xref: /netbsd-src/lib/libc/gen/getbsize.c (revision 1f2744e6e4915c9da2a3f980279398c4cf7d5e6d)
1 /*	$NetBSD: getbsize.c,v 1.6 1995/02/25 13:41:34 cgd 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 #ifndef lint
37 #if 0
38 static char sccsid[] = "@(#)getbsize.c	8.1 (Berkeley) 6/4/93";
39 #else
40 static char rcsid[] = "$NetBSD: getbsize.c,v 1.6 1995/02/25 13:41:34 cgd Exp $";
41 #endif
42 #endif /* not lint */
43 
44 #include <err.h>
45 #include <stdio.h>
46 #include <stdlib.h>
47 #include <string.h>
48 
49 char *
50 getbsize(headerlenp, blocksizep)
51 	int *headerlenp;
52 	long *blocksizep;
53 {
54 	static char header[20];
55 	long n, max, mul, blocksize;
56 	char *ep, *p, *form;
57 
58 #define	KB	(1024L)
59 #define	MB	(1024L * 1024L)
60 #define	GB	(1024L * 1024L * 1024L)
61 #define	MAXB	GB		/* No tera, peta, nor exa. */
62 	form = "";
63 	if ((p = getenv("BLOCKSIZE")) != NULL && *p != '\0') {
64 		if ((n = strtol(p, &ep, 10)) < 0)
65 			goto underflow;
66 		if (n == 0)
67 			n = 1;
68 		if (*ep && ep[1])
69 			goto fmterr;
70 		switch (*ep) {
71 		case 'G': case 'g':
72 			form = "G";
73 			max = MAXB / GB;
74 			mul = GB;
75 			break;
76 		case 'K': case 'k':
77 			form = "K";
78 			max = MAXB / KB;
79 			mul = KB;
80 			break;
81 		case 'M': case 'm':
82 			form = "M";
83 			max = MAXB / MB;
84 			mul = MB;
85 			break;
86 		case '\0':
87 			max = MAXB;
88 			mul = 1;
89 			break;
90 		default:
91 fmterr:			_warnx("%s: unknown blocksize", p);
92 			n = 512;
93 			mul = 1;
94 			break;
95 		}
96 		if (n > max) {
97 			_warnx("maximum blocksize is %dG", MAXB / GB);
98 			n = max;
99 		}
100 		if ((blocksize = n * mul) < 512) {
101 underflow:		_warnx("%s: minimum blocksize is 512");
102 			form = "";
103 			blocksize = n = 512;
104 		}
105 	} else
106 		blocksize = n = 512;
107 
108 	*headerlenp = snprintf(header, sizeof(header), "%d%s-blocks", n, form);
109 	*blocksizep = blocksize;
110 	return (header);
111 }
112