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221 lines
5.2 KiB
C
221 lines
5.2 KiB
C
/* vi: set sw=4 ts=4: */
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/*
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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 Public
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* License.
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* %End-Header%
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*/
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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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/*
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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(char *buf, int offset, int final_offset)
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{
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struct ext2_dir_entry *dirent;
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while (offset < final_offset) {
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dirent = (struct ext2_dir_entry *)(buf + offset);
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offset += dirent->rec_len;
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if ((dirent->rec_len < 8) ||
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((dirent->rec_len % 4) != 0) ||
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(((dirent->name_len & 0xFF)+8) > dirent->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_iterate2(fs, dir, 0, 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)
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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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extern 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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blk_t *blocknr,
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e2_blkcnt_t blockcnt,
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blk_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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int entry, size;
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struct ext2_dir_entry *dirent;
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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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ctx->errcode = ext2fs_read_dir_block(fs, *blocknr, ctx->buf);
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if (ctx->errcode)
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return BLOCK_ABORT;
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while (offset < fs->blocksize) {
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dirent = (struct ext2_dir_entry *) (ctx->buf + offset);
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if (((offset + dirent->rec_len) > fs->blocksize) ||
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(dirent->rec_len < 8) ||
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((dirent->rec_len % 4) != 0) ||
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(((dirent->name_len & 0xFF)+8) > dirent->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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!(ctx->flags & DIRENT_FLAG_INCLUDE_EMPTY))
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goto next;
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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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fs->blocksize, 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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changed++;
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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 += dirent->rec_len;
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if (ctx->flags & DIRENT_FLAG_INCLUDE_REMOVED) {
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size = ((dirent->name_len & 0xFF) + 11) & ~3;
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if (dirent->rec_len != size) {
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unsigned int final_offset;
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final_offset = offset + dirent->rec_len;
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offset += size;
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while (offset < final_offset &&
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!ext2fs_validate_entry(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 += dirent->rec_len;
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}
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if (changed) {
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ctx->errcode = ext2fs_write_dir_block(fs, *blocknr, ctx->buf);
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if (ctx->errcode)
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return BLOCK_ABORT;
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}
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if (do_abort)
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return BLOCK_ABORT;
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return 0;
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}
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