test/socket-nb: add MSG_DONTWAIT test case

We expect -EAGAIN to be returned in the CQE if an attempt is done at
reading an empty socket, IFF MSG_DONTWAIT is set. O_NONBLOCK should
not impact that at all.

Signed-off-by: Jens Axboe <[email protected]>

test/Makefile

@@ -203,6 +203,7 @@ test_srcs := \
 	socket.c \
 	socket-io-cmd.c \
 	socket-getsetsock-cmd.c \
+	socket-nb.c \
 	socket-rw.c \
 	socket-rw-eagain.c \
 	socket-rw-offset.c \

test/socket-nb.c

@@ -0,0 +1,158 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * Check that recv on an empty socket will bubble back -EAGAIN if
+ * MSG_DONTWAIT is set, regardless of whether or not O_NONBLOCK is set
+ * on the socket itself.
+ */
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <assert.h>
+
+#include <errno.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+#include <netinet/tcp.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+
+#include "liburing.h"
+#include "helpers.h"
+
+static int test(int o_nonblock, int msg_dontwait)
+{
+	int p_fd[2], ret, flags, recv_s0, val;
+	struct io_uring_sqe *sqe;
+	struct io_uring_cqe *cqe;
+	struct sockaddr_in addr;
+	struct io_uring ring;
+	char recv_buff[128];
+
+	recv_s0 = socket(AF_INET, SOCK_STREAM | SOCK_CLOEXEC, IPPROTO_TCP);
+
+	val = 1;
+	ret = setsockopt(recv_s0, SOL_SOCKET, SO_REUSEPORT, &val, sizeof(val));
+	assert(ret != -1);
+	ret = setsockopt(recv_s0, SOL_SOCKET, SO_REUSEADDR, &val, sizeof(val));
+	assert(ret != -1);
+
+	addr.sin_family = AF_INET;
+	addr.sin_addr.s_addr = inet_addr("127.0.0.1");
+	ret = t_bind_ephemeral_port(recv_s0, &addr);
+	assert(!ret);
+	ret = listen(recv_s0, 128);
+	assert(ret != -1);
+
+	p_fd[1] = socket(AF_INET, SOCK_STREAM | SOCK_CLOEXEC, IPPROTO_TCP);
+
+	val = 1;
+	ret = setsockopt(p_fd[1], IPPROTO_TCP, TCP_NODELAY, &val, sizeof(val));
+	assert(ret != -1);
+
+	flags = fcntl(p_fd[1], F_GETFL, 0);
+	assert(flags != -1);
+
+	flags |= O_NONBLOCK;
+	ret = fcntl(p_fd[1], F_SETFL, flags);
+	assert(ret != -1);
+
+	ret = connect(p_fd[1], (struct sockaddr *) &addr, sizeof(addr));
+	assert(ret == -1);
+
+	p_fd[0] = accept(recv_s0, NULL, NULL);
+	assert(p_fd[0] != -1);
+
+	if (o_nonblock) {
+		flags = fcntl(p_fd[0], F_GETFL, 0);
+		assert(flags != -1);
+
+		flags |= O_NONBLOCK;
+		ret = fcntl(p_fd[0], F_SETFL, flags);
+		assert(ret != -1);
+	}
+
+	while (1) {
+		int32_t code;
+		socklen_t code_len = sizeof(code);
+
+		ret = getsockopt(p_fd[1], SOL_SOCKET, SO_ERROR, &code, &code_len);
+		assert(ret != -1);
+
+		if (!code)
+			break;
+	}
+
+	ret = io_uring_queue_init(32, &ring, 0);
+	assert(ret >= 0);
+
+	flags = msg_dontwait ? MSG_DONTWAIT : 0;
+	sqe = io_uring_get_sqe(&ring);
+	io_uring_prep_recv(sqe, p_fd[0], recv_buff, sizeof(recv_buff), flags);
+	sqe->user_data = 1;
+	io_uring_submit(&ring);
+
+	ret = io_uring_peek_cqe(&ring, &cqe);
+	if (ret) {
+		if (ret != -EAGAIN) {
+			fprintf(stderr, "bad peek: %d\n", ret);
+			goto err;
+		}
+		if (msg_dontwait) {
+			fprintf(stderr, "Got -EAGAIN without MSG_DONTWAIT\n");
+			goto err;
+		}
+	} else {
+		if (!msg_dontwait) {
+			fprintf(stderr, "Unexpected completion\n");
+			goto err;
+		}
+	}
+
+	io_uring_queue_exit(&ring);
+	close(p_fd[0]);
+	close(p_fd[1]);
+	close(recv_s0);
+	return T_EXIT_PASS;
+err:
+	io_uring_queue_exit(&ring);
+	close(p_fd[0]);
+	close(p_fd[1]);
+	close(recv_s0);
+	return T_EXIT_FAIL;
+}
+
+int main(int argc, char *argv[])
+{
+	int ret;
+
+	if (argc > 1)
+		return T_EXIT_SKIP;
+
+	ret = test(0, 0);
+	if (ret) {
+		fprintf(stderr, "test 0 0 failed\n");
+		return T_EXIT_FAIL;
+	}
+
+	ret = test(0, 1);
+	if (ret) {
+		fprintf(stderr, "test 0 1 failed\n");
+		return T_EXIT_FAIL;
+	}
+
+	ret = test(1, 0);
+	if (ret) {
+		fprintf(stderr, "test 1 0 failed\n");
+		return T_EXIT_FAIL;
+	}
+
+	ret = test(1, 1);
+	if (ret) {
+		fprintf(stderr, "test 1 1 failed\n");
+		return T_EXIT_FAIL;
+	}
+
+	return T_EXIT_PASS;
+}