sendbeacon: runforever or end after a beacon is successfully recieved

note the 0x15 is read from the serial console when beacon succeeds

sendbeacon/Makefile

+CFLAGS += -pthread
+LDLAGS += -pthread
+
 sendbeacon: sendbeacon.c
 

sendbeacon/sendbeacon.c

@@ -22,15 +22,22 @@
 #include <fcntl.h>
 #include <string.h>
 #include <stdio.h>
+#include <stdlib.h>
+#include <pthread.h>
 
+#define READ_BUFFER_SIZE 100
+#define VERIFY_LEN 20
+#define VERIFY_CHR 0x15
 #define error_message(args...) fprintf(stderr, args)
 
+static pthread_barrier_t barrier;
+
 int set_interface_attribs(int fd, int speed, int parity)
 {
 	struct termios tty;
 	memset(&tty, 0, sizeof tty);
 	if(tcgetattr(fd, &tty) != 0) {
-		error_message("error %d from tcgetattr", errno);
+		error_message("error %d from tcgetattr\n", errno);
 		return -1;
 	}
 
@@ -49,31 +56,92 @@ int set_interface_attribs(int fd, int speed, int parity)
 	tty.c_cflag &= ~CRTSCTS;
 
 	if(tcsetattr(fd, TCSANOW, &tty) != 0) {
-		error_message("error %d from tcsetattr", errno);
+		error_message("error %d from tcsetattr\n", errno);
 		return -1;
 	}
 	return 0;
 }
 
-void set_blocking(int fd, int block)
+void set_blocking(int fd, char block, char timeout)
 {
 	struct termios tty;
 	memset(&tty, 0, sizeof tty);
 	if(tcgetattr(fd, &tty) != 0) {
-		error_message("error %d from tggetattr", errno);
+		error_message("error %d from tggetattr\n", errno);
 		return;
 	}
 
-	tty.c_cc[VMIN] = block ? 1 : 0;
-	tty.c_cc[VTIME] = 5;
+	tty.c_cc[VMIN] = block;
+	tty.c_cc[VTIME] = timeout;
 
 	if(tcsetattr(fd, TCSANOW, &tty) != 0)
-		error_message("error %d setting term attributes", errno);
+		error_message("error %d setting term attributes\n", errno);
 }
 
 void print_usage()
 {
-	printf("usage: sendbeacon <serial_device> \n");
+	printf("usage: sendbeacon <serial_device>\n");
+}
+
+void * write_handler(void *ptr)
+{
+	char *path = (char *)ptr;
+	while (1) {
+		int fd = open(path, O_WRONLY | O_NOCTTY | O_SYNC);
+		if(fd < 0) {
+			error_message("error %d opening %s: %s\n", errno, path, strerror(errno));
+			return NULL;
+		}
+
+		set_interface_attribs(fd, B115200, 0);
+		set_blocking(fd, 0, 5);
+
+		// write for some time
+		char buf [8] = {0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77, 0xbb};
+		int i;
+		for (i = 0; i < 10000; i++) {
+			write(fd, buf, 8);
+		}
+		close(fd);
+
+		pthread_barrier_wait(&barrier);
+	}
+}
+
+void * read_handler(void *ptr)
+{
+	char *path = (char *)ptr;
+	char expected[VERIFY_LEN];
+	memset(expected, VERIFY_CHR, VERIFY_LEN);
+
+	while (1) {
+		int fd = open(path, O_RDONLY | O_NOCTTY | O_SYNC);
+		if(fd < 0) {
+			error_message("error %d opening %s: %s\n", errno, path, strerror(errno));
+			return NULL;
+		}
+
+		set_interface_attribs(fd, B115200, 0);
+		set_blocking(fd, VERIFY_LEN, 5);
+
+		char buffer[READ_BUFFER_SIZE];
+		int cnt = read(fd, buffer, sizeof buffer);
+		if (cnt) {
+			int i;
+			for (i = 0; i < cnt; ++i) {
+				printf("%02X", (unsigned char)buffer[i]);
+			}
+			printf("\n");
+			if (cnt == VERIFY_LEN) {
+				if (0 == memcmp(expected, buffer, VERIFY_LEN)) {
+					exit(0);
+				}
+			}
+		}
+		close(fd);
+
+		pthread_barrier_wait(&barrier);
+	}
 }
 
 int main(int argc, char **argv)
@@ -90,23 +158,32 @@ int main(int argc, char **argv)
 
 	char *portname = argv[1];
 
-	int fd = open(portname, O_RDWR | O_NOCTTY | O_SYNC);
-	if(fd < 0) {
-		error_message("error %d opening %s: %s", errno, portname, strerror(errno));
+	// init barrier
+	int res = pthread_barrier_init(&barrier, NULL, 2);
+	if (res != 0) {
+		error_message("pthread_barrier_init failed!\n");
 		return 1;
 	}
 
-	set_interface_attribs(fd, B115200, 0);
-	set_blocking(fd, 0);
+	// create worker threads
+	pthread_t write_thread;
+	res = pthread_create(&write_thread, NULL, write_handler, (void *) portname);
+	if (res != 0) {
+		error_message("failed to create write thread!\n");
+		return 1;
+	}
 
-	printf("Sending beacon in loop. You have 5-10 seconds to power up Omnia.\n");
+	pthread_t read_thread;
+	res = pthread_create(&read_thread, NULL, read_handler, (void *) portname);
+	if (res != 0) {
+		error_message("failed to create read thread!\n");
+		return 1;
+	}
 
-	char buf [8] = {0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77, 0xbb};
-	int i;
-	for(i=0; i<10000; i++)
-		write(fd, buf, 8);
-	close(fd);
+	pthread_join(write_thread, NULL);
+	pthread_join(read_thread, NULL);
 
-	return 0;
+	// this should not be reached if no error is triggered
+	return 1;
 }