io_tls: Mark connections as dead on POLLHUP.

Connections are already marked as dead on POLLNVAL, but this should
also be done on POLLHUP, to prevent looping indefinitely due to
continuing to service the session when we shouldn't, until
the application layer terminates a TLS session.

io/io_tls.c

@@ -288,6 +288,9 @@ static pthread_t ssl_thread;
 #define MARK_DEAD(s) \
 	RWLIST_TRAVERSE(&sslfds, sfd, entry) { \
 		if (sfd->ssl == s) { \
+			if (sfd->dead) { /* Shouldn't happen since we rebuild traversal list after MARK_DEAD */ \
+				bbs_warning("SSL connection %p already marked as dead?\n", sfd->ssl); \
+			} \
 			sfd->dead = 1; \
 			bbs_debug(5, "SSL connection %p now marked as dead\n", sfd->ssl); \
 			break; \
@@ -525,7 +528,7 @@ static void *ssl_io_thread(void *unused)
 				res--; /* Processed one event. Break the loop as soon as there are no more, to avoid traversing all like with select(). */
 			}
 			if (!inovertime && pfds[i].revents != POLLIN) { /* Something exceptional happened, probably something going away */
-				if (pfds[i].revents & POLLNVAL) {
+				if (pfds[i].revents & (POLLNVAL | POLLHUP)) {
 					SSL *ssl = ssl_list[i / 2];
 					bbs_debug(5, "Skipping SSL at index %d / %d = %s\n", i, i/2, poll_revent_name(pfds[i].revents));
 					MARK_DEAD(ssl);
@@ -669,7 +672,7 @@ static void *ssl_io_thread(void *unused)
 				SSL *ssl = ssl_list[(i - 1) / 2];
 				ores = (int) read(pfds[i].fd, buf, sizeof(buf));
 				if (ores <= 0) {
-					bbs_debug(3, "read returned %d\n", ores);
+					bbs_debug(3, "read returned %d on fd %d: %s\n", ores, pfds[i].fd, strerror(errno));
 					/* Application closed the connection,
 					 * but it will close the node fd (socket) so we don't need to close here. */
 					MARK_DEAD(ssl); /* What we can do now though is mark it as dead */