X-Git-Url: https://git.ucc.asn.au/?a=blobdiff_plain;ds=sidebyside;f=server%2Fsensor.c;h=f58daa59140beb9b02e0b51a0e0868b7e721820e;hb=8aa358c02e86aee0486c1951ee3c5634cb7586a1;hp=e69de29bb2d1d6434b8b29ae775ad8c2e48c5391;hpb=b1a8334f97f84e10ee9cef96377bbdcfbf5f945c;p=matches%2FMCTX3420.git

diff --git a/server/sensor.c b/server/sensor.c
index e69de29..f58daa5 100644
--- a/server/sensor.c
+++ b/server/sensor.c
@@ -0,0 +1,353 @@
+/**
+ * @file sensor.c
+ * @brief Implementation of sensor thread
+ * TODO: Finalise implementation
+ */
+
+#include "common.h"
+#include "sensor.h"
+#include "options.h"
+#include <math.h>
+
+/** Array of sensors, initialised by Sensor_Init **/
+static Sensor g_sensors[NUMSENSORS]; //global to this file
+static const char * g_sensor_names[] = {"analog_test0", "analog_test1", "digital_test0", "digital_test1"};
+/**
+ * Read a data value from a sensor; block until value is read
+ * @param sensor_id - The ID of the sensor
+ * @param d - DataPoint to set
+ * @returns NULL for digital sensors when data is unchanged, otherwise d
+ */
+DataPoint * GetData(int sensor_id, DataPoint * d)
+{
+	// switch based on the sensor_id at the moment for testing;
+	// might be able to just directly access ADC from sensor_id?
+	//TODO: Implement for real sensors
+
+	
+	//TODO: We should ensure the time is *never* allowed to change on the server if we use gettimeofday
+	//		Another way people might think of getting the time is to count CPU cycles with clock()
+	//		But this will not work because a) CPU clock speed may change on some devices (RPi?) and b) It counts cycles used by all threads
+	
+	struct timeval t;
+	gettimeofday(&t, NULL);
+	d->time_stamp = (t.tv_sec - g_options.start_time.tv_sec) + 1e-6*(t.tv_usec - g_options.start_time.tv_usec);
+
+	// Make time relative
+	//d->time_stamp.tv_sec -= g_options.start_time.tv_sec;
+	//d->time_stamp.tv_usec -= g_options.start_time.tv_usec;
+	
+	switch (sensor_id)
+	{
+		case ANALOG_TEST0:
+		{
+			static int count = 0;
+			d->value = count++;
+			break;
+		}
+		case ANALOG_TEST1:
+			d->value = (double)(rand() % 100) / 100;
+			break;
+	
+		//TODO: For digital sensors, consider only updating when sensor is actually changed
+		case DIGITAL_TEST0:
+			d->value = t.tv_sec % 2;
+			break;
+		case DIGITAL_TEST1:
+			d->value = (t.tv_sec+1)%2;
+			break;
+		default:
+			Fatal("Unknown sensor id: %d", sensor_id);
+			break;
+	}	
+	usleep(100000); // simulate delay in sensor polling
+
+	return d;
+}
+
+
+/**
+ * Destroy a sensor
+ * @param s - Sensor to destroy
+ */
+void Destroy(Sensor * s)
+{
+	// Maybe move the binary file into long term file storage?
+	fclose(s->file);
+}
+
+
+
+/**
+ * Initialise a sensor
+ * @param s - Sensor to initialise
+ */
+void Init(Sensor * s, int id)
+{
+	s->write_index = 0;
+	s->id = id;
+
+	#define FILENAMESIZE 3
+	char filename[FILENAMESIZE];
+	if (s->id >= pow(10, FILENAMESIZE))
+	{
+		Fatal("Too many sensors! FILENAMESIZE is %d; increase it and recompile.", FILENAMESIZE);
+	}
+
+	pthread_mutex_init(&(s->mutex), NULL);
+		
+	sprintf(filename, "%d", s->id);
+	unlink(filename); //TODO: Move old files somewhere
+
+	s->file = fopen(filename, "a+b"); // open binary file
+	Log(LOGDEBUG, "Initialised sensor %d; binary file is \"%s\"", id, filename);
+}
+
+
+
+
+
+/**
+ * Run the main sensor polling loop
+ * @param arg - Cast to Sensor* - Sensor that the thread will handle
+ * @returns NULL (void* required to use the function with pthreads)
+ */
+void * Sensor_Main(void * arg)
+{
+	Sensor * s = (Sensor*)(arg);
+
+	while (Thread_Runstate() == RUNNING) //TODO: Exit condition
+	{
+		// The sensor will write data to a buffer until it is full
+		// Then it will open a file and dump the buffer to the end of it.
+		// Rinse and repeat
+
+		// The reason I've added the buffer is because locks are expensive
+		// But maybe it's better to just write data straight to the file
+		// I'd like to do some tests by changing SENSOR_DATABUFSIZ
+
+		while (s->write_index < SENSOR_DATABUFSIZ)
+		{
+			DataPoint * d = &(s->buffer[s->write_index]);
+			if (GetData(s->id, d) == NULL)
+			{
+				Fatal("Error collecting data");
+			}
+			s->write_index += 1;
+		}
+
+		//Log(LOGDEBUG, "Filled buffer");
+
+		// CRITICAL SECTION (no threads should be able to read/write the file at the same time)
+		pthread_mutex_lock(&(s->mutex));
+			//TODO: Valgrind complains about this fseek: "Syscall param write(buf) points to uninitialised byte(s)"
+			//		Not sure why, but we should find out and fix it.
+			fseek(s->file, 0, SEEK_END);
+			int amount_written = fwrite(s->buffer, sizeof(DataPoint), SENSOR_DATABUFSIZ, s->file);
+			if (amount_written != SENSOR_DATABUFSIZ)
+			{
+				Fatal("Wrote %d data points and expected to write %d to \"%s\" - %s", amount_written, SENSOR_DATABUFSIZ, strerror(errno));
+			}
+			//Log(LOGDEBUG, "Wrote %d data points for sensor %d", amount_written, s->id);
+		pthread_mutex_unlock(&(s->mutex));
+		// End of critical section
+
+		s->write_index = 0; // reset position in buffer
+		
+	}
+	Log(LOGDEBUG, "Thread for sensor %d exits", s->id);
+	return NULL; 
+}
+
+/**
+ * Fill buffer with most recent sensor data
+ * @param s - Sensor to use
+ * @param buffer - Buffer to fill
+ * @param bufsiz - Size of buffer to fill
+ * @returns The number of DataPoints actually read
+ */
+int Sensor_Query(Sensor * s, DataPoint * buffer, int bufsiz)
+{
+	int amount_read = 0;
+	//CRITICAL SECTION (Don't access file while sensor thread is writing to it!)
+	pthread_mutex_lock(&(s->mutex));
+		
+		fseek(s->file, -bufsiz*sizeof(DataPoint), SEEK_END);
+		amount_read = fread(buffer, sizeof(DataPoint), bufsiz, s->file);
+		//Log(LOGDEBUG, "Read %d data points", amount_read);		
+	pthread_mutex_unlock(&(s->mutex));
+	return amount_read;
+}
+
+/**
+ * Get a Sensor given an ID string
+ * @param id_str ID string
+ * @returns Sensor* identified by the string; NULL on error
+ */
+Sensor * Sensor_Identify(const char * id_str)
+{
+	char * end;
+	// Parse string as integer
+	int id = strtol(id_str, &end, 10);
+	if (*end != '\0')
+	{
+		return NULL;
+	}
+	// Bounds check
+	if (id < 0 || id >= NUMSENSORS)
+		return NULL;
+
+
+	Log(LOGDEBUG, "Sensor \"%s\" identified", g_sensor_names[id]);
+	return g_sensors+id;
+}
+
+/**
+ * Handle a request to the sensor module
+ * @param context - The context to work in
+ * @param params - Parameters passed
+ */
+void Sensor_Handler(FCGIContext *context, char * params)
+{
+	DataPoint buffer[SENSOR_QUERYBUFSIZ];
+	StatusCodes status = STATUS_OK;
+
+	enum {DEFAULT, DUMP} operation = DEFAULT;
+
+	const char * key; const char * value;
+
+	Sensor * sensor = NULL;
+
+	while ((params = FCGI_KeyPair(params, &key, &value)) != NULL)
+	{
+		Log(LOGDEBUG, "Got key=%s and value=%s", key, value);
+		if (strcmp(key, "id") == 0)
+		{
+			if (sensor != NULL)
+			{
+				Log(LOGERR, "Only one sensor id should be specified");
+				status = STATUS_ERROR;
+				break;
+			}
+			if (*value == '\0')
+			{
+				Log(LOGERR, "No id specified.");
+				status = STATUS_ERROR;
+				break;
+			}
+
+			sensor = Sensor_Identify(value);
+			if (sensor == NULL)
+			{
+				Log(LOGERR, "Invalid sensor id: %s", value);
+				status = STATUS_ERROR;
+				break;
+			}
+		}
+		else if (strcmp(key, "dump") == 0)
+		{
+			if (operation != DEFAULT)
+			{
+				Log(LOGERR, "Operation already specified!");
+				status = STATUS_ERROR;
+				break;
+			}
+			operation = DUMP;
+		}
+		else
+		{
+			Log(LOGERR, "Unknown key \"%s\" (value = %s)", key, value);
+			status = STATUS_ERROR;
+			break;
+		}		
+	}
+
+	if (status != STATUS_ERROR && sensor == NULL)
+	{
+		Log(LOGERR, "No valid sensor id given");
+		status = STATUS_ERROR;
+	}
+
+	if (status == STATUS_ERROR)
+	{
+		FCGI_RejectJSON(context);
+		return;
+	}
+	
+	switch (operation)
+	{
+		case DUMP:
+		{
+			FCGI_PrintRaw("Content-type: text/plain\r\n\r\n");
+			//CRITICAL SECTION
+			pthread_mutex_lock(&(sensor->mutex));
+				fseek(sensor->file, 0, SEEK_SET);
+				int amount_read = 0;
+				do
+				{
+					amount_read = fread(buffer, sizeof(DataPoint), SENSOR_QUERYBUFSIZ, sensor->file);
+					for (int i = 0; i < amount_read; ++i)
+					{
+						FCGI_PrintRaw("%f\t%f\n", buffer[i].time_stamp, buffer[i].value);
+					}
+	
+				}
+				while (amount_read == SENSOR_QUERYBUFSIZ);
+			pthread_mutex_unlock(&(sensor->mutex));
+			// end critical section
+			break;
+		}
+		default:
+		{
+			FCGI_BeginJSON(context, status);	
+			FCGI_JSONPair(key, value); // should spit back sensor ID
+			//Log(LOGDEBUG, "Call Sensor_Query...");
+			int amount_read = Sensor_Query(sensor, buffer, SENSOR_QUERYBUFSIZ);
+			//Log(LOGDEBUG, "Read %d DataPoints", amount_read);
+			//Log(LOGDEBUG, "Produce JSON response");
+			FCGI_JSONKey("data");
+			FCGI_JSONValue("[");
+			for (int i = 0; i < amount_read; ++i)
+			{
+				//TODO: Consider; is it better to give both tv_sec and tv_usec to the client seperately, instead of combining here?
+				
+				FCGI_JSONValue("[%f, %f]", buffer[i].time_stamp, buffer[i].value);
+				if (i+1 < amount_read)
+					FCGI_JSONValue(",");
+			}
+			FCGI_JSONValue("]");
+			//Log(LOGDEBUG, "Done producing JSON response");
+			FCGI_EndJSON();	
+			break;
+		}
+	}
+}
+
+/**
+ * Setup Sensors, start Sensor polling thread(s)
+ */
+void Sensor_Spawn()
+{
+	// start sensor threads
+	for (int i = 0; i < NUMSENSORS; ++i)
+	{
+		Init(g_sensors+i, i);
+		pthread_create(&(g_sensors[i].thread), NULL, Sensor_Main, (void*)(g_sensors+i));
+	}
+}
+
+/**
+ * Quit Sensor loops
+ */
+void Sensor_Join()
+{
+	if (!Thread_Runstate())
+	{
+		Fatal("This function should not be called before Thread_QuitProgram");
+	}
+	for (int i = 0; i < NUMSENSORS; ++i)
+	{
+		pthread_join(g_sensors[i].thread, NULL);
+		Destroy(g_sensors+i);
+	}
+}