nxagent: bypass X2go's keyboard configuration hack

If X2go runs in auto keyboard mode it will pass keyboard=null/null to
the agent and set the keyboard afterwards with setxkbmap. This patch
lets nxagent handle that situation internally (null/null will be
interpreted as clone) and disables X2go's mechanism (by creating a dir
that effectively blocks it; see x2gosetkeyboard)

This is only activated if the agent is run as "x2goagent".

Fixes ArcticaProject/nx-libs#368

3 files changed, 92 insertions, 32 deletions

diff --git a/nx-X11/programs/Xserver/hw/nxagent/Keyboard.c b/nx-X11/programs/Xserver/hw/nxagent/Keyboard.c
index cfe73ac5b..af27c6e28 100644
--- a/nx-X11/programs/Xserver/hw/nxagent/Keyboard.c
+++ b/nx-X11/programs/Xserver/hw/nxagent/Keyboard.c
@@ -57,6 +57,7 @@ is" without express or implied warranty.
 #include "Events.h"
 #include "Options.h"
 #include "Error.h"
+#include "Init.h"
 
 #include "compext/Compext.h"
 
@@ -82,6 +83,7 @@ static void nxagentXkbGetNames(void);
 
 void nxagentKeycodeConversionSetup(void);
 
+static void nxagentWriteKeyboardDir(void);
 static void nxagentWriteKeyboardFile(char *rules, char *model, char *layout, char *variant, char *options);
 
 #endif /* XKB */
@@ -751,6 +753,15 @@ XkbError:
         fprintf(stderr, "nxagentKeyboardProc: nxagentKeyboard is [%s].\n", nxagentKeyboard ? nxagentKeyboard : "NULL");
         #endif
 
+        if (nxagentX2go == 1 && nxagentKeyboard && (strcmp(nxagentKeyboard, "null/null") == 0))
+        {
+          #ifdef TEST
+          fprintf(stderr, "%s: changing nxagentKeyboard from [null/null] to [clone].\n", __func__);
+          #endif
+          free(nxagentKeyboard);
+          nxagentKeyboard = strdup("clone");
+        }
+
         /*
           from nxagent changelog:
           2.0.22:
@@ -846,19 +857,6 @@ XkbError:
                   __func__, nxagentRemoteRules, nxagentRemoteModel, nxagentRemoteLayout, nxagentRemoteVariant, nxagentRemoteOptions);
           #endif
 
-          /*
-           * Keyboard has always been tricky with nxagent. For that
-           * reason X2Go offers "auto" keyboard configuration. You can
-           * specify it in the client side session configuration. In
-           * "auto" mode x2goserver expects nxagent to write the
-           * remote keyboard config to a file on startup and
-           * x2goserver would then pick that file and pass it to
-           * setxkbmap. This functionality is obsoleted by the "clone"
-           * stuff but we still need it because x2goserver does not
-           * know about that yet. Once x2go starts using clone
-           * we can drop this here.
-           */
-          nxagentWriteKeyboardFile(nxagentRemoteRules, nxagentRemoteModel, nxagentRemoteLayout, nxagentRemoteVariant, nxagentRemoteOptions);
 
           /* Only setup keycode conversion if we are NOT in clone mode */
           if (nxagentKeyboard && (strcmp(nxagentKeyboard, "clone") == 0))
@@ -868,10 +866,33 @@ XkbError:
             free(layout); layout = strdup(nxagentRemoteLayout);
             free(variant); variant = strdup(nxagentRemoteVariant);
             free(options); options = strdup(nxagentRemoteOptions);
+            /*
+             * when cloning we do not want X2Go to set the keyboard
+             * via a keyboard file generated by nxagent. The defined
+             * method for switching that off is the creation of a dir
+             * instead of a file. Which is achieved by passing NULL to
+             * nxagentWriteKeyboardFile.
+             */
+            if (nxagentX2go == 1)
+              nxagentWriteKeyboardDir();
           }
           else
           {
             nxagentKeycodeConversionSetup();
+            /*
+             * Keyboard has always been tricky with nxagent. For that
+             * reason X2Go offers "auto" keyboard configuration. You can
+             * specify it in the client side session configuration. In
+             * "auto" mode x2goserver expects nxagent to write the
+             * remote keyboard config to a file on startup and
+             * x2goserver would then pick that file and pass it to
+             * setxkbmap. This functionality is obsoleted by the "clone"
+             * stuff but we still need it because x2goserver does not
+             * know about that yet. Once x2go starts using clone
+             * we can drop this here.
+             */
+            if (nxagentX2go == 1)
+              nxagentWriteKeyboardFile(nxagentRemoteRules, nxagentRemoteModel, nxagentRemoteLayout, nxagentRemoteVariant, nxagentRemoteOptions);
           }
         }
         #ifdef DEBUG
@@ -1645,6 +1666,49 @@ static void writeKeyboardfileData(FILE *out, char *rules, char *model, char *lay
   fprintf(out, "options=\",%s\"\n", options ? options : "");
 }
 
+static char* getKeyboardFilePath(void)
+{
+  char *keyboard_file_path = NULL;
+  char *sessionpath = nxagentGetSessionPath();
+  if (sessionpath)
+  {
+    if ((asprintf(&keyboard_file_path, "%s/keyboard", sessionpath) == -1))
+    {
+      free(sessionpath);
+      FatalError("malloc for keyboard file path failed.");
+    }
+    free(sessionpath);
+  }
+  else
+  {
+    fprintf(stderr, "Warning: Failed to determine keyboard file path: SessionPath not defined\n");
+  }
+  return keyboard_file_path;
+}
+
+static void nxagentWriteKeyboardDir(void)
+{
+  char *keyboard_file_path = getKeyboardFilePath();
+
+  if (keyboard_file_path)
+  {
+    /*
+     * special case: if rules is NULL create a directory insteas of
+     * a file. This is the defined method to disable x2gosetkeyboard.
+     */
+    if (mkdir(keyboard_file_path, 0555) < 0)
+    {
+      int save_err = errno;
+      fprintf(stderr, "Warning: Failed to create keyboard blocking directory '%s': %s\n", keyboard_file_path, strerror(save_err));
+    }
+    else
+    {
+      fprintf(stderr, "Info: keyboard blocking directory created: '%s'\n", keyboard_file_path);
+    }
+    free(keyboard_file_path);
+  }
+}
+
 static void nxagentWriteKeyboardFile(char *rules, char *model, char *layout, char *variant, char *options)
 {
   if (rules && rules[0] != '\0')
@@ -1653,21 +1717,14 @@ static void nxagentWriteKeyboardFile(char *rules, char *model, char *layout, cha
     writeKeyboardfileData(stderr, rules, model, layout, variant, options);
     #endif
 
-    char *sessionpath = nxagentGetSessionPath();
-    if (sessionpath)
+    char *keyboard_file_path = getKeyboardFilePath();
+
+    if (keyboard_file_path)
     {
-      char *keyboard_file_path = NULL;
       FILE *keyboard_file;
-      if ((asprintf(&keyboard_file_path, "%s/keyboard", sessionpath) == -1))
-      {
-        free(sessionpath);
-        FatalError("malloc for keyboard file path failed.");
-      }
-      free(sessionpath);
       if ((keyboard_file = fopen(keyboard_file_path, "w")))
       {
         writeKeyboardfileData(keyboard_file, rules, model, layout, variant, options);
-
         fclose(keyboard_file);
         fprintf(stderr, "Info: keyboard file created: '%s'\n", keyboard_file_path);
       }
@@ -1678,14 +1735,6 @@ static void nxagentWriteKeyboardFile(char *rules, char *model, char *layout, cha
       }
       free(keyboard_file_path);
     }
-    else
-    {
-      fprintf(stderr, "Warning: Failed to create keyboard file: SessionPath not defined\n");
-    }
-  }
-  else
-  {
-    fprintf(stderr, "Warning: Failed to create the keyboard file\n");
   }
 }
 
diff --git a/nx-X11/programs/Xserver/hw/nxagent/Reconnect.c b/nx-X11/programs/Xserver/hw/nxagent/Reconnect.c
index 91445a383..a921df6ca 100644
--- a/nx-X11/programs/Xserver/hw/nxagent/Reconnect.c
+++ b/nx-X11/programs/Xserver/hw/nxagent/Reconnect.c
@@ -458,6 +458,16 @@ Bool nxagentReconnectSession(void)
 
   nxagentProcessOptions(nxagentOptionsFilenameOrString);
 
+  if (nxagentKeyboard && (strcmp(nxagentKeyboard, "null/null") == 0))
+  {
+    #ifdef TEST
+    fprintf(stderr, "nxagentReconnect: changing nxagentKeyboard from [null/null] to [clone].\n");
+    #endif
+
+    free(nxagentKeyboard);
+    nxagentKeyboard = strdup("clone");
+  }
+
   if (nxagentReconnectDisplay(reconnectLossyLevel[DISPLAY_STEP]) == 0)
   {
     failedStep = DISPLAY_STEP;
diff --git a/nx-X11/programs/Xserver/hw/nxagent/man/nxagent.1 b/nx-X11/programs/Xserver/hw/nxagent/man/nxagent.1
index 938c2eb57..737d3609d 100644
--- a/nx-X11/programs/Xserver/hw/nxagent/man/nxagent.1
+++ b/nx-X11/programs/Xserver/hw/nxagent/man/nxagent.1
@@ -623,7 +623,8 @@ protocol functions and clone them. This is the recommended setting. For
 compatibility reasons it is not the default.
 .TP 8
 .I <model>/<layout>
-use the given model and layout. You can not modify keyboard rules,
+use the given model and layout. A value of \fInull/null\fR is equivalent to
+\fIclone\fR. You can not modify keyboard rules,
 variant or options this way. Instead preset values are used. These are
 \fIbase\fR for rules and empty strings for variant and options.
 .TP 8