xref: /netbsd-src/lib/libc/gen/getbsize.c (revision 1394f01b4a9e99092957ca5d824d67219565d9b5)
1 /*	$NetBSD: getbsize.c,v 1.9 1997/07/13 18:59:34 christos 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. All advertising materials mentioning features or use of this software
16  *    must display the following acknowledgement:
17  *	This product includes software developed by the University of
18  *	California, Berkeley and its contributors.
19  * 4. Neither the name of the University nor the names of its contributors
20  *    may be used to endorse or promote products derived from this software
21  *    without specific prior written permission.
22  *
23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33  * SUCH DAMAGE.
34  */
35 
36 #include <sys/cdefs.h>
37 #if defined(LIBC_SCCS) && !defined(lint)
38 #if 0
39 static char sccsid[] = "@(#)getbsize.c	8.1 (Berkeley) 6/4/93";
40 #else
41 __RCSID("$NetBSD: getbsize.c,v 1.9 1997/07/13 18:59:34 christos Exp $");
42 #endif
43 #endif /* not lint */
44 
45 #include "namespace.h"
46 #include <err.h>
47 #include <stdio.h>
48 #include <stdlib.h>
49 #include <string.h>
50 
51 char *
52 getbsize(headerlenp, blocksizep)
53 	int *headerlenp;
54 	long *blocksizep;
55 {
56 	static char header[20];
57 	long n, max, mul, blocksize;
58 	char *ep, *p, *form;
59 
60 #define	KB	(1024L)
61 #define	MB	(1024L * 1024L)
62 #define	GB	(1024L * 1024L * 1024L)
63 #define	MAXB	GB		/* No tera, peta, nor exa. */
64 	form = "";
65 	if ((p = getenv("BLOCKSIZE")) != NULL && *p != '\0') {
66 		if ((n = strtol(p, &ep, 10)) < 0)
67 			goto underflow;
68 		if (n == 0)
69 			n = 1;
70 		if (*ep && ep[1])
71 			goto fmterr;
72 		switch (*ep) {
73 		case 'G': case 'g':
74 			form = "G";
75 			max = MAXB / GB;
76 			mul = GB;
77 			break;
78 		case 'K': case 'k':
79 			form = "K";
80 			max = MAXB / KB;
81 			mul = KB;
82 			break;
83 		case 'M': case 'm':
84 			form = "M";
85 			max = MAXB / MB;
86 			mul = MB;
87 			break;
88 		case '\0':
89 			max = MAXB;
90 			mul = 1;
91 			break;
92 		default:
93 fmterr:			warnx("%s: unknown blocksize", p);
94 			n = 512;
95 			mul = 1;
96 			max = 0;
97 			break;
98 		}
99 		if (n > max) {
100 			warnx("maximum blocksize is %ldG", MAXB / GB);
101 			n = max;
102 		}
103 		if ((blocksize = n * mul) < 512) {
104 underflow:		warnx("%s: minimum blocksize is 512", p);
105 			form = "";
106 			blocksize = n = 512;
107 		}
108 	} else
109 		blocksize = n = 512;
110 
111 	*headerlenp = snprintf(header, sizeof(header), "%ld%s-blocks", n, form);
112 	*blocksizep = blocksize;
113 	return (header);
114 }
115