getbsize.c revision 181280 
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 * 4. Neither the name of the University nor the names of its contributors
14 *    may be used to endorse or promote products derived from this software
15 *    without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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#if defined(LIBC_SCCS) && !defined(lint)
31static char sccsid[] = "@(#)getbsize.c	8.1 (Berkeley) 6/4/93";
32#endif /* LIBC_SCCS and not lint */
33#include <sys/cdefs.h>
34__FBSDID("$FreeBSD: head/lib/libc/gen/getbsize.c 181280 2008-08-04 06:53:13Z cperciva $");
35
36#include <err.h>
37#include <stdio.h>
38#include <stdlib.h>
39#include <string.h>
40
41char *
42getbsize(headerlenp, blocksizep)
43	int *headerlenp;
44	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