1 /* $FreeBSD$ */
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 lockparent;
94 int wantparent;
95 int slotcount;
96 int slotoffset = 0;
97 int frcn;
98 u_long cluster;
99 int blkoff;
100 int diroff;
101 int blsize;
102 int isadir; /* ~0 if found direntry is a directory */
103 u_long scn; /* starting cluster number */
104 struct vnode *pdp;
105 struct denode *dp;
106 struct denode *tdp;
107 struct msdosfsmount *pmp;
108 struct buf *bp = 0;
109 struct direntry *dep = NULL;
110 u_char dosfilename[12];
111 int flags = cnp->cn_flags;
112 int nameiop = cnp->cn_nameiop;
113 struct thread *td = cnp->cn_thread;
114 int unlen;
115
116 int wincnt = 1;
117 int chksum = -1, chksum_ok;
118 int olddos = 1;
119 cnp->cn_flags &= ~PDIRUNLOCK;
120
121 #ifdef MSDOSFS_DEBUG
122 printf("msdosfs_lookup(): looking for %s\n", cnp->cn_nameptr);
123 #endif
124 dp = VTODE(vdp);
125 pmp = dp->de_pmp;
126 *vpp = NULL;
127 lockparent = flags & LOCKPARENT;
128 wantparent = flags & (LOCKPARENT | WANTPARENT);
129 #ifdef MSDOSFS_DEBUG
130 printf("msdosfs_lookup(): vdp %p, dp %p, Attr %02x\n",
131 vdp, dp, dp->de_Attributes);
132 #endif
133
134 /*
135 * If they are going after the . or .. entry in the root directory,
136 * they won't find it. DOS filesystems don't have them in the root
137 * directory. So, we fake it. deget() is in on this scam too.
138 */
139 if ((vdp->v_vflag & VV_ROOT) && cnp->cn_nameptr[0] == '.' &&
140 (cnp->cn_namelen == 1 ||
141 (cnp->cn_namelen == 2 && cnp->cn_nameptr[1] == '.'))) {
142 isadir = ATTR_DIRECTORY;
143 scn = MSDOSFSROOT;
144 #ifdef MSDOSFS_DEBUG
145 printf("msdosfs_lookup(): looking for . or .. in root directory\n");
146 #endif
147 cluster = MSDOSFSROOT;
148 blkoff = MSDOSFSROOT_OFS;
149 goto foundroot;
150 }
151
152 switch (unix2dosfn((const u_char *)cnp->cn_nameptr, dosfilename,
153 cnp->cn_namelen, 0, pmp)) {
154 case 0:
155 return (EINVAL);
156 case 1:
157 break;
158 case 2:
159 wincnt = winSlotCnt((const u_char *)cnp->cn_nameptr,
160 cnp->cn_namelen, pmp) + 1;
161 break;
162 case 3:
163 olddos = 0;
164 wincnt = winSlotCnt((const u_char *)cnp->cn_nameptr,
165 cnp->cn_namelen, pmp) + 1;
166 break;
167 }
168 if (pmp->pm_flags & MSDOSFSMNT_SHORTNAME) {
169 wincnt = 1;
170 olddos = 1;
171 }
172 unlen = winLenFixup(cnp->cn_nameptr, cnp->cn_namelen);
173
174 /*
175 * Suppress search for slots unless creating
176 * file and at end of pathname, in which case
177 * we watch for a place to put the new file in
178 * case it doesn't already exist.
179 */
180 slotcount = wincnt;
181 if ((nameiop == CREATE || nameiop == RENAME) &&
182 (flags & ISLASTCN))
183 slotcount = 0;
184
185 #ifdef MSDOSFS_DEBUG
186 printf("msdosfs_lookup(): dos version of filename %s, length %ld\n",
187 dosfilename, cnp->cn_namelen);
188 #endif
189 /*
190 * Search the directory pointed at by vdp for the name pointed at
191 * by cnp->cn_nameptr.
192 */
193 tdp = NULL;
194 mbnambuf_init();
195 /*
196 * The outer loop ranges over the clusters that make up the
197 * directory. Note that the root directory is different from all
198 * other directories. It has a fixed number of blocks that are not
199 * part of the pool of allocatable clusters. So, we treat it a
200 * little differently. The root directory starts at "cluster" 0.
201 */
202 diroff = 0;
203 for (frcn = 0;; frcn++) {
204 error = pcbmap(dp, frcn, &bn, &cluster, &blsize);
205 if (error) {
206 if (error == E2BIG)
207 break;
208 return (error);
209 }
210 error = bread(pmp->pm_devvp, bn, blsize, NOCRED, &bp);
211 if (error) {
212 brelse(bp);
213 return (error);
214 }
215 for (blkoff = 0; blkoff < blsize;
216 blkoff += sizeof(struct direntry),
217 diroff += sizeof(struct direntry)) {
218 dep = (struct direntry *)(bp->b_data + blkoff);
219 /*
220 * If the slot is empty and we are still looking
221 * for an empty then remember this one. If the
222 * slot is not empty then check to see if it
223 * matches what we are looking for. If the slot
224 * has never been filled with anything, then the
225 * remainder of the directory has never been used,
226 * so there is no point in searching it.
227 */
228 if (dep->deName[0] == SLOT_EMPTY ||
229 dep->deName[0] == SLOT_DELETED) {
230 /*
231 * Drop memory of previous long matches
232 */
233 chksum = -1;
234 mbnambuf_init();
235
236 if (slotcount < wincnt) {
237 slotcount++;
238 slotoffset = diroff;
239 }
240 if (dep->deName[0] == SLOT_EMPTY) {
241 brelse(bp);
242 goto notfound;
243 }
244 } else {
245 /*
246 * If there wasn't enough space for our winentries,
247 * forget about the empty space
248 */
249 if (slotcount < wincnt)
250 slotcount = 0;
251
252 /*
253 * Check for Win95 long filename entry
254 */
255 if (dep->deAttributes == ATTR_WIN95) {
256 if (pmp->pm_flags & MSDOSFSMNT_SHORTNAME)
257 continue;
258
259 chksum = win2unixfn((struct winentry *)dep,
260 chksum,
261 pmp);
262 continue;
263 }
264
265 chksum = winChkName((const u_char *)cnp->cn_nameptr,
266 unlen,
267 chksum,
268 pmp);
269 if (chksum == -2) {
270 chksum = -1;
271 continue;
272 }
273
274 /*
275 * Ignore volume labels (anywhere, not just
276 * the root directory).
277 */
278 if (dep->deAttributes & ATTR_VOLUME) {
279 chksum = -1;
280 continue;
281 }
282
283 /*
284 * Check for a checksum or name match
285 */
286 chksum_ok = (chksum == winChksum(dep->deName));
287 if (!chksum_ok
288 && (!olddos || bcmp(dosfilename, dep->deName, 11))) {
289 chksum = -1;
290 continue;
291 }
292 #ifdef MSDOSFS_DEBUG
293 printf("msdosfs_lookup(): match blkoff %d, diroff %d\n",
294 blkoff, diroff);
295 #endif
296 /*
297 * Remember where this directory
298 * entry came from for whoever did
299 * this lookup.
300 */
301 dp->de_fndoffset = diroff;
302 if (chksum_ok && nameiop == RENAME) {
303 /*
304 * Target had correct long name
305 * directory entries, reuse them
306 * as needed.
307 */
308 dp->de_fndcnt = wincnt - 1;
309 } else {
310 /*
311 * Long name directory entries
312 * not present or corrupt, can only
313 * reuse dos directory entry.
314 */
315 dp->de_fndcnt = 0;
316 }
317
318 goto found;
319 }
320 } /* for (blkoff = 0; .... */
321 /*
322 * Release the buffer holding the directory cluster just
323 * searched.
324 */
325 brelse(bp);
326 } /* for (frcn = 0; ; frcn++) */
327
328 notfound:
329 /*
330 * We hold no disk buffers at this point.
331 */
332
333 /*
334 * Fixup the slot description to point to the place where
335 * we might put the new DOS direntry (putting the Win95
336 * long name entries before that)
337 */
338 if (!slotcount) {
339 slotcount = 1;
340 slotoffset = diroff;
341 }
342 if (wincnt > slotcount)
343 slotoffset += sizeof(struct direntry) * (wincnt - slotcount);
344
345 /*
346 * If we get here we didn't find the entry we were looking for. But
347 * that's ok if we are creating or renaming and are at the end of
348 * the pathname and the directory hasn't been removed.
349 */
350 #ifdef MSDOSFS_DEBUG
351 printf("msdosfs_lookup(): op %d, refcnt %ld\n",
352 nameiop, dp->de_refcnt);
353 printf(" slotcount %d, slotoffset %d\n",
354 slotcount, slotoffset);
355 #endif
356 if ((nameiop == CREATE || nameiop == RENAME) &&
357 (flags & ISLASTCN) && dp->de_refcnt != 0) {
358 /*
359 * Access for write is interpreted as allowing
360 * creation of files in the directory.
361 */
362 error = VOP_ACCESS(vdp, VWRITE, cnp->cn_cred, cnp->cn_thread);
363 if (error)
364 return (error);
365 /*
366 * Return an indication of where the new directory
367 * entry should be put.
368 */
369 dp->de_fndoffset = slotoffset;
370 dp->de_fndcnt = wincnt - 1;
371
372 /*
373 * We return with the directory locked, so that
374 * the parameters we set up above will still be
375 * valid if we actually decide to do a direnter().
376 * We return ni_vp == NULL to indicate that the entry
377 * does not currently exist; we leave a pointer to
378 * the (locked) directory inode in ndp->ni_dvp.
379 * The pathname buffer is saved so that the name
380 * can be obtained later.
381 *
382 * NB - if the directory is unlocked, then this
383 * information cannot be used.
384 */
385 cnp->cn_flags |= SAVENAME;
386 if (!lockparent) {
387 VOP_UNLOCK(vdp, 0, td);
388 cnp->cn_flags |= PDIRUNLOCK;
389 }
390 return (EJUSTRETURN);
391 }
392 /*
393 * Insert name into cache (as non-existent) if appropriate.
394 */
395 if ((cnp->cn_flags & MAKEENTRY) && nameiop != CREATE)
396 cache_enter(vdp, *vpp, cnp);
397 return (ENOENT);
398
399 found:
400 /*
401 * NOTE: We still have the buffer with matched directory entry at
402 * this point.
403 */
404 isadir = dep->deAttributes & ATTR_DIRECTORY;
405 scn = getushort(dep->deStartCluster);
406 if (FAT32(pmp)) {
407 scn |= getushort(dep->deHighClust) << 16;
408 if (scn == pmp->pm_rootdirblk) {
409 /*
410 * There should actually be 0 here.
411 * Just ignore the error.
412 */
413 scn = MSDOSFSROOT;
414 }
415 }
416
417 if (isadir) {
418 cluster = scn;
419 if (cluster == MSDOSFSROOT)
420 blkoff = MSDOSFSROOT_OFS;
421 else
422 blkoff = 0;
423 } else if (cluster == MSDOSFSROOT)
424 blkoff = diroff;
425
426 /*
427 * Now release buf to allow deget to read the entry again.
428 * Reserving it here and giving it to deget could result
429 * in a deadlock.
430 */
431 brelse(bp);
432 bp = 0;
433
434 foundroot:
435 /*
436 * If we entered at foundroot, then we are looking for the . or ..
437 * entry of the filesystems root directory. isadir and scn were
438 * setup before jumping here. And, bp is already null.
439 */
440 if (FAT32(pmp) && scn == MSDOSFSROOT)
441 scn = pmp->pm_rootdirblk;
442
443 /*
444 * If deleting, and at end of pathname, return
445 * parameters which can be used to remove file.
446 * If the wantparent flag isn't set, we return only
447 * the directory (in ndp->ni_dvp), otherwise we go
448 * on and lock the inode, being careful with ".".
449 */
450 if (nameiop == DELETE && (flags & ISLASTCN)) {
451 /*
452 * Don't allow deleting the root.
453 */
454 if (blkoff == MSDOSFSROOT_OFS)
455 return EROFS; /* really? XXX */
456
457 /*
458 * Write access to directory required to delete files.
459 */
460 error = VOP_ACCESS(vdp, VWRITE, cnp->cn_cred, cnp->cn_thread);
461 if (error)
462 return (error);
463
464 /*
465 * Return pointer to current entry in dp->i_offset.
466 * Save directory inode pointer in ndp->ni_dvp for dirremove().
467 */
468 if (dp->de_StartCluster == scn && isadir) { /* "." */
469 VREF(vdp);
470 *vpp = vdp;
471 return (0);
472 }
473 error = deget(pmp, cluster, blkoff, &tdp);
474 if (error)
475 return (error);
476 *vpp = DETOV(tdp);
477 if (!lockparent) {
478 VOP_UNLOCK(vdp, 0, td);
479 cnp->cn_flags |= PDIRUNLOCK;
480 }
481 return (0);
482 }
483
484 /*
485 * If rewriting (RENAME), return the inode and the
486 * information required to rewrite the present directory
487 * Must get inode of directory entry to verify it's a
488 * regular file, or empty directory.
489 */
490 if (nameiop == RENAME && wantparent &&
491 (flags & ISLASTCN)) {
492 if (blkoff == MSDOSFSROOT_OFS)
493 return EROFS; /* really? XXX */
494
495 error = VOP_ACCESS(vdp, VWRITE, cnp->cn_cred, cnp->cn_thread);
496 if (error)
497 return (error);
498
499 /*
500 * Careful about locking second inode.
501 * This can only occur if the target is ".".
502 */
503 if (dp->de_StartCluster == scn && isadir)
504 return (EISDIR);
505
506 if ((error = deget(pmp, cluster, blkoff, &tdp)) != 0)
507 return (error);
508 *vpp = DETOV(tdp);
509 cnp->cn_flags |= SAVENAME;
510 if (!lockparent) {
511 VOP_UNLOCK(vdp, 0, td);
512 cnp->cn_flags |= PDIRUNLOCK;
513 }
514 return (0);
515 }
516
517 /*
518 * Step through the translation in the name. We do not `vput' the
519 * directory because we may need it again if a symbolic link
520 * is relative to the current directory. Instead we save it
521 * unlocked as "pdp". We must get the target inode before unlocking
522 * the directory to insure that the inode will not be removed
523 * before we get it. We prevent deadlock by always fetching
524 * inodes from the root, moving down the directory tree. Thus
525 * when following backward pointers ".." we must unlock the
526 * parent directory before getting the requested directory.
527 * There is a potential race condition here if both the current
528 * and parent directories are removed before the VFS_VGET for the
529 * inode associated with ".." returns. We hope that this occurs
530 * infrequently since we cannot avoid this race condition without
531 * implementing a sophisticated deadlock detection algorithm.
532 * Note also that this simple deadlock detection scheme will not
533 * work if the filesystem has any hard links other than ".."
534 * that point backwards in the directory structure.
535 */
536 pdp = vdp;
537 if (flags & ISDOTDOT) {
538 VOP_UNLOCK(pdp, 0, td);
539 cnp->cn_flags |= PDIRUNLOCK;
540 error = deget(pmp, cluster, blkoff, &tdp);
541 if (error) {
542 vn_lock(pdp, LK_EXCLUSIVE | LK_RETRY, td);
543 cnp->cn_flags &= ~PDIRUNLOCK;
544 return (error);
545 }
546 if (lockparent && (flags & ISLASTCN)) {
547 error = vn_lock(pdp, LK_EXCLUSIVE, td);
548 if (error) {
549 vput(DETOV(tdp));
550 return (error);
551 }
552 cnp->cn_flags &= ~PDIRUNLOCK;
553 }
554 *vpp = DETOV(tdp);
555 } else if (dp->de_StartCluster == scn && isadir) {
556 VREF(vdp); /* we want ourself, ie "." */
557 *vpp = vdp;
558 } else {
559 if ((error = deget(pmp, cluster, blkoff, &tdp)) != 0)
560 return (error);
561 if (!lockparent || !(flags & ISLASTCN)) {
562 VOP_UNLOCK(pdp, 0, td);
563 cnp->cn_flags |= PDIRUNLOCK;
564 }
565 *vpp = DETOV(tdp);
566 }
567
568 /*
569 * Insert name into cache if appropriate.
570 */
571 if (cnp->cn_flags & MAKEENTRY)
572 cache_enter(vdp, *vpp, cnp);
573 return (0);
574 }
575
576 /*
577 * dep - directory entry to copy into the directory
578 * ddep - directory to add to
579 * depp - return the address of the denode for the created directory entry
580 * if depp != 0
581 * cnp - componentname needed for Win95 long filenames
582 */
583 int
584 createde(dep, ddep, depp, cnp)
585 struct denode *dep;
586 struct denode *ddep;
587 struct denode **depp;
588 struct componentname *cnp;
589 {
590 int error;
591 u_long dirclust, diroffset;
592 struct direntry *ndep;
593 struct msdosfsmount *pmp = ddep->de_pmp;
594 struct buf *bp;
595 daddr_t bn;
596 int blsize;
597
598 #ifdef MSDOSFS_DEBUG
599 printf("createde(dep %p, ddep %p, depp %p, cnp %p)\n",
600 dep, ddep, depp, cnp);
601 #endif
602
603 /*
604 * If no space left in the directory then allocate another cluster
605 * and chain it onto the end of the file. There is one exception
606 * to this. That is, if the root directory has no more space it
607 * can NOT be expanded. extendfile() checks for and fails attempts
608 * to extend the root directory. We just return an error in that
609 * case.
610 */
611 if (ddep->de_fndoffset >= ddep->de_FileSize) {
612 diroffset = ddep->de_fndoffset + sizeof(struct direntry)
613 - ddep->de_FileSize;
614 dirclust = de_clcount(pmp, diroffset);
615 error = extendfile(ddep, dirclust, 0, 0, DE_CLEAR);
616 if (error) {
617 (void)detrunc(ddep, ddep->de_FileSize, 0, NOCRED, NULL);
618 return error;
619 }
620
621 /*
622 * Update the size of the directory
623 */
624 ddep->de_FileSize += de_cn2off(pmp, dirclust);
625 }
626
627 /*
628 * We just read in the cluster with space. Copy the new directory
629 * entry in. Then write it to disk. NOTE: DOS directories
630 * do not get smaller as clusters are emptied.
631 */
632 error = pcbmap(ddep, de_cluster(pmp, ddep->de_fndoffset),
633 &bn, &dirclust, &blsize);
634 if (error)
635 return error;
636 diroffset = ddep->de_fndoffset;
637 if (dirclust != MSDOSFSROOT)
638 diroffset &= pmp->pm_crbomask;
639 if ((error = bread(pmp->pm_devvp, bn, blsize, NOCRED, &bp)) != 0) {
640 brelse(bp);
641 return error;
642 }
643 ndep = bptoep(pmp, bp, ddep->de_fndoffset);
644
645 DE_EXTERNALIZE(ndep, dep);
646
647 /*
648 * Now write the Win95 long name
649 */
650 if (ddep->de_fndcnt > 0) {
651 u_int8_t chksum = winChksum(ndep->deName);
652 const u_char *un = (const u_char *)cnp->cn_nameptr;
653 int unlen = cnp->cn_namelen;
654 int cnt = 1;
655
656 while (--ddep->de_fndcnt >= 0) {
657 if (!(ddep->de_fndoffset & pmp->pm_crbomask)) {
658 if ((error = bwrite(bp)) != 0)
659 return error;
660
661 ddep->de_fndoffset -= sizeof(struct direntry);
662 error = pcbmap(ddep,
663 de_cluster(pmp,
664 ddep->de_fndoffset),
665 &bn, 0, &blsize);
666 if (error)
667 return error;
668
669 error = bread(pmp->pm_devvp, bn, blsize,
670 NOCRED, &bp);
671 if (error) {
672 brelse(bp);
673 return error;
674 }
675 ndep = bptoep(pmp, bp, ddep->de_fndoffset);
676 } else {
677 ndep--;
678 ddep->de_fndoffset -= sizeof(struct direntry);
679 }
680 if (!unix2winfn(un, unlen, (struct winentry *)ndep,
681 cnt++, chksum, pmp))
682 break;
683 }
684 }
685
686 if ((error = bwrite(bp)) != 0)
687 return error;
688
689 /*
690 * If they want us to return with the denode gotten.
691 */
692 if (depp) {
693 if (dep->de_Attributes & ATTR_DIRECTORY) {
694 dirclust = dep->de_StartCluster;
695 if (FAT32(pmp) && dirclust == pmp->pm_rootdirblk)
696 dirclust = MSDOSFSROOT;
697 if (dirclust == MSDOSFSROOT)
698 diroffset = MSDOSFSROOT_OFS;
699 else
700 diroffset = 0;
701 }
702 return deget(pmp, dirclust, diroffset, depp);
703 }
704
705 return 0;
706 }
707
708 /*
709 * Be sure a directory is empty except for "." and "..". Return 1 if empty,
710 * return 0 if not empty or error.
711 */
712 int
713 dosdirempty(dep)
714 struct denode *dep;
715 {
716 int blsize;
717 int error;
718 u_long cn;
719 daddr_t bn;
720 struct buf *bp;
721 struct msdosfsmount *pmp = dep->de_pmp;
722 struct direntry *dentp;
723
724 /*
725 * Since the filesize field in directory entries for a directory is
726 * zero, we just have to feel our way through the directory until
727 * we hit end of file.
728 */
729 for (cn = 0;; cn++) {
730 if ((error = pcbmap(dep, cn, &bn, 0, &blsize)) != 0) {
731 if (error == E2BIG)
732 return (1); /* it's empty */
733 return (0);
734 }
735 error = bread(pmp->pm_devvp, bn, blsize, NOCRED, &bp);
736 if (error) {
737 brelse(bp);
738 return (0);
739 }
740 for (dentp = (struct direntry *)bp->b_data;
741 (char *)dentp < bp->b_data + blsize;
742 dentp++) {
743 if (dentp->deName[0] != SLOT_DELETED &&
744 (dentp->deAttributes & ATTR_VOLUME) == 0) {
745 /*
746 * In dos directories an entry whose name
747 * starts with SLOT_EMPTY (0) starts the
748 * beginning of the unused part of the
749 * directory, so we can just return that it
750 * is empty.
751 */
752 if (dentp->deName[0] == SLOT_EMPTY) {
753 brelse(bp);
754 return (1);
755 }
756 /*
757 * Any names other than "." and ".." in a
758 * directory mean it is not empty.
759 */
760 if (bcmp(dentp->deName, ". ", 11) &&
761 bcmp(dentp->deName, ".. ", 11)) {
762 brelse(bp);
763 #ifdef MSDOSFS_DEBUG
764 printf("dosdirempty(): entry found %02x, %02x\n",
765 dentp->deName[0], dentp->deName[1]);
766 #endif
767 return (0); /* not empty */
768 }
769 }
770 }
771 brelse(bp);
772 }
773 /* NOTREACHED */
774 }
775
776 /*
777 * Check to see if the directory described by target is in some
778 * subdirectory of source. This prevents something like the following from
779 * succeeding and leaving a bunch or files and directories orphaned. mv
780 * /a/b/c /a/b/c/d/e/f Where c and f are directories.
781 *
782 * source - the inode for /a/b/c
783 * target - the inode for /a/b/c/d/e/f
784 *
785 * Returns 0 if target is NOT a subdirectory of source.
786 * Otherwise returns a non-zero error number.
787 * The target inode is always unlocked on return.
788 */
789 int
790 doscheckpath(source, target)
791 struct denode *source;
792 struct denode *target;
793 {
794 daddr_t scn;
795 struct msdosfsmount *pmp;
796 struct direntry *ep;
797 struct denode *dep;
798 struct buf *bp = NULL;
799 int error = 0;
800
801 dep = target;
802 if ((target->de_Attributes & ATTR_DIRECTORY) == 0 ||
803 (source->de_Attributes & ATTR_DIRECTORY) == 0) {
804 error = ENOTDIR;
805 goto out;
806 }
807 if (dep->de_StartCluster == source->de_StartCluster) {
808 error = EEXIST;
809 goto out;
810 }
811 if (dep->de_StartCluster == MSDOSFSROOT)
812 goto out;
813 pmp = dep->de_pmp;
814 #ifdef DIAGNOSTIC
815 if (pmp != source->de_pmp)
816 panic("doscheckpath: source and target on different filesystems");
817 #endif
818 if (FAT32(pmp) && dep->de_StartCluster == pmp->pm_rootdirblk)
819 goto out;
820
821 for (;;) {
822 if ((dep->de_Attributes & ATTR_DIRECTORY) == 0) {
823 error = ENOTDIR;
824 break;
825 }
826 scn = dep->de_StartCluster;
827 error = bread(pmp->pm_devvp, cntobn(pmp, scn),
828 pmp->pm_bpcluster, NOCRED, &bp);
829 if (error)
830 break;
831
832 ep = (struct direntry *) bp->b_data + 1;
833 if ((ep->deAttributes & ATTR_DIRECTORY) == 0 ||
834 bcmp(ep->deName, ".. ", 11) != 0) {
835 error = ENOTDIR;
836 break;
837 }
838 scn = getushort(ep->deStartCluster);
839 if (FAT32(pmp))
840 scn |= getushort(ep->deHighClust) << 16;
841
842 if (scn == source->de_StartCluster) {
843 error = EINVAL;
844 break;
845 }
846 if (scn == MSDOSFSROOT)
847 break;
848 if (FAT32(pmp) && scn == pmp->pm_rootdirblk) {
849 /*
850 * scn should be 0 in this case,
851 * but we silently ignore the error.
852 */
853 break;
854 }
855
856 vput(DETOV(dep));
857 brelse(bp);
858 bp = NULL;
859 /* NOTE: deget() clears dep on error */
860 if ((error = deget(pmp, scn, 0, &dep)) != 0)
861 break;
862 }
863 out:;
864 if (bp)
865 brelse(bp);
866 if (error == ENOTDIR)
867 printf("doscheckpath(): .. not a directory?\n");
868 if (dep != NULL)
869 vput(DETOV(dep));
870 return (error);
871 }
872
873 /*
874 * Read in the disk block containing the directory entry (dirclu, dirofs)
875 * and return the address of the buf header, and the address of the
876 * directory entry within the block.
877 */
878 int
879 readep(pmp, dirclust, diroffset, bpp, epp)
880 struct msdosfsmount *pmp;
881 u_long dirclust, diroffset;
882 struct buf **bpp;
883 struct direntry **epp;
884 {
885 int error;
886 daddr_t bn;
887 int blsize;
888
889 blsize = pmp->pm_bpcluster;
890 if (dirclust == MSDOSFSROOT
891 && de_blk(pmp, diroffset + blsize) > pmp->pm_rootdirsize)
892 blsize = de_bn2off(pmp, pmp->pm_rootdirsize) & pmp->pm_crbomask;
893 bn = detobn(pmp, dirclust, diroffset);
894 if ((error = bread(pmp->pm_devvp, bn, blsize, NOCRED, bpp)) != 0) {
895 brelse(*bpp);
896 *bpp = NULL;
897 return (error);
898 }
899 if (epp)
900 *epp = bptoep(pmp, *bpp, diroffset);
901 return (0);
902 }
903
904 /*
905 * Read in the disk block containing the directory entry dep came from and
906 * return the address of the buf header, and the address of the directory
907 * entry within the block.
908 */
909 int
910 readde(dep, bpp, epp)
911 struct denode *dep;
912 struct buf **bpp;
913 struct direntry **epp;
914 {
915
916 return (readep(dep->de_pmp, dep->de_dirclust, dep->de_diroffset,
917 bpp, epp));
918 }
919
920 /*
921 * Remove a directory entry. At this point the file represented by the
922 * directory entry to be removed is still full length until noone has it
923 * open. When the file no longer being used msdosfs_inactive() is called
924 * and will truncate the file to 0 length. When the vnode containing the
925 * denode is needed for some other purpose by VFS it will call
926 * msdosfs_reclaim() which will remove the denode from the denode cache.
927 */
928 int
929 removede(pdep, dep)
930 struct denode *pdep; /* directory where the entry is removed */
931 struct denode *dep; /* file to be removed */
932 {
933 int error;
934 struct direntry *ep;
935 struct buf *bp;
936 daddr_t bn;
937 int blsize;
938 struct msdosfsmount *pmp = pdep->de_pmp;
939 u_long offset = pdep->de_fndoffset;
940
941 #ifdef MSDOSFS_DEBUG
942 printf("removede(): filename %s, dep %p, offset %08lx\n",
943 dep->de_Name, dep, offset);
944 #endif
945
946 dep->de_refcnt--;
947 offset += sizeof(struct direntry);
948 do {
949 offset -= sizeof(struct direntry);
950 error = pcbmap(pdep, de_cluster(pmp, offset), &bn, 0, &blsize);
951 if (error)
952 return error;
953 error = bread(pmp->pm_devvp, bn, blsize, NOCRED, &bp);
954 if (error) {
955 brelse(bp);
956 return error;
957 }
958 ep = bptoep(pmp, bp, offset);
959 /*
960 * Check whether, if we came here the second time, i.e.
961 * when underflowing into the previous block, the last
962 * entry in this block is a longfilename entry, too.
963 */
964 if (ep->deAttributes != ATTR_WIN95
965 && offset != pdep->de_fndoffset) {
966 brelse(bp);
967 break;
968 }
969 offset += sizeof(struct direntry);
970 while (1) {
971 /*
972 * We are a bit agressive here in that we delete any Win95
973 * entries preceding this entry, not just the ones we "own".
974 * Since these presumably aren't valid anyway,
975 * there should be no harm.
976 */
977 offset -= sizeof(struct direntry);
978 ep--->deName[0] = SLOT_DELETED;
979 if ((pmp->pm_flags & MSDOSFSMNT_NOWIN95)
980 || !(offset & pmp->pm_crbomask)
981 || ep->deAttributes != ATTR_WIN95)
982 break;
983 }
984 if ((error = bwrite(bp)) != 0)
985 return error;
986 } while (!(pmp->pm_flags & MSDOSFSMNT_NOWIN95)
987 && !(offset & pmp->pm_crbomask)
988 && offset);
989 return 0;
990 }
991
992 /*
993 * Create a unique DOS name in dvp
994 */
995 int
996 uniqdosname(dep, cnp, cp)
997 struct denode *dep;
998 struct componentname *cnp;
999 u_char *cp;
1000 {
1001 struct msdosfsmount *pmp = dep->de_pmp;
1002 struct direntry *dentp;
1003 int gen;
1004 int blsize;
1005 u_long cn;
1006 daddr_t bn;
1007 struct buf *bp;
1008 int error;
1009
1010 if (pmp->pm_flags & MSDOSFSMNT_SHORTNAME)
1011 return (unix2dosfn((const u_char *)cnp->cn_nameptr, cp,
1012 cnp->cn_namelen, 0, pmp) ? 0 : EINVAL);
1013
1014 for (gen = 1;; gen++) {
1015 /*
1016 * Generate DOS name with generation number
1017 */
1018 if (!unix2dosfn((const u_char *)cnp->cn_nameptr, cp,
1019 cnp->cn_namelen, gen, pmp))
1020 return gen == 1 ? EINVAL : EEXIST;
1021
1022 /*
1023 * Now look for a dir entry with this exact name
1024 */
1025 for (cn = error = 0; !error; cn++) {
1026 if ((error = pcbmap(dep, cn, &bn, 0, &blsize)) != 0) {
1027 if (error == E2BIG) /* EOF reached and not found */
1028 return 0;
1029 return error;
1030 }
1031 error = bread(pmp->pm_devvp, bn, blsize, NOCRED, &bp);
1032 if (error) {
1033 brelse(bp);
1034 return error;
1035 }
1036 for (dentp = (struct direntry *)bp->b_data;
1037 (char *)dentp < bp->b_data + blsize;
1038 dentp++) {
1039 if (dentp->deName[0] == SLOT_EMPTY) {
1040 /*
1041 * Last used entry and not found
1042 */
1043 brelse(bp);
1044 return 0;
1045 }
1046 /*
1047 * Ignore volume labels and Win95 entries
1048 */
1049 if (dentp->deAttributes & ATTR_VOLUME)
1050 continue;
1051 if (!bcmp(dentp->deName, cp, 11)) {
1052 error = EEXIST;
1053 break;
1054 }
1055 }
1056 brelse(bp);
1057 }
1058 }
1059 }
1060
1061 /*
1062 * Find any Win'95 long filename entry in directory dep
1063 */
1064 int
1065 findwin95(dep)
1066 struct denode *dep;
1067 {
1068 struct msdosfsmount *pmp = dep->de_pmp;
1069 struct direntry *dentp;
1070 int blsize, win95;
1071 u_long cn;
1072 daddr_t bn;
1073 struct buf *bp;
1074
1075 win95 = 1;
1076 /*
1077 * Read through the directory looking for Win'95 entries
1078 * Note: Error currently handled just as EOF XXX
1079 */
1080 for (cn = 0;; cn++) {
1081 if (pcbmap(dep, cn, &bn, 0, &blsize))
1082 return (win95);
1083 if (bread(pmp->pm_devvp, bn, blsize, NOCRED, &bp)) {
1084 brelse(bp);
1085 return (win95);
1086 }
1087 for (dentp = (struct direntry *)bp->b_data;
1088 (char *)dentp < bp->b_data + blsize;
1089 dentp++) {
1090 if (dentp->deName[0] == SLOT_EMPTY) {
1091 /*
1092 * Last used entry and not found
1093 */
1094 brelse(bp);
1095 return (win95);
1096 }
1097 if (dentp->deName[0] == SLOT_DELETED) {
1098 /*
1099 * Ignore deleted files
1100 * Note: might be an indication of Win'95 anyway XXX
1101 */
1102 continue;
1103 }
1104 if (dentp->deAttributes == ATTR_WIN95) {
1105 brelse(bp);
1106 return 1;
1107 }
1108 win95 = 0;
1109 }
1110 brelse(bp);
1111 }
1112 }
Cache object: 2b41401b253810daac96b3cfe680fb54
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