1 /*
2 * Copyright (c) 1989, 1993
3 * The Regents of the University of California. All rights reserved.
4 * (c) UNIX System Laboratories, Inc.
5 * All or some portions of this file are derived from material licensed
6 * to the University of California by American Telephone and Telegraph
7 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
8 * the permission of UNIX System Laboratories, Inc.
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 the University of
21 * California, Berkeley and its contributors.
22 * 4. Neither the name of the University nor the names of its contributors
23 * may be used to endorse or promote products derived from this software
24 * without specific prior written permission.
25 *
26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36 * SUCH DAMAGE.
37 *
38 * @(#)ufs_lookup.c 8.15 (Berkeley) 6/16/95
39 * $FreeBSD$
40 */
41
42 #include "opt_ufs.h"
43
44 #include <sys/param.h>
45 #include <sys/systm.h>
46 #include <sys/kernel.h>
47 #include <sys/namei.h>
48 #include <sys/buf.h>
49 #include <sys/proc.h>
50 #include <sys/stat.h>
51 #include <sys/mount.h>
52 #include <sys/vnode.h>
53 #include <sys/sysctl.h>
54
55 #include <vm/vm.h>
56 #include <vm/vm_extern.h>
57
58 #include <ufs/ufs/quota.h>
59 #include <ufs/ufs/inode.h>
60 #include <ufs/ufs/dir.h>
61 #ifdef UFS_DIRHASH
62 #include <ufs/ufs/dirhash.h>
63 #endif
64 #include <ufs/ufs/ufsmount.h>
65 #include <ufs/ufs/ufs_extern.h>
66
67 #ifdef DIAGNOSTIC
68 int dirchk = 1;
69 #else
70 int dirchk = 0;
71 #endif
72
73 SYSCTL_INT(_debug, OID_AUTO, dircheck, CTLFLAG_RW, &dirchk, 0, "");
74
75 /* true if old FS format...*/
76 #define OFSFMT(vp) ((vp)->v_mount->mnt_maxsymlinklen <= 0)
77
78 /*
79 * Convert a component of a pathname into a pointer to a locked inode.
80 * This is a very central and rather complicated routine.
81 * If the file system is not maintained in a strict tree hierarchy,
82 * this can result in a deadlock situation (see comments in code below).
83 *
84 * The cnp->cn_nameiop argument is LOOKUP, CREATE, RENAME, or DELETE depending
85 * on whether the name is to be looked up, created, renamed, or deleted.
86 * When CREATE, RENAME, or DELETE is specified, information usable in
87 * creating, renaming, or deleting a directory entry may be calculated.
88 * If flag has LOCKPARENT or'ed into it and the target of the pathname
89 * exists, lookup returns both the target and its parent directory locked.
90 * When creating or renaming and LOCKPARENT is specified, the target may
91 * not be ".". When deleting and LOCKPARENT is specified, the target may
92 * be "."., but the caller must check to ensure it does an vrele and vput
93 * instead of two vputs.
94 *
95 * This routine is actually used as VOP_CACHEDLOOKUP method, and the
96 * filesystem employs the generic vfs_cache_lookup() as VOP_LOOKUP
97 * method.
98 *
99 * vfs_cache_lookup() performs the following for us:
100 * check that it is a directory
101 * check accessibility of directory
102 * check for modification attempts on read-only mounts
103 * if name found in cache
104 * if at end of path and deleting or creating
105 * drop it
106 * else
107 * return name.
108 * return VOP_CACHEDLOOKUP()
109 *
110 * Overall outline of ufs_lookup:
111 *
112 * search for name in directory, to found or notfound
113 * notfound:
114 * if creating, return locked directory, leaving info on available slots
115 * else return error
116 * found:
117 * if at end of path and deleting, return information to allow delete
118 * if at end of path and rewriting (RENAME and LOCKPARENT), lock target
119 * inode and return info to allow rewrite
120 * if not at end, add name to cache; if at end and neither creating
121 * nor deleting, add name to cache
122 */
123 int
124 ufs_lookup(ap)
125 struct vop_cachedlookup_args /* {
126 struct vnode *a_dvp;
127 struct vnode **a_vpp;
128 struct componentname *a_cnp;
129 } */ *ap;
130 {
131 register struct vnode *vdp; /* vnode for directory being searched */
132 register struct inode *dp; /* inode for directory being searched */
133 struct buf *bp; /* a buffer of directory entries */
134 struct direct *ep; /* the current directory entry */
135 int entryoffsetinblock; /* offset of ep in bp's buffer */
136 enum {NONE, COMPACT, FOUND} slotstatus;
137 doff_t slotoffset; /* offset of area with free space */
138 int slotsize; /* size of area at slotoffset */
139 int slotfreespace; /* amount of space free in slot */
140 int slotneeded; /* size of the entry we're seeking */
141 int numdirpasses; /* strategy for directory search */
142 doff_t endsearch; /* offset to end directory search */
143 doff_t prevoff; /* prev entry dp->i_offset */
144 struct vnode *pdp; /* saved dp during symlink work */
145 struct vnode *tdp; /* returned by VFS_VGET */
146 doff_t enduseful; /* pointer past last used dir slot */
147 u_long bmask; /* block offset mask */
148 int lockparent; /* 1 => lockparent flag is set */
149 int wantparent; /* 1 => wantparent or lockparent flag */
150 int namlen, error;
151 struct vnode **vpp = ap->a_vpp;
152 struct componentname *cnp = ap->a_cnp;
153 struct ucred *cred = cnp->cn_cred;
154 int flags = cnp->cn_flags;
155 int nameiop = cnp->cn_nameiop;
156 struct proc *p = cnp->cn_proc;
157
158 bp = NULL;
159 slotoffset = -1;
160 cnp->cn_flags &= ~PDIRUNLOCK;
161 /*
162 * XXX there was a soft-update diff about this I couldn't merge.
163 * I think this was the equiv.
164 */
165 *vpp = NULL;
166
167 vdp = ap->a_dvp;
168 dp = VTOI(vdp);
169 lockparent = flags & LOCKPARENT;
170 wantparent = flags & (LOCKPARENT|WANTPARENT);
171
172 /*
173 * We now have a segment name to search for, and a directory to search.
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 slotstatus = FOUND;
181 slotfreespace = slotsize = slotneeded = 0;
182 if ((nameiop == CREATE || nameiop == RENAME) &&
183 (flags & ISLASTCN)) {
184 slotstatus = NONE;
185 slotneeded = DIRECTSIZ(cnp->cn_namelen);
186 }
187 bmask = VFSTOUFS(vdp->v_mount)->um_mountp->mnt_stat.f_iosize - 1;
188
189 #ifdef UFS_DIRHASH
190 /*
191 * Use dirhash for fast operations on large directories. The logic
192 * to determine whether to hash the directory is contained within
193 * ufsdirhash_build(); a zero return means that it decided to hash
194 * this directory and it successfully built up the hash table.
195 */
196 if (ufsdirhash_build(dp) == 0) {
197 /* Look for a free slot if needed. */
198 enduseful = dp->i_size;
199 if (slotstatus != FOUND) {
200 slotoffset = ufsdirhash_findfree(dp, slotneeded,
201 &slotsize);
202 if (slotoffset >= 0) {
203 slotstatus = COMPACT;
204 enduseful = ufsdirhash_enduseful(dp);
205 if (enduseful < 0)
206 enduseful = dp->i_size;
207 }
208 }
209 /* Look up the component. */
210 numdirpasses = 1;
211 entryoffsetinblock = 0; /* silence compiler warning */
212 switch (ufsdirhash_lookup(dp, cnp->cn_nameptr, cnp->cn_namelen,
213 &dp->i_offset, &bp, nameiop == DELETE ? &prevoff : NULL)) {
214 case 0:
215 ep = (struct direct *)((char *)bp->b_data +
216 (dp->i_offset & bmask));
217 goto foundentry;
218 case ENOENT:
219 dp->i_offset = roundup2(dp->i_size, DIRBLKSIZ);
220 goto notfound;
221 default:
222 /* Something failed; just do a linear search. */
223 break;
224 }
225 }
226 #endif /* UFS_DIRHASH */
227 /*
228 * If there is cached information on a previous search of
229 * this directory, pick up where we last left off.
230 * We cache only lookups as these are the most common
231 * and have the greatest payoff. Caching CREATE has little
232 * benefit as it usually must search the entire directory
233 * to determine that the entry does not exist. Caching the
234 * location of the last DELETE or RENAME has not reduced
235 * profiling time and hence has been removed in the interest
236 * of simplicity.
237 */
238 if (nameiop != LOOKUP || dp->i_diroff == 0 ||
239 dp->i_diroff >= dp->i_size) {
240 entryoffsetinblock = 0;
241 dp->i_offset = 0;
242 numdirpasses = 1;
243 } else {
244 dp->i_offset = dp->i_diroff;
245 if ((entryoffsetinblock = dp->i_offset & bmask) &&
246 (error = UFS_BLKATOFF(vdp, (off_t)dp->i_offset, NULL, &bp)))
247 return (error);
248 numdirpasses = 2;
249 nchstats.ncs_2passes++;
250 }
251 prevoff = dp->i_offset;
252 endsearch = roundup2(dp->i_size, DIRBLKSIZ);
253 enduseful = 0;
254
255 searchloop:
256 while (dp->i_offset < endsearch) {
257 /*
258 * If necessary, get the next directory block.
259 */
260 if ((dp->i_offset & bmask) == 0) {
261 if (bp != NULL)
262 brelse(bp);
263 error =
264 UFS_BLKATOFF(vdp, (off_t)dp->i_offset, NULL, &bp);
265 if (error)
266 return (error);
267 entryoffsetinblock = 0;
268 }
269 /*
270 * If still looking for a slot, and at a DIRBLKSIZE
271 * boundary, have to start looking for free space again.
272 */
273 if (slotstatus == NONE &&
274 (entryoffsetinblock & (DIRBLKSIZ - 1)) == 0) {
275 slotoffset = -1;
276 slotfreespace = 0;
277 }
278 /*
279 * Get pointer to next entry.
280 * Full validation checks are slow, so we only check
281 * enough to insure forward progress through the
282 * directory. Complete checks can be run by patching
283 * "dirchk" to be true.
284 */
285 ep = (struct direct *)((char *)bp->b_data + entryoffsetinblock);
286 if (ep->d_reclen == 0 || ep->d_reclen >
287 DIRBLKSIZ - (entryoffsetinblock & (DIRBLKSIZ - 1)) ||
288 (dirchk && ufs_dirbadentry(vdp, ep, entryoffsetinblock))) {
289 int i;
290
291 ufs_dirbad(dp, dp->i_offset, "mangled entry");
292 i = DIRBLKSIZ - (entryoffsetinblock & (DIRBLKSIZ - 1));
293 dp->i_offset += i;
294 entryoffsetinblock += i;
295 continue;
296 }
297
298 /*
299 * If an appropriate sized slot has not yet been found,
300 * check to see if one is available. Also accumulate space
301 * in the current block so that we can determine if
302 * compaction is viable.
303 */
304 if (slotstatus != FOUND) {
305 int size = ep->d_reclen;
306
307 if (ep->d_ino != 0)
308 size -= DIRSIZ(OFSFMT(vdp), ep);
309 if (size > 0) {
310 if (size >= slotneeded) {
311 slotstatus = FOUND;
312 slotoffset = dp->i_offset;
313 slotsize = ep->d_reclen;
314 } else if (slotstatus == NONE) {
315 slotfreespace += size;
316 if (slotoffset == -1)
317 slotoffset = dp->i_offset;
318 if (slotfreespace >= slotneeded) {
319 slotstatus = COMPACT;
320 slotsize = dp->i_offset +
321 ep->d_reclen - slotoffset;
322 }
323 }
324 }
325 }
326
327 /*
328 * Check for a name match.
329 */
330 if (ep->d_ino) {
331 # if (BYTE_ORDER == LITTLE_ENDIAN)
332 if (OFSFMT(vdp))
333 namlen = ep->d_type;
334 else
335 namlen = ep->d_namlen;
336 # else
337 namlen = ep->d_namlen;
338 # endif
339 if (namlen == cnp->cn_namelen &&
340 (cnp->cn_nameptr[0] == ep->d_name[0]) &&
341 !bcmp(cnp->cn_nameptr, ep->d_name,
342 (unsigned)namlen)) {
343 #ifdef UFS_DIRHASH
344 foundentry:
345 #endif
346 /*
347 * Save directory entry's inode number and
348 * reclen in ndp->ni_ufs area, and release
349 * directory buffer.
350 */
351 if (vdp->v_mount->mnt_maxsymlinklen > 0 &&
352 ep->d_type == DT_WHT) {
353 slotstatus = FOUND;
354 slotoffset = dp->i_offset;
355 slotsize = ep->d_reclen;
356 dp->i_reclen = slotsize;
357 enduseful = dp->i_size;
358 ap->a_cnp->cn_flags |= ISWHITEOUT;
359 numdirpasses--;
360 goto notfound;
361 }
362 dp->i_ino = ep->d_ino;
363 dp->i_reclen = ep->d_reclen;
364 goto found;
365 }
366 }
367 prevoff = dp->i_offset;
368 dp->i_offset += ep->d_reclen;
369 entryoffsetinblock += ep->d_reclen;
370 if (ep->d_ino)
371 enduseful = dp->i_offset;
372 }
373 notfound:
374 /*
375 * If we started in the middle of the directory and failed
376 * to find our target, we must check the beginning as well.
377 */
378 if (numdirpasses == 2) {
379 numdirpasses--;
380 dp->i_offset = 0;
381 endsearch = dp->i_diroff;
382 goto searchloop;
383 }
384 if (bp != NULL)
385 brelse(bp);
386 /*
387 * If creating, and at end of pathname and current
388 * directory has not been removed, then can consider
389 * allowing file to be created.
390 */
391 if ((nameiop == CREATE || nameiop == RENAME ||
392 (nameiop == DELETE &&
393 (ap->a_cnp->cn_flags & DOWHITEOUT) &&
394 (ap->a_cnp->cn_flags & ISWHITEOUT))) &&
395 (flags & ISLASTCN) && dp->i_effnlink != 0) {
396 /*
397 * Access for write is interpreted as allowing
398 * creation of files in the directory.
399 */
400 error = VOP_ACCESS(vdp, VWRITE, cred, cnp->cn_proc);
401 if (error)
402 return (error);
403 /*
404 * Return an indication of where the new directory
405 * entry should be put. If we didn't find a slot,
406 * then set dp->i_count to 0 indicating
407 * that the new slot belongs at the end of the
408 * directory. If we found a slot, then the new entry
409 * can be put in the range from dp->i_offset to
410 * dp->i_offset + dp->i_count.
411 */
412 if (slotstatus == NONE) {
413 dp->i_offset = roundup2(dp->i_size, DIRBLKSIZ);
414 dp->i_count = 0;
415 enduseful = dp->i_offset;
416 } else if (nameiop == DELETE) {
417 dp->i_offset = slotoffset;
418 if ((dp->i_offset & (DIRBLKSIZ - 1)) == 0)
419 dp->i_count = 0;
420 else
421 dp->i_count = dp->i_offset - prevoff;
422 } else {
423 dp->i_offset = slotoffset;
424 dp->i_count = slotsize;
425 if (enduseful < slotoffset + slotsize)
426 enduseful = slotoffset + slotsize;
427 }
428 dp->i_endoff = roundup2(enduseful, DIRBLKSIZ);
429 dp->i_flag |= IN_CHANGE | IN_UPDATE;
430 /*
431 * We return with the directory locked, so that
432 * the parameters we set up above will still be
433 * valid if we actually decide to do a direnter().
434 * We return ni_vp == NULL to indicate that the entry
435 * does not currently exist; we leave a pointer to
436 * the (locked) directory inode in ndp->ni_dvp.
437 * The pathname buffer is saved so that the name
438 * can be obtained later.
439 *
440 * NB - if the directory is unlocked, then this
441 * information cannot be used.
442 */
443 cnp->cn_flags |= SAVENAME;
444 if (!lockparent) {
445 VOP_UNLOCK(vdp, 0, p);
446 cnp->cn_flags |= PDIRUNLOCK;
447 }
448 return (EJUSTRETURN);
449 }
450 /*
451 * Insert name into cache (as non-existent) if appropriate.
452 */
453 if ((cnp->cn_flags & MAKEENTRY) && nameiop != CREATE)
454 cache_enter(vdp, *vpp, cnp);
455 return (ENOENT);
456
457 found:
458 if (numdirpasses == 2)
459 nchstats.ncs_pass2++;
460 /*
461 * Check that directory length properly reflects presence
462 * of this entry.
463 */
464 if (dp->i_offset + DIRSIZ(OFSFMT(vdp), ep) > dp->i_size) {
465 ufs_dirbad(dp, dp->i_offset, "i_size too small");
466 dp->i_size = dp->i_offset + DIRSIZ(OFSFMT(vdp), ep);
467 dp->i_flag |= IN_CHANGE | IN_UPDATE;
468 }
469 brelse(bp);
470
471 /*
472 * Found component in pathname.
473 * If the final component of path name, save information
474 * in the cache as to where the entry was found.
475 */
476 if ((flags & ISLASTCN) && nameiop == LOOKUP)
477 dp->i_diroff = dp->i_offset &~ (DIRBLKSIZ - 1);
478
479 /*
480 * If deleting, and at end of pathname, return
481 * parameters which can be used to remove file.
482 * If the wantparent flag isn't set, we return only
483 * the directory (in ndp->ni_dvp), otherwise we go
484 * on and lock the inode, being careful with ".".
485 */
486 if (nameiop == DELETE && (flags & ISLASTCN)) {
487 /*
488 * Write access to directory required to delete files.
489 */
490 error = VOP_ACCESS(vdp, VWRITE, cred, cnp->cn_proc);
491 if (error)
492 return (error);
493 /*
494 * Return pointer to current entry in dp->i_offset,
495 * and distance past previous entry (if there
496 * is a previous entry in this block) in dp->i_count.
497 * Save directory inode pointer in ndp->ni_dvp for dirremove().
498 */
499 if ((dp->i_offset & (DIRBLKSIZ - 1)) == 0)
500 dp->i_count = 0;
501 else
502 dp->i_count = dp->i_offset - prevoff;
503 if (dp->i_number == dp->i_ino) {
504 VREF(vdp);
505 *vpp = vdp;
506 return (0);
507 }
508 if (flags & ISDOTDOT)
509 VOP_UNLOCK(vdp, 0, p); /* race to get the inode */
510 error = VFS_VGET(vdp->v_mount, dp->i_ino, &tdp);
511 if (flags & ISDOTDOT) {
512 if (vn_lock(vdp, LK_EXCLUSIVE | LK_RETRY, p) != 0)
513 cnp->cn_flags |= PDIRUNLOCK;
514 }
515 if (error)
516 return (error);
517 /*
518 * If directory is "sticky", then user must own
519 * the directory, or the file in it, else she
520 * may not delete it (unless she's root). This
521 * implements append-only directories.
522 */
523 if ((dp->i_mode & ISVTX) &&
524 cred->cr_uid != 0 &&
525 cred->cr_uid != dp->i_uid &&
526 VTOI(tdp)->i_uid != cred->cr_uid) {
527 vput(tdp);
528 return (EPERM);
529 }
530 *vpp = tdp;
531 if (!lockparent) {
532 VOP_UNLOCK(vdp, 0, p);
533 cnp->cn_flags |= PDIRUNLOCK;
534 }
535 return (0);
536 }
537
538 /*
539 * If rewriting (RENAME), return the inode and the
540 * information required to rewrite the present directory
541 * Must get inode of directory entry to verify it's a
542 * regular file, or empty directory.
543 */
544 if (nameiop == RENAME && wantparent && (flags & ISLASTCN)) {
545 if ((error = VOP_ACCESS(vdp, VWRITE, cred, cnp->cn_proc)) != 0)
546 return (error);
547 /*
548 * Careful about locking second inode.
549 * This can only occur if the target is ".".
550 */
551 if (dp->i_number == dp->i_ino)
552 return (EISDIR);
553 if (flags & ISDOTDOT)
554 VOP_UNLOCK(vdp, 0, p); /* race to get the inode */
555 error = VFS_VGET(vdp->v_mount, dp->i_ino, &tdp);
556 if (flags & ISDOTDOT) {
557 if (vn_lock(vdp, LK_EXCLUSIVE | LK_RETRY, p) != 0)
558 cnp->cn_flags |= PDIRUNLOCK;
559 }
560 if (error)
561 return (error);
562 *vpp = tdp;
563 cnp->cn_flags |= SAVENAME;
564 if (!lockparent) {
565 VOP_UNLOCK(vdp, 0, p);
566 cnp->cn_flags |= PDIRUNLOCK;
567 }
568 return (0);
569 }
570
571 /*
572 * Step through the translation in the name. We do not `vput' the
573 * directory because we may need it again if a symbolic link
574 * is relative to the current directory. Instead we save it
575 * unlocked as "pdp". We must get the target inode before unlocking
576 * the directory to insure that the inode will not be removed
577 * before we get it. We prevent deadlock by always fetching
578 * inodes from the root, moving down the directory tree. Thus
579 * when following backward pointers ".." we must unlock the
580 * parent directory before getting the requested directory.
581 * There is a potential race condition here if both the current
582 * and parent directories are removed before the VFS_VGET for the
583 * inode associated with ".." returns. We hope that this occurs
584 * infrequently since we cannot avoid this race condition without
585 * implementing a sophisticated deadlock detection algorithm.
586 * Note also that this simple deadlock detection scheme will not
587 * work if the file system has any hard links other than ".."
588 * that point backwards in the directory structure.
589 */
590 pdp = vdp;
591 if (flags & ISDOTDOT) {
592 VOP_UNLOCK(pdp, 0, p); /* race to get the inode */
593 cnp->cn_flags |= PDIRUNLOCK;
594 if ((error = VFS_VGET(vdp->v_mount, dp->i_ino, &tdp)) != 0) {
595 if (vn_lock(pdp, LK_EXCLUSIVE | LK_RETRY, p) == 0)
596 cnp->cn_flags &= ~PDIRUNLOCK;
597 return (error);
598 }
599 if (lockparent && (flags & ISLASTCN)) {
600 if ((error = vn_lock(pdp, LK_EXCLUSIVE, p)) != 0) {
601 vput(tdp);
602 return (error);
603 }
604 cnp->cn_flags &= ~PDIRUNLOCK;
605 }
606 *vpp = tdp;
607 } else if (dp->i_number == dp->i_ino) {
608 VREF(vdp); /* we want ourself, ie "." */
609 *vpp = vdp;
610 } else {
611 error = VFS_VGET(vdp->v_mount, dp->i_ino, &tdp);
612 if (error)
613 return (error);
614 if (!lockparent || !(flags & ISLASTCN)) {
615 VOP_UNLOCK(pdp, 0, p);
616 cnp->cn_flags |= PDIRUNLOCK;
617 }
618 *vpp = tdp;
619 }
620
621 /*
622 * Insert name into cache if appropriate.
623 */
624 if (cnp->cn_flags & MAKEENTRY)
625 cache_enter(vdp, *vpp, cnp);
626 return (0);
627 }
628
629 void
630 ufs_dirbad(ip, offset, how)
631 struct inode *ip;
632 doff_t offset;
633 char *how;
634 {
635 struct mount *mp;
636
637 mp = ITOV(ip)->v_mount;
638 (void)printf("%s: bad dir ino %lu at offset %ld: %s\n",
639 mp->mnt_stat.f_mntonname, (u_long)ip->i_number, (long)offset, how);
640 if ((mp->mnt_flag & MNT_RDONLY) == 0)
641 panic("ufs_dirbad: bad dir");
642 }
643
644 /*
645 * Do consistency checking on a directory entry:
646 * record length must be multiple of 4
647 * entry must fit in rest of its DIRBLKSIZ block
648 * record must be large enough to contain entry
649 * name is not longer than MAXNAMLEN
650 * name must be as long as advertised, and null terminated
651 */
652 int
653 ufs_dirbadentry(dp, ep, entryoffsetinblock)
654 struct vnode *dp;
655 register struct direct *ep;
656 int entryoffsetinblock;
657 {
658 register int i;
659 int namlen;
660
661 # if (BYTE_ORDER == LITTLE_ENDIAN)
662 if (OFSFMT(dp))
663 namlen = ep->d_type;
664 else
665 namlen = ep->d_namlen;
666 # else
667 namlen = ep->d_namlen;
668 # endif
669 if ((ep->d_reclen & 0x3) != 0 ||
670 ep->d_reclen > DIRBLKSIZ - (entryoffsetinblock & (DIRBLKSIZ - 1)) ||
671 ep->d_reclen < DIRSIZ(OFSFMT(dp), ep) || namlen > MAXNAMLEN) {
672 /*return (1); */
673 printf("First bad\n");
674 goto bad;
675 }
676 if (ep->d_ino == 0)
677 return (0);
678 for (i = 0; i < namlen; i++)
679 if (ep->d_name[i] == '\0') {
680 /*return (1); */
681 printf("Second bad\n");
682 goto bad;
683 }
684 if (ep->d_name[i])
685 goto bad;
686 return (0);
687 bad:
688 return (1);
689 }
690
691 /*
692 * Construct a new directory entry after a call to namei, using the
693 * parameters that it left in the componentname argument cnp. The
694 * argument ip is the inode to which the new directory entry will refer.
695 */
696 void
697 ufs_makedirentry(ip, cnp, newdirp)
698 struct inode *ip;
699 struct componentname *cnp;
700 struct direct *newdirp;
701 {
702
703 #ifdef DIAGNOSTIC
704 if ((cnp->cn_flags & SAVENAME) == 0)
705 panic("ufs_makedirentry: missing name");
706 #endif
707 newdirp->d_ino = ip->i_number;
708 newdirp->d_namlen = cnp->cn_namelen;
709 bcopy(cnp->cn_nameptr, newdirp->d_name, (unsigned)cnp->cn_namelen + 1);
710 if (ITOV(ip)->v_mount->mnt_maxsymlinklen > 0)
711 newdirp->d_type = IFTODT(ip->i_mode);
712 else {
713 newdirp->d_type = 0;
714 # if (BYTE_ORDER == LITTLE_ENDIAN)
715 { u_char tmp = newdirp->d_namlen;
716 newdirp->d_namlen = newdirp->d_type;
717 newdirp->d_type = tmp; }
718 # endif
719 }
720 }
721
722 /*
723 * Write a directory entry after a call to namei, using the parameters
724 * that it left in nameidata. The argument dirp is the new directory
725 * entry contents. Dvp is a pointer to the directory to be written,
726 * which was left locked by namei. Remaining parameters (dp->i_offset,
727 * dp->i_count) indicate how the space for the new entry is to be obtained.
728 * Non-null bp indicates that a directory is being created (for the
729 * soft dependency code).
730 */
731 int
732 ufs_direnter(dvp, tvp, dirp, cnp, newdirbp)
733 struct vnode *dvp;
734 struct vnode *tvp;
735 struct direct *dirp;
736 struct componentname *cnp;
737 struct buf *newdirbp;
738 {
739 struct ucred *cr;
740 struct proc *p;
741 int newentrysize;
742 struct inode *dp;
743 struct buf *bp;
744 u_int dsize;
745 struct direct *ep, *nep;
746 int error, ret, blkoff, loc, spacefree, flags;
747 char *dirbuf;
748
749 p = curproc; /* XXX */
750 cr = p->p_ucred;
751
752 dp = VTOI(dvp);
753 newentrysize = DIRSIZ(OFSFMT(dvp), dirp);
754
755 if (dp->i_count == 0) {
756 /*
757 * If dp->i_count is 0, then namei could find no
758 * space in the directory. Here, dp->i_offset will
759 * be on a directory block boundary and we will write the
760 * new entry into a fresh block.
761 */
762 if (dp->i_offset & (DIRBLKSIZ - 1))
763 panic("ufs_direnter: newblk");
764 flags = B_CLRBUF;
765 if (!DOINGSOFTDEP(dvp) && !DOINGASYNC(dvp))
766 flags |= B_SYNC;
767 if ((error = VOP_BALLOC(dvp, (off_t)dp->i_offset, DIRBLKSIZ,
768 cr, flags, &bp)) != 0) {
769 if (DOINGSOFTDEP(dvp) && newdirbp != NULL)
770 bdwrite(newdirbp);
771 return (error);
772 }
773 dp->i_size = dp->i_offset + DIRBLKSIZ;
774 dp->i_flag |= IN_CHANGE | IN_UPDATE;
775 vnode_pager_setsize(dvp, (u_long)dp->i_size);
776 dirp->d_reclen = DIRBLKSIZ;
777 blkoff = dp->i_offset &
778 (VFSTOUFS(dvp->v_mount)->um_mountp->mnt_stat.f_iosize - 1);
779 bcopy((caddr_t)dirp, (caddr_t)bp->b_data + blkoff,newentrysize);
780 #ifdef UFS_DIRHASH
781 if (dp->i_dirhash != NULL) {
782 ufsdirhash_newblk(dp, dp->i_offset);
783 ufsdirhash_add(dp, dirp, dp->i_offset);
784 ufsdirhash_checkblock(dp, (char *)bp->b_data + blkoff,
785 dp->i_offset);
786 }
787 #endif
788 if (DOINGSOFTDEP(dvp)) {
789 /*
790 * Ensure that the entire newly allocated block is a
791 * valid directory so that future growth within the
792 * block does not have to ensure that the block is
793 * written before the inode.
794 */
795 blkoff += DIRBLKSIZ;
796 while (blkoff < bp->b_bcount) {
797 ((struct direct *)
798 (bp->b_data + blkoff))->d_reclen = DIRBLKSIZ;
799 blkoff += DIRBLKSIZ;
800 }
801 softdep_setup_directory_add(bp, dp, dp->i_offset,
802 dirp->d_ino, newdirbp);
803 bdwrite(bp);
804 return (UFS_UPDATE(dvp, 0));
805 }
806 if (DOINGASYNC(dvp)) {
807 bdwrite(bp);
808 return (UFS_UPDATE(dvp, 0));
809 }
810 error = VOP_BWRITE(bp->b_vp, bp);
811 ret = UFS_UPDATE(dvp, 1);
812 if (error == 0)
813 return (ret);
814 return (error);
815 }
816
817 /*
818 * If dp->i_count is non-zero, then namei found space for the new
819 * entry in the range dp->i_offset to dp->i_offset + dp->i_count
820 * in the directory. To use this space, we may have to compact
821 * the entries located there, by copying them together towards the
822 * beginning of the block, leaving the free space in one usable
823 * chunk at the end.
824 */
825
826 /*
827 * Increase size of directory if entry eats into new space.
828 * This should never push the size past a new multiple of
829 * DIRBLKSIZE.
830 *
831 * N.B. - THIS IS AN ARTIFACT OF 4.2 AND SHOULD NEVER HAPPEN.
832 */
833 if (dp->i_offset + dp->i_count > dp->i_size)
834 dp->i_size = dp->i_offset + dp->i_count;
835 /*
836 * Get the block containing the space for the new directory entry.
837 */
838 error = UFS_BLKATOFF(dvp, (off_t)dp->i_offset, &dirbuf, &bp);
839 if (error) {
840 if (DOINGSOFTDEP(dvp) && newdirbp != NULL)
841 bdwrite(newdirbp);
842 return (error);
843 }
844 /*
845 * Find space for the new entry. In the simple case, the entry at
846 * offset base will have the space. If it does not, then namei
847 * arranged that compacting the region dp->i_offset to
848 * dp->i_offset + dp->i_count would yield the space.
849 */
850 ep = (struct direct *)dirbuf;
851 dsize = ep->d_ino ? DIRSIZ(OFSFMT(dvp), ep) : 0;
852 spacefree = ep->d_reclen - dsize;
853 for (loc = ep->d_reclen; loc < dp->i_count; ) {
854 nep = (struct direct *)(dirbuf + loc);
855
856 /* Trim the existing slot (NB: dsize may be zero). */
857 ep->d_reclen = dsize;
858 ep = (struct direct *)((char *)ep + dsize);
859
860 /* Read nep->d_reclen now as the bcopy() may clobber it. */
861 loc += nep->d_reclen;
862 if (nep->d_ino == 0) {
863 /*
864 * A mid-block unused entry. Such entries are
865 * never created by the kernel, but fsck_ffs
866 * can create them (and it doesn't fix them).
867 *
868 * Add up the free space, and initialise the
869 * relocated entry since we don't bcopy it.
870 */
871 spacefree += nep->d_reclen;
872 ep->d_ino = 0;
873 dsize = 0;
874 continue;
875 }
876 dsize = DIRSIZ(OFSFMT(dvp), nep);
877 spacefree += nep->d_reclen - dsize;
878 #ifdef UFS_DIRHASH
879 if (dp->i_dirhash != NULL)
880 ufsdirhash_move(dp, nep,
881 dp->i_offset + ((char *)nep - dirbuf),
882 dp->i_offset + ((char *)ep - dirbuf));
883 #endif
884 if (DOINGSOFTDEP(dvp))
885 softdep_change_directoryentry_offset(dp, dirbuf,
886 (caddr_t)nep, (caddr_t)ep, dsize);
887 else
888 bcopy((caddr_t)nep, (caddr_t)ep, dsize);
889 }
890 /*
891 * Here, `ep' points to a directory entry containing `dsize' in-use
892 * bytes followed by `spacefree' unused bytes. If ep->d_ino == 0,
893 * then the entry is completely unused (dsize == 0). The value
894 * of ep->d_reclen is always indeterminate.
895 *
896 * Update the pointer fields in the previous entry (if any),
897 * copy in the new entry, and write out the block.
898 */
899 if (ep->d_ino == 0 ||
900 (ep->d_ino == WINO &&
901 bcmp(ep->d_name, dirp->d_name, dirp->d_namlen) == 0)) {
902 if (spacefree + dsize < newentrysize)
903 panic("ufs_direnter: compact1");
904 dirp->d_reclen = spacefree + dsize;
905 } else {
906 if (spacefree < newentrysize)
907 panic("ufs_direnter: compact2");
908 dirp->d_reclen = spacefree;
909 ep->d_reclen = dsize;
910 ep = (struct direct *)((char *)ep + dsize);
911 }
912 #ifdef UFS_DIRHASH
913 if (dp->i_dirhash != NULL && (ep->d_ino == 0 ||
914 dirp->d_reclen == spacefree))
915 ufsdirhash_add(dp, dirp, dp->i_offset + ((char *)ep - dirbuf));
916 #endif
917 bcopy((caddr_t)dirp, (caddr_t)ep, (u_int)newentrysize);
918 #ifdef UFS_DIRHASH
919 if (dp->i_dirhash != NULL)
920 ufsdirhash_checkblock(dp, dirbuf -
921 (dp->i_offset & (DIRBLKSIZ - 1)),
922 dp->i_offset & ~(DIRBLKSIZ - 1));
923 #endif
924
925 if (DOINGSOFTDEP(dvp)) {
926 softdep_setup_directory_add(bp, dp,
927 dp->i_offset + (caddr_t)ep - dirbuf, dirp->d_ino, newdirbp);
928 bdwrite(bp);
929 } else {
930 if (DOINGASYNC(dvp)) {
931 bdwrite(bp);
932 error = 0;
933 } else {
934 error = bowrite(bp);
935 }
936 }
937 dp->i_flag |= IN_CHANGE | IN_UPDATE;
938 /*
939 * If all went well, and the directory can be shortened, proceed
940 * with the truncation. Note that we have to unlock the inode for
941 * the entry that we just entered, as the truncation may need to
942 * lock other inodes which can lead to deadlock if we also hold a
943 * lock on the newly entered node.
944 */
945 if (error == 0 && dp->i_endoff && dp->i_endoff < dp->i_size) {
946 if (tvp != NULL)
947 VOP_UNLOCK(tvp, 0, p);
948 #ifdef UFS_DIRHASH
949 if (dp->i_dirhash != NULL)
950 ufsdirhash_dirtrunc(dp, dp->i_endoff);
951 #endif
952 (void) UFS_TRUNCATE(dvp, (off_t)dp->i_endoff, IO_SYNC, cr, p);
953 if (tvp != NULL)
954 vn_lock(tvp, LK_EXCLUSIVE | LK_RETRY, p);
955 }
956 return (error);
957 }
958
959 /*
960 * Remove a directory entry after a call to namei, using
961 * the parameters which it left in nameidata. The entry
962 * dp->i_offset contains the offset into the directory of the
963 * entry to be eliminated. The dp->i_count field contains the
964 * size of the previous record in the directory. If this
965 * is 0, the first entry is being deleted, so we need only
966 * zero the inode number to mark the entry as free. If the
967 * entry is not the first in the directory, we must reclaim
968 * the space of the now empty record by adding the record size
969 * to the size of the previous entry.
970 */
971 int
972 ufs_dirremove(dvp, ip, flags, isrmdir)
973 struct vnode *dvp;
974 struct inode *ip;
975 int flags;
976 int isrmdir;
977 {
978 struct inode *dp;
979 struct direct *ep;
980 struct buf *bp;
981 int error;
982
983 dp = VTOI(dvp);
984
985 if (flags & DOWHITEOUT) {
986 /*
987 * Whiteout entry: set d_ino to WINO.
988 */
989 if ((error =
990 UFS_BLKATOFF(dvp, (off_t)dp->i_offset, (char **)&ep, &bp)) != 0)
991 return (error);
992 ep->d_ino = WINO;
993 ep->d_type = DT_WHT;
994 goto out;
995 }
996
997 if ((error = UFS_BLKATOFF(dvp,
998 (off_t)(dp->i_offset - dp->i_count), (char **)&ep, &bp)) != 0)
999 return (error);
1000 #ifdef UFS_DIRHASH
1001 /*
1002 * Remove the dirhash entry. This is complicated by the fact
1003 * that `ep' is the previous entry when dp->i_count != 0.
1004 */
1005 if (dp->i_dirhash != NULL)
1006 ufsdirhash_remove(dp, (dp->i_count == 0) ? ep :
1007 (struct direct *)((char *)ep + ep->d_reclen), dp->i_offset);
1008 #endif
1009 if (dp->i_count == 0) {
1010 /*
1011 * First entry in block: set d_ino to zero.
1012 */
1013 ep->d_ino = 0;
1014 } else {
1015 /*
1016 * Collapse new free space into previous entry.
1017 */
1018 ep->d_reclen += dp->i_reclen;
1019 }
1020 #ifdef UFS_DIRHASH
1021 if (dp->i_dirhash != NULL)
1022 ufsdirhash_checkblock(dp, (char *)ep -
1023 ((dp->i_offset - dp->i_count) & (DIRBLKSIZ - 1)),
1024 dp->i_offset & ~(DIRBLKSIZ - 1));
1025 #endif
1026 out:
1027 if (DOINGSOFTDEP(dvp)) {
1028 if (ip) {
1029 ip->i_effnlink--;
1030 softdep_change_linkcnt(ip);
1031 softdep_setup_remove(bp, dp, ip, isrmdir);
1032 }
1033 if (softdep_slowdown(dvp)) {
1034 error = VOP_BWRITE(bp->b_vp, bp);
1035 } else {
1036 bdwrite(bp);
1037 error = 0;
1038 }
1039 } else {
1040 if (ip) {
1041 ip->i_effnlink--;
1042 ip->i_nlink--;
1043 ip->i_flag |= IN_CHANGE;
1044 }
1045 if (flags & DOWHITEOUT)
1046 error = VOP_BWRITE(bp->b_vp, bp);
1047 else if (DOINGASYNC(dvp) && dp->i_count != 0) {
1048 bdwrite(bp);
1049 error = 0;
1050 } else
1051 error = bowrite(bp);
1052 }
1053 dp->i_flag |= IN_CHANGE | IN_UPDATE;
1054 return (error);
1055 }
1056
1057 /*
1058 * Rewrite an existing directory entry to point at the inode
1059 * supplied. The parameters describing the directory entry are
1060 * set up by a call to namei.
1061 */
1062 int
1063 ufs_dirrewrite(dp, oip, newinum, newtype, isrmdir)
1064 struct inode *dp, *oip;
1065 ino_t newinum;
1066 int newtype;
1067 int isrmdir;
1068 {
1069 struct buf *bp;
1070 struct direct *ep;
1071 struct vnode *vdp = ITOV(dp);
1072 int error;
1073
1074 error = UFS_BLKATOFF(vdp, (off_t)dp->i_offset, (char **)&ep, &bp);
1075 if (error)
1076 return (error);
1077 ep->d_ino = newinum;
1078 if (!OFSFMT(vdp))
1079 ep->d_type = newtype;
1080 oip->i_effnlink--;
1081 if (DOINGSOFTDEP(vdp)) {
1082 softdep_change_linkcnt(oip);
1083 softdep_setup_directory_change(bp, dp, oip, newinum, isrmdir);
1084 bdwrite(bp);
1085 } else {
1086 oip->i_nlink--;
1087 oip->i_flag |= IN_CHANGE;
1088 if (DOINGASYNC(vdp)) {
1089 bdwrite(bp);
1090 error = 0;
1091 } else {
1092 error = bowrite(bp);
1093 }
1094 }
1095 dp->i_flag |= IN_CHANGE | IN_UPDATE;
1096 return (error);
1097 }
1098
1099 /*
1100 * Check if a directory is empty or not.
1101 * Inode supplied must be locked.
1102 *
1103 * Using a struct dirtemplate here is not precisely
1104 * what we want, but better than using a struct direct.
1105 *
1106 * NB: does not handle corrupted directories.
1107 */
1108 int
1109 ufs_dirempty(ip, parentino, cred)
1110 register struct inode *ip;
1111 ino_t parentino;
1112 struct ucred *cred;
1113 {
1114 register off_t off;
1115 struct dirtemplate dbuf;
1116 register struct direct *dp = (struct direct *)&dbuf;
1117 int error, count, namlen;
1118 #define MINDIRSIZ (sizeof (struct dirtemplate) / 2)
1119
1120 for (off = 0; off < ip->i_size; off += dp->d_reclen) {
1121 error = vn_rdwr(UIO_READ, ITOV(ip), (caddr_t)dp, MINDIRSIZ, off,
1122 UIO_SYSSPACE, IO_NODELOCKED, cred, &count, (struct proc *)0);
1123 /*
1124 * Since we read MINDIRSIZ, residual must
1125 * be 0 unless we're at end of file.
1126 */
1127 if (error || count != 0)
1128 return (0);
1129 /* avoid infinite loops */
1130 if (dp->d_reclen == 0)
1131 return (0);
1132 /* skip empty entries */
1133 if (dp->d_ino == 0 || dp->d_ino == WINO)
1134 continue;
1135 /* accept only "." and ".." */
1136 # if (BYTE_ORDER == LITTLE_ENDIAN)
1137 if (OFSFMT(ITOV(ip)))
1138 namlen = dp->d_type;
1139 else
1140 namlen = dp->d_namlen;
1141 # else
1142 namlen = dp->d_namlen;
1143 # endif
1144 if (namlen > 2)
1145 return (0);
1146 if (dp->d_name[0] != '.')
1147 return (0);
1148 /*
1149 * At this point namlen must be 1 or 2.
1150 * 1 implies ".", 2 implies ".." if second
1151 * char is also "."
1152 */
1153 if (namlen == 1 && dp->d_ino == ip->i_number)
1154 continue;
1155 if (dp->d_name[1] == '.' && dp->d_ino == parentino)
1156 continue;
1157 return (0);
1158 }
1159 return (1);
1160 }
1161
1162 /*
1163 * Check if source directory is in the path of the target directory.
1164 * Target is supplied locked, source is unlocked.
1165 * The target is always vput before returning.
1166 */
1167 int
1168 ufs_checkpath(source, target, cred)
1169 struct inode *source, *target;
1170 struct ucred *cred;
1171 {
1172 struct vnode *vp;
1173 int error, rootino, namlen;
1174 struct dirtemplate dirbuf;
1175
1176 vp = ITOV(target);
1177 if (target->i_number == source->i_number) {
1178 error = EEXIST;
1179 goto out;
1180 }
1181 rootino = ROOTINO;
1182 error = 0;
1183 if (target->i_number == rootino)
1184 goto out;
1185
1186 for (;;) {
1187 if (vp->v_type != VDIR) {
1188 error = ENOTDIR;
1189 break;
1190 }
1191 error = vn_rdwr(UIO_READ, vp, (caddr_t)&dirbuf,
1192 sizeof (struct dirtemplate), (off_t)0, UIO_SYSSPACE,
1193 IO_NODELOCKED, cred, (int *)0, (struct proc *)0);
1194 if (error != 0)
1195 break;
1196 # if (BYTE_ORDER == LITTLE_ENDIAN)
1197 if (OFSFMT(vp))
1198 namlen = dirbuf.dotdot_type;
1199 else
1200 namlen = dirbuf.dotdot_namlen;
1201 # else
1202 namlen = dirbuf.dotdot_namlen;
1203 # endif
1204 if (namlen != 2 ||
1205 dirbuf.dotdot_name[0] != '.' ||
1206 dirbuf.dotdot_name[1] != '.') {
1207 error = ENOTDIR;
1208 break;
1209 }
1210 if (dirbuf.dotdot_ino == source->i_number) {
1211 error = EINVAL;
1212 break;
1213 }
1214 if (dirbuf.dotdot_ino == rootino)
1215 break;
1216 vput(vp);
1217 error = VFS_VGET(vp->v_mount, dirbuf.dotdot_ino, &vp);
1218 if (error) {
1219 vp = NULL;
1220 break;
1221 }
1222 }
1223
1224 out:
1225 if (error == ENOTDIR)
1226 printf("checkpath: .. not a directory\n");
1227 if (vp != NULL)
1228 vput(vp);
1229 return (error);
1230 }
Cache object: 73b8c17c079abd0ff3116266e6ab1bb8
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