bb24249747
Makes the key argument passed into hashtab_search and all the functions it calls constant. These functions include hash table function pointers hash_value and keycmp. The only implementations of these currently are symhash and symcmp, which do not modify the key. The key parameter should never be changed by any of these, so it should be const. This is necessary to allow calling these functions with keys found in kernel object class and permission definitions. Signed-off-by: Chad Sellers <csellers@tresys.com> Acked-by: Stephen Smalley <sds@tycho.nsa.gov> Signed-off-by: James Morris <jmorris@namei.org>
87 lines
2.5 KiB
C
87 lines
2.5 KiB
C
/*
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* A hash table (hashtab) maintains associations between
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* key values and datum values. The type of the key values
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* and the type of the datum values is arbitrary. The
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* functions for hash computation and key comparison are
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* provided by the creator of the table.
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*
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* Author : Stephen Smalley, <sds@epoch.ncsc.mil>
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*/
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#ifndef _SS_HASHTAB_H_
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#define _SS_HASHTAB_H_
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#define HASHTAB_MAX_NODES 0xffffffff
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struct hashtab_node {
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void *key;
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void *datum;
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struct hashtab_node *next;
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};
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struct hashtab {
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struct hashtab_node **htable; /* hash table */
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u32 size; /* number of slots in hash table */
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u32 nel; /* number of elements in hash table */
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u32 (*hash_value)(struct hashtab *h, const void *key);
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/* hash function */
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int (*keycmp)(struct hashtab *h, const void *key1, const void *key2);
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/* key comparison function */
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};
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struct hashtab_info {
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u32 slots_used;
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u32 max_chain_len;
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};
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/*
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* Creates a new hash table with the specified characteristics.
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*
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* Returns NULL if insufficent space is available or
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* the new hash table otherwise.
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*/
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struct hashtab *hashtab_create(u32 (*hash_value)(struct hashtab *h, const void *key),
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int (*keycmp)(struct hashtab *h, const void *key1, const void *key2),
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u32 size);
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/*
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* Inserts the specified (key, datum) pair into the specified hash table.
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*
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* Returns -ENOMEM on memory allocation error,
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* -EEXIST if there is already an entry with the same key,
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* -EINVAL for general errors or
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* 0 otherwise.
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*/
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int hashtab_insert(struct hashtab *h, void *k, void *d);
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/*
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* Searches for the entry with the specified key in the hash table.
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*
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* Returns NULL if no entry has the specified key or
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* the datum of the entry otherwise.
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*/
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void *hashtab_search(struct hashtab *h, const void *k);
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/*
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* Destroys the specified hash table.
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*/
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void hashtab_destroy(struct hashtab *h);
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/*
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* Applies the specified apply function to (key,datum,args)
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* for each entry in the specified hash table.
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*
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* The order in which the function is applied to the entries
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* is dependent upon the internal structure of the hash table.
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*
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* If apply returns a non-zero status, then hashtab_map will cease
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* iterating through the hash table and will propagate the error
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* return to its caller.
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*/
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int hashtab_map(struct hashtab *h,
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int (*apply)(void *k, void *d, void *args),
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void *args);
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/* Fill info with some hash table statistics */
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void hashtab_stat(struct hashtab *h, struct hashtab_info *info);
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#endif /* _SS_HASHTAB_H */
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