introduce a new StartShutdown() function, which starts a thread with Shutdown() if no GUI is used and calls uiInterface.QueueShutdown() if a GUI is used / all direct uiInterface.QueueShutdown() calls are replaced with Shutdown() - this ensures a clean GUI shutdown, even when catching a SIGTERM and allows the BitcoinGUI destructor to get called (which fixes a tray-icon issue and keeps the tray-icon until Bitcoin-Qt exits)

src/bitcoinrpc.cpp

@@ -436,7 +436,7 @@ Value stop(const Array& params, bool fHelp)
             "stop\n"
             "Stop Bitcoin server.");
     // Shutdown will take long enough that the response should get back
-    uiInterface.QueueShutdown();
+    StartShutdown();
     return "Bitcoin server stopping";
 }
 
@@ -1935,7 +1935,7 @@ Value encryptwallet(const Array& params, bool fHelp)
     // BDB seems to have a bad habit of writing old data into
     // slack space in .dat files; that is bad if the old data is
     // unencrypted private keys.  So:
-    uiInterface.QueueShutdown();
+    StartShutdown();
     return "wallet encrypted; Bitcoin server stopping, restart to run with encrypted wallet";
 }
 
@@ -2682,7 +2682,7 @@ void ThreadRPCServer2(void* parg)
                 GetConfigFile().string().c_str(),
                 EncodeBase58(&rand_pwd[0],&rand_pwd[0]+32).c_str()),
             _("Error"), CClientUIInterface::OK | CClientUIInterface::MODAL);
-        uiInterface.QueueShutdown();
+        StartShutdown();
         return;
     }
 
@@ -2703,7 +2703,7 @@ void ThreadRPCServer2(void* parg)
     {
         uiInterface.ThreadSafeMessageBox(strprintf(_("An error occured while setting up the RPC port %i for listening: %s"), endpoint.port(), e.what()),
                              _("Error"), CClientUIInterface::OK | CClientUIInterface::MODAL);
-        uiInterface.QueueShutdown();
+        StartShutdown();
         return;
     }
 

src/init.cpp

@@ -38,6 +38,17 @@ void ExitTimeout(void* parg)
 #endif
 }
 
+void StartShutdown()
+{
+#ifdef QT_GUI
+    // ensure we leave the Qt main loop for a clean GUI exit (Shutdown() is called in bitcoin.cpp afterwards)
+    uiInterface.QueueShutdown();
+#else
+    // Without UI, Shutdown() can simply be started in a new thread
+    CreateThread(Shutdown, NULL);
+#endif
+}
+
 void Shutdown(void* parg)
 {
     static CCriticalSection cs_Shutdown;
@@ -66,7 +77,10 @@ void Shutdown(void* parg)
         Sleep(50);
         printf("Bitcoin exited\n\n");
         fExit = true;
+#ifndef QT_GUI
+        // ensure non UI client get's exited here, but let Bitcoin-Qt reach return 0; in bitcoin.cpp
         exit(0);
+#endif
     }
     else
     {

src/init.h

@@ -9,6 +9,7 @@
 
 extern CWallet* pwalletMain;
 
+void StartShutdown();
 void Shutdown(void* parg);
 bool AppInit2();
 std::string HelpMessage();

src/main.cpp

@@ -1875,7 +1875,7 @@ bool CheckDiskSpace(uint64 nAdditionalBytes)
         strMiscWarning = strMessage;
         printf("*** %s\n", strMessage.c_str());
         uiInterface.ThreadSafeMessageBox(strMessage, "Bitcoin", CClientUIInterface::OK | CClientUIInterface::ICON_EXCLAMATION | CClientUIInterface::MODAL);
-        uiInterface.QueueShutdown();
+        StartShutdown();
         return false;
     }
     return true;

src/net.cpp

@@ -1658,7 +1658,7 @@ void ThreadMessageHandler2(void* parg)
         vnThreadsRunning[THREAD_MESSAGEHANDLER]--;
         Sleep(100);
         if (fRequestShutdown)
-            Shutdown(NULL);
+            StartShutdown();
         vnThreadsRunning[THREAD_MESSAGEHANDLER]++;
         if (fShutdown)
             return;

src/noui.cpp

@@ -20,16 +20,9 @@ static bool noui_ThreadSafeAskFee(int64 nFeeRequired, const std::string& strCapt
     return true;
 }
 
-static void noui_QueueShutdown()
-{
-    // Without UI, Shutdown can simply be started in a new thread
-    CreateThread(Shutdown, NULL);
-}
-
 void noui_connect()
 {
     // Connect bitcoind signal handlers
     uiInterface.ThreadSafeMessageBox.connect(noui_ThreadSafeMessageBox);
     uiInterface.ThreadSafeAskFee.connect(noui_ThreadSafeAskFee);
-    uiInterface.QueueShutdown.connect(noui_QueueShutdown);
 }

src/qt/bitcoin.cpp

@@ -290,6 +290,7 @@ int main(int argc, char *argv[])
                 window.setWalletModel(0);
                 guiref = 0;
             }
+            // Shutdown the core and it's threads, but don't exit Bitcoin-Qt here
             Shutdown(NULL);
         }
         else