1 /* $FreeBSD$ */
2 /* $NetBSD: msdosfs_lookup.c,v 1.37 1997/11/17 15:36:54 ws Exp $ */
3
4 /*-
5 * SPDX-License-Identifier: BSD-4-Clause
6 *
7 * Copyright (C) 1994, 1995, 1997 Wolfgang Solfrank.
8 * Copyright (C) 1994, 1995, 1997 TooLs GmbH.
9 * All rights reserved.
10 * Original code by Paul Popelka (paulp@uts.amdahl.com) (see below).
11 *
12 * Redistribution and use in source and binary forms, with or without
13 * modification, are permitted provided that the following conditions
14 * are met:
15 * 1. Redistributions of source code must retain the above copyright
16 * notice, this list of conditions and the following disclaimer.
17 * 2. Redistributions in binary form must reproduce the above copyright
18 * notice, this list of conditions and the following disclaimer in the
19 * documentation and/or other materials provided with the distribution.
20 * 3. All advertising materials mentioning features or use of this software
21 * must display the following acknowledgement:
22 * This product includes software developed by TooLs GmbH.
23 * 4. The name of TooLs GmbH may not be used to endorse or promote products
24 * derived from this software without specific prior written permission.
25 *
26 * THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``AS IS'' AND ANY EXPRESS OR
27 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
28 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
29 * IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
30 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
31 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
32 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
33 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
34 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
35 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
36 */
37 /*-
38 * Written by Paul Popelka (paulp@uts.amdahl.com)
39 *
40 * You can do anything you want with this software, just don't say you wrote
41 * it, and don't remove this notice.
42 *
43 * This software is provided "as is".
44 *
45 * The author supplies this software to be publicly redistributed on the
46 * understanding that the author is not responsible for the correct
47 * functioning of this software in any circumstances and is not liable for
48 * any damages caused by this software.
49 *
50 * October 1992
51 */
52
53 #include <sys/param.h>
54 #include <sys/systm.h>
55 #include <sys/buf.h>
56 #include <sys/proc.h>
57 #include <sys/mount.h>
58 #include <sys/namei.h>
59 #include <sys/vnode.h>
60
61 #include <sys/buf2.h>
62
63 #include <vfs/msdosfs/bpb.h>
64 #include <vfs/msdosfs/direntry.h>
65 #include <vfs/msdosfs/denode.h>
66 #include <vfs/msdosfs/fat.h>
67 #include <vfs/msdosfs/msdosfsmount.h>
68
69 static int
msdosfs_lookup_checker(struct msdosfsmount * pmp,struct vnode * dvp,struct denode * tdp,struct vnode ** vpp)70 msdosfs_lookup_checker(struct msdosfsmount *pmp, struct vnode *dvp,
71 struct denode *tdp, struct vnode **vpp)
72 {
73 struct vnode *vp;
74
75 vp = DETOV(tdp);
76
77 /*
78 * Lookup assumes that directory cannot be hardlinked.
79 * Corrupted msdosfs filesystem could break this assumption.
80 */
81 if (vp == dvp) {
82 vput(vp);
83 *vpp = NULL;
84 return (EBADF);
85 }
86
87 *vpp = vp;
88 return (0);
89 }
90
91 /*
92 * XXX Implement .vop_nresolve and replace old vnops which depend on this.
93 */
94 /*
95 * When we search a directory the blocks containing directory entries are
96 * read and examined. The directory entries contain information that would
97 * normally be in the inode of a unix filesystem. This means that some of
98 * a directory's contents may also be in memory resident denodes (sort of
99 * an inode). This can cause problems if we are searching while some other
100 * process is modifying a directory. To prevent one process from accessing
101 * incompletely modified directory information we depend upon being the
102 * sole owner of a directory block. bread/brelse provide this service.
103 * This being the case, when a process modifies a directory it must first
104 * acquire the disk block that contains the directory entry to be modified.
105 * Then update the disk block and the denode, and then write the disk block
106 * out to disk. This way disk blocks containing directory entries and in
107 * memory denode's will be in synch.
108 */
109 int
msdosfs_lookup(struct vop_old_lookup_args * ap)110 msdosfs_lookup(struct vop_old_lookup_args *ap)
111 {
112 struct mbnambuf nb;
113 struct vnode *vdp = ap->a_dvp;
114 struct vnode **vpp = ap->a_vpp;
115 struct componentname *cnp = ap->a_cnp;
116 daddr_t bn;
117 int error;
118 int lockparent;
119 int wantparent;
120 int slotcount;
121 int slotoffset = 0;
122 int frcn;
123 u_long cluster;
124 int blkoff;
125 int diroff;
126 int blsize;
127 int isadir; /* ~0 if found direntry is a directory */
128 u_long scn; /* starting cluster number */
129 struct vnode *pdp;
130 struct denode *dp;
131 struct denode *tdp;
132 struct msdosfsmount *pmp;
133 struct buf *bp = NULL;
134 struct direntry *dep = NULL;
135 u_char dosfilename[12];
136 int flags = cnp->cn_flags;
137 int nameiop = cnp->cn_nameiop;
138 int unlen;
139
140 int wincnt = 1;
141 int chksum = -1, chksum_ok;
142 int olddos = 1;
143 cnp->cn_flags &= ~CNP_PDIRUNLOCK;
144
145 mprintf("msdosfs_lookup(): looking for %s\n", cnp->cn_nameptr);
146 dp = VTODE(vdp);
147 pmp = dp->de_pmp;
148 *vpp = NULL;
149 lockparent = flags & CNP_LOCKPARENT;
150 wantparent = flags & (CNP_LOCKPARENT | CNP_WANTPARENT);
151 mprintf("msdosfs_lookup(): vdp %p, dp %p, Attr %02x\n",
152 vdp, dp, dp->de_Attributes);
153
154 /*
155 * If they are going after the . or .. entry in the root directory,
156 * they won't find it. DOS filesystems don't have them in the root
157 * directory. So, we fake it. deget() is in on this scam too.
158 */
159 if ((vdp->v_flag & VROOT) && cnp->cn_nameptr[0] == '.' &&
160 (cnp->cn_namelen == 1 ||
161 (cnp->cn_namelen == 2 && cnp->cn_nameptr[1] == '.'))) {
162 isadir = ATTR_DIRECTORY;
163 scn = MSDOSFSROOT;
164 mprintf("msdosfs_lookup(): looking for . or .. in root directory\n");
165 cluster = MSDOSFSROOT;
166 blkoff = MSDOSFSROOT_OFS;
167 goto foundroot;
168 }
169
170 switch (unix2dosfn((const u_char *)cnp->cn_nameptr, dosfilename,
171 cnp->cn_namelen, 0, pmp)) {
172 case 0:
173 return (EINVAL);
174 case 1:
175 break;
176 case 2:
177 wincnt = winSlotCnt((const u_char *)cnp->cn_nameptr,
178 cnp->cn_namelen, pmp) + 1;
179 break;
180 case 3:
181 olddos = 0;
182 wincnt = winSlotCnt((const u_char *)cnp->cn_nameptr,
183 cnp->cn_namelen, pmp) + 1;
184 break;
185 }
186 if (pmp->pm_flags & MSDOSFSMNT_SHORTNAME) {
187 wincnt = 1;
188 olddos = 1;
189 }
190 unlen = winLenFixup(cnp->cn_nameptr, cnp->cn_namelen);
191
192 /*
193 * Suppress search for slots unless creating
194 * file and at end of pathname, in which case
195 * we watch for a place to put the new file in
196 * case it doesn't already exist.
197 */
198 slotcount = wincnt;
199 if (nameiop == NAMEI_CREATE || nameiop == NAMEI_RENAME)
200 slotcount = 0;
201
202 mprintf("msdosfs_lookup(): dos version of filename %s, length %ld\n",
203 dosfilename, cnp->cn_namelen);
204 /*
205 * Search the directory pointed at by vdp for the name pointed at
206 * by cnp->cn_nameptr.
207 */
208 tdp = NULL;
209 mbnambuf_init(&nb);
210 /*
211 * The outer loop ranges over the clusters that make up the
212 * directory. Note that the root directory is different from all
213 * other directories. It has a fixed number of blocks that are not
214 * part of the pool of allocatable clusters. So, we treat it a
215 * little differently. The root directory starts at "cluster" 0.
216 */
217 diroff = 0;
218 for (frcn = 0;; frcn++) {
219 error = pcbmap(dp, frcn, &bn, &cluster, &blsize);
220 if (error) {
221 if (error == E2BIG)
222 break;
223 return (error);
224 }
225 error = bread(pmp->pm_devvp, de_bn2doff(pmp, bn), blsize, &bp);
226 if (error) {
227 brelse(bp);
228 return (error);
229 }
230 for (blkoff = 0; blkoff < blsize;
231 blkoff += sizeof(struct direntry),
232 diroff += sizeof(struct direntry)) {
233 dep = (struct direntry *)(bp->b_data + blkoff);
234 /*
235 * If the slot is empty and we are still looking
236 * for an empty then remember this one. If the
237 * slot is not empty then check to see if it
238 * matches what we are looking for. If the slot
239 * has never been filled with anything, then the
240 * remainder of the directory has never been used,
241 * so there is no point in searching it.
242 */
243 if (dep->deName[0] == SLOT_EMPTY ||
244 dep->deName[0] == SLOT_DELETED) {
245 /*
246 * Drop memory of previous long matches
247 */
248 chksum = -1;
249 mbnambuf_init(&nb);
250
251 if (slotcount < wincnt) {
252 slotcount++;
253 slotoffset = diroff;
254 }
255 if (dep->deName[0] == SLOT_EMPTY) {
256 brelse(bp);
257 goto notfound;
258 }
259 } else {
260 /*
261 * If there wasn't enough space for our winentries,
262 * forget about the empty space
263 */
264 if (slotcount < wincnt)
265 slotcount = 0;
266
267 /*
268 * Check for Win95 long filename entry
269 */
270 if (dep->deAttributes == ATTR_WIN95) {
271 if (pmp->pm_flags &
272 MSDOSFSMNT_SHORTNAME)
273 continue;
274 chksum = win2unixfn(&nb,
275 (struct winentry *)dep, chksum,
276 pmp);
277 continue;
278 }
279
280 chksum = winChkName(&nb,
281 (const u_char *)cnp->cn_nameptr, unlen,
282 chksum, pmp);
283 if (chksum == -2) {
284 chksum = -1;
285 continue;
286 }
287
288 /*
289 * Ignore volume labels (anywhere, not just
290 * the root directory).
291 */
292 if (dep->deAttributes & ATTR_VOLUME) {
293 chksum = -1;
294 continue;
295 }
296
297 /*
298 * Check for a checksum or name match
299 */
300 chksum_ok = (chksum == winChksum(dep->deName));
301 if (!chksum_ok
302 && (!olddos || memcmp(dosfilename,
303 dep->deName, 11))) {
304 chksum = -1;
305 continue;
306 }
307 mprintf("msdosfs_lookup(): match blkoff %d, diroff %d\n",
308 blkoff, diroff);
309 /*
310 * Remember where this directory
311 * entry came from for whoever did
312 * this lookup.
313 */
314 dp->de_fndoffset = diroff;
315 if (chksum_ok && nameiop == NAMEI_RENAME) {
316 /*
317 * Target had correct long name
318 * directory entries, reuse them
319 * as needed.
320 */
321 dp->de_fndcnt = wincnt - 1;
322 } else {
323 /*
324 * Long name directory entries
325 * not present or corrupt, can only
326 * reuse dos directory entry.
327 */
328 dp->de_fndcnt = 0;
329 }
330
331 goto found;
332 }
333 } /* for (blkoff = 0; .... */
334 /*
335 * Release the buffer holding the directory cluster just
336 * searched.
337 */
338 brelse(bp);
339 } /* for (frcn = 0; ; frcn++) */
340
341 notfound:
342 /*
343 * We hold no disk buffers at this point.
344 */
345
346 /*
347 * Fixup the slot description to point to the place where
348 * we might put the new DOS direntry (putting the Win95
349 * long name entries before that)
350 */
351 if (!slotcount) {
352 slotcount = 1;
353 slotoffset = diroff;
354 }
355 if (wincnt > slotcount)
356 slotoffset += sizeof(struct direntry) * (wincnt - slotcount);
357
358 /*
359 * If we get here we didn't find the entry we were looking for. But
360 * that's ok if we are creating or renaming and are at the end of
361 * the pathname and the directory hasn't been removed.
362 */
363 mprintf("msdosfs_lookup(): op %d, refcnt %ld\n",
364 nameiop, dp->de_refcnt);
365 mprintf(" slotcount %d, slotoffset %d\n",
366 slotcount, slotoffset);
367 if ((nameiop == NAMEI_CREATE || nameiop == NAMEI_RENAME) &&
368 dp->de_refcnt > 0) {
369 /*
370 * Access for write is interpreted as allowing
371 * creation of files in the directory.
372 */
373 error = VOP_EACCESS(vdp, VWRITE, cnp->cn_cred);
374 if (error)
375 return (error);
376 /*
377 * Return an indication of where the new directory
378 * entry should be put.
379 */
380 dp->de_fndoffset = slotoffset;
381 dp->de_fndcnt = wincnt - 1;
382
383 /*
384 * We return with the directory locked, so that
385 * the parameters we set up above will still be
386 * valid if we actually decide to do a direnter().
387 * We return ni_vp == NULL to indicate that the entry
388 * does not currently exist; we leave a pointer to
389 * the (locked) directory inode in ndp->ni_dvp.
390 * The pathname buffer is saved so that the name
391 * can be obtained later.
392 *
393 * NB - if the directory is unlocked, then this
394 * information cannot be used.
395 */
396 if (!lockparent) {
397 vn_unlock(vdp);
398 cnp->cn_flags |= CNP_PDIRUNLOCK;
399 }
400 return (EJUSTRETURN);
401 }
402 return (ENOENT);
403
404 found:
405 /*
406 * NOTE: We still have the buffer with matched directory entry at
407 * this point.
408 */
409 isadir = dep->deAttributes & ATTR_DIRECTORY;
410 scn = getushort(dep->deStartCluster);
411 if (FAT32(pmp)) {
412 scn |= getushort(dep->deHighClust) << 16;
413 if (scn == pmp->pm_rootdirblk) {
414 /*
415 * There should actually be 0 here.
416 * Just ignore the error.
417 */
418 scn = MSDOSFSROOT;
419 }
420 }
421
422 if (isadir) {
423 cluster = scn;
424 if (cluster == MSDOSFSROOT)
425 blkoff = MSDOSFSROOT_OFS;
426 else
427 blkoff = 0;
428 } else if (cluster == MSDOSFSROOT)
429 blkoff = diroff;
430
431 /*
432 * Now release buf to allow deget to read the entry again.
433 * Reserving it here and giving it to deget could result
434 * in a deadlock.
435 */
436 brelse(bp);
437 bp = NULL;
438
439 foundroot:
440 /*
441 * If we entered at foundroot, then we are looking for the . or ..
442 * entry of the filesystems root directory. isadir and scn were
443 * setup before jumping here. And, bp is already null.
444 */
445 if (FAT32(pmp) && scn == MSDOSFSROOT)
446 scn = pmp->pm_rootdirblk;
447
448 /*
449 * If deleting, and at end of pathname, return
450 * parameters which can be used to remove file.
451 * If the wantparent flag isn't set, we return only
452 * the directory (in ndp->ni_dvp), otherwise we go
453 * on and lock the inode, being careful with ".".
454 */
455 if (nameiop == NAMEI_DELETE) {
456 /*
457 * Don't allow deleting the root.
458 */
459 if (blkoff == MSDOSFSROOT_OFS)
460 return (EBUSY);
461
462 /*
463 * Write access to directory required to delete files.
464 */
465 error = VOP_EACCESS(vdp, VWRITE, cnp->cn_cred);
466 if (error)
467 return (error);
468
469 /*
470 * Return pointer to current entry in dp->i_offset.
471 * Save directory inode pointer in ndp->ni_dvp for dirremove().
472 */
473 if (dp->de_StartCluster == scn && isadir) { /* "." */
474 vref(vdp);
475 *vpp = vdp;
476 return (0);
477 }
478 error = deget(pmp, cluster, blkoff, &tdp);
479 if (error)
480 return (error);
481 error = msdosfs_lookup_checker(pmp, vdp, tdp, vpp);
482 if (!lockparent) {
483 vn_unlock(vdp);
484 cnp->cn_flags |= CNP_PDIRUNLOCK;
485 }
486 return (error);
487 }
488
489 /*
490 * If rewriting (RENAME), return the inode and the
491 * information required to rewrite the present directory
492 * Must get inode of directory entry to verify it's a
493 * regular file, or empty directory.
494 */
495 if (nameiop == NAMEI_RENAME && wantparent) {
496 if (blkoff == MSDOSFSROOT_OFS)
497 return (EBUSY);
498
499 error = VOP_EACCESS(vdp, VWRITE, cnp->cn_cred);
500 if (error)
501 return (error);
502
503 /*
504 * Careful about locking second inode.
505 * This can only occur if the target is ".".
506 */
507 if (dp->de_StartCluster == scn && isadir)
508 return (EISDIR);
509
510 if ((error = deget(pmp, cluster, blkoff, &tdp)) != 0)
511 return (error);
512 error = msdosfs_lookup_checker(pmp, vdp, tdp, vpp);
513 if (!lockparent) {
514 vn_unlock(vdp);
515 cnp->cn_flags |= CNP_PDIRUNLOCK;
516 }
517 return (error);
518 }
519
520 /*
521 * Step through the translation in the name. We do not `vput' the
522 * directory because we may need it again if a symbolic link
523 * is relative to the current directory. Instead we save it
524 * unlocked as "pdp". We must get the target inode before unlocking
525 * the directory to insure that the inode will not be removed
526 * before we get it. We prevent deadlock by always fetching
527 * inodes from the root, moving down the directory tree. Thus
528 * when following backward pointers ".." we must unlock the
529 * parent directory before getting the requested directory.
530 * There is a potential race condition here if both the current
531 * and parent directories are removed before the VFS_VGET for the
532 * inode associated with ".." returns. We hope that this occurs
533 * infrequently since we cannot avoid this race condition without
534 * implementing a sophisticated deadlock detection algorithm.
535 * Note also that this simple deadlock detection scheme will not
536 * work if the file system has any hard links other than ".."
537 * that point backwards in the directory structure.
538 */
539 pdp = vdp;
540 if (flags & CNP_ISDOTDOT) {
541 vn_unlock(pdp);
542 cnp->cn_flags |= CNP_PDIRUNLOCK;
543 error = deget(pmp, cluster, blkoff, &tdp);
544 if (error) {
545 vn_lock(pdp, LK_EXCLUSIVE | LK_RETRY);
546 cnp->cn_flags &= ~CNP_PDIRUNLOCK;
547 return (error);
548 }
549 if (lockparent) {
550 error = vn_lock(pdp, LK_EXCLUSIVE | LK_FAILRECLAIM);
551 if (error) {
552 vput(DETOV(tdp));
553 return (error);
554 }
555 cnp->cn_flags &= ~CNP_PDIRUNLOCK;
556 }
557 error = msdosfs_lookup_checker(pmp, vdp, VTODE(*vpp), vpp);
558 if (error != 0)
559 return (error);
560 } else if (dp->de_StartCluster == scn && isadir) {
561 if (cnp->cn_namelen != 1 || cnp->cn_nameptr[0] != '.') {
562 /* fs is corrupted, non-dot lookup returned dvp */
563 return (EBADF);
564 }
565 vref(vdp); /* we want ourself, ie "." */
566 *vpp = vdp;
567 } else {
568 if ((error = deget(pmp, cluster, blkoff, &tdp)) != 0)
569 return (error);
570 if (!lockparent) {
571 vn_unlock(pdp);
572 cnp->cn_flags |= CNP_PDIRUNLOCK;
573 }
574 error = msdosfs_lookup_checker(pmp, vdp, tdp, vpp);
575 if (error != 0)
576 return (error);
577 }
578 return (0);
579 }
580
581 /*
582 * dep - directory entry to copy into the directory
583 * ddep - directory to add to
584 * depp - return the address of the denode for the created directory entry
585 * if depp != 0
586 * cnp - componentname needed for Win95 long filenames
587 */
588 int
createde(struct denode * dep,struct denode * ddep,struct denode ** depp,struct componentname * cnp)589 createde(struct denode *dep, struct denode *ddep, struct denode **depp,
590 struct componentname *cnp)
591 {
592 int error;
593 u_long dirclust, diroffset;
594 struct direntry *ndep;
595 struct msdosfsmount *pmp = ddep->de_pmp;
596 struct buf *bp;
597 daddr_t bn;
598 int blsize;
599
600 mprintf("createde(dep %p, ddep %p, depp %p, cnp %p)\n",
601 dep, ddep, depp, cnp);
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 detrunc(ddep, ddep->de_FileSize, 0);
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 error = bread(pmp->pm_devvp, de_bn2doff(pmp, bn), blsize, &bp);
640 if (error != 0) {
641 brelse(bp);
642 return error;
643 }
644 ndep = bptoep(pmp, bp, ddep->de_fndoffset);
645
646 DE_EXTERNALIZE(ndep, dep);
647
648 /*
649 * Now write the Win95 long name
650 */
651 if (ddep->de_fndcnt > 0) {
652 uint8_t chksum = winChksum(ndep->deName);
653 const u_char *un = (const u_char *)cnp->cn_nameptr;
654 int unlen = cnp->cn_namelen;
655 int cnt = 1;
656
657 while (--ddep->de_fndcnt >= 0) {
658 if (!(ddep->de_fndoffset & pmp->pm_crbomask)) {
659 if (DOINGASYNC(DETOV(ddep)))
660 bdwrite(bp);
661 else if ((error = bwrite(bp)) != 0)
662 return error;
663
664 ddep->de_fndoffset -= sizeof(struct direntry);
665 error = pcbmap(ddep,
666 de_cluster(pmp,
667 ddep->de_fndoffset),
668 &bn, NULL, &blsize);
669 if (error)
670 return error;
671
672 error = bread(pmp->pm_devvp,
673 de_bn2doff(pmp, bn), blsize,
674 &bp);
675 if (error) {
676 brelse(bp);
677 return error;
678 }
679 ndep = bptoep(pmp, bp, ddep->de_fndoffset);
680 } else {
681 ndep--;
682 ddep->de_fndoffset -= sizeof(struct direntry);
683 }
684 if (!unix2winfn(un, unlen, (struct winentry *)ndep,
685 cnt++, chksum, pmp))
686 break;
687 }
688 }
689
690 if (DOINGASYNC(DETOV(ddep)))
691 bdwrite(bp);
692 else if ((error = bwrite(bp)) != 0)
693 return error;
694
695 /*
696 * If they want us to return with the denode gotten.
697 */
698 if (depp) {
699 if (dep->de_Attributes & ATTR_DIRECTORY) {
700 dirclust = dep->de_StartCluster;
701 if (FAT32(pmp) && dirclust == pmp->pm_rootdirblk)
702 dirclust = MSDOSFSROOT;
703 if (dirclust == MSDOSFSROOT)
704 diroffset = MSDOSFSROOT_OFS;
705 else
706 diroffset = 0;
707 }
708 return deget(pmp, dirclust, diroffset, depp);
709 }
710
711 return 0;
712 }
713
714 /*
715 * Be sure a directory is empty except for "." and "..". Return 1 if empty,
716 * return 0 if not empty or error.
717 */
718 int
dosdirempty(struct denode * dep)719 dosdirempty(struct denode *dep)
720 {
721 int blsize;
722 int error;
723 u_long cn;
724 daddr_t bn;
725 struct buf *bp;
726 struct msdosfsmount *pmp = dep->de_pmp;
727 struct direntry *dentp;
728
729 /*
730 * Since the filesize field in directory entries for a directory is
731 * zero, we just have to feel our way through the directory until
732 * we hit end of file.
733 */
734 for (cn = 0;; cn++) {
735 if ((error = pcbmap(dep, cn, &bn, NULL, &blsize)) != 0) {
736 if (error == E2BIG)
737 return (1); /* it's empty */
738 return (0);
739 }
740 error = bread(pmp->pm_devvp, de_bn2doff(pmp, bn), blsize, &bp);
741 if (error) {
742 brelse(bp);
743 return (0);
744 }
745 for (dentp = (struct direntry *)bp->b_data;
746 (char *)dentp < bp->b_data + blsize;
747 dentp++) {
748 if (dentp->deName[0] != SLOT_DELETED &&
749 (dentp->deAttributes & ATTR_VOLUME) == 0) {
750 /*
751 * In dos directories an entry whose name
752 * starts with SLOT_EMPTY (0) starts the
753 * beginning of the unused part of the
754 * directory, so we can just return that it
755 * is empty.
756 */
757 if (dentp->deName[0] == SLOT_EMPTY) {
758 brelse(bp);
759 return (1);
760 }
761 /*
762 * Any names other than "." and ".." in a
763 * directory mean it is not empty.
764 */
765 if (memcmp(dentp->deName, ". ", 11) &&
766 memcmp(dentp->deName, ".. ", 11)) {
767 brelse(bp);
768 mprintf("dosdirempty(): entry found %02x, %02x\n",
769 dentp->deName[0], dentp->deName[1]);
770 return (0); /* not empty */
771 }
772 }
773 }
774 brelse(bp);
775 }
776 /* NOTREACHED */
777 }
778
779 /*
780 * Check to see if the directory described by target is in some
781 * subdirectory of source. This prevents something like the following from
782 * succeeding and leaving a bunch or files and directories orphaned. mv
783 * /a/b/c /a/b/c/d/e/f Where c and f are directories.
784 *
785 * source - the inode for /a/b/c
786 * target - the inode for /a/b/c/d/e/f
787 *
788 * Returns 0 if target is NOT a subdirectory of source.
789 * Otherwise returns a non-zero error number.
790 * The target inode is always unlocked on return.
791 */
792 int
doscheckpath(struct denode * source,struct denode * target)793 doscheckpath(struct denode *source, struct denode *target)
794 {
795 daddr_t scn;
796 struct msdosfsmount *pmp;
797 struct direntry *ep;
798 struct denode *dep;
799 struct buf *bp = NULL;
800 int error = 0;
801
802 dep = target;
803 if ((target->de_Attributes & ATTR_DIRECTORY) == 0 ||
804 (source->de_Attributes & ATTR_DIRECTORY) == 0) {
805 error = ENOTDIR;
806 goto out;
807 }
808 if (dep->de_StartCluster == source->de_StartCluster) {
809 error = EEXIST;
810 goto out;
811 }
812 if (dep->de_StartCluster == MSDOSFSROOT)
813 goto out;
814 pmp = dep->de_pmp;
815 #ifdef DIAGNOSTIC
816 if (pmp != source->de_pmp)
817 panic("doscheckpath: source and target on different filesystems");
818 #endif
819 if (FAT32(pmp) && dep->de_StartCluster == pmp->pm_rootdirblk)
820 goto out;
821
822 for (;;) {
823 if ((dep->de_Attributes & ATTR_DIRECTORY) == 0) {
824 error = ENOTDIR;
825 break;
826 }
827 scn = dep->de_StartCluster;
828 error = bread(pmp->pm_devvp, de_bn2doff(pmp, cntobn(pmp, scn)),
829 pmp->pm_bpcluster, &bp);
830 if (error)
831 break;
832
833 ep = (struct direntry *) bp->b_data + 1;
834 if ((ep->deAttributes & ATTR_DIRECTORY) == 0 ||
835 memcmp(ep->deName, ".. ", 11) != 0) {
836 error = ENOTDIR;
837 break;
838 }
839 scn = getushort(ep->deStartCluster);
840 if (FAT32(pmp))
841 scn |= getushort(ep->deHighClust) << 16;
842
843 if (scn == source->de_StartCluster) {
844 error = EINVAL;
845 break;
846 }
847 if (scn == MSDOSFSROOT)
848 break;
849 if (FAT32(pmp) && scn == pmp->pm_rootdirblk) {
850 /*
851 * scn should be 0 in this case,
852 * but we silently ignore the error.
853 */
854 break;
855 }
856
857 vput(DETOV(dep));
858 brelse(bp);
859 bp = NULL;
860 /* NOTE: deget() clears dep on error */
861 if ((error = deget(pmp, scn, 0, &dep)) != 0)
862 break;
863 }
864 out:
865 if (bp)
866 brelse(bp);
867 if (error == ENOTDIR)
868 kprintf("doscheckpath(): .. not a directory?\n");
869 if (dep != NULL)
870 vput(DETOV(dep));
871 return (error);
872 }
873
874 /*
875 * Read in the disk block containing the directory entry (dirclu, dirofs)
876 * and return the address of the buf header, and the address of the
877 * directory entry within the block.
878 */
879 int
readep(struct msdosfsmount * pmp,u_long dirclust,u_long diroffset,struct buf ** bpp,struct direntry ** epp)880 readep(struct msdosfsmount *pmp, u_long dirclust, u_long diroffset,
881 struct buf **bpp, struct direntry **epp)
882 {
883 int error;
884 daddr_t bn;
885 int blsize;
886
887 blsize = pmp->pm_bpcluster;
888 if (dirclust == MSDOSFSROOT
889 && de_blk(pmp, diroffset + blsize) > pmp->pm_rootdirsize)
890 blsize = de_bn2off(pmp, pmp->pm_rootdirsize) & pmp->pm_crbomask;
891 bn = detobn(pmp, dirclust, diroffset);
892 error = bread(pmp->pm_devvp, de_bn2doff(pmp, bn), blsize, bpp);
893 if (error != 0) {
894 brelse(*bpp);
895 *bpp = NULL;
896 return (error);
897 }
898 if (epp)
899 *epp = bptoep(pmp, *bpp, diroffset);
900 return (0);
901 }
902
903 /*
904 * Read in the disk block containing the directory entry dep came from and
905 * return the address of the buf header, and the address of the directory
906 * entry within the block.
907 */
908 int
readde(struct denode * dep,struct buf ** bpp,struct direntry ** epp)909 readde(struct denode *dep, struct buf **bpp, struct direntry **epp)
910 {
911 return (readep(dep->de_pmp, dep->de_dirclust, dep->de_diroffset,
912 bpp, epp));
913 }
914
915 /*
916 * Remove a directory entry. At this point the file represented by the
917 * directory entry to be removed is still full length until no one has it
918 * open. When the file no longer being used msdosfs_inactive() is called
919 * and will truncate the file to 0 length. When the vnode containing the
920 * denode is needed for some other purpose by VFS it will call
921 * msdosfs_reclaim() which will remove the denode from the denode cache.
922 *
923 * pdep directory where the entry is removed
924 * dep file to be removed
925 */
926 int
removede(struct denode * pdep,struct denode * dep)927 removede(struct denode *pdep, struct denode *dep)
928 {
929 int error;
930 struct direntry *ep;
931 struct buf *bp;
932 daddr_t bn;
933 int blsize;
934 struct msdosfsmount *pmp = pdep->de_pmp;
935 u_long offset = pdep->de_fndoffset;
936
937 mprintf("removede(): filename %s, dep %p, offset %08lx\n",
938 dep->de_Name, dep, offset);
939
940 KKASSERT(dep->de_refcnt > 0);
941 dep->de_refcnt--;
942 offset += sizeof(struct direntry);
943 do {
944 offset -= sizeof(struct direntry);
945 error = pcbmap(pdep, de_cluster(pmp, offset),
946 &bn, NULL, &blsize);
947 if (error)
948 return error;
949 error = bread(pmp->pm_devvp, de_bn2doff(pmp, bn), blsize, &bp);
950 if (error) {
951 brelse(bp);
952 return error;
953 }
954 ep = bptoep(pmp, bp, offset);
955 /*
956 * Check whether, if we came here the second time, i.e.
957 * when underflowing into the previous block, the last
958 * entry in this block is a longfilename entry, too.
959 */
960 if (ep->deAttributes != ATTR_WIN95
961 && offset != pdep->de_fndoffset) {
962 brelse(bp);
963 break;
964 }
965 offset += sizeof(struct direntry);
966 while (1) {
967 /*
968 * We are a bit aggressive here in that we delete any Win95
969 * entries preceding this entry, not just the ones we "own".
970 * Since these presumably aren't valid anyway,
971 * there should be no harm.
972 */
973 offset -= sizeof(struct direntry);
974 ep--->deName[0] = SLOT_DELETED;
975 if ((pmp->pm_flags & MSDOSFSMNT_NOWIN95)
976 || !(offset & pmp->pm_crbomask)
977 || ep->deAttributes != ATTR_WIN95)
978 break;
979 }
980 if (DOINGASYNC(DETOV(pdep)))
981 bdwrite(bp);
982 else if ((error = bwrite(bp)) != 0)
983 return error;
984 } while (!(pmp->pm_flags & MSDOSFSMNT_NOWIN95)
985 && !(offset & pmp->pm_crbomask)
986 && offset);
987 return 0;
988 }
989
990 /*
991 * Create a unique DOS name in dvp
992 */
993 int
uniqdosname(struct denode * dep,struct componentname * cnp,u_char * cp)994 uniqdosname(struct denode *dep, struct componentname *cnp, u_char *cp)
995 {
996 struct msdosfsmount *pmp = dep->de_pmp;
997 struct direntry *dentp;
998 int gen;
999 int blsize;
1000 u_long cn;
1001 daddr_t bn;
1002 struct buf *bp;
1003 int error;
1004
1005 if (pmp->pm_flags & MSDOSFSMNT_SHORTNAME)
1006 return (unix2dosfn((const u_char *)cnp->cn_nameptr, cp,
1007 cnp->cn_namelen, 0, pmp) ? 0 : EINVAL);
1008
1009 for (gen = 1;; gen++) {
1010 /*
1011 * Generate DOS name with generation number
1012 */
1013 if (!unix2dosfn((const u_char *)cnp->cn_nameptr, cp,
1014 cnp->cn_namelen, gen, pmp))
1015 return gen == 1 ? EINVAL : EEXIST;
1016
1017 /*
1018 * Now look for a dir entry with this exact name
1019 */
1020 for (cn = error = 0; !error; cn++) {
1021 if ((error = pcbmap(dep, cn, &bn, 0, &blsize)) != 0) {
1022 if (error == E2BIG) /* EOF reached and not found */
1023 return 0;
1024 return error;
1025 }
1026 error = bread(pmp->pm_devvp, de_bn2doff(pmp, bn),
1027 blsize, &bp);
1028 if (error) {
1029 brelse(bp);
1030 return error;
1031 }
1032 for (dentp = (struct direntry *)bp->b_data;
1033 (char *)dentp < bp->b_data + blsize;
1034 dentp++) {
1035 if (dentp->deName[0] == SLOT_EMPTY) {
1036 /*
1037 * Last used entry and not found
1038 */
1039 brelse(bp);
1040 return 0;
1041 }
1042 /*
1043 * Ignore volume labels and Win95 entries
1044 */
1045 if (dentp->deAttributes & ATTR_VOLUME)
1046 continue;
1047 if (!memcmp(dentp->deName, cp, 11)) {
1048 error = EEXIST;
1049 break;
1050 }
1051 }
1052 brelse(bp);
1053 }
1054 }
1055 }
1056