1 /* $NetBSD: disksubr.c,v 1.20 2026/07/14 13:34:34 thorpej 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 1.20 2026/07/14 13:34:34 thorpej Exp $"); 36 37 #include <sys/param.h> 38 #include <sys/systm.h> 39 #include <sys/buf.h> 40 #include <sys/disklabel.h> 41 #include <sys/disk.h> 42 #include <sys/syslog.h> 43 44 /* 45 * Attempt to read a disk label from a device 46 * using the indicated strategy routine. 47 * The label must be partly set up before this: 48 * secpercyl, secsize and anything required for a block i/o read 49 * operation in the driver's strategy/start routines 50 * must be filled in before calling us. 51 * 52 * If dos partition table requested, attempt to load it and 53 * find disklabel inside a DOS partition. Also, if bad block 54 * table needed, attempt to extract it as well. Return buffer 55 * for use in signalling errors if requested. 56 * 57 * Returns null on success and an error string on failure. 58 */ 59 const char * 60 readdisklabel(dev_t dev, void (*strat)(struct buf *), struct disklabel *lp, 61 struct cpu_disklabel *osdep) 62 { 63 struct buf *bp; 64 struct disklabel *dlp; 65 const char *msg = NULL; 66 67 /* minimal requirements for archetypal disk label */ 68 if (lp->d_secsize == 0) 69 lp->d_secsize = DEV_BSIZE; 70 if (lp->d_secperunit == 0) 71 lp->d_secperunit = 0x1fffffff; 72 lp->d_npartitions = RAW_PART + 1; 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 /* get a buffer and initialize it */ 78 bp = geteblk((int)lp->d_secsize); 79 80 /* next, dig out disk label */ 81 bp->b_dev = dev; 82 bp->b_blkno = LABELSECTOR; 83 bp->b_cylinder = 0; 84 bp->b_bcount = lp->d_secsize; 85 bp->b_flags |= B_READ; 86 (*strat)(bp); 87 88 /* if successful, locate disk label within block and validate */ 89 if (biowait(bp)) { 90 msg = "disk label I/O error"; 91 goto done; 92 } 93 94 for (dlp = (struct disklabel *)bp->b_data; 95 dlp <= (struct disklabel *)((char *)bp->b_data + lp->d_secsize - 96 sizeof(*dlp)); 97 dlp = (struct disklabel *)((char *)dlp + sizeof(long))) { 98 if (dlp->d_magic != DISKMAGIC || dlp->d_magic2 != DISKMAGIC) { 99 if (msg == NULL) 100 msg = "no disk label"; 101 } else if (dlp->d_npartitions > MAXPARTITIONS || 102 dkcksum(dlp) != 0) 103 msg = "disk label corrupted"; 104 else { 105 *lp = *dlp; 106 msg = NULL; 107 break; 108 } 109 } 110 111 done: 112 brelse(bp, BC_INVAL); 113 return (msg); 114 } 115 116 117 /* 118 * Write disk label back to device after modification. 119 */ 120 int 121 writedisklabel(dev_t dev, void (*strat)(struct buf *), struct disklabel *lp, 122 struct cpu_disklabel *osdep) 123 { 124 struct buf *bp; 125 struct disklabel *dlp; 126 int error; 127 128 #ifdef maybe 129 /* disklabel in appropriate location? */ 130 if (lp->d_partitions[2].p_offset != 0 131 && lp->d_partitions[2].p_offset != dospartoff) { 132 error = EXDEV; 133 goto done; 134 } 135 #endif 136 137 /* get a buffer and initialize it */ 138 bp = geteblk((int)lp->d_secsize); 139 bp->b_dev = dev; 140 bp->b_blkno = LABELSECTOR; 141 bp->b_cylinder = 0; 142 bp->b_bcount = lp->d_secsize; 143 bp->b_flags |= B_READ; 144 (*strat)(bp); 145 146 /* if successful, locate disk label within block and validate */ 147 if ((error = biowait(bp)) != 0) 148 goto done; 149 for (dlp = (struct disklabel *)bp->b_data; 150 dlp <= (struct disklabel *)((char *)bp->b_data + lp->d_secsize - 151 sizeof(*dlp)); 152 dlp = (struct disklabel *)((char *)dlp + sizeof(long))) { 153 if (dlp->d_magic == DISKMAGIC && dlp->d_magic2 == DISKMAGIC && 154 dkcksum(dlp) == 0) { 155 *dlp = *lp; 156 bp->b_cflags = BC_BUSY; 157 bp->b_flags = B_WRITE; 158 CLR(bp->b_oflags, BO_DONE); 159 (*strat)(bp); 160 error = biowait(bp); 161 goto done; 162 } 163 } 164 error = ESRCH; 165 166 done: 167 brelse(bp, 0); 168 return (error); 169 } 170
Indexes created Sun Oct 25 00:26:45 UTC 2026