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