diff options
Diffstat (limited to 'lib/util/strtonum.c')
| -rw-r--r-- | lib/util/strtonum.c | 193 |
1 files changed, 193 insertions, 0 deletions
diff --git a/lib/util/strtonum.c b/lib/util/strtonum.c new file mode 100644 index 0000000..12edbbe --- /dev/null +++ b/lib/util/strtonum.c @@ -0,0 +1,193 @@ +/* + * 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. + */ + +/* + * This is an open source non-commercial project. Dear PVS-Studio, please check it. + * PVS-Studio Static Code Analyzer for C, C++ and C#: http://www.viva64.com + */ + +#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; + unsigned char ch; + int remainder; + char sign; + + if (minval > maxval) { + errval = STN_INVALID; + goto done; + } + + /* Trim leading space and check sign, if any. */ + do { + ch = *cp++; + } while (isspace(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 = -(minval % 10); + if (remainder < 0) { + lastval += 1; + remainder += 10; + } + for (;; ch = *cp++) { + if (!isdigit(ch)) + break; + ch -= '0'; + if (result < lastval || (result == lastval && ch > remainder)) { + /* Skip remaining digits. */ + do { + ch = *cp++; + } while (isdigit(ch)); + errval = STN_TOOSMALL; + break; + } else { + result *= 10; + result -= ch; + errval = STN_VALID; + } + } + if (result > maxval) + errval = STN_TOOBIG; + } else { + lastval = maxval / 10; + remainder = maxval % 10; + for (;; ch = *cp++) { + if (!isdigit(ch)) + break; + ch -= '0'; + if (result > lastval || (result == lastval && ch > remainder)) { + /* Skip remaining digits. */ + do { + ch = *cp++; + } while (isdigit(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; +} |