Merge branch 'vsock-tests'

Stefano Garzarella says:

====================
vsock/test: add recv_buf()/send_buf() utility functions and some improvements

We recently found that some tests were failing [1].

The problem was that we were not waiting for all the bytes correctly,
so we had a partial read. I had initially suggested using MSG_WAITALL,
but this could have timeout problems.

Since we already had send_byte() and recv_byte() that handled the timeout,
but also the expected return value, I moved that code to two new functions
that we can now use to send/receive generic buffers.

The last commit is just an improvement to a test I found difficult to
understand while using the new functions.

@Arseniy a review and some testing are really appreciated :-)

[1] https://lore.kernel.org/netdev/63xflnwiohdfo6m3vnrrxgv2ulplencpwug5qqacugqh7xxpu3@tsczkuqgwurb/
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

tools/testing/vsock/util.c

@@ -211,102 +211,138 @@ int vsock_seqpacket_accept(unsigned int cid, unsigned int port,
 	return vsock_accept(cid, port, clientaddrp, SOCK_SEQPACKET);
 }
 
-/* Transmit one byte and check the return value.
+/* Transmit bytes from a buffer and check the return value.
  *
  * expected_ret:
  *  <0 Negative errno (for testing errors)
  *   0 End-of-file
- *   1 Success
+ *  >0 Success (bytes successfully written)
  */
-void send_byte(int fd, int expected_ret, int flags)
+void send_buf(int fd, const void *buf, size_t len, int flags,
+	      ssize_t expected_ret)
 {
-	const uint8_t byte = 'A';
-	ssize_t nwritten;
+	ssize_t nwritten = 0;
+	ssize_t ret;
 
 	timeout_begin(TIMEOUT);
 	do {
-		nwritten = send(fd, &byte, sizeof(byte), flags);
-		timeout_check("write");
-	} while (nwritten < 0 && errno == EINTR);
+		ret = send(fd, buf + nwritten, len - nwritten, flags);
+		timeout_check("send");
+
+		if (ret == 0 || (ret < 0 && errno != EINTR))
+			break;
+
+		nwritten += ret;
+	} while (nwritten < len);
 	timeout_end();
 
 	if (expected_ret < 0) {
-		if (nwritten != -1) {
-			fprintf(stderr, "bogus send(2) return value %zd\n",
-				nwritten);
+		if (ret != -1) {
+			fprintf(stderr, "bogus send(2) return value %zd (expected %zd)\n",
+				ret, expected_ret);
 			exit(EXIT_FAILURE);
 		}
 		if (errno != -expected_ret) {
-			perror("write");
+			perror("send");
 			exit(EXIT_FAILURE);
 		}
 		return;
 	}
 
-	if (nwritten < 0) {
-		perror("write");
+	if (ret < 0) {
+		perror("send");
 		exit(EXIT_FAILURE);
 	}
-	if (nwritten == 0) {
-		if (expected_ret == 0)
-			return;
 
-		fprintf(stderr, "unexpected EOF while sending byte\n");
-		exit(EXIT_FAILURE);
-	}
-	if (nwritten != sizeof(byte)) {
-		fprintf(stderr, "bogus send(2) return value %zd\n", nwritten);
+	if (nwritten != expected_ret) {
+		if (ret == 0)
+			fprintf(stderr, "unexpected EOF while sending bytes\n");
+
+		fprintf(stderr, "bogus send(2) bytes written %zd (expected %zd)\n",
+			nwritten, expected_ret);
 		exit(EXIT_FAILURE);
 	}
 }
 
-/* Receive one byte and check the return value.
+/* Receive bytes in a buffer and check the return value.
  *
  * expected_ret:
  *  <0 Negative errno (for testing errors)
  *   0 End-of-file
- *   1 Success
+ *  >0 Success (bytes successfully read)
  */
-void recv_byte(int fd, int expected_ret, int flags)
+void recv_buf(int fd, void *buf, size_t len, int flags, ssize_t expected_ret)
 {
-	uint8_t byte;
-	ssize_t nread;
+	ssize_t nread = 0;
+	ssize_t ret;
 
 	timeout_begin(TIMEOUT);
 	do {
-		nread = recv(fd, &byte, sizeof(byte), flags);
-		timeout_check("read");
-	} while (nread < 0 && errno == EINTR);
+		ret = recv(fd, buf + nread, len - nread, flags);
+		timeout_check("recv");
+
+		if (ret == 0 || (ret < 0 && errno != EINTR))
+			break;
+
+		nread += ret;
+	} while (nread < len);
 	timeout_end();
 
 	if (expected_ret < 0) {
-		if (nread != -1) {
-			fprintf(stderr, "bogus recv(2) return value %zd\n",
-				nread);
+		if (ret != -1) {
+			fprintf(stderr, "bogus recv(2) return value %zd (expected %zd)\n",
+				ret, expected_ret);
 			exit(EXIT_FAILURE);
 		}
 		if (errno != -expected_ret) {
-			perror("read");
+			perror("recv");
 			exit(EXIT_FAILURE);
 		}
 		return;
 	}
 
-	if (nread < 0) {
-		perror("read");
+	if (ret < 0) {
+		perror("recv");
 		exit(EXIT_FAILURE);
 	}
-	if (nread == 0) {
-		if (expected_ret == 0)
-			return;
 
-		fprintf(stderr, "unexpected EOF while receiving byte\n");
-		exit(EXIT_FAILURE);
-	}
-	if (nread != sizeof(byte)) {
-		fprintf(stderr, "bogus recv(2) return value %zd\n", nread);
+	if (nread != expected_ret) {
+		if (ret == 0)
+			fprintf(stderr, "unexpected EOF while receiving bytes\n");
+
+		fprintf(stderr, "bogus recv(2) bytes read %zd (expected %zd)\n",
+			nread, expected_ret);
 		exit(EXIT_FAILURE);
 	}
+}
+
+/* Transmit one byte and check the return value.
+ *
+ * expected_ret:
+ *  <0 Negative errno (for testing errors)
+ *   0 End-of-file
+ *   1 Success
+ */
+void send_byte(int fd, int expected_ret, int flags)
+{
+	const uint8_t byte = 'A';
+
+	send_buf(fd, &byte, sizeof(byte), flags, expected_ret);
+}
+
+/* Receive one byte and check the return value.
+ *
+ * expected_ret:
+ *  <0 Negative errno (for testing errors)
+ *   0 End-of-file
+ *   1 Success
+ */
+void recv_byte(int fd, int expected_ret, int flags)
+{
+	uint8_t byte;
+
+	recv_buf(fd, &byte, sizeof(byte), flags, expected_ret);
+
 	if (byte != 'A') {
 		fprintf(stderr, "unexpected byte read %c\n", byte);
 		exit(EXIT_FAILURE);

tools/testing/vsock/util.h

@@ -42,6 +42,9 @@ int vsock_stream_accept(unsigned int cid, unsigned int port,
 int vsock_seqpacket_accept(unsigned int cid, unsigned int port,
 			   struct sockaddr_vm *clientaddrp);
 void vsock_wait_remote_close(int fd);
+void send_buf(int fd, const void *buf, size_t len, int flags,
+	      ssize_t expected_ret);
+void recv_buf(int fd, void *buf, size_t len, int flags, ssize_t expected_ret);
 void send_byte(int fd, int expected_ret, int flags);
 void recv_byte(int fd, int expected_ret, int flags);
 void run_tests(const struct test_case *test_cases,