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 <stdio.h> 60 #include <string.h> 61 #include <stdlib.h> 62 #include <util.h> 63 64 #include "ffs/buf.h" 65 66 #include <fs/msdosfs/bpb.h> 67 #include <fs/msdosfs/direntry.h> 68 #include <fs/msdosfs/denode.h> 69 #include <fs/msdosfs/fat.h> 70 #include "msdos/msdosfsmount.h" 71 72 #include "makefs.h" 73 #include "msdos.h" 74 75 76 /* 77 * If deget() succeeds it returns with the gotten denode locked(). 78 * 79 * pmp - address of msdosfsmount structure of the filesystem containing 80 * the denode of interest. The pm_dev field and the address of 81 * the msdosfsmount structure are used. 82 * dirclust - which cluster bp contains, if dirclust is 0 (root directory) 83 * diroffset is relative to the beginning of the root directory, 84 * otherwise it is cluster relative. 85 * diroffset - offset past begin of cluster of denode we want 86 * depp - returns the address of the gotten denode. 87 */ 88 int 89 deget(struct msdosfsmount *pmp, u_long dirclust, u_long diroffset, 90 struct denode **depp) 91 { 92 int error; 93 uint64_t inode; 94 struct direntry *direntptr; 95 struct denode *ldep; 96 struct buf *bp; 97 98 MSDOSFS_DPRINTF(("deget(pmp %p, dirclust %lu, diroffset %lx, depp %p)\n", 99 pmp, dirclust, diroffset, depp)); 100 101 /* 102 * On FAT32 filesystems, root is a (more or less) normal 103 * directory 104 */ 105 if (FAT32(pmp) && dirclust == MSDOSFSROOT) 106 dirclust = pmp->pm_rootdirblk; 107 108 inode = (uint64_t)pmp->pm_bpcluster * dirclust + diroffset; 109 110 ldep = ecalloc(1, sizeof(*ldep)); 111 ldep->de_vnode = NULL; 112 ldep->de_flag = 0; 113 ldep->de_dirclust = dirclust; 114 ldep->de_diroffset = diroffset; 115 ldep->de_inode = inode; 116 ldep->de_pmp = pmp; 117 ldep->de_refcnt = 1; 118 fc_purge(ldep, 0); /* init the FAT cache for this denode */ 119 /* 120 * Copy the directory entry into the denode area of the vnode. 121 */ 122 if ((dirclust == MSDOSFSROOT 123 || (FAT32(pmp) && dirclust == pmp->pm_rootdirblk)) 124 && diroffset == MSDOSFSROOT_OFS) { 125 /* 126 * Directory entry for the root directory. There isn't one, 127 * so we manufacture one. We should probably rummage 128 * through the root directory and find a label entry (if it 129 * exists), and then use the time and date from that entry 130 * as the time and date for the root denode. 131 */ 132 ldep->de_vnode = (struct vnode *)-1; 133 134 ldep->de_Attributes = ATTR_DIRECTORY; 135 ldep->de_LowerCase = 0; 136 if (FAT32(pmp)) 137 ldep->de_StartCluster = pmp->pm_rootdirblk; 138 /* de_FileSize will be filled in further down */ 139 else { 140 ldep->de_StartCluster = MSDOSFSROOT; 141 ldep->de_FileSize = pmp->pm_rootdirsize * DEV_BSIZE; 142 } 143 /* 144 * fill in time and date so that dos2unixtime() doesn't 145 * spit up when called from msdosfs_getattr() with root 146 * denode 147 */ 148 ldep->de_CHun = 0; 149 ldep->de_CTime = 0x0000; /* 00:00:00 */ 150 ldep->de_CDate = (0 << DD_YEAR_SHIFT) | (1 << DD_MONTH_SHIFT) 151 | (1 << DD_DAY_SHIFT); 152 /* Jan 1, 1980 */ 153 ldep->de_ADate = ldep->de_CDate; 154 ldep->de_MTime = ldep->de_CTime; 155 ldep->de_MDate = ldep->de_CDate; 156 /* leave the other fields as garbage */ 157 } else { 158 error = readep(pmp, dirclust, diroffset, &bp, &direntptr); 159 if (error) { 160 ldep->de_Name[0] = SLOT_DELETED; 161 162 *depp = NULL; 163 return (error); 164 } 165 (void)DE_INTERNALIZE(ldep, direntptr); 166 brelse(bp); 167 } 168 169 /* 170 * Fill in a few fields of the vnode and finish filling in the 171 * denode. Then return the address of the found denode. 172 */ 173 if (ldep->de_Attributes & ATTR_DIRECTORY) { 174 /* 175 * Since DOS directory entries that describe directories 176 * have 0 in the filesize field, we take this opportunity 177 * to find out the length of the directory and plug it into 178 * the denode structure. 179 */ 180 u_long size; 181 182 /* 183 * XXX it sometimes happens that the "." entry has cluster 184 * number 0 when it shouldn't. Use the actual cluster number 185 * instead of what is written in directory entry. 186 */ 187 if (diroffset == 0 && ldep->de_StartCluster != dirclust) { 188 MSDOSFS_DPRINTF(("deget(): \".\" entry at clust %lu != %lu\n", 189 dirclust, ldep->de_StartCluster)); 190 191 ldep->de_StartCluster = dirclust; 192 } 193 194 if (ldep->de_StartCluster != MSDOSFSROOT) { 195 error = pcbmap(ldep, 0xffff, 0, &size, 0); 196 if (error == E2BIG) { 197 ldep->de_FileSize = de_cn2off(pmp, size); 198 error = 0; 199 } else { 200 MSDOSFS_DPRINTF(("deget(): pcbmap returned %d\n", 201 error)); 202 } 203 } 204 } 205 *depp = ldep; 206 return (0); 207 } 208 209 /* 210 * Truncate the file described by dep to the length specified by length. 211 */ 212 int 213 detrunc(struct denode *dep, u_long length, int flags, struct ucred *cred) 214 { 215 int error; 216 int allerror; 217 u_long eofentry; 218 u_long chaintofree; 219 daddr_t bn; 220 int boff; 221 int isadir = dep->de_Attributes & ATTR_DIRECTORY; 222 struct buf *bp; 223 struct msdosfsmount *pmp = dep->de_pmp; 224 225 MSDOSFS_DPRINTF(("detrunc(): file %s, length %lu, flags %x\n", 226 dep->de_Name, length, flags)); 227 228 /* 229 * Disallow attempts to truncate the root directory since it is of 230 * fixed size. That's just the way dos filesystems are. We use 231 * the VROOT bit in the vnode because checking for the directory 232 * bit and a startcluster of 0 in the denode is not adequate to 233 * recognize the root directory at this point in a file or 234 * directory's life. 235 */ 236 if (dep->de_vnode != NULL && !FAT32(pmp)) { 237 MSDOSFS_DPRINTF(("detrunc(): can't truncate root directory, " 238 "clust %ld, offset %ld\n", 239 dep->de_dirclust, dep->de_diroffset)); 240 241 return (EINVAL); 242 } 243 244 if (dep->de_FileSize < length) 245 return deextend(dep, length, cred); 246 247 /* 248 * If the desired length is 0 then remember the starting cluster of 249 * the file and set the StartCluster field in the directory entry 250 * to 0. If the desired length is not zero, then get the number of 251 * the last cluster in the shortened file. Then get the number of 252 * the first cluster in the part of the file that is to be freed. 253 * Then set the next cluster pointer in the last cluster of the 254 * file to CLUST_EOFE. 255 */ 256 if (length == 0) { 257 chaintofree = dep->de_StartCluster; 258 dep->de_StartCluster = 0; 259 eofentry = ~0; 260 } else { 261 error = pcbmap(dep, de_clcount(pmp, length) - 1, 0, 262 &eofentry, 0); 263 if (error) { 264 MSDOSFS_DPRINTF(("detrunc(): pcbmap fails %d\n", 265 error)); 266 return (error); 267 } 268 } 269 270 fc_purge(dep, de_clcount(pmp, length)); 271 272 /* 273 * If the new length is not a multiple of the cluster size then we 274 * must zero the tail end of the new last cluster in case it 275 * becomes part of the file again because of a seek. 276 */ 277 if ((boff = length & pmp->pm_crbomask) != 0) { 278 if (isadir) { 279 bn = cntobn(pmp, eofentry); 280 error = bread(pmp->pm_devvp, bn, pmp->pm_bpcluster, 281 0, &bp); 282 if (error) { 283 brelse(bp); 284 MSDOSFS_DPRINTF(("detrunc(): bread fails %d\n", 285 error)); 286 287 return (error); 288 } 289 memset(bp->b_data + boff, 0, pmp->pm_bpcluster - boff); 290 if (flags & IO_SYNC) 291 bwrite(bp); 292 else 293 bdwrite(bp); 294 } 295 } 296 297 /* 298 * Write out the updated directory entry. Even if the update fails 299 * we free the trailing clusters. 300 */ 301 dep->de_FileSize = length; 302 if (!isadir) 303 dep->de_flag |= DE_UPDATE|DE_MODIFIED; 304 MSDOSFS_DPRINTF(("detrunc(): allerror %d, eofentry %lu\n", 305 allerror, eofentry)); 306 307 /* 308 * If we need to break the cluster chain for the file then do it 309 * now. 310 */ 311 if (eofentry != ~0) { 312 error = fatentry(FAT_GET_AND_SET, pmp, eofentry, 313 &chaintofree, CLUST_EOFE); 314 if (error) { 315 MSDOSFS_DPRINTF(("detrunc(): fatentry errors %d\n", 316 error)); 317 return (error); 318 } 319 fc_setcache(dep, FC_LASTFC, de_cluster(pmp, length - 1), 320 eofentry); 321 } 322 323 /* 324 * Now free the clusters removed from the file because of the 325 * truncation. 326 */ 327 if (chaintofree != 0 && !MSDOSFSEOF(pmp, chaintofree)) 328 freeclusterchain(pmp, chaintofree); 329 330 return (allerror); 331 } 332 333 /* 334 * Extend the file described by dep to length specified by length. 335 */ 336 int 337 deextend(struct denode *dep, u_long length, struct ucred *cred) 338 { 339 struct msdosfsmount *pmp = dep->de_pmp; 340 u_long count; 341 int error; 342 343 /* 344 * The root of a DOS filesystem cannot be extended. 345 */ 346 if (dep->de_vnode != NULL && !FAT32(pmp)) 347 return (EINVAL); 348 349 /* 350 * Directories cannot be extended. 351 */ 352 if (dep->de_Attributes & ATTR_DIRECTORY) 353 return (EISDIR); 354 355 if (length <= dep->de_FileSize) 356 return (E2BIG); 357 358 /* 359 * Compute the number of clusters to allocate. 360 */ 361 count = de_clcount(pmp, length) - de_clcount(pmp, dep->de_FileSize); 362 if (count > 0) { 363 if (count > pmp->pm_freeclustercount) 364 return (ENOSPC); 365 error = extendfile(dep, count, NULL, NULL, DE_CLEAR); 366 if (error) { 367 /* truncate the added clusters away again */ 368 (void) detrunc(dep, dep->de_FileSize, 0, cred); 369 return (error); 370 } 371 } 372 373 /* 374 * Zero extend file range; ubc_zerorange() uses ubc_alloc() and a 375 * memset(); we set the write size so ubc won't read in file data that 376 * is zero'd later. 377 */ 378 dep->de_FileSize = length; 379 dep->de_flag |= DE_UPDATE | DE_MODIFIED; 380 return 0; 381 } 382