lib/ext2fs/dir_iterate.c

   1 /*
   2  * dir_iterate.c --- ext2fs directory iteration operations
   3  *
   4  * Copyright (C) 1993, 1994, 1994, 1995, 1996, 1997 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 #include <string.h>
  14 #if HAVE_UNISTD_H
  15 #include <unistd.h>
  16 #endif
  17 #include <stdlib.h>
  18 #if HAVE_ERRNO_H
  19 #include <errno.h>
  20 #endif
  21
  22 #include <linux/ext2_fs.h>
  23
  24 #include "ext2fsP.h"
  25
  26 errcode_t ext2fs_dir_iterate(ext2_filsys fs,
  27                              ino_t dir,
  28                              int flags,
  29                              char *block_buf,
  30                              int (*func)(struct ext2_dir_entry *dirent,
  31                                          int    offset,
  32                                          int    blocksize,
  33                                          char   *buf,
  34                                          void   *private),
  35                              void *private)
  36 {
  37         struct          dir_context     ctx;
  38         errcode_t       retval;
  39
  40         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
  41
  42         retval = ext2fs_check_directory(fs, dir);
  43         if (retval)
  44                 return retval;
  45
  46         ctx.dir = dir;
  47         ctx.flags = flags;
  48         if (block_buf)
  49                 ctx.buf = block_buf;
  50         else {
  51                 retval = ext2fs_get_mem(fs->blocksize, (void **) &ctx.buf);
  52                 if (retval)
  53                         return retval;
  54         }
  55         ctx.func = func;
  56         ctx.func2 = 0;
  57         ctx.private = private;
  58         ctx.errcode = 0;
  59         retval = ext2fs_block_iterate(fs, dir, 0, 0,
  60                                       ext2fs_process_dir_block, &ctx);
  61         if (!block_buf)
  62                 ext2fs_free_mem((void **) &ctx.buf);
  63         if (retval)
  64                 return retval;
  65         return ctx.errcode;
  66 }
  67
  68 /*
  69  * Helper function which is private to this module.  Used by
  70  * ext2fs_dir_iterate() and ext2fs_dblist_dir_iterate()
  71  */
  72 extern int ext2fs_process_dir_block(ext2_filsys         fs,
  73                                     blk_t               *blocknr,
  74                                     int         blockcnt,
  75                                     void                *private)
  76 {
  77         struct dir_context *ctx = (struct dir_context *) private;
  78         int             offset = 0;
  79         int             ret = 0;
  80         int             changed = 0;
  81         int             do_abort = 0;
  82         int             entry;
  83         struct ext2_dir_entry *dirent;
  84
  85         if (blockcnt < 0)
  86                 return 0;
  87
  88         ctx->errcode = ext2fs_read_dir_block(fs, *blocknr, ctx->buf);
  89         if (ctx->errcode)
  90                 return BLOCK_ABORT;
  91
  92         entry = blockcnt ? DIRENT_OTHER_FILE : DIRENT_DOT_FILE;
  93
  94         while (offset < fs->blocksize) {
  95                 dirent = (struct ext2_dir_entry *) (ctx->buf + offset);
  96                 if (!dirent->inode &&
  97                     !(ctx->flags & DIRENT_FLAG_INCLUDE_EMPTY))
  98                         goto next;
  99
 100                 if (ctx->func)
 101                         ret = (ctx->func)(dirent, offset, fs->blocksize,
 102                                           ctx->buf, ctx->private);
 103                 else if (ctx->func2) {
 104                         ret = (ctx->func2)(ctx->dir, entry, dirent, offset,
 105                                            fs->blocksize, ctx->buf,
 106                                            ctx->private);
 107                         if (entry < DIRENT_OTHER_FILE)
 108                                 entry++;
 109                 }
 110
 111                 if (ret & DIRENT_CHANGED)
 112                         changed++;
 113                 if (ret & DIRENT_ABORT) {
 114                         do_abort++;
 115                         break;
 116                 }
 117 next:
 118                 if (((offset + dirent->rec_len) > fs->blocksize) ||
 119                     (dirent->rec_len < 8) ||
 120                     ((dirent->name_len+8) > dirent->rec_len)) {
 121                         ctx->errcode = EXT2_ET_DIR_CORRUPTED;
 122                         return BLOCK_ABORT;
 123                 }
 124                 offset += dirent->rec_len;
 125         }
 126
 127         if (changed) {
 128                 ctx->errcode = ext2fs_write_dir_block(fs, *blocknr, ctx->buf);
 129                 if (ctx->errcode)
 130                         return BLOCK_ABORT;
 131         }
 132         if (do_abort)
 133                 return BLOCK_ABORT;
 134         return 0;
 135 }
 136