Fix handling of meta keys in client

Author: IDisposable

jsonrpc.go

@@ -13,6 +13,7 @@ import (
 	"time"
 
 	"github.com/pion/webrtc/v4"
+	"github.com/rs/zerolog"
 	"go.bug.st/serial"
 
 	"github.com/jetkvm/kvm/internal/usbgadget"
@@ -134,7 +135,7 @@ func onRPCMessage(message webrtc.DataChannelMessage, session *Session) {
 	}
 
 	scopedLogger.Trace().Msg("Calling RPC handler")
-	result, err := callRPCHandler(handler, request.Params)
+	result, err := callRPCHandler(scopedLogger, handler, request.Params)
 	if err != nil {
 		scopedLogger.Error().Err(err).Msg("Error calling RPC handler")
 		errorResponse := JSONRPCResponse{
@@ -472,7 +473,7 @@ type RPCHandler struct {
 }
 
 // call the handler but recover from a panic to ensure our RPC thread doesn't collapse on malformed calls
-func callRPCHandler(handler RPCHandler, params map[string]interface{}) (result interface{}, err error) {
+func callRPCHandler(logger zerolog.Logger, handler RPCHandler, params map[string]interface{}) (result interface{}, err error) {
 	// Use defer to recover from a panic
 	defer func() {
 		if r := recover(); r != nil {
@@ -486,11 +487,11 @@ func callRPCHandler(handler RPCHandler, params map[string]interface{}) (result i
 	}()
 
 	// Call the handler
-	result, err = riskyCallRPCHandler(handler, params)
-	return result, err
+	result, err = riskyCallRPCHandler(logger, handler, params)
+	return result, err // do not combine these two lines into one, as it breaks the above defer function's setting of err
 }
 
-func riskyCallRPCHandler(handler RPCHandler, params map[string]interface{}) (interface{}, error) {
+func riskyCallRPCHandler(logger zerolog.Logger, handler RPCHandler, params map[string]interface{}) (interface{}, error) {
 	handlerValue := reflect.ValueOf(handler.Func)
 	handlerType := handlerValue.Type()
 
@@ -499,20 +500,24 @@ func riskyCallRPCHandler(handler RPCHandler, params map[string]interface{}) (int
 	}
 
 	numParams := handlerType.NumIn()
-	args := make([]reflect.Value, numParams)
-	// Get the parameter names from the RPCHandler
-	paramNames := handler.Params
+	paramNames := handler.Params // Get the parameter names from the RPCHandler
 
 	if len(paramNames) != numParams {
-		return nil, errors.New("mismatch between handler parameters and defined parameter names")
+		err := fmt.Errorf("mismatch between handler parameters (%d) and defined parameter names (%d)", numParams, len(paramNames))
+		logger.Error().Strs("paramNames", paramNames).Err(err).Msg("Cannot call RPC handler")
+		return nil, err
 	}
 
+	args := make([]reflect.Value, numParams)
+
 	for i := 0; i < numParams; i++ {
 		paramType := handlerType.In(i)
 		paramName := paramNames[i]
 		paramValue, ok := params[paramName]
 		if !ok {
-			return nil, errors.New("missing parameter: " + paramName)
+			err := fmt.Errorf("missing parameter: %s", paramName)
+			logger.Error().Err(err).Msg("Cannot marshal arguments for RPC handler")
+			return nil, err
 		}
 
 		convertedValue := reflect.ValueOf(paramValue)
@@ -529,7 +534,7 @@ func riskyCallRPCHandler(handler RPCHandler, params map[string]interface{}) (int
 						if elemValue.Kind() == reflect.Float64 && paramType.Elem().Kind() == reflect.Uint8 {
 							intValue := int(elemValue.Float())
 							if intValue < 0 || intValue > 255 {
-								return nil, fmt.Errorf("value out of range for uint8: %v", intValue)
+								return nil, fmt.Errorf("value out of range for uint8: %v for parameter %s", intValue, paramName)
 							}
 							newSlice.Index(j).SetUint(uint64(intValue))
 						} else {
@@ -545,12 +550,12 @@ func riskyCallRPCHandler(handler RPCHandler, params map[string]interface{}) (int
 			} else if paramType.Kind() == reflect.Struct && convertedValue.Kind() == reflect.Map {
 				jsonData, err := json.Marshal(convertedValue.Interface())
 				if err != nil {
-					return nil, fmt.Errorf("failed to marshal map to JSON: %v", err)
+					return nil, fmt.Errorf("failed to marshal map to JSON: %v for parameter %s", err, paramName)
 				}
 
 				newStruct := reflect.New(paramType).Interface()
 				if err := json.Unmarshal(jsonData, newStruct); err != nil {
-					return nil, fmt.Errorf("failed to unmarshal JSON into struct: %v", err)
+					return nil, fmt.Errorf("failed to unmarshal JSON into struct: %v for parameter %s", err, paramName)
 				}
 				args[i] = reflect.ValueOf(newStruct).Elem()
 			} else {
@@ -561,30 +566,40 @@ func riskyCallRPCHandler(handler RPCHandler, params map[string]interface{}) (int
 		}
 	}
 
+	logger.Trace().Interface("args", args).Msg("Calling RPC handler")
 	results := handlerValue.Call(args)
 
 	if len(results) == 0 {
 		return nil, nil
 	}
 
 	if len(results) == 1 {
-		if results[0].Type().Implements(reflect.TypeOf((*error)(nil)).Elem()) {
-			if !results[0].IsNil() {
-				return nil, results[0].Interface().(error)
-			}
-			return nil, nil
+		if ok, err := asError(results[0]); ok {
+			return nil, err
 		}
 		return results[0].Interface(), nil
 	}
 
-	if len(results) == 2 && results[1].Type().Implements(reflect.TypeOf((*error)(nil)).Elem()) {
-		if !results[1].IsNil() {
-			return nil, results[1].Interface().(error)
+	if len(results) == 2 {
+		if ok, err := asError(results[1]); ok {
+			if err != nil {
+				return nil, err
+			}
 		}
 		return results[0].Interface(), nil
 	}
 
-	return nil, errors.New("unexpected return values from handler")
+	return nil, fmt.Errorf("too many return values from handler: %d", len(results))
+}
+
+func asError(value reflect.Value) (bool, error) {
+	if value.Type().Implements(reflect.TypeOf((*error)(nil)).Elem()) {
+		if value.IsNil() {
+			return true, nil
+		}
+		return true, value.Interface().(error)
+	}
+	return false, nil
 }
 
 func rpcSetMassStorageMode(mode string) (string, error) {

ui/src/components/WebRTCVideo.tsx

@@ -337,17 +337,21 @@ export default function WebRTCVideo() {
       const code = getAdjustedKeyCode(e);
       const hidKey = keys[code];
 
+      if (hidKey === undefined) {
+        console.warn(`Key down not mapped: ${code}`);
+        return;
+      }
+
       // When pressing the meta key + another key, the key will never trigger a keyup
       // event, so we need to clear the keys after a short delay
       // https://bugs.chromium.org/p/chromium/issues/detail?id=28089
       // https://bugzilla.mozilla.org/show_bug.cgi?id=1299553
-      if (e.metaKey) {
+      if (e.metaKey && hidKey < 0xE0) {
         setTimeout(() => {
           sendKeypressEvent(hidKey, false);
         }, 10);
       }
       sendKeypressEvent(hidKey, true);
-      
     },
     [sendKeypressEvent],
   );
@@ -357,6 +361,12 @@ export default function WebRTCVideo() {
       e.preventDefault();
       const code = getAdjustedKeyCode(e);
       const hidKey = keys[code];
+      
+      if (hidKey === undefined) {
+        console.warn(`Key up not mapped: ${code}`);
+        return;
+      }
+
       sendKeypressEvent(hidKey, false);
     },
     [sendKeypressEvent],

ui/src/keyboardMappings.ts

@@ -14,7 +14,7 @@ export const keys = {
   CapsLock: 0x39,
   Comma: 0x36,
   Compose: 0x65,
-  ContextMenu: 0,
+  ContextMenu: 0x65,  // same as Compose
   Delete: 0x4c,
   Digit0: 0x27,
   Digit1: 0x1e,
@@ -121,6 +121,14 @@ export const keys = {
   Space: 0x2c,
   SystemRequest: 0x9a,
   Tab: 0x2b,
+  ControlLeft: 0xe0,
+  ControlRight: 0xe4,
+  ShiftLeft: 0xe1,
+  ShiftRight: 0xe5,
+  AltLeft: 0xe2,
+  AltRight: 0xe6,
+  MetaLeft: 0xe3,
+  MetaRight: 0xe7,
 } as Record<string, number>;
 
 export const modifiers = {