C++ RWLOCK函数代码示例

isc_result_t
dns_keytable_find(dns_keytable_t *keytable, dns_name_t *keyname,
		  dns_keynode_t **keynodep)
{
	isc_result_t result;
	dns_rbtnode_t *node = NULL;

	REQUIRE(VALID_KEYTABLE(keytable));
	REQUIRE(keyname != NULL);
	REQUIRE(keynodep != NULL && *keynodep == NULL);

	RWLOCK(&keytable->rwlock, isc_rwlocktype_read);
	result = dns_rbt_findnode(keytable->table, keyname, NULL, &node, NULL,
				  DNS_RBTFIND_NOOPTIONS, NULL, NULL);
	if (result == ISC_R_SUCCESS) {
		if (node->data != NULL) {
			LOCK(&keytable->lock);
			keytable->active_nodes++;
			UNLOCK(&keytable->lock);
			dns_keynode_attach(node->data, keynodep);
		} else
			result = ISC_R_NOTFOUND;
	} else if (result == DNS_R_PARTIALMATCH)
		result = ISC_R_NOTFOUND;
	RWUNLOCK(&keytable->rwlock, isc_rwlocktype_read);

	return (result);
}

void
dns_dbtable_remove(dns_dbtable_t *dbtable, dns_db_t *db) {
	dns_db_t *stored_data = NULL;
	isc_result_t result;
	dns_name_t *name;

	REQUIRE(VALID_DBTABLE(dbtable));

	name = dns_db_origin(db);

	/*
	 * There is a requirement that the association of name with db
	 * be verified.  With the current rbt.c this is expensive to do,
	 * because effectively two find operations are being done, but
	 * deletion is relatively infrequent.
	 * XXXDCL ... this could be cheaper now with dns_rbt_deletenode.
	 */

	RWLOCK(&dbtable->tree_lock, isc_rwlocktype_write);

	result = dns_rbt_findname(dbtable->rbt, name, 0, NULL,
				  (void **) (void *)&stored_data);

	if (result == ISC_R_SUCCESS) {
		INSIST(stored_data == db);

		(void)dns_rbt_deletename(dbtable->rbt, name, ISC_FALSE);
	}

	RWUNLOCK(&dbtable->tree_lock, isc_rwlocktype_write);
}

isc_result_t
dns_keytable_issecuredomain(dns_keytable_t *keytable, dns_name_t *name,
			    dns_name_t *foundname, isc_boolean_t *wantdnssecp)
{
	isc_result_t result;
	dns_rbtnode_t *node = NULL;

	/*
	 * Is 'name' at or beneath a trusted key?
	 */

	REQUIRE(VALID_KEYTABLE(keytable));
	REQUIRE(dns_name_isabsolute(name));
	REQUIRE(wantdnssecp != NULL);

	RWLOCK(&keytable->rwlock, isc_rwlocktype_read);

	result = dns_rbt_findnode(keytable->table, name, foundname, &node,
				  NULL, DNS_RBTFIND_NOOPTIONS, NULL, NULL);
	if (result == ISC_R_SUCCESS || result == DNS_R_PARTIALMATCH) {
		INSIST(node->data != NULL);
		*wantdnssecp = ISC_TRUE;
		result = ISC_R_SUCCESS;
	} else if (result == ISC_R_NOTFOUND) {
		*wantdnssecp = ISC_FALSE;
		result = ISC_R_SUCCESS;
	}

	RWUNLOCK(&keytable->rwlock, isc_rwlocktype_read);

	return (result);
}

isc_result_t
dns_keytable_finddeepestmatch(dns_keytable_t *keytable, dns_name_t *name,
			      dns_name_t *foundname)
{
	isc_result_t result;
	void *data;

	/*
	 * Search for the deepest match in 'keytable'.
	 */

	REQUIRE(VALID_KEYTABLE(keytable));
	REQUIRE(dns_name_isabsolute(name));
	REQUIRE(foundname != NULL);

	RWLOCK(&keytable->rwlock, isc_rwlocktype_read);

	data = NULL;
	result = dns_rbt_findname(keytable->table, name, 0, foundname, &data);

	if (result == ISC_R_SUCCESS || result == DNS_R_PARTIALMATCH)
		result = ISC_R_SUCCESS;

	RWUNLOCK(&keytable->rwlock, isc_rwlocktype_read);

	return (result);
}

void
dns_keytable_detach(dns_keytable_t **keytablep) {
	isc_boolean_t destroy = ISC_FALSE;
	dns_keytable_t *keytable;

	/*
	 * Detach *keytablep from its keytable.
	 */

	REQUIRE(keytablep != NULL && VALID_KEYTABLE(*keytablep));

	keytable = *keytablep;

	RWLOCK(&keytable->rwlock, isc_rwlocktype_write);

	INSIST(keytable->references > 0);
	keytable->references--;
	LOCK(&keytable->lock);
	if (keytable->references == 0 && keytable->active_nodes == 0)
		destroy = ISC_TRUE;
	UNLOCK(&keytable->lock);

	RWUNLOCK(&keytable->rwlock, isc_rwlocktype_write);

	if (destroy) {
		dns_rbt_destroy(&keytable->table);
		isc_rwlock_destroy(&keytable->rwlock);
		DESTROYLOCK(&keytable->lock);
		keytable->magic = 0;
		isc_mem_putanddetach(&keytable->mctx,
				     keytable, sizeof(*keytable));
	}

	*keytablep = NULL;
}

isc_result_t
dns_tsigkeyring_dumpanddetach(dns_tsig_keyring_t **ringp, FILE *fp) {
	isc_result_t result;
	dns_rbtnodechain_t chain;
	dns_name_t foundname;
	dns_fixedname_t fixedorigin;
	dns_name_t *origin;
	isc_stdtime_t now;
	dns_rbtnode_t *node;
	dns_tsigkey_t *tkey;
	dns_tsig_keyring_t *ring;
	unsigned int references;

	REQUIRE(ringp != NULL && *ringp != NULL);

	ring = *ringp;
	*ringp = NULL;

	RWLOCK(&ring->lock, isc_rwlocktype_write);
	INSIST(ring->references > 0);
	ring->references--;
	references = ring->references;
	RWUNLOCK(&ring->lock, isc_rwlocktype_write);

	if (references != 0)
		return (DNS_R_CONTINUE);

	isc_stdtime_get(&now);
	dns_name_init(&foundname, NULL);
	dns_fixedname_init(&fixedorigin);
	origin = dns_fixedname_name(&fixedorigin);
	dns_rbtnodechain_init(&chain, ring->mctx);
	result = dns_rbtnodechain_first(&chain, ring->keys, &foundname,
					origin);
	if (result != ISC_R_SUCCESS && result != DNS_R_NEWORIGIN) {
		dns_rbtnodechain_invalidate(&chain);
		goto destroy;
	}

	for (;;) {
		node = NULL;
		dns_rbtnodechain_current(&chain, &foundname, origin, &node);
		tkey = node->data;
		if (tkey != NULL && tkey->generated && tkey->expire >= now)
			dump_key(tkey, fp);
		result = dns_rbtnodechain_next(&chain, &foundname,
					       origin);
		if (result != ISC_R_SUCCESS && result != DNS_R_NEWORIGIN) {
			dns_rbtnodechain_invalidate(&chain);
			if (result == ISC_R_NOMORE)
				result = ISC_R_SUCCESS;
			goto destroy;
		}
	}

 destroy:
	destroyring(ring);
	return (result);
}

void
dns_tsigkey_setdeleted(dns_tsigkey_t *key) {
	REQUIRE(VALID_TSIG_KEY(key));
	REQUIRE(key->ring != NULL);

	RWLOCK(&key->ring->lock, isc_rwlocktype_write);
	(void)dns_rbt_deletename(key->ring->keys, &key->name, ISC_FALSE);
	RWUNLOCK(&key->ring->lock, isc_rwlocktype_write);
}

void
dns_tsigkey_setdeleted(dns_tsigkey_t *key) {
	REQUIRE(VALID_TSIG_KEY(key));
	REQUIRE(key->ring != NULL);

	RWLOCK(&key->ring->lock, isc_rwlocktype_write);
	remove_fromring(key);
	RWUNLOCK(&key->ring->lock, isc_rwlocktype_write);
}

isc_result_t
dns_keytable_findkeynode(dns_keytable_t *keytable, dns_name_t *name,
			 dns_secalg_t algorithm, dns_keytag_t tag,
			 dns_keynode_t **keynodep)
{
	isc_result_t result;
	dns_keynode_t *knode;
	void *data;

	/*
	 * Search for a key named 'name', matching 'algorithm' and 'tag' in
	 * 'keytable'.
	 */

	REQUIRE(VALID_KEYTABLE(keytable));
	REQUIRE(dns_name_isabsolute(name));
	REQUIRE(keynodep != NULL && *keynodep == NULL);

	RWLOCK(&keytable->rwlock, isc_rwlocktype_read);

	/*
	 * Note we don't want the DNS_R_PARTIALMATCH from dns_rbt_findname()
	 * as that indicates that 'name' was not found.
	 *
	 * DNS_R_PARTIALMATCH indicates that the name was found but we
	 * didn't get a match on algorithm and key id arguments.
	 */
	knode = NULL;
	data = NULL;
	result = dns_rbt_findname(keytable->table, name, 0, NULL, &data);

	if (result == ISC_R_SUCCESS) {
		INSIST(data != NULL);
		for (knode = data; knode != NULL; knode = knode->next) {
			if (knode->key == NULL) {
				knode = NULL;
				break;
			}
			if (algorithm == dst_key_alg(knode->key)
			    && tag == dst_key_id(knode->key))
				break;
		}
		if (knode != NULL) {
			LOCK(&keytable->lock);
			keytable->active_nodes++;
			UNLOCK(&keytable->lock);
			dns_keynode_attach(knode, keynodep);
		} else
			result = DNS_R_PARTIALMATCH;
	} else if (result == DNS_R_PARTIALMATCH)
		result = ISC_R_NOTFOUND;

	RWUNLOCK(&keytable->rwlock, isc_rwlocktype_read);

	return (result);
}

void
dns_dbtable_removedefault(dns_dbtable_t *dbtable) {
	REQUIRE(VALID_DBTABLE(dbtable));

	RWLOCK(&dbtable->tree_lock, isc_rwlocktype_write);

	dns_db_detach(&dbtable->default_db);

	RWUNLOCK(&dbtable->tree_lock, isc_rwlocktype_write);
}

isc_result_t
dns_zt_freezezones(dns_zt_t *zt, isc_boolean_t freeze) {
	isc_result_t result, tresult;

	REQUIRE(VALID_ZT(zt));

	RWLOCK(&zt->rwlock, isc_rwlocktype_read);
	result = dns_zt_apply2(zt, ISC_FALSE, &tresult, freezezones, &freeze);
	RWUNLOCK(&zt->rwlock, isc_rwlocktype_read);
	return ((result == ISC_R_SUCCESS) ? tresult : result);
}

isc_result_t
dns_zt_loadnew(dns_zt_t *zt, isc_boolean_t stop) {
	isc_result_t result;

	REQUIRE(VALID_ZT(zt));

	RWLOCK(&zt->rwlock, isc_rwlocktype_read);
	result = dns_zt_apply(zt, stop, loadnew, NULL);
	RWUNLOCK(&zt->rwlock, isc_rwlocktype_read);
	return (result);
}

void
dns_dbtable_getdefault(dns_dbtable_t *dbtable, dns_db_t **dbp) {
	REQUIRE(VALID_DBTABLE(dbtable));
	REQUIRE(dbp != NULL && *dbp == NULL);

	RWLOCK(&dbtable->tree_lock, isc_rwlocktype_read);

	dns_db_attach(dbtable->default_db, dbp);

	RWUNLOCK(&dbtable->tree_lock, isc_rwlocktype_read);
}

isc_result_t
dns_tsigkey_find(dns_tsigkey_t **tsigkey, dns_name_t *name,
		 dns_name_t *algorithm, dns_tsig_keyring_t *ring)
{
	dns_tsigkey_t *key;
	isc_stdtime_t now;
	isc_result_t result;

	REQUIRE(tsigkey != NULL);
	REQUIRE(*tsigkey == NULL);
	REQUIRE(name != NULL);
	REQUIRE(ring != NULL);

	isc_stdtime_get(&now);
	RWLOCK(&ring->lock, isc_rwlocktype_read);
	key = NULL;
	result = dns_rbt_findname(ring->keys, name, 0, NULL, (void *)&key);
	if (result == DNS_R_PARTIALMATCH || result == ISC_R_NOTFOUND) {
		RWUNLOCK(&ring->lock, isc_rwlocktype_read);
		return (ISC_R_NOTFOUND);
	}
	if (algorithm != NULL && !dns_name_equal(key->algorithm, algorithm)) {
		RWUNLOCK(&ring->lock, isc_rwlocktype_read);
		return (ISC_R_NOTFOUND);
	}
	if (key->inception != key->expire && key->expire < now) {
		/*
		 * The key has expired.
		 */
		RWUNLOCK(&ring->lock, isc_rwlocktype_read);
		RWLOCK(&ring->lock, isc_rwlocktype_write);
		(void) dns_rbt_deletename(ring->keys, name, ISC_FALSE);
		RWUNLOCK(&ring->lock, isc_rwlocktype_write);
		return (ISC_R_NOTFOUND);
	}

	isc_refcount_increment(&key->refs, NULL);
	RWUNLOCK(&ring->lock, isc_rwlocktype_read);
	*tsigkey = key;
	return (ISC_R_SUCCESS);
}

void
dns_dbtable_adddefault(dns_dbtable_t *dbtable, dns_db_t *db) {
	REQUIRE(VALID_DBTABLE(dbtable));
	REQUIRE(dbtable->default_db == NULL);
	REQUIRE(dns_name_compare(dns_db_origin(db), dns_rootname) == 0);

	RWLOCK(&dbtable->tree_lock, isc_rwlocktype_write);

	dbtable->default_db = NULL;
	dns_db_attach(db, &dbtable->default_db);

	RWUNLOCK(&dbtable->tree_lock, isc_rwlocktype_write);
}