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Diffstat (limited to 'include/sepol/policydb/hashtab.h')
| -rw-r--r-- | include/sepol/policydb/hashtab.h | 137 |
1 files changed, 137 insertions, 0 deletions
diff --git a/include/sepol/policydb/hashtab.h b/include/sepol/policydb/hashtab.h new file mode 100644 index 0000000..1081ff6 --- /dev/null +++ b/include/sepol/policydb/hashtab.h @@ -0,0 +1,137 @@ + +/* Author : Stephen Smalley, <sds@epoch.ncsc.mil> */ + +/* FLASK */ + +/* + * A hash table (hashtab) maintains associations between + * key values and datum values. The type of the key values + * and the type of the datum values is arbitrary. The + * functions for hash computation and key comparison are + * provided by the creator of the table. + */ + +#ifndef _SEPOL_POLICYDB_HASHTAB_H_ +#define _SEPOL_POLICYDB_HASHTAB_H_ + +#include <sepol/errcodes.h> + +#include <stdint.h> +#include <stdio.h> + +typedef char *hashtab_key_t; /* generic key type */ +typedef void *hashtab_datum_t; /* generic datum type */ + +typedef struct hashtab_node *hashtab_ptr_t; + +typedef struct hashtab_node { + hashtab_key_t key; + hashtab_datum_t datum; + hashtab_ptr_t next; +} hashtab_node_t; + +typedef struct hashtab_val { + hashtab_ptr_t *htable; /* hash table */ + unsigned int size; /* number of slots in hash table */ + uint32_t nel; /* number of elements in hash table */ + unsigned int (*hash_value) (struct hashtab_val * h, hashtab_key_t key); /* hash function */ + int (*keycmp) (struct hashtab_val * h, hashtab_key_t key1, hashtab_key_t key2); /* key comparison function */ +} hashtab_val_t; + +typedef hashtab_val_t *hashtab_t; + +/* + Creates a new hash table with the specified characteristics. + + Returns NULL if insufficent space is available or + the new hash table otherwise. + */ +extern hashtab_t hashtab_create(unsigned int (*hash_value) (hashtab_t h, + const hashtab_key_t + key), + int (*keycmp) (hashtab_t h, + const hashtab_key_t key1, + const hashtab_key_t key2), + unsigned int size); +/* + Inserts the specified (key, datum) pair into the specified hash table. + + Returns SEPOL_ENOMEM if insufficient space is available or + SEPOL_EEXIST if there is already an entry with the same key or + SEPOL_OK otherwise. + */ +extern int hashtab_insert(hashtab_t h, hashtab_key_t k, hashtab_datum_t d); + +/* + Removes the entry with the specified key from the hash table. + Applies the specified destroy function to (key,datum,args) for + the entry. + + Returns SEPOL_ENOENT if no entry has the specified key or + SEPOL_OK otherwise. + */ +extern int hashtab_remove(hashtab_t h, hashtab_key_t k, + void (*destroy) (hashtab_key_t k, + hashtab_datum_t d, + void *args), void *args); + +/* + Insert or replace the specified (key, datum) pair in the specified + hash table. If an entry for the specified key already exists, + then the specified destroy function is applied to (key,datum,args) + for the entry prior to replacing the entry's contents. + + Returns SEPOL_ENOMEM if insufficient space is available or + SEPOL_OK otherwise. + */ +extern int hashtab_replace(hashtab_t h, hashtab_key_t k, hashtab_datum_t d, + void (*destroy) (hashtab_key_t k, + hashtab_datum_t d, + void *args), void *args); + +/* + Searches for the entry with the specified key in the hash table. + + Returns NULL if no entry has the specified key or + the datum of the entry otherwise. + */ +extern hashtab_datum_t hashtab_search(hashtab_t h, const hashtab_key_t k); + +/* + Destroys the specified hash table. + */ +extern void hashtab_destroy(hashtab_t h); + +/* + Applies the specified apply function to (key,datum,args) + for each entry in the specified hash table. + + The order in which the function is applied to the entries + is dependent upon the internal structure of the hash table. + + If apply returns a non-zero status, then hashtab_map will cease + iterating through the hash table and will propagate the error + return to its caller. + */ +extern int hashtab_map(hashtab_t h, + int (*apply) (hashtab_key_t k, + hashtab_datum_t d, + void *args), void *args); + +/* + Same as hashtab_map, except that if apply returns a non-zero status, + then the (key,datum) pair will be removed from the hashtab and the + destroy function will be applied to (key,datum,args). + */ +extern void hashtab_map_remove_on_error(hashtab_t h, + int (*apply) (hashtab_key_t k, + hashtab_datum_t d, + void *args), + void (*destroy) (hashtab_key_t k, + hashtab_datum_t d, + void *args), + void *args); + +extern void hashtab_hash_eval(hashtab_t h, char *tag); + +#endif |