a static rwlock. We check
* again inside the guarded section of ptw32_rwlock_check_need_init()
* to avoid race conditions.
*/
if (*rwlock == PTHREAD_RWLOCK_INITIALIZER) {
result = ptw32_rwlock_check_need_init(rwlock);
if (result != 0 && result != EBUSY)
return result;
}
rwl = *rwlock;
if (rwl->nMagic != PTW32_RWLOCK_MAGIC)
return EINVAL;
if ((result = pthread_mutex_trylock(&(rwl->mtxExclusiveAccess))) != 0)
return result;
if (++rwl->nSharedAccessCount == INT_MAX) {
if ((result =
pthread_mutex_lock(&(rwl->mtxSharedAccessCompleted))) != 0) {
(void) pthread_mutex_unlock(&(rwl->mtxExclusiveAccess));
return result;
}
rwl->nSharedAccessCount -= rwl->nCompletedSharedAccessCount;
rwl->nCompletedSharedAccessCount = 0;
if ((result =
pthread_mutex_unlock(&(rwl->mtxSharedAccessCompleted))) != 0) {
(void) pthread_mutex_unlock(&(rwl->mtxExclusiveAccess));
return result;
}
}
return (pthread_mutex_unlock(&rwl->mtxExclusiveAccess));
}
int
pthread_rwlock_timedwrlock(pthread_rwlock_t * rwlock,
const struct timespec *abstime)
{
int result;
pthread_rwlock_t rwl;
if (rwlock == NULL || *rwlock == NULL)
return EINVAL;
/*
* We do a quick check to see if we need to do more work
* to initialise a static rwlock. We check
* again inside the guarded section of ptw32_rwlock_check_need_init()
* to avoid race conditions.
*/
if (*rwlock == PTHREAD_RWLOCK_INITIALIZER) {
result = ptw32_rwlock_check_need_init(rwlock);
if (result != 0 && result != EBUSY)
return result;
}
rwl = *rwlock;
if (rwl->nMagic != PTW32_RWLOCK_MAGIC)
return EINVAL;
if ((result =
pthread_mutex_timedlock(&(rwl->mtxExclusiveAccess), abstime)) != 0)
return result;
if ((result =
pthread_mutex_timedlock(&(rwl->mtxSharedAccessCompleted),
abstime)) != 0) {
(void) pthread_mutex_unlock(&(rwl->mtxExclusiveAccess));
return result;
}
if (rwl->nExclusiveAccessCount == 0) {
if (rwl->nCompletedSharedAccessCount > 0) {
rwl->nSharedAccessCount -= rwl->nCompletedSharedAccessCount;
rwl->nCompletedSharedAccessCount = 0;
}
if (rwl->nSharedAccessCount > 0) {
rwl->nCompletedSharedAccessCount = -rwl->nSharedAccessCount;
/*
* This routine may be a cancelation point
* according to POSIX 1003.1j section 18.1.2.
*/
#ifdef _MSC_VER
#pragma inline_depth(0)
#endif
pthread_cleanup_push(ptw32_rwlock_cancelwrwait, (void *) rwl);
do {
result =
pthread_cond_timedwait(&(rwl->cndSharedAccessCompleted),
&(rwl->mtxSharedAccessCompleted),
abstime);
} while (result == 0 && rwl->nCompletedSharedAccessCount < 0);
pthread_cleanup_pop((result != 0) ? 1 : 0);
#ifdef _MSC_VER
#pragma inline_depth()
#endif
if (result == 0)
rwl->nSharedAccessCount = 0;
}
}
if (result == 0)
rwl->nExclusiveAccessCount++;
return result;
}
