xref: /openbsd-src/sys/arch/i386/i386/disksubr.c (revision b986024f4810ac33f68c6b682e41c7faeb9a3d97)
1 /*	$OpenBSD: disksubr.c,v 1.116 2017/02/28 10:49:37 natano Exp $	*/
2 /*	$NetBSD: disksubr.c,v 1.21 1996/05/03 19:42:03 christos Exp $	*/
3 
4 /*
5  * Copyright (c) 1996 Theo de Raadt
6  * Copyright (c) 1982, 1986, 1988 Regents of the University of California.
7  * All rights reserved.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in the
16  *    documentation and/or other materials provided with the distribution.
17  * 3. Neither the name of the University nor the names of its contributors
18  *    may be used to endorse or promote products derived from this software
19  *    without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  */
33 
34 #include <sys/param.h>
35 #include <sys/buf.h>
36 #include <sys/disklabel.h>
37 #include <sys/disk.h>
38 #include <sys/reboot.h>
39 #include <sys/conf.h>
40 
41 #ifdef DEBUG
42 #include <sys/systm.h>
43 #endif
44 
45 #include <machine/biosvar.h>
46 
47 bios_diskinfo_t *bios_getdiskinfo(dev_t dev);
48 
49 /*
50  * Attempt to read a disk label from a device
51  * using the indicated strategy routine.
52  * The label must be partly set up before this:
53  * secpercyl, secsize and anything required for a block i/o read
54  * operation in the driver's strategy/start routines
55  * must be filled in before calling us.
56  *
57  * If dos partition table requested, attempt to load it and
58  * find disklabel inside a DOS partition.
59  *
60  * We would like to check if each MBR has a valid DOSMBR_SIGNATURE, but
61  * we cannot because it doesn't always exist. So.. we assume the
62  * MBR is valid.
63  */
64 int
readdisklabel(dev_t dev,void (* strat)(struct buf *),struct disklabel * lp,int spoofonly)65 readdisklabel(dev_t dev, void (*strat)(struct buf *),
66     struct disklabel *lp, int spoofonly)
67 {
68 	bios_diskinfo_t *pdi;
69 	struct buf *bp = NULL;
70 	dev_t devno;
71 	int error;
72 
73 	if ((error = initdisklabel(lp)))
74 		goto done;
75 
76 	/* Look for any BIOS geometry information we should honour. */
77 	devno = chrtoblk(dev);
78 	if (devno == NODEV)
79 		devno = dev;
80 	pdi = bios_getdiskinfo(MAKEBOOTDEV(major(devno), 0, 0, DISKUNIT(devno),
81 	    RAW_PART));
82 	if (pdi != NULL && pdi->bios_heads > 0 && pdi->bios_sectors > 0) {
83 #ifdef DEBUG
84 		printf("Disk GEOM %u/%u/%u -> BIOS GEOM %u/%u/%llu\n",
85 		    lp->d_ntracks, lp->d_nsectors, lp->d_ncylinders,
86 		    pdi->bios_heads, pdi->bios_sectors,
87 		    DL_GETDSIZE(lp) / (pdi->bios_heads * pdi->bios_sectors));
88 #endif
89 		lp->d_ntracks = pdi->bios_heads;
90 		lp->d_nsectors = pdi->bios_sectors;
91 		lp->d_secpercyl = pdi->bios_sectors * pdi->bios_heads;
92 		lp->d_ncylinders = DL_GETDSIZE(lp) / lp->d_secpercyl;
93 	}
94 
95 	/* get a buffer and initialize it */
96 	bp = geteblk(lp->d_secsize);
97 	bp->b_dev = dev;
98 
99 	error = readdoslabel(bp, strat, lp, NULL, spoofonly);
100 	if (error == 0)
101 		goto done;
102 
103 #if defined(CD9660)
104 	error = iso_disklabelspoof(dev, strat, lp);
105 	if (error == 0)
106 		goto done;
107 #endif
108 #if defined(UDF)
109 	error = udf_disklabelspoof(dev, strat, lp);
110 	if (error == 0)
111 		goto done;
112 #endif
113 
114 done:
115 	if (bp) {
116 		bp->b_flags |= B_INVAL;
117 		brelse(bp);
118 	}
119 	disk_change = 1;
120 	return (error);
121 }
122 
123 /*
124  * Write disk label back to device after modification.
125  */
126 int
writedisklabel(dev_t dev,void (* strat)(struct buf *),struct disklabel * lp)127 writedisklabel(dev_t dev, void (*strat)(struct buf *), struct disklabel *lp)
128 {
129 	daddr_t partoff = -1;
130 	int error = EIO;
131 	int offset;
132 	struct disklabel *dlp;
133 	struct buf *bp = NULL;
134 
135 	/* get a buffer and initialize it */
136 	bp = geteblk(lp->d_secsize);
137 	bp->b_dev = dev;
138 
139 	if (readdoslabel(bp, strat, lp, &partoff, 1) != 0)
140 		goto done;
141 
142 	/* Read it in, slap the new label in, and write it back out */
143 	error = readdisksector(bp, strat, lp, DL_BLKTOSEC(lp, partoff +
144 	    DOS_LABELSECTOR));
145 	if (error)
146 		goto done;
147 	offset = DL_BLKOFFSET(lp, partoff + DOS_LABELSECTOR);
148 
149 	dlp = (struct disklabel *)(bp->b_data + offset);
150 	*dlp = *lp;
151 	CLR(bp->b_flags, B_READ | B_WRITE | B_DONE);
152 	SET(bp->b_flags, B_BUSY | B_WRITE | B_RAW);
153 	(*strat)(bp);
154 	error = biowait(bp);
155 
156 done:
157 	if (bp) {
158 		bp->b_flags |= B_INVAL;
159 		brelse(bp);
160 	}
161 	disk_change = 1;
162 	return (error);
163 }
164