lib/ext2fs/dirblock.c

   1 /*
   2  * dirblock.c --- directory block routines.
   3  *
   4  * Copyright (C) 1995, 1996 Theodore Ts'o.
   5  *
   6  * %Begin-Header%
   7  * This file may be redistributed under the terms of the GNU Public
   8  * License.
   9  * %End-Header%
  10  */
  11
  12 #include <stdio.h>
  13 #if HAVE_UNISTD_H
  14 #include <unistd.h>
  15 #endif
  16 #include <string.h>
  17 #include <time.h>
  18
  19 #include "ext2_fs.h"
  20 #include "ext2fs.h"
  21
  22 errcode_t ext2fs_read_dir_block2(ext2_filsys fs, blk_t block,
  23                                  void *buf, int flags EXT2FS_ATTR((unused)))
  24 {
  25         errcode_t       retval;
  26         char            *p, *end;
  27         struct ext2_dir_entry *dirent;
  28         unsigned int    name_len, rec_len;
  29
  30
  31         retval = io_channel_read_blk(fs->io, block, 1, buf);
  32         if (retval)
  33                 return retval;
  34
  35         p = (char *) buf;
  36         end = (char *) buf + fs->blocksize;
  37         while (p < end-8) {
  38                 dirent = (struct ext2_dir_entry *) p;
  39 #ifdef WORDS_BIGENDIAN
  40                 dirent->inode = ext2fs_swab32(dirent->inode);
  41                 dirent->rec_len = ext2fs_swab16(dirent->rec_len);
  42                 dirent->name_len = ext2fs_swab16(dirent->name_len);
  43 #endif
  44                 name_len = dirent->name_len;
  45 #ifdef WORDS_BIGENDIAN
  46                 if (flags & EXT2_DIRBLOCK_V2_STRUCT)
  47                         dirent->name_len = ext2fs_swab16(dirent->name_len);
  48 #endif
  49                 rec_len = (dirent->rec_len || fs->blocksize < 65536) ?
  50                         dirent->rec_len : 65536;
  51                 if ((rec_len < 8) || (rec_len % 4)) {
  52                         rec_len = 8;
  53                         retval = EXT2_ET_DIR_CORRUPTED;
  54                 } else if (((name_len & 0xFF) + 8) > rec_len)
  55                         retval = EXT2_ET_DIR_CORRUPTED;
  56                 p += rec_len;
  57         }
  58         return retval;
  59 }
  60
  61 errcode_t ext2fs_read_dir_block(ext2_filsys fs, blk_t block,
  62                                  void *buf)
  63 {
  64         return ext2fs_read_dir_block2(fs, block, buf, 0);
  65 }
  66
  67
  68 errcode_t ext2fs_write_dir_block2(ext2_filsys fs, blk_t block,
  69                                   void *inbuf, int flags EXT2FS_ATTR((unused)))
  70 {
  71 #ifdef WORDS_BIGENDIAN
  72         errcode_t       retval;
  73         char            *p, *end;
  74         char            *buf = 0;
  75         int             rec_len;
  76         struct ext2_dir_entry *dirent;
  77
  78         retval = ext2fs_get_mem(fs->blocksize, &buf);
  79         if (retval)
  80                 return retval;
  81         memcpy(buf, inbuf, fs->blocksize);
  82         p = buf;
  83         end = buf + fs->blocksize;
  84         while (p < end) {
  85                 dirent = (struct ext2_dir_entry *) p;
  86                 rec_len = (dirent->rec_len || fs->blocksize < 65536) ?
  87                         dirent->rec_len : 65536;
  88                 if ((rec_len < 8) ||
  89                     (rec_len % 4)) {
  90                         ext2fs_free_mem(&buf);
  91                         return (EXT2_ET_DIR_CORRUPTED);
  92                 }
  93                 p += rec_len;
  94                 dirent->inode = ext2fs_swab32(dirent->inode);
  95                 dirent->rec_len = ext2fs_swab16(dirent->rec_len);
  96                 dirent->name_len = ext2fs_swab16(dirent->name_len);
  97
  98                 if (flags & EXT2_DIRBLOCK_V2_STRUCT)
  99                         dirent->name_len = ext2fs_swab16(dirent->name_len);
 100         }
 101         retval = io_channel_write_blk(fs->io, block, 1, buf);
 102         ext2fs_free_mem(&buf);
 103         return retval;
 104 #else
 105         return io_channel_write_blk(fs->io, block, 1, (char *) inbuf);
 106 #endif
 107 }
 108
 109
 110 errcode_t ext2fs_write_dir_block(ext2_filsys fs, blk_t block,
 111                                  void *inbuf)
 112 {
 113         return ext2fs_write_dir_block2(fs, block, inbuf, 0);
 114 }
 115