lib: xpc: implement scatter/gather i/o for buffers and messages

lib/libxpc/msg.c

@@ -89,17 +89,17 @@ kern_status_t xpc_msg_read(
 	const xpc_msg_t *msg,
 	size_t offset,
 	void *p,
-	size_t count)
+	size_t count,
+	size_t *nr_read)
 {
 	kern_iovec_t iov = IOVEC(p, count);
-	size_t r = 0;
 	return msg_read(
 		msg->msg_sender.e_channel,
 		msg->msg_sender.e_msg,
 		offset,
 		&iov,
 		1,
-		&r);
+		nr_read);
 }
 
 kern_status_t xpc_msg_write(
@@ -119,6 +119,38 @@ kern_status_t xpc_msg_write(
 		nr_written);
 }
 
+kern_status_t xpc_msg_readv(
+	const xpc_msg_t *msg,
+	size_t offset,
+	kern_iovec_t *iov,
+	size_t nr_iov,
+	size_t *nr_read)
+{
+	return msg_read(
+		msg->msg_sender.e_channel,
+		msg->msg_sender.e_msg,
+		offset,
+		iov,
+		nr_iov,
+		nr_read);
+}
+
+kern_status_t xpc_msg_writev(
+	const xpc_msg_t *msg,
+	size_t offset,
+	kern_iovec_t *iov,
+	size_t nr_iov,
+	size_t *nr_written)
+{
+	return msg_write(
+		msg->msg_sender.e_channel,
+		msg->msg_sender.e_msg,
+		offset,
+		iov,
+		nr_iov,
+		nr_written);
+}
+
 kern_status_t xpc_msg_reply(
 	const xpc_msg_t *msg,
 	kern_iovec_t *iov,