1 /* Author : Stephen Smalley, <sds (at) 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 24 typedef char *hashtab_key_t; /* generic key type */ 25 typedef void *hashtab_datum_t; /* generic datum type */ 26 27 typedef struct hashtab_node *hashtab_ptr_t; 28 29 typedef struct hashtab_node { 30 hashtab_key_t key; 31 hashtab_datum_t datum; 32 hashtab_ptr_t next; 33 } hashtab_node_t; 34 35 typedef 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 43 typedef 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 */ 51 extern 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 */ 65 extern 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 */ 75 extern 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 */ 89 extern 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 */ 100 extern hashtab_datum_t hashtab_search(hashtab_t h, const hashtab_key_t k); 101 102 /* 103 Destroys the specified hash table. 104 */ 105 extern 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 */ 118 extern 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 */ 128 extern 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); 136 137 extern void hashtab_hash_eval(hashtab_t h, char *tag); 138 139 __END_DECLS 140 #endif 141
