getbsize.c revision 108445 
1/*-
2 * Copyright (c) 1991, 1993
3 *	The Regents of the University of California.  All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 * 3. All advertising materials mentioning features or use of this software
14 *    must display the following acknowledgement:
15 *	This product includes software developed by the University of
16 *	California, Berkeley and its contributors.
17 * 4. Neither the name of the University nor the names of its contributors
18 *    may be used to endorse or promote products derived from this software
19 *    without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 */
33
34#if defined(LIBC_SCCS) && !defined(lint)
35static char sccsid[] = "@(#)getbsize.c	8.1 (Berkeley) 6/4/93";
36#endif /* LIBC_SCCS and not lint */
37#include <sys/cdefs.h>
38__FBSDID("$FreeBSD: head/lib/libc/gen/getbsize.c 108445 2002-12-30 11:12:16Z obrien $");
39
40#include <err.h>
41#include <stdio.h>
42#include <stdlib.h>
43#include <string.h>
44
45char *
46getbsize(headerlenp, blocksizep)
47	int *headerlenp;
48	long *blocksizep;
49{
50	static char header[20];
51	long n, max, mul, blocksize;
52	char *ep, *p;
53	const char *form;
54
55#define	KB	(1024L)
56#define	MB	(1024L * 1024L)
57#define	GB	(1024L * 1024L * 1024L)
58#define	MAXB	GB		/* No tera, peta, nor exa. */
59	form = "";
60	if ((p = getenv("BLOCKSIZE")) != NULL && *p != '\0') {
61		if ((n = strtol(p, &ep, 10)) < 0)
62			goto underflow;
63		if (n == 0)
64			n = 1;
65		if (*ep && ep[1])
66			goto fmterr;
67		switch (*ep) {
68		case 'G': case 'g':
69			form = "G";
70			max = MAXB / GB;
71			mul = GB;
72			break;
73		case 'K': case 'k':
74			form = "K";
75			max = MAXB / KB;
76			mul = KB;
77			break;
78		case 'M': case 'm':
79			form = "M";
80			max = MAXB / MB;
81			mul = MB;
82			break;
83		case '\0':
84			max = MAXB;
85			mul = 1;
86			break;
87		default:
88fmterr:			warnx("%s: unknown blocksize", p);
89			n = 512;
90			mul = 1;
91			break;
92		}
93		if (n > max) {
94			warnx("maximum blocksize is %ldG", MAXB / GB);
95			n = max;
96		}
97		if ((blocksize = n * mul) < 512) {
98underflow:		warnx("minimum blocksize is 512");
99			form = "";
100			blocksize = n = 512;
101		}
102	} else
103		blocksize = n = 512;
104
105	(void)snprintf(header, sizeof(header), "%ld%s-blocks", n, form);
106	*headerlenp = strlen(header);
107	*blocksizep = blocksize;
108	return (header);
109}
110