1 2 /* Author : Stephen Smalley, <sds (at) 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 22 typedef char *hashtab_key_t; /* generic key type */ 23 typedef void *hashtab_datum_t; /* generic datum type */ 24 25 typedef struct hashtab_node *hashtab_ptr_t; 26 27 typedef struct hashtab_node { 28 hashtab_key_t key; 29 hashtab_datum_t datum; 30 hashtab_ptr_t next; 31 } hashtab_node_t; 32 33 typedef 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 41 typedef 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 */ 49 extern 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 */ 63 extern 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 */ 73 extern 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 */ 87 extern 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 */ 98 extern hashtab_datum_t hashtab_search(hashtab_t h, const hashtab_key_t k); 99 100 /* 101 Destroys the specified hash table. 102 */ 103 extern 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 */ 116 extern 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 */ 126 extern 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); 134 135 extern void hashtab_hash_eval(hashtab_t h, char *tag); 136 137 #endif 138
