b6fbd4d50d
a very bad one, since the shift does not actually overflow. This is a better example (assuming uint64_t = unsigned long long): ~0LLU >> 9 = 0x7fffffffffffffLLU ~0LLU >> 9 << 10 = 0xfffffffffffffc00LLU ~0LLU >> 9 << 10 >> 10 = 0x3fffffffffffffLLU
101 lines
3.0 KiB
C
101 lines
3.0 KiB
C
/*-
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* Copyright (c) 2007 Eric Anderson <anderson@FreeBSD.org>
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* Copyright (c) 2007 Pawel Jakub Dawidek <pjd@FreeBSD.org>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/types.h>
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#include <ctype.h>
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#include <errno.h>
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#include <inttypes.h>
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#include <libutil.h>
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#include <stdint.h>
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/*
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* Convert an expression of the following forms to a int64_t.
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* 1) A positive decimal number.
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* 2) A positive decimal number followed by a 'b' or 'B' (mult by 1).
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* 3) A positive decimal number followed by a 'k' or 'K' (mult by 1 << 10).
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* 4) A positive decimal number followed by a 'm' or 'M' (mult by 1 << 20).
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* 5) A positive decimal number followed by a 'g' or 'G' (mult by 1 << 30).
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* 6) A positive decimal number followed by a 't' or 'T' (mult by 1 << 40).
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* 7) A positive decimal number followed by a 'p' or 'P' (mult by 1 << 50).
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* 8) A positive decimal number followed by a 'e' or 'E' (mult by 1 << 60).
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*/
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int
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expand_number(const char *buf, uint64_t *num)
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{
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uint64_t number;
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char *endptr;
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number = strtoumax(buf, &endptr, 0);
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if (endptr == buf) {
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/* No valid digits. */
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errno = EINVAL;
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return (-1);
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}
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if (*endptr == '\0') {
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/* No unit. */
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*num = number;
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return (0);
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}
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#define SHIFT(n, b) \
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do { if (((n << b) >> b) != n) goto overflow; n <<= b; } while (0)
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switch (tolower((unsigned char)*endptr)) {
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case 'e':
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SHIFT(number, 10);
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case 'p':
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SHIFT(number, 10);
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case 't':
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SHIFT(number, 10);
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case 'g':
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SHIFT(number, 10);
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case 'm':
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SHIFT(number, 10);
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case 'k':
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SHIFT(number, 10);
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case 'b':
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break;
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default:
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/* Unrecognized unit. */
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errno = EINVAL;
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return (-1);
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}
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*num = number;
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return (0);
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overflow:
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/* Overflow */
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errno = ERANGE;
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return (-1);
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}
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