/*
   Unix SMB/CIFS implementation.

   security access checking routines

   Copyright (C) Nadezhda Ivanova 2009

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

/*
 *  Description: Contains data handler functions for
 *               the object tree that must be constructed to perform access checks.
 *               The object tree is an unbalanced tree of depth 3, indexed by
 *               object type guid. Perhaps a different data structure
 *               should be concidered later to improve performance
 *
 *  Author: Nadezhda Ivanova
 */
#include "includes.h"
#include "libcli/security/security.h"
#include "librpc/ndr/libndr.h"

/* Adds a new node to the object tree. If attributeSecurityGUID is not zero and
 * has already been added to the tree, the new node is added as a child of that node
 * In all other cases as a child of the root
 */

bool insert_in_object_tree(TALLOC_CTX *mem_ctx,
			   const struct GUID *guid,
			   uint32_t init_access,
			   struct object_tree *root,
			   struct object_tree **new_node_out)
{
	struct object_tree *new_node;

	if (!guid || GUID_all_zero(guid)){
		return true;
	}

	if (!root) {
		root = talloc_zero(mem_ctx, struct object_tree);
		if (!root) {
			return false;
		}
		new_node = root;
	} else {
		int i;

		for (i = 0; i < root->num_of_children; i++) {
			if (GUID_equal(&root->children[i].guid, guid)) {
				new_node = &root->children[i];
				new_node->remaining_access |= init_access;
				*new_node_out = new_node;
				return true;
			}
		}

		root->children = talloc_realloc(mem_ctx, root->children,
						struct object_tree,
						root->num_of_children + 1);
		if (!root->children) {
			return false;
		}
		new_node = &root->children[root->num_of_children];
		root->num_of_children++;
	}

	new_node->children = NULL;
	new_node->guid = *guid;
	new_node->remaining_access = init_access;
	new_node->num_of_children = 0;

	*new_node_out = new_node;
	return true;
}

/* search by GUID */
struct object_tree *get_object_tree_by_GUID(struct object_tree *root,
					     const struct GUID *guid)
{
	struct object_tree *result = NULL;
	int i;

	if (!root || GUID_equal(&root->guid, guid)) {
		result = root;
		return result;
	}
	for (i = 0; i < root->num_of_children; i++) {
		if ((result = get_object_tree_by_GUID(&root->children[i], guid)))
			break;
	}
	return result;
}

/**
 * @brief Modify the tree to mark specified access rights as granted
 *
 * This function will modify the root and the child of the tree pointed by
 * root, so that for each tree element the bits set in access_mask are
 * marked as granted.
 *
 * @param[in]  root        An object_tree structure that we want to modify
 *
 * @param[in]  access_mask A bitfield of access right that we want to mark as
 *                         granted in the whole tree.
 */
void object_tree_modify_access(struct object_tree *root,
			       uint32_t access_mask)
{
	int i;
	root->remaining_access &= ~access_mask;
	for (i = 0; i < root->num_of_children; i++) {
		object_tree_modify_access(&root->children[i], access_mask);
	}
}