1 files changed, 262 insertions, 0 deletions
diff --git a/lib/libpthread/thread/thr_sem.c b/lib/libpthread/thread/thr_sem.c
new file mode 100644
index 0000000..b347a12
--- /dev/null
+++ b/lib/libpthread/thread/thr_sem.c
@@ -0,0 +1,262 @@
+/*
+ * Copyright (C) 2000 Jason Evans <jasone@freebsd.org>.
+ * All rights reserved.
+ * 
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice(s), this list of conditions and the following disclaimer as
+ *    the first lines of this file unmodified other than the possible
+ *    addition of one or more copyright notices.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice(s), this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) ``AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
+ * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
+ * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
+ * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * $FreeBSD$
+ */
+
+#include "namespace.h"
+#include <sys/queue.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <pthread.h>
+#include <semaphore.h>
+#include <stdlib.h>
+#include <time.h>
+#include <_semaphore.h>
+#include "un-namespace.h"
+#include "libc_private.h"
+#include "thr_private.h"
+
+
+extern int pthread_cond_wait(pthread_cond_t *, pthread_mutex_t *);
+extern int pthread_cond_timedwait(pthread_cond_t *, pthread_mutex_t *,
+		struct timespec *);
+
+__weak_reference(_sem_init, sem_init);
+__weak_reference(_sem_wait, sem_wait);
+__weak_reference(_sem_timedwait, sem_timedwait);
+__weak_reference(_sem_post, sem_post);
+
+
+static inline int
+sem_check_validity(sem_t *sem)
+{
+
+	if ((sem != NULL) && ((*sem)->magic == SEM_MAGIC))
+		return (0);
+	else {
+		errno = EINVAL;
+		return (-1);
+	}
+}
+
+static void
+decrease_nwaiters(void *arg)
+{
+	sem_t *sem = (sem_t *)arg;
+
+	(*sem)->nwaiters--;
+	/*
+	 * this function is called from cancellation point,
+	 * the mutex should already be hold.
+	 */
+	_pthread_mutex_unlock(&(*sem)->lock);
+}
+
+static sem_t
+sem_alloc(unsigned int value, semid_t semid, int system_sem)
+{
+	sem_t sem;
+
+	if (value > SEM_VALUE_MAX) {
+		errno = EINVAL;
+		return (NULL);
+	}
+
+	sem = (sem_t)malloc(sizeof(struct sem));
+	if (sem == NULL) {
+		errno = ENOSPC;
+		return (NULL);
+	}
+
+	/*
+	 * Initialize the semaphore.
+	 */
+	if (_pthread_mutex_init(&sem->lock, NULL) != 0) {
+		free(sem);
+		errno = ENOSPC;
+		return (NULL);
+	}
+
+	if (_pthread_cond_init(&sem->gtzero, NULL) != 0) {
+		_pthread_mutex_destroy(&sem->lock);
+		free(sem);
+		errno = ENOSPC;
+		return (NULL);
+	}
+
+	sem->count = (u_int32_t)value;
+	sem->nwaiters = 0;
+	sem->magic = SEM_MAGIC;
+	sem->semid = semid;
+	sem->syssem = system_sem;
+	return (sem);
+}
+
+int
+_sem_init(sem_t *sem, int pshared, unsigned int value)
+{
+	semid_t semid;
+
+	semid = SEM_USER;
+	if ((pshared != 0) && (ksem_init(&semid, value) != 0))
+		return (-1);
+
+	(*sem) = sem_alloc(value, semid, pshared);
+	if ((*sem) == NULL) {
+		if (pshared != 0)
+			ksem_destroy(semid);
+		return (-1);
+	}
+	return (0);
+}
+
+int
+_sem_wait(sem_t *sem)
+{
+	struct pthread *curthread;
+	int retval;
+
+	if (sem_check_validity(sem) != 0)
+		return (-1);
+
+	if ((*sem)->syssem != 0) {
+		curthread = _get_curthread();
+		_thr_cancel_enter(curthread);
+		retval = ksem_wait((*sem)->semid);
+		_thr_cancel_leave(curthread, retval != 0);
+	}
+	else {
+		pthread_testcancel();
+		_pthread_mutex_lock(&(*sem)->lock);
+
+		while ((*sem)->count <= 0) {
+			(*sem)->nwaiters++;
+			pthread_cleanup_push(decrease_nwaiters, sem);
+			pthread_cond_wait(&(*sem)->gtzero, &(*sem)->lock);
+			pthread_cleanup_pop(0);
+			(*sem)->nwaiters--;
+		}
+		(*sem)->count--;
+
+		_pthread_mutex_unlock(&(*sem)->lock);
+
+		retval = 0;
+	}
+	return (retval);
+}
+
+int
+_sem_timedwait(sem_t * __restrict sem,
+    struct timespec * __restrict abs_timeout)
+{
+	struct pthread *curthread;
+	int retval;
+	int timeout_invalid;
+
+	if (sem_check_validity(sem) != 0)
+		return (-1);
+
+	if ((*sem)->syssem != 0) {
+		curthread = _get_curthread();
+		_thr_cancel_enter(curthread);
+		retval = ksem_timedwait((*sem)->semid, abs_timeout);
+		_thr_cancel_leave(curthread, retval != 0);
+	}
+	else {
+		/*
+		 * The timeout argument is only supposed to
+		 * be checked if the thread would have blocked.
+		 * This is checked outside of the lock so a
+		 * segfault on an invalid address doesn't end
+		 * up leaving the mutex locked.
+		 */
+		pthread_testcancel();
+		timeout_invalid = (abs_timeout->tv_nsec >= 1000000000) ||
+		    (abs_timeout->tv_nsec < 0);
+		_pthread_mutex_lock(&(*sem)->lock);
+
+		if ((*sem)->count <= 0) {
+			if (timeout_invalid) {
+				_pthread_mutex_unlock(&(*sem)->lock);
+				errno = EINVAL;
+				return (-1);
+			}
+			(*sem)->nwaiters++;
+			pthread_cleanup_push(decrease_nwaiters, sem);
+			pthread_cond_timedwait(&(*sem)->gtzero,
+			    &(*sem)->lock, abs_timeout);
+			pthread_cleanup_pop(0);
+			(*sem)->nwaiters--;
+		}
+		if ((*sem)->count == 0) {
+			errno = ETIMEDOUT;
+			retval = -1;
+		}
+		else {
+			(*sem)->count--;
+			retval = 0;
+		}	
+
+		_pthread_mutex_unlock(&(*sem)->lock);
+	}
+
+	return (retval);
+}
+
+int
+_sem_post(sem_t *sem)
+{
+	struct pthread *curthread;
+	int retval;
+	
+	if (sem_check_validity(sem) != 0)
+		return (-1);
+
+	if ((*sem)->syssem != 0)
+		retval = ksem_post((*sem)->semid);
+	else {
+		/*
+		 * sem_post() is required to be safe to call from within
+		 * signal handlers.  Thus, we must enter a critical region.
+		 */
+		curthread = _get_curthread();
+		_thr_critical_enter(curthread);
+		_pthread_mutex_lock(&(*sem)->lock);
+
+		(*sem)->count++;
+		if ((*sem)->nwaiters > 0)
+			_pthread_cond_signal(&(*sem)->gtzero);
+
+		_pthread_mutex_unlock(&(*sem)->lock);
+		_thr_critical_leave(curthread);
+		retval = 0;
+	}
+
+	return (retval);
+}