xref: /netbsd-src/lib/libc/gen/getbsize.c (revision 23c8222edbfb0f0932d88a8351d3a0cf817dfb9e)
1 /*	$NetBSD: getbsize.c,v 1.15 2003/08/07 16:42:48 agc 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
35 static char sccsid[] = "@(#)getbsize.c	8.1 (Berkeley) 6/4/93";
36 #else
37 __RCSID("$NetBSD: getbsize.c,v 1.15 2003/08/07 16:42:48 agc 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 
53 char *
54 getbsize(headerlenp, blocksizep)
55 	int *headerlenp;
56 	long *blocksizep;
57 {
58 	static char header[20];
59 	long n, max, mul, blocksize;
60 	char *ep, *p, *form;
61 
62 #define	KB	(1024L)
63 #define	MB	(1024L * 1024L)
64 #define	GB	(1024L * 1024L * 1024L)
65 #define	MAXB	GB		/* No tera, peta, nor exa. */
66 	form = "";
67 	if ((p = getenv("BLOCKSIZE")) != NULL && *p != '\0') {
68 		if ((n = strtol(p, &ep, 10)) < 0)
69 			goto underflow;
70 		if (n == 0)
71 			n = 1;
72 		if (*ep && ep[1])
73 			goto fmterr;
74 		switch (*ep) {
75 		case 'G': case 'g':
76 			form = "G";
77 			max = MAXB / GB;
78 			mul = GB;
79 			break;
80 		case 'K': case 'k':
81 			form = "K";
82 			max = MAXB / KB;
83 			mul = KB;
84 			break;
85 		case 'M': case 'm':
86 			form = "M";
87 			max = MAXB / MB;
88 			mul = MB;
89 			break;
90 		case '\0':
91 			max = MAXB;
92 			mul = 1;
93 			break;
94 		default:
95 fmterr:			warnx("%s: unknown blocksize", p);
96 			n = 512;
97 			mul = 1;
98 			max = 0;
99 			break;
100 		}
101 		if (n > max) {
102 			warnx("maximum blocksize is %ldG", MAXB / GB);
103 			n = max;
104 		}
105 		if ((blocksize = n * mul) < 512) {
106 underflow:		warnx("%s: minimum blocksize is 512", p);
107 			form = "";
108 			blocksize = n = 512;
109 		}
110 	} else
111 		blocksize = n = 512;
112 
113 	if (headerlenp)
114 		*headerlenp =
115 		    snprintf(header, sizeof(header), "%ld%s-blocks", n, form);
116 	if (blocksizep)
117 		*blocksizep = blocksize;
118 	return (header);
119 }
120