1
0
Fork 0
mirror of synced 2025-03-06 20:59:54 +01:00
linux/security/selinux/ss/hashtab.c
Paul Moore dfd9bb40a4 selinux: fix style issues in security/selinux/ss/hashtab.c
As part of on ongoing effort to perform more automated testing and
provide more tools for individual developers to validate their
patches before submitting, we are trying to make our code
"clang-format clean".  My hope is that once we have fixed all of our
style "quirks", developers will be able to run clang-format on their
patches to help avoid silly formatting problems and ensure their
changes fit in well with the rest of the SELinux kernel code.

Signed-off-by: Paul Moore <paul@paul-moore.com>
2024-02-23 17:26:05 -05:00

198 lines
4.3 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* Implementation of the hash table type.
*
* Author : Stephen Smalley, <stephen.smalley.work@gmail.com>
*/
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/errno.h>
#include "hashtab.h"
#include "security.h"
static struct kmem_cache *hashtab_node_cachep __ro_after_init;
/*
* Here we simply round the number of elements up to the nearest power of two.
* I tried also other options like rounding down or rounding to the closest
* power of two (up or down based on which is closer), but I was unable to
* find any significant difference in lookup/insert performance that would
* justify switching to a different (less intuitive) formula. It could be that
* a different formula is actually more optimal, but any future changes here
* should be supported with performance/memory usage data.
*
* The total memory used by the htable arrays (only) with Fedora policy loaded
* is approximately 163 KB at the time of writing.
*/
static u32 hashtab_compute_size(u32 nel)
{
return nel == 0 ? 0 : roundup_pow_of_two(nel);
}
int hashtab_init(struct hashtab *h, u32 nel_hint)
{
u32 size = hashtab_compute_size(nel_hint);
/* should already be zeroed, but better be safe */
h->nel = 0;
h->size = 0;
h->htable = NULL;
if (size) {
h->htable = kcalloc(size, sizeof(*h->htable), GFP_KERNEL);
if (!h->htable)
return -ENOMEM;
h->size = size;
}
return 0;
}
int __hashtab_insert(struct hashtab *h, struct hashtab_node **dst, void *key,
void *datum)
{
struct hashtab_node *newnode;
newnode = kmem_cache_zalloc(hashtab_node_cachep, GFP_KERNEL);
if (!newnode)
return -ENOMEM;
newnode->key = key;
newnode->datum = datum;
newnode->next = *dst;
*dst = newnode;
h->nel++;
return 0;
}
void hashtab_destroy(struct hashtab *h)
{
u32 i;
struct hashtab_node *cur, *temp;
for (i = 0; i < h->size; i++) {
cur = h->htable[i];
while (cur) {
temp = cur;
cur = cur->next;
kmem_cache_free(hashtab_node_cachep, temp);
}
h->htable[i] = NULL;
}
kfree(h->htable);
h->htable = NULL;
}
int hashtab_map(struct hashtab *h, int (*apply)(void *k, void *d, void *args),
void *args)
{
u32 i;
int ret;
struct hashtab_node *cur;
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;
}
#ifdef CONFIG_SECURITY_SELINUX_DEBUG
void hashtab_stat(struct hashtab *h, struct hashtab_info *info)
{
u32 i, chain_len, slots_used, max_chain_len;
u64 chain2_len_sum;
struct hashtab_node *cur;
slots_used = 0;
max_chain_len = 0;
chain2_len_sum = 0;
for (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;
chain2_len_sum += (u64)chain_len * chain_len;
}
}
info->slots_used = slots_used;
info->max_chain_len = max_chain_len;
info->chain2_len_sum = chain2_len_sum;
}
#endif /* CONFIG_SECURITY_SELINUX_DEBUG */
int hashtab_duplicate(struct hashtab *new, struct hashtab *orig,
int (*copy)(struct hashtab_node *new,
struct hashtab_node *orig, void *args),
int (*destroy)(void *k, void *d, void *args), void *args)
{
struct hashtab_node *cur, *tmp, *tail;
u32 i;
int rc;
memset(new, 0, sizeof(*new));
new->htable = kcalloc(orig->size, sizeof(*new->htable), GFP_KERNEL);
if (!new->htable)
return -ENOMEM;
new->size = orig->size;
for (i = 0; i < orig->size; i++) {
tail = NULL;
for (cur = orig->htable[i]; cur; cur = cur->next) {
tmp = kmem_cache_zalloc(hashtab_node_cachep,
GFP_KERNEL);
if (!tmp)
goto error;
rc = copy(tmp, cur, args);
if (rc) {
kmem_cache_free(hashtab_node_cachep, tmp);
goto error;
}
tmp->next = NULL;
if (!tail)
new->htable[i] = tmp;
else
tail->next = tmp;
tail = tmp;
new->nel++;
}
}
return 0;
error:
for (i = 0; i < new->size; i++) {
for (cur = new->htable[i]; cur; cur = tmp) {
tmp = cur->next;
destroy(cur->key, cur->datum, args);
kmem_cache_free(hashtab_node_cachep, cur);
}
}
kfree(new->htable);
memset(new, 0, sizeof(*new));
return -ENOMEM;
}
void __init hashtab_cache_init(void)
{
hashtab_node_cachep = kmem_cache_create("hashtab_node",
sizeof(struct hashtab_node), 0,
SLAB_PANIC, NULL);
}