freebsd-dev/contrib/bind9/lib/dns/dbtable.c
2004-09-19 01:30:24 +00:00

292 lines
6.7 KiB
C

/*
* Copyright (C) 2004 Internet Systems Consortium, Inc. ("ISC")
* Copyright (C) 1999-2001 Internet Software Consortium.
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
* REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
* AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
* INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
* LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
* OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
* PERFORMANCE OF THIS SOFTWARE.
*/
/*
* $Id: dbtable.c,v 1.25.12.4 2004/03/09 05:21:08 marka Exp $
*/
/*
* Principal Author: DCL
*/
#include <config.h>
#include <isc/mem.h>
#include <isc/rwlock.h>
#include <isc/util.h>
#include <dns/dbtable.h>
#include <dns/db.h>
#include <dns/rbt.h>
#include <dns/result.h>
struct dns_dbtable {
/* Unlocked. */
unsigned int magic;
isc_mem_t * mctx;
dns_rdataclass_t rdclass;
isc_mutex_t lock;
isc_rwlock_t tree_lock;
/* Locked by lock. */
unsigned int references;
/* Locked by tree_lock. */
dns_rbt_t * rbt;
dns_db_t * default_db;
};
#define DBTABLE_MAGIC ISC_MAGIC('D', 'B', '-', '-')
#define VALID_DBTABLE(dbtable) ISC_MAGIC_VALID(dbtable, DBTABLE_MAGIC)
static void
dbdetach(void *data, void *arg) {
dns_db_t *db = data;
UNUSED(arg);
dns_db_detach(&db);
}
isc_result_t
dns_dbtable_create(isc_mem_t *mctx, dns_rdataclass_t rdclass,
dns_dbtable_t **dbtablep)
{
dns_dbtable_t *dbtable;
isc_result_t result;
REQUIRE(mctx != NULL);
REQUIRE(dbtablep != NULL && *dbtablep == NULL);
dbtable = (dns_dbtable_t *)isc_mem_get(mctx, sizeof(*dbtable));
if (dbtable == NULL)
return (ISC_R_NOMEMORY);
dbtable->rbt = NULL;
result = dns_rbt_create(mctx, dbdetach, NULL, &dbtable->rbt);
if (result != ISC_R_SUCCESS)
goto clean1;
result = isc_mutex_init(&dbtable->lock);
if (result != ISC_R_SUCCESS)
goto clean2;
result = isc_rwlock_init(&dbtable->tree_lock, 0, 0);
if (result != ISC_R_SUCCESS)
goto clean3;
dbtable->default_db = NULL;
dbtable->mctx = mctx;
dbtable->rdclass = rdclass;
dbtable->magic = DBTABLE_MAGIC;
dbtable->references = 1;
*dbtablep = dbtable;
return (ISC_R_SUCCESS);
clean3:
DESTROYLOCK(&dbtable->lock);
clean2:
dns_rbt_destroy(&dbtable->rbt);
clean1:
isc_mem_put(mctx, dbtable, sizeof(*dbtable));
return (result);
}
static inline void
dbtable_free(dns_dbtable_t *dbtable) {
/*
* Caller must ensure that it is safe to call.
*/
RWLOCK(&dbtable->tree_lock, isc_rwlocktype_write);
if (dbtable->default_db != NULL)
dns_db_detach(&dbtable->default_db);
dns_rbt_destroy(&dbtable->rbt);
RWUNLOCK(&dbtable->tree_lock, isc_rwlocktype_write);
isc_rwlock_destroy(&dbtable->tree_lock);
dbtable->magic = 0;
isc_mem_put(dbtable->mctx, dbtable, sizeof(*dbtable));
}
void
dns_dbtable_attach(dns_dbtable_t *source, dns_dbtable_t **targetp) {
REQUIRE(VALID_DBTABLE(source));
REQUIRE(targetp != NULL && *targetp == NULL);
LOCK(&source->lock);
INSIST(source->references > 0);
source->references++;
INSIST(source->references != 0);
UNLOCK(&source->lock);
*targetp = source;
}
void
dns_dbtable_detach(dns_dbtable_t **dbtablep) {
dns_dbtable_t *dbtable;
isc_boolean_t free_dbtable = ISC_FALSE;
REQUIRE(dbtablep != NULL);
dbtable = *dbtablep;
REQUIRE(VALID_DBTABLE(dbtable));
LOCK(&dbtable->lock);
INSIST(dbtable->references > 0);
dbtable->references--;
if (dbtable->references == 0)
free_dbtable = ISC_TRUE;
UNLOCK(&dbtable->lock);
if (free_dbtable)
dbtable_free(dbtable);
*dbtablep = NULL;
}
isc_result_t
dns_dbtable_add(dns_dbtable_t *dbtable, dns_db_t *db) {
isc_result_t result;
dns_db_t *clone;
REQUIRE(VALID_DBTABLE(dbtable));
REQUIRE(dns_db_class(db) == dbtable->rdclass);
clone = NULL;
dns_db_attach(db, &clone);
RWLOCK(&dbtable->tree_lock, isc_rwlocktype_write);
result = dns_rbt_addname(dbtable->rbt, dns_db_origin(clone), clone);
RWUNLOCK(&dbtable->tree_lock, isc_rwlocktype_write);
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);
}
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);
}
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);
}
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_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);
}