gossipd: wire up memleak detection.

For simplicity we dump leaks to logs, and just return a bool to master.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

gossipd/broadcast.c

@@ -4,6 +4,7 @@
 #include <ccan/crypto/siphash24/siphash24.h>
 #include <ccan/htable/htable_type.h>
 #include <ccan/mem/mem.h>
+#include <common/memleak.h>
 #include <common/pseudorand.h>
 #include <common/status.h>
 #include <common/type_to_string.h>

gossipd/broadcast.h

@@ -35,4 +35,5 @@ const u8 *next_broadcast(struct broadcast_state *bstate,
  * NULL. */
 struct broadcast_state *broadcast_state_check(struct broadcast_state *b,
 					      const char *abortstr);
+
 #endif /* LIGHTNING_GOSSIPD_BROADCAST_H */

gossipd/gossip_wire.csv

@@ -135,6 +135,12 @@ gossip_outpoint_spent,,short_channel_id,struct short_channel_id
 # master -> gossipd: stop gossip timers.
 gossip_dev_suppress,3032
 
+# master -> gossipd: do you have a memleak?
+gossip_dev_memleak,3033
+
+gossip_dev_memleak_reply,3133
+gossip_dev_memleak_reply,,leak,bool
+
 #include <common/bolt11.h>
 
 # master -> gossipd: get route_info for our incoming channels

gossipd/gossipd.c

@@ -2342,6 +2342,26 @@ static struct io_plan *dev_gossip_suppress(struct io_conn *conn,
 	suppress_gossip = true;
 	return daemon_conn_read_next(conn, daemon->master);
 }
+
+static struct io_plan *dev_gossip_memleak(struct io_conn *conn,
+					  struct daemon *daemon,
+					  const u8 *msg)
+{
+	struct htable *memtable;
+	bool found_leak;
+
+	memtable = memleak_enter_allocations(tmpctx, msg, msg);
+
+	/* Now delete daemon and those which it has pointers to. */
+	memleak_remove_referenced(memtable, daemon);
+	memleak_remove_routing_tables(memtable, daemon->rstate);
+
+	found_leak = dump_memleak(memtable);
+	daemon_conn_send(daemon->master,
+			 take(towire_gossip_dev_memleak_reply(NULL,
+							      found_leak)));
+	return daemon_conn_read_next(conn, daemon->master);
+}
 #endif /* DEVELOPER */
 
 /*~ lightningd: so, tell me about this channel, so we can forward to it. */
@@ -2556,12 +2576,15 @@ static struct io_plan *recv_req(struct io_conn *conn,
 		return dev_set_max_scids_encode_size(conn, daemon, msg);
 	case WIRE_GOSSIP_DEV_SUPPRESS:
 		return dev_gossip_suppress(conn, daemon, msg);
+	case WIRE_GOSSIP_DEV_MEMLEAK:
+		return dev_gossip_memleak(conn, daemon, msg);
 #else
 	case WIRE_GOSSIP_QUERY_SCIDS:
 	case WIRE_GOSSIP_SEND_TIMESTAMP_FILTER:
 	case WIRE_GOSSIP_QUERY_CHANNEL_RANGE:
 	case WIRE_GOSSIP_DEV_SET_MAX_SCIDS_ENCODE_SIZE:
 	case WIRE_GOSSIP_DEV_SUPPRESS:
+	case WIRE_GOSSIP_DEV_MEMLEAK:
 		break;
 #endif /* !DEVELOPER */
 
@@ -2575,6 +2598,7 @@ static struct io_plan *recv_req(struct io_conn *conn,
 	case WIRE_GOSSIP_GET_CHANNEL_PEER_REPLY:
 	case WIRE_GOSSIP_GET_INCOMING_CHANNELS_REPLY:
 	case WIRE_GOSSIP_GET_TXOUT:
+	case WIRE_GOSSIP_DEV_MEMLEAK_REPLY:
 		break;
 	}
 

gossipd/routing.c

@@ -7,6 +7,7 @@
 #include <ccan/mem/mem.h>
 #include <ccan/tal/str/str.h>
 #include <common/features.h>
+#include <common/memleak.h>
 #include <common/pseudorand.h>
 #include <common/status.h>
 #include <common/type_to_string.h>
@@ -1715,6 +1716,16 @@ void route_prune(struct routing_state *rstate)
 	tal_free(pruned);
 }
 
+#if DEVELOPER
+void memleak_remove_routing_tables(struct htable *memtable,
+				   const struct routing_state *rstate)
+{
+	memleak_remove_htable(memtable, &rstate->nodes->raw);
+	memleak_remove_htable(memtable, &rstate->pending_node_map->raw);
+	memleak_remove_uintmap(memtable, &rstate->broadcasts->broadcasts);
+}
+#endif /* DEVELOPER */
+
 bool handle_local_add_channel(struct routing_state *rstate, const u8 *msg)
 {
 	struct short_channel_id scid;

gossipd/routing.h

@@ -327,4 +327,8 @@ bool routing_add_node_announcement(struct routing_state *rstate,
  */
 bool handle_local_add_channel(struct routing_state *rstate, const u8 *msg);
 
+#if DEVELOPER
+void memleak_remove_routing_tables(struct htable *memtable,
+				   const struct routing_state *rstate);
+#endif
 #endif /* LIGHTNING_GOSSIPD_ROUTING_H */

gossipd/test/run-bench-find_route.c

@@ -140,6 +140,15 @@ const char *wire_type_name(int e UNNEEDED)
 { fprintf(stderr, "wire_type_name called!\n"); abort(); }
 /* AUTOGENERATED MOCKS END */
 
+#if DEVELOPER
+/* Generated stub for memleak_remove_htable */
+void memleak_remove_htable(struct htable *memtable UNNEEDED, const struct htable *ht UNNEEDED)
+{ fprintf(stderr, "memleak_remove_htable called!\n"); abort(); }
+/* Generated stub for memleak_remove_intmap_ */
+void memleak_remove_intmap_(struct htable *memtable UNNEEDED, const struct intmap *m UNNEEDED)
+{ fprintf(stderr, "memleak_remove_intmap_ called!\n"); abort(); }
+#endif
+
 /* Updates existing route if required. */
 static void add_connection(struct routing_state *rstate,
 					const struct pubkey *from,

gossipd/test/run-find_route-specific.c

@@ -104,6 +104,15 @@ const char *wire_type_name(int e UNNEEDED)
 { fprintf(stderr, "wire_type_name called!\n"); abort(); }
 /* AUTOGENERATED MOCKS END */
 
+#if DEVELOPER
+/* Generated stub for memleak_remove_htable */
+void memleak_remove_htable(struct htable *memtable UNNEEDED, const struct htable *ht UNNEEDED)
+{ fprintf(stderr, "memleak_remove_htable called!\n"); abort(); }
+/* Generated stub for memleak_remove_intmap_ */
+void memleak_remove_intmap_(struct htable *memtable UNNEEDED, const struct intmap *m UNNEEDED)
+{ fprintf(stderr, "memleak_remove_intmap_ called!\n"); abort(); }
+#endif
+
 const void *trc;
 
 static struct half_chan *

gossipd/test/run-find_route.c

@@ -102,6 +102,15 @@ const char *wire_type_name(int e UNNEEDED)
 { fprintf(stderr, "wire_type_name called!\n"); abort(); }
 /* AUTOGENERATED MOCKS END */
 
+#if DEVELOPER
+/* Generated stub for memleak_remove_htable */
+void memleak_remove_htable(struct htable *memtable UNNEEDED, const struct htable *ht UNNEEDED)
+{ fprintf(stderr, "memleak_remove_htable called!\n"); abort(); }
+/* Generated stub for memleak_remove_intmap_ */
+void memleak_remove_intmap_(struct htable *memtable UNNEEDED, const struct intmap *m UNNEEDED)
+{ fprintf(stderr, "memleak_remove_intmap_ called!\n"); abort(); }
+#endif
+
 /* Updates existing route if required. */
 static void add_connection(struct routing_state *rstate,
 					      const struct pubkey *from,

lightningd/gossip_control.c

@@ -118,6 +118,7 @@ static unsigned gossip_msg(struct subd *gossip, const u8 *msg, const int *fds)
 	case WIRE_GOSSIP_DEV_SET_MAX_SCIDS_ENCODE_SIZE:
 	case WIRE_GOSSIP_DEV_SUPPRESS:
 	case WIRE_GOSSIP_LOCAL_CHANNEL_CLOSE:
+	case WIRE_GOSSIP_DEV_MEMLEAK:
 	/* This is a reply, so never gets through to here. */
 	case WIRE_GOSSIP_GETNODES_REPLY:
 	case WIRE_GOSSIP_GETROUTE_REPLY:
@@ -126,6 +127,7 @@ static unsigned gossip_msg(struct subd *gossip, const u8 *msg, const int *fds)
 	case WIRE_GOSSIP_QUERY_CHANNEL_RANGE_REPLY:
 	case WIRE_GOSSIP_GET_CHANNEL_PEER_REPLY:
 	case WIRE_GOSSIP_GET_INCOMING_CHANNELS_REPLY:
+	case WIRE_GOSSIP_DEV_MEMLEAK_REPLY:
 		break;
 
 	case WIRE_GOSSIP_PING_REPLY:

lightningd/memdump.c

@@ -5,12 +5,15 @@
 #include <ccan/tal/str/str.h>
 #include <common/daemon.h>
 #include <common/memleak.h>
+#include <common/timeout.h>
+#include <gossipd/gen_gossip_wire.h>
 #include <lightningd/chaintopology.h>
 #include <lightningd/jsonrpc.h>
 #include <lightningd/jsonrpc_errors.h>
 #include <lightningd/lightningd.h>
 #include <lightningd/log.h>
 #include <lightningd/param.h>
+#include <lightningd/subd.h>
 #include <stdio.h>
 
 static void json_add_ptr(struct json_stream *response, const char *name,
@@ -111,7 +114,8 @@ static void json_add_backtrace(struct json_stream *response,
 
 static void scan_mem(struct command *cmd,
 		     struct json_stream *response,
-		     struct lightningd *ld)
+		     struct lightningd *ld,
+		     const struct subd *leaking_subd)
 {
 	struct htable *memtable;
 	const tal_t *i;
@@ -147,14 +151,64 @@ static void scan_mem(struct command *cmd,
 		json_array_end(response);
 		json_object_end(response);
 	}
+
+	if (leaking_subd) {
+		json_object_start(response, NULL);
+		json_add_string(response, "subdaemon", leaking_subd->name);
+		json_object_end(response);
+	}
 	json_array_end(response);
 }
 
+struct leak_info {
+	struct command *cmd;
+	struct subd *leaker;
+};
+
+static void report_leak_info2(struct leak_info *leak_info)
+{
+	struct json_stream *response = json_stream_success(leak_info->cmd);
+
+	json_object_start(response, NULL);
+	scan_mem(leak_info->cmd, response, leak_info->cmd->ld, leak_info->leaker);
+	json_object_end(response);
+
+	command_success(leak_info->cmd, response);
+}
+
+static void report_leak_info(struct command *cmd, struct subd *leaker)
+{
+	struct leak_info *leak_info = tal(cmd, struct leak_info);
+
+	leak_info->cmd = cmd;
+	leak_info->leaker = leaker;
+
+	/* Leak detection in a reply handler thinks we're leaking conn. */
+	notleak(new_reltimer(&leak_info->cmd->ld->timers, leak_info->cmd,
+			     time_from_sec(0),
+			     report_leak_info2, leak_info));
+}
+
+static void gossip_dev_memleak_done(struct subd *gossipd,
+				    const u8 *reply,
+				    const int *fds UNUSED,
+				    struct command *cmd)
+{
+	bool found_leak;
+
+	if (!fromwire_gossip_dev_memleak_reply(reply, &found_leak)) {
+		command_fail(cmd, LIGHTNINGD, "Bad gossip_dev_memleak");
+		return;
+	}
+
+	report_leak_info(cmd, found_leak ? gossipd : NULL);
+}
+
 static void json_memleak(struct command *cmd,
 			 const char *buffer UNNEEDED,
 			 const jsmntok_t *params UNNEEDED)
 {
-	struct json_stream *response;
+	struct lightningd *ld = cmd->ld;
 
 	if (!param(cmd, buffer, params, NULL))
 		return;
@@ -165,12 +219,9 @@ static void json_memleak(struct command *cmd,
 		return;
 	}
 
-	response = json_stream_success(cmd);
+	subd_req(ld->gossip, ld->gossip, take(towire_gossip_dev_memleak(NULL)),
-	json_object_start(response, NULL);
+		 -1, 0, gossip_dev_memleak_done, cmd);
-	scan_mem(cmd, response, cmd->ld);
+	command_still_pending(cmd);
-	json_object_end(response);
-
-	command_success(cmd, response);
 }
 
 static const struct json_command dev_memleak_command = {