1 /* $OpenBSD: msdosfs_lookup.c,v 1.19 2007/06/02 02:04:21 deraadt Exp $ */
2 /* $NetBSD: msdosfs_lookup.c,v 1.34 1997/10/18 22:12:27 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/buf.h>
55 #include <sys/vnode.h>
56 #include <sys/mount.h>
57 #include <sys/dirent.h>
58
59 #include <msdosfs/bpb.h>
60 #include <msdosfs/direntry.h>
61 #include <msdosfs/denode.h>
62 #include <msdosfs/msdosfsmount.h>
63 #include <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(v)
82 void *v;
83 {
84 struct vop_lookup_args *ap = v;
85 struct vnode *vdp = ap->a_dvp;
86 struct vnode **vpp = ap->a_vpp;
87 struct componentname *cnp = ap->a_cnp;
88 struct proc *p = cnp->cn_proc;
89 daddr64_t bn;
90 int error;
91 int lockparent;
92 int wantparent;
93 int slotcount;
94 int slotoffset = 0;
95 int frcn;
96 uint32_t cluster;
97 int blkoff;
98 int diroff;
99 int blsize;
100 int isadir; /* ~0 if found direntry is a directory */
101 uint32_t 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;
108 u_char dosfilename[12];
109 u_char *adjp;
110 int adjlen;
111 int flags;
112 int nameiop = cnp->cn_nameiop;
113 int wincnt = 1;
114 int chksum = -1, chksum_ok;
115 int olddos = 1;
116
117 cnp->cn_flags &= ~PDIRUNLOCK; /* XXX why this ?? */
118 flags = cnp->cn_flags;
119
120 #ifdef MSDOSFS_DEBUG
121 printf("msdosfs_lookup(): looking for %s\n", cnp->cn_nameptr);
122 #endif
123 dp = VTODE(vdp);
124 pmp = dp->de_pmp;
125 *vpp = NULL;
126 lockparent = flags & LOCKPARENT;
127 wantparent = flags & (LOCKPARENT | WANTPARENT);
128 #ifdef MSDOSFS_DEBUG
129 printf("msdosfs_lookup(): vdp %08x, dp %08x, Attr %02x\n",
130 vdp, dp, dp->de_Attributes);
131 #endif
132
133 /*
134 * Check accessiblity of directory.
135 */
136 if ((dp->de_Attributes & ATTR_DIRECTORY) == 0)
137 return (ENOTDIR);
138 if ((error = VOP_ACCESS(vdp, VEXEC, cnp->cn_cred, cnp->cn_proc)) != 0)
139 return (error);
140
141 /*
142 * We now have a segment name to search for, and a directory to search.
143 *
144 * Before tediously performing a linear scan of the directory,
145 * check the name cache to see if the directory/name pair
146 * we are looking for is known already.
147 */
148 if ((error = cache_lookup(vdp, vpp, cnp)) >= 0)
149 return (error);
150
151 /*
152 * If they are going after the . or .. entry in the root directory,
153 * they won't find it. DOS filesystems don't have them in the root
154 * directory. So, we fake it. deget() is in on this scam too.
155 */
156 if ((vdp->v_flag & VROOT) && cnp->cn_nameptr[0] == '.' &&
157 (cnp->cn_namelen == 1 ||
158 (cnp->cn_namelen == 2 && cnp->cn_nameptr[1] == '.'))) {
159 isadir = ATTR_DIRECTORY;
160 scn = MSDOSFSROOT;
161 #ifdef MSDOSFS_DEBUG
162 printf("msdosfs_lookup(): looking for . or .. in root directory\n");
163 #endif
164 cluster = MSDOSFSROOT;
165 blkoff = MSDOSFSROOT_OFS;
166 goto foundroot;
167 }
168
169 switch (unix2dosfn((u_char *)cnp->cn_nameptr, dosfilename, cnp->cn_namelen, 0)) {
170 case 0:
171 return (EINVAL);
172 case 1:
173 break;
174 case 2:
175 wincnt = winSlotCnt((u_char *)cnp->cn_nameptr, cnp->cn_namelen) + 1;
176 break;
177 case 3:
178 olddos = 0;
179 wincnt = winSlotCnt((u_char *)cnp->cn_nameptr, cnp->cn_namelen) + 1;
180 break;
181 }
182 if (pmp->pm_flags & MSDOSFSMNT_SHORTNAME)
183 wincnt = 1;
184
185 /*
186 * Suppress search for slots unless creating
187 * file and at end of pathname, in which case
188 * we watch for a place to put the new file in
189 * case it doesn't already exist.
190 */
191 slotcount = wincnt;
192 if ((nameiop == CREATE || nameiop == RENAME) &&
193 (flags & ISLASTCN))
194 slotcount = 0;
195
196 #ifdef MSDOSFS_DEBUG
197 printf("msdosfs_lookup(): dos version of filename %s, length %d\n",
198 dosfilename, cnp->cn_namelen);
199 #endif
200 /*
201 * We want to search the directory pointed to by vdp for the name
202 * pointed to by cnp->cn_nameptr.
203 *
204 * XXX UNIX allows filenames with trailing dots and blanks; we don't.
205 * Most of the routines in msdosfs_conv.c adjust for this, but
206 * winChkName() does not, so we do it here. Otherwise, a file
207 * such as ".foobar." cannot be retrieved properly.
208 *
209 * (Note that this is also faster: perform the adjustment once,
210 * rather than on each call to winChkName. However, it is still
211 * a nasty hack.)
212 */
213 adjp = cnp->cn_nameptr;
214 adjlen = cnp->cn_namelen;
215
216 for (adjp += adjlen; adjlen > 0; adjlen--)
217 if (*--adjp != ' ' && *adjp != '.')
218 break;
219
220 tdp = NULL;
221 /*
222 * The outer loop ranges over the clusters that make up the
223 * directory. Note that the root directory is different from all
224 * other directories. It has a fixed number of blocks that are not
225 * part of the pool of allocatable clusters. So, we treat it a
226 * little differently. The root directory starts at "cluster" 0.
227 */
228 diroff = 0;
229 for (frcn = 0;; frcn++) {
230 if ((error = pcbmap(dp, frcn, &bn, &cluster, &blsize)) != 0) {
231 if (error == E2BIG)
232 break;
233 return (error);
234 }
235 error = bread(pmp->pm_devvp, bn, blsize, NOCRED, &bp);
236 if (error) {
237 brelse(bp);
238 return (error);
239 }
240 for (blkoff = 0; blkoff < blsize;
241 blkoff += sizeof(struct direntry),
242 diroff += sizeof(struct direntry)) {
243 dep = (struct direntry *)(bp->b_data + blkoff);
244 /*
245 * If the slot is empty and we are still looking
246 * for an empty then remember this one. If the
247 * slot is not empty then check to see if it
248 * matches what we are looking for. If the slot
249 * has never been filled with anything, then the
250 * remainder of the directory has never been used,
251 * so there is no point in searching it.
252 */
253 if (dep->deName[0] == SLOT_EMPTY ||
254 dep->deName[0] == SLOT_DELETED) {
255 /*
256 * Drop memory of previous long matches
257 */
258 chksum = -1;
259
260 if (slotcount < wincnt) {
261 slotcount++;
262 slotoffset = diroff;
263 }
264 if (dep->deName[0] == SLOT_EMPTY) {
265 brelse(bp);
266 goto notfound;
267 }
268 } else {
269 /*
270 * If there wasn't enough space for our winentries,
271 * forget about the empty space
272 */
273 if (slotcount < wincnt)
274 slotcount = 0;
275
276 /*
277 * Check for Win95 long filename entry
278 */
279 if (dep->deAttributes == ATTR_WIN95) {
280 if (pmp->pm_flags & MSDOSFSMNT_SHORTNAME)
281 continue;
282
283 chksum = winChkName((u_char *)cnp->cn_nameptr,
284 adjlen,
285 (struct winentry *)dep,
286 chksum);
287 continue;
288 }
289
290 /*
291 * Ignore volume labels (anywhere, not just
292 * the root directory).
293 */
294 if (dep->deAttributes & ATTR_VOLUME) {
295 chksum = -1;
296 continue;
297 }
298
299 /*
300 * Check for a checksum or name match
301 */
302 chksum_ok = (chksum == winChksum(dep->deName));
303 if (!chksum_ok
304 && (!olddos || bcmp(dosfilename, dep->deName, 11))) {
305 chksum = -1;
306 continue;
307 }
308 #ifdef MSDOSFS_DEBUG
309 printf("msdosfs_lookup(): match blkoff %d, diroff %d\n",
310 blkoff, diroff);
311 #endif
312 /*
313 * Remember where this directory
314 * entry came from for whoever did
315 * this lookup.
316 */
317 dp->de_fndoffset = diroff;
318 if (chksum_ok && nameiop == RENAME) {
319 /*
320 * Target had correct long name
321 * directory entries, reuse them as
322 * needed.
323 */
324 dp->de_fndcnt = wincnt - 1;
325 } else {
326 /*
327 * Long name directory entries not
328 * present or corrupt, can only reuse
329 * dos directory entry.
330 */
331 dp->de_fndcnt = 0;
332 }
333 goto found;
334 }
335 } /* for (blkoff = 0; .... */
336 /*
337 * Release the buffer holding the directory cluster just
338 * searched.
339 */
340 brelse(bp);
341 } /* for (frcn = 0; ; frcn++) */
342
343 notfound:;
344 /*
345 * We hold no disk buffers at this point.
346 */
347
348 /*
349 * Fixup the slot description to point to the place where
350 * we might put the new DOS direntry (putting the Win95
351 * long name entries before that)
352 */
353 if (!slotcount) {
354 slotcount = 1;
355 slotoffset = diroff;
356 }
357 if (wincnt > slotcount)
358 slotoffset += sizeof(struct direntry) * (wincnt - slotcount);
359
360 /*
361 * If we get here we didn't find the entry we were looking for. But
362 * that's ok if we are creating or renaming and are at the end of
363 * the pathname and the directory hasn't been removed.
364 */
365 #ifdef MSDOSFS_DEBUG
366 printf("msdosfs_lookup(): op %d, refcnt %d\n",
367 nameiop, dp->de_refcnt);
368 printf(" slotcount %d, slotoffset %d\n",
369 slotcount, slotoffset);
370 #endif
371 if ((nameiop == CREATE || nameiop == RENAME) &&
372 (flags & ISLASTCN) && dp->de_refcnt != 0) {
373 /*
374 * Access for write is interpreted as allowing
375 * creation of files in the directory.
376 */
377 error = VOP_ACCESS(vdp, VWRITE, cnp->cn_cred, cnp->cn_proc);
378 if (error)
379 return (error);
380 /*
381 * Return an indication of where the new directory
382 * entry should be put.
383 */
384 dp->de_fndoffset = slotoffset;
385 dp->de_fndcnt = wincnt - 1;
386
387 /*
388 * We return with the directory locked, so that
389 * the parameters we set up above will still be
390 * valid if we actually decide to do a direnter().
391 * We return ni_vp == NULL to indicate that the entry
392 * does not currently exist; we leave a pointer to
393 * the (locked) directory inode in ndp->ni_dvp.
394 * The pathname buffer is saved so that the name
395 * can be obtained later.
396 *
397 * NB - if the directory is unlocked, then this
398 * information cannot be used.
399 */
400 cnp->cn_flags |= SAVENAME;
401 if (!lockparent) {
402 VOP_UNLOCK(vdp, 0, p);
403 cnp->cn_flags |= PDIRUNLOCK;
404 }
405 return (EJUSTRETURN);
406 }
407 /*
408 * Insert name into cache (as non-existent) if appropriate.
409 */
410 if ((cnp->cn_flags & MAKEENTRY) && nameiop != CREATE)
411 cache_enter(vdp, *vpp, cnp);
412 return (ENOENT);
413
414 found:;
415 /*
416 * NOTE: We still have the buffer with matched directory entry at
417 * this point.
418 */
419 isadir = dep->deAttributes & ATTR_DIRECTORY;
420 scn = getushort(dep->deStartCluster);
421 if (FAT32(pmp)) {
422 scn |= getushort(dep->deHighClust) << 16;
423 if (scn == pmp->pm_rootdirblk) {
424 /*
425 * There should actually be 0 here.
426 * Just ignore the error.
427 */
428 scn = MSDOSFSROOT;
429 }
430 }
431
432 if (cluster == MSDOSFSROOT)
433 blkoff = diroff;
434
435 if (isadir) {
436 cluster = scn;
437 if (cluster == MSDOSFSROOT)
438 blkoff = MSDOSFSROOT_OFS;
439 else
440 blkoff = 0;
441 }
442
443 /*
444 * Now release buf to allow deget to read the entry again.
445 * Reserving it here and giving it to deget could result
446 * in a deadlock.
447 */
448 brelse(bp);
449
450 foundroot:;
451 /*
452 * If we entered at foundroot, then we are looking for the . or ..
453 * entry of the filesystems root directory. isadir and scn were
454 * setup before jumping here. And, bp is already null.
455 */
456 if (FAT32(pmp) && scn == MSDOSFSROOT)
457 scn = pmp->pm_rootdirblk;
458
459 /*
460 * If deleting, and at end of pathname, return
461 * parameters which can be used to remove file.
462 * If the wantparent flag isn't set, we return only
463 * the directory (in ndp->ni_dvp), otherwise we go
464 * on and lock the inode, being careful with ".".
465 */
466 if (nameiop == DELETE && (flags & ISLASTCN)) {
467 /*
468 * Don't allow deleting the root.
469 */
470 if (blkoff == MSDOSFSROOT_OFS)
471 return EROFS; /* really? XXX */
472
473 /*
474 * Write access to directory required to delete files.
475 */
476 error = VOP_ACCESS(vdp, VWRITE, cnp->cn_cred, cnp->cn_proc);
477 if (error)
478 return (error);
479
480 /*
481 * Return pointer to current entry in dp->i_offset.
482 * Save directory inode pointer in ndp->ni_dvp for dirremove().
483 */
484 if (dp->de_StartCluster == scn && isadir) { /* "." */
485 VREF(vdp);
486 *vpp = vdp;
487 return (0);
488 }
489 if ((error = deget(pmp, cluster, blkoff, &tdp)) != 0)
490 return (error);
491 *vpp = DETOV(tdp);
492 if (!lockparent) {
493 VOP_UNLOCK(vdp, 0, p);
494 cnp->cn_flags |= PDIRUNLOCK;
495 }
496 return (0);
497 }
498
499 /*
500 * If rewriting (RENAME), return the inode and the
501 * information required to rewrite the present directory
502 * Must get inode of directory entry to verify it's a
503 * regular file, or empty directory.
504 */
505 if (nameiop == RENAME && wantparent &&
506 (flags & ISLASTCN)) {
507 if (blkoff == MSDOSFSROOT_OFS)
508 return EROFS; /* really? XXX */
509
510 error = VOP_ACCESS(vdp, VWRITE, cnp->cn_cred, cnp->cn_proc);
511 if (error)
512 return (error);
513
514 /*
515 * Careful about locking second inode.
516 * This can only occur if the target is ".".
517 */
518 if (dp->de_StartCluster == scn && isadir)
519 return (EISDIR);
520
521 if ((error = deget(pmp, cluster, blkoff, &tdp)) != 0)
522 return (error);
523 *vpp = DETOV(tdp);
524 cnp->cn_flags |= SAVENAME;
525 if (!lockparent)
526 VOP_UNLOCK(vdp, 0, p);
527 return (0);
528 }
529
530 /*
531 * Step through the translation in the name. We do not `vput' the
532 * directory because we may need it again if a symbolic link
533 * is relative to the current directory. Instead we save it
534 * unlocked as "pdp". We must get the target inode before unlocking
535 * the directory to insure that the inode will not be removed
536 * before we get it. We prevent deadlock by always fetching
537 * inodes from the root, moving down the directory tree. Thus
538 * when following backward pointers ".." we must unlock the
539 * parent directory before getting the requested directory.
540 * There is a potential race condition here if both the current
541 * and parent directories are removed before the VFS_VGET for the
542 * inode associated with ".." returns. We hope that this occurs
543 * infrequently since we cannot avoid this race condition without
544 * implementing a sophisticated deadlock detection algorithm.
545 * Note also that this simple deadlock detection scheme will not
546 * work if the file system has any hard links other than ".."
547 * that point backwards in the directory structure.
548 */
549 pdp = vdp;
550 if (flags & ISDOTDOT) {
551 VOP_UNLOCK(pdp, 0, p); /* race to get the inode */
552 cnp->cn_flags |= PDIRUNLOCK;
553 if ((error = deget(pmp, cluster, blkoff, &tdp)) != 0) {
554 if (vn_lock(pdp, LK_EXCLUSIVE | LK_RETRY, p) == 0)
555 cnp->cn_flags &= ~PDIRUNLOCK;
556 return (error);
557 }
558 if (lockparent && (flags & ISLASTCN)) {
559 if ((error = vn_lock(pdp, LK_EXCLUSIVE | LK_RETRY,
560 p))) {
561 vput(DETOV(tdp));
562 return (error);
563 }
564 cnp->cn_flags &= ~PDIRUNLOCK;
565 }
566 *vpp = DETOV(tdp);
567 } else if (dp->de_StartCluster == scn && isadir) {
568 VREF(vdp); /* we want ourself, ie "." */
569 *vpp = vdp;
570 } else {
571 if ((error = deget(pmp, cluster, blkoff, &tdp)) != 0)
572 return (error);
573 if (!lockparent || !(flags & ISLASTCN)) {
574 VOP_UNLOCK(pdp, 0, p);
575 cnp->cn_flags |= PDIRUNLOCK;
576 }
577 *vpp = DETOV(tdp);
578 }
579
580 /*
581 * Insert name into cache if appropriate.
582 */
583 if (cnp->cn_flags & MAKEENTRY)
584 cache_enter(vdp, *vpp, cnp);
585 return (0);
586 }
587
588 /*
589 * dep - directory entry to copy into the directory
590 * ddep - directory to add to
591 * depp - return the address of the denode for the created directory entry
592 * if depp != 0
593 * cnp - componentname needed for Win95 long filenames
594 */
595 int
596 createde(dep, ddep, depp, cnp)
597 struct denode *dep;
598 struct denode *ddep;
599 struct denode **depp;
600 struct componentname *cnp;
601 {
602 int error;
603 uint32_t dirclust, diroffset;
604 struct direntry *ndep;
605 struct msdosfsmount *pmp = ddep->de_pmp;
606 struct buf *bp;
607 daddr64_t bn;
608 int blsize;
609
610 #ifdef MSDOSFS_DEBUG
611 printf("createde(dep %08x, ddep %08x, depp %08x, cnp %08x)\n",
612 dep, ddep, depp, cnp);
613 #endif
614
615 /*
616 * If no space left in the directory then allocate another cluster
617 * and chain it onto the end of the file. There is one exception
618 * to this. That is, if the root directory has no more space it
619 * can NOT be expanded. extendfile() checks for and fails attempts
620 * to extend the root directory. We just return an error in that
621 * case.
622 */
623 if (ddep->de_fndoffset >= ddep->de_FileSize) {
624 diroffset = ddep->de_fndoffset + sizeof(struct direntry)
625 - ddep->de_FileSize;
626 dirclust = de_clcount(pmp, diroffset);
627 if ((error = extendfile(ddep, dirclust, 0, 0, DE_CLEAR)) != 0) {
628 (void)detrunc(ddep, ddep->de_FileSize, 0, NOCRED, NULL);
629 return error;
630 }
631
632 /*
633 * Update the size of the directory
634 */
635 ddep->de_FileSize += de_cn2off(pmp, dirclust);
636 }
637
638 /*
639 * We just read in the cluster with space. Copy the new directory
640 * entry in. Then write it to disk. NOTE: DOS directories
641 * do not get smaller as clusters are emptied.
642 */
643 error = pcbmap(ddep, de_cluster(pmp, ddep->de_fndoffset),
644 &bn, &dirclust, &blsize);
645 if (error)
646 return error;
647 diroffset = ddep->de_fndoffset;
648 if (dirclust != MSDOSFSROOT)
649 diroffset &= pmp->pm_crbomask;
650 if ((error = bread(pmp->pm_devvp, bn, blsize, NOCRED, &bp)) != 0) {
651 brelse(bp);
652 return error;
653 }
654 ndep = bptoep(pmp, bp, ddep->de_fndoffset);
655
656 DE_EXTERNALIZE(ndep, dep);
657
658 /*
659 * Now write the Win95 long name
660 */
661 if (ddep->de_fndcnt > 0) {
662 u_int8_t chksum = winChksum(ndep->deName);
663 u_char *un = (u_char *)cnp->cn_nameptr;
664 int unlen = cnp->cn_namelen;
665 int cnt = 1;
666
667 while (--ddep->de_fndcnt >= 0) {
668 if (!(ddep->de_fndoffset & pmp->pm_crbomask)) {
669 if ((error = bwrite(bp)) != 0)
670 return error;
671
672 ddep->de_fndoffset -= sizeof(struct direntry);
673 error = pcbmap(ddep,
674 de_cluster(pmp,
675 ddep->de_fndoffset),
676 &bn, 0, &blsize);
677 if (error)
678 return error;
679
680 error = bread(pmp->pm_devvp, bn, blsize,
681 NOCRED, &bp);
682 if (error) {
683 brelse(bp);
684 return error;
685 }
686 ndep = bptoep(pmp, bp, ddep->de_fndoffset);
687 } else {
688 ndep--;
689 ddep->de_fndoffset -= sizeof(struct direntry);
690 }
691 if (!unix2winfn(un, unlen, (struct winentry *)ndep, cnt++, chksum))
692 break;
693 }
694 }
695
696 if ((error = bwrite(bp)) != 0)
697 return error;
698
699 /*
700 * If they want us to return with the denode gotten.
701 */
702 if (depp) {
703 if (dep->de_Attributes & ATTR_DIRECTORY) {
704 dirclust = dep->de_StartCluster;
705 if (FAT32(pmp) && dirclust == pmp->pm_rootdirblk)
706 dirclust = MSDOSFSROOT;
707 if (dirclust == MSDOSFSROOT)
708 diroffset = MSDOSFSROOT_OFS;
709 else
710 diroffset = 0;
711 }
712 return deget(pmp, dirclust, diroffset, depp);
713 }
714
715 return 0;
716 }
717
718 /*
719 * Be sure a directory is empty except for "." and "..". Return 1 if empty,
720 * return 0 if not empty or error.
721 */
722 int
723 dosdirempty(dep)
724 struct denode *dep;
725 {
726 int blsize;
727 int error;
728 uint32_t cn;
729 daddr64_t bn;
730 struct buf *bp;
731 struct msdosfsmount *pmp = dep->de_pmp;
732 struct direntry *dentp;
733
734 /*
735 * Since the filesize field in directory entries for a directory is
736 * zero, we just have to feel our way through the directory until
737 * we hit end of file.
738 */
739 for (cn = 0;; cn++) {
740 if ((error = pcbmap(dep, cn, &bn, 0, &blsize)) != 0) {
741 if (error == E2BIG)
742 return (1); /* it's empty */
743 return (0);
744 }
745 error = bread(pmp->pm_devvp, bn, blsize, NOCRED, &bp);
746 if (error) {
747 brelse(bp);
748 return (0);
749 }
750 for (dentp = (struct direntry *)bp->b_data;
751 (char *)dentp < bp->b_data + blsize;
752 dentp++) {
753 if (dentp->deName[0] != SLOT_DELETED &&
754 (dentp->deAttributes & ATTR_VOLUME) == 0) {
755 /*
756 * In dos directories an entry whose name
757 * starts with SLOT_EMPTY (0) starts the
758 * beginning of the unused part of the
759 * directory, so we can just return that it
760 * is empty.
761 */
762 if (dentp->deName[0] == SLOT_EMPTY) {
763 brelse(bp);
764 return (1);
765 }
766 /*
767 * Any names other than "." and ".." in a
768 * directory mean it is not empty.
769 */
770 if (bcmp(dentp->deName, ". ", 11) &&
771 bcmp(dentp->deName, ".. ", 11)) {
772 brelse(bp);
773 #ifdef MSDOSFS_DEBUG
774 printf("dosdirempty(): entry found %02x, %02x\n",
775 dentp->deName[0], dentp->deName[1]);
776 #endif
777 return (0); /* not empty */
778 }
779 }
780 }
781 brelse(bp);
782 }
783 /* NOTREACHED */
784 }
785
786 /*
787 * Check to see if the directory described by target is in some
788 * subdirectory of source. This prevents something like the following from
789 * succeeding and leaving a bunch or files and directories orphaned. mv
790 * /a/b/c /a/b/c/d/e/f Where c and f are directories.
791 *
792 * source - the inode for /a/b/c
793 * target - the inode for /a/b/c/d/e/f
794 *
795 * Returns 0 if target is NOT a subdirectory of source.
796 * Otherwise returns a non-zero error number.
797 * The target inode is always unlocked on return.
798 */
799 int
800 doscheckpath(source, target)
801 struct denode *source;
802 struct denode *target;
803 {
804 uint32_t scn;
805 struct msdosfsmount *pmp;
806 struct direntry *ep;
807 struct denode *dep;
808 struct buf *bp = NULL;
809 int error = 0;
810
811 dep = target;
812 if ((target->de_Attributes & ATTR_DIRECTORY) == 0 ||
813 (source->de_Attributes & ATTR_DIRECTORY) == 0) {
814 error = ENOTDIR;
815 goto out;
816 }
817 if (dep->de_StartCluster == source->de_StartCluster) {
818 error = EEXIST;
819 goto out;
820 }
821 if (dep->de_StartCluster == MSDOSFSROOT)
822 goto out;
823 pmp = dep->de_pmp;
824 #ifdef DIAGNOSTIC
825 if (pmp != source->de_pmp)
826 panic("doscheckpath: source and target on different filesystems");
827 #endif
828 if (FAT32(pmp) && dep->de_StartCluster == pmp->pm_rootdirblk)
829 goto out;
830
831 for (;;) {
832 if ((dep->de_Attributes & ATTR_DIRECTORY) == 0) {
833 error = ENOTDIR;
834 break;
835 }
836 scn = dep->de_StartCluster;
837 error = bread(pmp->pm_devvp, cntobn(pmp, scn),
838 pmp->pm_bpcluster, NOCRED, &bp);
839 if (error)
840 break;
841
842 ep = (struct direntry *) bp->b_data + 1;
843 if ((ep->deAttributes & ATTR_DIRECTORY) == 0 ||
844 bcmp(ep->deName, ".. ", 11) != 0) {
845 error = ENOTDIR;
846 break;
847 }
848 scn = getushort(ep->deStartCluster);
849 if (FAT32(pmp))
850 scn |= getushort(ep->deHighClust) << 16;
851
852 if (scn == source->de_StartCluster) {
853 error = EINVAL;
854 break;
855 }
856 if (scn == MSDOSFSROOT)
857 break;
858 if (FAT32(pmp) && scn == pmp->pm_rootdirblk) {
859 /*
860 * scn should be 0 in this case,
861 * but we silently ignore the error.
862 */
863 break;
864 }
865
866 vput(DETOV(dep));
867 brelse(bp);
868 bp = NULL;
869 /* NOTE: deget() clears dep on error */
870 if ((error = deget(pmp, scn, 0, &dep)) != 0)
871 break;
872 }
873 out:;
874 if (bp)
875 brelse(bp);
876 if (error == ENOTDIR)
877 printf("doscheckpath(): .. not a directory?\n");
878 if (dep != NULL)
879 vput(DETOV(dep));
880 return (error);
881 }
882
883 /*
884 * Read in the disk block containing the directory entry (dirclu, dirofs)
885 * and return the address of the buf header, and the address of the
886 * directory entry within the block.
887 */
888 int
889 readep(pmp, dirclust, diroffset, bpp, epp)
890 struct msdosfsmount *pmp;
891 uint32_t dirclust, diroffset;
892 struct buf **bpp;
893 struct direntry **epp;
894 {
895 int error;
896 daddr64_t bn;
897 int blsize;
898 uint32_t boff;
899
900 boff = diroffset & ~pmp->pm_crbomask;
901 blsize = pmp->pm_bpcluster;
902 if (dirclust == MSDOSFSROOT
903 && de_blk(pmp, diroffset + blsize) > pmp->pm_rootdirsize)
904 blsize = de_bn2off(pmp, pmp->pm_rootdirsize) & pmp->pm_crbomask;
905 bn = detobn(pmp, dirclust, diroffset);
906 if ((error = bread(pmp->pm_devvp, bn, blsize, NOCRED, bpp)) != 0) {
907 brelse(*bpp);
908 *bpp = NULL;
909 return (error);
910 }
911 if (epp)
912 *epp = bptoep(pmp, *bpp, diroffset);
913 return (0);
914 }
915
916 /*
917 * Read in the disk block containing the directory entry dep came from and
918 * return the address of the buf header, and the address of the directory
919 * entry within the block.
920 */
921 int
922 readde(dep, bpp, epp)
923 struct denode *dep;
924 struct buf **bpp;
925 struct direntry **epp;
926 {
927
928 return (readep(dep->de_pmp, dep->de_dirclust, dep->de_diroffset,
929 bpp, epp));
930 }
931
932 /*
933 * Remove a directory entry. At this point the file represented by the
934 * directory entry to be removed is still full length until noone has it
935 * open. When the file no longer being used msdosfs_inactive() is called
936 * and will truncate the file to 0 length. When the vnode containing the
937 * denode is needed for some other purpose by VFS it will call
938 * msdosfs_reclaim() which will remove the denode from the denode cache.
939 */
940 int
941 removede(pdep, dep)
942 struct denode *pdep; /* directory where the entry is removed */
943 struct denode *dep; /* file to be removed */
944 {
945 int error;
946 struct direntry *ep;
947 struct buf *bp;
948 daddr64_t bn;
949 int blsize;
950 struct msdosfsmount *pmp = pdep->de_pmp;
951 uint32_t offset = pdep->de_fndoffset;
952
953 #ifdef MSDOSFS_DEBUG
954 printf("removede(): filename %s, dep %08x, offset %08x\n",
955 dep->de_Name, dep, offset);
956 #endif
957
958 dep->de_refcnt--;
959 offset += sizeof(struct direntry);
960 do {
961 offset -= sizeof(struct direntry);
962 error = pcbmap(pdep, de_cluster(pmp, offset), &bn, 0, &blsize);
963 if (error)
964 return error;
965 error = bread(pmp->pm_devvp, bn, blsize, NOCRED, &bp);
966 if (error) {
967 brelse(bp);
968 return error;
969 }
970 ep = bptoep(pmp, bp, offset);
971 /*
972 * Check whether, if we came here the second time, i.e.
973 * when underflowing into the previous block, the last
974 * entry in this block is a longfilename entry, too.
975 */
976 if (ep->deAttributes != ATTR_WIN95
977 && offset != pdep->de_fndoffset) {
978 brelse(bp);
979 break;
980 }
981 offset += sizeof(struct direntry);
982 while (1) {
983 /*
984 * We are a bit agressive here in that we delete any Win95
985 * entries preceding this entry, not just the ones we "own".
986 * Since these presumably aren't valid anyway,
987 * there should be no harm.
988 */
989 offset -= sizeof(struct direntry);
990 ep--->deName[0] = SLOT_DELETED;
991 if ((pmp->pm_flags & MSDOSFSMNT_NOWIN95)
992 || !(offset & pmp->pm_crbomask)
993 || ep->deAttributes != ATTR_WIN95)
994 break;
995 }
996 if ((error = bwrite(bp)) != 0)
997 return error;
998 } while (!(pmp->pm_flags & MSDOSFSMNT_NOWIN95)
999 && !(offset & pmp->pm_crbomask)
1000 && offset);
1001 return 0;
1002 }
1003
1004 /*
1005 * Create a unique DOS name in dvp
1006 */
1007 int
1008 uniqdosname(dep, cnp, cp)
1009 struct denode *dep;
1010 struct componentname *cnp;
1011 u_char *cp;
1012 {
1013 struct msdosfsmount *pmp = dep->de_pmp;
1014 struct direntry *dentp;
1015 int gen;
1016 int blsize;
1017 uint32_t cn;
1018 daddr64_t bn;
1019 struct buf *bp;
1020 int error;
1021
1022 for (gen = 1;; gen++) {
1023 /*
1024 * Generate DOS name with generation number
1025 */
1026 if (!unix2dosfn((u_char *)cnp->cn_nameptr, cp, cnp->cn_namelen, gen))
1027 return gen == 1 ? EINVAL : EEXIST;
1028
1029 /*
1030 * Now look for a dir entry with this exact name
1031 */
1032 for (cn = error = 0; !error; cn++) {
1033 if ((error = pcbmap(dep, cn, &bn, 0, &blsize)) != 0) {
1034 if (error == E2BIG) /* EOF reached and not found */
1035 return 0;
1036 return error;
1037 }
1038 error = bread(pmp->pm_devvp, bn, blsize, NOCRED, &bp);
1039 if (error) {
1040 brelse(bp);
1041 return error;
1042 }
1043 for (dentp = (struct direntry *)bp->b_data;
1044 (char *)dentp < bp->b_data + blsize;
1045 dentp++) {
1046 if (dentp->deName[0] == SLOT_EMPTY) {
1047 /*
1048 * Last used entry and not found
1049 */
1050 brelse(bp);
1051 return 0;
1052 }
1053 /*
1054 * Ignore volume labels and Win95 entries
1055 */
1056 if (dentp->deAttributes & ATTR_VOLUME)
1057 continue;
1058 if (!bcmp(dentp->deName, cp, 11)) {
1059 error = EEXIST;
1060 break;
1061 }
1062 }
1063 brelse(bp);
1064 }
1065 }
1066
1067 return (EEXIST);
1068 }
1069
1070 /*
1071 * Find any Win'95 long filename entry in directory dep
1072 */
1073 int
1074 findwin95(dep)
1075 struct denode *dep;
1076 {
1077 struct msdosfsmount *pmp = dep->de_pmp;
1078 struct direntry *dentp;
1079 int blsize;
1080 uint32_t cn;
1081 daddr64_t bn;
1082 struct buf *bp;
1083
1084 /*
1085 * Read through the directory looking for Win'95 entries
1086 * Note: Error currently handled just as EOF XXX
1087 */
1088 for (cn = 0;; cn++) {
1089 if (pcbmap(dep, cn, &bn, 0, &blsize))
1090 return 0;
1091 if (bread(pmp->pm_devvp, bn, blsize, NOCRED, &bp)) {
1092 brelse(bp);
1093 return 0;
1094 }
1095 for (dentp = (struct direntry *)bp->b_data;
1096 (char *)dentp < bp->b_data + blsize;
1097 dentp++) {
1098 if (dentp->deName[0] == SLOT_EMPTY) {
1099 /*
1100 * Last used entry and not found
1101 */
1102 brelse(bp);
1103 return 0;
1104 }
1105 if (dentp->deName[0] == SLOT_DELETED) {
1106 /*
1107 * Ignore deleted files
1108 * Note: might be an indication of Win'95 anyway XXX
1109 */
1110 continue;
1111 }
1112 if (dentp->deAttributes == ATTR_WIN95) {
1113 brelse(bp);
1114 return 1;
1115 }
1116 }
1117 brelse(bp);
1118 }
1119 }