C++ RWUNLOCK函数代码示例

isc_result_t
dns_db_create(isc_mem_t *mctx, const char *db_type, dns_name_t *origin,
	      dns_dbtype_t type, dns_rdataclass_t rdclass,
	      unsigned int argc, char *argv[], dns_db_t **dbp)
{
	dns_dbimplementation_t *impinfo;

	RUNTIME_CHECK(isc_once_do(&once, initialize) == ISC_R_SUCCESS);

	/*
	 * Create a new database using implementation 'db_type'.
	 */

	REQUIRE(dbp != NULL && *dbp == NULL);
	REQUIRE(dns_name_isabsolute(origin));

	RWLOCK(&implock, isc_rwlocktype_read);
	impinfo = impfind(db_type);
	if (impinfo != NULL) {
		isc_result_t result;
		result = ((impinfo->create)(mctx, origin, type,
					    rdclass, argc, argv,
					    impinfo->driverarg, dbp));
		RWUNLOCK(&implock, isc_rwlocktype_read);
		return (result);
	}

	RWUNLOCK(&implock, isc_rwlocktype_read);

	isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
		      DNS_LOGMODULE_DB, ISC_LOG_ERROR,
		      "unsupported database type '%s'", db_type);

	return (ISC_R_NOTFOUND);
}

/*
 * A supplemental routine just to add a key to ring.  Note that reference
 * counter should be counted separately because we may be adding the key
 * as part of creation of the key, in which case the reference counter was
 * already initialized.  Also note we don't need RWLOCK for the reference
 * counter: it's protected by a separate lock.
 */
static isc_result_t
keyring_add(dns_tsig_keyring_t *ring, dns_name_t *name,
	    dns_tsigkey_t *tkey)
{
	isc_result_t result;

	RWLOCK(&ring->lock, isc_rwlocktype_write);
	ring->writecount++;

	/*
	 * Do on the fly cleaning.  Find some nodes we might not
	 * want around any more.
	 */
	if (ring->writecount > 10) {
		cleanup_ring(ring);
		ring->writecount = 0;
	}

	result = dns_rbt_addname(ring->keys, name, tkey);
	if (result == ISC_R_SUCCESS && tkey->generated) {
		/*
		 * Add the new key to the LRU list and remove the least
		 * recently used key if there are too many keys on the list.
		 */
		ISC_LIST_APPEND(ring->lru, tkey, link);
		if (ring->generated++ > ring->maxgenerated)
			remove_fromring(ISC_LIST_HEAD(ring->lru));
	}
	RWUNLOCK(&ring->lock, isc_rwlocktype_write);

	return (result);
}

isc_result_t
dns_zt_asyncload(dns_zt_t *zt, dns_zt_allloaded_t alldone, void *arg) {
	isc_result_t result;
	static dns_zt_zoneloaded_t dl = doneloading;
	int pending;

	REQUIRE(VALID_ZT(zt));

	RWLOCK(&zt->rwlock, isc_rwlocktype_write);

	INSIST(zt->loads_pending == 0);
	result = dns_zt_apply2(zt, ISC_FALSE, NULL, asyncload, &dl);

	pending = zt->loads_pending;
	if (pending != 0) {
		zt->loaddone = alldone;
		zt->loaddone_arg = arg;
	}

	RWUNLOCK(&zt->rwlock, isc_rwlocktype_write);

	if (pending == 0)
		alldone(arg);

	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);
}

isc_result_t
dns_keytable_issecuredomain(dns_keytable_t *keytable, dns_name_t *name,
			    isc_boolean_t *wantdnssecp)
{
	isc_result_t result;
	void *data;

	/*
	 * 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);

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

	if (result == ISC_R_SUCCESS || result == DNS_R_PARTIALMATCH) {
		INSIST(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_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);
}

static void
zt_flushanddetach(dns_zt_t **ztp, isc_boolean_t need_flush) {
	isc_boolean_t destroy = ISC_FALSE;
	dns_zt_t *zt;

	REQUIRE(ztp != NULL && VALID_ZT(*ztp));

	zt = *ztp;

	RWLOCK(&zt->rwlock, isc_rwlocktype_write);

	INSIST(zt->references > 0);
	zt->references--;
	if (zt->references == 0)
		destroy = ISC_TRUE;
	if (need_flush)
		zt->flush = ISC_TRUE;

	RWUNLOCK(&zt->rwlock, isc_rwlocktype_write);

	if (destroy)
		zt_destroy(zt);

	*ztp = NULL;
}

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;
}

/*
 * Decrement the loads_pending counter; when counter reaches
 * zero, call the loaddone callback that was initially set by
 * dns_zt_asyncload().
 */
static isc_result_t
doneloading(dns_zt_t *zt, dns_zone_t *zone, isc_task_t *task) {
	isc_boolean_t destroy = ISC_FALSE;
	dns_zt_allloaded_t alldone = NULL;
	void *arg = NULL;

	UNUSED(zone);
	UNUSED(task);

	REQUIRE(VALID_ZT(zt));

	RWLOCK(&zt->rwlock, isc_rwlocktype_write);
	INSIST(zt->loads_pending != 0);
	INSIST(zt->references != 0);
	zt->references--;
	if (zt->references == 0)
		destroy = ISC_TRUE;
	zt->loads_pending--;
	if (zt->loads_pending == 0) {
		alldone = zt->loaddone;
		arg = zt->loaddone_arg;
		zt->loaddone = NULL;
		zt->loaddone_arg = NULL;
	}
	RWUNLOCK(&zt->rwlock, isc_rwlocktype_write);

	if (alldone != NULL)
		alldone(arg);

	if (destroy)
		zt_destroy(zt);

	return (ISC_R_SUCCESS);
}

static void
zt_flushanddetach(dns_zt_t **ztp, isc_boolean_t need_flush) {
	isc_boolean_t destroy = ISC_FALSE;
	dns_zt_t *zt;

	REQUIRE(ztp != NULL && VALID_ZT(*ztp));

	zt = *ztp;

	RWLOCK(&zt->rwlock, isc_rwlocktype_write);

	INSIST(zt->references > 0);
	zt->references--;
	if (zt->references == 0)
		destroy = ISC_TRUE;

	RWUNLOCK(&zt->rwlock, isc_rwlocktype_write);

	if (destroy) {
		if (need_flush)
			(void)dns_zt_apply(zt, ISC_FALSE, flush, NULL);
		dns_rbt_destroy(&zt->table);
		isc_rwlock_destroy(&zt->rwlock);
		zt->magic = 0;
		isc_mem_put(zt->mctx, zt, sizeof(*zt));
	}

	*ztp = NULL;
}

isc_result_t
dns_dbtable_find(dns_dbtable_t *dbtable, dns_name_t *name,
		 unsigned int options, dns_db_t **dbp)
{
	dns_db_t *stored_data = NULL;
	isc_result_t result;
	unsigned int rbtoptions = 0;

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

	if ((options & DNS_DBTABLEFIND_NOEXACT) != 0)
		rbtoptions |= DNS_RBTFIND_NOEXACT;

	RWLOCK(&dbtable->tree_lock, isc_rwlocktype_read);

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

	if (result == ISC_R_SUCCESS || result == DNS_R_PARTIALMATCH)
		dns_db_attach(stored_data, dbp);
	else if (dbtable->default_db != NULL) {
		dns_db_attach(dbtable->default_db, dbp);
		result = DNS_R_PARTIALMATCH;
	} else
		result = ISC_R_NOTFOUND;

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

static int find_i(T *thiz, mkey_t *key, mval_t *v, mkv_t *tkv)
{
    int r, i;
    hdr_block_t *hdr;
    off_t off;
    fkv_t fkv;

    fkv.kv = tkv;

    RWLOCK_READ(LOCK);

    r = krange_cmp(thiz, key);
    if (r != 0) {
        r = RC_NOT_FOUND;
        goto _out;
    }

    hdr = thiz->hdr;
    off = (hdr->node_cnt - 1) * BTR_INDEX_BLK_SIZE; /* root off */

    for (i = 0; i < hdr->tree_heigh; i++) {
        off = find_in_index(thiz, off, key, NULL);
        if (off <= 0) {
            r = RC_NOT_FOUND;
            goto _out;
        }

        off = off - (off_t)(hdr->leaf_off);
    }

    r = find_in_leaf(thiz, off, key, &fkv, NULL);
    if (r != 0) {
        r = RC_NOT_FOUND;
        goto _out;
    }

    if (v != NULL) {
        v->len = tkv->v.len;
        v->data = MY_Malloc(v->len);

        r = read_val(thiz->rfd, fkv.blkoff, fkv.voff, v);
        if (r != 0) {
            r = RC_ERR;
            MY_Free(v->data);
            goto _out;
        }

        tkv->v.data = v->data;
        check_fval(thiz->rfd, tkv);
    }

    r = RC_FOUND;
    DEBUG("hit %.*s in %s", (int)key->len, key->data, thiz->file);

_out:
    RWUNLOCK(LOCK);

    return r;
}

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);
}