/src/bind9/lib/dns/master.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 <isc/async.h>
#include <isc/atomic.h>
#include <isc/lex.h>
#include <isc/loop.h>
#include <isc/magic.h>
#include <isc/mem.h>
#include <isc/refcount.h>
#include <isc/result.h>
#include <isc/serial.h>
#include <isc/stdio.h>
#include <isc/stdtime.h>
#include <isc/string.h>
#include <isc/util.h>
#include <isc/work.h>

#include <dns/callbacks.h>
#include <dns/fixedname.h>
#include <dns/master.h>
#include <dns/name.h>
#include <dns/rdata.h>
#include <dns/rdataclass.h>
#include <dns/rdatalist.h>
#include <dns/rdataset.h>
#include <dns/rdatastruct.h>
#include <dns/rdatatype.h>
#include <dns/soa.h>
#include <dns/time.h>
#include <dns/ttl.h>

#include "dns/types.h"

/*!
 * Grow the number of dns_rdatalist_t (#RDLSZ) and dns_rdata_t (#RDSZ)
 * structures by these sizes when we need to.
 *
 */
/*% RDLSZ reflects the number of different types with the same name expected. */
#define RDLSZ 32
/*%
 * RDSZ reflects the number of rdata expected at a give name that can fit into
 * 64k.
 */
#define RDSZ 512

#define NBUFS   4
#define MAXWIRESZ 255

/*%
 * Target buffer size and minimum target size.
 * MINTSIZ must be big enough to hold the largest rdata record.
 * \brief
 * TSIZ >= MINTSIZ
 */
#define TSIZ (128 * 1024)
/*%
 * max message size - header - root - type - class - ttl - rdlen
 */
#define MINTSIZ DNS_RDATA_MAXLENGTH
/*%
 * Size for tokens in the presentation format,
 * The largest tokens are the base64 blocks in KEY and CERT records,
 * Largest key allowed is about 1372 bytes but
 * there is no fixed upper bound on CERT records.
 * 2K is too small for some X.509s, 8K is overkill.
 */
#define TOKENSIZ (8 * 1024)

/*%
 * Buffers sizes for $GENERATE.
 */
#define DNS_MASTER_LHS 2048
#define DNS_MASTER_RHS MINTSIZ

#define CHECKNAMESFAIL(x) (((x) & DNS_MASTER_CHECKNAMESFAIL) != 0)

typedef ISC_LIST(dns_rdatalist_t) rdatalist_head_t;

typedef struct dns_incctx dns_incctx_t;

/*%
 * Master file load state.
 */

struct dns_loadctx {
  unsigned int magic;
  isc_mem_t *mctx;
  dns_masterformat_t format;

  dns_rdatacallbacks_t *callbacks;
  dns_loaddonefunc_t done;
  void *done_arg;

  isc_loop_t *loop;

  /* Common methods */
  isc_result_t (*openfile)(dns_loadctx_t *lctx, const char *filename);
  isc_result_t (*load)(dns_loadctx_t *lctx);

  /* Members used by all formats */
  uint32_t maxttl;

  /* Members specific to the text format: */
  isc_lex_t *lex;
  bool keep_lex;
  unsigned int options;
  bool ttl_known;
  bool default_ttl_known;
  bool warn_1035;
  bool warn_tcr;
  bool warn_sigexpired;
  bool seen_include;
  uint32_t ttl;
  uint32_t default_ttl;
  dns_rdataclass_t zclass;
  dns_fixedname_t fixed_top;
  dns_name_t *top; /*%< top of zone */

  /* Members specific to the raw format: */
  FILE *f;
  bool first;
  dns_masterrawheader_t header;

  /* Which fixed buffers we are using? */
  isc_result_t result;

  /* Atomic */
  isc_refcount_t references;
  atomic_bool canceled;

  /* locked by lock */
  dns_incctx_t *inc;
  uint32_t resign;
  isc_stdtime_t now;

  dns_masterincludecb_t include_cb;
  void *include_arg;
};

struct dns_incctx {
  dns_incctx_t *parent;
  dns_name_t *origin;
  dns_name_t *current;
  dns_name_t *glue;
  dns_fixedname_t fixed[NBUFS]; /* working buffers */
  unsigned int in_use[NBUFS];   /* covert to bitmap? */
  int glue_in_use;
  int current_in_use;
  int origin_in_use;
  bool origin_changed;
  bool drop;
  unsigned int glue_line;
  unsigned int current_line;
};

#define DNS_LCTX_MAGIC       ISC_MAGIC('L', 'c', 't', 'x')
#define DNS_LCTX_VALID(lctx) ISC_MAGIC_VALID(lctx, DNS_LCTX_MAGIC)

#define DNS_AS_STR(t) ((t).value.as_textregion.base)

static isc_result_t
openfile_text(dns_loadctx_t *lctx, const char *master_file);

static isc_result_t
load_text(dns_loadctx_t *lctx);

static isc_result_t
openfile_raw(dns_loadctx_t *lctx, const char *master_file);

static isc_result_t
load_raw(dns_loadctx_t *lctx);

static isc_result_t
pushfile(const char *master_file, dns_name_t *origin, dns_loadctx_t *lctx);

static isc_result_t
commit(dns_rdatacallbacks_t *, dns_loadctx_t *, rdatalist_head_t *,
       dns_name_t *, const char *, unsigned int);

static bool
is_glue(rdatalist_head_t *, dns_name_t *);

static dns_rdatalist_t *
grow_rdatalist(int, dns_rdatalist_t *, int, rdatalist_head_t *,
         rdatalist_head_t *, isc_mem_t *mctx);

static dns_rdata_t *
grow_rdata(int, dns_rdata_t *, int, rdatalist_head_t *, rdatalist_head_t *,
     isc_mem_t *);

static void
loadctx_destroy(dns_loadctx_t *lctx);

#define LCTX_MANYERRORS(lctx) (((lctx)->options & DNS_MASTER_MANYERRORS) != 0)

#define GETTOKENERR(lexer, options, token, eol, err)                         \
  do {                                                                 \
    result = gettoken(lexer, options, token, eol, callbacks);    \
    switch (result) {                                            \
    case ISC_R_SUCCESS:                                          \
      break;                                               \
    case ISC_R_NOTFILE:                                          \
      /* Treat "bad" $INCLUDE as eof. */                   \
      if (ictx->parent != NULL && LCTX_MANYERRORS(lctx)) { \
        SETRESULT(lctx, result);                     \
        COMMITALL;                                   \
        lctx->inc = ictx->parent;                    \
        ictx->parent = NULL;                         \
        incctx_destroy(lctx->mctx, ictx);            \
        RUNTIME_CHECK(isc_lex_close(lctx->lex) ==    \
                ISC_R_SUCCESS);                \
        line = isc_lex_getsourceline(lctx->lex);     \
        POST(line);                                  \
        source = isc_lex_getsourcename(lctx->lex);   \
        ictx = lctx->inc;                            \
        continue;                                    \
      }                                                    \
      goto insist_and_cleanup;                             \
    case ISC_R_UNEXPECTED:                                       \
      goto insist_and_cleanup;                             \
    default:                                                     \
      if (MANYERRS(lctx, result)) {                        \
        SETRESULT(lctx, result);                     \
        LOGIT(result);                               \
        read_till_eol = true;                        \
        err goto next_line;                          \
      } else                                               \
        goto log_and_cleanup;                        \
    }                                                            \
    if ((token)->type == isc_tokentype_special) {                \
      result = DNS_R_SYNTAX;                               \
      if (MANYERRS(lctx, result)) {                        \
        SETRESULT(lctx, result);                     \
        LOGIT(result);                               \
        read_till_eol = true;                        \
        goto next_line;                              \
      } else                                               \
        goto log_and_cleanup;                        \
    }                                                            \
  } while (0)
#define GETTOKEN(lexer, options, token, eol) \
  GETTOKENERR(lexer, options, token, eol, {})

#define COMMITALL                                                              \
  do {                                                                   \
    result = commit(callbacks, lctx, &current_list, ictx->current, \
        source, ictx->current_line);                   \
    if (MANYERRS(lctx, result)) {                                  \
      SETRESULT(lctx, result);                               \
    } else if (result != ISC_R_SUCCESS)                            \
      goto insist_and_cleanup;                               \
    result = commit(callbacks, lctx, &glue_list, ictx->glue,       \
        source, ictx->glue_line);                      \
    if (MANYERRS(lctx, result)) {                                  \
      SETRESULT(lctx, result);                               \
    } else if (result != ISC_R_SUCCESS)                            \
      goto insist_and_cleanup;                               \
    rdcount = 0;                                                   \
    rdlcount = 0;                                                  \
    isc_buffer_init(&target, target_mem, target_size);             \
    rdcount_save = rdcount;                                        \
    rdlcount_save = rdlcount;                                      \
  } while (0)

#define WARNUNEXPECTEDEOF(lexer)                                         \
  do {                                                             \
    if (isc_lex_isfile(lexer))                               \
      (*callbacks->warn)(callbacks,                    \
             "%s: file does not end with " \
             "newline",                    \
             source);                      \
  } while (0)

#define EXPECTEOL                                              \
  do {                                                   \
    GETTOKEN(lctx->lex, 0, &token, true);          \
    if (token.type != isc_tokentype_eol) {         \
      isc_lex_ungettoken(lctx->lex, &token); \
      result = DNS_R_EXTRATOKEN;             \
      if (MANYERRS(lctx, result)) {          \
        SETRESULT(lctx, result);       \
        LOGIT(result);                 \
        read_till_eol = true;          \
        break;                         \
      } else if (result != ISC_R_SUCCESS)    \
        goto log_and_cleanup;          \
    }                                              \
  } while (0)

#define MANYERRS(lctx, result)                                     \
  ((result != ISC_R_SUCCESS) && (result != ISC_R_IOERROR) && \
   LCTX_MANYERRORS(lctx))

#define SETRESULT(lctx, r)                     \
  if ((lctx)->result == ISC_R_SUCCESS) { \
    (lctx)->result = r;            \
  }

#define LOGITFILE(result, filename)                                            \
  if (result == ISC_R_INVALIDFILE || result == ISC_R_FILENOTFOUND ||     \
      result == ISC_R_IOERROR || result == ISC_R_TOOMANYOPENFILES ||     \
      result == ISC_R_NOPERM)                                            \
    (*callbacks->error)(callbacks, "%s: %s:%lu: %s: %s",           \
            "dns_master_load", source, line, filename, \
            isc_result_totext(result));                \
  else                                                                   \
    LOGIT(result)

#define LOGIT(result)                                                       \
  (*callbacks->error)(callbacks, "%s: %s:%lu: %s", "dns_master_load", \
          source, line, isc_result_totext(result))

static unsigned char in_addr_arpa_data[] = "\007IN-ADDR\004ARPA";
static dns_name_t const in_addr_arpa = DNS_NAME_INITABSOLUTE(in_addr_arpa_data);

static unsigned char ip6_int_data[] = "\003IP6\003INT";
static dns_name_t const ip6_int = DNS_NAME_INITABSOLUTE(ip6_int_data);

static unsigned char ip6_arpa_data[] = "\003IP6\004ARPA";
static dns_name_t const ip6_arpa = DNS_NAME_INITABSOLUTE(ip6_arpa_data);

static bool
dns_master_isprimary(dns_loadctx_t *lctx) {
  return (lctx->options & DNS_MASTER_ZONE) != 0 &&
         (lctx->options & DNS_MASTER_SECONDARY) == 0 &&
         (lctx->options & DNS_MASTER_KEY) == 0;
}

static isc_result_t
gettoken(isc_lex_t *lex, unsigned int options, isc_token_t *token, bool eol,
   dns_rdatacallbacks_t *callbacks) {
  isc_result_t result;

  options |= ISC_LEXOPT_EOL | ISC_LEXOPT_EOF | ISC_LEXOPT_DNSMULTILINE |
       ISC_LEXOPT_ESCAPE;
  result = isc_lex_gettoken(lex, options, token);
  if (result != ISC_R_SUCCESS) {
    switch (result) {
    default:
      (*callbacks->error)(callbacks,
              "dns_master_load: %s:%lu:"
              " isc_lex_gettoken() failed: %s",
              isc_lex_getsourcename(lex),
              isc_lex_getsourceline(lex),
              isc_result_totext(result));
      return result;
    }
    /*NOTREACHED*/
  }
  if (eol != true) {
    if (token->type == isc_tokentype_eol ||
        token->type == isc_tokentype_eof)
    {
      {
        unsigned long int line;
        const char *what;
        const char *file;
        file = isc_lex_getsourcename(lex);
        line = isc_lex_getsourceline(lex);
        if (token->type == isc_tokentype_eol) {
          line--;
          what = "line";
        } else {
          what = "file";
        }
        (*callbacks->error)(callbacks,
                "dns_master_load: %s:%lu: "
                "unexpected end of %s",
                file, line, what);
        return ISC_R_UNEXPECTEDEND;
      }
    }
  }
  return ISC_R_SUCCESS;
}

ISC_REFCOUNT_DECL(dns_loadctx);
ISC_REFCOUNT_IMPL(dns_loadctx, loadctx_destroy);

static void
incctx_destroy(isc_mem_t *mctx, dns_incctx_t *ictx) {
  dns_incctx_t *parent;

again:
  parent = ictx->parent;
  ictx->parent = NULL;

  isc_mem_put(mctx, ictx, sizeof(*ictx));

  if (parent != NULL) {
    ictx = parent;
    goto again;
  }
}

static void
loadctx_destroy(dns_loadctx_t *lctx) {
  REQUIRE(DNS_LCTX_VALID(lctx));

  isc_refcount_destroy(&lctx->references);

  lctx->magic = 0;
  if (lctx->inc != NULL) {
    incctx_destroy(lctx->mctx, lctx->inc);
  }

  if (lctx->f != NULL) {
    isc_result_t result = isc_stdio_close(lctx->f);
    if (result != ISC_R_SUCCESS) {
      UNEXPECTED_ERROR("isc_stdio_close() failed: %s",
           isc_result_totext(result));
    }
  }

  /* isc_lex_destroy() will close all open streams */
  if (lctx->lex != NULL && !lctx->keep_lex) {
    isc_lex_destroy(&lctx->lex);
  }

  isc_mem_putanddetach(&lctx->mctx, lctx, sizeof(*lctx));
}

static void
incctx_create(isc_mem_t *mctx, dns_name_t *origin, dns_incctx_t **ictxp) {
  dns_incctx_t *ictx;
  isc_region_t r;
  int i;

  ictx = isc_mem_get(mctx, sizeof(*ictx));

  for (i = 0; i < NBUFS; i++) {
    dns_fixedname_init(&ictx->fixed[i]);
    ictx->in_use[i] = false;
  }

  ictx->origin_in_use = 0;
  ictx->origin = dns_fixedname_name(&ictx->fixed[ictx->origin_in_use]);
  ictx->in_use[ictx->origin_in_use] = true;
  dns_name_toregion(origin, &r);
  dns_name_fromregion(ictx->origin, &r);

  ictx->glue = NULL;
  ictx->current = NULL;
  ictx->glue_in_use = -1;
  ictx->current_in_use = -1;
  ictx->parent = NULL;
  ictx->drop = false;
  ictx->glue_line = 0;
  ictx->current_line = 0;
  ictx->origin_changed = true;

  *ictxp = ictx;
}

static void
loadctx_create(dns_masterformat_t format, isc_mem_t *mctx, unsigned int options,
         uint32_t resign, dns_name_t *top, dns_rdataclass_t zclass,
         dns_name_t *origin, dns_rdatacallbacks_t *callbacks,
         dns_loaddonefunc_t done, void *done_arg,
         dns_masterincludecb_t include_cb, void *include_arg,
         isc_lex_t *lex, dns_loadctx_t **lctxp) {
  dns_loadctx_t *lctx = NULL;
  isc_region_t r;

  REQUIRE(lctxp != NULL && *lctxp == NULL);
  REQUIRE(callbacks != NULL);
  REQUIRE(callbacks->update != NULL);
  REQUIRE(callbacks->error != NULL);
  REQUIRE(callbacks->warn != NULL);
  REQUIRE(mctx != NULL);
  REQUIRE(dns_name_isabsolute(top));
  REQUIRE(dns_name_isabsolute(origin));

  lctx = isc_mem_get(mctx, sizeof(*lctx));
  *lctx = (dns_loadctx_t){
    .format = format,
    .ttl_known = ((options & DNS_MASTER_NOTTL) != 0),
    .default_ttl_known = ((options & DNS_MASTER_NOTTL) != 0),
    .warn_1035 = true,
    .warn_sigexpired = true,
    .options = options,
    .zclass = zclass,
    .resign = resign,
    .include_cb = include_cb,
    .include_arg = include_arg,
    .first = true,
    .done = done,
    .callbacks = callbacks,
    .done_arg = done_arg,
  };

  incctx_create(mctx, origin, &lctx->inc);

  switch (format) {
  case dns_masterformat_text:
    lctx->openfile = openfile_text;
    lctx->load = load_text;
    break;
  case dns_masterformat_raw:
    lctx->openfile = openfile_raw;
    lctx->load = load_raw;
    break;
  default:
    UNREACHABLE();
  }

  if (lex != NULL) {
    lctx->lex = lex;
    lctx->keep_lex = true;
  } else {
    isc_lexspecials_t specials;
    lctx->lex = NULL;
    isc_lex_create(mctx, TOKENSIZ, &lctx->lex);
    lctx->keep_lex = false;
    /*
     * If specials change update dns_test_rdatafromstring()
     * in lib/dns/tests/dnstest.c.
     */
    memset(specials, 0, sizeof(specials));
    specials[0] = 1;
    specials['('] = 1;
    specials[')'] = 1;
    specials['"'] = 1;
    isc_lex_setspecials(lctx->lex, specials);
    isc_lex_setcomments(lctx->lex, ISC_LEXCOMMENT_DNSMASTERFILE);
  }

  lctx->now = isc_stdtime_now();

  lctx->top = dns_fixedname_initname(&lctx->fixed_top);
  dns_name_toregion(top, &r);
  dns_name_fromregion(lctx->top, &r);

  dns_master_initrawheader(&lctx->header);

  isc_refcount_init(&lctx->references, 1); /* Implicit attach. */
  isc_mem_attach(mctx, &lctx->mctx);

  lctx->magic = DNS_LCTX_MAGIC;
  *lctxp = lctx;
  return;
}

static const char *hex = "0123456789abcdef0123456789ABCDEF";

/*%
 * Convert value into a nibble sequence from least significant to most
 * significant nibble.  Zero fill upper most significant nibbles if
 * required to make the width.
 *
 * Returns the number of characters that should have been written without
 * counting the terminating NUL.
 */
static unsigned int
nibbles(char *numbuf, size_t length, unsigned int width, char mode,
  unsigned int value) {
  unsigned int count = 0;

  /*
   * This reserve space for the NUL string terminator.
   */
  if (length > 0U) {
    *numbuf = '\0';
    length--;
  }
  do {
    char val = hex[(value & 0x0f) + ((mode == 'n') ? 0 : 16)];
    value >>= 4;
    if (length > 0U) {
      *numbuf++ = val;
      *numbuf = '\0';
      length--;
    }
    if (width > 0) {
      width--;
    }
    count++;
    /*
     * If width is non zero then we need to add a label separator.
     * If value is non zero then we need to add another label and
     * that requires a label separator.
     */
    if (width > 0 || value != 0) {
      if (length > 0U) {
        *numbuf++ = '.';
        *numbuf = '\0';
        length--;
      }
      if (width > 0) {
        width--;
      }
      count++;
    }
  } while (value != 0 || width > 0);
  return count;
}

static isc_result_t
genname(char *name, int it, char *buffer, size_t length) {
  char fmt[sizeof("%04000000000d")];
  char numbuf[128];
  char *cp;
  char mode[2] = { 0 };
  char brace[2] = { 0 };
  char comma1[2] = { 0 };
  char comma2[2] = { 0 };
  int delta = 0;
  isc_textregion_t r;
  unsigned int n;
  unsigned int width;
  bool nibblemode;

  r.base = buffer;
  r.length = (unsigned int)length;

  while (*name != '\0') {
    if (*name == '$') {
      name++;
      if (*name == '$') {
        if (r.length == 0) {
          return ISC_R_NOSPACE;
        }
        r.base[0] = *name++;
        isc_textregion_consume(&r, 1);
        continue;
      }
      nibblemode = false;
      strlcpy(fmt, "%d", sizeof(fmt));
      /* Get format specifier. */
      if (*name == '{') {
        n = sscanf(name,
             "{%d%1[,}]%u%1[,}]%1[doxXnN]%1[}]",
             &delta, comma1, &width, comma2, mode,
             brace);
        if (n < 2 || n > 6) {
          return DNS_R_SYNTAX;
        }
        if (comma1[0] == '}') {
          /* %{delta} */
        } else if (comma1[0] == ',' && comma2[0] == '}')
        {
          /* %{delta,width} */
          n = snprintf(fmt, sizeof(fmt), "%%0%ud",
                 width);
        } else if (comma1[0] == ',' &&
             comma2[0] == ',' && mode[0] != 0 &&
             brace[0] == '}')
        {
          /* %{delta,width,format} */
          if (mode[0] == 'n' || mode[0] == 'N') {
            nibblemode = true;
          }
          n = snprintf(fmt, sizeof(fmt),
                 "%%0%u%c", width, mode[0]);
        } else {
          return DNS_R_SYNTAX;
        }
        if (n >= sizeof(fmt)) {
          return ISC_R_NOSPACE;
        }
        /* Skip past closing brace. */
        while (*name != '\0' && *name++ != '}') {
          continue;
        }
      }
      /*
       * 'it' is >= 0 so we don't need to check for
       * underflow.
       */
      if (it > 0 && delta > INT_MAX - it) {
        return ISC_R_RANGE;
      }
      if (nibblemode) {
        n = nibbles(numbuf, sizeof(numbuf), width,
              mode[0], it + delta);
      } else {
        n = snprintf(numbuf, sizeof(numbuf), fmt,
               it + delta);
      }
      if (n >= sizeof(numbuf)) {
        return ISC_R_NOSPACE;
      }
      cp = numbuf;
      while (*cp != '\0') {
        if (r.length == 0) {
          return ISC_R_NOSPACE;
        }
        r.base[0] = *cp++;
        isc_textregion_consume(&r, 1);
      }
    } else if (*name == '\\') {
      if (r.length == 0) {
        return ISC_R_NOSPACE;
      }
      r.base[0] = *name++;
      isc_textregion_consume(&r, 1);
      if (*name == '\0') {
        continue;
      }
      if (r.length == 0) {
        return ISC_R_NOSPACE;
      }
      r.base[0] = *name++;
      isc_textregion_consume(&r, 1);
    } else {
      if (r.length == 0) {
        return ISC_R_NOSPACE;
      }
      r.base[0] = *name++;
      isc_textregion_consume(&r, 1);
    }
  }
  if (r.length == 0) {
    return ISC_R_NOSPACE;
  }
  r.base[0] = '\0';
  return ISC_R_SUCCESS;
}

static isc_result_t
generate(dns_loadctx_t *lctx, char *range, char *lhs, char *gtype, char *rhs,
   const char *source, unsigned int line) {
  char *target_mem = NULL;
  char *lhsbuf = NULL;
  char *rhsbuf = NULL;
  dns_fixedname_t ownerfixed;
  dns_name_t *owner;
  dns_rdata_t rdata = DNS_RDATA_INIT;
  dns_rdatacallbacks_t *callbacks;
  dns_rdatalist_t rdatalist;
  dns_rdatatype_t type;
  rdatalist_head_t head;
  int target_size = MINTSIZ; /* only one rdata at a time */
  isc_buffer_t buffer;
  isc_buffer_t target;
  isc_result_t result;
  isc_textregion_t r;
  int n, start, stop, step = 0;
  unsigned int i;
  dns_incctx_t *ictx;
  char dummy[2];

  ictx = lctx->inc;
  callbacks = lctx->callbacks;
  owner = dns_fixedname_initname(&ownerfixed);
  ISC_LIST_INIT(head);

  target_mem = isc_mem_get(lctx->mctx, target_size);
  rhsbuf = isc_mem_get(lctx->mctx, DNS_MASTER_RHS);
  lhsbuf = isc_mem_get(lctx->mctx, DNS_MASTER_LHS);
  isc_buffer_init(&target, target_mem, target_size);

  n = sscanf(range, "%d-%d%1[/]%d", &start, &stop, dummy, &step);
  if ((n != 2 && n != 4) || (start < 0) || (stop < 0) ||
      (n == 4 && step < 1) || (stop < start))
  {
    (*callbacks->error)(callbacks, "%s: %s:%lu: invalid range '%s'",
            "$GENERATE", source, line, range);
    result = DNS_R_SYNTAX;
    goto insist_cleanup;
  }
  if (n == 2) {
    step = 1;
  }

  /*
   * Get type.
   */
  r.base = gtype;
  r.length = strlen(gtype);
  result = dns_rdatatype_fromtext(&type, &r);
  if (result != ISC_R_SUCCESS) {
    (*callbacks->error)(callbacks,
            "%s: %s:%lu: unknown RR type '%s'",
            "$GENERATE", source, line, gtype);
    goto insist_cleanup;
  }

  /*
   * RFC2930: TKEY and TSIG are not allowed to be loaded
   * from master files.
   */
  if (dns_master_isprimary(lctx) && dns_rdatatype_ismeta(type)) {
    (*callbacks->error)(callbacks, "%s: %s:%lu: meta RR type '%s'",
            "$GENERATE", source, line, gtype);
    result = DNS_R_METATYPE;
    goto insist_cleanup;
  }

  for (i = start; i <= (unsigned int)stop; i += step) {
    result = genname(lhs, i, lhsbuf, DNS_MASTER_LHS);
    if (result != ISC_R_SUCCESS) {
      goto error_cleanup;
    }
    result = genname(rhs, i, rhsbuf, DNS_MASTER_RHS);
    if (result != ISC_R_SUCCESS) {
      goto error_cleanup;
    }

    isc_buffer_init(&buffer, lhsbuf, strlen(lhsbuf));
    isc_buffer_add(&buffer, strlen(lhsbuf));
    isc_buffer_setactive(&buffer, strlen(lhsbuf));
    result = dns_name_fromtext(owner, &buffer, ictx->origin, 0);
    if (result != ISC_R_SUCCESS) {
      goto error_cleanup;
    }

    if (dns_master_isprimary(lctx) &&
        !dns_name_issubdomain(owner, lctx->top))
    {
      char namebuf[DNS_NAME_FORMATSIZE];
      dns_name_format(owner, namebuf, sizeof(namebuf));
      /*
       * Ignore out-of-zone data.
       */
      (*callbacks->warn)(callbacks,
             "%s:%lu: "
             "ignoring out-of-zone data (%s)",
             source, line, namebuf);
      continue;
    }

    isc_buffer_init(&buffer, rhsbuf, strlen(rhsbuf));
    isc_buffer_add(&buffer, strlen(rhsbuf));
    isc_buffer_setactive(&buffer, strlen(rhsbuf));

    result = isc_lex_openbuffer(lctx->lex, &buffer);
    if (result != ISC_R_SUCCESS) {
      goto error_cleanup;
    }

    isc_buffer_init(&target, target_mem, target_size);
    result = dns_rdata_fromtext(&rdata, lctx->zclass, type,
              lctx->lex, ictx->origin, 0,
              lctx->mctx, &target, callbacks);
    RUNTIME_CHECK(isc_lex_close(lctx->lex) == ISC_R_SUCCESS);
    if (result != ISC_R_SUCCESS) {
      goto error_cleanup;
    }

    dns_rdatalist_init(&rdatalist);
    rdatalist.type = type;
    rdatalist.rdclass = lctx->zclass;
    rdatalist.ttl = lctx->ttl;
    ISC_LIST_PREPEND(head, &rdatalist, link);
    ISC_LIST_APPEND(rdatalist.rdata, &rdata, link);
    result = commit(callbacks, lctx, &head, owner, source, line);
    ISC_LIST_UNLINK(rdatalist.rdata, &rdata, link);
    if (result != ISC_R_SUCCESS) {
      goto error_cleanup;
    }
    dns_rdata_reset(&rdata);
  }
  result = ISC_R_SUCCESS;
  goto cleanup;

error_cleanup:
  (*callbacks->error)(callbacks, "$GENERATE: %s:%lu: %s", source, line,
          isc_result_totext(result));

insist_cleanup:
  INSIST(result != ISC_R_SUCCESS);

cleanup:
  if (target_mem != NULL) {
    isc_mem_put(lctx->mctx, target_mem, target_size);
  }
  if (lhsbuf != NULL) {
    isc_mem_put(lctx->mctx, lhsbuf, DNS_MASTER_LHS);
  }
  if (rhsbuf != NULL) {
    isc_mem_put(lctx->mctx, rhsbuf, DNS_MASTER_RHS);
  }
  return result;
}

static void
limit_ttl(dns_rdatacallbacks_t *callbacks, const char *source,
    unsigned int line, uint32_t *ttlp) {
  if (*ttlp > 0x7fffffffUL) {
    (callbacks->warn)(callbacks,
          "%s: %s:%lu: "
          "$TTL %lu > MAXTTL, "
          "setting $TTL to 0",
          "dns_master_load", source, line, *ttlp);
    *ttlp = 0;
  }
}

static isc_result_t
check_ns(dns_loadctx_t *lctx, isc_token_t *token, const char *source,
   unsigned long line) {
  char *tmp = NULL;
  isc_result_t result = ISC_R_SUCCESS;
  void (*callback)(struct dns_rdatacallbacks *, const char *, ...);

  if ((lctx->options & DNS_MASTER_FATALNS) != 0) {
    callback = lctx->callbacks->error;
  } else {
    callback = lctx->callbacks->warn;
  }

  if (token->type == isc_tokentype_string) {
    struct in_addr addr;
    struct in6_addr addr6;

    tmp = isc_mem_strdup(lctx->mctx, DNS_AS_STR(*token));
    /*
     * Catch both "1.2.3.4" and "1.2.3.4."
     */
    if (tmp[strlen(tmp) - 1] == '.') {
      tmp[strlen(tmp) - 1] = '\0';
    }
    if (inet_pton(AF_INET, tmp, &addr) == 1 ||
        inet_pton(AF_INET6, tmp, &addr6) == 1)
    {
      result = DNS_R_NSISADDRESS;
    }
  }
  if (result != ISC_R_SUCCESS) {
    (*callback)(lctx->callbacks,
          "%s:%lu: NS record '%s' "
          "appears to be an address",
          source, line, DNS_AS_STR(*token));
  }
  if (tmp != NULL) {
    isc_mem_free(lctx->mctx, tmp);
  }
  return result;
}

static void
check_wildcard(dns_incctx_t *ictx, const char *source, unsigned long line,
         dns_rdatacallbacks_t *callbacks) {
  dns_name_t *name;

  name = (ictx->glue != NULL) ? ictx->glue : ictx->current;
  if (dns_name_internalwildcard(name)) {
    char namebuf[DNS_NAME_FORMATSIZE];

    dns_name_format(name, namebuf, sizeof(namebuf));
    (*callbacks->warn)(callbacks,
           "%s:%lu: warning: ownername "
           "'%s' contains an non-terminal wildcard",
           source, line, namebuf);
  }
}

static isc_result_t
openfile_text(dns_loadctx_t *lctx, const char *master_file) {
  return isc_lex_openfile(lctx->lex, master_file);
}

static int
find_free_name(dns_incctx_t *incctx) {
  int i;

  for (i = 0; i < (NBUFS - 1); i++) {
    if (!incctx->in_use[i]) {
      break;
    }
  }
  INSIST(!incctx->in_use[i]);
  return i;
}

static isc_result_t
load_text(dns_loadctx_t *lctx) {
  dns_rdataclass_t rdclass;
  dns_rdatatype_t type, covers;
  uint32_t ttl_offset = 0;
  dns_name_t *new_name = NULL;
  bool current_has_delegation = false;
  bool finish_origin = false;
  bool finish_include = false;
  bool read_till_eol = false;
  bool initialws;
  char *include_file = NULL;
  isc_token_t token;
  isc_result_t result = ISC_R_UNEXPECTED;
  rdatalist_head_t glue_list;
  rdatalist_head_t current_list;
  dns_rdatalist_t *rdatalist = NULL;
  dns_rdatalist_t *new_rdatalist = NULL;
  int rdlcount = 0;
  int rdlcount_save = 0;
  int rdatalist_size = 0;
  isc_buffer_t buffer;
  isc_buffer_t target;
  isc_buffer_t target_ft;
  isc_buffer_t target_save;
  dns_rdata_t *rdata = NULL;
  dns_rdata_t *new_rdata = NULL;
  int rdcount = 0;
  int rdcount_save = 0;
  int rdata_size = 0;
  unsigned char *target_mem = NULL;
  int target_size = TSIZ;
  int new_in_use;
  isc_mem_t *mctx = NULL;
  dns_rdatacallbacks_t *callbacks = NULL;
  dns_incctx_t *ictx = NULL;
  char *range = NULL;
  char *lhs = NULL;
  char *gtype = NULL;
  char *rhs = NULL;
  const char *source = NULL;
  unsigned long line = 0;
  bool explicit_ttl;
  char classname1[DNS_RDATACLASS_FORMATSIZE];
  char classname2[DNS_RDATACLASS_FORMATSIZE];
  unsigned int options = 0;

  REQUIRE(DNS_LCTX_VALID(lctx));
  callbacks = lctx->callbacks;
  mctx = lctx->mctx;
  ictx = lctx->inc;

  ISC_LIST_INIT(glue_list);
  ISC_LIST_INIT(current_list);

  /*
   * Allocate target_size of buffer space.  This is greater than twice
   * the maximum individual RR data size.
   */
  target_mem = isc_mem_get(mctx, target_size);
  isc_buffer_init(&target, target_mem, target_size);
  target_save = target;

  /* open a database transaction */
  if (callbacks->setup != NULL) {
    callbacks->setup(callbacks->add_private);
  }

  if ((lctx->options & DNS_MASTER_CHECKNAMES) != 0) {
    options |= DNS_RDATA_CHECKNAMES;
  }
  if ((lctx->options & DNS_MASTER_CHECKNAMESFAIL) != 0) {
    options |= DNS_RDATA_CHECKNAMESFAIL;
  }
  if ((lctx->options & DNS_MASTER_CHECKMX) != 0) {
    options |= DNS_RDATA_CHECKMX;
  }
  if ((lctx->options & DNS_MASTER_CHECKMXFAIL) != 0) {
    options |= DNS_RDATA_CHECKMXFAIL;
  }
  source = isc_lex_getsourcename(lctx->lex);
  while (true) {
    dns_rdatalist_t *this = NULL;

    if (atomic_load_acquire(&lctx->canceled)) {
      result = ISC_R_CANCELED;
      goto log_and_cleanup;
    }

    initialws = false;
    line = isc_lex_getsourceline(lctx->lex);
    GETTOKEN(lctx->lex, ISC_LEXOPT_INITIALWS | ISC_LEXOPT_QSTRING,
       &token, true);
    line = isc_lex_getsourceline(lctx->lex);

    if (token.type == isc_tokentype_eof) {
      if (read_till_eol) {
        WARNUNEXPECTEDEOF(lctx->lex);
      }
      /* Pop the include stack? */
      if (ictx->parent != NULL) {
        COMMITALL;
        lctx->inc = ictx->parent;
        ictx->parent = NULL;
        incctx_destroy(lctx->mctx, ictx);
        RUNTIME_CHECK(isc_lex_close(lctx->lex) ==
                ISC_R_SUCCESS);
        line = isc_lex_getsourceline(lctx->lex);
        POST(line);
        source = isc_lex_getsourcename(lctx->lex);
        ictx = lctx->inc;
        continue;
      }
      break;
    }

    if (token.type == isc_tokentype_eol) {
      read_till_eol = false;
      continue; /* blank line */
    }

    if (read_till_eol) {
      continue;
    }

    if (token.type == isc_tokentype_initialws) {
      /*
       * Still working on the same name.
       */
      initialws = true;
    } else if (token.type == isc_tokentype_string ||
         token.type == isc_tokentype_qstring)
    {
      /*
       * "$" Support.
       *
       * "$ORIGIN" and "$INCLUDE" can both take domain names.
       * The processing of "$ORIGIN" and "$INCLUDE" extends
       * across the normal domain name processing.
       */

      if (strcasecmp(DNS_AS_STR(token), "$ORIGIN") == 0) {
        GETTOKEN(lctx->lex, 0, &token, false);
        finish_origin = true;
      } else if (strcasecmp(DNS_AS_STR(token), "$TTL") == 0) {
        GETTOKENERR(lctx->lex, 0, &token, false,
              lctx->ttl = 0;
              lctx->default_ttl_known = true;);
        result = dns_ttl_fromtext(
          &token.value.as_textregion, &lctx->ttl);
        if (MANYERRS(lctx, result)) {
          SETRESULT(lctx, result);
          lctx->ttl = 0;
        } else if (result != ISC_R_SUCCESS) {
          goto insist_and_cleanup;
        }
        limit_ttl(callbacks, source, line, &lctx->ttl);
        lctx->default_ttl = lctx->ttl;
        lctx->default_ttl_known = true;
        EXPECTEOL;
        continue;
      } else if (strcasecmp(DNS_AS_STR(token), "$INCLUDE") ==
           0)
      {
        COMMITALL;
        if (ttl_offset != 0) {
          (callbacks->error)(callbacks,
                 "%s: %s:%lu: "
                 "$INCLUDE "
                 "may not be used "
                 "with $DATE",
                 "dns_master_load",
                 source, line);
          result = DNS_R_SYNTAX;
          goto insist_and_cleanup;
        }
        GETTOKEN(lctx->lex, ISC_LEXOPT_QSTRING, &token,
           false);
        if (include_file != NULL) {
          isc_mem_free(mctx, include_file);
        }
        include_file =
          isc_mem_strdup(mctx, DNS_AS_STR(token));
        GETTOKEN(lctx->lex, 0, &token, true);

        if (token.type == isc_tokentype_eol ||
            token.type == isc_tokentype_eof)
        {
          if (token.type == isc_tokentype_eof) {
            WARNUNEXPECTEDEOF(lctx->lex);
          }
          /*
           * No origin field.
           */
          result = pushfile(include_file,
                ictx->origin, lctx);
          if (MANYERRS(lctx, result)) {
            SETRESULT(lctx, result);
            LOGITFILE(result, include_file);
            continue;
          } else if (result != ISC_R_SUCCESS) {
            LOGITFILE(result, include_file);
            goto insist_and_cleanup;
          }
          ictx = lctx->inc;
          source = isc_lex_getsourcename(
            lctx->lex);
          line = isc_lex_getsourceline(lctx->lex);
          POST(line);
          continue;
        }
        /*
         * There is an origin field.  Fall through
         * to domain name processing code and do
         * the actual inclusion later.
         */
        finish_include = true;
      } else if (strcasecmp(DNS_AS_STR(token), "$DATE") == 0)
      {
        int64_t dump_time64;
        isc_stdtime_t dump_time;
        isc_stdtime_t current_time = isc_stdtime_now();
        GETTOKEN(lctx->lex, 0, &token, false);
        result = dns_time64_fromtext(DNS_AS_STR(token),
                   &dump_time64);
        if (MANYERRS(lctx, result)) {
          SETRESULT(lctx, result);
          LOGIT(result);
          dump_time64 = 0;
        } else if (result != ISC_R_SUCCESS) {
          goto log_and_cleanup;
        }
        dump_time = (isc_stdtime_t)dump_time64;
        if (dump_time != dump_time64) {
          UNEXPECTED_ERROR("%s: %s:%lu: $DATE "
               "outside epoch",
               "dns_master_load",
               source, line);
          result = ISC_R_UNEXPECTED;
          goto insist_and_cleanup;
        }
        if (dump_time > current_time) {
          UNEXPECTED_ERROR("%s: %s:%lu: "
               "$DATE in future, "
               "using current date",
               "dns_master_load",
               source, line);
          dump_time = current_time;
        }
        ttl_offset = current_time - dump_time;
        EXPECTEOL;
        continue;
      } else if (strcasecmp(DNS_AS_STR(token), "$GENERATE") ==
           0)
      {
        /*
         * Lazy cleanup.
         */
        if (range != NULL) {
          isc_mem_free(mctx, range);
        }
        if (lhs != NULL) {
          isc_mem_free(mctx, lhs);
        }
        if (gtype != NULL) {
          isc_mem_free(mctx, gtype);
        }
        if (rhs != NULL) {
          isc_mem_free(mctx, rhs);
        }
        range = lhs = gtype = rhs = NULL;
        /* RANGE */
        GETTOKEN(lctx->lex, 0, &token, false);
        range = isc_mem_strdup(mctx, DNS_AS_STR(token));
        /* LHS */
        GETTOKEN(lctx->lex, 0, &token, false);
        lhs = isc_mem_strdup(mctx, DNS_AS_STR(token));
        rdclass = 0;
        explicit_ttl = false;
        /* CLASS? */
        GETTOKEN(lctx->lex, 0, &token, false);
        if (dns_rdataclass_fromtext(
              &rdclass,
              &token.value.as_textregion) ==
            ISC_R_SUCCESS)
        {
          GETTOKEN(lctx->lex, 0, &token, false);
        }
        /* TTL? */
        if (dns_ttl_fromtext(&token.value.as_textregion,
                 &lctx->ttl) ==
            ISC_R_SUCCESS)
        {
          limit_ttl(callbacks, source, line,
              &lctx->ttl);
          lctx->ttl_known = true;
          explicit_ttl = true;
          GETTOKEN(lctx->lex, 0, &token, false);
        }
        /* CLASS? */
        if (rdclass == 0 &&
            dns_rdataclass_fromtext(
              &rdclass,
              &token.value.as_textregion) ==
              ISC_R_SUCCESS)
        {
          GETTOKEN(lctx->lex, 0, &token, false);
        }
        /* TYPE */
        gtype = isc_mem_strdup(mctx, DNS_AS_STR(token));
        /* RHS */
        GETTOKEN(lctx->lex, ISC_LEXOPT_QSTRING, &token,
           false);
        rhs = isc_mem_strdup(mctx, DNS_AS_STR(token));
        if (!lctx->ttl_known &&
            !lctx->default_ttl_known)
        {
          (*callbacks->error)(callbacks,
                  "%s: %s:%lu: no "
                  "TTL specified",
                  "dns_master_load",
                  source, line);
          result = DNS_R_NOTTL;
          if (MANYERRS(lctx, result)) {
            SETRESULT(lctx, result);
            lctx->ttl = 0;
          } else {
            goto insist_and_cleanup;
          }
        } else if (!explicit_ttl &&
             lctx->default_ttl_known)
        {
          lctx->ttl = lctx->default_ttl;
        }
        /*
         * If the class specified does not match the
         * zone's class print out a error message and
         * exit.
         */
        if (rdclass != 0 && rdclass != lctx->zclass) {
          goto bad_class;
        }
        result = generate(lctx, range, lhs, gtype, rhs,
              source, line);
        if (MANYERRS(lctx, result)) {
          SETRESULT(lctx, result);
        } else if (result != ISC_R_SUCCESS) {
          goto insist_and_cleanup;
        }
        EXPECTEOL;
        continue;
      } else if (strncasecmp(DNS_AS_STR(token), "$", 1) == 0)
      {
        (callbacks->error)(callbacks,
               "%s: %s:%lu: "
               "unknown $ directive '%s'",
               "dns_master_load", source,
               line, DNS_AS_STR(token));
        result = DNS_R_SYNTAX;
        if (MANYERRS(lctx, result)) {
          SETRESULT(lctx, result);
        } else {
          goto insist_and_cleanup;
        }
      }

      /*
       * Normal processing resumes.
       */
      new_in_use = find_free_name(ictx);
      new_name = dns_fixedname_initname(
        &ictx->fixed[new_in_use]);
      isc_buffer_init(&buffer, token.value.as_region.base,
          token.value.as_region.length);
      isc_buffer_add(&buffer, token.value.as_region.length);
      isc_buffer_setactive(&buffer,
               token.value.as_region.length);
      result = dns_name_fromtext(new_name, &buffer,
               ictx->origin, 0);
      if (MANYERRS(lctx, result)) {
        SETRESULT(lctx, result);
        LOGIT(result);
        read_till_eol = true;
        continue;
      } else if (result != ISC_R_SUCCESS) {
        goto log_and_cleanup;
      }

      /*
       * Finish $ORIGIN / $INCLUDE processing if required.
       */
      if (finish_origin) {
        if (ictx->origin_in_use != -1) {
          ictx->in_use[ictx->origin_in_use] =
            false;
        }
        ictx->origin_in_use = new_in_use;
        ictx->in_use[ictx->origin_in_use] = true;
        ictx->origin = new_name;
        ictx->origin_changed = true;
        finish_origin = false;
        EXPECTEOL;
        continue;
      }
      if (finish_include) {
        finish_include = false;
        EXPECTEOL;
        result = pushfile(include_file, new_name, lctx);
        if (MANYERRS(lctx, result)) {
          SETRESULT(lctx, result);
          LOGITFILE(result, include_file);
          continue;
        } else if (result != ISC_R_SUCCESS) {
          LOGITFILE(result, include_file);
          goto insist_and_cleanup;
        }
        ictx = lctx->inc;
        ictx->origin_changed = true;
        source = isc_lex_getsourcename(lctx->lex);
        line = isc_lex_getsourceline(lctx->lex);
        POST(line);
        continue;
      }

      /*
       * "$" Processing Finished
       */

      /*
       * If we are processing glue and the new name does
       * not match the current glue name, commit the glue
       * and pop stacks leaving us in 'normal' processing
       * state.  Linked lists are undone by commit().
       */
      if (ictx->glue != NULL &&
          !dns_name_caseequal(ictx->glue, new_name))
      {
        result = commit(callbacks, lctx, &glue_list,
            ictx->glue, source,
            ictx->glue_line);
        if (MANYERRS(lctx, result)) {
          SETRESULT(lctx, result);
        } else if (result != ISC_R_SUCCESS) {
          goto insist_and_cleanup;
        }
        if (ictx->glue_in_use != -1) {
          ictx->in_use[ictx->glue_in_use] = false;
        }
        ictx->glue_in_use = -1;
        ictx->glue = NULL;
        rdcount = rdcount_save;
        rdlcount = rdlcount_save;
        target = target_save;
      }

      /*
       * If we are in 'normal' processing state and the new
       * name does not match the current name, see if the
       * new name is for glue and treat it as such,
       * otherwise we have a new name so commit what we
       * have.
       */
      if ((ictx->glue == NULL) &&
          (ictx->current == NULL ||
           !dns_name_caseequal(ictx->current, new_name)))
      {
        if (current_has_delegation &&
            is_glue(&current_list, new_name))
        {
          rdcount_save = rdcount;
          rdlcount_save = rdlcount;
          target_save = target;
          ictx->glue = new_name;
          ictx->glue_in_use = new_in_use;
          ictx->in_use[ictx->glue_in_use] = true;
        } else {
          result = commit(callbacks, lctx,
              &current_list,
              ictx->current, source,
              ictx->current_line);
          if (MANYERRS(lctx, result)) {
            SETRESULT(lctx, result);
          } else if (result != ISC_R_SUCCESS) {
            goto insist_and_cleanup;
          }
          rdcount = 0;
          rdlcount = 0;
          if (ictx->current_in_use != -1) {
            ictx->in_use
              [ictx->current_in_use] =
              false;
          }
          ictx->current_in_use = new_in_use;
          ictx->in_use[ictx->current_in_use] =
            true;
          ictx->current = new_name;
          current_has_delegation = false;
          isc_buffer_init(&target, target_mem,
              target_size);
        }
        /*
         * Check for internal wildcards.
         */
        if ((lctx->options &
             DNS_MASTER_CHECKWILDCARD) != 0)
        {
          check_wildcard(ictx, source, line,
                   callbacks);
        }
      }
      if (dns_master_isprimary(lctx) &&
          !dns_name_issubdomain(new_name, lctx->top))
      {
        char namebuf[DNS_NAME_FORMATSIZE];
        dns_name_format(new_name, namebuf,
            sizeof(namebuf));
        /*
         * Ignore out-of-zone data.
         */
        (*callbacks->warn)(callbacks,
               "%s:%lu: "
               "ignoring out-of-zone data "
               "(%s)",
               source, line, namebuf);
        ictx->drop = true;
      } else {
        ictx->drop = false;
      }
    } else {
      UNEXPECTED_ERROR("%s:%lu: isc_lex_gettoken() returned "
           "unexpected token type (%d)",
           source, line, token.type);
      result = ISC_R_UNEXPECTED;
      if (MANYERRS(lctx, result)) {
        SETRESULT(lctx, result);
        LOGIT(result);
        continue;
      } else {
        goto insist_and_cleanup;
      }
    }

    /*
     * Find TTL, class and type.  Both TTL and class are optional
     * and may occur in any order if they exist. TTL and class
     * come before type which must exist.
     *
     * [<TTL>] [<class>] <type> <RDATA>
     * [<class>] [<TTL>] <type> <RDATA>
     */

    type = dns_rdatatype_none;
    rdclass = 0;

    GETTOKEN(lctx->lex, 0, &token, initialws);

    if (initialws) {
      if (token.type == isc_tokentype_eol) {
        read_till_eol = false;
        continue; /* blank line */
      }

      if (token.type == isc_tokentype_eof) {
        WARNUNEXPECTEDEOF(lctx->lex);
        read_till_eol = false;
        isc_lex_ungettoken(lctx->lex, &token);
        continue;
      }

      if (ictx->current == NULL) {
        (*callbacks->error)(callbacks,
                "%s:%lu: no current owner "
                "name",
                source, line);
        result = DNS_R_NOOWNER;
        if (MANYERRS(lctx, result)) {
          SETRESULT(lctx, result);
          read_till_eol = true;
          continue;
        } else {
          goto insist_and_cleanup;
        }
      }

      if (ictx->origin_changed) {
        char cbuf[DNS_NAME_FORMATSIZE];
        char obuf[DNS_NAME_FORMATSIZE];
        dns_name_format(ictx->current, cbuf,
            sizeof(cbuf));
        dns_name_format(ictx->origin, obuf,
            sizeof(obuf));
        (*callbacks->warn)(callbacks,
               "%s:%lu: record with "
               "inherited "
               "owner (%s) immediately "
               "after "
               "$ORIGIN (%s)",
               source, line, cbuf, obuf);
      }
    }

    ictx->origin_changed = false;

    if (dns_rdataclass_fromtext(&rdclass,
              &token.value.as_textregion) ==
        ISC_R_SUCCESS)
    {
      GETTOKEN(lctx->lex, 0, &token, false);
    }

    explicit_ttl = false;
    result = dns_ttl_fromtext(&token.value.as_textregion,
            &lctx->ttl);
    if (result == ISC_R_SUCCESS) {
      limit_ttl(callbacks, source, line, &lctx->ttl);
      explicit_ttl = true;
      lctx->ttl_known = true;
      GETTOKEN(lctx->lex, 0, &token, false);
    }

    if (token.type != isc_tokentype_string) {
      UNEXPECTED_ERROR("isc_lex_gettoken() returned "
           "unexpected token type");
      result = ISC_R_UNEXPECTED;
      if (MANYERRS(lctx, result)) {
        SETRESULT(lctx, result);
        read_till_eol = true;
        continue;
      } else {
        goto insist_and_cleanup;
      }
    }

    if (rdclass == 0 &&
        dns_rdataclass_fromtext(&rdclass,
              &token.value.as_textregion) ==
          ISC_R_SUCCESS)
    {
      GETTOKEN(lctx->lex, 0, &token, false);
    }

    if (token.type != isc_tokentype_string) {
      UNEXPECTED_ERROR("isc_lex_gettoken() returned "
           "unexpected token type");
      result = ISC_R_UNEXPECTED;
      if (MANYERRS(lctx, result)) {
        SETRESULT(lctx, result);
        read_till_eol = true;
        continue;
      } else {
        goto insist_and_cleanup;
      }
    }

    result = dns_rdatatype_fromtext(&type,
            &token.value.as_textregion);
    if (result != ISC_R_SUCCESS) {
      (*callbacks->warn)(
        callbacks, "%s:%lu: unknown RR type '%.*s'",
        source, line, token.value.as_textregion.length,
        token.value.as_textregion.base);
      if (MANYERRS(lctx, result)) {
        SETRESULT(lctx, result);
        read_till_eol = true;
        continue;
      } else {
        goto insist_and_cleanup;
      }
    }

    /*
     * If the class specified does not match the zone's class
     * print out a error message and exit.
     */
    if (rdclass != 0 && rdclass != lctx->zclass) {
    bad_class:

      dns_rdataclass_format(rdclass, classname1,
                sizeof(classname1));
      dns_rdataclass_format(lctx->zclass, classname2,
                sizeof(classname2));
      (*callbacks->error)(callbacks,
              "%s:%lu: class '%s' != "
              "zone class '%s'",
              source, line, classname1,
              classname2);
      result = DNS_R_BADCLASS;
      if (MANYERRS(lctx, result)) {
        SETRESULT(lctx, result);
        read_till_eol = true;
        continue;
      } else {
        goto insist_and_cleanup;
      }
    }

    if (type == dns_rdatatype_ns && ictx->glue == NULL) {
      current_has_delegation = true;
    }

    /*
     * RFC1123: MD and MF are not allowed to be loaded from
     * master files.
     */
    if (dns_master_isprimary(lctx) &&
        (type == dns_rdatatype_md || type == dns_rdatatype_mf))
    {
      char typebuf[DNS_RDATATYPE_FORMATSIZE];

      result = DNS_R_OBSOLETE;

      dns_rdatatype_format(type, typebuf, sizeof(typebuf));
      (*callbacks->error)(callbacks, "%s:%lu: %s '%s': %s",
              source, line, "type", typebuf,
              isc_result_totext(result));
      if (MANYERRS(lctx, result)) {
        SETRESULT(lctx, result);
      } else {
        goto insist_and_cleanup;
      }
    }

    /*
     * RFC2930: TKEY and TSIG are not allowed to be loaded
     * from master files.
     */
    if (dns_master_isprimary(lctx) && dns_rdatatype_ismeta(type)) {
      char typebuf[DNS_RDATATYPE_FORMATSIZE];

      result = DNS_R_METATYPE;

      dns_rdatatype_format(type, typebuf, sizeof(typebuf));
      (*callbacks->error)(callbacks, "%s:%lu: %s '%s': %s",
              source, line, "type", typebuf,
              isc_result_totext(result));
      if (MANYERRS(lctx, result)) {
        SETRESULT(lctx, result);
      } else {
        goto insist_and_cleanup;
      }
    }

    /*
     * Find a rdata structure.
     */
    if (rdcount == rdata_size) {
      new_rdata = grow_rdata(rdata_size + RDSZ, rdata,
                 rdata_size, &current_list,
                 &glue_list, mctx);
      rdata_size += RDSZ;
      rdata = new_rdata;
    }

    /*
     * Peek at the NS record.
     */
    if (type == dns_rdatatype_ns &&
        lctx->zclass == dns_rdataclass_in &&
        (lctx->options & DNS_MASTER_CHECKNS) != 0)
    {
      GETTOKEN(lctx->lex, 0, &token, false);
      result = check_ns(lctx, &token, source, line);
      isc_lex_ungettoken(lctx->lex, &token);
      if ((lctx->options & DNS_MASTER_FATALNS) != 0) {
        if (MANYERRS(lctx, result)) {
          SETRESULT(lctx, result);
        } else if (result != ISC_R_SUCCESS) {
          goto insist_and_cleanup;
        }
      }
    }

    /*
     * Check owner name.
     */
    options &= ~DNS_RDATA_CHECKREVERSE;
    if ((lctx->options & DNS_MASTER_CHECKNAMES) != 0) {
      bool ok;
      dns_name_t *name;

      name = (ictx->glue != NULL) ? ictx->glue
                : ictx->current;
      ok = dns_rdata_checkowner(name, lctx->zclass, type,
              true);
      if (!ok) {
        char namebuf[DNS_NAME_FORMATSIZE];
        const char *desc;
        dns_name_format(name, namebuf, sizeof(namebuf));
        result = DNS_R_BADOWNERNAME;
        desc = isc_result_totext(result);
        if (CHECKNAMESFAIL(lctx->options) ||
            type == dns_rdatatype_nsec3)
        {
          (*callbacks->error)(
            callbacks, "%s:%lu: %s: %s",
            source, line, namebuf, desc);
          if (MANYERRS(lctx, result)) {
            SETRESULT(lctx, result);
          } else {
            goto cleanup;
          }
        } else {
          (*callbacks->warn)(
            callbacks, "%s:%lu: %s: %s",
            source, line, namebuf, desc);
        }
      }
      if (type == dns_rdatatype_ptr &&
          !dns_name_isdnssd(name) &&
          (dns_name_issubdomain(name, &in_addr_arpa) ||
           dns_name_issubdomain(name, &ip6_arpa) ||
           dns_name_issubdomain(name, &ip6_int)))
      {
        options |= DNS_RDATA_CHECKREVERSE;
      }
    }

    /*
     * Read rdata contents.
     */
    dns_rdata_init(&rdata[rdcount]);
    target_ft = target;
    result = dns_rdata_fromtext(&rdata[rdcount], lctx->zclass, type,
              lctx->lex, ictx->origin, options,
              lctx->mctx, &target, callbacks);
    if (MANYERRS(lctx, result)) {
      SETRESULT(lctx, result);
      continue;
    } else if (result != ISC_R_SUCCESS) {
      goto insist_and_cleanup;
    }

    if (ictx->drop) {
      target = target_ft;
      continue;
    }

    if (type == dns_rdatatype_soa &&
        (lctx->options & DNS_MASTER_ZONE) != 0 &&
        !dns_name_equal(ictx->current, lctx->top))
    {
      char namebuf[DNS_NAME_FORMATSIZE];
      dns_name_format(ictx->current, namebuf,
          sizeof(namebuf));
      (*callbacks->error)(callbacks,
              "%s:%lu: SOA "
              "record not at top of zone (%s)",
              source, line, namebuf);
      result = DNS_R_NOTZONETOP;
      if (MANYERRS(lctx, result)) {
        SETRESULT(lctx, result);
        read_till_eol = true;
        target = target_ft;
        continue;
      } else {
        goto insist_and_cleanup;
      }
    }

    if (type == dns_rdatatype_svcb &&
        (lctx->options & DNS_MASTER_ZONE) != 0 &&
        (lctx->options & DNS_MASTER_CHECKSVCB) != 0)
    {
      result = dns_rdata_checksvcb(ictx->current,
                 &rdata[rdcount]);
      if (result != ISC_R_SUCCESS) {
        (*callbacks->error)(callbacks,
                "%s:%lu: SVCB "
                "record not valid: %s",
                source, line,
                isc_result_totext(result));
        if (MANYERRS(lctx, result)) {
          SETRESULT(lctx, result);
          target = target_ft;
          continue;
        } else if (result != ISC_R_SUCCESS) {
          goto insist_and_cleanup;
        }
      }
    }

    if (dns_rdatatype_atparent(type) &&
        dns_master_isprimary(lctx) &&
        dns_name_equal(ictx->current, lctx->top))
    {
      char namebuf[DNS_NAME_FORMATSIZE];
      char typebuf[DNS_RDATATYPE_FORMATSIZE];

      dns_name_format(ictx->current, namebuf,
          sizeof(namebuf));
      dns_rdatatype_format(type, typebuf, sizeof(typebuf));
      (*callbacks->error)(
        callbacks,
        "%s:%lu: %s record at top of zone (%s)", source,
        line, typebuf, namebuf);
      result = DNS_R_ATZONETOP;
      if (MANYERRS(lctx, result)) {
        SETRESULT(lctx, result);
        target = target_ft;
        continue;
      } else {
        goto insist_and_cleanup;
      }
    }

    if (dns_rdatatype_issig(type)) {
      covers = dns_rdata_covers(&rdata[rdcount]);
    } else {
      covers = dns_rdatatype_none;
    }

    if (!lctx->ttl_known && !lctx->default_ttl_known) {
      if (type == dns_rdatatype_soa) {
        (*callbacks->warn)(callbacks,
               "%s:%lu: no TTL specified; "
               "using SOA MINTTL instead",
               source, line);
        lctx->ttl = dns_soa_getminimum(&rdata[rdcount]);
        limit_ttl(callbacks, source, line, &lctx->ttl);
        lctx->default_ttl = lctx->ttl;
        lctx->default_ttl_known = true;
      } else if ((lctx->options & DNS_MASTER_HINT) != 0) {
        /*
         * Zero TTL's are fine for hints.
         */
        lctx->ttl = 0;
        lctx->default_ttl = lctx->ttl;
        lctx->default_ttl_known = true;
      } else {
        (*callbacks->warn)(callbacks,
               "%s:%lu: no TTL specified; "
               "zone rejected",
               source, line);
        result = DNS_R_NOTTL;
        if (MANYERRS(lctx, result)) {
          SETRESULT(lctx, result);
          lctx->ttl = 0;
        } else {
          goto insist_and_cleanup;
        }
      }
    } else if (!explicit_ttl && lctx->default_ttl_known) {
      lctx->ttl = lctx->default_ttl;
    } else if (!explicit_ttl && lctx->warn_1035) {
      (*callbacks->warn)(callbacks,
             "%s:%lu: "
             "using RFC1035 TTL semantics",
             source, line);
      lctx->warn_1035 = false;
    }

    if (type == dns_rdatatype_rrsig && lctx->warn_sigexpired) {
      dns_rdata_rrsig_t sig;
      result = dns_rdata_tostruct(&rdata[rdcount], &sig,
                NULL);
      RUNTIME_CHECK(result == ISC_R_SUCCESS);
      if (isc_serial_lt(sig.timeexpire, lctx->now)) {
        (*callbacks->warn)(callbacks,
               "%s:%lu: "
               "signature has expired",
               source, line);
        lctx->warn_sigexpired = false;
      }
    }

    if ((lctx->options & DNS_MASTER_AGETTL) != 0) {
      /*
       * Adjust the TTL for $DATE. If the RR has
       * already expired, set its TTL to 0. This
       * should be okay even if the TTL stretching
       * feature is not in effect, because it will
       * just be quickly expired by the cache, and the
       * way this was written before the patch it
       * could potentially add 0 TTLs anyway.
       */
      if (lctx->ttl < ttl_offset) {
        lctx->ttl = 0;
      } else {
        lctx->ttl -= ttl_offset;
      }
    }

    /*
     * Find type in rdatalist.
     * If it does not exist create new one and prepend to list
     * as this will minimise list traversal.
     */
    if (ictx->glue != NULL) {
      this = ISC_LIST_HEAD(glue_list);
    } else {
      this = ISC_LIST_HEAD(current_list);
    }

    while (this != NULL) {
      if (this->type == type && this->covers == covers) {
        break;
      }
      this = ISC_LIST_NEXT(this, link);
    }

    if (this == NULL) {
      if (rdlcount == rdatalist_size) {
        new_rdatalist = grow_rdatalist(
          rdatalist_size + RDLSZ, rdatalist,
          rdatalist_size, &current_list,
          &glue_list, mctx);
        rdatalist = new_rdatalist;
        rdatalist_size += RDLSZ;
      }
      this = &rdatalist[rdlcount++];
      dns_rdatalist_init(this);
      this->type = type;
      this->covers = covers;
      this->rdclass = lctx->zclass;
      this->ttl = lctx->ttl;
      if (ictx->glue != NULL) {
        ISC_LIST_INITANDPREPEND(glue_list, this, link);
      } else {
        ISC_LIST_INITANDPREPEND(current_list, this,
              link);
      }
    } else if (this->ttl != lctx->ttl) {
      (*callbacks->warn)(callbacks,
             "%s:%lu: "
             "TTL set to prior TTL (%lu)",
             source, line, this->ttl);
      lctx->ttl = this->ttl;
    }

    if ((lctx->options & DNS_MASTER_CHECKTTL) != 0 &&
        lctx->ttl > lctx->maxttl)
    {
      (callbacks->error)(callbacks,
             "dns_master_load: %s:%lu: "
             "TTL %d exceeds configured "
             "max-zone-ttl %d",
             source, line, lctx->ttl,
             lctx->maxttl);
      result = ISC_R_RANGE;
      goto log_and_cleanup;
    }

    ISC_LIST_APPEND(this->rdata, &rdata[rdcount], link);
    if (ictx->glue != NULL) {
      ictx->glue_line = line;
    } else {
      ictx->current_line = line;
    }
    rdcount++;

    /*
     * We must have at least 64k as rdlen is 16 bits.
     * If we don't commit everything we have so far.
     */
    if ((target.length - target.used) < MINTSIZ) {
      COMMITALL;
    }
  next_line:;
  }

  /*
   * Commit what has not yet been committed.
   */
  result = commit(callbacks, lctx, &current_list, ictx->current, source,
      ictx->current_line);
  if (MANYERRS(lctx, result)) {
    SETRESULT(lctx, result);
  } else if (result != ISC_R_SUCCESS) {
    goto insist_and_cleanup;
  }
  result = commit(callbacks, lctx, &glue_list, ictx->glue, source,
      ictx->glue_line);
  if (MANYERRS(lctx, result)) {
    SETRESULT(lctx, result);
  } else if (result != ISC_R_SUCCESS) {
    goto insist_and_cleanup;
  } else if (lctx->result != ISC_R_SUCCESS) {
    result = lctx->result;
  } else if (lctx->seen_include) {
    result = DNS_R_SEENINCLUDE;
  }

  goto cleanup;

log_and_cleanup:
  LOGIT(result);

insist_and_cleanup:
  INSIST(result != ISC_R_SUCCESS);

cleanup:
  /* commit the database transaction */
  if (callbacks->commit != NULL) {
    callbacks->commit(callbacks->add_private);
  }

  ISC_LIST_FOREACH(current_list, this, link) {
    ISC_LIST_UNLINK(current_list, this, link);
  }
  ISC_LIST_FOREACH(glue_list, this, link) {
    ISC_LIST_UNLINK(glue_list, this, link);
  }
  if (rdatalist != NULL) {
    isc_mem_cput(mctx, rdatalist, rdatalist_size,
           sizeof(*rdatalist));
  }
  if (rdata != NULL) {
    isc_mem_cput(mctx, rdata, rdata_size, sizeof(*rdata));
  }
  if (target_mem != NULL) {
    isc_mem_put(mctx, target_mem, target_size);
  }
  if (include_file != NULL) {
    isc_mem_free(mctx, include_file);
  }
  if (range != NULL) {
    isc_mem_free(mctx, range);
  }
  if (lhs != NULL) {
    isc_mem_free(mctx, lhs);
  }
  if (gtype != NULL) {
    isc_mem_free(mctx, gtype);
  }
  if (rhs != NULL) {
    isc_mem_free(mctx, rhs);
  }

  return result;
}

static isc_result_t
pushfile(const char *master_file, dns_name_t *origin, dns_loadctx_t *lctx) {
  isc_result_t result;
  dns_incctx_t *ictx;
  dns_incctx_t *newctx = NULL;
  isc_region_t r;

  REQUIRE(master_file != NULL);
  REQUIRE(DNS_LCTX_VALID(lctx));

  ictx = lctx->inc;
  lctx->seen_include = true;

  incctx_create(lctx->mctx, origin, &newctx);

  /*
   * Push origin_changed.
   */
  newctx->origin_changed = ictx->origin_changed;

  /* Set current domain. */
  if (ictx->glue != NULL || ictx->current != NULL) {
    newctx->current_in_use = find_free_name(newctx);
    newctx->current = dns_fixedname_name(
      &newctx->fixed[newctx->current_in_use]);
    newctx->in_use[newctx->current_in_use] = true;
    dns_name_toregion(
      (ictx->glue != NULL) ? ictx->glue : ictx->current, &r);
    dns_name_fromregion(newctx->current, &r);
    newctx->drop = ictx->drop;
  }

  CHECK((lctx->openfile)(lctx, master_file));
  newctx->parent = ictx;
  lctx->inc = newctx;

  if (lctx->include_cb != NULL) {
    lctx->include_cb(master_file, lctx->include_arg);
  }
  return ISC_R_SUCCESS;

cleanup:
  incctx_destroy(lctx->mctx, newctx);
  return result;
}

/*
 * Fill/check exists buffer with 'len' bytes.  Track remaining bytes to be
 * read when incrementally filling the buffer.
 */
static isc_result_t
read_and_check(bool do_read, isc_buffer_t *buffer, size_t len, FILE *f,
         uint32_t *totallen) {
  REQUIRE(totallen != NULL);

  if (do_read) {
    INSIST(isc_buffer_availablelength(buffer) >= len);
    RETERR(isc_stdio_read(isc_buffer_used(buffer), 1, len, f,
              NULL));
    isc_buffer_add(buffer, (unsigned int)len);
    if (*totallen < len) {
      return ISC_R_RANGE;
    }
    *totallen -= (uint32_t)len;
  } else if (isc_buffer_remaininglength(buffer) < len) {
    return ISC_R_RANGE;
  }

  return ISC_R_SUCCESS;
}

static isc_result_t
load_header(dns_loadctx_t *lctx) {
  isc_result_t result = ISC_R_SUCCESS;
  dns_masterrawheader_t header;
  dns_rdatacallbacks_t *callbacks;
  size_t commonlen = sizeof(header.format) + sizeof(header.version);
  size_t remainder;
  unsigned char data[sizeof(header)];
  isc_buffer_t target;

  REQUIRE(DNS_LCTX_VALID(lctx));

  if (lctx->format != dns_masterformat_raw) {
    return ISC_R_NOTIMPLEMENTED;
  }

  callbacks = lctx->callbacks;
  dns_master_initrawheader(&header);

  INSIST(commonlen <= sizeof(header));
  isc_buffer_init(&target, data, sizeof(data));

  result = isc_stdio_read(data, 1, commonlen, lctx->f, NULL);
  if (result != ISC_R_SUCCESS) {
    UNEXPECTED_ERROR("isc_stdio_read failed: %s",
         isc_result_totext(result));
    return result;
  }

  isc_buffer_add(&target, (unsigned int)commonlen);
  header.format = isc_buffer_getuint32(&target);
  if (header.format != lctx->format) {
    (*callbacks->error)(callbacks,
            "dns_master_load: "
            "file format mismatch (not raw)");
    return ISC_R_NOTIMPLEMENTED;
  }

  header.version = isc_buffer_getuint32(&target);

  switch (header.version) {
  case 0:
    remainder = sizeof(header.dumptime);
    break;
  case DNS_RAWFORMAT_VERSION:
    remainder = sizeof(header) - commonlen;
    break;
  default:
    (*callbacks->error)(callbacks, "dns_master_load: "
                 "unsupported file format "
                 "version");
    return ISC_R_NOTIMPLEMENTED;
  }

  result = isc_stdio_read(data + commonlen, 1, remainder, lctx->f, NULL);
  if (result != ISC_R_SUCCESS) {
    UNEXPECTED_ERROR("isc_stdio_read failed: %s",
         isc_result_totext(result));
    return result;
  }

  isc_buffer_add(&target, (unsigned int)remainder);
  header.dumptime = isc_buffer_getuint32(&target);
  if (header.version == DNS_RAWFORMAT_VERSION) {
    header.flags = isc_buffer_getuint32(&target);
    header.sourceserial = isc_buffer_getuint32(&target);
    header.lastxfrin = isc_buffer_getuint32(&target);
  }

  lctx->first = false;
  lctx->header = header;

  return ISC_R_SUCCESS;
}

static isc_result_t
openfile_raw(dns_loadctx_t *lctx, const char *master_file) {
  isc_result_t result;

  result = isc_stdio_open(master_file, "rb", &lctx->f);
  if (result != ISC_R_SUCCESS && result != ISC_R_FILENOTFOUND) {
    UNEXPECTED_ERROR("isc_stdio_open() failed: %s",
         isc_result_totext(result));
  }

  return result;
}

static isc_result_t
load_raw(dns_loadctx_t *lctx) {
  isc_result_t result = ISC_R_SUCCESS;
  dns_rdatacallbacks_t *callbacks;
  unsigned char namebuf[DNS_NAME_MAXWIRE];
  dns_fixedname_t fixed;
  dns_name_t *name;
  rdatalist_head_t head, dummy;
  dns_rdatalist_t rdatalist;
  isc_mem_t *mctx = lctx->mctx;
  dns_rdata_t *rdata = NULL;
  unsigned int rdata_size = 0;
  int target_size = TSIZ;
  isc_buffer_t target, buf;
  unsigned char *target_mem = NULL;
  dns_decompress_t dctx;

  callbacks = lctx->callbacks;
  dctx = DNS_DECOMPRESS_NEVER;

  if (lctx->first) {
    RETERR(load_header(lctx));
  }

  ISC_LIST_INIT(head);
  ISC_LIST_INIT(dummy);

  /*
   * Allocate target_size of buffer space.  This is greater than twice
   * the maximum individual RR data size.
   */
  target_mem = isc_mem_get(mctx, target_size);
  isc_buffer_init(&target, target_mem, target_size);

  name = dns_fixedname_initname(&fixed);

  /* open a database transaction */
  if (callbacks->setup != NULL) {
    callbacks->setup(callbacks->add_private);
  }

  /*
   * In the following loop, we regard any error fatal regardless of
   * whether "MANYERRORS" is set in the context option.  This is because
   * normal errors should already have been checked at creation time.
   * Besides, it is very unlikely that we can recover from an error
   * in this format, and so trying to continue parsing erroneous data
   * does not really make sense.
   */
  while (true) {
    unsigned int i, rdcount;
    uint16_t namelen;
    uint32_t totallen;
    size_t minlen, readlen;
    bool sequential_read = false;

    /* Read the data length */
    isc_buffer_clear(&target);
    INSIST(isc_buffer_availablelength(&target) >= sizeof(totallen));
    result = isc_stdio_read(target.base, 1, sizeof(totallen),
          lctx->f, NULL);
    if (result == ISC_R_EOF) {
      result = ISC_R_SUCCESS;
      break;
    }
    if (result != ISC_R_SUCCESS) {
      goto cleanup;
    }
    isc_buffer_add(&target, sizeof(totallen));
    totallen = isc_buffer_getuint32(&target);

    /*
     * Validation: the input data must at least contain the common
     * header.
     */
    minlen = sizeof(totallen) + sizeof(uint16_t) +
       sizeof(uint16_t) + sizeof(uint16_t) +
       sizeof(uint32_t) + sizeof(uint32_t);
    if (totallen < minlen) {
      CLEANUP(ISC_R_RANGE);
    }
    totallen -= sizeof(totallen);

    isc_buffer_clear(&target);
    if (totallen > isc_buffer_availablelength(&target)) {
      /*
       * The default buffer size should typically be large
       * enough to store the entire RRset.  We could try to
       * allocate enough space if this is not the case, but
       * it might cause a hazardous result when "totallen"
       * is forged.  Thus, we'd rather take an inefficient
       * but robust approach in this atypical case: read
       * data step by step, and commit partial data when
       * necessary.  Note that the buffer must be large
       * enough to store the "header part", owner name, and
       * at least one rdata (however large it is).
       */
      sequential_read = true;
      readlen = minlen - sizeof(totallen);
    } else {
      /*
       * Typical case.  We can read the whole RRset at once
       * with the default buffer.
       */
      readlen = totallen;
    }
    CHECK(isc_stdio_read(target.base, 1, readlen, lctx->f, NULL));
    isc_buffer_add(&target, (unsigned int)readlen);
    totallen -= (uint32_t)readlen;

    /* Construct RRset headers */
    dns_rdatalist_init(&rdatalist);
    rdatalist.rdclass = isc_buffer_getuint16(&target);
    if (lctx->zclass != rdatalist.rdclass) {
      CLEANUP(DNS_R_BADCLASS);
    }
    rdatalist.type = isc_buffer_getuint16(&target);
    rdatalist.covers = isc_buffer_getuint16(&target);
    rdatalist.ttl = isc_buffer_getuint32(&target);
    rdcount = isc_buffer_getuint32(&target);
    if (rdcount == 0 || rdcount > 0xffff) {
      CLEANUP(ISC_R_RANGE);
    }
    INSIST(isc_buffer_consumedlength(&target) <= readlen);

    /* Owner name: length followed by name */
    CHECK(read_and_check(sequential_read, &target, sizeof(namelen),
             lctx->f, &totallen));
    namelen = isc_buffer_getuint16(&target);
    if (namelen > sizeof(namebuf)) {
      CLEANUP(ISC_R_RANGE);
    }

    CHECK(read_and_check(sequential_read, &target, namelen, lctx->f,
             &totallen));

    isc_buffer_setactive(&target, (unsigned int)namelen);
    CHECK(dns_name_fromwire(name, &target, dctx, NULL));

    if ((lctx->options & DNS_MASTER_CHECKTTL) != 0 &&
        rdatalist.ttl > lctx->maxttl)
    {
      (callbacks->error)(callbacks,
             "dns_master_load: "
             "TTL %d exceeds configured "
             "max-zone-ttl %d",
             rdatalist.ttl, lctx->maxttl);
      CLEANUP(ISC_R_RANGE);
    }

    /* Rdata contents. */
    if (rdcount > rdata_size) {
      dns_rdata_t *new_rdata = NULL;

      new_rdata = grow_rdata(rdcount + RDSZ, rdata,
                 rdata_size, &head, &dummy, mctx);
      rdata_size = rdcount + RDSZ;
      rdata = new_rdata;
    }

  continue_read:
    for (i = 0; i < rdcount; i++) {
      uint16_t rdlen;

      dns_rdata_init(&rdata[i]);

      if (sequential_read &&
          isc_buffer_availablelength(&target) < MINTSIZ)
      {
        unsigned int j;

        INSIST(i > 0); /* detect an infinite loop */

        /* Partial Commit. */
        ISC_LIST_APPEND(head, &rdatalist, link);
        result = commit(callbacks, lctx, &head, name,
            NULL, 0);
        for (j = 0; j < i; j++) {
          ISC_LIST_UNLINK(rdatalist.rdata,
              &rdata[j], link);
          dns_rdata_reset(&rdata[j]);
        }
        if (result != ISC_R_SUCCESS) {
          goto cleanup;
        }

        /* Rewind the buffer and continue */
        isc_buffer_clear(&target);

        rdcount -= i;

        goto continue_read;
      }

      /* rdata length */
      CHECK(read_and_check(sequential_read, &target,
               sizeof(rdlen), lctx->f,
               &totallen));
      rdlen = isc_buffer_getuint16(&target);

      /* rdata */
      CHECK(read_and_check(sequential_read, &target, rdlen,
               lctx->f, &totallen));
      isc_buffer_setactive(&target, (unsigned int)rdlen);
      /*
       * It is safe to have the source active region and
       * the target available region be the same if
       * decompression is disabled (see dctx above) and we
       * are not downcasing names (options == 0).
       */
      isc_buffer_init(&buf, isc_buffer_current(&target),
          (unsigned int)rdlen);
      CHECK(dns_rdata_fromwire(&rdata[i], rdatalist.rdclass,
             rdatalist.type, &target, dctx,
             &buf));
      ISC_LIST_APPEND(rdatalist.rdata, &rdata[i], link);
    }

    /*
     * Sanity check.  Still having remaining space is not
     * necessarily critical, but it very likely indicates broken
     * or malformed data.
     */
    if (isc_buffer_remaininglength(&target) != 0 || totallen != 0) {
      CLEANUP(ISC_R_RANGE);
    }

    ISC_LIST_APPEND(head, &rdatalist, link);

    /* Commit this RRset.  rdatalist will be unlinked. */
    result = commit(callbacks, lctx, &head, name, NULL, 0);

    for (i = 0; i < rdcount; i++) {
      ISC_LIST_UNLINK(rdatalist.rdata, &rdata[i], link);
      dns_rdata_reset(&rdata[i]);
    }

    if (result != ISC_R_SUCCESS) {
      goto cleanup;
    }
  }

  if (result == ISC_R_SUCCESS && lctx->result != ISC_R_SUCCESS) {
    result = lctx->result;
  }

  if (result == ISC_R_SUCCESS && callbacks->rawdata != NULL) {
    (*callbacks->rawdata)(callbacks->zone, &lctx->header);
  }

cleanup:
  /* commit the database transaction */
  if (callbacks->commit != NULL) {
    callbacks->commit(callbacks->add_private);
  }

  if (rdata != NULL) {
    isc_mem_cput(mctx, rdata, rdata_size, sizeof(*rdata));
  }
  if (target_mem != NULL) {
    isc_mem_put(mctx, target_mem, target_size);
  }
  if (result != ISC_R_SUCCESS) {
    (*callbacks->error)(callbacks, "dns_master_load: %s",
            isc_result_totext(result));
  }

  return result;
}

isc_result_t
dns_master_loadfile(const char *master_file, dns_name_t *top,
        dns_name_t *origin, dns_rdataclass_t zclass,
        unsigned int options, uint32_t resign,
        dns_rdatacallbacks_t *callbacks,
        dns_masterincludecb_t include_cb, void *include_arg,
        isc_mem_t *mctx, dns_masterformat_t format,
        dns_ttl_t maxttl) {
  dns_loadctx_t *lctx = NULL;
  isc_result_t result;

  loadctx_create(format, mctx, options, resign, top, zclass, origin,
           callbacks, NULL, NULL, include_cb, include_arg, NULL,
           &lctx);

  lctx->maxttl = maxttl;

  CHECK((lctx->openfile)(lctx, master_file));

  result = (lctx->load)(lctx);
  INSIST(result != DNS_R_CONTINUE);

cleanup:
  dns_loadctx_detach(&lctx);
  return result;
}

/*
 * The combination of isc_work_enqueue() on the current loop and callback on
 * lctx->loop ensures the correct ordering:
 *
 * 1. dns_master_loadfileasync() calls isc_work_enqueue() on the current loop.
 * 2. master_load() runs asynchronously and can finish before the entry point
 *    returns; master_load_done() is queued on the current loop and cannot run
 *    until the entry point returns.
 * 3. The entry point publishes *lctxp.
 * 4. master_load_done() runs on the current loop and hands off to lctx->loop.
 * 5. lctx->done() runs on lctx->loop asynchronously.
 */
static void
master_load(void *arg) {
  dns_loadctx_t *lctx = arg;
  lctx->result = (lctx->load)(lctx);
}

static void
master_load_callback(void *arg) {
  dns_loadctx_t *lctx = arg;

  (lctx->done)(lctx->done_arg, lctx->result);
  isc_loop_detach(&lctx->loop);
  dns_loadctx_detach(&lctx);
}

static void
master_load_done(void *arg) {
  dns_loadctx_t *lctx = arg;

  isc_async_run(lctx->loop, master_load_callback, lctx);
}

isc_result_t
dns_master_loadfileasync(const char *master_file, dns_name_t *top,
       dns_name_t *origin, dns_rdataclass_t zclass,
       unsigned int options, uint32_t resign,
       dns_rdatacallbacks_t *callbacks, isc_loop_t *loop,
       dns_loaddonefunc_t done, void *done_arg,
       dns_loadctx_t **lctxp,
       dns_masterincludecb_t include_cb, void *include_arg,
       isc_mem_t *mctx, dns_masterformat_t format,
       uint32_t maxttl) {
  dns_loadctx_t *lctx = NULL;
  isc_result_t result;

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

  loadctx_create(format, mctx, options, resign, top, zclass, origin,
           callbacks, done, done_arg, include_cb, include_arg, NULL,
           &lctx);

  lctx->maxttl = maxttl;

  result = (lctx->openfile)(lctx, master_file);
  if (result != ISC_R_SUCCESS) {
    dns_loadctx_detach(&lctx);
    return result;
  }

  dns_loadctx_ref(lctx);
  isc_loop_attach(loop, &lctx->loop);
  isc_work_enqueue(isc_loop(), master_load, master_load_done, lctx);

  *lctxp = lctx;

  return ISC_R_SUCCESS;
}

isc_result_t
dns_master_loadstream(FILE *stream, dns_name_t *top, dns_name_t *origin,
          dns_rdataclass_t zclass, unsigned int options,
          dns_rdatacallbacks_t *callbacks, isc_mem_t *mctx) {
  isc_result_t result;
  dns_loadctx_t *lctx = NULL;

  REQUIRE(stream != NULL);

  loadctx_create(dns_masterformat_text, mctx, options, 0, top, zclass,
           origin, callbacks, NULL, NULL, NULL, NULL, NULL, &lctx);

  isc_lex_openstream(lctx->lex, stream);

  result = (lctx->load)(lctx);
  INSIST(result != DNS_R_CONTINUE);

  dns_loadctx_detach(&lctx);
  return result;
}

isc_result_t
dns_master_loadbuffer(isc_buffer_t *buffer, dns_name_t *top, dns_name_t *origin,
          dns_rdataclass_t zclass, unsigned int options,
          dns_rdatacallbacks_t *callbacks, isc_mem_t *mctx) {
  isc_result_t result;
  dns_loadctx_t *lctx = NULL;

  REQUIRE(buffer != NULL);

  loadctx_create(dns_masterformat_text, mctx, options, 0, top, zclass,
           origin, callbacks, NULL, NULL, NULL, NULL, NULL, &lctx);

  CHECK(isc_lex_openbuffer(lctx->lex, buffer));

  result = (lctx->load)(lctx);
  INSIST(result != DNS_R_CONTINUE);

cleanup:
  dns_loadctx_detach(&lctx);
  return result;
}

/*
 * Grow the slab of dns_rdatalist_t structures.
 * Re-link glue and current list.
 */
static dns_rdatalist_t *
grow_rdatalist(int new_len, dns_rdatalist_t *oldlist, int old_len,
         rdatalist_head_t *current, rdatalist_head_t *glue,
         isc_mem_t *mctx) {
  dns_rdatalist_t *newlist;
  int rdlcount = 0;
  ISC_LIST(dns_rdatalist_t) save;

  newlist = isc_mem_cget(mctx, new_len, sizeof(newlist[0]));

  ISC_LIST_INIT(save);
  ISC_LIST_FOREACH(*current, this, link) {
    ISC_LIST_UNLINK(*current, this, link);
    ISC_LIST_APPEND(save, this, link);
  }
  ISC_LIST_FOREACH(save, this, link) {
    ISC_LIST_UNLINK(save, this, link);
    INSIST(rdlcount < new_len);
    newlist[rdlcount] = *this;
    ISC_LIST_APPEND(*current, &newlist[rdlcount], link);
    rdlcount++;
  }

  ISC_LIST_INIT(save);
  ISC_LIST_FOREACH(*glue, this, link) {
    ISC_LIST_UNLINK(*glue, this, link);
    ISC_LIST_APPEND(save, this, link);
  }
  ISC_LIST_FOREACH(save, this, link) {
    ISC_LIST_UNLINK(save, this, link);
    INSIST(rdlcount < new_len);
    newlist[rdlcount] = *this;
    ISC_LIST_APPEND(*glue, &newlist[rdlcount], link);
    rdlcount++;
  }

  INSIST(rdlcount == old_len);
  if (oldlist != NULL) {
    isc_mem_cput(mctx, oldlist, old_len, sizeof(*oldlist));
  }
  return newlist;
}

/*
 * Grow the slab of rdata structs.
 * Re-link the current and glue chains.
 */
static dns_rdata_t *
grow_rdata(int new_len, dns_rdata_t *oldlist, int old_len,
     rdatalist_head_t *current, rdatalist_head_t *glue, isc_mem_t *mctx) {
  dns_rdata_t *newlist;
  int rdcount = 0;
  ISC_LIST(dns_rdata_t) save;

  newlist = isc_mem_cget(mctx, new_len, sizeof(*newlist));

  /*
   * Copy current relinking.
   */
  ISC_LIST_FOREACH(*current, this, link) {
    ISC_LIST_INIT(save);
    ISC_LIST_FOREACH(this->rdata, rdata, link) {
      ISC_LIST_UNLINK(this->rdata, rdata, link);
      ISC_LIST_APPEND(save, rdata, link);
    }
    ISC_LIST_FOREACH(save, rdata, link) {
      ISC_LIST_UNLINK(save, rdata, link);
      INSIST(rdcount < new_len);
      newlist[rdcount] = *rdata;
      ISC_LIST_APPEND(this->rdata, &newlist[rdcount], link);
      rdcount++;
    }
  }

  /*
   * Copy glue relinking.
   */
  ISC_LIST_FOREACH(*glue, this, link) {
    ISC_LIST_INIT(save);
    ISC_LIST_FOREACH(this->rdata, rdata, link) {
      ISC_LIST_UNLINK(this->rdata, rdata, link);
      ISC_LIST_APPEND(save, rdata, link);
    }
    ISC_LIST_FOREACH(save, rdata, link) {
      ISC_LIST_UNLINK(save, rdata, link);
      INSIST(rdcount < new_len);
      newlist[rdcount] = *rdata;
      ISC_LIST_APPEND(this->rdata, &newlist[rdcount], link);
      rdcount++;
    }
  }
  INSIST(rdcount == old_len || rdcount == 0);
  if (oldlist != NULL) {
    isc_mem_cput(mctx, oldlist, old_len, sizeof(*oldlist));
  }
  return newlist;
}

static uint32_t
resign_fromlist(dns_rdatalist_t *this, dns_loadctx_t *lctx) {
  dns_rdata_t *rdata;
  dns_rdata_rrsig_t sig;
  uint32_t when;

  rdata = ISC_LIST_HEAD(this->rdata);
  INSIST(rdata != NULL);
  (void)dns_rdata_tostruct(rdata, &sig, NULL);
  if (isc_serial_gt(sig.timesigned, lctx->now)) {
    when = lctx->now;
  } else {
    when = sig.timeexpire - lctx->resign;
  }

  rdata = ISC_LIST_NEXT(rdata, link);
  while (rdata != NULL) {
    (void)dns_rdata_tostruct(rdata, &sig, NULL);
    if (isc_serial_gt(sig.timesigned, lctx->now)) {
      when = lctx->now;
    } else if (sig.timeexpire - lctx->resign < when) {
      when = sig.timeexpire - lctx->resign;
    }
    rdata = ISC_LIST_NEXT(rdata, link);
  }
  return when;
}

/*
 * Convert each element from a rdatalist_t to rdataset then call commit.
 * Unlink each element as we go.
 */

static isc_result_t
commit(dns_rdatacallbacks_t *callbacks, dns_loadctx_t *lctx,
       rdatalist_head_t *head, dns_name_t *owner, const char *source,
       unsigned int line) {
  dns_rdataset_t dataset;
  isc_result_t result = ISC_R_SUCCESS;
  char namebuf[DNS_NAME_FORMATSIZE];
  void (*error)(struct dns_rdatacallbacks *, const char *, ...);

  error = callbacks->error;

  ISC_LIST_FOREACH(*head, this, link) {
    dns_rdataset_init(&dataset);
    dns_rdatalist_tordataset(this, &dataset);
    dataset.trust = dns_trust_ultimate;
    /*
     * If this is a secure dynamic zone set the re-signing time.
     */
    if (dataset.type == dns_rdatatype_rrsig &&
        (lctx->options & DNS_MASTER_RESIGN) != 0)
    {
      dataset.attributes.resign = true;
      dataset.resign = resign_fromlist(this, lctx);
    }
    result = callbacks->update(callbacks->add_private, owner,
             &dataset,
             DNS_DIFFOP_ADD DNS__DB_FILELINE);
    if (result != ISC_R_SUCCESS) {
      dns_name_format(owner, namebuf, sizeof(namebuf));
      if (source != NULL) {
        (*error)(callbacks, "%s: %s:%lu: %s: %s",
           "dns_master_load", source, line,
           namebuf, isc_result_totext(result));
      } else {
        (*error)(callbacks, "%s: %s: %s",
           "dns_master_load", namebuf,
           isc_result_totext(result));
      }
    }
    if (MANYERRS(lctx, result)) {
      SETRESULT(lctx, result);
    } else if (result != ISC_R_SUCCESS) {
      break;
    }
    ISC_LIST_UNLINK(*head, this, link);
  }

  return result;
}

/*
 * Returns true if one of the NS rdata's contains 'owner'.
 */

static bool
is_glue(rdatalist_head_t *head, dns_name_t *owner) {
  dns_rdatalist_t *nslist = NULL;
  isc_region_t region;
  dns_name_t name;

  /*
   * Find NS rrset.
   */
  ISC_LIST_FOREACH(*head, this, link) {
    if (this->type == dns_rdatatype_ns) {
      nslist = this;
      break;
    }
  }
  if (nslist == NULL) {
    return false;
  }

  ISC_LIST_FOREACH(nslist->rdata, rdata, link) {
    dns_name_init(&name);
    dns_rdata_toregion(rdata, &region);
    dns_name_fromregion(&name, &region);
    if (dns_name_equal(&name, owner)) {
      return true;
    }
  }
  return false;
}

void
dns_loadctx_cancel(dns_loadctx_t *lctx) {
  REQUIRE(DNS_LCTX_VALID(lctx));

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

void
dns_master_initrawheader(dns_masterrawheader_t *header) {
  memset(header, 0, sizeof(dns_masterrawheader_t));
}

Coverage Report

Created: 2026-06-15 06:56