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- /*
- * Implementation of the hash table type.
- *
- * Author : Stephen Smalley, <sds@epoch.ncsc.mil>
- */
- #include <linux/kernel.h>
- #include <linux/slab.h>
- #include <linux/errno.h>
- #include <linux/sched.h>
- #include "hashtab.h"
- struct hashtab *hashtab_create(u32 (*hash_value)(struct hashtab *h, const void *key),
- int (*keycmp)(struct hashtab *h, const void *key1, const void *key2),
- u32 size)
- {
- struct hashtab *p;
- u32 i;
- p = kzalloc(sizeof(*p), GFP_KERNEL);
- if (p == NULL)
- return p;
- p->size = size;
- p->nel = 0;
- p->hash_value = hash_value;
- p->keycmp = keycmp;
- p->htable = kmalloc(sizeof(*(p->htable)) * size, GFP_KERNEL);
- if (p->htable == NULL) {
- kfree(p);
- return NULL;
- }
- for (i = 0; i < size; i++)
- p->htable[i] = NULL;
- return p;
- }
- int hashtab_insert(struct hashtab *h, void *key, void *datum)
- {
- u32 hvalue;
- struct hashtab_node *prev, *cur, *newnode;
- cond_resched();
- if (!h || h->nel == HASHTAB_MAX_NODES)
- return -EINVAL;
- hvalue = h->hash_value(h, key);
- prev = NULL;
- cur = h->htable[hvalue];
- while (cur && h->keycmp(h, key, cur->key) > 0) {
- prev = cur;
- cur = cur->next;
- }
- if (cur && (h->keycmp(h, key, cur->key) == 0))
- return -EEXIST;
- newnode = kzalloc(sizeof(*newnode), GFP_KERNEL);
- if (newnode == NULL)
- return -ENOMEM;
- newnode->key = key;
- newnode->datum = datum;
- if (prev) {
- newnode->next = prev->next;
- prev->next = newnode;
- } else {
- newnode->next = h->htable[hvalue];
- h->htable[hvalue] = newnode;
- }
- h->nel++;
- return 0;
- }
- void *hashtab_search(struct hashtab *h, const void *key)
- {
- u32 hvalue;
- struct hashtab_node *cur;
- if (!h)
- return NULL;
- hvalue = h->hash_value(h, key);
- cur = h->htable[hvalue];
- while (cur && h->keycmp(h, key, cur->key) > 0)
- cur = cur->next;
- if (cur == NULL || (h->keycmp(h, key, cur->key) != 0))
- return NULL;
- return cur->datum;
- }
- void hashtab_destroy(struct hashtab *h)
- {
- u32 i;
- struct hashtab_node *cur, *temp;
- if (!h)
- return;
- for (i = 0; i < h->size; i++) {
- cur = h->htable[i];
- while (cur) {
- temp = cur;
- cur = cur->next;
- kfree(temp);
- }
- h->htable[i] = NULL;
- }
- kfree(h->htable);
- h->htable = NULL;
- kfree(h);
- }
- int hashtab_map(struct hashtab *h,
- int (*apply)(void *k, void *d, void *args),
- void *args)
- {
- u32 i;
- int ret;
- struct hashtab_node *cur;
- if (!h)
- return 0;
- for (i = 0; i < h->size; i++) {
- cur = h->htable[i];
- while (cur) {
- ret = apply(cur->key, cur->datum, args);
- if (ret)
- return ret;
- cur = cur->next;
- }
- }
- return 0;
- }
- void hashtab_stat(struct hashtab *h, struct hashtab_info *info)
- {
- u32 i, chain_len, slots_used, max_chain_len;
- struct hashtab_node *cur;
- slots_used = 0;
- max_chain_len = 0;
- for (slots_used = max_chain_len = i = 0; i < h->size; i++) {
- cur = h->htable[i];
- if (cur) {
- slots_used++;
- chain_len = 0;
- while (cur) {
- chain_len++;
- cur = cur->next;
- }
- if (chain_len > max_chain_len)
- max_chain_len = chain_len;
- }
- }
- info->slots_used = slots_used;
- info->max_chain_len = max_chain_len;
- }
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