1 /* $OpenBSD: msdosfs_vfsops.c,v 1.11 2016/12/17 16:43:30 krw Exp $ */ 2 3 /*- 4 * Copyright (C) 1994, 1995, 1997 Wolfgang Solfrank. 5 * Copyright (C) 1994, 1995, 1997 TooLs GmbH. 6 * All rights reserved. 7 * Original code by Paul Popelka (paulp@uts.amdahl.com) (see below). 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. All advertising materials mentioning features or use of this software 18 * must display the following acknowledgement: 19 * This product includes software developed by TooLs GmbH. 20 * 4. The name of TooLs GmbH may not be used to endorse or promote products 21 * derived from this software without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``AS IS'' AND ANY EXPRESS OR 24 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 25 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 26 * IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 27 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 28 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; 29 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 30 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR 31 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF 32 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 33 */ 34 /* 35 * Written by Paul Popelka (paulp@uts.amdahl.com) 36 * 37 * You can do anything you want with this software, just don't say you wrote 38 * it, and don't remove this notice. 39 * 40 * This software is provided "as is". 41 * 42 * The author supplies this software to be publicly redistributed on the 43 * understanding that the author is not responsible for the correct 44 * functioning of this software in any circumstances and is not liable for 45 * any damages caused by this software. 46 * 47 * October 1992 48 */ 49 50 #include <sys/param.h> 51 #include <sys/time.h> 52 53 #include "ffs/buf.h" 54 55 #include <msdosfs/bpb.h> 56 #include <msdosfs/bootsect.h> 57 #include "msdos/direntry.h" 58 #include "msdos/denode.h" 59 #include "msdos/msdosfsmount.h" 60 #include "msdos/fat.h" 61 62 #include <stdio.h> 63 #include <errno.h> 64 #include <stdlib.h> 65 #include <string.h> 66 #include <util.h> 67 68 #include "makefs.h" 69 #include "msdos.h" 70 #include "msdos/mkfs_msdos.h" 71 72 #ifdef MSDOSFS_DEBUG 73 #define DPRINTF(a) printf a 74 #else 75 #define DPRINTF(a) 76 #endif 77 78 struct msdosfsmount * 79 msdosfs_mount(struct mkfsvnode *devvp, int flags) 80 { 81 struct msdosfsmount *pmp = NULL; 82 struct mkfsbuf *bp; 83 union bootsector *bsp; 84 struct byte_bpb33 *b33; 85 struct byte_bpb50 *b50; 86 struct byte_bpb710 *b710; 87 uint8_t SecPerClust; 88 int ronly = 0, error; 89 int bsize; 90 struct timezone tz; 91 unsigned secsize = 512; 92 93 DPRINTF(("%s(bread 0)\n", __func__)); 94 if ((error = bread(devvp, 0, secsize, 0, &bp)) != 0) 95 goto error_exit; 96 97 bsp = (union bootsector *)bp->b_data; 98 b33 = (struct byte_bpb33 *)bsp->bs33.bsBPB; 99 b50 = (struct byte_bpb50 *)bsp->bs50.bsBPB; 100 b710 = (struct byte_bpb710 *)bsp->bs710.bsBPB; 101 102 if (bsp->bs50.bsBootSectSig0 != BOOTSIG0 103 || bsp->bs50.bsBootSectSig1 != BOOTSIG1) { 104 DPRINTF(("bootsig0 %d bootsig1 %d\n", 105 bsp->bs50.bsBootSectSig0, 106 bsp->bs50.bsBootSectSig1)); 107 error = EINVAL; 108 goto error_exit; 109 } 110 bsize = 0; 111 112 pmp = ecalloc(1, sizeof *pmp); 113 /* 114 * Compute several useful quantities from the bpb in the 115 * bootsector. Copy in the dos 5 variant of the bpb then fix up 116 * the fields that are different between dos 5 and dos 3.3. 117 */ 118 SecPerClust = b50->bpbSecPerClust; 119 pmp->pm_BytesPerSec = getushort(b50->bpbBytesPerSec); 120 pmp->pm_ResSectors = getushort(b50->bpbResSectors); 121 pmp->pm_FATs = b50->bpbFATs; 122 pmp->pm_RootDirEnts = getushort(b50->bpbRootDirEnts); 123 pmp->pm_Sectors = getushort(b50->bpbSectors); 124 pmp->pm_FATsecs = getushort(b50->bpbFATsecs); 125 pmp->pm_SecPerTrack = getushort(b50->bpbSecPerTrack); 126 pmp->pm_Heads = getushort(b50->bpbHeads); 127 pmp->pm_Media = b50->bpbMedia; 128 129 if (gettimeofday(NULL, &tz) == -1) { 130 error = errno; 131 goto error_exit; 132 } 133 pmp->pm_minuteswest = tz.tz_minuteswest; 134 135 DPRINTF(("%s(BytesPerSec=%u, ResSectors=%u, FATs=%d, RootDirEnts=%u, " 136 "Sectors=%u, FATsecs=%lu, SecPerTrack=%u, Heads=%u, Media=%u)\n", 137 __func__, pmp->pm_BytesPerSec, pmp->pm_ResSectors, pmp->pm_FATs, 138 pmp->pm_RootDirEnts, pmp->pm_Sectors, pmp->pm_FATsecs, 139 pmp->pm_SecPerTrack, pmp->pm_Heads, pmp->pm_Media)); 140 /* XXX - We should probably check more values here */ 141 if (!pmp->pm_BytesPerSec || !SecPerClust 142 || pmp->pm_SecPerTrack > 63) { 143 DPRINTF(("bytespersec %d secperclust %d " 144 "secpertrack %d\n", 145 pmp->pm_BytesPerSec, SecPerClust, 146 pmp->pm_SecPerTrack)); 147 error = EINVAL; 148 goto error_exit; 149 } 150 151 pmp->pm_flags = flags & MSDOSFSMNT_MNTOPT; 152 if (pmp->pm_flags & MSDOSFSMNT_NOWIN95) 153 pmp->pm_flags |= MSDOSFSMNT_SHORTNAME; 154 155 if (pmp->pm_Sectors == 0) { 156 pmp->pm_HiddenSects = getulong(b50->bpbHiddenSecs); 157 pmp->pm_HugeSectors = getulong(b50->bpbHugeSectors); 158 } else { 159 pmp->pm_HiddenSects = getushort(b33->bpbHiddenSecs); 160 pmp->pm_HugeSectors = pmp->pm_Sectors; 161 } 162 163 if (pmp->pm_RootDirEnts == 0) { 164 unsigned short vers = getushort(b710->bpbFSVers); 165 /* 166 * Some say that bsBootSectSig[23] must be zero, but 167 * Windows does not require this and some digital cameras 168 * do not set these to zero. Therefore, do not insist. 169 */ 170 if (pmp->pm_Sectors || pmp->pm_FATsecs || vers) { 171 DPRINTF(("sectors %d fatsecs %lu vers %d\n", 172 pmp->pm_Sectors, pmp->pm_FATsecs, vers)); 173 error = EINVAL; 174 goto error_exit; 175 } 176 pmp->pm_fatmask = FAT32_MASK; 177 pmp->pm_fatmult = 4; 178 pmp->pm_fatdiv = 1; 179 pmp->pm_FATsecs = getulong(b710->bpbBigFATsecs); 180 181 /* mirrorring is enabled if the FATMIRROR bit is not set */ 182 if ((getushort(b710->bpbExtFlags) & FATMIRROR) == 0) 183 pmp->pm_flags |= MSDOSFS_FATMIRROR; 184 else 185 pmp->pm_curfat = getushort(b710->bpbExtFlags) & FATNUM; 186 } else 187 pmp->pm_flags |= MSDOSFS_FATMIRROR; 188 189 /* Check that fs has nonzero FAT size */ 190 if (pmp->pm_FATsecs == 0) { 191 DPRINTF(("FATsecs is 0\n")); 192 error = EINVAL; 193 goto error_exit; 194 } 195 196 pmp->pm_fatblk = pmp->pm_ResSectors; 197 if (FAT32(pmp)) { 198 pmp->pm_rootdirblk = getulong(b710->bpbRootClust); 199 pmp->pm_firstcluster = pmp->pm_fatblk 200 + (pmp->pm_FATs * pmp->pm_FATsecs); 201 pmp->pm_fsinfo = getushort(b710->bpbFSInfo); 202 } else { 203 pmp->pm_rootdirblk = pmp->pm_fatblk + 204 (pmp->pm_FATs * pmp->pm_FATsecs); 205 pmp->pm_rootdirsize = (pmp->pm_RootDirEnts * sizeof(struct direntry) 206 + pmp->pm_BytesPerSec - 1) 207 / pmp->pm_BytesPerSec;/* in sectors */ 208 pmp->pm_firstcluster = pmp->pm_rootdirblk + pmp->pm_rootdirsize; 209 } 210 211 pmp->pm_nmbrofclusters = (pmp->pm_HugeSectors - pmp->pm_firstcluster) / 212 SecPerClust; 213 pmp->pm_maxcluster = pmp->pm_nmbrofclusters + 1; 214 pmp->pm_fatsize = pmp->pm_FATsecs * pmp->pm_BytesPerSec; 215 216 if (pmp->pm_fatmask == 0) { 217 if (pmp->pm_maxcluster 218 <= ((CLUST_RSRVD - CLUST_FIRST) & FAT12_MASK)) { 219 /* 220 * This will usually be a floppy disk. This size makes 221 * sure that one FAT entry will not be split across 222 * multiple blocks. 223 */ 224 pmp->pm_fatmask = FAT12_MASK; 225 pmp->pm_fatmult = 3; 226 pmp->pm_fatdiv = 2; 227 } else { 228 pmp->pm_fatmask = FAT16_MASK; 229 pmp->pm_fatmult = 2; 230 pmp->pm_fatdiv = 1; 231 } 232 } 233 if (FAT12(pmp)) 234 pmp->pm_fatblocksize = 3 * pmp->pm_BytesPerSec; 235 else 236 pmp->pm_fatblocksize = MAXBSIZE; 237 238 pmp->pm_fatblocksec = pmp->pm_fatblocksize / pmp->pm_BytesPerSec; 239 pmp->pm_bnshift = ffs(pmp->pm_BytesPerSec) - 1; 240 241 /* 242 * Compute mask and shift value for isolating cluster relative byte 243 * offsets and cluster numbers from a file offset. 244 */ 245 pmp->pm_bpcluster = SecPerClust * pmp->pm_BytesPerSec; 246 pmp->pm_crbomask = pmp->pm_bpcluster - 1; 247 pmp->pm_cnshift = ffs(pmp->pm_bpcluster) - 1; 248 249 DPRINTF(("%s(fatmask=%lu, fatmult=%u, fatdiv=%u, fatblocksize=%lu, " 250 "fatblocksec=%lu, bnshift=%lu, pbcluster=%lu, crbomask=%lu, " 251 "cnshift=%lu)\n", 252 __func__, pmp->pm_fatmask, pmp->pm_fatmult, pmp->pm_fatdiv, 253 pmp->pm_fatblocksize, pmp->pm_fatblocksec, pmp->pm_bnshift, 254 pmp->pm_bpcluster, pmp->pm_crbomask, pmp->pm_cnshift)); 255 /* 256 * Check for valid cluster size 257 * must be a power of 2 258 */ 259 if (pmp->pm_bpcluster ^ (1 << pmp->pm_cnshift)) { 260 DPRINTF(("bpcluster %lu cnshift %lu\n", 261 pmp->pm_bpcluster, pmp->pm_cnshift)); 262 error = EINVAL; 263 goto error_exit; 264 } 265 266 /* 267 * Release the bootsector buffer. 268 */ 269 brelse(bp, BC_AGE); 270 bp = NULL; 271 272 /* 273 * Check FSInfo. 274 */ 275 if (pmp->pm_fsinfo) { 276 struct fsinfo *fp; 277 278 /* 279 * XXX If the fsinfo block is stored on media with 280 * 2KB or larger sectors, is the fsinfo structure 281 * padded at the end or in the middle? 282 */ 283 DPRINTF(("%s(bread %lu)\n", __func__, 284 (unsigned long)de_bn2kb(pmp, pmp->pm_fsinfo))); 285 if ((error = bread(devvp, de_bn2kb(pmp, pmp->pm_fsinfo), 286 pmp->pm_BytesPerSec, 0, &bp)) != 0) 287 goto error_exit; 288 fp = (struct fsinfo *)bp->b_data; 289 if (!memcmp(fp->fsisig1, "RRaA", 4) 290 && !memcmp(fp->fsisig2, "rrAa", 4) 291 && !memcmp(fp->fsisig3, "\0\0\125\252", 4) 292 && !memcmp(fp->fsisig4, "\0\0\125\252", 4)) 293 pmp->pm_nxtfree = getulong(fp->fsinxtfree); 294 else 295 pmp->pm_fsinfo = 0; 296 brelse(bp, 0); 297 bp = NULL; 298 } 299 300 /* 301 * Check and validate (or perhaps invalidate?) the fsinfo structure? 302 * XXX 303 */ 304 if (pmp->pm_fsinfo) { 305 if ((pmp->pm_nxtfree == 0xffffffffUL) || 306 (pmp->pm_nxtfree > pmp->pm_maxcluster)) 307 pmp->pm_fsinfo = 0; 308 } 309 310 /* 311 * Allocate memory for the bitmap of allocated clusters, and then 312 * fill it in. 313 */ 314 pmp->pm_inusemap = ecalloc(sizeof(*pmp->pm_inusemap), 315 ((pmp->pm_maxcluster + N_INUSEBITS) / N_INUSEBITS)); 316 /* 317 * fillinusemap() needs pm_devvp. 318 */ 319 pmp->pm_dev = 0; 320 pmp->pm_devvp = devvp; 321 322 /* 323 * Have the inuse map filled in. 324 */ 325 if ((error = fillinusemap(pmp)) != 0) { 326 DPRINTF(("fillinusemap %d\n", error)); 327 goto error_exit; 328 } 329 330 /* 331 * Finish up. 332 */ 333 if (ronly) 334 pmp->pm_flags |= MSDOSFSMNT_RONLY; 335 else 336 pmp->pm_fmod = 1; 337 338 return pmp; 339 340 error_exit: 341 if (bp) 342 brelse(bp, BC_AGE); 343 if (pmp) { 344 if (pmp->pm_inusemap) 345 free(pmp->pm_inusemap); 346 free(pmp); 347 } 348 errno = error; 349 return NULL; 350 } 351 352 int 353 msdosfs_root(struct msdosfsmount *pmp, struct mkfsvnode *vp) { 354 struct denode *ndep; 355 int error; 356 357 *vp = *pmp->pm_devvp; 358 if ((error = deget(pmp, MSDOSFSROOT, MSDOSFSROOT_OFS, &ndep)) != 0) { 359 errno = error; 360 return -1; 361 } 362 vp->v_data = ndep; 363 return 0; 364 } 365