Report script evaluation failures in log and reject messages

Author: sipa

src/main.cpp

@@ -1327,7 +1327,7 @@ void static InvalidBlockFound(CBlockIndex *pindex, const CValidationState &state
     if (state.IsInvalid(nDoS)) {
         std::map<uint256, NodeId>::iterator it = mapBlockSource.find(pindex->GetBlockHash());
         if (it != mapBlockSource.end() && State(it->second)) {
-            CBlockReject reject = {state.GetRejectCode(), state.GetRejectReason(), pindex->GetBlockHash()};
+            CBlockReject reject = {state.GetRejectCode(), state.GetRejectReason().substr(0, MAX_REJECT_MESSAGE_LENGTH), pindex->GetBlockHash()};
             State(it->second)->rejects.push_back(reject);
             if (nDoS > 0)
                 Misbehaving(it->second, nDoS);
@@ -1357,10 +1357,11 @@ void UpdateCoins(const CTransaction& tx, CValidationState &state, CCoinsViewCach
     inputs.ModifyCoins(tx.GetHash())->FromTx(tx, nHeight);
 }
 
-bool CScriptCheck::operator()() const {
+bool CScriptCheck::operator()() {
     const CScript &scriptSig = ptxTo->vin[nIn].scriptSig;
-    if (!VerifyScript(scriptSig, scriptPubKey, nFlags, CachingSignatureChecker(*ptxTo, nIn, cacheStore)))
-        return error("CScriptCheck() : %s:%d VerifySignature failed", ptxTo->GetHash().ToString(), nIn);
+    if (!VerifyScript(scriptSig, scriptPubKey, nFlags, CachingSignatureChecker(*ptxTo, nIn, cacheStore), &error)) {
+        return ::error("CScriptCheck() : %s:%d VerifySignature failed: %s", ptxTo->GetHash().ToString(), nIn, ScriptErrorString(error));
+    }
     return true;
 }
 
@@ -1448,7 +1449,7 @@ bool CheckInputs(const CTransaction& tx, CValidationState &state, const CCoinsVi
                         CScriptCheck check(*coins, tx, i,
                                 flags & ~STANDARD_NOT_MANDATORY_VERIFY_FLAGS, cacheStore);
                         if (check())
-                            return state.Invalid(false, REJECT_NONSTANDARD, "non-mandatory-script-verify-flag");
+                            return state.Invalid(false, REJECT_NONSTANDARD, strprintf("non-mandatory-script-verify-flag (%s)", ScriptErrorString(check.GetScriptError())));
                     }
                     // Failures of other flags indicate a transaction that is
                     // invalid in new blocks, e.g. a invalid P2SH. We DoS ban
@@ -1457,7 +1458,7 @@ bool CheckInputs(const CTransaction& tx, CValidationState &state, const CCoinsVi
                     // as to the correct behavior - we may want to continue
                     // peering with non-upgraded nodes even after a soft-fork
                     // super-majority vote has passed.
-                    return state.DoS(100,false, REJECT_INVALID, "mandatory-script-verify-flag-failed");
+                    return state.DoS(100,false, REJECT_INVALID, strprintf("mandatory-script-verify-flag-failed (%s)", ScriptErrorString(check.GetScriptError())));
                 }
             }
         }
@@ -3975,7 +3976,7 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv,
                 pfrom->id, pfrom->cleanSubVer,
                 state.GetRejectReason());
             pfrom->PushMessage("reject", strCommand, state.GetRejectCode(),
-                               state.GetRejectReason(), inv.hash);
+                               state.GetRejectReason().substr(0, MAX_REJECT_MESSAGE_LENGTH), inv.hash);
             if (nDoS > 0)
                 Misbehaving(pfrom->GetId(), nDoS);
         }
@@ -4049,7 +4050,7 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv,
         int nDoS;
         if (state.IsInvalid(nDoS)) {
             pfrom->PushMessage("reject", strCommand, state.GetRejectCode(),
-                               state.GetRejectReason(), inv.hash);
+                               state.GetRejectReason().substr(0, MAX_REJECT_MESSAGE_LENGTH), inv.hash);
             if (nDoS > 0) {
                 LOCK(cs_main);
                 Misbehaving(pfrom->GetId(), nDoS);
@@ -4256,7 +4257,7 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv,
         if (fDebug) {
             try {
                 string strMsg; unsigned char ccode; string strReason;
-                vRecv >> LIMITED_STRING(strMsg, CMessageHeader::COMMAND_SIZE) >> ccode >> LIMITED_STRING(strReason, 111);
+                vRecv >> LIMITED_STRING(strMsg, CMessageHeader::COMMAND_SIZE) >> ccode >> LIMITED_STRING(strReason, MAX_REJECT_MESSAGE_LENGTH);
 
                 ostringstream ss;
                 ss << strMsg << " code " << itostr(ccode) << ": " << strReason;

src/main.h

@@ -96,6 +96,8 @@ static const unsigned int MAX_HEADERS_RESULTS = 2000;
 static const unsigned int BLOCK_DOWNLOAD_WINDOW = 1024;
 /** Time to wait (in seconds) between writing blockchain state to disk. */
 static const unsigned int DATABASE_WRITE_INTERVAL = 3600;
+/** Maximum length of reject messages. */
+static const unsigned int MAX_REJECT_MESSAGE_LENGTH = 111;
 
 /** "reject" message codes **/
 static const unsigned char REJECT_MALFORMED = 0x01;
@@ -325,22 +327,26 @@ class CScriptCheck
     unsigned int nIn;
     unsigned int nFlags;
     bool cacheStore;
+    ScriptError error;
 
 public:
-    CScriptCheck(): ptxTo(0), nIn(0), nFlags(0), cacheStore(false) {}
+    CScriptCheck(): ptxTo(0), nIn(0), nFlags(0), cacheStore(false), error(SCRIPT_ERR_UNKNOWN_ERROR) {}
     CScriptCheck(const CCoins& txFromIn, const CTransaction& txToIn, unsigned int nInIn, unsigned int nFlagsIn, bool cacheIn) :
         scriptPubKey(txFromIn.vout[txToIn.vin[nInIn].prevout.n].scriptPubKey),
-        ptxTo(&txToIn), nIn(nInIn), nFlags(nFlagsIn), cacheStore(cacheIn) { }
+        ptxTo(&txToIn), nIn(nInIn), nFlags(nFlagsIn), cacheStore(cacheIn), error(SCRIPT_ERR_UNKNOWN_ERROR) { }
 
-    bool operator()() const;
+    bool operator()();
 
     void swap(CScriptCheck &check) {
         scriptPubKey.swap(check.scriptPubKey);
         std::swap(ptxTo, check.ptxTo);
         std::swap(nIn, check.nIn);
         std::swap(nFlags, check.nFlags);
         std::swap(cacheStore, check.cacheStore);
+        std::swap(error, check.error);
     }
+
+    ScriptError GetScriptError() const { return error; }
 };
 
 /** Data structure that represents a partial merkle tree.