1 /* $NetBSD: disksubr.c,v 1.8 2002/05/20 20:49:16 jdolecek 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. All advertising materials mentioning features or use of this software 21 * must display the following acknowledgement: 22 * This product includes software developed by the University of 23 * California, Berkeley and its contributors. 24 * 4. Neither the name of the University nor the names of its contributors 25 * may be used to endorse or promote products derived from this software 26 * without specific prior written permission. 27 * 28 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 29 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 30 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 31 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 32 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 33 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 34 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 35 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 36 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 37 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 38 * SUCH DAMAGE. 39 * 40 * @(#)ufs_disksubr.c 8.5 (Berkeley) 1/21/94 41 */ 42 43 #include <sys/param.h> 44 #include <sys/systm.h> 45 #include <sys/buf.h> 46 #include <sys/disklabel.h> 47 #include <sys/syslog.h> 48 49 #include <sys/disk.h> 50 51 #define b_cylinder b_resid 52 53 /* 54 * Attempt to read a disk label from a device using the indicated strategy 55 * routine. The label must be partly set up before this: secpercyl and 56 * anything required in the strategy routine (e.g., sector size) must be 57 * filled in before calling us. Returns null on success and an error 58 * string on failure. 59 */ 60 char * 61 readdisklabel(dev, strat, lp, osdep) 62 dev_t dev; 63 void (*strat) __P((struct buf *)); 64 struct disklabel *lp; 65 struct cpu_disklabel *osdep; 66 { 67 struct buf *bp; 68 struct disklabel *dlp; 69 char *msg = NULL; 70 int i; 71 72 /* minimal requirements for archtypal disk label */ 73 if (lp->d_secsize == 0) 74 lp->d_secsize = DEV_BSIZE; 75 if (lp->d_secperunit == 0) 76 lp->d_secperunit = 0x1fffffff; 77 lp->d_npartitions = RAW_PART + 1; 78 for (i = 0; i < RAW_PART; i++) { 79 lp->d_partitions[i].p_size = 0; 80 lp->d_partitions[i].p_offset = 0; 81 } 82 if (lp->d_partitions[i].p_size == 0) 83 lp->d_partitions[i].p_size = 0x1fffffff; 84 lp->d_partitions[i].p_offset = 0; 85 86 bp = geteblk((int)lp->d_secsize); 87 bp->b_dev = dev; 88 bp->b_blkno = LABELSECTOR; 89 bp->b_bcount = lp->d_secsize; 90 bp->b_flags |= B_READ; 91 bp->b_cylinder = LABELSECTOR / lp->d_secpercyl; 92 (*strat)(bp); 93 if (biowait(bp)) 94 msg = "I/O error"; 95 else for (dlp = (struct disklabel *)bp->b_data; 96 dlp <= (struct disklabel *)((char *)bp->b_data + 97 DEV_BSIZE - sizeof(*dlp)); 98 dlp = (struct disklabel *)((char *)dlp + sizeof(long))) { 99 if (dlp->d_magic != DISKMAGIC || dlp->d_magic2 != DISKMAGIC) { 100 if (msg == NULL) 101 msg = "no disk label"; 102 } else if (dlp->d_npartitions > MAXPARTITIONS || 103 dkcksum(dlp) != 0) 104 msg = "disk label corrupted"; 105 else { 106 *lp = *dlp; 107 msg = NULL; 108 break; 109 } 110 } 111 brelse(bp); 112 return (msg); 113 } 114 115 /* 116 * Check new disk label for sensibility before setting it. 117 */ 118 int 119 setdisklabel(olp, nlp, openmask, osdep) 120 struct disklabel *olp, *nlp; 121 u_long openmask; 122 struct cpu_disklabel *osdep; 123 { 124 int i; 125 struct partition *opp, *npp; 126 127 if (nlp->d_magic != DISKMAGIC || nlp->d_magic2 != DISKMAGIC || 128 dkcksum(nlp) != 0) 129 return (EINVAL); 130 while ((i = ffs(openmask)) != 0) { 131 i--; 132 openmask &= ~(1 << i); 133 if (nlp->d_npartitions <= i) 134 return (EBUSY); 135 opp = &olp->d_partitions[i]; 136 npp = &nlp->d_partitions[i]; 137 if (npp->p_offset != opp->p_offset || npp->p_size < opp->p_size) 138 return (EBUSY); 139 /* 140 * Copy internally-set partition information 141 * if new label doesn't include it. XXX 142 */ 143 if (npp->p_fstype == FS_UNUSED && opp->p_fstype != FS_UNUSED) { 144 npp->p_fstype = opp->p_fstype; 145 npp->p_fsize = opp->p_fsize; 146 npp->p_frag = opp->p_frag; 147 npp->p_cpg = opp->p_cpg; 148 } 149 } 150 nlp->d_checksum = 0; 151 nlp->d_checksum = dkcksum(nlp); 152 *olp = *nlp; 153 return (0); 154 } 155 156 /* 157 * Write disk label back to device after modification. 158 */ 159 int 160 writedisklabel(dev, strat, lp, osdep) 161 dev_t dev; 162 void (*strat) __P((struct buf *)); 163 struct disklabel *lp; 164 struct cpu_disklabel *osdep; 165 { 166 struct buf *bp; 167 struct disklabel *dlp; 168 int labelpart; 169 int error = 0; 170 171 labelpart = DISKPART(dev); 172 if (lp->d_partitions[labelpart].p_offset != 0) { 173 if (lp->d_partitions[0].p_offset != 0) 174 return (EXDEV); /* not quite right */ 175 labelpart = 0; 176 } 177 bp = geteblk((int)lp->d_secsize); 178 bp->b_dev = MAKEDISKDEV(major(dev), DISKUNIT(dev), labelpart); 179 bp->b_blkno = LABELSECTOR; 180 bp->b_bcount = lp->d_secsize; 181 bp->b_flags |= B_READ; 182 (*strat)(bp); 183 if ((error = biowait(bp))) 184 goto done; 185 for (dlp = (struct disklabel *)bp->b_data; 186 dlp <= (struct disklabel *) 187 ((char *)bp->b_data + lp->d_secsize - sizeof(*dlp)); 188 dlp = (struct disklabel *)((char *)dlp + sizeof(long))) { 189 if (dlp->d_magic == DISKMAGIC && dlp->d_magic2 == DISKMAGIC && 190 dkcksum(dlp) == 0) { 191 *dlp = *lp; 192 bp->b_flags &= ~(B_READ|B_DONE); 193 bp->b_flags |= B_WRITE; 194 (*strat)(bp); 195 error = biowait(bp); 196 goto done; 197 } 198 } 199 error = ESRCH; 200 done: 201 brelse(bp); 202 return (error); 203 } 204 205 /* 206 * Determine the size of the transfer, and make sure it is 207 * within the boundaries of the partition. Adjust transfer 208 * if needed, and signal errors or early completion. 209 */ 210 int 211 bounds_check_with_label(bp, lp, wlabel) 212 struct buf *bp; 213 struct disklabel *lp; 214 int wlabel; 215 { 216 struct partition *p = &lp->d_partitions[DISKPART(bp->b_dev)]; 217 int labelsect = lp->d_partitions[0].p_offset; 218 int maxsz = p->p_size; 219 int sz = (bp->b_bcount + DEV_BSIZE - 1) >> DEV_BSHIFT; 220 221 /* Overwriting disk label? */ 222 if (bp->b_blkno + p->p_offset <= LABELSECTOR + labelsect && 223 (bp->b_flags & B_READ) == 0 && !wlabel) { 224 bp->b_error = EROFS; 225 goto bad; 226 } 227 228 /* beyond partition? */ 229 if (bp->b_blkno < 0 || bp->b_blkno + sz > maxsz) { 230 if (bp->b_blkno == maxsz) { 231 /* If exactly at end of disk, return EOF. */ 232 bp->b_resid = bp->b_bcount; 233 return (0); 234 } 235 /* ...or truncate if part of it fits */ 236 sz = maxsz - bp->b_blkno; 237 if (sz <= 0) { 238 bp->b_error = EINVAL; 239 goto bad; 240 } 241 bp->b_bcount = sz << DEV_BSHIFT; 242 } 243 244 /* calculate cylinder for disksort to order transfers with */ 245 bp->b_resid = (bp->b_blkno + p->p_offset) / lp->d_secpercyl; 246 return (1); 247 248 bad: 249 bp->b_flags |= B_ERROR; 250 return (-1); 251 } 252