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/*
* Asterisk -- An open source telephony toolkit.
*
* Copyright (C) 2016, Fairview 5 Engineering, LLC
*
* George Joseph <george.joseph@fairview5.com>
*
* See http://www.asterisk.org for more information about
* the Asterisk project. Please do not directly contact
* any of the maintainers of this project for assistance;
* the project provides a web site, mailing lists and IRC
* channels for your use.
*
* This program is free software, distributed under the terms of
* the GNU General Public License Version 2. See the LICENSE file
* at the top of the source tree.
*/
/*! \file
*
* \brief Named Locks
*
* \author George Joseph <george.joseph@fairview5.com>
*/
#include "asterisk.h"
ASTERISK_REGISTER_FILE()
#include "asterisk/_private.h"
#include "asterisk/astobj2.h"
#include "asterisk/named_locks.h"
#include "asterisk/utils.h"
struct ao2_container *named_locks;
#define NAMED_LOCKS_BUCKETS 101
struct named_lock_proxy {
AO2_WEAKPROXY();
char key[0];
};
struct ast_named_lock {
};
static int named_locks_hash(const void *obj, const int flags)
{
const struct named_lock_proxy *lock = obj;
switch (flags & OBJ_SEARCH_MASK) {
case OBJ_SEARCH_KEY:
return ast_str_hash(obj);
case OBJ_SEARCH_OBJECT:
return ast_str_hash(lock->key);
default:
/* Hash can only work on something with a full key. */
ast_assert(0);
return 0;
}
}
static int named_locks_cmp(void *obj_left, void *obj_right, int flags)
{
const struct named_lock_proxy *object_left = obj_left;
const struct named_lock_proxy *object_right = obj_right;
const char *right_key = obj_right;
int cmp;
switch (flags & OBJ_SEARCH_MASK) {
case OBJ_SEARCH_OBJECT:
right_key = object_right->key;
/* Fall through */
case OBJ_SEARCH_KEY:
cmp = strcmp(object_left->key, right_key);
break;
case OBJ_SEARCH_PARTIAL_KEY:
cmp = strncmp(object_left->key, right_key, strlen(right_key));
break;
default:
cmp = 0;
break;
}
return cmp ? 0 : CMP_MATCH;
}
static void named_locks_shutdown(void)
{
ao2_cleanup(named_locks);
}
int ast_named_locks_init(void)
{
named_locks = ao2_container_alloc_hash(AO2_ALLOC_OPT_LOCK_MUTEX, 0,
NAMED_LOCKS_BUCKETS, named_locks_hash, NULL, named_locks_cmp);
if (!named_locks) {
return -1;
}
ast_register_cleanup(named_locks_shutdown);
return 0;
}
static void named_lock_proxy_cb(void *weakproxy, void *data)
{
ao2_unlink(named_locks, weakproxy);
}
struct ast_named_lock *__ast_named_lock_get(const char *filename, int lineno, const char *func,
enum ast_named_lock_type lock_type, const char *keyspace, const char *key)
{
struct named_lock_proxy *proxy = NULL;
struct ast_named_lock *lock = NULL;
int keylen = strlen(keyspace) + strlen(key) + 2;
char *concat_key = ast_alloca(keylen);
sprintf(concat_key, "%s-%s", keyspace, key); /* Safe */
ao2_lock(named_locks);
proxy = ao2_find(named_locks, concat_key, OBJ_SEARCH_KEY | OBJ_NOLOCK);
if (proxy) {
ao2_unlock(named_locks);
lock = __ao2_weakproxy_get_object(proxy, 0, __PRETTY_FUNCTION__, filename, lineno, func);
if (lock) {
/* We have an existing lock and it's not being destroyed. */
ao2_ref(proxy, -1);
ast_assert((ao2_options_get(lock) & AO2_ALLOC_OPT_LOCK_MASK) == lock_type);
return lock;
}
/* the old proxy is being destroyed, clean list before creating/adding new one */
ao2_lock(named_locks);
ao2_unlink_flags(named_locks, proxy, OBJ_NOLOCK);
ao2_ref(proxy, -1);
}
proxy = ao2_t_weakproxy_alloc(sizeof(*proxy) + keylen, NULL, concat_key);
if (!proxy) {
goto failure_cleanup;
}
lock = __ao2_alloc(sizeof(*lock) + keylen, NULL, lock_type, concat_key, filename, lineno, func);
if (!lock) {
goto failure_cleanup;
}
/* We have exclusive access to proxy and lock, no need for locking here. */
if (ao2_weakproxy_set_object(proxy, lock, OBJ_NOLOCK)) {
goto failure_cleanup;
}
if (ao2_weakproxy_subscribe(proxy, named_lock_proxy_cb, NULL, OBJ_NOLOCK)) {
goto failure_cleanup;
}
strcpy(proxy->key, concat_key); /* Safe */
ao2_link_flags(named_locks, proxy, OBJ_NOLOCK);
ao2_unlock(named_locks);
ao2_t_ref(proxy, -1, "Release allocation reference");
return lock;
failure_cleanup:
ao2_unlock(named_locks);
ao2_cleanup(proxy);
ao2_cleanup(lock);
return NULL;
}
int __ast_named_lock_put(const char *filename, int lineno, const char *func,
struct ast_named_lock *lock)
{
if (!lock) {
return -1;
}
__ao2_ref(lock, -1, __PRETTY_FUNCTION__, filename, lineno, func);
return 0;
}
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