device: allow pipelining UAPI requests

The original spec ends with \n\n especially for this reason.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

device/uapi.go

@@ -380,9 +380,6 @@ func (device *Device) IpcSet(uapiConf string) error {
 }
 
 func (device *Device) IpcHandle(socket net.Conn) {
-
-	// create buffered read/writer
-
 	defer socket.Close()
 
 	buffered := func(s io.ReadWriter) *bufio.ReadWriter {
@@ -391,8 +388,7 @@ func (device *Device) IpcHandle(socket net.Conn) {
 		return bufio.NewReadWriter(reader, writer)
 	}(socket)
 
-	defer buffered.Flush()
-
+	for {
 		op, err := buffered.ReadString('\n')
 		if err != nil {
 			return
@@ -403,6 +399,14 @@ func (device *Device) IpcHandle(socket net.Conn) {
 		case "set=1\n":
 			err = device.IpcSetOperation(buffered.Reader)
 		case "get=1\n":
+			nextByte, err := buffered.ReadByte()
+			if err != nil {
+				return
+			}
+			if nextByte != '\n' {
+				err = ipcErrorf(ipc.IpcErrorInvalid, "trailing character in UAPI get: %c", nextByte, err)
+				break
+			}
 			err = device.IpcGetOperation(buffered.Writer)
 		default:
 			device.log.Error.Println("invalid UAPI operation:", op)
@@ -421,4 +425,6 @@ func (device *Device) IpcHandle(socket net.Conn) {
 		} else {
 			fmt.Fprintf(buffered, "errno=0\n\n")
 		}
+		buffered.Flush()
+	}
 }