1// Copyright (c) 2020-present The Bitcoin Core developers
2// Distributed under the MIT software license, see the accompanying
3// file COPYING or http://www.opensource.org/licenses/mit-license.php.
4
5#include <chainparams.h>
6#include <common/args.h>
7#include <common/system.h>
8#include <external_signer.h>
9#include <node/types.h>
10#include <wallet/external_signer_scriptpubkeyman.h>
11
12#include <iostream>
13#include <key_io.h>
14#include <memory>
15#include <stdexcept>
16#include <string>
17#include <univalue.h>
18#include <utility>
19#include <vector>
20
21using common::PSBTError;
22
23namespace wallet {
24std::unique_ptr<ExternalSignerScriptPubKeyMan> ExternalSignerScriptPubKeyMan::LoadFromStorage(WalletStorage& storage, const uint256& id, WalletDescriptor& descriptor, int64_t keypool_size, const KeyMap& keys, const CryptedKeyMap& ckeys)
25{
26    return std::unique_ptr<ExternalSignerScriptPubKeyMan>(new ExternalSignerScriptPubKeyMan(storage, id, descriptor, keypool_size, keys, ckeys));
27}
28
29std::unique_ptr<ExternalSignerScriptPubKeyMan> ExternalSignerScriptPubKeyMan::CreateNew(WalletStorage& storage, WalletBatch& batch, int64_t keypool_size, std::unique_ptr<Descriptor> desc)
30{
31    int64_t creation_time = GetTime();
32
33    // Make the descriptor
34    WalletDescriptor w_desc(std::move(desc), creation_time, 0, 0, 0);
35
36    auto spkm = std::unique_ptr<ExternalSignerScriptPubKeyMan>(new ExternalSignerScriptPubKeyMan(storage, w_desc, keypool_size));
37
38    LOCK(spkm->cs_desc_man);
39    assert(storage.IsWalletFlagSet(WALLET_FLAG_DESCRIPTORS));
40    assert(storage.IsWalletFlagSet(WALLET_FLAG_EXTERNAL_SIGNER));
41
42    // Store the descriptor
43    if (!batch.WriteDescriptor(spkm->GetID(), spkm->m_wallet_descriptor)) {
44        throw std::runtime_error(std::string(__func__) + ": writing descriptor failed");
45    }
46
47    // TopUp
48    spkm->TopUpWithDB(batch);
49
50    storage.UnsetBlankWalletFlag(batch);
51    return spkm;
52}
53
54 util::Result<ExternalSigner> ExternalSignerScriptPubKeyMan::GetExternalSigner() {
55    const std::string command = gArgs.GetArg("-signer", "");
56    if (command == "") return util::Error{Untranslated("restart bitcoind with -signer=<cmd>")};
57    std::vector<ExternalSigner> signers;
58    ExternalSigner::Enumerate(command, signers, Params().GetChainTypeString());
59    if (signers.empty()) return util::Error{Untranslated("No external signers found")};
60    // TODO: add fingerprint argument instead of failing in case of multiple signers.
61    if (signers.size() > 1) return util::Error{Untranslated("More than one external signer found. Please connect only one at a time.")};
62    return signers[0];
63}
64
65util::Result<void> ExternalSignerScriptPubKeyMan::DisplayAddress(const CTxDestination& dest, const ExternalSigner &signer) const
66{
67    // TODO: avoid the need to infer a descriptor from inside a descriptor wallet
68    const CScript& scriptPubKey = GetScriptForDestination(dest);
69    auto provider = GetSolvingProvider(scriptPubKey);
70    auto descriptor = InferDescriptor(scriptPubKey, *provider);
71
72    const UniValue& result = signer.DisplayAddress(descriptor->ToString());
73
74    const UniValue& error = result.find_value("error");
75    if (error.isStr()) return util::Error{strprintf(_("Signer returned error: %s"), error.getValStr())};
76
77    const UniValue& ret_address = result.find_value("address");
78    if (!ret_address.isStr()) return util::Error{_("Signer did not echo address")};
79
80    if (ret_address.getValStr() != EncodeDestination(dest)) {
81        return util::Error{strprintf(_("Signer echoed unexpected address %s"), ret_address.getValStr())};
82    }
83
84    return util::Result<void>();
85}
86
87// If sign is true, transaction must previously have been filled
88std::optional<PSBTError> ExternalSignerScriptPubKeyMan::FillPSBT(PartiallySignedTransaction& psbt, const PrecomputedTransactionData& txdata, const common::PSBTFillOptions& options, int* n_signed) const
89{
90    if (!options.sign) {
91        return DescriptorScriptPubKeyMan::FillPSBT(psbt, txdata, options, n_signed);
92    }
93
94    // Already complete if every input is now signed
95    bool complete = true;
96    for (const auto& input : psbt.inputs) {
97        complete &= PSBTInputSigned(input);
98    }
99    if (complete) return {};
100
101    auto signer{GetExternalSigner()};
102    if (!signer) {
103        LogWarning("%s", util::ErrorString(signer).original);
104        return PSBTError::EXTERNAL_SIGNER_NOT_FOUND;
105    }
106
107    std::string failure_reason;
108    if(!signer->SignTransaction(psbt, failure_reason)) {
109        LogWarning("Failed to sign: %s\n", failure_reason);
110        return PSBTError::EXTERNAL_SIGNER_FAILED;
111    }
112    if (options.finalize) FinalizePSBT(psbt); // This won't work in a multisig setup
113    return {};
114}
115} // namespace wallet
116