ldb_map_outbound.c

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	}

	return 0;
}

/* Collect subtrees that query attributes in the remote partition */
static int map_subtree_collect_remote(struct ldb_module *module, void *mem_ctx, struct ldb_parse_tree **new, const struct ldb_parse_tree *tree)
{
	const struct ldb_map_context *data = map_get_context(module);
	const struct ldb_map_attribute *map;

	if (tree == NULL) {
		return 0;
	}

	if (tree->operation == LDB_OP_NOT) {
		return map_subtree_collect_remote_not(module, mem_ctx, new, tree);
	}

	if ((tree->operation == LDB_OP_AND) || (tree->operation == LDB_OP_OR)) {
		return map_subtree_collect_remote_list(module, mem_ctx, new, tree);
	}

	if (!map_attr_check_remote(data, tree->u.equality.attr)) {
		*new = NULL;
		return 0;
	}

	map = map_attr_find_local(data, tree->u.equality.attr);
	if (map->convert_operator) {
		return map->convert_operator(module, mem_ctx, new, tree);
	}

	if (map->type == MAP_GENERATE) {
		ldb_debug(module->ldb, LDB_DEBUG_WARNING, "ldb_map: "
			  "Skipping attribute '%s': "
			  "'convert_operator' not set\n",
			  tree->u.equality.attr);
		*new = NULL;
		return 0;
	}

	return map_subtree_collect_remote_simple(module, mem_ctx, new, tree, map);
}

/* Split subtrees that query attributes in the local partition from
 * those that query the remote partition. */
static int ldb_parse_tree_partition(struct ldb_module *module, void *local_ctx, void *remote_ctx, struct ldb_parse_tree **local_tree, struct ldb_parse_tree **remote_tree, const struct ldb_parse_tree *tree)
{
	int ret;

	*local_tree = NULL;
	*remote_tree = NULL;

	/* No original tree */
	if (tree == NULL) {
		return 0;
	}

	/* Generate local tree */
	ret = map_subtree_select_local(module, local_ctx, local_tree, tree);
	if (ret) {
		return ret;
	}

	/* Generate remote tree */
	ret = map_subtree_collect_remote(module, remote_ctx, remote_tree, tree);
	if (ret) {
		talloc_free(*local_tree);
		return ret;
	}

	return 0;
}

/* Collect a list of attributes required either explicitly from a
 * given list or implicitly  from a given parse tree; split the
 * collected list into local and remote parts. */
static int map_attrs_collect_and_partition(struct ldb_module *module, struct map_context *ac,
					   const char * const *search_attrs, 
					   const struct ldb_parse_tree *tree)
{
	void *tmp_ctx;
	const char **tree_attrs;
	const char **remote_attrs;
	const char **local_attrs;
	int ret;

	/* There is no tree, just partition the searched attributes */
	if (tree == NULL) {
		ret = map_attrs_partition(module, ac, 
					  &local_attrs, &remote_attrs, search_attrs);
		if (ret == 0) {
			ac->local_attrs = local_attrs;
			ac->remote_attrs = remote_attrs;
			ac->all_attrs = search_attrs;
		}
		return ret; 
	}

	/* Create context for temporary memory */
	tmp_ctx = talloc_new(ac);
	if (tmp_ctx == NULL) {
		goto oom;
	}

	/* Prepare list of attributes from tree */
	tree_attrs = talloc_array(tmp_ctx, const char *, 1);
	if (tree_attrs == NULL) {
		talloc_free(tmp_ctx);
		goto oom;
	}
	tree_attrs[0] = NULL;

	/* Collect attributes from tree */
	ret = ldb_parse_tree_collect_attrs(module, tmp_ctx, &tree_attrs, tree);
	if (ret) {
		goto done;
	}

	/* Merge attributes from search operation */
	ret = map_attrs_merge(module, tmp_ctx, &tree_attrs, search_attrs);
	if (ret) {
		goto done;
	}

	/* Split local from remote attributes */
	ret = map_attrs_partition(module, ac, &local_attrs, 
				  &remote_attrs, tree_attrs);
	
	if (ret == 0) {
		ac->local_attrs = local_attrs;
		ac->remote_attrs = remote_attrs;
		talloc_steal(ac, tree_attrs);
		ac->all_attrs = tree_attrs;
	}
done:
	/* Free temporary memory */
	talloc_free(tmp_ctx);
	return ret;

oom:
	map_oom(module);
	return -1;
}


/* Outbound requests: search
 * ========================= */

/* Pass a merged search result up the callback chain. */
int map_up_callback(struct ldb_context *ldb, const struct ldb_request *req, struct ldb_reply *ares)
{
	int i;

	/* No callback registered, stop */
	if (req->callback == NULL) {
		return LDB_SUCCESS;
	}

	/* Only records need special treatment */
	if (ares->type != LDB_REPLY_ENTRY) {
		return req->callback(ldb, req->context, ares);
	}

	/* Merged result doesn't match original query, skip */
	if (!ldb_match_msg(ldb, ares->message, req->op.search.tree, req->op.search.base, req->op.search.scope)) {
		ldb_debug(ldb, LDB_DEBUG_TRACE, "ldb_map: "
			  "Skipping record '%s': "
			  "doesn't match original search\n",
			  ldb_dn_get_linearized(ares->message->dn));
		return LDB_SUCCESS;
	}

	/* Limit result to requested attrs */
	if ((req->op.search.attrs) && (!ldb_attr_in_list(req->op.search.attrs, "*"))) {
		for (i = 0; i < ares->message->num_elements; ) {
			struct ldb_message_element *el = &ares->message->elements[i];
			if (!ldb_attr_in_list(req->op.search.attrs, el->name)) {
				ldb_msg_remove_element(ares->message, el);
			} else {
				i++;
			}
		}
	}

	return req->callback(ldb, req->context, ares);
}

/* Merge the remote and local parts of a search result. */
int map_local_merge_callback(struct ldb_context *ldb, void *context, struct ldb_reply *ares)
{
	struct map_search_context *sc;
	int ret;

	if (context == NULL || ares == NULL) {
		ldb_set_errstring(ldb, talloc_asprintf(ldb, "ldb_map: "
						       "NULL Context or Result in `map_local_merge_callback`"));
		return LDB_ERR_OPERATIONS_ERROR;
	}

	sc = talloc_get_type(context, struct map_search_context);

	switch (ares->type) {
	case LDB_REPLY_ENTRY:
		/* We have already found a local record */
		if (sc->local_res) {
			ldb_set_errstring(ldb, talloc_asprintf(ldb, "ldb_map: "
							       "Too many results to base search for local entry"));
			talloc_free(ares);
			return LDB_ERR_OPERATIONS_ERROR;
		}

		/* Store local result */
		sc->local_res = ares;

		/* Merge remote into local message */
		ret = ldb_msg_merge_local(sc->ac->module, ares->message, sc->remote_res->message);
		if (ret) {
			talloc_free(ares);
			return LDB_ERR_OPERATIONS_ERROR;
		}

		return map_up_callback(ldb, sc->ac->orig_req, ares);

	case LDB_REPLY_DONE:
		/* No local record found, continue with remote record */
		if (sc->local_res == NULL) {
			return map_up_callback(ldb, sc->ac->orig_req, sc->remote_res);
		}
		return LDB_SUCCESS;

	default:
		ldb_set_errstring(ldb, talloc_asprintf(ldb, "ldb_map: "
						       "Unexpected result type in base search for local entry"));
		talloc_free(ares);
		return LDB_ERR_OPERATIONS_ERROR;
	}
}

/* Search the local part of a remote search result. */
int map_remote_search_callback(struct ldb_context *ldb, void *context, struct ldb_reply *ares)
{
	struct map_context *ac;
	struct map_search_context *sc;
	struct ldb_request *req;
	int ret;

	if (context == NULL || ares == NULL) {
		ldb_set_errstring(ldb, talloc_asprintf(ldb, "ldb_map: "
						       "NULL Context or Result in `map_remote_search_callback`"));
		return LDB_ERR_OPERATIONS_ERROR;
	}

	ac = talloc_get_type(context, struct map_context);

	/* It's not a record, stop searching */
	if (ares->type != LDB_REPLY_ENTRY) {
		return map_up_callback(ldb, ac->orig_req, ares);
	}

	/* Map result record into a local message */
	ret = map_reply_remote(ac, ares);
	if (ret) {
		talloc_free(ares);
		return LDB_ERR_OPERATIONS_ERROR;
	}

	/* There is no local db, stop searching */
	if (!map_check_local_db(ac->module)) {
		return map_up_callback(ldb, ac->orig_req, ares);
	}

	/* Prepare local search context */
	sc = map_init_search_context(ac, ares);
	if (sc == NULL) {
		talloc_free(ares);
		return LDB_ERR_OPERATIONS_ERROR;
	}

	/* Prepare local search request */
	/* TODO: use GUIDs here instead? */

	ac->search_reqs = talloc_realloc(ac, ac->search_reqs, struct ldb_request *, ac->num_searches + 2);
	if (ac->search_reqs == NULL) {
		talloc_free(ares);
		return LDB_ERR_OPERATIONS_ERROR;
	}

	ac->search_reqs[ac->num_searches]
		= req = map_search_base_req(ac, ares->message->dn, 
					    NULL, NULL, sc, map_local_merge_callback);
	if (req == NULL) {
		talloc_free(sc);
		talloc_free(ares);
		return LDB_ERR_OPERATIONS_ERROR;
	}
	ac->num_searches++;
	ac->search_reqs[ac->num_searches] = NULL;

	return ldb_next_request(ac->module, req);
}

/* Search a record. */
int map_search(struct ldb_module *module, struct ldb_request *req)
{
	struct ldb_handle *h;
	struct map_context *ac;
	struct ldb_parse_tree *local_tree, *remote_tree;
	int ret;

	const char *wildcard[] = { "*", NULL };
	const char * const *attrs;

	if (!module->private_data) /* if we're not yet initialized, go to the next module */
		return ldb_next_request(module, req);

	/* Do not manipulate our control entries */
	if (ldb_dn_is_special(req->op.search.base))
		return ldb_next_request(module, req);

	/* No mapping requested, skip to next module */
	if ((req->op.search.base) && (!ldb_dn_check_local(module, req->op.search.base))) {
		return ldb_next_request(module, req);
	}

	/* TODO: How can we be sure about which partition we are
	 *	 targetting when there is no search base? */

	/* Prepare context and handle */
	h = map_init_handle(req, module);
	if (h == NULL) {
		return LDB_ERR_OPERATIONS_ERROR;
	}
	ac = talloc_get_type(h->private_data, struct map_context);

	ac->search_reqs = talloc_array(ac, struct ldb_request *, 2);
	if (ac->search_reqs == NULL) {
		talloc_free(h);
		return LDB_ERR_OPERATIONS_ERROR;
	}
	ac->num_searches = 1;
	ac->search_reqs[1] = NULL;

	/* Prepare the remote operation */
	ac->search_reqs[0] = talloc(ac, struct ldb_request);
	if (ac->search_reqs[0] == NULL) {
		goto oom;
	}

	*(ac->search_reqs[0]) = *req;	/* copy the request */

	ac->search_reqs[0]->handle = h;	/* return our own handle to deal with this call */

	ac->search_reqs[0]->context = ac;
	ac->search_reqs[0]->callback = map_remote_search_callback;

	/* It is easier to deal with the two different ways of
	 * expressing the wildcard in the same codepath */
	attrs = req->op.search.attrs;
	if (attrs == NULL) {
		attrs = wildcard;
	}

	/* Split local from remote attrs */
	ret = map_attrs_collect_and_partition(module, ac, 
					      attrs, req->op.search.tree);
	if (ret) {
		goto failed;
	}

	ac->search_reqs[0]->op.search.attrs = ac->remote_attrs;

	/* Split local from remote tree */
	ret = ldb_parse_tree_partition(module, ac, ac->search_reqs[0], 
				       &local_tree, &remote_tree, 
				       req->op.search.tree);
	if (ret) {
		goto failed;
	}

	if (((local_tree != NULL) && (remote_tree != NULL)) &&
	    (!ldb_parse_tree_check_splittable(req->op.search.tree))) {
		/* The query can't safely be split, enumerate the remote partition */
		local_tree = NULL;
		remote_tree = NULL;
	}

	if (local_tree == NULL) {
		/* Construct default local parse tree */
		local_tree = talloc_zero(ac, struct ldb_parse_tree);
		if (local_tree == NULL) {
			map_oom(ac->module);
			goto failed;
		}

		local_tree->operation = LDB_OP_PRESENT;
		local_tree->u.present.attr = talloc_strdup(local_tree, IS_MAPPED);
	}
	if (remote_tree == NULL) {
		/* Construct default remote parse tree */
		remote_tree = ldb_parse_tree(ac->search_reqs[0], NULL);
		if (remote_tree == NULL) {
			goto failed;
		}
	}

	ac->local_tree = local_tree;
	ac->search_reqs[0]->op.search.tree = remote_tree;

	ldb_set_timeout_from_prev_req(module->ldb, req, ac->search_reqs[0]);

	h->state = LDB_ASYNC_INIT;
	h->status = LDB_SUCCESS;

	ac->step = MAP_SEARCH_REMOTE;

	ret = ldb_next_remote_request(module, ac->search_reqs[0]);
	if (ret == LDB_SUCCESS) {
		req->handle = h;
	}
	return ret;

oom:
	map_oom(module);
failed:
	talloc_free(h);
	return LDB_ERR_OPERATIONS_ERROR;
}