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 <fs/msdosfs/bootsect.h> 65 #include <fs/msdosfs/bpb.h> 66 #include "msdos/denode.h" 67 #include <fs/msdosfs/fat.h> 68 #include <fs/msdosfs/msdosfsmount.h> 69 70 #include <mkfs_msdos.h> 71 72 #include "makefs.h" 73 #include "msdos.h" 74 75 struct msdosfsmount * 76 m_msdosfs_mount(struct m_vnode *devvp) 77 { 78 struct msdosfsmount *pmp = NULL; 79 struct m_buf *bp; 80 union bootsector *bsp; 81 struct byte_bpb33 *b33; 82 struct byte_bpb50 *b50; 83 struct byte_bpb710 *b710; 84 uint8_t SecPerClust; 85 int ronly = 0, error; 86 unsigned secsize = 512; 87 88 MSDOSFS_DPRINTF(("%s(bread 0)\n", __func__)); 89 if ((error = bread((void *)devvp, 0, secsize, 0, &bp)) != 0) 90 goto error_exit; 91 92 bsp = (union bootsector *)bp->b_data; 93 b33 = (struct byte_bpb33 *)bsp->bs33.bsBPB; 94 b50 = (struct byte_bpb50 *)bsp->bs50.bsBPB; 95 b710 = (struct byte_bpb710 *)bsp->bs710.bsBPB; 96 97 if (bsp->bs50.bsBootSectSig0 != BOOTSIG0 || 98 bsp->bs50.bsBootSectSig1 != BOOTSIG1) { 99 MSDOSFS_DPRINTF(("bootsig0 %d bootsig1 %d\n", 100 bsp->bs50.bsBootSectSig0, 101 bsp->bs50.bsBootSectSig1)); 102 error = EINVAL; 103 goto error_exit; 104 } 105 106 pmp = ecalloc(1, sizeof(*pmp)); 107 /* 108 * Compute several useful quantities from the bpb in the 109 * bootsector. Copy in the dos 5 variant of the bpb then fix up 110 * the fields that are different between dos 5 and dos 3.3. 111 */ 112 SecPerClust = b50->bpbSecPerClust; 113 pmp->pm_BytesPerSec = getushort(b50->bpbBytesPerSec); 114 pmp->pm_ResSectors = getushort(b50->bpbResSectors); 115 pmp->pm_FATs = b50->bpbFATs; 116 pmp->pm_RootDirEnts = getushort(b50->bpbRootDirEnts); 117 pmp->pm_Sectors = getushort(b50->bpbSectors); 118 pmp->pm_FATsecs = getushort(b50->bpbFATsecs); 119 pmp->pm_SecPerTrack = getushort(b50->bpbSecPerTrack); 120 pmp->pm_Heads = getushort(b50->bpbHeads); 121 pmp->pm_Media = b50->bpbMedia; 122 123 MSDOSFS_DPRINTF(("%s(BytesPerSec=%u, ResSectors=%u, FATs=%d, " 124 "RootDirEnts=%u, Sectors=%u, FATsecs=%lu, SecPerTrack=%u, " 125 "Heads=%u, Media=%u)\n", 126 __func__, pmp->pm_BytesPerSec, pmp->pm_ResSectors, 127 pmp->pm_FATs, pmp->pm_RootDirEnts, pmp->pm_Sectors, 128 pmp->pm_FATsecs, pmp->pm_SecPerTrack, pmp->pm_Heads, 129 pmp->pm_Media)); 130 131 /* XXX - We should probably check more values here */ 132 if (!pmp->pm_BytesPerSec || !SecPerClust 133 || pmp->pm_SecPerTrack > 63) { 134 MSDOSFS_DPRINTF(("bytespersec %d secperclust %d " 135 "secpertrack %d\n", pmp->pm_BytesPerSec, 136 SecPerClust, pmp->pm_SecPerTrack)); 137 error = EINVAL; 138 goto error_exit; 139 } 140 141 if (pmp->pm_Sectors == 0) { 142 pmp->pm_HiddenSects = getulong(b50->bpbHiddenSecs); 143 pmp->pm_HugeSectors = getulong(b50->bpbHugeSectors); 144 } else { 145 pmp->pm_HiddenSects = getushort(b33->bpbHiddenSecs); 146 pmp->pm_HugeSectors = pmp->pm_Sectors; 147 } 148 149 pmp->pm_flags = 0; 150 if (pmp->pm_RootDirEnts == 0) { 151 unsigned short vers = getushort(b710->bpbFSVers); 152 /* 153 * Some say that bsBootSectSig[23] must be zero, but 154 * Windows does not require this and some digital cameras 155 * do not set these to zero. Therefore, do not insist. 156 */ 157 if (pmp->pm_Sectors || pmp->pm_FATsecs || vers) { 158 MSDOSFS_DPRINTF(("sectors %d fatsecs %lu vers %d\n", 159 pmp->pm_Sectors, pmp->pm_FATsecs, vers)); 160 error = EINVAL; 161 goto error_exit; 162 } 163 pmp->pm_fatmask = FAT32_MASK; 164 pmp->pm_fatmult = 4; 165 pmp->pm_fatdiv = 1; 166 pmp->pm_FATsecs = getulong(b710->bpbBigFATsecs); 167 168 /* mirrorring is enabled if the FATMIRROR bit is not set */ 169 if ((getushort(b710->bpbExtFlags) & FATMIRROR) == 0) 170 pmp->pm_flags |= MSDOSFS_FATMIRROR; 171 else 172 pmp->pm_curfat = getushort(b710->bpbExtFlags) & FATNUM; 173 } else 174 pmp->pm_flags |= MSDOSFS_FATMIRROR; 175 176 /* Check that fs has nonzero FAT size */ 177 if (pmp->pm_FATsecs == 0) { 178 MSDOSFS_DPRINTF(("FATsecs is 0\n")); 179 error = EINVAL; 180 goto error_exit; 181 } 182 183 pmp->pm_fatblk = pmp->pm_ResSectors; 184 if (FAT32(pmp)) { 185 pmp->pm_rootdirblk = getulong(b710->bpbRootClust); 186 pmp->pm_firstcluster = pmp->pm_fatblk 187 + (pmp->pm_FATs * pmp->pm_FATsecs); 188 pmp->pm_fsinfo = getushort(b710->bpbFSInfo); 189 } else { 190 pmp->pm_rootdirblk = pmp->pm_fatblk + 191 (pmp->pm_FATs * pmp->pm_FATsecs); 192 pmp->pm_rootdirsize = (pmp->pm_RootDirEnts * sizeof(struct direntry) 193 + pmp->pm_BytesPerSec - 1) 194 / pmp->pm_BytesPerSec;/* in sectors */ 195 pmp->pm_firstcluster = pmp->pm_rootdirblk + pmp->pm_rootdirsize; 196 } 197 198 pmp->pm_maxcluster = ((pmp->pm_HugeSectors - pmp->pm_firstcluster) / 199 SecPerClust) + 1; 200 pmp->pm_fatsize = pmp->pm_FATsecs * pmp->pm_BytesPerSec; 201 202 if (pmp->pm_fatmask == 0) { 203 if (pmp->pm_maxcluster 204 <= ((CLUST_RSRVD - CLUST_FIRST) & FAT12_MASK)) { 205 /* 206 * This will usually be a floppy disk. This size makes 207 * sure that one FAT entry will not be split across 208 * multiple blocks. 209 */ 210 pmp->pm_fatmask = FAT12_MASK; 211 pmp->pm_fatmult = 3; 212 pmp->pm_fatdiv = 2; 213 } else { 214 pmp->pm_fatmask = FAT16_MASK; 215 pmp->pm_fatmult = 2; 216 pmp->pm_fatdiv = 1; 217 } 218 } 219 if (FAT12(pmp)) 220 pmp->pm_fatblocksize = 3 * pmp->pm_BytesPerSec; 221 else 222 pmp->pm_fatblocksize = MAXBSIZE; 223 224 pmp->pm_fatblocksec = pmp->pm_fatblocksize / pmp->pm_BytesPerSec; 225 pmp->pm_bnshift = ffs(pmp->pm_BytesPerSec) - 1; 226 227 /* 228 * Compute mask and shift value for isolating cluster relative byte 229 * offsets and cluster numbers from a file offset. 230 */ 231 pmp->pm_bpcluster = SecPerClust * pmp->pm_BytesPerSec; 232 pmp->pm_crbomask = pmp->pm_bpcluster - 1; 233 pmp->pm_cnshift = ffs(pmp->pm_bpcluster) - 1; 234 235 MSDOSFS_DPRINTF(("%s(fatmask=%lu, fatmult=%u, fatdiv=%u, " 236 "fatblocksize=%lu, fatblocksec=%lu, bnshift=%lu, pbcluster=%lu, " 237 "crbomask=%lu, cnshift=%lu)\n", 238 __func__, (unsigned long)pmp->pm_fatmask, pmp->pm_fatmult, 239 pmp->pm_fatdiv, pmp->pm_fatblocksize, pmp->pm_fatblocksec, 240 pmp->pm_bnshift, pmp->pm_bpcluster, pmp->pm_crbomask, 241 pmp->pm_cnshift)); 242 /* 243 * Check for valid cluster size 244 * must be a power of 2 245 */ 246 if (pmp->pm_bpcluster ^ (1 << pmp->pm_cnshift)) { 247 MSDOSFS_DPRINTF(("bpcluster %lu cnshift %lu\n", 248 pmp->pm_bpcluster, pmp->pm_cnshift)); 249 error = EINVAL; 250 goto error_exit; 251 } 252 253 /* 254 * Release the bootsector buffer. 255 */ 256 brelse(bp); 257 bp = NULL; 258 259 /* 260 * Check FSInfo. 261 */ 262 if (pmp->pm_fsinfo) { 263 struct fsinfo *fp; 264 265 /* 266 * XXX If the fsinfo block is stored on media with 267 * 2KB or larger sectors, is the fsinfo structure 268 * padded at the end or in the middle? 269 */ 270 if ((error = bread((void *)devvp, pmp->pm_fsinfo, 271 pmp->pm_BytesPerSec, 0, &bp)) != 0) 272 goto error_exit; 273 fp = (struct fsinfo *)bp->b_data; 274 if (!memcmp(fp->fsisig1, "RRaA", 4) 275 && !memcmp(fp->fsisig2, "rrAa", 4) 276 && !memcmp(fp->fsisig3, "\0\0\125\252", 4)) 277 pmp->pm_nxtfree = getulong(fp->fsinxtfree); 278 else 279 pmp->pm_fsinfo = 0; 280 brelse(bp); 281 bp = NULL; 282 } 283 284 /* 285 * Check and validate (or perhaps invalidate?) the fsinfo structure? 286 * XXX 287 */ 288 if (pmp->pm_fsinfo) { 289 if ((pmp->pm_nxtfree == 0xffffffffUL) || 290 (pmp->pm_nxtfree > pmp->pm_maxcluster)) 291 pmp->pm_fsinfo = 0; 292 } 293 294 /* 295 * Allocate memory for the bitmap of allocated clusters, and then 296 * fill it in. 297 */ 298 pmp->pm_inusemap = ecalloc(sizeof(*pmp->pm_inusemap), 299 ((pmp->pm_maxcluster + N_INUSEBITS) / N_INUSEBITS)); 300 /* 301 * fillinusemap() needs pm_devvp. 302 */ 303 pmp->pm_dev = 0; 304 pmp->pm_devvp = (void *)devvp; 305 306 /* 307 * Have the inuse map filled in. 308 */ 309 if ((error = fillinusemap(pmp)) != 0) { 310 MSDOSFS_DPRINTF(("fillinusemap %d\n", error)); 311 goto error_exit; 312 } 313 314 /* 315 * Finish up. 316 */ 317 if (ronly) 318 pmp->pm_flags |= MSDOSFSMNT_RONLY; 319 else 320 pmp->pm_fmod = 1; 321 322 /* 323 * If we ever do quotas for DOS filesystems this would be a place 324 * to fill in the info in the msdosfsmount structure. You dolt, 325 * quotas on dos filesystems make no sense because files have no 326 * owners on dos filesystems. of course there is some empty space 327 * in the directory entry where we could put uid's and gid's. 328 */ 329 330 return pmp; 331 332 error_exit: 333 if (bp) 334 brelse(bp); 335 if (pmp) { 336 if (pmp->pm_inusemap) 337 free(pmp->pm_inusemap); 338 free(pmp); 339 } 340 errno = error; 341 return NULL; 342 } 343 344 int 345 msdosfs_root(struct msdosfsmount *pmp, struct m_vnode *vp) { 346 struct denode *ndep; 347 int error; 348 349 *vp = *(struct m_vnode *)pmp->pm_devvp; 350 if ((error = deget(pmp, MSDOSFSROOT, MSDOSFSROOT_OFS, 0, &ndep)) != 0) { 351 errno = error; 352 return -1; 353 } 354 vp->v_data = ndep; 355 return 0; 356 } 357 358 /* 359 * If we have an FSInfo block, update it. 360 */ 361 int 362 msdosfs_fsiflush(struct msdosfsmount *pmp) 363 { 364 struct fsinfo *fp; 365 struct m_buf *bp; 366 int error; 367 368 if (pmp->pm_fsinfo == 0 || (pmp->pm_flags & MSDOSFS_FSIMOD) == 0) { 369 error = 0; 370 goto out; 371 } 372 error = bread((void *)pmp->pm_devvp, pmp->pm_fsinfo, 373 pmp->pm_BytesPerSec, NOCRED, &bp); 374 if (error != 0) { 375 brelse(bp); 376 goto out; 377 } 378 fp = (struct fsinfo *)bp->b_data; 379 putulong(fp->fsinfree, pmp->pm_freeclustercount); 380 putulong(fp->fsinxtfree, pmp->pm_nxtfree); 381 pmp->pm_flags &= ~MSDOSFS_FSIMOD; 382 error = bwrite(bp); 383 384 out: 385 return (error); 386 } 387