lib/libc/gen/getbsize.c

   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  * @(#)getbsize.c       8.1 (Berkeley) 6/4/93
  30  * $FreeBSD: src/lib/libc/gen/getbsize.c,v 1.9 2008/08/04 06:53:13 cperciva Exp $
  31  * $DragonFly: src/lib/libc/gen/getbsize.c,v 1.4 2005/11/13 00:07:42 swildner Exp $
  32  */
  33
  34 #include <err.h>
  35 #include <stdio.h>
  36 #include <stdlib.h>
  37 #include <string.h>
  38
  39 char *
  40 getbsize(int *headerlenp, long *blocksizep)
  41 {
  42         static char header[20];
  43         long n, max, mul, blocksize;
  44         char *ep, *p;
  45         const char *form;
  46
  47 #define KB      (1024L)
  48 #define MB      (1024L * 1024L)
  49 #define GB      (1024L * 1024L * 1024L)
  50 #define MAXB    GB              /* No tera, peta, nor exa. */
  51         form = "";
  52         if ((p = getenv("BLOCKSIZE")) != NULL && *p != '\0') {
  53                 if ((n = strtol(p, &ep, 10)) < 0)
  54                         goto underflow;
  55                 if (n == 0)
  56                         n = 1;
  57                 if (*ep && ep[1])
  58                         goto fmterr;
  59                 switch (*ep) {
  60                 case 'G': case 'g':
  61                         form = "G";
  62                         max = MAXB / GB;
  63                         mul = GB;
  64                         break;
  65                 case 'K': case 'k':
  66                         form = "K";
  67                         max = MAXB / KB;
  68                         mul = KB;
  69                         break;
  70                 case 'M': case 'm':
  71                         form = "M";
  72                         max = MAXB / MB;
  73                         mul = MB;
  74                         break;
  75                 case '\0':
  76                         max = MAXB;
  77                         mul = 1;
  78                         break;
  79                 default:
  80 fmterr:                 warnx("%s: unknown blocksize", p);
  81                         n = 512;
  82                         max = MAXB;
  83                         mul = 1;
  84                         break;
  85                 }
  86                 if (n > max) {
  87                         warnx("maximum blocksize is %ldG", MAXB / GB);
  88                         n = max;
  89                 }
  90                 if ((blocksize = n * mul) < 512) {
  91 underflow:              warnx("minimum blocksize is 512");
  92                         form = "";
  93                         blocksize = n = 512;
  94                 }
  95         } else
  96                 blocksize = n = 512;
  97
  98         snprintf(header, sizeof(header), "%ld%s-blocks", n, form);
  99         *headerlenp = strlen(header);
 100         *blocksizep = blocksize;
 101         return (header);
 102 }