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 * 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