Function transfer_store_msg

gossipd/gossip_store.c:313–367

Returns bytes transferred, or 0 on error */

/* Returns bytes transferred, or 0 on error */
static size_t transfer_store_msg(int from_fd, size_t from_off,
				 int to_fd, size_t to_off,
				 int *type)
{
	struct gossip_hdr hdr;
	u32 msglen;
	u8 *msg;
	const u8 *p;
	size_t tmplen;

	*type = -1;
	if (pread(from_fd, &hdr, sizeof(hdr), from_off) != sizeof(hdr)) {
		status_broken("Failed reading header from to gossip store @%zu"
			      ": %s",
			      from_off, strerror(errno));
		return 0;
	}

	msglen = be32_to_cpu(hdr.len);
	if (msglen & GOSSIP_STORE_LEN_DELETED_BIT) {
		status_broken("Can't transfer deleted msg from gossip store @%zu",
			      from_off);
		return 0;
	}

	/* Ignore any non-length bits (e.g. push) */
	msglen &= GOSSIP_STORE_LEN_MASK;

	/* FIXME: Reuse buffer? */
	msg = tal_arr(tmpctx, u8, sizeof(hdr) + msglen);
	memcpy(msg, &hdr, sizeof(hdr));
	if (pread(from_fd, msg + sizeof(hdr), msglen, from_off + sizeof(hdr))
	    != msglen) {
		status_broken("Failed reading %u from to gossip store @%zu"
			      ": %s",
			      msglen, from_off, strerror(errno));
		return 0;
	}

	if (pwrite(to_fd, msg, msglen + sizeof(hdr), to_off)
	    != msglen + sizeof(hdr)) {
		status_broken("Failed writing to gossip store: %s",
			      strerror(errno));
		return 0;
	}

	/* Can't use peektype here, since we have header on front */
	p = msg + sizeof(hdr);
	tmplen = msglen;
	*type = fromwire_u16(&p, &tmplen);
	if (!p)
		*type = -1;
	tal_free(msg);
	return sizeof(hdr) + msglen;
}

/* We keep a htable map of old gossip_store offsets to new ones. */
struct offset_map {