e2fsprogs/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 #ifdef EXT2FS_ENABLE_SWAPFS
  30         unsigned int do_swap;
  31 #endif
  32
  33         retval = io_channel_read_blk(fs->io, block, 1, buf);
  34         if (retval)
  35                 return retval;
  36 #ifdef EXT2FS_ENABLE_SWAPFS
  37         do_swap = (fs->flags & (EXT2_FLAG_SWAP_BYTES|
  38                                 EXT2_FLAG_SWAP_BYTES_READ)) != 0;
  39 #endif
  40         p = (char *) buf;
  41         end = (char *) buf + fs->blocksize;
  42         while (p < end-8) {
  43                 dirent = (struct ext2_dir_entry *) p;
  44 #ifdef EXT2FS_ENABLE_SWAPFS
  45                 if (do_swap) {
  46                         dirent->inode = ext2fs_swab32(dirent->inode);
  47                         dirent->rec_len = ext2fs_swab16(dirent->rec_len);
  48                         dirent->name_len = ext2fs_swab16(dirent->name_len);
  49                 }
  50 #endif
  51                 name_len = dirent->name_len;
  52 #ifdef WORDS_BIGENDIAN
  53                 if (flags & EXT2_DIRBLOCK_V2_STRUCT)
  54                         dirent->name_len = ext2fs_swab16(dirent->name_len);
  55 #endif
  56                 rec_len = dirent->rec_len;
  57                 if ((rec_len < 8) || (rec_len % 4)) {
  58                         rec_len = 8;
  59                         retval = EXT2_ET_DIR_CORRUPTED;
  60                 }
  61                 if (((name_len & 0xFF) + 8) > dirent->rec_len)
  62                         retval = EXT2_ET_DIR_CORRUPTED;
  63                 p += rec_len;
  64         }
  65         return retval;
  66 }
  67
  68 errcode_t ext2fs_read_dir_block(ext2_filsys fs, blk_t block,
  69                                  void *buf)
  70 {
  71         return ext2fs_read_dir_block2(fs, block, buf, 0);
  72 }
  73
  74
  75 errcode_t ext2fs_write_dir_block2(ext2_filsys fs, blk_t block,
  76                                   void *inbuf, int flags EXT2FS_ATTR((unused)))
  77 {
  78 #ifdef EXT2FS_ENABLE_SWAPFS
  79         int             do_swap = 0;
  80         errcode_t       retval;
  81         char            *p, *end;
  82         char            *buf = 0;
  83         struct ext2_dir_entry *dirent;
  84
  85         if ((fs->flags & EXT2_FLAG_SWAP_BYTES) ||
  86             (fs->flags & EXT2_FLAG_SWAP_BYTES_WRITE))
  87                 do_swap = 1;
  88
  89 #ifndef WORDS_BIGENDIAN
  90         if (!do_swap)
  91                 return io_channel_write_blk(fs->io, block, 1, (char *) inbuf);
  92 #endif
  93
  94         retval = ext2fs_get_mem(fs->blocksize, &buf);
  95         if (retval)
  96                 return retval;
  97         memcpy(buf, inbuf, fs->blocksize);
  98         p = buf;
  99         end = buf + fs->blocksize;
 100         while (p < end) {
 101                 dirent = (struct ext2_dir_entry *) p;
 102                 if ((dirent->rec_len < 8) ||
 103                     (dirent->rec_len % 4)) {
 104                         ext2fs_free_mem(&buf);
 105                         return (EXT2_ET_DIR_CORRUPTED);
 106                 }
 107                 p += dirent->rec_len;
 108                 if (do_swap) {
 109                         dirent->inode = ext2fs_swab32(dirent->inode);
 110                         dirent->rec_len = ext2fs_swab16(dirent->rec_len);
 111                         dirent->name_len = ext2fs_swab16(dirent->name_len);
 112                 }
 113 #ifdef WORDS_BIGENDIAN
 114                 if (flags & EXT2_DIRBLOCK_V2_STRUCT)
 115                         dirent->name_len = ext2fs_swab16(dirent->name_len);
 116 #endif
 117         }
 118         retval = io_channel_write_blk(fs->io, block, 1, buf);
 119         ext2fs_free_mem(&buf);
 120         return retval;
 121 #else
 122         return io_channel_write_blk(fs->io, block, 1, (char *) inbuf);
 123 #endif
 124 }
 125
 126
 127 errcode_t ext2fs_write_dir_block(ext2_filsys fs, blk_t block,
 128                                  void *inbuf)
 129 {
 130         return ext2fs_write_dir_block2(fs, block, inbuf, 0);
 131 }
 132