1 /* $OpenBSD: msdosfs_vfsops.c,v 1.13 2021/10/06 00:40:41 deraadt Exp $ */ 2 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 51 #include <sys/param.h> /* MAXBSIZE */ 52 #include <sys/types.h> 53 54 #include "ffs/buf.h" 55 56 #include <msdosfs/bpb.h> 57 #include <msdosfs/bootsect.h> 58 #include "msdos/direntry.h" 59 #include "msdos/denode.h" 60 #include "msdos/msdosfsmount.h" 61 #include "msdos/fat.h" 62 63 #include <stdio.h> 64 #include <errno.h> 65 #include <stdlib.h> 66 #include <string.h> 67 #include <util.h> 68 69 #include "makefs.h" 70 #include "msdos.h" 71 #include "msdos/mkfs_msdos.h" 72 73 #ifdef MSDOSFS_DEBUG 74 #define DPRINTF(a) printf a 75 #else 76 #define DPRINTF(a) 77 #endif 78 79 struct msdosfsmount * 80 msdosfs_mount(struct mkfsvnode *devvp, int flags) 81 { 82 struct msdosfsmount *pmp = NULL; 83 struct mkfsbuf *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 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 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 pmp->pm_minuteswest = 0; 129 130 DPRINTF(("%s(BytesPerSec=%u, ResSectors=%u, FATs=%d, RootDirEnts=%u, " 131 "Sectors=%u, FATsecs=%lu, SecPerTrack=%u, Heads=%u, Media=%u)\n", 132 __func__, pmp->pm_BytesPerSec, pmp->pm_ResSectors, pmp->pm_FATs, 133 pmp->pm_RootDirEnts, pmp->pm_Sectors, pmp->pm_FATsecs, 134 pmp->pm_SecPerTrack, pmp->pm_Heads, pmp->pm_Media)); 135 /* XXX - We should probably check more values here */ 136 if (!pmp->pm_BytesPerSec || !SecPerClust 137 || pmp->pm_SecPerTrack > 63) { 138 DPRINTF(("bytespersec %d secperclust %d " 139 "secpertrack %d\n", 140 pmp->pm_BytesPerSec, SecPerClust, 141 pmp->pm_SecPerTrack)); 142 error = EINVAL; 143 goto error_exit; 144 } 145 146 pmp->pm_flags = flags & MSDOSFSMNT_MNTOPT; 147 if (pmp->pm_flags & MSDOSFSMNT_NOWIN95) 148 pmp->pm_flags |= MSDOSFSMNT_SHORTNAME; 149 150 if (pmp->pm_Sectors == 0) { 151 pmp->pm_HiddenSects = getulong(b50->bpbHiddenSecs); 152 pmp->pm_HugeSectors = getulong(b50->bpbHugeSectors); 153 } else { 154 pmp->pm_HiddenSects = getushort(b33->bpbHiddenSecs); 155 pmp->pm_HugeSectors = pmp->pm_Sectors; 156 } 157 158 if (pmp->pm_RootDirEnts == 0) { 159 unsigned short vers = getushort(b710->bpbFSVers); 160 /* 161 * Some say that bsBootSectSig[23] must be zero, but 162 * Windows does not require this and some digital cameras 163 * do not set these to zero. Therefore, do not insist. 164 */ 165 if (pmp->pm_Sectors || pmp->pm_FATsecs || vers) { 166 DPRINTF(("sectors %d fatsecs %lu vers %d\n", 167 pmp->pm_Sectors, pmp->pm_FATsecs, vers)); 168 error = EINVAL; 169 goto error_exit; 170 } 171 pmp->pm_fatmask = FAT32_MASK; 172 pmp->pm_fatmult = 4; 173 pmp->pm_fatdiv = 1; 174 pmp->pm_FATsecs = getulong(b710->bpbBigFATsecs); 175 176 /* mirrorring is enabled if the FATMIRROR bit is not set */ 177 if ((getushort(b710->bpbExtFlags) & FATMIRROR) == 0) 178 pmp->pm_flags |= MSDOSFS_FATMIRROR; 179 else 180 pmp->pm_curfat = getushort(b710->bpbExtFlags) & FATNUM; 181 } else 182 pmp->pm_flags |= MSDOSFS_FATMIRROR; 183 184 /* Check that fs has nonzero FAT size */ 185 if (pmp->pm_FATsecs == 0) { 186 DPRINTF(("FATsecs is 0\n")); 187 error = EINVAL; 188 goto error_exit; 189 } 190 191 pmp->pm_fatblk = pmp->pm_ResSectors; 192 if (FAT32(pmp)) { 193 pmp->pm_rootdirblk = getulong(b710->bpbRootClust); 194 pmp->pm_firstcluster = pmp->pm_fatblk 195 + (pmp->pm_FATs * pmp->pm_FATsecs); 196 pmp->pm_fsinfo = getushort(b710->bpbFSInfo); 197 } else { 198 pmp->pm_rootdirblk = pmp->pm_fatblk + 199 (pmp->pm_FATs * pmp->pm_FATsecs); 200 pmp->pm_rootdirsize = (pmp->pm_RootDirEnts * sizeof(struct direntry) 201 + pmp->pm_BytesPerSec - 1) 202 / pmp->pm_BytesPerSec;/* in sectors */ 203 pmp->pm_firstcluster = pmp->pm_rootdirblk + pmp->pm_rootdirsize; 204 } 205 206 pmp->pm_nmbrofclusters = (pmp->pm_HugeSectors - pmp->pm_firstcluster) / 207 SecPerClust; 208 pmp->pm_maxcluster = pmp->pm_nmbrofclusters + 1; 209 pmp->pm_fatsize = pmp->pm_FATsecs * pmp->pm_BytesPerSec; 210 211 if (pmp->pm_fatmask == 0) { 212 if (pmp->pm_maxcluster 213 <= ((CLUST_RSRVD - CLUST_FIRST) & FAT12_MASK)) { 214 /* 215 * This will usually be a floppy disk. This size makes 216 * sure that one FAT entry will not be split across 217 * multiple blocks. 218 */ 219 pmp->pm_fatmask = FAT12_MASK; 220 pmp->pm_fatmult = 3; 221 pmp->pm_fatdiv = 2; 222 } else { 223 pmp->pm_fatmask = FAT16_MASK; 224 pmp->pm_fatmult = 2; 225 pmp->pm_fatdiv = 1; 226 } 227 } 228 if (FAT12(pmp)) 229 pmp->pm_fatblocksize = 3 * pmp->pm_BytesPerSec; 230 else 231 pmp->pm_fatblocksize = MAXBSIZE; 232 233 pmp->pm_fatblocksec = pmp->pm_fatblocksize / pmp->pm_BytesPerSec; 234 pmp->pm_bnshift = ffs(pmp->pm_BytesPerSec) - 1; 235 236 /* 237 * Compute mask and shift value for isolating cluster relative byte 238 * offsets and cluster numbers from a file offset. 239 */ 240 pmp->pm_bpcluster = SecPerClust * pmp->pm_BytesPerSec; 241 pmp->pm_crbomask = pmp->pm_bpcluster - 1; 242 pmp->pm_cnshift = ffs(pmp->pm_bpcluster) - 1; 243 244 DPRINTF(("%s(fatmask=%lu, fatmult=%u, fatdiv=%u, fatblocksize=%lu, " 245 "fatblocksec=%lu, bnshift=%lu, pbcluster=%lu, crbomask=%lu, " 246 "cnshift=%lu)\n", 247 __func__, pmp->pm_fatmask, pmp->pm_fatmult, pmp->pm_fatdiv, 248 pmp->pm_fatblocksize, pmp->pm_fatblocksec, pmp->pm_bnshift, 249 pmp->pm_bpcluster, pmp->pm_crbomask, pmp->pm_cnshift)); 250 /* 251 * Check for valid cluster size 252 * must be a power of 2 253 */ 254 if (pmp->pm_bpcluster ^ (1 << pmp->pm_cnshift)) { 255 DPRINTF(("bpcluster %lu cnshift %lu\n", 256 pmp->pm_bpcluster, pmp->pm_cnshift)); 257 error = EINVAL; 258 goto error_exit; 259 } 260 261 /* 262 * Release the bootsector buffer. 263 */ 264 brelse(bp, BC_AGE); 265 bp = NULL; 266 267 /* 268 * Check FSInfo. 269 */ 270 if (pmp->pm_fsinfo) { 271 struct fsinfo *fp; 272 273 /* 274 * XXX If the fsinfo block is stored on media with 275 * 2KB or larger sectors, is the fsinfo structure 276 * padded at the end or in the middle? 277 */ 278 DPRINTF(("%s(bread %lu)\n", __func__, 279 (unsigned long)de_bn2kb(pmp, pmp->pm_fsinfo))); 280 if ((error = bread(devvp, de_bn2kb(pmp, pmp->pm_fsinfo), 281 pmp->pm_BytesPerSec, 0, &bp)) != 0) 282 goto error_exit; 283 fp = (struct fsinfo *)bp->b_data; 284 if (!memcmp(fp->fsisig1, "RRaA", 4) 285 && !memcmp(fp->fsisig2, "rrAa", 4) 286 && !memcmp(fp->fsisig3, "\0\0\125\252", 4) 287 && !memcmp(fp->fsisig4, "\0\0\125\252", 4)) 288 pmp->pm_nxtfree = getulong(fp->fsinxtfree); 289 else 290 pmp->pm_fsinfo = 0; 291 brelse(bp, 0); 292 bp = NULL; 293 } 294 295 /* 296 * Check and validate (or perhaps invalidate?) the fsinfo structure? 297 * XXX 298 */ 299 if (pmp->pm_fsinfo) { 300 if ((pmp->pm_nxtfree == 0xffffffffUL) || 301 (pmp->pm_nxtfree > pmp->pm_maxcluster)) 302 pmp->pm_fsinfo = 0; 303 } 304 305 /* 306 * Allocate memory for the bitmap of allocated clusters, and then 307 * fill it in. 308 */ 309 pmp->pm_inusemap = ecalloc(sizeof(*pmp->pm_inusemap), 310 ((pmp->pm_maxcluster + N_INUSEBITS) / N_INUSEBITS)); 311 /* 312 * fillinusemap() needs pm_devvp. 313 */ 314 pmp->pm_dev = 0; 315 pmp->pm_devvp = devvp; 316 317 /* 318 * Have the inuse map filled in. 319 */ 320 if ((error = fillinusemap(pmp)) != 0) { 321 DPRINTF(("fillinusemap %d\n", error)); 322 goto error_exit; 323 } 324 325 /* 326 * Finish up. 327 */ 328 if (ronly) 329 pmp->pm_flags |= MSDOSFSMNT_RONLY; 330 else 331 pmp->pm_fmod = 1; 332 333 return pmp; 334 335 error_exit: 336 if (bp) 337 brelse(bp, BC_AGE); 338 if (pmp) { 339 if (pmp->pm_inusemap) 340 free(pmp->pm_inusemap); 341 free(pmp); 342 } 343 errno = error; 344 return NULL; 345 } 346 347 int 348 msdosfs_root(struct msdosfsmount *pmp, struct mkfsvnode *vp) { 349 struct denode *ndep; 350 int error; 351 352 *vp = *pmp->pm_devvp; 353 if ((error = deget(pmp, MSDOSFSROOT, MSDOSFSROOT_OFS, &ndep)) != 0) { 354 errno = error; 355 return -1; 356 } 357 vp->v_data = ndep; 358 return 0; 359 } 360