/*      $NetBSD: getbsize.c,v 1.17 2012/06/25 22:32:43 abs Exp $        */

/*-
* Copyright (c) 1991, 1993
*      The Regents of the University of California.  All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
*    notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
*    notice, this list of conditions and the following disclaimer in the
*    documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
*    may be used to endorse or promote products derived from this software
*    without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/

#include <sys/cdefs.h>
#if defined(LIBC_SCCS) && !defined(lint)
#if 0
static char sccsid[] = "@(#)getbsize.c  8.1 (Berkeley) 6/4/93";
#else
__RCSID("$NetBSD: getbsize.c,v 1.17 2012/06/25 22:32:43 abs Exp $");
#endif
#endif /* not lint */

#include "namespace.h"

#include <assert.h>
#include <err.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#ifdef __weak_alias
__weak_alias(getbsize,_getbsize)
#endif

char *
getbsize(int *headerlenp, long *blocksizep)
{
       static char header[20];
       long n, max, mul, blocksize;
       char *ep, *p;
       const char *form;

#define KB      (1024L)
#define MB      (1024L * 1024L)
#define GB      (1024L * 1024L * 1024L)
#define MAXB    GB              /* No tera, peta, nor exa. */
       form = "";
       if ((p = getenv("BLOCKSIZE")) != NULL && *p != '\0') {
               if ((n = strtol(p, &ep, 10)) < 0)
                       goto underflow;
               if (n == 0)
                       n = 1;
               if (*ep && ep[1])
                       goto fmterr;
               switch (*ep) {
               case 'G': case 'g':
                       form = "G";
                       max = MAXB / GB;
                       mul = GB;
                       break;
               case 'K': case 'k':
                       form = "K";
                       max = MAXB / KB;
                       mul = KB;
                       break;
               case 'M': case 'm':
                       form = "M";
                       max = MAXB / MB;
                       mul = MB;
                       break;
               case '\0':
                       max = MAXB;
                       mul = 1;
                       break;
               default:
fmterr:                 warnx("%s: unknown blocksize", p);
                       n = 512;
                       mul = 1;
                       max = 0;
                       break;
               }
               if (n > max) {
                       warnx("maximum blocksize is %ldG", MAXB / GB);
                       n = max;
               }
               if ((blocksize = n * mul) < 512) {
underflow:              warnx("%s: minimum blocksize is 512", p);
                       form = "";
                       blocksize = n = 512;
               }
       } else
               blocksize = n = 512;

       if (headerlenp)
               *headerlenp =
                   snprintf(header, sizeof(header), "%ld%s-blocks", n, form);
       if (blocksizep)
               *blocksizep = blocksize;
       return (header);
}