/*

 * 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 <ctype.h>

#include <errno.h>

#include <inttypes.h>

#include <stdbool.h>

#include <stdio.h>

#include <stdlib.h>

#include <isc/ascii.h>

#include <isc/buffer.h>

#include <isc/parseint.h>

#include <isc/region.h>

#include <isc/result.h>

#include <isc/string.h>

#include <isc/util.h>

#include <dns/ttl.h>

static isc_result_t

bind_ttl(isc_textregion_t *source, uint32_t *ttl);

/*

 * Helper for dns_ttl_totext().

 */

static isc_result_t

ttlfmt(unsigned int t, const char *s, bool verbose, bool space,

       isc_buffer_t *target) {

  char tmp[60];

  unsigned int len;

  isc_region_t region;

  if (verbose) {

    len = snprintf(tmp, sizeof(tmp), "%s%u %s%s", space ? " " : "",

             t, s, t == 1 ? "" : "s");

  } else {

    len = snprintf(tmp, sizeof(tmp), "%u%c", t, s[0]);

  }

  INSIST(len + 1 <= sizeof(tmp));

  isc_buffer_availableregion(target, &region);

  if (len > region.length) {

    return ISC_R_NOSPACE;

  }

  memmove(region.base, tmp, len);

  isc_buffer_add(target, len);

  return ISC_R_SUCCESS;

}

/*

 * Derived from bind8 ns_format_ttl().

 */

isc_result_t

dns_ttl_totext(uint32_t src, bool verbose, bool upcase, isc_buffer_t *target) {

  unsigned int secs, mins, hours, days, weeks, x;

  secs = src % 60;

  src /= 60;

  mins = src % 60;

  src /= 60;

  hours = src % 24;

  src /= 24;

  days = src % 7;

  src /= 7;

  weeks = src;

  src = 0;

  POST(src);

  x = 0;

  if (weeks != 0) {

    RETERR(ttlfmt(weeks, "week", verbose, x > 0, target));

    x++;

  }

  if (days != 0) {

    RETERR(ttlfmt(days, "day", verbose, x > 0, target));

    x++;

  }

  if (hours != 0) {

    RETERR(ttlfmt(hours, "hour", verbose, x > 0, target));

    x++;

  }

  if (mins != 0) {

    RETERR(ttlfmt(mins, "minute", verbose, x > 0, target));

    x++;

  }

  if (secs != 0 || (weeks == 0 && days == 0 && hours == 0 && mins == 0)) {

    RETERR(ttlfmt(secs, "second", verbose, x > 0, target));

    x++;

  }

  INSIST(x > 0);

  /*

   * If only a single unit letter is printed, print it

   * in upper case. (Why?  Because BIND 8 does that.

   * Presumably it has a reason.)

   */

  if (x == 1 && upcase && !verbose) {

    isc_region_t region;

    /*

     * The unit letter is the last character in the

     * used region of the buffer.

     */

    isc_buffer_usedregion(target, &region);

    region.base[region.length - 1] =

      isc_ascii_toupper(region.base[region.length - 1]);

  }

  return ISC_R_SUCCESS;

}

isc_result_t

dns_counter_fromtext(isc_textregion_t *source, uint32_t *ttl) {

  return bind_ttl(source, ttl);

}

isc_result_t

dns_ttl_fromtext(isc_textregion_t *source, uint32_t *ttl) {

  isc_result_t result;

  result = bind_ttl(source, ttl);

  if (result != ISC_R_SUCCESS && result != ISC_R_RANGE) {

    result = DNS_R_BADTTL;

  }

  return result;

}

static isc_result_t

bind_ttl(isc_textregion_t *source, uint32_t *ttl) {

  uint64_t tmp = 0ULL;

  uint32_t n;

  char *s;

  char buf[64];

  char nbuf[64]; /* Number buffer */

  /*

   * Copy the buffer as it may not be NULL terminated.

   * No legal counter / ttl is longer that 63 characters.

   */

  if (source->length > sizeof(buf) - 1) {

    return DNS_R_SYNTAX;

  }

  /* Copy source->length bytes and NUL terminate. */

  snprintf(buf, sizeof(buf), "%.*s", (int)source->length, source->base);

  s = buf;

  do {

    isc_result_t result;

    char *np = nbuf;

    while (*s != '\0' && isdigit((unsigned char)*s)) {

      *np++ = *s++;

    }

    *np++ = '\0';

    INSIST(np - nbuf <= (int)sizeof(nbuf));

    result = isc_parse_uint32(&n, nbuf, 10);

    if (result != ISC_R_SUCCESS) {

      return DNS_R_SYNTAX;

    }

    switch (*s) {

    case 'w':

    case 'W':

      tmp += (uint64_t)n * 7 * 24 * 3600;

      s++;

      break;

    case 'd':

    case 'D':

      tmp += (uint64_t)n * 24 * 3600;

      s++;

      break;

    case 'h':

    case 'H':

      tmp += (uint64_t)n * 3600;

      s++;

      break;

    case 'm':

    case 'M':

      tmp += (uint64_t)n * 60;

      s++;

      break;

    case 's':

    case 'S':

      tmp += (uint64_t)n;

      s++;

      break;

    case '\0':

      /* Plain number? */

      if (tmp != 0ULL) {

        return DNS_R_SYNTAX;

      }

      tmp = n;

      break;

    default:

      return DNS_R_SYNTAX;

    }

  } while (*s != '\0');

  if (tmp > 0xffffffffULL) {

    return ISC_R_RANGE;

  }

  *ttl = (uint32_t)(tmp & 0xffffffffUL);

  return ISC_R_SUCCESS;

}