[tarantool-patches] [PATCH 5/6] test: differentiate blocked and closed swim fake fds

[Vladislav Shpilevoy <v.shpilevoy@tarantool.org>]

SWIM's fake file descriptors were implemented to test SWIM with
virtual time and fully controlled network with immediate packet
delivery. One of their features - API to block a file descriptor
and test various failures about it.

But blocked fake fd looks the same as closed fd, and it can
confuse new test's author. Now if an fd is not unblocked at the
end of a test, it leads to a crash. This commit fixes that via
adding explicit difference between blocked and closed fd.

Part of #3234
---
 test/unit/swim_test_transport.c | 53 +++++++++++++++++++++------------
 1 file changed, 34 insertions(+), 19 deletions(-)

diff --git a/test/unit/swim_test_transport.c b/test/unit/swim_test_transport.c
index d6591e969..d1c3e97d7 100644
--- a/test/unit/swim_test_transport.c
+++ b/test/unit/swim_test_transport.c
@@ -90,10 +90,17 @@ struct swim_fd {
 	/** File descriptor number visible to libev. */
 	int evfd;
 	/**
-	 * Link in the list of opened descriptors. Used to feed
-	 * them all EV_WRITE.
+	 * True, if the descriptor is opened and can receive new
+	 * messages. Regardless of blocked or not. In case of
+	 * blocked, new messages are queued, but not delivered.
 	 */
-	struct rlist in_opened;
+	bool is_opened;
+
+	/**
+	 * Link in the list of opened and non-blocked descriptors.
+	 * Used to feed them all EV_WRITE.
+	 */
+	struct rlist in_active;
 	/** Queue of received, but not processed packets. */
 	struct rlist recv_queue;
 	/** Queue of sent, but not received packets. */
@@ -103,23 +110,22 @@ struct swim_fd {
 /** Table of fake file descriptors. */
 static struct swim_fd swim_fd[FAKE_FD_NUMBER];
 /**
- * List of opened file descriptors. Used to avoid fullscan of the
+ * List of active file descriptors. Used to avoid fullscan of the
  * table.
  */
-static RLIST_HEAD(swim_fd_opened);
+static RLIST_HEAD(swim_fd_active);
 
 /** Open a fake file descriptor. */
 static inline int
 swim_fd_open(struct swim_fd *fd)
 {
-	if (! rlist_empty(&fd->in_opened)) {
+	if (fd->is_opened) {
 		errno = EADDRINUSE;
 		diag_set(SocketError, "test_socket:1", "bind");
 		return -1;
 	}
-	rlist_add_tail_entry(&swim_fd_opened, fd, in_opened);
-	rlist_create(&fd->recv_queue);
-	rlist_create(&fd->send_queue);
+	fd->is_opened = true;
+	rlist_add_tail_entry(&swim_fd_active, fd, in_active);
 	return 0;
 }
 
@@ -127,12 +133,15 @@ swim_fd_open(struct swim_fd *fd)
 static inline void
 swim_fd_close(struct swim_fd *fd)
 {
+	if (! fd->is_opened)
+		return;
 	struct swim_test_packet *i, *tmp;
 	rlist_foreach_entry_safe(i, &fd->recv_queue, in_queue, tmp)
 		swim_test_packet_delete(i);
 	rlist_foreach_entry_safe(i, &fd->send_queue, in_queue, tmp)
 		swim_test_packet_delete(i);
-	rlist_del_entry(fd, in_opened);
+	rlist_del_entry(fd, in_active);
+	fd->is_opened = false;
 }
 
 void
@@ -140,7 +149,8 @@ swim_test_transport_init(void)
 {
 	for (int i = 0, evfd = FAKE_FD_BASE; i < FAKE_FD_NUMBER; ++i, ++evfd) {
 		swim_fd[i].evfd = evfd;
-		rlist_create(&swim_fd[i].in_opened);
+		swim_fd[i].is_opened = false;
+		rlist_create(&swim_fd[i].in_active);
 		rlist_create(&swim_fd[i].recv_queue);
 		rlist_create(&swim_fd[i].send_queue);
 	}
@@ -172,6 +182,7 @@ swim_transport_send(struct swim_transport *transport, const void *data,
 		swim_test_packet_new(data, size, &transport->addr,
 				     (const struct sockaddr_in *) addr);
 	struct swim_fd *src = &swim_fd[transport->fd - FAKE_FD_BASE];
+	assert(src->is_opened);
 	rlist_add_tail_entry(&src->send_queue, p, in_queue);
 	return size;
 }
@@ -188,6 +199,7 @@ swim_transport_recv(struct swim_transport *transport, void *buffer, size_t size,
 	 * Pop a packet from a receving queue.
 	 */
 	struct swim_fd *dst = &swim_fd[transport->fd - FAKE_FD_BASE];
+	assert(dst->is_opened);
 	struct swim_test_packet *p =
 		rlist_shift_entry(&dst->recv_queue, struct swim_test_packet,
 				  in_queue);
@@ -236,16 +248,16 @@ void
 swim_test_transport_block_fd(int fd)
 {
 	struct swim_fd *sfd = &swim_fd[fd - FAKE_FD_BASE];
-	assert(! rlist_empty(&sfd->in_opened));
-	rlist_del_entry(sfd, in_opened);
+	assert(! rlist_empty(&sfd->in_active));
+	rlist_del_entry(sfd, in_active);
 }
 
 void
 swim_test_transport_unblock_fd(int fd)
 {
 	struct swim_fd *sfd = &swim_fd[fd - FAKE_FD_BASE];
-	assert(rlist_empty(&sfd->in_opened));
-	rlist_add_tail_entry(&swim_fd_opened, sfd, in_opened);
+	if (sfd->is_opened && rlist_empty(&sfd->in_active))
+		rlist_add_tail_entry(&swim_fd_active, sfd, in_active);
 }
 
 /** Send one packet to destination's recv queue. */
@@ -257,8 +269,11 @@ swim_fd_send_packet(struct swim_fd *fd)
 	struct swim_test_packet *p =
 		rlist_shift_entry(&fd->send_queue, struct swim_test_packet,
 				  in_queue);
-	int dst_i = ntohs(p->dst.sin_port);
-	rlist_add_tail_entry(&swim_fd[dst_i].recv_queue, p, in_queue);
+	struct swim_fd *dst = &swim_fd[ntohs(p->dst.sin_port)];
+	if (dst->is_opened)
+		rlist_add_tail_entry(&dst->recv_queue, p, in_queue);
+	else
+		swim_test_packet_delete(p);
 }
 
 void
@@ -269,11 +284,11 @@ swim_transport_do_loop_step(struct ev_loop *loop)
 	 * Reversed because libev invokes events in reversed
 	 * order. So this reverse + libev reverse = normal order.
 	 */
-	rlist_foreach_entry_reverse(fd, &swim_fd_opened, in_opened) {
+	rlist_foreach_entry_reverse(fd, &swim_fd_active, in_active) {
 		swim_fd_send_packet(fd);
 		ev_feed_fd_event(loop, fd->evfd, EV_WRITE);
 	}
-	rlist_foreach_entry_reverse(fd, &swim_fd_opened, in_opened) {
+	rlist_foreach_entry_reverse(fd, &swim_fd_active, in_active) {
 		if (!rlist_empty(&fd->recv_queue))
 			ev_feed_fd_event(loop, fd->evfd, EV_READ);
 	}
-- 
2.17.2 (Apple Git-113)