common: `withdraw_tx()` now use the array of `struct bitcoin_tx_output` as parameter

common/funding_tx.c

@@ -26,7 +26,7 @@ struct bitcoin_tx *funding_tx(const tal_t *ctx,
 	struct bitcoin_tx *tx;
 	bool has_change = !amount_sat_eq(change, AMOUNT_SAT(0));
 
-	tx = tx_spending_utxos(ctx, chainparams, utxomap, bip32_base, has_change);
+	tx = tx_spending_utxos(ctx, chainparams, utxomap, bip32_base, has_change, 1);
 
 
 	wscript = bitcoin_redeem_2of2(tx, local_fundingkey, remote_fundingkey);

common/utxo.c

@@ -1,3 +1,4 @@
+#include <assert.h>
 #include <bitcoin/script.h>
 #include <common/key_derive.h>
 #include <common/utils.h>
@@ -52,11 +53,14 @@ struct bitcoin_tx *tx_spending_utxos(const tal_t *ctx,
 				     const struct chainparams *chainparams,
 				     const struct utxo **utxos,
 				     const struct ext_key *bip32_base,
-				     bool add_change_output)
+				     bool add_change_output,
+				     size_t num_output)
 {
 	struct pubkey key;
 	u8 *script;
-	size_t outcount = add_change_output ? 2 : 1;
+
+	assert(num_output);
+	size_t outcount = add_change_output ? 1 + num_output : num_output;
 	struct bitcoin_tx *tx = bitcoin_tx(ctx, chainparams, tal_count(utxos), outcount);
 
 	for (size_t i = 0; i < tal_count(utxos); i++) {

common/utxo.h

@@ -50,6 +50,7 @@ struct bitcoin_tx *tx_spending_utxos(const tal_t *ctx,
 				     const struct chainparams *chainparams,
 				     const struct utxo **utxos,
 				     const struct ext_key *bip32_base,
-				     bool add_change_output);
+				     bool add_change_output,
+				     size_t num_output);
 
 #endif /* LIGHTNING_COMMON_UTXO_H */

common/withdraw_tx.c

@@ -11,8 +11,7 @@
 struct bitcoin_tx *withdraw_tx(const tal_t *ctx,
 			       const struct chainparams *chainparams,
 			       const struct utxo **utxos,
-			       const u8 *destination,
-			       struct amount_sat withdraw_amount,
+			       struct bitcoin_tx_output **outputs,
 			       const struct pubkey *changekey,
 			       struct amount_sat change,
 			       const struct ext_key *bip32_base,
@@ -21,9 +20,10 @@ struct bitcoin_tx *withdraw_tx(const tal_t *ctx,
 	struct bitcoin_tx *tx;
 
 	tx = tx_spending_utxos(ctx, chainparams, utxos, bip32_base,
-			       !amount_sat_eq(change, AMOUNT_SAT(0)));
+			       !amount_sat_eq(change, AMOUNT_SAT(0)),
+			       tal_count(outputs));
 
-	bitcoin_tx_add_output(tx, destination, withdraw_amount);
+	bitcoin_tx_add_multi_outputs(tx, outputs);
 
 	if (!amount_sat_eq(change, AMOUNT_SAT(0))) {
 		const void *map[2];

common/withdraw_tx.h

@@ -2,6 +2,7 @@
 #define LIGHTNING_COMMON_WITHDRAW_TX_H
 #include "config.h"
 #include <bitcoin/chainparams.h>
+#include <bitcoin/tx.h>
 #include <ccan/short_types/short_types.h>
 #include <ccan/tal/tal.h>
 #include <common/amount.h>
@@ -19,8 +20,7 @@ struct utxo;
  * @ctx: context to tal from.
  * @chainparams: (in) the params for the created transaction.
  * @utxos: (in/out) tal_arr of UTXO pointers to spend (permuted to match)
- * @destination: (in) tal_arr of u8, scriptPubKey to send to.
- * @amount: (in) satoshis to send to the destination
+ * @outputs: (in) tal_arr of bitcoin_tx_output, scriptPubKeys with amount to send to.
  * @changekey: (in) key to send change to (only used if change_satoshis != 0).
  * @change: (in) amount to send as change.
  * @bip32_base: (in) bip32 base for key derivation, or NULL.
@@ -29,8 +29,7 @@ struct utxo;
 struct bitcoin_tx *withdraw_tx(const tal_t *ctx,
 			       const struct chainparams *chainparams,
 			       const struct utxo **utxos,
-			       const u8 *destination,
-			       struct amount_sat withdraw_amount,
+			       struct bitcoin_tx_output **outputs,
 			       const struct pubkey *changekey,
 			       struct amount_sat change,
 			       const struct ext_key *bip32_base,

hsmd/hsmd.c

@@ -1515,7 +1515,9 @@ static struct io_plan *handle_sign_withdrawal_tx(struct io_conn *conn,
 	struct bitcoin_tx *tx;
 	struct pubkey changekey;
 	u8 *scriptpubkey;
+	struct bitcoin_tx_output **outputs;
 
+	outputs = tal_arr(tmpctx, struct bitcoin_tx_output *, 0);
 	if (!fromwire_hsm_sign_withdrawal(tmpctx, msg_in, &satoshi_out,
 					  &change_out, &change_keyindex,
 					  &scriptpubkey, &utxos))
@@ -1525,9 +1527,14 @@ static struct io_plan *handle_sign_withdrawal_tx(struct io_conn *conn,
 		return bad_req_fmt(conn, c, msg_in,
 				   "Failed to get key %u", change_keyindex);
 
+	struct bitcoin_tx_output *output = tal(outputs,
+					       struct bitcoin_tx_output);
+	output->script = tal_steal(output, scriptpubkey);
+	output->amount = satoshi_out;
+	tal_arr_expand(&outputs, output);
 	tx = withdraw_tx(tmpctx, c->chainparams,
-			 cast_const2(const struct utxo **, utxos), scriptpubkey,
-			 satoshi_out, &changekey, change_out, NULL, NULL);
+			 cast_const2(const struct utxo **, utxos), outputs,
+			 &changekey, change_out, NULL, NULL);
 
 	sign_all_inputs(tx, utxos);
 

wallet/walletrpc.c

@@ -1,6 +1,7 @@
 #include <bitcoin/address.h>
 #include <bitcoin/base58.h>
 #include <bitcoin/script.h>
+#include <ccan/cast/cast.h>
 #include <ccan/tal/str/str.h>
 #include <common/addr.h>
 #include <common/bech32.h>
@@ -163,10 +164,12 @@ static struct command_result *json_prepare_tx(struct command *cmd,
 	struct command_result *res;
 	u32 *minconf, maxheight;
 	struct pubkey *changekey;
+	struct bitcoin_tx_output **outputs;
 
 	*utx = tal(cmd, struct unreleased_tx);
 	(*utx)->wtx = tal(*utx, struct wallet_tx);
 	wtx_init(cmd, (*utx)->wtx, AMOUNT_SAT(-1ULL));
+	outputs = tal_arr(tmpctx, struct bitcoin_tx_output *, 0);
 
 	if (!param(cmd, buffer, params,
 		   p_req("destination", param_bitcoin_address,
@@ -201,8 +204,14 @@ static struct command_result *json_prepare_tx(struct command *cmd,
 	} else
 		changekey = NULL;
 
-	(*utx)->tx = withdraw_tx(*utx, get_chainparams(cmd->ld), (*utx)->wtx->utxos,
-				 (*utx)->destination, (*utx)->wtx->amount,
+	struct bitcoin_tx_output *output = tal(outputs,
+					       struct bitcoin_tx_output);
+	output->script = tal_dup_arr(output, u8, (*utx)->destination,
+				     tal_count((*utx)->destination), 0);
+	output->amount = (*utx)->wtx->amount;
+	tal_arr_expand(&outputs, output);
+	(*utx)->tx = withdraw_tx(*utx, get_chainparams(cmd->ld),
+				 (*utx)->wtx->utxos, outputs,
 				 changekey, (*utx)->wtx->change,
 				 cmd->ld->wallet->bip32_base,
 				 &(*utx)->change_outnum);