1 /*- 2 * SPDX-License-Identifier: BSD-4-Clause 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/cdefs.h> 51 /* $NetBSD: msdosfs_vfsops.c,v 1.10 2016/01/30 09:59:27 mlelstv Exp $ */ 52 __FBSDID("$FreeBSD$"); 53 54 #include <sys/param.h> 55 #include <sys/mount.h> 56 57 #include <errno.h> 58 #include <stdbool.h> 59 #include <stdio.h> 60 #include <string.h> 61 #include <stdlib.h> 62 #include <util.h> 63 64 #include "ffs/buf.h" 65 #include <fs/msdosfs/bootsect.h> 66 #include <fs/msdosfs/bpb.h> 67 #include "msdos/direntry.h" 68 #include <fs/msdosfs/denode.h> 69 #include <fs/msdosfs/fat.h> 70 #include <fs/msdosfs/msdosfsmount.h> 71 72 #include <mkfs_msdos.h> 73 74 #include "makefs.h" 75 #include "msdos.h" 76 77 78 79 struct msdosfsmount * 80 msdosfs_mount(struct vnode *devvp) 81 { 82 struct msdosfsmount *pmp = NULL; 83 struct buf *bp; 84 union bootsector *bsp; 85 struct byte_bpb33 *b33; 86 struct byte_bpb50 *b50; 87 struct byte_bpb710 *b710; 88 uint8_t SecPerClust; 89 int ronly = 0, error; 90 int bsize; 91 unsigned secsize = 512; 92 93 MSDOSFS_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 MSDOSFS_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 MSDOSFS_DPRINTF(("%s(BytesPerSec=%u, ResSectors=%u, FATs=%d, " 130 "RootDirEnts=%u, Sectors=%u, FATsecs=%lu, SecPerTrack=%u, " 131 "Heads=%u, Media=%u)\n", 132 __func__, pmp->pm_BytesPerSec, pmp->pm_ResSectors, 133 pmp->pm_FATs, pmp->pm_RootDirEnts, pmp->pm_Sectors, 134 pmp->pm_FATsecs, pmp->pm_SecPerTrack, pmp->pm_Heads, 135 pmp->pm_Media)); 136 137 /* XXX - We should probably check more values here */ 138 if (!pmp->pm_BytesPerSec || !SecPerClust 139 || pmp->pm_SecPerTrack > 63) { 140 MSDOSFS_DPRINTF(("bytespersec %d secperclust %d " 141 "secpertrack %d\n", pmp->pm_BytesPerSec, 142 SecPerClust, pmp->pm_SecPerTrack)); 143 error = EINVAL; 144 goto error_exit; 145 } 146 147 if (pmp->pm_Sectors == 0) { 148 pmp->pm_HiddenSects = getulong(b50->bpbHiddenSecs); 149 pmp->pm_HugeSectors = getulong(b50->bpbHugeSectors); 150 } else { 151 pmp->pm_HiddenSects = getushort(b33->bpbHiddenSecs); 152 pmp->pm_HugeSectors = pmp->pm_Sectors; 153 } 154 155 pmp->pm_flags = 0; 156 if (pmp->pm_RootDirEnts == 0) { 157 unsigned short vers = getushort(b710->bpbFSVers); 158 /* 159 * Some say that bsBootSectSig[23] must be zero, but 160 * Windows does not require this and some digital cameras 161 * do not set these to zero. Therefore, do not insist. 162 */ 163 if (pmp->pm_Sectors || pmp->pm_FATsecs || vers) { 164 MSDOSFS_DPRINTF(("sectors %d fatsecs %lu vers %d\n", 165 pmp->pm_Sectors, pmp->pm_FATsecs, vers)); 166 error = EINVAL; 167 goto error_exit; 168 } 169 pmp->pm_fatmask = FAT32_MASK; 170 pmp->pm_fatmult = 4; 171 pmp->pm_fatdiv = 1; 172 pmp->pm_FATsecs = getulong(b710->bpbBigFATsecs); 173 174 /* mirrorring is enabled if the FATMIRROR bit is not set */ 175 if ((getushort(b710->bpbExtFlags) & FATMIRROR) == 0) 176 pmp->pm_flags |= MSDOSFS_FATMIRROR; 177 else 178 pmp->pm_curfat = getushort(b710->bpbExtFlags) & FATNUM; 179 } else 180 pmp->pm_flags |= MSDOSFS_FATMIRROR; 181 182 /* Check that fs has nonzero FAT size */ 183 if (pmp->pm_FATsecs == 0) { 184 MSDOSFS_DPRINTF(("FATsecs is 0\n")); 185 error = EINVAL; 186 goto error_exit; 187 } 188 189 pmp->pm_fatblk = pmp->pm_ResSectors; 190 if (FAT32(pmp)) { 191 pmp->pm_rootdirblk = getulong(b710->bpbRootClust); 192 pmp->pm_firstcluster = pmp->pm_fatblk 193 + (pmp->pm_FATs * pmp->pm_FATsecs); 194 pmp->pm_fsinfo = getushort(b710->bpbFSInfo); 195 } else { 196 pmp->pm_rootdirblk = pmp->pm_fatblk + 197 (pmp->pm_FATs * pmp->pm_FATsecs); 198 pmp->pm_rootdirsize = (pmp->pm_RootDirEnts * sizeof(struct direntry) 199 + pmp->pm_BytesPerSec - 1) 200 / pmp->pm_BytesPerSec;/* in sectors */ 201 pmp->pm_firstcluster = pmp->pm_rootdirblk + pmp->pm_rootdirsize; 202 } 203 204 pmp->pm_maxcluster = ((pmp->pm_HugeSectors - pmp->pm_firstcluster) / 205 SecPerClust) + 1; 206 pmp->pm_fatsize = pmp->pm_FATsecs * pmp->pm_BytesPerSec; 207 208 if (pmp->pm_fatmask == 0) { 209 if (pmp->pm_maxcluster 210 <= ((CLUST_RSRVD - CLUST_FIRST) & FAT12_MASK)) { 211 /* 212 * This will usually be a floppy disk. This size makes 213 * sure that one FAT entry will not be split across 214 * multiple blocks. 215 */ 216 pmp->pm_fatmask = FAT12_MASK; 217 pmp->pm_fatmult = 3; 218 pmp->pm_fatdiv = 2; 219 } else { 220 pmp->pm_fatmask = FAT16_MASK; 221 pmp->pm_fatmult = 2; 222 pmp->pm_fatdiv = 1; 223 } 224 } 225 if (FAT12(pmp)) 226 pmp->pm_fatblocksize = 3 * pmp->pm_BytesPerSec; 227 else 228 pmp->pm_fatblocksize = MAXBSIZE; 229 230 pmp->pm_fatblocksec = pmp->pm_fatblocksize / pmp->pm_BytesPerSec; 231 pmp->pm_bnshift = ffs(pmp->pm_BytesPerSec) - 1; 232 233 /* 234 * Compute mask and shift value for isolating cluster relative byte 235 * offsets and cluster numbers from a file offset. 236 */ 237 pmp->pm_bpcluster = SecPerClust * pmp->pm_BytesPerSec; 238 pmp->pm_crbomask = pmp->pm_bpcluster - 1; 239 pmp->pm_cnshift = ffs(pmp->pm_bpcluster) - 1; 240 241 MSDOSFS_DPRINTF(("%s(fatmask=%lu, fatmult=%u, fatdiv=%u, " 242 "fatblocksize=%lu, fatblocksec=%lu, bnshift=%lu, pbcluster=%lu, " 243 "crbomask=%lu, cnshift=%lu)\n", 244 __func__, (unsigned long)pmp->pm_fatmask, pmp->pm_fatmult, 245 pmp->pm_fatdiv, pmp->pm_fatblocksize, pmp->pm_fatblocksec, 246 pmp->pm_bnshift, pmp->pm_bpcluster, pmp->pm_crbomask, 247 pmp->pm_cnshift)); 248 /* 249 * Check for valid cluster size 250 * must be a power of 2 251 */ 252 if (pmp->pm_bpcluster ^ (1 << pmp->pm_cnshift)) { 253 MSDOSFS_DPRINTF(("bpcluster %lu cnshift %lu\n", 254 pmp->pm_bpcluster, pmp->pm_cnshift)); 255 error = EINVAL; 256 goto error_exit; 257 } 258 259 /* 260 * Release the bootsector buffer. 261 */ 262 brelse(bp); 263 bp = NULL; 264 265 /* 266 * Check FSInfo. 267 */ 268 if (pmp->pm_fsinfo) { 269 struct fsinfo *fp; 270 271 /* 272 * XXX If the fsinfo block is stored on media with 273 * 2KB or larger sectors, is the fsinfo structure 274 * padded at the end or in the middle? 275 */ 276 if ((error = bread(devvp, pmp->pm_fsinfo, pmp->pm_BytesPerSec, 277 0, &bp)) != 0) 278 goto error_exit; 279 fp = (struct fsinfo *)bp->b_data; 280 if (!memcmp(fp->fsisig1, "RRaA", 4) 281 && !memcmp(fp->fsisig2, "rrAa", 4) 282 && !memcmp(fp->fsisig3, "\0\0\125\252", 4)) 283 pmp->pm_nxtfree = getulong(fp->fsinxtfree); 284 else 285 pmp->pm_fsinfo = 0; 286 brelse(bp); 287 bp = NULL; 288 } 289 290 /* 291 * Check and validate (or perhaps invalidate?) the fsinfo structure? 292 * XXX 293 */ 294 if (pmp->pm_fsinfo) { 295 if ((pmp->pm_nxtfree == 0xffffffffUL) || 296 (pmp->pm_nxtfree > pmp->pm_maxcluster)) 297 pmp->pm_fsinfo = 0; 298 } 299 300 /* 301 * Allocate memory for the bitmap of allocated clusters, and then 302 * fill it in. 303 */ 304 pmp->pm_inusemap = ecalloc(sizeof(*pmp->pm_inusemap), 305 ((pmp->pm_maxcluster + N_INUSEBITS) / N_INUSEBITS)); 306 /* 307 * fillinusemap() needs pm_devvp. 308 */ 309 pmp->pm_dev = 0; 310 pmp->pm_devvp = devvp; 311 312 /* 313 * Have the inuse map filled in. 314 */ 315 if ((error = fillinusemap(pmp)) != 0) { 316 MSDOSFS_DPRINTF(("fillinusemap %d\n", error)); 317 goto error_exit; 318 } 319 320 /* 321 * Finish up. 322 */ 323 if (ronly) 324 pmp->pm_flags |= MSDOSFSMNT_RONLY; 325 else 326 pmp->pm_fmod = 1; 327 328 /* 329 * If we ever do quotas for DOS filesystems this would be a place 330 * to fill in the info in the msdosfsmount structure. You dolt, 331 * quotas on dos filesystems make no sense because files have no 332 * owners on dos filesystems. of course there is some empty space 333 * in the directory entry where we could put uid's and gid's. 334 */ 335 336 return pmp; 337 338 error_exit: 339 if (bp) 340 brelse(bp); 341 if (pmp) { 342 if (pmp->pm_inusemap) 343 free(pmp->pm_inusemap); 344 free(pmp); 345 } 346 errno = error; 347 return NULL; 348 } 349 350 int 351 msdosfs_root(struct msdosfsmount *pmp, struct vnode *vp) { 352 struct denode *ndep; 353 int error; 354 355 *vp = *pmp->pm_devvp; 356 if ((error = deget(pmp, MSDOSFSROOT, MSDOSFSROOT_OFS, &ndep)) != 0) { 357 errno = error; 358 return -1; 359 } 360 vp->v_data = ndep; 361 return 0; 362 } 363 364 /* 365 * If we have an FSInfo block, update it. 366 */ 367 int 368 msdosfs_fsiflush(struct msdosfsmount *pmp) 369 { 370 struct fsinfo *fp; 371 struct buf *bp; 372 int error; 373 374 if (pmp->pm_fsinfo == 0 || (pmp->pm_flags & MSDOSFS_FSIMOD) == 0) { 375 error = 0; 376 goto out; 377 } 378 error = bread(pmp->pm_devvp, pmp->pm_fsinfo, pmp->pm_BytesPerSec, 379 NOCRED, &bp); 380 if (error != 0) { 381 brelse(bp); 382 goto out; 383 } 384 fp = (struct fsinfo *)bp->b_data; 385 putulong(fp->fsinfree, pmp->pm_freeclustercount); 386 putulong(fp->fsinxtfree, pmp->pm_nxtfree); 387 pmp->pm_flags &= ~MSDOSFS_FSIMOD; 388 error = bwrite(bp); 389 390 out: 391 return (error); 392 } 393