Start reading thread right after program start

Program state can be changed from both threads now and
'state->prog_state' modification is protected with mutex

camogm.c

@@ -215,6 +215,7 @@ void camogm_init(camogm_state *state, char *pipe_name)
 	state->exif = DEFAULT_EXIF;
 	state->frame_lengths = NULL;
 
+	// reading thread has not been started yet, mutex lock is not necessary
 	state->prog_state = STATE_STOPPED;
 
 	// kml stuff
@@ -312,7 +313,9 @@ int camogm_start(camogm_state *state)
 	}
 	state->max_frames =       state->set_max_frames;
 	state->frames_per_chunk = state->set_frames_per_chunk;
+	pthread_mutex_lock(&state->mutex);
 	state->prog_state = STATE_STARTING;
+	pthread_mutex_unlock(&state->mutex);
 	FOR_EACH_PORT(int, chn) {
 		//! Check/set circbuf read pointer
 		D3(fprintf(debug_file, "1: state->cirbuf_rp=0x%x\n", state->cirbuf_rp[chn]));
@@ -453,7 +456,9 @@ int camogm_start(camogm_state *state)
 	}
 	if (state->kml_enable) rslt = camogm_start_kml(state);  // will turn on state->kml_used if it can
 	if (rslt) return rslt;
+	pthread_mutex_lock(&state->mutex);
 	state->prog_state = STATE_RUNNING;
+	pthread_mutex_unlock(&state->mutex);
 	D1(fprintf(debug_file, "Started OK\n"));
 	return 0;
 }
@@ -656,7 +661,9 @@ int camogm_stop(camogm_state *state)
 		if (state->prog_state != STATE_STARTING) {
 			D2(fprintf(debug_file, "Recording was not running, nothing to stop\n"));
 		} else {
+			pthread_mutex_lock(&state->mutex);
 			state->prog_state = STATE_STOPPED;
+			pthread_mutex_unlock(&state->mutex);
 			D1(fprintf(debug_file, "Dropping attempt to start\n"));
 		}
 		return 0;
@@ -675,7 +682,9 @@ int camogm_stop(camogm_state *state)
 	state->vf = NULL;
 	if (rslt) return rslt;
 	state->last = 1;
+	pthread_mutex_lock(&state->mutex);
 	state->prog_state = STATE_STOPPED;
+	pthread_mutex_unlock(&state->mutex);
 	return 0;
 }
 
@@ -1331,20 +1340,14 @@ int parse_cmd(camogm_state *state, FILE* npipe)
 			state->rawdev.rawdev_path[0] = '\0';
 		}
 		return 28;
-	} else if (strcmp(cmd, "rawdev_read") == 0) {
-		if (state->rawdev_op && state->prog_state == STATE_STOPPED) {
-			state->prog_state = STATE_READING;
-		} else {
-			D0(fprintf(debug_file, "Unable to switch state to 'reading' from current state. Check settings.\n"));
-		}
-		return 29;
-	} else if (strcmp(cmd, "rawdev_stop") == 0) {
-		if (state->prog_state == STATE_READING) {
+	} else if (strcmp(cmd, "reader_stop") == 0) {
+		if (state->prog_state == STATE_READING &&
+				state->rawdev.thread_state == STATE_RUNNING) {
 			state->rawdev.thread_state = STATE_CANCEL;
 		} else {
 			D0(fprintf(debug_file, "Reading thread is not running, nothing to stop\n"));
 		}
-		return 30;
+		return 29;
 	}
 
 	return -1;
@@ -1380,7 +1383,6 @@ void clean_up(camogm_state *state)
  */
 int listener_loop(camogm_state *state)
 {
-	void *tret;
 	FILE *cmd_file;
 	int rslt, ret, cmd, f_ok;
 	int fp0, fp1;
@@ -1495,35 +1497,9 @@ int listener_loop(camogm_state *state)
 			} // switch camogm_start()
 			if ((rslt != 0) && (rslt != CAMOGM_TOO_EARLY) && (rslt != CAMOGM_FRAME_NOT_READY) && (rslt != CAMOGM_FRAME_CHANGED) ) state->last_error_code = rslt;
 		} else if (state->prog_state == STATE_READING) {
-			if (state->rawdev.thread_state == STATE_RUNNING) {
-				if (state->rawdev.thread_finished == true) {
-					state->rawdev.thread_state = STATE_STOPPED;
-					state->rawdev.thread_finished = false;
-					state->prog_state = STATE_STOPPED;
-					pthread_join(state->rawdev.tid, &tret);
-					if ((int)tret != 0 && (int)tret != (int)PTHREAD_CANCELED) {
-						D0(fprintf(debug_file, "Reading thread returned error %d\n", (int)tret));
-					} else {
-						D3(fprintf(debug_file, "Reading thread stopped\n"));
-					}
-				} else {
-					usleep(COMMAND_LOOP_DELAY);
-				}
-			} else if (state->rawdev.thread_state == STATE_STOPPED) {
-				state->rawdev.thread_state = STATE_RUNNING;
-				state->rawdev.thread_finished = false;
-//				if (pthread_create(&state->rawdev.tid, NULL, build_index, state) != 0) {
-				if (pthread_create(&state->rawdev.tid, NULL, reader, state) != 0) {
-					state->prog_state = STATE_STOPPED;
-					state->rawdev.thread_state = STATE_STOPPED;
-					D0(fprintf(debug_file, "%s:line %d: Can not start new thread, disk index is not built\n", __FILE__, __LINE__));
-				}
-			} else if (state->rawdev.thread_state == STATE_CANCEL) {
-				// cancel reading thread and return to running state waiting for the thread to terminate
-				state->rawdev.thread_state = STATE_RUNNING;
-				pthread_cancel(state->rawdev.tid);
-			}
+			usleep(COMMAND_LOOP_DELAY);
 		} else {                            // not running, not starting
+			state->rawdev.thread_state = STATE_RUNNING;
 			usleep(COMMAND_LOOP_DELAY);     // make it longer but interruptible by signals?
 		}
 	} // while (process)
@@ -1683,7 +1659,7 @@ int open_files(camogm_state *state)
 		}
 		framePars[port] = frameParsAll[port]->framePars;
 		aglobalPars[port] = frameParsAll[port]->globalPars;
-#endif /* DESABLE_CODE */
+#endif /* DISABLE_CODE */
 	}
 
 	return ret;
@@ -1718,9 +1694,20 @@ int main(int argc, char *argv[])
 	}
 
 	camogm_init(&sstate, argv[1]);
+	if (pthread_mutex_init(&sstate.mutex, NULL) != 0) {
+		perror("Unable to initialize mutex\n");
+		return EXIT_FAILURE;
+	}
 	ret = open_files(&sstate);
 	if (ret < 0)
 		return ret;
+	if (pthread_create(&sstate.rawdev.tid, NULL, reader, &sstate) != 0 ||
+			pthread_detach(sstate.rawdev.tid) != 0) {
+		D0(fprintf(debug_file, "%s:line %d: Can not start reading thread in detached state\n", __FILE__, __LINE__));
+		clean_up(&sstate);
+		return EXIT_FAILURE;
+	}
+	sstate.rawdev.thread_state = STATE_RUNNING;
 
 	ret = listener_loop(&sstate);
 

camogm.h

@@ -107,8 +107,7 @@ typedef struct {
 	volatile uint64_t curr_pos_r;
 	uint64_t file_start;
 	pthread_t tid;
-	int thread_state;
-	volatile bool thread_finished;
+	volatile int thread_state;
 } rawdev_buffer;
 
 /**
@@ -137,7 +136,8 @@ typedef struct {
 	int frame_period[SENSOR_PORTS];                         ///< in microseconds (1/10 of what is needed for the Ogm header)
 	int width;                                              ///< image width
 	int height;                                             ///< image height
-	int prog_state;                                         ///< program state flag, can be one of #state_flags
+	volatile int prog_state;                                ///< program state flag, can be one of #state_flags
+	pthread_mutex_t mutex;                                  ///< mutex for @e prog_state variable; all modifications to the variable must be using this mutex
 	int last_error_code;
 	ogg_stream_state os;
 	ogg_page og;

camogm_read.c

@@ -942,10 +942,19 @@ void *reader(void *arg)
 		fd = accept(sockfd, NULL, 0);
 		if (fd == -1)
 			continue;
+		if (state->prog_state == STATE_STOPPED && state->rawdev_op) {
+			pthread_mutex_lock(&state->mutex);
+			state->prog_state = STATE_READING;
+			pthread_mutex_unlock(&state->mutex);
+		} else {
+			close(fd);
+			D0(fprintf(debug_file, "Can not change state of the program, check settings\n"));
+			continue;
+		}
 		cmd_len = read(fd, cmd_buff, sizeof(cmd_buff) - 1);
 		cmd_ptr = cmd_buff;
 		trim_command(cmd_ptr, cmd_len);
-		while ((cmd = parse_command(&cmd_ptr)) != -2) {
+		while ((cmd = parse_command(&cmd_ptr)) != -2 && state->rawdev.thread_state != STATE_CANCEL) {
 			if (cmd >= 0)
 				D6(fprintf(debug_file, "Got command '%s', number %d\n", cmd_list[cmd], cmd));
 			switch (cmd) {
@@ -984,7 +993,7 @@ void *reader(void *arg)
 				mm_file_size = rawdev->mmap_default_size - rawdev->start_pos;
 				send_fnum(fd, disk_chunks);
 				close(fd);
-				while (disk_chunks > 0 && transfer) {
+				while (disk_chunks > 0 && transfer && state->rawdev.thread_state != STATE_CANCEL) {
 					fd = accept(sockfd, NULL, 0);
 					if (mmap_disk(rawdev, &mmap_range) == 0) {
 						send_buffer(fd, &rawdev->disk_mmap[mm_file_start], mm_file_size);
@@ -1041,7 +1050,7 @@ void *reader(void *arg)
 					cross_boundary_indx = NULL;
 					file_cntr = 0;
 					transfer = true;
-					while (file_cntr < index_dir.size && disk_indx != NULL) {
+					while (file_cntr < index_dir.size && disk_indx != NULL && state->rawdev.thread_state != STATE_CANCEL) {
 						if (is_in_range(&mmap_range, disk_indx) && rawdev->disk_mmap != NULL) {
 							fd = accept(sockfd, NULL, 0);
 							mm_file_start = disk_indx->f_offset - rawdev->mmap_offset;
@@ -1090,6 +1099,9 @@ void *reader(void *arg)
 		}
 		if (fstat(fd, &stat_buff) != EBADF)
 			close(fd);
+		pthread_mutex_lock(&state->mutex);
+		state->prog_state = STATE_STOPPED;
+		pthread_mutex_unlock(&state->mutex);
 		usleep(COMMAND_LOOP_DELAY);
 	}
 	pthread_cleanup_pop(0);
@@ -1114,7 +1126,6 @@ static inline void exit_thread(void *arg)
 		close(*s->sockfd_const);
 	if (fstat(*s->sockfd_temp, &buff) != EBADF)
 		close(*s->sockfd_temp);
-	s->state->rawdev.thread_finished = true;
 }
 
 /**
@@ -1171,7 +1182,7 @@ void build_index(camogm_state *state, struct disk_idir *idir)
 	zero_cross = 0;
 	search_state = SEARCH_SKIP;
 	idir_result = 0;
-	while (process) {
+	while (process && state->rawdev.thread_state != STATE_CANCEL) {
 		rd = read(state->rawdev.rawdev_fd, buff, sizeof(buff));
 		err = errno;
 		if ((rd > 0) && (dev_curr_pos + rd > state->rawdev.end_pos)) {