1 /* $NetBSD: msdosfs_denode.c,v 1.7 2015/03/29 05:52:59 agc Exp $ */ 2 3 /*- 4 * Copyright (C) 1994, 1995, 1997 Wolfgang Solfrank. 5 * Copyright (C) 1994, 1995, 1997 TooLs GmbH. 6 * All rights reserved. 7 * Original code by Paul Popelka (paulp@uts.amdahl.com) (see below). 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 3. All advertising materials mentioning features or use of this software 18 * must display the following acknowledgement: 19 * This product includes software developed by TooLs GmbH. 20 * 4. The name of TooLs GmbH may not be used to endorse or promote products 21 * derived from this software without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``AS IS'' AND ANY EXPRESS OR 24 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 25 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 26 * IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 27 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 28 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; 29 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 30 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR 31 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF 32 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 33 */ 34 /* 35 * Written by Paul Popelka (paulp@uts.amdahl.com) 36 * 37 * You can do anything you want with this software, just don't say you wrote 38 * it, and don't remove this notice. 39 * 40 * This software is provided "as is". 41 * 42 * The author supplies this software to be publicly redistributed on the 43 * understanding that the author is not responsible for the correct 44 * functioning of this software in any circumstances and is not liable for 45 * any damages caused by this software. 46 * 47 * October 1992 48 */ 49 50 #if HAVE_NBTOOL_CONFIG_H 51 #include "nbtool_config.h" 52 #endif 53 54 #include <sys/cdefs.h> 55 __FBSDID("$FreeBSD$"); 56 57 #include <sys/param.h> 58 59 #include <ffs/buf.h> 60 61 #include <fs/msdosfs/bpb.h> 62 #include <fs/msdosfs/msdosfsmount.h> 63 #include <fs/msdosfs/direntry.h> 64 #include <fs/msdosfs/denode.h> 65 #include <fs/msdosfs/fat.h> 66 67 #include <util.h> 68 69 /* 70 * If deget() succeeds it returns with the gotten denode locked(). 71 * 72 * pmp - address of msdosfsmount structure of the filesystem containing 73 * the denode of interest. The pm_dev field and the address of 74 * the msdosfsmount structure are used. 75 * dirclust - which cluster bp contains, if dirclust is 0 (root directory) 76 * diroffset is relative to the beginning of the root directory, 77 * otherwise it is cluster relative. 78 * diroffset - offset past begin of cluster of denode we want 79 * depp - returns the address of the gotten denode. 80 */ 81 int 82 deget(struct msdosfsmount *pmp, u_long dirclust, u_long diroffset, 83 struct denode **depp) 84 /* pmp: so we know the maj/min number */ 85 /* dirclust: cluster this dir entry came from */ 86 /* diroffset: index of entry within the cluster */ 87 /* depp: returns the addr of the gotten denode */ 88 { 89 int error; 90 struct direntry *direntptr; 91 struct denode *ldep; 92 struct buf *bp; 93 94 #ifdef MSDOSFS_DEBUG 95 printf("deget(pmp %p, dirclust %lu, diroffset %lx, depp %p)\n", 96 pmp, dirclust, diroffset, depp); 97 #endif 98 99 /* 100 * On FAT32 filesystems, root is a (more or less) normal 101 * directory 102 */ 103 if (FAT32(pmp) && dirclust == MSDOSFSROOT) 104 dirclust = pmp->pm_rootdirblk; 105 106 ldep = ecalloc(1, sizeof(*ldep)); 107 ldep->de_vnode = NULL; 108 ldep->de_flag = 0; 109 ldep->de_devvp = 0; 110 ldep->de_lockf = 0; 111 ldep->de_dev = pmp->pm_dev; 112 ldep->de_dirclust = dirclust; 113 ldep->de_diroffset = diroffset; 114 ldep->de_pmp = pmp; 115 ldep->de_devvp = pmp->pm_devvp; 116 ldep->de_refcnt = 1; 117 fc_purge(ldep, 0); 118 /* 119 * Copy the directory entry into the denode area of the vnode. 120 */ 121 if ((dirclust == MSDOSFSROOT 122 || (FAT32(pmp) && dirclust == pmp->pm_rootdirblk)) 123 && diroffset == MSDOSFSROOT_OFS) { 124 /* 125 * Directory entry for the root directory. There isn't one, 126 * so we manufacture one. We should probably rummage 127 * through the root directory and find a label entry (if it 128 * exists), and then use the time and date from that entry 129 * as the time and date for the root denode. 130 */ 131 ldep->de_vnode = (struct vnode *)-1; 132 133 ldep->de_Attributes = ATTR_DIRECTORY; 134 if (FAT32(pmp)) 135 ldep->de_StartCluster = pmp->pm_rootdirblk; 136 /* de_FileSize will be filled in further down */ 137 else { 138 ldep->de_StartCluster = MSDOSFSROOT; 139 ldep->de_FileSize = pmp->pm_rootdirsize * pmp->pm_BytesPerSec; 140 } 141 /* 142 * fill in time and date so that dos2unixtime() doesn't 143 * spit up when called from msdosfs_getattr() with root 144 * denode 145 */ 146 ldep->de_CHun = 0; 147 ldep->de_CTime = 0x0000; /* 00:00:00 */ 148 ldep->de_CDate = (0 << DD_YEAR_SHIFT) | (1 << DD_MONTH_SHIFT) 149 | (1 << DD_DAY_SHIFT); 150 /* Jan 1, 1980 */ 151 ldep->de_ADate = ldep->de_CDate; 152 ldep->de_MTime = ldep->de_CTime; 153 ldep->de_MDate = ldep->de_CDate; 154 /* leave the other fields as garbage */ 155 } else { 156 error = readep(pmp, dirclust, diroffset, &bp, &direntptr); 157 if (error) { 158 ldep->de_devvp = NULL; 159 ldep->de_Name[0] = SLOT_DELETED; 160 return (error); 161 } 162 DE_INTERNALIZE(ldep, direntptr); 163 brelse(bp, 0); 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 if (ldep->de_StartCluster != MSDOSFSROOT) { 180 error = pcbmap(ldep, CLUST_END, 0, &size, 0); 181 if (error == E2BIG) { 182 ldep->de_FileSize = de_cn2off(pmp, size); 183 error = 0; 184 } else 185 printf("deget(): pcbmap returned %d\n", error); 186 } 187 } 188 *depp = ldep; 189 return (0); 190 } 191 192 /* 193 * Truncate the file described by dep to the length specified by length. 194 */ 195 int 196 detrunc(struct denode *dep, u_long length, int flags, struct kauth_cred *cred) 197 { 198 int error; 199 int allerror = 0; 200 u_long eofentry; 201 u_long chaintofree = 0; 202 daddr_t bn, lastblock; 203 int boff; 204 int isadir = dep->de_Attributes & ATTR_DIRECTORY; 205 struct buf *bp; 206 struct msdosfsmount *pmp = dep->de_pmp; 207 208 #ifdef MSDOSFS_DEBUG 209 printf("detrunc(): file %s, length %lu, flags %x\n", dep->de_Name, length, flags); 210 #endif 211 212 /* 213 * Disallow attempts to truncate the root directory since it is of 214 * fixed size. That's just the way dos filesystems are. We use 215 * the VROOT bit in the vnode because checking for the directory 216 * bit and a startcluster of 0 in the denode is not adequate to 217 * recognize the root directory at this point in a file or 218 * directory's life. 219 */ 220 if (dep->de_vnode != NULL && !FAT32(pmp)) { 221 printf("detrunc(): can't truncate root directory, clust %ld, offset %ld\n", 222 dep->de_dirclust, dep->de_diroffset); 223 return (EINVAL); 224 } 225 226 if (dep->de_FileSize < length) 227 return (deextend(dep, length, cred)); 228 lastblock = de_clcount(pmp, length) - 1; 229 230 /* 231 * If the desired length is 0 then remember the starting cluster of 232 * the file and set the StartCluster field in the directory entry 233 * to 0. If the desired length is not zero, then get the number of 234 * the last cluster in the shortened file. Then get the number of 235 * the first cluster in the part of the file that is to be freed. 236 * Then set the next cluster pointer in the last cluster of the 237 * file to CLUST_EOFE. 238 */ 239 if (length == 0) { 240 chaintofree = dep->de_StartCluster; 241 dep->de_StartCluster = 0; 242 eofentry = ~0; 243 } else { 244 error = pcbmap(dep, lastblock, 0, &eofentry, 0); 245 if (error) { 246 #ifdef MSDOSFS_DEBUG 247 printf("detrunc(): pcbmap fails %d\n", error); 248 #endif 249 return (error); 250 } 251 } 252 253 /* 254 * If the new length is not a multiple of the cluster size then we 255 * must zero the tail end of the new last cluster in case it 256 * becomes part of the file again because of a seek. 257 */ 258 if ((boff = length & pmp->pm_crbomask) != 0) { 259 if (isadir) { 260 bn = cntobn(pmp, eofentry); 261 error = bread(pmp->pm_devvp, de_bn2kb(pmp, bn), 262 pmp->pm_bpcluster, B_MODIFY, &bp); 263 if (error) { 264 #ifdef MSDOSFS_DEBUG 265 printf("detrunc(): bread fails %d\n", error); 266 #endif 267 return (error); 268 } 269 memset((char *)bp->b_data + boff, 0, 270 pmp->pm_bpcluster - boff); 271 if (flags & IO_SYNC) 272 bwrite(bp); 273 else 274 bdwrite(bp); 275 } 276 } 277 278 /* 279 * Write out the updated directory entry. Even if the update fails 280 * we free the trailing clusters. 281 */ 282 dep->de_FileSize = length; 283 if (!isadir) 284 dep->de_flag |= DE_UPDATE|DE_MODIFIED; 285 #ifdef MSDOSFS_DEBUG 286 printf("detrunc(): allerror %d, eofentry %lu\n", 287 allerror, eofentry); 288 #endif 289 290 /* 291 * If we need to break the cluster chain for the file then do it 292 * now. 293 */ 294 if (eofentry != (u_long)~0) { 295 error = fatentry(FAT_GET_AND_SET, pmp, eofentry, 296 &chaintofree, CLUST_EOFE); 297 if (error) { 298 #ifdef MSDOSFS_DEBUG 299 printf("detrunc(): fatentry errors %d\n", error); 300 #endif 301 return (error); 302 } 303 } 304 305 /* 306 * Now free the clusters removed from the file because of the 307 * truncation. 308 */ 309 if (chaintofree != 0 && !MSDOSFSEOF(chaintofree, pmp->pm_fatmask)) 310 freeclusterchain(pmp, chaintofree); 311 312 return (allerror); 313 } 314 315 /* 316 * Extend the file described by dep to length specified by length. 317 */ 318 int 319 deextend(struct denode *dep, u_long length, struct kauth_cred *cred) 320 { 321 struct msdosfsmount *pmp = dep->de_pmp; 322 u_long count; 323 int error; 324 325 /* 326 * The root of a DOS filesystem cannot be extended. 327 */ 328 if (dep->de_vnode != NULL && !FAT32(pmp)) 329 return EINVAL; 330 331 /* 332 * Directories cannot be extended. 333 */ 334 if (dep->de_Attributes & ATTR_DIRECTORY) 335 return EISDIR; 336 337 if (length <= dep->de_FileSize) 338 return E2BIG; 339 340 /* 341 * Compute the number of clusters to allocate. 342 */ 343 count = de_clcount(pmp, length) - de_clcount(pmp, dep->de_FileSize); 344 if (count > 0) { 345 if (count > pmp->pm_freeclustercount) 346 return (ENOSPC); 347 error = extendfile(dep, count, NULL, NULL, DE_CLEAR); 348 if (error) { 349 /* truncate the added clusters away again */ 350 (void) detrunc(dep, dep->de_FileSize, 0, cred); 351 return (error); 352 } 353 } 354 355 /* 356 * Zero extend file range; ubc_zerorange() uses ubc_alloc() and a 357 * memset(); we set the write size so ubc won't read in file data that 358 * is zero'd later. 359 */ 360 dep->de_FileSize = length; 361 dep->de_flag |= DE_UPDATE|DE_MODIFIED; 362 return 0; 363 } 364