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// Copyright (c) 2010 Satoshi Nakamoto
// Copyright (c) 2009-2022 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 <chain.h>
#include <chainparams.h>
#include <coins.h>
#include <index/txindex.h>
#include <merkleblock.h>
#include <node/blockstorage.h>
#include <primitives/transaction.h>
#include <rpc/server.h>
#include <rpc/server_util.h>
#include <rpc/util.h>
#include <univalue.h>
#include <util/strencodings.h>
#include <validation.h>
using node::GetTransaction;
using node::ReadBlockFromDisk;
static RPCHelpMan gettxoutproof()
{
return RPCHelpMan{"gettxoutproof",
"\nReturns a hex-encoded proof that \"txid\" was included in a block.\n"
"\nNOTE: By default this function only works sometimes. This is when there is an\n"
"unspent output in the utxo for this transaction. To make it always work,\n"
"you need to maintain a transaction index, using the -txindex command line option or\n"
"specify the block in which the transaction is included manually (by blockhash).\n",
{
{"txids", RPCArg::Type::ARR, RPCArg::Optional::NO, "The txids to filter",
{
{"txid", RPCArg::Type::STR_HEX, RPCArg::Optional::OMITTED, "A transaction hash"},
},
},
{"blockhash", RPCArg::Type::STR_HEX, RPCArg::Optional::OMITTED, "If specified, looks for txid in the block with this hash"},
},
RPCResult{
RPCResult::Type::STR, "data", "A string that is a serialized, hex-encoded data for the proof."
},
RPCExamples{""},
[&](const RPCHelpMan& self, const JSONRPCRequest& request) -> UniValue
{
std::set<uint256> setTxids;
UniValue txids = request.params[0].get_array();
if (txids.empty()) {
throw JSONRPCError(RPC_INVALID_PARAMETER, "Parameter 'txids' cannot be empty");
}
for (unsigned int idx = 0; idx < txids.size(); idx++) {
auto ret = setTxids.insert(ParseHashV(txids[idx], "txid"));
if (!ret.second) {
throw JSONRPCError(RPC_INVALID_PARAMETER, std::string("Invalid parameter, duplicated txid: ") + txids[idx].get_str());
}
}
const CBlockIndex* pblockindex = nullptr;
uint256 hashBlock;
ChainstateManager& chainman = EnsureAnyChainman(request.context);
if (!request.params[1].isNull()) {
LOCK(cs_main);
hashBlock = ParseHashV(request.params[1], "blockhash");
pblockindex = chainman.m_blockman.LookupBlockIndex(hashBlock);
if (!pblockindex) {
throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Block not found");
}
} else {
LOCK(cs_main);
Chainstate& active_chainstate = chainman.ActiveChainstate();
// Loop through txids and try to find which block they're in. Exit loop once a block is found.
for (const auto& tx : setTxids) {
const Coin& coin = AccessByTxid(active_chainstate.CoinsTip(), tx);
if (!coin.IsSpent()) {
pblockindex = active_chainstate.m_chain[coin.nHeight];
break;
}
}
}
// Allow txindex to catch up if we need to query it and before we acquire cs_main.
if (g_txindex && !pblockindex) {
g_txindex->BlockUntilSyncedToCurrentChain();
}
if (pblockindex == nullptr) {
const CTransactionRef tx = GetTransaction(/*block_index=*/nullptr, /*mempool=*/nullptr, *setTxids.begin(), chainman.GetConsensus(), hashBlock);
if (!tx || hashBlock.IsNull()) {
throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Transaction not yet in block");
}
LOCK(cs_main);
pblockindex = chainman.m_blockman.LookupBlockIndex(hashBlock);
if (!pblockindex) {
throw JSONRPCError(RPC_INTERNAL_ERROR, "Transaction index corrupt");
}
}
CBlock block;
if (!ReadBlockFromDisk(block, pblockindex, chainman.GetConsensus())) {
throw JSONRPCError(RPC_INTERNAL_ERROR, "Can't read block from disk");
}
unsigned int ntxFound = 0;
for (const auto& tx : block.vtx) {
if (setTxids.count(tx->GetHash())) {
ntxFound++;
}
}
if (ntxFound != setTxids.size()) {
throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Not all transactions found in specified or retrieved block");
}
DataStream ssMB{};
CMerkleBlock mb(block, setTxids);
ssMB << mb;
std::string strHex = HexStr(ssMB);
return strHex;
},
};
}
static RPCHelpMan verifytxoutproof()
{
return RPCHelpMan{"verifytxoutproof",
"\nVerifies that a proof points to a transaction in a block, returning the transaction it commits to\n"
"and throwing an RPC error if the block is not in our best chain\n",
{
{"proof", RPCArg::Type::STR_HEX, RPCArg::Optional::NO, "The hex-encoded proof generated by gettxoutproof"},
},
RPCResult{
RPCResult::Type::ARR, "", "",
{
{RPCResult::Type::STR_HEX, "txid", "The txid(s) which the proof commits to, or empty array if the proof cannot be validated."},
}
},
RPCExamples{""},
[&](const RPCHelpMan& self, const JSONRPCRequest& request) -> UniValue
{
DataStream ssMB{ParseHexV(request.params[0], "proof")};
CMerkleBlock merkleBlock;
ssMB >> merkleBlock;
UniValue res(UniValue::VARR);
std::vector<uint256> vMatch;
std::vector<unsigned int> vIndex;
if (merkleBlock.txn.ExtractMatches(vMatch, vIndex) != merkleBlock.header.hashMerkleRoot)
return res;
ChainstateManager& chainman = EnsureAnyChainman(request.context);
LOCK(cs_main);
const CBlockIndex* pindex = chainman.m_blockman.LookupBlockIndex(merkleBlock.header.GetHash());
if (!pindex || !chainman.ActiveChain().Contains(pindex) || pindex->nTx == 0) {
throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Block not found in chain");
}
// Check if proof is valid, only add results if so
if (pindex->nTx == merkleBlock.txn.GetNumTransactions()) {
for (const uint256& hash : vMatch) {
res.push_back(hash.GetHex());
}
}
return res;
},
};
}
void RegisterTxoutProofRPCCommands(CRPCTable& t)
{
static const CRPCCommand commands[]{
{"blockchain", &gettxoutproof},
{"blockchain", &verifytxoutproof},
};
for (const auto& c : commands) {
t.appendCommand(c.name, &c);
}
}
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