xref: /netbsd-src/lib/libc/gen/getbsize.c (revision d9158b13b5dfe46201430699a3f7a235ecf28df3)
1 /*-
2  * Copyright (c) 1991 The Regents of the University of California.
3  * 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 #ifndef lint
35 /*static char sccsid[] = "from: @(#)getbsize.c	5.3 (Berkeley) 3/9/92";*/
36 static char rcsid[] = "$Id: getbsize.c,v 1.3 1994/01/25 21:03:26 cgd Exp $";
37 #endif /* not lint */
38 
39 #include <err.h>
40 #include <stdio.h>
41 #include <stdlib.h>
42 #include <string.h>
43 
44 char *
45 getbsize(headerlenp, blocksizep)
46 	int *headerlenp;
47 	long *blocksizep;
48 {
49 	static char header[20];
50 	long n, max, mul, blocksize;
51 	char *ep, *p, *form;
52 
53 #define	KB	(1024L)
54 #define	MB	(1024L * 1024L)
55 #define	GB	(1024L * 1024L * 1024L)
56 #define	MAXB	GB		/* No tera, peta, nor exa. */
57 	form = "";
58 	if ((p = getenv("BLOCKSIZE")) != NULL && *p != '\0') {
59 		if ((n = strtol(p, &ep, 10)) < 0)
60 			goto underflow;
61 		if (n == 0)
62 			n = 1;
63 		if (*ep && ep[1])
64 			goto fmterr;
65 		switch (*ep) {
66 		case 'G': case 'g':
67 			form = "G";
68 			max = MAXB / GB;
69 			mul = GB;
70 			break;
71 		case 'K': case 'k':
72 			form = "K";
73 			max = MAXB / KB;
74 			mul = KB;
75 			break;
76 		case 'M': case 'm':
77 			form = "M";
78 			max = MAXB / MB;
79 			mul = MB;
80 			break;
81 		case '\0':
82 			max = MAXB;
83 			mul = 1;
84 			break;
85 		default:
86 fmterr:			warnx("%s: unknown blocksize", p);
87 			n = 512;
88 			mul = 1;
89 			break;
90 		}
91 		if (n > max) {
92 			warnx("maximum blocksize is %dG", MAXB / GB);
93 			n = max;
94 		}
95 		if ((blocksize = n * mul) < 512) {
96 underflow:		warnx("%s: minimum blocksize is 512");
97 			form = "";
98 			blocksize = n = 512;
99 		}
100 	} else
101 		blocksize = n = 512;
102 
103 	*headerlenp = snprintf(header, sizeof(header), "%d%s-blocks", n, form);
104 	*blocksizep = blocksize;
105 	return (header);
106 }
107