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