1 /* $OpenBSD: msdosfs_denode.c,v 1.6 2016/10/22 22:20:24 natano 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 #include <sys/param.h> 52 53 #include "ffs/buf.h" 54 55 #include <msdosfs/bpb.h> 56 #include "msdos/msdosfsmount.h" 57 #include "msdos/direntry.h" 58 #include "msdos/denode.h" 59 #include "msdos/fat.h" 60 61 #include <util.h> 62 63 #include "makefs.h" 64 65 /* 66 * If deget() succeeds it returns with the gotten denode locked(). 67 * 68 * pmp - address of msdosfsmount structure of the filesystem containing 69 * the denode of interest. The pm_dev field and the address of 70 * the msdosfsmount structure are used. 71 * dirclust - which cluster bp contains, if dirclust is 0 (root directory) 72 * diroffset is relative to the beginning of the root directory, 73 * otherwise it is cluster relative. 74 * diroffset - offset past begin of cluster of denode we want 75 * depp - returns the address of the gotten denode. 76 */ 77 int 78 deget(struct msdosfsmount *pmp, u_long dirclust, u_long diroffset, 79 struct denode **depp) 80 /* pmp: so we know the maj/min number */ 81 /* dirclust: cluster this dir entry came from */ 82 /* diroffset: index of entry within the cluster */ 83 /* depp: returns the addr of the gotten denode */ 84 { 85 int error; 86 struct direntry *direntptr; 87 struct denode *ldep; 88 struct mkfsbuf *bp; 89 90 #ifdef MSDOSFS_DEBUG 91 printf("deget(pmp %p, dirclust %lu, diroffset %lx, depp %p)\n", 92 pmp, dirclust, diroffset, depp); 93 #endif 94 95 /* 96 * On FAT32 filesystems, root is a (more or less) normal 97 * directory 98 */ 99 if (FAT32(pmp) && dirclust == MSDOSFSROOT) 100 dirclust = pmp->pm_rootdirblk; 101 102 ldep = ecalloc(1, sizeof(*ldep)); 103 ldep->de_mkfsvnode = NULL; 104 ldep->de_flag = 0; 105 ldep->de_devvp = 0; 106 ldep->de_lockf = 0; 107 ldep->de_dev = pmp->pm_dev; 108 ldep->de_dirclust = dirclust; 109 ldep->de_diroffset = diroffset; 110 ldep->de_pmp = pmp; 111 ldep->de_devvp = pmp->pm_devvp; 112 ldep->de_refcnt = 1; 113 fc_purge(ldep, 0); 114 /* 115 * Copy the directory entry into the denode area of the mkfsvnode. 116 */ 117 if ((dirclust == MSDOSFSROOT 118 || (FAT32(pmp) && dirclust == pmp->pm_rootdirblk)) 119 && diroffset == MSDOSFSROOT_OFS) { 120 /* 121 * Directory entry for the root directory. There isn't one, 122 * so we manufacture one. We should probably rummage 123 * through the root directory and find a label entry (if it 124 * exists), and then use the time and date from that entry 125 * as the time and date for the root denode. 126 */ 127 ldep->de_mkfsvnode = (struct mkfsvnode *)-1; 128 129 ldep->de_Attributes = ATTR_DIRECTORY; 130 if (FAT32(pmp)) 131 ldep->de_StartCluster = pmp->pm_rootdirblk; 132 /* de_FileSize will be filled in further down */ 133 else { 134 ldep->de_StartCluster = MSDOSFSROOT; 135 ldep->de_FileSize = pmp->pm_rootdirsize * pmp->pm_BytesPerSec; 136 } 137 /* 138 * fill in time and date so that dos2unixtime() doesn't 139 * spit up when called from msdosfs_getattr() with root 140 * denode 141 */ 142 ldep->de_CHun = 0; 143 ldep->de_CTime = 0x0000; /* 00:00:00 */ 144 ldep->de_CDate = (0 << DD_YEAR_SHIFT) | (1 << DD_MONTH_SHIFT) 145 | (1 << DD_DAY_SHIFT); 146 /* Jan 1, 1980 */ 147 ldep->de_ADate = ldep->de_CDate; 148 ldep->de_MTime = ldep->de_CTime; 149 ldep->de_MDate = ldep->de_CDate; 150 /* leave the other fields as garbage */ 151 } else { 152 error = readep(pmp, dirclust, diroffset, &bp, &direntptr); 153 if (error) { 154 ldep->de_devvp = NULL; 155 ldep->de_Name[0] = SLOT_DELETED; 156 return (error); 157 } 158 DE_INTERNALIZE(ldep, direntptr); 159 brelse(bp, 0); 160 } 161 162 /* 163 * Fill in a few fields of the mkfsvnode and finish filling in the 164 * denode. Then return the address of the found denode. 165 */ 166 if (ldep->de_Attributes & ATTR_DIRECTORY) { 167 /* 168 * Since DOS directory entries that describe directories 169 * have 0 in the filesize field, we take this opportunity 170 * to find out the length of the directory and plug it into 171 * the denode structure. 172 */ 173 u_long size; 174 175 if (ldep->de_StartCluster != MSDOSFSROOT) { 176 error = pcbmap(ldep, CLUST_END, 0, &size, 0); 177 if (error == E2BIG) { 178 ldep->de_FileSize = de_cn2off(pmp, size); 179 error = 0; 180 } else 181 printf("deget(): pcbmap returned %d\n", error); 182 } 183 } 184 *depp = ldep; 185 return (0); 186 } 187 188 /* 189 * Truncate the file described by dep to the length specified by length. 190 */ 191 int 192 detrunc(struct denode *dep, u_long length, int flags) 193 { 194 int error; 195 int allerror = 0; 196 u_long eofentry; 197 u_long chaintofree = 0; 198 daddr_t bn, lastblock; 199 int boff; 200 int isadir = dep->de_Attributes & ATTR_DIRECTORY; 201 struct mkfsbuf *bp; 202 struct msdosfsmount *pmp = dep->de_pmp; 203 204 #ifdef MSDOSFS_DEBUG 205 printf("detrunc(): file %s, length %lu, flags %x\n", dep->de_Name, length, flags); 206 #endif 207 208 /* 209 * Disallow attempts to truncate the root directory since it is of 210 * fixed size. That's just the way dos filesystems are. We use 211 * the VROOT bit in the mkfsvnode because checking for the directory 212 * bit and a startcluster of 0 in the denode is not adequate to 213 * recognize the root directory at this point in a file or 214 * directory's life. 215 */ 216 if (dep->de_mkfsvnode != NULL && !FAT32(pmp)) { 217 printf("detrunc(): can't truncate root directory, clust %ld, offset %ld\n", 218 dep->de_dirclust, dep->de_diroffset); 219 return (EINVAL); 220 } 221 222 if (dep->de_FileSize < length) 223 return (deextend(dep, length)); 224 lastblock = de_clcount(pmp, length) - 1; 225 226 /* 227 * If the desired length is 0 then remember the starting cluster of 228 * the file and set the StartCluster field in the directory entry 229 * to 0. If the desired length is not zero, then get the number of 230 * the last cluster in the shortened file. Then get the number of 231 * the first cluster in the part of the file that is to be freed. 232 * Then set the next cluster pointer in the last cluster of the 233 * file to CLUST_EOFE. 234 */ 235 if (length == 0) { 236 chaintofree = dep->de_StartCluster; 237 dep->de_StartCluster = 0; 238 eofentry = ~0; 239 } else { 240 error = pcbmap(dep, lastblock, 0, &eofentry, 0); 241 if (error) { 242 #ifdef MSDOSFS_DEBUG 243 printf("detrunc(): pcbmap fails %d\n", error); 244 #endif 245 return (error); 246 } 247 } 248 249 /* 250 * If the new length is not a multiple of the cluster size then we 251 * must zero the tail end of the new last cluster in case it 252 * becomes part of the file again because of a seek. 253 */ 254 if ((boff = length & pmp->pm_crbomask) != 0) { 255 if (isadir) { 256 bn = cntobn(pmp, eofentry); 257 error = bread(pmp->pm_devvp, de_bn2kb(pmp, bn), 258 pmp->pm_bpcluster, B_MODIFY, &bp); 259 if (error) { 260 #ifdef MSDOSFS_DEBUG 261 printf("detrunc(): bread fails %d\n", error); 262 #endif 263 return (error); 264 } 265 memset((char *)bp->b_data + boff, 0, 266 pmp->pm_bpcluster - boff); 267 if (flags & IO_SYNC) 268 bwrite(bp); 269 else 270 bdwrite(bp); 271 } 272 } 273 274 /* 275 * Write out the updated directory entry. Even if the update fails 276 * we free the trailing clusters. 277 */ 278 dep->de_FileSize = length; 279 if (!isadir) 280 dep->de_flag |= DE_UPDATE|DE_MODIFIED; 281 #ifdef MSDOSFS_DEBUG 282 printf("detrunc(): allerror %d, eofentry %lu\n", 283 allerror, eofentry); 284 #endif 285 286 /* 287 * If we need to break the cluster chain for the file then do it 288 * now. 289 */ 290 if (eofentry != (u_long)~0) { 291 error = fatentry(FAT_GET_AND_SET, pmp, eofentry, 292 &chaintofree, CLUST_EOFE); 293 if (error) { 294 #ifdef MSDOSFS_DEBUG 295 printf("detrunc(): fatentry errors %d\n", error); 296 #endif 297 return (error); 298 } 299 } 300 301 /* 302 * Now free the clusters removed from the file because of the 303 * truncation. 304 */ 305 if (chaintofree != 0 && !MSDOSFSEOF(chaintofree, pmp->pm_fatmask)) 306 freeclusterchain(pmp, chaintofree); 307 308 return (allerror); 309 } 310 311 /* 312 * Extend the file described by dep to length specified by length. 313 */ 314 int 315 deextend(struct denode *dep, u_long length) 316 { 317 struct msdosfsmount *pmp = dep->de_pmp; 318 u_long count; 319 int error; 320 321 /* 322 * The root of a DOS filesystem cannot be extended. 323 */ 324 if (dep->de_mkfsvnode != NULL && !FAT32(pmp)) 325 return EINVAL; 326 327 /* 328 * Directories cannot be extended. 329 */ 330 if (dep->de_Attributes & ATTR_DIRECTORY) 331 return EISDIR; 332 333 if (length <= dep->de_FileSize) 334 return E2BIG; 335 336 /* 337 * Compute the number of clusters to allocate. 338 */ 339 count = de_clcount(pmp, length) - de_clcount(pmp, dep->de_FileSize); 340 if (count > 0) { 341 if (count > pmp->pm_freeclustercount) 342 return (ENOSPC); 343 error = extendfile(dep, count, NULL, NULL, DE_CLEAR); 344 if (error) { 345 /* truncate the added clusters away again */ 346 (void) detrunc(dep, dep->de_FileSize, 0); 347 return (error); 348 } 349 } 350 351 /* 352 * Zero extend file range; ubc_zerorange() uses ubc_alloc() and a 353 * memset(); we set the write size so ubc won't read in file data that 354 * is zero'd later. 355 */ 356 dep->de_FileSize = length; 357 dep->de_flag |= DE_UPDATE|DE_MODIFIED; 358 return 0; 359 } 360