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 * 3. 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#include <err.h>
33#include <stdio.h>
34#include <stdlib.h>
35#include <string.h>
36
37char *
38getbsize(int *headerlenp, long *blocksizep)
39{
40	static char header[20];
41	long n, max, mul, blocksize;
42	char *ep, *p;
43	const char *form;
44
45#define	KB	(1024L)
46#define	MB	(1024L * 1024L)
47#define	GB	(1024L * 1024L * 1024L)
48#define	MAXB	GB		/* No tera, peta, nor exa. */
49	form = "";
50	if ((p = getenv("BLOCKSIZE")) != NULL && *p != '\0') {
51		if ((n = strtol(p, &ep, 10)) < 0)
52			goto underflow;
53		if (n == 0)
54			n = 1;
55		if (*ep && ep[1])
56			goto fmterr;
57		switch (*ep) {
58		case 'G': case 'g':
59			form = "G";
60			max = MAXB / GB;
61			mul = GB;
62			break;
63		case 'K': case 'k':
64			form = "K";
65			max = MAXB / KB;
66			mul = KB;
67			break;
68		case 'M': case 'm':
69			form = "M";
70			max = MAXB / MB;
71			mul = MB;
72			break;
73		case '\0':
74			max = MAXB;
75			mul = 1;
76			break;
77		default:
78fmterr:			warnx("%s: unknown blocksize", p);
79			n = 512;
80			max = MAXB;
81			mul = 1;
82			break;
83		}
84		if (n > max) {
85			warnx("maximum blocksize is %ldG", MAXB / GB);
86			n = max;
87		}
88		if ((blocksize = n * mul) < 512) {
89underflow:		warnx("minimum blocksize is 512");
90			form = "";
91			blocksize = n = 512;
92		}
93	} else
94		blocksize = n = 512;
95
96	(void)snprintf(header, sizeof(header), "%ld%s-blocks", n, form);
97	*headerlenp = strlen(header);
98	*blocksizep = blocksize;
99	return (header);
100}
101