root/security/selinux/ss/conditional.h

INCLUDED FROM

/* 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;
        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_ */