1 /* $FreeBSD$ */
2 /* $NetBSD: msdosfs_lookup.c,v 1.37 1997/11/17 15:36:54 ws Exp $ */
3
4 /*-
5 * SPDX-License-Identifier: BSD-4-Clause
6 *
7 * Copyright (C) 1994, 1995, 1997 Wolfgang Solfrank.
8 * Copyright (C) 1994, 1995, 1997 TooLs GmbH.
9 * All rights reserved.
10 * Original code by Paul Popelka (paulp@uts.amdahl.com) (see below).
11 *
12 * Redistribution and use in source and binary forms, with or without
13 * modification, are permitted provided that the following conditions
14 * are met:
15 * 1. Redistributions of source code must retain the above copyright
16 * notice, this list of conditions and the following disclaimer.
17 * 2. Redistributions in binary form must reproduce the above copyright
18 * notice, this list of conditions and the following disclaimer in the
19 * documentation and/or other materials provided with the distribution.
20 * 3. All advertising materials mentioning features or use of this software
21 * must display the following acknowledgement:
22 * This product includes software developed by TooLs GmbH.
23 * 4. The name of TooLs GmbH may not be used to endorse or promote products
24 * derived from this software without specific prior written permission.
25 *
26 * THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``AS IS'' AND ANY EXPRESS OR
27 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
28 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
29 * IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
30 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
31 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
32 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
33 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
34 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
35 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
36 */
37 /*-
38 * Written by Paul Popelka (paulp@uts.amdahl.com)
39 *
40 * You can do anything you want with this software, just don't say you wrote
41 * it, and don't remove this notice.
42 *
43 * This software is provided "as is".
44 *
45 * The author supplies this software to be publicly redistributed on the
46 * understanding that the author is not responsible for the correct
47 * functioning of this software in any circumstances and is not liable for
48 * any damages caused by this software.
49 *
50 * October 1992
51 */
52
53 #include <sys/param.h>
54 #include <sys/systm.h>
55 #include <sys/buf.h>
56 #include <sys/mount.h>
57 #include <sys/namei.h>
58 #include <sys/vnode.h>
59
60 #include <fs/msdosfs/bpb.h>
61 #include <fs/msdosfs/direntry.h>
62 #include <fs/msdosfs/denode.h>
63 #include <fs/msdosfs/fat.h>
64 #include <fs/msdosfs/msdosfsmount.h>
65
66 static int
67 msdosfs_lookup_checker(struct msdosfsmount *pmp, struct vnode *dvp,
68 struct denode *tdp, struct vnode **vpp)
69 {
70 struct vnode *vp;
71
72 vp = DETOV(tdp);
73
74 /*
75 * Lookup assumes that directory cannot be hardlinked.
76 * Corrupted msdosfs filesystem could break this assumption.
77 */
78 if (vp == dvp) {
79 vput(vp);
80 msdosfs_integrity_error(pmp);
81 *vpp = NULL;
82 return (EBADF);
83 }
84
85 *vpp = vp;
86 return (0);
87 }
88
89 int
90 msdosfs_lookup(struct vop_cachedlookup_args *ap)
91 {
92
93 return (msdosfs_lookup_ino(ap->a_dvp, ap->a_vpp, ap->a_cnp, NULL,
94 NULL));
95 }
96
97 struct deget_dotdot {
98 u_long cluster;
99 int blkoff;
100 };
101
102 static int
103 msdosfs_deget_dotdot(struct mount *mp, void *arg, int lkflags,
104 struct vnode **rvp)
105 {
106 struct deget_dotdot *dd_arg;
107 struct denode *rdp;
108 struct msdosfsmount *pmp;
109 int error;
110
111 pmp = VFSTOMSDOSFS(mp);
112 dd_arg = arg;
113 error = deget(pmp, dd_arg->cluster, dd_arg->blkoff,
114 LK_EXCLUSIVE, &rdp);
115 if (error == 0)
116 *rvp = DETOV(rdp);
117 return (error);
118 }
119
120 /*
121 * When we search a directory the blocks containing directory entries are
122 * read and examined. The directory entries contain information that would
123 * normally be in the inode of a unix filesystem. This means that some of
124 * a directory's contents may also be in memory resident denodes (sort of
125 * an inode). This can cause problems if we are searching while some other
126 * process is modifying a directory. To prevent one process from accessing
127 * incompletely modified directory information we depend upon being the
128 * sole owner of a directory block. bread/brelse provide this service.
129 * This being the case, when a process modifies a directory it must first
130 * acquire the disk block that contains the directory entry to be modified.
131 * Then update the disk block and the denode, and then write the disk block
132 * out to disk. This way disk blocks containing directory entries and in
133 * memory denode's will be in synch.
134 */
135 int
136 msdosfs_lookup_ino(struct vnode *vdp, struct vnode **vpp, struct componentname
137 *cnp, daddr_t *scnp, u_long *blkoffp)
138 {
139 struct mbnambuf nb;
140 daddr_t bn;
141 int error;
142 int slotcount;
143 int slotoffset = 0;
144 int frcn;
145 u_long cluster;
146 u_long blkoff;
147 int diroff;
148 int blsize;
149 int isadir; /* ~0 if found direntry is a directory */
150 daddr_t scn; /* starting cluster number */
151 struct vnode *pdp;
152 struct denode *dp;
153 struct denode *tdp;
154 struct msdosfsmount *pmp;
155 struct buf *bp = NULL;
156 struct direntry *dep = NULL;
157 struct deget_dotdot dd_arg;
158 u_char dosfilename[12];
159 int flags = cnp->cn_flags;
160 int nameiop = cnp->cn_nameiop;
161 int unlen;
162 uint64_t inode1;
163
164 int wincnt = 1;
165 int chksum = -1, chksum_ok;
166 int olddos = 1;
167
168 #ifdef MSDOSFS_DEBUG
169 printf("msdosfs_lookup(): looking for %s\n", cnp->cn_nameptr);
170 #endif
171 dp = VTODE(vdp);
172 pmp = dp->de_pmp;
173 #ifdef MSDOSFS_DEBUG
174 printf("msdosfs_lookup(): vdp %p, dp %p, Attr %02x\n",
175 vdp, dp, dp->de_Attributes);
176 #endif
177
178 restart:
179 if (vpp != NULL)
180 *vpp = NULL;
181 /*
182 * If they are going after the . or .. entry in the root directory,
183 * they won't find it. DOS filesystems don't have them in the root
184 * directory. So, we fake it. deget() is in on this scam too.
185 */
186 if ((vdp->v_vflag & VV_ROOT) && cnp->cn_nameptr[0] == '.' &&
187 (cnp->cn_namelen == 1 ||
188 (cnp->cn_namelen == 2 && cnp->cn_nameptr[1] == '.'))) {
189 isadir = ATTR_DIRECTORY;
190 scn = MSDOSFSROOT;
191 #ifdef MSDOSFS_DEBUG
192 printf("msdosfs_lookup(): looking for . or .. in root directory\n");
193 #endif
194 cluster = MSDOSFSROOT;
195 blkoff = MSDOSFSROOT_OFS;
196 goto foundroot;
197 }
198
199 switch (unix2dosfn((const u_char *)cnp->cn_nameptr, dosfilename,
200 cnp->cn_namelen, 0, pmp)) {
201 case 0:
202 return (EINVAL);
203 case 1:
204 break;
205 case 2:
206 wincnt = winSlotCnt((const u_char *)cnp->cn_nameptr,
207 cnp->cn_namelen, pmp) + 1;
208 break;
209 case 3:
210 olddos = 0;
211 wincnt = winSlotCnt((const u_char *)cnp->cn_nameptr,
212 cnp->cn_namelen, pmp) + 1;
213 break;
214 }
215 if (pmp->pm_flags & MSDOSFSMNT_SHORTNAME) {
216 wincnt = 1;
217 olddos = 1;
218 }
219 unlen = winLenFixup(cnp->cn_nameptr, cnp->cn_namelen);
220
221 /*
222 * Suppress search for slots unless creating
223 * file and at end of pathname, in which case
224 * we watch for a place to put the new file in
225 * case it doesn't already exist.
226 */
227 slotcount = wincnt;
228 if ((nameiop == CREATE || nameiop == RENAME) &&
229 (flags & ISLASTCN))
230 slotcount = 0;
231
232 #ifdef MSDOSFS_DEBUG
233 printf("msdosfs_lookup(): dos version of filename %s, length %ld\n",
234 dosfilename, cnp->cn_namelen);
235 #endif
236 /*
237 * Search the directory pointed at by vdp for the name pointed at
238 * by cnp->cn_nameptr.
239 */
240 tdp = NULL;
241 mbnambuf_init(&nb);
242 /*
243 * The outer loop ranges over the clusters that make up the
244 * directory. Note that the root directory is different from all
245 * other directories. It has a fixed number of blocks that are not
246 * part of the pool of allocatable clusters. So, we treat it a
247 * little differently. The root directory starts at "cluster" 0.
248 */
249 diroff = 0;
250 for (frcn = 0;; frcn++) {
251 error = pcbmap(dp, frcn, &bn, &cluster, &blsize);
252 if (error) {
253 if (error == E2BIG)
254 break;
255 return (error);
256 }
257 error = bread(pmp->pm_devvp, bn, blsize, NOCRED, &bp);
258 if (error) {
259 return (error);
260 }
261 for (blkoff = 0; blkoff < blsize;
262 blkoff += sizeof(struct direntry),
263 diroff += sizeof(struct direntry)) {
264 dep = (struct direntry *)(bp->b_data + blkoff);
265 /*
266 * If the slot is empty and we are still looking
267 * for an empty then remember this one. If the
268 * slot is not empty then check to see if it
269 * matches what we are looking for. If the slot
270 * has never been filled with anything, then the
271 * remainder of the directory has never been used,
272 * so there is no point in searching it.
273 */
274 if (dep->deName[0] == SLOT_EMPTY ||
275 dep->deName[0] == SLOT_DELETED) {
276 /*
277 * Drop memory of previous long matches
278 */
279 chksum = -1;
280 mbnambuf_init(&nb);
281
282 if (slotcount < wincnt) {
283 slotcount++;
284 slotoffset = diroff;
285 }
286 if (dep->deName[0] == SLOT_EMPTY) {
287 brelse(bp);
288 goto notfound;
289 }
290 } else {
291 /*
292 * If there wasn't enough space for our winentries,
293 * forget about the empty space
294 */
295 if (slotcount < wincnt)
296 slotcount = 0;
297
298 /*
299 * Check for Win95 long filename entry
300 */
301 if (dep->deAttributes == ATTR_WIN95) {
302 if (pmp->pm_flags & MSDOSFSMNT_SHORTNAME)
303 continue;
304
305 chksum = win2unixfn(&nb,
306 (struct winentry *)dep, chksum,
307 pmp);
308 continue;
309 }
310
311 chksum = winChkName(&nb,
312 (const u_char *)cnp->cn_nameptr, unlen,
313 chksum, pmp);
314 if (chksum == -2) {
315 chksum = -1;
316 continue;
317 }
318
319 /*
320 * Ignore volume labels (anywhere, not just
321 * the root directory).
322 */
323 if (dep->deAttributes & ATTR_VOLUME) {
324 chksum = -1;
325 continue;
326 }
327
328 /*
329 * Check for a checksum or name match
330 */
331 chksum_ok = (chksum == winChksum(dep->deName));
332 if (!chksum_ok
333 && (!olddos || bcmp(dosfilename, dep->deName, 11))) {
334 chksum = -1;
335 continue;
336 }
337 #ifdef MSDOSFS_DEBUG
338 printf("msdosfs_lookup(): match blkoff %d, diroff %d\n",
339 blkoff, diroff);
340 #endif
341 /*
342 * Remember where this directory
343 * entry came from for whoever did
344 * this lookup.
345 */
346 dp->de_fndoffset = diroff;
347 if (chksum_ok && nameiop == RENAME) {
348 /*
349 * Target had correct long name
350 * directory entries, reuse them
351 * as needed.
352 */
353 dp->de_fndcnt = wincnt - 1;
354 } else {
355 /*
356 * Long name directory entries
357 * not present or corrupt, can only
358 * reuse dos directory entry.
359 */
360 dp->de_fndcnt = 0;
361 }
362
363 goto found;
364 }
365 } /* for (blkoff = 0; .... */
366 /*
367 * Release the buffer holding the directory cluster just
368 * searched.
369 */
370 brelse(bp);
371 } /* for (frcn = 0; ; frcn++) */
372
373 notfound:
374 /*
375 * We hold no disk buffers at this point.
376 */
377
378 /*
379 * Fixup the slot description to point to the place where
380 * we might put the new DOS direntry (putting the Win95
381 * long name entries before that)
382 */
383 if (!slotcount) {
384 slotcount = 1;
385 slotoffset = diroff;
386 }
387 if (wincnt > slotcount)
388 slotoffset += sizeof(struct direntry) * (wincnt - slotcount);
389
390 /*
391 * If we get here we didn't find the entry we were looking for. But
392 * that's ok if we are creating or renaming and are at the end of
393 * the pathname and the directory hasn't been removed.
394 */
395 #ifdef MSDOSFS_DEBUG
396 printf("msdosfs_lookup(): op %d, refcnt %ld\n",
397 nameiop, dp->de_refcnt);
398 printf(" slotcount %d, slotoffset %d\n",
399 slotcount, slotoffset);
400 #endif
401 if ((nameiop == CREATE || nameiop == RENAME) &&
402 (flags & ISLASTCN) && dp->de_refcnt != 0) {
403 /*
404 * Access for write is interpreted as allowing
405 * creation of files in the directory.
406 */
407 error = VOP_ACCESS(vdp, VWRITE, cnp->cn_cred, cnp->cn_thread);
408 if (error)
409 return (error);
410 /*
411 * Return an indication of where the new directory
412 * entry should be put.
413 */
414 dp->de_fndoffset = slotoffset;
415 dp->de_fndcnt = wincnt - 1;
416
417 /*
418 * We return with the directory locked, so that
419 * the parameters we set up above will still be
420 * valid if we actually decide to do a direnter().
421 * We return ni_vp == NULL to indicate that the entry
422 * does not currently exist; we leave a pointer to
423 * the (locked) directory inode in ndp->ni_dvp.
424 * The pathname buffer is saved so that the name
425 * can be obtained later.
426 *
427 * NB - if the directory is unlocked, then this
428 * information cannot be used.
429 */
430 cnp->cn_flags |= SAVENAME;
431 return (EJUSTRETURN);
432 }
433 #if 0
434 /*
435 * Insert name into cache (as non-existent) if appropriate.
436 *
437 * XXX Negative caching is broken for msdosfs because the name
438 * cache doesn't understand peculiarities such as case insensitivity
439 * and 8.3 filenames. Hence, it may not invalidate all negative
440 * entries if a file with this name is later created.
441 */
442 if ((cnp->cn_flags & MAKEENTRY) != 0)
443 cache_enter(vdp, *vpp, cnp);
444 #endif
445 return (ENOENT);
446
447 found:
448 /*
449 * NOTE: We still have the buffer with matched directory entry at
450 * this point.
451 */
452 isadir = dep->deAttributes & ATTR_DIRECTORY;
453 scn = getushort(dep->deStartCluster);
454 if (FAT32(pmp)) {
455 scn |= getushort(dep->deHighClust) << 16;
456 if (scn == pmp->pm_rootdirblk) {
457 /*
458 * There should actually be 0 here.
459 * Just ignore the error.
460 */
461 scn = MSDOSFSROOT;
462 }
463 }
464
465 if (isadir) {
466 cluster = scn;
467 if (cluster == MSDOSFSROOT)
468 blkoff = MSDOSFSROOT_OFS;
469 else
470 blkoff = 0;
471 } else if (cluster == MSDOSFSROOT)
472 blkoff = diroff;
473
474 /*
475 * Now release buf to allow deget to read the entry again.
476 * Reserving it here and giving it to deget could result
477 * in a deadlock.
478 */
479 brelse(bp);
480 bp = NULL;
481
482 foundroot:
483 /*
484 * If we entered at foundroot, then we are looking for the . or ..
485 * entry of the filesystems root directory. isadir and scn were
486 * setup before jumping here. And, bp is already null.
487 */
488 if (FAT32(pmp) && scn == MSDOSFSROOT)
489 scn = pmp->pm_rootdirblk;
490
491 if (scnp != NULL) {
492 *scnp = cluster;
493 *blkoffp = blkoff;
494 return (0);
495 }
496
497 /*
498 * If deleting, and at end of pathname, return
499 * parameters which can be used to remove file.
500 */
501 if (nameiop == DELETE && (flags & ISLASTCN)) {
502 /*
503 * Don't allow deleting the root.
504 */
505 if (blkoff == MSDOSFSROOT_OFS)
506 return (EBUSY);
507
508 /*
509 * Write access to directory required to delete files.
510 */
511 error = VOP_ACCESS(vdp, VWRITE, cnp->cn_cred, cnp->cn_thread);
512 if (error)
513 return (error);
514
515 /*
516 * Return pointer to current entry in dp->i_offset.
517 * Save directory inode pointer in ndp->ni_dvp for dirremove().
518 */
519 if (dp->de_StartCluster == scn && isadir) { /* "." */
520 VREF(vdp);
521 *vpp = vdp;
522 return (0);
523 }
524 error = deget(pmp, cluster, blkoff, LK_EXCLUSIVE, &tdp);
525 if (error)
526 return (error);
527 return (msdosfs_lookup_checker(pmp, vdp, tdp, vpp));
528 }
529
530 /*
531 * If rewriting (RENAME), return the inode and the
532 * information required to rewrite the present directory
533 * Must get inode of directory entry to verify it's a
534 * regular file, or empty directory.
535 */
536 if (nameiop == RENAME && (flags & ISLASTCN)) {
537 if (blkoff == MSDOSFSROOT_OFS)
538 return (EBUSY);
539
540 error = VOP_ACCESS(vdp, VWRITE, cnp->cn_cred, cnp->cn_thread);
541 if (error)
542 return (error);
543
544 /*
545 * Careful about locking second inode.
546 * This can only occur if the target is ".".
547 */
548 if (dp->de_StartCluster == scn && isadir)
549 return (EISDIR);
550
551 if ((error = deget(pmp, cluster, blkoff, LK_EXCLUSIVE,
552 &tdp)) != 0)
553 return (error);
554 if ((error = msdosfs_lookup_checker(pmp, vdp, tdp, vpp))
555 != 0)
556 return (error);
557 cnp->cn_flags |= SAVENAME;
558 return (0);
559 }
560
561 /*
562 * Step through the translation in the name. We do not `vput' the
563 * directory because we may need it again if a symbolic link
564 * is relative to the current directory. Instead we save it
565 * unlocked as "pdp". We must get the target inode before unlocking
566 * the directory to insure that the inode will not be removed
567 * before we get it. We prevent deadlock by always fetching
568 * inodes from the root, moving down the directory tree. Thus
569 * when following backward pointers ".." we must unlock the
570 * parent directory before getting the requested directory.
571 */
572 pdp = vdp;
573 if (flags & ISDOTDOT) {
574 dd_arg.cluster = cluster;
575 dd_arg.blkoff = blkoff;
576 error = vn_vget_ino_gen(vdp, msdosfs_deget_dotdot,
577 &dd_arg, cnp->cn_lkflags, vpp);
578 if (error != 0) {
579 *vpp = NULL;
580 return (error);
581 }
582 /*
583 * Recheck that ".." still points to the inode we
584 * looked up before pdp lock was dropped.
585 */
586 error = msdosfs_lookup_ino(pdp, NULL, cnp, &scn, &blkoff);
587 if (error) {
588 vput(*vpp);
589 *vpp = NULL;
590 return (error);
591 }
592 if (FAT32(pmp) && scn == MSDOSFSROOT)
593 scn = pmp->pm_rootdirblk;
594 inode1 = scn * pmp->pm_bpcluster + blkoff;
595 if (VTODE(*vpp)->de_inode != inode1) {
596 vput(*vpp);
597 goto restart;
598 }
599 error = msdosfs_lookup_checker(pmp, vdp, VTODE(*vpp), vpp);
600 if (error != 0)
601 return (error);
602 } else if (dp->de_StartCluster == scn && isadir) {
603 if (cnp->cn_namelen != 1 || cnp->cn_nameptr[0] != '.') {
604 /* fs is corrupted, non-dot lookup returned dvp */
605 msdosfs_integrity_error(pmp);
606 return (EBADF);
607 }
608 VREF(vdp); /* we want ourself, ie "." */
609 *vpp = vdp;
610 } else {
611 if ((error = deget(pmp, cluster, blkoff, LK_EXCLUSIVE,
612 &tdp)) != 0)
613 return (error);
614 if ((error = msdosfs_lookup_checker(pmp, vdp, tdp, vpp)) != 0)
615 return (error);
616 }
617
618 /*
619 * Insert name into cache if appropriate.
620 */
621 if (cnp->cn_flags & MAKEENTRY)
622 cache_enter(vdp, *vpp, cnp);
623 return (0);
624 }
625
626 /*
627 * dep - directory entry to copy into the directory
628 * ddep - directory to add to
629 * depp - return the address of the denode for the created directory entry
630 * if depp != 0
631 * cnp - componentname needed for Win95 long filenames
632 */
633 int
634 createde(struct denode *dep, struct denode *ddep, struct denode **depp,
635 struct componentname *cnp)
636 {
637 int error;
638 u_long dirclust, diroffset;
639 struct direntry *ndep;
640 struct msdosfsmount *pmp = ddep->de_pmp;
641 struct buf *bp;
642 daddr_t bn;
643 int blsize;
644
645 #ifdef MSDOSFS_DEBUG
646 printf("createde(dep %p, ddep %p, depp %p, cnp %p)\n",
647 dep, ddep, depp, cnp);
648 #endif
649
650 /*
651 * If no space left in the directory then allocate another cluster
652 * and chain it onto the end of the file. There is one exception
653 * to this. That is, if the root directory has no more space it
654 * can NOT be expanded. extendfile() checks for and fails attempts
655 * to extend the root directory. We just return an error in that
656 * case.
657 */
658 if (ddep->de_fndoffset >= ddep->de_FileSize) {
659 diroffset = ddep->de_fndoffset + sizeof(struct direntry)
660 - ddep->de_FileSize;
661 dirclust = de_clcount(pmp, diroffset);
662 error = extendfile(ddep, dirclust, 0, 0, DE_CLEAR);
663 if (error) {
664 (void)detrunc(ddep, ddep->de_FileSize, 0, NOCRED);
665 return error;
666 }
667
668 /*
669 * Update the size of the directory
670 */
671 ddep->de_FileSize += de_cn2off(pmp, dirclust);
672 }
673
674 /*
675 * We just read in the cluster with space. Copy the new directory
676 * entry in. Then write it to disk. NOTE: DOS directories
677 * do not get smaller as clusters are emptied.
678 */
679 error = pcbmap(ddep, de_cluster(pmp, ddep->de_fndoffset),
680 &bn, &dirclust, &blsize);
681 if (error)
682 return error;
683 diroffset = ddep->de_fndoffset;
684 if (dirclust != MSDOSFSROOT)
685 diroffset &= pmp->pm_crbomask;
686 if ((error = bread(pmp->pm_devvp, bn, blsize, NOCRED, &bp)) != 0) {
687 brelse(bp);
688 return error;
689 }
690 ndep = bptoep(pmp, bp, ddep->de_fndoffset);
691
692 DE_EXTERNALIZE(ndep, dep);
693
694 /*
695 * Now write the Win95 long name
696 */
697 if (ddep->de_fndcnt > 0) {
698 uint8_t chksum = winChksum(ndep->deName);
699 const u_char *un = (const u_char *)cnp->cn_nameptr;
700 int unlen = cnp->cn_namelen;
701 int cnt = 1;
702
703 while (--ddep->de_fndcnt >= 0) {
704 if (!(ddep->de_fndoffset & pmp->pm_crbomask)) {
705 if (DOINGASYNC(DETOV(ddep)))
706 bdwrite(bp);
707 else if ((error = bwrite(bp)) != 0)
708 return error;
709
710 ddep->de_fndoffset -= sizeof(struct direntry);
711 error = pcbmap(ddep,
712 de_cluster(pmp,
713 ddep->de_fndoffset),
714 &bn, 0, &blsize);
715 if (error)
716 return error;
717
718 error = bread(pmp->pm_devvp, bn, blsize,
719 NOCRED, &bp);
720 if (error) {
721 return error;
722 }
723 ndep = bptoep(pmp, bp, ddep->de_fndoffset);
724 } else {
725 ndep--;
726 ddep->de_fndoffset -= sizeof(struct direntry);
727 }
728 if (!unix2winfn(un, unlen, (struct winentry *)ndep,
729 cnt++, chksum, pmp))
730 break;
731 }
732 }
733
734 if (DOINGASYNC(DETOV(ddep)))
735 bdwrite(bp);
736 else if ((error = bwrite(bp)) != 0)
737 return error;
738
739 /*
740 * If they want us to return with the denode gotten.
741 */
742 if (depp) {
743 if (dep->de_Attributes & ATTR_DIRECTORY) {
744 dirclust = dep->de_StartCluster;
745 if (FAT32(pmp) && dirclust == pmp->pm_rootdirblk)
746 dirclust = MSDOSFSROOT;
747 if (dirclust == MSDOSFSROOT)
748 diroffset = MSDOSFSROOT_OFS;
749 else
750 diroffset = 0;
751 }
752 return (deget(pmp, dirclust, diroffset, LK_EXCLUSIVE, depp));
753 }
754
755 return 0;
756 }
757
758 /*
759 * Be sure a directory is empty except for "." and "..". Return 1 if empty,
760 * return 0 if not empty or error.
761 */
762 int
763 dosdirempty(struct denode *dep)
764 {
765 int blsize;
766 int error;
767 u_long cn;
768 daddr_t bn;
769 struct buf *bp;
770 struct msdosfsmount *pmp = dep->de_pmp;
771 struct direntry *dentp;
772
773 /*
774 * Since the filesize field in directory entries for a directory is
775 * zero, we just have to feel our way through the directory until
776 * we hit end of file.
777 */
778 for (cn = 0;; cn++) {
779 if ((error = pcbmap(dep, cn, &bn, 0, &blsize)) != 0) {
780 if (error == E2BIG)
781 return (1); /* it's empty */
782 return (0);
783 }
784 error = bread(pmp->pm_devvp, bn, blsize, NOCRED, &bp);
785 if (error) {
786 return (0);
787 }
788 for (dentp = (struct direntry *)bp->b_data;
789 (char *)dentp < bp->b_data + blsize;
790 dentp++) {
791 if (dentp->deName[0] != SLOT_DELETED &&
792 (dentp->deAttributes & ATTR_VOLUME) == 0) {
793 /*
794 * In dos directories an entry whose name
795 * starts with SLOT_EMPTY (0) starts the
796 * beginning of the unused part of the
797 * directory, so we can just return that it
798 * is empty.
799 */
800 if (dentp->deName[0] == SLOT_EMPTY) {
801 brelse(bp);
802 return (1);
803 }
804 /*
805 * Any names other than "." and ".." in a
806 * directory mean it is not empty.
807 */
808 if (bcmp(dentp->deName, ". ", 11) &&
809 bcmp(dentp->deName, ".. ", 11)) {
810 brelse(bp);
811 #ifdef MSDOSFS_DEBUG
812 printf("dosdirempty(): entry found %02x, %02x\n",
813 dentp->deName[0], dentp->deName[1]);
814 #endif
815 return (0); /* not empty */
816 }
817 }
818 }
819 brelse(bp);
820 }
821 /* NOTREACHED */
822 }
823
824 /*
825 * Check to see if the directory described by target is in some
826 * subdirectory of source. This prevents something like the following from
827 * succeeding and leaving a bunch or files and directories orphaned. mv
828 * /a/b/c /a/b/c/d/e/f Where c and f are directories.
829 *
830 * source - the inode for /a/b/c
831 * target - the inode for /a/b/c/d/e/f
832 *
833 * Returns 0 if target is NOT a subdirectory of source.
834 * Otherwise returns a non-zero error number.
835 */
836 int
837 doscheckpath(struct denode *source, struct denode *target, daddr_t *wait_scn)
838 {
839 daddr_t scn;
840 struct msdosfsmount *pmp;
841 struct direntry *ep;
842 struct denode *dep;
843 struct buf *bp = NULL;
844 int error = 0;
845
846 *wait_scn = 0;
847
848 pmp = target->de_pmp;
849 lockmgr_assert(&pmp->pm_checkpath_lock, KA_XLOCKED);
850 KASSERT(pmp == source->de_pmp,
851 ("doscheckpath: source and target on different filesystems"));
852
853 if ((target->de_Attributes & ATTR_DIRECTORY) == 0 ||
854 (source->de_Attributes & ATTR_DIRECTORY) == 0)
855 return (ENOTDIR);
856
857 if (target->de_StartCluster == source->de_StartCluster)
858 return (EEXIST);
859
860 if (target->de_StartCluster == MSDOSFSROOT ||
861 (FAT32(pmp) && target->de_StartCluster == pmp->pm_rootdirblk))
862 return (0);
863
864 dep = target;
865 vget(DETOV(dep), LK_EXCLUSIVE);
866 for (;;) {
867 if ((dep->de_Attributes & ATTR_DIRECTORY) == 0) {
868 error = ENOTDIR;
869 break;
870 }
871 scn = dep->de_StartCluster;
872 error = bread(pmp->pm_devvp, cntobn(pmp, scn),
873 pmp->pm_bpcluster, NOCRED, &bp);
874 if (error != 0)
875 break;
876
877 ep = (struct direntry *)bp->b_data + 1;
878 if ((ep->deAttributes & ATTR_DIRECTORY) == 0 ||
879 bcmp(ep->deName, ".. ", 11) != 0) {
880 error = ENOTDIR;
881 brelse(bp);
882 break;
883 }
884
885 scn = getushort(ep->deStartCluster);
886 if (FAT32(pmp))
887 scn |= getushort(ep->deHighClust) << 16;
888 brelse(bp);
889
890 if (scn == source->de_StartCluster) {
891 error = EINVAL;
892 break;
893 }
894 if (scn == MSDOSFSROOT)
895 break;
896 if (FAT32(pmp) && scn == pmp->pm_rootdirblk) {
897 /*
898 * scn should be 0 in this case,
899 * but we silently ignore the error.
900 */
901 break;
902 }
903
904 vput(DETOV(dep));
905 dep = NULL;
906 /* NOTE: deget() clears dep on error */
907 error = deget(pmp, scn, 0, LK_EXCLUSIVE | LK_NOWAIT, &dep);
908 if (error != 0) {
909 *wait_scn = scn;
910 break;
911 }
912 }
913 #ifdef MSDOSFS_DEBUG
914 if (error == ENOTDIR)
915 printf("doscheckpath(): .. not a directory?\n");
916 #endif
917 if (dep != NULL)
918 vput(DETOV(dep));
919 return (error);
920 }
921
922 /*
923 * Read in the disk block containing the directory entry (dirclu, dirofs)
924 * and return the address of the buf header, and the address of the
925 * directory entry within the block.
926 */
927 int
928 readep(struct msdosfsmount *pmp, u_long dirclust, u_long diroffset,
929 struct buf **bpp, struct direntry **epp)
930 {
931 int error;
932 daddr_t bn;
933 int blsize;
934
935 blsize = pmp->pm_bpcluster;
936 if (dirclust == MSDOSFSROOT
937 && de_blk(pmp, diroffset + blsize) > pmp->pm_rootdirsize)
938 blsize = de_bn2off(pmp, pmp->pm_rootdirsize) & pmp->pm_crbomask;
939 bn = detobn(pmp, dirclust, diroffset);
940 if ((error = bread(pmp->pm_devvp, bn, blsize, NOCRED, bpp)) != 0) {
941 brelse(*bpp);
942 *bpp = NULL;
943 return (error);
944 }
945 if (epp)
946 *epp = bptoep(pmp, *bpp, diroffset);
947 return (0);
948 }
949
950 /*
951 * Read in the disk block containing the directory entry dep came from and
952 * return the address of the buf header, and the address of the directory
953 * entry within the block.
954 */
955 int
956 readde(struct denode *dep, struct buf **bpp, struct direntry **epp)
957 {
958
959 return (readep(dep->de_pmp, dep->de_dirclust, dep->de_diroffset,
960 bpp, epp));
961 }
962
963 /*
964 * Remove a directory entry. At this point the file represented by the
965 * directory entry to be removed is still full length until no one has it
966 * open. When the file no longer being used msdosfs_inactive() is called
967 * and will truncate the file to 0 length. When the vnode containing the
968 * denode is needed for some other purpose by VFS it will call
969 * msdosfs_reclaim() which will remove the denode from the denode cache.
970 *
971 * pdep directory where the entry is removed
972 * dep file to be removed
973 */
974 int
975 removede(struct denode *pdep, struct denode *dep)
976 {
977 int error;
978 struct direntry *ep;
979 struct buf *bp;
980 daddr_t bn;
981 int blsize;
982 struct msdosfsmount *pmp = pdep->de_pmp;
983 u_long offset = pdep->de_fndoffset;
984
985 #ifdef MSDOSFS_DEBUG
986 printf("removede(): filename %s, dep %p, offset %08lx\n",
987 dep->de_Name, dep, offset);
988 #endif
989
990 dep->de_refcnt--;
991 offset += sizeof(struct direntry);
992 do {
993 offset -= sizeof(struct direntry);
994 error = pcbmap(pdep, de_cluster(pmp, offset), &bn, 0, &blsize);
995 if (error)
996 return error;
997 error = bread(pmp->pm_devvp, bn, blsize, NOCRED, &bp);
998 if (error) {
999 return error;
1000 }
1001 ep = bptoep(pmp, bp, offset);
1002 /*
1003 * Check whether, if we came here the second time, i.e.
1004 * when underflowing into the previous block, the last
1005 * entry in this block is a longfilename entry, too.
1006 */
1007 if (ep->deAttributes != ATTR_WIN95
1008 && offset != pdep->de_fndoffset) {
1009 brelse(bp);
1010 break;
1011 }
1012 offset += sizeof(struct direntry);
1013 while (1) {
1014 /*
1015 * We are a bit aggressive here in that we delete any Win95
1016 * entries preceding this entry, not just the ones we "own".
1017 * Since these presumably aren't valid anyway,
1018 * there should be no harm.
1019 */
1020 offset -= sizeof(struct direntry);
1021 ep--->deName[0] = SLOT_DELETED;
1022 if ((pmp->pm_flags & MSDOSFSMNT_NOWIN95)
1023 || !(offset & pmp->pm_crbomask)
1024 || ep->deAttributes != ATTR_WIN95)
1025 break;
1026 }
1027 if (DOINGASYNC(DETOV(pdep)))
1028 bdwrite(bp);
1029 else if ((error = bwrite(bp)) != 0)
1030 return error;
1031 } while (!(pmp->pm_flags & MSDOSFSMNT_NOWIN95)
1032 && !(offset & pmp->pm_crbomask)
1033 && offset);
1034 return 0;
1035 }
1036
1037 /*
1038 * Create a unique DOS name in dvp
1039 */
1040 int
1041 uniqdosname(struct denode *dep, struct componentname *cnp, u_char *cp)
1042 {
1043 struct msdosfsmount *pmp = dep->de_pmp;
1044 struct direntry *dentp;
1045 int gen;
1046 int blsize;
1047 u_long cn;
1048 daddr_t bn;
1049 struct buf *bp;
1050 int error;
1051
1052 if (pmp->pm_flags & MSDOSFSMNT_SHORTNAME)
1053 return (unix2dosfn((const u_char *)cnp->cn_nameptr, cp,
1054 cnp->cn_namelen, 0, pmp) ? 0 : EINVAL);
1055
1056 for (gen = 1;; gen++) {
1057 /*
1058 * Generate DOS name with generation number
1059 */
1060 if (!unix2dosfn((const u_char *)cnp->cn_nameptr, cp,
1061 cnp->cn_namelen, gen, pmp))
1062 return gen == 1 ? EINVAL : EEXIST;
1063
1064 /*
1065 * Now look for a dir entry with this exact name
1066 */
1067 for (cn = error = 0; !error; cn++) {
1068 if ((error = pcbmap(dep, cn, &bn, 0, &blsize)) != 0) {
1069 if (error == E2BIG) /* EOF reached and not found */
1070 return 0;
1071 return error;
1072 }
1073 error = bread(pmp->pm_devvp, bn, blsize, NOCRED, &bp);
1074 if (error) {
1075 return error;
1076 }
1077 for (dentp = (struct direntry *)bp->b_data;
1078 (char *)dentp < bp->b_data + blsize;
1079 dentp++) {
1080 if (dentp->deName[0] == SLOT_EMPTY) {
1081 /*
1082 * Last used entry and not found
1083 */
1084 brelse(bp);
1085 return 0;
1086 }
1087 /*
1088 * Ignore volume labels and Win95 entries
1089 */
1090 if (dentp->deAttributes & ATTR_VOLUME)
1091 continue;
1092 if (!bcmp(dentp->deName, cp, 11)) {
1093 error = EEXIST;
1094 break;
1095 }
1096 }
1097 brelse(bp);
1098 }
1099 }
1100 }
Cache object: 232e414b86c99cf0e22d20bf98840fc6
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