/* 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	8
  	__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_ */