zt.c

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/*
 * Copyright (C) 2004-2007, 2011-2014  Internet Systems Consortium, Inc. ("ISC")
 * Copyright (C) 1999-2002  Internet Software Consortium.
 *
 * Permission to use, copy, modify, and/or 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.
 */

/* $Id$ */

/*! \file */

#include <config.h>

#include <isc/file.h>
#include <isc/magic.h>
#include <isc/mem.h>
#include <isc/string.h>
#include <isc/task.h>
#include <isc/util.h>

#include <dns/log.h>
#include <dns/name.h>
#include <dns/rbt.h>
#include <dns/rdataclass.h>
#include <dns/result.h>
#include <dns/view.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;
        dns_zt_allloaded_t      loaddone;
        void *                  loaddone_arg;
        /* Locked by lock. */
        isc_boolean_t           flush;
        isc_uint32_t            references;
        unsigned int            loads_pending;
        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
asyncload(dns_zone_t *zone, void *callback);

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

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

static isc_result_t
doneloading(dns_zt_t *zt, dns_zone_t *zone, isc_task_t *task);

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)
                goto cleanup_rbt;

        zt->mctx = NULL;
        isc_mem_attach(mctx, &zt->mctx);
        zt->references = 1;
        zt->flush = ISC_FALSE;
        zt->rdclass = rdclass;
        zt->magic = ZTMAGIC;
        zt->loaddone = NULL;
        zt->loaddone_arg = NULL;
        zt->loads_pending = 0;
        *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 **) (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_destroy(dns_zt_t *zt) {
        if (zt->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_putanddetach(&zt->mctx, zt, sizeof(*zt));
}

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_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) {
        isc_result_t result;
        UNUSED(uap);

        result = dns_zone_load(zone);
        if (result == DNS_R_CONTINUE || result == DNS_R_UPTODATE)
                result = ISC_R_SUCCESS;

        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);
}

/*
 * Initiates asynchronous loading of zone 'zone'.  'callback' is a
 * pointer to a function which will be used to inform the caller when
 * the zone loading is complete.
 */
static isc_result_t
asyncload(dns_zone_t *zone, void *callback) {
        isc_result_t result;
        dns_zt_zoneloaded_t *loaded = callback;
        dns_zt_t *zt;

        REQUIRE(zone != NULL);
        zt = dns_zone_getview(zone)->zonetable;
        INSIST(VALID_ZT(zt));

        result = dns_zone_asyncload(zone, *loaded, zt);
        if (result == ISC_R_SUCCESS) {
                INSIST(zt->references > 0);
                zt->references++;
                INSIST(zt->references != 0);
                zt->loads_pending++;
        }
        return (ISC_R_SUCCESS);
}

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) {
        isc_result_t result;
        UNUSED(uap);

        result = dns_zone_loadnew(zone);
        if (result == DNS_R_CONTINUE || result == DNS_R_UPTODATE ||
            result == DNS_R_DYNAMIC)
                result = ISC_R_SUCCESS;
        return (result);
}

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);
        if (tresult == ISC_R_NOTFOUND)
                tresult = ISC_R_SUCCESS;
        return ((result == ISC_R_SUCCESS) ? tresult : result);
}

static isc_result_t
freezezones(dns_zone_t *zone, void *uap) {
        isc_boolean_t freeze = *(isc_boolean_t *)uap;
        isc_boolean_t frozen;
        isc_result_t result = ISC_R_SUCCESS;
        char classstr[DNS_RDATACLASS_FORMATSIZE];
        char zonename[DNS_NAME_FORMATSIZE];
        dns_zone_t *raw = NULL;
        dns_view_t *view;
        const char *vname;
        const char *sep;
        int level;

        dns_zone_getraw(zone, &raw);
        if (raw != NULL)
                zone = raw;
        if (dns_zone_gettype(zone) != dns_zone_master) {
                if (raw != NULL)
                        dns_zone_detach(&raw);
                return (ISC_R_SUCCESS);
        }
        if (!dns_zone_isdynamic(zone, ISC_TRUE)) {
                if (raw != NULL)
                        dns_zone_detach(&raw);
                return (ISC_R_SUCCESS);
        }

        frozen = dns_zone_getupdatedisabled(zone);
        if (freeze) {
                if (frozen)
                        result = DNS_R_FROZEN;
                if (result == ISC_R_SUCCESS)
                        result = dns_zone_flush(zone);
                if (result == ISC_R_SUCCESS)
                        dns_zone_setupdatedisabled(zone, freeze);
        } else {
                if (frozen) {
                        result = dns_zone_loadandthaw(zone);
                        if (result == DNS_R_CONTINUE ||
                            result == DNS_R_UPTODATE)
                                result = ISC_R_SUCCESS;
                }
        }
        view = dns_zone_getview(zone);
        if (strcmp(view->name, "_bind") == 0 ||
            strcmp(view->name, "_default") == 0)
        {
                vname = "";
                sep = "";
        } else {
                vname = view->name;
                sep = " ";
        }
        dns_rdataclass_format(dns_zone_getclass(zone), classstr,
                              sizeof(classstr));
        dns_name_format(dns_zone_getorigin(zone), zonename, sizeof(zonename));
        level = (result != ISC_R_SUCCESS) ? ISC_LOG_ERROR : ISC_LOG_DEBUG(1);
        isc_log_write(dns_lctx, DNS_LOGCATEGORY_GENERAL, DNS_LOGMODULE_ZONE,
                      level, "%s zone '%s/%s'%s%s: %s",
                      freeze ? "freezing" : "thawing",
                      zonename, classstr, sep, vname,
                      isc_result_totext(result));
        if (raw != NULL)
                dns_zone_detach(&raw);
        return (result);
}

isc_result_t
dns_zt_apply(dns_zt_t *zt, isc_boolean_t stop,
             isc_result_t (*action)(dns_zone_t *, void *), void *uap)
{
        return (dns_zt_apply2(zt, stop, NULL, action, uap));
}

isc_result_t
dns_zt_apply2(dns_zt_t *zt, isc_boolean_t stop, isc_result_t *sub,
              isc_result_t (*action)(dns_zone_t *, void *), void *uap)
{
        dns_rbtnode_t *node;
        dns_rbtnodechain_t chain;
        isc_result_t result, tresult = ISC_R_SUCCESS;
        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.
                 */
                tresult = result;
                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) {
                                tresult = result;
                                goto cleanup;   /* don't break */
                        } else if (result != ISC_R_SUCCESS &&
                                   tresult == ISC_R_SUCCESS)
                                tresult = result;
                }
                result = dns_rbtnodechain_next(&chain, NULL, NULL);
        }
        if (result == ISC_R_NOMORE)
                result = ISC_R_SUCCESS;

 cleanup:
        dns_rbtnodechain_invalidate(&chain);
        if (sub != NULL)
                *sub = tresult;

        return (result);
}

/*
 * 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);
}

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

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

        UNUSED(arg);
        dns_zone_detach(&zone);
}

---