/* Authors: Karl MacMillan <kmacmillan@tresys.com>
 *          Frank Mayer <mayerf@tresys.com>
 *
 * Copyright (C) 2003 - 2004 Tresys Technology, LLC
 *    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, version 2.
 */

#ifndef _CONDITIONAL_H_
#define _CONDITIONAL_H_

#include "avtab.h"
#include "symtab.h"
#include "policydb.h"

#define COND_EXPR_MAXDEPTH 10

/*
 * A conditional expression is a list of operators and operands
 * in reverse polish notation.
 */
struct cond_expr {
#define COND_BOOL    1 /* plain bool */
#define COND_NOT    2 /* !bool */
#define COND_OR        3 /* bool || bool */
#define COND_AND    4 /* bool && bool */
#define COND_XOR    5 /* bool ^ bool */
#define COND_EQ        6 /* bool == bool */
#define COND_NEQ    7 /* bool != bool */
#define COND_LAST    COND_NEQ
    __u32 expr_type;
    __u32 bool_val;
    struct cond_expr *next;
};

/*
 * Each cond_node contains a list of rules to be enabled/disabled
 * depending on the current value of the conditional expression. This
 * struct is for that list.
 */
struct cond_av_list {
    struct avtab_node *node;
    struct cond_av_list *next;
};

/*
 * A cond node represents a conditional block in a policy. It
 * contains a conditional expression, the current state of the expression,
 * two lists of rules to enable/disable depending on the value of the
 * expression (the true list corresponds to if and the false list corresponds
 * to else)..
 */
struct cond_node {
    int cur_state;
    struct cond_expr *expr;
    struct cond_av_list *true_list;
    struct cond_av_list *false_list;
    struct cond_node *next;
};

int cond_policydb_init(struct policydb* p);
void cond_policydb_destroy(struct policydb* p);

int cond_init_bool_indexes(struct policydb* p);
int cond_destroy_bool(void *key, void *datum, void *p);

int cond_index_bool(void *key, void *datum, void *datap);

int cond_read_bool(struct policydb *p, struct hashtab *h, void *fp);
int cond_read_list(struct policydb *p, void *fp);

void cond_compute_av(struct avtab *ctab, struct avtab_key *key, struct av_decision *avd);

int evaluate_cond_node(struct policydb *p, struct cond_node *node);

#endif /* _CONDITIONAL_H_ */
