release/src/router/busybox/e2fsprogs/ext2fs/bitmaps.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * bitmaps.c --- routines to read, write, and manipulate the inode and
   4  * block bitmaps.
   5  *
   6  * Copyright (C) 1993, 1994, 1995, 1996 Theodore Ts'o.
   7  *
   8  * %Begin-Header%
   9  * This file may be redistributed under the terms of the GNU Public
  10  * License.
  11  * %End-Header%
  12  */
  13
  14 #include <stdio.h>
  15 #include <string.h>
  16 #if HAVE_UNISTD_H
  17 #include <unistd.h>
  18 #endif
  19 #include <fcntl.h>
  20 #include <time.h>
  21 #if HAVE_SYS_STAT_H
  22 #include <sys/stat.h>
  23 #endif
  24 #if HAVE_SYS_TYPES_H
  25 #include <sys/types.h>
  26 #endif
  27
  28 #include "ext2_fs.h"
  29 #include "ext2fs.h"
  30
  31 static errcode_t make_bitmap(__u32 start, __u32 end, __u32 real_end,
  32                              const char *descr, char *init_map,
  33                              ext2fs_generic_bitmap *ret)
  34 {
  35         ext2fs_generic_bitmap   bitmap;
  36         errcode_t               retval;
  37         size_t                  size;
  38
  39         retval = ext2fs_get_mem(sizeof(struct ext2fs_struct_generic_bitmap),
  40                                 &bitmap);
  41         if (retval)
  42                 return retval;
  43
  44         bitmap->magic = EXT2_ET_MAGIC_GENERIC_BITMAP;
  45         bitmap->fs = NULL;
  46         bitmap->start = start;
  47         bitmap->end = end;
  48         bitmap->real_end = real_end;
  49         bitmap->base_error_code = EXT2_ET_BAD_GENERIC_MARK;
  50         if (descr) {
  51                 retval = ext2fs_get_mem(strlen(descr)+1, &bitmap->description);
  52                 if (retval) {
  53                         ext2fs_free_mem(&bitmap);
  54                         return retval;
  55                 }
  56                 strcpy(bitmap->description, descr);
  57         } else
  58                 bitmap->description = 0;
  59
  60         size = (size_t) (((bitmap->real_end - bitmap->start) / 8) + 1);
  61         retval = ext2fs_get_mem(size, &bitmap->bitmap);
  62         if (retval) {
  63                 ext2fs_free_mem(&bitmap->description);
  64                 ext2fs_free_mem(&bitmap);
  65                 return retval;
  66         }
  67
  68         if (init_map)
  69                 memcpy(bitmap->bitmap, init_map, size);
  70         else
  71                 memset(bitmap->bitmap, 0, size);
  72         *ret = bitmap;
  73         return 0;
  74 }
  75
  76 errcode_t ext2fs_allocate_generic_bitmap(__u32 start,
  77                                          __u32 end,
  78                                          __u32 real_end,
  79                                          const char *descr,
  80                                          ext2fs_generic_bitmap *ret)
  81 {
  82         return make_bitmap(start, end, real_end, descr, 0, ret);
  83 }
  84
  85 errcode_t ext2fs_copy_bitmap(ext2fs_generic_bitmap src,
  86                              ext2fs_generic_bitmap *dest)
  87 {
  88         errcode_t               retval;
  89         ext2fs_generic_bitmap   new_map;
  90
  91         retval = make_bitmap(src->start, src->end, src->real_end,
  92                              src->description, src->bitmap, &new_map);
  93         if (retval)
  94                 return retval;
  95         new_map->magic = src->magic;
  96         new_map->fs = src->fs;
  97         new_map->base_error_code = src->base_error_code;
  98         *dest = new_map;
  99         return 0;
 100 }
 101
 102 void ext2fs_set_bitmap_padding(ext2fs_generic_bitmap map)
 103 {
 104         __u32   i, j;
 105
 106         for (i=map->end+1, j = i - map->start; i <= map->real_end; i++, j++)
 107                 ext2fs_set_bit(j, map->bitmap);
 108 }
 109
 110 errcode_t ext2fs_allocate_inode_bitmap(ext2_filsys fs,
 111                                        const char *descr,
 112                                        ext2fs_inode_bitmap *ret)
 113 {
 114         ext2fs_inode_bitmap bitmap;
 115         errcode_t       retval;
 116         __u32           start, end, real_end;
 117
 118         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
 119
 120         fs->write_bitmaps = ext2fs_write_bitmaps;
 121
 122         start = 1;
 123         end = fs->super->s_inodes_count;
 124         real_end = (EXT2_INODES_PER_GROUP(fs->super) * fs->group_desc_count);
 125
 126         retval = ext2fs_allocate_generic_bitmap(start, end, real_end,
 127                                                 descr, &bitmap);
 128         if (retval)
 129                 return retval;
 130
 131         bitmap->magic = EXT2_ET_MAGIC_INODE_BITMAP;
 132         bitmap->fs = fs;
 133         bitmap->base_error_code = EXT2_ET_BAD_INODE_MARK;
 134
 135         *ret = bitmap;
 136         return 0;
 137 }
 138
 139 errcode_t ext2fs_allocate_block_bitmap(ext2_filsys fs,
 140                                        const char *descr,
 141                                        ext2fs_block_bitmap *ret)
 142 {
 143         ext2fs_block_bitmap bitmap;
 144         errcode_t       retval;
 145         __u32           start, end, real_end;
 146
 147         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
 148
 149         fs->write_bitmaps = ext2fs_write_bitmaps;
 150
 151         start = fs->super->s_first_data_block;
 152         end = fs->super->s_blocks_count-1;
 153         real_end = (EXT2_BLOCKS_PER_GROUP(fs->super)
 154                     * fs->group_desc_count)-1 + start;
 155
 156         retval = ext2fs_allocate_generic_bitmap(start, end, real_end,
 157                                                 descr, &bitmap);
 158         if (retval)
 159                 return retval;
 160
 161         bitmap->magic = EXT2_ET_MAGIC_BLOCK_BITMAP;
 162         bitmap->fs = fs;
 163         bitmap->base_error_code = EXT2_ET_BAD_BLOCK_MARK;
 164
 165         *ret = bitmap;
 166         return 0;
 167 }
 168
 169 errcode_t ext2fs_fudge_inode_bitmap_end(ext2fs_inode_bitmap bitmap,
 170                                         ext2_ino_t end, ext2_ino_t *oend)
 171 {
 172         EXT2_CHECK_MAGIC(bitmap, EXT2_ET_MAGIC_INODE_BITMAP);
 173
 174         if (end > bitmap->real_end)
 175                 return EXT2_ET_FUDGE_INODE_BITMAP_END;
 176         if (oend)
 177                 *oend = bitmap->end;
 178         bitmap->end = end;
 179         return 0;
 180 }
 181
 182 errcode_t ext2fs_fudge_block_bitmap_end(ext2fs_block_bitmap bitmap,
 183                                         blk_t end, blk_t *oend)
 184 {
 185         EXT2_CHECK_MAGIC(bitmap, EXT2_ET_MAGIC_BLOCK_BITMAP);
 186
 187         if (end > bitmap->real_end)
 188                 return EXT2_ET_FUDGE_BLOCK_BITMAP_END;
 189         if (oend)
 190                 *oend = bitmap->end;
 191         bitmap->end = end;
 192         return 0;
 193 }
 194
 195 void ext2fs_clear_inode_bitmap(ext2fs_inode_bitmap bitmap)
 196 {
 197         if (!bitmap || (bitmap->magic != EXT2_ET_MAGIC_INODE_BITMAP))
 198                 return;
 199
 200         memset(bitmap->bitmap, 0,
 201                (size_t) (((bitmap->real_end - bitmap->start) / 8) + 1));
 202 }
 203
 204 void ext2fs_clear_block_bitmap(ext2fs_block_bitmap bitmap)
 205 {
 206         if (!bitmap || (bitmap->magic != EXT2_ET_MAGIC_BLOCK_BITMAP))
 207                 return;
 208
 209         memset(bitmap->bitmap, 0,
 210                (size_t) (((bitmap->real_end - bitmap->start) / 8) + 1));
 211 }