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ffs_sb_swap() fixes: 

- calculate the offset and length of the postbl before byteswapping.
  problem noted by der Mouse.
- use offsetof() to determine # of fields to calculate in initial
  loop, rather than hard-coding in `52 fields'
- improve comments.
This commit is contained in:
lukem 2001-10-29 11:26:35 +00:00
parent ae963680ea
commit 80ac606906
1 changed files with 19 additions and 12 deletions
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31
sys/ufs/ffs/ffs_bswap.c
View File

@ -1,4 +1,4 @@
/* $NetBSD: ffs_bswap.c,v 1.13 2001/09/06 02:16:02 lukem Exp $ */
/* $NetBSD: ffs_bswap.c,v 1.14 2001/10/29 11:26:35 lukem Exp $ */
/*
* Copyright (c) 1998 Manuel Bouyer.
@ -43,6 +43,7 @@
#include <ufs/ffs/ffs_extern.h>
#if !defined(_KERNEL)
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
@ -66,19 +67,32 @@ ffs_sb_swap(struct fs *o, struct fs *n)
}
postbloff = ufs_rw32(o->fs_postbloff, needswap);
postblfmt = ufs_rw32(o->fs_postblformat, needswap);
/* compute these before swapping, in case o == n */
o16 = (postblfmt == FS_42POSTBLFMT) ? o->fs_opostbl[0] :
(int16_t *)((u_int8_t *)o + postbloff);
n16 = (postblfmt == FS_42POSTBLFMT) ? n->fs_opostbl[0] :
(int16_t *)((u_int8_t *)n + postbloff);
len = postblfmt == FS_42POSTBLFMT ?
sizeof(o->fs_opostbl) / sizeof(o->fs_opostbl[0][0]) :
ufs_rw32(o->fs_cpc, needswap) * ufs_rw32(o->fs_nrpos, needswap);
/*
* In order to avoid a lot of lines, as the first 52 fields of
* the superblock are u_int32_t, we loop here to convert it.
* In order to avoid a lot of lines, as the first N fields (52)
* of the superblock up to fs_fmod are u_int32_t, we just loop
* here to convert them.
*/
o32 = (u_int32_t *)o;
n32 = (u_int32_t *)n;
for (i = 0; i < 52; i++)
for (i = 0; i < offsetof(struct fs, fs_fmod) / sizeof(u_int32_t); i++)
n32[i] = bswap32(o32[i]);
/* fs_cgrotor is now unused */
n->fs_cpc = bswap32(o->fs_cpc);
/* fs_opostbl - may be done below */
/* fs_snapinum[20] - ignore for now */
n->fs_avgfilesize = bswap32(o->fs_avgfilesize);
n->fs_avgfpdir = bswap32(o->fs_avgfpdir);
/* fs_sparecon[28] - ignore for now */
n->fs_contigsumsize = bswap32(o->fs_contigsumsize);
n->fs_maxsymlinklen = bswap32(o->fs_maxsymlinklen);
n->fs_inodefmt = bswap32(o->fs_inodefmt);
@ -91,14 +105,7 @@ ffs_sb_swap(struct fs *o, struct fs *n)
n->fs_postbloff = bswap32(o->fs_postbloff);
n->fs_rotbloff = bswap32(o->fs_rotbloff);
n->fs_magic = bswap32(o->fs_magic);
/* byteswap the postbl */
o16 = (postblfmt == FS_42POSTBLFMT) ? o->fs_opostbl[0] :
(int16_t *)((u_int8_t *)o + postbloff);
n16 = (postblfmt == FS_42POSTBLFMT) ? n->fs_opostbl[0] :
(int16_t *)((u_int8_t *)n + postbloff);
len = postblfmt == FS_42POSTBLFMT ?
128 /* fs_opostbl[16][8] */ :
ufs_rw32(o->fs_cpc, needswap) * ufs_rw32(o->fs_nrpos, needswap);
/* byteswap the postbl */
for (i = 0; i < len; i++)
n16[i] = bswap16(o16[i]);
}