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 21 #ifdef __cplusplus 22 extern "C" { 23 #endif 24 25 typedef char *hashtab_key_t; /* generic key type */ 26 typedef const char *const_hashtab_key_t; /* constant generic key type */ 27 typedef void *hashtab_datum_t; /* generic datum type */ 28 29 typedef struct hashtab_node *hashtab_ptr_t; 30 31 typedef struct hashtab_node { 32 hashtab_key_t key; 33 hashtab_datum_t datum; 34 hashtab_ptr_t next; 35 } hashtab_node_t; 36 37 typedef struct hashtab_val { 38 hashtab_ptr_t *htable; /* hash table */ 39 unsigned int size; /* number of slots in hash table */ 40 uint32_t nel; /* number of elements in hash table */ 41 unsigned int (*hash_value) (struct hashtab_val * h, const_hashtab_key_t key); /* hash function */ 42 int (*keycmp) (struct hashtab_val * h, const_hashtab_key_t key1, const_hashtab_key_t key2); /* key comparison function */ 43 } hashtab_val_t; 44 45 typedef hashtab_val_t *hashtab_t; 46 47 /* 48 Creates a new hash table with the specified characteristics. 49 50 Returns NULL if insufficent space is available or 51 the new hash table otherwise. 52 */ 53 extern hashtab_t hashtab_create(unsigned int (*hash_value) (hashtab_t h, 54 const_hashtab_key_t 55 key), 56 int (*keycmp) (hashtab_t h, 57 const_hashtab_key_t key1, 58 const_hashtab_key_t key2), 59 unsigned int size); 60 /* 61 Inserts the specified (key, datum) pair into the specified hash table. 62 63 Returns SEPOL_ENOMEM if insufficient space is available or 64 SEPOL_EEXIST if there is already an entry with the same key or 65 SEPOL_OK otherwise. 66 */ 67 extern int hashtab_insert(hashtab_t h, hashtab_key_t k, hashtab_datum_t d); 68 69 /* 70 Removes the entry with the specified key from the hash table. 71 Applies the specified destroy function to (key,datum,args) for 72 the entry. 73 74 Returns SEPOL_ENOENT if no entry has the specified key or 75 SEPOL_OK otherwise. 76 */ 77 extern int hashtab_remove(hashtab_t h, hashtab_key_t k, 78 void (*destroy) (hashtab_key_t k, 79 hashtab_datum_t d, 80 void *args), void *args); 81 82 /* 83 Insert or replace the specified (key, datum) pair in the specified 84 hash table. If an entry for the specified key already exists, 85 then the specified destroy function is applied to (key,datum,args) 86 for the entry prior to replacing the entry's contents. 87 88 Returns SEPOL_ENOMEM if insufficient space is available or 89 SEPOL_OK otherwise. 90 */ 91 extern int hashtab_replace(hashtab_t h, hashtab_key_t k, hashtab_datum_t d, 92 void (*destroy) (hashtab_key_t k, 93 hashtab_datum_t d, 94 void *args), void *args); 95 96 /* 97 Searches for the entry with the specified key in the hash table. 98 99 Returns NULL if no entry has the specified key or 100 the datum of the entry otherwise. 101 */ 102 extern hashtab_datum_t hashtab_search(hashtab_t h, const_hashtab_key_t k); 103 104 /* 105 Destroys the specified hash table. 106 */ 107 extern void hashtab_destroy(hashtab_t h); 108 109 /* 110 Applies the specified apply function to (key,datum,args) 111 for each entry in the specified hash table. 112 113 The order in which the function is applied to the entries 114 is dependent upon the internal structure of the hash table. 115 116 If apply returns a non-zero status, then hashtab_map will cease 117 iterating through the hash table and will propagate the error 118 return to its caller. 119 */ 120 extern int hashtab_map(hashtab_t h, 121 int (*apply) (hashtab_key_t k, 122 hashtab_datum_t d, 123 void *args), void *args); 124 125 /* 126 Same as hashtab_map, except that if apply returns a non-zero status, 127 then the (key,datum) pair will be removed from the hashtab and the 128 destroy function will be applied to (key,datum,args). 129 */ 130 extern void hashtab_map_remove_on_error(hashtab_t h, 131 int (*apply) (hashtab_key_t k, 132 hashtab_datum_t d, 133 void *args), 134 void (*destroy) (hashtab_key_t k, 135 hashtab_datum_t d, 136 void *args), 137 void *args); 138 139 extern void hashtab_hash_eval(hashtab_t h, char *tag); 140 141 #ifdef __cplusplus 142 } 143 #endif 144 145 #endif 146