/*

 * SPDX-License-Identifier: ISC

 *

 * Copyright (c) 2013-2015, 2019-2020 Todd C. Miller <Todd.Miller@sudo.ws>

 *

 * Permission to use, copy, modify, and distribute this software for any

 * purpose with or without fee is hereby granted, provided that the above

 * copyright notice and this permission notice appear in all copies.

 *

 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES

 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF

 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR

 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES

 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN

 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF

 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

 */

#include <config.h>

#include <ctype.h>

#include <errno.h>

#include <sudo_compat.h>

#include <sudo_gettext.h>

#include <sudo_util.h>

enum strtonum_err {

    STN_INITIAL,

    STN_VALID,

    STN_INVALID,

    STN_TOOSMALL,

    STN_TOOBIG

};

/*

 * Convert a string to a number in the range [minval, maxval]

 * Unlike strtonum(), this returns the first non-digit in endp (if not NULL).

 */

long long

sudo_strtonumx(const char *str, long long minval, long long maxval, char **endp,

    const char **errstrp)

{

    enum strtonum_err errval = STN_INITIAL;

    long long lastval, result = 0;

    const char *cp = str;

    int remainder;

    char ch, sign;

    if (minval > maxval) {

  errval = STN_INVALID;

  goto done;

    }

    /* Trim leading space and check sign, if any. */

    do {

  ch = *cp++;

    } while (isspace((unsigned char)ch));

    switch (ch) {

    case '-':

  sign = '-';

  ch = *cp++;

  break;

    case '+':

  ch = *cp++;

  FALLTHROUGH;

    default:

  sign = '+';

  break;

    }

    /*

     * To prevent overflow we determine the highest (or lowest in

     * the case of negative numbers) value result can have *before*

     * if its multiplied (divided) by 10 as well as the remainder.

     * If result matches this value and the next digit is larger than

     * the remainder, we know the result is out of range.

     * The remainder is always positive since it is compared against

     * an unsigned digit.

     */

    if (sign == '-') {

  lastval = minval / 10;

  remainder = -(int)(minval % 10);

  if (remainder < 0) {

      lastval += 1;

      remainder += 10;

  }

  for (;; ch = *cp++) {

      if (!isdigit((unsigned char)ch))

    break;

      ch -= '0';

      if (result < lastval || (result == lastval && ch > remainder)) {

    /* Skip remaining digits. */

    do {

        ch = *cp++;

    } while (isdigit((unsigned char)ch));

    errval = STN_TOOSMALL;

    break;

      } else {

    result *= 10;

    result -= ch;

    errval = STN_VALID;

      }

  }

  if (result > maxval)

      errval = STN_TOOBIG;

    } else {

  lastval = maxval / 10;

  remainder = (int)(maxval % 10);

  for (;; ch = *cp++) {

      if (!isdigit((unsigned char)ch))

    break;

      ch -= '0';

      if (result > lastval || (result == lastval && ch > remainder)) {

    /* Skip remaining digits. */

    do {

        ch = *cp++;

    } while (isdigit((unsigned char)ch));

    errval = STN_TOOBIG;

    break;

      } else {

    result *= 10;

    result += ch;

    errval = STN_VALID;

      }

  }

  if (result < minval)

      errval = STN_TOOSMALL;

    }

done:

    switch (errval) {

    case STN_INITIAL:

    case STN_VALID:

  if (errstrp != NULL)

      *errstrp = NULL;

  break;

    case STN_INVALID:

  result = 0;

  errno = EINVAL;

  if (errstrp != NULL)

      *errstrp = N_("invalid value");

  break;

    case STN_TOOSMALL:

  result = 0;

  errno = ERANGE;

  if (errstrp != NULL)

      *errstrp = N_("value too small");

  break;

    case STN_TOOBIG:

  result = 0;

  errno = ERANGE;

  if (errstrp != NULL)

      *errstrp = N_("value too large");

  break;

    }

    if (endp != NULL) {

  if (errval == STN_INITIAL || errval == STN_INVALID)

      *endp = (char *)str;

  else

      *endp = (char *)(cp - 1);

    }

    return result;

}

/*

 * Convert a string to a number in the range [minval, maxval]

 */

long long

sudo_strtonum(const char *str, long long minval, long long maxval,

    const char **errstrp)

{

    const char *errstr;

    char *ep;

    long long ret;

    ret = sudo_strtonumx(str, minval, maxval, &ep, &errstr);

    /* Check for empty string and terminating NUL. */

    if (str == ep || *ep != '\0') {

  errno = EINVAL;

  errstr = N_("invalid value");

  ret = 0;

    }

    if (errstrp != NULL)

  *errstrp = errstr;

    return ret;

}