xref: /freebsd/lib/libc/gen/getbsize.c (revision 63dab8eed99114670445270e26cf7193fe55e0fa)
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)
31 static char sccsid[] = "@(#)getbsize.c	8.1 (Berkeley) 6/4/93";
32 #endif /* LIBC_SCCS and not lint */
33 #include <sys/cdefs.h>
34 __FBSDID("$FreeBSD$");
35 
36 #include <err.h>
37 #include <stdio.h>
38 #include <stdlib.h>
39 #include <string.h>
40 
41 char *
42 getbsize(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:
84 fmterr:			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) {
95 underflow:		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