lightningd: add dev-memdump command.

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

Makefile

@@ -20,7 +20,7 @@ endif
 DEVELOPER := 1
 
 ifeq ($(DEVELOPER),1)
-DEV_CFLAGS=-DDEVELOPER=1
+DEV_CFLAGS=-DDEVELOPER=1 -DCCAN_TAL_DEBUG=1 -DCCAN_TAKE_DEBUG=1
 else
 DEV_CFLAGS=-DDEVELOPER=0
 endif
@@ -143,7 +143,7 @@ ALL_PROGRAMS =
 
 CWARNFLAGS := -Werror -Wall -Wundef -Wmissing-prototypes -Wmissing-declarations -Wstrict-prototypes -Wold-style-definition
 CDEBUGFLAGS := -std=gnu11 -g -fstack-protector
-CFLAGS = $(CWARNFLAGS) $(CDEBUGFLAGS) -I $(CCANDIR) $(EXTERNAL_INCLUDE_FLAGS) -I . $(FEATURES) $(COVFLAGS) $(DEV_CFLAGS) -DSHACHAIN_BITS=48 -DCCAN_TAKE_DEBUG=1
+CFLAGS = $(CWARNFLAGS) $(CDEBUGFLAGS) -I $(CCANDIR) $(EXTERNAL_INCLUDE_FLAGS) -I . $(FEATURES) $(COVFLAGS) $(DEV_CFLAGS) -DSHACHAIN_BITS=48
 
 LDLIBS = -lgmp -lsqlite3 $(COVFLAGS)
 

lightningd/Makefile

@@ -66,6 +66,7 @@ LIGHTNINGD_SRC :=				\
 # Source files without corresponding headers
 LIGHTNINGD_SRC_NOHDR :=				\
 	lightningd/dev_ping.c			\
+	lightningd/memdump.c
 
 LIGHTNINGD_OBJS := $(LIGHTNINGD_SRC:.c=.o) $(LIGHTNINGD_SRC_NOHDR:.c=.o)
 

lightningd/memdump.c

@@ -0,0 +1,63 @@
+/* Only possible if we're in developer mode. */
+#ifdef DEVELOPER
+#include <lightningd/jsonrpc.h>
+#include <stdio.h>
+
+static void json_add_ptr(struct json_result *response, const char *name,
+			 const void *ptr)
+{
+	char ptrstr[STR_MAX_CHARS(void *)];
+	sprintf(ptrstr, "%p", ptr);
+	json_add_string(response, name, ptrstr);
+}
+
+static void add_memdump(struct json_result *response,
+			const char *name, const tal_t *root,
+			struct command *cmd)
+{
+	const tal_t *i;
+
+	json_array_start(response, name);
+	for (i = tal_first(root); i; i = tal_next(i)) {
+		const char *name = tal_name(i);
+
+		/* Don't try to dump this command! */
+		if (i == cmd || i == cmd->jcon)
+			continue;
+
+		/* Don't dump logs, we know they grow. */
+		if (name && streq(name, "struct log_book"))
+			continue;
+
+		json_object_start(response, NULL);
+		json_add_ptr(response, "parent", tal_parent(i));
+		json_add_ptr(response, "value", i);
+		if (name)
+			json_add_string(response, "label", name);
+
+		if (tal_first(i))
+			add_memdump(response, "children", i, cmd);
+		json_object_end(response);
+	}
+	json_array_end(response);
+}
+
+static void json_memdump(struct command *cmd,
+			 const char *buffer UNNEEDED,
+			 const jsmntok_t *params UNNEEDED)
+{
+	struct json_result *response = new_json_result(cmd);
+
+	add_memdump(response, NULL, NULL, cmd);
+
+	command_success(cmd, response);
+}
+
+static const struct json_command dev_memdump_command = {
+	"dev-memdump",
+	json_memdump,
+	"Dump the memory objects currently used",
+	"Debugging tool for memory leaks"
+};
+AUTODATA(json_command, &dev_memdump_command);
+#endif /* DEVELOPER */