getbsize.c revision 330897 
1/*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1991, 1993
5 *	The Regents of the University of California.  All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 * 4. Neither the name of the University nor the names of its contributors
16 *    may be used to endorse or promote products derived from this software
17 *    without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32#if defined(LIBC_SCCS) && !defined(lint)
33static char sccsid[] = "@(#)getbsize.c	8.1 (Berkeley) 6/4/93";
34#endif /* LIBC_SCCS and not lint */
35#include <sys/cdefs.h>
36__FBSDID("$FreeBSD: stable/11/lib/libc/gen/getbsize.c 330897 2018-03-14 03:19:51Z eadler $");
37
38#include <err.h>
39#include <stdio.h>
40#include <stdlib.h>
41#include <string.h>
42
43char *
44getbsize(int *headerlenp, long *blocksizep)
45{
46	static char header[20];
47	long n, max, mul, blocksize;
48	char *ep, *p;
49	const char *form;
50
51#define	KB	(1024L)
52#define	MB	(1024L * 1024L)
53#define	GB	(1024L * 1024L * 1024L)
54#define	MAXB	GB		/* No tera, peta, nor exa. */
55	form = "";
56	if ((p = getenv("BLOCKSIZE")) != NULL && *p != '\0') {
57		if ((n = strtol(p, &ep, 10)) < 0)
58			goto underflow;
59		if (n == 0)
60			n = 1;
61		if (*ep && ep[1])
62			goto fmterr;
63		switch (*ep) {
64		case 'G': case 'g':
65			form = "G";
66			max = MAXB / GB;
67			mul = GB;
68			break;
69		case 'K': case 'k':
70			form = "K";
71			max = MAXB / KB;
72			mul = KB;
73			break;
74		case 'M': case 'm':
75			form = "M";
76			max = MAXB / MB;
77			mul = MB;
78			break;
79		case '\0':
80			max = MAXB;
81			mul = 1;
82			break;
83		default:
84fmterr:			warnx("%s: unknown blocksize", p);
85			n = 512;
86			max = MAXB;
87			mul = 1;
88			break;
89		}
90		if (n > max) {
91			warnx("maximum blocksize is %ldG", MAXB / GB);
92			n = max;
93		}
94		if ((blocksize = n * mul) < 512) {
95underflow:		warnx("minimum blocksize is 512");
96			form = "";
97			blocksize = n = 512;
98		}
99	} else
100		blocksize = n = 512;
101
102	(void)snprintf(header, sizeof(header), "%ld%s-blocks", n, form);
103	*headerlenp = strlen(header);
104	*blocksizep = blocksize;
105	return (header);
106}
107