Function reopen_store

common/gossmap.c:732–797

}

static bool reopen_store(struct gossmap *map, u64 ended_off)
{
	u64 equivalent_off;
	u8 verbyte;
	u8 expected_uuid[32], uuid[32];
	struct gossip_hdr ghdr;
	bool changed;

	/* This tells us the equivalent offset in new map */
	equivalent_off = map_be64(map, ended_off + 2);
	map_copy(map, ended_off + 2 + 8, expected_uuid, sizeof(expected_uuid));
	close(map->fd);

	map->fd = open(map->fname, O_RDONLY);
	if (map->fd < 0)
		err(1, "Failed to reopen %s", map->fname);

	/* If mmap isn't disabled, we try to mmap if we can. */
	map->map_size = lseek(map->fd, 0, SEEK_END);
	if (map->mmap) {
		map->mmap = mmap(NULL, map->map_size, PROT_READ, MAP_SHARED, map->fd, 0);
		if (map->mmap == MAP_FAILED)
			map->mmap = NULL;
	}

	if (map->map_size < 1 + sizeof(ghdr) + 2 + sizeof(uuid))
		errx(1, "Truncated gossip_store len %"PRIu64, map->map_size);

	/* version then ghdr then uuid. */
	verbyte = map_u8(map, 0);
	if (GOSSIP_STORE_MAJOR_VERSION(verbyte) != 0 || GOSSIP_STORE_MINOR_VERSION(verbyte) < 16)
		errx(1, "Bad gossip_store version %u", verbyte);

	if (map_be16(map, 1 + sizeof(struct gossip_hdr)) != WIRE_GOSSIP_STORE_UUID)
		errx(1, "First gossip_store record is not uuid?");
	map_copy(map, 1 + sizeof(struct gossip_hdr) + 2, uuid, sizeof(uuid));

	/* FIXME: we can skip if uuid is as expected, but we'd have to re-calc all
	 * our offsets anyway.  It's not worth it, given how fast we are. */
	if (memcmp(uuid, expected_uuid, sizeof(uuid)) == 0) {
		map->logcb(map->cbarg, LOG_DBG,
			   "Reopened gossip_store, reduced to offset %"PRIu64,
			   equivalent_off);
	} else {
		/* Start from scratch */
		map->logcb(map->cbarg, LOG_INFORM,
			   "Reopened gossip_store, but we missed some (%s vs %s)",
			   tal_hexstr(tmpctx, uuid, sizeof(uuid)),
			   tal_hexstr(tmpctx, expected_uuid, sizeof(expected_uuid)));
	}

	tal_free(map->channels);
	tal_free(map->nodes);
	tal_free(map->chan_arr);
	tal_free(map->node_arr);
	init_map_structs(map);
	map->map_end = 1;
	map->generation++;