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      1 /*	$NetBSD: disklabel_swap.c,v 1.1 2021/05/17 08:50:36 mrg Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1982, 1986, 1988 Regents of the University of California.
      5  * All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  * 3. Neither the name of the University nor the names of its contributors
     16  *    may be used to endorse or promote products derived from this software
     17  *    without specific prior written permission.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     29  * SUCH DAMAGE.
     30  *
     31  *	@(#)ufs_disksubr.c	7.16 (Berkeley) 5/4/91
     32  */
     33 
     34 #include <sys/cdefs.h>
     35 __KERNEL_RCSID(0, "$NetBSD: disklabel_swap.c,v 1.1 2021/05/17 08:50:36 mrg Exp $");
     36 
     37 #ifdef _KERNEL_OPT
     38 #include "opt_disklabel.h"
     39 #endif /* _KERNEL_OPT */
     40 
     41 #if defined(DISKLABEL_EI) || defined(LIBSA_DISKLABEL_EI)
     42 
     43 #include <sys/param.h>
     44 #include <sys/systm.h>
     45 #include <sys/disklabel.h>
     46 #include <sys/conf.h>
     47 #include <lib/libkern/libkern.h>
     48 
     49 /*
     50  * from sh3/disksubr.c and kern/subr_disk_mbr.c with modifications:
     51  *	- update d_checksum properly
     52  *	- replace memcpy(9) by memmove(9) as a precaution
     53  *	- avoid memmove(9) for libkern version, check if the labels
     54  *	  are the same and skip copying in-place.
     55  */
     56 void
     57 disklabel_swap(struct disklabel *nlp, struct disklabel *olp)
     58 {
     59 	int i;
     60 	uint16_t npartitions;
     61 
     62 #define	SWAP16(x)	nlp->x = bswap16(olp->x)
     63 #define	SWAP32(x)	nlp->x = bswap32(olp->x)
     64 
     65 	SWAP32(d_magic);
     66 	SWAP16(d_type);
     67 	SWAP16(d_subtype);
     68 	if (nlp != olp) {
     69 		/* Do not need to swap char strings. */
     70 		memcpy(nlp->d_typename, olp->d_typename,
     71 			sizeof(nlp->d_typename));
     72 
     73 		/*
     74 		 * XXX What should we do for d_un (an union of char and
     75 		 * pointers)?
     76 		 */
     77 		memcpy(nlp->d_packname, olp->d_packname,
     78 			sizeof(nlp->d_packname));
     79 	}
     80 
     81 	SWAP32(d_secsize);
     82 	SWAP32(d_nsectors);
     83 	SWAP32(d_ntracks);
     84 	SWAP32(d_ncylinders);
     85 	SWAP32(d_secpercyl);
     86 	SWAP32(d_secperunit);
     87 
     88 	SWAP16(d_sparespertrack);
     89 	SWAP16(d_sparespercyl);
     90 
     91 	SWAP32(d_acylinders);
     92 
     93 	SWAP16(d_rpm);
     94 	SWAP16(d_interleave);
     95 	SWAP16(d_trackskew);
     96 	SWAP16(d_cylskew);
     97 	SWAP32(d_headswitch);
     98 	SWAP32(d_trkseek);
     99 	SWAP32(d_flags);
    100 	for (i = 0; i < NDDATA; i++)
    101 		SWAP32(d_drivedata[i]);
    102 	for (i = 0; i < NSPARE; i++)
    103 		SWAP32(d_spare[i]);
    104 	SWAP32(d_magic2);
    105 	/* d_checksum is updated later. */
    106 
    107 	SWAP16(d_npartitions);
    108 	SWAP32(d_bbsize);
    109 	SWAP32(d_sbsize);
    110 	for (i = 0; i < MAXPARTITIONS; i++) {
    111 		SWAP32(d_partitions[i].p_size);
    112 		SWAP32(d_partitions[i].p_offset);
    113 		SWAP32(d_partitions[i].p_fsize);
    114 		/* p_fstype and p_frag is uint8_t, so no need to swap. */
    115 		nlp->d_partitions[i].p_fstype = olp->d_partitions[i].p_fstype;
    116 		nlp->d_partitions[i].p_frag = olp->d_partitions[i].p_frag;
    117 		SWAP16(d_partitions[i].p_cpg);
    118 	}
    119 
    120 #undef SWAP16
    121 #undef SWAP32
    122 
    123 	/* Update checksum in the target endian. */
    124 	nlp->d_checksum = 0;
    125 	npartitions = nlp->d_magic == DISKMAGIC ?
    126 	    nlp->d_npartitions : olp->d_npartitions;
    127 	/*
    128 	 * npartitions can be larger than MAXPARTITIONS when the label was not
    129 	 * validated by setdisklabel. If so, the label is intentionally(?)
    130 	 * corrupted and checksum should be meaningless.
    131 	 */
    132 	if (npartitions <= MAXPARTITIONS)
    133 		nlp->d_checksum = dkcksum_sized(nlp, npartitions);
    134 }
    135 #endif /* DISKLABEL_EI || LIBSA_DISKLABEL_EI */
    136