Function sign_last_tx

lightningd/peer_control.c:220–253

}

static void sign_last_tx(struct channel *channel,
			 struct bitcoin_tx *last_tx,
			 struct bitcoin_signature *last_sig)
{
	struct lightningd *ld = channel->peer->ld;
	struct bitcoin_signature sig;
	u8 *msg, **witness;

	u64 commit_index = channel->next_index[LOCAL] - 1;

	assert(!last_tx->wtx->inputs[0].witness);
	msg = towire_hsmd_sign_commitment_tx(tmpctx,
					     &channel->peer->id,
					     channel->dbid,
					     last_tx,
					     &channel->channel_info
					     .remote_fundingkey,
					     commit_index);

	if (!wire_sync_write(ld->hsm_fd, take(msg)))
		fatal("Could not write to HSM: %s", strerror(errno));

	msg = wire_sync_read(tmpctx, ld->hsm_fd);
	if (!fromwire_hsmd_sign_commitment_tx_reply(msg, &sig))
		fatal("HSM gave bad sign_commitment_tx_reply %s",
		      tal_hex(tmpctx, msg));

	witness =
	    bitcoin_witness_2of2(last_tx, last_sig,
				 &sig, &channel->channel_info.remote_fundingkey,
				 &channel->local_funding_pubkey);

	bitcoin_tx_input_set_witness(last_tx, 0, take(witness));
}

static void remove_sig(struct bitcoin_tx *signed_tx)
{