/src/bind9/lib/dns/masterdump.c

Source
/*
 * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
 *
 * SPDX-License-Identifier: MPL-2.0
 *
 * 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 https://mozilla.org/MPL/2.0/.
 *
 * See the COPYRIGHT file distributed with this work for additional
 * information regarding copyright ownership.
 */

/*! \file */

#include <inttypes.h>
#include <stdbool.h>
#include <stdlib.h>

#include <isc/async.h>
#include <isc/atomic.h>
#include <isc/buffer.h>
#include <isc/file.h>
#include <isc/log.h>
#include <isc/loop.h>
#include <isc/magic.h>
#include <isc/mem.h>
#include <isc/refcount.h>
#include <isc/result.h>
#include <isc/stdio.h>
#include <isc/string.h>
#include <isc/time.h>
#include <isc/types.h>
#include <isc/util.h>
#include <isc/work.h>

#include <dns/db.h>
#include <dns/dbiterator.h>
#include <dns/fixedname.h>
#include <dns/master.h>
#include <dns/masterdump.h>
#include <dns/ncache.h>
#include <dns/rdata.h>
#include <dns/rdataclass.h>
#include <dns/rdatasetiter.h>
#include <dns/rdatatype.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)

struct dns_master_style {
  dns_masterstyle_flags_t 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

/*% Does the rdataset 'r' contain a stale answer? */
#define STALE(r) (((r)->attributes.stale))
/*% Does the rdataset 'r' contain an expired answer? */
#define ANCIENT(r) (((r)->attributes.ancient))

/*%
 * Context structure for a masterfile dump in progress.
 */
typedef struct dns_totext_ctx {
  dns_master_style_t style;
  bool class_printed;
  char *linebreak;
  char linebreak_buf[DNS_TOTEXT_LINEBREAK_MAXLEN];
  dns_name_t *origin;
  dns_name_t *neworigin;
  dns_fixedname_t origin_fixname;
  uint32_t current_ttl;
  bool current_ttl_valid;
  dns_ttl_t serve_stale_ttl;
  dns_indent_t indent;
} dns_totext_ctx_t;

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
};

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
};

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

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

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
};

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

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().
 */
const dns_master_style_t dns_master_style_debug = {
  DNS_STYLEFLAG_REL_OWNER, 24, 32, 40, 48, 80, 8, UINT_MAX
};

/*%
 * Similar, but indented (i.e., prepended with indentctx.string).
 */
const dns_master_style_t dns_master_style_indent = {
  DNS_STYLEFLAG_REL_OWNER | DNS_STYLEFLAG_INDENT,
  24,
  32,
  40,
  48,
  80,
  8,
  UINT_MAX
};

/*%
 * Similar, but with each line commented out.
 */
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
};

/*%
 * YAML style
 */
const dns_master_style_t dns_master_style_yaml = {
  DNS_STYLEFLAG_YAML | DNS_STYLEFLAG_REL_OWNER | DNS_STYLEFLAG_INDENT,
  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;
  isc_refcount_t references;
  atomic_bool canceled;
  isc_stdtime_t now;
  FILE *f;
  dns_db_t *db;
  dns_dbversion_t *version;
  dns_dbiterator_t *dbiter;
  dns_totext_ctx_t tctx;
  dns_dumpdonefunc_t done;
  void *done_arg;
  /* dns_master_dumpasync() */
  isc_result_t result;
  char *file;
  char *tmpfile;
  dns_masterformat_t format;
  dns_masterrawheader_t header;
  isc_result_t (*dumpsets)(isc_mem_t *mctx, const dns_name_t *name,
         dns_rdatasetiter_t *rdsiter,
         dns_totext_ctx_t *ctx, isc_buffer_t *buffer,
         FILE *f);
};

#define NXDOMAIN(x) (((x)->attributes.nxdomain))

static const dns_indent_t default_indent = { "\t", 1 };
static const dns_indent_t default_yamlindent = { "  ", 1 };

/*%
 * 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 int)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 int)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, const dns_indent_t *indentctx,
    dns_totext_ctx_t *ctx) {
  isc_result_t result;

  REQUIRE(style->tab_width != 0);

  if (indentctx == NULL) {
    if ((style->flags & DNS_STYLEFLAG_YAML) != 0) {
      indentctx = &default_yamlindent;
    } else {
      indentctx = &default_indent;
    }
  }

  ctx->style = *style;
  ctx->class_printed = 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_INDENT) != 0 ||
        (ctx->style.flags & DNS_STYLEFLAG_YAML) != 0)
    {
      unsigned int i, len = strlen(indentctx->string);
      for (i = 0; i < indentctx->count; i++) {
        if (isc_buffer_availablelength(&buf) < len) {
          return DNS_R_TEXTTOOLONG;
        }
        isc_buffer_putstr(&buf, indentctx->string);
      }
    }

    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 = false;
  ctx->serve_stale_ttl = 0;
  ctx->indent = *indentctx;

  return ISC_R_SUCCESS;
}

#define INDENT_TO(col)                                                        \
  do {                                                                  \
    if ((ctx->style.flags & DNS_STYLEFLAG_YAML) != 0) {           \
      if ((result = str_totext(" ", target)) !=             \
          ISC_R_SUCCESS)                                    \
        return ((result));                            \
    } else 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
yaml_stringify(isc_buffer_t *target, char *start) {
  isc_region_t r;
  char *s = start;
  char *tmp = NULL;

  isc_buffer_availableregion(target, &r);
  if (r.length < 1) {
    return ISC_R_NOSPACE;
  }

  /* NUL terminate buffer for string operations below */
  r.base[0] = '\0';

  /* Escape quotes in string using quote quote */
  while ((tmp = strchr(s, '\'')) != NULL) {
    isc_buffer_availableregion(target, &r);
    /* Space to shift by 1 with trailing NUL? */
    if (r.length < 2) {
      return ISC_R_NOSPACE;
    }
    memmove(tmp + 1, tmp,
      (char *)isc_buffer_used(target) - tmp + 1);
    isc_buffer_add(target, 1);
    /* We now have "''..." - skip both quotes. */
    s = tmp + 2;
  }

  return ISC_R_SUCCESS;
}

static isc_result_t
ncache_summary(dns_rdataset_t *rdataset, bool omit_final_dot,
         dns_totext_ctx_t *ctx, isc_buffer_t *target) {
  isc_result_t result = ISC_R_SUCCESS;
  dns_rdataset_t rds = DNS_RDATASET_INIT;
  dns_name_t name;
  char *start = NULL;

  dns_name_init(&name);

  do {
    dns_ncache_current(rdataset, &name, &rds);
    DNS_RDATASET_FOREACH(&rds) {
      if ((ctx->style.flags & DNS_STYLEFLAG_INDENT) != 0 ||
          (ctx->style.flags & DNS_STYLEFLAG_YAML) != 0)
      {
        unsigned int i;
        for (i = 0; i < ctx->indent.count; i++) {
          CHECK(str_totext(ctx->indent.string,
               target));
        }
      }

      if ((ctx->style.flags & DNS_STYLEFLAG_YAML) != 0) {
        CHECK(str_totext("- '", target));
        start = isc_buffer_used(target);
      } else {
        CHECK(str_totext("; ", target));
      }

      CHECK(dns_name_totext(
        &name,
        omit_final_dot ? DNS_NAME_OMITFINALDOT : 0,
        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(" ...", 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));
      }
      if (start != NULL) {
        RETERR(yaml_stringify(target, start));
        CHECK(str_totext("\'", 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:
  dns_rdataset_cleanup(&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, const dns_name_t *owner_name,
    dns_totext_ctx_t *ctx, bool omit_final_dot,
    isc_buffer_t *target) {
  isc_result_t result;
  unsigned int column;
  bool first = true;
  uint32_t current_ttl;
  bool current_ttl_valid;
  dns_rdatatype_t type;
  unsigned int type_start;
  dns_fixedname_t fixed;
  dns_name_t *name = NULL;
  unsigned int i;
  char *start = NULL;

  REQUIRE(DNS_RDATASET_VALID(rdataset));

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

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

  DNS_RDATASET_FOREACH(rdataset) {
    column = 0;

    /*
     * Indent?
     */
    if ((ctx->style.flags & DNS_STYLEFLAG_INDENT) != 0 ||
        (ctx->style.flags & DNS_STYLEFLAG_YAML) != 0)
    {
      for (i = 0; i < ctx->indent.count; i++) {
        RETERR(str_totext(ctx->indent.string, target));
      }
    }

    /*
     * YAML or comment prefix?
     */
    if ((ctx->style.flags & DNS_STYLEFLAG_YAML) != 0) {
      RETERR(str_totext("- '", target));
      start = isc_buffer_used(target);
    } else 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 ? DNS_NAME_OMITFINALDOT : 0,
        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;
        RETERR(dns_ttl_totext(rdataset->ttl, false,
                  false, target));
        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 = true;
      }
    }

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

    /*
     * Type.
     */

    if (rdataset->attributes.negative) {
      type = rdataset->covers;
    } else {
      type = rdataset->type;
    }

    INDENT_TO(type_column);
    type_start = target->used;
    if (rdataset->attributes.negative) {
      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:
      if ((ctx->style.flags & DNS_STYLEFLAG_UNKNOWNFORMAT) !=
          0)
      {
        result = dns_rdatatype_tounknowntext(type,
                     target);
      } else {
        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.negative) {
      if (NXDOMAIN(rdataset)) {
        RETERR(str_totext(";-$NXDOMAIN", target));
      } else {
        RETERR(str_totext(";-$NXRRSET", target));
      }
      if (start != NULL) {
        RETERR(yaml_stringify(target, start));
        RETERR(str_totext("'\n", target));
      } else {
        RETERR(str_totext("\n", target));
      }

      /*
       * Print a summary of the cached records which make
       * up the negative response.
       */
      RETERR(ncache_summary(rdataset, omit_final_dot, ctx,
                target));
      break;
    } else {
      dns_rdata_t rdata = DNS_RDATA_INIT;

      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));
      if (start != NULL) {
        RETERR(yaml_stringify(target, start));
        RETERR(str_totext("'\n", target));
      } else {
        RETERR(str_totext("\n", target));
      }
    }

    first = false;
  }

  /*
   * 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 = 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, const dns_name_t *owner_name,
    dns_totext_ctx_t *ctx, bool omit_final_dot,
    isc_buffer_t *target) {
  unsigned int column;
  isc_result_t result;
  char *start = NULL;

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

  column = 0;

  if ((ctx->style.flags & DNS_STYLEFLAG_YAML) != 0) {
    RETERR(str_totext("- '", target));
    start = isc_buffer_used(target);
  }

  /* Owner name */
  {
    unsigned int name_start = target->used;
    unsigned int opts = omit_final_dot ? DNS_NAME_OMITFINALDOT : 0;
    RETERR(dns_name_totext(owner_name, opts, target));
    column += target->used - name_start;
  }

  /* Class */
  {
    unsigned int class_start;
    INDENT_TO(class_column);
    class_start = target->used;
    if ((ctx->style.flags & DNS_STYLEFLAG_UNKNOWNFORMAT) != 0) {
      result = dns_rdataclass_tounknowntext(rdataset->rdclass,
                    target);
    } else {
      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;
    if ((ctx->style.flags & DNS_STYLEFLAG_UNKNOWNFORMAT) != 0) {
      result = dns_rdatatype_tounknowntext(rdataset->type,
                   target);
    } else {
      result = dns_rdatatype_totext(rdataset->type, target);
    }
    if (result != ISC_R_SUCCESS) {
      return result;
    }
    column += (target->used - type_start);
  }

  if (start != NULL) {
    RETERR(yaml_stringify(target, start));
    RETERR(str_totext("\'", target));
  }
  RETERR(str_totext("\n", target));

  return ISC_R_SUCCESS;
}

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

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

isc_result_t
dns_master_questiontotext(const 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, NULL, &ctx);
  if (result != ISC_R_SUCCESS) {
    UNEXPECTED_ERROR("could not set master file style");
    return ISC_R_UNEXPECTED;
  }

  return question_totext(rdataset, owner_name, &ctx, 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, const 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 ||
        ctx->current_ttl != rdataset->ttl)
    {
      if ((ctx->style.flags & DNS_STYLEFLAG_COMMENT) != 0) {
        isc_buffer_clear(buffer);
        result = dns_ttl_totext(rdataset->ttl, true,
              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 = 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, false, buffer);
    if (result != ISC_R_NOSPACE) {
      break;
    }

    newlength = buffer->length * 2;
    newmem = isc_mem_get(mctx, newlength);
    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("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, const 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, 0, 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;
  }

  if ((ctx->style.flags & DNS_STYLEFLAG_CLASS_PERNAME) != 0) {
    ctx->class_printed = false;
  }

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;

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

  for (i = 0; i < n; i++) {
    dns_rdataset_t *rds = sorted[i];

    if (ANCIENT(rds) &&
        (ctx->style.flags & DNS_STYLEFLAG_EXPIRED) == 0)
    {
      /* Omit expired entries */
      dns_rdataset_disassociate(rds);
      continue;
    }

    if ((ctx->style.flags & DNS_STYLEFLAG_TRUST) != 0) {
      if ((ctx->style.flags & DNS_STYLEFLAG_INDENT) != 0 ||
          (ctx->style.flags & DNS_STYLEFLAG_YAML) != 0)
      {
        unsigned int j;
        for (j = 0; j < ctx->indent.count; j++) {
          fprintf(f, "%s", ctx->indent.string);
        }
      }
      fprintf(f, "; %s\n", dns_trust_totext(rds->trust));
    }
    if ((rds->attributes.negative) &&
        (ctx->style.flags & DNS_STYLEFLAG_NCACHE) == 0)
    {
      /* Omit negative cache entries */
    } else {
      isc_result_t result;
      if (STALE(rds)) {
        isc_buffer_t b;
        char buf[sizeof("YYYYMMDDHHMMSS")];
        memset(buf, 0, sizeof(buf));
        isc_buffer_init(&b, buf, sizeof(buf) - 1);
        dns_time64_totext((uint64_t)rds->expire, &b);
        fprintf(f, "; stale since %s\n", buf);
      } else if (ANCIENT(rds)) {
        fprintf(f, "; expired (awaiting cleanup)\n");
      }
      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) != 0) &&
        (rds->attributes.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((uint64_t)rds->resign, &b);
      if ((ctx->style.flags & DNS_STYLEFLAG_INDENT) != 0 ||
          (ctx->style.flags & DNS_STYLEFLAG_YAML) != 0)
      {
        unsigned int j;
        for (j = 0; j < ctx->indent.count; j++) {
          fprintf(f, "%s", ctx->indent.string);
        }
      }
      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, const dns_name_t *name,
      dns_rdataset_t *rdataset, isc_buffer_t *buffer, FILE *f) {
  isc_result_t result;
  uint32_t totallen;
  uint16_t dlen;
  isc_region_t r, r_hdr;

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

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 = (uint16_t)r.length;
  isc_buffer_putuint16(buffer, dlen);
  isc_buffer_copyregion(buffer, &r);
  totallen += sizeof(dlen) + r.length;

  DNS_RDATASET_FOREACH(rdataset) {
    dns_rdata_t rdata = DNS_RDATA_INIT;

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

  /*
   * 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("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, const dns_name_t *owner_name,
       dns_rdatasetiter_t *rdsiter, dns_totext_ctx_t *ctx,
       isc_buffer_t *buffer, FILE *f) {
  isc_result_t result = ISC_R_SUCCESS;
  dns_fixedname_t fixed;
  dns_name_t *name = dns_fixedname_initname(&fixed);

  dns_name_copy(owner_name, name);
  DNS_RDATASETITER_FOREACH(rdsiter) {
    dns_rdataset_t rdataset = DNS_RDATASET_INIT;
    dns_rdatasetiter_current(rdsiter, &rdataset);

    dns_rdataset_getownercase(&rdataset, name);

    if (rdataset.attributes.negative &&
        (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;
    }
  }

  return result;
}

/*
 * 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
dumptostream(dns_dumpctx_t *dctx);

static void
dumpctx_destroy(dns_dumpctx_t *dctx) {
  dctx->magic = 0;
  isc_mutex_destroy(&dctx->lock);
  dns_dbiterator_destroy(&dctx->dbiter);
  if (dctx->version != NULL) {
    dns_db_closeversion(dctx->db, &dctx->version, false);
  }
  dns_db_detach(&dctx->db);
  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);

  isc_refcount_increment(&source->references);

  *target = source;
}

void
dns_dumpctx_detach(dns_dumpctx_t **dctxp) {
  dns_dumpctx_t *dctx;

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

  if (isc_refcount_decrement(&dctx->references) == 1) {
    dumpctx_destroy(dctx);
  }
}

isc_result_t
dns_dumpctx_serial(dns_dumpctx_t *dctx, uint32_t *serial) {
  REQUIRE(DNS_DCTX_VALID(dctx));
  REQUIRE(!dns_db_iscache(dctx->db));

  return dns_db_getsoaserial(dctx->db, dctx->version, serial);
}

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

  atomic_store_release(&dctx->canceled, true);
}

static isc_result_t
flushandsync(FILE *f, isc_result_t result, const char *temp) {
  bool logit = (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(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(ISC_LOGCATEGORY_GENERAL,
              DNS_LOGMODULE_MASTERDUMP, ISC_LOG_ERROR,
              "dumping to stream: flush: %s",
              isc_result_totext(result));
    }
    logit = false;
  }

  if (result == ISC_R_SUCCESS) {
    result = isc_stdio_sync(f);
  }
  if (result != ISC_R_SUCCESS && logit) {
    if (temp != NULL) {
      isc_log_write(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(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;
  bool logit = (result == ISC_R_SUCCESS);

  result = flushandsync(f, result, temp);
  if (result != ISC_R_SUCCESS) {
    logit = false;
  }

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

/*
 * This will run in a libuv threadpool thread.
 */
static void
master_dump_cb(void *data) {
  isc_result_t result = ISC_R_UNSET;
  dns_dumpctx_t *dctx = data;
  REQUIRE(DNS_DCTX_VALID(dctx));

  if (atomic_load_acquire(&dctx->canceled)) {
    result = ISC_R_CANCELED;
  } else {
    result = dumptostream(dctx);
  }

  if (dctx->file != NULL) {
    isc_result_t tresult = ISC_R_UNSET;
    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->result = result;
}

/*
 * This will run in a loop manager thread when the dump is complete.
 */
static void
master_dump_done_cb(void *data) {
  dns_dumpctx_t *dctx = data;

  (dctx->done)(dctx->done_arg, dctx->result);
  dns_dumpctx_detach(&dctx);
}

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));
  *dctx = (dns_dumpctx_t){
    .f = f,
    .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;
  default:
    UNREACHABLE();
  }

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

  dctx->now = isc_stdtime_now();
  dns_db_attach(db, &dctx->db);

  if (dns_db_iscache(dctx->db)) {
    (void)dns_db_getservestalettl(dctx->db,
                &dctx->tctx.serve_stale_ttl);
  } else if (version != NULL) {
    dns_db_attachversion(dctx->db, version, &dctx->version);
  } else {
    dns_db_currentversion(dctx->db, &dctx->version);
  }

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

  isc_mutex_init(&dctx->lock);
  isc_mem_attach(mctx, &dctx->mctx);

  isc_refcount_init(&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);
  }
  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;
  uint32_t rawversion, now32;

  bufmem = isc_mem_get(dctx->mctx, initial_buffer_length);

  isc_buffer_init(&buffer, bufmem, initial_buffer_length);

  switch (dctx->format) {
  case dns_masterformat_text:
    /*
     * If the database has cache semantics, output an
     * RFC2540 $DATE directive so that the TTLs can be
     * adjusted when it is reloaded.  For zones it is not
     * really needed, and it would make the file
     * incompatible with pre-RFC2540 software, so we omit
     * it in the zone case.
     */
    if (dns_db_iscache(dctx->db)) {
      fprintf(dctx->f, "; using a %u second stale ttl\n",
        dctx->tctx.serve_stale_ttl);
      result = dns_time32_totext(dctx->now, &buffer);
      RUNTIME_CHECK(result == ISC_R_SUCCESS);
      isc_buffer_usedregion(&buffer, &r);
      fprintf(dctx->f, "$DATE %.*s\n", (int)r.length,
        (char *)r.base);
    }
    break;
  case dns_masterformat_raw:
    r.base = (unsigned char *)&rawheader;
    r.length = sizeof(rawheader);
    isc_buffer_region(&buffer, &r);
    now32 = dctx->now;
    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:
    UNREACHABLE();
  }

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

static isc_result_t
dumptostream(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 options = DNS_DB_STALEOK;

  if ((dctx->tctx.style.flags & DNS_STYLEFLAG_EXPIRED) != 0) {
    options |= DNS_DB_EXPIREDOK;
  }

  bufmem = isc_mem_get(dctx->mctx, initial_buffer_length);

  isc_buffer_init(&buffer, bufmem, initial_buffer_length);

  name = dns_fixedname_initname(&fixname);

  CHECK(writeheader(dctx));

  DNS_DBITERATOR_FOREACH(dctx->dbiter) {
    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_dbiterator_pause(dctx->dbiter);
    RUNTIME_CHECK(result == ISC_R_SUCCESS);

    result = dns_db_allrdatasets(dctx->db, node, dctx->version,
               options, dctx->now, &rdsiter);
    if (result != ISC_R_SUCCESS) {
      dns_db_detachnode(&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(&node);
      goto cleanup;
    }
    dns_db_detachnode(&node);
  }

  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_dumptostreamasync(isc_mem_t *mctx, dns_db_t *db,
           dns_dbversion_t *version,
           const dns_master_style_t *style, FILE *f,
           isc_loop_t *loop, dns_dumpdonefunc_t done,
           void *done_arg, dns_dumpctx_t **dctxp) {
  dns_dumpctx_t *dctx = NULL;

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

  RETERR(dumpctx_create(mctx, db, version, style, f, &dctx,
            dns_masterformat_text, NULL));
  dctx->done = done;
  dctx->done_arg = done_arg;

  dns_dumpctx_attach(dctx, dctxp);
  isc_work_enqueue(loop, master_dump_cb, master_dump_done_cb, dctx);

  return ISC_R_SUCCESS;
}

isc_result_t
dns_master_dumptostream(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;

  RETERR(dumpctx_create(mctx, db, version, style, f, &dctx, format,
            header));

  result = dumptostream(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, 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);

  CHECK(isc_file_mktemplate(file, tempname, tempnamelen));

  result = isc_file_openunique(tempname, &f);
  if (result != ISC_R_SUCCESS) {
    isc_log_write(ISC_LOGCATEGORY_GENERAL, DNS_LOGMODULE_MASTERDUMP,
            ISC_LOG_ERROR,
            "dumping master file: %s: open: %s", tempname,
            isc_result_totext(result));
    goto cleanup;
  }

#if defined(POSIX_FADV_DONTNEED)
  posix_fadvise(fileno(f), 0, 0, POSIX_FADV_DONTNEED);
#endif

  *tempp = tempname;
  *fp = f;
  return ISC_R_SUCCESS;

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

isc_result_t
dns_master_dumpasync(isc_mem_t *mctx, dns_db_t *db, dns_dbversion_t *version,
         const dns_master_style_t *style, const char *filename,
         isc_loop_t *loop, 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);

  result = opentmp(mctx, filename, &tempname, &f);
  if (result != ISC_R_SUCCESS) {
    goto cleanup_file;
  }

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

  dctx->done = done;
  dctx->done_arg = done_arg;
  dctx->file = file;
  dctx->tmpfile = tempname;

  dns_dumpctx_attach(dctx, dctxp);
  isc_work_enqueue(loop, master_dump_cb, master_dump_done_cb, dctx);

  return ISC_R_SUCCESS;

cleanup_tempname:
  (void)isc_stdio_close(f);
  (void)isc_file_remove(tempname);
  isc_mem_free(mctx, tempname);

cleanup_file:
  isc_mem_free(mctx, file);

  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,
    dns_masterformat_t format, dns_masterrawheader_t *header) {
  FILE *f = NULL;
  isc_result_t result;
  char *tempname;
  dns_dumpctx_t *dctx = NULL;

  RETERR(opentmp(mctx, filename, &tempname, &f));

  CHECK(dumpctx_create(mctx, db, version, style, f, &dctx, format,
           header));

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

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

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

dns_masterstyle_flags_t
dns_master_styleflags(const dns_master_style_t *style) {
  REQUIRE(style != NULL);
  return style->flags;
}

isc_result_t
dns_master_stylecreate(dns_master_style_t **stylep,
           dns_masterstyle_flags_t 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));

  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));
}

Coverage Report

Created: 2026-01-24 06:23