POSIX: Add pthread mutex based semaphores

src/platforms/posix/px4_layer/CMakeLists.txt

@@ -37,6 +37,7 @@ px4_add_module(
 	SRCS
 		px4_posix_impl.cpp
 		px4_posix_tasks.cpp
+		px4_sem.cpp
 		lib_crc32.c
 		drv_hrt.c
 		px4_log.c

src/platforms/posix/px4_layer/px4_sem.cpp

@@ -0,0 +1,98 @@
+/****************************************************************************
+ *
+ *   Copyright (c) 2015 PX4 Development Team. 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, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name PX4 nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "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 OWNER OR CONTRIBUTORS 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.
+ *
+ ****************************************************************************/
+
+/**
+ * @file px4_sem.cpp
+ *
+ * PX4 Middleware Wrapper Linux Implementation
+ */
+
+#include <px4_defines.h>
+#include <px4_middleware.h>
+#include <px4_workqueue.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <pthread.h>
+
+#ifdef __PX4_DARWIN
+
+#include <px4_posix.h>
+
+#include <list>
+
+int px4_sem_init(px4_sem_t *s, int pshared, unsigned value)
+{
+	// We do not used the process shared arg
+	(void)pshared;
+	s->value = value;
+	pthread_cond_init(&(s->wait), NULL);
+	pthread_mutex_init(&(s->lock), NULL);
+
+	return 0;
+}
+
+int px4_sem_wait(px4_sem_t *s)
+{
+	pthread_mutex_lock(&(s->lock));
+	s->value--;
+	if(s->value < 0) {
+	        pthread_cond_wait(&(s->wait), &(s->lock));
+	}
+	pthread_mutex_unlock(&(s->lock));
+
+	return 0;
+}
+
+int px4_sem_post(px4_sem_t *s)
+{
+	pthread_mutex_lock(&(s->lock));
+	s->value++;
+	if(s->value <= 0) {
+		pthread_cond_signal(&(s->wait));
+	}
+	pthread_mutex_unlock(&(s->lock));
+
+	return 0;
+}
+
+int px4_sem_destroy(px4_sem_t *s)
+{
+	pthread_mutex_lock(&(s->lock));
+	pthread_cond_destroy(&(s->wait));
+	pthread_mutex_unlock(&(s->lock));
+	pthread_mutex_destroy(&(s->lock));
+
+	return 0;
+}
+
+#endif

src/platforms/px4_posix.h

@@ -48,6 +48,41 @@
 #include <semaphore.h>
 
 
+/* Semaphore handling */
+
+#ifdef __PX4_DARWIN
+
+__BEGIN_DECLS
+
+typedef struct
+{
+	pthread_mutex_t lock;
+	pthread_cond_t wait;
+	int value;
+} px4_sem_t;
+
+__EXPORT int		px4_sem_init(px4_sem_t *s, int pshared, unsigned value);
+__EXPORT int		px4_sem_wait(px4_sem_t *s);
+__EXPORT int		px4_sem_post(px4_sem_t *s);
+__EXPORT int		px4_sem_destroy(px4_sem_t *s);
+
+__END_DECLS
+
+#else
+
+typedef px4_sem_t		sem_t
+
+#define px4_sem_init		_GLOBAL sem_init
+#define px4_sem_wait		_GLOBAL sem_wait
+#define px4_sem_post		_GLOBAL px4_sem_post
+#define px4_sem_destroy		_GLOBAL sem_destroy
+
+
+
+#endif
+
+//###################################
+
 #ifdef __PX4_NUTTX
 
 #define  PX4_F_RDONLY 1