Add explanatory comments above each major block in main.c

main.c

@@ -37,6 +37,13 @@ int main(int argc, char *argv[])
 	(void)argc;
 	(void)argv;
 
+	/*
+	 * Register signal handler for SIGTERM and SIGINT.
+	 *
+	 * The behaviour of signal() is not entirely consistent across
+	 * different implementations, so this should ideally be rewritten
+	 * to use signaction() instead at some point.
+	 */
 	if (signal(SIGTERM, handle_exit_signal) == SIG_ERR) {
 		fprintf(stderr, "Failed to register SIGTERM signal handler\n");
 		return 1;
@@ -46,12 +53,18 @@ int main(int argc, char *argv[])
 		return 1;
 	}
 
+	/*
+	 * Initialise socket.
+	 *
+	 * Currently only supporting IPv6, and hard-coding address and
+	 * port. Should eventully get address and port from arguments, and
+	 * support IPv4 as well.
+	 */
 	int sfd = socket(AF_INET6, SOCK_STREAM, 0);
 	if (sfd == -1) {
 		fprintf(stderr, "Failed to open socket\n");
 		return 1;
 	}
-
 	const struct sockaddr_in6 haddr = {
 		.sin6_family = AF_INET6,
 		.sin6_port = htons(7070),
@@ -70,6 +83,13 @@ int main(int argc, char *argv[])
 	socklen_t paddr_size = sizeof(paddr);
 	int cfd;
 	while (!exit_requested) {
+		/*
+		 * Accept incoming connection.
+		 *
+		 * If accept() returns with an error and errno is EINTR, this
+		 * should not exit the program as it just indicates that a
+		 * signal arrived while waiting for a connection.
+		 */
 		cfd = accept(sfd, (struct sockaddr *)&paddr, &paddr_size);
 		if (cfd == -1) {
 			if (errno == EINTR)