1 files changed, 173 insertions, 159 deletions

diff --git a/lib/libthr/thread/thr_sem.c b/lib/libthr/thread/thr_sem.c
index c634034..bd952ef 100644
--- a/lib/libthr/thread/thr_sem.c
+++ b/lib/libthr/thread/thr_sem.c
@@ -1,4 +1,5 @@
 /*
+ * Copyright (C) 2005 David Xu <davidxu@freebsd.org>.
  * Copyright (C) 2000 Jason Evans <jasone@freebsd.org>.
  * All rights reserved.
  * 
@@ -29,227 +30,240 @@
  * $FreeBSD$
  */
 
-#include <stdlib.h>
+#include "namespace.h"
+#include <sys/queue.h>
 #include <errno.h>
-#include <semaphore.h>
+#include <fcntl.h>
 #include <pthread.h>
+#include <semaphore.h>
+#include <stdlib.h>
+#include <time.h>
+#include <_semaphore.h>
+#include "un-namespace.h"
+
 #include "thr_private.h"
 
-#define _SEM_CHECK_VALIDITY(sem)		\
-	if ((*(sem))->magic != SEM_MAGIC) {	\
-		errno = EINVAL;			\
-		retval = -1;			\
-		goto RETURN;			\
-	}
 
 __weak_reference(_sem_init, sem_init);
 __weak_reference(_sem_destroy, sem_destroy);
-__weak_reference(_sem_open, sem_open);
-__weak_reference(_sem_close, sem_close);
-__weak_reference(_sem_unlink, sem_unlink);
-__weak_reference(_sem_wait, sem_wait);
+__weak_reference(_sem_getvalue, sem_getvalue);
 __weak_reference(_sem_trywait, sem_trywait);
+__weak_reference(_sem_wait, sem_wait);
+__weak_reference(_sem_timedwait, sem_timedwait);
 __weak_reference(_sem_post, sem_post);
-__weak_reference(_sem_getvalue, sem_getvalue);
 
 
-int
-_sem_init(sem_t *sem, int pshared, unsigned int value)
+static inline int
+sem_check_validity(sem_t *sem)
 {
-	int	retval;
 
-	/*
-	 * Range check the arguments.
-	 */
-	if (pshared != 0) {
-		/*
-		 * The user wants a semaphore that can be shared among
-		 * processes, which this implementation can't do.  Sounds like a
-		 * permissions problem to me (yeah right).
-		 */
-		errno = EPERM;
-		retval = -1;
-		goto RETURN;
+	if ((sem != NULL) && ((*sem)->magic == SEM_MAGIC))
+		return (0);
+	else {
+		errno = EINVAL;
+		return (-1);
 	}
+}
+
+static sem_t
+sem_alloc(unsigned int value, semid_t semid, int system_sem)
+{
+	sem_t sem;
 
 	if (value > SEM_VALUE_MAX) {
 		errno = EINVAL;
-		retval = -1;
-		goto RETURN;
+		return (NULL);
 	}
 
-	*sem = (sem_t)malloc(sizeof(struct sem));
-	if (*sem == NULL) {
+	sem = (sem_t)malloc(sizeof(struct sem));
+	if (sem == NULL) {
 		errno = ENOSPC;
-		retval = -1;
-		goto RETURN;
+		return (NULL);
 	}
-
+	_thr_umtx_init((umtx_t *)&sem->lock);
 	/*
-	 * Initialize the semaphore.
+	 * Fortunatly count and nwaiters are adjacency, so we can
+	 * use umtx_wait to wait on it, umtx_wait needs an address
+	 * can be accessed as a long interger.
 	 */
-	if (pthread_mutex_init(&(*sem)->lock, NULL) != 0) {
-		free(*sem);
-		errno = ENOSPC;
-		retval = -1;
-		goto RETURN;
-	}
-
-	if (pthread_cond_init(&(*sem)->gtzero, NULL) != 0) {
-		pthread_mutex_destroy(&(*sem)->lock);
-		free(*sem);
-		errno = ENOSPC;
-		retval = -1;
-		goto RETURN;
-	}
-	
-	(*sem)->count = (u_int32_t)value;
-	(*sem)->nwaiters = 0;
-	(*sem)->magic = SEM_MAGIC;
-
-	retval = 0;
-  RETURN:
-	return retval;
+	sem->count = (u_int32_t)value;
+	sem->nwaiters = 0;
+	sem->magic = SEM_MAGIC;
+	sem->semid = semid;
+	sem->syssem = system_sem;
+	return (sem);
 }
 
 int
-_sem_destroy(sem_t *sem)
+_sem_init(sem_t *sem, int pshared, unsigned int value)
 {
-	int	retval;
-	
-	_SEM_CHECK_VALIDITY(sem);
-
-	/* Make sure there are no waiters. */
-	pthread_mutex_lock(&(*sem)->lock);
-	if ((*sem)->nwaiters > 0) {
-		pthread_mutex_unlock(&(*sem)->lock);
-		errno = EBUSY;
-		retval = -1;
-		goto RETURN;
-	}
-	pthread_mutex_unlock(&(*sem)->lock);
-	
-	pthread_mutex_destroy(&(*sem)->lock);
-	pthread_cond_destroy(&(*sem)->gtzero);
-	(*sem)->magic = 0;
+	semid_t semid;
 
-	free(*sem);
+	semid = (semid_t)SEM_USER;
+	if ((pshared != 0) && (ksem_init(&semid, value) != 0))
+		return (-1);
 
-	retval = 0;
-  RETURN:
-	return retval;
-}
-
-sem_t *
-_sem_open(const char *name, int oflag, ...)
-{
-	errno = ENOSYS;
-	return SEM_FAILED;
+	(*sem) = sem_alloc(value, semid, pshared);
+	if ((*sem) == NULL) {
+		if (pshared != 0)
+			ksem_destroy(semid);
+		return (-1);
+	}
+	return (0);
 }
 
 int
-_sem_close(sem_t *sem)
+_sem_destroy(sem_t *sem)
 {
-	errno = ENOSYS;
-	return -1;
-}
+	int retval;
 
-int
-_sem_unlink(const char *name)
-{
-	errno = ENOSYS;
-	return -1;
+	if (sem_check_validity(sem) != 0)
+		return (-1);
+
+	/*
+	 * If this is a system semaphore let the kernel track it otherwise
+	 * make sure there are no waiters.
+	 */
+	if ((*sem)->syssem != 0)
+		retval = ksem_destroy((*sem)->semid);
+	else {
+		retval = 0;
+		(*sem)->magic = 0;
+	}
+	if (retval == 0)
+		free(*sem);
+	return (retval);
 }
 
 int
-_sem_wait(sem_t *sem)
+_sem_getvalue(sem_t * __restrict sem, int * __restrict sval)
 {
-	int	retval;
+	int retval;
 
-	_thread_enter_cancellation_point();
-	
-	_SEM_CHECK_VALIDITY(sem);
-
-	pthread_mutex_lock(&(*sem)->lock);
+	if (sem_check_validity(sem) != 0)
+		return (-1);
 
-	while ((*sem)->count == 0) {
-		(*sem)->nwaiters++;
-		pthread_cond_wait(&(*sem)->gtzero, &(*sem)->lock);
-		(*sem)->nwaiters--;
+	if ((*sem)->syssem != 0)
+		retval = ksem_getvalue((*sem)->semid, sval);
+        else {
+		*sval = (int)(*sem)->count;
+		retval = 0;
 	}
-	(*sem)->count--;
-
-	pthread_mutex_unlock(&(*sem)->lock);
-
-	retval = 0;
-  RETURN:
-	_thread_leave_cancellation_point();
-	return retval;
+	return (retval);
 }
 
 int
 _sem_trywait(sem_t *sem)
 {
-	int	retval;
+	int val;
 
-	_SEM_CHECK_VALIDITY(sem);
+	if (sem_check_validity(sem) != 0)
+		return (-1);
 
-	pthread_mutex_lock(&(*sem)->lock);
+	if ((*sem)->syssem != 0)
+ 		return (ksem_trywait((*sem)->semid));
 
-	if ((*sem)->count > 0) {
-		(*sem)->count--;
-		retval = 0;
-	} else {
-		errno = EAGAIN;
-		retval = -1;
+	while ((val = (*sem)->count) > 0) {
+		if (atomic_cmpset_acq_int(&(*sem)->count, val, val - 1))
+			return (0);
 	}
-	
-	pthread_mutex_unlock(&(*sem)->lock);
-
-  RETURN:
-	return retval;
+	errno = EAGAIN;
+	return (-1);
 }
 
 int
-_sem_post(sem_t *sem)
+_sem_wait(sem_t *sem)
 {
-	int	retval;
+	struct pthread *curthread;
+	int val, oldcancel, retval;
+
+	if (sem_check_validity(sem) != 0)
+		return (-1);
+
+	curthread = _get_curthread();
+	if ((*sem)->syssem != 0) {
+		oldcancel = _thr_cancel_enter(curthread);
+		retval = ksem_wait((*sem)->semid);
+		_thr_cancel_leave(curthread, oldcancel);
+		return (retval);
+	}
 
-	_SEM_CHECK_VALIDITY(sem);
+	_pthread_testcancel();
+	do {
+		while ((val = (*sem)->count) > 0) {
+			if (atomic_cmpset_acq_int(&(*sem)->count, val, val - 1))
+				return (0);
+		}
+		oldcancel = _thr_cancel_enter(curthread);
+		retval = _thr_umtx_wait((umtx_t *)&(*sem)->count, 0, NULL);
+		_thr_cancel_leave(curthread, oldcancel);
+	} while (retval == 0);
+	errno = retval;
+	return (-1);
+}
+
+int
+_sem_timedwait(sem_t * __restrict sem, struct timespec * __restrict abstime)
+{
+	struct timespec ts, ts2;
+	struct pthread *curthread;
+	int val, oldcancel, retval;
+
+	if (sem_check_validity(sem) != 0)
+		return (-1);
+
+	curthread = _get_curthread();
+	if ((*sem)->syssem != 0) {
+		oldcancel = _thr_cancel_enter(curthread);
+		retval = ksem_timedwait((*sem)->semid, abstime);
+		_thr_cancel_leave(curthread, oldcancel);
+		return (retval);
+	}
 
 	/*
-	 * sem_post() is required to be safe to call from within signal
-	 * handlers.  Thus, we must defer signals.
+	 * The timeout argument is only supposed to
+	 * be checked if the thread would have blocked.
 	 */
-	pthread_mutex_lock(&(*sem)->lock);
-
-	/* GIANT_LOCK(curthread); */
-
-	(*sem)->count++;
-	if ((*sem)->nwaiters > 0)
-		pthread_cond_signal(&(*sem)->gtzero);
-
-	/* GIANT_UNLOCK(curthread); */
-
-	pthread_mutex_unlock(&(*sem)->lock);
-
-	retval = 0;
-  RETURN:
-	return retval;
+	_pthread_testcancel();
+	do {
+		while ((val = (*sem)->count) > 0) {
+			if (atomic_cmpset_acq_int(&(*sem)->count, val, val - 1))
+				return (0);
+		}
+		if (abstime == NULL) {
+			errno = EINVAL;
+			return (-1);
+		}
+		clock_gettime(CLOCK_REALTIME, &ts);
+		TIMESPEC_SUB(&ts2, abstime, &ts);
+		oldcancel = _thr_cancel_enter(curthread);
+		retval = _thr_umtx_wait((umtx_t *)&(*sem)->count, 0, &ts2);
+		_thr_cancel_leave(curthread, oldcancel);
+	} while (retval == 0);
+	errno = retval;
+	return (-1);
 }
 
 int
-_sem_getvalue(sem_t *sem, int *sval)
+_sem_post(sem_t *sem)
 {
-	int	retval;
-
-	_SEM_CHECK_VALIDITY(sem);
+	int val, retval;
+	
+	if (sem_check_validity(sem) != 0)
+		return (-1);
 
-	pthread_mutex_lock(&(*sem)->lock);
-	*sval = (int)(*sem)->count;
-	pthread_mutex_unlock(&(*sem)->lock);
+	if ((*sem)->syssem != 0)
+		return (ksem_post((*sem)->semid));
 
-	retval = 0;
-  RETURN:
-	return retval;
+	/*
+	 * sem_post() is required to be safe to call from within
+	 * signal handlers, these code should work as that.
+	 */
+	do {
+		val = (*sem)->count;
+	} while (!atomic_cmpset_acq_int(&(*sem)->count, val, val + 1));
+	retval = _thr_umtx_wake((umtx_t *)&(*sem)->count, val + 1);
+	if (retval > 0)
+		retval = 0;
+	return (retval);
 }