lib/dns/zt.c

	zt.c revision 92ef1a9b9dbd48ecb507b42ac62c15afefdaf838
/*
 * 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.
 */

/* $Id: zt.c,v 1.33 2001/06/04 19:33:19 tale Exp $ */

#include <config.h>

#include <isc/magic.h>
#include <isc/mem.h>
#include <isc/util.h>

#include <dns/rbt.h>
#include <dns/result.h>
#include <dns/zone.h>
#include <dns/zt.h>

struct dns_zt {
    /* Unlocked. */
    unsigned int        magic;
    isc_mem_t       *mctx;
    dns_rdataclass_t    rdclass;
    isc_rwlock_t        rwlock;
    /* Locked by lock. */
    isc_uint32_t        references;
    dns_rbt_t       *table;
};

#define ZTMAGIC         ISC_MAGIC('Z', 'T', 'b', 'l')
#define VALID_ZT(zt)        ISC_MAGIC_VALID(zt, ZTMAGIC)

static void
auto_detach(void *, void *);

static isc_result_t
load(dns_zone_t *zone, void *uap);

static isc_result_t
loadnew(dns_zone_t *zone, void *uap);

isc_result_t
dns_zt_create(isc_mem_t *mctx, dns_rdataclass_t rdclass, dns_zt_t **ztp) {
    dns_zt_t *zt;
    isc_result_t result;

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

    zt = isc_mem_get(mctx, sizeof *zt);
    if (zt == NULL)
        return (ISC_R_NOMEMORY);

    zt->table = NULL;
    result = dns_rbt_create(mctx, auto_detach, zt, &zt->table);
    if (result != ISC_R_SUCCESS)
        goto cleanup_zt;

    result = isc_rwlock_init(&zt->rwlock, 0, 0);
    if (result != ISC_R_SUCCESS) {
        UNEXPECTED_ERROR(__FILE__, __LINE__,
                 "isc_rwlock_init() failed: %s",
                 isc_result_totext(result));
        result = ISC_R_UNEXPECTED;
        goto cleanup_rbt;
    }

    zt->mctx = mctx;
    zt->references = 1;
    zt->rdclass = rdclass;
    zt->magic = ZTMAGIC;
    *ztp = zt;

    return (ISC_R_SUCCESS);

   cleanup_rbt:
    dns_rbt_destroy(&zt->table);

   cleanup_zt:
    isc_mem_put(mctx, zt, sizeof *zt);

    return (result);
}

isc_result_t
dns_zt_mount(dns_zt_t *zt, dns_zone_t *zone) {
    isc_result_t result;
    dns_zone_t *dummy = NULL;
    dns_name_t *name;

    REQUIRE(VALID_ZT(zt));

    name = dns_zone_getorigin(zone);

    RWLOCK(&zt->rwlock, isc_rwlocktype_write);

    result = dns_rbt_addname(zt->table, name, zone);
    if (result == ISC_R_SUCCESS)
        dns_zone_attach(zone, &dummy);

    RWUNLOCK(&zt->rwlock, isc_rwlocktype_write);

    return (result);
}

isc_result_t
dns_zt_unmount(dns_zt_t *zt, dns_zone_t *zone) {
    isc_result_t result;
    dns_name_t *name;

    REQUIRE(VALID_ZT(zt));

    name = dns_zone_getorigin(zone);

    RWLOCK(&zt->rwlock, isc_rwlocktype_write);

    result = dns_rbt_deletename(zt->table, name, ISC_FALSE);

    RWUNLOCK(&zt->rwlock, isc_rwlocktype_write);

    return (result);
}

isc_result_t
dns_zt_find(dns_zt_t *zt, dns_name_t *name, unsigned int options,
        dns_name_t *foundname, dns_zone_t **zonep)
{
    isc_result_t result;
    dns_zone_t *dummy = NULL;
    unsigned int rbtoptions = 0;

    REQUIRE(VALID_ZT(zt));

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

    RWLOCK(&zt->rwlock, isc_rwlocktype_read);

    result = dns_rbt_findname(zt->table, name, rbtoptions, foundname,
                  (void **)&dummy);
    if (result == ISC_R_SUCCESS || result == DNS_R_PARTIALMATCH)
        dns_zone_attach(dummy, zonep);

    RWUNLOCK(&zt->rwlock, isc_rwlocktype_read);

    return (result);
}

void
dns_zt_attach(dns_zt_t *zt, dns_zt_t **ztp) {

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

    RWLOCK(&zt->rwlock, isc_rwlocktype_write);

    INSIST(zt->references > 0);
    zt->references++;
    INSIST(zt->references != 0);

    RWUNLOCK(&zt->rwlock, isc_rwlocktype_write);

    *ztp = zt;
}

static isc_result_t
flush(dns_zone_t *zone, void *uap) {
    UNUSED(uap);
    return (dns_zone_flush(zone));
}

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;
}

void
dns_zt_flushanddetach(dns_zt_t **ztp) {
    zt_flushanddetach(ztp, ISC_TRUE);
}

void
dns_zt_detach(dns_zt_t **ztp) {
    zt_flushanddetach(ztp, ISC_FALSE);
}

isc_result_t
dns_zt_load(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, load, NULL);
    RWUNLOCK(&zt->rwlock, isc_rwlocktype_read);
    return (result);
}

static isc_result_t
load(dns_zone_t *zone, void *uap) {
    UNUSED(uap);
    return (dns_zone_load(zone));
}

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);
}

static isc_result_t
loadnew(dns_zone_t *zone, void *uap) {
    UNUSED(uap);
    return (dns_zone_loadnew(zone));
}

isc_result_t
dns_zt_apply(dns_zt_t *zt, isc_boolean_t stop,
         isc_result_t (*action)(dns_zone_t *, void *), void *uap)
{
    dns_rbtnode_t *node;
    dns_rbtnodechain_t chain;
    isc_result_t result;
    dns_zone_t *zone;

    REQUIRE(VALID_ZT(zt));
    REQUIRE(action != NULL);

    dns_rbtnodechain_init(&chain, zt->mctx);
    result = dns_rbtnodechain_first(&chain, zt->table, NULL, NULL);
    if (result == ISC_R_NOTFOUND) {
        /*
         * The tree is empty.
         */
        result = ISC_R_NOMORE;
    }
    while (result == DNS_R_NEWORIGIN || result == ISC_R_SUCCESS) {
        result = dns_rbtnodechain_current(&chain, NULL, NULL,
                          &node);
        if (result == ISC_R_SUCCESS) {
            zone = node->data;
            if (zone != NULL)
                result = (action)(zone, uap);
            if (result != ISC_R_SUCCESS && stop)
                goto cleanup;   /* don't break */
        }
        result = dns_rbtnodechain_next(&chain, NULL, NULL);
    }
    if (result == ISC_R_NOMORE)
        result = ISC_R_SUCCESS;

 cleanup:
    dns_rbtnodechain_invalidate(&chain);

    return (result);
}

/***
 *** Private
 ***/

static void
auto_detach(void *data, void *arg) {
    dns_zone_t *zone = data;

    UNUSED(arg);

    dns_zone_detach(&zone);
}