masterdump.c

Go to the documentation of this file.

/*
 * Copyright (C) 2004-2009, 2011-2015  Internet Systems Consortium, Inc. ("ISC")
 * Copyright (C) 1999-2003  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 <stdlib.h>

#include <isc/event.h>
#include <isc/file.h>
#include <isc/magic.h>
#include <isc/mem.h>
#include <isc/print.h>
#include <isc/stdio.h>
#include <isc/string.h>
#include <isc/task.h>
#include <isc/time.h>
#include <isc/util.h>

#include <dns/db.h>
#include <dns/dbiterator.h>
#include <dns/events.h>
#include <dns/fixedname.h>
#include <dns/lib.h>
#include <dns/log.h>
#include <dns/master.h>
#include <dns/masterdump.h>
#include <dns/ncache.h>
#include <dns/rdata.h>
#include <dns/rdataclass.h>
#include <dns/rdataset.h>
#include <dns/rdatasetiter.h>
#include <dns/rdatatype.h>
#include <dns/result.h>
#include <dns/time.h>
#include <dns/ttl.h>

#define DNS_DCTX_MAGIC          ISC_MAGIC('D', 'c', 't', 'x')
#define DNS_DCTX_VALID(d)       ISC_MAGIC_VALID(d, DNS_DCTX_MAGIC)

#define RETERR(x) do { \
        isc_result_t _r = (x); \
        if (_r != ISC_R_SUCCESS) \
                return (_r); \
        } while (0)

#define CHECK(x) do { \
        if ((x) != ISC_R_SUCCESS) \
                goto cleanup; \
        } while (0)

struct dns_master_style {
        unsigned int flags;             /* DNS_STYLEFLAG_* */
        unsigned int ttl_column;
        unsigned int class_column;
        unsigned int type_column;
        unsigned int rdata_column;
        unsigned int line_length;
        unsigned int tab_width;
        unsigned int split_width;
};

/*%
 * The maximum length of the newline+indentation that is output
 * when inserting a line break in an RR.  This effectively puts an
 * upper limits on the value of "rdata_column", because if it is
 * very large, the tabs and spaces needed to reach it will not fit.
 */
#define DNS_TOTEXT_LINEBREAK_MAXLEN 100

/*%
 * Context structure for a masterfile dump in progress.
 */
typedef struct dns_totext_ctx {
        dns_master_style_t      style;
        isc_boolean_t           class_printed;
        char *                  linebreak;
        char                    linebreak_buf[DNS_TOTEXT_LINEBREAK_MAXLEN];
        dns_name_t *            origin;
        dns_name_t *            neworigin;
        dns_fixedname_t         origin_fixname;
        isc_uint32_t            current_ttl;
        isc_boolean_t           current_ttl_valid;
} dns_totext_ctx_t;

LIBDNS_EXTERNAL_DATA const dns_master_style_t
dns_master_style_keyzone = {
        DNS_STYLEFLAG_OMIT_OWNER |
        DNS_STYLEFLAG_OMIT_CLASS |
        DNS_STYLEFLAG_REL_OWNER |
        DNS_STYLEFLAG_REL_DATA |
        DNS_STYLEFLAG_OMIT_TTL |
        DNS_STYLEFLAG_TTL |
        DNS_STYLEFLAG_COMMENT |
        DNS_STYLEFLAG_RRCOMMENT |
        DNS_STYLEFLAG_MULTILINE |
        DNS_STYLEFLAG_KEYDATA,
        24, 24, 24, 32, 80, 8, UINT_MAX
};

LIBDNS_EXTERNAL_DATA const dns_master_style_t
dns_master_style_default = {
        DNS_STYLEFLAG_OMIT_OWNER |
        DNS_STYLEFLAG_OMIT_CLASS |
        DNS_STYLEFLAG_REL_OWNER |
        DNS_STYLEFLAG_REL_DATA |
        DNS_STYLEFLAG_OMIT_TTL |
        DNS_STYLEFLAG_TTL |
        DNS_STYLEFLAG_COMMENT |
        DNS_STYLEFLAG_RRCOMMENT |
        DNS_STYLEFLAG_MULTILINE,
        24, 24, 24, 32, 80, 8, UINT_MAX
};

LIBDNS_EXTERNAL_DATA const dns_master_style_t
dns_master_style_full = {
        DNS_STYLEFLAG_COMMENT |
        DNS_STYLEFLAG_RESIGN,
        46, 46, 46, 64, 120, 8, UINT_MAX
};

LIBDNS_EXTERNAL_DATA const dns_master_style_t
dns_master_style_explicitttl = {
        DNS_STYLEFLAG_OMIT_OWNER |
        DNS_STYLEFLAG_OMIT_CLASS |
        DNS_STYLEFLAG_REL_OWNER |
        DNS_STYLEFLAG_REL_DATA |
        DNS_STYLEFLAG_COMMENT |
        DNS_STYLEFLAG_RRCOMMENT |
        DNS_STYLEFLAG_MULTILINE,
        24, 32, 32, 40, 80, 8, UINT_MAX
};

LIBDNS_EXTERNAL_DATA const dns_master_style_t
dns_master_style_cache = {
        DNS_STYLEFLAG_OMIT_OWNER |
        DNS_STYLEFLAG_OMIT_CLASS |
        DNS_STYLEFLAG_MULTILINE |
        DNS_STYLEFLAG_RRCOMMENT |
        DNS_STYLEFLAG_TRUST |
        DNS_STYLEFLAG_NCACHE,
        24, 32, 32, 40, 80, 8, UINT_MAX
};

LIBDNS_EXTERNAL_DATA const dns_master_style_t
dns_master_style_simple = {
        0,
        24, 32, 32, 40, 80, 8, UINT_MAX
};

/*%
 * A style suitable for dns_rdataset_totext().
 */
LIBDNS_EXTERNAL_DATA const dns_master_style_t
dns_master_style_debug = {
        DNS_STYLEFLAG_REL_OWNER,
        24, 32, 40, 48, 80, 8, UINT_MAX
};

/*%
 * Similar, but with each line commented out.
 */
LIBDNS_EXTERNAL_DATA const dns_master_style_t
dns_master_style_comment = {
        DNS_STYLEFLAG_REL_OWNER |
        DNS_STYLEFLAG_MULTILINE |
        DNS_STYLEFLAG_RRCOMMENT |
        DNS_STYLEFLAG_COMMENTDATA,
        24, 32, 40, 48, 80, 8, UINT_MAX
};


#define N_SPACES 10
static char spaces[N_SPACES+1] = "          ";

#define N_TABS 10
static char tabs[N_TABS+1] = "\t\t\t\t\t\t\t\t\t\t";

struct dns_dumpctx {
        unsigned int            magic;
        isc_mem_t               *mctx;
        isc_mutex_t             lock;
        unsigned int            references;
        isc_boolean_t           canceled;
        isc_boolean_t           first;
        isc_boolean_t           do_date;
        isc_stdtime_t           now;
        FILE                    *f;
        dns_db_t                *db;
        dns_dbversion_t         *version;
        dns_dbiterator_t        *dbiter;
        dns_totext_ctx_t        tctx;
        isc_task_t              *task;
        dns_dumpdonefunc_t      done;
        void                    *done_arg;
        unsigned int            nodes;
        /* dns_master_dumpinc() */
        char                    *file;
        char                    *tmpfile;
        dns_masterformat_t      format;
        dns_masterrawheader_t   header;
        isc_result_t            (*dumpsets)(isc_mem_t *mctx, dns_name_t *name,
                                            dns_rdatasetiter_t *rdsiter,
                                            dns_totext_ctx_t *ctx,
                                            isc_buffer_t *buffer, FILE *f);
};

#define NXDOMAIN(x) (((x)->attributes & DNS_RDATASETATTR_NXDOMAIN) != 0)

/*%
 * Output tabs and spaces to go from column '*current' to
 * column 'to', and update '*current' to reflect the new
 * current column.
 */
static isc_result_t
indent(unsigned int *current, unsigned int to, int tabwidth,
       isc_buffer_t *target)
{
        isc_region_t r;
        unsigned char *p;
        unsigned int from;
        int ntabs, nspaces, t;

        from = *current;

        if (to < from + 1)
                to = from + 1;

        ntabs = to / tabwidth - from / tabwidth;
        if (ntabs < 0)
                ntabs = 0;

        if (ntabs > 0) {
                isc_buffer_availableregion(target, &r);
                if (r.length < (unsigned) ntabs)
                        return (ISC_R_NOSPACE);
                p = r.base;

                t = ntabs;
                while (t) {
                        int n = t;
                        if (n > N_TABS)
                                n = N_TABS;
                        memmove(p, tabs, n);
                        p += n;
                        t -= n;
                }
                isc_buffer_add(target, ntabs);
                from = (to / tabwidth) * tabwidth;
        }

        nspaces = to - from;
        INSIST(nspaces >= 0);

        isc_buffer_availableregion(target, &r);
        if (r.length < (unsigned) nspaces)
                return (ISC_R_NOSPACE);
        p = r.base;

        t = nspaces;
        while (t) {
                int n = t;
                if (n > N_SPACES)
                        n = N_SPACES;
                memmove(p, spaces, n);
                p += n;
                t -= n;
        }
        isc_buffer_add(target, nspaces);

        *current = to;
        return (ISC_R_SUCCESS);
}

static isc_result_t
totext_ctx_init(const dns_master_style_t *style, dns_totext_ctx_t *ctx) {
        isc_result_t result;

        REQUIRE(style->tab_width != 0);

        ctx->style = *style;
        ctx->class_printed = ISC_FALSE;

        dns_fixedname_init(&ctx->origin_fixname);

        /*
         * Set up the line break string if needed.
         */
        if ((ctx->style.flags & DNS_STYLEFLAG_MULTILINE) != 0) {
                isc_buffer_t buf;
                isc_region_t r;
                unsigned int col = 0;

                isc_buffer_init(&buf, ctx->linebreak_buf,
                                sizeof(ctx->linebreak_buf));

                isc_buffer_availableregion(&buf, &r);
                if (r.length < 1)
                        return (DNS_R_TEXTTOOLONG);
                r.base[0] = '\n';
                isc_buffer_add(&buf, 1);

                if ((ctx->style.flags & DNS_STYLEFLAG_COMMENTDATA) != 0) {
                        isc_buffer_availableregion(&buf, &r);
                        if (r.length < 1)
                                return (DNS_R_TEXTTOOLONG);
                        r.base[0] = ';';
                        isc_buffer_add(&buf, 1);
                }

                result = indent(&col, ctx->style.rdata_column,
                                ctx->style.tab_width, &buf);
                /*
                 * Do not return ISC_R_NOSPACE if the line break string
                 * buffer is too small, because that would just make
                 * dump_rdataset() retry indefinitely with ever
                 * bigger target buffers.  That's a different buffer,
                 * so it won't help.  Use DNS_R_TEXTTOOLONG as a substitute.
                 */
                if (result == ISC_R_NOSPACE)
                        return (DNS_R_TEXTTOOLONG);
                if (result != ISC_R_SUCCESS)
                        return (result);

                isc_buffer_availableregion(&buf, &r);
                if (r.length < 1)
                        return (DNS_R_TEXTTOOLONG);
                r.base[0] = '\0';
                isc_buffer_add(&buf, 1);
                ctx->linebreak = ctx->linebreak_buf;
        } else {
                ctx->linebreak = NULL;
        }

        ctx->origin = NULL;
        ctx->neworigin = NULL;
        ctx->current_ttl = 0;
        ctx->current_ttl_valid = ISC_FALSE;

        return (ISC_R_SUCCESS);
}

#define INDENT_TO(col) \
        do { \
                 if ((result = indent(&column, ctx->style.col, \
                                      ctx->style.tab_width, target)) \
                     != ISC_R_SUCCESS) \
                            return (result); \
        } while (0)


static isc_result_t
str_totext(const char *source, isc_buffer_t *target) {
        unsigned int l;
        isc_region_t region;

        isc_buffer_availableregion(target, &region);
        l = strlen(source);

        if (l > region.length)
                return (ISC_R_NOSPACE);

        memmove(region.base, source, l);
        isc_buffer_add(target, l);
        return (ISC_R_SUCCESS);
}

static isc_result_t
ncache_summary(dns_rdataset_t *rdataset, isc_boolean_t omit_final_dot,
               isc_buffer_t *target)
{
        isc_result_t result = ISC_R_SUCCESS;
        dns_rdataset_t rds;
        dns_name_t name;

        dns_rdataset_init(&rds);
        dns_name_init(&name, NULL);

        do {
                dns_ncache_current(rdataset, &name, &rds);
                for (result = dns_rdataset_first(&rds);
                     result == ISC_R_SUCCESS;
                     result = dns_rdataset_next(&rds)) {
                        CHECK(str_totext("; ", target));
                        CHECK(dns_name_totext(&name, omit_final_dot, target));
                        CHECK(str_totext(" ", target));
                        CHECK(dns_rdatatype_totext(rds.type, target));
                        if (rds.type == dns_rdatatype_rrsig) {
                                CHECK(str_totext(" ", target));
                                CHECK(dns_rdatatype_totext(rds.covers, target));
                                CHECK(str_totext(" ...\n", target));
                        } else {
                                dns_rdata_t rdata = DNS_RDATA_INIT;
                                dns_rdataset_current(&rds, &rdata);
                                CHECK(str_totext(" ", target));
                                CHECK(dns_rdata_tofmttext(&rdata, dns_rootname,
                                                          0, 0, 0, " ", target));
                                CHECK(str_totext("\n", target));
                        }
                }
                dns_rdataset_disassociate(&rds);
                result = dns_rdataset_next(rdataset);
        } while (result == ISC_R_SUCCESS);

        if (result == ISC_R_NOMORE)
                result = ISC_R_SUCCESS;
 cleanup:
        if (dns_rdataset_isassociated(&rds))
                dns_rdataset_disassociate(&rds);

        return (result);
}

/*
 * Convert 'rdataset' to master file text format according to 'ctx',
 * storing the result in 'target'.  If 'owner_name' is NULL, it
 * is omitted; otherwise 'owner_name' must be valid and have at least
 * one label.
 */

static isc_result_t
rdataset_totext(dns_rdataset_t *rdataset,
                dns_name_t *owner_name,
                dns_totext_ctx_t *ctx,
                isc_boolean_t omit_final_dot,
                isc_buffer_t *target)
{
        isc_result_t result;
        unsigned int column;
        isc_boolean_t first = ISC_TRUE;
        isc_uint32_t current_ttl;
        isc_boolean_t current_ttl_valid;
        dns_rdatatype_t type;
        unsigned int type_start;
        dns_fixedname_t fixed;
        dns_name_t *name = NULL;

        REQUIRE(DNS_RDATASET_VALID(rdataset));

        rdataset->attributes |= DNS_RDATASETATTR_LOADORDER;
        result = dns_rdataset_first(rdataset);

        current_ttl = ctx->current_ttl;
        current_ttl_valid = ctx->current_ttl_valid;

        if (owner_name != NULL) {
                dns_fixedname_init(&fixed);
                name = dns_fixedname_name(&fixed);
                dns_name_copy(owner_name, name, NULL);
                dns_rdataset_getownercase(rdataset, name);
        }

        while (result == ISC_R_SUCCESS) {
                column = 0;

                /*
                 * Comment?
                 */
                if ((ctx->style.flags & DNS_STYLEFLAG_COMMENTDATA) != 0)
                        RETERR(str_totext(";", target));

                /*
                 * Owner name.
                 */
                if (name != NULL &&
                    ! ((ctx->style.flags & DNS_STYLEFLAG_OMIT_OWNER) != 0 &&
                       !first))
                {
                        unsigned int name_start = target->used;
                        RETERR(dns_name_totext(name, omit_final_dot, target));
                        column += target->used - name_start;
                }

                /*
                 * TTL.
                 */
                if ((ctx->style.flags & DNS_STYLEFLAG_NO_TTL) == 0 &&
                    !((ctx->style.flags & DNS_STYLEFLAG_OMIT_TTL) != 0 &&
                      current_ttl_valid &&
                      rdataset->ttl == current_ttl))
                {
                        char ttlbuf[64];
                        isc_region_t r;
                        unsigned int length;

                        INDENT_TO(ttl_column);
                        if ((ctx->style.flags & DNS_STYLEFLAG_TTL_UNITS) != 0) {
                                length = target->used;
                                result = dns_ttl_totext2(rdataset->ttl,
                                                        ISC_FALSE, ISC_FALSE,
                                                        target);
                                if (result != ISC_R_SUCCESS)
                                        return (result);
                                column += target->used - length;
                        } else {
                                length = snprintf(ttlbuf, sizeof(ttlbuf), "%u",
                                                  rdataset->ttl);
                                INSIST(length <= sizeof(ttlbuf));
                                isc_buffer_availableregion(target, &r);
                                if (r.length < length)
                                        return (ISC_R_NOSPACE);
                                memmove(r.base, ttlbuf, length);
                                isc_buffer_add(target, length);
                                column += length;
                        }

                        /*
                         * If the $TTL directive is not in use, the TTL we
                         * just printed becomes the default for subsequent RRs.
                         */
                        if ((ctx->style.flags & DNS_STYLEFLAG_TTL) == 0) {
                                current_ttl = rdataset->ttl;
                                current_ttl_valid = ISC_TRUE;
                        }
                }

                /*
                 * Class.
                 */
                if ((ctx->style.flags & DNS_STYLEFLAG_NO_CLASS) == 0 &&
                    ((ctx->style.flags & DNS_STYLEFLAG_OMIT_CLASS) == 0 ||
                     ctx->class_printed == ISC_FALSE))
                {
                        unsigned int class_start;
                        INDENT_TO(class_column);
                        class_start = target->used;
                        result = dns_rdataclass_totext(rdataset->rdclass,
                                                       target);
                        if (result != ISC_R_SUCCESS)
                                return (result);
                        column += (target->used - class_start);
                }

                /*
                 * Type.
                 */

                if ((rdataset->attributes & DNS_RDATASETATTR_NEGATIVE) != 0) {
                        type = rdataset->covers;
                } else {
                        type = rdataset->type;
                }

                INDENT_TO(type_column);
                type_start = target->used;
                if ((rdataset->attributes & DNS_RDATASETATTR_NEGATIVE) != 0)
                        RETERR(str_totext("\\-", target));
                switch (type) {
                case dns_rdatatype_keydata:
#define KEYDATA "KEYDATA"
                        if ((ctx->style.flags & DNS_STYLEFLAG_KEYDATA) != 0) {
                                if (isc_buffer_availablelength(target) <
                                    (sizeof(KEYDATA) - 1))
                                        return (ISC_R_NOSPACE);
                                isc_buffer_putstr(target, KEYDATA);
                                break;
                        }
                        /* FALLTHROUGH */
                default:
                        result = dns_rdatatype_totext(type, target);
                        if (result != ISC_R_SUCCESS)
                                return (result);
                }
                column += (target->used - type_start);

                /*
                 * Rdata.
                 */
                INDENT_TO(rdata_column);
                if ((rdataset->attributes & DNS_RDATASETATTR_NEGATIVE) != 0) {
                        if (NXDOMAIN(rdataset))
                                RETERR(str_totext(";-$NXDOMAIN\n", target));
                        else
                                RETERR(str_totext(";-$NXRRSET\n", target));
                        /*
                         * Print a summary of the cached records which make
                         * up the negative response.
                         */
                        RETERR(ncache_summary(rdataset, omit_final_dot,
                                              target));
                        break;
                } else {
                        dns_rdata_t rdata = DNS_RDATA_INIT;
                        isc_region_t r;

                        dns_rdataset_current(rdataset, &rdata);

                        RETERR(dns_rdata_tofmttext(&rdata,
                                                   ctx->origin,
                                                   ctx->style.flags,
                                                   ctx->style.line_length -
                                                       ctx->style.rdata_column,
                                                   ctx->style.split_width,
                                                   ctx->linebreak,
                                                   target));

                        isc_buffer_availableregion(target, &r);
                        if (r.length < 1)
                                return (ISC_R_NOSPACE);
                        r.base[0] = '\n';
                        isc_buffer_add(target, 1);
                }

                first = ISC_FALSE;
                result = dns_rdataset_next(rdataset);
        }

        if (result != ISC_R_NOMORE)
                return (result);

        /*
         * Update the ctx state to reflect what we just printed.
         * This is done last, only when we are sure we will return
         * success, because this function may be called multiple
         * times with increasing buffer sizes until it succeeds,
         * and failed attempts must not update the state prematurely.
         */
        ctx->class_printed = ISC_TRUE;
        ctx->current_ttl= current_ttl;
        ctx->current_ttl_valid = current_ttl_valid;

        return (ISC_R_SUCCESS);
}

/*
 * Print the name, type, and class of an empty rdataset,
 * such as those used to represent the question section
 * of a DNS message.
 */
static isc_result_t
question_totext(dns_rdataset_t *rdataset,
                dns_name_t *owner_name,
                dns_totext_ctx_t *ctx,
                isc_boolean_t omit_final_dot,
                isc_buffer_t *target)
{
        unsigned int column;
        isc_result_t result;
        isc_region_t r;

        REQUIRE(DNS_RDATASET_VALID(rdataset));
        result = dns_rdataset_first(rdataset);
        REQUIRE(result == ISC_R_NOMORE);

        column = 0;

        /* Owner name */
        {
                unsigned int name_start = target->used;
                RETERR(dns_name_totext(owner_name,
                                       omit_final_dot,
                                       target));
                column += target->used - name_start;
        }

        /* Class */
        {
                unsigned int class_start;
                INDENT_TO(class_column);
                class_start = target->used;
                result = dns_rdataclass_totext(rdataset->rdclass, target);
                if (result != ISC_R_SUCCESS)
                        return (result);
                column += (target->used - class_start);
        }

        /* Type */
        {
                unsigned int type_start;
                INDENT_TO(type_column);
                type_start = target->used;
                result = dns_rdatatype_totext(rdataset->type, target);
                if (result != ISC_R_SUCCESS)
                        return (result);
                column += (target->used - type_start);
        }

        isc_buffer_availableregion(target, &r);
        if (r.length < 1)
                return (ISC_R_NOSPACE);
        r.base[0] = '\n';
        isc_buffer_add(target, 1);

        return (ISC_R_SUCCESS);
}

isc_result_t
dns_rdataset_totext(dns_rdataset_t *rdataset,
                    dns_name_t *owner_name,
                    isc_boolean_t omit_final_dot,
                    isc_boolean_t question,
                    isc_buffer_t *target)
{
        dns_totext_ctx_t ctx;
        isc_result_t result;
        result = totext_ctx_init(&dns_master_style_debug, &ctx);
        if (result != ISC_R_SUCCESS) {
                UNEXPECTED_ERROR(__FILE__, __LINE__,
                                 "could not set master file style");
                return (ISC_R_UNEXPECTED);
        }

        /*
         * The caller might want to give us an empty owner
         * name (e.g. if they are outputting into a master
         * file and this rdataset has the same name as the
         * previous one.)
         */
        if (dns_name_countlabels(owner_name) == 0)
                owner_name = NULL;

        if (question)
                return (question_totext(rdataset, owner_name, &ctx,
                                        omit_final_dot, target));
        else
                return (rdataset_totext(rdataset, owner_name, &ctx,
                                        omit_final_dot, target));
}

isc_result_t
dns_master_rdatasettotext(dns_name_t *owner_name,
                          dns_rdataset_t *rdataset,
                          const dns_master_style_t *style,
                          isc_buffer_t *target)
{
        dns_totext_ctx_t ctx;
        isc_result_t result;
        result = totext_ctx_init(style, &ctx);
        if (result != ISC_R_SUCCESS) {
                UNEXPECTED_ERROR(__FILE__, __LINE__,
                                 "could not set master file style");
                return (ISC_R_UNEXPECTED);
        }

        return (rdataset_totext(rdataset, owner_name, &ctx,
                                ISC_FALSE, target));
}

isc_result_t
dns_master_questiontotext(dns_name_t *owner_name,
                          dns_rdataset_t *rdataset,
                          const dns_master_style_t *style,
                          isc_buffer_t *target)
{
        dns_totext_ctx_t ctx;
        isc_result_t result;
        result = totext_ctx_init(style, &ctx);
        if (result != ISC_R_SUCCESS) {
                UNEXPECTED_ERROR(__FILE__, __LINE__,
                                 "could not set master file style");
                return (ISC_R_UNEXPECTED);
        }

        return (question_totext(rdataset, owner_name, &ctx,
                                ISC_FALSE, target));
}

/*
 * Print an rdataset.  'buffer' is a scratch buffer, which must have been
 * dynamically allocated by the caller.  It must be large enough to
 * hold the result from dns_ttl_totext().  If more than that is needed,
 * the buffer will be grown automatically.
 */

static isc_result_t
dump_rdataset(isc_mem_t *mctx, dns_name_t *name, dns_rdataset_t *rdataset,
              dns_totext_ctx_t *ctx,
              isc_buffer_t *buffer, FILE *f)
{
        isc_region_t r;
        isc_result_t result;

        REQUIRE(buffer->length > 0);

        /*
         * Output a $TTL directive if needed.
         */

        if ((ctx->style.flags & DNS_STYLEFLAG_TTL) != 0) {
                if (ctx->current_ttl_valid == ISC_FALSE ||
                    ctx->current_ttl != rdataset->ttl)
                {
                        if ((ctx->style.flags & DNS_STYLEFLAG_COMMENT) != 0)
                        {
                                isc_buffer_clear(buffer);
                                result = dns_ttl_totext(rdataset->ttl,
                                                        ISC_TRUE, buffer);
                                INSIST(result == ISC_R_SUCCESS);
                                isc_buffer_usedregion(buffer, &r);
                                fprintf(f, "$TTL %u\t; %.*s\n", rdataset->ttl,
                                        (int) r.length, (char *) r.base);
                        } else {
                                fprintf(f, "$TTL %u\n", rdataset->ttl);
                        }
                        ctx->current_ttl = rdataset->ttl;
                        ctx->current_ttl_valid = ISC_TRUE;
                }
        }

        isc_buffer_clear(buffer);

        /*
         * Generate the text representation of the rdataset into
         * the buffer.  If the buffer is too small, grow it.
         */
        for (;;) {
                int newlength;
                void *newmem;
                result = rdataset_totext(rdataset, name, ctx,
                                         ISC_FALSE, buffer);
                if (result != ISC_R_NOSPACE)
                        break;

                newlength = buffer->length * 2;
                newmem = isc_mem_get(mctx, newlength);
                if (newmem == NULL)
                        return (ISC_R_NOMEMORY);
                isc_mem_put(mctx, buffer->base, buffer->length);
                isc_buffer_init(buffer, newmem, newlength);
        }
        if (result != ISC_R_SUCCESS)
                return (result);

        /*
         * Write the buffer contents to the master file.
         */
        isc_buffer_usedregion(buffer, &r);
        result = isc_stdio_write(r.base, 1, (size_t)r.length, f, NULL);

        if (result != ISC_R_SUCCESS) {
                UNEXPECTED_ERROR(__FILE__, __LINE__,
                                 "master file write failed: %s",
                                 isc_result_totext(result));
                return (result);
        }

        return (ISC_R_SUCCESS);
}

/*
 * Define the order in which rdatasets should be printed in zone
 * files.  We will print SOA and NS records before others, SIGs
 * immediately following the things they sign, and order everything
 * else by RR number.  This is all just for aesthetics and
 * compatibility with buggy software that expects the SOA to be first;
 * the DNS specifications allow any order.
 */

static int
dump_order(const dns_rdataset_t *rds) {
        int t;
        int sig;
        if (rds->type == dns_rdatatype_rrsig) {
                t = rds->covers;
                sig = 1;
        } else {
                t = rds->type;
                sig = 0;
        }
        switch (t) {
        case dns_rdatatype_soa:
                t = 0;
                break;
        case dns_rdatatype_ns:
                t = 1;
                break;
        default:
                t += 2;
                break;
        }
        return (t << 1) + sig;
}

static int
dump_order_compare(const void *a, const void *b) {
        return (dump_order(*((const dns_rdataset_t * const *) a)) -
                dump_order(*((const dns_rdataset_t * const *) b)));
}

/*
 * Dump all the rdatasets of a domain name to a master file.  We make
 * a "best effort" attempt to sort the RRsets in a nice order, but if
 * there are more than MAXSORT RRsets, we punt and only sort them in
 * groups of MAXSORT.  This is not expected to ever happen in practice
 * since much less than 64 RR types have been registered with the
 * IANA, so far, and the output will be correct (though not
 * aesthetically pleasing) even if it does happen.
 */

#define MAXSORT 64

static isc_result_t
dump_rdatasets_text(isc_mem_t *mctx, dns_name_t *name,
                    dns_rdatasetiter_t *rdsiter, dns_totext_ctx_t *ctx,
                    isc_buffer_t *buffer, FILE *f)
{
        isc_result_t itresult, dumpresult;
        isc_region_t r;
        dns_rdataset_t rdatasets[MAXSORT];
        dns_rdataset_t *sorted[MAXSORT];
        int i, n;

        itresult = dns_rdatasetiter_first(rdsiter);
        dumpresult = ISC_R_SUCCESS;

        if (itresult == ISC_R_SUCCESS && ctx->neworigin != NULL) {
                isc_buffer_clear(buffer);
                itresult = dns_name_totext(ctx->neworigin, ISC_FALSE, buffer);
                RUNTIME_CHECK(itresult == ISC_R_SUCCESS);
                isc_buffer_usedregion(buffer, &r);
                fprintf(f, "$ORIGIN %.*s\n", (int) r.length, (char *) r.base);
                ctx->neworigin = NULL;
        }

 again:
        for (i = 0;
             itresult == ISC_R_SUCCESS && i < MAXSORT;
             itresult = dns_rdatasetiter_next(rdsiter), i++) {
                dns_rdataset_init(&rdatasets[i]);
                dns_rdatasetiter_current(rdsiter, &rdatasets[i]);
                sorted[i] = &rdatasets[i];
        }
        n = i;
        INSIST(n <= MAXSORT);

        qsort(sorted, n, sizeof(sorted[0]), dump_order_compare);

        for (i = 0; i < n; i++) {
                dns_rdataset_t *rds = sorted[i];
                if (ctx->style.flags & DNS_STYLEFLAG_TRUST)
                        fprintf(f, "; %s\n", dns_trust_totext(rds->trust));
                if (((rds->attributes & DNS_RDATASETATTR_NEGATIVE) != 0) &&
                    (ctx->style.flags & DNS_STYLEFLAG_NCACHE) == 0) {
                        /* Omit negative cache entries */
                } else {
                        isc_result_t result =
                                dump_rdataset(mctx, name, rds, ctx,
                                               buffer, f);
                        if (result != ISC_R_SUCCESS)
                                dumpresult = result;
                        if ((ctx->style.flags & DNS_STYLEFLAG_OMIT_OWNER) != 0)
                                name = NULL;
                }
                if (ctx->style.flags & DNS_STYLEFLAG_RESIGN &&
                    rds->attributes & DNS_RDATASETATTR_RESIGN) {
                        isc_buffer_t b;
                        char buf[sizeof("YYYYMMDDHHMMSS")];
                        memset(buf, 0, sizeof(buf));
                        isc_buffer_init(&b, buf, sizeof(buf) - 1);
                        dns_time64_totext((isc_uint64_t)rds->resign, &b);
                        fprintf(f, "; resign=%s\n", buf);
                }
                dns_rdataset_disassociate(rds);
        }

        if (dumpresult != ISC_R_SUCCESS)
                return (dumpresult);

        /*
         * If we got more data than could be sorted at once,
         * go handle the rest.
         */
        if (itresult == ISC_R_SUCCESS)
                goto again;

        if (itresult == ISC_R_NOMORE)
                itresult = ISC_R_SUCCESS;

        return (itresult);
}

/*
 * Dump given RRsets in the "raw" format.
 */
static isc_result_t
dump_rdataset_raw(isc_mem_t *mctx, dns_name_t *name, dns_rdataset_t *rdataset,
                  isc_buffer_t *buffer, FILE *f)
{
        isc_result_t result;
        isc_uint32_t totallen;
        isc_uint16_t dlen;
        isc_region_t r, r_hdr;

        REQUIRE(buffer->length > 0);
        REQUIRE(DNS_RDATASET_VALID(rdataset));

        rdataset->attributes |= DNS_RDATASETATTR_LOADORDER;
 restart:
        totallen = 0;
        result = dns_rdataset_first(rdataset);
        REQUIRE(result == ISC_R_SUCCESS);

        isc_buffer_clear(buffer);

        /*
         * Common header and owner name (length followed by name)
         * These fields should be in a moderate length, so we assume we
         * can store all of them in the initial buffer.
         */
        isc_buffer_availableregion(buffer, &r_hdr);
        INSIST(r_hdr.length >= sizeof(dns_masterrawrdataset_t));
        isc_buffer_putuint32(buffer, totallen); /* XXX: leave space */
        isc_buffer_putuint16(buffer, rdataset->rdclass); /* 16-bit class */
        isc_buffer_putuint16(buffer, rdataset->type); /* 16-bit type */
        isc_buffer_putuint16(buffer, rdataset->covers); /* same as type */
        isc_buffer_putuint32(buffer, rdataset->ttl); /* 32-bit TTL */
        isc_buffer_putuint32(buffer, dns_rdataset_count(rdataset));
        totallen = isc_buffer_usedlength(buffer);
        INSIST(totallen <= sizeof(dns_masterrawrdataset_t));

        dns_name_toregion(name, &r);
        INSIST(isc_buffer_availablelength(buffer) >=
               (sizeof(dlen) + r.length));
        dlen = (isc_uint16_t)r.length;
        isc_buffer_putuint16(buffer, dlen);
        isc_buffer_copyregion(buffer, &r);
        totallen += sizeof(dlen) + r.length;

        do {
                dns_rdata_t rdata = DNS_RDATA_INIT;

                dns_rdataset_current(rdataset, &rdata);
                dns_rdata_toregion(&rdata, &r);
                INSIST(r.length <= 0xffffU);
                dlen = (isc_uint16_t)r.length;

                /*
                 * Copy the rdata into the buffer.  If the buffer is too small,
                 * grow it.  This should be rare, so we'll simply restart the
                 * entire procedure (or should we copy the old data and
                 * continue?).
                 */
                if (isc_buffer_availablelength(buffer) <
                                                 sizeof(dlen) + r.length) {
                        int newlength;
                        void *newmem;

                        newlength = buffer->length * 2;
                        newmem = isc_mem_get(mctx, newlength);
                        if (newmem == NULL)
                                return (ISC_R_NOMEMORY);
                        isc_mem_put(mctx, buffer->base, buffer->length);
                        isc_buffer_init(buffer, newmem, newlength);
                        goto restart;
                }
                isc_buffer_putuint16(buffer, dlen);
                isc_buffer_copyregion(buffer, &r);
                totallen += sizeof(dlen) + r.length;

                result = dns_rdataset_next(rdataset);
        } while (result == ISC_R_SUCCESS);

        if (result != ISC_R_NOMORE)
                return (result);

        /*
         * Fill in the total length field.
         * XXX: this is a bit tricky.  Since we have already "used" the space
         * for the total length in the buffer, we first remember the entire
         * buffer length in the region, "rewind", and then write the value.
         */
        isc_buffer_usedregion(buffer, &r);
        isc_buffer_clear(buffer);
        isc_buffer_putuint32(buffer, totallen);
        INSIST(isc_buffer_usedlength(buffer) < totallen);

        /*
         * Write the buffer contents to the raw master file.
         */
        result = isc_stdio_write(r.base, 1, (size_t)r.length, f, NULL);

        if (result != ISC_R_SUCCESS) {
                UNEXPECTED_ERROR(__FILE__, __LINE__,
                                 "raw master file write failed: %s",
                                 isc_result_totext(result));
                return (result);
        }

        return (result);
}

static isc_result_t
dump_rdatasets_raw(isc_mem_t *mctx, dns_name_t *name,
                   dns_rdatasetiter_t *rdsiter, dns_totext_ctx_t *ctx,
                   isc_buffer_t *buffer, FILE *f)
{
        isc_result_t result;
        dns_rdataset_t rdataset;

        for (result = dns_rdatasetiter_first(rdsiter);
             result == ISC_R_SUCCESS;
             result = dns_rdatasetiter_next(rdsiter)) {

                dns_rdataset_init(&rdataset);
                dns_rdatasetiter_current(rdsiter, &rdataset);

                if (((rdataset.attributes & DNS_RDATASETATTR_NEGATIVE) != 0) &&
                    (ctx->style.flags & DNS_STYLEFLAG_NCACHE) == 0) {
                        /* Omit negative cache entries */
                } else {
                        result = dump_rdataset_raw(mctx, name, &rdataset,
                                                   buffer, f);
                }
                dns_rdataset_disassociate(&rdataset);
                if (result != ISC_R_SUCCESS)
                        return (result);
        }

        if (result == ISC_R_NOMORE)
                result = ISC_R_SUCCESS;

        return (result);
}

static isc_result_t
dump_rdatasets_map(isc_mem_t *mctx, dns_name_t *name,
                   dns_rdatasetiter_t *rdsiter, dns_totext_ctx_t *ctx,
                   isc_buffer_t *buffer, FILE *f)
{
        UNUSED(mctx);
        UNUSED(name);
        UNUSED(rdsiter);
        UNUSED(ctx);
        UNUSED(buffer);
        UNUSED(f);

        return (ISC_R_NOTIMPLEMENTED);
}

/*
 * Initial size of text conversion buffer.  The buffer is used
 * for several purposes: converting origin names, rdatasets,
 * $DATE timestamps, and comment strings for $TTL directives.
 *
 * When converting rdatasets, it is dynamically resized, but
 * when converting origins, timestamps, etc it is not.  Therefore,
 * the initial size must large enough to hold the longest possible
 * text representation of any domain name (for $ORIGIN).
 */
static const int initial_buffer_length = 1200;

static isc_result_t
dumptostreaminc(dns_dumpctx_t *dctx);

static void
dumpctx_destroy(dns_dumpctx_t *dctx) {

        dctx->magic = 0;
        DESTROYLOCK(&dctx->lock);
        dns_dbiterator_destroy(&dctx->dbiter);
        if (dctx->version != NULL)
                dns_db_closeversion(dctx->db, &dctx->version, ISC_FALSE);
        dns_db_detach(&dctx->db);
        if (dctx->task != NULL)
                isc_task_detach(&dctx->task);
        if (dctx->file != NULL)
                isc_mem_free(dctx->mctx, dctx->file);
        if (dctx->tmpfile != NULL)
                isc_mem_free(dctx->mctx, dctx->tmpfile);
        isc_mem_putanddetach(&dctx->mctx, dctx, sizeof(*dctx));
}

void
dns_dumpctx_attach(dns_dumpctx_t *source, dns_dumpctx_t **target) {

        REQUIRE(DNS_DCTX_VALID(source));
        REQUIRE(target != NULL && *target == NULL);

        LOCK(&source->lock);
        INSIST(source->references > 0);
        source->references++;
        INSIST(source->references != 0);        /* Overflow? */
        UNLOCK(&source->lock);

        *target = source;
}

void
dns_dumpctx_detach(dns_dumpctx_t **dctxp) {
        dns_dumpctx_t *dctx;
        isc_boolean_t need_destroy = ISC_FALSE;

        REQUIRE(dctxp != NULL);
        dctx = *dctxp;
        REQUIRE(DNS_DCTX_VALID(dctx));

        *dctxp = NULL;

        LOCK(&dctx->lock);
        INSIST(dctx->references != 0);
        dctx->references--;
        if (dctx->references == 0)
                need_destroy = ISC_TRUE;
        UNLOCK(&dctx->lock);
        if (need_destroy)
                dumpctx_destroy(dctx);
}

dns_dbversion_t *
dns_dumpctx_version(dns_dumpctx_t *dctx) {
        REQUIRE(DNS_DCTX_VALID(dctx));
        return (dctx->version);
}

dns_db_t *
dns_dumpctx_db(dns_dumpctx_t *dctx) {
        REQUIRE(DNS_DCTX_VALID(dctx));
        return (dctx->db);
}

void
dns_dumpctx_cancel(dns_dumpctx_t *dctx) {
        REQUIRE(DNS_DCTX_VALID(dctx));

        LOCK(&dctx->lock);
        dctx->canceled = ISC_TRUE;
        UNLOCK(&dctx->lock);
}

static isc_result_t
flushandsync(FILE *f, isc_result_t result, const char *temp) {
        isc_boolean_t logit = ISC_TF(result == ISC_R_SUCCESS);

        if (result == ISC_R_SUCCESS)
                result = isc_stdio_flush(f);
        if (result != ISC_R_SUCCESS && logit) {
                if (temp != NULL)
                        isc_log_write(dns_lctx, ISC_LOGCATEGORY_GENERAL,
                                      DNS_LOGMODULE_MASTERDUMP, ISC_LOG_ERROR,
                                      "dumping to master file: %s: flush: %s",
                                      temp, isc_result_totext(result));
                else
                        isc_log_write(dns_lctx, ISC_LOGCATEGORY_GENERAL,
                                      DNS_LOGMODULE_MASTERDUMP, ISC_LOG_ERROR,
                                      "dumping to stream: flush: %s",
                                      isc_result_totext(result));
                logit = ISC_FALSE;
        }

        if (result == ISC_R_SUCCESS)
                result = isc_stdio_sync(f);
        if (result != ISC_R_SUCCESS && logit) {
                if (temp != NULL)
                        isc_log_write(dns_lctx, ISC_LOGCATEGORY_GENERAL,
                                      DNS_LOGMODULE_MASTERDUMP, ISC_LOG_ERROR,
                                      "dumping to master file: %s: fsync: %s",
                                      temp, isc_result_totext(result));
                else
                        isc_log_write(dns_lctx, ISC_LOGCATEGORY_GENERAL,
                                      DNS_LOGMODULE_MASTERDUMP, ISC_LOG_ERROR,
                                      "dumping to stream: fsync: %s",
                                      isc_result_totext(result));
        }
        return (result);
}

static isc_result_t
closeandrename(FILE *f, isc_result_t result, const char *temp, const char *file)
{
        isc_result_t tresult;
        isc_boolean_t logit = ISC_TF(result == ISC_R_SUCCESS);

        result = flushandsync(f, result, temp);
        if (result != ISC_R_SUCCESS)
                logit = ISC_FALSE;

        tresult = isc_stdio_close(f);
        if (result == ISC_R_SUCCESS)
                result = tresult;
        if (result != ISC_R_SUCCESS && logit) {
                isc_log_write(dns_lctx, ISC_LOGCATEGORY_GENERAL,
                              DNS_LOGMODULE_MASTERDUMP, ISC_LOG_ERROR,
                              "dumping master file: %s: fclose: %s",
                              temp, isc_result_totext(result));
                logit = ISC_FALSE;
        }
        if (result == ISC_R_SUCCESS)
                result = isc_file_rename(temp, file);
        else
                (void)isc_file_remove(temp);
        if (result != ISC_R_SUCCESS && logit) {
                isc_log_write(dns_lctx, ISC_LOGCATEGORY_GENERAL,
                              DNS_LOGMODULE_MASTERDUMP, ISC_LOG_ERROR,
                              "dumping master file: rename: %s: %s",
                              file, isc_result_totext(result));
        }
        return (result);
}

static void
dump_quantum(isc_task_t *task, isc_event_t *event) {
        isc_result_t result;
        isc_result_t tresult;
        dns_dumpctx_t *dctx;

        REQUIRE(event != NULL);
        dctx = event->ev_arg;
        REQUIRE(DNS_DCTX_VALID(dctx));
        if (dctx->canceled)
                result = ISC_R_CANCELED;
        else
                result = dumptostreaminc(dctx);
        if (result == DNS_R_CONTINUE) {
                event->ev_arg = dctx;
                isc_task_send(task, &event);
                return;
        }

        if (dctx->file != NULL) {
                tresult = closeandrename(dctx->f, result,
                                         dctx->tmpfile, dctx->file);
                if (tresult != ISC_R_SUCCESS && result == ISC_R_SUCCESS)
                        result = tresult;
        } else
                result = flushandsync(dctx->f, result, NULL);
        (dctx->done)(dctx->done_arg, result);
        isc_event_free(&event);
        dns_dumpctx_detach(&dctx);
}

static isc_result_t
task_send(dns_dumpctx_t *dctx) {
        isc_event_t *event;

        event = isc_event_allocate(dctx->mctx, NULL, DNS_EVENT_DUMPQUANTUM,
                                   dump_quantum, dctx, sizeof(*event));
        if (event == NULL)
                return (ISC_R_NOMEMORY);
        isc_task_send(dctx->task, &event);
        return (ISC_R_SUCCESS);
}

static isc_result_t
dumpctx_create(isc_mem_t *mctx, dns_db_t *db, dns_dbversion_t *version,
               const dns_master_style_t *style, FILE *f, dns_dumpctx_t **dctxp,
               dns_masterformat_t format, dns_masterrawheader_t *header)
{
        dns_dumpctx_t *dctx;
        isc_result_t result;
        unsigned int options;

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

        dctx->mctx = NULL;
        dctx->f = f;
        dctx->dbiter = NULL;
        dctx->db = NULL;
        dctx->version = NULL;
        dctx->done = NULL;
        dctx->done_arg = NULL;
        dctx->task = NULL;
        dctx->nodes = 0;
        dctx->first = ISC_TRUE;
        dctx->canceled = ISC_FALSE;
        dctx->file = NULL;
        dctx->tmpfile = NULL;
        dctx->format = format;
        if (header == NULL)
                dns_master_initrawheader(&dctx->header);
        else
                dctx->header = *header;

        switch (format) {
        case dns_masterformat_text:
                dctx->dumpsets = dump_rdatasets_text;
                break;
        case dns_masterformat_raw:
                dctx->dumpsets = dump_rdatasets_raw;
                break;
        case dns_masterformat_map:
                dctx->dumpsets = dump_rdatasets_map;
                break;
        default:
                INSIST(0);
                break;
        }

        result = totext_ctx_init(style, &dctx->tctx);
        if (result != ISC_R_SUCCESS) {
                UNEXPECTED_ERROR(__FILE__, __LINE__,
                                 "could not set master file style");
                goto cleanup;
        }

        isc_stdtime_get(&dctx->now);
        dns_db_attach(db, &dctx->db);

        dctx->do_date = dns_db_iscache(dctx->db);

        if (dctx->format == dns_masterformat_text &&
            (dctx->tctx.style.flags & DNS_STYLEFLAG_REL_OWNER) != 0) {
                options = DNS_DB_RELATIVENAMES;
        } else
                options = 0;
        result = dns_db_createiterator(dctx->db, options, &dctx->dbiter);
        if (result != ISC_R_SUCCESS)
                goto cleanup;

        result = isc_mutex_init(&dctx->lock);
        if (result != ISC_R_SUCCESS)
                goto cleanup;
        if (version != NULL)
                dns_db_attachversion(dctx->db, version, &dctx->version);
        else if (!dns_db_iscache(db))
                dns_db_currentversion(dctx->db, &dctx->version);
        isc_mem_attach(mctx, &dctx->mctx);
        dctx->references = 1;
        dctx->magic = DNS_DCTX_MAGIC;
        *dctxp = dctx;
        return (ISC_R_SUCCESS);

 cleanup:
        if (dctx->dbiter != NULL)
                dns_dbiterator_destroy(&dctx->dbiter);
        if (dctx->db != NULL)
                dns_db_detach(&dctx->db);
        if (dctx != NULL)
                isc_mem_put(mctx, dctx, sizeof(*dctx));
        return (result);
}

static isc_result_t
writeheader(dns_dumpctx_t *dctx) {
        isc_result_t result = ISC_R_SUCCESS;
        isc_buffer_t buffer;
        char *bufmem;
        isc_region_t r;
        dns_masterrawheader_t rawheader;
        isc_uint32_t rawversion, now32;

        bufmem = isc_mem_get(dctx->mctx, initial_buffer_length);
        if (bufmem == NULL)
                return (ISC_R_NOMEMORY);

        isc_buffer_init(&buffer, bufmem, initial_buffer_length);

        switch (dctx->format) {
        case dns_masterformat_text:
                /*
                 * If the database has cache semantics, output an
                 * RFC2540 $DATE directive so that the TTLs can be
                 * adjusted when it is reloaded.  For zones it is not
                 * really needed, and it would make the file
                 * incompatible with pre-RFC2540 software, so we omit
                 * it in the zone case.
                 */
                if (dctx->do_date) {
                        result = dns_time32_totext(dctx->now, &buffer);
                        RUNTIME_CHECK(result == ISC_R_SUCCESS);
                        isc_buffer_usedregion(&buffer, &r);
                        fprintf(dctx->f, "$DATE %.*s\n",
                                (int) r.length, (char *) r.base);
                }
                break;
        case dns_masterformat_raw:
        case dns_masterformat_map:
                r.base = (unsigned char *)&rawheader;
                r.length = sizeof(rawheader);
                isc_buffer_region(&buffer, &r);
#if !defined(STDTIME_ON_32BITS) || (STDTIME_ON_32BITS + 0) != 1
                /*
                 * We assume isc_stdtime_t is a 32-bit integer,
                 * which should be the case on most platforms.
                 * If it turns out to be uncommon, we'll need
                 * to bump the version number and revise the
                 * header format.
                 */
                isc_log_write(dns_lctx,
                              ISC_LOGCATEGORY_GENERAL,
                              DNS_LOGMODULE_MASTERDUMP,
                              ISC_LOG_INFO,
                              "dumping master file in raw "
                              "format: stdtime is not 32bits");
                now32 = 0;
#else
                now32 = dctx->now;
#endif
                rawversion = 1;
                if ((dctx->header.flags & DNS_MASTERRAW_COMPAT) != 0)
                        rawversion = 0;

                isc_buffer_putuint32(&buffer, dctx->format);
                isc_buffer_putuint32(&buffer, rawversion);
                isc_buffer_putuint32(&buffer, now32);

                if (rawversion == 1) {
                        isc_buffer_putuint32(&buffer, dctx->header.flags);
                        isc_buffer_putuint32(&buffer,
                                             dctx->header.sourceserial);
                        isc_buffer_putuint32(&buffer, dctx->header.lastxfrin);
                }

                INSIST(isc_buffer_usedlength(&buffer) <= sizeof(rawheader));
                result = isc_stdio_write(buffer.base, 1,
                                         isc_buffer_usedlength(&buffer),
                                         dctx->f, NULL);
                if (result != ISC_R_SUCCESS)
                        break;

                break;
        default:
                INSIST(0);
        }

        isc_mem_put(dctx->mctx, buffer.base, buffer.length);
        return (result);
}

static isc_result_t
dumptostreaminc(dns_dumpctx_t *dctx) {
        isc_result_t result = ISC_R_SUCCESS;
        isc_buffer_t buffer;
        char *bufmem;
        dns_name_t *name;
        dns_fixedname_t fixname;
        unsigned int nodes;
        isc_time_t start;

        bufmem = isc_mem_get(dctx->mctx, initial_buffer_length);
        if (bufmem == NULL)
                return (ISC_R_NOMEMORY);

        isc_buffer_init(&buffer, bufmem, initial_buffer_length);

        dns_fixedname_init(&fixname);
        name = dns_fixedname_name(&fixname);

        if (dctx->first) {
                CHECK(writeheader(dctx));

                /*
                 * Fast format is not currently written incrementally,
                 * so we make the call to dns_db_serialize() here.
                 * If the database is anything other than an rbtdb,
                 * this should result in not implemented
                 */
                if (dctx->format == dns_masterformat_map) {
                        result = dns_db_serialize(dctx->db, dctx->version,
                                                  dctx->f);
                        goto cleanup;
                }

                result = dns_dbiterator_first(dctx->dbiter);
                if (result != ISC_R_SUCCESS && result != ISC_R_NOMORE)
                        goto cleanup;

                dctx->first = ISC_FALSE;
        } else
                result = ISC_R_SUCCESS;

        nodes = dctx->nodes;
        isc_time_now(&start);
        while (result == ISC_R_SUCCESS && (dctx->nodes == 0 || nodes--)) {
                dns_rdatasetiter_t *rdsiter = NULL;
                dns_dbnode_t *node = NULL;

                result = dns_dbiterator_current(dctx->dbiter, &node, name);
                if (result != ISC_R_SUCCESS && result != DNS_R_NEWORIGIN)
                        break;
                if (result == DNS_R_NEWORIGIN) {
                        dns_name_t *origin =
                                dns_fixedname_name(&dctx->tctx.origin_fixname);
                        result = dns_dbiterator_origin(dctx->dbiter, origin);
                        RUNTIME_CHECK(result == ISC_R_SUCCESS);
                        if ((dctx->tctx.style.flags &
                             DNS_STYLEFLAG_REL_DATA) != 0)
                                dctx->tctx.origin = origin;
                        dctx->tctx.neworigin = origin;
                }
                result = dns_db_allrdatasets(dctx->db, node, dctx->version,
                                             dctx->now, &rdsiter);
                if (result != ISC_R_SUCCESS) {
                        dns_db_detachnode(dctx->db, &node);
                        goto cleanup;
                }
                result = (dctx->dumpsets)(dctx->mctx, name, rdsiter,
                                          &dctx->tctx, &buffer, dctx->f);
                dns_rdatasetiter_destroy(&rdsiter);
                if (result != ISC_R_SUCCESS) {
                        dns_db_detachnode(dctx->db, &node);
                        goto cleanup;
                }
                dns_db_detachnode(dctx->db, &node);
                result = dns_dbiterator_next(dctx->dbiter);
        }

        /*
         * Work out how many nodes can be written in the time between
         * two requests to the nameserver.  Smooth the resulting number and
         * use it as a estimate for the number of nodes to be written in the
         * next iteration.
         */
        if (dctx->nodes != 0 && result == ISC_R_SUCCESS) {
                unsigned int pps = dns_pps;     /* packets per second */
                unsigned int interval;
                isc_uint64_t usecs;
                isc_time_t end;

                isc_time_now(&end);
                if (pps < 100)
                        pps = 100;
                interval = 1000000 / pps;       /* interval in usecs */
                if (interval == 0)
                        interval = 1;
                usecs = isc_time_microdiff(&end, &start);
                if (usecs == 0) {
                        dctx->nodes = dctx->nodes * 2;
                        if (dctx->nodes > 1000)
                                dctx->nodes = 1000;
                } else {
                        nodes = dctx->nodes * interval;
                        nodes /= (unsigned int)usecs;
                        if (nodes == 0)
                                nodes = 1;
                        else if (nodes > 1000)
                                nodes = 1000;

                        /* Smooth and assign. */
                        dctx->nodes = (nodes + dctx->nodes * 7) / 8;

                        isc_log_write(dns_lctx, ISC_LOGCATEGORY_GENERAL,
                                      DNS_LOGMODULE_MASTERDUMP,
                                      ISC_LOG_DEBUG(1),
                                      "dumptostreaminc(%p) new nodes -> %d\n",
                                      dctx, dctx->nodes);
                }
                result = DNS_R_CONTINUE;
        } else if (result == ISC_R_NOMORE)
                result = ISC_R_SUCCESS;
 cleanup:
        RUNTIME_CHECK(dns_dbiterator_pause(dctx->dbiter) == ISC_R_SUCCESS);
        isc_mem_put(dctx->mctx, buffer.base, buffer.length);
        return (result);
}

isc_result_t
dns_master_dumptostreaminc(isc_mem_t *mctx, dns_db_t *db,
                           dns_dbversion_t *version,
                           const dns_master_style_t *style,
                           FILE *f, isc_task_t *task,
                           dns_dumpdonefunc_t done, void *done_arg,
                           dns_dumpctx_t **dctxp)
{
        dns_dumpctx_t *dctx = NULL;
        isc_result_t result;

        REQUIRE(task != NULL);
        REQUIRE(f != NULL);
        REQUIRE(done != NULL);

        result = dumpctx_create(mctx, db, version, style, f, &dctx,
                                dns_masterformat_text, NULL);
        if (result != ISC_R_SUCCESS)
                return (result);
        isc_task_attach(task, &dctx->task);
        dctx->done = done;
        dctx->done_arg = done_arg;
        dctx->nodes = 100;

        result = task_send(dctx);
        if (result == ISC_R_SUCCESS) {
                dns_dumpctx_attach(dctx, dctxp);
                return (DNS_R_CONTINUE);
        }

        dns_dumpctx_detach(&dctx);
        return (result);
}

/*
 * Dump an entire database into a master file.
 */
isc_result_t
dns_master_dumptostream(isc_mem_t *mctx, dns_db_t *db,
                        dns_dbversion_t *version,
                        const dns_master_style_t *style,
                        FILE *f)
{
        return (dns_master_dumptostream3(mctx, db, version, style,
                                         dns_masterformat_text, NULL, f));
}

isc_result_t
dns_master_dumptostream2(isc_mem_t *mctx, dns_db_t *db,
                         dns_dbversion_t *version,
                         const dns_master_style_t *style,
                         dns_masterformat_t format, FILE *f)
{
        return (dns_master_dumptostream3(mctx, db, version, style,
                                         format, NULL, f));
}

isc_result_t
dns_master_dumptostream3(isc_mem_t *mctx, dns_db_t *db,
                         dns_dbversion_t *version,
                         const dns_master_style_t *style,
                         dns_masterformat_t format,
                         dns_masterrawheader_t *header, FILE *f)
{
        dns_dumpctx_t *dctx = NULL;
        isc_result_t result;

        result = dumpctx_create(mctx, db, version, style, f, &dctx,
                                format, header);
        if (result != ISC_R_SUCCESS)
                return (result);

        result = dumptostreaminc(dctx);
        INSIST(result != DNS_R_CONTINUE);
        dns_dumpctx_detach(&dctx);

        result = flushandsync(f, result, NULL);
        return (result);
}

static isc_result_t
opentmp(isc_mem_t *mctx, dns_masterformat_t format, const char *file,
        char **tempp, FILE **fp) {
        FILE *f = NULL;
        isc_result_t result;
        char *tempname = NULL;
        int tempnamelen;

        tempnamelen = strlen(file) + 20;
        tempname = isc_mem_allocate(mctx, tempnamelen);
        if (tempname == NULL)
                return (ISC_R_NOMEMORY);

        result = isc_file_mktemplate(file, tempname, tempnamelen);
        if (result != ISC_R_SUCCESS)
                goto cleanup;

        if (format == dns_masterformat_text)
                result = isc_file_openunique(tempname, &f);
        else
                result = isc_file_bopenunique(tempname, &f);
        if (result != ISC_R_SUCCESS) {
                isc_log_write(dns_lctx, ISC_LOGCATEGORY_GENERAL,
                              DNS_LOGMODULE_MASTERDUMP, ISC_LOG_ERROR,
                              "dumping master file: %s: open: %s",
                              tempname, isc_result_totext(result));
                goto cleanup;
        }
        *tempp = tempname;
        *fp = f;
        return (ISC_R_SUCCESS);

cleanup:
        isc_mem_free(mctx, tempname);
        return (result);
}

isc_result_t
dns_master_dumpinc(isc_mem_t *mctx, dns_db_t *db, dns_dbversion_t *version,
                   const dns_master_style_t *style, const char *filename,
                   isc_task_t *task, dns_dumpdonefunc_t done, void *done_arg,
                   dns_dumpctx_t **dctxp)
{
        return (dns_master_dumpinc3(mctx, db, version, style, filename, task,
                                    done, done_arg, dctxp,
                                    dns_masterformat_text, NULL));
}

isc_result_t
dns_master_dumpinc2(isc_mem_t *mctx, dns_db_t *db, dns_dbversion_t *version,
                    const dns_master_style_t *style, const char *filename,
                    isc_task_t *task, dns_dumpdonefunc_t done, void *done_arg,
                    dns_dumpctx_t **dctxp, dns_masterformat_t format)
{
        return (dns_master_dumpinc3(mctx, db, version, style, filename, task,
                                    done, done_arg, dctxp, format, NULL));
}

isc_result_t
dns_master_dumpinc3(isc_mem_t *mctx, dns_db_t *db, dns_dbversion_t *version,
                    const dns_master_style_t *style, const char *filename,
                    isc_task_t *task, dns_dumpdonefunc_t done, void *done_arg,
                    dns_dumpctx_t **dctxp, dns_masterformat_t format,
                    dns_masterrawheader_t *header)
{
        FILE *f = NULL;
        isc_result_t result;
        char *tempname = NULL;
        char *file = NULL;
        dns_dumpctx_t *dctx = NULL;

        file = isc_mem_strdup(mctx, filename);
        if (file == NULL)
                return (ISC_R_NOMEMORY);

        result = opentmp(mctx, format, filename, &tempname, &f);
        if (result != ISC_R_SUCCESS)
                goto cleanup;

        result = dumpctx_create(mctx, db, version, style, f, &dctx,
                                format, header);
        if (result != ISC_R_SUCCESS) {
                (void)isc_stdio_close(f);
                (void)isc_file_remove(tempname);
                goto cleanup;
        }

        isc_task_attach(task, &dctx->task);
        dctx->done = done;
        dctx->done_arg = done_arg;
        dctx->nodes = 100;
        dctx->file = file;
        file = NULL;
        dctx->tmpfile = tempname;
        tempname = NULL;

        result = task_send(dctx);
        if (result == ISC_R_SUCCESS) {
                dns_dumpctx_attach(dctx, dctxp);
                return (DNS_R_CONTINUE);
        }

 cleanup:
        if (dctx != NULL)
                dns_dumpctx_detach(&dctx);
        if (file != NULL)
                isc_mem_free(mctx, file);
        if (tempname != NULL)
                isc_mem_free(mctx, tempname);
        return (result);
}

isc_result_t
dns_master_dump(isc_mem_t *mctx, dns_db_t *db, dns_dbversion_t *version,
                const dns_master_style_t *style, const char *filename)
{
        return (dns_master_dump3(mctx, db, version, style, filename,
                                 dns_masterformat_text, NULL));
}

isc_result_t
dns_master_dump2(isc_mem_t *mctx, dns_db_t *db, dns_dbversion_t *version,
                 const dns_master_style_t *style, const char *filename,
                 dns_masterformat_t format)
{
        return (dns_master_dump3(mctx, db, version, style, filename,
                                 format, NULL));
}

isc_result_t
dns_master_dump3(isc_mem_t *mctx, dns_db_t *db, dns_dbversion_t *version,
                 const dns_master_style_t *style, const char *filename,
                 dns_masterformat_t format, dns_masterrawheader_t *header)
{
        FILE *f = NULL;
        isc_result_t result;
        char *tempname;
        dns_dumpctx_t *dctx = NULL;

        result = opentmp(mctx, format, filename, &tempname, &f);
        if (result != ISC_R_SUCCESS)
                return (result);

        result = dumpctx_create(mctx, db, version, style, f, &dctx,
                                format, header);
        if (result != ISC_R_SUCCESS)
                goto cleanup;

        result = dumptostreaminc(dctx);
        INSIST(result != DNS_R_CONTINUE);
        dns_dumpctx_detach(&dctx);

        result = closeandrename(f, result, tempname, filename);

 cleanup:
        isc_mem_free(mctx, tempname);
        return (result);
}

/*
 * Dump a database node into a master file.
 * XXX: this function assumes the text format.
 */
isc_result_t
dns_master_dumpnodetostream(isc_mem_t *mctx, dns_db_t *db,
                            dns_dbversion_t *version,
                            dns_dbnode_t *node, dns_name_t *name,
                            const dns_master_style_t *style,
                            FILE *f)
{
        isc_result_t result;
        isc_buffer_t buffer;
        char *bufmem;
        isc_stdtime_t now;
        dns_totext_ctx_t ctx;
        dns_rdatasetiter_t *rdsiter = NULL;

        result = totext_ctx_init(style, &ctx);
        if (result != ISC_R_SUCCESS) {
                UNEXPECTED_ERROR(__FILE__, __LINE__,
                                 "could not set master file style");
                return (ISC_R_UNEXPECTED);
        }

        isc_stdtime_get(&now);

        bufmem = isc_mem_get(mctx, initial_buffer_length);
        if (bufmem == NULL)
                return (ISC_R_NOMEMORY);

        isc_buffer_init(&buffer, bufmem, initial_buffer_length);

        result = dns_db_allrdatasets(db, node, version, now, &rdsiter);
        if (result != ISC_R_SUCCESS)
                goto failure;
        result = dump_rdatasets_text(mctx, name, rdsiter, &ctx, &buffer, f);
        if (result != ISC_R_SUCCESS)
                goto failure;
        dns_rdatasetiter_destroy(&rdsiter);

        result = ISC_R_SUCCESS;

 failure:
        isc_mem_put(mctx, buffer.base, buffer.length);
        return (result);
}

isc_result_t
dns_master_dumpnode(isc_mem_t *mctx, dns_db_t *db, dns_dbversion_t *version,
                    dns_dbnode_t *node, dns_name_t *name,
                    const dns_master_style_t *style, const char *filename)
{
        FILE *f = NULL;
        isc_result_t result;

        result = isc_stdio_open(filename, "w", &f);
        if (result != ISC_R_SUCCESS) {
                isc_log_write(dns_lctx, ISC_LOGCATEGORY_GENERAL,
                              DNS_LOGMODULE_MASTERDUMP, ISC_LOG_ERROR,
                              "dumping node to file: %s: open: %s", filename,
                              isc_result_totext(result));
                return (ISC_R_UNEXPECTED);
        }

        result = dns_master_dumpnodetostream(mctx, db, version, node, name,
                                             style, f);
        if (result != ISC_R_SUCCESS) {
                isc_log_write(dns_lctx, ISC_LOGCATEGORY_GENERAL,
                              DNS_LOGMODULE_MASTERDUMP, ISC_LOG_ERROR,
                              "dumping master file: %s: dump: %s", filename,
                              isc_result_totext(result));
                (void)isc_stdio_close(f);
                return (ISC_R_UNEXPECTED);
        }

        result = isc_stdio_close(f);
        if (result != ISC_R_SUCCESS) {
                isc_log_write(dns_lctx, ISC_LOGCATEGORY_GENERAL,
                              DNS_LOGMODULE_MASTERDUMP, ISC_LOG_ERROR,
                              "dumping master file: %s: close: %s", filename,
                              isc_result_totext(result));
                return (ISC_R_UNEXPECTED);
        }

        return (result);
}

isc_result_t
dns_master_stylecreate(dns_master_style_t **stylep, unsigned int flags,
                       unsigned int ttl_column, unsigned int class_column,
                       unsigned int type_column, unsigned int rdata_column,
                       unsigned int line_length, unsigned int tab_width,
                       isc_mem_t *mctx)
{
        return (dns_master_stylecreate2(stylep, flags, ttl_column,
                                        class_column, type_column,
                                        rdata_column, line_length,
                                        tab_width, 0xffffffff, mctx));
}

isc_result_t
dns_master_stylecreate2(dns_master_style_t **stylep, unsigned int flags,
                        unsigned int ttl_column, unsigned int class_column,
                        unsigned int type_column, unsigned int rdata_column,
                        unsigned int line_length, unsigned int tab_width,
                        unsigned int split_width, isc_mem_t *mctx)
{
        dns_master_style_t *style;

        REQUIRE(stylep != NULL && *stylep == NULL);
        style = isc_mem_get(mctx, sizeof(*style));
        if (style == NULL)
                return (ISC_R_NOMEMORY);

        style->flags = flags;
        style->ttl_column = ttl_column;
        style->class_column = class_column;
        style->type_column = type_column;
        style->rdata_column = rdata_column;
        style->line_length = line_length;
        style->tab_width = tab_width;
        style->split_width = split_width;

        *stylep = style;
        return (ISC_R_SUCCESS);
}

void
dns_master_styledestroy(dns_master_style_t **stylep, isc_mem_t *mctx) {
        dns_master_style_t *style;

        REQUIRE(stylep != NULL && *stylep != NULL);
        style = *stylep;
        *stylep = NULL;
        isc_mem_put(mctx, style, sizeof(*style));
}

---