xref: /freebsd/lib/libc/gen/getbsize.c (revision ae83180158c4c937f170e31eff311b18c0286a93)
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  * 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 #if defined(LIBC_SCCS) && !defined(lint)
35 static char sccsid[] = "@(#)getbsize.c	8.1 (Berkeley) 6/4/93";
36 #endif /* LIBC_SCCS and not lint */
37 #include <sys/cdefs.h>
38 __FBSDID("$FreeBSD$");
39 
40 #include <err.h>
41 #include <stdio.h>
42 #include <stdlib.h>
43 #include <string.h>
44 
45 char *
46 getbsize(headerlenp, blocksizep)
47 	int *headerlenp;
48 	long *blocksizep;
49 {
50 	static char header[20];
51 	long n, max, mul, blocksize;
52 	char *ep, *p, *form;
53 
54 #define	KB	(1024L)
55 #define	MB	(1024L * 1024L)
56 #define	GB	(1024L * 1024L * 1024L)
57 #define	MAXB	GB		/* No tera, peta, nor exa. */
58 	form = "";
59 	if ((p = getenv("BLOCKSIZE")) != NULL && *p != '\0') {
60 		if ((n = strtol(p, &ep, 10)) < 0)
61 			goto underflow;
62 		if (n == 0)
63 			n = 1;
64 		if (*ep && ep[1])
65 			goto fmterr;
66 		switch (*ep) {
67 		case 'G': case 'g':
68 			form = "G";
69 			max = MAXB / GB;
70 			mul = GB;
71 			break;
72 		case 'K': case 'k':
73 			form = "K";
74 			max = MAXB / KB;
75 			mul = KB;
76 			break;
77 		case 'M': case 'm':
78 			form = "M";
79 			max = MAXB / MB;
80 			mul = MB;
81 			break;
82 		case '\0':
83 			max = MAXB;
84 			mul = 1;
85 			break;
86 		default:
87 fmterr:			warnx("%s: unknown blocksize", p);
88 			n = 512;
89 			mul = 1;
90 			break;
91 		}
92 		if (n > max) {
93 			warnx("maximum blocksize is %ldG", MAXB / GB);
94 			n = max;
95 		}
96 		if ((blocksize = n * mul) < 512) {
97 underflow:		warnx("minimum blocksize is 512");
98 			form = "";
99 			blocksize = n = 512;
100 		}
101 	} else
102 		blocksize = n = 512;
103 
104 	(void)snprintf(header, sizeof(header), "%ld%s-blocks", n, form);
105 	*headerlenp = strlen(header);
106 	*blocksizep = blocksize;
107 	return (header);
108 }
109