[PATCH mptcp-next v7 9/9] selftests: mptcp: connect: close listensock deterministically

From: Geliang Tang <[email protected]>

In main_loop_s(), listensock was closed nondeterministically inside
maybe_close() during the accept loop, and error paths closed it without
tracking, leading to double-close or leaks across repeated iterations
(via goto again).

Fix by making maybe_close() return a bool indicating whether it closed
the fd, and track that per iteration. Funnel poll/accept error paths
through a single 'goto out' label and close the socket there only
if not already closed. Reset 'closed' at the 'again:' label so each
iteration starts with a fresh tracking state. This ensures exactly one
close per iteration in all cases.

Signed-off-by: Geliang Tang <[email protected]>
---
 .../selftests/net/mptcp/mptcp_connect.c       | 24 +++++++++++++------
 1 file changed, 17 insertions(+), 7 deletions(-)

diff --git a/tools/testing/selftests/net/mptcp/mptcp_connect.c b/tools/testing/selftests/net/mptcp/mptcp_connect.c
index f6ebdc5bf745..b04c99605518 100644
--- a/tools/testing/selftests/net/mptcp/mptcp_connect.c
+++ b/tools/testing/selftests/net/mptcp/mptcp_connect.c
@@ -1323,12 +1323,15 @@ static void check_getpeername_connect(int fd)
 			cfg_host, a, cfg_port, b);
 }
 
-static void maybe_close(int fd)
+static bool maybe_close(int fd)
 {
 	unsigned int r = rand();
 
-	if (!(cfg_join || cfg_remove || cfg_repeat > 1) && (r & 1))
+	if (!(cfg_join || cfg_remove || cfg_repeat > 1) && (r & 1)) {
 		close(fd);
+		return true;
+	}
+	return false;
 }
 
 int main_loop_s(int listensock)
@@ -1338,27 +1341,30 @@ int main_loop_s(int listensock)
 	struct pollfd polls;
 	socklen_t salen;
 	int remotesock;
+	bool closed;
 	int err = 0;
 	int fd = 0;
 
 again:
+	closed = false;
 	polls.fd = listensock;
 	polls.events = POLLIN;
 
 	switch (poll(&polls, 1, poll_timeout)) {
 	case -1:
 		perror("poll");
-		return 1;
+		err = 1;
+		goto out;
 	case 0:
 		fprintf(stderr, "%s: timed out\n", __func__);
-		close(listensock);
-		return 2;
+		err = 2;
+		goto out;
 	}
 
 	salen = sizeof(ss);
 	remotesock = accept(listensock, (struct sockaddr *)&ss, &salen);
 	if (remotesock >= 0) {
-		maybe_close(listensock);
+		closed = maybe_close(listensock);
 		check_sockaddr(pf, &ss, salen);
 		check_getpeername(remotesock, &ss, salen);
 
@@ -1374,7 +1380,8 @@ int main_loop_s(int listensock)
 		err = copyfd_io(fd, remotesock, 1, true, &winfo);
 	} else {
 		perror("accept");
-		return 1;
+		err = 1;
+		goto out;
 	}
 
 	if (cfg_input)
@@ -1383,6 +1390,9 @@ int main_loop_s(int listensock)
 	if (!err && --cfg_repeat > 0)
 		goto again;
 
+out:
+	if (!closed)
+		close(listensock);
 	return err;
 }
 
-- 
2.53.0