Use generic hot key combo for client control

common/rfb/CConnection.cxx

@@ -32,11 +32,16 @@
 #include <rfb/CMsgWriter.h>
 #include <rfb/CSecurity.h>
 #include <rfb/Decoder.h>
+#include <rfb/KeysymStr.h>
 #include <rfb/Security.h>
 #include <rfb/SecurityClient.h>
 #include <rfb/CConnection.h>
 #include <rfb/util.h>
 
+#define XK_MISCELLANY
+#define XK_XKB_KEYS
+#include <rfb/keysymdef.h>
+
 #include <rfb/LogWriter.h>
 
 #include <rdr/InStream.h>
@@ -693,6 +698,89 @@ void CConnection::sendClipboardData(const char* data)
   }
 }
 
+void CConnection::sendKeyPress(int systemKeyCode,
+                               rdr::U32 keyCode, rdr::U32 keySym)
+{
+  // For the first few years, there wasn't a good consensus on what the
+  // Windows keys should be mapped to for X11. So we need to help out a
+  // bit and map all variants to the same key...
+  switch (keySym) {
+  case XK_Hyper_L:
+    keySym = XK_Super_L;
+    break;
+  case XK_Hyper_R:
+    keySym = XK_Super_R;
+    break;
+  // There has been several variants for Shift-Tab over the years.
+  // RFB states that we should always send a normal tab.
+  case XK_ISO_Left_Tab:
+    keySym = XK_Tab;
+    break;
+  }
+
+#ifdef __APPLE__
+  // Alt on OS X behaves more like AltGr on other systems, and to get
+  // sane behaviour we should translate things in that manner for the
+  // remote VNC server. However that means we lose the ability to use
+  // Alt as a shortcut modifier. Do what RealVNC does and hijack the
+  // left command key as an Alt replacement.
+  switch (keySym) {
+  case XK_Super_L:
+    keySym = XK_Alt_L;
+    break;
+  case XK_Super_R:
+    keySym = XK_Super_L;
+    break;
+  case XK_Alt_L:
+    keySym = XK_Mode_switch;
+    break;
+  case XK_Alt_R:
+    keySym = XK_ISO_Level3_Shift;
+    break;
+  }
+#endif
+
+  // Because of the way keyboards work, we cannot expect to have the same
+  // symbol on release as when pressed. This breaks the VNC protocol however,
+  // so we need to keep track of what keysym a key _code_ generated on press
+  // and send the same on release.
+  downKeys[systemKeyCode].keyCode = keyCode;
+  downKeys[systemKeyCode].keySym = keySym;
+
+  vlog.debug("Key pressed: %d => 0x%04x / %s (0x%04x)",
+             systemKeyCode, keyCode, KeySymName(keySym), keySym);
+
+  writer()->writeKeyEvent(keySym, keyCode, true);
+}
+
+void CConnection::sendKeyRelease(int systemKeyCode)
+{
+  DownMap::iterator iter;
+
+  iter = downKeys.find(systemKeyCode);
+  if (iter == downKeys.end()) {
+    // These occur somewhat frequently so let's not spam them unless
+    // logging is turned up.
+    vlog.debug("Unexpected release of key code %d", systemKeyCode);
+    return;
+  }
+
+  vlog.debug("Key released: %d => 0x%04x / %s (0x%04x)",
+             systemKeyCode, iter->second.keyCode,
+             KeySymName(iter->second.keySym), iter->second.keySym);
+
+  writer()->writeKeyEvent(iter->second.keySym,
+                          iter->second.keyCode, false);
+
+  downKeys.erase(iter);
+}
+
+void CConnection::releaseAllKeys()
+{
+  while (!downKeys.empty())
+    sendKeyRelease(downKeys.begin()->first);
+}
+
 void CConnection::refreshFramebuffer()
 {
   forceNonincremental = true;

common/rfb/CConnection.h

@@ -24,6 +24,8 @@
 #ifndef __RFB_CCONNECTION_H__
 #define __RFB_CCONNECTION_H__
 
+#include <map>
+
 #include <rfb/CMsgHandler.h>
 #include <rfb/DecodeManager.h>
 #include <rfb/SecurityClient.h>
@@ -180,6 +182,18 @@ namespace rfb {
     // clipboard via handleClipboardRequest().
     virtual void sendClipboardData(const char* data);
 
+    // sendKeyPress()/sendKeyRelease() send keyboard events to the
+    // server
+    void sendKeyPress(int systemKeyCode, rdr::U32 keyCode, rdr::U32 keySym);
+    void sendKeyRelease(int systemKeyCode);
+
+    // releaseAllKeys() sends keyboard release events to the server for
+    // all keys that are currently pressed down by this client,
+    // avoiding keys getting stuck. This can be useful if the client
+    // loses keyboard focus or otherwise no longer gets keyboard events
+    // from the system.
+    void releaseAllKeys();
+
     // refreshFramebuffer() forces a complete refresh of the entire
     // framebuffer
     void refreshFramebuffer();
@@ -296,6 +310,13 @@ namespace rfb {
     char* serverClipboard;
     bool hasLocalClipboard;
     bool unsolicitedClipboardAttempt;
+
+    struct DownKey {
+        rdr::U32 keyCode;
+        rdr::U32 keySym;
+    };
+    typedef std::map<int, DownKey> DownMap;
+    DownMap downKeys;
   };
 }
 #endif

common/rfb/CMakeLists.txt

@@ -28,6 +28,7 @@ add_library(rfb STATIC
   JpegCompressor.cxx
   JpegDecompressor.cxx
   KeyRemapper.cxx
+  KeysymStr.c
   LogWriter.cxx
   Logger.cxx
   Logger_file.cxx

common/rfb/ClientParams.cxx

@@ -23,13 +23,16 @@
 #endif
 
 #include <rfb/Exception.h>
+#include <rfb/LogWriter.h>
 #include <rfb/encodings.h>
 #include <rfb/ledStates.h>
 #include <rfb/clipboardTypes.h>
 #include <rfb/ClientParams.h>
 
 using namespace rfb;
 
+static LogWriter vlog("ClientParams");
+
 ClientParams::ClientParams()
   : majorVersion(0), minorVersion(0),
     compressLevel(2), qualityLevel(-1), fineQualityLevel(-1),
@@ -62,8 +65,14 @@ void ClientParams::setDimensions(int width, int height)
 
 void ClientParams::setDimensions(int width, int height, const ScreenSet& layout)
 {
-  if (!layout.validate(width, height))
+  if (!layout.validate(width, height)) {
+    char buffer[2048];
+    vlog.debug("Invalid screen layout for %dx%d:", width, height);
+    layout.print(buffer, sizeof(buffer));
+    vlog.debug("%s", buffer);
+
     throw Exception("Attempted to configure an invalid screen layout");
+  }
 
   width_ = width;
   height_ = height;

common/rfb/KeysymStr.c

@@ -0,0 +1,108 @@
+
+/*
+
+Copyright 1990, 1998  The Open Group
+
+Permission to use, copy, modify, distribute, and sell this software and its
+documentation for any purpose is hereby granted without fee, provided that
+the above copyright notice appear in all copies and that both that
+copyright notice and this permission notice appear in supporting
+documentation.
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
+OPEN GROUP BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+Except as contained in this notice, the name of The Open Group shall not be
+used in advertising or otherwise to promote the sale, use or other dealings
+in this Software without prior written authorization from The Open Group.
+
+*/
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <stdlib.h>
+
+#include "keysymdef.h"
+#include "KeysymStr.h"
+
+#define NEEDKTABLE
+#define NEEDVTABLE
+#include "ks_tables.h"
+
+static const char *_XKeysymToString(unsigned ks)
+{
+    if (!ks || (ks & ((unsigned long) ~0x1fffffff)) != 0)
+	return ((char *)NULL);
+    if (ks == XK_VoidSymbol)
+	ks = 0;
+    if (ks <= 0x1fffffff)
+    {
+	unsigned char val1 = ks >> 24;
+	unsigned char val2 = (ks >> 16) & 0xff;
+	unsigned char val3 = (ks >> 8) & 0xff;
+	unsigned char val4 = ks & 0xff;
+	int i = ks % VTABLESIZE;
+	int h = i + 1;
+	int n = VMAXHASH;
+	int idx;
+	while ((idx = hashKeysym[i]))
+	{
+	    const unsigned char *entry = &_XkeyTable[idx];
+	    if ((entry[0] == val1) && (entry[1] == val2) &&
+                (entry[2] == val3) && (entry[3] == val4))
+		return ((char *)entry + 4);
+	    if (!--n)
+		break;
+	    i += h;
+	    if (i >= VTABLESIZE)
+		i -= VTABLESIZE;
+	}
+    }
+
+    if (ks >= 0x01000100 && ks <= 0x0110ffff) {
+        unsigned val = ks & 0xffffff;
+        char *s;
+        int i;
+        if (val & 0xff0000)
+            i = 10;
+        else
+            i = 6;
+        s = malloc(i);
+        if (s == NULL)
+            return s;
+        i--;
+        s[i--] = '\0';
+        for (; i; i--){
+            unsigned char val1 = val & 0xf;
+            val >>= 4;
+            if (val1 < 10)
+                s[i] = '0'+ val1;
+            else
+                s[i] = 'A'+ val1 - 10;
+        }
+        s[i] = 'U';
+        return s;
+    }
+    return ((char *) NULL);
+}
+
+const char* KeySymName(unsigned keysym)
+{
+    const char* name;
+
+    name = _XKeysymToString(keysym);
+    if (name == NULL)
+      return "[unknown keysym]";
+
+    return name;
+}
+

vncviewer/menukey.h → common/rfb/KeysymStr.h

@@ -1,4 +1,4 @@
-/* Copyright 2011 Martin Koegler <[email protected]>
+/* Copyright 2021 Pierre Ossman for Cendio AB
  * 
  * This is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -15,20 +15,18 @@
  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307,
  * USA.
  */
-#ifndef __KEYSYM_H__
-#define __KEYSYM_H__
 
-#include <rdr/types.h>
+#ifndef __RFB_KEYSYMSTR_H__
+#define __RFB_KEYSYMSTR_H__
 
-typedef struct {
-  const char* name;
-  int fltkcode;
-  int keycode;
-  rdr::U32 keysym;
-} MenuKeySymbol;
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+const char* KeySymName(unsigned keysym);
 
-void getMenuKey(int *fltkcode, int *keycode, rdr::U32 *keysym);
-int getMenuKeySymbolCount();
-const MenuKeySymbol* getMenuKeySymbols();
+#ifdef __cplusplus
+}
+#endif
 
 #endif

common/rfb/ServerParams.cxx

@@ -23,11 +23,14 @@
 #endif
 
 #include <rfb/Exception.h>
+#include <rfb/LogWriter.h>
 #include <rfb/ledStates.h>
 #include <rfb/ServerParams.h>
 
 using namespace rfb;
 
+static LogWriter vlog("ServerParams");
+
 ServerParams::ServerParams()
   : majorVersion(0), minorVersion(0),
     supportsQEMUKeyEvent(false),
@@ -59,8 +62,14 @@ void ServerParams::setDimensions(int width, int height)
 
 void ServerParams::setDimensions(int width, int height, const ScreenSet& layout)
 {
-  if (!layout.validate(width, height))
+  if (!layout.validate(width, height)) {
+    char buffer[2048];
+    vlog.debug("Invalid screen layout for %dx%d:", width, height);
+    layout.print(buffer, sizeof(buffer));
+    vlog.debug("%s", buffer);
+
     throw Exception("Attempted to configure an invalid screen layout");
+  }
 
   width_ = width;
   height_ = height;

common/rfb/VNCSConnectionST.cxx

@@ -27,6 +27,7 @@
 #include <rfb/ComparingUpdateTracker.h>
 #include <rfb/Encoder.h>
 #include <rfb/KeyRemapper.h>
+#include <rfb/KeysymStr.h>
 #include <rfb/LogWriter.h>
 #include <rfb/Security.h>
 #include <rfb/ServerCore.h>
@@ -86,8 +87,8 @@ VNCSConnectionST::~VNCSConnectionST()
     keycode = pressedKeys.begin()->first;
     pressedKeys.erase(pressedKeys.begin());
 
-    vlog.debug("Releasing key 0x%x / 0x%x on client disconnect",
-               keysym, keycode);
+    vlog.debug("Releasing key 0x%04x / %s (0x%04x) on client disconnect",
+               keycode, KeySymName(keysym), keysym);
     server->keyEvent(keysym, keycode, false);
   }
 
@@ -511,9 +512,11 @@ void VNCSConnectionST::keyEvent(rdr::U32 keysym, rdr::U32 keycode, bool down) {
   if (!rfb::Server::acceptKeyEvents) return;
 
   if (down)
-    vlog.debug("Key pressed: 0x%x / 0x%x", keysym, keycode);
+    vlog.debug("Key pressed: 0x%04x / %s (0x%04x)",
+               keycode, KeySymName(keysym), keysym);
   else
-    vlog.debug("Key released: 0x%x / 0x%x", keysym, keycode);
+    vlog.debug("Key released: 0x%04x / %s (0x%04x)",
+               keycode, KeySymName(keysym), keysym);
 
   // Avoid lock keys if we don't know the server state
   if ((server->getLEDState() == ledUnknown) &&