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* Copyright (c) 2013-2015 PX4 Development Team. All rights reserved.
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/**
* @file land_detector_main.cpp
* Land detection algorithm
*
* @author Johan Jansen <jnsn.johan@gmail.com>
*/
#include <unistd.h> //usleep
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <errno.h>
#include <drivers/drv_hrt.h>
#include <systemlib/systemlib.h> //Scheduler
#include <systemlib/err.h> //print to console
#include "FixedwingLandDetector.h"
#include "MulticopterLandDetector.h"
//Function prototypes
static int land_detector_start(const char *mode);
static void land_detector_stop();
/**
* land detector app start / stop handling function
* This makes the land detector module accessible from the nuttx shell
* @ingroup apps
*/
extern "C" __EXPORT int land_detector_main(int argc, char *argv[]);
//Private variables
static LandDetector *land_detector_task = nullptr;
static int _landDetectorTaskID = -1;
static char _currentMode[12];
/**
* Deamon thread function
**/
static void land_detector_deamon_thread(int argc, char *argv[])
{
land_detector_task->start();
}
/**
* Stop the task, force killing it if it doesn't stop by itself
**/
static void land_detector_stop()
{
if (land_detector_task == nullptr || _landDetectorTaskID == -1) {
errx(1, "not running");
return;
}
land_detector_task->shutdown();
//Wait for task to die
int i = 0;
do {
/* wait 20ms */
usleep(20000);
/* if we have given up, kill it */
if (++i > 50) {
task_delete(_landDetectorTaskID);
break;
}
} while (land_detector_task->isRunning());
delete land_detector_task;
land_detector_task = nullptr;
_landDetectorTaskID = -1;
errx(0, "land_detector has been stopped");
}
/**
* Start new task, fails if it is already running. Returns OK if successful
**/
static int land_detector_start(const char *mode)
{
if (land_detector_task != nullptr || _landDetectorTaskID != -1) {
errx(1, "already running");
return -1;
}
//Allocate memory
if (!strcmp(mode, "fixedwing")) {
land_detector_task = new FixedwingLandDetector();
} else if (!strcmp(mode, "multicopter")) {
land_detector_task = new MulticopterLandDetector();
} else {
errx(1, "[mode] must be either 'fixedwing' or 'multicopter'");
return -1;
}
//Check if alloc worked
if (land_detector_task == nullptr) {
errx(1, "alloc failed");
return -1;
}
//Start new thread task
_landDetectorTaskID = task_spawn_cmd("land_detector",
SCHED_DEFAULT,
SCHED_PRIORITY_DEFAULT,
1000,
(main_t)&land_detector_deamon_thread,
nullptr);
if (_landDetectorTaskID < 0) {
errx(1, "task start failed: %d", -errno);
return -1;
}
/* avoid memory fragmentation by not exiting start handler until the task has fully started */
const uint32_t timeout = hrt_absolute_time() + 5000000; //5 second timeout
while (!land_detector_task->isRunning()) {
usleep(50000);
printf(".");
fflush(stdout);
if (hrt_absolute_time() > timeout) {
err(1, "start failed - timeout");
land_detector_stop();
exit(1);
}
}
printf("\n");
//Remember current active mode
strncpy(_currentMode, mode, 12);
exit(0);
return 0;
}
/**
* Main entry point for this module
**/
int land_detector_main(int argc, char *argv[])
{
if (argc < 2) {
goto exiterr;
}
if (argc >= 2 && !strcmp(argv[1], "start")) {
land_detector_start(argv[2]);
}
if (!strcmp(argv[1], "stop")) {
land_detector_stop();
exit(0);
}
if (!strcmp(argv[1], "status")) {
if (land_detector_task) {
if (land_detector_task->isRunning()) {
warnx("running (%s)", _currentMode);
} else {
errx(1, "exists, but not running (%s)", _currentMode);
}
exit(0);
} else {
errx(1, "not running");
}
}
exiterr:
warnx("usage: land_detector {start|stop|status} [mode]");
warnx("mode can either be 'fixedwing' or 'multicopter'");
return 1;
}