vsock/test: add send_buf() utility function

Move the code of send_byte() out in a new utility function that
can be used to send a generic buffer.

This new function can be used when we need to send a custom
buffer and not just a single 'A' byte.
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Reviewed-by: Arseniy Krasnov <avkrasnov@salutedevices.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

tools/testing/vsock/util.c

@@ -211,6 +211,59 @@ int vsock_seqpacket_accept(unsigned int cid, unsigned int port,
 	return vsock_accept(cid, port, clientaddrp, SOCK_SEQPACKET);
 }
 
+/* Transmit bytes from a buffer and check the return value.
+ *
+ * expected_ret:
+ *  <0 Negative errno (for testing errors)
+ *   0 End-of-file
+ *  >0 Success (bytes successfully written)
+ */
+void send_buf(int fd, const void *buf, size_t len, int flags,
+	      ssize_t expected_ret)
+{
+	ssize_t nwritten = 0;
+	ssize_t ret;
+
+	timeout_begin(TIMEOUT);
+	do {
+		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 (ret != -1) {
+			fprintf(stderr, "bogus send(2) return value %zd (expected %zd)\n",
+				ret, expected_ret);
+			exit(EXIT_FAILURE);
+		}
+		if (errno != -expected_ret) {
+			perror("send");
+			exit(EXIT_FAILURE);
+		}
+		return;
+	}
+
+	if (ret < 0) {
+		perror("send");
+		exit(EXIT_FAILURE);
+	}
+
+	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 bytes in a buffer and check the return value.
  *
  * expected_ret:
@@ -273,43 +326,8 @@ 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)
 {
 	const uint8_t byte = 'A';
-	ssize_t nwritten;
-
-	timeout_begin(TIMEOUT);
-	do {
-		nwritten = send(fd, &byte, sizeof(byte), flags);
-		timeout_check("write");
-	} while (nwritten < 0 && errno == EINTR);
-	timeout_end();
-
-	if (expected_ret < 0) {
-		if (nwritten != -1) {
-			fprintf(stderr, "bogus send(2) return value %zd\n",
-				nwritten);
-			exit(EXIT_FAILURE);
-		}
-		if (errno != -expected_ret) {
-			perror("write");
-			exit(EXIT_FAILURE);
-		}
-		return;
-	}
 
-	if (nwritten < 0) {
-		perror("write");
-		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);
-		exit(EXIT_FAILURE);
-	}
+	send_buf(fd, &byte, sizeof(byte), flags, expected_ret);
 }
 
 /* Receive one byte and check the return value.

tools/testing/vsock/util.h

@@ -42,6 +42,8 @@ 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);