Function free_all_channels

lightningd/lightningd.c:520–569

~ We like to free everything on exit, so valgrind doesn't complain (valgrind * is an awesome runtime memory usage detector for C and C++ programs). In * some ways it would be neater not to do this, but it turns out some * transient objects still need cleaning. */

 * some ways it would be neater not to do this, but it turns out some
 * transient objects still need cleaning. */
static void free_all_channels(struct lightningd *ld)
{
	struct peer *p;

	/*~ tal supports *destructors* using `tal_add_destructor()`; the most
	 * common use is for an object to delete itself from a linked list
	 * when it's freed.
	 *
	 * As a result, freeing an object (which frees any tal objects
	 * allocated off it, and any allocated off them, etc) may cause
	 * callbacks; in this case, some objects freed here can cause database
	 * writes, which must be inside a transaction. */
	db_begin_transaction(ld->wallet->db);

	/* Now we free all the HTLCs */
	free_htlcs(ld, NULL);

	/*~ For every peer, we free every channel.  On allocation the peer was
	 * given a destructor (`destroy_peer`) which removes itself from the
	 * list.  Thus we use list_top() not list_pop() here. */
	while ((p = list_top(&ld->peers, struct peer, list)) != NULL) {
		struct channel *c;

		/*~ A peer can have multiple channels; we only allow one to be
		 * open at any time, but we remember old ones for 100 blocks,
		 * after all the outputs we care about are spent. */
		while ((c = list_top(&p->channels, struct channel, list))
		       != NULL) {
			/* Removes itself from list as we free it */
			tal_free(c);
		}

		/* A peer may have a channel in the process of opening. */
		if (p->uncommitted_channel) {
			struct uncommitted_channel *uc = p->uncommitted_channel;

			/* Setting to NULL stops destroy_uncommitted_channel
			 * from trying to remove peer from db! */
			p->uncommitted_channel = NULL;
			tal_free(uc);
		}
		/* Removes itself from list as we free it */
		tal_free(p);
	}

	/*~ Commit the transaction.  Note that the db is actually
	 * single-threaded, so commits never fail and we don't need
	 * spin-and-retry logic everywhere. */
	db_commit_transaction(ld->wallet->db);
}

static void shutdown_global_subdaemons(struct lightningd *ld)
{