1 /* $FreeBSD: releng/6.0/sys/fs/msdosfs/msdosfs_lookup.c 145174 2005-04-16 23:47:19Z das $ */
2 /* $NetBSD: msdosfs_lookup.c,v 1.37 1997/11/17 15:36:54 ws Exp $ */
3
4 /*-
5 * Copyright (C) 1994, 1995, 1997 Wolfgang Solfrank.
6 * Copyright (C) 1994, 1995, 1997 TooLs GmbH.
7 * All rights reserved.
8 * Original code by Paul Popelka (paulp@uts.amdahl.com) (see below).
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 3. All advertising materials mentioning features or use of this software
19 * must display the following acknowledgement:
20 * This product includes software developed by TooLs GmbH.
21 * 4. The name of TooLs GmbH may not be used to endorse or promote products
22 * derived from this software without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``AS IS'' AND ANY EXPRESS OR
25 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
26 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
27 * IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
28 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
29 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
30 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
31 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
32 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
33 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
34 */
35 /*-
36 * Written by Paul Popelka (paulp@uts.amdahl.com)
37 *
38 * You can do anything you want with this software, just don't say you wrote
39 * it, and don't remove this notice.
40 *
41 * This software is provided "as is".
42 *
43 * The author supplies this software to be publicly redistributed on the
44 * understanding that the author is not responsible for the correct
45 * functioning of this software in any circumstances and is not liable for
46 * any damages caused by this software.
47 *
48 * October 1992
49 */
50
51 #include <sys/param.h>
52 #include <sys/systm.h>
53 #include <sys/namei.h>
54 #include <sys/bio.h>
55 #include <sys/buf.h>
56 #include <sys/vnode.h>
57 #include <sys/mount.h>
58
59 #include <fs/msdosfs/bpb.h>
60 #include <fs/msdosfs/msdosfsmount.h>
61 #include <fs/msdosfs/direntry.h>
62 #include <fs/msdosfs/denode.h>
63 #include <fs/msdosfs/fat.h>
64
65 /*
66 * When we search a directory the blocks containing directory entries are
67 * read and examined. The directory entries contain information that would
68 * normally be in the inode of a unix filesystem. This means that some of
69 * a directory's contents may also be in memory resident denodes (sort of
70 * an inode). This can cause problems if we are searching while some other
71 * process is modifying a directory. To prevent one process from accessing
72 * incompletely modified directory information we depend upon being the
73 * sole owner of a directory block. bread/brelse provide this service.
74 * This being the case, when a process modifies a directory it must first
75 * acquire the disk block that contains the directory entry to be modified.
76 * Then update the disk block and the denode, and then write the disk block
77 * out to disk. This way disk blocks containing directory entries and in
78 * memory denode's will be in synch.
79 */
80 int
81 msdosfs_lookup(ap)
82 struct vop_cachedlookup_args /* {
83 struct vnode *a_dvp;
84 struct vnode **a_vpp;
85 struct componentname *a_cnp;
86 } */ *ap;
87 {
88 struct vnode *vdp = ap->a_dvp;
89 struct vnode **vpp = ap->a_vpp;
90 struct componentname *cnp = ap->a_cnp;
91 daddr_t bn;
92 int error;
93 int slotcount;
94 int slotoffset = 0;
95 int frcn;
96 u_long cluster;
97 int blkoff;
98 int diroff;
99 int blsize;
100 int isadir; /* ~0 if found direntry is a directory */
101 u_long scn; /* starting cluster number */
102 struct vnode *pdp;
103 struct denode *dp;
104 struct denode *tdp;
105 struct msdosfsmount *pmp;
106 struct buf *bp = 0;
107 struct direntry *dep = NULL;
108 u_char dosfilename[12];
109 int flags = cnp->cn_flags;
110 int nameiop = cnp->cn_nameiop;
111 struct thread *td = cnp->cn_thread;
112 int unlen;
113
114 int wincnt = 1;
115 int chksum = -1, chksum_ok;
116 int olddos = 1;
117
118 #ifdef MSDOSFS_DEBUG
119 printf("msdosfs_lookup(): looking for %s\n", cnp->cn_nameptr);
120 #endif
121 dp = VTODE(vdp);
122 pmp = dp->de_pmp;
123 *vpp = NULL;
124 #ifdef MSDOSFS_DEBUG
125 printf("msdosfs_lookup(): vdp %p, dp %p, Attr %02x\n",
126 vdp, dp, dp->de_Attributes);
127 #endif
128
129 /*
130 * If they are going after the . or .. entry in the root directory,
131 * they won't find it. DOS filesystems don't have them in the root
132 * directory. So, we fake it. deget() is in on this scam too.
133 */
134 if ((vdp->v_vflag & VV_ROOT) && cnp->cn_nameptr[0] == '.' &&
135 (cnp->cn_namelen == 1 ||
136 (cnp->cn_namelen == 2 && cnp->cn_nameptr[1] == '.'))) {
137 isadir = ATTR_DIRECTORY;
138 scn = MSDOSFSROOT;
139 #ifdef MSDOSFS_DEBUG
140 printf("msdosfs_lookup(): looking for . or .. in root directory\n");
141 #endif
142 cluster = MSDOSFSROOT;
143 blkoff = MSDOSFSROOT_OFS;
144 goto foundroot;
145 }
146
147 switch (unix2dosfn((const u_char *)cnp->cn_nameptr, dosfilename,
148 cnp->cn_namelen, 0, pmp)) {
149 case 0:
150 return (EINVAL);
151 case 1:
152 break;
153 case 2:
154 wincnt = winSlotCnt((const u_char *)cnp->cn_nameptr,
155 cnp->cn_namelen, pmp) + 1;
156 break;
157 case 3:
158 olddos = 0;
159 wincnt = winSlotCnt((const u_char *)cnp->cn_nameptr,
160 cnp->cn_namelen, pmp) + 1;
161 break;
162 }
163 if (pmp->pm_flags & MSDOSFSMNT_SHORTNAME) {
164 wincnt = 1;
165 olddos = 1;
166 }
167 unlen = winLenFixup(cnp->cn_nameptr, cnp->cn_namelen);
168
169 /*
170 * Suppress search for slots unless creating
171 * file and at end of pathname, in which case
172 * we watch for a place to put the new file in
173 * case it doesn't already exist.
174 */
175 slotcount = wincnt;
176 if ((nameiop == CREATE || nameiop == RENAME) &&
177 (flags & ISLASTCN))
178 slotcount = 0;
179
180 #ifdef MSDOSFS_DEBUG
181 printf("msdosfs_lookup(): dos version of filename %s, length %ld\n",
182 dosfilename, cnp->cn_namelen);
183 #endif
184 /*
185 * Search the directory pointed at by vdp for the name pointed at
186 * by cnp->cn_nameptr.
187 */
188 tdp = NULL;
189 mbnambuf_init();
190 /*
191 * The outer loop ranges over the clusters that make up the
192 * directory. Note that the root directory is different from all
193 * other directories. It has a fixed number of blocks that are not
194 * part of the pool of allocatable clusters. So, we treat it a
195 * little differently. The root directory starts at "cluster" 0.
196 */
197 diroff = 0;
198 for (frcn = 0;; frcn++) {
199 error = pcbmap(dp, frcn, &bn, &cluster, &blsize);
200 if (error) {
201 if (error == E2BIG)
202 break;
203 return (error);
204 }
205 error = bread(pmp->pm_devvp, bn, blsize, NOCRED, &bp);
206 if (error) {
207 brelse(bp);
208 return (error);
209 }
210 for (blkoff = 0; blkoff < blsize;
211 blkoff += sizeof(struct direntry),
212 diroff += sizeof(struct direntry)) {
213 dep = (struct direntry *)(bp->b_data + blkoff);
214 /*
215 * If the slot is empty and we are still looking
216 * for an empty then remember this one. If the
217 * slot is not empty then check to see if it
218 * matches what we are looking for. If the slot
219 * has never been filled with anything, then the
220 * remainder of the directory has never been used,
221 * so there is no point in searching it.
222 */
223 if (dep->deName[0] == SLOT_EMPTY ||
224 dep->deName[0] == SLOT_DELETED) {
225 /*
226 * Drop memory of previous long matches
227 */
228 chksum = -1;
229 mbnambuf_init();
230
231 if (slotcount < wincnt) {
232 slotcount++;
233 slotoffset = diroff;
234 }
235 if (dep->deName[0] == SLOT_EMPTY) {
236 brelse(bp);
237 goto notfound;
238 }
239 } else {
240 /*
241 * If there wasn't enough space for our winentries,
242 * forget about the empty space
243 */
244 if (slotcount < wincnt)
245 slotcount = 0;
246
247 /*
248 * Check for Win95 long filename entry
249 */
250 if (dep->deAttributes == ATTR_WIN95) {
251 if (pmp->pm_flags & MSDOSFSMNT_SHORTNAME)
252 continue;
253
254 chksum = win2unixfn((struct winentry *)dep,
255 chksum,
256 pmp);
257 continue;
258 }
259
260 chksum = winChkName((const u_char *)cnp->cn_nameptr,
261 unlen,
262 chksum,
263 pmp);
264 if (chksum == -2) {
265 chksum = -1;
266 continue;
267 }
268
269 /*
270 * Ignore volume labels (anywhere, not just
271 * the root directory).
272 */
273 if (dep->deAttributes & ATTR_VOLUME) {
274 chksum = -1;
275 continue;
276 }
277
278 /*
279 * Check for a checksum or name match
280 */
281 chksum_ok = (chksum == winChksum(dep->deName));
282 if (!chksum_ok
283 && (!olddos || bcmp(dosfilename, dep->deName, 11))) {
284 chksum = -1;
285 continue;
286 }
287 #ifdef MSDOSFS_DEBUG
288 printf("msdosfs_lookup(): match blkoff %d, diroff %d\n",
289 blkoff, diroff);
290 #endif
291 /*
292 * Remember where this directory
293 * entry came from for whoever did
294 * this lookup.
295 */
296 dp->de_fndoffset = diroff;
297 if (chksum_ok && nameiop == RENAME) {
298 /*
299 * Target had correct long name
300 * directory entries, reuse them
301 * as needed.
302 */
303 dp->de_fndcnt = wincnt - 1;
304 } else {
305 /*
306 * Long name directory entries
307 * not present or corrupt, can only
308 * reuse dos directory entry.
309 */
310 dp->de_fndcnt = 0;
311 }
312
313 goto found;
314 }
315 } /* for (blkoff = 0; .... */
316 /*
317 * Release the buffer holding the directory cluster just
318 * searched.
319 */
320 brelse(bp);
321 } /* for (frcn = 0; ; frcn++) */
322
323 notfound:
324 /*
325 * We hold no disk buffers at this point.
326 */
327
328 /*
329 * Fixup the slot description to point to the place where
330 * we might put the new DOS direntry (putting the Win95
331 * long name entries before that)
332 */
333 if (!slotcount) {
334 slotcount = 1;
335 slotoffset = diroff;
336 }
337 if (wincnt > slotcount)
338 slotoffset += sizeof(struct direntry) * (wincnt - slotcount);
339
340 /*
341 * If we get here we didn't find the entry we were looking for. But
342 * that's ok if we are creating or renaming and are at the end of
343 * the pathname and the directory hasn't been removed.
344 */
345 #ifdef MSDOSFS_DEBUG
346 printf("msdosfs_lookup(): op %d, refcnt %ld\n",
347 nameiop, dp->de_refcnt);
348 printf(" slotcount %d, slotoffset %d\n",
349 slotcount, slotoffset);
350 #endif
351 if ((nameiop == CREATE || nameiop == RENAME) &&
352 (flags & ISLASTCN) && dp->de_refcnt != 0) {
353 /*
354 * Access for write is interpreted as allowing
355 * creation of files in the directory.
356 */
357 error = VOP_ACCESS(vdp, VWRITE, cnp->cn_cred, cnp->cn_thread);
358 if (error)
359 return (error);
360 /*
361 * Return an indication of where the new directory
362 * entry should be put.
363 */
364 dp->de_fndoffset = slotoffset;
365 dp->de_fndcnt = wincnt - 1;
366
367 /*
368 * We return with the directory locked, so that
369 * the parameters we set up above will still be
370 * valid if we actually decide to do a direnter().
371 * We return ni_vp == NULL to indicate that the entry
372 * does not currently exist; we leave a pointer to
373 * the (locked) directory inode in ndp->ni_dvp.
374 * The pathname buffer is saved so that the name
375 * can be obtained later.
376 *
377 * NB - if the directory is unlocked, then this
378 * information cannot be used.
379 */
380 cnp->cn_flags |= SAVENAME;
381 return (EJUSTRETURN);
382 }
383 #if 0
384 /*
385 * Insert name into cache (as non-existent) if appropriate.
386 *
387 * XXX Negative caching is broken for msdosfs because the name
388 * cache doesn't understand peculiarities such as case insensitivity
389 * and 8.3 filenames. Hence, it may not invalidate all negative
390 * entries if a file with this name is later created.
391 */
392 if ((cnp->cn_flags & MAKEENTRY) && nameiop != CREATE)
393 cache_enter(vdp, *vpp, cnp);
394 #endif
395 return (ENOENT);
396
397 found:
398 /*
399 * NOTE: We still have the buffer with matched directory entry at
400 * this point.
401 */
402 isadir = dep->deAttributes & ATTR_DIRECTORY;
403 scn = getushort(dep->deStartCluster);
404 if (FAT32(pmp)) {
405 scn |= getushort(dep->deHighClust) << 16;
406 if (scn == pmp->pm_rootdirblk) {
407 /*
408 * There should actually be 0 here.
409 * Just ignore the error.
410 */
411 scn = MSDOSFSROOT;
412 }
413 }
414
415 if (isadir) {
416 cluster = scn;
417 if (cluster == MSDOSFSROOT)
418 blkoff = MSDOSFSROOT_OFS;
419 else
420 blkoff = 0;
421 } else if (cluster == MSDOSFSROOT)
422 blkoff = diroff;
423
424 /*
425 * Now release buf to allow deget to read the entry again.
426 * Reserving it here and giving it to deget could result
427 * in a deadlock.
428 */
429 brelse(bp);
430 bp = 0;
431
432 foundroot:
433 /*
434 * If we entered at foundroot, then we are looking for the . or ..
435 * entry of the filesystems root directory. isadir and scn were
436 * setup before jumping here. And, bp is already null.
437 */
438 if (FAT32(pmp) && scn == MSDOSFSROOT)
439 scn = pmp->pm_rootdirblk;
440
441 /*
442 * If deleting, and at end of pathname, return
443 * parameters which can be used to remove file.
444 */
445 if (nameiop == DELETE && (flags & ISLASTCN)) {
446 /*
447 * Don't allow deleting the root.
448 */
449 if (blkoff == MSDOSFSROOT_OFS)
450 return EROFS; /* really? XXX */
451
452 /*
453 * Write access to directory required to delete files.
454 */
455 error = VOP_ACCESS(vdp, VWRITE, cnp->cn_cred, cnp->cn_thread);
456 if (error)
457 return (error);
458
459 /*
460 * Return pointer to current entry in dp->i_offset.
461 * Save directory inode pointer in ndp->ni_dvp for dirremove().
462 */
463 if (dp->de_StartCluster == scn && isadir) { /* "." */
464 VREF(vdp);
465 *vpp = vdp;
466 return (0);
467 }
468 error = deget(pmp, cluster, blkoff, &tdp);
469 if (error)
470 return (error);
471 *vpp = DETOV(tdp);
472 return (0);
473 }
474
475 /*
476 * If rewriting (RENAME), return the inode and the
477 * information required to rewrite the present directory
478 * Must get inode of directory entry to verify it's a
479 * regular file, or empty directory.
480 */
481 if (nameiop == RENAME && (flags & ISLASTCN)) {
482 if (blkoff == MSDOSFSROOT_OFS)
483 return EROFS; /* really? XXX */
484
485 error = VOP_ACCESS(vdp, VWRITE, cnp->cn_cred, cnp->cn_thread);
486 if (error)
487 return (error);
488
489 /*
490 * Careful about locking second inode.
491 * This can only occur if the target is ".".
492 */
493 if (dp->de_StartCluster == scn && isadir)
494 return (EISDIR);
495
496 if ((error = deget(pmp, cluster, blkoff, &tdp)) != 0)
497 return (error);
498 *vpp = DETOV(tdp);
499 cnp->cn_flags |= SAVENAME;
500 return (0);
501 }
502
503 /*
504 * Step through the translation in the name. We do not `vput' the
505 * directory because we may need it again if a symbolic link
506 * is relative to the current directory. Instead we save it
507 * unlocked as "pdp". We must get the target inode before unlocking
508 * the directory to insure that the inode will not be removed
509 * before we get it. We prevent deadlock by always fetching
510 * inodes from the root, moving down the directory tree. Thus
511 * when following backward pointers ".." we must unlock the
512 * parent directory before getting the requested directory.
513 * There is a potential race condition here if both the current
514 * and parent directories are removed before the VFS_VGET for the
515 * inode associated with ".." returns. We hope that this occurs
516 * infrequently since we cannot avoid this race condition without
517 * implementing a sophisticated deadlock detection algorithm.
518 * Note also that this simple deadlock detection scheme will not
519 * work if the filesystem has any hard links other than ".."
520 * that point backwards in the directory structure.
521 */
522 pdp = vdp;
523 if (flags & ISDOTDOT) {
524 VOP_UNLOCK(pdp, 0, td);
525 error = deget(pmp, cluster, blkoff, &tdp);
526 vn_lock(pdp, LK_EXCLUSIVE | LK_RETRY, td);
527 if (error)
528 return (error);
529 *vpp = DETOV(tdp);
530 } else if (dp->de_StartCluster == scn && isadir) {
531 VREF(vdp); /* we want ourself, ie "." */
532 *vpp = vdp;
533 } else {
534 if ((error = deget(pmp, cluster, blkoff, &tdp)) != 0)
535 return (error);
536 *vpp = DETOV(tdp);
537 }
538
539 /*
540 * Insert name into cache if appropriate.
541 */
542 if (cnp->cn_flags & MAKEENTRY)
543 cache_enter(vdp, *vpp, cnp);
544 return (0);
545 }
546
547 /*
548 * dep - directory entry to copy into the directory
549 * ddep - directory to add to
550 * depp - return the address of the denode for the created directory entry
551 * if depp != 0
552 * cnp - componentname needed for Win95 long filenames
553 */
554 int
555 createde(dep, ddep, depp, cnp)
556 struct denode *dep;
557 struct denode *ddep;
558 struct denode **depp;
559 struct componentname *cnp;
560 {
561 int error;
562 u_long dirclust, diroffset;
563 struct direntry *ndep;
564 struct msdosfsmount *pmp = ddep->de_pmp;
565 struct buf *bp;
566 daddr_t bn;
567 int blsize;
568
569 #ifdef MSDOSFS_DEBUG
570 printf("createde(dep %p, ddep %p, depp %p, cnp %p)\n",
571 dep, ddep, depp, cnp);
572 #endif
573
574 /*
575 * If no space left in the directory then allocate another cluster
576 * and chain it onto the end of the file. There is one exception
577 * to this. That is, if the root directory has no more space it
578 * can NOT be expanded. extendfile() checks for and fails attempts
579 * to extend the root directory. We just return an error in that
580 * case.
581 */
582 if (ddep->de_fndoffset >= ddep->de_FileSize) {
583 diroffset = ddep->de_fndoffset + sizeof(struct direntry)
584 - ddep->de_FileSize;
585 dirclust = de_clcount(pmp, diroffset);
586 error = extendfile(ddep, dirclust, 0, 0, DE_CLEAR);
587 if (error) {
588 (void)detrunc(ddep, ddep->de_FileSize, 0, NOCRED, NULL);
589 return error;
590 }
591
592 /*
593 * Update the size of the directory
594 */
595 ddep->de_FileSize += de_cn2off(pmp, dirclust);
596 }
597
598 /*
599 * We just read in the cluster with space. Copy the new directory
600 * entry in. Then write it to disk. NOTE: DOS directories
601 * do not get smaller as clusters are emptied.
602 */
603 error = pcbmap(ddep, de_cluster(pmp, ddep->de_fndoffset),
604 &bn, &dirclust, &blsize);
605 if (error)
606 return error;
607 diroffset = ddep->de_fndoffset;
608 if (dirclust != MSDOSFSROOT)
609 diroffset &= pmp->pm_crbomask;
610 if ((error = bread(pmp->pm_devvp, bn, blsize, NOCRED, &bp)) != 0) {
611 brelse(bp);
612 return error;
613 }
614 ndep = bptoep(pmp, bp, ddep->de_fndoffset);
615
616 DE_EXTERNALIZE(ndep, dep);
617
618 /*
619 * Now write the Win95 long name
620 */
621 if (ddep->de_fndcnt > 0) {
622 u_int8_t chksum = winChksum(ndep->deName);
623 const u_char *un = (const u_char *)cnp->cn_nameptr;
624 int unlen = cnp->cn_namelen;
625 int cnt = 1;
626
627 while (--ddep->de_fndcnt >= 0) {
628 if (!(ddep->de_fndoffset & pmp->pm_crbomask)) {
629 if ((error = bwrite(bp)) != 0)
630 return error;
631
632 ddep->de_fndoffset -= sizeof(struct direntry);
633 error = pcbmap(ddep,
634 de_cluster(pmp,
635 ddep->de_fndoffset),
636 &bn, 0, &blsize);
637 if (error)
638 return error;
639
640 error = bread(pmp->pm_devvp, bn, blsize,
641 NOCRED, &bp);
642 if (error) {
643 brelse(bp);
644 return error;
645 }
646 ndep = bptoep(pmp, bp, ddep->de_fndoffset);
647 } else {
648 ndep--;
649 ddep->de_fndoffset -= sizeof(struct direntry);
650 }
651 if (!unix2winfn(un, unlen, (struct winentry *)ndep,
652 cnt++, chksum, pmp))
653 break;
654 }
655 }
656
657 if ((error = bwrite(bp)) != 0)
658 return error;
659
660 /*
661 * If they want us to return with the denode gotten.
662 */
663 if (depp) {
664 if (dep->de_Attributes & ATTR_DIRECTORY) {
665 dirclust = dep->de_StartCluster;
666 if (FAT32(pmp) && dirclust == pmp->pm_rootdirblk)
667 dirclust = MSDOSFSROOT;
668 if (dirclust == MSDOSFSROOT)
669 diroffset = MSDOSFSROOT_OFS;
670 else
671 diroffset = 0;
672 }
673 return deget(pmp, dirclust, diroffset, depp);
674 }
675
676 return 0;
677 }
678
679 /*
680 * Be sure a directory is empty except for "." and "..". Return 1 if empty,
681 * return 0 if not empty or error.
682 */
683 int
684 dosdirempty(dep)
685 struct denode *dep;
686 {
687 int blsize;
688 int error;
689 u_long cn;
690 daddr_t bn;
691 struct buf *bp;
692 struct msdosfsmount *pmp = dep->de_pmp;
693 struct direntry *dentp;
694
695 /*
696 * Since the filesize field in directory entries for a directory is
697 * zero, we just have to feel our way through the directory until
698 * we hit end of file.
699 */
700 for (cn = 0;; cn++) {
701 if ((error = pcbmap(dep, cn, &bn, 0, &blsize)) != 0) {
702 if (error == E2BIG)
703 return (1); /* it's empty */
704 return (0);
705 }
706 error = bread(pmp->pm_devvp, bn, blsize, NOCRED, &bp);
707 if (error) {
708 brelse(bp);
709 return (0);
710 }
711 for (dentp = (struct direntry *)bp->b_data;
712 (char *)dentp < bp->b_data + blsize;
713 dentp++) {
714 if (dentp->deName[0] != SLOT_DELETED &&
715 (dentp->deAttributes & ATTR_VOLUME) == 0) {
716 /*
717 * In dos directories an entry whose name
718 * starts with SLOT_EMPTY (0) starts the
719 * beginning of the unused part of the
720 * directory, so we can just return that it
721 * is empty.
722 */
723 if (dentp->deName[0] == SLOT_EMPTY) {
724 brelse(bp);
725 return (1);
726 }
727 /*
728 * Any names other than "." and ".." in a
729 * directory mean it is not empty.
730 */
731 if (bcmp(dentp->deName, ". ", 11) &&
732 bcmp(dentp->deName, ".. ", 11)) {
733 brelse(bp);
734 #ifdef MSDOSFS_DEBUG
735 printf("dosdirempty(): entry found %02x, %02x\n",
736 dentp->deName[0], dentp->deName[1]);
737 #endif
738 return (0); /* not empty */
739 }
740 }
741 }
742 brelse(bp);
743 }
744 /* NOTREACHED */
745 }
746
747 /*
748 * Check to see if the directory described by target is in some
749 * subdirectory of source. This prevents something like the following from
750 * succeeding and leaving a bunch or files and directories orphaned. mv
751 * /a/b/c /a/b/c/d/e/f Where c and f are directories.
752 *
753 * source - the inode for /a/b/c
754 * target - the inode for /a/b/c/d/e/f
755 *
756 * Returns 0 if target is NOT a subdirectory of source.
757 * Otherwise returns a non-zero error number.
758 * The target inode is always unlocked on return.
759 */
760 int
761 doscheckpath(source, target)
762 struct denode *source;
763 struct denode *target;
764 {
765 daddr_t scn;
766 struct msdosfsmount *pmp;
767 struct direntry *ep;
768 struct denode *dep;
769 struct buf *bp = NULL;
770 int error = 0;
771
772 dep = target;
773 if ((target->de_Attributes & ATTR_DIRECTORY) == 0 ||
774 (source->de_Attributes & ATTR_DIRECTORY) == 0) {
775 error = ENOTDIR;
776 goto out;
777 }
778 if (dep->de_StartCluster == source->de_StartCluster) {
779 error = EEXIST;
780 goto out;
781 }
782 if (dep->de_StartCluster == MSDOSFSROOT)
783 goto out;
784 pmp = dep->de_pmp;
785 #ifdef DIAGNOSTIC
786 if (pmp != source->de_pmp)
787 panic("doscheckpath: source and target on different filesystems");
788 #endif
789 if (FAT32(pmp) && dep->de_StartCluster == pmp->pm_rootdirblk)
790 goto out;
791
792 for (;;) {
793 if ((dep->de_Attributes & ATTR_DIRECTORY) == 0) {
794 error = ENOTDIR;
795 break;
796 }
797 scn = dep->de_StartCluster;
798 error = bread(pmp->pm_devvp, cntobn(pmp, scn),
799 pmp->pm_bpcluster, NOCRED, &bp);
800 if (error)
801 break;
802
803 ep = (struct direntry *) bp->b_data + 1;
804 if ((ep->deAttributes & ATTR_DIRECTORY) == 0 ||
805 bcmp(ep->deName, ".. ", 11) != 0) {
806 error = ENOTDIR;
807 break;
808 }
809 scn = getushort(ep->deStartCluster);
810 if (FAT32(pmp))
811 scn |= getushort(ep->deHighClust) << 16;
812
813 if (scn == source->de_StartCluster) {
814 error = EINVAL;
815 break;
816 }
817 if (scn == MSDOSFSROOT)
818 break;
819 if (FAT32(pmp) && scn == pmp->pm_rootdirblk) {
820 /*
821 * scn should be 0 in this case,
822 * but we silently ignore the error.
823 */
824 break;
825 }
826
827 vput(DETOV(dep));
828 brelse(bp);
829 bp = NULL;
830 /* NOTE: deget() clears dep on error */
831 if ((error = deget(pmp, scn, 0, &dep)) != 0)
832 break;
833 }
834 out:;
835 if (bp)
836 brelse(bp);
837 if (error == ENOTDIR)
838 printf("doscheckpath(): .. not a directory?\n");
839 if (dep != NULL)
840 vput(DETOV(dep));
841 return (error);
842 }
843
844 /*
845 * Read in the disk block containing the directory entry (dirclu, dirofs)
846 * and return the address of the buf header, and the address of the
847 * directory entry within the block.
848 */
849 int
850 readep(pmp, dirclust, diroffset, bpp, epp)
851 struct msdosfsmount *pmp;
852 u_long dirclust, diroffset;
853 struct buf **bpp;
854 struct direntry **epp;
855 {
856 int error;
857 daddr_t bn;
858 int blsize;
859
860 blsize = pmp->pm_bpcluster;
861 if (dirclust == MSDOSFSROOT
862 && de_blk(pmp, diroffset + blsize) > pmp->pm_rootdirsize)
863 blsize = de_bn2off(pmp, pmp->pm_rootdirsize) & pmp->pm_crbomask;
864 bn = detobn(pmp, dirclust, diroffset);
865 if ((error = bread(pmp->pm_devvp, bn, blsize, NOCRED, bpp)) != 0) {
866 brelse(*bpp);
867 *bpp = NULL;
868 return (error);
869 }
870 if (epp)
871 *epp = bptoep(pmp, *bpp, diroffset);
872 return (0);
873 }
874
875 /*
876 * Read in the disk block containing the directory entry dep came from and
877 * return the address of the buf header, and the address of the directory
878 * entry within the block.
879 */
880 int
881 readde(dep, bpp, epp)
882 struct denode *dep;
883 struct buf **bpp;
884 struct direntry **epp;
885 {
886
887 return (readep(dep->de_pmp, dep->de_dirclust, dep->de_diroffset,
888 bpp, epp));
889 }
890
891 /*
892 * Remove a directory entry. At this point the file represented by the
893 * directory entry to be removed is still full length until noone has it
894 * open. When the file no longer being used msdosfs_inactive() is called
895 * and will truncate the file to 0 length. When the vnode containing the
896 * denode is needed for some other purpose by VFS it will call
897 * msdosfs_reclaim() which will remove the denode from the denode cache.
898 */
899 int
900 removede(pdep, dep)
901 struct denode *pdep; /* directory where the entry is removed */
902 struct denode *dep; /* file to be removed */
903 {
904 int error;
905 struct direntry *ep;
906 struct buf *bp;
907 daddr_t bn;
908 int blsize;
909 struct msdosfsmount *pmp = pdep->de_pmp;
910 u_long offset = pdep->de_fndoffset;
911
912 #ifdef MSDOSFS_DEBUG
913 printf("removede(): filename %s, dep %p, offset %08lx\n",
914 dep->de_Name, dep, offset);
915 #endif
916
917 dep->de_refcnt--;
918 offset += sizeof(struct direntry);
919 do {
920 offset -= sizeof(struct direntry);
921 error = pcbmap(pdep, de_cluster(pmp, offset), &bn, 0, &blsize);
922 if (error)
923 return error;
924 error = bread(pmp->pm_devvp, bn, blsize, NOCRED, &bp);
925 if (error) {
926 brelse(bp);
927 return error;
928 }
929 ep = bptoep(pmp, bp, offset);
930 /*
931 * Check whether, if we came here the second time, i.e.
932 * when underflowing into the previous block, the last
933 * entry in this block is a longfilename entry, too.
934 */
935 if (ep->deAttributes != ATTR_WIN95
936 && offset != pdep->de_fndoffset) {
937 brelse(bp);
938 break;
939 }
940 offset += sizeof(struct direntry);
941 while (1) {
942 /*
943 * We are a bit agressive here in that we delete any Win95
944 * entries preceding this entry, not just the ones we "own".
945 * Since these presumably aren't valid anyway,
946 * there should be no harm.
947 */
948 offset -= sizeof(struct direntry);
949 ep--->deName[0] = SLOT_DELETED;
950 if ((pmp->pm_flags & MSDOSFSMNT_NOWIN95)
951 || !(offset & pmp->pm_crbomask)
952 || ep->deAttributes != ATTR_WIN95)
953 break;
954 }
955 if ((error = bwrite(bp)) != 0)
956 return error;
957 } while (!(pmp->pm_flags & MSDOSFSMNT_NOWIN95)
958 && !(offset & pmp->pm_crbomask)
959 && offset);
960 return 0;
961 }
962
963 /*
964 * Create a unique DOS name in dvp
965 */
966 int
967 uniqdosname(dep, cnp, cp)
968 struct denode *dep;
969 struct componentname *cnp;
970 u_char *cp;
971 {
972 struct msdosfsmount *pmp = dep->de_pmp;
973 struct direntry *dentp;
974 int gen;
975 int blsize;
976 u_long cn;
977 daddr_t bn;
978 struct buf *bp;
979 int error;
980
981 if (pmp->pm_flags & MSDOSFSMNT_SHORTNAME)
982 return (unix2dosfn((const u_char *)cnp->cn_nameptr, cp,
983 cnp->cn_namelen, 0, pmp) ? 0 : EINVAL);
984
985 for (gen = 1;; gen++) {
986 /*
987 * Generate DOS name with generation number
988 */
989 if (!unix2dosfn((const u_char *)cnp->cn_nameptr, cp,
990 cnp->cn_namelen, gen, pmp))
991 return gen == 1 ? EINVAL : EEXIST;
992
993 /*
994 * Now look for a dir entry with this exact name
995 */
996 for (cn = error = 0; !error; cn++) {
997 if ((error = pcbmap(dep, cn, &bn, 0, &blsize)) != 0) {
998 if (error == E2BIG) /* EOF reached and not found */
999 return 0;
1000 return error;
1001 }
1002 error = bread(pmp->pm_devvp, bn, blsize, NOCRED, &bp);
1003 if (error) {
1004 brelse(bp);
1005 return error;
1006 }
1007 for (dentp = (struct direntry *)bp->b_data;
1008 (char *)dentp < bp->b_data + blsize;
1009 dentp++) {
1010 if (dentp->deName[0] == SLOT_EMPTY) {
1011 /*
1012 * Last used entry and not found
1013 */
1014 brelse(bp);
1015 return 0;
1016 }
1017 /*
1018 * Ignore volume labels and Win95 entries
1019 */
1020 if (dentp->deAttributes & ATTR_VOLUME)
1021 continue;
1022 if (!bcmp(dentp->deName, cp, 11)) {
1023 error = EEXIST;
1024 break;
1025 }
1026 }
1027 brelse(bp);
1028 }
1029 }
1030 }
1031
1032 /*
1033 * Find any Win'95 long filename entry in directory dep
1034 */
1035 int
1036 findwin95(dep)
1037 struct denode *dep;
1038 {
1039 struct msdosfsmount *pmp = dep->de_pmp;
1040 struct direntry *dentp;
1041 int blsize, win95;
1042 u_long cn;
1043 daddr_t bn;
1044 struct buf *bp;
1045
1046 win95 = 1;
1047 /*
1048 * Read through the directory looking for Win'95 entries
1049 * Note: Error currently handled just as EOF XXX
1050 */
1051 for (cn = 0;; cn++) {
1052 if (pcbmap(dep, cn, &bn, 0, &blsize))
1053 return (win95);
1054 if (bread(pmp->pm_devvp, bn, blsize, NOCRED, &bp)) {
1055 brelse(bp);
1056 return (win95);
1057 }
1058 for (dentp = (struct direntry *)bp->b_data;
1059 (char *)dentp < bp->b_data + blsize;
1060 dentp++) {
1061 if (dentp->deName[0] == SLOT_EMPTY) {
1062 /*
1063 * Last used entry and not found
1064 */
1065 brelse(bp);
1066 return (win95);
1067 }
1068 if (dentp->deName[0] == SLOT_DELETED) {
1069 /*
1070 * Ignore deleted files
1071 * Note: might be an indication of Win'95 anyway XXX
1072 */
1073 continue;
1074 }
1075 if (dentp->deAttributes == ATTR_WIN95) {
1076 brelse(bp);
1077 return 1;
1078 }
1079 win95 = 0;
1080 }
1081 brelse(bp);
1082 }
1083 }
Cache object: 6937df2b80d2c4718e32ddc6d321ad3a
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