1/* Author : Stephen Smalley, <sds@epoch.ncsc.mil> */
2
3/* FLASK */
4
5/*
6 * A hash table (hashtab) maintains associations between
7 * key values and datum values.  The type of the key values
8 * and the type of the datum values is arbitrary.  The
9 * functions for hash computation and key comparison are
10 * provided by the creator of the table.
11 */
12
13#ifndef _SEPOL_POLICYDB_HASHTAB_H_
14#define _SEPOL_POLICYDB_HASHTAB_H_
15
16#include <sepol/errcodes.h>
17
18#include <stdint.h>
19#include <stdio.h>
20#include <sys/cdefs.h>
21
22__BEGIN_DECLS
23
24typedef char *hashtab_key_t;	/* generic key type */
25typedef void *hashtab_datum_t;	/* generic datum type */
26
27typedef struct hashtab_node *hashtab_ptr_t;
28
29typedef struct hashtab_node {
30	hashtab_key_t key;
31	hashtab_datum_t datum;
32	hashtab_ptr_t next;
33} hashtab_node_t;
34
35typedef struct hashtab_val {
36	hashtab_ptr_t *htable;	/* hash table */
37	unsigned int size;	/* number of slots in hash table */
38	uint32_t nel;		/* number of elements in hash table */
39	unsigned int (*hash_value) (struct hashtab_val * h, hashtab_key_t key);	/* hash function */
40	int (*keycmp) (struct hashtab_val * h, hashtab_key_t key1, hashtab_key_t key2);	/* key comparison function */
41} hashtab_val_t;
42
43typedef hashtab_val_t *hashtab_t;
44
45/*
46   Creates a new hash table with the specified characteristics.
47
48   Returns NULL if insufficent space is available or
49   the new hash table otherwise.
50 */
51extern hashtab_t hashtab_create(unsigned int (*hash_value) (hashtab_t h,
52							    const hashtab_key_t
53							    key),
54				int (*keycmp) (hashtab_t h,
55					       const hashtab_key_t key1,
56					       const hashtab_key_t key2),
57				unsigned int size);
58/*
59   Inserts the specified (key, datum) pair into the specified hash table.
60
61   Returns SEPOL_ENOMEM if insufficient space is available or
62   SEPOL_EEXIST  if there is already an entry with the same key or
63   SEPOL_OK otherwise.
64 */
65extern int hashtab_insert(hashtab_t h, hashtab_key_t k, hashtab_datum_t d);
66
67/*
68   Removes the entry with the specified key from the hash table.
69   Applies the specified destroy function to (key,datum,args) for
70   the entry.
71
72   Returns SEPOL_ENOENT if no entry has the specified key or
73   SEPOL_OK otherwise.
74 */
75extern int hashtab_remove(hashtab_t h, hashtab_key_t k,
76			  void (*destroy) (hashtab_key_t k,
77					   hashtab_datum_t d,
78					   void *args), void *args);
79
80/*
81   Insert or replace the specified (key, datum) pair in the specified
82   hash table.  If an entry for the specified key already exists,
83   then the specified destroy function is applied to (key,datum,args)
84   for the entry prior to replacing the entry's contents.
85
86   Returns SEPOL_ENOMEM if insufficient space is available or
87   SEPOL_OK otherwise.
88 */
89extern int hashtab_replace(hashtab_t h, hashtab_key_t k, hashtab_datum_t d,
90			   void (*destroy) (hashtab_key_t k,
91					    hashtab_datum_t d,
92					    void *args), void *args);
93
94/*
95   Searches for the entry with the specified key in the hash table.
96
97   Returns NULL if no entry has the specified key or
98   the datum of the entry otherwise.
99 */
100extern hashtab_datum_t hashtab_search(hashtab_t h, const hashtab_key_t k);
101
102/*
103   Destroys the specified hash table.
104 */
105extern void hashtab_destroy(hashtab_t h);
106
107/*
108   Applies the specified apply function to (key,datum,args)
109   for each entry in the specified hash table.
110
111   The order in which the function is applied to the entries
112   is dependent upon the internal structure of the hash table.
113
114   If apply returns a non-zero status, then hashtab_map will cease
115   iterating through the hash table and will propagate the error
116   return to its caller.
117 */
118extern int hashtab_map(hashtab_t h,
119		       int (*apply) (hashtab_key_t k,
120				     hashtab_datum_t d,
121				     void *args), void *args);
122
123/*
124   Same as hashtab_map, except that if apply returns a non-zero status,
125   then the (key,datum) pair will be removed from the hashtab and the
126   destroy function will be applied to (key,datum,args).
127 */
128extern void hashtab_map_remove_on_error(hashtab_t h,
129					int (*apply) (hashtab_key_t k,
130						      hashtab_datum_t d,
131						      void *args),
132					void (*destroy) (hashtab_key_t k,
133							 hashtab_datum_t d,
134							 void *args),
135					void *args);
136
137extern void hashtab_hash_eval(hashtab_t h, char *tag);
138
139__END_DECLS
140#endif
141