X-Git-Url: https://git.ucc.asn.au/?a=blobdiff_plain;f=server%2Fsensor.c;h=34c931097b567e6fd108f3f45fb317fc99afc574;hb=cf310248b767630a93e81f9cd9cd3700d0d45cb5;hp=622251054fb52dfedf04984cd20761f6b81d8c5c;hpb=7ca215713fa73c84ba0b46c9e7299386bd5cf5b8;p=matches%2FMCTX3420.git diff --git a/server/sensor.c b/server/sensor.c index 6222510..34c9310 100644 --- a/server/sensor.c +++ b/server/sensor.c @@ -9,34 +9,44 @@ #include "sensor.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; } @@ -57,16 +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); } @@ -81,6 +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 @@ -90,7 +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. @@ -102,7 +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; } @@ -110,6 +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) @@ -123,7 +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; } /** @@ -146,6 +165,27 @@ 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 @@ -157,15 +197,14 @@ void Sensor_Handler(FCGIContext *context, char * params) StatusCodes status = STATUS_OK; const char * key; const char * value; - int sensor_id = SENSOR_NONE; + 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) { - char *end; - if (sensor_id != SENSOR_NONE) + if (sensor != NULL) { Log(LOGERR, "Only one sensor id should be specified"); status = STATUS_ERROR; @@ -177,11 +216,11 @@ void Sensor_Handler(FCGIContext *context, char * params) status = STATUS_ERROR; break; } - //TODO: Use human readable sensor identifier string for API? - sensor_id = strtol(value, &end, 10); - if (*end != '\0') + + sensor = Sensor_Identify(value); + if (sensor == NULL) { - Log(LOGERR, "Sensor id not an integer; %s", value); + Log(LOGERR, "Invalid sensor id: %s", value); status = STATUS_ERROR; break; } @@ -194,14 +233,9 @@ void Sensor_Handler(FCGIContext *context, char * params) } } - if (sensor_id == SENSOR_NONE) - { - Log(LOGERR, "No sensor id specified"); - status = STATUS_ERROR; - } - else if (sensor_id >= NUMSENSORS || sensor_id < 0) + if (status != STATUS_ERROR && sensor == NULL) { - Log(LOGERR, "Invalid sensor id %d", sensor_id); + Log(LOGERR, "No valid sensor id given"); status = STATUS_ERROR; } @@ -211,17 +245,21 @@ void Sensor_Handler(FCGIContext *context, char * params) } else { + FCGI_BeginJSON(context, status); FCGI_JSONPair(key, value); // should spit back sensor ID //Log(LOGDEBUG, "Call Sensor_Query..."); - int amount_read = Sensor_Query(&(g_sensors[sensor_id]), buffer, SENSOR_QUERYBUFSIZ); + 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) { - FCGI_JSONValue("[%f, %f]", buffer[i].time, buffer[i].value); + //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(","); } @@ -230,3 +268,32 @@ void Sensor_Handler(FCGIContext *context, char * params) 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); + } +}