X-Git-Url: https://git.ucc.asn.au/?a=blobdiff_plain;ds=sidebyside;f=server%2Fsensor.c;h=34c931097b567e6fd108f3f45fb317fc99afc574;hb=58361c992e9ac1644e3848f0c1d788741b538429;hp=ab687afdf5ecee1c75293888ad592fcdca0925a7;hpb=ab0ae45f79caaae86b36f8230f9399138c9e73bc;p=matches%2FMCTX3420.git diff --git a/server/sensor.c b/server/sensor.c index ab687af..34c9310 100644 --- a/server/sensor.c +++ b/server/sensor.c @@ -5,39 +5,48 @@ */ - +#include "common.h" #include "sensor.h" -#include "log.h" #include +/** Array of sensors, initialised by Sensor_Init **/ +static Sensor g_sensors[NUMSENSORS]; //global to this file + /** * Read a data value from a sensor; block until value is read * @param sensor_id - The ID of the sensor - * @returns The current value of the sensor + * @param d - DataPoint to set + * @returns NULL on error, otherwise d */ -DataPoint GetData(int sensor_id) +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 - DataPoint d; - //TODO: Deal with time stamps properly - static int count = 0; - d.time = count++; + + //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 + gettimeofday(&(d->time_stamp), NULL); + switch (sensor_id) { case SENSOR_TEST0: - d.value = count; + { + static int count = 0; + d->value = count++; break; + } case SENSOR_TEST1: - d.value = (float)(rand() % 100) / 100; + d->value = (float)(rand() % 100) / 100; break; default: Fatal("Unknown sensor id: %d", sensor_id); break; } usleep(100000); // simulate delay in sensor polling + return d; } @@ -58,16 +67,15 @@ void Destroy(Sensor * s) * Initialise a sensor * @param s - Sensor to initialise */ -void Sensor_Init(Sensor * s, int id) +void Init(Sensor * s, int id) { s->write_index = 0; s->read_offset = 0; s->id = id; - #define FILENAMESIZE BUFSIZ + #define FILENAMESIZE 3 char filename[FILENAMESIZE]; - //if (s->id >= pow(10, FILENAMESIZE)) - if (false) + if (s->id >= pow(10, FILENAMESIZE)) { Fatal("Too many sensors! FILENAMESIZE is %d; increase it and recompile.", FILENAMESIZE); } @@ -82,6 +90,9 @@ void Sensor_Init(Sensor * s, int id) } + + + /** * Run the main sensor polling loop * @param arg - Cast to Sensor* - Sensor that the thread will handle @@ -91,7 +102,7 @@ void * Sensor_Main(void * arg) { Sensor * s = (Sensor*)(arg); - while (true) //TODO: Exit condition + 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. @@ -103,7 +114,11 @@ void * Sensor_Main(void * arg) while (s->write_index < SENSOR_DATABUFSIZ) { - s->buffer[s->write_index] = GetData(s->id); + DataPoint * d = &(s->buffer[s->write_index]); + if (GetData(s->id, d) == NULL) + { + Fatal("Error collecting data"); + } s->write_index += 1; } @@ -111,6 +126,8 @@ void * Sensor_Main(void * arg) // 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) @@ -124,7 +141,8 @@ void * Sensor_Main(void * arg) s->write_index = 0; // reset position in buffer } - return NULL; + Log(LOGDEBUG, "Thread for sensor %d exits", s->id); + return NULL; } /** @@ -147,4 +165,135 @@ int Sensor_Query(Sensor * s, DataPoint * buffer, int bufsiz) 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; + + 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; + 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 + { + 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); + } + else + { + + 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? + //NOTE: Must always use doubles; floats get rounded! + double time = buffer[i].time_stamp.tv_sec + 1e-6*(buffer[i].time_stamp.tv_usec); + FCGI_JSONValue("[%f, %f]", time, buffer[i].value); + if (i+1 < amount_read) + FCGI_JSONValue(","); + } + FCGI_JSONValue("]"); + //Log(LOGDEBUG, "Done producing JSON response"); + FCGI_EndJSON(); + } +} + +/** + * 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); + } +}