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. Neither the name of the University nor the names of its contributors
19 * may be used to endorse or promote products derived from this software
20 * without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 *
34 * @(#)ufs_lookup.c 8.15 (Berkeley) 6/16/95
35 * $FreeBSD: src/sys/ufs/ufs/ufs_lookup.c,v 1.33.2.7 2001/09/22 19:22:13 iedowse Exp $
36 */
37
38 #include "opt_ufs.h"
39
40 #include <sys/param.h>
41 #include <sys/systm.h>
42 #include <sys/kernel.h>
43 #include <sys/buf.h>
44 #include <sys/proc.h>
45 #include <sys/namei.h>
46 #include <sys/stat.h>
47 #include <sys/mount.h>
48 #include <sys/vnode.h>
49 #include <sys/sysctl.h>
50
51 #include <vm/vm.h>
52 #include <vm/vm_extern.h>
53
54 #include "quota.h"
55 #include "inode.h"
56 #include "dir.h"
57 #ifdef UFS_DIRHASH
58 #include "dirhash.h"
59 #endif
60 #include "ufsmount.h"
61 #include "ufs_extern.h"
62 #include "ffs_extern.h"
63
64 #ifdef DIAGNOSTIC
65 int dirchk = 1;
66 #else
67 int dirchk = 0;
68 #endif
69
70 SYSCTL_INT(_debug, OID_AUTO, dircheck, CTLFLAG_RW, &dirchk, 0,
71 "Enable full validation checks of directory");
72
73 /* true if old FS format...*/
74 #define OFSFMT(vp) ((vp)->v_mount->mnt_maxsymlinklen <= 0)
75
76 /*
77 * Convert a component of a pathname into a pointer to a locked inode.
78 * This is a very central and rather complicated routine.
79 * If the filesystem is not maintained in a strict tree hierarchy,
80 * this can result in a deadlock situation (see comments in code below).
81 *
82 * The cnp->cn_nameiop argument is LOOKUP, CREATE, RENAME, or DELETE depending
83 * on whether the name is to be looked up, created, renamed, or deleted.
84 * When CREATE, RENAME, or DELETE is specified, information usable in
85 * creating, renaming, or deleting a directory entry may be calculated.
86 * If flag has LOCKPARENT or'ed into it and the target of the pathname
87 * exists, lookup returns both the target and its parent directory locked.
88 * When creating or renaming and LOCKPARENT is specified, the target may
89 * not be ".". When deleting and LOCKPARENT is specified, the target may
90 * be "."., but the caller must check to ensure it does an vrele and vput
91 * instead of two vputs.
92 *
93 * Overall outline of ufs_lookup:
94 *
95 * search for name in directory, to found or notfound
96 * notfound:
97 * if creating, return locked directory, leaving info on available slots
98 * else return error
99 * found:
100 * if at end of path and deleting, return information to allow delete
101 * if at end of path and rewriting (RENAME and LOCKPARENT), lock target
102 * inode and return info to allow rewrite
103 * if not at end, add name to cache; if at end and neither creating
104 * nor deleting, add name to cache
105 *
106 * ufs_lookup(struct vnode *a_dvp, struct vnode **a_vpp,
107 * struct componentname *a_cnp)
108 */
109 int
ufs_lookup(struct vop_old_lookup_args * ap)110 ufs_lookup(struct vop_old_lookup_args *ap)
111 {
112 struct vnode *vdp; /* vnode for directory being searched */
113 struct inode *dp; /* inode for directory being searched */
114 struct buf *bp; /* a buffer of directory entries */
115 struct direct *ep; /* the current directory entry */
116 int entryoffsetinblock; /* offset of ep in bp's buffer */
117 enum {NONE, COMPACT, FOUND} slotstatus;
118 doff_t slotoffset; /* offset of area with free space */
119 int slotsize; /* size of area at slotoffset */
120 int slotfreespace; /* amount of space free in slot */
121 int slotneeded; /* size of the entry we're seeking */
122 int numdirpasses; /* strategy for directory search */
123 doff_t endsearch; /* offset to end directory search */
124 doff_t prevoff; /* prev entry dp->i_offset */
125 struct vnode *pdp; /* saved dp during symlink work */
126 struct vnode *tdp; /* returned by VFS_VGET */
127 doff_t enduseful; /* pointer past last used dir slot */
128 u_long bmask; /* block offset mask */
129 int lockparent; /* 1 => lockparent flag is set */
130 int wantparent; /* 1 => wantparent or lockparent flag */
131 int namlen, error;
132 struct vnode **vpp = ap->a_vpp;
133 struct componentname *cnp = ap->a_cnp;
134 struct ucred *cred = cnp->cn_cred;
135 int flags = cnp->cn_flags;
136 int nameiop = cnp->cn_nameiop;
137
138 bp = NULL;
139 slotoffset = -1;
140 cnp->cn_flags &= ~CNP_PDIRUNLOCK;
141 /*
142 * XXX there was a soft-update diff about this I couldn't merge.
143 * I think this was the equiv.
144 */
145 *vpp = NULL;
146
147 vdp = ap->a_dvp;
148 dp = VTOI(vdp);
149 lockparent = flags & CNP_LOCKPARENT;
150 wantparent = flags & (CNP_LOCKPARENT|CNP_WANTPARENT);
151
152 /*
153 * We now have a segment name to search for, and a directory to search.
154 *
155 * Suppress search for slots unless creating
156 * file and at end of pathname, in which case
157 * we watch for a place to put the new file in
158 * case it doesn't already exist.
159 */
160 slotstatus = FOUND;
161 slotfreespace = slotsize = slotneeded = 0;
162 if (nameiop == NAMEI_CREATE || nameiop == NAMEI_RENAME) {
163 slotstatus = NONE;
164 slotneeded = DIRECTSIZ(cnp->cn_namelen);
165 }
166 bmask = VFSTOUFS(vdp->v_mount)->um_mountp->mnt_stat.f_iosize - 1;
167
168 #ifdef UFS_DIRHASH
169 /*
170 * Use dirhash for fast operations on large directories. The logic
171 * to determine whether to hash the directory is contained within
172 * ufsdirhash_build(); a zero return means that it decided to hash
173 * this directory and it successfully built up the hash table.
174 */
175 if (ufsdirhash_build(dp) == 0) {
176 /* Look for a free slot if needed. */
177 enduseful = dp->i_size;
178 if (slotstatus != FOUND) {
179 slotoffset = ufsdirhash_findfree(dp, slotneeded,
180 &slotsize);
181 if (slotoffset >= 0) {
182 slotstatus = COMPACT;
183 enduseful = ufsdirhash_enduseful(dp);
184 if (enduseful < 0)
185 enduseful = dp->i_size;
186 }
187 }
188 /* Look up the component. */
189 numdirpasses = 1;
190 entryoffsetinblock = 0; /* silence compiler warning */
191 switch (ufsdirhash_lookup(dp, cnp->cn_nameptr, cnp->cn_namelen,
192 &dp->i_offset, &bp, nameiop == NAMEI_DELETE ? &prevoff : NULL)) {
193 case 0:
194 ep = (struct direct *)((char *)bp->b_data +
195 (dp->i_offset & bmask));
196 goto foundentry;
197 case ENOENT:
198 dp->i_offset = roundup2(dp->i_size, DIRBLKSIZ);
199 goto notfound;
200 default:
201 /* Something failed; just do a linear search. */
202 break;
203 }
204 }
205 #endif /* UFS_DIRHASH */
206 /*
207 * If there is cached information on a previous search of
208 * this directory, pick up where we last left off.
209 * We cache only lookups as these are the most common
210 * and have the greatest payoff. Caching CREATE has little
211 * benefit as it usually must search the entire directory
212 * to determine that the entry does not exist. Caching the
213 * location of the last DELETE or RENAME has not reduced
214 * profiling time and hence has been removed in the interest
215 * of simplicity.
216 */
217 if (nameiop != NAMEI_LOOKUP || dp->i_diroff == 0 ||
218 dp->i_diroff >= dp->i_size) {
219 entryoffsetinblock = 0;
220 dp->i_offset = 0;
221 numdirpasses = 1;
222 } else {
223 dp->i_offset = dp->i_diroff;
224 if ((entryoffsetinblock = dp->i_offset & bmask) &&
225 (error = ffs_blkatoff(vdp, (off_t)dp->i_offset, NULL, &bp)))
226 return (error);
227 numdirpasses = 2;
228 }
229 prevoff = dp->i_offset;
230 endsearch = roundup2(dp->i_size, DIRBLKSIZ);
231 enduseful = 0;
232
233 searchloop:
234 while (dp->i_offset < endsearch) {
235 /*
236 * If necessary, get the next directory block.
237 */
238 if ((dp->i_offset & bmask) == 0) {
239 if (bp != NULL)
240 brelse(bp);
241 error =
242 ffs_blkatoff(vdp, (off_t)dp->i_offset, NULL, &bp);
243 if (error)
244 return (error);
245 entryoffsetinblock = 0;
246 }
247 /*
248 * If still looking for a slot, and at a DIRBLKSIZE
249 * boundary, have to start looking for free space again.
250 */
251 if (slotstatus == NONE &&
252 (entryoffsetinblock & (DIRBLKSIZ - 1)) == 0) {
253 slotoffset = -1;
254 slotfreespace = 0;
255 }
256 /*
257 * Get pointer to next entry.
258 * Full validation checks are slow, so we only check
259 * enough to insure forward progress through the
260 * directory. Complete checks can be run by patching
261 * "dirchk" to be true.
262 */
263 ep = (struct direct *)((char *)bp->b_data + entryoffsetinblock);
264 if (ep->d_reclen == 0 || ep->d_reclen >
265 DIRBLKSIZ - (entryoffsetinblock & (DIRBLKSIZ - 1)) ||
266 (dirchk && ufs_dirbadentry(vdp, ep, entryoffsetinblock))) {
267 int i;
268
269 ufs_dirbad(dp, dp->i_offset, "mangled entry");
270 i = DIRBLKSIZ - (entryoffsetinblock & (DIRBLKSIZ - 1));
271 dp->i_offset += i;
272 entryoffsetinblock += i;
273 continue;
274 }
275
276 /*
277 * If an appropriate sized slot has not yet been found,
278 * check to see if one is available. Also accumulate space
279 * in the current block so that we can determine if
280 * compaction is viable.
281 */
282 if (slotstatus != FOUND) {
283 int size = ep->d_reclen;
284
285 if (ep->d_ino != 0)
286 size -= DIRSIZ(OFSFMT(vdp), ep);
287 if (size > 0) {
288 if (size >= slotneeded) {
289 slotstatus = FOUND;
290 slotoffset = dp->i_offset;
291 slotsize = ep->d_reclen;
292 } else if (slotstatus == NONE) {
293 slotfreespace += size;
294 if (slotoffset == -1)
295 slotoffset = dp->i_offset;
296 if (slotfreespace >= slotneeded) {
297 slotstatus = COMPACT;
298 slotsize = dp->i_offset +
299 ep->d_reclen - slotoffset;
300 }
301 }
302 }
303 }
304
305 /*
306 * Check for a name match.
307 */
308 if (ep->d_ino) {
309 # if (BYTE_ORDER == LITTLE_ENDIAN)
310 if (OFSFMT(vdp))
311 namlen = ep->d_type;
312 else
313 namlen = ep->d_namlen;
314 # else
315 namlen = ep->d_namlen;
316 # endif
317 if (namlen == cnp->cn_namelen &&
318 (cnp->cn_nameptr[0] == ep->d_name[0]) &&
319 !bcmp(cnp->cn_nameptr, ep->d_name,
320 (unsigned)namlen)) {
321 #ifdef UFS_DIRHASH
322 foundentry:
323 #endif
324 /*
325 * Save directory entry's inode number and
326 * reclen in ndp->ni_ufs area, and release
327 * directory buffer.
328 */
329 if (vdp->v_mount->mnt_maxsymlinklen > 0 &&
330 ep->d_type == DT_WHT) {
331 slotstatus = FOUND;
332 slotoffset = dp->i_offset;
333 slotsize = ep->d_reclen;
334 dp->i_reclen = slotsize;
335 enduseful = dp->i_size;
336 ap->a_cnp->cn_flags |= CNP_ISWHITEOUT;
337 numdirpasses--;
338 goto notfound;
339 }
340 dp->i_ino = ep->d_ino;
341 dp->i_reclen = ep->d_reclen;
342 goto found;
343 }
344 }
345 prevoff = dp->i_offset;
346 dp->i_offset += ep->d_reclen;
347 entryoffsetinblock += ep->d_reclen;
348 if (ep->d_ino)
349 enduseful = dp->i_offset;
350 }
351 notfound:
352 /*
353 * If we started in the middle of the directory and failed
354 * to find our target, we must check the beginning as well.
355 */
356 if (numdirpasses == 2) {
357 numdirpasses--;
358 dp->i_offset = 0;
359 endsearch = dp->i_diroff;
360 goto searchloop;
361 }
362 if (bp != NULL)
363 brelse(bp);
364 /*
365 * If creating, and at end of pathname and current
366 * directory has not been removed, then can consider
367 * allowing file to be created.
368 */
369 if ((nameiop == NAMEI_CREATE || nameiop == NAMEI_RENAME ||
370 (nameiop == NAMEI_DELETE &&
371 (ap->a_cnp->cn_flags & CNP_DOWHITEOUT) &&
372 (ap->a_cnp->cn_flags & CNP_ISWHITEOUT))) &&
373 dp->i_effnlink != 0) {
374 /*
375 * Access for write is interpreted as allowing
376 * creation of files in the directory.
377 */
378 error = VOP_EACCESS(vdp, VWRITE, cred);
379 if (error)
380 return (error);
381 /*
382 * Return an indication of where the new directory
383 * entry should be put. If we didn't find a slot,
384 * then set dp->i_count to 0 indicating
385 * that the new slot belongs at the end of the
386 * directory. If we found a slot, then the new entry
387 * can be put in the range from dp->i_offset to
388 * dp->i_offset + dp->i_count.
389 */
390 if (slotstatus == NONE) {
391 dp->i_offset = roundup2(dp->i_size, DIRBLKSIZ);
392 dp->i_count = 0;
393 enduseful = dp->i_offset;
394 } else if (nameiop == NAMEI_DELETE) {
395 dp->i_offset = slotoffset;
396 if ((dp->i_offset & (DIRBLKSIZ - 1)) == 0)
397 dp->i_count = 0;
398 else
399 dp->i_count = dp->i_offset - prevoff;
400 } else {
401 dp->i_offset = slotoffset;
402 dp->i_count = slotsize;
403 if (enduseful < slotoffset + slotsize)
404 enduseful = slotoffset + slotsize;
405 }
406 dp->i_endoff = roundup2(enduseful, DIRBLKSIZ);
407 dp->i_flag |= IN_CHANGE | IN_UPDATE;
408 /*
409 * We return with the directory locked, so that
410 * the parameters we set up above will still be
411 * valid if we actually decide to do a direnter().
412 * We return ni_vp == NULL to indicate that the entry
413 * does not currently exist; we leave a pointer to
414 * the (locked) directory inode in ndp->ni_dvp.
415 * The pathname buffer is saved so that the name
416 * can be obtained later.
417 *
418 * NB - if the directory is unlocked, then this
419 * information cannot be used.
420 */
421 if (!lockparent) {
422 vn_unlock(vdp);
423 cnp->cn_flags |= CNP_PDIRUNLOCK;
424 }
425 return (EJUSTRETURN);
426 }
427 return (ENOENT);
428
429 found:
430 /*
431 * Check that directory length properly reflects presence
432 * of this entry.
433 */
434 if (dp->i_offset + DIRSIZ(OFSFMT(vdp), ep) > dp->i_size) {
435 ufs_dirbad(dp, dp->i_offset, "i_size too small");
436 dp->i_size = dp->i_offset + DIRSIZ(OFSFMT(vdp), ep);
437 dp->i_flag |= IN_CHANGE | IN_UPDATE;
438 }
439 brelse(bp);
440
441 /*
442 * Found component in pathname.
443 * If the final component of path name, save information
444 * in the cache as to where the entry was found.
445 */
446 if (nameiop == NAMEI_LOOKUP)
447 dp->i_diroff = rounddown2(dp->i_offset, DIRBLKSIZ);
448
449 /*
450 * If deleting, and at end of pathname, return
451 * parameters which can be used to remove file.
452 * If the wantparent flag isn't set, we return only
453 * the directory (in ndp->ni_dvp), otherwise we go
454 * on and lock the inode, being careful with ".".
455 */
456 if (nameiop == NAMEI_DELETE) {
457 /*
458 * Write access to directory required to delete files.
459 */
460 error = VOP_EACCESS(vdp, VWRITE, cred);
461 if (error)
462 return (error);
463 /*
464 * Return pointer to current entry in dp->i_offset,
465 * and distance past previous entry (if there
466 * is a previous entry in this block) in dp->i_count.
467 * Save directory inode pointer in ndp->ni_dvp for dirremove().
468 */
469 if ((dp->i_offset & (DIRBLKSIZ - 1)) == 0)
470 dp->i_count = 0;
471 else
472 dp->i_count = dp->i_offset - prevoff;
473 if (dp->i_number == dp->i_ino) {
474 vref(vdp);
475 *vpp = vdp;
476 return (0);
477 }
478 if (flags & CNP_ISDOTDOT)
479 vn_unlock(vdp); /* race to get the inode */
480 error = VFS_VGET(vdp->v_mount, NULL, dp->i_ino, &tdp);
481 if (flags & CNP_ISDOTDOT) {
482 if (vn_lock(vdp, LK_EXCLUSIVE | LK_RETRY |
483 LK_FAILRECLAIM) != 0) {
484 cnp->cn_flags |= CNP_PDIRUNLOCK;
485 }
486 }
487 if (error)
488 return (error);
489 /*
490 * If directory is "sticky", then user must own
491 * the directory, or the file in it, else she
492 * may not delete it (unless she's root). This
493 * implements append-only directories.
494 */
495 if ((dp->i_mode & ISVTX) &&
496 cred->cr_uid != 0 &&
497 cred->cr_uid != dp->i_uid &&
498 VTOI(tdp)->i_uid != cred->cr_uid) {
499 vput(tdp);
500 return (EPERM);
501 }
502 *vpp = tdp;
503 if (!lockparent) {
504 vn_unlock(vdp);
505 cnp->cn_flags |= CNP_PDIRUNLOCK;
506 }
507 return (0);
508 }
509
510 /*
511 * If rewriting (RENAME), return the inode and the
512 * information required to rewrite the present directory
513 * Must get inode of directory entry to verify it's a
514 * regular file, or empty directory.
515 */
516 if (nameiop == NAMEI_RENAME && wantparent) {
517 if ((error = VOP_EACCESS(vdp, VWRITE, cred)) != 0)
518 return (error);
519 /*
520 * Careful about locking second inode.
521 * This can only occur if the target is ".".
522 */
523 if (dp->i_number == dp->i_ino)
524 return (EISDIR);
525 if (flags & CNP_ISDOTDOT)
526 vn_unlock(vdp); /* race to get the inode */
527 error = VFS_VGET(vdp->v_mount, NULL, dp->i_ino, &tdp);
528 if (flags & CNP_ISDOTDOT) {
529 if (vn_lock(vdp, LK_EXCLUSIVE | LK_RETRY |
530 LK_FAILRECLAIM) != 0) {
531 cnp->cn_flags |= CNP_PDIRUNLOCK;
532 }
533 }
534 if (error)
535 return (error);
536 *vpp = tdp;
537 if (!lockparent) {
538 vn_unlock(vdp);
539 cnp->cn_flags |= CNP_PDIRUNLOCK;
540 }
541 return (0);
542 }
543
544 /*
545 * Step through the translation in the name. We do not `vput' the
546 * directory because we may need it again if a symbolic link
547 * is relative to the current directory. Instead we save it
548 * unlocked as "pdp". We must get the target inode before unlocking
549 * the directory to insure that the inode will not be removed
550 * before we get it. We prevent deadlock by always fetching
551 * inodes from the root, moving down the directory tree. Thus
552 * when following backward pointers ".." we must unlock the
553 * parent directory before getting the requested directory.
554 * There is a potential race condition here if both the current
555 * and parent directories are removed before the VFS_VGET for the
556 * inode associated with ".." returns. We hope that this occurs
557 * infrequently since we cannot avoid this race condition without
558 * implementing a sophisticated deadlock detection algorithm.
559 * Note also that this simple deadlock detection scheme will not
560 * work if the filesystem has any hard links other than ".."
561 * that point backwards in the directory structure.
562 */
563 pdp = vdp;
564 if (flags & CNP_ISDOTDOT) {
565 vn_unlock(pdp); /* race to get the inode */
566 cnp->cn_flags |= CNP_PDIRUNLOCK;
567 error = VFS_VGET(vdp->v_mount, NULL, dp->i_ino, &tdp);
568 if (error) {
569 if (vn_lock(pdp, LK_EXCLUSIVE | LK_RETRY |
570 LK_FAILRECLAIM) == 0) {
571 cnp->cn_flags &= ~CNP_PDIRUNLOCK;
572 }
573 return (error);
574 }
575 if (lockparent) {
576 error = vn_lock(pdp, LK_EXCLUSIVE | LK_FAILRECLAIM);
577 if (error) {
578 vput(tdp);
579 return (error);
580 }
581 cnp->cn_flags &= ~CNP_PDIRUNLOCK;
582 }
583 *vpp = tdp;
584 } else if (dp->i_number == dp->i_ino) {
585 vref(vdp); /* we want ourself, ie "." */
586 *vpp = vdp;
587 } else {
588 error = VFS_VGET(vdp->v_mount, NULL, dp->i_ino, &tdp);
589 if (error)
590 return (error);
591 if (!lockparent) {
592 vn_unlock(pdp);
593 cnp->cn_flags |= CNP_PDIRUNLOCK;
594 }
595 *vpp = tdp;
596 }
597 return (0);
598 }
599
600 void
ufs_dirbad(struct inode * ip,doff_t offset,char * how)601 ufs_dirbad(struct inode *ip, doff_t offset, char *how)
602 {
603 struct mount *mp;
604
605 mp = ITOV(ip)->v_mount;
606 (void)kprintf("%s: bad dir ino %lu at offset %ld: %s\n",
607 mp->mnt_stat.f_mntfromname, (u_long)ip->i_number, (long)offset, how);
608 if ((mp->mnt_flag & MNT_RDONLY) == 0)
609 panic("ufs_dirbad: bad dir");
610 }
611
612 /*
613 * Do consistency checking on a directory entry:
614 * record length must be multiple of 4
615 * entry must fit in rest of its DIRBLKSIZ block
616 * record must be large enough to contain entry
617 * name is not longer than MAXNAMLEN
618 * name must be as long as advertised, and null terminated
619 */
620 int
ufs_dirbadentry(struct vnode * dp,struct direct * ep,int entryoffsetinblock)621 ufs_dirbadentry(struct vnode *dp, struct direct *ep, int entryoffsetinblock)
622 {
623 int i;
624 int namlen;
625
626 # if (BYTE_ORDER == LITTLE_ENDIAN)
627 if (OFSFMT(dp))
628 namlen = ep->d_type;
629 else
630 namlen = ep->d_namlen;
631 # else
632 namlen = ep->d_namlen;
633 # endif
634 if ((ep->d_reclen & 0x3) != 0 ||
635 ep->d_reclen > DIRBLKSIZ - (entryoffsetinblock & (DIRBLKSIZ - 1)) ||
636 ep->d_reclen < DIRSIZ(OFSFMT(dp), ep) || namlen > MAXNAMLEN) {
637 /*return (1); */
638 kprintf("First bad\n");
639 goto bad;
640 }
641 if (ep->d_ino == 0)
642 return (0);
643 for (i = 0; i < namlen; i++)
644 if (ep->d_name[i] == '\0') {
645 /*return (1); */
646 kprintf("Second bad\n");
647 goto bad;
648 }
649 if (ep->d_name[i])
650 goto bad;
651 return (0);
652 bad:
653 return (1);
654 }
655
656 /*
657 * Construct a new directory entry after a call to namei, using the
658 * parameters that it left in the componentname argument cnp. The
659 * argument ip is the inode to which the new directory entry will refer.
660 */
661 void
ufs_makedirentry(struct inode * ip,struct componentname * cnp,struct direct * newdirp)662 ufs_makedirentry(struct inode *ip, struct componentname *cnp,
663 struct direct *newdirp)
664 {
665
666 newdirp->d_ino = ip->i_number;
667 newdirp->d_namlen = cnp->cn_namelen;
668 bcopy(cnp->cn_nameptr, newdirp->d_name, (unsigned)cnp->cn_namelen + 1);
669 if (ITOV(ip)->v_mount->mnt_maxsymlinklen > 0)
670 newdirp->d_type = IFTODT(ip->i_mode);
671 else {
672 newdirp->d_type = 0;
673 # if (BYTE_ORDER == LITTLE_ENDIAN)
674 { u_char tmp = newdirp->d_namlen;
675 newdirp->d_namlen = newdirp->d_type;
676 newdirp->d_type = tmp; }
677 # endif
678 }
679 }
680
681 /*
682 * Write a directory entry after a call to namei, using the parameters
683 * that it left in the directory inode. The argument dirp is the new directory
684 * entry contents. Dvp is a pointer to the directory to be written,
685 * which was left locked by namei. Remaining parameters (dp->i_offset,
686 * dp->i_count) indicate how the space for the new entry is to be obtained.
687 * Non-null bp indicates that a directory is being created (for the
688 * soft dependency code).
689 */
690 int
ufs_direnter(struct vnode * dvp,struct vnode * tvp,struct direct * dirp,struct componentname * cnp,struct buf * newdirbp)691 ufs_direnter(struct vnode *dvp, struct vnode *tvp, struct direct *dirp,
692 struct componentname *cnp, struct buf *newdirbp)
693 {
694 struct ucred *cred;
695 int newentrysize;
696 struct inode *dp;
697 struct buf *bp;
698 uint dsize;
699 struct direct *ep, *nep;
700 int error, ret, blkoff, loc, spacefree, flags;
701 char *dirbuf;
702
703 cred = cnp->cn_cred;
704 KKASSERT(cred != NULL);
705
706 dp = VTOI(dvp);
707 newentrysize = DIRSIZ(OFSFMT(dvp), dirp);
708
709 if (dp->i_count == 0) {
710 /*
711 * If dp->i_count is 0, then namei could find no
712 * space in the directory. Here, dp->i_offset will
713 * be on a directory block boundary and we will write the
714 * new entry into a fresh block.
715 */
716 if (dp->i_offset & (DIRBLKSIZ - 1))
717 panic("ufs_direnter: newblk");
718 nvnode_pager_setsize(dvp, dp->i_offset + DIRBLKSIZ,
719 DIRBLKSIZ, -1);
720 flags = B_CLRBUF;
721 if (!DOINGSOFTDEP(dvp) && !DOINGASYNC(dvp))
722 flags |= B_SYNC;
723 if ((error = VOP_BALLOC(dvp, (off_t)dp->i_offset, DIRBLKSIZ,
724 cred, flags, &bp)) != 0) {
725 if (DOINGSOFTDEP(dvp) && newdirbp != NULL)
726 bdwrite(newdirbp);
727 return (error);
728 }
729 dp->i_size = dp->i_offset + DIRBLKSIZ;
730 dp->i_flag |= IN_CHANGE | IN_UPDATE;
731 dirp->d_reclen = DIRBLKSIZ;
732 blkoff = dp->i_offset &
733 (VFSTOUFS(dvp->v_mount)->um_mountp->mnt_stat.f_iosize - 1);
734 bcopy((caddr_t)dirp, (caddr_t)bp->b_data + blkoff,newentrysize);
735 #ifdef UFS_DIRHASH
736 if (dp->i_dirhash != NULL) {
737 ufsdirhash_newblk(dp, dp->i_offset);
738 ufsdirhash_add(dp, dirp, dp->i_offset);
739 ufsdirhash_checkblock(dp, (char *)bp->b_data + blkoff,
740 dp->i_offset);
741 }
742 #endif
743 if (DOINGSOFTDEP(dvp)) {
744 /*
745 * Ensure that the entire newly allocated block is a
746 * valid directory so that future growth within the
747 * block does not have to ensure that the block is
748 * written before the inode.
749 */
750 blkoff += DIRBLKSIZ;
751 while (blkoff < bp->b_bcount) {
752 ((struct direct *)
753 (bp->b_data + blkoff))->d_reclen = DIRBLKSIZ;
754 blkoff += DIRBLKSIZ;
755 }
756 softdep_setup_directory_add(bp, dp, dp->i_offset,
757 dirp->d_ino, newdirbp);
758 bdwrite(bp);
759 return (ffs_update(dvp, 0));
760 }
761 if (DOINGASYNC(dvp)) {
762 bdwrite(bp);
763 return (ffs_update(dvp, 0));
764 }
765 error = bwrite(bp);
766 ret = ffs_update(dvp, 1);
767 if (error == 0)
768 return (ret);
769 return (error);
770 }
771
772 /*
773 * If dp->i_count is non-zero, then namei found space for the new
774 * entry in the range dp->i_offset to dp->i_offset + dp->i_count
775 * in the directory. To use this space, we may have to compact
776 * the entries located there, by copying them together towards the
777 * beginning of the block, leaving the free space in one usable
778 * chunk at the end.
779 */
780
781 /*
782 * Increase size of directory if entry eats into new space.
783 * This should never push the size past a new multiple of
784 * DIRBLKSIZE.
785 *
786 * N.B. - THIS IS AN ARTIFACT OF 4.2 AND SHOULD NEVER HAPPEN.
787 */
788 if (dp->i_offset + dp->i_count > dp->i_size)
789 dp->i_size = dp->i_offset + dp->i_count;
790 /*
791 * Get the block containing the space for the new directory entry.
792 */
793 error = ffs_blkatoff(dvp, (off_t)dp->i_offset, &dirbuf, &bp);
794 if (error) {
795 if (DOINGSOFTDEP(dvp) && newdirbp != NULL)
796 bdwrite(newdirbp);
797 return (error);
798 }
799 /*
800 * Find space for the new entry. In the simple case, the entry at
801 * offset base will have the space. If it does not, then namei
802 * arranged that compacting the region dp->i_offset to
803 * dp->i_offset + dp->i_count would yield the space.
804 */
805 ep = (struct direct *)dirbuf;
806 dsize = ep->d_ino ? DIRSIZ(OFSFMT(dvp), ep) : 0;
807 spacefree = ep->d_reclen - dsize;
808 for (loc = ep->d_reclen; loc < dp->i_count; ) {
809 nep = (struct direct *)(dirbuf + loc);
810
811 /* Trim the existing slot (NB: dsize may be zero). */
812 ep->d_reclen = dsize;
813 ep = (struct direct *)((char *)ep + dsize);
814
815 /* Read nep->d_reclen now as the bcopy() may clobber it. */
816 loc += nep->d_reclen;
817 if (nep->d_ino == 0) {
818 /*
819 * A mid-block unused entry. Such entries are
820 * never created by the kernel, but fsck_ffs
821 * can create them (and it doesn't fix them).
822 *
823 * Add up the free space, and initialise the
824 * relocated entry since we don't bcopy it.
825 */
826 spacefree += nep->d_reclen;
827 ep->d_ino = 0;
828 dsize = 0;
829 continue;
830 }
831 dsize = DIRSIZ(OFSFMT(dvp), nep);
832 spacefree += nep->d_reclen - dsize;
833 #ifdef UFS_DIRHASH
834 if (dp->i_dirhash != NULL)
835 ufsdirhash_move(dp, nep,
836 dp->i_offset + ((char *)nep - dirbuf),
837 dp->i_offset + ((char *)ep - dirbuf));
838 #endif
839 if (DOINGSOFTDEP(dvp))
840 softdep_change_directoryentry_offset(dp, dirbuf,
841 (caddr_t)nep, (caddr_t)ep, dsize);
842 else
843 bcopy((caddr_t)nep, (caddr_t)ep, dsize);
844 }
845 /*
846 * Here, `ep' points to a directory entry containing `dsize' in-use
847 * bytes followed by `spacefree' unused bytes. If ep->d_ino == 0,
848 * then the entry is completely unused (dsize == 0). The value
849 * of ep->d_reclen is always indeterminate.
850 *
851 * Update the pointer fields in the previous entry (if any),
852 * copy in the new entry, and write out the block.
853 */
854 if (ep->d_ino == 0 ||
855 (ep->d_ino == UFS_WINO &&
856 bcmp(ep->d_name, dirp->d_name, dirp->d_namlen) == 0)) {
857 if (spacefree + dsize < newentrysize)
858 panic("ufs_direnter: compact1");
859 dirp->d_reclen = spacefree + dsize;
860 } else {
861 if (spacefree < newentrysize)
862 panic("ufs_direnter: compact2");
863 dirp->d_reclen = spacefree;
864 ep->d_reclen = dsize;
865 ep = (struct direct *)((char *)ep + dsize);
866 }
867 #ifdef UFS_DIRHASH
868 if (dp->i_dirhash != NULL && (ep->d_ino == 0 ||
869 dirp->d_reclen == spacefree))
870 ufsdirhash_add(dp, dirp, dp->i_offset + ((char *)ep - dirbuf));
871 #endif
872 bcopy((caddr_t)dirp, (caddr_t)ep, (uint)newentrysize);
873 #ifdef UFS_DIRHASH
874 if (dp->i_dirhash != NULL)
875 ufsdirhash_checkblock(dp, dirbuf -
876 (dp->i_offset & (DIRBLKSIZ - 1)),
877 rounddown2(dp->i_offset, DIRBLKSIZ));
878 #endif
879
880 if (DOINGSOFTDEP(dvp)) {
881 softdep_setup_directory_add(bp, dp,
882 dp->i_offset + (caddr_t)ep - dirbuf, dirp->d_ino, newdirbp);
883 bdwrite(bp);
884 } else {
885 if (DOINGASYNC(dvp)) {
886 bdwrite(bp);
887 error = 0;
888 } else {
889 error = bwrite(bp);
890 }
891 }
892 dp->i_flag |= IN_CHANGE | IN_UPDATE;
893 /*
894 * If all went well, and the directory can be shortened, proceed
895 * with the truncation. Note that we have to unlock the inode for
896 * the entry that we just entered, as the truncation may need to
897 * lock other inodes which can lead to deadlock if we also hold a
898 * lock on the newly entered node.
899 */
900 if (error == 0 && dp->i_endoff && dp->i_endoff < dp->i_size) {
901 if (tvp != NULL)
902 vn_unlock(tvp);
903 #ifdef UFS_DIRHASH
904 if (dp->i_dirhash != NULL)
905 ufsdirhash_dirtrunc(dp, dp->i_endoff);
906 #endif
907 (void)ffs_truncate(dvp, (off_t)dp->i_endoff, IO_SYNC, cred);
908 if (tvp != NULL)
909 vn_lock(tvp, LK_EXCLUSIVE | LK_RETRY);
910 }
911 return (error);
912 }
913
914 /*
915 * Remove a directory entry after a call to namei, using
916 * the parameters which it left in the directory inode. The entry
917 * dp->i_offset contains the offset into the directory of the
918 * entry to be eliminated. The dp->i_count field contains the
919 * size of the previous record in the directory. If this
920 * is 0, the first entry is being deleted, so we need only
921 * zero the inode number to mark the entry as free. If the
922 * entry is not the first in the directory, we must reclaim
923 * the space of the now empty record by adding the record size
924 * to the size of the previous entry.
925 */
926 int
ufs_dirremove(struct vnode * dvp,struct inode * ip,int flags,int isrmdir)927 ufs_dirremove(struct vnode *dvp, struct inode *ip, int flags, int isrmdir)
928 {
929 struct inode *dp;
930 struct direct *ep;
931 struct buf *bp;
932 int error;
933
934 dp = VTOI(dvp);
935
936 if (flags & CNP_DOWHITEOUT) {
937 /*
938 * Whiteout entry: set d_ino to UFS_WINO.
939 */
940 if ((error =
941 ffs_blkatoff(dvp, (off_t)dp->i_offset, (char **)&ep, &bp)) != 0)
942 return (error);
943 ep->d_ino = UFS_WINO;
944 ep->d_type = DT_WHT;
945 goto out;
946 }
947
948 if ((error = ffs_blkatoff(dvp,
949 (off_t)(dp->i_offset - dp->i_count), (char **)&ep, &bp)) != 0)
950 return (error);
951 #ifdef UFS_DIRHASH
952 /*
953 * Remove the dirhash entry. This is complicated by the fact
954 * that `ep' is the previous entry when dp->i_count != 0.
955 */
956 if (dp->i_dirhash != NULL)
957 ufsdirhash_remove(dp, (dp->i_count == 0) ? ep :
958 (struct direct *)((char *)ep + ep->d_reclen), dp->i_offset);
959 #endif
960 if (dp->i_count == 0) {
961 /*
962 * First entry in block: set d_ino to zero.
963 */
964 ep->d_ino = 0;
965 } else {
966 /*
967 * Collapse new free space into previous entry.
968 */
969 ep->d_reclen += dp->i_reclen;
970 }
971 #ifdef UFS_DIRHASH
972 if (dp->i_dirhash != NULL)
973 ufsdirhash_checkblock(dp, (char *)ep -
974 ((dp->i_offset - dp->i_count) & (DIRBLKSIZ - 1)),
975 rounddown2(dp->i_offset, DIRBLKSIZ));
976 #endif
977 out:
978 if (DOINGSOFTDEP(dvp)) {
979 if (ip) {
980 ip->i_effnlink--;
981 softdep_change_linkcnt(ip);
982 softdep_setup_remove(bp, dp, ip, isrmdir);
983 }
984 if (softdep_slowdown(dvp)) {
985 error = bwrite(bp);
986 } else {
987 bdwrite(bp);
988 error = 0;
989 }
990 } else {
991 if (ip) {
992 ip->i_effnlink--;
993 ip->i_nlink--;
994 ip->i_flag |= IN_CHANGE;
995 }
996 if (flags & CNP_DOWHITEOUT)
997 error = bwrite(bp);
998 else if (DOINGASYNC(dvp) && dp->i_count != 0) {
999 bdwrite(bp);
1000 error = 0;
1001 } else {
1002 error = bwrite(bp);
1003 }
1004 }
1005 dp->i_flag |= IN_CHANGE | IN_UPDATE;
1006 return (error);
1007 }
1008
1009 /*
1010 * Rewrite an existing directory entry to point at the inode
1011 * supplied. The parameters describing the directory entry are
1012 * set up by a call to namei.
1013 */
1014 int
ufs_dirrewrite(struct inode * dp,struct inode * oip,ino_t newinum,int newtype,int isrmdir)1015 ufs_dirrewrite(struct inode *dp, struct inode *oip, ino_t newinum, int newtype,
1016 int isrmdir)
1017 {
1018 struct buf *bp;
1019 struct direct *ep;
1020 struct vnode *vdp = ITOV(dp);
1021 int error;
1022
1023 error = ffs_blkatoff(vdp, (off_t)dp->i_offset, (char **)&ep, &bp);
1024 if (error)
1025 return (error);
1026 ep->d_ino = newinum;
1027 if (!OFSFMT(vdp))
1028 ep->d_type = newtype;
1029 oip->i_effnlink--;
1030 if (DOINGSOFTDEP(vdp)) {
1031 softdep_change_linkcnt(oip);
1032 softdep_setup_directory_change(bp, dp, oip, newinum, isrmdir);
1033 bdwrite(bp);
1034 } else {
1035 oip->i_nlink--;
1036 oip->i_flag |= IN_CHANGE;
1037 if (DOINGASYNC(vdp)) {
1038 bdwrite(bp);
1039 error = 0;
1040 } else {
1041 error = bwrite(bp);
1042 }
1043 }
1044 dp->i_flag |= IN_CHANGE | IN_UPDATE;
1045 return (error);
1046 }
1047
1048 /*
1049 * Check if a directory is empty or not.
1050 * Inode supplied must be locked.
1051 *
1052 * Using a struct dirtemplate here is not precisely
1053 * what we want, but better than using a struct direct.
1054 *
1055 * NB: does not handle corrupted directories.
1056 */
1057 int
ufs_dirempty(struct inode * ip,ino_t parentino,struct ucred * cred)1058 ufs_dirempty(struct inode *ip, ino_t parentino, struct ucred *cred)
1059 {
1060 off_t off;
1061 struct dirtemplate dbuf;
1062 struct direct *dp = (struct direct *)&dbuf;
1063 int error, count, namlen;
1064 #define MINDIRSIZ (sizeof (struct dirtemplate) / 2)
1065
1066 for (off = 0; off < ip->i_size; off += dp->d_reclen) {
1067 error = vn_rdwr(UIO_READ, ITOV(ip), (caddr_t)dp, MINDIRSIZ, off,
1068 UIO_SYSSPACE, IO_NODELOCKED, cred, &count);
1069 /*
1070 * Since we read MINDIRSIZ, residual must
1071 * be 0 unless we're at end of file.
1072 */
1073 if (error || count != 0)
1074 return (0);
1075 /* avoid infinite loops */
1076 if (dp->d_reclen == 0)
1077 return (0);
1078 /* skip empty entries */
1079 if (dp->d_ino == 0 || dp->d_ino == UFS_WINO)
1080 continue;
1081 /* accept only "." and ".." */
1082 # if (BYTE_ORDER == LITTLE_ENDIAN)
1083 if (OFSFMT(ITOV(ip)))
1084 namlen = dp->d_type;
1085 else
1086 namlen = dp->d_namlen;
1087 # else
1088 namlen = dp->d_namlen;
1089 # endif
1090 if (namlen > 2)
1091 return (0);
1092 if (dp->d_name[0] != '.')
1093 return (0);
1094 /*
1095 * At this point namlen must be 1 or 2.
1096 * 1 implies ".", 2 implies ".." if second
1097 * char is also "."
1098 */
1099 if (namlen == 1 && dp->d_ino == ip->i_number)
1100 continue;
1101 if (dp->d_name[1] == '.' && dp->d_ino == parentino)
1102 continue;
1103 return (0);
1104 }
1105 return (1);
1106 }
1107
1108 /*
1109 * Check if source directory is in the path of the target directory.
1110 * Target is supplied locked, source is unlocked.
1111 * The target is always vput before returning.
1112 */
1113 int
ufs_checkpath(struct inode * source,struct inode * target,struct ucred * cred)1114 ufs_checkpath(struct inode *source, struct inode *target, struct ucred *cred)
1115 {
1116 struct vnode *vp;
1117 int error, rootino, namlen;
1118 struct dirtemplate dirbuf;
1119
1120 vp = ITOV(target);
1121 if (target->i_number == source->i_number) {
1122 error = EEXIST;
1123 goto out;
1124 }
1125 rootino = UFS_ROOTINO;
1126 error = 0;
1127 if (target->i_number == rootino)
1128 goto out;
1129
1130 for (;;) {
1131 if (vp->v_type != VDIR) {
1132 error = ENOTDIR;
1133 break;
1134 }
1135 error = vn_rdwr(UIO_READ, vp, (caddr_t)&dirbuf,
1136 sizeof (struct dirtemplate), (off_t)0,
1137 UIO_SYSSPACE, IO_NODELOCKED, cred, NULL);
1138 if (error != 0)
1139 break;
1140 # if (BYTE_ORDER == LITTLE_ENDIAN)
1141 if (OFSFMT(vp))
1142 namlen = dirbuf.dotdot_type;
1143 else
1144 namlen = dirbuf.dotdot_namlen;
1145 # else
1146 namlen = dirbuf.dotdot_namlen;
1147 # endif
1148 if (namlen != 2 ||
1149 dirbuf.dotdot_name[0] != '.' ||
1150 dirbuf.dotdot_name[1] != '.') {
1151 error = ENOTDIR;
1152 break;
1153 }
1154 if (dirbuf.dotdot_ino == source->i_number) {
1155 error = EINVAL;
1156 break;
1157 }
1158 if (dirbuf.dotdot_ino == rootino)
1159 break;
1160 vput(vp);
1161 error = VFS_VGET(vp->v_mount, NULL, dirbuf.dotdot_ino, &vp);
1162 if (error) {
1163 vp = NULL;
1164 break;
1165 }
1166 }
1167
1168 out:
1169 if (error == ENOTDIR)
1170 kprintf("checkpath: .. not a directory\n");
1171 if (vp != NULL)
1172 vput(vp);
1173 return (error);
1174 }
1175