1 /* $OpenBSD: msdosfs_denode.c,v 1.7 2021/10/06 00:40:41 deraadt Exp $ */ 2 /* $NetBSD: msdosfs_denode.c,v 1.7 2015/03/29 05:52:59 agc Exp $ */ 3 4 /*- 5 * Copyright (C) 1994, 1995, 1997 Wolfgang Solfrank. 6 * Copyright (C) 1994, 1995, 1997 TooLs GmbH. 7 * All rights reserved. 8 * Original code by Paul Popelka (paulp@uts.amdahl.com) (see below). 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by TooLs GmbH. 21 * 4. The name of TooLs GmbH may not be used to endorse or promote products 22 * derived from this software without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``AS IS'' AND ANY EXPRESS OR 25 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 26 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 27 * IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 28 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 29 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; 30 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 31 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR 32 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF 33 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 34 */ 35 /* 36 * Written by Paul Popelka (paulp@uts.amdahl.com) 37 * 38 * You can do anything you want with this software, just don't say you wrote 39 * it, and don't remove this notice. 40 * 41 * This software is provided "as is". 42 * 43 * The author supplies this software to be publicly redistributed on the 44 * understanding that the author is not responsible for the correct 45 * functioning of this software in any circumstances and is not liable for 46 * any damages caused by this software. 47 * 48 * October 1992 49 */ 50 51 52 #include "ffs/buf.h" 53 54 #include <msdosfs/bpb.h> 55 #include "msdos/msdosfsmount.h" 56 #include "msdos/direntry.h" 57 #include "msdos/denode.h" 58 #include "msdos/fat.h" 59 60 #include <util.h> 61 62 #include "makefs.h" 63 64 /* 65 * If deget() succeeds it returns with the gotten denode locked(). 66 * 67 * pmp - address of msdosfsmount structure of the filesystem containing 68 * the denode of interest. The pm_dev field and the address of 69 * the msdosfsmount structure are used. 70 * dirclust - which cluster bp contains, if dirclust is 0 (root directory) 71 * diroffset is relative to the beginning of the root directory, 72 * otherwise it is cluster relative. 73 * diroffset - offset past begin of cluster of denode we want 74 * depp - returns the address of the gotten denode. 75 */ 76 int 77 deget(struct msdosfsmount *pmp, u_long dirclust, u_long diroffset, 78 struct denode **depp) 79 /* pmp: so we know the maj/min number */ 80 /* dirclust: cluster this dir entry came from */ 81 /* diroffset: index of entry within the cluster */ 82 /* depp: returns the addr of the gotten denode */ 83 { 84 int error; 85 struct direntry *direntptr; 86 struct denode *ldep; 87 struct mkfsbuf *bp; 88 89 #ifdef MSDOSFS_DEBUG 90 printf("deget(pmp %p, dirclust %lu, diroffset %lx, depp %p)\n", 91 pmp, dirclust, diroffset, depp); 92 #endif 93 94 /* 95 * On FAT32 filesystems, root is a (more or less) normal 96 * directory 97 */ 98 if (FAT32(pmp) && dirclust == MSDOSFSROOT) 99 dirclust = pmp->pm_rootdirblk; 100 101 ldep = ecalloc(1, sizeof(*ldep)); 102 ldep->de_mkfsvnode = NULL; 103 ldep->de_flag = 0; 104 ldep->de_devvp = 0; 105 ldep->de_lockf = 0; 106 ldep->de_dev = pmp->pm_dev; 107 ldep->de_dirclust = dirclust; 108 ldep->de_diroffset = diroffset; 109 ldep->de_pmp = pmp; 110 ldep->de_devvp = pmp->pm_devvp; 111 ldep->de_refcnt = 1; 112 fc_purge(ldep, 0); 113 /* 114 * Copy the directory entry into the denode area of the mkfsvnode. 115 */ 116 if ((dirclust == MSDOSFSROOT 117 || (FAT32(pmp) && dirclust == pmp->pm_rootdirblk)) 118 && diroffset == MSDOSFSROOT_OFS) { 119 /* 120 * Directory entry for the root directory. There isn't one, 121 * so we manufacture one. We should probably rummage 122 * through the root directory and find a label entry (if it 123 * exists), and then use the time and date from that entry 124 * as the time and date for the root denode. 125 */ 126 ldep->de_mkfsvnode = (struct mkfsvnode *)-1; 127 128 ldep->de_Attributes = ATTR_DIRECTORY; 129 if (FAT32(pmp)) 130 ldep->de_StartCluster = pmp->pm_rootdirblk; 131 /* de_FileSize will be filled in further down */ 132 else { 133 ldep->de_StartCluster = MSDOSFSROOT; 134 ldep->de_FileSize = pmp->pm_rootdirsize * pmp->pm_BytesPerSec; 135 } 136 /* 137 * fill in time and date so that dos2unixtime() doesn't 138 * spit up when called from msdosfs_getattr() with root 139 * denode 140 */ 141 ldep->de_CHun = 0; 142 ldep->de_CTime = 0x0000; /* 00:00:00 */ 143 ldep->de_CDate = (0 << DD_YEAR_SHIFT) | (1 << DD_MONTH_SHIFT) 144 | (1 << DD_DAY_SHIFT); 145 /* Jan 1, 1980 */ 146 ldep->de_ADate = ldep->de_CDate; 147 ldep->de_MTime = ldep->de_CTime; 148 ldep->de_MDate = ldep->de_CDate; 149 /* leave the other fields as garbage */ 150 } else { 151 error = readep(pmp, dirclust, diroffset, &bp, &direntptr); 152 if (error) { 153 ldep->de_devvp = NULL; 154 ldep->de_Name[0] = SLOT_DELETED; 155 return (error); 156 } 157 DE_INTERNALIZE(ldep, direntptr); 158 brelse(bp, 0); 159 } 160 161 /* 162 * Fill in a few fields of the mkfsvnode and finish filling in the 163 * denode. Then return the address of the found denode. 164 */ 165 if (ldep->de_Attributes & ATTR_DIRECTORY) { 166 /* 167 * Since DOS directory entries that describe directories 168 * have 0 in the filesize field, we take this opportunity 169 * to find out the length of the directory and plug it into 170 * the denode structure. 171 */ 172 u_long size; 173 174 if (ldep->de_StartCluster != MSDOSFSROOT) { 175 error = pcbmap(ldep, CLUST_END, 0, &size, 0); 176 if (error == E2BIG) { 177 ldep->de_FileSize = de_cn2off(pmp, size); 178 error = 0; 179 } else 180 printf("deget(): pcbmap returned %d\n", error); 181 } 182 } 183 *depp = ldep; 184 return (0); 185 } 186 187 /* 188 * Truncate the file described by dep to the length specified by length. 189 */ 190 int 191 detrunc(struct denode *dep, u_long length, int flags) 192 { 193 int error; 194 int allerror = 0; 195 u_long eofentry; 196 u_long chaintofree = 0; 197 daddr_t bn, lastblock; 198 int boff; 199 int isadir = dep->de_Attributes & ATTR_DIRECTORY; 200 struct mkfsbuf *bp; 201 struct msdosfsmount *pmp = dep->de_pmp; 202 203 #ifdef MSDOSFS_DEBUG 204 printf("detrunc(): file %s, length %lu, flags %x\n", dep->de_Name, length, flags); 205 #endif 206 207 /* 208 * Disallow attempts to truncate the root directory since it is of 209 * fixed size. That's just the way dos filesystems are. We use 210 * the VROOT bit in the mkfsvnode because checking for the directory 211 * bit and a startcluster of 0 in the denode is not adequate to 212 * recognize the root directory at this point in a file or 213 * directory's life. 214 */ 215 if (dep->de_mkfsvnode != NULL && !FAT32(pmp)) { 216 printf("detrunc(): can't truncate root directory, clust %ld, offset %ld\n", 217 dep->de_dirclust, dep->de_diroffset); 218 return (EINVAL); 219 } 220 221 if (dep->de_FileSize < length) 222 return (deextend(dep, length)); 223 lastblock = de_clcount(pmp, length) - 1; 224 225 /* 226 * If the desired length is 0 then remember the starting cluster of 227 * the file and set the StartCluster field in the directory entry 228 * to 0. If the desired length is not zero, then get the number of 229 * the last cluster in the shortened file. Then get the number of 230 * the first cluster in the part of the file that is to be freed. 231 * Then set the next cluster pointer in the last cluster of the 232 * file to CLUST_EOFE. 233 */ 234 if (length == 0) { 235 chaintofree = dep->de_StartCluster; 236 dep->de_StartCluster = 0; 237 eofentry = ~0; 238 } else { 239 error = pcbmap(dep, lastblock, 0, &eofentry, 0); 240 if (error) { 241 #ifdef MSDOSFS_DEBUG 242 printf("detrunc(): pcbmap fails %d\n", error); 243 #endif 244 return (error); 245 } 246 } 247 248 /* 249 * If the new length is not a multiple of the cluster size then we 250 * must zero the tail end of the new last cluster in case it 251 * becomes part of the file again because of a seek. 252 */ 253 if ((boff = length & pmp->pm_crbomask) != 0) { 254 if (isadir) { 255 bn = cntobn(pmp, eofentry); 256 error = bread(pmp->pm_devvp, de_bn2kb(pmp, bn), 257 pmp->pm_bpcluster, B_MODIFY, &bp); 258 if (error) { 259 #ifdef MSDOSFS_DEBUG 260 printf("detrunc(): bread fails %d\n", error); 261 #endif 262 return (error); 263 } 264 memset((char *)bp->b_data + boff, 0, 265 pmp->pm_bpcluster - boff); 266 if (flags & IO_SYNC) 267 bwrite(bp); 268 else 269 bdwrite(bp); 270 } 271 } 272 273 /* 274 * Write out the updated directory entry. Even if the update fails 275 * we free the trailing clusters. 276 */ 277 dep->de_FileSize = length; 278 if (!isadir) 279 dep->de_flag |= DE_UPDATE|DE_MODIFIED; 280 #ifdef MSDOSFS_DEBUG 281 printf("detrunc(): allerror %d, eofentry %lu\n", 282 allerror, eofentry); 283 #endif 284 285 /* 286 * If we need to break the cluster chain for the file then do it 287 * now. 288 */ 289 if (eofentry != (u_long)~0) { 290 error = fatentry(FAT_GET_AND_SET, pmp, eofentry, 291 &chaintofree, CLUST_EOFE); 292 if (error) { 293 #ifdef MSDOSFS_DEBUG 294 printf("detrunc(): fatentry errors %d\n", error); 295 #endif 296 return (error); 297 } 298 } 299 300 /* 301 * Now free the clusters removed from the file because of the 302 * truncation. 303 */ 304 if (chaintofree != 0 && !MSDOSFSEOF(chaintofree, pmp->pm_fatmask)) 305 freeclusterchain(pmp, chaintofree); 306 307 return (allerror); 308 } 309 310 /* 311 * Extend the file described by dep to length specified by length. 312 */ 313 int 314 deextend(struct denode *dep, u_long length) 315 { 316 struct msdosfsmount *pmp = dep->de_pmp; 317 u_long count; 318 int error; 319 320 /* 321 * The root of a DOS filesystem cannot be extended. 322 */ 323 if (dep->de_mkfsvnode != NULL && !FAT32(pmp)) 324 return EINVAL; 325 326 /* 327 * Directories cannot be extended. 328 */ 329 if (dep->de_Attributes & ATTR_DIRECTORY) 330 return EISDIR; 331 332 if (length <= dep->de_FileSize) 333 return E2BIG; 334 335 /* 336 * Compute the number of clusters to allocate. 337 */ 338 count = de_clcount(pmp, length) - de_clcount(pmp, dep->de_FileSize); 339 if (count > 0) { 340 if (count > pmp->pm_freeclustercount) 341 return (ENOSPC); 342 error = extendfile(dep, count, NULL, NULL, DE_CLEAR); 343 if (error) { 344 /* truncate the added clusters away again */ 345 (void) detrunc(dep, dep->de_FileSize, 0); 346 return (error); 347 } 348 } 349 350 /* 351 * Zero extend file range; ubc_zerorange() uses ubc_alloc() and a 352 * memset(); we set the write size so ubc won't read in file data that 353 * is zero'd later. 354 */ 355 dep->de_FileSize = length; 356 dep->de_flag |= DE_UPDATE|DE_MODIFIED; 357 return 0; 358 } 359