release/src/router/busybox/e2fsprogs/old_e2fsprogs/ext2fs/dirblock.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * dirblock.c --- directory block routines.
   4  *
   5  * Copyright (C) 1995, 1996 Theodore Ts'o.
   6  *
   7  * %Begin-Header%
   8  * This file may be redistributed under the terms of the GNU Public
   9  * License.
  10  * %End-Header%
  11  */
  12
  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_block2(ext2_filsys fs, blk_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 #if BB_BIG_ENDIAN
  31         unsigned int do_swap;
  32 #endif
  33
  34         retval = io_channel_read_blk(fs->io, block, 1, buf);
  35         if (retval)
  36                 return retval;
  37 #if BB_BIG_ENDIAN
  38         do_swap = (fs->flags & (EXT2_FLAG_SWAP_BYTES|
  39                                 EXT2_FLAG_SWAP_BYTES_READ)) != 0;
  40 #endif
  41         p = (char *) buf;
  42         end = (char *) buf + fs->blocksize;
  43         while (p < end-8) {
  44                 dirent = (struct ext2_dir_entry *) p;
  45 #if BB_BIG_ENDIAN
  46                 if (do_swap) {
  47                         dirent->inode = ext2fs_swab32(dirent->inode);
  48                         dirent->rec_len = ext2fs_swab16(dirent->rec_len);
  49                         dirent->name_len = ext2fs_swab16(dirent->name_len);
  50                 }
  51 #endif
  52                 name_len = dirent->name_len;
  53 #ifdef WORDS_BIGENDIAN
  54                 if (flags & EXT2_DIRBLOCK_V2_STRUCT)
  55                         dirent->name_len = ext2fs_swab16(dirent->name_len);
  56 #endif
  57                 rec_len = dirent->rec_len;
  58                 if ((rec_len < 8) || (rec_len % 4)) {
  59                         rec_len = 8;
  60                         retval = EXT2_ET_DIR_CORRUPTED;
  61                 }
  62                 if (((name_len & 0xFF) + 8) > dirent->rec_len)
  63                         retval = EXT2_ET_DIR_CORRUPTED;
  64                 p += rec_len;
  65         }
  66         return retval;
  67 }
  68
  69 errcode_t ext2fs_read_dir_block(ext2_filsys fs, blk_t block,
  70                                  void *buf)
  71 {
  72         return ext2fs_read_dir_block2(fs, block, buf, 0);
  73 }
  74
  75
  76 errcode_t ext2fs_write_dir_block2(ext2_filsys fs, blk_t block,
  77                                   void *inbuf, int flags EXT2FS_ATTR((unused)))
  78 {
  79 #if BB_BIG_ENDIAN
  80         int             do_swap = 0;
  81         errcode_t       retval;
  82         char            *p, *end;
  83         char            *buf = NULL;
  84         struct ext2_dir_entry *dirent;
  85
  86         if ((fs->flags & EXT2_FLAG_SWAP_BYTES) ||
  87             (fs->flags & EXT2_FLAG_SWAP_BYTES_WRITE))
  88                 do_swap = 1;
  89
  90 #ifndef WORDS_BIGENDIAN
  91         if (!do_swap)
  92                 return io_channel_write_blk(fs->io, block, 1, (char *) inbuf);
  93 #endif
  94
  95         retval = ext2fs_get_mem(fs->blocksize, &buf);
  96         if (retval)
  97                 return retval;
  98         memcpy(buf, inbuf, fs->blocksize);
  99         p = buf;
 100         end = buf + fs->blocksize;
 101         while (p < end) {
 102                 dirent = (struct ext2_dir_entry *) p;
 103                 if ((dirent->rec_len < 8) ||
 104                     (dirent->rec_len % 4)) {
 105                         ext2fs_free_mem(&buf);
 106                         return EXT2_ET_DIR_CORRUPTED;
 107                 }
 108                 p += dirent->rec_len;
 109                 if (do_swap) {
 110                         dirent->inode = ext2fs_swab32(dirent->inode);
 111                         dirent->rec_len = ext2fs_swab16(dirent->rec_len);
 112                         dirent->name_len = ext2fs_swab16(dirent->name_len);
 113                 }
 114 #ifdef WORDS_BIGENDIAN
 115                 if (flags & EXT2_DIRBLOCK_V2_STRUCT)
 116                         dirent->name_len = ext2fs_swab16(dirent->name_len);
 117 #endif
 118         }
 119         retval = io_channel_write_blk(fs->io, block, 1, buf);
 120         ext2fs_free_mem(&buf);
 121         return retval;
 122 #else
 123         return io_channel_write_blk(fs->io, block, 1, (char *) inbuf);
 124 #endif
 125 }
 126
 127
 128 errcode_t ext2fs_write_dir_block(ext2_filsys fs, blk_t block,
 129                                  void *inbuf)
 130 {
 131         return ext2fs_write_dir_block2(fs, block, inbuf, 0);
 132 }