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312 lines
7.5 KiB
312 lines
7.5 KiB
/*
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* dir_iterate.c --- ext2fs directory iteration operations
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*
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* Copyright (C) 1993, 1994, 1994, 1995, 1996, 1997 Theodore Ts'o.
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*
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* %Begin-Header%
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* This file may be redistributed under the terms of the GNU Library
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* General Public License, version 2.
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* %End-Header%
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*/
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#include "config.h"
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#include <stdio.h>
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#include <string.h>
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#if HAVE_UNISTD_H
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#include <unistd.h>
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#endif
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#if HAVE_ERRNO_H
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#include <errno.h>
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#endif
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#include "ext2_fs.h"
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#include "ext2fsP.h"
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#define EXT4_MAX_REC_LEN ((1<<16)-1)
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errcode_t ext2fs_get_rec_len(ext2_filsys fs,
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struct ext2_dir_entry *dirent,
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unsigned int *rec_len)
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{
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unsigned int len = dirent->rec_len;
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if (fs->blocksize < 65536)
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*rec_len = len;
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else if (len == EXT4_MAX_REC_LEN || len == 0)
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*rec_len = fs->blocksize;
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else
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*rec_len = (len & 65532) | ((len & 3) << 16);
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return 0;
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}
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errcode_t ext2fs_set_rec_len(ext2_filsys fs,
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unsigned int len,
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struct ext2_dir_entry *dirent)
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{
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if ((len > fs->blocksize) || (fs->blocksize > (1 << 18)) || (len & 3))
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return EINVAL;
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if (len < 65536) {
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dirent->rec_len = len;
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return 0;
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}
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if (len == fs->blocksize) {
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if (fs->blocksize == 65536)
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dirent->rec_len = EXT4_MAX_REC_LEN;
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else
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dirent->rec_len = 0;
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} else
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dirent->rec_len = (len & 65532) | ((len >> 16) & 3);
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return 0;
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}
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/*
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* This function checks to see whether or not a potential deleted
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* directory entry looks valid. What we do is check the deleted entry
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* and each successive entry to make sure that they all look valid and
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* that the last deleted entry ends at the beginning of the next
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* undeleted entry. Returns 1 if the deleted entry looks valid, zero
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* if not valid.
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*/
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static int ext2fs_validate_entry(ext2_filsys fs, char *buf,
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unsigned int offset,
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unsigned int final_offset)
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{
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struct ext2_dir_entry *dirent;
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unsigned int rec_len;
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#define DIRENT_MIN_LENGTH 12
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while ((offset < final_offset) &&
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(offset <= fs->blocksize - DIRENT_MIN_LENGTH)) {
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dirent = (struct ext2_dir_entry *)(buf + offset);
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if (ext2fs_get_rec_len(fs, dirent, &rec_len))
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return 0;
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offset += rec_len;
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if ((rec_len < 8) ||
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((rec_len % 4) != 0) ||
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((ext2fs_dirent_name_len(dirent)+8) > (int) rec_len))
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return 0;
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}
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return (offset == final_offset);
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}
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errcode_t ext2fs_dir_iterate2(ext2_filsys fs,
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ext2_ino_t dir,
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int flags,
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char *block_buf,
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int (*func)(ext2_ino_t dir,
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int entry,
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struct ext2_dir_entry *dirent,
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int offset,
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int blocksize,
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char *buf,
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void *priv_data),
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void *priv_data)
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{
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struct dir_context ctx;
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errcode_t retval;
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EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
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retval = ext2fs_check_directory(fs, dir);
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if (retval)
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return retval;
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ctx.dir = dir;
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ctx.flags = flags;
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if (block_buf)
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ctx.buf = block_buf;
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else {
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retval = ext2fs_get_mem(fs->blocksize, &ctx.buf);
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if (retval)
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return retval;
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}
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ctx.func = func;
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ctx.priv_data = priv_data;
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ctx.errcode = 0;
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retval = ext2fs_block_iterate3(fs, dir, BLOCK_FLAG_READ_ONLY, 0,
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ext2fs_process_dir_block, &ctx);
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if (!block_buf)
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ext2fs_free_mem(&ctx.buf);
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if (retval == EXT2_ET_INLINE_DATA_CANT_ITERATE) {
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(void) ext2fs_inline_data_dir_iterate(fs, dir, &ctx);
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retval = 0;
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}
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if (retval)
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return retval;
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return ctx.errcode;
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}
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struct xlate {
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int (*func)(struct ext2_dir_entry *dirent,
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int offset,
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int blocksize,
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char *buf,
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void *priv_data);
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void *real_private;
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};
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static int xlate_func(ext2_ino_t dir EXT2FS_ATTR((unused)),
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int entry EXT2FS_ATTR((unused)),
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struct ext2_dir_entry *dirent, int offset,
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int blocksize, char *buf, void *priv_data)
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{
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struct xlate *xl = (struct xlate *) priv_data;
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return (*xl->func)(dirent, offset, blocksize, buf, xl->real_private);
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}
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errcode_t ext2fs_dir_iterate(ext2_filsys fs,
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ext2_ino_t dir,
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int flags,
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char *block_buf,
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int (*func)(struct ext2_dir_entry *dirent,
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int offset,
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int blocksize,
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char *buf,
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void *priv_data),
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void *priv_data)
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{
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struct xlate xl;
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xl.real_private = priv_data;
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xl.func = func;
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return ext2fs_dir_iterate2(fs, dir, flags, block_buf,
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xlate_func, &xl);
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}
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/*
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* Helper function which is private to this module. Used by
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* ext2fs_dir_iterate() and ext2fs_dblist_dir_iterate()
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*/
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int ext2fs_process_dir_block(ext2_filsys fs,
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blk64_t *blocknr,
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e2_blkcnt_t blockcnt,
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blk64_t ref_block EXT2FS_ATTR((unused)),
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int ref_offset EXT2FS_ATTR((unused)),
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void *priv_data)
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{
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struct dir_context *ctx = (struct dir_context *) priv_data;
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unsigned int offset = 0;
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unsigned int next_real_entry = 0;
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int ret = 0;
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int changed = 0;
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int do_abort = 0;
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unsigned int rec_len, size, buflen;
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int entry;
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struct ext2_dir_entry *dirent;
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int csum_size = 0;
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int inline_data;
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errcode_t retval = 0;
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if (blockcnt < 0)
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return 0;
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entry = blockcnt ? DIRENT_OTHER_FILE : DIRENT_DOT_FILE;
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/* If a dir has inline data, we don't need to read block */
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inline_data = !!(ctx->flags & DIRENT_FLAG_INCLUDE_INLINE_DATA);
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if (!inline_data) {
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ctx->errcode = ext2fs_read_dir_block4(fs, *blocknr, ctx->buf, 0,
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ctx->dir);
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if (ctx->errcode)
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return BLOCK_ABORT;
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/* If we handle a normal dir, we traverse the entire block */
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buflen = fs->blocksize;
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} else {
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buflen = ctx->buflen;
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}
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if (ext2fs_has_feature_metadata_csum(fs->super))
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csum_size = sizeof(struct ext2_dir_entry_tail);
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while (offset < buflen - 8) {
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dirent = (struct ext2_dir_entry *) (ctx->buf + offset);
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if (ext2fs_get_rec_len(fs, dirent, &rec_len))
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return BLOCK_ABORT;
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if (((offset + rec_len) > buflen) ||
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(rec_len < 8) ||
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((rec_len % 4) != 0) ||
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((ext2fs_dirent_name_len(dirent)+8) > (int) rec_len)) {
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ctx->errcode = EXT2_ET_DIR_CORRUPTED;
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return BLOCK_ABORT;
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}
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if (!dirent->inode) {
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/*
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* We just need to check metadata_csum when this
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* dir hasn't inline data. That means that 'buflen'
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* should be blocksize.
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*/
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if (!inline_data &&
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(offset == buflen - csum_size) &&
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(dirent->rec_len == csum_size) &&
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(dirent->name_len == EXT2_DIR_NAME_LEN_CSUM)) {
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if (!(ctx->flags & DIRENT_FLAG_INCLUDE_CSUM))
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goto next;
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entry = DIRENT_CHECKSUM;
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} else if (!(ctx->flags & DIRENT_FLAG_INCLUDE_EMPTY))
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goto next;
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}
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ret = (ctx->func)(ctx->dir,
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(next_real_entry > offset) ?
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DIRENT_DELETED_FILE : entry,
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dirent, offset,
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buflen, ctx->buf,
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ctx->priv_data);
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if (entry < DIRENT_OTHER_FILE)
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entry++;
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if (ret & DIRENT_CHANGED) {
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if (ext2fs_get_rec_len(fs, dirent, &rec_len))
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return BLOCK_ABORT;
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changed++;
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}
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if (ret & DIRENT_ABORT) {
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do_abort++;
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break;
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}
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next:
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if (next_real_entry == offset)
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next_real_entry += rec_len;
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if (ctx->flags & DIRENT_FLAG_INCLUDE_REMOVED) {
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size = (ext2fs_dirent_name_len(dirent) + 11) & ~3;
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if (rec_len != size) {
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unsigned int final_offset;
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final_offset = offset + rec_len;
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offset += size;
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while (offset < final_offset &&
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!ext2fs_validate_entry(fs, ctx->buf,
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offset,
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final_offset))
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offset += 4;
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continue;
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}
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}
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offset += rec_len;
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}
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if (changed) {
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if (!inline_data) {
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ctx->errcode = ext2fs_write_dir_block4(fs, *blocknr,
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ctx->buf,
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0, ctx->dir);
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if (ctx->errcode)
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return BLOCK_ABORT;
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} else {
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/*
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* return BLOCK_INLINE_DATA_CHANGED to notify caller
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* that inline data has been changed.
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*/
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retval = BLOCK_INLINE_DATA_CHANGED;
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}
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}
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if (do_abort)
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return retval | BLOCK_ABORT;
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return retval;
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}
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