1 /* $NetBSD: msdosfs_vnops.c,v 1.19 2017/04/13 17:10:12 christos 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 __FBSDID("$FreeBSD$");
55 #include <sys/param.h>
56 #include <sys/clock.h>
57 #include <sys/errno.h>
68 #include <fs/msdosfs/bpb.h>
69 #include "msdos/direntry.h"
70 #include <fs/msdosfs/denode.h>
71 #include <fs/msdosfs/fat.h>
72 #include <fs/msdosfs/msdosfsmount.h>
80 * In the ufs filesystem the inodes, superblocks, and indirect blocks are
81 * read/written using the vnode for the filesystem. Blocks that represent
82 * the contents of a file are read/written using the vnode for the file
83 * (including directories when they are read/written as files). This
84 * presents problems for the dos filesystem because data that should be in
85 * an inode (if dos had them) resides in the directory itself. Since we
86 * must update directory entries without the benefit of having the vnode
87 * for the directory we must use the vnode for the filesystem. This means
88 * that when a directory is actually read/written (via read, write, or
89 * readdir, or seek) we must use the vnode for the filesystem instead of
90 * the vnode for the directory as would happen in ufs. This is to insure we
91 * retrieve the correct block from the buffer cache since the hash value is
92 * based upon the vnode address and the desired block number.
95 static int msdosfs_wfile(const char *, struct denode *, fsnode *);
96 static void unix2fattime(const struct timespec *tsp, uint16_t *ddp,
100 msdosfs_times(struct denode *dep, const struct stat *st)
105 unix2fattime(&st->st_birthtim, &dep->de_CDate, &dep->de_CTime);
106 unix2fattime(&st->st_atim, &dep->de_ADate, NULL);
107 unix2fattime(&st->st_mtim, &dep->de_MDate, &dep->de_MTime);
111 unix2fattime(const struct timespec *tsp, uint16_t *ddp, uint16_t *dtp)
117 localtime_r(&t1, <);
119 unsigned long fat_time = ((lt.tm_year - 80) << 25) |
120 ((lt.tm_mon + 1) << 21) |
127 *ddp = (uint16_t)(fat_time >> 16);
129 *dtp = (uint16_t)fat_time;
133 * When we search a directory the blocks containing directory entries are
134 * read and examined. The directory entries contain information that would
135 * normally be in the inode of a unix filesystem. This means that some of
136 * a directory's contents may also be in memory resident denodes (sort of
137 * an inode). This can cause problems if we are searching while some other
138 * process is modifying a directory. To prevent one process from accessing
139 * incompletely modified directory information we depend upon being the
140 * sole owner of a directory block. bread/brelse provide this service.
141 * This being the case, when a process modifies a directory it must first
142 * acquire the disk block that contains the directory entry to be modified.
143 * Then update the disk block and the denode, and then write the disk block
144 * out to disk. This way disk blocks containing directory entries and in
145 * memory denode's will be in synch.
148 msdosfs_findslot(struct denode *dp, struct componentname *cnp)
159 struct msdosfsmount *pmp;
161 struct direntry *dep;
162 u_char dosfilename[12];
164 int chksum = -1, chksum_ok;
169 switch (unix2dosfn((const u_char *)cnp->cn_nameptr, dosfilename,
170 cnp->cn_namelen, 0)) {
176 wincnt = winSlotCnt((const u_char *)cnp->cn_nameptr,
177 cnp->cn_namelen) + 1;
181 wincnt = winSlotCnt((const u_char *)cnp->cn_nameptr,
182 cnp->cn_namelen) + 1;
186 if (pmp->pm_flags & MSDOSFSMNT_SHORTNAME)
190 * Suppress search for slots unless creating
191 * file and at end of pathname, in which case
192 * we watch for a place to put the new file in
193 * case it doesn't already exist.
196 MSDOSFS_DPRINTF(("%s(): dos filename: %s\n", __func__, dosfilename));
198 * Search the directory pointed at by vdp for the name pointed at
199 * by cnp->cn_nameptr.
202 * The outer loop ranges over the clusters that make up the
203 * directory. Note that the root directory is different from all
204 * other directories. It has a fixed number of blocks that are not
205 * part of the pool of allocatable clusters. So, we treat it a
206 * little differently. The root directory starts at "cluster" 0.
209 for (frcn = 0; diroff < dp->de_FileSize; frcn++) {
210 if ((error = pcbmap(dp, frcn, &bn, &cluster, &blsize)) != 0) {
215 error = bread(pmp->pm_devvp, bn, blsize, 0, &bp);
219 for (blkoff = 0; blkoff < blsize;
220 blkoff += sizeof(struct direntry),
221 diroff += sizeof(struct direntry)) {
222 dep = (struct direntry *)(bp->b_data + blkoff);
224 * If the slot is empty and we are still looking
225 * for an empty then remember this one. If the
226 * slot is not empty then check to see if it
227 * matches what we are looking for. If the slot
228 * has never been filled with anything, then the
229 * remainder of the directory has never been used,
230 * so there is no point in searching it.
232 if (dep->deName[0] == SLOT_EMPTY ||
233 dep->deName[0] == SLOT_DELETED) {
235 * Drop memory of previous long matches
239 if (slotcount < wincnt) {
243 if (dep->deName[0] == SLOT_EMPTY) {
249 * If there wasn't enough space for our
250 * winentries, forget about the empty space
252 if (slotcount < wincnt)
256 * Check for Win95 long filename entry
258 if (dep->deAttributes == ATTR_WIN95) {
259 if (pmp->pm_flags & MSDOSFSMNT_SHORTNAME)
263 (const u_char *)cnp->cn_nameptr,
265 (struct winentry *)dep, chksum);
270 * Ignore volume labels (anywhere, not just
271 * the root directory).
273 if (dep->deAttributes & ATTR_VOLUME) {
279 * Check for a checksum or name match
281 chksum_ok = (chksum == winChksum(dep->deName));
283 && (!olddos || memcmp(dosfilename, dep->deName, 11))) {
287 MSDOSFS_DPRINTF(("%s(): match blkoff %d, diroff %u\n",
288 __func__, blkoff, diroff));
290 * Remember where this directory
291 * entry came from for whoever did
294 dp->de_fndoffset = diroff;
299 } /* for (blkoff = 0; .... */
301 * Release the buffer holding the directory cluster just
305 } /* for (frcn = 0; ; frcn++) */
309 * We hold no disk buffers at this point.
313 * If we get here we didn't find the entry we were looking for. But
314 * that's ok if we are creating or renaming and are at the end of
315 * the pathname and the directory hasn't been removed.
317 MSDOSFS_DPRINTF(("%s(): refcnt %ld, slotcount %d, slotoffset %d\n",
318 __func__, dp->de_refcnt, slotcount, slotoffset));
320 * Fixup the slot description to point to the place where
321 * we might put the new DOS direntry (putting the Win95
322 * long name entries before that)
328 if (wincnt > slotcount) {
329 slotoffset += sizeof(struct direntry) * (wincnt - slotcount);
333 * Return an indication of where the new directory
334 * entry should be put.
336 dp->de_fndoffset = slotoffset;
337 dp->de_fndcnt = wincnt - 1;
340 * We return with the directory locked, so that
341 * the parameters we set up above will still be
342 * valid if we actually decide to do a direnter().
343 * We return ni_vp == NULL to indicate that the entry
344 * does not currently exist; we leave a pointer to
345 * the (locked) directory inode in ndp->ni_dvp.
347 * NB - if the directory is unlocked, then this
348 * information cannot be used.
354 * Create a regular file. On entry the directory to contain the file being
355 * created is locked. We must release before we return.
358 msdosfs_mkfile(const char *path, struct denode *pdep, fsnode *node)
360 struct componentname cn;
361 struct denode ndirent;
364 struct stat *st = &node->inode->st;
366 cn.cn_nameptr = node->name;
367 cn.cn_namelen = strlen(node->name);
369 MSDOSFS_DPRINTF(("%s(name %s, mode 0%o size %zu)\n",
370 __func__, node->name, st->st_mode, (size_t)st->st_size));
373 * If this is the root directory and there is no space left we
374 * can't do anything. This is because the root directory can not
377 if (pdep->de_StartCluster == MSDOSFSROOT
378 && pdep->de_fndoffset >= pdep->de_FileSize) {
384 * Create a directory entry for the file, then call createde() to
385 * have it installed. NOTE: DOS files are always executable. We
386 * use the absence of the owner write bit to make the file
389 memset(&ndirent, 0, sizeof(ndirent));
390 if ((error = uniqdosname(pdep, &cn, ndirent.de_Name)) != 0)
393 ndirent.de_Attributes = (st->st_mode & S_IWUSR) ?
394 ATTR_ARCHIVE : ATTR_ARCHIVE | ATTR_READONLY;
395 ndirent.de_StartCluster = 0;
396 ndirent.de_FileSize = 0;
397 ndirent.de_pmp = pdep->de_pmp;
398 ndirent.de_flag = DE_ACCESS | DE_CREATE | DE_UPDATE;
399 msdosfs_times(&ndirent, &node->inode->st);
401 if ((error = msdosfs_findslot(pdep, &cn)) != 0)
403 if ((error = createde(&ndirent, pdep, &dep, &cn)) != 0)
405 if ((error = msdosfs_wfile(path, dep, node)) != 0)
414 msdosfs_updatede(struct denode *dep)
417 struct direntry *dirp;
420 dep->de_flag &= ~DE_MODIFIED;
421 error = readde(dep, &bp, &dirp);
424 DE_EXTERNALIZE(dirp, dep);
430 * Write data to a file or directory.
433 msdosfs_wfile(const char *path, struct denode *dep, fsnode *node)
436 size_t osize = dep->de_FileSize;
437 struct stat *st = &node->inode->st;
439 struct msdosfsmount *pmp = dep->de_pmp;
444 error = 0; /* XXX: gcc/vax */
445 MSDOSFS_DPRINTF(("%s(diroff %lu, dirclust %lu, startcluster %lu)\n",
446 __func__, dep->de_diroffset, dep->de_dirclust,
447 dep->de_StartCluster));
448 if (st->st_size == 0)
451 /* Don't bother to try to write files larger than the fs limit */
452 if (st->st_size > MSDOSFS_FILESIZE_MAX)
456 MSDOSFS_DPRINTF(("%s(nsize=%zu, osize=%zu)\n", __func__, nsize, osize));
458 if ((error = deextend(dep, nsize, NULL)) != 0)
460 if ((error = msdosfs_updatede(dep)) != 0)
464 if ((fd = open(path, O_RDONLY)) == -1) {
466 MSDOSFS_DPRINTF(("open %s: %s", path, strerror(error)));
470 if ((dat = mmap(0, nsize, PROT_READ, MAP_FILE | MAP_PRIVATE, fd, 0))
473 MSDOSFS_DPRINTF(("%s: mmap %s: %s", __func__, node->name,
480 for (offs = 0; offs < nsize;) {
483 u_long on = offs & pmp->pm_crbomask;
485 if ((error = pcbmap(dep, cn++, &bn, NULL, &blsize)) != 0) {
486 MSDOSFS_DPRINTF(("%s: pcbmap %lu",
487 __func__, (unsigned long)bn));
491 MSDOSFS_DPRINTF(("%s(cn=%lu, bn=%llu, blsize=%d)\n",
492 __func__, cn, (unsigned long long)bn, blsize));
493 if ((error = bread(pmp->pm_devvp, bn, blsize, 0, &bp)) != 0) {
494 MSDOSFS_DPRINTF(("bread %d\n", error));
497 cpsize = MIN((nsize - offs), blsize - on);
498 memcpy(bp->b_data + on, dat + offs, cpsize);
510 static const struct {
512 struct direntry dotdot;
514 { ". ", /* the . entry */
515 ATTR_DIRECTORY, /* file attribute */
517 0, { 0, 0 }, { 0, 0 }, /* create time & date */
518 { 0, 0 }, /* access date */
519 { 0, 0 }, /* high bits of start cluster */
520 { 210, 4 }, { 210, 4 }, /* modify time & date */
521 { 0, 0 }, /* startcluster */
522 { 0, 0, 0, 0 } /* filesize */
524 { ".. ", /* the .. entry */
525 ATTR_DIRECTORY, /* file attribute */
527 0, { 0, 0 }, { 0, 0 }, /* create time & date */
528 { 0, 0 }, /* access date */
529 { 0, 0 }, /* high bits of start cluster */
530 { 210, 4 }, { 210, 4 }, /* modify time & date */
531 { 0, 0 }, /* startcluster */
532 { 0, 0, 0, 0 } /* filesize */
537 msdosfs_mkdire(const char *path, struct denode *pdep, fsnode *node) {
538 struct denode ndirent;
540 struct componentname cn;
541 struct msdosfsmount *pmp = pdep->de_pmp;
543 u_long newcluster, pcl, bn;
544 struct direntry *denp;
547 cn.cn_nameptr = node->name;
548 cn.cn_namelen = strlen(node->name);
550 * If this is the root directory and there is no space left we
551 * can't do anything. This is because the root directory can not
554 if (pdep->de_StartCluster == MSDOSFSROOT
555 && pdep->de_fndoffset >= pdep->de_FileSize) {
561 * Allocate a cluster to hold the about to be created directory.
563 error = clusteralloc(pmp, 0, 1, CLUST_EOFE, &newcluster, NULL);
567 memset(&ndirent, 0, sizeof(ndirent));
568 ndirent.de_pmp = pmp;
569 ndirent.de_flag = DE_ACCESS | DE_CREATE | DE_UPDATE;
570 msdosfs_times(&ndirent, &node->inode->st);
573 * Now fill the cluster with the "." and ".." entries. And write
574 * the cluster to disk. This way it is there for the parent
575 * directory to be pointing at if there were a crash.
577 bn = cntobn(pmp, newcluster);
578 MSDOSFS_DPRINTF(("%s(newcluster %lu, bn=%lu)\n",
579 __func__, newcluster, bn));
580 /* always succeeds */
581 bp = getblk(pmp->pm_devvp, bn, pmp->pm_bpcluster, 0, 0, 0);
582 memset(bp->b_data, 0, pmp->pm_bpcluster);
583 memcpy(bp->b_data, &dosdirtemplate, sizeof dosdirtemplate);
584 denp = (struct direntry *)bp->b_data;
585 putushort(denp[0].deStartCluster, newcluster);
586 putushort(denp[0].deCDate, ndirent.de_CDate);
587 putushort(denp[0].deCTime, ndirent.de_CTime);
588 denp[0].deCHundredth = ndirent.de_CHun;
589 putushort(denp[0].deADate, ndirent.de_ADate);
590 putushort(denp[0].deMDate, ndirent.de_MDate);
591 putushort(denp[0].deMTime, ndirent.de_MTime);
592 pcl = pdep->de_StartCluster;
593 MSDOSFS_DPRINTF(("%s(pcl %lu, rootdirblk=%lu)\n", __func__, pcl,
594 pmp->pm_rootdirblk));
595 if (FAT32(pmp) && pcl == pmp->pm_rootdirblk)
597 putushort(denp[1].deStartCluster, pcl);
598 putushort(denp[1].deCDate, ndirent.de_CDate);
599 putushort(denp[1].deCTime, ndirent.de_CTime);
600 denp[1].deCHundredth = ndirent.de_CHun;
601 putushort(denp[1].deADate, ndirent.de_ADate);
602 putushort(denp[1].deMDate, ndirent.de_MDate);
603 putushort(denp[1].deMTime, ndirent.de_MTime);
605 putushort(denp[0].deHighClust, newcluster >> 16);
606 putushort(denp[1].deHighClust, pdep->de_StartCluster >> 16);
608 putushort(denp[0].deHighClust, 0);
609 putushort(denp[1].deHighClust, 0);
612 if ((error = bwrite(bp)) != 0)
616 * Now build up a directory entry pointing to the newly allocated
617 * cluster. This will be written to an empty slot in the parent
620 if ((error = uniqdosname(pdep, &cn, ndirent.de_Name)) != 0)
623 ndirent.de_Attributes = ATTR_DIRECTORY;
624 ndirent.de_StartCluster = newcluster;
625 ndirent.de_FileSize = 0;
626 ndirent.de_pmp = pdep->de_pmp;
627 if ((error = msdosfs_findslot(pdep, &cn)) != 0)
629 if ((error = createde(&ndirent, pdep, &dep, &cn)) != 0)
631 if ((error = msdosfs_updatede(dep)) != 0)
636 clusterfree(pmp, newcluster, NULL);