[build] Move rpc rawtransaction util functions to rpc/rawtransaction_util.cpp

rpc/rawtransaction.cpp moves to libbitcoin_server since it should not be
accessed by non-node libraries. The utility following utility methods
move to their own unit rpc/rawtransaction_util since they need to be
accessed by non-node libraries:

- `ConstructTransaction`
- `TxInErrorToJSON`
- `SignTransaction`

1 files changed, 293 insertions, 0 deletions

diff --git a/src/rpc/rawtransaction_util.cpp b/src/rpc/rawtransaction_util.cpp
new file mode 100644
index 0000000000..8b2ab8fa91
--- /dev/null
+++ b/src/rpc/rawtransaction_util.cpp
@@ -0,0 +1,293 @@
+// Copyright (c) 2010 Satoshi Nakamoto
+// Copyright (c) 2009-2019 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 <rpc/rawtransaction_util.h>
+
+#include <coins.h>
+#include <core_io.h>
+#include <interfaces/chain.h>
+#include <key_io.h>
+#include <keystore.h>
+#include <policy/policy.h>
+#include <policy/rbf.h>
+#include <primitives/transaction.h>
+#include <rpc/protocol.h>
+#include <rpc/util.h>
+#include <tinyformat.h>
+#include <univalue.h>
+#include <util/strencodings.h>
+
+CMutableTransaction ConstructTransaction(const UniValue& inputs_in, const UniValue& outputs_in, const UniValue& locktime, const UniValue& rbf)
+{
+    if (inputs_in.isNull() || outputs_in.isNull())
+        throw JSONRPCError(RPC_INVALID_PARAMETER, "Invalid parameter, arguments 1 and 2 must be non-null");
+
+    UniValue inputs = inputs_in.get_array();
+    const bool outputs_is_obj = outputs_in.isObject();
+    UniValue outputs = outputs_is_obj ? outputs_in.get_obj() : outputs_in.get_array();
+
+    CMutableTransaction rawTx;
+
+    if (!locktime.isNull()) {
+        int64_t nLockTime = locktime.get_int64();
+        if (nLockTime < 0 || nLockTime > LOCKTIME_MAX)
+            throw JSONRPCError(RPC_INVALID_PARAMETER, "Invalid parameter, locktime out of range");
+        rawTx.nLockTime = nLockTime;
+    }
+
+    bool rbfOptIn = rbf.isTrue();
+
+    for (unsigned int idx = 0; idx < inputs.size(); idx++) {
+        const UniValue& input = inputs[idx];
+        const UniValue& o = input.get_obj();
+
+        uint256 txid = ParseHashO(o, "txid");
+
+        const UniValue& vout_v = find_value(o, "vout");
+        if (!vout_v.isNum())
+            throw JSONRPCError(RPC_INVALID_PARAMETER, "Invalid parameter, missing vout key");
+        int nOutput = vout_v.get_int();
+        if (nOutput < 0)
+            throw JSONRPCError(RPC_INVALID_PARAMETER, "Invalid parameter, vout must be positive");
+
+        uint32_t nSequence;
+        if (rbfOptIn) {
+            nSequence = MAX_BIP125_RBF_SEQUENCE; /* CTxIn::SEQUENCE_FINAL - 2 */
+        } else if (rawTx.nLockTime) {
+            nSequence = CTxIn::SEQUENCE_FINAL - 1;
+        } else {
+            nSequence = CTxIn::SEQUENCE_FINAL;
+        }
+
+        // set the sequence number if passed in the parameters object
+        const UniValue& sequenceObj = find_value(o, "sequence");
+        if (sequenceObj.isNum()) {
+            int64_t seqNr64 = sequenceObj.get_int64();
+            if (seqNr64 < 0 || seqNr64 > CTxIn::SEQUENCE_FINAL) {
+                throw JSONRPCError(RPC_INVALID_PARAMETER, "Invalid parameter, sequence number is out of range");
+            } else {
+                nSequence = (uint32_t)seqNr64;
+            }
+        }
+
+        CTxIn in(COutPoint(txid, nOutput), CScript(), nSequence);
+
+        rawTx.vin.push_back(in);
+    }
+
+    if (!outputs_is_obj) {
+        // Translate array of key-value pairs into dict
+        UniValue outputs_dict = UniValue(UniValue::VOBJ);
+        for (size_t i = 0; i < outputs.size(); ++i) {
+            const UniValue& output = outputs[i];
+            if (!output.isObject()) {
+                throw JSONRPCError(RPC_INVALID_PARAMETER, "Invalid parameter, key-value pair not an object as expected");
+            }
+            if (output.size() != 1) {
+                throw JSONRPCError(RPC_INVALID_PARAMETER, "Invalid parameter, key-value pair must contain exactly one key");
+            }
+            outputs_dict.pushKVs(output);
+        }
+        outputs = std::move(outputs_dict);
+    }
+
+    // Duplicate checking
+    std::set<CTxDestination> destinations;
+    bool has_data{false};
+
+    for (const std::string& name_ : outputs.getKeys()) {
+        if (name_ == "data") {
+            if (has_data) {
+                throw JSONRPCError(RPC_INVALID_PARAMETER, "Invalid parameter, duplicate key: data");
+            }
+            has_data = true;
+            std::vector<unsigned char> data = ParseHexV(outputs[name_].getValStr(), "Data");
+
+            CTxOut out(0, CScript() << OP_RETURN << data);
+            rawTx.vout.push_back(out);
+        } else {
+            CTxDestination destination = DecodeDestination(name_);
+            if (!IsValidDestination(destination)) {
+                throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, std::string("Invalid Bitcoin address: ") + name_);
+            }
+
+            if (!destinations.insert(destination).second) {
+                throw JSONRPCError(RPC_INVALID_PARAMETER, std::string("Invalid parameter, duplicated address: ") + name_);
+            }
+
+            CScript scriptPubKey = GetScriptForDestination(destination);
+            CAmount nAmount = AmountFromValue(outputs[name_]);
+
+            CTxOut out(nAmount, scriptPubKey);
+            rawTx.vout.push_back(out);
+        }
+    }
+
+    if (!rbf.isNull() && rawTx.vin.size() > 0 && rbfOptIn != SignalsOptInRBF(CTransaction(rawTx))) {
+        throw JSONRPCError(RPC_INVALID_PARAMETER, "Invalid parameter combination: Sequence number(s) contradict replaceable option");
+    }
+
+    return rawTx;
+}
+
+/** Pushes a JSON object for script verification or signing errors to vErrorsRet. */
+static void TxInErrorToJSON(const CTxIn& txin, UniValue& vErrorsRet, const std::string& strMessage)
+{
+    UniValue entry(UniValue::VOBJ);
+    entry.pushKV("txid", txin.prevout.hash.ToString());
+    entry.pushKV("vout", (uint64_t)txin.prevout.n);
+    UniValue witness(UniValue::VARR);
+    for (unsigned int i = 0; i < txin.scriptWitness.stack.size(); i++) {
+        witness.push_back(HexStr(txin.scriptWitness.stack[i].begin(), txin.scriptWitness.stack[i].end()));
+    }
+    entry.pushKV("witness", witness);
+    entry.pushKV("scriptSig", HexStr(txin.scriptSig.begin(), txin.scriptSig.end()));
+    entry.pushKV("sequence", (uint64_t)txin.nSequence);
+    entry.pushKV("error", strMessage);
+    vErrorsRet.push_back(entry);
+}
+
+// TODO(https://github.com/bitcoin/bitcoin/pull/10973#discussion_r267084237):
+// The dependency on interfaces::Chain should be removed, so
+// signrawtransactionwithkey doesn't need access to a Chain instance.
+UniValue SignTransaction(interfaces::Chain& chain, CMutableTransaction& mtx, const UniValue& prevTxsUnival, CBasicKeyStore *keystore, bool is_temp_keystore, const UniValue& hashType)
+{
+    // Fetch previous transactions (inputs):
+    std::map<COutPoint, Coin> coins;
+    for (const CTxIn& txin : mtx.vin) {
+        coins[txin.prevout]; // Create empty map entry keyed by prevout.
+    }
+    chain.findCoins(coins);
+
+    // Add previous txouts given in the RPC call:
+    if (!prevTxsUnival.isNull()) {
+        UniValue prevTxs = prevTxsUnival.get_array();
+        for (unsigned int idx = 0; idx < prevTxs.size(); ++idx) {
+            const UniValue& p = prevTxs[idx];
+            if (!p.isObject()) {
+                throw JSONRPCError(RPC_DESERIALIZATION_ERROR, "expected object with {\"txid'\",\"vout\",\"scriptPubKey\"}");
+            }
+
+            UniValue prevOut = p.get_obj();
+
+            RPCTypeCheckObj(prevOut,
+                {
+                    {"txid", UniValueType(UniValue::VSTR)},
+                    {"vout", UniValueType(UniValue::VNUM)},
+                    {"scriptPubKey", UniValueType(UniValue::VSTR)},
+                });
+
+            uint256 txid = ParseHashO(prevOut, "txid");
+
+            int nOut = find_value(prevOut, "vout").get_int();
+            if (nOut < 0) {
+                throw JSONRPCError(RPC_DESERIALIZATION_ERROR, "vout must be positive");
+            }
+
+            COutPoint out(txid, nOut);
+            std::vector<unsigned char> pkData(ParseHexO(prevOut, "scriptPubKey"));
+            CScript scriptPubKey(pkData.begin(), pkData.end());
+
+            {
+                auto coin = coins.find(out);
+                if (coin != coins.end() && !coin->second.IsSpent() && coin->second.out.scriptPubKey != scriptPubKey) {
+                    std::string err("Previous output scriptPubKey mismatch:\n");
+                    err = err + ScriptToAsmStr(coin->second.out.scriptPubKey) + "\nvs:\n"+
+                        ScriptToAsmStr(scriptPubKey);
+                    throw JSONRPCError(RPC_DESERIALIZATION_ERROR, err);
+                }
+                Coin newcoin;
+                newcoin.out.scriptPubKey = scriptPubKey;
+                newcoin.out.nValue = MAX_MONEY;
+                if (prevOut.exists("amount")) {
+                    newcoin.out.nValue = AmountFromValue(find_value(prevOut, "amount"));
+                }
+                newcoin.nHeight = 1;
+                coins[out] = std::move(newcoin);
+            }
+
+            // if redeemScript and private keys were given, add redeemScript to the keystore so it can be signed
+            if (is_temp_keystore && (scriptPubKey.IsPayToScriptHash() || scriptPubKey.IsPayToWitnessScriptHash())) {
+                RPCTypeCheckObj(prevOut,
+                    {
+                        {"redeemScript", UniValueType(UniValue::VSTR)},
+                        {"witnessScript", UniValueType(UniValue::VSTR)},
+                    }, true);
+                UniValue rs = find_value(prevOut, "redeemScript");
+                if (!rs.isNull()) {
+                    std::vector<unsigned char> rsData(ParseHexV(rs, "redeemScript"));
+                    CScript redeemScript(rsData.begin(), rsData.end());
+                    keystore->AddCScript(redeemScript);
+                    // Automatically also add the P2WSH wrapped version of the script (to deal with P2SH-P2WSH).
+                    // This is only for compatibility, it is encouraged to use the explicit witnessScript field instead.
+                    keystore->AddCScript(GetScriptForWitness(redeemScript));
+                }
+                UniValue ws = find_value(prevOut, "witnessScript");
+                if (!ws.isNull()) {
+                    std::vector<unsigned char> wsData(ParseHexV(ws, "witnessScript"));
+                    CScript witnessScript(wsData.begin(), wsData.end());
+                    keystore->AddCScript(witnessScript);
+                    // Automatically also add the P2WSH wrapped version of the script (to deal with P2SH-P2WSH).
+                    keystore->AddCScript(GetScriptForWitness(witnessScript));
+                }
+            }
+        }
+    }
+
+    int nHashType = ParseSighashString(hashType);
+
+    bool fHashSingle = ((nHashType & ~SIGHASH_ANYONECANPAY) == SIGHASH_SINGLE);
+
+    // Script verification errors
+    UniValue vErrors(UniValue::VARR);
+
+    // Use CTransaction for the constant parts of the
+    // transaction to avoid rehashing.
+    const CTransaction txConst(mtx);
+    // Sign what we can:
+    for (unsigned int i = 0; i < mtx.vin.size(); i++) {
+        CTxIn& txin = mtx.vin[i];
+        auto coin = coins.find(txin.prevout);
+        if (coin == coins.end() || coin->second.IsSpent()) {
+            TxInErrorToJSON(txin, vErrors, "Input not found or already spent");
+            continue;
+        }
+        const CScript& prevPubKey = coin->second.out.scriptPubKey;
+        const CAmount& amount = coin->second.out.nValue;
+
+        SignatureData sigdata = DataFromTransaction(mtx, i, coin->second.out);
+        // Only sign SIGHASH_SINGLE if there's a corresponding output:
+        if (!fHashSingle || (i < mtx.vout.size())) {
+            ProduceSignature(*keystore, MutableTransactionSignatureCreator(&mtx, i, amount, nHashType), prevPubKey, sigdata);
+        }
+
+        UpdateInput(txin, sigdata);
+
+        // amount must be specified for valid segwit signature
+        if (amount == MAX_MONEY && !txin.scriptWitness.IsNull()) {
+            throw JSONRPCError(RPC_TYPE_ERROR, strprintf("Missing amount for %s", coin->second.out.ToString()));
+        }
+
+        ScriptError serror = SCRIPT_ERR_OK;
+        if (!VerifyScript(txin.scriptSig, prevPubKey, &txin.scriptWitness, STANDARD_SCRIPT_VERIFY_FLAGS, TransactionSignatureChecker(&txConst, i, amount), &serror)) {
+            if (serror == SCRIPT_ERR_INVALID_STACK_OPERATION) {
+                // Unable to sign input and verification failed (possible attempt to partially sign).
+                TxInErrorToJSON(txin, vErrors, "Unable to sign input, invalid stack size (possibly missing key)");
+            } else {
+                TxInErrorToJSON(txin, vErrors, ScriptErrorString(serror));
+            }
+        }
+    }
+    bool fComplete = vErrors.empty();
+
+    UniValue result(UniValue::VOBJ);
+    result.pushKV("hex", EncodeHexTx(CTransaction(mtx)));
+    result.pushKV("complete", fComplete);
+    if (!vErrors.empty()) {
+        result.pushKV("errors", vErrors);
+    }
+
+    return result;
+}