1/*	$NetBSD: msdosfs_denode.c,v 1.7 2015/03/29 05:52:59 agc Exp $	*/
2
3/*-
4 * SPDX-License-Identifier: BSD-4-Clause
5 *
6 * Copyright (C) 1994, 1995, 1997 Wolfgang Solfrank.
7 * Copyright (C) 1994, 1995, 1997 TooLs GmbH.
8 * All rights reserved.
9 * Original code by Paul Popelka (paulp@uts.amdahl.com) (see below).
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
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.
24 *
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.
35 */
36/*-
37 * Written by Paul Popelka (paulp@uts.amdahl.com)
38 *
39 * You can do anything you want with this software, just don't say you wrote
40 * it, and don't remove this notice.
41 *
42 * This software is provided "as is".
43 *
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.
48 *
49 * October 1992
50 */
51
52#include <sys/cdefs.h>
53__FBSDID("$FreeBSD$");
54
55#include <sys/param.h>
56#include <sys/errno.h>
57#include <sys/vnode.h>
58
59#include <stdio.h>
60#include <string.h>
61#include <stdlib.h>
62#include <util.h>
63
64#include <fs/msdosfs/bpb.h>
65
66#include "makefs.h"
67#include "msdos.h"
68
69#include "ffs/buf.h"
70
71#include "msdos/denode.h"
72#include "msdos/direntry.h"
73#include "msdos/fat.h"
74#include "msdos/msdosfsmount.h"
75
76/*
77 * If deget() succeeds it returns with the gotten denode locked().
78 *
79 * pmp	     - address of msdosfsmount structure of the filesystem containing
80 *	       the denode of interest.  The pm_dev field and the address of
81 *	       the msdosfsmount structure are used.
82 * dirclust  - which cluster bp contains, if dirclust is 0 (root directory)
83 *	       diroffset is relative to the beginning of the root directory,
84 *	       otherwise it is cluster relative.
85 * diroffset - offset past begin of cluster of denode we want
86 * depp	     - returns the address of the gotten denode.
87 */
88int
89deget(struct msdosfsmount *pmp, u_long dirclust, u_long diroffset,
90    struct denode **depp)
91{
92	int error;
93	uint64_t inode;
94	struct direntry *direntptr;
95	struct denode *ldep;
96	struct buf *bp;
97
98	MSDOSFS_DPRINTF(("deget(pmp %p, dirclust %lu, diroffset %lx, depp %p)\n",
99	    pmp, dirclust, diroffset, depp));
100
101	/*
102	 * On FAT32 filesystems, root is a (more or less) normal
103	 * directory
104	 */
105	if (FAT32(pmp) && dirclust == MSDOSFSROOT)
106		dirclust = pmp->pm_rootdirblk;
107
108	inode = (uint64_t)pmp->pm_bpcluster * dirclust + diroffset;
109
110	ldep = ecalloc(1, sizeof(*ldep));
111	ldep->de_vnode = NULL;
112	ldep->de_flag = 0;
113	ldep->de_dirclust = dirclust;
114	ldep->de_diroffset = diroffset;
115	ldep->de_inode = inode;
116	ldep->de_pmp = pmp;
117	ldep->de_refcnt = 1;
118	fc_purge(ldep, 0);	/* init the FAT cache for this denode */
119	/*
120	 * Copy the directory entry into the denode area of the vnode.
121	 */
122	if ((dirclust == MSDOSFSROOT
123	     || (FAT32(pmp) && dirclust == pmp->pm_rootdirblk))
124	    && diroffset == MSDOSFSROOT_OFS) {
125		/*
126		 * Directory entry for the root directory. There isn't one,
127		 * so we manufacture one. We should probably rummage
128		 * through the root directory and find a label entry (if it
129		 * exists), and then use the time and date from that entry
130		 * as the time and date for the root denode.
131		 */
132		ldep->de_vnode = (struct vnode *)-1;
133
134		ldep->de_Attributes = ATTR_DIRECTORY;
135		ldep->de_LowerCase = 0;
136		if (FAT32(pmp))
137			ldep->de_StartCluster = pmp->pm_rootdirblk;
138			/* de_FileSize will be filled in further down */
139		else {
140			ldep->de_StartCluster = MSDOSFSROOT;
141			ldep->de_FileSize = pmp->pm_rootdirsize * DEV_BSIZE;
142		}
143		/*
144		 * fill in time and date so that dos2unixtime() doesn't
145		 * spit up when called from msdosfs_getattr() with root
146		 * denode
147		 */
148		ldep->de_CHun = 0;
149		ldep->de_CTime = 0x0000;	/* 00:00:00	 */
150		ldep->de_CDate = (0 << DD_YEAR_SHIFT) | (1 << DD_MONTH_SHIFT)
151		    | (1 << DD_DAY_SHIFT);
152		/* Jan 1, 1980	 */
153		ldep->de_ADate = ldep->de_CDate;
154		ldep->de_MTime = ldep->de_CTime;
155		ldep->de_MDate = ldep->de_CDate;
156		/* leave the other fields as garbage */
157	} else {
158		error = readep(pmp, dirclust, diroffset, &bp, &direntptr);
159		if (error) {
160			ldep->de_Name[0] = SLOT_DELETED;
161
162			*depp = NULL;
163			return (error);
164		}
165		(void)DE_INTERNALIZE(ldep, direntptr);
166		brelse(bp);
167	}
168
169	/*
170	 * Fill in a few fields of the vnode and finish filling in the
171	 * denode.  Then return the address of the found denode.
172	 */
173	if (ldep->de_Attributes & ATTR_DIRECTORY) {
174		/*
175		 * Since DOS directory entries that describe directories
176		 * have 0 in the filesize field, we take this opportunity
177		 * to find out the length of the directory and plug it into
178		 * the denode structure.
179		 */
180		u_long size;
181
182		/*
183		 * XXX it sometimes happens that the "." entry has cluster
184		 * number 0 when it shouldn't.  Use the actual cluster number
185		 * instead of what is written in directory entry.
186		 */
187		if (diroffset == 0 && ldep->de_StartCluster != dirclust) {
188			MSDOSFS_DPRINTF(("deget(): \".\" entry at clust %lu != %lu\n",
189			    dirclust, ldep->de_StartCluster));
190
191			ldep->de_StartCluster = dirclust;
192		}
193
194		if (ldep->de_StartCluster != MSDOSFSROOT) {
195			error = pcbmap(ldep, 0xffff, 0, &size, 0);
196			if (error == E2BIG) {
197				ldep->de_FileSize = de_cn2off(pmp, size);
198				error = 0;
199			} else {
200				MSDOSFS_DPRINTF(("deget(): pcbmap returned %d\n",
201				    error));
202			}
203		}
204	}
205	*depp = ldep;
206	return (0);
207}
208
209/*
210 * Truncate the file described by dep to the length specified by length.
211 */
212int
213detrunc(struct denode *dep, u_long length, int flags)
214{
215	int error;
216	int allerror;
217	u_long eofentry;
218	u_long chaintofree;
219	daddr_t bn;
220	int boff;
221	int isadir = dep->de_Attributes & ATTR_DIRECTORY;
222	struct buf *bp;
223	struct msdosfsmount *pmp = dep->de_pmp;
224
225	MSDOSFS_DPRINTF(("detrunc(): file %s, length %lu, flags %x\n",
226	    dep->de_Name, length, flags));
227
228	/*
229	 * Disallow attempts to truncate the root directory since it is of
230	 * fixed size.  That's just the way dos filesystems are.  We use
231	 * the VROOT bit in the vnode because checking for the directory
232	 * bit and a startcluster of 0 in the denode is not adequate to
233	 * recognize the root directory at this point in a file or
234	 * directory's life.
235	 */
236	if (dep->de_vnode != NULL && !FAT32(pmp)) {
237		MSDOSFS_DPRINTF(("detrunc(): can't truncate root directory, "
238		    "clust %ld, offset %ld\n",
239		    dep->de_dirclust, dep->de_diroffset));
240
241		return (EINVAL);
242	}
243
244	if (dep->de_FileSize < length)
245		return deextend(dep, length);
246
247	/*
248	 * If the desired length is 0 then remember the starting cluster of
249	 * the file and set the StartCluster field in the directory entry
250	 * to 0.  If the desired length is not zero, then get the number of
251	 * the last cluster in the shortened file.  Then get the number of
252	 * the first cluster in the part of the file that is to be freed.
253	 * Then set the next cluster pointer in the last cluster of the
254	 * file to CLUST_EOFE.
255	 */
256	if (length == 0) {
257		chaintofree = dep->de_StartCluster;
258		dep->de_StartCluster = 0;
259		eofentry = ~0;
260	} else {
261		error = pcbmap(dep, de_clcount(pmp, length) - 1, 0,
262		    &eofentry, 0);
263		if (error) {
264			MSDOSFS_DPRINTF(("detrunc(): pcbmap fails %d\n",
265			    error));
266			return (error);
267		}
268	}
269
270	fc_purge(dep, de_clcount(pmp, length));
271
272	/*
273	 * If the new length is not a multiple of the cluster size then we
274	 * must zero the tail end of the new last cluster in case it
275	 * becomes part of the file again because of a seek.
276	 */
277	if ((boff = length & pmp->pm_crbomask) != 0) {
278		if (isadir) {
279			bn = cntobn(pmp, eofentry);
280			error = bread(pmp->pm_devvp, bn, pmp->pm_bpcluster,
281			    0, &bp);
282			if (error) {
283				brelse(bp);
284				MSDOSFS_DPRINTF(("detrunc(): bread fails %d\n",
285				    error));
286
287				return (error);
288			}
289			memset(bp->b_data + boff, 0, pmp->pm_bpcluster - boff);
290			if (flags & IO_SYNC)
291				bwrite(bp);
292			else
293				bdwrite(bp);
294		}
295	}
296
297	/*
298	 * Write out the updated directory entry.  Even if the update fails
299	 * we free the trailing clusters.
300	 */
301	dep->de_FileSize = length;
302	if (!isadir)
303		dep->de_flag |= DE_UPDATE|DE_MODIFIED;
304	MSDOSFS_DPRINTF(("detrunc(): allerror %d, eofentry %lu\n",
305	    allerror, eofentry));
306
307	/*
308	 * If we need to break the cluster chain for the file then do it
309	 * now.
310	 */
311	if (eofentry != ~0) {
312		error = fatentry(FAT_GET_AND_SET, pmp, eofentry,
313				 &chaintofree, CLUST_EOFE);
314		if (error) {
315			MSDOSFS_DPRINTF(("detrunc(): fatentry errors %d\n",
316			    error));
317			return (error);
318		}
319		fc_setcache(dep, FC_LASTFC, de_cluster(pmp, length - 1),
320		    eofentry);
321	}
322
323	/*
324	 * Now free the clusters removed from the file because of the
325	 * truncation.
326	 */
327	if (chaintofree != 0 && !MSDOSFSEOF(pmp, chaintofree))
328		freeclusterchain(pmp, chaintofree);
329
330	return (allerror);
331}
332
333/*
334 * Extend the file described by dep to length specified by length.
335 */
336int
337deextend(struct denode *dep, u_long length)
338{
339	struct msdosfsmount *pmp = dep->de_pmp;
340	u_long count;
341	int error;
342
343	/*
344	 * The root of a DOS filesystem cannot be extended.
345	 */
346	if (dep->de_vnode != NULL && !FAT32(pmp))
347		return (EINVAL);
348
349	/*
350	 * Directories cannot be extended.
351	 */
352	if (dep->de_Attributes & ATTR_DIRECTORY)
353		return (EISDIR);
354
355	if (length <= dep->de_FileSize)
356		return (E2BIG);
357
358	/*
359	 * Compute the number of clusters to allocate.
360	 */
361	count = de_clcount(pmp, length) - de_clcount(pmp, dep->de_FileSize);
362	if (count > 0) {
363		if (count > pmp->pm_freeclustercount)
364			return (ENOSPC);
365		error = extendfile(dep, count, NULL, NULL, DE_CLEAR);
366		if (error) {
367			/* truncate the added clusters away again */
368			(void) detrunc(dep, dep->de_FileSize, 0);
369			return (error);
370		}
371	}
372
373	/*
374	 * Zero extend file range; ubc_zerorange() uses ubc_alloc() and a
375	 * memset(); we set the write size so ubc won't read in file data that
376	 * is zero'd later.
377	 */
378	dep->de_FileSize = length;
379	dep->de_flag |= DE_UPDATE | DE_MODIFIED;
380	return 0;
381}
382