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/namei.h>
53 #include <sys/buf.h>
54 #include <sys/vnode.h>
55 #include <sys/mount.h>
56 #include <sys/systm.h>
57
58 #include <msdosfs/bpb.h>
59 #include <msdosfs/direntry.h>
60 #include <msdosfs/denode.h>
61 #include <msdosfs/msdosfsmount.h>
62 #include <msdosfs/fat.h>
63
64 /*
65 * When we search a directory the blocks containing directory entries are
66 * read and examined. The directory entries contain information that would
67 * normally be in the inode of a unix filesystem. This means that some of
68 * a directory's contents may also be in memory resident denodes (sort of
69 * an inode). This can cause problems if we are searching while some other
70 * process is modifying a directory. To prevent one process from accessing
71 * incompletely modified directory information we depend upon being the
72 * sole owner of a directory block. bread/brelse provide this service.
73 * This being the case, when a process modifies a directory it must first
74 * acquire the disk block that contains the directory entry to be modified.
75 * Then update the disk block and the denode, and then write the disk block
76 * out to disk. This way disk blocks containing directory entries and in
77 * memory denode's will be in synch.
78 */
79 int
80 msdosfs_lookup(ap)
81 struct vop_cachedlookup_args /* {
82 struct vnode *a_dvp;
83 struct vnode **a_vpp;
84 struct componentname *a_cnp;
85 } */ *ap;
86 {
87 struct vnode *vdp = ap->a_dvp;
88 struct vnode **vpp = ap->a_vpp;
89 struct componentname *cnp = ap->a_cnp;
90 daddr_t bn;
91 int error;
92 int lockparent;
93 int wantparent;
94 int slotcount;
95 int slotoffset = 0;
96 int frcn;
97 u_long cluster;
98 int blkoff;
99 int diroff;
100 int blsize;
101 int isadir; /* ~0 if found direntry is a directory */
102 u_long scn; /* starting cluster number */
103 struct vnode *pdp;
104 struct denode *dp;
105 struct denode *tdp;
106 struct msdosfsmount *pmp;
107 struct buf *bp = 0;
108 struct direntry *dep = NULL;
109 u_char dosfilename[12];
110 int flags = cnp->cn_flags;
111 int nameiop = cnp->cn_nameiop;
112 struct proc *p = cnp->cn_proc;
113 int unlen;
114
115 int wincnt = 1;
116 int chksum = -1;
117 int olddos = 1;
118
119 #ifdef MSDOSFS_DEBUG
120 printf("msdosfs_lookup(): looking for %s\n", cnp->cn_nameptr);
121 #endif
122 dp = VTODE(vdp);
123 pmp = dp->de_pmp;
124 *vpp = NULL;
125 lockparent = flags & LOCKPARENT;
126 wantparent = flags & (LOCKPARENT | WANTPARENT);
127 #ifdef MSDOSFS_DEBUG
128 printf("msdosfs_lookup(): vdp %p, dp %p, Attr %02x\n",
129 vdp, dp, dp->de_Attributes);
130 #endif
131
132 /*
133 * If they are going after the . or .. entry in the root directory,
134 * they won't find it. DOS filesystems don't have them in the root
135 * directory. So, we fake it. deget() is in on this scam too.
136 */
137 if ((vdp->v_flag & VROOT) && cnp->cn_nameptr[0] == '.' &&
138 (cnp->cn_namelen == 1 ||
139 (cnp->cn_namelen == 2 && cnp->cn_nameptr[1] == '.'))) {
140 isadir = ATTR_DIRECTORY;
141 scn = MSDOSFSROOT;
142 #ifdef MSDOSFS_DEBUG
143 printf("msdosfs_lookup(): looking for . or .. in root directory\n");
144 #endif
145 cluster = MSDOSFSROOT;
146 blkoff = MSDOSFSROOT_OFS;
147 goto foundroot;
148 }
149
150 switch (unix2dosfn((const u_char *)cnp->cn_nameptr, dosfilename,
151 cnp->cn_namelen, 0,
152 pmp->pm_flags & MSDOSFSMNT_U2WTABLE, pmp->pm_u2d,
153 pmp->pm_flags & MSDOSFSMNT_ULTABLE, pmp->pm_lu)) {
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) + 1;
161 break;
162 case 3:
163 olddos = 0;
164 wincnt = winSlotCnt((const u_char *)cnp->cn_nameptr,
165 cnp->cn_namelen) + 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 /*
195 * The outer loop ranges over the clusters that make up the
196 * directory. Note that the root directory is different from all
197 * other directories. It has a fixed number of blocks that are not
198 * part of the pool of allocatable clusters. So, we treat it a
199 * little differently. The root directory starts at "cluster" 0.
200 */
201 diroff = 0;
202 for (frcn = 0;; frcn++) {
203 error = pcbmap(dp, frcn, &bn, &cluster, &blsize);
204 if (error) {
205 if (error == E2BIG)
206 break;
207 return (error);
208 }
209 error = bread(pmp->pm_devvp, bn, blsize, NOCRED, &bp);
210 if (error) {
211 brelse(bp);
212 return (error);
213 }
214 for (blkoff = 0; blkoff < blsize;
215 blkoff += sizeof(struct direntry),
216 diroff += sizeof(struct direntry)) {
217 dep = (struct direntry *)(bp->b_data + blkoff);
218 /*
219 * If the slot is empty and we are still looking
220 * for an empty then remember this one. If the
221 * slot is not empty then check to see if it
222 * matches what we are looking for. If the slot
223 * has never been filled with anything, then the
224 * remainder of the directory has never been used,
225 * so there is no point in searching it.
226 */
227 if (dep->deName[0] == SLOT_EMPTY ||
228 dep->deName[0] == SLOT_DELETED) {
229 /*
230 * Drop memory of previous long matches
231 */
232 chksum = -1;
233
234 if (slotcount < wincnt) {
235 slotcount++;
236 slotoffset = diroff;
237 }
238 if (dep->deName[0] == SLOT_EMPTY) {
239 brelse(bp);
240 goto notfound;
241 }
242 } else {
243 /*
244 * If there wasn't enough space for our winentries,
245 * forget about the empty space
246 */
247 if (slotcount < wincnt)
248 slotcount = 0;
249
250 /*
251 * Check for Win95 long filename entry
252 */
253 if (dep->deAttributes == ATTR_WIN95) {
254 if (pmp->pm_flags & MSDOSFSMNT_SHORTNAME)
255 continue;
256
257 chksum = winChkName((const u_char *)cnp->cn_nameptr,
258 unlen,
259 (struct winentry *)dep,
260 chksum,
261 pmp->pm_flags & MSDOSFSMNT_U2WTABLE,
262 pmp->pm_u2w,
263 pmp->pm_flags & MSDOSFSMNT_ULTABLE,
264 pmp->pm_ul);
265 continue;
266 }
267
268 /*
269 * Ignore volume labels (anywhere, not just
270 * the root directory).
271 */
272 if (dep->deAttributes & ATTR_VOLUME) {
273 chksum = -1;
274 continue;
275 }
276
277 /*
278 * Check for a checksum or name match
279 */
280 if (chksum != winChksum(dep->deName)
281 && (!olddos || bcmp(dosfilename, dep->deName, 11))) {
282 chksum = -1;
283 continue;
284 }
285 #ifdef MSDOSFS_DEBUG
286 printf("msdosfs_lookup(): match blkoff %d, diroff %d\n",
287 blkoff, diroff);
288 #endif
289 /*
290 * Remember where this directory
291 * entry came from for whoever did
292 * this lookup.
293 */
294 dp->de_fndoffset = diroff;
295 dp->de_fndcnt = wincnt - 1;
296
297 goto found;
298 }
299 } /* for (blkoff = 0; .... */
300 /*
301 * Release the buffer holding the directory cluster just
302 * searched.
303 */
304 brelse(bp);
305 } /* for (frcn = 0; ; frcn++) */
306
307 notfound:
308 /*
309 * We hold no disk buffers at this point.
310 */
311
312 /*
313 * Fixup the slot description to point to the place where
314 * we might put the new DOS direntry (putting the Win95
315 * long name entries before that)
316 */
317 if (!slotcount) {
318 slotcount = 1;
319 slotoffset = diroff;
320 }
321 if (wincnt > slotcount)
322 slotoffset += sizeof(struct direntry) * (wincnt - slotcount);
323
324 /*
325 * If we get here we didn't find the entry we were looking for. But
326 * that's ok if we are creating or renaming and are at the end of
327 * the pathname and the directory hasn't been removed.
328 */
329 #ifdef MSDOSFS_DEBUG
330 printf("msdosfs_lookup(): op %d, refcnt %ld\n",
331 nameiop, dp->de_refcnt);
332 printf(" slotcount %d, slotoffset %d\n",
333 slotcount, slotoffset);
334 #endif
335 if ((nameiop == CREATE || nameiop == RENAME) &&
336 (flags & ISLASTCN) && dp->de_refcnt != 0) {
337 /*
338 * Access for write is interpreted as allowing
339 * creation of files in the directory.
340 */
341 error = VOP_ACCESS(vdp, VWRITE, cnp->cn_cred, cnp->cn_proc);
342 if (error)
343 return (error);
344 /*
345 * Return an indication of where the new directory
346 * entry should be put.
347 */
348 dp->de_fndoffset = slotoffset;
349 dp->de_fndcnt = wincnt - 1;
350
351 /*
352 * We return with the directory locked, so that
353 * the parameters we set up above will still be
354 * valid if we actually decide to do a direnter().
355 * We return ni_vp == NULL to indicate that the entry
356 * does not currently exist; we leave a pointer to
357 * the (locked) directory inode in ndp->ni_dvp.
358 * The pathname buffer is saved so that the name
359 * can be obtained later.
360 *
361 * NB - if the directory is unlocked, then this
362 * information cannot be used.
363 */
364 cnp->cn_flags |= SAVENAME;
365 if (!lockparent)
366 VOP_UNLOCK(vdp, 0, p);
367 return (EJUSTRETURN);
368 }
369 /*
370 * Insert name into cache (as non-existent) if appropriate.
371 */
372 if ((cnp->cn_flags & MAKEENTRY) && nameiop != CREATE)
373 cache_enter(vdp, *vpp, cnp);
374 return (ENOENT);
375
376 found:
377 /*
378 * NOTE: We still have the buffer with matched directory entry at
379 * this point.
380 */
381 isadir = dep->deAttributes & ATTR_DIRECTORY;
382 scn = getushort(dep->deStartCluster);
383 if (FAT32(pmp)) {
384 scn |= getushort(dep->deHighClust) << 16;
385 if (scn == pmp->pm_rootdirblk) {
386 /*
387 * There should actually be 0 here.
388 * Just ignore the error.
389 */
390 scn = MSDOSFSROOT;
391 }
392 }
393
394 if (isadir) {
395 cluster = scn;
396 if (cluster == MSDOSFSROOT)
397 blkoff = MSDOSFSROOT_OFS;
398 else
399 blkoff = 0;
400 } else if (cluster == MSDOSFSROOT)
401 blkoff = diroff;
402
403 /*
404 * Now release buf to allow deget to read the entry again.
405 * Reserving it here and giving it to deget could result
406 * in a deadlock.
407 */
408 brelse(bp);
409 bp = 0;
410
411 foundroot:
412 /*
413 * If we entered at foundroot, then we are looking for the . or ..
414 * entry of the filesystems root directory. isadir and scn were
415 * setup before jumping here. And, bp is already null.
416 */
417 if (FAT32(pmp) && scn == MSDOSFSROOT)
418 scn = pmp->pm_rootdirblk;
419
420 /*
421 * If deleting, and at end of pathname, return
422 * parameters which can be used to remove file.
423 * If the wantparent flag isn't set, we return only
424 * the directory (in ndp->ni_dvp), otherwise we go
425 * on and lock the inode, being careful with ".".
426 */
427 if (nameiop == DELETE && (flags & ISLASTCN)) {
428 /*
429 * Don't allow deleting the root.
430 */
431 if (blkoff == MSDOSFSROOT_OFS)
432 return EROFS; /* really? XXX */
433
434 /*
435 * Write access to directory required to delete files.
436 */
437 error = VOP_ACCESS(vdp, VWRITE, cnp->cn_cred, cnp->cn_proc);
438 if (error)
439 return (error);
440
441 /*
442 * Return pointer to current entry in dp->i_offset.
443 * Save directory inode pointer in ndp->ni_dvp for dirremove().
444 */
445 if (dp->de_StartCluster == scn && isadir) { /* "." */
446 VREF(vdp);
447 *vpp = vdp;
448 return (0);
449 }
450 error = deget(pmp, cluster, blkoff, &tdp);
451 if (error)
452 return (error);
453 *vpp = DETOV(tdp);
454 if (!lockparent)
455 VOP_UNLOCK(vdp, 0, p);
456 return (0);
457 }
458
459 /*
460 * If rewriting (RENAME), return the inode and the
461 * information required to rewrite the present directory
462 * Must get inode of directory entry to verify it's a
463 * regular file, or empty directory.
464 */
465 if (nameiop == RENAME && wantparent &&
466 (flags & ISLASTCN)) {
467 if (blkoff == MSDOSFSROOT_OFS)
468 return EROFS; /* really? XXX */
469
470 error = VOP_ACCESS(vdp, VWRITE, cnp->cn_cred, cnp->cn_proc);
471 if (error)
472 return (error);
473
474 /*
475 * Careful about locking second inode.
476 * This can only occur if the target is ".".
477 */
478 if (dp->de_StartCluster == scn && isadir)
479 return (EISDIR);
480
481 if ((error = deget(pmp, cluster, blkoff, &tdp)) != 0)
482 return (error);
483 *vpp = DETOV(tdp);
484 cnp->cn_flags |= SAVENAME;
485 if (!lockparent)
486 VOP_UNLOCK(vdp, 0, p);
487 return (0);
488 }
489
490 /*
491 * Step through the translation in the name. We do not `vput' the
492 * directory because we may need it again if a symbolic link
493 * is relative to the current directory. Instead we save it
494 * unlocked as "pdp". We must get the target inode before unlocking
495 * the directory to insure that the inode will not be removed
496 * before we get it. We prevent deadlock by always fetching
497 * inodes from the root, moving down the directory tree. Thus
498 * when following backward pointers ".." we must unlock the
499 * parent directory before getting the requested directory.
500 * There is a potential race condition here if both the current
501 * and parent directories are removed before the VFS_VGET for the
502 * inode associated with ".." returns. We hope that this occurs
503 * infrequently since we cannot avoid this race condition without
504 * implementing a sophisticated deadlock detection algorithm.
505 * Note also that this simple deadlock detection scheme will not
506 * work if the file system has any hard links other than ".."
507 * that point backwards in the directory structure.
508 */
509 pdp = vdp;
510 if (flags & ISDOTDOT) {
511 VOP_UNLOCK(pdp, 0, p);
512 error = deget(pmp, cluster, blkoff, &tdp);
513 if (error) {
514 vn_lock(pdp, LK_EXCLUSIVE | LK_RETRY, p);
515 return (error);
516 }
517 if (lockparent && (flags & ISLASTCN) &&
518 (error = vn_lock(pdp, LK_EXCLUSIVE, p))) {
519 vput(DETOV(tdp));
520 return (error);
521 }
522 *vpp = DETOV(tdp);
523 } else if (dp->de_StartCluster == scn && isadir) {
524 VREF(vdp); /* we want ourself, ie "." */
525 *vpp = vdp;
526 } else {
527 if ((error = deget(pmp, cluster, blkoff, &tdp)) != 0)
528 return (error);
529 if (!lockparent || !(flags & ISLASTCN))
530 VOP_UNLOCK(pdp, 0, p);
531 *vpp = DETOV(tdp);
532 }
533
534 /*
535 * Insert name into cache if appropriate.
536 */
537 if (cnp->cn_flags & MAKEENTRY)
538 cache_enter(vdp, *vpp, cnp);
539 return (0);
540 }
541
542 /*
543 * dep - directory entry to copy into the directory
544 * ddep - directory to add to
545 * depp - return the address of the denode for the created directory entry
546 * if depp != 0
547 * cnp - componentname needed for Win95 long filenames
548 */
549 int
550 createde(dep, ddep, depp, cnp)
551 struct denode *dep;
552 struct denode *ddep;
553 struct denode **depp;
554 struct componentname *cnp;
555 {
556 int error;
557 u_long dirclust, diroffset;
558 struct direntry *ndep;
559 struct msdosfsmount *pmp = ddep->de_pmp;
560 struct buf *bp;
561 daddr_t bn;
562 int blsize;
563
564 #ifdef MSDOSFS_DEBUG
565 printf("createde(dep %p, ddep %p, depp %p, cnp %p)\n",
566 dep, ddep, depp, cnp);
567 #endif
568
569 /*
570 * If no space left in the directory then allocate another cluster
571 * and chain it onto the end of the file. There is one exception
572 * to this. That is, if the root directory has no more space it
573 * can NOT be expanded. extendfile() checks for and fails attempts
574 * to extend the root directory. We just return an error in that
575 * case.
576 */
577 if (ddep->de_fndoffset >= ddep->de_FileSize) {
578 diroffset = ddep->de_fndoffset + sizeof(struct direntry)
579 - ddep->de_FileSize;
580 dirclust = de_clcount(pmp, diroffset);
581 error = extendfile(ddep, dirclust, 0, 0, DE_CLEAR);
582 if (error) {
583 (void)detrunc(ddep, ddep->de_FileSize, 0, NOCRED, NULL);
584 return error;
585 }
586
587 /*
588 * Update the size of the directory
589 */
590 ddep->de_FileSize += de_cn2off(pmp, dirclust);
591 }
592
593 /*
594 * We just read in the cluster with space. Copy the new directory
595 * entry in. Then write it to disk. NOTE: DOS directories
596 * do not get smaller as clusters are emptied.
597 */
598 error = pcbmap(ddep, de_cluster(pmp, ddep->de_fndoffset),
599 &bn, &dirclust, &blsize);
600 if (error)
601 return error;
602 diroffset = ddep->de_fndoffset;
603 if (dirclust != MSDOSFSROOT)
604 diroffset &= pmp->pm_crbomask;
605 if ((error = bread(pmp->pm_devvp, bn, blsize, NOCRED, &bp)) != 0) {
606 brelse(bp);
607 return error;
608 }
609 ndep = bptoep(pmp, bp, ddep->de_fndoffset);
610
611 DE_EXTERNALIZE(ndep, dep);
612
613 /*
614 * Now write the Win95 long name
615 */
616 if (ddep->de_fndcnt > 0) {
617 u_int8_t chksum = winChksum(ndep->deName);
618 const u_char *un = (const u_char *)cnp->cn_nameptr;
619 int unlen = cnp->cn_namelen;
620 int cnt = 1;
621
622 while (--ddep->de_fndcnt >= 0) {
623 if (!(ddep->de_fndoffset & pmp->pm_crbomask)) {
624 if ((error = bwrite(bp)) != 0)
625 return error;
626
627 ddep->de_fndoffset -= sizeof(struct direntry);
628 error = pcbmap(ddep,
629 de_cluster(pmp,
630 ddep->de_fndoffset),
631 &bn, 0, &blsize);
632 if (error)
633 return error;
634
635 error = bread(pmp->pm_devvp, bn, blsize,
636 NOCRED, &bp);
637 if (error) {
638 brelse(bp);
639 return error;
640 }
641 ndep = bptoep(pmp, bp, ddep->de_fndoffset);
642 } else {
643 ndep--;
644 ddep->de_fndoffset -= sizeof(struct direntry);
645 }
646 if (!unix2winfn(un, unlen, (struct winentry *)ndep,
647 cnt++, chksum,
648 pmp->pm_flags & MSDOSFSMNT_U2WTABLE,
649 pmp->pm_u2w))
650 break;
651 }
652 }
653
654 if ((error = bwrite(bp)) != 0)
655 return error;
656
657 /*
658 * If they want us to return with the denode gotten.
659 */
660 if (depp) {
661 if (dep->de_Attributes & ATTR_DIRECTORY) {
662 dirclust = dep->de_StartCluster;
663 if (FAT32(pmp) && dirclust == pmp->pm_rootdirblk)
664 dirclust = MSDOSFSROOT;
665 if (dirclust == MSDOSFSROOT)
666 diroffset = MSDOSFSROOT_OFS;
667 else
668 diroffset = 0;
669 }
670 return deget(pmp, dirclust, diroffset, depp);
671 }
672
673 return 0;
674 }
675
676 /*
677 * Be sure a directory is empty except for "." and "..". Return 1 if empty,
678 * return 0 if not empty or error.
679 */
680 int
681 dosdirempty(dep)
682 struct denode *dep;
683 {
684 int blsize;
685 int error;
686 u_long cn;
687 daddr_t bn;
688 struct buf *bp;
689 struct msdosfsmount *pmp = dep->de_pmp;
690 struct direntry *dentp;
691
692 /*
693 * Since the filesize field in directory entries for a directory is
694 * zero, we just have to feel our way through the directory until
695 * we hit end of file.
696 */
697 for (cn = 0;; cn++) {
698 if ((error = pcbmap(dep, cn, &bn, 0, &blsize)) != 0) {
699 if (error == E2BIG)
700 return (1); /* it's empty */
701 return (0);
702 }
703 error = bread(pmp->pm_devvp, bn, blsize, NOCRED, &bp);
704 if (error) {
705 brelse(bp);
706 return (0);
707 }
708 for (dentp = (struct direntry *)bp->b_data;
709 (char *)dentp < bp->b_data + blsize;
710 dentp++) {
711 if (dentp->deName[0] != SLOT_DELETED &&
712 (dentp->deAttributes & ATTR_VOLUME) == 0) {
713 /*
714 * In dos directories an entry whose name
715 * starts with SLOT_EMPTY (0) starts the
716 * beginning of the unused part of the
717 * directory, so we can just return that it
718 * is empty.
719 */
720 if (dentp->deName[0] == SLOT_EMPTY) {
721 brelse(bp);
722 return (1);
723 }
724 /*
725 * Any names other than "." and ".." in a
726 * directory mean it is not empty.
727 */
728 if (bcmp(dentp->deName, ". ", 11) &&
729 bcmp(dentp->deName, ".. ", 11)) {
730 brelse(bp);
731 #ifdef MSDOSFS_DEBUG
732 printf("dosdirempty(): entry found %02x, %02x\n",
733 dentp->deName[0], dentp->deName[1]);
734 #endif
735 return (0); /* not empty */
736 }
737 }
738 }
739 brelse(bp);
740 }
741 /* NOTREACHED */
742 }
743
744 /*
745 * Check to see if the directory described by target is in some
746 * subdirectory of source. This prevents something like the following from
747 * succeeding and leaving a bunch or files and directories orphaned. mv
748 * /a/b/c /a/b/c/d/e/f Where c and f are directories.
749 *
750 * source - the inode for /a/b/c
751 * target - the inode for /a/b/c/d/e/f
752 *
753 * Returns 0 if target is NOT a subdirectory of source.
754 * Otherwise returns a non-zero error number.
755 * The target inode is always unlocked on return.
756 */
757 int
758 doscheckpath(source, target)
759 struct denode *source;
760 struct denode *target;
761 {
762 daddr_t scn;
763 struct msdosfsmount *pmp;
764 struct direntry *ep;
765 struct denode *dep;
766 struct buf *bp = NULL;
767 int error = 0;
768
769 dep = target;
770 if ((target->de_Attributes & ATTR_DIRECTORY) == 0 ||
771 (source->de_Attributes & ATTR_DIRECTORY) == 0) {
772 error = ENOTDIR;
773 goto out;
774 }
775 if (dep->de_StartCluster == source->de_StartCluster) {
776 error = EEXIST;
777 goto out;
778 }
779 if (dep->de_StartCluster == MSDOSFSROOT)
780 goto out;
781 pmp = dep->de_pmp;
782 #ifdef DIAGNOSTIC
783 if (pmp != source->de_pmp)
784 panic("doscheckpath: source and target on different filesystems");
785 #endif
786 if (FAT32(pmp) && dep->de_StartCluster == pmp->pm_rootdirblk)
787 goto out;
788
789 for (;;) {
790 if ((dep->de_Attributes & ATTR_DIRECTORY) == 0) {
791 error = ENOTDIR;
792 break;
793 }
794 scn = dep->de_StartCluster;
795 error = bread(pmp->pm_devvp, cntobn(pmp, scn),
796 pmp->pm_bpcluster, NOCRED, &bp);
797 if (error)
798 break;
799
800 ep = (struct direntry *) bp->b_data + 1;
801 if ((ep->deAttributes & ATTR_DIRECTORY) == 0 ||
802 bcmp(ep->deName, ".. ", 11) != 0) {
803 error = ENOTDIR;
804 break;
805 }
806 scn = getushort(ep->deStartCluster);
807 if (FAT32(pmp))
808 scn |= getushort(ep->deHighClust) << 16;
809
810 if (scn == source->de_StartCluster) {
811 error = EINVAL;
812 break;
813 }
814 if (scn == MSDOSFSROOT)
815 break;
816 if (FAT32(pmp) && scn == pmp->pm_rootdirblk) {
817 /*
818 * scn should be 0 in this case,
819 * but we silently ignore the error.
820 */
821 break;
822 }
823
824 vput(DETOV(dep));
825 brelse(bp);
826 bp = NULL;
827 /* NOTE: deget() clears dep on error */
828 if ((error = deget(pmp, scn, 0, &dep)) != 0)
829 break;
830 }
831 out:;
832 if (bp)
833 brelse(bp);
834 if (error == ENOTDIR)
835 printf("doscheckpath(): .. not a directory?\n");
836 if (dep != NULL)
837 vput(DETOV(dep));
838 return (error);
839 }
840
841 /*
842 * Read in the disk block containing the directory entry (dirclu, dirofs)
843 * and return the address of the buf header, and the address of the
844 * directory entry within the block.
845 */
846 int
847 readep(pmp, dirclust, diroffset, bpp, epp)
848 struct msdosfsmount *pmp;
849 u_long dirclust, diroffset;
850 struct buf **bpp;
851 struct direntry **epp;
852 {
853 int error;
854 daddr_t bn;
855 int blsize;
856
857 blsize = pmp->pm_bpcluster;
858 if (dirclust == MSDOSFSROOT
859 && de_blk(pmp, diroffset + blsize) > pmp->pm_rootdirsize)
860 blsize = de_bn2off(pmp, pmp->pm_rootdirsize) & pmp->pm_crbomask;
861 bn = detobn(pmp, dirclust, diroffset);
862 if ((error = bread(pmp->pm_devvp, bn, blsize, NOCRED, bpp)) != 0) {
863 brelse(*bpp);
864 *bpp = NULL;
865 return (error);
866 }
867 if (epp)
868 *epp = bptoep(pmp, *bpp, diroffset);
869 return (0);
870 }
871
872 /*
873 * Read in the disk block containing the directory entry dep came from and
874 * return the address of the buf header, and the address of the directory
875 * entry within the block.
876 */
877 int
878 readde(dep, bpp, epp)
879 struct denode *dep;
880 struct buf **bpp;
881 struct direntry **epp;
882 {
883
884 return (readep(dep->de_pmp, dep->de_dirclust, dep->de_diroffset,
885 bpp, epp));
886 }
887
888 /*
889 * Remove a directory entry. At this point the file represented by the
890 * directory entry to be removed is still full length until noone has it
891 * open. When the file no longer being used msdosfs_inactive() is called
892 * and will truncate the file to 0 length. When the vnode containing the
893 * denode is needed for some other purpose by VFS it will call
894 * msdosfs_reclaim() which will remove the denode from the denode cache.
895 */
896 int
897 removede(pdep, dep)
898 struct denode *pdep; /* directory where the entry is removed */
899 struct denode *dep; /* file to be removed */
900 {
901 int error;
902 struct direntry *ep;
903 struct buf *bp;
904 daddr_t bn;
905 int blsize;
906 struct msdosfsmount *pmp = pdep->de_pmp;
907 u_long offset = pdep->de_fndoffset;
908
909 #ifdef MSDOSFS_DEBUG
910 printf("removede(): filename %s, dep %p, offset %08lx\n",
911 dep->de_Name, dep, offset);
912 #endif
913
914 dep->de_refcnt--;
915 offset += sizeof(struct direntry);
916 do {
917 offset -= sizeof(struct direntry);
918 error = pcbmap(pdep, de_cluster(pmp, offset), &bn, 0, &blsize);
919 if (error)
920 return error;
921 error = bread(pmp->pm_devvp, bn, blsize, NOCRED, &bp);
922 if (error) {
923 brelse(bp);
924 return error;
925 }
926 ep = bptoep(pmp, bp, offset);
927 /*
928 * Check whether, if we came here the second time, i.e.
929 * when underflowing into the previous block, the last
930 * entry in this block is a longfilename entry, too.
931 */
932 if (ep->deAttributes != ATTR_WIN95
933 && offset != pdep->de_fndoffset) {
934 brelse(bp);
935 break;
936 }
937 offset += sizeof(struct direntry);
938 while (1) {
939 /*
940 * We are a bit agressive here in that we delete any Win95
941 * entries preceding this entry, not just the ones we "own".
942 * Since these presumably aren't valid anyway,
943 * there should be no harm.
944 */
945 offset -= sizeof(struct direntry);
946 ep--->deName[0] = SLOT_DELETED;
947 if ((pmp->pm_flags & MSDOSFSMNT_NOWIN95)
948 || !(offset & pmp->pm_crbomask)
949 || ep->deAttributes != ATTR_WIN95)
950 break;
951 }
952 if ((error = bwrite(bp)) != 0)
953 return error;
954 } while (!(pmp->pm_flags & MSDOSFSMNT_NOWIN95)
955 && !(offset & pmp->pm_crbomask)
956 && offset);
957 return 0;
958 }
959
960 /*
961 * Create a unique DOS name in dvp
962 */
963 int
964 uniqdosname(dep, cnp, cp)
965 struct denode *dep;
966 struct componentname *cnp;
967 u_char *cp;
968 {
969 struct msdosfsmount *pmp = dep->de_pmp;
970 struct direntry *dentp;
971 int gen;
972 int blsize;
973 u_long cn;
974 daddr_t bn;
975 struct buf *bp;
976 int error;
977
978 if (pmp->pm_flags & MSDOSFSMNT_SHORTNAME)
979 return (unix2dosfn((const u_char *)cnp->cn_nameptr, cp,
980 cnp->cn_namelen, 0,
981 pmp->pm_flags & MSDOSFSMNT_U2WTABLE, pmp->pm_u2d,
982 pmp->pm_flags & MSDOSFSMNT_ULTABLE, pmp->pm_lu) ?
983 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,
991 pmp->pm_flags & MSDOSFSMNT_U2WTABLE, pmp->pm_u2d,
992 pmp->pm_flags & MSDOSFSMNT_ULTABLE, pmp->pm_lu))
993 return gen == 1 ? EINVAL : EEXIST;
994
995 /*
996 * Now look for a dir entry with this exact name
997 */
998 for (cn = error = 0; !error; cn++) {
999 if ((error = pcbmap(dep, cn, &bn, 0, &blsize)) != 0) {
1000 if (error == E2BIG) /* EOF reached and not found */
1001 return 0;
1002 return error;
1003 }
1004 error = bread(pmp->pm_devvp, bn, blsize, NOCRED, &bp);
1005 if (error) {
1006 brelse(bp);
1007 return error;
1008 }
1009 for (dentp = (struct direntry *)bp->b_data;
1010 (char *)dentp < bp->b_data + blsize;
1011 dentp++) {
1012 if (dentp->deName[0] == SLOT_EMPTY) {
1013 /*
1014 * Last used entry and not found
1015 */
1016 brelse(bp);
1017 return 0;
1018 }
1019 /*
1020 * Ignore volume labels and Win95 entries
1021 */
1022 if (dentp->deAttributes & ATTR_VOLUME)
1023 continue;
1024 if (!bcmp(dentp->deName, cp, 11)) {
1025 error = EEXIST;
1026 break;
1027 }
1028 }
1029 brelse(bp);
1030 }
1031 }
1032 }
1033
1034 /*
1035 * Find any Win'95 long filename entry in directory dep
1036 */
1037 int
1038 findwin95(dep)
1039 struct denode *dep;
1040 {
1041 struct msdosfsmount *pmp = dep->de_pmp;
1042 struct direntry *dentp;
1043 int blsize, win95;
1044 u_long cn;
1045 daddr_t bn;
1046 struct buf *bp;
1047
1048 win95 = 1;
1049 /*
1050 * Read through the directory looking for Win'95 entries
1051 * Note: Error currently handled just as EOF XXX
1052 */
1053 for (cn = 0;; cn++) {
1054 if (pcbmap(dep, cn, &bn, 0, &blsize))
1055 return (win95);
1056 if (bread(pmp->pm_devvp, bn, blsize, NOCRED, &bp)) {
1057 brelse(bp);
1058 return (win95);
1059 }
1060 for (dentp = (struct direntry *)bp->b_data;
1061 (char *)dentp < bp->b_data + blsize;
1062 dentp++) {
1063 if (dentp->deName[0] == SLOT_EMPTY) {
1064 /*
1065 * Last used entry and not found
1066 */
1067 brelse(bp);
1068 return (win95);
1069 }
1070 if (dentp->deName[0] == SLOT_DELETED) {
1071 /*
1072 * Ignore deleted files
1073 * Note: might be an indication of Win'95 anyway XXX
1074 */
1075 continue;
1076 }
1077 if (dentp->deAttributes == ATTR_WIN95) {
1078 brelse(bp);
1079 return 1;
1080 }
1081 win95 = 0;
1082 }
1083 brelse(bp);
1084 }
1085 }
Cache object: 8b1d491bc05c3703ce8c1d3827a64550
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