1 /* $NetBSD: msdosfs_denode.c,v 1.7 2015/03/29 05:52:59 agc Exp $ */
4 * SPDX-License-Identifier: BSD-4-Clause
6 * Copyright (C) 1994, 1995, 1997 Wolfgang Solfrank.
7 * Copyright (C) 1994, 1995, 1997 TooLs GmbH.
9 * Original code by Paul Popelka (paulp@uts.amdahl.com) (see below).
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
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.
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.
37 * Written by Paul Popelka (paulp@uts.amdahl.com)
39 * You can do anything you want with this software, just don't say you wrote
40 * it, and don't remove this notice.
42 * This software is provided "as is".
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.
52 #include <sys/cdefs.h>
53 #include <sys/param.h>
54 #include <sys/errno.h>
62 #include <fs/msdosfs/bpb.h>
63 #include "msdos/denode.h"
64 #include <fs/msdosfs/fat.h>
65 #include <fs/msdosfs/msdosfsmount.h>
72 * If deget() succeeds it returns with the gotten denode locked().
74 * pmp - address of msdosfsmount structure of the filesystem containing
75 * the denode of interest. The pm_dev field and the address of
76 * the msdosfsmount structure are used.
77 * dirclust - which cluster bp contains, if dirclust is 0 (root directory)
78 * diroffset is relative to the beginning of the root directory,
79 * otherwise it is cluster relative.
80 * diroffset - offset past begin of cluster of denode we want
81 * depp - returns the address of the gotten denode.
84 deget(struct msdosfsmount *pmp, u_long dirclust, u_long diroffset,
85 int lkflags __unused, struct denode **depp)
89 struct direntry *direntptr;
93 MSDOSFS_DPRINTF(("deget(pmp %p, dirclust %lu, diroffset %lx, depp %p)\n",
94 pmp, dirclust, diroffset, depp));
97 * On FAT32 filesystems, root is a (more or less) normal
100 if (FAT32(pmp) && dirclust == MSDOSFSROOT)
101 dirclust = pmp->pm_rootdirblk;
103 inode = (uint64_t)pmp->pm_bpcluster * dirclust + diroffset;
105 ldep = ecalloc(1, sizeof(*ldep));
106 ldep->de_vnode = NULL;
108 ldep->de_dirclust = dirclust;
109 ldep->de_diroffset = diroffset;
110 ldep->de_inode = inode;
113 fc_purge(ldep, 0); /* init the FAT cache for this denode */
115 * Copy the directory entry into the denode area of the vnode.
117 if ((dirclust == MSDOSFSROOT
118 || (FAT32(pmp) && dirclust == pmp->pm_rootdirblk))
119 && diroffset == MSDOSFSROOT_OFS) {
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.
127 ldep->de_vnode = (struct vnode *)-1;
129 ldep->de_Attributes = ATTR_DIRECTORY;
130 ldep->de_LowerCase = 0;
132 ldep->de_StartCluster = pmp->pm_rootdirblk;
133 /* de_FileSize will be filled in further down */
135 ldep->de_StartCluster = MSDOSFSROOT;
136 ldep->de_FileSize = pmp->pm_rootdirsize * DEV_BSIZE;
139 * fill in time and date so that dos2unixtime() doesn't
140 * spit up when called from msdosfs_getattr() with root
144 ldep->de_CTime = 0x0000; /* 00:00:00 */
145 ldep->de_CDate = (0 << DD_YEAR_SHIFT) | (1 << DD_MONTH_SHIFT)
146 | (1 << DD_DAY_SHIFT);
148 ldep->de_ADate = ldep->de_CDate;
149 ldep->de_MTime = ldep->de_CTime;
150 ldep->de_MDate = ldep->de_CDate;
151 /* leave the other fields as garbage */
153 error = m_readep(pmp, dirclust, diroffset, &bp, &direntptr);
155 ldep->de_Name[0] = SLOT_DELETED;
160 (void)DE_INTERNALIZE(ldep, direntptr);
165 * Fill in a few fields of the vnode and finish filling in the
166 * denode. Then return the address of the found denode.
168 if (ldep->de_Attributes & ATTR_DIRECTORY) {
170 * Since DOS directory entries that describe directories
171 * have 0 in the filesize field, we take this opportunity
172 * to find out the length of the directory and plug it into
173 * the denode structure.
178 * XXX it sometimes happens that the "." entry has cluster
179 * number 0 when it shouldn't. Use the actual cluster number
180 * instead of what is written in directory entry.
182 if (diroffset == 0 && ldep->de_StartCluster != dirclust) {
183 MSDOSFS_DPRINTF(("deget(): \".\" entry at clust %lu != %lu\n",
184 dirclust, ldep->de_StartCluster));
186 ldep->de_StartCluster = dirclust;
189 if (ldep->de_StartCluster != MSDOSFSROOT) {
190 error = pcbmap(ldep, 0xffff, 0, &size, 0);
191 if (error == E2BIG) {
192 ldep->de_FileSize = de_cn2off(pmp, size);
195 MSDOSFS_DPRINTF(("deget(): pcbmap returned %d\n",
205 * Truncate the file described by dep to the length specified by length.
208 detrunc(struct denode *dep, u_long length, int flags, struct ucred *cred)
215 int isadir = dep->de_Attributes & ATTR_DIRECTORY;
217 struct msdosfsmount *pmp = dep->de_pmp;
219 MSDOSFS_DPRINTF(("detrunc(): file %s, length %lu, flags %x\n",
220 dep->de_Name, length, flags));
223 * Disallow attempts to truncate the root directory since it is of
224 * fixed size. That's just the way dos filesystems are. We use
225 * the VROOT bit in the vnode because checking for the directory
226 * bit and a startcluster of 0 in the denode is not adequate to
227 * recognize the root directory at this point in a file or
230 if (dep->de_vnode != NULL && !FAT32(pmp)) {
231 MSDOSFS_DPRINTF(("detrunc(): can't truncate root directory, "
232 "clust %ld, offset %ld\n",
233 dep->de_dirclust, dep->de_diroffset));
238 if (dep->de_FileSize < length)
239 return deextend(dep, length, cred);
242 * If the desired length is 0 then remember the starting cluster of
243 * the file and set the StartCluster field in the directory entry
244 * to 0. If the desired length is not zero, then get the number of
245 * the last cluster in the shortened file. Then get the number of
246 * the first cluster in the part of the file that is to be freed.
247 * Then set the next cluster pointer in the last cluster of the
248 * file to CLUST_EOFE.
251 chaintofree = dep->de_StartCluster;
252 dep->de_StartCluster = 0;
255 error = pcbmap(dep, de_clcount(pmp, length) - 1, 0,
258 MSDOSFS_DPRINTF(("detrunc(): pcbmap fails %d\n",
264 fc_purge(dep, de_clcount(pmp, length));
267 * If the new length is not a multiple of the cluster size then we
268 * must zero the tail end of the new last cluster in case it
269 * becomes part of the file again because of a seek.
271 if ((boff = length & pmp->pm_crbomask) != 0) {
273 bn = cntobn(pmp, eofentry);
274 error = bread((void *)pmp->pm_devvp, bn,
275 pmp->pm_bpcluster, 0, &bp);
278 MSDOSFS_DPRINTF(("detrunc(): bread fails %d\n",
283 memset(bp->b_data + boff, 0, pmp->pm_bpcluster - boff);
289 * Write out the updated directory entry. Even if the update fails
290 * we free the trailing clusters.
292 dep->de_FileSize = length;
294 dep->de_flag |= DE_UPDATE|DE_MODIFIED;
295 MSDOSFS_DPRINTF(("detrunc(): eofentry %lu\n", eofentry));
298 * If we need to break the cluster chain for the file then do it
301 if (eofentry != ~0ul) {
302 error = fatentry(FAT_GET_AND_SET, pmp, eofentry,
303 &chaintofree, CLUST_EOFE);
305 MSDOSFS_DPRINTF(("detrunc(): fatentry errors %d\n",
309 fc_setcache(dep, FC_LASTFC, de_cluster(pmp, length - 1),
314 * Now free the clusters removed from the file because of the
317 if (chaintofree != 0 && !MSDOSFSEOF(pmp, chaintofree))
318 freeclusterchain(pmp, chaintofree);
324 * Extend the file described by dep to length specified by length.
327 deextend(struct denode *dep, u_long length, struct ucred *cred)
329 struct msdosfsmount *pmp = dep->de_pmp;
334 * The root of a DOS filesystem cannot be extended.
336 if (dep->de_vnode != NULL && !FAT32(pmp))
340 * Directories cannot be extended.
342 if (dep->de_Attributes & ATTR_DIRECTORY)
345 if (length <= dep->de_FileSize)
349 * Compute the number of clusters to allocate.
351 count = de_clcount(pmp, length) - de_clcount(pmp, dep->de_FileSize);
353 if (count > pmp->pm_freeclustercount)
355 error = m_extendfile(dep, count, NULL, NULL, DE_CLEAR);
357 /* truncate the added clusters away again */
358 (void) detrunc(dep, dep->de_FileSize, 0, cred);
364 * Zero extend file range; ubc_zerorange() uses ubc_alloc() and a
365 * memset(); we set the write size so ubc won't read in file data that
368 dep->de_FileSize = length;
369 dep->de_flag |= DE_UPDATE | DE_MODIFIED;