/*
 * Copyright (C) 2002 Stichting NLnet, Netherlands, stichting@nlnet.nl.
 *
 * 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 STICHTING NLNET
 * DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL
 * STICHTING NLNET 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.
 *
 * The development of Dynamically Loadable Zones (DLZ) for Bind 9 was
 * conceived and contributed by Rob Butler.
 *
 * 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 ROB BUTLER
 * DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL
 * ROB BUTLER 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.
 */

/*
 * 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 INTERNET SOFTWARE CONSORTIUM
 * DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL
 * INTERNET SOFTWARE CONSORTIUM 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.
 */

#ifdef DLZ_BDB

#include <config.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>

#include <dns/log.h>
#include <dns/sdlz.h>
#include <dns/result.h>

#include <isc/mem.h>
#include <isc/print.h>
#include <isc/result.h>
#include <isc/util.h>

#include <named/globals.h>

#include <dlz/dlz_bdbhpt_driver.h>

#include <db.h>

static dns_sdlzimplementation_t *dlz_bdbhpt = NULL;

/* should the bdb driver use threads. */
#ifdef ISC_PLATFORM_USETHREADS
#define bdbhpt_threads DB_THREAD
#else
#define bdbhpt_threads 0
#endif

/* bdbhpt database names */
#define dlz_data "dns_data"
#define dlz_zone "dns_zone"
#define dlz_xfr "dns_xfr"
#define dlz_client "dns_client"

	/* This structure contains all the Berkeley DB handles
	 * for this instance of the bdbhpt driver.
	 */

typedef struct bdbhpt_instance {
	DB_ENV	*dbenv;		/*%< bdbhpt environment */
	DB	*data;		/*%< dns_data database handle */
	DB	*zone;		/*%< zone database handle */
	DB	*xfr;		/*%< zone xfr database handle */
	DB	*client;	/*%< client database handle */
	isc_mem_t *mctx;	/*%< memory context */

} bdbhpt_instance_t;

typedef struct bdbhpt_parsed_data {
	char *host;
	char *type;
	int ttl;
	char *data;
} bdbhpt_parsed_data_t;


/* forward reference */

static isc_result_t
bdbhpt_findzone(void *driverarg, void *dbdata, const char *name,
		dns_clientinfomethods_t *methods, dns_clientinfo_t *clientinfo);

/*%
 * Reverses a string in place.
 */

static char *bdbhpt_strrev(char *str)
{
	char *p1, *p2;

	if (! str || ! *str)
		return str;
	for (p1 = str, p2 = str + strlen(str) - 1; p2 > p1; ++p1, --p2)
	{
		*p1 ^= *p2;
		*p2 ^= *p1;
		*p1 ^= *p2;
	}
	return str;
}

/*%
 * Parses the DBT from the Berkeley DB into a parsed_data record
 * The parsed_data record should be allocated before and passed into the
 * bdbhpt_parse_data function.  The char (type & data) fields should not
 * be "free"d as that memory is part of the DBT data field.  It will be
 * "free"d when the DBT is freed.
 */

static isc_result_t
bdbhpt_parse_data(char *in, bdbhpt_parsed_data_t *pd) {

	char *endp, *ttlStr;
	char *tmp = in;
	char *lastchar = (char *) &tmp[strlen(tmp)];

	/*%
	 * String should be formated as:
	 *   replication_id
	 *   (a space)
	 *   host_name
	 *   (a space)
	 *   ttl
	 *   (a space)
	 *   type
	 *   (a space)
	 *   remaining data
	 *
	 * examples:
	 *
	 * 9191 host 10 A 127.0.0.1
	 * server1_212 host 10 A 127.0.0.2
	 * {xxxx-xxxx-xxxx-xxxx-xxxx} host 10 MX 20 mail.example.com
	 */

	/*
	 * we don't need the replication id, so don't
	 * bother saving a pointer to it.
	 */

	/* find space after replication id */
	tmp = strchr(tmp, ' ');
	/* verify we found a space */
	if (tmp == NULL)
		return ISC_R_FAILURE;
	/* make sure it is safe to increment pointer */
	if (++tmp > lastchar)
		return ISC_R_FAILURE;

	/* save pointer to host */
	pd->host = tmp;

	/* find space after host and change it to a '\0' */
	tmp = strchr(tmp, ' ');
	/* verify we found a space */
	if (tmp == NULL)
		return ISC_R_FAILURE;
	/* change the space to a null (string terminator) */
	tmp[0] = '\0';
	/* make sure it is safe to increment pointer */
	if (++tmp > lastchar)
		return ISC_R_FAILURE;

	/* save pointer to ttl string */
	ttlStr = tmp;

	/* find space after ttl and change it to a '\0' */
	tmp = strchr(tmp, ' ');
	/* verify we found a space */
	if (tmp == NULL)
		return ISC_R_FAILURE;
	/* change the space to a null (string terminator) */
	tmp[0] = '\0';
	/* make sure it is safe to increment pointer */
	if (++tmp > lastchar)
		return ISC_R_FAILURE;

	/* save pointer to dns type */
	pd->type = tmp;

	/* find space after type and change it to a '\0' */
	tmp = strchr(tmp, ' ');
	/* verify we found a space */
	if (tmp == NULL)
		return ISC_R_FAILURE;
	/* change the space to a null (string terminator) */
	tmp[0] = '\0';
	/* make sure it is safe to increment pointer */
	if (++tmp > lastchar)
		return ISC_R_FAILURE;

	/* save pointer to remainder of DNS data */
	pd->data = tmp;

	/* convert ttl string to integer */
	pd->ttl = strtol(ttlStr, &endp, 10);
	if (*endp != '\0' || pd->ttl < 0) {
		isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
			      DNS_LOGMODULE_DLZ, ISC_LOG_ERROR,
			      "bdbhpt driver ttl must be a postive number");
		return ISC_R_FAILURE;
	}

	/* if we get this far everything should have worked. */
	return ISC_R_SUCCESS;
}

/*
 * DLZ methods
 */

static isc_result_t
bdbhpt_allowzonexfr(void *driverarg, void *dbdata, const char *name,
		    const char *client)
{
	isc_result_t result;
	bdbhpt_instance_t *db = (bdbhpt_instance_t *) dbdata;
	DBT key, data;

	/* check to see if we are authoritative for the zone first. */
	result = bdbhpt_findzone(driverarg, dbdata, name, NULL, NULL);
	if (result != ISC_R_SUCCESS)
		return (ISC_R_NOTFOUND);

	memset(&key, 0, sizeof(DBT));
	key.flags = DB_DBT_MALLOC;
	key.data = strdup(name);
	if (key.data == NULL) {
		result = ISC_R_NOMEMORY;
		goto xfr_cleanup;
	}
	key.size = strlen(key.data);

	memset(&data, 0, sizeof(DBT));
	data.flags = DB_DBT_MALLOC;
	data.data = strdup(client);
	if (data.data == NULL) {
		result = ISC_R_NOMEMORY;
		goto xfr_cleanup;
	}
	data.size = strlen(data.data);

	switch(db->client->get(db->client, NULL, &key, &data, DB_GET_BOTH)) {
	case DB_NOTFOUND:
		result = ISC_R_NOTFOUND;
		break;
	case 0:
		result = ISC_R_SUCCESS;
		break;
	default:
		result = ISC_R_FAILURE;
	}

 xfr_cleanup:

	/* free any memory duplicate string in the key field */
	if (key.data != NULL)
		free(key.data);

	/* free any memory allocated to the data field. */
	if (data.data != NULL)
		free(data.data);

	return result;

}

/*%
 * BDB does not allow a secondary index on a database that allows
 * duplicates.  We have a few options:
 *
 * 1) kill speed by having lookup method use a secondary db which
 * is associated to the primary DB with the DNS data.  Then have
 * another secondary db for zone transfer which also points to
 * the dns_data primary.  NO - The  point of this driver is
 * lookup performance.
 *
 * 2) Blow up database size by storing DNS data twice.  Once for
 * the lookup (dns_data) database, and a second time for the zone
 * transfer (dns_xfr) database. NO - That would probably require
 * a larger cache to provide good performance.  Also, that would
 * make the DB larger on disk potentially slowing it as well.
 *
 * 3) Loop through the dns_xfr database with a cursor to get
 * all the different hosts in a zone.  Then use the zone & host
 * together to lookup the data in the dns_data database. YES -
 * This may slow down zone xfr's a little, but that's ok they
 * don't happen as often and don't need to be as fast. We can
 * also use this table when deleting a zone (The BDB driver
 * is read only - the delete would be used during replication
 * updates by a separate process).
 */

static isc_result_t
bdbhpt_allnodes(const char *zone, void *driverarg, void *dbdata,
		dns_sdlzallnodes_t *allnodes)
{

	isc_result_t result = ISC_R_NOTFOUND;
	bdbhpt_instance_t *db = (bdbhpt_instance_t *) dbdata;
	DBC *xfr_cursor = NULL;
	DBC *dns_cursor = NULL;
	DBT xfr_key, xfr_data, dns_key, dns_data;
	int xfr_flags;
	int dns_flags;
	int bdbhptres;
	bdbhpt_parsed_data_t pd;
	char *tmp = NULL, *tmp_zone, *tmp_zone_host = NULL;

	UNUSED(driverarg);

	memset(&xfr_key, 0, sizeof(DBT));
	memset(&xfr_data, 0, sizeof(DBT));
	memset(&dns_key, 0, sizeof(DBT));
	memset(&dns_data, 0, sizeof(DBT));

	xfr_key.data = tmp_zone = strdup(zone);
	if (xfr_key.data == NULL)
		return (ISC_R_NOMEMORY);

	xfr_key.size = strlen(xfr_key.data);

	/* get a cursor to loop through dns_xfr table */
	if (db->xfr->cursor(db->xfr, NULL, &xfr_cursor, 0) != 0) {
		result = ISC_R_FAILURE;
		goto allnodes_cleanup;
	}

	/* get a cursor to loop through dns_data table */
	if (db->data->cursor(db->data, NULL, &dns_cursor, 0) != 0) {
		result = ISC_R_FAILURE;
		goto allnodes_cleanup;
	}

	xfr_flags = DB_SET;

	/* loop through xfr table for specified zone. */
	while ((bdbhptres = xfr_cursor->c_get(xfr_cursor, &xfr_key, &xfr_data,
					      xfr_flags)) == 0) {

		xfr_flags = DB_NEXT_DUP;

		/* +1 to allow for space between zone and host names */
		dns_key.size = xfr_data.size + xfr_key.size + 1;

		/* +1 to allow for null term at end of string. */
		dns_key.data = tmp_zone_host = malloc(dns_key.size + 1);
		if (dns_key.data == NULL)
			goto allnodes_cleanup;

		/*
		 * construct search key for dns_data.
		 * zone_name(a space)host_name
		 */
		strcpy(dns_key.data, zone);
		strcat(dns_key.data, " ");
		strncat(dns_key.data, xfr_data.data, xfr_data.size);

		dns_flags = DB_SET;

		while ((bdbhptres = dns_cursor->c_get(dns_cursor, &dns_key,
						      &dns_data,
						      dns_flags)) == 0) {

			dns_flags = DB_NEXT_DUP;

			/* +1 to allow for null term at end of string. */
			tmp = realloc(tmp, dns_data.size + 1);
			if (tmp == NULL)
				goto allnodes_cleanup;

			/* copy data to tmp string, and append null term. */
			strncpy(tmp, dns_data.data, dns_data.size);
			tmp[dns_data.size] = '\0';

			/* split string into dns data parts. */
			if (bdbhpt_parse_data(tmp, &pd) != ISC_R_SUCCESS)
				goto allnodes_cleanup;

			result = dns_sdlz_putnamedrr(allnodes, pd.host,
						     pd.type, pd.ttl, pd.data);
			if (result != ISC_R_SUCCESS)
				goto allnodes_cleanup;

		}  /* end inner while loop */

		/* clean up memory */
		if (tmp_zone_host != NULL) {
			free(tmp_zone_host);
			tmp_zone_host = NULL;
		}
	} /* end outer while loop */

 allnodes_cleanup:

	/* free any memory */
	if (tmp != NULL)
		free(tmp);

	if (tmp_zone_host != NULL)
		free(tmp_zone_host);

	if (tmp_zone != NULL)
		free(tmp_zone);

	/* get rid of cursors */
	if (xfr_cursor != NULL)
		xfr_cursor->c_close(xfr_cursor);

	if (dns_cursor != NULL)
		dns_cursor->c_close(dns_cursor);

	return result;
}

/*%
 * Performs bdbhpt cleanup.
 * Used by bdbhpt_create if there is an error starting up.
 * Used by bdbhpt_destroy when the driver is shutting down.
 */

static void
bdbhpt_cleanup(bdbhpt_instance_t *db) {

	isc_mem_t *mctx;

	/* close databases */
	if (db->data != NULL)
		db->data->close(db->data, 0);
	if (db->xfr != NULL)
		db->xfr->close(db->xfr, 0);
	if (db->zone != NULL)
		db->zone->close(db->zone, 0);
	if (db->client != NULL)
		db->client->close(db->client, 0);

	/* close environment */
	if (db->dbenv != NULL)
		db->dbenv->close(db->dbenv, 0);

	/* cleanup memory */
	if (db->mctx != NULL) {
		/* save mctx for later */
		mctx = db->mctx;
		/* return, and detach the memory */
		isc_mem_put(mctx, db, sizeof(bdbhpt_instance_t));
		isc_mem_detach(&mctx);
	}
}

static isc_result_t
bdbhpt_findzone(void *driverarg, void *dbdata, const char *name,
		dns_clientinfomethods_t *methods, dns_clientinfo_t *clientinfo)
{

	isc_result_t result;
	bdbhpt_instance_t *db = (bdbhpt_instance_t *) dbdata;
	DBT key, data;

	UNUSED(driverarg);
	UNUSED(methods);
	UNUSED(clientinfo);

	memset(&key, 0, sizeof(DBT));
	memset(&data, 0, sizeof(DBT));
	data.flags = DB_DBT_MALLOC;

	key.data = strdup(name);

	if (key.data == NULL)
		return (ISC_R_NOMEMORY);

	/*
	 * reverse string to take advantage of BDB locality of reference
	 * if we need futher lookups because the zone doesn't match the
	 * first time.
	 */
	key.data = bdbhpt_strrev(key.data);
	key.size = strlen(key.data);

	switch(db->zone->get(db->zone, NULL, &key, &data, 0)) {
	case DB_NOTFOUND:
		result = ISC_R_NOTFOUND;
		break;
	case 0:
		result = ISC_R_SUCCESS;
		break;
	default:
		result = ISC_R_FAILURE;
	}

	/* free any memory duplicate string in the key field */
	if (key.data != NULL)
		free(key.data);

	/* free any memory allocated to the data field. */
	if (data.data != NULL)
		free(data.data);

	return result;
}

static isc_result_t
bdbhpt_lookup(const char *zone, const char *name, void *driverarg,
	      void *dbdata, dns_sdlzlookup_t *lookup,
	      dns_clientinfomethods_t *methods, dns_clientinfo_t *clientinfo)
{

	isc_result_t result = ISC_R_NOTFOUND;
	bdbhpt_instance_t *db = (bdbhpt_instance_t *) dbdata;
	DBC *data_cursor = NULL;
	DBT key, data;
	int bdbhptres;
	int flags;

	bdbhpt_parsed_data_t pd;
	char *tmp = NULL;
	char *keyStr = NULL;

	UNUSED(driverarg);
	UNUSED(methods);
	UNUSED(clientinfo);

	memset(&key, 0, sizeof(DBT));
	memset(&data, 0, sizeof(DBT));

	key.size = strlen(zone) + strlen(name) + 1;

	/* allocate mem for key */
	key.data = keyStr = malloc((key.size + 1) * sizeof(char));

	if (keyStr == NULL)
		return ISC_R_NOMEMORY;

	strcpy(keyStr, zone);
	strcat(keyStr, " ");
	strcat(keyStr, name);

	/* get a cursor to loop through data */
	if (db->data->cursor(db->data, NULL, &data_cursor, 0) != 0) {
		result = ISC_R_FAILURE;
		goto lookup_cleanup;
	}

	result = ISC_R_NOTFOUND;

	flags = DB_SET;
	while ((bdbhptres = data_cursor->c_get(data_cursor, &key, &data,
					       flags)) == 0) {

		flags = DB_NEXT_DUP;
		tmp = realloc(tmp, data.size + 1);
		if (tmp == NULL)
			goto lookup_cleanup;

		strncpy(tmp, data.data, data.size);
		tmp[data.size] = '\0';

		if (bdbhpt_parse_data(tmp, &pd) != ISC_R_SUCCESS)
			goto lookup_cleanup;

		result = dns_sdlz_putrr(lookup, pd.type, pd.ttl, pd.data);

		if (result != ISC_R_SUCCESS)
			goto lookup_cleanup;
	} /* end while loop */

 lookup_cleanup:

	/* get rid of cursor */
	if (data_cursor != NULL)
		data_cursor->c_close(data_cursor);

	if (keyStr != NULL)
		free(keyStr);
	if (tmp != NULL)
		free(tmp);

	return result;
}

/*% Initializes, sets flags and then opens Berkeley databases. */

static isc_result_t
bdbhpt_opendb(DB_ENV *db_env, DBTYPE db_type, DB **db, const char *db_name,
	      char *db_file, int flags) {

	int result;

	/* Initialize the database. */
	if ((result = db_create(db, db_env, 0)) != 0) {
		isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
			      DNS_LOGMODULE_DLZ, ISC_LOG_ERROR,
			      "bdbhpt could not initialize %s database. "
			      "bdbhpt error: %s",
			      db_name, db_strerror(result));
		return ISC_R_FAILURE;
	}

	/* set database flags. */
	if ((result = (*db)->set_flags(*db, flags)) != 0) {
		isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
			      DNS_LOGMODULE_DLZ, ISC_LOG_ERROR,
			      "bdbhpt could not set flags for %s database. "
			      "bdbhpt error: %s",
			      db_name, db_strerror(result));
		return ISC_R_FAILURE;
	}

	/* open the database. */
	if ((result = (*db)->open(*db, NULL, db_file, db_name, db_type,
				  DB_RDONLY | bdbhpt_threads, 0)) != 0) {
		isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
			      DNS_LOGMODULE_DLZ, ISC_LOG_ERROR,
			      "bdbhpt could not open %s database in %s. "
			      "bdbhpt error: %s",
			      db_name, db_file, db_strerror(result));
		return ISC_R_FAILURE;
	}

	return ISC_R_SUCCESS;
}

static isc_result_t
bdbhpt_create(const char *dlzname, unsigned int argc, char *argv[],
	      void *driverarg, void **dbdata)
{
	isc_result_t result;
	int bdbhptres;
	int bdbFlags = 0;
	bdbhpt_instance_t *db = NULL;

	UNUSED(dlzname);
	UNUSED(driverarg);

	/* verify we have 4 arg's passed to the driver */
	if (argc != 4) {
		isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
			      DNS_LOGMODULE_DLZ, ISC_LOG_ERROR,
			      "bdbhpt driver requires at least "
			      "3 command line args.");
		return (ISC_R_FAILURE);
	}

	switch((char) *argv[1]) {
		/*
		 * Transactional mode.  Highest safety - lowest speed.
		 */
	case 'T':
	case 't':
		bdbFlags = DB_INIT_MPOOL | DB_INIT_LOCK |
			   DB_INIT_LOG | DB_INIT_TXN;
		isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
			      DNS_LOGMODULE_DLZ, ISC_LOG_DEBUG(1),
			      "bdbhpt driver using transactional mode.");
		break;
		/*
		 * Concurrent mode.  Lower safety (no rollback) -
		 * higher speed.
		 */
	case 'C':
	case 'c':
		bdbFlags = DB_INIT_CDB | DB_INIT_MPOOL;
		isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
			      DNS_LOGMODULE_DLZ, ISC_LOG_DEBUG(1),
			      "bdbhpt driver using concurrent mode.");
		break;
		/*
		 * Private mode. No inter-process communication & no locking.
		 * Lowest saftey - highest speed.
		 */
	case 'P':
	case 'p':
		bdbFlags = DB_PRIVATE | DB_INIT_MPOOL;
		isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
			      DNS_LOGMODULE_DLZ, ISC_LOG_DEBUG(1),
			      "bdbhpt driver using private mode.");
		break;
	default:
		isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
			      DNS_LOGMODULE_DLZ, ISC_LOG_ERROR,
			      "bdbhpt driver requires the operating mode "
			      "be set to P or C or T.  You specified '%s'",
			      argv[1]);
		return (ISC_R_FAILURE);
	}

	/* allocate and zero memory for driver structure */
	db = isc_mem_get(ns_g_mctx, sizeof(bdbhpt_instance_t));
	if (db == NULL) {
		isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
			      DNS_LOGMODULE_DLZ, ISC_LOG_ERROR,
			      "Could not allocate memory for "
			      "database instance object.");
		return (ISC_R_NOMEMORY);
	}
	memset(db, 0, sizeof(bdbhpt_instance_t));

	/* attach to the memory context */
	isc_mem_attach(ns_g_mctx, &db->mctx);

	/*
	 * create bdbhpt environment
	 * Basically bdbhpt allocates and assigns memory to db->dbenv
	 */
	bdbhptres = db_env_create(&db->dbenv, 0);
	if (bdbhptres != 0) {
		isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
			      DNS_LOGMODULE_DLZ, ISC_LOG_ERROR,
			      "bdbhpt environment could not be created. "
			      "bdbhpt error: %s",
			      db_strerror(bdbhptres));
		result = ISC_R_FAILURE;
		goto init_cleanup;
	}

	/* open bdbhpt environment */
	bdbhptres = db->dbenv->open(db->dbenv, argv[2],
				    bdbFlags | bdbhpt_threads | DB_CREATE, 0);
	if (bdbhptres != 0) {
		isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
			      DNS_LOGMODULE_DLZ, ISC_LOG_ERROR,
			      "bdbhpt environment at '%s' could not be opened."
			      " bdbhpt error: %s",
			      argv[2], db_strerror(bdbhptres));
		result = ISC_R_FAILURE;
		goto init_cleanup;
	}

	/* open dlz_data database. */
	result = bdbhpt_opendb(db->dbenv, DB_UNKNOWN, &db->data,
			       dlz_data, argv[3], DB_DUP | DB_DUPSORT);
	if (result != ISC_R_SUCCESS)
		goto init_cleanup;

	/* open dlz_xfr database. */
	result = bdbhpt_opendb(db->dbenv, DB_UNKNOWN, &db->xfr,
			       dlz_xfr, argv[3], DB_DUP | DB_DUPSORT);
	if (result != ISC_R_SUCCESS)
		goto init_cleanup;

	/* open dlz_zone database. */
	result = bdbhpt_opendb(db->dbenv, DB_UNKNOWN, &db->zone,
			       dlz_zone, argv[3], 0);
	if (result != ISC_R_SUCCESS)
		goto init_cleanup;

	/* open dlz_client database. */
	result = bdbhpt_opendb(db->dbenv, DB_UNKNOWN, &db->client,
			       dlz_client, argv[3], DB_DUP | DB_DUPSORT);
	if (result != ISC_R_SUCCESS)
		goto init_cleanup;

	*dbdata = db;

	return(ISC_R_SUCCESS);

 init_cleanup:

	bdbhpt_cleanup(db);
	return result;
}

static void
bdbhpt_destroy(void *driverarg, void *dbdata)
{
	UNUSED(driverarg);

	bdbhpt_cleanup((bdbhpt_instance_t *) dbdata);
}

/*
 * bdbhpt_authority not needed as authority data is returned by lookup
 */
static dns_sdlzmethods_t dlz_bdbhpt_methods = {
	bdbhpt_create,
	bdbhpt_destroy,
	bdbhpt_findzone,
	bdbhpt_lookup,
	NULL,
	bdbhpt_allnodes,
	bdbhpt_allowzonexfr,
	NULL,
	NULL,
	NULL,
	NULL,
	NULL,
	NULL,
	NULL,
};

/*%
 * Wrapper around dns_sdlzregister().
 */
isc_result_t
dlz_bdbhpt_init(void) {
	isc_result_t result;

	/*
	 * Write debugging message to log
	 */
	isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
		      DNS_LOGMODULE_DLZ, ISC_LOG_DEBUG(2),
		      "Registering DLZ bdbhpt driver.");

	result = dns_sdlzregister("bdbhpt", &dlz_bdbhpt_methods, NULL,
				  DNS_SDLZFLAG_RELATIVEOWNER |
				  DNS_SDLZFLAG_RELATIVERDATA |
				  DNS_SDLZFLAG_THREADSAFE,
				  ns_g_mctx, &dlz_bdbhpt);
	if (result != ISC_R_SUCCESS) {
		UNEXPECTED_ERROR(__FILE__, __LINE__,
				 "dns_sdlzregister() failed: %s",
				 isc_result_totext(result));
		result = ISC_R_UNEXPECTED;
	}


	return result;
}

/*%
 * Wrapper around dns_sdlzunregister().
 */
void
dlz_bdbhpt_clear(void) {

	/*
	 * Write debugging message to log
	 */
	isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
		      DNS_LOGMODULE_DLZ, ISC_LOG_DEBUG(2),
		      "Unregistering DLZ bdbhpt driver.");

	if (dlz_bdbhpt != NULL)
		dns_sdlzunregister(&dlz_bdbhpt);
}

#endif
