sys/ufs/lfs/lfs_cksum.c

   1 /*      $NetBSD: lfs_cksum.c,v 1.27 2008/04/28 20:24:11 martin Exp $    */
   2
   3 /*-
   4  * Copyright (c) 1999, 2000, 2001, 2002 The NetBSD Foundation, Inc.
   5  * All rights reserved.
   6  *
   7  * This code is derived from software contributed to The NetBSD Foundation
   8  * by Konrad E. Schroder <perseant@hhhh.org>.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
  20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
  23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  29  * POSSIBILITY OF SUCH DAMAGE.
  30  */
  31 /*-
  32  * Copyright (c) 1991, 1993
  33  *      The Regents of the University of California.  All rights reserved.
  34  *
  35  * Redistribution and use in source and binary forms, with or without
  36  * modification, are permitted provided that the following conditions
  37  * are met:
  38  * 1. Redistributions of source code must retain the above copyright
  39  *    notice, this list of conditions and the following disclaimer.
  40  * 2. Redistributions in binary form must reproduce the above copyright
  41  *    notice, this list of conditions and the following disclaimer in the
  42  *    documentation and/or other materials provided with the distribution.
  43  * 3. Neither the name of the University nor the names of its contributors
  44  *    may be used to endorse or promote products derived from this software
  45  *    without specific prior written permission.
  46  *
  47  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  48  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  49  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  50  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  51  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  52  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  53  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  54  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  55  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  56  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  57  * SUCH DAMAGE.
  58  *
  59  *      @(#)lfs_cksum.c 8.2 (Berkeley) 10/9/94
  60  */
  61
  62 #include <sys/cdefs.h>
  63 __KERNEL_RCSID(0, "$NetBSD: lfs_cksum.c,v 1.27 2008/04/28 20:24:11 martin Exp $");
  64
  65 #include <sys/param.h>
  66 #ifdef _KERNEL
  67 # include <sys/systm.h>
  68 # include <sys/lock.h>
  69 #else
  70 # include <stddef.h>
  71 #endif
  72 #include <sys/mount.h>
  73 #include <ufs/ufs/inode.h>
  74 #include <ufs/lfs/lfs.h>
  75 #include <ufs/lfs/lfs_extern.h>
  76
  77 /*
  78  * Simple, general purpose, fast checksum.  Data must be short-aligned.
  79  * Returns a u_long in case we ever want to do something more rigorous.
  80  *
  81  * XXX
  82  * Use the TCP/IP checksum instead.
  83  */
  84 u_int32_t
  85 lfs_cksum_part(void *str, size_t len, u_int32_t sum)
  86 {
  87
  88         len &= ~(sizeof(u_int16_t) - 1);
  89         for (; len; len -= sizeof(u_int16_t)) {
  90                 sum ^= *(u_int16_t *)str;
  91                 str = (void *)((u_int16_t *)str + 1);
  92         }
  93         return (sum);
  94 }
  95
  96 u_int32_t
  97 cksum(void *str, size_t len)
  98 {
  99
 100         return lfs_cksum_fold(lfs_cksum_part(str, len, 0));
 101 }
 102
 103 u_int32_t
 104 lfs_sb_cksum(struct dlfs *fs)
 105 {
 106         size_t size;
 107
 108         size = (size_t)offsetof(struct dlfs, dlfs_cksum);
 109         return cksum(fs, size);
 110 }