1 /* $NetBSD: disksubr.c,v 1.28 2019/04/03 22:10:50 christos Exp $ */
2
3 /*
4 * Copyright (c) 1982, 1986, 1988, 1993
5 * The Regents of the University of California. All rights reserved.
6 * (c) UNIX System Laboratories, Inc.
7 * All or some portions of this file are derived from material licensed
8 * to the University of California by American Telephone and Telegraph
9 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
10 * the permission of UNIX System Laboratories, Inc.
11 *
12 * Redistribution and use in source and binary forms, with or without
13 * modification, are permitted provided that the following conditions
14 * are met:
15 * 1. Redistributions of source code must retain the above copyright
16 * notice, this list of conditions and the following disclaimer.
17 * 2. Redistributions in binary form must reproduce the above copyright
18 * notice, this list of conditions and the following disclaimer in the
19 * documentation and/or other materials provided with the distribution.
20 * 3. Neither the name of the University nor the names of its contributors
21 * may be used to endorse or promote products derived from this software
22 * without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 *
36 * @(#)ufs_disksubr.c 8.5 (Berkeley) 1/21/94
37 */
38
39 #include <sys/cdefs.h>
40 __KERNEL_RCSID(0, "$NetBSD: disksubr.c,v 1.28 2019/04/03 22:10:50 christos Exp $");
41
42 #include <sys/param.h>
43 #include <sys/systm.h>
44 #include <sys/buf.h>
45 #include <sys/disk.h>
46 #include <sys/disklabel.h>
47
48 /*
49 * Attempt to read a disk label from a device using the indicated strategy
50 * routine. The label must be partly set up before this: secpercyl and
51 * anything required in the strategy routine (e.g., sector size) must be
52 * filled in before calling us. Returns null on success and an error
53 * string on failure.
54 */
55 const char *
readdisklabel(dev_t dev,void (* strat)(struct buf *),struct disklabel * lp,struct cpu_disklabel * osdep)56 readdisklabel(dev_t dev, void (*strat)(struct buf *), struct disklabel *lp,
57 struct cpu_disklabel *osdep)
58 {
59 struct buf *bp;
60 struct disklabel *dlp;
61 const char *msg = NULL;
62 int i;
63
64 if (lp->d_secsize == 0)
65 lp->d_secsize = DEV_BSIZE;
66 if (lp->d_secperunit == 0)
67 lp->d_secperunit = 0x1fffffff;
68 if (lp->d_npartitions < RAW_PART + 1)
69 lp->d_npartitions = RAW_PART + 1;
70 for (i = 0; i < RAW_PART; i++) {
71 lp->d_partitions[i].p_size = 0;
72 lp->d_partitions[i].p_offset = 0;
73 }
74 if (lp->d_partitions[RAW_PART].p_size == 0)
75 lp->d_partitions[RAW_PART].p_size = lp->d_secperunit;
76 lp->d_partitions[RAW_PART].p_offset = 0;
77
78 lp->d_partitions[0].p_size = lp->d_partitions[RAW_PART].p_size;
79 lp->d_partitions[0].p_fstype = FS_BSDFFS;
80
81 bp = geteblk((int)lp->d_secsize);
82 bp->b_dev = dev;
83 bp->b_blkno = LABELSECTOR;
84 bp->b_bcount = lp->d_secsize;
85 bp->b_flags |= B_READ;
86 bp->b_cylinder = LABELSECTOR / lp->d_secpercyl;
87 (*strat)(bp);
88 if (biowait(bp))
89 msg = "I/O error";
90 else for (dlp = (struct disklabel *)bp->b_data;
91 dlp <= (struct disklabel *)((char *)bp->b_data +
92 DEV_BSIZE - sizeof(*dlp));
93 dlp = (struct disklabel *)((char *)dlp + sizeof(long))) {
94 if (dlp->d_magic != DISKMAGIC || dlp->d_magic2 != DISKMAGIC) {
95 if (msg == NULL)
96 msg = "no disk label";
97 } else if (dlp->d_npartitions > MAXPARTITIONS ||
98 dkcksum(dlp) != 0)
99 msg = "disk label corrupted";
100 else {
101 *lp = *dlp;
102 msg = NULL;
103 break;
104 }
105 }
106 brelse(bp, 0);
107 return msg;
108 }
109
110 /*
111 * Write disk label back to device after modification.
112 */
113 int
writedisklabel(dev_t dev,void (* strat)(struct buf *),struct disklabel * lp,struct cpu_disklabel * osdep)114 writedisklabel(dev_t dev, void (*strat)(struct buf *), struct disklabel *lp,
115 struct cpu_disklabel *osdep)
116 {
117 struct buf *bp;
118 struct disklabel *dlp;
119 int labelpart;
120 int error = 0;
121
122 labelpart = DISKPART(dev);
123 if (lp->d_partitions[labelpart].p_offset != 0) {
124 if (lp->d_partitions[0].p_offset != 0)
125 return EXDEV; /* not quite right */
126 labelpart = 0;
127 }
128 bp = geteblk((int)lp->d_secsize);
129 bp->b_dev = MAKEDISKDEV(major(dev), DISKUNIT(dev), labelpart);
130 bp->b_blkno = LABELSECTOR;
131 bp->b_bcount = lp->d_secsize;
132 bp->b_flags |= B_READ;
133 (*strat)(bp);
134 if ((error = biowait(bp)) != 0)
135 goto done;
136 for (dlp = (struct disklabel *)bp->b_data;
137 dlp <= (struct disklabel *)
138 ((char *)bp->b_data + lp->d_secsize - sizeof(*dlp));
139 dlp = (struct disklabel *)((char *)dlp + sizeof(long))) {
140 if (dlp->d_magic == DISKMAGIC && dlp->d_magic2 == DISKMAGIC &&
141 dkcksum(dlp) == 0) {
142 *dlp = *lp;
143 bp->b_oflags &= ~(BO_DONE);
144 bp->b_flags &= ~(B_READ);
145 bp->b_flags |= B_WRITE;
146 (*strat)(bp);
147 error = biowait(bp);
148 goto done;
149 }
150 }
151 error = ESRCH;
152 done:
153 brelse(bp, 0);
154 return error;
155 }
156