plugin: simplify hooks calling methods, and make lifetime requirement…

…s explicit.

They callback must take ownership of the payload (almost all do, but
now it's explicit).

And since the payload and cb_arg arguments to plugin_hook_call_() are
always identical, make them a single parameter.

Signed-off-by: Rusty Russell <[email protected]>

lightningd/invoice.c

@@ -231,7 +231,7 @@ static const u8 *hook_gives_failmsg(const tal_t *ctx,
 }
 
 static void
-invoice_payment_hook_cb(struct invoice_payment_hook_payload *payload,
+invoice_payment_hook_cb(struct invoice_payment_hook_payload *payload STEALS,
 			const char *buffer,
 			const jsmntok_t *toks)
 {
@@ -281,7 +281,6 @@ invoice_payment_hook_cb(struct invoice_payment_hook_payload *payload,
 REGISTER_PLUGIN_HOOK(invoice_payment,
 		     PLUGIN_HOOK_SINGLE,
 		     invoice_payment_hook_cb,
-		     struct invoice_payment_hook_payload *,
 		     invoice_payment_serialize,
 		     struct invoice_payment_hook_payload *);
 
@@ -360,15 +359,15 @@ void invoice_try_pay(struct lightningd *ld,
 {
 	struct invoice_payment_hook_payload *payload;
 
-	payload = tal(ld, struct invoice_payment_hook_payload);
+	payload = tal(NULL, struct invoice_payment_hook_payload);
 	payload->ld = ld;
 	payload->label = tal_steal(payload, details->label);
 	payload->msat = set->so_far;
 	payload->preimage = details->r;
 	payload->set = set;
 	tal_add_destructor2(set, invoice_payload_remove_set, payload);
 
-	plugin_hook_call_invoice_payment(ld, payload, payload);
+	plugin_hook_call_invoice_payment(ld, payload);
 }
 
 static bool hsm_sign_b11(const u5 *u5bytes,

lightningd/jsonrpc.c

@@ -29,6 +29,7 @@
 #include <common/memleak.h>
 #include <common/param.h>
 #include <common/timeout.h>
+#include <common/utils.h>
 #include <common/version.h>
 #include <common/wireaddr.h>
 #include <errno.h>
@@ -676,13 +677,16 @@ static void replace_command(struct rpc_command_hook_payload *p,
 }
 
 static void
-rpc_command_hook_callback(struct rpc_command_hook_payload *p,
+rpc_command_hook_callback(struct rpc_command_hook_payload *p STEALS,
                           const char *buffer, const jsmntok_t *resulttok)
 {
 	const jsmntok_t *tok, *params, *custom_return;
 	const jsmntok_t *innerresulttok;
 	struct json_stream *response;
 
+	/* Free payload with cmd */
+	tal_steal(p->cmd, p);
+
 	params = json_get_member(p->buffer, p->request, "params");
 
 	/* If no plugin registered, just continue command execution. Same if
@@ -767,13 +771,12 @@ rpc_command_hook_callback(struct rpc_command_hook_payload *p,
 
 REGISTER_PLUGIN_HOOK(rpc_command, PLUGIN_HOOK_SINGLE,
 		     rpc_command_hook_callback,
-                     struct rpc_command_hook_payload *,
                      rpc_command_hook_serialize,
                      struct rpc_command_hook_payload *);
 
 static void call_rpc_command_hook(struct rpc_command_hook_payload *p)
 {
-	plugin_hook_call_rpc_command(p->cmd->ld, p, p);
+	plugin_hook_call_rpc_command(p->cmd->ld, p);
 }
 
 /* We return struct command_result so command_fail return value has a natural
@@ -842,7 +845,7 @@ parse_request(struct json_connection *jcon, const jsmntok_t tok[])
 				    jcon->buffer + method->start);
 	}
 
-	rpc_hook = tal(c, struct rpc_command_hook_payload);
+	rpc_hook = tal(NULL, struct rpc_command_hook_payload);
 	rpc_hook->cmd = c;
 	/* Duplicate since we might outlive the connection */
 	rpc_hook->buffer = tal_dup_talarr(rpc_hook, char, jcon->buffer);

lightningd/onion_message.c

@@ -41,7 +41,7 @@ onion_message_serialize(struct onion_message_hook_payload *payload,
 }
 
 static void
-onion_message_hook_cb(struct onion_message_hook_payload *payload,
+onion_message_hook_cb(struct onion_message_hook_payload *payload STEALS,
 			 const char *buffer,
 			 const jsmntok_t *toks)
 {
@@ -53,7 +53,6 @@ onion_message_hook_cb(struct onion_message_hook_payload *payload,
 REGISTER_PLUGIN_HOOK(onion_message,
 		     PLUGIN_HOOK_CHAIN,
 		     onion_message_hook_cb,
-		     struct onion_message_hook_payload *,
 		     onion_message_serialize,
 		     struct onion_message_hook_payload *);
 
@@ -112,7 +111,7 @@ void handle_onionmsg_to_us(struct channel *channel, const u8 *msg)
 	log_debug(channel->log, "Got onionmsg%s%s",
 		  payload->reply_blinding ? " reply_blinding": "",
 		  payload->reply_path ? " reply_path": "");
-	plugin_hook_call_onion_message(ld, payload, payload);
+	plugin_hook_call_onion_message(ld, payload);
 }
 
 void handle_onionmsg_forward(struct channel *channel, const u8 *msg)

lightningd/opening_control.c

@@ -754,7 +754,7 @@ static void openchannel_payload_remove_openingd(struct subd *openingd,
 	payload->openingd = NULL;
 }
 
-static void openchannel_hook_cb(struct openchannel_hook_payload *payload,
+static void openchannel_hook_cb(struct openchannel_hook_payload *payload STEALS,
 			    const char *buffer,
 			    const jsmntok_t *toks)
 {
@@ -829,7 +829,6 @@ static void openchannel_hook_cb(struct openchannel_hook_payload *payload,
 REGISTER_PLUGIN_HOOK(openchannel,
 		     PLUGIN_HOOK_SINGLE,
 		     openchannel_hook_cb,
-		     struct openchannel_hook_payload *,
 		     openchannel_hook_serialize,
 		     struct openchannel_hook_payload *);
 
@@ -847,7 +846,7 @@ static void opening_got_offer(struct subd *openingd,
 		return;
 	}
 
-	payload = tal(openingd->ld, struct openchannel_hook_payload);
+	payload = tal(openingd, struct openchannel_hook_payload);
 	payload->openingd = openingd;
 	if (!fromwire_opening_got_offer(payload, msg,
 					&payload->funding_satoshis,
@@ -868,7 +867,7 @@ static void opening_got_offer(struct subd *openingd,
 	}
 
 	tal_add_destructor2(openingd, openchannel_payload_remove_openingd, payload);
-	plugin_hook_call_openchannel(openingd->ld, payload, payload);
+	plugin_hook_call_openchannel(openingd->ld, payload);
 }
 
 static unsigned int openingd_msg(struct subd *openingd,

lightningd/peer_control.c

@@ -860,7 +860,7 @@ peer_connected_serialize(struct peer_connected_hook_payload *payload,
 }
 
 static void
-peer_connected_hook_cb(struct peer_connected_hook_payload *payload,
+peer_connected_hook_cb(struct peer_connected_hook_payload *payload STEALS,
 		       const char *buffer,
 		       const jsmntok_t *toks)
 {
@@ -974,7 +974,6 @@ peer_connected_hook_cb(struct peer_connected_hook_payload *payload,
 
 REGISTER_PLUGIN_HOOK(peer_connected, PLUGIN_HOOK_SINGLE,
 		     peer_connected_hook_cb,
-		     struct peer_connected_hook_payload *,
 		     peer_connected_serialize,
 		     struct peer_connected_hook_payload *);
 
@@ -1018,7 +1017,7 @@ void peer_connected(struct lightningd *ld, const u8 *msg,
 	assert(!peer->uncommitted_channel);
 	hook_payload->channel = peer_active_channel(peer);
 
-	plugin_hook_call_peer_connected(ld, hook_payload, hook_payload);
+	plugin_hook_call_peer_connected(ld, hook_payload);
 }
 
 /* FIXME: Unify our watch code so we get notified by txout, instead, like
@@ -2297,7 +2296,7 @@ struct custommsg_payload {
 	const u8 *msg;
 };
 
-static void custommsg_callback(struct custommsg_payload *payload,
+static void custommsg_callback(struct custommsg_payload *payload STEALS,
 			       const char *buffer, const jsmntok_t *toks)
 {
 	tal_free(payload);
@@ -2310,8 +2309,9 @@ static void custommsg_payload_serialize(struct custommsg_payload *payload,
 	json_add_node_id(stream, "peer_id", &payload->peer_id);
 }
 
-REGISTER_PLUGIN_HOOK(custommsg, PLUGIN_HOOK_SINGLE, custommsg_callback,
-		     struct custommsg_payload *, custommsg_payload_serialize,
+REGISTER_PLUGIN_HOOK(custommsg, PLUGIN_HOOK_SINGLE,
+		     custommsg_callback,
+		     custommsg_payload_serialize,
 		     struct custommsg_payload *);
 
 void handle_custommsg_in(struct lightningd *ld, const struct node_id *peer_id,
@@ -2329,7 +2329,7 @@ void handle_custommsg_in(struct lightningd *ld, const struct node_id *peer_id,
 
 	p->peer_id = *peer_id;
 	p->msg = tal_steal(p, custommsg);
-	plugin_hook_call_custommsg(ld, p, p);
+	plugin_hook_call_custommsg(ld, p);
 }
 
 static struct command_result *json_sendcustommsg(struct command *cmd,

lightningd/peer_htlcs.c

@@ -976,7 +976,7 @@ static void htlc_accepted_hook_serialize(struct htlc_accepted_hook_payload *p,
  * Callback when a plugin answers to the htlc_accepted hook
  */
 static void
-htlc_accepted_hook_callback(struct htlc_accepted_hook_payload *request,
+htlc_accepted_hook_callback(struct htlc_accepted_hook_payload *request STEALS,
 			    const char *buffer, const jsmntok_t *toks)
 {
 	struct route_step *rs = request->route_step;
@@ -1027,7 +1027,6 @@ htlc_accepted_hook_callback(struct htlc_accepted_hook_payload *request,
 
 REGISTER_PLUGIN_HOOK(htlc_accepted, PLUGIN_HOOK_CHAIN,
 		     htlc_accepted_hook_callback,
-		     struct htlc_accepted_hook_payload *,
 		     htlc_accepted_hook_serialize,
 		     struct htlc_accepted_hook_payload *);
 
@@ -1160,7 +1159,7 @@ static bool peer_accepted_htlc(const tal_t *ctx,
 		goto fail;
 	}
 
-	hook_payload = tal(hin, struct htlc_accepted_hook_payload);
+	hook_payload = tal(NULL, struct htlc_accepted_hook_payload);
 
 	hook_payload->route_step = tal_steal(hook_payload, rs);
 	hook_payload->payload = onion_decode(hook_payload, rs,
@@ -1186,7 +1185,7 @@ static bool peer_accepted_htlc(const tal_t *ctx,
 #endif
 		hook_payload->next_blinding = NULL;
 
-	plugin_hook_call_htlc_accepted(ld, hook_payload, hook_payload);
+	plugin_hook_call_htlc_accepted(ld, hook_payload);
 
 	/* Falling through here is ok, after all the HTLC locked */
 	return true;

lightningd/plugin_hook.c

@@ -14,7 +14,6 @@ struct plugin_hook_request {
 	struct plugin *plugin;
 	const struct plugin_hook *hook;
 	void *cb_arg;
-	void *payload;
 	struct db *db;
 	struct lightningd *ld;
 };
@@ -221,13 +220,13 @@ static void plugin_hook_call_next(struct plugin_hook_request *ph_req)
 				    plugin_get_log(ph_req->plugin),
 				    plugin_hook_callback, ph_req);
 
-	hook->serialize_payload(ph_req->payload, req->stream);
+	hook->serialize_payload(ph_req->cb_arg, req->stream);
 	jsonrpc_request_end(req);
 	plugin_request_send(ph_req->plugin, req);
 }
 
 void plugin_hook_call_(struct lightningd *ld, const struct plugin_hook *hook,
-		       void *payload, void *cb_arg)
+		       tal_t *cb_arg STEALS)
 {
 	struct plugin_hook_request *ph_req;
 	struct plugin_hook_call_link *link;
@@ -239,9 +238,8 @@ void plugin_hook_call_(struct lightningd *ld, const struct plugin_hook *hook,
 		 * to eventually to inspect in-flight requests. */
 		ph_req = notleak(tal(hook->plugins, struct plugin_hook_request));
 		ph_req->hook = hook;
-		ph_req->cb_arg = cb_arg;
+		ph_req->cb_arg = tal_steal(ph_req, cb_arg);
 		ph_req->db = ld->wallet->db;
-		ph_req->payload = tal_steal(ph_req, payload);
 		ph_req->ld = ld;
 
 		list_head_init(&ph_req->call_chain);

lightningd/plugin_hook.h

@@ -28,13 +28,14 @@
  * delivery to the plugin, and from a JSON-object to the internal
  * representation:
  *
- * - `serialize_payload` which takes a payload of type `payload_type`
+ * - `serialize_payload` which takes a payload of type `cb_arg_type`
  *   and serializes it into the given `json_stream`. `
  *
  * - `response_cb` is called once the plugin has responded (or with
  *   buffer == NULL if there's no plugin).  In addition an arbitrary
  *   additional argument of type `cb_arg_type` can be passed along
- *   that may contain any additional context necessary.
+ *   that may contain any additional context necessary.  It must free
+ *   or otherwise take ownership of the cb_arg_type argument.
  *
  *
  * To make hook invocations easier, each hook registered with
@@ -69,7 +70,7 @@ AUTODATA_TYPE(hooks, struct plugin_hook);
  * wrappers generated by the `PLUGIN_HOOK_REGISTER` macro.
  */
 void plugin_hook_call_(struct lightningd *ld, const struct plugin_hook *hook,
-		       void *payload, void *cb_arg);
+		       tal_t *cb_arg STEALS);
 
 
 /* Create a small facade in from of `plugin_hook_call_` to make sure
@@ -78,13 +79,11 @@ void plugin_hook_call_(struct lightningd *ld, const struct plugin_hook *hook,
  * the method-name is correct for the call.
  */
 /* FIXME: Find a way to avoid back-to-back declaration and definition */
-#define PLUGIN_HOOK_CALL_DEF(name, payload_type, response_cb_arg_type)         \
+#define PLUGIN_HOOK_CALL_DEF(name, cb_arg_type)				       \
 	UNNEEDED static inline void plugin_hook_call_##name(                   \
-	    struct lightningd *ld, payload_type payload,                       \
-	    response_cb_arg_type cb_arg)                                       \
+	    struct lightningd *ld, cb_arg_type cb_arg STEALS)                  \
 	{                                                                      \
-		plugin_hook_call_(ld, &name##_hook_gen, (void *)payload,       \
-				  (void *)cb_arg);                             \
+		plugin_hook_call_(ld, &name##_hook_gen, cb_arg);               \
 	}
 
 /* Typechecked registration of a plugin hook. We check that the
@@ -95,23 +94,22 @@ void plugin_hook_call_(struct lightningd *ld, const struct plugin_hook *hook,
  * response_cb function accepts the deserialized response format and
  * an arbitrary extra argument used to maintain context.
  */
-#define REGISTER_PLUGIN_HOOK(name, type, response_cb, response_cb_arg_type,    \
-			     serialize_payload, payload_type)                  \
+#define REGISTER_PLUGIN_HOOK(name, type, response_cb,			       \
+			     serialize_payload, cb_arg_type)	               \
 	struct plugin_hook name##_hook_gen = {                                 \
 	    stringify(name),                                                   \
 	    type,                                                              \
 	    typesafe_cb_cast(                                                  \
-		void (*)(void *, const char *, const jsmntok_t *),             \
-		void (*)(response_cb_arg_type, const char *,                   \
-			 const jsmntok_t *),                                   \
+		void (*)(void *STEALS, const char *, const jsmntok_t *),       \
+		void (*)(cb_arg_type STEALS, const char *, const jsmntok_t *), \
 		response_cb),                                                  \
 	    typesafe_cb_cast(void (*)(void *, struct json_stream *),           \
-			     void (*)(payload_type, struct json_stream *),     \
+			     void (*)(cb_arg_type, struct json_stream *),      \
 			     serialize_payload),                               \
 	    NULL, /* .plugins */                                               \
 	};                                                                     \
 	AUTODATA(hooks, &name##_hook_gen);                                     \
-	PLUGIN_HOOK_CALL_DEF(name, payload_type, response_cb_arg_type);
+	PLUGIN_HOOK_CALL_DEF(name, cb_arg_type)
 
 bool plugin_hook_register(struct plugin *plugin, const char *method);
 

lightningd/test/run-invoice-select-inchan.c

@@ -375,7 +375,7 @@ void per_peer_state_set_fds(struct per_peer_state *pps UNNEEDED,
 { fprintf(stderr, "per_peer_state_set_fds called!\n"); abort(); }
 /* Generated stub for plugin_hook_call_ */
 void plugin_hook_call_(struct lightningd *ld UNNEEDED, const struct plugin_hook *hook UNNEEDED,
-		       void *payload UNNEEDED, void *cb_arg UNNEEDED)
+		       tal_t *cb_arg UNNEEDED)
 { fprintf(stderr, "plugin_hook_call_ called!\n"); abort(); }
 /* Generated stub for subd_release_channel */
 void subd_release_channel(struct subd *owner UNNEEDED, void *channel UNNEEDED)

lightningd/test/run-jsonrpc.c

@@ -96,7 +96,7 @@ struct command_result *param_tok(struct command *cmd UNNEEDED, const char *name
 { fprintf(stderr, "param_tok called!\n"); abort(); }
 /* Generated stub for plugin_hook_call_ */
 void plugin_hook_call_(struct lightningd *ld UNNEEDED, const struct plugin_hook *hook UNNEEDED,
-		       void *payload UNNEEDED, void *cb_arg UNNEEDED)
+		       tal_t *cb_arg UNNEEDED)
 { fprintf(stderr, "plugin_hook_call_ called!\n"); abort(); }
 /* AUTOGENERATED MOCKS END */
 

wallet/test/run-wallet.c

@@ -547,7 +547,7 @@ void per_peer_state_set_fds(struct per_peer_state *pps UNNEEDED,
 { fprintf(stderr, "per_peer_state_set_fds called!\n"); abort(); }
 /* Generated stub for plugin_hook_call_ */
 void plugin_hook_call_(struct lightningd *ld UNNEEDED, const struct plugin_hook *hook UNNEEDED,
-		       void *payload UNNEEDED, void *cb_arg UNNEEDED)
+		       tal_t *cb_arg UNNEEDED)
 { fprintf(stderr, "plugin_hook_call_ called!\n"); abort(); }
 /* Generated stub for process_onionpacket */
 struct route_step *process_onionpacket(