msdosfs_vfsops.c revision 1.11
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 1.11 2018/01/27 02:07:33 sevan 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 #include <util.h> 71 #include <strings.h> 72 73 #include "makefs.h" 74 #include "msdos.h" 75 #include "mkfs_msdos.h" 76 77 #ifdef MSDOSFS_DEBUG 78 #define DPRINTF(a) printf a 79 #else 80 #define DPRINTF(a) 81 #endif 82 83 struct msdosfsmount * 84 msdosfs_mount(struct vnode *devvp, int flags) 85 { 86 struct msdosfsmount *pmp = NULL; 87 struct buf *bp; 88 union bootsector *bsp; 89 struct byte_bpb33 *b33; 90 struct byte_bpb50 *b50; 91 struct byte_bpb710 *b710; 92 uint8_t SecPerClust; 93 int ronly = 0, error, tmp; 94 int bsize; 95 struct msdos_options *m = devvp->fs->fs_specific; 96 uint64_t psize = m->create_size; 97 unsigned secsize = 512; 98 99 DPRINTF(("%s(bread 0)\n", __func__)); 100 if ((error = bread(devvp, 0, secsize, 0, &bp)) != 0) 101 goto error_exit; 102 103 bsp = (union bootsector *)bp->b_data; 104 b33 = (struct byte_bpb33 *)bsp->bs33.bsBPB; 105 b50 = (struct byte_bpb50 *)bsp->bs50.bsBPB; 106 b710 = (struct byte_bpb710 *)bsp->bs710.bsBPB; 107 108 if (!(flags & MSDOSFSMNT_GEMDOSFS)) { 109 if (bsp->bs50.bsBootSectSig0 != BOOTSIG0 110 || bsp->bs50.bsBootSectSig1 != BOOTSIG1) { 111 DPRINTF(("bootsig0 %d bootsig1 %d\n", 112 bsp->bs50.bsBootSectSig0, 113 bsp->bs50.bsBootSectSig1)); 114 error = EINVAL; 115 goto error_exit; 116 } 117 bsize = 0; 118 } else 119 bsize = 512; 120 121 pmp = ecalloc(1, sizeof *pmp); 122 /* 123 * Compute several useful quantities from the bpb in the 124 * bootsector. Copy in the dos 5 variant of the bpb then fix up 125 * the fields that are different between dos 5 and dos 3.3. 126 */ 127 SecPerClust = b50->bpbSecPerClust; 128 pmp->pm_BytesPerSec = getushort(b50->bpbBytesPerSec); 129 pmp->pm_ResSectors = getushort(b50->bpbResSectors); 130 pmp->pm_FATs = b50->bpbFATs; 131 pmp->pm_RootDirEnts = getushort(b50->bpbRootDirEnts); 132 pmp->pm_Sectors = getushort(b50->bpbSectors); 133 pmp->pm_FATsecs = getushort(b50->bpbFATsecs); 134 pmp->pm_SecPerTrack = getushort(b50->bpbSecPerTrack); 135 pmp->pm_Heads = getushort(b50->bpbHeads); 136 pmp->pm_Media = b50->bpbMedia; 137 138 DPRINTF(("%s(BytesPerSec=%u, ResSectors=%u, FATs=%d, RootDirEnts=%u, " 139 "Sectors=%u, FATsecs=%lu, SecPerTrack=%u, Heads=%u, Media=%u)\n", 140 __func__, pmp->pm_BytesPerSec, pmp->pm_ResSectors, pmp->pm_FATs, 141 pmp->pm_RootDirEnts, pmp->pm_Sectors, pmp->pm_FATsecs, 142 pmp->pm_SecPerTrack, pmp->pm_Heads, pmp->pm_Media)); 143 if (!(flags & MSDOSFSMNT_GEMDOSFS)) { 144 /* XXX - We should probably check more values here */ 145 if (!pmp->pm_BytesPerSec || !SecPerClust 146 || pmp->pm_SecPerTrack > 63) { 147 DPRINTF(("bytespersec %d secperclust %d " 148 "secpertrack %d\n", 149 pmp->pm_BytesPerSec, SecPerClust, 150 pmp->pm_SecPerTrack)); 151 error = EINVAL; 152 goto error_exit; 153 } 154 } 155 156 pmp->pm_flags = flags & MSDOSFSMNT_MNTOPT; 157 if (pmp->pm_flags & MSDOSFSMNT_GEMDOSFS) 158 pmp->pm_flags |= MSDOSFSMNT_NOWIN95; 159 if (pmp->pm_flags & MSDOSFSMNT_NOWIN95) 160 pmp->pm_flags |= MSDOSFSMNT_SHORTNAME; 161 162 if (pmp->pm_Sectors == 0) { 163 pmp->pm_HiddenSects = getulong(b50->bpbHiddenSecs); 164 pmp->pm_HugeSectors = getulong(b50->bpbHugeSectors); 165 } else { 166 pmp->pm_HiddenSects = getushort(b33->bpbHiddenSecs); 167 pmp->pm_HugeSectors = pmp->pm_Sectors; 168 } 169 170 if (pmp->pm_RootDirEnts == 0) { 171 unsigned short vers = getushort(b710->bpbFSVers); 172 /* 173 * Some say that bsBootSectSig[23] must be zero, but 174 * Windows does not require this and some digital cameras 175 * do not set these to zero. Therefore, do not insist. 176 */ 177 if (pmp->pm_Sectors || pmp->pm_FATsecs || vers) { 178 DPRINTF(("sectors %d fatsecs %lu vers %d\n", 179 pmp->pm_Sectors, pmp->pm_FATsecs, vers)); 180 error = EINVAL; 181 goto error_exit; 182 } 183 pmp->pm_fatmask = FAT32_MASK; 184 pmp->pm_fatmult = 4; 185 pmp->pm_fatdiv = 1; 186 pmp->pm_FATsecs = getulong(b710->bpbBigFATsecs); 187 188 /* mirrorring is enabled if the FATMIRROR bit is not set */ 189 if ((getushort(b710->bpbExtFlags) & FATMIRROR) == 0) 190 pmp->pm_flags |= MSDOSFS_FATMIRROR; 191 else 192 pmp->pm_curfat = getushort(b710->bpbExtFlags) & FATNUM; 193 } else 194 pmp->pm_flags |= MSDOSFS_FATMIRROR; 195 196 if (flags & MSDOSFSMNT_GEMDOSFS) { 197 if (FAT32(pmp)) { 198 DPRINTF(("FAT32 for GEMDOS\n")); 199 /* 200 * GEMDOS doesn't know FAT32. 201 */ 202 error = EINVAL; 203 goto error_exit; 204 } 205 206 /* 207 * Check a few values (could do some more): 208 * - logical sector size: power of 2, >= block size 209 * - sectors per cluster: power of 2, >= 1 210 * - number of sectors: >= 1, <= size of partition 211 */ 212 if ( (SecPerClust == 0) 213 || (SecPerClust & (SecPerClust - 1)) 214 || (pmp->pm_BytesPerSec < bsize) 215 || (pmp->pm_BytesPerSec & (pmp->pm_BytesPerSec - 1)) 216 || (pmp->pm_HugeSectors == 0) 217 || (pmp->pm_HugeSectors * (pmp->pm_BytesPerSec / bsize) 218 > psize)) { 219 DPRINTF(("consistency checks for GEMDOS\n")); 220 error = EINVAL; 221 goto error_exit; 222 } 223 /* 224 * XXX - Many parts of the msdosfs driver seem to assume that 225 * the number of bytes per logical sector (BytesPerSec) will 226 * always be the same as the number of bytes per disk block 227 * Let's pretend it is. 228 */ 229 tmp = pmp->pm_BytesPerSec / bsize; 230 pmp->pm_BytesPerSec = bsize; 231 pmp->pm_HugeSectors *= tmp; 232 pmp->pm_HiddenSects *= tmp; 233 pmp->pm_ResSectors *= tmp; 234 pmp->pm_Sectors *= tmp; 235 pmp->pm_FATsecs *= tmp; 236 SecPerClust *= tmp; 237 } 238 239 /* Check that fs has nonzero FAT size */ 240 if (pmp->pm_FATsecs == 0) { 241 DPRINTF(("FATsecs is 0\n")); 242 error = EINVAL; 243 goto error_exit; 244 } 245 246 pmp->pm_fatblk = pmp->pm_ResSectors; 247 if (FAT32(pmp)) { 248 pmp->pm_rootdirblk = getulong(b710->bpbRootClust); 249 pmp->pm_firstcluster = pmp->pm_fatblk 250 + (pmp->pm_FATs * pmp->pm_FATsecs); 251 pmp->pm_fsinfo = getushort(b710->bpbFSInfo); 252 } else { 253 pmp->pm_rootdirblk = pmp->pm_fatblk + 254 (pmp->pm_FATs * pmp->pm_FATsecs); 255 pmp->pm_rootdirsize = (pmp->pm_RootDirEnts * sizeof(struct direntry) 256 + pmp->pm_BytesPerSec - 1) 257 / pmp->pm_BytesPerSec;/* in sectors */ 258 pmp->pm_firstcluster = pmp->pm_rootdirblk + pmp->pm_rootdirsize; 259 } 260 261 pmp->pm_nmbrofclusters = (pmp->pm_HugeSectors - pmp->pm_firstcluster) / 262 SecPerClust; 263 pmp->pm_maxcluster = pmp->pm_nmbrofclusters + 1; 264 pmp->pm_fatsize = pmp->pm_FATsecs * pmp->pm_BytesPerSec; 265 266 if (flags & MSDOSFSMNT_GEMDOSFS) { 267 if (pmp->pm_nmbrofclusters <= (0xff0 - 2)) { 268 pmp->pm_fatmask = FAT12_MASK; 269 pmp->pm_fatmult = 3; 270 pmp->pm_fatdiv = 2; 271 } else { 272 pmp->pm_fatmask = FAT16_MASK; 273 pmp->pm_fatmult = 2; 274 pmp->pm_fatdiv = 1; 275 } 276 } else if (pmp->pm_fatmask == 0) { 277 if (pmp->pm_maxcluster 278 <= ((CLUST_RSRVD - CLUST_FIRST) & FAT12_MASK)) { 279 /* 280 * This will usually be a floppy disk. This size makes 281 * sure that one FAT entry will not be split across 282 * multiple blocks. 283 */ 284 pmp->pm_fatmask = FAT12_MASK; 285 pmp->pm_fatmult = 3; 286 pmp->pm_fatdiv = 2; 287 } else { 288 pmp->pm_fatmask = FAT16_MASK; 289 pmp->pm_fatmult = 2; 290 pmp->pm_fatdiv = 1; 291 } 292 } 293 if (FAT12(pmp)) 294 pmp->pm_fatblocksize = 3 * pmp->pm_BytesPerSec; 295 else 296 pmp->pm_fatblocksize = MAXBSIZE; 297 298 pmp->pm_fatblocksec = pmp->pm_fatblocksize / pmp->pm_BytesPerSec; 299 pmp->pm_bnshift = ffs(pmp->pm_BytesPerSec) - 1; 300 301 /* 302 * Compute mask and shift value for isolating cluster relative byte 303 * offsets and cluster numbers from a file offset. 304 */ 305 pmp->pm_bpcluster = SecPerClust * pmp->pm_BytesPerSec; 306 pmp->pm_crbomask = pmp->pm_bpcluster - 1; 307 pmp->pm_cnshift = ffs(pmp->pm_bpcluster) - 1; 308 309 DPRINTF(("%s(fatmask=%lu, fatmult=%u, fatdiv=%u, fatblocksize=%lu, " 310 "fatblocksec=%lu, bnshift=%lu, pbcluster=%lu, crbomask=%lu, " 311 "cnshift=%lu)\n", 312 __func__, pmp->pm_fatmask, pmp->pm_fatmult, pmp->pm_fatdiv, 313 pmp->pm_fatblocksize, pmp->pm_fatblocksec, pmp->pm_bnshift, 314 pmp->pm_bpcluster, pmp->pm_crbomask, pmp->pm_cnshift)); 315 /* 316 * Check for valid cluster size 317 * must be a power of 2 318 */ 319 if (pmp->pm_bpcluster ^ (1 << pmp->pm_cnshift)) { 320 DPRINTF(("bpcluster %lu cnshift %lu\n", 321 pmp->pm_bpcluster, pmp->pm_cnshift)); 322 error = EINVAL; 323 goto error_exit; 324 } 325 326 /* 327 * Release the bootsector buffer. 328 */ 329 brelse(bp, BC_AGE); 330 bp = NULL; 331 332 /* 333 * Check FSInfo. 334 */ 335 if (pmp->pm_fsinfo) { 336 struct fsinfo *fp; 337 338 /* 339 * XXX If the fsinfo block is stored on media with 340 * 2KB or larger sectors, is the fsinfo structure 341 * padded at the end or in the middle? 342 */ 343 DPRINTF(("%s(bread %lu)\n", __func__, 344 (unsigned long)de_bn2kb(pmp, pmp->pm_fsinfo))); 345 if ((error = bread(devvp, de_bn2kb(pmp, pmp->pm_fsinfo), 346 pmp->pm_BytesPerSec, 0, &bp)) != 0) 347 goto error_exit; 348 fp = (struct fsinfo *)bp->b_data; 349 if (!memcmp(fp->fsisig1, "RRaA", 4) 350 && !memcmp(fp->fsisig2, "rrAa", 4) 351 && !memcmp(fp->fsisig3, "\0\0\125\252", 4) 352 && !memcmp(fp->fsisig4, "\0\0\125\252", 4)) 353 pmp->pm_nxtfree = getulong(fp->fsinxtfree); 354 else 355 pmp->pm_fsinfo = 0; 356 brelse(bp, 0); 357 bp = NULL; 358 } 359 360 /* 361 * Check and validate (or perhaps invalidate?) the fsinfo structure? 362 * XXX 363 */ 364 if (pmp->pm_fsinfo) { 365 if ((pmp->pm_nxtfree == 0xffffffffUL) || 366 (pmp->pm_nxtfree > pmp->pm_maxcluster)) 367 pmp->pm_fsinfo = 0; 368 } 369 370 /* 371 * Allocate memory for the bitmap of allocated clusters, and then 372 * fill it in. 373 */ 374 pmp->pm_inusemap = ecalloc(sizeof(*pmp->pm_inusemap), 375 ((pmp->pm_maxcluster + N_INUSEBITS) / N_INUSEBITS)); 376 /* 377 * fillinusemap() needs pm_devvp. 378 */ 379 pmp->pm_dev = 0; 380 pmp->pm_devvp = devvp; 381 382 /* 383 * Have the inuse map filled in. 384 */ 385 if ((error = fillinusemap(pmp)) != 0) { 386 DPRINTF(("fillinusemap %d\n", error)); 387 goto error_exit; 388 } 389 390 /* 391 * Finish up. 392 */ 393 if (ronly) 394 pmp->pm_flags |= MSDOSFSMNT_RONLY; 395 else 396 pmp->pm_fmod = 1; 397 398 /* 399 * If we ever do quotas for DOS filesystems this would be a place 400 * to fill in the info in the msdosfsmount structure. You dolt, 401 * quotas on dos filesystems make no sense because files have no 402 * owners on dos filesystems. of course there is some empty space 403 * in the directory entry where we could put uid's and gid's. 404 */ 405 406 return pmp; 407 408 error_exit: 409 if (bp) 410 brelse(bp, BC_AGE); 411 if (pmp) { 412 if (pmp->pm_inusemap) 413 free(pmp->pm_inusemap); 414 free(pmp); 415 } 416 errno = error; 417 return NULL; 418 } 419 420 int 421 msdosfs_root(struct msdosfsmount *pmp, struct vnode *vp) { 422 struct denode *ndep; 423 int error; 424 425 *vp = *pmp->pm_devvp; 426 if ((error = deget(pmp, MSDOSFSROOT, MSDOSFSROOT_OFS, &ndep)) != 0) { 427 errno = error; 428 return -1; 429 } 430 vp->v_data = ndep; 431 return 0; 432 } 433
Indexes created Mon Sep 29 21:09:56 GMT 2025