lib/libc/gen/getbsize.c

   1 /*      $NetBSD: getbsize.c,v 1.17 2012/06/25 22:32:43 abs Exp $        */
   2
   3 /*-
   4  * Copyright (c) 1991, 1993
   5  *      The Regents of the University of California.  All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  * 3. Neither the name of the University nor the names of its contributors
  16  *    may be used to endorse or promote products derived from this software
  17  *    without specific prior written permission.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  29  * SUCH DAMAGE.
  30  */
  31
  32 #include <sys/cdefs.h>
  33 #if defined(LIBC_SCCS) && !defined(lint)
  34 #if 0
  35 static char sccsid[] = "@(#)getbsize.c  8.1 (Berkeley) 6/4/93";
  36 #else
  37 __RCSID("$NetBSD: getbsize.c,v 1.17 2012/06/25 22:32:43 abs Exp $");
  38 #endif
  39 #endif /* not lint */
  40
  41 #include "namespace.h"
  42
  43 #include <assert.h>
  44 #include <err.h>
  45 #include <stdio.h>
  46 #include <stdlib.h>
  47 #include <string.h>
  48
  49 #ifdef __weak_alias
  50 __weak_alias(getbsize,_getbsize)
  51 #endif
  52
  53 char *
  54 getbsize(int *headerlenp, long *blocksizep)
  55 {
  56         static char header[20];
  57         long n, max, mul, blocksize;
  58         char *ep, *p;
  59         const char *form;
  60
  61 #define KB      (1024L)
  62 #define MB      (1024L * 1024L)
  63 #define GB      (1024L * 1024L * 1024L)
  64 #define MAXB    GB              /* No tera, peta, nor exa. */
  65         form = "";
  66         if ((p = getenv("BLOCKSIZE")) != NULL && *p != '\0') {
  67                 if ((n = strtol(p, &ep, 10)) < 0)
  68                         goto underflow;
  69                 if (n == 0)
  70                         n = 1;
  71                 if (*ep && ep[1])
  72                         goto fmterr;
  73                 switch (*ep) {
  74                 case 'G': case 'g':
  75                         form = "G";
  76                         max = MAXB / GB;
  77                         mul = GB;
  78                         break;
  79                 case 'K': case 'k':
  80                         form = "K";
  81                         max = MAXB / KB;
  82                         mul = KB;
  83                         break;
  84                 case 'M': case 'm':
  85                         form = "M";
  86                         max = MAXB / MB;
  87                         mul = MB;
  88                         break;
  89                 case '\0':
  90                         max = MAXB;
  91                         mul = 1;
  92                         break;
  93                 default:
  94 fmterr:                 warnx("%s: unknown blocksize", p);
  95                         n = 512;
  96                         mul = 1;
  97                         max = 0;
  98                         break;
  99                 }
 100                 if (n > max) {
 101                         warnx("maximum blocksize is %ldG", MAXB / GB);
 102                         n = max;
 103                 }
 104                 if ((blocksize = n * mul) < 512) {
 105 underflow:              warnx("%s: minimum blocksize is 512", p);
 106                         form = "";
 107                         blocksize = n = 512;
 108                 }
 109         } else
 110                 blocksize = n = 512;
 111
 112         if (headerlenp)
 113                 *headerlenp =
 114                     snprintf(header, sizeof(header), "%ld%s-blocks", n, form);
 115         if (blocksizep)
 116                 *blocksizep = blocksize;
 117         return (header);
 118 }