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