1 /*-
2 * modified for Lites 1.1
3 *
4 * Aug 1995, Godmar Back (gback@cs.utah.edu)
5 * University of Utah, Department of Computer Science
6 */
7 /*-
8 * Copyright (c) 1989, 1993
9 * The Regents of the University of California. All rights reserved.
10 * (c) UNIX System Laboratories, Inc.
11 * All or some portions of this file are derived from material licensed
12 * to the University of California by American Telephone and Telegraph
13 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
14 * the permission of UNIX System Laboratories, Inc.
15 *
16 * Redistribution and use in source and binary forms, with or without
17 * modification, are permitted provided that the following conditions
18 * are met:
19 * 1. Redistributions of source code must retain the above copyright
20 * notice, this list of conditions and the following disclaimer.
21 * 2. Redistributions in binary form must reproduce the above copyright
22 * notice, this list of conditions and the following disclaimer in the
23 * documentation and/or other materials provided with the distribution.
24 * 4. Neither the name of the University nor the names of its contributors
25 * may be used to endorse or promote products derived from this software
26 * without specific prior written permission.
27 *
28 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
29 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
30 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
31 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
32 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
33 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
34 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
35 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
36 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
37 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
38 * SUCH DAMAGE.
39 *
40 * @(#)ufs_lookup.c 8.6 (Berkeley) 4/1/94
41 * $FreeBSD$
42 */
43
44 #include <sys/param.h>
45 #include <sys/systm.h>
46 #include <sys/namei.h>
47 #include <sys/bio.h>
48 #include <sys/buf.h>
49 #include <sys/endian.h>
50 #include <sys/mount.h>
51 #include <sys/vnode.h>
52 #include <sys/malloc.h>
53 #include <sys/dirent.h>
54 #include <sys/sysctl.h>
55
56 #include <ufs/ufs/dir.h>
57
58 #include <fs/ext2fs/inode.h>
59 #include <fs/ext2fs/ext2_mount.h>
60 #include <fs/ext2fs/ext2fs.h>
61 #include <fs/ext2fs/ext2_dinode.h>
62 #include <fs/ext2fs/ext2_dir.h>
63 #include <fs/ext2fs/ext2_extern.h>
64
65 #ifdef INVARIANTS
66 static int dirchk = 1;
67 #else
68 static int dirchk = 0;
69 #endif
70
71 static SYSCTL_NODE(_vfs, OID_AUTO, e2fs, CTLFLAG_RD, 0, "EXT2FS filesystem");
72 SYSCTL_INT(_vfs_e2fs, OID_AUTO, dircheck, CTLFLAG_RW, &dirchk, 0, "");
73
74 /*
75 DIRBLKSIZE in ffs is DEV_BSIZE (in most cases 512)
76 while it is the native blocksize in ext2fs - thus, a #define
77 is no longer appropriate
78 */
79 #undef DIRBLKSIZ
80
81 static u_char ext2_ft_to_dt[] = {
82 DT_UNKNOWN, /* EXT2_FT_UNKNOWN */
83 DT_REG, /* EXT2_FT_REG_FILE */
84 DT_DIR, /* EXT2_FT_DIR */
85 DT_CHR, /* EXT2_FT_CHRDEV */
86 DT_BLK, /* EXT2_FT_BLKDEV */
87 DT_FIFO, /* EXT2_FT_FIFO */
88 DT_SOCK, /* EXT2_FT_SOCK */
89 DT_LNK, /* EXT2_FT_SYMLINK */
90 };
91 #define FTTODT(ft) \
92 ((ft) < nitems(ext2_ft_to_dt) ? ext2_ft_to_dt[(ft)] : DT_UNKNOWN)
93
94 static u_char dt_to_ext2_ft[] = {
95 EXT2_FT_UNKNOWN, /* DT_UNKNOWN */
96 EXT2_FT_FIFO, /* DT_FIFO */
97 EXT2_FT_CHRDEV, /* DT_CHR */
98 EXT2_FT_UNKNOWN, /* unused */
99 EXT2_FT_DIR, /* DT_DIR */
100 EXT2_FT_UNKNOWN, /* unused */
101 EXT2_FT_BLKDEV, /* DT_BLK */
102 EXT2_FT_UNKNOWN, /* unused */
103 EXT2_FT_REG_FILE, /* DT_REG */
104 EXT2_FT_UNKNOWN, /* unused */
105 EXT2_FT_SYMLINK, /* DT_LNK */
106 EXT2_FT_UNKNOWN, /* unused */
107 EXT2_FT_SOCK, /* DT_SOCK */
108 EXT2_FT_UNKNOWN, /* unused */
109 EXT2_FT_UNKNOWN, /* DT_WHT */
110 };
111 #define DTTOFT(dt) \
112 ((dt) < nitems(dt_to_ext2_ft) ? dt_to_ext2_ft[(dt)] : EXT2_FT_UNKNOWN)
113
114 static int ext2_dirbadentry(struct vnode *dp, struct ext2fs_direct_2 *de,
115 int entryoffsetinblock);
116 static int ext2_is_dot_entry(struct componentname *cnp);
117 static int ext2_lookup_ino(struct vnode *vdp, struct vnode **vpp,
118 struct componentname *cnp, ino_t *dd_ino);
119
120 static int
121 ext2_is_dot_entry(struct componentname *cnp)
122 {
123 if (cnp->cn_namelen <= 2 && cnp->cn_nameptr[0] == '.' &&
124 (cnp->cn_nameptr[1] == '.' || cnp->cn_nameptr[1] == '\0'))
125 return (1);
126 return (0);
127 }
128
129 /*
130 * Vnode op for reading directories.
131 */
132 int
133 ext2_readdir(struct vop_readdir_args *ap)
134 {
135 struct vnode *vp = ap->a_vp;
136 struct uio *uio = ap->a_uio;
137 struct buf *bp;
138 struct inode *ip;
139 struct ext2fs_direct_2 *dp, *edp;
140 u_long *cookies;
141 struct dirent dstdp;
142 off_t offset, startoffset;
143 size_t readcnt, skipcnt;
144 ssize_t startresid;
145 int ncookies;
146 int DIRBLKSIZ = VTOI(ap->a_vp)->i_e2fs->e2fs_bsize;
147 int error;
148
149 if (uio->uio_offset < 0)
150 return (EINVAL);
151 ip = VTOI(vp);
152 if (ap->a_ncookies != NULL) {
153 if (uio->uio_resid < 0)
154 ncookies = 0;
155 else
156 ncookies = uio->uio_resid;
157 if (uio->uio_offset >= ip->i_size)
158 ncookies = 0;
159 else if (ip->i_size - uio->uio_offset < ncookies)
160 ncookies = ip->i_size - uio->uio_offset;
161 ncookies = ncookies / (offsetof(struct ext2fs_direct_2,
162 e2d_namlen) + 4) + 1;
163 cookies = malloc(ncookies * sizeof(*cookies), M_TEMP, M_WAITOK);
164 *ap->a_ncookies = ncookies;
165 *ap->a_cookies = cookies;
166 } else {
167 ncookies = 0;
168 cookies = NULL;
169 }
170 offset = startoffset = uio->uio_offset;
171 startresid = uio->uio_resid;
172 error = 0;
173 while (error == 0 && uio->uio_resid > 0 &&
174 uio->uio_offset < ip->i_size) {
175 error = ext2_blkatoff(vp, uio->uio_offset, NULL, &bp);
176 if (error)
177 break;
178 if (bp->b_offset + bp->b_bcount > ip->i_size)
179 readcnt = ip->i_size - bp->b_offset;
180 else
181 readcnt = bp->b_bcount;
182 skipcnt = (size_t)(uio->uio_offset - bp->b_offset) &
183 ~(size_t)(DIRBLKSIZ - 1);
184 offset = bp->b_offset + skipcnt;
185 dp = (struct ext2fs_direct_2 *)&bp->b_data[skipcnt];
186 edp = (struct ext2fs_direct_2 *)&bp->b_data[readcnt];
187 while (error == 0 && uio->uio_resid > 0 && dp < edp) {
188 if (dp->e2d_reclen <= offsetof(struct ext2fs_direct_2,
189 e2d_namlen) || (caddr_t)dp + dp->e2d_reclen >
190 (caddr_t)edp) {
191 error = EIO;
192 break;
193 }
194 /*-
195 * "New" ext2fs directory entries differ in 3 ways
196 * from ufs on-disk ones:
197 * - the name is not necessarily NUL-terminated.
198 * - the file type field always exists and always
199 * follows the name length field.
200 * - the file type is encoded in a different way.
201 *
202 * "Old" ext2fs directory entries need no special
203 * conversions, since they are binary compatible
204 * with "new" entries having a file type of 0 (i.e.,
205 * EXT2_FT_UNKNOWN). Splitting the old name length
206 * field didn't make a mess like it did in ufs,
207 * because ext2fs uses a machine-independent disk
208 * layout.
209 */
210 dstdp.d_namlen = dp->e2d_namlen;
211 dstdp.d_type = FTTODT(dp->e2d_type);
212 if (offsetof(struct ext2fs_direct_2, e2d_namlen) +
213 dstdp.d_namlen > dp->e2d_reclen) {
214 error = EIO;
215 break;
216 }
217 if (offset < startoffset || dp->e2d_ino == 0)
218 goto nextentry;
219 dstdp.d_fileno = dp->e2d_ino;
220 dstdp.d_reclen = GENERIC_DIRSIZ(&dstdp);
221 bcopy(dp->e2d_name, dstdp.d_name, dstdp.d_namlen);
222 dirent_terminate(&dstdp);
223 if (dstdp.d_reclen > uio->uio_resid) {
224 if (uio->uio_resid == startresid)
225 error = EINVAL;
226 else
227 error = EJUSTRETURN;
228 break;
229 }
230 /* Advance dp. */
231 error = uiomove((caddr_t)&dstdp, dstdp.d_reclen, uio);
232 if (error)
233 break;
234 if (cookies != NULL) {
235 KASSERT(ncookies > 0,
236 ("ext2_readdir: cookies buffer too small"));
237 *cookies = offset + dp->e2d_reclen;
238 cookies++;
239 ncookies--;
240 }
241 nextentry:
242 offset += dp->e2d_reclen;
243 dp = (struct ext2fs_direct_2 *)((caddr_t)dp +
244 dp->e2d_reclen);
245 }
246 bqrelse(bp);
247 uio->uio_offset = offset;
248 }
249 /* We need to correct uio_offset. */
250 uio->uio_offset = offset;
251 if (error == EJUSTRETURN)
252 error = 0;
253 if (ap->a_ncookies != NULL) {
254 if (error == 0) {
255 ap->a_ncookies -= ncookies;
256 } else {
257 free(*ap->a_cookies, M_TEMP);
258 *ap->a_ncookies = 0;
259 *ap->a_cookies = NULL;
260 }
261 }
262 if (error == 0 && ap->a_eofflag)
263 *ap->a_eofflag = ip->i_size <= uio->uio_offset;
264 return (error);
265 }
266
267 /*
268 * Convert a component of a pathname into a pointer to a locked inode.
269 * This is a very central and rather complicated routine.
270 * If the file system is not maintained in a strict tree hierarchy,
271 * this can result in a deadlock situation (see comments in code below).
272 *
273 * The cnp->cn_nameiop argument is LOOKUP, CREATE, RENAME, or DELETE depending
274 * on whether the name is to be looked up, created, renamed, or deleted.
275 * When CREATE, RENAME, or DELETE is specified, information usable in
276 * creating, renaming, or deleting a directory entry may be calculated.
277 * If flag has LOCKPARENT or'ed into it and the target of the pathname
278 * exists, lookup returns both the target and its parent directory locked.
279 * When creating or renaming and LOCKPARENT is specified, the target may
280 * not be ".". When deleting and LOCKPARENT is specified, the target may
281 * be "."., but the caller must check to ensure it does an vrele and vput
282 * instead of two vputs.
283 *
284 * Overall outline of ext2_lookup:
285 *
286 * search for name in directory, to found or notfound
287 * notfound:
288 * if creating, return locked directory, leaving info on available slots
289 * else return error
290 * found:
291 * if at end of path and deleting, return information to allow delete
292 * if at end of path and rewriting (RENAME and LOCKPARENT), lock target
293 * inode and return info to allow rewrite
294 * if not at end, add name to cache; if at end and neither creating
295 * nor deleting, add name to cache
296 */
297 int
298 ext2_lookup(struct vop_cachedlookup_args *ap)
299 {
300
301 return (ext2_lookup_ino(ap->a_dvp, ap->a_vpp, ap->a_cnp, NULL));
302 }
303
304 static int
305 ext2_lookup_ino(struct vnode *vdp, struct vnode **vpp, struct componentname *cnp,
306 ino_t *dd_ino)
307 {
308 struct inode *dp; /* inode for directory being searched */
309 struct buf *bp; /* a buffer of directory entries */
310 struct ext2fs_direct_2 *ep; /* the current directory entry */
311 int entryoffsetinblock; /* offset of ep in bp's buffer */
312 struct ext2fs_searchslot ss;
313 doff_t i_diroff; /* cached i_diroff value */
314 doff_t i_offset; /* cached i_offset value */
315 int numdirpasses; /* strategy for directory search */
316 doff_t endsearch; /* offset to end directory search */
317 doff_t prevoff; /* prev entry dp->i_offset */
318 struct vnode *pdp; /* saved dp during symlink work */
319 struct vnode *tdp; /* returned by VFS_VGET */
320 doff_t enduseful; /* pointer past last used dir slot */
321 u_long bmask; /* block offset mask */
322 int error;
323 struct ucred *cred = cnp->cn_cred;
324 int flags = cnp->cn_flags;
325 int nameiop = cnp->cn_nameiop;
326 ino_t ino, ino1;
327 int ltype;
328 int entry_found = 0;
329
330 int DIRBLKSIZ = VTOI(vdp)->i_e2fs->e2fs_bsize;
331
332 if (vpp != NULL)
333 *vpp = NULL;
334
335 dp = VTOI(vdp);
336 bmask = VFSTOEXT2(vdp->v_mount)->um_mountp->mnt_stat.f_iosize - 1;
337 restart:
338 bp = NULL;
339 ss.slotoffset = -1;
340
341 /*
342 * We now have a segment name to search for, and a directory to search.
343 *
344 * Suppress search for slots unless creating
345 * file and at end of pathname, in which case
346 * we watch for a place to put the new file in
347 * case it doesn't already exist.
348 */
349 i_diroff = dp->i_diroff;
350 ss.slotstatus = FOUND;
351 ss.slotfreespace = ss.slotsize = ss.slotneeded = 0;
352 if ((nameiop == CREATE || nameiop == RENAME) &&
353 (flags & ISLASTCN)) {
354 ss.slotstatus = NONE;
355 ss.slotneeded = EXT2_DIR_REC_LEN(cnp->cn_namelen);
356 /*
357 * was ss.slotneeded = (sizeof(struct direct) - MAXNAMLEN +
358 * cnp->cn_namelen + 3) &~ 3;
359 */
360 }
361 /*
362 * Try to lookup dir entry using htree directory index.
363 *
364 * If we got an error or we want to find '.' or '..' entry,
365 * we will fall back to linear search.
366 */
367 if (!ext2_is_dot_entry(cnp) && ext2_htree_has_idx(dp)) {
368 numdirpasses = 1;
369 entryoffsetinblock = 0;
370 switch (ext2_htree_lookup(dp, cnp->cn_nameptr, cnp->cn_namelen,
371 &bp, &entryoffsetinblock, &i_offset, &prevoff,
372 &enduseful, &ss)) {
373 case 0:
374 ep = (struct ext2fs_direct_2 *)((char *)bp->b_data +
375 (i_offset & bmask));
376 goto foundentry;
377 case ENOENT:
378 i_offset = roundup2(dp->i_size, DIRBLKSIZ);
379 goto notfound;
380 default:
381 /*
382 * Something failed; just fallback to do a linear
383 * search.
384 */
385 break;
386 }
387 }
388
389 /*
390 * If there is cached information on a previous search of
391 * this directory, pick up where we last left off.
392 * We cache only lookups as these are the most common
393 * and have the greatest payoff. Caching CREATE has little
394 * benefit as it usually must search the entire directory
395 * to determine that the entry does not exist. Caching the
396 * location of the last DELETE or RENAME has not reduced
397 * profiling time and hence has been removed in the interest
398 * of simplicity.
399 */
400 if (nameiop != LOOKUP || i_diroff == 0 ||
401 i_diroff > dp->i_size) {
402 entryoffsetinblock = 0;
403 i_offset = 0;
404 numdirpasses = 1;
405 } else {
406 i_offset = i_diroff;
407 if ((entryoffsetinblock = i_offset & bmask) &&
408 (error = ext2_blkatoff(vdp, (off_t)i_offset, NULL,
409 &bp)))
410 return (error);
411 numdirpasses = 2;
412 nchstats.ncs_2passes++;
413 }
414 prevoff = i_offset;
415 endsearch = roundup2(dp->i_size, DIRBLKSIZ);
416 enduseful = 0;
417
418 searchloop:
419 while (i_offset < endsearch) {
420 /*
421 * If necessary, get the next directory block.
422 */
423 if (bp != NULL)
424 brelse(bp);
425 error = ext2_blkatoff(vdp, (off_t)i_offset, NULL, &bp);
426 if (error != 0)
427 return (error);
428 entryoffsetinblock = 0;
429 /*
430 * If still looking for a slot, and at a DIRBLKSIZE
431 * boundary, have to start looking for free space again.
432 */
433 if (ss.slotstatus == NONE &&
434 (entryoffsetinblock & (DIRBLKSIZ - 1)) == 0) {
435 ss.slotoffset = -1;
436 ss.slotfreespace = 0;
437 }
438 error = ext2_search_dirblock(dp, bp->b_data, &entry_found,
439 cnp->cn_nameptr, cnp->cn_namelen,
440 &entryoffsetinblock, &i_offset, &prevoff,
441 &enduseful, &ss);
442 if (error != 0) {
443 brelse(bp);
444 return (error);
445 }
446 if (entry_found) {
447 ep = (struct ext2fs_direct_2 *)((char *)bp->b_data +
448 (entryoffsetinblock & bmask));
449 foundentry:
450 ino = ep->e2d_ino;
451 goto found;
452 }
453 }
454 notfound:
455 /*
456 * If we started in the middle of the directory and failed
457 * to find our target, we must check the beginning as well.
458 */
459 if (numdirpasses == 2) {
460 numdirpasses--;
461 i_offset = 0;
462 endsearch = i_diroff;
463 goto searchloop;
464 }
465 if (bp != NULL)
466 brelse(bp);
467 /*
468 * If creating, and at end of pathname and current
469 * directory has not been removed, then can consider
470 * allowing file to be created.
471 */
472 if ((nameiop == CREATE || nameiop == RENAME) &&
473 (flags & ISLASTCN) && dp->i_nlink != 0) {
474 /*
475 * Access for write is interpreted as allowing
476 * creation of files in the directory.
477 */
478 if ((error = VOP_ACCESS(vdp, VWRITE, cred, cnp->cn_thread)) != 0)
479 return (error);
480 /*
481 * Return an indication of where the new directory
482 * entry should be put. If we didn't find a slot,
483 * then set dp->i_count to 0 indicating
484 * that the new slot belongs at the end of the
485 * directory. If we found a slot, then the new entry
486 * can be put in the range from dp->i_offset to
487 * dp->i_offset + dp->i_count.
488 */
489 if (ss.slotstatus == NONE) {
490 dp->i_offset = roundup2(dp->i_size, DIRBLKSIZ);
491 dp->i_count = 0;
492 enduseful = dp->i_offset;
493 } else {
494 dp->i_offset = ss.slotoffset;
495 dp->i_count = ss.slotsize;
496 if (enduseful < ss.slotoffset + ss.slotsize)
497 enduseful = ss.slotoffset + ss.slotsize;
498 }
499 dp->i_endoff = roundup2(enduseful, DIRBLKSIZ);
500 /*
501 * We return with the directory locked, so that
502 * the parameters we set up above will still be
503 * valid if we actually decide to do a direnter().
504 * We return ni_vp == NULL to indicate that the entry
505 * does not currently exist; we leave a pointer to
506 * the (locked) directory inode in ndp->ni_dvp.
507 * The pathname buffer is saved so that the name
508 * can be obtained later.
509 *
510 * NB - if the directory is unlocked, then this
511 * information cannot be used.
512 */
513 cnp->cn_flags |= SAVENAME;
514 return (EJUSTRETURN);
515 }
516 /*
517 * Insert name into cache (as non-existent) if appropriate.
518 */
519 if ((cnp->cn_flags & MAKEENTRY) != 0)
520 cache_enter(vdp, NULL, cnp);
521 return (ENOENT);
522
523 found:
524 if (dd_ino != NULL)
525 *dd_ino = ino;
526 if (numdirpasses == 2)
527 nchstats.ncs_pass2++;
528 /*
529 * Check that directory length properly reflects presence
530 * of this entry.
531 */
532 if (entryoffsetinblock + EXT2_DIR_REC_LEN(ep->e2d_namlen)
533 > dp->i_size) {
534 ext2_dirbad(dp, i_offset, "i_size too small");
535 dp->i_size = entryoffsetinblock + EXT2_DIR_REC_LEN(ep->e2d_namlen);
536 dp->i_flag |= IN_CHANGE | IN_UPDATE;
537 }
538 brelse(bp);
539
540 /*
541 * Found component in pathname.
542 * If the final component of path name, save information
543 * in the cache as to where the entry was found.
544 */
545 if ((flags & ISLASTCN) && nameiop == LOOKUP)
546 dp->i_diroff = rounddown2(i_offset, DIRBLKSIZ);
547 /*
548 * If deleting, and at end of pathname, return
549 * parameters which can be used to remove file.
550 */
551 if (nameiop == DELETE && (flags & ISLASTCN)) {
552 if (flags & LOCKPARENT)
553 ASSERT_VOP_ELOCKED(vdp, __FUNCTION__);
554 /*
555 * Write access to directory required to delete files.
556 */
557 if ((error = VOP_ACCESS(vdp, VWRITE, cred, cnp->cn_thread)) != 0)
558 return (error);
559 /*
560 * Return pointer to current entry in dp->i_offset,
561 * and distance past previous entry (if there
562 * is a previous entry in this block) in dp->i_count.
563 * Save directory inode pointer in ndp->ni_dvp for dirremove().
564 *
565 * Technically we shouldn't be setting these in the
566 * WANTPARENT case (first lookup in rename()), but any
567 * lookups that will result in directory changes will
568 * overwrite these.
569 */
570 dp->i_offset = i_offset;
571 if ((dp->i_offset & (DIRBLKSIZ - 1)) == 0)
572 dp->i_count = 0;
573 else
574 dp->i_count = dp->i_offset - prevoff;
575 if (dd_ino != NULL)
576 return (0);
577 if (dp->i_number == ino) {
578 VREF(vdp);
579 *vpp = vdp;
580 return (0);
581 }
582 if ((error = VFS_VGET(vdp->v_mount, ino, LK_EXCLUSIVE,
583 &tdp)) != 0)
584 return (error);
585 /*
586 * If directory is "sticky", then user must own
587 * the directory, or the file in it, else she
588 * may not delete it (unless she's root). This
589 * implements append-only directories.
590 */
591 if ((dp->i_mode & ISVTX) &&
592 cred->cr_uid != 0 &&
593 cred->cr_uid != dp->i_uid &&
594 VTOI(tdp)->i_uid != cred->cr_uid) {
595 vput(tdp);
596 return (EPERM);
597 }
598 *vpp = tdp;
599 return (0);
600 }
601
602 /*
603 * If rewriting (RENAME), return the inode and the
604 * information required to rewrite the present directory
605 * Must get inode of directory entry to verify it's a
606 * regular file, or empty directory.
607 */
608 if (nameiop == RENAME && (flags & ISLASTCN)) {
609 if ((error = VOP_ACCESS(vdp, VWRITE, cred, cnp->cn_thread)) != 0)
610 return (error);
611 /*
612 * Careful about locking second inode.
613 * This can only occur if the target is ".".
614 */
615 dp->i_offset = i_offset;
616 if (dp->i_number == ino)
617 return (EISDIR);
618 if (dd_ino != NULL)
619 return (0);
620 if ((error = VFS_VGET(vdp->v_mount, ino, LK_EXCLUSIVE,
621 &tdp)) != 0)
622 return (error);
623 *vpp = tdp;
624 cnp->cn_flags |= SAVENAME;
625 return (0);
626 }
627 if (dd_ino != NULL)
628 return (0);
629
630 /*
631 * Step through the translation in the name. We do not `vput' the
632 * directory because we may need it again if a symbolic link
633 * is relative to the current directory. Instead we save it
634 * unlocked as "pdp". We must get the target inode before unlocking
635 * the directory to insure that the inode will not be removed
636 * before we get it. We prevent deadlock by always fetching
637 * inodes from the root, moving down the directory tree. Thus
638 * when following backward pointers ".." we must unlock the
639 * parent directory before getting the requested directory.
640 * There is a potential race condition here if both the current
641 * and parent directories are removed before the VFS_VGET for the
642 * inode associated with ".." returns. We hope that this occurs
643 * infrequently since we cannot avoid this race condition without
644 * implementing a sophisticated deadlock detection algorithm.
645 * Note also that this simple deadlock detection scheme will not
646 * work if the file system has any hard links other than ".."
647 * that point backwards in the directory structure.
648 */
649 pdp = vdp;
650 if (flags & ISDOTDOT) {
651 error = vn_vget_ino(pdp, ino, cnp->cn_lkflags, &tdp);
652 if (pdp->v_iflag & VI_DOOMED) {
653 if (error == 0)
654 vput(tdp);
655 error = ENOENT;
656 }
657 if (error)
658 return (error);
659 /*
660 * Recheck that ".." entry in the vdp directory points
661 * to the inode we looked up before vdp lock was
662 * dropped.
663 */
664 error = ext2_lookup_ino(pdp, NULL, cnp, &ino1);
665 if (error) {
666 vput(tdp);
667 return (error);
668 }
669 if (ino1 != ino) {
670 vput(tdp);
671 goto restart;
672 }
673 *vpp = tdp;
674 } else if (dp->i_number == ino) {
675 VREF(vdp); /* we want ourself, ie "." */
676 /*
677 * When we lookup "." we still can be asked to lock it
678 * differently.
679 */
680 ltype = cnp->cn_lkflags & LK_TYPE_MASK;
681 if (ltype != VOP_ISLOCKED(vdp)) {
682 if (ltype == LK_EXCLUSIVE)
683 vn_lock(vdp, LK_UPGRADE | LK_RETRY);
684 else /* if (ltype == LK_SHARED) */
685 vn_lock(vdp, LK_DOWNGRADE | LK_RETRY);
686 }
687 *vpp = vdp;
688 } else {
689 if ((error = VFS_VGET(vdp->v_mount, ino, cnp->cn_lkflags,
690 &tdp)) != 0)
691 return (error);
692 *vpp = tdp;
693 }
694
695 /*
696 * Insert name into cache if appropriate.
697 */
698 if (cnp->cn_flags & MAKEENTRY)
699 cache_enter(vdp, *vpp, cnp);
700 return (0);
701 }
702
703 int
704 ext2_search_dirblock(struct inode *ip, void *data, int *foundp,
705 const char *name, int namelen, int *entryoffsetinblockp,
706 doff_t *offp, doff_t *prevoffp, doff_t *endusefulp,
707 struct ext2fs_searchslot *ssp)
708 {
709 struct vnode *vdp;
710 struct ext2fs_direct_2 *ep, *top;
711 uint32_t bsize = ip->i_e2fs->e2fs_bsize;
712 int offset = *entryoffsetinblockp;
713 int namlen;
714
715 vdp = ITOV(ip);
716
717 ep = (struct ext2fs_direct_2 *)((char *)data + offset);
718 top = (struct ext2fs_direct_2 *)((char *)data +
719 bsize - EXT2_DIR_REC_LEN(0));
720
721 while (ep < top) {
722 /*
723 * Full validation checks are slow, so we only check
724 * enough to insure forward progress through the
725 * directory. Complete checks can be run by setting
726 * "vfs.e2fs.dirchk" to be true.
727 */
728 if (ep->e2d_reclen == 0 ||
729 (dirchk && ext2_dirbadentry(vdp, ep, offset))) {
730 int i;
731
732 ext2_dirbad(ip, *offp, "mangled entry");
733 i = bsize - (offset & (bsize - 1));
734 *offp += i;
735 offset += i;
736 continue;
737 }
738
739 /*
740 * If an appropriate sized slot has not yet been found,
741 * check to see if one is available. Also accumulate space
742 * in the current block so that we can determine if
743 * compaction is viable.
744 */
745 if (ssp->slotstatus != FOUND) {
746 int size = ep->e2d_reclen;
747
748 if (ep->e2d_ino != 0)
749 size -= EXT2_DIR_REC_LEN(ep->e2d_namlen);
750 if (size > 0) {
751 if (size >= ssp->slotneeded) {
752 ssp->slotstatus = FOUND;
753 ssp->slotoffset = *offp;
754 ssp->slotsize = ep->e2d_reclen;
755 } else if (ssp->slotstatus == NONE) {
756 ssp->slotfreespace += size;
757 if (ssp->slotoffset == -1)
758 ssp->slotoffset = *offp;
759 if (ssp->slotfreespace >= ssp->slotneeded) {
760 ssp->slotstatus = COMPACT;
761 ssp->slotsize = *offp +
762 ep->e2d_reclen -
763 ssp->slotoffset;
764 }
765 }
766 }
767 }
768 /*
769 * Check for a name match.
770 */
771 if (ep->e2d_ino) {
772 namlen = ep->e2d_namlen;
773 if (namlen == namelen &&
774 !bcmp(name, ep->e2d_name, (unsigned)namlen)) {
775 /*
776 * Save directory entry's inode number and
777 * reclen in ndp->ni_ufs area, and release
778 * directory buffer.
779 */
780 *foundp = 1;
781 return (0);
782 }
783 }
784 *prevoffp = *offp;
785 *offp += ep->e2d_reclen;
786 offset += ep->e2d_reclen;
787 *entryoffsetinblockp = offset;
788 if (ep->e2d_ino)
789 *endusefulp = *offp;
790 /*
791 * Get pointer to the next entry.
792 */
793 ep = (struct ext2fs_direct_2 *)((char *)data + offset);
794 }
795
796 return (0);
797 }
798
799 void
800 ext2_dirbad(struct inode *ip, doff_t offset, char *how)
801 {
802 struct mount *mp;
803
804 mp = ITOV(ip)->v_mount;
805 if ((mp->mnt_flag & MNT_RDONLY) == 0)
806 panic("ext2_dirbad: %s: bad dir ino %ju at offset %ld: %s\n",
807 mp->mnt_stat.f_mntonname, (uintmax_t)ip->i_number,
808 (long)offset, how);
809 else
810 (void)printf("%s: bad dir ino %ju at offset %ld: %s\n",
811 mp->mnt_stat.f_mntonname, (uintmax_t)ip->i_number,
812 (long)offset, how);
813
814 }
815
816 /*
817 * Do consistency checking on a directory entry:
818 * record length must be multiple of 4
819 * entry must fit in rest of its DIRBLKSIZ block
820 * record must be large enough to contain entry
821 * name is not longer than MAXNAMLEN
822 * name must be as long as advertised, and null terminated
823 */
824 /*
825 * changed so that it confirms to ext2_check_dir_entry
826 */
827 static int
828 ext2_dirbadentry(struct vnode *dp, struct ext2fs_direct_2 *de,
829 int entryoffsetinblock)
830 {
831 int DIRBLKSIZ = VTOI(dp)->i_e2fs->e2fs_bsize;
832
833 char *error_msg = NULL;
834
835 if (de->e2d_reclen < EXT2_DIR_REC_LEN(1))
836 error_msg = "rec_len is smaller than minimal";
837 else if (de->e2d_reclen % 4 != 0)
838 error_msg = "rec_len % 4 != 0";
839 else if (de->e2d_reclen < EXT2_DIR_REC_LEN(de->e2d_namlen))
840 error_msg = "reclen is too small for name_len";
841 else if (entryoffsetinblock + de->e2d_reclen > DIRBLKSIZ)
842 error_msg = "directory entry across blocks";
843 /* else LATER
844 if (de->inode > dir->i_sb->u.ext2_sb.s_es->s_inodes_count)
845 error_msg = "inode out of bounds";
846 */
847
848 if (error_msg != NULL) {
849 printf("bad directory entry: %s\n", error_msg);
850 printf("offset=%d, inode=%lu, rec_len=%u, name_len=%u\n",
851 entryoffsetinblock, (unsigned long)de->e2d_ino,
852 de->e2d_reclen, de->e2d_namlen);
853 }
854 return error_msg == NULL ? 0 : 1;
855 }
856
857 /*
858 * Write a directory entry after a call to namei, using the parameters
859 * that it left in nameidata. The argument ip is the inode which the new
860 * directory entry will refer to. Dvp is a pointer to the directory to
861 * be written, which was left locked by namei. Remaining parameters
862 * (dp->i_offset, dp->i_count) indicate how the space for the new
863 * entry is to be obtained.
864 */
865 int
866 ext2_direnter(struct inode *ip, struct vnode *dvp, struct componentname *cnp)
867 {
868 struct inode *dp;
869 struct ext2fs_direct_2 newdir;
870 struct iovec aiov;
871 struct uio auio;
872 int error, newentrysize;
873 int DIRBLKSIZ = ip->i_e2fs->e2fs_bsize;
874
875
876 #ifdef INVARIANTS
877 if ((cnp->cn_flags & SAVENAME) == 0)
878 panic("ext2_direnter: missing name");
879 #endif
880 dp = VTOI(dvp);
881 newdir.e2d_ino = ip->i_number;
882 newdir.e2d_namlen = cnp->cn_namelen;
883 if (EXT2_HAS_INCOMPAT_FEATURE(ip->i_e2fs,
884 EXT2F_INCOMPAT_FTYPE))
885 newdir.e2d_type = DTTOFT(IFTODT(ip->i_mode));
886 else
887 newdir.e2d_type = EXT2_FT_UNKNOWN;
888 bcopy(cnp->cn_nameptr, newdir.e2d_name, (unsigned)cnp->cn_namelen + 1);
889 newentrysize = EXT2_DIR_REC_LEN(newdir.e2d_namlen);
890
891 if (ext2_htree_has_idx(dp)) {
892 error = ext2_htree_add_entry(dvp, &newdir, cnp);
893 if (error) {
894 dp->i_flag &= ~IN_E3INDEX;
895 dp->i_flag |= IN_CHANGE | IN_UPDATE;
896 }
897 return (error);
898 }
899
900 if (EXT2_HAS_COMPAT_FEATURE(ip->i_e2fs, EXT2F_COMPAT_DIRHASHINDEX) &&
901 !ext2_htree_has_idx(dp)) {
902 if ((dp->i_size / DIRBLKSIZ) == 1 &&
903 dp->i_offset == DIRBLKSIZ) {
904 /*
905 * Making indexed directory when one block is not
906 * enough to save all entries.
907 */
908 return ext2_htree_create_index(dvp, cnp, &newdir);
909 }
910 }
911
912 if (dp->i_count == 0) {
913 /*
914 * If dp->i_count is 0, then namei could find no
915 * space in the directory. Here, dp->i_offset will
916 * be on a directory block boundary and we will write the
917 * new entry into a fresh block.
918 */
919 if (dp->i_offset & (DIRBLKSIZ - 1))
920 panic("ext2_direnter: newblk");
921 auio.uio_offset = dp->i_offset;
922 newdir.e2d_reclen = DIRBLKSIZ;
923 auio.uio_resid = newentrysize;
924 aiov.iov_len = newentrysize;
925 aiov.iov_base = (caddr_t)&newdir;
926 auio.uio_iov = &aiov;
927 auio.uio_iovcnt = 1;
928 auio.uio_rw = UIO_WRITE;
929 auio.uio_segflg = UIO_SYSSPACE;
930 auio.uio_td = (struct thread *)0;
931 error = VOP_WRITE(dvp, &auio, IO_SYNC, cnp->cn_cred);
932 if (DIRBLKSIZ >
933 VFSTOEXT2(dvp->v_mount)->um_mountp->mnt_stat.f_bsize)
934 /* XXX should grow with balloc() */
935 panic("ext2_direnter: frag size");
936 else if (!error) {
937 dp->i_size = roundup2(dp->i_size, DIRBLKSIZ);
938 dp->i_flag |= IN_CHANGE;
939 }
940 return (error);
941 }
942
943 error = ext2_add_entry(dvp, &newdir);
944 if (!error && dp->i_endoff && dp->i_endoff < dp->i_size)
945 error = ext2_truncate(dvp, (off_t)dp->i_endoff, IO_SYNC,
946 cnp->cn_cred, cnp->cn_thread);
947 return (error);
948 }
949
950 /*
951 * Insert an entry into the directory block.
952 * Compact the contents.
953 */
954 int
955 ext2_add_entry(struct vnode *dvp, struct ext2fs_direct_2 *entry)
956 {
957 struct ext2fs_direct_2 *ep, *nep;
958 struct inode *dp;
959 struct buf *bp;
960 u_int dsize;
961 int error, loc, newentrysize, spacefree;
962 char *dirbuf;
963
964 dp = VTOI(dvp);
965
966 /*
967 * If dp->i_count is non-zero, then namei found space
968 * for the new entry in the range dp->i_offset to
969 * dp->i_offset + dp->i_count in the directory.
970 * To use this space, we may have to compact the entries located
971 * there, by copying them together towards the beginning of the
972 * block, leaving the free space in one usable chunk at the end.
973 */
974
975 /*
976 * Increase size of directory if entry eats into new space.
977 * This should never push the size past a new multiple of
978 * DIRBLKSIZE.
979 *
980 * N.B. - THIS IS AN ARTIFACT OF 4.2 AND SHOULD NEVER HAPPEN.
981 */
982 if (dp->i_offset + dp->i_count > dp->i_size)
983 dp->i_size = dp->i_offset + dp->i_count;
984 /*
985 * Get the block containing the space for the new directory entry.
986 */
987 if ((error = ext2_blkatoff(dvp, (off_t)dp->i_offset, &dirbuf,
988 &bp)) != 0)
989 return (error);
990 /*
991 * Find space for the new entry. In the simple case, the entry at
992 * offset base will have the space. If it does not, then namei
993 * arranged that compacting the region dp->i_offset to
994 * dp->i_offset + dp->i_count would yield the
995 * space.
996 */
997 newentrysize = EXT2_DIR_REC_LEN(entry->e2d_namlen);
998 ep = (struct ext2fs_direct_2 *)dirbuf;
999 dsize = EXT2_DIR_REC_LEN(ep->e2d_namlen);
1000 spacefree = ep->e2d_reclen - dsize;
1001 for (loc = ep->e2d_reclen; loc < dp->i_count; ) {
1002 nep = (struct ext2fs_direct_2 *)(dirbuf + loc);
1003 if (ep->e2d_ino) {
1004 /* trim the existing slot */
1005 ep->e2d_reclen = dsize;
1006 ep = (struct ext2fs_direct_2 *)((char *)ep + dsize);
1007 } else {
1008 /* overwrite; nothing there; header is ours */
1009 spacefree += dsize;
1010 }
1011 dsize = EXT2_DIR_REC_LEN(nep->e2d_namlen);
1012 spacefree += nep->e2d_reclen - dsize;
1013 loc += nep->e2d_reclen;
1014 bcopy((caddr_t)nep, (caddr_t)ep, dsize);
1015 }
1016 /*
1017 * Update the pointer fields in the previous entry (if any),
1018 * copy in the new entry, and write out the block.
1019 */
1020 if (ep->e2d_ino == 0) {
1021 if (spacefree + dsize < newentrysize)
1022 panic("ext2_direnter: compact1");
1023 entry->e2d_reclen = spacefree + dsize;
1024 } else {
1025 if (spacefree < newentrysize)
1026 panic("ext2_direnter: compact2");
1027 entry->e2d_reclen = spacefree;
1028 ep->e2d_reclen = dsize;
1029 ep = (struct ext2fs_direct_2 *)((char *)ep + dsize);
1030 }
1031 bcopy((caddr_t)entry, (caddr_t)ep, (u_int)newentrysize);
1032 if (DOINGASYNC(dvp)) {
1033 bdwrite(bp);
1034 error = 0;
1035 } else {
1036 error = bwrite(bp);
1037 }
1038 dp->i_flag |= IN_CHANGE | IN_UPDATE;
1039 return (error);
1040 }
1041
1042 /*
1043 * Remove a directory entry after a call to namei, using
1044 * the parameters which it left in nameidata. The entry
1045 * dp->i_offset contains the offset into the directory of the
1046 * entry to be eliminated. The dp->i_count field contains the
1047 * size of the previous record in the directory. If this
1048 * is 0, the first entry is being deleted, so we need only
1049 * zero the inode number to mark the entry as free. If the
1050 * entry is not the first in the directory, we must reclaim
1051 * the space of the now empty record by adding the record size
1052 * to the size of the previous entry.
1053 */
1054 int
1055 ext2_dirremove(struct vnode *dvp, struct componentname *cnp)
1056 {
1057 struct inode *dp;
1058 struct ext2fs_direct_2 *ep, *rep;
1059 struct buf *bp;
1060 int error;
1061
1062 dp = VTOI(dvp);
1063 if (dp->i_count == 0) {
1064 /*
1065 * First entry in block: set d_ino to zero.
1066 */
1067 if ((error =
1068 ext2_blkatoff(dvp, (off_t)dp->i_offset, (char **)&ep,
1069 &bp)) != 0)
1070 return (error);
1071 ep->e2d_ino = 0;
1072 error = bwrite(bp);
1073 dp->i_flag |= IN_CHANGE | IN_UPDATE;
1074 return (error);
1075 }
1076 /*
1077 * Collapse new free space into previous entry.
1078 */
1079 if ((error = ext2_blkatoff(dvp, (off_t)(dp->i_offset - dp->i_count),
1080 (char **)&ep, &bp)) != 0)
1081 return (error);
1082
1083 /* Set 'rep' to the entry being removed. */
1084 if (dp->i_count == 0)
1085 rep = ep;
1086 else
1087 rep = (struct ext2fs_direct_2 *)((char *)ep + ep->e2d_reclen);
1088 ep->e2d_reclen += rep->e2d_reclen;
1089 if (DOINGASYNC(dvp) && dp->i_count != 0)
1090 bdwrite(bp);
1091 else
1092 error = bwrite(bp);
1093 dp->i_flag |= IN_CHANGE | IN_UPDATE;
1094 return (error);
1095 }
1096
1097 /*
1098 * Rewrite an existing directory entry to point at the inode
1099 * supplied. The parameters describing the directory entry are
1100 * set up by a call to namei.
1101 */
1102 int
1103 ext2_dirrewrite(struct inode *dp, struct inode *ip, struct componentname *cnp)
1104 {
1105 struct buf *bp;
1106 struct ext2fs_direct_2 *ep;
1107 struct vnode *vdp = ITOV(dp);
1108 int error;
1109
1110 if ((error = ext2_blkatoff(vdp, (off_t)dp->i_offset, (char **)&ep,
1111 &bp)) != 0)
1112 return (error);
1113 ep->e2d_ino = ip->i_number;
1114 if (EXT2_HAS_INCOMPAT_FEATURE(ip->i_e2fs,
1115 EXT2F_INCOMPAT_FTYPE))
1116 ep->e2d_type = DTTOFT(IFTODT(ip->i_mode));
1117 else
1118 ep->e2d_type = EXT2_FT_UNKNOWN;
1119 error = bwrite(bp);
1120 dp->i_flag |= IN_CHANGE | IN_UPDATE;
1121 return (error);
1122 }
1123
1124 /*
1125 * Check if a directory is empty or not.
1126 * Inode supplied must be locked.
1127 *
1128 * Using a struct dirtemplate here is not precisely
1129 * what we want, but better than using a struct direct.
1130 *
1131 * NB: does not handle corrupted directories.
1132 */
1133 int
1134 ext2_dirempty(struct inode *ip, ino_t parentino, struct ucred *cred)
1135 {
1136 off_t off;
1137 struct dirtemplate dbuf;
1138 struct ext2fs_direct_2 *dp = (struct ext2fs_direct_2 *)&dbuf;
1139 int error, namlen;
1140 ssize_t count;
1141 #define MINDIRSIZ (sizeof(struct dirtemplate) / 2)
1142
1143 for (off = 0; off < ip->i_size; off += dp->e2d_reclen) {
1144 error = vn_rdwr(UIO_READ, ITOV(ip), (caddr_t)dp, MINDIRSIZ,
1145 off, UIO_SYSSPACE, IO_NODELOCKED | IO_NOMACCHECK, cred,
1146 NOCRED, &count, (struct thread *)0);
1147 /*
1148 * Since we read MINDIRSIZ, residual must
1149 * be 0 unless we're at end of file.
1150 */
1151 if (error || count != 0)
1152 return (0);
1153 /* avoid infinite loops */
1154 if (dp->e2d_reclen == 0)
1155 return (0);
1156 /* skip empty entries */
1157 if (dp->e2d_ino == 0)
1158 continue;
1159 /* accept only "." and ".." */
1160 namlen = dp->e2d_namlen;
1161 if (namlen > 2)
1162 return (0);
1163 if (dp->e2d_name[0] != '.')
1164 return (0);
1165 /*
1166 * At this point namlen must be 1 or 2.
1167 * 1 implies ".", 2 implies ".." if second
1168 * char is also "."
1169 */
1170 if (namlen == 1)
1171 continue;
1172 if (dp->e2d_name[1] == '.' && dp->e2d_ino == parentino)
1173 continue;
1174 return (0);
1175 }
1176 return (1);
1177 }
1178
1179 /*
1180 * Check if source directory is in the path of the target directory.
1181 * Target is supplied locked, source is unlocked.
1182 * The target is always vput before returning.
1183 */
1184 int
1185 ext2_checkpath(struct inode *source, struct inode *target, struct ucred *cred)
1186 {
1187 struct vnode *vp;
1188 int error, namlen;
1189 struct dirtemplate dirbuf;
1190
1191 vp = ITOV(target);
1192 if (target->i_number == source->i_number) {
1193 error = EEXIST;
1194 goto out;
1195 }
1196 if (target->i_number == EXT2_ROOTINO) {
1197 error = 0;
1198 goto out;
1199 }
1200
1201 for (;;) {
1202 if (vp->v_type != VDIR) {
1203 error = ENOTDIR;
1204 break;
1205 }
1206 error = vn_rdwr(UIO_READ, vp, (caddr_t)&dirbuf,
1207 sizeof(struct dirtemplate), (off_t)0, UIO_SYSSPACE,
1208 IO_NODELOCKED | IO_NOMACCHECK, cred, NOCRED, NULL,
1209 NULL);
1210 if (error != 0)
1211 break;
1212 namlen = dirbuf.dotdot_type; /* like ufs little-endian */
1213 if (namlen != 2 ||
1214 dirbuf.dotdot_name[0] != '.' ||
1215 dirbuf.dotdot_name[1] != '.') {
1216 error = ENOTDIR;
1217 break;
1218 }
1219 if (dirbuf.dotdot_ino == source->i_number) {
1220 error = EINVAL;
1221 break;
1222 }
1223 if (dirbuf.dotdot_ino == EXT2_ROOTINO)
1224 break;
1225 vput(vp);
1226 if ((error = VFS_VGET(vp->v_mount, dirbuf.dotdot_ino,
1227 LK_EXCLUSIVE, &vp)) != 0) {
1228 vp = NULL;
1229 break;
1230 }
1231 }
1232
1233 out:
1234 if (error == ENOTDIR)
1235 printf("checkpath: .. not a directory\n");
1236 if (vp != NULL)
1237 vput(vp);
1238 return (error);
1239 }
Cache object: 86ad45421006160a27af794989c09c34
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