1 /* $NetBSD: msdosfs_denode.c,v 1.7 2015/03/29 05:52:59 agc Exp $ */
4 * Copyright (C) 1994, 1995, 1997 Wolfgang Solfrank.
5 * Copyright (C) 1994, 1995, 1997 TooLs GmbH.
7 * Original code by Paul Popelka (paulp@uts.amdahl.com) (see below).
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
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.
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.
35 * Written by Paul Popelka (paulp@uts.amdahl.com)
37 * You can do anything you want with this software, just don't say you wrote
38 * it, and don't remove this notice.
40 * This software is provided "as is".
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.
50 #if HAVE_NBTOOL_CONFIG_H
51 #include "nbtool_config.h"
54 #include <sys/cdefs.h>
55 __FBSDID("$FreeBSD$");
57 #include <sys/param.h>
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>
70 * If deget() succeeds it returns with the gotten denode locked().
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.
82 deget(struct msdosfsmount *pmp, u_long dirclust, u_long diroffset,
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 */
90 struct direntry *direntptr;
95 printf("deget(pmp %p, dirclust %lu, diroffset %lx, depp %p)\n",
96 pmp, dirclust, diroffset, depp);
100 * On FAT32 filesystems, root is a (more or less) normal
103 if (FAT32(pmp) && dirclust == MSDOSFSROOT)
104 dirclust = pmp->pm_rootdirblk;
106 ldep = ecalloc(1, sizeof(*ldep));
107 ldep->de_vnode = NULL;
111 ldep->de_dev = pmp->pm_dev;
112 ldep->de_dirclust = dirclust;
113 ldep->de_diroffset = diroffset;
115 ldep->de_devvp = pmp->pm_devvp;
119 * Copy the directory entry into the denode area of the vnode.
121 if ((dirclust == MSDOSFSROOT
122 || (FAT32(pmp) && dirclust == pmp->pm_rootdirblk))
123 && diroffset == MSDOSFSROOT_OFS) {
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.
131 ldep->de_vnode = (struct vnode *)-1;
133 ldep->de_Attributes = ATTR_DIRECTORY;
135 ldep->de_StartCluster = pmp->pm_rootdirblk;
136 /* de_FileSize will be filled in further down */
138 ldep->de_StartCluster = MSDOSFSROOT;
139 ldep->de_FileSize = pmp->pm_rootdirsize * pmp->pm_BytesPerSec;
142 * fill in time and date so that dos2unixtime() doesn't
143 * spit up when called from msdosfs_getattr() with root
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);
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 */
156 error = readep(pmp, dirclust, diroffset, &bp, &direntptr);
158 ldep->de_devvp = NULL;
159 ldep->de_Name[0] = SLOT_DELETED;
162 DE_INTERNALIZE(ldep, direntptr);
167 * Fill in a few fields of the vnode and finish filling in the
168 * denode. Then return the address of the found denode.
170 if (ldep->de_Attributes & ATTR_DIRECTORY) {
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.
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);
185 printf("deget(): pcbmap returned %d\n", error);
193 * Truncate the file described by dep to the length specified by length.
196 detrunc(struct denode *dep, u_long length, int flags, struct kauth_cred *cred)
201 u_long chaintofree = 0;
202 daddr_t bn, lastblock;
204 int isadir = dep->de_Attributes & ATTR_DIRECTORY;
206 struct msdosfsmount *pmp = dep->de_pmp;
209 printf("detrunc(): file %s, length %lu, flags %x\n", dep->de_Name, length, flags);
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
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);
226 if (dep->de_FileSize < length)
227 return (deextend(dep, length, cred));
228 lastblock = de_clcount(pmp, length) - 1;
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.
240 chaintofree = dep->de_StartCluster;
241 dep->de_StartCluster = 0;
244 error = pcbmap(dep, lastblock, 0, &eofentry, 0);
247 printf("detrunc(): pcbmap fails %d\n", error);
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.
258 if ((boff = length & pmp->pm_crbomask) != 0) {
260 bn = cntobn(pmp, eofentry);
261 error = bread(pmp->pm_devvp, de_bn2kb(pmp, bn),
262 pmp->pm_bpcluster, B_MODIFY, &bp);
265 printf("detrunc(): bread fails %d\n", error);
269 memset((char *)bp->b_data + boff, 0,
270 pmp->pm_bpcluster - boff);
279 * Write out the updated directory entry. Even if the update fails
280 * we free the trailing clusters.
282 dep->de_FileSize = length;
284 dep->de_flag |= DE_UPDATE|DE_MODIFIED;
286 printf("detrunc(): allerror %d, eofentry %lu\n",
291 * If we need to break the cluster chain for the file then do it
294 if (eofentry != (u_long)~0) {
295 error = fatentry(FAT_GET_AND_SET, pmp, eofentry,
296 &chaintofree, CLUST_EOFE);
299 printf("detrunc(): fatentry errors %d\n", error);
306 * Now free the clusters removed from the file because of the
309 if (chaintofree != 0 && !MSDOSFSEOF(chaintofree, pmp->pm_fatmask))
310 freeclusterchain(pmp, chaintofree);
316 * Extend the file described by dep to length specified by length.
319 deextend(struct denode *dep, u_long length, struct kauth_cred *cred)
321 struct msdosfsmount *pmp = dep->de_pmp;
326 * The root of a DOS filesystem cannot be extended.
328 if (dep->de_vnode != NULL && !FAT32(pmp))
332 * Directories cannot be extended.
334 if (dep->de_Attributes & ATTR_DIRECTORY)
337 if (length <= dep->de_FileSize)
341 * Compute the number of clusters to allocate.
343 count = de_clcount(pmp, length) - de_clcount(pmp, dep->de_FileSize);
345 if (count > pmp->pm_freeclustercount)
347 error = extendfile(dep, count, NULL, NULL, DE_CLEAR);
349 /* truncate the added clusters away again */
350 (void) detrunc(dep, dep->de_FileSize, 0, cred);
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
360 dep->de_FileSize = length;
361 dep->de_flag |= DE_UPDATE|DE_MODIFIED;