px4_autopilot/apps/examples/px4_deamon_app/px4_deamon_app.c

/****************************************************************************
 *
 *   Copyright (C) 2012 PX4 Development Team. All rights reserved.
 *   Author: @author Example User <mail@example.com>
 *
 * 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_deamon_app.c
 * Deamon application example for PX4 autopilot
 */

#include <nuttx/config.h>
#include <unistd.h>
#include <stdio.h>

static bool thread_should_exit = false;		/**< Deamon exit flag */
static bool thread_running = false;		/**< Deamon status flag */
static int deamon_task;				/**< Handle of deamon task / thread */

/**
 * Deamon management function.
 */
__EXPORT int px4_deamon_app_main(int argc, char *argv[]);

/**
 * Mainloop of deamon.
 */
int px4_deamon_thread_main(int argc, char *argv[]);

/**
 * Print the correct usage.
 */
static void usage(const char *reason);

static void
usage(const char *reason)
{
	if (reason)
		fprintf(stderr, "%s\n", reason);
	fprintf(stderr, "usage: deamon {start|stop|status} [-p <additional params>]\n\n");
	exit(1);
}

/**
 * The deamon app only briefly exists to start
 * the background job. The stack size assigned in the
 * Makefile does only apply to this management task.
 * 
 * The actual stack size should be set in the call
 * to task_create().
 */
int px4_deamon_app_main(int argc, char *argv[])
{
	if (argc < 1)
		usage("missing command");

	if (!strcmp(argv[1], "start")) {

		if (thread_running) {
			printf("deamon already running\n");
			/* this is not an error */
			exit(0);
		}

		thread_should_exit = false;
		deamon_task = task_spawn("deamon",
					 SCHED_DEFAULT,
					 SCHED_PRIORITY_DEFAULT,
					 4096,
					 px4_deamon_thread_main,
					 (argv) ? (const char **)&argv[2] : (const char **)NULL);
		exit(0);
	}

	if (!strcmp(argv[1], "stop")) {
		thread_should_exit = true;
		exit(0);
	}

	if (!strcmp(argv[1], "status")) {
		if (thread_running) {
			printf("\tdeamon app is running\n");
		} else {
			printf("\tdeamon app not started\n");
		}
		exit(0);
	}

	usage("unrecognized command");
	exit(1);
}

int px4_deamon_thread_main(int argc, char *argv[]) {

	printf("[deamon] starting\n");

	thread_running = true;

	while (!thread_should_exit) {
		printf("Hello Deamon!\n");
		sleep(10);
	}

	printf("[deamon] exiting.\n");

	thread_running = false;

	return 0;
}