fs/zfs_lzjb.c

   1 /*
   2  *  GRUB  --  GRand Unified Bootloader
   3  *  Copyright (C) 1999,2000,2001,2002,2003,2004  Free Software Foundation, Inc.
   4  *
   5  *  This program is free software; you can redistribute it and/or modify
   6  *  it under the terms of the GNU General Public License as published by
   7  *  the Free Software Foundation; either version 2 of the License, or
   8  *  (at your option) any later version.
   9  *
  10  *  This program is distributed in the hope that it will be useful,
  11  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  *  GNU General Public License for more details.
  14  *
  15  *  You should have received a copy of the GNU General Public License
  16  *  along with this program; if not, write to the Free Software
  17  *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  18  */
  19 /*
  20  * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
  21  * Use is subject to license terms.
  22  */
  23
  24
  25 #include <grub/err.h>
  26 #include <grub/file.h>
  27 #include <grub/mm.h>
  28 #include <grub/misc.h>
  29 #include <grub/disk.h>
  30 #include <grub/dl.h>
  31 #include <grub/types.h>
  32 #include <grub/zfs/zfs.h>
  33 #include <grub/zfs/zio.h>
  34 #include <grub/zfs/dnode.h>
  35 #include <grub/zfs/uberblock_impl.h>
  36 #include <grub/zfs/vdev_impl.h>
  37 #include <grub/zfs/zio_checksum.h>
  38 #include <grub/zfs/zap_impl.h>
  39 #include <grub/zfs/zap_leaf.h>
  40 #include <grub/zfs/zfs_znode.h>
  41 #include <grub/zfs/dmu.h>
  42 #include <grub/zfs/dmu_objset.h>
  43 #include <grub/zfs/dsl_dir.h>
  44 #include <grub/zfs/dsl_dataset.h>
  45
  46 #define MATCH_BITS      6
  47 #define MATCH_MIN       3
  48 #define OFFSET_MASK     ((1 << (16 - MATCH_BITS)) - 1)
  49
  50 /*
  51  * Decompression Entry - lzjb
  52  */
  53 #ifndef NBBY
  54 #define NBBY    8
  55 #endif
  56
  57 grub_err_t
  58 lzjb_decompress (void *s_start, void *d_start, grub_size_t s_len,
  59                  grub_size_t d_len)
  60 {
  61   grub_uint8_t *src = s_start;
  62   grub_uint8_t *dst = d_start;
  63   grub_uint8_t *d_end = (grub_uint8_t *) d_start + d_len;
  64   grub_uint8_t *s_end = (grub_uint8_t *) s_start + s_len;
  65   grub_uint8_t *cpy, copymap;
  66   int copymask = 1 << (NBBY - 1);
  67
  68   while (dst < d_end && src < s_end)
  69     {
  70       if ((copymask <<= 1) == (1 << NBBY))
  71         {
  72           copymask = 1;
  73           copymap = *src++;
  74         }
  75       if (src >= s_end)
  76         return grub_error (GRUB_ERR_BAD_FS, "lzjb decompression failed");
  77       if (copymap & copymask)
  78         {
  79           int mlen = (src[0] >> (NBBY - MATCH_BITS)) + MATCH_MIN;
  80           int offset = ((src[0] << NBBY) | src[1]) & OFFSET_MASK;
  81           src += 2;
  82           cpy = dst - offset;
  83           if (src > s_end || cpy < (grub_uint8_t *) d_start)
  84             return grub_error (GRUB_ERR_BAD_FS, "lzjb decompression failed");
  85           while (--mlen >= 0 && dst < d_end)
  86             *dst++ = *cpy++;
  87         }
  88       else
  89         *dst++ = *src++;
  90     }
  91   if (dst < d_end)
  92     return grub_error (GRUB_ERR_BAD_FS, "lzjb decompression failed");
  93   return GRUB_ERR_NONE;
  94 }