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>
69 #include <fs/msdosfs/bpb.h>
70 #include "msdos/direntry.h"
71 #include <fs/msdosfs/denode.h>
72 #include <fs/msdosfs/fat.h>
73 #include <fs/msdosfs/msdosfsmount.h>
81 * In the ufs filesystem the inodes, superblocks, and indirect blocks are
82 * read/written using the vnode for the filesystem. Blocks that represent
83 * the contents of a file are read/written using the vnode for the file
84 * (including directories when they are read/written as files). This
85 * presents problems for the dos filesystem because data that should be in
86 * an inode (if dos had them) resides in the directory itself. Since we
87 * must update directory entries without the benefit of having the vnode
88 * for the directory we must use the vnode for the filesystem. This means
89 * that when a directory is actually read/written (via read, write, or
90 * readdir, or seek) we must use the vnode for the filesystem instead of
91 * the vnode for the directory as would happen in ufs. This is to insure we
92 * retrieve the correct block from the buffer cache since the hash value is
93 * based upon the vnode address and the desired block number.
96 static int msdosfs_wfile(const char *, struct denode *, fsnode *);
97 static void unix2fattime(const struct timespec *tsp, uint16_t *ddp,
101 msdosfs_times(struct denode *dep, const struct stat *st)
106 unix2fattime(&st->st_birthtim, &dep->de_CDate, &dep->de_CTime);
107 unix2fattime(&st->st_atim, &dep->de_ADate, NULL);
108 unix2fattime(&st->st_mtim, &dep->de_MDate, &dep->de_MTime);
112 unix2fattime(const struct timespec *tsp, uint16_t *ddp, uint16_t *dtp)
118 localtime_r(&t1, <);
120 unsigned long fat_time = ((lt.tm_year - 80) << 25) |
121 ((lt.tm_mon + 1) << 21) |
128 *ddp = (uint16_t)(fat_time >> 16);
130 *dtp = (uint16_t)fat_time;
134 * When we search a directory the blocks containing directory entries are
135 * read and examined. The directory entries contain information that would
136 * normally be in the inode of a unix filesystem. This means that some of
137 * a directory's contents may also be in memory resident denodes (sort of
138 * an inode). This can cause problems if we are searching while some other
139 * process is modifying a directory. To prevent one process from accessing
140 * incompletely modified directory information we depend upon being the
141 * sole owner of a directory block. bread/brelse provide this service.
142 * This being the case, when a process modifies a directory it must first
143 * acquire the disk block that contains the directory entry to be modified.
144 * Then update the disk block and the denode, and then write the disk block
145 * out to disk. This way disk blocks containing directory entries and in
146 * memory denode's will be in synch.
149 msdosfs_findslot(struct denode *dp, struct componentname *cnp)
160 struct msdosfsmount *pmp;
162 struct direntry *dep;
163 u_char dosfilename[12];
165 int chksum = -1, chksum_ok;
170 switch (unix2dosfn((const u_char *)cnp->cn_nameptr, dosfilename,
171 cnp->cn_namelen, 0)) {
177 wincnt = winSlotCnt((const u_char *)cnp->cn_nameptr,
178 cnp->cn_namelen) + 1;
182 wincnt = winSlotCnt((const u_char *)cnp->cn_nameptr,
183 cnp->cn_namelen) + 1;
187 if (pmp->pm_flags & MSDOSFSMNT_SHORTNAME)
191 * Suppress search for slots unless creating
192 * file and at end of pathname, in which case
193 * we watch for a place to put the new file in
194 * case it doesn't already exist.
197 MSDOSFS_DPRINTF(("%s(): dos filename: %s\n", __func__, dosfilename));
199 * Search the directory pointed at by vdp for the name pointed at
200 * by cnp->cn_nameptr.
203 * The outer loop ranges over the clusters that make up the
204 * directory. Note that the root directory is different from all
205 * other directories. It has a fixed number of blocks that are not
206 * part of the pool of allocatable clusters. So, we treat it a
207 * little differently. The root directory starts at "cluster" 0.
210 for (frcn = 0; diroff < dp->de_FileSize; frcn++) {
211 if ((error = pcbmap(dp, frcn, &bn, &cluster, &blsize)) != 0) {
216 error = bread(pmp->pm_devvp, bn, blsize, 0, &bp);
220 for (blkoff = 0; blkoff < blsize;
221 blkoff += sizeof(struct direntry),
222 diroff += sizeof(struct direntry)) {
223 dep = (struct direntry *)(bp->b_data + blkoff);
225 * If the slot is empty and we are still looking
226 * for an empty then remember this one. If the
227 * slot is not empty then check to see if it
228 * matches what we are looking for. If the slot
229 * has never been filled with anything, then the
230 * remainder of the directory has never been used,
231 * so there is no point in searching it.
233 if (dep->deName[0] == SLOT_EMPTY ||
234 dep->deName[0] == SLOT_DELETED) {
236 * Drop memory of previous long matches
240 if (slotcount < wincnt) {
244 if (dep->deName[0] == SLOT_EMPTY) {
250 * If there wasn't enough space for our
251 * winentries, forget about the empty space
253 if (slotcount < wincnt)
257 * Check for Win95 long filename entry
259 if (dep->deAttributes == ATTR_WIN95) {
260 if (pmp->pm_flags & MSDOSFSMNT_SHORTNAME)
264 (const u_char *)cnp->cn_nameptr,
266 (struct winentry *)dep, chksum);
271 * Ignore volume labels (anywhere, not just
272 * the root directory).
274 if (dep->deAttributes & ATTR_VOLUME) {
280 * Check for a checksum or name match
282 chksum_ok = (chksum == winChksum(dep->deName));
284 && (!olddos || memcmp(dosfilename, dep->deName, 11))) {
288 MSDOSFS_DPRINTF(("%s(): match blkoff %d, diroff %u\n",
289 __func__, blkoff, diroff));
291 * Remember where this directory
292 * entry came from for whoever did
295 dp->de_fndoffset = diroff;
300 } /* for (blkoff = 0; .... */
302 * Release the buffer holding the directory cluster just
306 } /* for (frcn = 0; ; frcn++) */
310 * We hold no disk buffers at this point.
314 * If we get here we didn't find the entry we were looking for. But
315 * that's ok if we are creating or renaming and are at the end of
316 * the pathname and the directory hasn't been removed.
318 MSDOSFS_DPRINTF(("%s(): refcnt %ld, slotcount %d, slotoffset %d\n",
319 __func__, dp->de_refcnt, slotcount, slotoffset));
321 * Fixup the slot description to point to the place where
322 * we might put the new DOS direntry (putting the Win95
323 * long name entries before that)
329 if (wincnt > slotcount) {
330 slotoffset += sizeof(struct direntry) * (wincnt - slotcount);
334 * Return an indication of where the new directory
335 * entry should be put.
337 dp->de_fndoffset = slotoffset;
338 dp->de_fndcnt = wincnt - 1;
341 * We return with the directory locked, so that
342 * the parameters we set up above will still be
343 * valid if we actually decide to do a direnter().
344 * We return ni_vp == NULL to indicate that the entry
345 * does not currently exist; we leave a pointer to
346 * the (locked) directory inode in ndp->ni_dvp.
348 * NB - if the directory is unlocked, then this
349 * information cannot be used.
355 * Create a regular file. On entry the directory to contain the file being
356 * created is locked. We must release before we return.
359 msdosfs_mkfile(const char *path, struct denode *pdep, fsnode *node)
361 struct componentname cn;
362 struct denode ndirent;
365 struct stat *st = &node->inode->st;
367 cn.cn_nameptr = node->name;
368 cn.cn_namelen = strlen(node->name);
370 MSDOSFS_DPRINTF(("%s(name %s, mode 0%o size %zu)\n",
371 __func__, node->name, st->st_mode, (size_t)st->st_size));
374 * If this is the root directory and there is no space left we
375 * can't do anything. This is because the root directory can not
378 if (pdep->de_StartCluster == MSDOSFSROOT
379 && pdep->de_fndoffset >= pdep->de_FileSize) {
385 * Create a directory entry for the file, then call createde() to
386 * have it installed. NOTE: DOS files are always executable. We
387 * use the absence of the owner write bit to make the file
390 memset(&ndirent, 0, sizeof(ndirent));
391 if ((error = uniqdosname(pdep, &cn, ndirent.de_Name)) != 0)
394 ndirent.de_Attributes = (st->st_mode & S_IWUSR) ?
395 ATTR_ARCHIVE : ATTR_ARCHIVE | ATTR_READONLY;
396 ndirent.de_StartCluster = 0;
397 ndirent.de_FileSize = 0;
398 ndirent.de_pmp = pdep->de_pmp;
399 ndirent.de_flag = DE_ACCESS | DE_CREATE | DE_UPDATE;
400 msdosfs_times(&ndirent, &node->inode->st);
402 if ((error = msdosfs_findslot(pdep, &cn)) != 0)
404 if ((error = createde(&ndirent, pdep, &dep, &cn)) != 0)
406 if ((error = msdosfs_wfile(path, dep, node)) != 0)
415 msdosfs_updatede(struct denode *dep)
418 struct direntry *dirp;
421 dep->de_flag &= ~DE_MODIFIED;
422 error = readde(dep, &bp, &dirp);
425 DE_EXTERNALIZE(dirp, dep);
431 * Write data to a file or directory.
434 msdosfs_wfile(const char *path, struct denode *dep, fsnode *node)
437 size_t osize = dep->de_FileSize;
438 struct stat *st = &node->inode->st;
440 struct msdosfsmount *pmp = dep->de_pmp;
445 error = 0; /* XXX: gcc/vax */
446 MSDOSFS_DPRINTF(("%s(diroff %lu, dirclust %lu, startcluster %lu)\n",
447 __func__, dep->de_diroffset, dep->de_dirclust,
448 dep->de_StartCluster));
449 if (st->st_size == 0)
452 /* Don't bother to try to write files larger than the fs limit */
453 if (st->st_size > MSDOSFS_FILESIZE_MAX)
457 MSDOSFS_DPRINTF(("%s(nsize=%zu, osize=%zu)\n", __func__, nsize, osize));
459 if ((error = deextend(dep, nsize, NULL)) != 0)
461 if ((error = msdosfs_updatede(dep)) != 0)
465 if ((fd = open(path, O_RDONLY)) == -1) {
467 MSDOSFS_DPRINTF(("open %s: %s", path, strerror(error)));
471 if ((dat = mmap(0, nsize, PROT_READ, MAP_FILE | MAP_PRIVATE, fd, 0))
474 MSDOSFS_DPRINTF(("%s: mmap %s: %s", __func__, node->name,
481 for (offs = 0; offs < nsize;) {
484 u_long on = offs & pmp->pm_crbomask;
486 if ((error = pcbmap(dep, cn++, &bn, NULL, &blsize)) != 0) {
487 MSDOSFS_DPRINTF(("%s: pcbmap %lu",
488 __func__, (unsigned long)bn));
492 MSDOSFS_DPRINTF(("%s(cn=%lu, bn=%llu, blsize=%d)\n",
493 __func__, cn, (unsigned long long)bn, blsize));
494 if ((error = bread(pmp->pm_devvp, bn, blsize, 0, &bp)) != 0) {
495 MSDOSFS_DPRINTF(("bread %d\n", error));
498 cpsize = MIN((nsize - offs), blsize - on);
499 memcpy(bp->b_data + on, dat + offs, cpsize);
511 static const struct {
513 struct direntry dotdot;
515 { ". ", /* the . entry */
516 ATTR_DIRECTORY, /* file attribute */
518 0, { 0, 0 }, { 0, 0 }, /* create time & date */
519 { 0, 0 }, /* access date */
520 { 0, 0 }, /* high bits of start cluster */
521 { 210, 4 }, { 210, 4 }, /* modify time & date */
522 { 0, 0 }, /* startcluster */
523 { 0, 0, 0, 0 } /* filesize */
525 { ".. ", /* the .. entry */
526 ATTR_DIRECTORY, /* file attribute */
528 0, { 0, 0 }, { 0, 0 }, /* create time & date */
529 { 0, 0 }, /* access date */
530 { 0, 0 }, /* high bits of start cluster */
531 { 210, 4 }, { 210, 4 }, /* modify time & date */
532 { 0, 0 }, /* startcluster */
533 { 0, 0, 0, 0 } /* filesize */
538 msdosfs_mkdire(const char *path, struct denode *pdep, fsnode *node) {
539 struct denode ndirent;
541 struct componentname cn;
542 struct msdosfsmount *pmp = pdep->de_pmp;
544 u_long newcluster, pcl, bn;
545 struct direntry *denp;
548 cn.cn_nameptr = node->name;
549 cn.cn_namelen = strlen(node->name);
551 * If this is the root directory and there is no space left we
552 * can't do anything. This is because the root directory can not
555 if (pdep->de_StartCluster == MSDOSFSROOT
556 && pdep->de_fndoffset >= pdep->de_FileSize) {
562 * Allocate a cluster to hold the about to be created directory.
564 error = clusteralloc(pmp, 0, 1, CLUST_EOFE, &newcluster, NULL);
568 memset(&ndirent, 0, sizeof(ndirent));
569 ndirent.de_pmp = pmp;
570 ndirent.de_flag = DE_ACCESS | DE_CREATE | DE_UPDATE;
571 msdosfs_times(&ndirent, &node->inode->st);
574 * Now fill the cluster with the "." and ".." entries. And write
575 * the cluster to disk. This way it is there for the parent
576 * directory to be pointing at if there were a crash.
578 bn = cntobn(pmp, newcluster);
579 MSDOSFS_DPRINTF(("%s(newcluster %lu, bn=%lu)\n",
580 __func__, newcluster, bn));
581 /* always succeeds */
582 bp = getblk(pmp->pm_devvp, bn, pmp->pm_bpcluster, 0, 0, 0);
583 memset(bp->b_data, 0, pmp->pm_bpcluster);
584 memcpy(bp->b_data, &dosdirtemplate, sizeof dosdirtemplate);
585 denp = (struct direntry *)bp->b_data;
586 putushort(denp[0].deStartCluster, newcluster);
587 putushort(denp[0].deCDate, ndirent.de_CDate);
588 putushort(denp[0].deCTime, ndirent.de_CTime);
589 denp[0].deCHundredth = ndirent.de_CHun;
590 putushort(denp[0].deADate, ndirent.de_ADate);
591 putushort(denp[0].deMDate, ndirent.de_MDate);
592 putushort(denp[0].deMTime, ndirent.de_MTime);
593 pcl = pdep->de_StartCluster;
594 MSDOSFS_DPRINTF(("%s(pcl %lu, rootdirblk=%lu)\n", __func__, pcl,
595 pmp->pm_rootdirblk));
596 if (FAT32(pmp) && pcl == pmp->pm_rootdirblk)
598 putushort(denp[1].deStartCluster, pcl);
599 putushort(denp[1].deCDate, ndirent.de_CDate);
600 putushort(denp[1].deCTime, ndirent.de_CTime);
601 denp[1].deCHundredth = ndirent.de_CHun;
602 putushort(denp[1].deADate, ndirent.de_ADate);
603 putushort(denp[1].deMDate, ndirent.de_MDate);
604 putushort(denp[1].deMTime, ndirent.de_MTime);
606 putushort(denp[0].deHighClust, newcluster >> 16);
607 putushort(denp[1].deHighClust, pdep->de_StartCluster >> 16);
609 putushort(denp[0].deHighClust, 0);
610 putushort(denp[1].deHighClust, 0);
613 if ((error = bwrite(bp)) != 0)
617 * Now build up a directory entry pointing to the newly allocated
618 * cluster. This will be written to an empty slot in the parent
621 if ((error = uniqdosname(pdep, &cn, ndirent.de_Name)) != 0)
624 ndirent.de_Attributes = ATTR_DIRECTORY;
625 ndirent.de_StartCluster = newcluster;
626 ndirent.de_FileSize = 0;
627 ndirent.de_pmp = pdep->de_pmp;
628 if ((error = msdosfs_findslot(pdep, &cn)) != 0)
630 if ((error = createde(&ndirent, pdep, &dep, &cn)) != 0)
632 if ((error = msdosfs_updatede(dep)) != 0)
637 clusterfree(pmp, newcluster, NULL);