getbsize.c revision 7bb5660647d0106f96b000c25f5690a45734c38c 
1/*	$NetBSD: getbsize.c,v 1.17 2012/06/25 22:32:43 abs Exp $	*/
2
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 <sys/cdefs.h>
33#if defined(LIBC_SCCS) && !defined(lint)
34#if 0
35static char sccsid[] = "@(#)getbsize.c	8.1 (Berkeley) 6/4/93";
36#else
37__RCSID("$NetBSD: getbsize.c,v 1.17 2012/06/25 22:32:43 abs Exp $");
38#endif
39#endif /* not lint */
40
41#include "namespace.h"
42
43#include <assert.h>
44#include <err.h>
45#include <stdio.h>
46#include <stdlib.h>
47#include <string.h>
48
49#ifdef __weak_alias
50__weak_alias(getbsize,_getbsize)
51#endif
52
53char *
54getbsize(int *headerlenp, long *blocksizep)
55{
56	static char header[20];
57	long n, max, mul, blocksize;
58	char *ep, *p;
59	const char *form;
60
61#define	KB	(1024L)
62#define	MB	(1024L * 1024L)
63#define	GB	(1024L * 1024L * 1024L)
64#define	MAXB	GB		/* No tera, peta, nor exa. */
65	form = "";
66	if ((p = getenv("BLOCKSIZE")) != NULL && *p != '\0') {
67		if ((n = strtol(p, &ep, 10)) < 0)
68			goto underflow;
69		if (n == 0)
70			n = 1;
71		if (*ep && ep[1])
72			goto fmterr;
73		switch (*ep) {
74		case 'G': case 'g':
75			form = "G";
76			max = MAXB / GB;
77			mul = GB;
78			break;
79		case 'K': case 'k':
80			form = "K";
81			max = MAXB / KB;
82			mul = KB;
83			break;
84		case 'M': case 'm':
85			form = "M";
86			max = MAXB / MB;
87			mul = MB;
88			break;
89		case '\0':
90			max = MAXB;
91			mul = 1;
92			break;
93		default:
94fmterr:			warnx("%s: unknown blocksize", p);
95			n = 512;
96			mul = 1;
97			max = 0;
98			break;
99		}
100		if (n > max) {
101			warnx("maximum blocksize is %ldG", MAXB / GB);
102			n = max;
103		}
104		if ((blocksize = n * mul) < 512) {
105underflow:		warnx("%s: minimum blocksize is 512", p);
106			form = "";
107			blocksize = n = 512;
108		}
109	} else
110		blocksize = n = 512;
111
112	if (headerlenp)
113		*headerlenp =
114		    snprintf(header, sizeof(header), "%ld%s-blocks", n, form);
115	if (blocksizep)
116		*blocksizep = blocksize;
117	return (header);
118}
119