- Add libthr but don't hook it up to the regular build yet. This is an

   adaptation of libc_r for the thr system call interface.  This is beta
   quality code.

1 files changed, 257 insertions, 0 deletions

diff --git a/lib/libthr/thread/thr_sem.c b/lib/libthr/thread/thr_sem.c
new file mode 100644
index 0000000..17059e3
--- /dev/null
+++ b/lib/libthr/thread/thr_sem.c
@@ -0,0 +1,257 @@
+/*
+ * 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 <stdlib.h>
+#include <errno.h>
+#include <semaphore.h>
+#include <pthread.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_trywait, sem_trywait);
+__weak_reference(_sem_post, sem_post);
+__weak_reference(_sem_getvalue, sem_getvalue);
+
+
+int
+_sem_init(sem_t *sem, int pshared, unsigned int value)
+{
+	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 (value > SEM_VALUE_MAX) {
+		errno = EINVAL;
+		retval = -1;
+		goto RETURN;
+	}
+
+	*sem = (sem_t)malloc(sizeof(struct sem));
+	if (*sem == NULL) {
+		errno = ENOSPC;
+		retval = -1;
+		goto RETURN;
+	}
+
+	/*
+	 * Initialize the semaphore.
+	 */
+	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;
+}
+
+int
+_sem_destroy(sem_t *sem)
+{
+	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;
+
+	free(*sem);
+
+	retval = 0;
+  RETURN:
+	return retval;
+}
+
+sem_t *
+_sem_open(const char *name, int oflag, ...)
+{
+	errno = ENOSYS;
+	return SEM_FAILED;
+}
+
+int
+_sem_close(sem_t *sem)
+{
+	errno = ENOSYS;
+	return -1;
+}
+
+int
+_sem_unlink(const char *name)
+{
+	errno = ENOSYS;
+	return -1;
+}
+
+int
+_sem_wait(sem_t *sem)
+{
+	int	retval;
+
+	_thread_enter_cancellation_point();
+	
+	_SEM_CHECK_VALIDITY(sem);
+
+	pthread_mutex_lock(&(*sem)->lock);
+
+	while ((*sem)->count == 0) {
+		(*sem)->nwaiters++;
+		pthread_cond_wait(&(*sem)->gtzero, &(*sem)->lock);
+		(*sem)->nwaiters--;
+	}
+	(*sem)->count--;
+
+	pthread_mutex_unlock(&(*sem)->lock);
+
+	retval = 0;
+  RETURN:
+	_thread_leave_cancellation_point();
+	return retval;
+}
+
+int
+_sem_trywait(sem_t *sem)
+{
+	int	retval;
+
+	_SEM_CHECK_VALIDITY(sem);
+
+	pthread_mutex_lock(&(*sem)->lock);
+
+	if ((*sem)->count > 0) {
+		(*sem)->count--;
+		retval = 0;
+	} else {
+		errno = EAGAIN;
+		retval = -1;
+	}
+	
+	pthread_mutex_unlock(&(*sem)->lock);
+
+  RETURN:
+	return retval;
+}
+
+int
+_sem_post(sem_t *sem)
+{
+	pthread_t curthread;
+	int	retval;
+
+	_SEM_CHECK_VALIDITY(sem);
+
+	curthread = _get_curthread();
+	/*
+	 * sem_post() is required to be safe to call from within signal
+	 * handlers.  Thus, we must defer signals.
+	 */
+	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;
+}
+
+int
+_sem_getvalue(sem_t *sem, int *sval)
+{
+	int	retval;
+
+	_SEM_CHECK_VALIDITY(sem);
+
+	pthread_mutex_lock(&(*sem)->lock);
+	*sval = (int)(*sem)->count;
+	pthread_mutex_unlock(&(*sem)->lock);
+
+	retval = 0;
+  RETURN:
+	return retval;
+}