[PATCH liburing v1 02/12] t/poll-link: Don't brute force the port number

[Ammar Faizi <ammarfaizi2@gnuweeb.org>]

From: Ammar Faizi <ammarfaizi2@gnuweeb.org>

Don't brute force the port number, use `t_bind_ephemeral_port()`,
much simpler and reliable for choosing a port number that is not
in use.

Cc: Dylan Yudaken <dylany@fb.com>
Cc: Facebook Kernel Team <kernel-team@fb.com>
Cc: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Ammar Faizi <ammarfaizi2@gnuweeb.org>
---
 test/poll-link.c | 20 ++++++--------------
 1 file changed, 6 insertions(+), 14 deletions(-)

diff --git a/test/poll-link.c b/test/poll-link.c
index 197ad77..a6fe0de 100644
--- a/test/poll-link.c
+++ b/test/poll-link.c
@@ -3,26 +3,27 @@
 #include <stdio.h>
 #include <unistd.h>
 #include <stdlib.h>
 #include <string.h>
 #include <fcntl.h>
 #include <assert.h>
 #include <pthread.h>
 #include <sys/socket.h>
 #include <netinet/tcp.h>
 #include <netinet/in.h>
 #include <poll.h>
 #include <arpa/inet.h>
 
+#include "helpers.h"
 #include "liburing.h"
 
 pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;
 pthread_cond_t cond = PTHREAD_COND_INITIALIZER;
 
 static int recv_thread_ready = 0;
 static int recv_thread_done = 0;
 
 static void signal_var(int *var)
 {
         pthread_mutex_lock(&mutex);
         *var = 1;
         pthread_cond_signal(&cond);
@@ -79,47 +80,39 @@ void *recv_thread(void *arg)
 
 	ret = io_uring_queue_init(8, &ring, 0);
 	assert(ret == 0);
 
 	int s0 = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
 	assert(s0 != -1);
 
 	int32_t val = 1;
 	ret = setsockopt(s0, SOL_SOCKET, SO_REUSEPORT, &val, sizeof(val));
 	assert(ret != -1);
 	ret = setsockopt(s0, SOL_SOCKET, SO_REUSEADDR, &val, sizeof(val));
 	assert(ret != -1);
 
-	struct sockaddr_in addr;
+	struct sockaddr_in addr = { };
 
 	addr.sin_family = AF_INET;
 	data->addr = inet_addr("127.0.0.1");
 	addr.sin_addr.s_addr = data->addr;
 
-	i = 0;
-	do {
-		data->port = htons(1025 + (rand() % 64510));
-		addr.sin_port = data->port;
-
-		if (bind(s0, (struct sockaddr*)&addr, sizeof(addr)) != -1)
-			break;
-	} while (++i < 100);
-
-	if (i >= 100) {
-		fprintf(stderr, "Can't find good port, skipped\n");
+	if (t_bind_ephemeral_port(s0, &addr)) {
+		perror("bind");
 		data->stop = 1;
 		signal_var(&recv_thread_ready);
-		goto out;
+		goto err;
 	}
+	data->port = addr.sin_port;
 
 	ret = listen(s0, 128);
 	assert(ret != -1);
 
 	signal_var(&recv_thread_ready);
 
 	sqe = io_uring_get_sqe(&ring);
 	assert(sqe != NULL);
 
 	io_uring_prep_poll_add(sqe, s0, POLLIN | POLLHUP | POLLERR);
 	sqe->flags |= IOSQE_IO_LINK;
 	sqe->user_data = 1;
 
@@ -148,27 +141,26 @@ void *recv_thread(void *arg)
 			fprintf(stderr, "cqe %" PRIu64 " got %x, wanted mask %x\n",
 					(uint64_t) cqe->user_data, cqe->res,
 					data->expected[idx]);
 			goto err;
 		} else if (!data->is_mask[idx] && cqe->res != data->expected[idx]) {
 			fprintf(stderr, "cqe %" PRIu64 " got %d, wanted %d\n",
 					(uint64_t) cqe->user_data, cqe->res,
 					data->expected[idx]);
 			goto err;
 		}
 		io_uring_cqe_seen(&ring, cqe);
 	}
 
-out:
 	signal_var(&recv_thread_done);
 	close(s0);
 	io_uring_queue_exit(&ring);
 	return NULL;
 err:
 	signal_var(&recv_thread_done);
 	close(s0);
 	io_uring_queue_exit(&ring);
 	return (void *) 1;
 }
 
 static int test_poll_timeout(int do_connect, unsigned long timeout)
 {
-- 
Ammar Faizi