1 /* $NetBSD: disksubr.c,v 1.9 2002/03/05 09:40:40 simonb 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. All advertising materials mentioning features or use of this software 16 * must display the following acknowledgement: 17 * This product includes software developed by the University of 18 * California, Berkeley and its contributors. 19 * 4. Neither the name of the University nor the names of its contributors 20 * may be used to endorse or promote products derived from this software 21 * without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 * 35 * @(#)ufs_disksubr.c 7.16 (Berkeley) 5/4/91 36 */ 37 38 #include <sys/param.h> 39 #include <sys/systm.h> 40 #include <sys/buf.h> 41 #include <sys/device.h> 42 #include <sys/disk.h> 43 #include <sys/disklabel.h> 44 45 /* 46 * Attempt to read a disk label from a device 47 * using the indicated strategy routine. 48 * The label must be partly set up before this: 49 * secpercyl and anything required in the strategy routine 50 * (e.g., sector size) must be filled in before calling us. 51 * Returns null on success and an error string on failure. 52 */ 53 char * 54 readdisklabel(dev, strat, lp, osdep) 55 dev_t dev; 56 void (*strat) __P((struct buf *bp)); 57 struct disklabel *lp; 58 struct cpu_disklabel *osdep; 59 { 60 struct buf *bp; 61 struct disklabel *dlp; 62 char *msg = NULL; 63 64 if (lp->d_secperunit == 0) 65 lp->d_secperunit = 0x1fffffff; 66 lp->d_npartitions = 1; 67 if (lp->d_partitions[0].p_size == 0) 68 lp->d_partitions[0].p_size = 0x1fffffff; 69 lp->d_partitions[0].p_offset = 0; 70 71 bp = geteblk((int)lp->d_secsize); 72 bp->b_dev = dev; 73 bp->b_blkno = LABELSECTOR; 74 bp->b_bcount = lp->d_secsize; 75 bp->b_flags |= B_READ; 76 bp->b_cylinder = LABELSECTOR / lp->d_secpercyl; 77 (*strat)(bp); 78 if (biowait(bp)) { 79 msg = "I/O error"; 80 } else for (dlp = (struct disklabel *)bp->b_data; 81 dlp <= (struct disklabel *)(bp->b_data+DEV_BSIZE-sizeof(*dlp)); 82 dlp = (struct disklabel *)((char *)dlp + sizeof(long))) { 83 if (dlp->d_magic != DISKMAGIC || dlp->d_magic2 != DISKMAGIC) { 84 if (msg == NULL) 85 msg = "no disk label"; 86 } else if (dlp->d_npartitions > MAXPARTITIONS || 87 dkcksum(dlp) != 0) 88 msg = "disk label corrupted"; 89 else { 90 *lp = *dlp; 91 msg = NULL; 92 break; 93 } 94 } 95 brelse(bp); 96 return (msg); 97 } 98 99 /* 100 * Check new disk label for sensibility 101 * before setting it. 102 */ 103 int 104 setdisklabel(olp, nlp, openmask, osdep) 105 struct disklabel *olp, *nlp; 106 u_long openmask; 107 struct cpu_disklabel *osdep; 108 { 109 int i; 110 struct partition *opp, *npp; 111 112 if (nlp->d_magic != DISKMAGIC || nlp->d_magic2 != DISKMAGIC || 113 dkcksum(nlp) != 0) 114 return (EINVAL); 115 while ((i = ffs(openmask)) != 0) { 116 i--; 117 openmask &= ~(1 << i); 118 if (nlp->d_npartitions <= i) 119 return (EBUSY); 120 opp = &olp->d_partitions[i]; 121 npp = &nlp->d_partitions[i]; 122 if (npp->p_offset != opp->p_offset || npp->p_size < opp->p_size) 123 return (EBUSY); 124 /* 125 * Copy internally-set partition information 126 * if new label doesn't include it. XXX 127 */ 128 if (npp->p_fstype == FS_UNUSED && opp->p_fstype != FS_UNUSED) { 129 npp->p_fstype = opp->p_fstype; 130 npp->p_fsize = opp->p_fsize; 131 npp->p_frag = opp->p_frag; 132 npp->p_cpg = opp->p_cpg; 133 } 134 } 135 nlp->d_checksum = 0; 136 nlp->d_checksum = dkcksum(nlp); 137 *olp = *nlp; 138 return (0); 139 } 140 141 /* 142 * Write disk label back to device after modification. 143 */ 144 int 145 writedisklabel(dev, strat, lp, osdep) 146 dev_t dev; 147 void (*strat) __P((struct buf *bp)); 148 struct disklabel *lp; 149 struct cpu_disklabel *osdep; 150 { 151 struct buf *bp; 152 struct disklabel *dlp; 153 int labelpart; 154 int error = 0; 155 156 labelpart = DISKPART(dev); 157 if (lp->d_partitions[labelpart].p_offset != 0) { 158 if (lp->d_partitions[0].p_offset != 0) 159 return (EXDEV); /* not quite right */ 160 labelpart = 0; 161 } 162 bp = geteblk((int)lp->d_secsize); 163 bp->b_dev = makedev(major(dev), DISKMINOR(DISKUNIT(dev), labelpart)); 164 bp->b_blkno = LABELSECTOR; 165 bp->b_bcount = lp->d_secsize; 166 bp->b_flags |= B_READ; 167 (*strat)(bp); 168 if ((error = biowait(bp)) != 0) 169 goto done; 170 for (dlp = (struct disklabel *)bp->b_data; 171 dlp <= (struct disklabel *) 172 (bp->b_data + lp->d_secsize - sizeof(*dlp)); 173 dlp = (struct disklabel *)((char *)dlp + sizeof(long))) { 174 if (dlp->d_magic == DISKMAGIC && dlp->d_magic2 == DISKMAGIC && 175 dkcksum(dlp) == 0) { 176 *dlp = *lp; 177 bp->b_flags &= ~(B_READ|B_DONE); 178 bp->b_flags |= B_WRITE; 179 (*strat)(bp); 180 error = biowait(bp); 181 goto done; 182 } 183 } 184 error = ESRCH; 185 done: 186 brelse(bp); 187 return (error); 188 } 189 190 /* 191 * UNTESTED !! 192 * 193 * Determine the size of the transfer, and make sure it is 194 * within the boundaries of the partition. Adjust transfer 195 * if needed, and signal errors or early completion. 196 */ 197 int 198 bounds_check_with_label(bp, lp, wlabel) 199 struct buf *bp; 200 struct disklabel *lp; 201 int wlabel; 202 { 203 204 struct partition *p = lp->d_partitions + DISKPART(bp->b_dev); 205 int labelsect = lp->d_partitions[0].p_offset; 206 int maxsz = p->p_size; 207 int sz = (bp->b_bcount + DEV_BSIZE - 1) >> DEV_BSHIFT; 208 209 /* overwriting disk label ? */ 210 /* XXX should also protect bootstrap in first 8K */ 211 if (bp->b_blkno + p->p_offset <= LABELSECTOR + labelsect && 212 (bp->b_flags & B_READ) == 0 && wlabel == 0) { 213 bp->b_error = EROFS; 214 goto bad; 215 } 216 217 /* beyond partition? */ 218 if (bp->b_blkno < 0 || bp->b_blkno + sz > maxsz) { 219 /* if exactly at end of disk, return an EOF */ 220 if (bp->b_blkno == maxsz) { 221 bp->b_resid = bp->b_bcount; 222 return(0); 223 } 224 /* or truncate if part of it fits */ 225 sz = maxsz - bp->b_blkno; 226 if (sz <= 0) { 227 bp->b_error = EINVAL; 228 goto bad; 229 } 230 bp->b_bcount = sz << DEV_BSHIFT; 231 } 232 233 /* calculate cylinder for disksort to order transfers with */ 234 bp->b_resid = (bp->b_blkno + p->p_offset) / lp->d_secpercyl; 235 return(1); 236 bad: 237 bp->b_flags |= B_ERROR; 238 return(-1); 239 } 240