Merge pull request #2224 from sipa/valstate

Improve error handling during validation

src/main.h

@@ -112,9 +112,11 @@ class CTxUndo;
 class CCoinsView;
 class CCoinsViewCache;
 class CScriptCheck;
+class CValidationState;
 
 struct CBlockTemplate;
 
+
 /** Register a wallet to receive updates from core */
 void RegisterWallet(CWallet* pwalletIn);
 /** Unregister a wallet from core */
@@ -122,7 +124,7 @@ void UnregisterWallet(CWallet* pwalletIn);
 /** Push an updated transaction to all registered wallets */
 void SyncWithWallets(const uint256 &hash, const CTransaction& tx, const CBlock* pblock = NULL, bool fUpdate = false);
 /** Process an incoming block */
-bool ProcessBlock(CNode* pfrom, CBlock* pblock, CDiskBlockPos *dbp = NULL);
+bool ProcessBlock(CValidationState &state, CNode* pfrom, CBlock* pblock, CDiskBlockPos *dbp = NULL);
 /** Check whether enough disk space is available for an incoming block */
 bool CheckDiskSpace(uint64 nAdditionalBytes = 0);
 /** Open a block file (blk?????.dat) */
@@ -172,13 +174,15 @@ std::string GetWarnings(std::string strFor);
 /** Retrieve a transaction (from memory pool, or from disk, if possible) */
 bool GetTransaction(const uint256 &hash, CTransaction &tx, uint256 &hashBlock, bool fAllowSlow = false);
 /** Connect/disconnect blocks until pindexNew is the new tip of the active block chain */
-bool SetBestChain(CBlockIndex* pindexNew);
+bool SetBestChain(CValidationState &state, CBlockIndex* pindexNew);
 /** Find the best known block, and make it the tip of the block chain */
-bool ConnectBestBlock();
+bool ConnectBestBlock(CValidationState &state);
 /** Create a new block index entry for a given block hash */
 CBlockIndex * InsertBlockIndex(uint256 hash);
 /** Verify a signature */
 bool VerifySignature(const CCoins& txFrom, const CTransaction& txTo, unsigned int nIn, unsigned int flags, int nHashType);
+/** Abort with a message */
+bool AbortNode(const std::string &msg);
 
 
 
@@ -454,7 +458,6 @@ public:
 
 
 
-
 enum GetMinFee_mode
 {
     GMF_BLOCK,
@@ -474,10 +477,6 @@ public:
     std::vector<CTxOut> vout;
     unsigned int nLockTime;
 
-    // Denial-of-service detection:
-    mutable int nDoS;
-    bool DoS(int nDoSIn, bool fIn) const { nDoS += nDoSIn; return fIn; }
-
     CTransaction()
     {
         SetNull();
@@ -498,7 +497,6 @@ public:
         vin.clear();
         vout.clear();
         nLockTime = 0;
-        nDoS = 0;  // Denial-of-service prevention
     }
 
     bool IsNull() const
@@ -654,27 +652,24 @@ public:
     }
 
 
-    // Do all possible client-mode checks
-    bool ClientCheckInputs() const;
-
     // Check whether all prevouts of this transaction are present in the UTXO set represented by view
     bool HaveInputs(CCoinsViewCache &view) const;
 
     // Check whether all inputs of this transaction are valid (no double spends, scripts & sigs, amounts)
     // This does not modify the UTXO set. If pvChecks is not NULL, script checks are pushed onto it
     // instead of being performed inline.
-    bool CheckInputs(CCoinsViewCache &view, bool fScriptChecks = true,
+    bool CheckInputs(CValidationState &state, CCoinsViewCache &view, bool fScriptChecks = true,
                      unsigned int flags = SCRIPT_VERIFY_P2SH | SCRIPT_VERIFY_STRICTENC,
                      std::vector<CScriptCheck> *pvChecks = NULL) const;
 
     // Apply the effects of this transaction on the UTXO set represented by view
-    bool UpdateCoins(CCoinsViewCache &view, CTxUndo &txundo, int nHeight, const uint256 &txhash) const;
+    bool UpdateCoins(CValidationState &state, CCoinsViewCache &view, CTxUndo &txundo, int nHeight, const uint256 &txhash) const;
 
     // Context-independent validity checks
-    bool CheckTransaction() const;
+    bool CheckTransaction(CValidationState &state) const;
 
     // Try to accept this transaction into the memory pool
-    bool AcceptToMemoryPool(bool fCheckInputs=true, bool fLimitFree = true, bool* pfMissingInputs=NULL);
+    bool AcceptToMemoryPool(CValidationState &state, bool fCheckInputs=true, bool fLimitFree = true, bool* pfMissingInputs=NULL);
 
 protected:
     static const CTxOut &GetOutputFor(const CTxIn& input, CCoinsViewCache& mapInputs);
@@ -1320,10 +1315,6 @@ public:
     // memory only
     mutable std::vector<uint256> vMerkleTree;
 
-    // Denial-of-service detection:
-    mutable int nDoS;
-    bool DoS(int nDoSIn, bool fIn) const { nDoS += nDoSIn; return fIn; }
-
     CBlock()
     {
         SetNull();
@@ -1346,7 +1337,6 @@ public:
         CBlockHeader::SetNull();
         vtx.clear();
         vMerkleTree.clear();
-        nDoS = 0;
     }
 
     CBlockHeader GetBlockHeader() const
@@ -1494,23 +1484,23 @@ public:
      *  In case pfClean is provided, operation will try to be tolerant about errors, and *pfClean
      *  will be true if no problems were found. Otherwise, the return value will be false in case
      *  of problems. Note that in any case, coins may be modified. */
-    bool DisconnectBlock(CBlockIndex *pindex, CCoinsViewCache &coins, bool *pfClean = NULL);
+    bool DisconnectBlock(CValidationState &state, CBlockIndex *pindex, CCoinsViewCache &coins, bool *pfClean = NULL);
 
     // Apply the effects of this block (with given index) on the UTXO set represented by coins
-    bool ConnectBlock(CBlockIndex *pindex, CCoinsViewCache &coins, bool fJustCheck=false);
+    bool ConnectBlock(CValidationState &state, CBlockIndex *pindex, CCoinsViewCache &coins, bool fJustCheck=false);
 
     // Read a block from disk
     bool ReadFromDisk(const CBlockIndex* pindex);
 
     // Add this block to the block index, and if necessary, switch the active block chain to this
-    bool AddToBlockIndex(const CDiskBlockPos &pos);
+    bool AddToBlockIndex(CValidationState &state, const CDiskBlockPos &pos);
 
     // Context-independent validity checks
-    bool CheckBlock(bool fCheckPOW=true, bool fCheckMerkleRoot=true) const;
+    bool CheckBlock(CValidationState &state, bool fCheckPOW=true, bool fCheckMerkleRoot=true) const;
 
     // Store block on disk
     // if dbp is provided, the file is known to already reside on disk
-    bool AcceptBlock(CDiskBlockPos *dbp = NULL);
+    bool AcceptBlock(CValidationState &state, CDiskBlockPos *dbp = NULL);
 };
 
 
@@ -1877,6 +1867,52 @@ public:
     }
 };
 
+/** Capture information about block/transaction validation */
+class CValidationState {
+private:
+    enum mode_state {
+        MODE_VALID,   // everything ok
+        MODE_INVALID, // network rule violation (DoS value may be set)
+        MODE_ERROR,   // run-time error
+    } mode;
+    int nDoS;
+public:
+    CValidationState() : mode(MODE_VALID), nDoS(0) {}
+    bool DoS(int level, bool ret = false) {
+        if (mode == MODE_ERROR)
+            return ret;
+        nDoS += level;
+        mode = MODE_INVALID;
+        return ret;
+    }
+    bool Invalid(bool ret = false) {
+        return DoS(0, ret);
+    }
+    bool Error() {
+        mode = MODE_ERROR;
+        return false;
+    }
+    bool Abort(const std::string &msg) {
+        AbortNode(msg);
+        return Error();
+    }
+    bool IsValid() {
+        return mode == MODE_VALID;
+    }
+    bool IsInvalid() {
+        return mode == MODE_INVALID;
+    }
+    bool IsError() {
+        return mode == MODE_ERROR;
+    }
+    bool IsInvalid(int &nDoSOut) {
+        if (IsInvalid()) {
+            nDoSOut = nDoS;
+            return true;
+        }
+        return false;
+    }
+};
 
 
 
@@ -2025,7 +2061,7 @@ public:
     std::map<uint256, CTransaction> mapTx;
     std::map<COutPoint, CInPoint> mapNextTx;
 
-    bool accept(CTransaction &tx, bool fCheckInputs, bool fLimitFree, bool* pfMissingInputs);
+    bool accept(CValidationState &state, CTransaction &tx, bool fCheckInputs, bool fLimitFree, bool* pfMissingInputs);
     bool addUnchecked(const uint256& hash, CTransaction &tx);
     bool remove(const CTransaction &tx, bool fRecursive = false);
     bool removeConflicts(const CTransaction &tx);