Function SignPSBTInput

src/script/sign.cpp:242–295

}

bool SignPSBTInput(const SigningProvider& provider, PartiallySignedTransaction& psbt, SignatureData& sigdata, int index, bool no_forkid, int sighash)
{
    PSBTInput& input = psbt.inputs.at(index);
    const CMutableTransaction& tx = *psbt.tx;

    if (PSBTInputSigned(input)) {
        return true;
    }

    // Fill SignatureData with input info
    input.FillSignatureData(sigdata);

    // Get UTXO
    bool require_witness_sig = false;
    CTxOut utxo;

    // Verify input sanity, which checks that at most one of witness or non-witness utxos is provided.
    if (!input.IsSane()) {
        return false;
    }

    if (input.non_witness_utxo) {
        // If we're taking our information from a non-witness UTXO, verify that it matches the prevout.
        COutPoint prevout = tx.vin[index].prevout;
        if (input.non_witness_utxo->GetHash() != prevout.hash) {
            return false;
        }
        utxo = input.non_witness_utxo->vout[prevout.n];
    } else if (!input.witness_utxo.IsNull()) {
        utxo = input.witness_utxo;
        // When we're taking our information from a witness UTXO, we can't verify it is actually data from
        // the output being spent. This is safe in case a witness signature is produced (which includes this
        // information directly in the hash), but not for non-witness signatures. Remember that we require
        // a witness signature in this situation.
        require_witness_sig = true;
    } else {
        return false;
    }

    MutableTransactionSignatureCreator creator(&tx, index, utxo.nValue, no_forkid, sighash);
    sigdata.witness = false;
    bool sig_complete = ProduceSignature(provider, creator, utxo.scriptPubKey, sigdata, no_forkid);
    // Verify that a witness signature was produced in case one was required.
    if (require_witness_sig && !sigdata.witness) return false;
    input.FromSignatureData(sigdata);

    // If we have a witness signature, use the smaller witness UTXO.
    if (sigdata.witness) {
        input.witness_utxo = utxo;
        input.non_witness_utxo = nullptr;
    }

    return sig_complete;
}

class SignatureExtractorChecker final : public BaseSignatureChecker
{