Merge #9236: Fix races for strMiscWarning and fLargeWork*Found, make QT runawayException use GetWarnings

749be01 Move GetWarnings() into its own file. (Gregory Maxwell)
e3ba0ef Eliminate data races for strMiscWarning and fLargeWork*Found. (Gregory Maxwell)
c63198f Make QT runawayException call GetWarnings instead of directly access strMiscWarning. (Gregory Maxwell)

10 files changed, 138 insertions, 64 deletions

diff --git a/src/Makefile.am b/src/Makefile.am
index 389be6c058..c7124c3ef9 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -155,6 +155,7 @@ BITCOIN_CORE_H = \
   wallet/rpcwallet.h \
   wallet/wallet.h \
   wallet/walletdb.h \
+  warnings.h \
   zmq/zmqabstractnotifier.h \
   zmq/zmqconfig.h\
   zmq/zmqnotificationinterface.h \
@@ -306,6 +307,7 @@ libbitcoin_common_a_SOURCES = \
   scheduler.cpp \
   script/sign.cpp \
   script/standard.cpp \
+  warnings.cpp \
   $(BITCOIN_CORE_H)
 
 # util: shared between all executables.
diff --git a/src/init.cpp b/src/init.cpp
index c5dc9578e7..e642729a99 100644
--- a/src/init.cpp
+++ b/src/init.cpp
@@ -41,6 +41,7 @@
 #ifdef ENABLE_WALLET
 #include "wallet/wallet.h"
 #endif
+#include "warnings.h"
 #include <stdint.h>
 #include <stdio.h>
 #include <memory>
diff --git a/src/qt/bitcoin.cpp b/src/qt/bitcoin.cpp
index 4f48e21a22..cfd0955a74 100644
--- a/src/qt/bitcoin.cpp
+++ b/src/qt/bitcoin.cpp
@@ -30,6 +30,7 @@
 #include "scheduler.h"
 #include "ui_interface.h"
 #include "util.h"
+#include "warnings.h"
 
 #ifdef ENABLE_WALLET
 #include "wallet/wallet.h"
@@ -260,7 +261,7 @@ BitcoinCore::BitcoinCore():
 void BitcoinCore::handleRunawayException(const std::exception *e)
 {
     PrintExceptionContinue(e, "Runaway exception");
-    Q_EMIT runawayException(QString::fromStdString(strMiscWarning));
+    Q_EMIT runawayException(QString::fromStdString(GetWarnings("gui")));
 }
 
 void BitcoinCore::initialize()
@@ -691,10 +692,10 @@ int main(int argc, char *argv[])
         app.exec();
     } catch (const std::exception& e) {
         PrintExceptionContinue(&e, "Runaway exception");
-        app.handleRunawayException(QString::fromStdString(strMiscWarning));
+        app.handleRunawayException(QString::fromStdString(GetWarnings("gui")));
     } catch (...) {
         PrintExceptionContinue(NULL, "Runaway exception");
-        app.handleRunawayException(QString::fromStdString(strMiscWarning));
+        app.handleRunawayException(QString::fromStdString(GetWarnings("gui")));
     }
     return app.getReturnValue();
 }
diff --git a/src/timedata.cpp b/src/timedata.cpp
index 25fc494121..b3cbdcf883 100644
--- a/src/timedata.cpp
+++ b/src/timedata.cpp
@@ -13,6 +13,7 @@
 #include "ui_interface.h"
 #include "util.h"
 #include "utilstrencodings.h"
+#include "warnings.h"
 
 #include <boost/foreach.hpp>
 
@@ -103,8 +104,8 @@ 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));
-                    strMiscWarning = strMessage;
+                    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));
+                    SetMiscWarning(strMessage);
                     uiInterface.ThreadSafeMessageBox(strMessage, "", CClientUIInterface::MSG_WARNING);
                 }
             }
diff --git a/src/util.cpp b/src/util.cpp
index 60701e7949..977f8993ed 100644
--- a/src/util.cpp
+++ b/src/util.cpp
@@ -107,7 +107,7 @@ map<string, vector<string> > mapMultiArgs;
 bool fDebug = false;
 bool fPrintToConsole = false;
 bool fPrintToDebugLog = true;
-string strMiscWarning;
+
 bool fLogTimestamps = DEFAULT_LOGTIMESTAMPS;
 bool fLogTimeMicros = DEFAULT_LOGTIMEMICROS;
 bool fLogIPs = DEFAULT_LOGIPS;
diff --git a/src/util.h b/src/util.h
index e8aa266f28..3ec38a7c7d 100644
--- a/src/util.h
+++ b/src/util.h
@@ -46,7 +46,7 @@ extern std::map<std::string, std::vector<std::string> > mapMultiArgs;
 extern bool fDebug;
 extern bool fPrintToConsole;
 extern bool fPrintToDebugLog;
-extern std::string strMiscWarning;
+
 extern bool fLogTimestamps;
 extern bool fLogTimeMicros;
 extern bool fLogIPs;
diff --git a/src/validation.cpp b/src/validation.cpp
index 02c047f1d4..0f5975922b 100644
--- a/src/validation.cpp
+++ b/src/validation.cpp
@@ -34,6 +34,7 @@
 #include "utilstrencodings.h"
 #include "validationinterface.h"
 #include "versionbits.h"
+#include "warnings.h"
 
 #include <atomic>
 #include <sstream>
@@ -1141,8 +1142,6 @@ bool IsInitialBlockDownload()
     return false;
 }
 
-bool fLargeWorkForkFound = false;
-bool fLargeWorkInvalidChainFound = false;
 CBlockIndex *pindexBestForkTip = NULL, *pindexBestForkBase = NULL;
 
 static void AlertNotify(const std::string& strMessage)
@@ -1177,7 +1176,7 @@ 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("'");
@@ -1188,18 +1187,18 @@ 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;
-        fLargeWorkInvalidChainFound = false;
+        SetfLargeWorkForkFound(false);
+        SetfLargeWorkInvalidChainFound(false);
     }
 }
 
@@ -1475,7 +1474,7 @@ 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,
@@ -2044,9 +2043,10 @@ 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 {
@@ -2066,10 +2066,11 @@ 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:
-            strMiscWarning = _("Warning: Unknown block versions being mined! It's possible unknown rules are in effect");
+            std::string strWarning = _("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;
             }
         }
@@ -4010,51 +4011,10 @@ void static CheckBlockIndex(const Consensus::Params& consensusParams)
     assert(nNodes == forward.size());
 }
 
-std::string GetWarnings(const std::string& strFor)
+std::string CBlockFileInfo::ToString() const
 {
-    string strStatusBar;
-    string strRPC;
-    string strGUI;
-    const string uiAlertSeperator = "<hr />";
-
-    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");
-    }
-
-    if (GetBoolArg("-testsafemode", DEFAULT_TESTSAFEMODE))
-        strStatusBar = strRPC = strGUI = "testsafemode enabled";
-
-    // Misc warnings like out of disk space and clock is wrong
-    if (strMiscWarning != "")
-    {
-        strStatusBar = strMiscWarning;
-        strGUI += (strGUI.empty() ? "" : uiAlertSeperator) + strMiscWarning;
-    }
-
-    if (fLargeWorkForkFound)
-    {
-        strStatusBar = strRPC = "Warning: The network does not appear to fully agree! Some miners appear to be experiencing issues.";
-        strGUI += (strGUI.empty() ? "" : uiAlertSeperator) + _("Warning: The network does not appear to fully agree! Some miners appear to be experiencing issues.");
-    }
-    else if (fLargeWorkInvalidChainFound)
-    {
-        strStatusBar = strRPC = "Warning: We do not appear to fully agree with our peers! You may need to upgrade, or other nodes may need to upgrade.";
-        strGUI += (strGUI.empty() ? "" : uiAlertSeperator) + _("Warning: We do not appear to fully agree with our peers! You may need to upgrade, or other nodes may need to upgrade.");
-    }
-
-    if (strFor == "gui")
-        return strGUI;
-    else if (strFor == "statusbar")
-        return strStatusBar;
-    else if (strFor == "rpc")
-        return strRPC;
-    assert(!"GetWarnings(): invalid parameter");
-    return "error";
+    return strprintf("CBlockFileInfo(blocks=%u, size=%u, heights=%u...%u, time=%s...%s)", nBlocks, nSize, nHeightFirst, nHeightLast, DateTimeStrFormat("%Y-%m-%d", nTimeFirst), DateTimeStrFormat("%Y-%m-%d", nTimeLast));
 }
- std::string CBlockFileInfo::ToString() const {
-     return strprintf("CBlockFileInfo(blocks=%u, size=%u, heights=%u...%u, time=%s...%s)", nBlocks, nSize, nHeightFirst, nHeightLast, DateTimeStrFormat("%Y-%m-%d", nTimeFirst), DateTimeStrFormat("%Y-%m-%d", nTimeLast));
- }
 
 ThresholdState VersionBitsTipState(const Consensus::Params& params, Consensus::DeploymentPos pos)
 {
diff --git a/src/validation.h b/src/validation.h
index e50a82b9dd..f0f54786c7 100644
--- a/src/validation.h
+++ b/src/validation.h
@@ -137,7 +137,6 @@ static const bool DEFAULT_CHECKPOINTS_ENABLED = true;
 static const bool DEFAULT_TXINDEX = false;
 static const unsigned int DEFAULT_BANSCORE_THRESHOLD = 100;
 
-static const bool DEFAULT_TESTSAFEMODE = false;
 /** Default for -mempoolreplacement */
 static const bool DEFAULT_ENABLE_REPLACEMENT = true;
 /** Default for using fee filter */
diff --git a/src/warnings.cpp b/src/warnings.cpp
new file mode 100644
index 0000000000..2c1b1b0e12
--- /dev/null
+++ b/src/warnings.cpp
@@ -0,0 +1,89 @@
+// Copyright (c) 2009-2010 Satoshi Nakamoto
+// Copyright (c) 2009-2016 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#include "sync.h"
+#include "clientversion.h"
+#include "util.h"
+#include "warnings.h"
+
+CCriticalSection cs_warnings;
+std::string strMiscWarning;
+bool fLargeWorkForkFound = false;
+bool fLargeWorkInvalidChainFound = false;
+
+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)
+{
+    std::string strStatusBar;
+    std::string strRPC;
+    std::string strGUI;
+    const std::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");
+    }
+
+    if (GetBoolArg("-testsafemode", DEFAULT_TESTSAFEMODE))
+        strStatusBar = strRPC = strGUI = "testsafemode enabled";
+
+    // Misc warnings like out of disk space and clock is wrong
+    if (strMiscWarning != "")
+    {
+        strStatusBar = strMiscWarning;
+        strGUI += (strGUI.empty() ? "" : uiAlertSeperator) + strMiscWarning;
+    }
+
+    if (fLargeWorkForkFound)
+    {
+        strStatusBar = strRPC = "Warning: The network does not appear to fully agree! Some miners appear to be experiencing issues.";
+        strGUI += (strGUI.empty() ? "" : uiAlertSeperator) + _("Warning: The network does not appear to fully agree! Some miners appear to be experiencing issues.");
+    }
+    else if (fLargeWorkInvalidChainFound)
+    {
+        strStatusBar = strRPC = "Warning: We do not appear to fully agree with our peers! You may need to upgrade, or other nodes may need to upgrade.";
+        strGUI += (strGUI.empty() ? "" : uiAlertSeperator) + _("Warning: We do not appear to fully agree with our peers! You may need to upgrade, or other nodes may need to upgrade.");
+    }
+
+    if (strFor == "gui")
+        return strGUI;
+    else if (strFor == "statusbar")
+        return strStatusBar;
+    else if (strFor == "rpc")
+        return strRPC;
+    assert(!"GetWarnings(): invalid parameter");
+    return "error";
+}
diff --git a/src/warnings.h b/src/warnings.h
new file mode 100644
index 0000000000..a7aa657426
--- /dev/null
+++ b/src/warnings.h
@@ -0,0 +1,21 @@
+// Copyright (c) 2009-2010 Satoshi Nakamoto
+// Copyright (c) 2009-2016 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#ifndef BITCOIN_WARNINGS_H
+#define BITCOIN_WARNINGS_H
+
+#include <stdlib.h>
+#include <string>
+
+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);
+
+static const bool DEFAULT_TESTSAFEMODE = false;
+
+#endif //  BITCOIN_WARNINGS_H