lib/dns/zt.c

	zt.c revision 0c27b3fe77ac1d5094ba3521e8142d9e7973133f
/*
 * Copyright (C) 1999-2002, 2004-2007, 2011-2016  Internet Systems Consortium, Inc. ("ISC")
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 */

/* $Id$ */

/*! \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, const 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));

    INSIST(zt->references > 0);
    zt->references++;
    zt->loads_pending++;

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