xref: /freebsd/lib/libutil/expand_number.c (revision 55141f2c8991b2a6adbf30bb0fe3e6cbc303f06d)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
3  *
4  * Copyright (c) 2007 Eric Anderson <anderson@FreeBSD.org>
5  * Copyright (c) 2007 Pawel Jakub Dawidek <pjd@FreeBSD.org>
6  * All rights reserved.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  */
29 
30 #include <sys/cdefs.h>
31 #include <sys/types.h>
32 #include <ctype.h>
33 #include <errno.h>
34 #include <inttypes.h>
35 #include <libutil.h>
36 #include <stdint.h>
37 
38 int
39 expand_number(const char *buf, uint64_t *num)
40 {
41 	char *endptr;
42 	uintmax_t umaxval;
43 	uint64_t number;
44 	unsigned shift;
45 	int serrno;
46 
47 	serrno = errno;
48 	errno = 0;
49 	umaxval = strtoumax(buf, &endptr, 0);
50 	if (umaxval > UINT64_MAX)
51 		errno = ERANGE;
52 	if (errno != 0)
53 		return (-1);
54 	errno = serrno;
55 	number = umaxval;
56 
57 	switch (tolower((unsigned char)*endptr)) {
58 	case 'e':
59 		shift = 60;
60 		break;
61 	case 'p':
62 		shift = 50;
63 		break;
64 	case 't':
65 		shift = 40;
66 		break;
67 	case 'g':
68 		shift = 30;
69 		break;
70 	case 'm':
71 		shift = 20;
72 		break;
73 	case 'k':
74 		shift = 10;
75 		break;
76 	case 'b':
77 		shift = 0;
78 		break;
79 	case '\0': /* No unit. */
80 		*num = number;
81 		return (0);
82 	default:
83 		/* Unrecognized unit. */
84 		errno = EINVAL;
85 		return (-1);
86 	}
87 
88 	/*
89 	 * Treat 'b' as an ignored suffix for all unit except 'b',
90 	 * otherwise there should be no remaining character(s).
91 	 */
92 	endptr++;
93 	if (shift != 0 && tolower((unsigned char)*endptr) == 'b')
94 		endptr++;
95 	if (*endptr != '\0') {
96 		errno = EINVAL;
97 		return (-1);
98 	}
99 
100 	if ((number << shift) >> shift != number) {
101 		/* Overflow */
102 		errno = ERANGE;
103 		return (-1);
104 	}
105 	*num = number << shift;
106 	return (0);
107 }
108