usr.sbin/makefs/msdos/msdosfs_denode.c

   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 __KERNEL_RCSID(0, "$NetBSD: msdosfs_denode.c,v 1.7 2015/03/29 05:52:59 agc Exp $");
  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 }