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-rw-r--r--src/init.cpp2
-rw-r--r--src/main.cpp94
2 files changed, 89 insertions, 7 deletions
diff --git a/src/init.cpp b/src/init.cpp
index 20d334019d..09871c012c 100644
--- a/src/init.cpp
+++ b/src/init.cpp
@@ -228,7 +228,7 @@ std::string HelpMessage()
strUsage += " -rpcthreads=<n> " + _("Set the number of threads to service RPC calls (default: 4)") + "\n";
strUsage += " -blocknotify=<cmd> " + _("Execute command when the best block changes (%s in cmd is replaced by block hash)") + "\n";
strUsage += " -walletnotify=<cmd> " + _("Execute command when a wallet transaction changes (%s in cmd is replaced by TxID)") + "\n";
- strUsage += " -alertnotify=<cmd> " + _("Execute command when a relevant alert is received (%s in cmd is replaced by message)") + "\n";
+ strUsage += " -alertnotify=<cmd> " + _("Execute command when a relevant alert is received or we see a really long fork (%s in cmd is replaced by message)") + "\n";
strUsage += " -upgradewallet " + _("Upgrade wallet to latest format") + "\n";
strUsage += " -keypool=<n> " + _("Set key pool size to <n> (default: 100)") + "\n";
strUsage += " -rescan " + _("Rescan the block chain for missing wallet transactions") + "\n";
diff --git a/src/main.cpp b/src/main.cpp
index 063536820d..e78e055147 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -1376,6 +1376,82 @@ bool IsInitialBlockDownload()
pindexBest->GetBlockTime() < GetTime() - 24 * 60 * 60);
}
+bool fLargeWorkForkFound = false;
+bool fLargeWorkInvalidChainFound = false;
+CBlockIndex *pindexBestForkTip = NULL, *pindexBestForkBase = NULL;
+
+void CheckForkWarningConditions()
+{
+ // If our best fork is no longer within 72 blocks (+/- 12 hours if no one mines it)
+ // of our head, drop it
+ if (pindexBestForkTip && nBestHeight - pindexBestForkTip->nHeight >= 72)
+ pindexBestForkTip = NULL;
+
+ if (pindexBestForkTip || nBestInvalidWork > nBestChainWork + (pindexBest->GetBlockWork() * 6).getuint256())
+ {
+ if (!fLargeWorkForkFound)
+ {
+ std::string strCmd = GetArg("-alertnotify", "");
+ if (!strCmd.empty())
+ {
+ std::string warning = std::string("'Warning: Large-work fork detected, forking after block ") +
+ pindexBestForkBase->phashBlock->ToString() + std::string("'");
+ boost::replace_all(strCmd, "%s", warning);
+ boost::thread t(runCommand, strCmd); // thread runs free
+ }
+ }
+ if (pindexBestForkTip)
+ {
+ printf("CheckForkWarningConditions: 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",
+ pindexBestForkBase->nHeight, pindexBestForkBase->phashBlock->ToString().c_str(),
+ pindexBestForkTip->nHeight, pindexBestForkTip->phashBlock->ToString().c_str());
+ fLargeWorkForkFound = true;
+ }
+ else
+ {
+ printf("CheckForkWarningConditions: Warning: Found invalid chain at least ~6 blocks longer than our best chain.\nChain state database corruption likely.\n");
+ fLargeWorkInvalidChainFound = true;
+ }
+ }
+ else
+ {
+ fLargeWorkForkFound = false;
+ fLargeWorkInvalidChainFound = false;
+ }
+}
+
+void CheckForkWarningConditionsOnNewFork(CBlockIndex* pindexNewForkTip)
+{
+ // If we are on a fork that is sufficiently large, set a warning flag
+ CBlockIndex* pfork = pindexNewForkTip;
+ CBlockIndex* plonger = pindexBest;
+ while (pfork && pfork != plonger)
+ {
+ while (plonger && plonger->nHeight > pfork->nHeight)
+ plonger = plonger->pprev;
+ if (pfork == plonger)
+ break;
+ pfork = pfork->pprev;
+ }
+
+ // We define a condition which we should warn the user about as a fork of at least 7 blocks
+ // who's tip is within 72 blocks (+/- 12 hours if no one mines it) of ours
+ // We use 7 blocks rather arbitrarily as it represents just under 10% of sustained network
+ // hash rate operating on the fork.
+ // or a chain that is entirely longer than ours and invalid (note that this should be detected by both)
+ // We define it this way because it allows us to only store the highest fork tip (+ base) which meets
+ // the 7-block condition and from this always have the most-likely-to-cause-warning fork
+ if (pfork && (!pindexBestForkTip || (pindexBestForkTip && pindexNewForkTip->nHeight > pindexBestForkTip->nHeight)) &&
+ pindexNewForkTip->nChainWork - pfork->nChainWork > (pfork->GetBlockWork() * 7).getuint256() &&
+ nBestHeight - pindexNewForkTip->nHeight < 72)
+ {
+ pindexBestForkTip = pindexNewForkTip;
+ pindexBestForkBase = pfork;
+ }
+
+ CheckForkWarningConditions();
+}
+
void static InvalidChainFound(CBlockIndex* pindexNew)
{
if (pindexNew->nChainWork > nBestInvalidWork)
@@ -1391,8 +1467,7 @@ void static InvalidChainFound(CBlockIndex* pindexNew)
printf("InvalidChainFound: current best=%s height=%d log2_work=%.8g date=%s\n",
hashBestChain.ToString().c_str(), nBestHeight, log(nBestChainWork.getdouble())/log(2.0),
DateTimeStrFormat("%Y-%m-%d %H:%M:%S", pindexBest->GetBlockTime()).c_str());
- if (pindexBest && nBestInvalidWork > nBestChainWork + (pindexBest->GetBlockWork() * 6).getuint256())
- printf("InvalidChainFound: Warning: Displayed transactions may not be correct! You may need to upgrade, or other nodes may need to upgrade.\n");
+ CheckForkWarningConditions();
}
void static InvalidBlockFound(CBlockIndex *pindex) {
@@ -2103,11 +2178,14 @@ bool AddToBlockIndex(CBlock& block, CValidationState& state, const CDiskBlockPos
if (pindexNew == pindexBest)
{
+ // Clear fork warning if its no longer applicable
+ CheckForkWarningConditions();
// Notify UI to display prev block's coinbase if it was ours
static uint256 hashPrevBestCoinBase;
UpdatedTransaction(hashPrevBestCoinBase);
hashPrevBestCoinBase = block.GetTxHash(0);
- }
+ } else
+ CheckForkWarningConditionsOnNewFork(pindexNew);
if (!pblocktree->Flush())
return state.Abort(_("Failed to sync block index"));
@@ -3066,11 +3144,15 @@ string GetWarnings(string strFor)
strStatusBar = strMiscWarning;
}
- // Longer invalid proof-of-work chain
- if (pindexBest && nBestInvalidWork > nBestChainWork + (pindexBest->GetBlockWork() * 6).getuint256())
+ if (fLargeWorkForkFound)
+ {
+ nPriority = 2000;
+ strStatusBar = strRPC = _("Warning: The network does not appear to fully agree! Some miners appear to be experiencing issues.");
+ }
+ else if (fLargeWorkInvalidChainFound)
{
nPriority = 2000;
- strStatusBar = strRPC = _("Warning: Displayed transactions may not be correct! You may need to upgrade, or other nodes may need to upgrade.");
+ 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.");
}
// Alerts