1 /* $NetBSD: msdosfs_denode.c,v 1.7 2015/03/29 05:52:59 agc Exp $ */ 2 3 /*- 4 * SPDX-License-Identifier: BSD-4-Clause 5 * 6 * Copyright (C) 1994, 1995, 1997 Wolfgang Solfrank. 7 * Copyright (C) 1994, 1995, 1997 TooLs GmbH. 8 * All rights reserved. 9 * Original code by Paul Popelka (paulp@uts.amdahl.com) (see below). 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in the 18 * documentation and/or other materials provided with the distribution. 19 * 3. All advertising materials mentioning features or use of this software 20 * must display the following acknowledgement: 21 * This product includes software developed by TooLs GmbH. 22 * 4. The name of TooLs GmbH may not be used to endorse or promote products 23 * derived from this software without specific prior written permission. 24 * 25 * THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``AS IS'' AND ANY EXPRESS OR 26 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 27 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 28 * IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 29 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 30 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; 31 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 32 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR 33 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF 34 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 35 */ 36 /*- 37 * Written by Paul Popelka (paulp@uts.amdahl.com) 38 * 39 * You can do anything you want with this software, just don't say you wrote 40 * it, and don't remove this notice. 41 * 42 * This software is provided "as is". 43 * 44 * The author supplies this software to be publicly redistributed on the 45 * understanding that the author is not responsible for the correct 46 * functioning of this software in any circumstances and is not liable for 47 * any damages caused by this software. 48 * 49 * October 1992 50 */ 51 52 #include <sys/cdefs.h> 53 __FBSDID("$FreeBSD$"); 54 55 #include <sys/param.h> 56 #include <sys/errno.h> 57 #include <sys/vnode.h> 58 59 #include <stdbool.h> 60 #include <stdio.h> 61 #include <string.h> 62 #include <stdlib.h> 63 #include <util.h> 64 65 #include "ffs/buf.h" 66 67 #include <fs/msdosfs/bpb.h> 68 #include <fs/msdosfs/direntry.h> 69 #include <fs/msdosfs/denode.h> 70 #include <fs/msdosfs/fat.h> 71 #include <fs/msdosfs/msdosfsmount.h> 72 73 #include "makefs.h" 74 #include "msdos.h" 75 76 77 /* 78 * If deget() succeeds it returns with the gotten denode locked(). 79 * 80 * pmp - address of msdosfsmount structure of the filesystem containing 81 * the denode of interest. The pm_dev field and the address of 82 * the msdosfsmount structure are used. 83 * dirclust - which cluster bp contains, if dirclust is 0 (root directory) 84 * diroffset is relative to the beginning of the root directory, 85 * otherwise it is cluster relative. 86 * diroffset - offset past begin of cluster of denode we want 87 * depp - returns the address of the gotten denode. 88 */ 89 int 90 deget(struct msdosfsmount *pmp, u_long dirclust, u_long diroffset, 91 struct denode **depp) 92 { 93 int error; 94 uint64_t inode; 95 struct direntry *direntptr; 96 struct denode *ldep; 97 struct buf *bp; 98 99 MSDOSFS_DPRINTF(("deget(pmp %p, dirclust %lu, diroffset %lx, depp %p)\n", 100 pmp, dirclust, diroffset, depp)); 101 102 /* 103 * On FAT32 filesystems, root is a (more or less) normal 104 * directory 105 */ 106 if (FAT32(pmp) && dirclust == MSDOSFSROOT) 107 dirclust = pmp->pm_rootdirblk; 108 109 inode = (uint64_t)pmp->pm_bpcluster * dirclust + diroffset; 110 111 ldep = ecalloc(1, sizeof(*ldep)); 112 ldep->de_vnode = NULL; 113 ldep->de_flag = 0; 114 ldep->de_dirclust = dirclust; 115 ldep->de_diroffset = diroffset; 116 ldep->de_inode = inode; 117 ldep->de_pmp = pmp; 118 ldep->de_refcnt = 1; 119 fc_purge(ldep, 0); /* init the FAT cache for this denode */ 120 /* 121 * Copy the directory entry into the denode area of the vnode. 122 */ 123 if ((dirclust == MSDOSFSROOT 124 || (FAT32(pmp) && dirclust == pmp->pm_rootdirblk)) 125 && diroffset == MSDOSFSROOT_OFS) { 126 /* 127 * Directory entry for the root directory. There isn't one, 128 * so we manufacture one. We should probably rummage 129 * through the root directory and find a label entry (if it 130 * exists), and then use the time and date from that entry 131 * as the time and date for the root denode. 132 */ 133 ldep->de_vnode = (struct vnode *)-1; 134 135 ldep->de_Attributes = ATTR_DIRECTORY; 136 ldep->de_LowerCase = 0; 137 if (FAT32(pmp)) 138 ldep->de_StartCluster = pmp->pm_rootdirblk; 139 /* de_FileSize will be filled in further down */ 140 else { 141 ldep->de_StartCluster = MSDOSFSROOT; 142 ldep->de_FileSize = pmp->pm_rootdirsize * DEV_BSIZE; 143 } 144 /* 145 * fill in time and date so that dos2unixtime() doesn't 146 * spit up when called from msdosfs_getattr() with root 147 * denode 148 */ 149 ldep->de_CHun = 0; 150 ldep->de_CTime = 0x0000; /* 00:00:00 */ 151 ldep->de_CDate = (0 << DD_YEAR_SHIFT) | (1 << DD_MONTH_SHIFT) 152 | (1 << DD_DAY_SHIFT); 153 /* Jan 1, 1980 */ 154 ldep->de_ADate = ldep->de_CDate; 155 ldep->de_MTime = ldep->de_CTime; 156 ldep->de_MDate = ldep->de_CDate; 157 /* leave the other fields as garbage */ 158 } else { 159 error = readep(pmp, dirclust, diroffset, &bp, &direntptr); 160 if (error) { 161 ldep->de_Name[0] = SLOT_DELETED; 162 163 *depp = NULL; 164 return (error); 165 } 166 (void)DE_INTERNALIZE(ldep, direntptr); 167 brelse(bp); 168 } 169 170 /* 171 * Fill in a few fields of the vnode and finish filling in the 172 * denode. Then return the address of the found denode. 173 */ 174 if (ldep->de_Attributes & ATTR_DIRECTORY) { 175 /* 176 * Since DOS directory entries that describe directories 177 * have 0 in the filesize field, we take this opportunity 178 * to find out the length of the directory and plug it into 179 * the denode structure. 180 */ 181 u_long size; 182 183 /* 184 * XXX it sometimes happens that the "." entry has cluster 185 * number 0 when it shouldn't. Use the actual cluster number 186 * instead of what is written in directory entry. 187 */ 188 if (diroffset == 0 && ldep->de_StartCluster != dirclust) { 189 MSDOSFS_DPRINTF(("deget(): \".\" entry at clust %lu != %lu\n", 190 dirclust, ldep->de_StartCluster)); 191 192 ldep->de_StartCluster = dirclust; 193 } 194 195 if (ldep->de_StartCluster != MSDOSFSROOT) { 196 error = pcbmap(ldep, 0xffff, 0, &size, 0); 197 if (error == E2BIG) { 198 ldep->de_FileSize = de_cn2off(pmp, size); 199 error = 0; 200 } else { 201 MSDOSFS_DPRINTF(("deget(): pcbmap returned %d\n", 202 error)); 203 } 204 } 205 } 206 *depp = ldep; 207 return (0); 208 } 209 210 /* 211 * Truncate the file described by dep to the length specified by length. 212 */ 213 int 214 detrunc(struct denode *dep, u_long length, int flags, struct ucred *cred) 215 { 216 int error; 217 int allerror; 218 u_long eofentry; 219 u_long chaintofree; 220 daddr_t bn; 221 int boff; 222 int isadir = dep->de_Attributes & ATTR_DIRECTORY; 223 struct buf *bp; 224 struct msdosfsmount *pmp = dep->de_pmp; 225 226 MSDOSFS_DPRINTF(("detrunc(): file %s, length %lu, flags %x\n", 227 dep->de_Name, length, flags)); 228 229 /* 230 * Disallow attempts to truncate the root directory since it is of 231 * fixed size. That's just the way dos filesystems are. We use 232 * the VROOT bit in the vnode because checking for the directory 233 * bit and a startcluster of 0 in the denode is not adequate to 234 * recognize the root directory at this point in a file or 235 * directory's life. 236 */ 237 if (dep->de_vnode != NULL && !FAT32(pmp)) { 238 MSDOSFS_DPRINTF(("detrunc(): can't truncate root directory, " 239 "clust %ld, offset %ld\n", 240 dep->de_dirclust, dep->de_diroffset)); 241 242 return (EINVAL); 243 } 244 245 if (dep->de_FileSize < length) 246 return deextend(dep, length, cred); 247 248 /* 249 * If the desired length is 0 then remember the starting cluster of 250 * the file and set the StartCluster field in the directory entry 251 * to 0. If the desired length is not zero, then get the number of 252 * the last cluster in the shortened file. Then get the number of 253 * the first cluster in the part of the file that is to be freed. 254 * Then set the next cluster pointer in the last cluster of the 255 * file to CLUST_EOFE. 256 */ 257 if (length == 0) { 258 chaintofree = dep->de_StartCluster; 259 dep->de_StartCluster = 0; 260 eofentry = ~0; 261 } else { 262 error = pcbmap(dep, de_clcount(pmp, length) - 1, 0, 263 &eofentry, 0); 264 if (error) { 265 MSDOSFS_DPRINTF(("detrunc(): pcbmap fails %d\n", 266 error)); 267 return (error); 268 } 269 } 270 271 fc_purge(dep, de_clcount(pmp, length)); 272 273 /* 274 * If the new length is not a multiple of the cluster size then we 275 * must zero the tail end of the new last cluster in case it 276 * becomes part of the file again because of a seek. 277 */ 278 if ((boff = length & pmp->pm_crbomask) != 0) { 279 if (isadir) { 280 bn = cntobn(pmp, eofentry); 281 error = bread(pmp->pm_devvp, bn, pmp->pm_bpcluster, 282 0, &bp); 283 if (error) { 284 brelse(bp); 285 MSDOSFS_DPRINTF(("detrunc(): bread fails %d\n", 286 error)); 287 288 return (error); 289 } 290 memset(bp->b_data + boff, 0, pmp->pm_bpcluster - boff); 291 if (flags & IO_SYNC) 292 bwrite(bp); 293 else 294 bdwrite(bp); 295 } 296 } 297 298 /* 299 * Write out the updated directory entry. Even if the update fails 300 * we free the trailing clusters. 301 */ 302 dep->de_FileSize = length; 303 if (!isadir) 304 dep->de_flag |= DE_UPDATE|DE_MODIFIED; 305 MSDOSFS_DPRINTF(("detrunc(): allerror %d, eofentry %lu\n", 306 allerror, eofentry)); 307 308 /* 309 * If we need to break the cluster chain for the file then do it 310 * now. 311 */ 312 if (eofentry != ~0) { 313 error = fatentry(FAT_GET_AND_SET, pmp, eofentry, 314 &chaintofree, CLUST_EOFE); 315 if (error) { 316 MSDOSFS_DPRINTF(("detrunc(): fatentry errors %d\n", 317 error)); 318 return (error); 319 } 320 fc_setcache(dep, FC_LASTFC, de_cluster(pmp, length - 1), 321 eofentry); 322 } 323 324 /* 325 * Now free the clusters removed from the file because of the 326 * truncation. 327 */ 328 if (chaintofree != 0 && !MSDOSFSEOF(pmp, chaintofree)) 329 freeclusterchain(pmp, chaintofree); 330 331 return (allerror); 332 } 333 334 /* 335 * Extend the file described by dep to length specified by length. 336 */ 337 int 338 deextend(struct denode *dep, u_long length, struct ucred *cred) 339 { 340 struct msdosfsmount *pmp = dep->de_pmp; 341 u_long count; 342 int error; 343 344 /* 345 * The root of a DOS filesystem cannot be extended. 346 */ 347 if (dep->de_vnode != NULL && !FAT32(pmp)) 348 return (EINVAL); 349 350 /* 351 * Directories cannot be extended. 352 */ 353 if (dep->de_Attributes & ATTR_DIRECTORY) 354 return (EISDIR); 355 356 if (length <= dep->de_FileSize) 357 return (E2BIG); 358 359 /* 360 * Compute the number of clusters to allocate. 361 */ 362 count = de_clcount(pmp, length) - de_clcount(pmp, dep->de_FileSize); 363 if (count > 0) { 364 if (count > pmp->pm_freeclustercount) 365 return (ENOSPC); 366 error = extendfile(dep, count, NULL, NULL, DE_CLEAR); 367 if (error) { 368 /* truncate the added clusters away again */ 369 (void) detrunc(dep, dep->de_FileSize, 0, cred); 370 return (error); 371 } 372 } 373 374 /* 375 * Zero extend file range; ubc_zerorange() uses ubc_alloc() and a 376 * memset(); we set the write size so ubc won't read in file data that 377 * is zero'd later. 378 */ 379 dep->de_FileSize = length; 380 dep->de_flag |= DE_UPDATE | DE_MODIFIED; 381 return 0; 382 } 383