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/*
* linux/net/sunrpc/auth.c
*
* Generic RPC client authentication API.
*
* Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
*/
#include <linux/types.h>
#include <linux/sched.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/errno.h>
#include <linux/sunrpc/clnt.h>
#include <linux/spinlock.h>
#ifdef RPC_DEBUG
# define RPCDBG_FACILITY RPCDBG_AUTH
#endif
static DEFINE_SPINLOCK(rpc_authflavor_lock);
static const struct rpc_authops *auth_flavors[RPC_AUTH_MAXFLAVOR] = {
&authnull_ops, /* AUTH_NULL */
&authunix_ops, /* AUTH_UNIX */
NULL, /* others can be loadable modules */
};
static LIST_HEAD(cred_unused);
static unsigned long number_cred_unused;
static u32
pseudoflavor_to_flavor(u32 flavor) {
if (flavor >= RPC_AUTH_MAXFLAVOR)
return RPC_AUTH_GSS;
return flavor;
}
int
rpcauth_register(const struct rpc_authops *ops)
{
rpc_authflavor_t flavor;
int ret = -EPERM;
if ((flavor = ops->au_flavor) >= RPC_AUTH_MAXFLAVOR)
return -EINVAL;
spin_lock(&rpc_authflavor_lock);
if (auth_flavors[flavor] == NULL) {
auth_flavors[flavor] = ops;
ret = 0;
}
spin_unlock(&rpc_authflavor_lock);
return ret;
}
int
rpcauth_unregister(const struct rpc_authops *ops)
{
rpc_authflavor_t flavor;
int ret = -EPERM;
if ((flavor = ops->au_flavor) >= RPC_AUTH_MAXFLAVOR)
return -EINVAL;
spin_lock(&rpc_authflavor_lock);
if (auth_flavors[flavor] == ops) {
auth_flavors[flavor] = NULL;
ret = 0;
}
spin_unlock(&rpc_authflavor_lock);
return ret;
}
struct rpc_auth *
rpcauth_create(rpc_authflavor_t pseudoflavor, struct rpc_clnt *clnt)
{
struct rpc_auth *auth;
const struct rpc_authops *ops;
u32 flavor = pseudoflavor_to_flavor(pseudoflavor);
auth = ERR_PTR(-EINVAL);
if (flavor >= RPC_AUTH_MAXFLAVOR)
goto out;
#ifdef CONFIG_KMOD
if ((ops = auth_flavors[flavor]) == NULL)
request_module("rpc-auth-%u", flavor);
#endif
spin_lock(&rpc_authflavor_lock);
ops = auth_flavors[flavor];
if (ops == NULL || !try_module_get(ops->owner)) {
spin_unlock(&rpc_authflavor_lock);
goto out;
}
spin_unlock(&rpc_authflavor_lock);
auth = ops->create(clnt, pseudoflavor);
module_put(ops->owner);
if (IS_ERR(auth))
return auth;
if (clnt->cl_auth)
rpcauth_release(clnt->cl_auth);
clnt->cl_auth = auth;
out:
return auth;
}
void
rpcauth_release(struct rpc_auth *auth)
{
if (!atomic_dec_and_test(&auth->au_count))
return;
auth->au_ops->destroy(auth);
}
static DEFINE_SPINLOCK(rpc_credcache_lock);
static void
rpcauth_unhash_cred_locked(struct rpc_cred *cred)
{
hlist_del_rcu(&cred->cr_hash);
smp_mb__before_clear_bit();
clear_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags);
}
static void
rpcauth_unhash_cred(struct rpc_cred *cred)
{
spinlock_t *cache_lock;
cache_lock = &cred->cr_auth->au_credcache->lock;
spin_lock(cache_lock);
if (atomic_read(&cred->cr_count) == 0)
rpcauth_unhash_cred_locked(cred);
spin_unlock(cache_lock);
}
/*
* Initialize RPC credential cache
*/
int
rpcauth_init_credcache(struct rpc_auth *auth)
{
struct rpc_cred_cache *new;
int i;
new = kmalloc(sizeof(*new), GFP_KERNEL);
if (!new)
return -ENOMEM;
for (i = 0; i < RPC_CREDCACHE_NR; i++)
INIT_HLIST_HEAD(&new->hashtable[i]);
spin_lock_init(&new->lock);
auth->au_credcache = new;
return 0;
}
/*
* Destroy a list of credentials
*/
static inline
void rpcauth_destroy_credlist(struct list_head *head)
{
struct rpc_cred *cred;
while (!list_empty(head)) {
cred = list_entry(head->next, struct rpc_cred, cr_lru);
list_del_init(&cred->cr_lru);
put_rpccred(cred);
}
}
/*
* Clear the RPC credential cache, and delete those credentials
* that are not referenced.
*/
void
rpcauth_clear_credcache(struct rpc_cred_cache *cache)
{
LIST_HEAD(free);
struct hlist_head *head;
struct rpc_cred *cred;
int i;
spin_lock(&rpc_credcache_lock);
spin_lock(&cache->lock);
for (i = 0; i < RPC_CREDCACHE_NR; i++) {
head = &cache->hashtable[i];
while (!hlist_empty(head)) {
cred = hlist_entry(head->first, struct rpc_cred, cr_hash);
get_rpccred(cred);
if (!list_empty(&cred->cr_lru)) {
list_del(&cred->cr_lru);
number_cred_unused--;
}
list_add_tail(&cred->cr_lru, &free);
rpcauth_unhash_cred_locked(cred);
}
}
spin_unlock(&cache->lock);
spin_unlock(&rpc_credcache_lock);
rpcauth_destroy_credlist(&free);
}
/*
* Destroy the RPC credential cache
*/
void
rpcauth_destroy_credcache(struct rpc_auth *auth)
{
struct rpc_cred_cache *cache = auth->au_credcache;
if (cache) {
auth->au_credcache = NULL;
rpcauth_clear_credcache(cache);
kfree(cache);
}
}
/*
* Remove stale credentials. Avoid sleeping inside the loop.
*/
static int
rpcauth_prune_expired(struct list_head *free, int nr_to_scan)
{
spinlock_t *cache_lock;
struct rpc_cred *cred;
while (!list_empty(&cred_unused)) {
cred = list_entry(cred_unused.next, struct rpc_cred, cr_lru);
list_del_init(&cred->cr_lru);
number_cred_unused--;
if (atomic_read(&cred->cr_count) != 0)
continue;
cache_lock = &cred->cr_auth->au_credcache->lock;
spin_lock(cache_lock);
if (atomic_read(&cred->cr_count) == 0) {
get_rpccred(cred);
list_add_tail(&cred->cr_lru, free);
rpcauth_unhash_cred_locked(cred);
nr_to_scan--;
}
spin_unlock(cache_lock);
if (nr_to_scan == 0)
break;
}
return nr_to_scan;
}
/*
* Run memory cache shrinker.
*/
static int
rpcauth_cache_shrinker(int nr_to_scan, gfp_t gfp_mask)
{
LIST_HEAD(free);
int res;
if (list_empty(&cred_unused))
return 0;
spin_lock(&rpc_credcache_lock);
nr_to_scan = rpcauth_prune_expired(&free, nr_to_scan);
res = (number_cred_unused / 100) * sysctl_vfs_cache_pressure;
spin_unlock(&
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