1 /* $OpenBSD: getbsize.c,v 1.11 2015/08/31 02:53:57 guenther Exp $ */
2 /*-
3 * Copyright (c) 1991, 1993
4 * The Regents of the University of California. All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 * 3. Neither the name of the University nor the names of its contributors
15 * may be used to endorse or promote products derived from this software
16 * without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 * SUCH DAMAGE.
29 */
30
31 #include <err.h>
32 #include <stdio.h>
33 #include <stdlib.h>
34 #include <string.h>
35
36 char *
getbsize(int * headerlenp,long * blocksizep)37 getbsize(int *headerlenp, long *blocksizep)
38 {
39 static char header[20];
40 long n, max, mul, blocksize;
41 char *ep, *p, *form;
42
43 #define KB (1024)
44 #define MB (1024 * 1024)
45 #define GB (1024 * 1024 * 1024)
46 #define MAXB GB /* No tera, peta, nor exa. */
47 form = "";
48 if ((p = getenv("BLOCKSIZE")) != NULL && *p != '\0') {
49 if ((n = strtol(p, &ep, 10)) < 0)
50 goto underflow;
51 if (n == 0)
52 n = 1;
53 if (*ep && ep[1])
54 goto fmterr;
55 switch (*ep) {
56 case 'G': case 'g':
57 form = "G";
58 max = MAXB / GB;
59 mul = GB;
60 break;
61 case 'K': case 'k':
62 form = "K";
63 max = MAXB / KB;
64 mul = KB;
65 break;
66 case 'M': case 'm':
67 form = "M";
68 max = MAXB / MB;
69 mul = MB;
70 break;
71 case '\0':
72 max = MAXB;
73 mul = 1;
74 break;
75 default:
76 fmterr: warnx("%s: unknown blocksize", p);
77 n = 512;
78 max = MAXB;
79 mul = 1;
80 break;
81 }
82 if (n > max) {
83 warnx("maximum blocksize is %dG", MAXB / GB);
84 n = max;
85 }
86 if ((blocksize = n * mul) < 512) {
87 underflow: warnx("%s: minimum blocksize is 512", p);
88 form = "";
89 blocksize = n = 512;
90 }
91 } else
92 blocksize = n = 512;
93
94 *headerlenp = snprintf(header, sizeof(header), "%ld%s-blocks", n, form);
95 if (*headerlenp < 0)
96 *headerlenp = 0;
97 else if (*headerlenp >= sizeof(header))
98 *headerlenp = sizeof(header) - 1;
99 *blocksizep = blocksize;
100 return (header);
101 }
102