mkfs/cbm.c

   1 /*
   2         cbm.c (09.11.10)
   3         Clusters Bitmap creation code.
   4
   5         Free exFAT implementation.
   6         Copyright (C) 2011-2018  Andrew Nayenko
   7
   8         This program is free software; you can redistribute it and/or modify
   9         it under the terms of the GNU General Public License as published by
  10         the Free Software Foundation, either version 2 of the License, or
  11         (at your option) any later version.
  12
  13         This program is distributed in the hope that it will be useful,
  14         but WITHOUT ANY WARRANTY; without even the implied warranty of
  15         MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16         GNU General Public License for more details.
  17
  18         You should have received a copy of the GNU General Public License along
  19         with this program; if not, write to the Free Software Foundation, Inc.,
  20         51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  21 */
  22
  23 #include "cbm.h"
  24 #include "fat.h"
  25 #include "uct.h"
  26 #include "rootdir.h"
  27 #include <limits.h>
  28 #include <string.h>
  29
  30 static off_t cbm_alignment(void)
  31 {
  32         return get_cluster_size();
  33 }
  34
  35 static off_t cbm_size(void)
  36 {
  37         return DIV_ROUND_UP(
  38                         (get_volume_size() - get_position(&cbm)) / get_cluster_size(),
  39                         CHAR_BIT);
  40 }
  41
  42 static int cbm_write(struct exfat_dev* dev)
  43 {
  44         uint32_t allocated_clusters =
  45                         DIV_ROUND_UP(cbm.get_size(), get_cluster_size()) +
  46                         DIV_ROUND_UP(uct.get_size(), get_cluster_size()) +
  47                         DIV_ROUND_UP(rootdir.get_size(), get_cluster_size());
  48         size_t bitmap_size = ROUND_UP(allocated_clusters, CHAR_BIT);
  49         bitmap_t* bitmap = malloc(BMAP_SIZE(bitmap_size));
  50         size_t i;
  51
  52         if (bitmap == NULL)
  53         {
  54                 exfat_error("failed to allocate bitmap of %zu bytes",
  55                                 BMAP_SIZE(bitmap_size));
  56                 return 1;
  57         }
  58         memset(bitmap, 0, BMAP_SIZE(bitmap_size));
  59
  60         for (i = 0; i < bitmap_size; i++)
  61                 if (i < allocated_clusters)
  62                         BMAP_SET(bitmap, i);
  63         if (exfat_write(dev, bitmap, bitmap_size / CHAR_BIT) < 0)
  64         {
  65                 free(bitmap);
  66                 exfat_error("failed to write bitmap of %zu bytes",
  67                                 bitmap_size / CHAR_BIT);
  68                 return 1;
  69         }
  70         free(bitmap);
  71         return 0;
  72 }
  73
  74 const struct fs_object cbm =
  75 {
  76         .get_alignment = cbm_alignment,
  77         .get_size = cbm_size,
  78         .write = cbm_write,
  79 };