Clean up shutdown process

1 files changed, 93 insertions, 100 deletions

diff --git a/src/init.cpp b/src/init.cpp
index a2e85f2ef2..3ccd01e3bc 100644
--- a/src/init.cpp
+++ b/src/init.cpp
@@ -40,75 +40,65 @@ enum BindFlags {
 // Shutdown
 //
 
-void ExitTimeout(void* parg)
-{
-#ifdef WIN32
-    MilliSleep(5000);
-    ExitProcess(0);
-#endif
-}
+//
+// Thread management and startup/shutdown:
+//
+// The network-processing threads are all part of a thread group
+// created by AppInit() or the Qt main() function.
+//
+// A clean exit happens when StartShutdown() or the SIGTERM
+// signal handler sets fRequestShutdown, which triggers
+// the DetectShutdownThread(), which interrupts the main thread group.
+// DetectShutdownThread() then exits, which causes AppInit() to
+// continue (it .joins the shutdown thread).
+// Shutdown() is then
+// called to clean up database connections, and stop other
+// threads that should only be stopped after the main network-processing
+// threads have exited.
+//
+// Note that if running -daemon the parent process returns from AppInit2
+// before adding any threads to the threadGroup, so .join_all() returns
+// immediately and the parent exits from main().
+//
+// Shutdown for Qt is very similar, only it uses a QTimer to detect
+// fRequestShutdown getting set (either by RPC stop or SIGTERM)
+// and then does the normal Qt shutdown thing.
+//
+
+volatile bool fRequestShutdown = false;
 
 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
-    NewThread(Shutdown, NULL);
-#endif
+    fRequestShutdown = true;
 }
 
 static CCoinsViewDB *pcoinsdbview;
 
-void Shutdown(void* parg)
+void Shutdown()
 {
     static CCriticalSection cs_Shutdown;
-    static bool fTaken;
+    TRY_LOCK(cs_Shutdown, lockShutdown);
+    if (!lockShutdown) return;
 
-    // Make this thread recognisable as the shutdown thread
     RenameThread("bitcoin-shutoff");
     nTransactionsUpdated++;
     StopRPCThreads();
     bitdb.Flush(false);
     StopNode();
     {
-        fShutdown = true;
-        fRequestShutdown = true;
-        nTransactionsUpdated++;
-        StopRPCThreads();
-        bitdb.Flush(false);
-        StopNode();
-        {
-            LOCK(cs_main);
-            if (pblocktree)
-                pblocktree->Flush();
-            if (pcoinsTip)
-                pcoinsTip->Flush();
-            delete pcoinsTip;
-            delete pcoinsdbview;
-            delete pblocktree;
-        }
-        bitdb.Flush(true);
-        boost::filesystem::remove(GetPidFile());
-        UnregisterWallet(pwalletMain);
-        delete pwalletMain;
-        NewThread(ExitTimeout, NULL);
-        MilliSleep(50);
-        printf("Bitcoin exited\n\n");
-        fExit = true;
-#ifndef QT_GUI
-        // ensure non-UI client gets exited here, but let Bitcoin-Qt reach 'return 0;' in bitcoin.cpp
-        exit(0);
-#endif
-    }
-    else
-    {
-        while (!fExit)
-            MilliSleep(500);
-        MilliSleep(100);
-        ExitThread(0);
+        LOCK(cs_main);
+        if (pblocktree)
+            pblocktree->Flush();
+        if (pcoinsTip)
+            pcoinsTip->Flush();
+        delete pcoinsTip; pcoinsTip = NULL;
+        delete pcoinsdbview; pcoinsdbview = NULL;
+        delete pblocktree; pblocktree = NULL;
     }
+    bitdb.Flush(true);
+    boost::filesystem::remove(GetPidFile());
+    UnregisterWallet(pwalletMain);
+    delete pwalletMain;
 }
 
 //
@@ -116,9 +106,13 @@ void Shutdown(void* parg)
 //
 void DetectShutdownThread(boost::thread_group* threadGroup)
 {
-    while (fRequestShutdown == false)
+    // Tell the main threads to shutdown.
+    while (!fRequestShutdown)
+    {
         MilliSleep(200);
-    threadGroup->interrupt_all();
+        if (fRequestShutdown)
+            threadGroup->interrupt_all();
+    }
 }
 
 void HandleSIGTERM(int)
@@ -143,6 +137,8 @@ void HandleSIGHUP(int)
 bool AppInit(int argc, char* argv[])
 {
     boost::thread_group threadGroup;
+    boost::thread* detectShutdownThread = NULL;
+
     bool fRet = false;
     try
     {
@@ -154,7 +150,7 @@ bool AppInit(int argc, char* argv[])
         if (!boost::filesystem::is_directory(GetDataDir(false)))
         {
             fprintf(stderr, "Error: Specified directory does not exist\n");
-            Shutdown(NULL);
+            Shutdown();
         }
         ReadConfigFile(mapArgs, mapMultiArgs);
 
@@ -184,7 +180,31 @@ bool AppInit(int argc, char* argv[])
             int ret = CommandLineRPC(argc, argv);
             exit(ret);
         }
+#if !defined(WIN32)
+        fDaemon = GetBoolArg("-daemon");
+        if (fDaemon)
+        {
+            // Daemonize
+            pid_t pid = fork();
+            if (pid < 0)
+            {
+                fprintf(stderr, "Error: fork() returned %d errno %d\n", pid, errno);
+                return false;
+            }
+            if (pid > 0) // Parent process, pid is child process id
+            {
+                CreatePidFile(GetPidFile(), pid);
+                return true;
+            }
+            // Child process falls through to rest of initialization
+
+            pid_t sid = setsid();
+            if (sid < 0)
+                fprintf(stderr, "Error: setsid() returned %d errno %d\n", sid, errno);
+        }
+#endif
 
+        detectShutdownThread = new boost::thread(boost::bind(&DetectShutdownThread, &threadGroup));
         fRet = AppInit2(threadGroup);
     }
     catch (std::exception& e) {
@@ -192,12 +212,20 @@ bool AppInit(int argc, char* argv[])
     } catch (...) {
         PrintExceptionContinue(NULL, "AppInit()");
     }
-    if (!fRet)
+    if (!fRet) {
+      if (detectShutdownThread)
+        detectShutdownThread->interrupt();
+      threadGroup.interrupt_all();
+    }
+
+    if (detectShutdownThread)
     {
-        Shutdown(NULL);
-        threadGroup.interrupt_all();
-        threadGroup.join_all();
+        detectShutdownThread->join();
+        delete detectShutdownThread;
+	detectShutdownThread = NULL;
     }
+    Shutdown();
+
     return fRet;
 }
 
@@ -214,7 +242,7 @@ int main(int argc, char* argv[])
     if (fRet && fDaemon)
         return 0;
 
-    return 1;
+    return (fRet ? 0 : 1);
 }
 #endif
 
@@ -302,7 +330,7 @@ std::string HelpMessage()
         "  -rpcport=<port>        " + _("Listen for JSON-RPC connections on <port> (default: 8332 or testnet: 18332)") + "\n" +
         "  -rpcallowip=<ip>       " + _("Allow JSON-RPC connections from specified IP address") + "\n" +
         "  -rpcconnect=<ip>       " + _("Send commands to node running on <ip> (default: 127.0.0.1)") + "\n" +
-        "  -rpcthreads=<n>        " + _("Use this mean threads to service RPC calls (default: 4)") + "\n" +
+        "  -rpcthreads=<n>        " + _("Use this many threads to service RPC calls (default: 4)") + "\n" +
         "  -blocknotify=<cmd>     " + _("Execute command when the best block changes (%s in cmd is replaced by block hash)") + "\n" +
         "  -walletnotify=<cmd>    " + _("Execute command when a wallet transaction changes (%s in cmd is replaced by TxID)") + "\n" +
         "  -alertnotify=<cmd>     " + _("Execute command when a relevant alert is received (%s in cmd is replaced by message)") + "\n" +
@@ -440,8 +468,6 @@ bool AppInit2(boost::thread_group& threadGroup)
     sigaction(SIGHUP, &sa_hup, NULL);
 #endif
 
-    threadGroup.create_thread(boost::bind(&DetectShutdownThread, &threadGroup));
-
     // ********************************************************* Step 2: parameter interactions
 
     fTestNet = GetBoolArg("-testnet");
@@ -499,12 +525,6 @@ bool AppInit2(boost::thread_group& threadGroup)
     else
         fDebugNet = GetBoolArg("-debugnet");
 
-#if !defined(WIN32) && !defined(QT_GUI)
-    fDaemon = GetBoolArg("-daemon");
-#else
-    fDaemon = false;
-#endif
-
     if (fDaemon)
         fServer = true;
     else
@@ -552,28 +572,6 @@ bool AppInit2(boost::thread_group& threadGroup)
     if (!lock.try_lock())
         return InitError(strprintf(_("Cannot obtain a lock on data directory %s. Bitcoin is probably already running."), strDataDir.c_str()));
 
-#if !defined(WIN32) && !defined(QT_GUI)
-    if (fDaemon)
-    {
-        // Daemonize
-        pid_t pid = fork();
-        if (pid < 0)
-        {
-            fprintf(stderr, "Error: fork() returned %d errno %d\n", pid, errno);
-            return false;
-        }
-        if (pid > 0)
-        {
-            CreatePidFile(GetPidFile(), pid);
-            return true;
-        }
-
-        pid_t sid = setsid();
-        if (sid < 0)
-            fprintf(stderr, "Error: setsid() returned %d errno %d\n", sid, errno);
-    }
-#endif
-
     if (GetBoolArg("-shrinkdebugfile", !fDebug))
         ShrinkDebugFile();
     printf("\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n");
@@ -1011,8 +1009,7 @@ bool AppInit2(boost::thread_group& threadGroup)
     printf("mapWallet.size() = %"PRIszu"\n",       pwalletMain->mapWallet.size());
     printf("mapAddressBook.size() = %"PRIszu"\n",  pwalletMain->mapAddressBook.size());
 
-    if (!NewThread(StartNode, (void*)&threadGroup))
-        InitError(_("Error: could not start node"));
+    StartNode(threadGroup);
 
     if (fServer)
         StartRPCThreads();
@@ -1030,12 +1027,8 @@ bool AppInit2(boost::thread_group& threadGroup)
      // Add wallet transactions that aren't already in a block to mapTransactions
     pwalletMain->ReacceptWalletTransactions();
 
-#if !defined(QT_GUI)
-    // Loop until process is exit()ed from shutdown() function,
-    // called from ThreadRPCServer thread when a "stop" command is received.
-    while (1)
-        MilliSleep(5000);
-#endif
+    // Run a thread to flush wallet periodically
+    threadGroup.create_thread(boost::bind(&ThreadFlushWalletDB, boost::ref(pwalletMain->strWalletFile)));
 
-    return true;
+    return !fRequestShutdown;
 }