linux/security/selinux/ss/hashtab.c
Chad Sellers bb24249747 SELinux: ensure keys constant in hashtab_search
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>
2006-11-28 12:04:37 -05:00

165 lines
3 KiB
C

/*
* 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 "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;
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 != NULL && 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 != NULL) {
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 != NULL) {
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;
}