570 lines
15 KiB
C
570 lines
15 KiB
C
/* $NetBSD: subr_disk_mbr.c,v 1.1 2003/07/07 13:28:48 dsl Exp $ */
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/*
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* Copyright (c) 1982, 1986, 1988 Regents of the University of California.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @(#)ufs_disksubr.c 7.16 (Berkeley) 5/4/91
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*/
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/*
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* Code to find a NetBSD label on a disk that contains an i386 style MBR.
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* The first NetBSD label found in the 2nd sector of a NetBSD partition
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* is used. If there isn't a NetBSD partition then a label is faked up
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* from the MBR.
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*
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* If there isn't a disklabel or anything in the MBR then partition a
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* is set to cover the whole disk.
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* Useful for files that contain single filesystems (etc).
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*
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* This code will read host endian netbsd labels from little endian MBR.
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*
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* Based on the i386 disksubr.c
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*
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* XXX There are potential problems writing labels to disks where there
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* is only space for 8 netbsd partitions but this code has been compiled
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* with MAXPARTITIONS=16.
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*/
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: subr_disk_mbr.c,v 1.1 2003/07/07 13:28:48 dsl Exp $");
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/buf.h>
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#include <sys/disklabel.h>
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#include <sys/disk.h>
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#include <sys/syslog.h>
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#include "opt_mbr.h"
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#define MBR_LABELSECTOR 1
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#define SCAN_CONTINUE 0
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#define SCAN_FOUND 1
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#define SCAN_ERROR 2
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typedef struct mbr_args {
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struct disklabel *lp;
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void (*strat)(struct buf *);
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struct buf *bp;
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const char *msg;
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int error;
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} mbr_args_t;
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#define READ_LABEL 1
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#define WRITE_LABEL 2
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static int validate_label(mbr_args_t *, uint, int);
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static int look_netbsd_part(mbr_args_t *, mbr_partition_t *, int, uint);
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static int write_netbsd_label(mbr_args_t *, mbr_partition_t *, int, uint);
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static int
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read_sector(mbr_args_t *a, uint sector)
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{
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struct buf *bp = a->bp;
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int error;
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bp->b_blkno = sector;
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bp->b_bcount = a->lp->d_secsize;
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bp->b_flags = (bp->b_flags & ~(B_WRITE | B_DONE)) | B_READ;
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bp->b_cylinder = sector / a->lp->d_secpercyl;
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(*a->strat)(bp);
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error = biowait(bp);
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if (error != 0)
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a->error = error;
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return error;
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}
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/*
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* Scan MBR for partitions, call 'action' routine for each.
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*/
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static int
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scan_mbr(mbr_args_t *a, int (*actn)(mbr_args_t *, mbr_partition_t *, int, uint))
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{
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mbr_partition_t ptns[NMBRPART];
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mbr_partition_t *dp;
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mbr_sector_t *mbr;
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uint ext_base, this_ext, next_ext;
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int rval;
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int i;
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#ifdef COMPAT_386BSD_MBRPART
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int dp_386bsd = -1;
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#endif
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ext_base = 0;
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this_ext = 0;
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for (;;) {
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if (read_sector(a, this_ext)) {
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a->msg = "dos partition I/O error";
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return SCAN_ERROR;
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}
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/* Note: Magic number is little-endian. */
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mbr = (void *)a->bp->b_data;
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if (mbr->mbr_signature != htole16(MBR_MAGIC)) {
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/* Don't set an error message here.... */
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return SCAN_ERROR;
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}
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/* Copy data out of buffer so action can use bp */
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memcpy(ptns, &mbr->mbr_parts, sizeof ptns);
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/* look for NetBSD partition */
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next_ext = 0;
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dp = ptns;
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for (i = 0; i < NMBRPART; i++, dp++) {
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if (dp->mbrp_typ == 0)
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continue;
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if (MBR_IS_EXTENDED(dp->mbrp_typ)) {
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next_ext = le32toh(dp->mbrp_start);
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continue;
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}
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#ifdef COMPAT_386BSD_MBRPART
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if (dp->mbrp_typ == MBR_PTYPE_386BSD) {
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/*
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* If more than one matches, take last,
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* as NetBSD install tool does.
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*/
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if (this_ext == 0)
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dp_386bsd = i;
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continue;
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}
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#endif
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rval = (*actn)(a, dp, i, this_ext);
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if (rval != SCAN_CONTINUE)
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return rval;
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}
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if (next_ext == 0)
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break;
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if (ext_base == 0) {
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ext_base = next_ext;
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next_ext = 0;
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}
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next_ext += ext_base;
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if (next_ext <= this_ext)
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break;
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this_ext = next_ext;
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}
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#ifdef COMPAT_386BSD_MBRPART
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if (this_ext == 0 && dp_386bsd != -1)
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return (*actn)(a, &ptns[dp_386bsd], dp_386bsd, 0);
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#endif
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return SCAN_CONTINUE;
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}
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/*
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* Attempt to read a disk label from a device
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* using the indicated strategy routine.
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* The label must be partly set up before this:
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* secpercyl, secsize and anything required for a block i/o read
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* operation in the driver's strategy/start routines
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* must be filled in before calling us.
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*
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* If dos partition table requested, attempt to load it and
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* find disklabel inside a DOS partition. Also, if bad block
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* table needed, attempt to extract it as well. Return buffer
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* for use in signalling errors if requested.
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*
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* Returns null on success and an error string on failure.
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*/
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const char *
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readdisklabel(dev, strat, lp, osdep)
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dev_t dev;
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void (*strat)(struct buf *);
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struct disklabel *lp;
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struct cpu_disklabel *osdep;
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{
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struct dkbad *bdp;
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int rval;
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int i;
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mbr_args_t a;
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a.lp = lp;
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a.strat = strat;
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a.msg = NULL;
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a.error = 0;
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/* minimal requirements for architypal disk label */
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if (lp->d_secsize == 0)
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lp->d_secsize = DEV_BSIZE;
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if (lp->d_secperunit == 0)
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lp->d_secperunit = 0x1fffffff;
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lp->d_npartitions = RAW_PART + 1;
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for (i = 0; i < RAW_PART; i++) {
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lp->d_partitions[i].p_size = 0;
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lp->d_partitions[i].p_offset = 0;
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}
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if (lp->d_partitions[RAW_PART].p_size == 0)
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lp->d_partitions[RAW_PART].p_size = 0x1fffffff;
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lp->d_partitions[RAW_PART].p_offset = 0;
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/*
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* Set partition 'a' to be the whole disk.
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* Cleared if we find an mbr or a netbsd label.
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*/
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lp->d_partitions[0].p_size = lp->d_partitions[RAW_PART].p_size;
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lp->d_partitions[0].p_fstype = FS_BSDFFS;
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/* get a buffer and initialize it */
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a.bp = geteblk((int)lp->d_secsize);
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a.bp->b_dev = dev;
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if (osdep)
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/*
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* Scan mbr searching for netbsd partition and saving
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* bios partition information to use if the netbsd one
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* is absent.
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*/
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rval = scan_mbr(&a, look_netbsd_part);
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else
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rval = SCAN_CONTINUE;
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if (rval == SCAN_CONTINUE || (rval == SCAN_ERROR && a.msg == NULL)) {
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/* Look at start of disk */
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rval = validate_label(&a, LABELSECTOR, READ_LABEL);
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if (LABELSECTOR != 0 && rval == SCAN_CONTINUE)
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rval = validate_label(&a, 0, READ_LABEL);
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}
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/* Obtain bad sector table if requested and present */
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if (rval == SCAN_FOUND && osdep && (lp->d_flags & D_BADSECT)) {
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struct dkbad *db;
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int blkno;
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bdp = &osdep->bad;
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i = 0;
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rval = SCAN_ERROR;
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do {
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/* read a bad sector table */
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blkno = lp->d_secperunit - lp->d_nsectors + i;
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if (lp->d_secsize > DEV_BSIZE)
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blkno *= lp->d_secsize / DEV_BSIZE;
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else
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blkno /= DEV_BSIZE / lp->d_secsize;
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/* if successful, validate, otherwise try another */
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if (read_sector(&a, blkno)) {
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a.msg = "bad sector table I/O error";
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continue;
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}
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db = (struct dkbad *)(a.bp->b_data);
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#define DKBAD_MAGIC 0x4321
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if (db->bt_mbz != 0 || db->bt_flag != DKBAD_MAGIC) {
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a.msg = "bad sector table corrupted";
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continue;
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}
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rval = SCAN_FOUND;
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*bdp = *db;
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break;
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} while ((a.bp->b_flags & B_ERROR) && (i += 2) < 10 &&
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i < lp->d_nsectors);
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}
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brelse(a.bp);
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if (rval != SCAN_ERROR)
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return NULL;
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return a.msg;
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}
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static int
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look_netbsd_part(mbr_args_t *a, mbr_partition_t *dp, int slot, uint ext_base)
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{
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struct partition *pp;
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int ptn_base = ext_base + le32toh(dp->mbrp_start);
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int rval;
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if (
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#ifdef COMPAT_386BSD_MBRPART
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dp->mbrp_typ == MBR_PTYPE_386BSD ||
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#endif
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dp->mbrp_typ == MBR_PTYPE_NETBSD) {
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rval = validate_label(a, ptn_base + MBR_LABELSECTOR, READ_LABEL);
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/* Put actual location where we found the label into ptn 2 */
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if (RAW_PART != 2 && (rval == SCAN_FOUND ||
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a->lp->d_partitions[2].p_size == 0)) {
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a->lp->d_partitions[2].p_size = le32toh(dp->mbrp_size);
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a->lp->d_partitions[2].p_offset = ptn_base;
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}
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/* If we got a netbsd label look no further */
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if (rval == SCAN_FOUND)
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return rval;
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}
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/* Install main partitions into e..h and extended into i+ */
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if (ext_base == 0)
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slot += 4;
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else {
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slot = 4 + NMBRPART;
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pp = &a->lp->d_partitions[slot];
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for (; slot < MAXPARTITIONS; pp++, slot++) {
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/* This gets called twice - avoid duplicates */
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if (pp->p_offset == ptn_base &&
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pp->p_size == le32toh(dp->mbrp_size))
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break;
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if (pp->p_size == 0)
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break;
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}
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}
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if (slot < MAXPARTITIONS) {
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/* Stop 'a' being the entire disk */
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a->lp->d_partitions[0].p_size = 0;
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a->lp->d_partitions[0].p_fstype = 0;
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/* save partition info */
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pp = &a->lp->d_partitions[slot];
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pp->p_offset = ptn_base;
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pp->p_size = le32toh(dp->mbrp_size);
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pp->p_fstype = xlat_mbr_fstype(dp->mbrp_typ);
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if (slot >= a->lp->d_npartitions)
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a->lp->d_npartitions = slot + 1;
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}
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return SCAN_CONTINUE;
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}
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static int
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validate_label(mbr_args_t *a, uint label_sector, int action)
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{
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struct disklabel *dlp, *dlp_lim;
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int error;
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/* Next, dig out disk label */
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if (read_sector(a, label_sector)) {
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a->msg = "disk label read failed";
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return SCAN_ERROR;
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}
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/* Locate disk label within block and validate */
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/*
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* XXX (dsl) This search may be a waste of time, a lot of other i386
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* code assumes the label is at offset LABELOFFSET (=0) in the sector.
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*
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* If we want to support diska from other netbsd ports, then the
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* code should also allow for a shorter label nearer the end of
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* the disk sector, and (IIRC) labels within 8k of the disk start.
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*/
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dlp_lim = (void *)(a->bp->b_data + a->lp->d_secsize - sizeof(*dlp));
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for (dlp = (void *)a->bp->b_data; dlp <= dlp_lim;
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dlp = (void *)((char *)dlp + sizeof(long))) {
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if (dlp->d_magic != DISKMAGIC || dlp->d_magic2 != DISKMAGIC)
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continue;
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if (dlp->d_npartitions > MAXPARTITIONS || dkcksum(dlp) != 0) {
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a->msg = "disk label corrupted";
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continue;
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}
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switch (action) {
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case READ_LABEL:
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*a->lp = *dlp;
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break;
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case WRITE_LABEL:
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*dlp = *a->lp;
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a->bp->b_flags &= ~(B_READ|B_DONE);
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a->bp->b_flags |= B_WRITE;
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(*a->strat)(a->bp);
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error = biowait(a->bp);
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if (error != 0) {
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a->error = error;
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a->msg = "disk label write failed";
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return SCAN_ERROR;
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}
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break;
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}
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return SCAN_FOUND;
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}
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return SCAN_CONTINUE;
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}
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/*
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* Check new disk label for sensibility
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* before setting it.
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*/
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int
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setdisklabel(olp, nlp, openmask, osdep)
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struct disklabel *olp, *nlp;
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u_long openmask;
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struct cpu_disklabel *osdep;
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{
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int i;
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struct partition *opp, *npp;
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/* sanity clause */
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if (nlp->d_secpercyl == 0 || nlp->d_secsize == 0
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|| (nlp->d_secsize % DEV_BSIZE) != 0)
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return (EINVAL);
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/* special case to allow disklabel to be invalidated */
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if (nlp->d_magic == 0xffffffff) {
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*olp = *nlp;
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return (0);
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}
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if (nlp->d_magic != DISKMAGIC || nlp->d_magic2 != DISKMAGIC ||
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dkcksum(nlp) != 0)
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return (EINVAL);
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/* XXX missing check if other dos partitions will be overwritten */
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while (openmask != 0) {
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i = ffs(openmask) - 1;
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openmask &= ~(1 << i);
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if (i > nlp->d_npartitions)
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return (EBUSY);
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opp = &olp->d_partitions[i];
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npp = &nlp->d_partitions[i];
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/*
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* Copy internally-set partition information
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* if new label doesn't include it. XXX
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*/
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if (npp->p_fstype == FS_UNUSED && opp->p_fstype != FS_UNUSED) {
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*npp = *opp;
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continue;
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}
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if (npp->p_offset != opp->p_offset || npp->p_size < opp->p_size)
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return (EBUSY);
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}
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nlp->d_checksum = 0;
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nlp->d_checksum = dkcksum(nlp);
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*olp = *nlp;
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return (0);
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}
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/*
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* Write disk label back to device after modification.
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*/
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int
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writedisklabel(dev, strat, lp, osdep)
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dev_t dev;
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void (*strat)(struct buf *);
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struct disklabel *lp;
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struct cpu_disklabel *osdep;
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{
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mbr_args_t a;
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int rval;
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a.lp = lp;
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a.strat = strat;
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a.msg = NULL;
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a.error = 0;
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/* get a buffer and initialize it */
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a.bp = geteblk((int)lp->d_secsize);
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a.bp->b_dev = dev;
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if (osdep)
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rval = scan_mbr(&a, write_netbsd_label);
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else
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rval = validate_label(&a, LABELSECTOR, WRITE_LABEL);
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if (rval != SCAN_FOUND && a.error == 0)
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a.error = ESRCH;
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brelse(a.bp);
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return a.error;
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}
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static int
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write_netbsd_label(mbr_args_t *a, mbr_partition_t *dp, int slot, uint ext_base)
|
|
{
|
|
int ptn_base = ext_base + le32toh(dp->mbrp_start);
|
|
int rval;
|
|
|
|
if (dp->mbrp_typ != MBR_PTYPE_NETBSD)
|
|
return SCAN_CONTINUE;
|
|
|
|
rval = validate_label(a, ptn_base + MBR_LABELSECTOR, WRITE_LABEL);
|
|
#ifdef notyet /* because the error reporting is wrong */
|
|
/* write label to all netbsd partitions */
|
|
if (rval == SCAN_FOUND)
|
|
return SCAN_CONTINUE;
|
|
#endif
|
|
return rval;
|
|
}
|
|
|
|
|
|
/*
|
|
* Determine the size of the transfer, and make sure it is
|
|
* within the boundaries of the partition. Adjust transfer
|
|
* if needed, and signal errors or early completion.
|
|
*/
|
|
int
|
|
bounds_check_with_label(dk, bp, wlabel)
|
|
struct disk *dk;
|
|
struct buf *bp;
|
|
int wlabel;
|
|
{
|
|
struct disklabel *lp = dk->dk_label;
|
|
struct partition *p = lp->d_partitions + DISKPART(bp->b_dev);
|
|
int labelsector = lp->d_partitions[2].p_offset + LABELSECTOR;
|
|
int sz;
|
|
|
|
sz = howmany(bp->b_bcount, lp->d_secsize);
|
|
|
|
if (bp->b_blkno + sz > p->p_size) {
|
|
sz = p->p_size - bp->b_blkno;
|
|
if (sz == 0) {
|
|
/* If exactly at end of disk, return EOF. */
|
|
bp->b_resid = bp->b_bcount;
|
|
return (0);
|
|
}
|
|
if (sz < 0) {
|
|
/* If past end of disk, return EINVAL. */
|
|
bp->b_error = EINVAL;
|
|
goto bad;
|
|
}
|
|
/* Otherwise, truncate request. */
|
|
bp->b_bcount = sz << DEV_BSHIFT;
|
|
}
|
|
|
|
/* Overwriting disk label? */
|
|
if (bp->b_blkno + p->p_offset <= labelsector &&
|
|
bp->b_blkno + p->p_offset + sz > labelsector &&
|
|
(bp->b_flags & B_READ) == 0 && !wlabel) {
|
|
bp->b_error = EROFS;
|
|
goto bad;
|
|
}
|
|
|
|
/* calculate cylinder for disksort to order transfers with */
|
|
bp->b_cylinder = (bp->b_blkno + p->p_offset) /
|
|
(lp->d_secsize / DEV_BSIZE) / lp->d_secpercyl;
|
|
return (1);
|
|
|
|
bad:
|
|
bp->b_flags |= B_ERROR;
|
|
return (-1);
|
|
}
|