Something

static pk_err_t obtain_chunk(struct pk_state *state, unsigned chunk,
			void *tag, void **buf, unsigned *len)
{
	pk_err_t ret;
	void *local_buf;
	gchar *device_buf;
	gchar *ftag;

	local_buf = g_malloc(state->parcel->chunksize);
	/* Read the chunk from the local cache.  Don't check the
	   tag, since decrypt will check the key.
	   length is not zero only when chunk is present in local cache */
	if (*len && !_cache_read_chunk(state, chunk, local_buf, *len, NULL)) {
		*buf = local_buf;
		return PK_SUCCESS;
	}

	/* Get chunk from hoard cache */
	if (!hoard_get_chunk(state, tag, local_buf, len)) {
		*buf = local_buf;
		return PK_SUCCESS;
	}
	ftag = iu_bin2hex(tag, state->parcel->hashlen);
	pk_log(LOG_CHUNK, "Tag %s not in hoard cache", ftag);
	g_free(ftag);

	/* Get chunk from horatio */
	if (!device_get_chunk(state, tag, state->parcel->hashlen, &device_buf,
				len)) {
		*buf = device_buf;
		g_free(local_buf);
		return PK_SUCCESS;
	}

	/* Get chunk from server */
	ret = transport_fetch_chunk(state->cpool, local_buf, chunk,
				tag, len, TRUE);
	*buf = local_buf;

	return ret;
}

pk_err_t device_get_chunk(struct pk_state *state, void *tag, unsigned taglen,
			gchar **buf, unsigned *filelen)
{
	pk_err_t ret;
	struct query *qry;
	gboolean retry;

	if (state->conf->device_path == NULL) {
		return PK_NOTFOUND;
	}

again:
	if (!begin(state->db)) {
		return PK_SQLERR;
	}

	if (!query(&qry, state->db, "SELECT id FROM horatio.chunks "
				"WHERE tag == ?", "b",
				tag, taglen)) {
		sql_log_err(state->db, "Error searching for chunk on device\n");
		ret = PK_SQLERR;
		goto bad;
	}

	if (query_has_row(state->db)) {
		ret = _device_read_chunk(state, tag, taglen, buf, filelen);
	} else {
		printf("Chunk not found on device\n");
		ret = PK_NOTFOUND;
	}

	query_free(qry);

	return ret;

bad:
	retry = query_busy(state->db);
	rollback(state->db);
	if (retry) {
		query_backoff(state->db);
		goto again;
	}
	return ret;
}