nxcomp: Duplicate NXTransDialog code as NXTransCallbacksDispatcher.

  - As a starting point for newly implementing a callbacks dispatcher
    scenario that allows capturing various session events and execute
    external tools (like dialog boxes, pulldown menus, etc.).
  - The callbacks dispatch approach will finally deprecated the NX_CLIENT
    env var related code path in later releases of nxcomp/nxagent.

 For now, the callbacks dispatcher code path is taken if the env var
 NX_CALLBACKS_DISPATCHER is set, ideally to the applications that handles
 the dispatching of callbacks from nxagent.

nx-X11/programs/Xserver/hw/nxagent/Dialog.c

@@ -180,6 +180,8 @@ void nxagentLaunchDialog(DialogType dialogType)
   int local;
   const char *window = NULL;
 
+  char *cbDispatcherCmd;
+
   switch (dialogType)
   {
     case DIALOG_KILL_SESSION:
@@ -319,9 +321,14 @@ void nxagentLaunchDialog(DialogType dialogType)
 
   sigprocmask(SIG_BLOCK, &set, &oldSet);
 
-  *pid = NXTransDialog(nxagentDialogName, message, window,
-                           type, local, dialogDisplay);
+  cbDispatcherCmd = getenv("NX_CALLBACKS_DISPATCHER");
 
+  if (cbDispatcherCmd == NULL)
+    *pid = NXTransDialog(nxagentDialogName, message, window,
+                             type, local, dialogDisplay);
+  else
+    *pid = NXTransCallbacksDispatcher(nxagentDialogName, message, window,
+                             type, local, dialogDisplay);
   #ifdef TEST
   fprintf(stderr, "nxagentLaunchDialog: Launched dialog %s with pid [%d] on display %s.\n",
               DECODE_DIALOG_TYPE(dialogType), *pid, dialogDisplay);

nxcomp/Children.cpp

@@ -108,6 +108,225 @@ static int NXTransKeeperHandler(int signal);
 static void NXTransKeeperCheck();
 
 
+int NXTransCallbacksDispatcher(const char *caption, const char *message,
+                                   const char *window, const char *type, int local,
+                                       const char* display)
+{
+  //
+  // Be sure log file is valid.
+  //
+
+  if (logofs == NULL)
+  {
+    logofs = &cerr;
+  }
+
+  int pid;
+
+  #ifdef TEST
+  *logofs << "NXTransCallbacksDispatcher: Going to fork with NX pid '"
+          << getpid() << "'.\n" << logofs_flush;
+  #endif
+
+  pid = Fork();
+
+  if (pid != 0)
+  {
+    if (pid < 0)
+    {
+      #ifdef TEST
+      *logofs << "NXTransCallbacksDispatcher: WARNING! Function fork failed. "
+              << "Error is " << EGET() << " '" << ESTR()
+              << "'.\n" << logofs_flush;
+      #endif
+
+      cerr << "Warning" << ": Function fork failed. "
+           << "Error is " << EGET() << " '" << ESTR()
+           << "'.\n";
+    }
+    #ifdef TEST
+    else
+    {
+      *logofs << "NXTransCallbacksDispatcher: Created NX dialog process "
+              << "with pid '" << pid << "'.\n"
+              << logofs_flush;
+    }
+    #endif
+
+    return pid;
+  }
+
+  #ifdef TEST
+  *logofs << "NXTransCallbacksDispatcher: Executing child with pid '"
+          << getpid() << "' and parent '" << getppid()
+          << "'.\n" << logofs_flush;
+  #endif
+
+  SystemCleanup("NXTransCallbacksDispatcher");
+
+  //
+  // Copy the client command before
+  // freeing up the control class.
+  //
+
+  char command[DEFAULT_STRING_LIMIT];
+
+  if (control != NULL)
+  {
+    strcpy(command, control -> ClientPath);
+  }
+  else
+  {
+    char *path = GetClientPath();
+
+    strcpy(command, path);
+
+    delete [] path;
+  }
+
+  //
+  // Get rid of the unused resources.
+  //
+
+  MemoryCleanup("NXTransCallbacksDispatcher");
+
+  #ifdef TEST
+  *logofs << "NXTransCallbacksDispatcher: Running external NX dialog with caption '"
+          << caption << "' message '" << message << "' type '"
+          << type << "' local '" << local << "' display '"
+          << display << "'.\n"
+          << logofs_flush;
+  #endif
+
+  int pulldown = (strcmp(type, "pulldown") == 0);
+
+  char parent[DEFAULT_STRING_LIMIT];
+
+  snprintf(parent, DEFAULT_STRING_LIMIT, "%d", getppid());
+
+  parent[DEFAULT_STRING_LIMIT - 1] = '\0';
+
+  UnsetEnv("LD_LIBRARY_PATH");
+
+  for (int i = 0; i < 2; i++)
+  {
+    if (local != 0)
+    {
+      if (pulldown)
+      {
+        execlp(command, command, "--dialog", type, "--caption", caption,
+                   "--window", window, "--local", "--parent", parent,
+                       "--display", display, NULL);
+      }
+      else
+      {
+        execlp(command, command, "--dialog", type, "--caption", caption,
+                   "--message", message, "--local", "--parent", parent,
+                       "--display", display, NULL);
+      }
+    }
+    else
+    {
+      if (pulldown)
+      {
+        execlp(command, command, "--dialog", type, "--caption", caption,
+                   "--window", window, "--parent", parent,
+                       "--display", display, NULL);
+      }
+      else
+      {
+        execlp(command, command, "--dialog", type, "--caption", caption,
+                   "--message", message, "--parent", parent,
+                       "--display", display, NULL);
+      }
+    }
+
+    #ifdef WARNING
+    *logofs << "NXTransCallbacksDispatcher: WARNING! Couldn't start '"
+            << command << "'. " << "Error is " << EGET()
+            << " '" << ESTR() << "'.\n" << logofs_flush;
+    #endif
+
+    cerr << "Warning" << ": Couldn't start '" << command
+         << "'. Error is " << EGET() << " '" << ESTR()
+         << "'.\n";
+
+    //
+    // Retry by looking for the default name
+    // in the default NX path.
+    //
+
+    if (i == 0)
+    {
+
+      strcpy(command, "nxclient");
+
+      char newPath[DEFAULT_STRING_LIMIT];
+
+      strcpy(newPath, "/usr/NX/bin:/opt/NX/bin:/usr/local/NX/bin:");
+
+      #ifdef __APPLE__
+
+      strcat(newPath, "/Applications/NX Client for OSX.app/Contents/MacOS:");
+
+      #endif
+
+      #ifdef __CYGWIN32__
+
+      strcat(newPath, ".:");
+
+      #endif
+
+      int newLength = strlen(newPath);
+
+      char *oldPath = getenv("PATH");
+
+      strncpy(newPath + newLength, oldPath, DEFAULT_STRING_LIMIT - newLength - 1);
+
+      newPath[DEFAULT_STRING_LIMIT - 1] = '\0';
+
+      #ifdef WARNING
+      *logofs << "NXTransCallbacksDispatcher: WARNING! Trying with path '"
+              << newPath << "'.\n" << logofs_flush;
+      #endif
+
+      cerr << "Warning" << ": Trying with path '" << newPath
+           << "'.\n";
+
+      //
+      // Solaris doesn't seem to have
+      // function setenv().
+      //
+
+      #ifdef __sun
+
+      char newEnv[DEFAULT_STRING_LIMIT + 5];
+
+      sprintf(newEnv,"PATH=%s", newPath);
+
+      putenv(newEnv);
+
+      #else
+
+      setenv("PATH", newPath, 1);
+
+      #endif
+
+    }
+  }
+
+  //
+  // Hopefully useless.
+  //
+
+  exit(0);
+}
+
+//
+// Start a nxclient process in dialog mode.
+//
+
+
 //
 // Start a nxclient process in dialog mode.
 //

nxcomp/NX.h

@@ -433,6 +433,10 @@ extern int NXTransProxy(int fd, int mode, const char *display);
 
 extern int NXTransClient(const char *display);
 
+extern int NXTransCallbacksDispatcher(const char *caption, const char *message,
+                                        const char *window, const char *type, int local,
+                                          const char *display);
+
 extern int NXTransDialog(const char *caption, const char *message,
                            const char *window, const char *type, int local,
                                const char *display);