vsock/test: rework MSG_PEEK test for SOCK_STREAM

This new version makes test more complicated by adding empty read,
partial read and data comparisons between MSG_PEEK and normal reads.
Signed-off-by: Arseniy Krasnov <AVKrasnov@sberdevices.ru>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

tools/testing/vsock/vsock_test.c

@@ -255,9 +255,14 @@ static void test_stream_multiconn_server(const struct test_opts *opts)
 		close(fds[i]);
 }
 
+#define MSG_PEEK_BUF_LEN 64
+
 static void test_stream_msg_peek_client(const struct test_opts *opts)
 {
+	unsigned char buf[MSG_PEEK_BUF_LEN];
+	ssize_t send_size;
 	int fd;
+	int i;
 
 	fd = vsock_stream_connect(opts->peer_cid, 1234);
 	if (fd < 0) {
@@ -265,12 +270,32 @@ static void test_stream_msg_peek_client(const struct test_opts *opts)
 		exit(EXIT_FAILURE);
 	}
 
-	send_byte(fd, 1, 0);
+	for (i = 0; i < sizeof(buf); i++)
+		buf[i] = rand() & 0xFF;
+
+	control_expectln("SRVREADY");
+
+	send_size = send(fd, buf, sizeof(buf), 0);
+
+	if (send_size < 0) {
+		perror("send");
+		exit(EXIT_FAILURE);
+	}
+
+	if (send_size != sizeof(buf)) {
+		fprintf(stderr, "Invalid send size %zi\n", send_size);
+		exit(EXIT_FAILURE);
+	}
+
 	close(fd);
 }
 
 static void test_stream_msg_peek_server(const struct test_opts *opts)
 {
+	unsigned char buf_half[MSG_PEEK_BUF_LEN / 2];
+	unsigned char buf_normal[MSG_PEEK_BUF_LEN];
+	unsigned char buf_peek[MSG_PEEK_BUF_LEN];
+	ssize_t res;
 	int fd;
 
 	fd = vsock_stream_accept(VMADDR_CID_ANY, 1234, NULL);
@@ -279,8 +304,55 @@ static void test_stream_msg_peek_server(const struct test_opts *opts)
 		exit(EXIT_FAILURE);
 	}
 
-	recv_byte(fd, 1, MSG_PEEK);
-	recv_byte(fd, 1, 0);
+	/* Peek from empty socket. */
+	res = recv(fd, buf_peek, sizeof(buf_peek), MSG_PEEK | MSG_DONTWAIT);
+	if (res != -1) {
+		fprintf(stderr, "expected recv(2) failure, got %zi\n", res);
+		exit(EXIT_FAILURE);
+	}
+
+	if (errno != EAGAIN) {
+		perror("EAGAIN expected");
+		exit(EXIT_FAILURE);
+	}
+
+	control_writeln("SRVREADY");
+
+	/* Peek part of data. */
+	res = recv(fd, buf_half, sizeof(buf_half), MSG_PEEK);
+	if (res != sizeof(buf_half)) {
+		fprintf(stderr, "recv(2) + MSG_PEEK, expected %zu, got %zi\n",
+			sizeof(buf_half), res);
+		exit(EXIT_FAILURE);
+	}
+
+	/* Peek whole data. */
+	res = recv(fd, buf_peek, sizeof(buf_peek), MSG_PEEK);
+	if (res != sizeof(buf_peek)) {
+		fprintf(stderr, "recv(2) + MSG_PEEK, expected %zu, got %zi\n",
+			sizeof(buf_peek), res);
+		exit(EXIT_FAILURE);
+	}
+
+	/* Compare partial and full peek. */
+	if (memcmp(buf_half, buf_peek, sizeof(buf_half))) {
+		fprintf(stderr, "Partial peek data mismatch\n");
+		exit(EXIT_FAILURE);
+	}
+
+	res = recv(fd, buf_normal, sizeof(buf_normal), 0);
+	if (res != sizeof(buf_normal)) {
+		fprintf(stderr, "recv(2), expected %zu, got %zi\n",
+			sizeof(buf_normal), res);
+		exit(EXIT_FAILURE);
+	}
+
+	/* Compare full peek and normal read. */
+	if (memcmp(buf_peek, buf_normal, sizeof(buf_peek))) {
+		fprintf(stderr, "Full peek data mismatch\n");
+		exit(EXIT_FAILURE);
+	}
+
 	close(fd);
 }