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 #include <sys/param.h> 53 #include <sys/mount.h> 54 55 #include <errno.h> 56 #include <stdbool.h> 57 #include <stdio.h> 58 #include <string.h> 59 #include <stdlib.h> 60 #include <util.h> 61 62 #include <fs/msdosfs/bootsect.h> 63 #include <fs/msdosfs/bpb.h> 64 #include "msdos/denode.h" 65 #include <fs/msdosfs/fat.h> 66 #include <fs/msdosfs/msdosfsmount.h> 67 68 #include <mkfs_msdos.h> 69 70 #include "makefs.h" 71 #include "msdos.h" 72 73 struct msdosfsmount * 74 m_msdosfs_mount(struct m_vnode *devvp) 75 { 76 struct msdosfsmount *pmp = NULL; 77 struct m_buf *bp; 78 union bootsector *bsp; 79 struct byte_bpb33 *b33; 80 struct byte_bpb50 *b50; 81 struct byte_bpb710 *b710; 82 uint8_t SecPerClust; 83 int ronly = 0, error; 84 unsigned secsize = 512; 85 86 MSDOSFS_DPRINTF(("%s(bread 0)\n", __func__)); 87 if ((error = bread((void *)devvp, 0, secsize, 0, &bp)) != 0) 88 goto error_exit; 89 90 bsp = (union bootsector *)bp->b_data; 91 b33 = (struct byte_bpb33 *)bsp->bs33.bsBPB; 92 b50 = (struct byte_bpb50 *)bsp->bs50.bsBPB; 93 b710 = (struct byte_bpb710 *)bsp->bs710.bsBPB; 94 95 if (bsp->bs50.bsBootSectSig0 != BOOTSIG0 || 96 bsp->bs50.bsBootSectSig1 != BOOTSIG1) { 97 MSDOSFS_DPRINTF(("bootsig0 %d bootsig1 %d\n", 98 bsp->bs50.bsBootSectSig0, 99 bsp->bs50.bsBootSectSig1)); 100 error = EINVAL; 101 goto error_exit; 102 } 103 104 pmp = ecalloc(1, sizeof(*pmp)); 105 /* 106 * Compute several useful quantities from the bpb in the 107 * bootsector. Copy in the dos 5 variant of the bpb then fix up 108 * the fields that are different between dos 5 and dos 3.3. 109 */ 110 SecPerClust = b50->bpbSecPerClust; 111 pmp->pm_BytesPerSec = getushort(b50->bpbBytesPerSec); 112 pmp->pm_ResSectors = getushort(b50->bpbResSectors); 113 pmp->pm_FATs = b50->bpbFATs; 114 pmp->pm_RootDirEnts = getushort(b50->bpbRootDirEnts); 115 pmp->pm_Sectors = getushort(b50->bpbSectors); 116 pmp->pm_FATsecs = getushort(b50->bpbFATsecs); 117 pmp->pm_SecPerTrack = getushort(b50->bpbSecPerTrack); 118 pmp->pm_Heads = getushort(b50->bpbHeads); 119 pmp->pm_Media = b50->bpbMedia; 120 121 MSDOSFS_DPRINTF(("%s(BytesPerSec=%u, ResSectors=%u, FATs=%d, " 122 "RootDirEnts=%u, Sectors=%u, FATsecs=%lu, SecPerTrack=%u, " 123 "Heads=%u, Media=%u)\n", 124 __func__, pmp->pm_BytesPerSec, pmp->pm_ResSectors, 125 pmp->pm_FATs, pmp->pm_RootDirEnts, pmp->pm_Sectors, 126 pmp->pm_FATsecs, pmp->pm_SecPerTrack, pmp->pm_Heads, 127 pmp->pm_Media)); 128 129 /* XXX - We should probably check more values here */ 130 if (!pmp->pm_BytesPerSec || !SecPerClust 131 || pmp->pm_SecPerTrack > 63) { 132 MSDOSFS_DPRINTF(("bytespersec %d secperclust %d " 133 "secpertrack %d\n", pmp->pm_BytesPerSec, 134 SecPerClust, pmp->pm_SecPerTrack)); 135 error = EINVAL; 136 goto error_exit; 137 } 138 139 if (pmp->pm_Sectors == 0) { 140 pmp->pm_HiddenSects = getulong(b50->bpbHiddenSecs); 141 pmp->pm_HugeSectors = getulong(b50->bpbHugeSectors); 142 } else { 143 pmp->pm_HiddenSects = getushort(b33->bpbHiddenSecs); 144 pmp->pm_HugeSectors = pmp->pm_Sectors; 145 } 146 147 pmp->pm_flags = 0; 148 if (pmp->pm_RootDirEnts == 0) { 149 unsigned short vers = getushort(b710->bpbFSVers); 150 /* 151 * Some say that bsBootSectSig[23] must be zero, but 152 * Windows does not require this and some digital cameras 153 * do not set these to zero. Therefore, do not insist. 154 */ 155 if (pmp->pm_Sectors || pmp->pm_FATsecs || vers) { 156 MSDOSFS_DPRINTF(("sectors %d fatsecs %lu vers %d\n", 157 pmp->pm_Sectors, pmp->pm_FATsecs, vers)); 158 error = EINVAL; 159 goto error_exit; 160 } 161 pmp->pm_fatmask = FAT32_MASK; 162 pmp->pm_fatmult = 4; 163 pmp->pm_fatdiv = 1; 164 pmp->pm_FATsecs = getulong(b710->bpbBigFATsecs); 165 166 /* mirrorring is enabled if the FATMIRROR bit is not set */ 167 if ((getushort(b710->bpbExtFlags) & FATMIRROR) == 0) 168 pmp->pm_flags |= MSDOSFS_FATMIRROR; 169 else 170 pmp->pm_curfat = getushort(b710->bpbExtFlags) & FATNUM; 171 } else 172 pmp->pm_flags |= MSDOSFS_FATMIRROR; 173 174 /* Check that fs has nonzero FAT size */ 175 if (pmp->pm_FATsecs == 0) { 176 MSDOSFS_DPRINTF(("FATsecs is 0\n")); 177 error = EINVAL; 178 goto error_exit; 179 } 180 181 pmp->pm_fatblk = pmp->pm_ResSectors; 182 if (FAT32(pmp)) { 183 pmp->pm_rootdirblk = getulong(b710->bpbRootClust); 184 pmp->pm_firstcluster = pmp->pm_fatblk 185 + (pmp->pm_FATs * pmp->pm_FATsecs); 186 pmp->pm_fsinfo = getushort(b710->bpbFSInfo); 187 } else { 188 pmp->pm_rootdirblk = pmp->pm_fatblk + 189 (pmp->pm_FATs * pmp->pm_FATsecs); 190 pmp->pm_rootdirsize = (pmp->pm_RootDirEnts * sizeof(struct direntry) 191 + pmp->pm_BytesPerSec - 1) 192 / pmp->pm_BytesPerSec;/* in sectors */ 193 pmp->pm_firstcluster = pmp->pm_rootdirblk + pmp->pm_rootdirsize; 194 } 195 196 pmp->pm_maxcluster = ((pmp->pm_HugeSectors - pmp->pm_firstcluster) / 197 SecPerClust) + 1; 198 pmp->pm_fatsize = pmp->pm_FATsecs * pmp->pm_BytesPerSec; 199 200 if (pmp->pm_fatmask == 0) { 201 if (pmp->pm_maxcluster 202 <= ((CLUST_RSRVD - CLUST_FIRST) & FAT12_MASK)) { 203 /* 204 * This will usually be a floppy disk. This size makes 205 * sure that one FAT entry will not be split across 206 * multiple blocks. 207 */ 208 pmp->pm_fatmask = FAT12_MASK; 209 pmp->pm_fatmult = 3; 210 pmp->pm_fatdiv = 2; 211 } else { 212 pmp->pm_fatmask = FAT16_MASK; 213 pmp->pm_fatmult = 2; 214 pmp->pm_fatdiv = 1; 215 } 216 } 217 if (FAT12(pmp)) 218 pmp->pm_fatblocksize = 3 * pmp->pm_BytesPerSec; 219 else 220 pmp->pm_fatblocksize = MAXBSIZE; 221 222 pmp->pm_fatblocksec = pmp->pm_fatblocksize / pmp->pm_BytesPerSec; 223 pmp->pm_bnshift = ffs(pmp->pm_BytesPerSec) - 1; 224 225 /* 226 * Compute mask and shift value for isolating cluster relative byte 227 * offsets and cluster numbers from a file offset. 228 */ 229 pmp->pm_bpcluster = SecPerClust * pmp->pm_BytesPerSec; 230 pmp->pm_crbomask = pmp->pm_bpcluster - 1; 231 pmp->pm_cnshift = ffs(pmp->pm_bpcluster) - 1; 232 233 MSDOSFS_DPRINTF(("%s(fatmask=%lu, fatmult=%u, fatdiv=%u, " 234 "fatblocksize=%lu, fatblocksec=%lu, bnshift=%lu, pbcluster=%lu, " 235 "crbomask=%lu, cnshift=%lu)\n", 236 __func__, (unsigned long)pmp->pm_fatmask, pmp->pm_fatmult, 237 pmp->pm_fatdiv, pmp->pm_fatblocksize, pmp->pm_fatblocksec, 238 pmp->pm_bnshift, pmp->pm_bpcluster, pmp->pm_crbomask, 239 pmp->pm_cnshift)); 240 /* 241 * Check for valid cluster size 242 * must be a power of 2 243 */ 244 if (pmp->pm_bpcluster ^ (1 << pmp->pm_cnshift)) { 245 MSDOSFS_DPRINTF(("bpcluster %lu cnshift %lu\n", 246 pmp->pm_bpcluster, pmp->pm_cnshift)); 247 error = EINVAL; 248 goto error_exit; 249 } 250 251 /* 252 * Release the bootsector buffer. 253 */ 254 brelse(bp); 255 bp = NULL; 256 257 /* 258 * Check FSInfo. 259 */ 260 if (pmp->pm_fsinfo) { 261 struct fsinfo *fp; 262 263 /* 264 * XXX If the fsinfo block is stored on media with 265 * 2KB or larger sectors, is the fsinfo structure 266 * padded at the end or in the middle? 267 */ 268 if ((error = bread((void *)devvp, pmp->pm_fsinfo, 269 pmp->pm_BytesPerSec, 0, &bp)) != 0) 270 goto error_exit; 271 fp = (struct fsinfo *)bp->b_data; 272 if (!memcmp(fp->fsisig1, "RRaA", 4) 273 && !memcmp(fp->fsisig2, "rrAa", 4) 274 && !memcmp(fp->fsisig3, "\0\0\125\252", 4)) 275 pmp->pm_nxtfree = getulong(fp->fsinxtfree); 276 else 277 pmp->pm_fsinfo = 0; 278 brelse(bp); 279 bp = NULL; 280 } 281 282 /* 283 * Check and validate (or perhaps invalidate?) the fsinfo structure? 284 * XXX 285 */ 286 if (pmp->pm_fsinfo) { 287 if ((pmp->pm_nxtfree == 0xffffffffUL) || 288 (pmp->pm_nxtfree > pmp->pm_maxcluster)) 289 pmp->pm_fsinfo = 0; 290 } 291 292 /* 293 * Allocate memory for the bitmap of allocated clusters, and then 294 * fill it in. 295 */ 296 pmp->pm_inusemap = ecalloc(sizeof(*pmp->pm_inusemap), 297 ((pmp->pm_maxcluster + N_INUSEBITS) / N_INUSEBITS)); 298 /* 299 * fillinusemap() needs pm_devvp. 300 */ 301 pmp->pm_dev = 0; 302 pmp->pm_devvp = (void *)devvp; 303 304 /* 305 * Have the inuse map filled in. 306 */ 307 if ((error = fillinusemap(pmp)) != 0) { 308 MSDOSFS_DPRINTF(("fillinusemap %d\n", error)); 309 goto error_exit; 310 } 311 312 /* 313 * Finish up. 314 */ 315 if (ronly) 316 pmp->pm_flags |= MSDOSFSMNT_RONLY; 317 else 318 pmp->pm_fmod = 1; 319 320 /* 321 * If we ever do quotas for DOS filesystems this would be a place 322 * to fill in the info in the msdosfsmount structure. You dolt, 323 * quotas on dos filesystems make no sense because files have no 324 * owners on dos filesystems. of course there is some empty space 325 * in the directory entry where we could put uid's and gid's. 326 */ 327 328 return pmp; 329 330 error_exit: 331 if (bp) 332 brelse(bp); 333 if (pmp) { 334 if (pmp->pm_inusemap) 335 free(pmp->pm_inusemap); 336 free(pmp); 337 } 338 errno = error; 339 return NULL; 340 } 341 342 int 343 msdosfs_root(struct msdosfsmount *pmp, struct m_vnode *vp) { 344 struct denode *ndep; 345 int error; 346 347 *vp = *(struct m_vnode *)pmp->pm_devvp; 348 if ((error = deget(pmp, MSDOSFSROOT, MSDOSFSROOT_OFS, 0, &ndep)) != 0) { 349 errno = error; 350 return -1; 351 } 352 vp->v_data = ndep; 353 return 0; 354 } 355 356 /* 357 * If we have an FSInfo block, update it. 358 */ 359 int 360 msdosfs_fsiflush(struct msdosfsmount *pmp) 361 { 362 struct fsinfo *fp; 363 struct m_buf *bp; 364 int error; 365 366 if (pmp->pm_fsinfo == 0 || (pmp->pm_flags & MSDOSFS_FSIMOD) == 0) { 367 error = 0; 368 goto out; 369 } 370 error = bread((void *)pmp->pm_devvp, pmp->pm_fsinfo, 371 pmp->pm_BytesPerSec, NOCRED, &bp); 372 if (error != 0) { 373 brelse(bp); 374 goto out; 375 } 376 fp = (struct fsinfo *)bp->b_data; 377 putulong(fp->fsinfree, pmp->pm_freeclustercount); 378 putulong(fp->fsinxtfree, pmp->pm_nxtfree); 379 pmp->pm_flags &= ~MSDOSFS_FSIMOD; 380 error = bwrite(bp); 381 382 out: 383 return (error); 384 } 385