Route output from backend through frontend

ethermess-backend.c

@@ -1049,7 +1049,8 @@ void eventloop(void) {
 				// Read a command
 				read_command();
 			} else if (pollfds[0].revents & POLLHUP) {
-				// Quit
+				// Quit on frontend exiting
+				warnx("Frontend exited unexpectedly");
 				running = false;
 			} else {
 				errx(1, "Got poll event %hd on stdin\n", pollfds[0].revents);
@@ -1063,6 +1064,9 @@ void eventloop(void) {
 			if (pollfds[1].revents & POLLIN) {
 				// Process a frame
 				process_frame();
+			} else if (pollfds[1].revents & POLLERR) {
+				// Lost connection
+				errx(1, "Network went down");
 			} else {
 				errx(1, "Got poll event %hd on packet socket\n", pollfds[1].revents);
 			}
@@ -1121,13 +1125,8 @@ int main(int argc, char **argv) {
 	memcpy(own_mac, ifr.ifr_hwaddr.sa_data, sizeof(own_mac));
 
 	// Print it out
-	char own_mac_str[18];
-	format_mac(own_mac, own_mac_str);
-	if (printf("%s\n", own_mac_str) == -1) {
-		err(1, "printf");
-	}
-	if (fflush(stdout) == EOF) {
-		err(1, "fflush");
+	if (write(1, own_mac, 6) != 6) {
+		err(1, "write");
 	}
 
 	// Initialize the message id cache

ethermess.py

@@ -73,6 +73,15 @@ def writeall(f, b):
 	while written < len(b):
 		written += f.write(b[written:])
 
+def readall(f, length):
+	read = bytearray()
+	while len(read) < length:
+		data = f.read(length - len(read))
+		if data is None:
+			raise ConnectionError('Could not satisfy read of %i bytes' % length)
+		read.extend(data)
+	return bytes(read)
+
 def parse_mac(text):
 	parts = text.split(':')
 	if len(parts) != 6:
@@ -85,19 +94,34 @@ def parse_mac(text):
 
 	return parsed
 
+def format_mac(mac):
+	return ':'.join(mac[i:i+1].hex() for i in range(len(mac)))
+
 class PollBasedThread(threading.Thread):
 	def run(self):
-		poll = select.poll()
-		for f in self.pollin:
-			poll.register(f, select.POLLIN)
+		while True:
+			restart = False
+			self.initialize()
 
-		self.initialize()
+			poll = select.poll()
+			for f in self.pollin:
+				poll.register(f, select.POLLIN)
 
-		running = True
-		while running:
-			for fd, event in poll.poll():
-				if self.poll_loop(fd, event) != None:
-					running = False
+			running = True
+			while running and not restart:
+				for fd, event in poll.poll():
+					command = self.poll_loop(fd, event)
+					if command == None:
+						pass
+					elif command == 'quit':
+						running = False
+					elif command == 'restart':
+						restart = True
+					else:
+						raise ValueError("poll_loop() needs to return either None, 'quit', or 'restart'")
+
+			if not restart:
+				break
 
 		self.finalize()
 
@@ -111,15 +135,26 @@ class PollBasedThread(threading.Thread):
 		...
 
 class Backend(PollBasedThread):
-	def __init__(self, interface, writes_channel, control_channel):
+	def __init__(self, interface, nick, writes_channel, control_channel):
 		self.interface = interface
+		self.nick = nick
 		self.writes_channel = writes_channel
 		self.control_channel = control_channel
-		self.pollin = [self.writes_channel, self.control_channel]
 		super().__init__()
 
 	def initialize(self):
-		self.proc = subprocess.Popen(['sudo', libexec_dir + '/ethermess-backend', self.interface], stdin = subprocess.PIPE, stdout = sys.stdout, stderr = sys.stderr, bufsize = 0)
+		self.proc = subprocess.Popen(['sudo', libexec_dir + '/ethermess-backend', self.interface], stdin = subprocess.PIPE, stdout = subprocess.PIPE, stderr = sys.stderr, bufsize = 0)
+		self.pollin = [self.writes_channel, self.control_channel, self.proc.stdout]
+
+		# Tell the backend the status and nick
+		status = 0
+		nick = self.nick.encode('utf-8')
+		writeall(self.proc.stdin, bytes([status, len(nick)]) + nick)
+
+		# Read our MAC
+		self.mac = readall(self.proc.stdout, 6)
+
+		print('Own mac: %s' % format_mac(self.mac))
 
 	def poll_loop(self, fd, event):
 		if fd == self.writes_channel.fileno() and event & select.POLLIN:
@@ -134,6 +169,15 @@ class Backend(PollBasedThread):
 			else:
 				raise Exception('Unreachable')
 
+		elif fd == self.proc.stdout.fileno() and event & select.POLLIN:
+			data = self.proc.stdout.read(1024)
+			sys.stdout.buffer.write(data)
+			sys.stdout.flush()
+
+		elif fd == self.proc.stdout.fileno() and event & select.POLLHUP:
+			print('Backend exited')
+			return 'quit'
+
 		else:
 			raise Exception('Unreachable')
 
@@ -183,8 +227,5 @@ control_channel = Channel()
 
 _, interface, nick = sys.argv
 
-nick = nick.encode('utf-8')
-writes_channel.send((bytes([0, len(nick)]) + nick))
-
-Backend(interface, writes_channel, control_channel).start()
+Backend(interface, nick, writes_channel, control_channel).start()
 Input(writes_channel, control_channel).start()