1 /* $NetBSD: disksubr.c,v 1.29 2019/04/03 22:10:51 christos 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: disksubr.c,v 1.29 2019/04/03 22:10:51 christos Exp $");
36
37 #include <sys/param.h>
38 #include <sys/systm.h>
39 #include <sys/buf.h>
40 #include <sys/device.h>
41 #include <sys/disk.h>
42 #include <sys/disklabel.h>
43 #include <sys/kauth.h>
44 #include <sys/proc.h>
45
46 /*
47 * Attempt to read a disk label from a device
48 * using the indicated strategy routine.
49 * The label must be partly set up before this:
50 * secpercyl and anything required in the strategy routine
51 * (e.g., sector size) must be filled in before calling us.
52 * Returns null on success and an error string on failure.
53 */
54 const char *
readdisklabel(dev_t dev,void (* strat)(struct buf *),struct disklabel * lp,struct cpu_disklabel * osdep)55 readdisklabel(dev_t dev, void (*strat)(struct buf *), struct disklabel *lp,
56 struct cpu_disklabel *osdep)
57 {
58 struct buf *bp;
59 struct disklabel *dlp;
60 const char *msg = NULL;
61 int i;
62
63 if (lp->d_secsize == 0)
64 lp->d_secsize = DEV_BSIZE;
65 if (lp->d_secperunit == 0)
66 lp->d_secperunit = 0x1fffffff;
67 if (lp->d_npartitions < RAW_PART + 1)
68 lp->d_npartitions = RAW_PART + 1;
69 for (i = 0; i < RAW_PART; i++) {
70 lp->d_partitions[i].p_size = 0;
71 lp->d_partitions[i].p_offset = 0;
72 }
73 if (lp->d_partitions[RAW_PART].p_size == 0)
74 lp->d_partitions[RAW_PART].p_size = lp->d_secperunit;
75 lp->d_partitions[RAW_PART].p_offset = 0;
76
77 lp->d_partitions[0].p_size = lp->d_partitions[RAW_PART].p_size;
78 lp->d_partitions[0].p_fstype = FS_BSDFFS;
79
80 bp = geteblk((int)lp->d_secsize);
81 bp->b_dev = dev;
82 bp->b_blkno = LABELSECTOR;
83 bp->b_bcount = lp->d_secsize;
84 bp->b_flags |= B_READ;
85 bp->b_cylinder = LABELSECTOR / lp->d_secpercyl;
86 (*strat)(bp);
87 if (biowait(bp))
88 msg = "I/O error";
89 else for (dlp = (struct disklabel *)bp->b_data;
90 dlp <= (struct disklabel *)((char *)bp->b_data + DEV_BSIZE -
91 sizeof(*dlp));
92 dlp = (struct disklabel *)((char *)dlp + sizeof(long))) {
93 if (dlp->d_magic != DISKMAGIC || dlp->d_magic2 != DISKMAGIC) {
94 if (msg == NULL)
95 msg = "no disk label";
96 } else if (dlp->d_npartitions > MAXPARTITIONS ||
97 dkcksum(dlp) != 0)
98 msg = "disk label corrupted";
99 else {
100 *lp = *dlp;
101 msg = NULL;
102 break;
103 }
104 }
105 brelse(bp, 0);
106 return msg;
107 }
108
109 /*
110 * Write disk label back to device after modification.
111 */
112 int
writedisklabel(dev_t dev,void (* strat)(struct buf *),struct disklabel * lp,struct cpu_disklabel * osdep)113 writedisklabel(dev_t dev, void (*strat)(struct buf *), struct disklabel *lp,
114 struct cpu_disklabel *osdep)
115 {
116 struct buf *bp;
117 struct disklabel *dlp;
118 int labelpart;
119 int error = 0;
120
121 labelpart = DISKPART(dev);
122 if (lp->d_partitions[labelpart].p_offset != 0) {
123 if (lp->d_partitions[0].p_offset != 0)
124 return EXDEV; /* not quite right */
125 labelpart = 0;
126 }
127 bp = geteblk((int)lp->d_secsize);
128 bp->b_dev = MAKEDISKDEV(major(dev), DISKUNIT(dev), labelpart);
129 bp->b_blkno = LABELSECTOR;
130 bp->b_bcount = lp->d_secsize;
131 bp->b_flags |= B_READ;
132 (*strat)(bp);
133 if ((error = biowait(bp)) != 0)
134 goto done;
135 for (dlp = (struct disklabel *)bp->b_data;
136 dlp <= (struct disklabel *)
137 ((char *)bp->b_data + lp->d_secsize - sizeof(*dlp));
138 dlp = (struct disklabel *)((char *)dlp + sizeof(long))) {
139 if (dlp->d_magic == DISKMAGIC && dlp->d_magic2 == DISKMAGIC &&
140 dkcksum(dlp) == 0) {
141 *dlp = *lp;
142 bp->b_flags &= ~(B_READ);
143 bp->b_oflags &= ~(BO_DONE);
144 bp->b_flags |= B_WRITE;
145 (*strat)(bp);
146 error = biowait(bp);
147 goto done;
148 }
149 }
150 error = ESRCH;
151 done:
152 brelse(bp, 0);
153 return error;
154 }
155