From 18e47795e598973195887893e7d77baddec53ebb Mon Sep 17 00:00:00 2001
From: "Jason A. Donenfeld" <Jason@zx2c4.com>
Date: Mon, 25 Jan 2021 19:00:43 +0100
Subject: [PATCH] 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 | 66 +++++++++++++++++++++++++++-----------------------
 1 file changed, 36 insertions(+), 30 deletions(-)

diff --git a/device/uapi.go b/device/uapi.go
index c1ddb38..31fbdc7 100644
--- a/device/uapi.go
+++ b/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 {
@@ -391,34 +388,43 @@ 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
+		}
 
-	op, err := buffered.ReadString('\n')
-	if err != nil {
-		return
-	}
+		// handle operation
+		switch op {
+		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)
+			return
+		}
 
-	// handle operation
-	switch op {
-	case "set=1\n":
-		err = device.IpcSetOperation(buffered.Reader)
-	case "get=1\n":
-		err = device.IpcGetOperation(buffered.Writer)
-	default:
-		device.log.Error.Println("invalid UAPI operation:", op)
-		return
-	}
-
-	// write status
-	var status *IPCError
-	if err != nil && !errors.As(err, &status) {
-		// shouldn't happen
-		status = ipcErrorf(ipc.IpcErrorUnknown, "other UAPI error: %w", err)
-	}
-	if status != nil {
-		device.log.Error.Println(status)
-		fmt.Fprintf(buffered, "errno=%d\n\n", status.ErrorCode())
-	} else {
-		fmt.Fprintf(buffered, "errno=0\n\n")
+		// write status
+		var status *IPCError
+		if err != nil && !errors.As(err, &status) {
+			// shouldn't happen
+			status = ipcErrorf(ipc.IpcErrorUnknown, "other UAPI error: %w", err)
+		}
+		if status != nil {
+			device.log.Error.Println(status)
+			fmt.Fprintf(buffered, "errno=%d\n\n", status.ErrorCode())
+		} else {
+			fmt.Fprintf(buffered, "errno=0\n\n")
+		}
+		buffered.Flush()
 	}
 }