Function gossmap_compact

gossipd/gossmap_manage.c:1759–1852

Returns false if already running */

}
/* Returns false if already running */
static bool gossmap_compact(struct gossmap_manage *gm, bool dev_compact)
{
	int childin[2], execfail[2], childout[2];
	int saved_errno;

	/* Only one at a time please! */
	if (gm->compactd)
		return false;

	/* This checks contents: we want to make sure compactd sees an
	 * up-to-date version. */
	gossmap_manage_get_gossmap(gm);

	gm->compactd = tal(gm, struct compactd);
	for (size_t i = 0; i < ARRAY_SIZE(gm->compactd->uuid); i++)
		gm->compactd->uuid[i] = pseudorand(256);

	gm->compactd->old_size = gossip_store_len_written(gm->gs);
	status_debug("Executing lightning_gossip_compactd %s %s %s %s",
		     GOSSIP_STORE_FILENAME,
		     GOSSIP_STORE_COMPACT_FILENAME,
		     tal_fmt(tmpctx, "%"PRIu64, gm->compactd->old_size),
		     tal_hexstr(tmpctx, gm->compactd->uuid, sizeof(gm->compactd->uuid)));

	if (pipe(childin) != 0 || pipe(childout) != 0 || pipe(execfail) != 0)
		status_failed(STATUS_FAIL_INTERNAL_ERROR,
			      "Could not create pipes for compactd: %s",
			      strerror(errno));

	if (fcntl(execfail[1], F_SETFD, fcntl(execfail[1], F_GETFD)
		  | FD_CLOEXEC) < 0)
		status_failed(STATUS_FAIL_INTERNAL_ERROR,
			      "Could not set cloexec on compactd fd: %s",
			      strerror(errno));

	gm->compactd->pid = fork();
	if (gm->compactd->pid < 0)
		status_failed(STATUS_FAIL_INTERNAL_ERROR,
			      "Could not fork for compactd: %s",
			      strerror(errno));

	if (gm->compactd->pid == 0) {
		close(childin[0]);
		close(childout[1]);
		close(execfail[0]);

		/* In practice, low fds are all open, so we don't have
		 * to handle those horrible cases */
		assert(childin[1] > 2);
		assert(childout[0] > 2);
		if (dup2(childin[1], STDOUT_FILENO) == -1)
			err(1, "Failed to duplicate fd to stdout");
		close(childin[1]);
		if (dup2(childout[0], STDIN_FILENO) == -1)
			err(1, "Failed to duplicate fd to stdin");
		close(childout[0]);
		closefrom_limit(0);
		closefrom(3);