Eliminate data races for strMiscWarning and fLargeWork*Found.

This moves all access to these datastructures through accessor functions
 and protects them with a lock.

src/timedata.cpp

@@ -103,8 +103,8 @@ void AddTimeData(const CNetAddr& ip, int64_t nOffsetSample)
                 if (!fMatch)
                 {
                     fDone = true;
-                    string strMessage = strprintf(_("Please check that your computer's date and time are correct! If your clock is wrong, %s will not work properly."), _(PACKAGE_NAME));
+                    std::string strMessage = strprintf(_("Please check that your computer's date and time are correct! If your clock is wrong, %s will not work properly."), _(PACKAGE_NAME));
-                    strMiscWarning = strMessage;
+                    SetMiscWarning(strMessage);
                     uiInterface.ThreadSafeMessageBox(strMessage, "", CClientUIInterface::MSG_WARNING);
                 }
             }

src/util.cpp

@@ -108,6 +108,7 @@ bool fDebug = false;
 bool fPrintToConsole = false;
 bool fPrintToDebugLog = true;
 
+CCriticalSection cs_warnings;
 string strMiscWarning;
 bool fLargeWorkForkFound = false;
 bool fLargeWorkInvalidChainFound = false;
@@ -813,6 +814,36 @@ std::string CopyrightHolders(const std::string& strPrefix)
     return strCopyrightHolders;
 }
 
+void SetMiscWarning(const std::string& strWarning)
+{
+    LOCK(cs_warnings);
+    strMiscWarning = strWarning;
+}
+
+void SetfLargeWorkForkFound(bool flag)
+{
+    LOCK(cs_warnings);
+    fLargeWorkForkFound = flag;
+}
+
+bool GetfLargeWorkForkFound()
+{
+    LOCK(cs_warnings);
+    return fLargeWorkForkFound;
+}
+
+void SetfLargeWorkInvalidChainFound(bool flag)
+{
+    LOCK(cs_warnings);
+    fLargeWorkInvalidChainFound = flag;
+}
+
+bool GetfLargeWorkInvalidChainFound()
+{
+    LOCK(cs_warnings);
+    return fLargeWorkInvalidChainFound;
+}
+
 std::string GetWarnings(const std::string& strFor)
 {
     string strStatusBar;
@@ -820,6 +851,8 @@ std::string GetWarnings(const std::string& strFor)
     string strGUI;
     const string uiAlertSeperator = "<hr />";
 
+    LOCK(cs_warnings);
+
     if (!CLIENT_VERSION_IS_RELEASE) {
         strStatusBar = "This is a pre-release test build - use at your own risk - do not use for mining or merchant applications";
         strGUI = _("This is a pre-release test build - use at your own risk - do not use for mining or merchant applications");

src/util.h

@@ -48,9 +48,6 @@ extern bool fPrintToConsole;
 extern bool fPrintToDebugLog;
 
 static const bool DEFAULT_TESTSAFEMODE = false;
-extern std::string strMiscWarning;
-extern bool fLargeWorkForkFound;
-extern bool fLargeWorkInvalidChainFound;
 
 extern bool fLogTimestamps;
 extern bool fLogTimeMicros;
@@ -229,6 +226,11 @@ template <typename Callable> void TraceThread(const char* name,  Callable func)
 
 std::string CopyrightHolders(const std::string& strPrefix);
 
+void SetMiscWarning(const std::string& strWarning);
+void SetfLargeWorkForkFound(bool flag);
+bool GetfLargeWorkForkFound();
+void SetfLargeWorkInvalidChainFound(bool flag);
+bool GetfLargeWorkInvalidChainFound();
 std::string GetWarnings(const std::string& strFor);
 
 #endif // BITCOIN_UTIL_H

src/validation.cpp

@@ -1183,7 +1183,7 @@ void CheckForkWarningConditions()
 
     if (pindexBestForkTip || (pindexBestInvalid && pindexBestInvalid->nChainWork > chainActive.Tip()->nChainWork + (GetBlockProof(*chainActive.Tip()) * 6)))
     {
-        if (!fLargeWorkForkFound && pindexBestForkBase)
+        if (!GetfLargeWorkForkFound() && pindexBestForkBase)
         {
             std::string warning = std::string("'Warning: Large-work fork detected, forking after block ") +
                 pindexBestForkBase->phashBlock->ToString() + std::string("'");
@@ -1194,18 +1194,18 @@ void CheckForkWarningConditions()
             LogPrintf("%s: Warning: Large valid fork found\n  forking the chain at height %d (%s)\n  lasting to height %d (%s).\nChain state database corruption likely.\n", __func__,
                    pindexBestForkBase->nHeight, pindexBestForkBase->phashBlock->ToString(),
                    pindexBestForkTip->nHeight, pindexBestForkTip->phashBlock->ToString());
-            fLargeWorkForkFound = true;
+            SetfLargeWorkForkFound(true);
         }
         else
         {
             LogPrintf("%s: Warning: Found invalid chain at least ~6 blocks longer than our best chain.\nChain state database corruption likely.\n", __func__);
-            fLargeWorkInvalidChainFound = true;
+            SetfLargeWorkInvalidChainFound(true);
         }
     }
     else
     {
-        fLargeWorkForkFound = false;
+        SetfLargeWorkForkFound(false);
-        fLargeWorkInvalidChainFound = false;
+        SetfLargeWorkInvalidChainFound(false);
     }
 }
 
@@ -1481,7 +1481,7 @@ bool UndoReadFromDisk(CBlockUndo& blockundo, const CDiskBlockPos& pos, const uin
 /** Abort with a message */
 bool AbortNode(const std::string& strMessage, const std::string& userMessage="")
 {
-    strMiscWarning = strMessage;
+    SetMiscWarning(strMessage);
     LogPrintf("*** %s\n", strMessage);
     uiInterface.ThreadSafeMessageBox(
         userMessage.empty() ? _("Error: A fatal internal error occurred, see debug.log for details") : userMessage,
@@ -2050,9 +2050,10 @@ void static UpdateTip(CBlockIndex *pindexNew, const CChainParams& chainParams) {
             ThresholdState state = checker.GetStateFor(pindex, chainParams.GetConsensus(), warningcache[bit]);
             if (state == THRESHOLD_ACTIVE || state == THRESHOLD_LOCKED_IN) {
                 if (state == THRESHOLD_ACTIVE) {
-                    strMiscWarning = strprintf(_("Warning: unknown new rules activated (versionbit %i)"), bit);
+                    std::string strWarning = strprintf(_("Warning: unknown new rules activated (versionbit %i)"), bit);
+                    SetMiscWarning(strWarning);
                     if (!fWarned) {
-                        AlertNotify(strMiscWarning);
+                        AlertNotify(strWarning);
                         fWarned = true;
                     }
                 } else {
@@ -2072,10 +2073,11 @@ void static UpdateTip(CBlockIndex *pindexNew, const CChainParams& chainParams) {
             warningMessages.push_back(strprintf("%d of last 100 blocks have unexpected version", nUpgraded));
         if (nUpgraded > 100/2)
         {
-            // strMiscWarning is read by GetWarnings(), called by Qt and the JSON-RPC code to warn the user:
+            std::string strWarning = _("Warning: Unknown block versions being mined! It's possible unknown rules are in effect");
-            strMiscWarning = _("Warning: Unknown block versions being mined! It's possible unknown rules are in effect");
+            // notify GetWarnings(), called by Qt and the JSON-RPC code to warn the user:
+            SetMiscWarning(strWarning);
             if (!fWarned) {
-                AlertNotify(strMiscWarning);
+                AlertNotify(strWarning);
                 fWarned = true;
             }
         }