tal: don't automatically register cleanup function.

It may interfere with other at_exit() calls, so let them call it manually.
Also, use memset to zero, which really does make valgrind notice any leaks.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

ccan/tal/tal.c

@@ -76,7 +76,6 @@ static void *(*allocfn)(size_t size) = malloc;
 static void *(*resizefn)(void *, size_t size) = realloc;
 static void (*freefn)(void *) = free;
 static void (*errorfn)(const char *msg) = (void *)abort;
-static bool initialized = false;
 /* Count on non-destrutor notifiers; often stays zero. */
 static size_t notifiers = 0;
 
@@ -101,23 +100,19 @@ static struct children *ignore_destroying_bit(struct children *parent_child)
 }
 
 /* This means valgrind can see leaks. */
-static void tal_cleanup(void)
+void tal_cleanup(void)
 {
 	struct tal_hdr *i;
 
-	while ((i = list_top(&null_parent.c.children, struct tal_hdr, list)))
+	while ((i = list_top(&null_parent.c.children, struct tal_hdr, list))) {
 		list_del(&i->list);
+		memset(i, 0, sizeof(*i));
+	}
 
 	/* Cleanup any taken pointers. */
 	take_cleanup();
 }
 
-/* For allocation failures inside ccan/take */
-static void take_alloc_failed(const void *p)
-{
-	tal_free(p);
-}
-
 /* We carefully start all real properties with a zero byte. */
 static bool is_literal(const struct prop_hdr *prop)
 {
@@ -344,11 +339,6 @@ static bool add_child(struct tal_hdr *parent, struct tal_hdr *child)
 	struct children *children = find_property(parent, CHILDREN);
 
         if (!children) {
-		if (unlikely(!initialized)) {
-			atexit(tal_cleanup);
-			take_allocfail(take_alloc_failed);
-			initialized = true;
-		}
 		children = add_child_property(parent, child);
 		if (!children)
 			return false;

ccan/tal/tal.h

@@ -327,6 +327,17 @@ void tal_set_backend(void *(*alloc_fn)(size_t size),
 	tal_expand_((void **)(a1p), (a2), sizeof**(a1p),	\
 		    (num2) + 0*sizeof(*(a1p) == (a2)))
 
+/**
+ * tal_cleanup - remove pointers from NULL node
+ *
+ * Internally, tal keeps a list of nodes allocated from @ctx NULL; this
+ * prevents valgrind from noticing memory leaks.  This re-initializes
+ * that list to empty.
+ *
+ * It also calls take_cleanup() for you.
+ */
+void tal_cleanup(void);
+
 
 /**
  * tal_check - set the allocation or error functions to use

ccan/tal/test/run-allocfail.c

@@ -148,5 +148,6 @@ int main(void)
 	ok1(err_count == when_to_fail - 1);
 
 	tal_free(p);
+	tal_cleanup();
 	return exit_status();
 }

ccan/tal/test/run-array.c

@@ -42,5 +42,6 @@ int main(void)
 	ok1(tal_first(parent) == NULL);
 	tal_free(parent);
 
+	tal_cleanup();
 	return exit_status();
 }

ccan/tal/test/run-count.c

@@ -82,5 +82,7 @@ int main(void)
 		tal_free(p2);
 		tal_free(p1);
 	}
+
+	tal_cleanup();
 	return exit_status();
 }

ccan/tal/test/run-destructor.c

@@ -63,5 +63,6 @@ int main(void)
 	tal_free(parent);
 	ok1(destroy_count == 4);
 
+	tal_cleanup();
 	return exit_status();
 }

ccan/tal/test/run-expand.c

@@ -28,5 +28,6 @@ int main(void)
 
 	tal_free(a);
 
+	tal_cleanup();
 	return exit_status();
 }

ccan/tal/test/run-free.c

@@ -21,5 +21,6 @@ int main(void)
 	tal_free(p);
 	ok1(errno == EINVAL);
 
+	tal_cleanup();
 	return exit_status();
 }

ccan/tal/test/run-groups-grow.c

@@ -42,5 +42,7 @@ int main(void)
 
 	/* We can expect some residue from having any child, but limited! */
 	ok1(num_allocated <= allocated_after_first);
+	tal_free(p);
+	tal_cleanup();
 	return exit_status();
 }

ccan/tal/test/run-iter.c

@@ -29,5 +29,6 @@ int main(void)
 		ok1(*p[i] == '1');
 		tal_free(p[i]);
 	}
+	tal_cleanup();
 	return exit_status();
 }

ccan/tal/test/run-named-debug.c

@@ -30,5 +30,6 @@ int main(void)
 	ok1(strcmp(tal_name(p), __FILE__ ":29:int[]") == 0);
 	tal_free(p);
 
+	tal_cleanup();
 	return exit_status();
 }

ccan/tal/test/run-named-nolabels.c

@@ -26,5 +26,6 @@ int main(void)
 
 	tal_free(p);
 
+	tal_cleanup();
 	return exit_status();
 }

ccan/tal/test/run-named.c

@@ -29,5 +29,6 @@ int main(void)
 	ok1(strcmp(tal_name(p), "int[]") == 0);
 	tal_free(p);
 
+	tal_cleanup();
 	return exit_status();
 }

ccan/tal/test/run-notifier.c

@@ -126,5 +126,6 @@ int main(void)
 	tal_del_notifier(new_ctx, resize_notifier);
 	tal_free(new_ctx);
 
+	tal_cleanup();
 	return exit_status();
 }

ccan/tal/test/run-overflow.c

@@ -94,5 +94,6 @@ int main(void)
 	ok1(error_count == 3);
 	tal_free(origpi);
 
+	tal_cleanup();
 	return exit_status();
 }

ccan/tal/test/run-steal.c

@@ -36,5 +36,6 @@ int main(void)
 	ok1(tal_parent(p[4]) == p[0]);
 	tal_free(p[0]);
 
+	tal_cleanup();
 	return exit_status();
 }

ccan/tal/test/run-take.c

@@ -52,5 +52,6 @@ int main(void)
 	ok1(tal_dup(NULL, char, take(c), 5, 5) == NULL);
 	ok1(!taken_any());
 
+	tal_cleanup();
 	return exit_status();
 }

ccan/tal/test/run-test-backend.c

@@ -75,5 +75,6 @@ int main(void)
 	/* Finally, free the parent. */
 	tal_free(p);
 
+	tal_cleanup();
 	return exit_status();
 }

ccan/tal/test/run.c

@@ -56,5 +56,6 @@ int main(void)
 	}
 	tal_free(parent);
 
+	tal_cleanup();
 	return exit_status();
 }