msdosfs_vfsops.c revision 1.5
1 /*- 2 * Copyright (C) 1994, 1995, 1997 Wolfgang Solfrank. 3 * Copyright (C) 1994, 1995, 1997 TooLs GmbH. 4 * All rights reserved. 5 * Original code by Paul Popelka (paulp (at) uts.amdahl.com) (see below). 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 TooLs GmbH. 18 * 4. The name of TooLs GmbH may not be used to endorse or promote products 19 * derived from this software without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``AS IS'' AND ANY EXPRESS OR 22 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 23 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 24 * IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 25 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 26 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; 27 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 28 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR 29 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF 30 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 31 */ 32 /* 33 * Written by Paul Popelka (paulp (at) uts.amdahl.com) 34 * 35 * You can do anything you want with this software, just don't say you wrote 36 * it, and don't remove this notice. 37 * 38 * This software is provided "as is". 39 * 40 * The author supplies this software to be publicly redistributed on the 41 * understanding that the author is not responsible for the correct 42 * functioning of this software in any circumstances and is not liable for 43 * any damages caused by this software. 44 * 45 * October 1992 46 */ 47 48 #if HAVE_NBTOOL_CONFIG_H 49 #include "nbtool_config.h" 50 #endif 51 52 #include <sys/cdefs.h> 53 __KERNEL_RCSID(0, "$NetBSD: msdosfs_vfsops.c,v 1.5 2013/01/27 20:05:46 christos Exp $"); 54 55 #include <sys/param.h> 56 57 #include <ffs/buf.h> 58 59 #include <fs/msdosfs/bpb.h> 60 #include <fs/msdosfs/bootsect.h> 61 #include <fs/msdosfs/direntry.h> 62 #include <fs/msdosfs/denode.h> 63 #include <fs/msdosfs/msdosfsmount.h> 64 #include <fs/msdosfs/fat.h> 65 66 #include <stdio.h> 67 #include <errno.h> 68 #include <stdlib.h> 69 #include <string.h> 70 71 #include "makefs.h" 72 #include "msdos.h" 73 #include "mkfs_msdos.h" 74 75 #ifdef MSDOSFS_DEBUG 76 #define DPRINTF(a) printf a 77 #else 78 #define DPRINTF(a) 79 #endif 80 81 struct msdosfsmount * 82 msdosfs_mount(struct vnode *devvp, int flags) 83 { 84 struct msdosfsmount *pmp = NULL; 85 struct buf *bp; 86 union bootsector *bsp; 87 struct byte_bpb33 *b33; 88 struct byte_bpb50 *b50; 89 struct byte_bpb710 *b710; 90 uint8_t SecPerClust; 91 int ronly = 0, error, tmp; 92 int bsize; 93 struct msdos_options *m = devvp->fs; 94 uint64_t psize = m->create_size; 95 unsigned secsize = 512; 96 97 DPRINTF(("%s(bread 0)\n", __func__)); 98 if ((error = bread(devvp, 0, secsize, NULL, 0, &bp)) != 0) 99 goto error_exit; 100 101 bsp = (union bootsector *)bp->b_data; 102 b33 = (struct byte_bpb33 *)bsp->bs33.bsBPB; 103 b50 = (struct byte_bpb50 *)bsp->bs50.bsBPB; 104 b710 = (struct byte_bpb710 *)bsp->bs710.bsBPB; 105 106 if (!(flags & MSDOSFSMNT_GEMDOSFS)) { 107 if (bsp->bs50.bsBootSectSig0 != BOOTSIG0 108 || bsp->bs50.bsBootSectSig1 != BOOTSIG1) { 109 DPRINTF(("bootsig0 %d bootsig1 %d\n", 110 bsp->bs50.bsBootSectSig0, 111 bsp->bs50.bsBootSectSig1)); 112 error = EINVAL; 113 goto error_exit; 114 } 115 bsize = 0; 116 } else 117 bsize = 512; 118 119 pmp = calloc(1, sizeof *pmp); 120 if (pmp == NULL) 121 goto error_exit; 122 123 /* 124 * Compute several useful quantities from the bpb in the 125 * bootsector. Copy in the dos 5 variant of the bpb then fix up 126 * the fields that are different between dos 5 and dos 3.3. 127 */ 128 SecPerClust = b50->bpbSecPerClust; 129 pmp->pm_BytesPerSec = getushort(b50->bpbBytesPerSec); 130 pmp->pm_ResSectors = getushort(b50->bpbResSectors); 131 pmp->pm_FATs = b50->bpbFATs; 132 pmp->pm_RootDirEnts = getushort(b50->bpbRootDirEnts); 133 pmp->pm_Sectors = getushort(b50->bpbSectors); 134 pmp->pm_FATsecs = getushort(b50->bpbFATsecs); 135 pmp->pm_SecPerTrack = getushort(b50->bpbSecPerTrack); 136 pmp->pm_Heads = getushort(b50->bpbHeads); 137 pmp->pm_Media = b50->bpbMedia; 138 139 DPRINTF(("%s(BytesPerSec=%u, ResSectors=%u, FATs=%d, RootDirEnts=%u, " 140 "Sectors=%u, FATsecs=%lu, SecPerTrack=%u, Heads=%u, Media=%u)\n", 141 __func__, pmp->pm_BytesPerSec, pmp->pm_ResSectors, pmp->pm_FATs, 142 pmp->pm_RootDirEnts, pmp->pm_Sectors, pmp->pm_FATsecs, 143 pmp->pm_SecPerTrack, pmp->pm_Heads, pmp->pm_Media)); 144 if (!(flags & MSDOSFSMNT_GEMDOSFS)) { 145 /* XXX - We should probably check more values here */ 146 if (!pmp->pm_BytesPerSec || !SecPerClust 147 || pmp->pm_SecPerTrack > 63) { 148 DPRINTF(("bytespersec %d secperclust %d " 149 "secpertrack %d\n", 150 pmp->pm_BytesPerSec, SecPerClust, 151 pmp->pm_SecPerTrack)); 152 error = EINVAL; 153 goto error_exit; 154 } 155 } 156 157 if (pmp->pm_Sectors == 0) { 158 pmp->pm_HiddenSects = getulong(b50->bpbHiddenSecs); 159 pmp->pm_HugeSectors = getulong(b50->bpbHugeSectors); 160 } else { 161 pmp->pm_HiddenSects = getushort(b33->bpbHiddenSecs); 162 pmp->pm_HugeSectors = pmp->pm_Sectors; 163 } 164 165 if (pmp->pm_RootDirEnts == 0) { 166 unsigned short vers = getushort(b710->bpbFSVers); 167 /* 168 * Some say that bsBootSectSig[23] must be zero, but 169 * Windows does not require this and some digital cameras 170 * do not set these to zero. Therefore, do not insist. 171 */ 172 if (pmp->pm_Sectors || pmp->pm_FATsecs || vers) { 173 DPRINTF(("sectors %d fatsecs %lu vers %d\n", 174 pmp->pm_Sectors, pmp->pm_FATsecs, vers)); 175 error = EINVAL; 176 goto error_exit; 177 } 178 pmp->pm_fatmask = FAT32_MASK; 179 pmp->pm_fatmult = 4; 180 pmp->pm_fatdiv = 1; 181 pmp->pm_FATsecs = getulong(b710->bpbBigFATsecs); 182 183 /* mirrorring is enabled if the FATMIRROR bit is not set */ 184 if ((getushort(b710->bpbExtFlags) & FATMIRROR) == 0) 185 pmp->pm_flags |= MSDOSFS_FATMIRROR; 186 else 187 pmp->pm_curfat = getushort(b710->bpbExtFlags) & FATNUM; 188 } else 189 pmp->pm_flags |= MSDOSFS_FATMIRROR; 190 191 if (flags & MSDOSFSMNT_GEMDOSFS) { 192 if (FAT32(pmp)) { 193 DPRINTF(("FAT32 for GEMDOS\n")); 194 /* 195 * GEMDOS doesn't know FAT32. 196 */ 197 error = EINVAL; 198 goto error_exit; 199 } 200 201 /* 202 * Check a few values (could do some more): 203 * - logical sector size: power of 2, >= block size 204 * - sectors per cluster: power of 2, >= 1 205 * - number of sectors: >= 1, <= size of partition 206 */ 207 if ( (SecPerClust == 0) 208 || (SecPerClust & (SecPerClust - 1)) 209 || (pmp->pm_BytesPerSec < bsize) 210 || (pmp->pm_BytesPerSec & (pmp->pm_BytesPerSec - 1)) 211 || (pmp->pm_HugeSectors == 0) 212 || (pmp->pm_HugeSectors * (pmp->pm_BytesPerSec / bsize) 213 > psize)) { 214 DPRINTF(("consistency checks for GEMDOS\n")); 215 error = EINVAL; 216 goto error_exit; 217 } 218 /* 219 * XXX - Many parts of the msdosfs driver seem to assume that 220 * the number of bytes per logical sector (BytesPerSec) will 221 * always be the same as the number of bytes per disk block 222 * Let's pretend it is. 223 */ 224 tmp = pmp->pm_BytesPerSec / bsize; 225 pmp->pm_BytesPerSec = bsize; 226 pmp->pm_HugeSectors *= tmp; 227 pmp->pm_HiddenSects *= tmp; 228 pmp->pm_ResSectors *= tmp; 229 pmp->pm_Sectors *= tmp; 230 pmp->pm_FATsecs *= tmp; 231 SecPerClust *= tmp; 232 } 233 234 /* Check that fs has nonzero FAT size */ 235 if (pmp->pm_FATsecs == 0) { 236 DPRINTF(("FATsecs is 0\n")); 237 error = EINVAL; 238 goto error_exit; 239 } 240 241 pmp->pm_fatblk = pmp->pm_ResSectors; 242 if (FAT32(pmp)) { 243 pmp->pm_rootdirblk = getulong(b710->bpbRootClust); 244 pmp->pm_firstcluster = pmp->pm_fatblk 245 + (pmp->pm_FATs * pmp->pm_FATsecs); 246 pmp->pm_fsinfo = getushort(b710->bpbFSInfo); 247 } else { 248 pmp->pm_rootdirblk = pmp->pm_fatblk + 249 (pmp->pm_FATs * pmp->pm_FATsecs); 250 pmp->pm_rootdirsize = (pmp->pm_RootDirEnts * sizeof(struct direntry) 251 + pmp->pm_BytesPerSec - 1) 252 / pmp->pm_BytesPerSec;/* in sectors */ 253 pmp->pm_firstcluster = pmp->pm_rootdirblk + pmp->pm_rootdirsize; 254 } 255 256 pmp->pm_nmbrofclusters = (pmp->pm_HugeSectors - pmp->pm_firstcluster) / 257 SecPerClust; 258 pmp->pm_maxcluster = pmp->pm_nmbrofclusters + 1; 259 pmp->pm_fatsize = pmp->pm_FATsecs * pmp->pm_BytesPerSec; 260 261 if (flags & MSDOSFSMNT_GEMDOSFS) { 262 if (pmp->pm_nmbrofclusters <= (0xff0 - 2)) { 263 pmp->pm_fatmask = FAT12_MASK; 264 pmp->pm_fatmult = 3; 265 pmp->pm_fatdiv = 2; 266 } else { 267 pmp->pm_fatmask = FAT16_MASK; 268 pmp->pm_fatmult = 2; 269 pmp->pm_fatdiv = 1; 270 } 271 } else if (pmp->pm_fatmask == 0) { 272 if (pmp->pm_maxcluster 273 <= ((CLUST_RSRVD - CLUST_FIRST) & FAT12_MASK)) { 274 /* 275 * This will usually be a floppy disk. This size makes 276 * sure that one FAT entry will not be split across 277 * multiple blocks. 278 */ 279 pmp->pm_fatmask = FAT12_MASK; 280 pmp->pm_fatmult = 3; 281 pmp->pm_fatdiv = 2; 282 } else { 283 pmp->pm_fatmask = FAT16_MASK; 284 pmp->pm_fatmult = 2; 285 pmp->pm_fatdiv = 1; 286 } 287 } 288 if (FAT12(pmp)) 289 pmp->pm_fatblocksize = 3 * pmp->pm_BytesPerSec; 290 else 291 pmp->pm_fatblocksize = MAXBSIZE; 292 293 pmp->pm_fatblocksec = pmp->pm_fatblocksize / pmp->pm_BytesPerSec; 294 pmp->pm_bnshift = ffs(pmp->pm_BytesPerSec) - 1; 295 296 /* 297 * Compute mask and shift value for isolating cluster relative byte 298 * offsets and cluster numbers from a file offset. 299 */ 300 pmp->pm_bpcluster = SecPerClust * pmp->pm_BytesPerSec; 301 pmp->pm_crbomask = pmp->pm_bpcluster - 1; 302 pmp->pm_cnshift = ffs(pmp->pm_bpcluster) - 1; 303 304 DPRINTF(("%s(fatmask=%lu, fatmult=%u, fatdiv=%u, fatblocksize=%lu, " 305 "fatblocksec=%lu, bnshift=%lu, pbcluster=%lu, crbomask=%lu, " 306 "cnshift=%lu)\n", 307 __func__, pmp->pm_fatmask, pmp->pm_fatmult, pmp->pm_fatdiv, 308 pmp->pm_fatblocksize, pmp->pm_fatblocksec, pmp->pm_bnshift, 309 pmp->pm_bpcluster, pmp->pm_crbomask, pmp->pm_cnshift)); 310 /* 311 * Check for valid cluster size 312 * must be a power of 2 313 */ 314 if (pmp->pm_bpcluster ^ (1 << pmp->pm_cnshift)) { 315 DPRINTF(("bpcluster %lu cnshift %lu\n", 316 pmp->pm_bpcluster, pmp->pm_cnshift)); 317 error = EINVAL; 318 goto error_exit; 319 } 320 321 /* 322 * Release the bootsector buffer. 323 */ 324 brelse(bp, BC_AGE); 325 bp = NULL; 326 327 /* 328 * Check FSInfo. 329 */ 330 if (pmp->pm_fsinfo) { 331 struct fsinfo *fp; 332 333 /* 334 * XXX If the fsinfo block is stored on media with 335 * 2KB or larger sectors, is the fsinfo structure 336 * padded at the end or in the middle? 337 */ 338 DPRINTF(("%s(bread %lu)\n", __func__, 339 (unsigned long)de_bn2kb(pmp, pmp->pm_fsinfo))); 340 if ((error = bread(devvp, de_bn2kb(pmp, pmp->pm_fsinfo), 341 pmp->pm_BytesPerSec, NULL, 0, &bp)) != 0) 342 goto error_exit; 343 fp = (struct fsinfo *)bp->b_data; 344 if (!memcmp(fp->fsisig1, "RRaA", 4) 345 && !memcmp(fp->fsisig2, "rrAa", 4) 346 && !memcmp(fp->fsisig3, "\0\0\125\252", 4) 347 && !memcmp(fp->fsisig4, "\0\0\125\252", 4)) 348 pmp->pm_nxtfree = getulong(fp->fsinxtfree); 349 else 350 pmp->pm_fsinfo = 0; 351 brelse(bp, 0); 352 bp = NULL; 353 } 354 355 /* 356 * Check and validate (or perhaps invalidate?) the fsinfo structure? 357 * XXX 358 */ 359 if (pmp->pm_fsinfo) { 360 if ((pmp->pm_nxtfree == 0xffffffffUL) || 361 (pmp->pm_nxtfree > pmp->pm_maxcluster)) 362 pmp->pm_fsinfo = 0; 363 } 364 365 /* 366 * Allocate memory for the bitmap of allocated clusters, and then 367 * fill it in. 368 */ 369 pmp->pm_inusemap = calloc(sizeof(*pmp->pm_inusemap), 370 ((pmp->pm_maxcluster + N_INUSEBITS) / N_INUSEBITS)); 371 if (pmp->pm_inusemap == NULL) 372 goto error_exit; 373 374 /* 375 * fillinusemap() needs pm_devvp. 376 */ 377 pmp->pm_dev = 0; 378 pmp->pm_devvp = devvp; 379 380 /* 381 * Have the inuse map filled in. 382 */ 383 if ((error = fillinusemap(pmp)) != 0) { 384 DPRINTF(("fillinusemap %d\n", error)); 385 goto error_exit; 386 } 387 388 /* 389 * Finish up. 390 */ 391 if (ronly) 392 pmp->pm_flags |= MSDOSFSMNT_RONLY; 393 else 394 pmp->pm_fmod = 1; 395 396 /* 397 * If we ever do quotas for DOS filesystems this would be a place 398 * to fill in the info in the msdosfsmount structure. You dolt, 399 * quotas on dos filesystems make no sense because files have no 400 * owners on dos filesystems. of course there is some empty space 401 * in the directory entry where we could put uid's and gid's. 402 */ 403 404 return pmp; 405 406 error_exit: 407 if (bp) 408 brelse(bp, BC_AGE); 409 if (pmp) { 410 if (pmp->pm_inusemap) 411 free(pmp->pm_inusemap); 412 free(pmp); 413 } 414 errno = error; 415 return pmp; 416 } 417 418 int 419 msdosfs_root(struct msdosfsmount *pmp, struct vnode *vp) { 420 struct denode *ndep; 421 int error; 422 423 *vp = *pmp->pm_devvp; 424 if ((error = deget(pmp, MSDOSFSROOT, MSDOSFSROOT_OFS, &ndep)) != 0) { 425 errno = error; 426 return -1; 427 } 428 vp->v_data = ndep; 429 return 0; 430 } 431
Indexes created Mon Sep 29 21:09:56 GMT 2025