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 Library
   8  * General Public License, version 2.
   9  * %End-Header%
  10  */
  11
  12 #include "config.h"
  13 #include <stdio.h>
  14 #if HAVE_UNISTD_H
  15 #include <unistd.h>
  16 #endif
  17 #include <string.h>
  18 #include <time.h>
  19
  20 #include "ext2_fs.h"
  21 #include "ext2fs.h"
  22
  23 errcode_t ext2fs_read_dir_block3(ext2_filsys fs, blk64_t block,
  24                                  void *buf, int flags EXT2FS_ATTR((unused)))
  25 {
  26         errcode_t       retval;
  27         char            *p, *end;
  28         struct ext2_dir_entry *dirent;
  29         unsigned int    name_len, rec_len;
  30
  31
  32         retval = io_channel_read_blk64(fs->io, block, 1, buf);
  33         if (retval)
  34                 return retval;
  35
  36         p = (char *) buf;
  37         end = (char *) buf + fs->blocksize;
  38         while (p < end-8) {
  39                 dirent = (struct ext2_dir_entry *) p;
  40 #ifdef WORDS_BIGENDIAN
  41                 dirent->inode = ext2fs_swab32(dirent->inode);
  42                 dirent->rec_len = ext2fs_swab16(dirent->rec_len);
  43                 dirent->name_len = ext2fs_swab16(dirent->name_len);
  44 #endif
  45                 name_len = dirent->name_len;
  46 #ifdef WORDS_BIGENDIAN
  47                 if (flags & EXT2_DIRBLOCK_V2_STRUCT)
  48                         dirent->name_len = ext2fs_swab16(dirent->name_len);
  49 #endif
  50                 if ((retval = ext2fs_get_rec_len(fs, dirent, &rec_len)) != 0)
  51                         return retval;
  52                 if ((rec_len < 8) || (rec_len % 4)) {
  53                         rec_len = 8;
  54                         retval = EXT2_ET_DIR_CORRUPTED;
  55                 } else if (((name_len & 0xFF) + 8) > rec_len)
  56                         retval = EXT2_ET_DIR_CORRUPTED;
  57                 p += rec_len;
  58         }
  59         return retval;
  60 }
  61
  62 errcode_t ext2fs_read_dir_block2(ext2_filsys fs, blk_t block,
  63                                  void *buf, int flags EXT2FS_ATTR((unused)))
  64 {
  65         return ext2fs_read_dir_block3(fs, block, buf, flags);
  66 }
  67
  68 errcode_t ext2fs_read_dir_block(ext2_filsys fs, blk_t block,
  69                                  void *buf)
  70 {
  71         return ext2fs_read_dir_block3(fs, block, buf, 0);
  72 }
  73
  74
  75 errcode_t ext2fs_write_dir_block3(ext2_filsys fs, blk64_t block,
  76                                   void *inbuf, int flags EXT2FS_ATTR((unused)))
  77 {
  78 #ifdef WORDS_BIGENDIAN
  79         errcode_t       retval;
  80         char            *p, *end;
  81         char            *buf = 0;
  82         unsigned int    rec_len;
  83         struct ext2_dir_entry *dirent;
  84
  85         retval = ext2fs_get_mem(fs->blocksize, &buf);
  86         if (retval)
  87                 return retval;
  88         memcpy(buf, inbuf, fs->blocksize);
  89         p = buf;
  90         end = buf + fs->blocksize;
  91         while (p < end) {
  92                 dirent = (struct ext2_dir_entry *) p;
  93                 if ((retval = ext2fs_get_rec_len(fs, dirent, &rec_len)) != 0)
  94                         return retval;
  95                 if ((rec_len < 8) ||
  96                     (rec_len % 4)) {
  97                         ext2fs_free_mem(&buf);
  98                         return (EXT2_ET_DIR_CORRUPTED);
  99                 }
 100                 p += rec_len;
 101                 dirent->inode = ext2fs_swab32(dirent->inode);
 102                 dirent->rec_len = ext2fs_swab16(dirent->rec_len);
 103                 dirent->name_len = ext2fs_swab16(dirent->name_len);
 104
 105                 if (flags & EXT2_DIRBLOCK_V2_STRUCT)
 106                         dirent->name_len = ext2fs_swab16(dirent->name_len);
 107         }
 108         retval = io_channel_write_blk64(fs->io, block, 1, buf);
 109         ext2fs_free_mem(&buf);
 110         return retval;
 111 #else
 112         return io_channel_write_blk64(fs->io, block, 1, (char *) inbuf);
 113 #endif
 114 }
 115
 116 errcode_t ext2fs_write_dir_block2(ext2_filsys fs, blk_t block,
 117                                  void *inbuf, int flags EXT2FS_ATTR((unused)))
 118 {
 119         return ext2fs_write_dir_block3(fs, block, inbuf, flags);
 120 }
 121
 122 errcode_t ext2fs_write_dir_block(ext2_filsys fs, blk_t block,
 123                                  void *inbuf)
 124 {
 125         return ext2fs_write_dir_block3(fs, block, inbuf, 0);
 126 }
 127