xref: /freebsd/lib/libc/gen/getbsize.c (revision 2357939bc239bd5334a169b62313806178dd8f30)
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;
53 	const char *form;
54 
55 #define	KB	(1024L)
56 #define	MB	(1024L * 1024L)
57 #define	GB	(1024L * 1024L * 1024L)
58 #define	MAXB	GB		/* No tera, peta, nor exa. */
59 	form = "";
60 	if ((p = getenv("BLOCKSIZE")) != NULL && *p != '\0') {
61 		if ((n = strtol(p, &ep, 10)) < 0)
62 			goto underflow;
63 		if (n == 0)
64 			n = 1;
65 		if (*ep && ep[1])
66 			goto fmterr;
67 		switch (*ep) {
68 		case 'G': case 'g':
69 			form = "G";
70 			max = MAXB / GB;
71 			mul = GB;
72 			break;
73 		case 'K': case 'k':
74 			form = "K";
75 			max = MAXB / KB;
76 			mul = KB;
77 			break;
78 		case 'M': case 'm':
79 			form = "M";
80 			max = MAXB / MB;
81 			mul = MB;
82 			break;
83 		case '\0':
84 			max = MAXB;
85 			mul = 1;
86 			break;
87 		default:
88 fmterr:			warnx("%s: unknown blocksize", p);
89 			n = 512;
90 			mul = 1;
91 			break;
92 		}
93 		if (n > max) {
94 			warnx("maximum blocksize is %ldG", MAXB / GB);
95 			n = max;
96 		}
97 		if ((blocksize = n * mul) < 512) {
98 underflow:		warnx("minimum blocksize is 512");
99 			form = "";
100 			blocksize = n = 512;
101 		}
102 	} else
103 		blocksize = n = 512;
104 
105 	(void)snprintf(header, sizeof(header), "%ld%s-blocks", n, form);
106 	*headerlenp = strlen(header);
107 	*blocksizep = blocksize;
108 	return (header);
109 }
110