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 * SPDX-License-Identifier: BSD-3-Clause
9 *
10 * Copyright (c) 1989, 1993
11 * The Regents of the University of California. All rights reserved.
12 * (c) UNIX System Laboratories, Inc.
13 * All or some portions of this file are derived from material licensed
14 * to the University of California by American Telephone and Telegraph
15 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
16 * the permission of UNIX System Laboratories, Inc.
17 *
18 * Redistribution and use in source and binary forms, with or without
19 * modification, are permitted provided that the following conditions
20 * are met:
21 * 1. Redistributions of source code must retain the above copyright
22 * notice, this list of conditions and the following disclaimer.
23 * 2. Redistributions in binary form must reproduce the above copyright
24 * notice, this list of conditions and the following disclaimer in the
25 * documentation and/or other materials provided with the distribution.
26 * 3. Neither the name of the University nor the names of its contributors
27 * may be used to endorse or promote products derived from this software
28 * without specific prior written permission.
29 *
30 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
31 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
32 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
33 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
34 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
35 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
36 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
37 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
38 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
39 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
40 * SUCH DAMAGE.
41 *
42 * @(#)ufs_lookup.c 8.6 (Berkeley) 4/1/94
43 */
44
45 #include <sys/param.h>
46 #include <sys/systm.h>
47 #include <sys/namei.h>
48 #include <sys/bio.h>
49 #include <sys/buf.h>
50 #include <sys/endian.h>
51 #include <sys/mount.h>
52 #include <sys/vnode.h>
53 #include <sys/malloc.h>
54 #include <sys/dirent.h>
55 #include <sys/sdt.h>
56 #include <sys/sysctl.h>
57
58 #include <ufs/ufs/dir.h>
59
60 #include <fs/ext2fs/fs.h>
61 #include <fs/ext2fs/inode.h>
62 #include <fs/ext2fs/ext2_mount.h>
63 #include <fs/ext2fs/ext2fs.h>
64 #include <fs/ext2fs/ext2_dinode.h>
65 #include <fs/ext2fs/ext2_dir.h>
66 #include <fs/ext2fs/ext2_extern.h>
67 #include <fs/ext2fs/fs.h>
68
69 SDT_PROVIDER_DECLARE(ext2fs);
70 /*
71 * ext2fs trace probe:
72 * arg0: verbosity. Higher numbers give more verbose messages
73 * arg1: Textual message
74 */
75 SDT_PROBE_DEFINE2(ext2fs, , lookup, trace, "int", "char*");
76 SDT_PROBE_DEFINE4(ext2fs, , trace, ext2_dirbad_error,
77 "char*", "ino_t", "doff_t", "char*");
78 SDT_PROBE_DEFINE5(ext2fs, , trace, ext2_dirbadentry_error,
79 "char*", "int", "uint32_t", "uint16_t", "uint8_t");
80
81 #ifdef INVARIANTS
82 static int dirchk = 1;
83 #else
84 static int dirchk = 0;
85 #endif
86
87 static SYSCTL_NODE(_vfs, OID_AUTO, e2fs, CTLFLAG_RD | CTLFLAG_MPSAFE, 0,
88 "EXT2FS filesystem");
89 SYSCTL_INT(_vfs_e2fs, OID_AUTO, dircheck, CTLFLAG_RW, &dirchk, 0, "");
90
91 /*
92 DIRBLKSIZE in ffs is DEV_BSIZE (in most cases 512)
93 while it is the native blocksize in ext2fs - thus, a #define
94 is no longer appropriate
95 */
96 #undef DIRBLKSIZ
97
98 static u_char ext2_ft_to_dt[] = {
99 DT_UNKNOWN, /* EXT2_FT_UNKNOWN */
100 DT_REG, /* EXT2_FT_REG_FILE */
101 DT_DIR, /* EXT2_FT_DIR */
102 DT_CHR, /* EXT2_FT_CHRDEV */
103 DT_BLK, /* EXT2_FT_BLKDEV */
104 DT_FIFO, /* EXT2_FT_FIFO */
105 DT_SOCK, /* EXT2_FT_SOCK */
106 DT_LNK, /* EXT2_FT_SYMLINK */
107 };
108 #define FTTODT(ft) \
109 ((ft) < nitems(ext2_ft_to_dt) ? ext2_ft_to_dt[(ft)] : DT_UNKNOWN)
110
111 static u_char dt_to_ext2_ft[] = {
112 EXT2_FT_UNKNOWN, /* DT_UNKNOWN */
113 EXT2_FT_FIFO, /* DT_FIFO */
114 EXT2_FT_CHRDEV, /* DT_CHR */
115 EXT2_FT_UNKNOWN, /* unused */
116 EXT2_FT_DIR, /* DT_DIR */
117 EXT2_FT_UNKNOWN, /* unused */
118 EXT2_FT_BLKDEV, /* DT_BLK */
119 EXT2_FT_UNKNOWN, /* unused */
120 EXT2_FT_REG_FILE, /* DT_REG */
121 EXT2_FT_UNKNOWN, /* unused */
122 EXT2_FT_SYMLINK, /* DT_LNK */
123 EXT2_FT_UNKNOWN, /* unused */
124 EXT2_FT_SOCK, /* DT_SOCK */
125 EXT2_FT_UNKNOWN, /* unused */
126 EXT2_FT_UNKNOWN, /* DT_WHT */
127 };
128 #define DTTOFT(dt) \
129 ((dt) < nitems(dt_to_ext2_ft) ? dt_to_ext2_ft[(dt)] : EXT2_FT_UNKNOWN)
130
131 static int ext2_dirbadentry(struct vnode *dp, struct ext2fs_direct_2 *de,
132 int entryoffsetinblock);
133 static int ext2_is_dot_entry(struct componentname *cnp);
134 static int ext2_lookup_ino(struct vnode *vdp, struct vnode **vpp,
135 struct componentname *cnp, ino_t *dd_ino);
136
137 static int
ext2_is_dot_entry(struct componentname * cnp)138 ext2_is_dot_entry(struct componentname *cnp)
139 {
140 if (cnp->cn_namelen <= 2 && cnp->cn_nameptr[0] == '.' &&
141 (cnp->cn_nameptr[1] == '.' || cnp->cn_nameptr[1] == '\0'))
142 return (1);
143 return (0);
144 }
145
146 /*
147 * Vnode op for reading directories.
148 */
149 int
ext2_readdir(struct vop_readdir_args * ap)150 ext2_readdir(struct vop_readdir_args *ap)
151 {
152 struct vnode *vp = ap->a_vp;
153 struct uio *uio = ap->a_uio;
154 struct buf *bp;
155 struct inode *ip;
156 struct ext2fs_direct_2 *dp, *edp;
157 u_long *cookies;
158 struct dirent dstdp;
159 off_t offset, startoffset;
160 size_t readcnt, skipcnt;
161 ssize_t startresid;
162 u_int ncookies;
163 int DIRBLKSIZ = VTOI(ap->a_vp)->i_e2fs->e2fs_bsize;
164 int error;
165
166 if (uio->uio_offset < 0)
167 return (EINVAL);
168 ip = VTOI(vp);
169 if (ap->a_ncookies != NULL) {
170 if (uio->uio_resid < 0)
171 ncookies = 0;
172 else
173 ncookies = uio->uio_resid;
174 if (uio->uio_offset >= ip->i_size)
175 ncookies = 0;
176 else if (ip->i_size - uio->uio_offset < ncookies)
177 ncookies = ip->i_size - uio->uio_offset;
178 ncookies = ncookies / (offsetof(struct ext2fs_direct_2,
179 e2d_namlen) + 4) + 1;
180 cookies = malloc(ncookies * sizeof(*cookies), M_TEMP, M_WAITOK);
181 *ap->a_ncookies = ncookies;
182 *ap->a_cookies = cookies;
183 } else {
184 ncookies = 0;
185 cookies = NULL;
186 }
187 offset = startoffset = uio->uio_offset;
188 startresid = uio->uio_resid;
189 error = 0;
190 while (error == 0 && uio->uio_resid > 0 &&
191 uio->uio_offset < ip->i_size) {
192 error = ext2_blkatoff(vp, uio->uio_offset, NULL, &bp);
193 if (error)
194 break;
195 if (bp->b_offset + bp->b_bcount > ip->i_size)
196 readcnt = ip->i_size - bp->b_offset;
197 else
198 readcnt = bp->b_bcount;
199 skipcnt = (size_t)(uio->uio_offset - bp->b_offset) &
200 ~(size_t)(DIRBLKSIZ - 1);
201 offset = bp->b_offset + skipcnt;
202 dp = (struct ext2fs_direct_2 *)&bp->b_data[skipcnt];
203 edp = (struct ext2fs_direct_2 *)&bp->b_data[readcnt];
204 while (error == 0 && uio->uio_resid > 0 && dp < edp) {
205 if (le16toh(dp->e2d_reclen) <= offsetof(struct ext2fs_direct_2,
206 e2d_namlen) || (caddr_t)dp + le16toh(dp->e2d_reclen) >
207 (caddr_t)edp) {
208 error = EIO;
209 break;
210 }
211 /*-
212 * "New" ext2fs directory entries differ in 3 ways
213 * from ufs on-disk ones:
214 * - the name is not necessarily NUL-terminated.
215 * - the file type field always exists and always
216 * follows the name length field.
217 * - the file type is encoded in a different way.
218 *
219 * "Old" ext2fs directory entries need no special
220 * conversions, since they are binary compatible
221 * with "new" entries having a file type of 0 (i.e.,
222 * EXT2_FT_UNKNOWN). Splitting the old name length
223 * field didn't make a mess like it did in ufs,
224 * because ext2fs uses a machine-independent disk
225 * layout.
226 */
227 dstdp.d_namlen = dp->e2d_namlen;
228 dstdp.d_type = FTTODT(dp->e2d_type);
229 if (offsetof(struct ext2fs_direct_2, e2d_namlen) +
230 dstdp.d_namlen > le16toh(dp->e2d_reclen)) {
231 error = EIO;
232 break;
233 }
234 if (offset < startoffset || le32toh(dp->e2d_ino) == 0)
235 goto nextentry;
236 dstdp.d_fileno = le32toh(dp->e2d_ino);
237 dstdp.d_reclen = GENERIC_DIRSIZ(&dstdp);
238 bcopy(dp->e2d_name, dstdp.d_name, dstdp.d_namlen);
239 /* NOTE: d_off is the offset of the *next* entry. */
240 dstdp.d_off = offset + le16toh(dp->e2d_reclen);
241 dirent_terminate(&dstdp);
242 if (dstdp.d_reclen > uio->uio_resid) {
243 if (uio->uio_resid == startresid)
244 error = EINVAL;
245 else
246 error = EJUSTRETURN;
247 break;
248 }
249 /* Advance dp. */
250 error = uiomove((caddr_t)&dstdp, dstdp.d_reclen, uio);
251 if (error)
252 break;
253 if (cookies != NULL) {
254 KASSERT(ncookies > 0,
255 ("ext2_readdir: cookies buffer too small"));
256 *cookies = offset + le16toh(dp->e2d_reclen);
257 cookies++;
258 ncookies--;
259 }
260 nextentry:
261 offset += le16toh(dp->e2d_reclen);
262 dp = (struct ext2fs_direct_2 *)((caddr_t)dp +
263 le16toh(dp->e2d_reclen));
264 }
265 bqrelse(bp);
266 uio->uio_offset = offset;
267 }
268 /* We need to correct uio_offset. */
269 uio->uio_offset = offset;
270 if (error == EJUSTRETURN)
271 error = 0;
272 if (ap->a_ncookies != NULL) {
273 if (error == 0) {
274 *ap->a_ncookies -= ncookies;
275 } else {
276 free(*ap->a_cookies, M_TEMP);
277 *ap->a_ncookies = 0;
278 *ap->a_cookies = NULL;
279 }
280 }
281 if (error == 0 && ap->a_eofflag)
282 *ap->a_eofflag = ip->i_size <= uio->uio_offset;
283 return (error);
284 }
285
286 /*
287 * Convert a component of a pathname into a pointer to a locked inode.
288 * This is a very central and rather complicated routine.
289 * If the file system is not maintained in a strict tree hierarchy,
290 * this can result in a deadlock situation (see comments in code below).
291 *
292 * The cnp->cn_nameiop argument is LOOKUP, CREATE, RENAME, or DELETE depending
293 * on whether the name is to be looked up, created, renamed, or deleted.
294 * When CREATE, RENAME, or DELETE is specified, information usable in
295 * creating, renaming, or deleting a directory entry may be calculated.
296 * If flag has LOCKPARENT or'ed into it and the target of the pathname
297 * exists, lookup returns both the target and its parent directory locked.
298 * When creating or renaming and LOCKPARENT is specified, the target may
299 * not be ".". When deleting and LOCKPARENT is specified, the target may
300 * be "."., but the caller must check to ensure it does an vrele and vput
301 * instead of two vputs.
302 *
303 * Overall outline of ext2_lookup:
304 *
305 * search for name in directory, to found or notfound
306 * notfound:
307 * if creating, return locked directory, leaving info on available slots
308 * else return error
309 * found:
310 * if at end of path and deleting, return information to allow delete
311 * if at end of path and rewriting (RENAME and LOCKPARENT), lock target
312 * inode and return info to allow rewrite
313 * if not at end, add name to cache; if at end and neither creating
314 * nor deleting, add name to cache
315 */
316 int
ext2_lookup(struct vop_cachedlookup_args * ap)317 ext2_lookup(struct vop_cachedlookup_args *ap)
318 {
319
320 return (ext2_lookup_ino(ap->a_dvp, ap->a_vpp, ap->a_cnp, NULL));
321 }
322
323 static int
ext2_lookup_ino(struct vnode * vdp,struct vnode ** vpp,struct componentname * cnp,ino_t * dd_ino)324 ext2_lookup_ino(struct vnode *vdp, struct vnode **vpp, struct componentname *cnp,
325 ino_t *dd_ino)
326 {
327 struct inode *dp; /* inode for directory being searched */
328 struct buf *bp; /* a buffer of directory entries */
329 struct ext2fs_direct_2 *ep; /* the current directory entry */
330 int entryoffsetinblock; /* offset of ep in bp's buffer */
331 struct ext2fs_searchslot ss;
332 doff_t i_diroff; /* cached i_diroff value */
333 doff_t i_offset; /* cached i_offset value */
334 int numdirpasses; /* strategy for directory search */
335 doff_t endsearch; /* offset to end directory search */
336 doff_t prevoff; /* prev entry dp->i_offset */
337 struct vnode *pdp; /* saved dp during symlink work */
338 struct vnode *tdp; /* returned by VFS_VGET */
339 doff_t enduseful; /* pointer past last used dir slot */
340 u_long bmask; /* block offset mask */
341 int error;
342 struct ucred *cred = cnp->cn_cred;
343 int flags = cnp->cn_flags;
344 int nameiop = cnp->cn_nameiop;
345 ino_t ino, ino1;
346 int ltype;
347 int entry_found = 0;
348
349 int DIRBLKSIZ = VTOI(vdp)->i_e2fs->e2fs_bsize;
350
351 if (vpp != NULL)
352 *vpp = NULL;
353
354 dp = VTOI(vdp);
355 bmask = VFSTOEXT2(vdp->v_mount)->um_mountp->mnt_stat.f_iosize - 1;
356 restart:
357 bp = NULL;
358 ss.slotoffset = -1;
359
360 /*
361 * We now have a segment name to search for, and a directory to search.
362 *
363 * Suppress search for slots unless creating
364 * file and at end of pathname, in which case
365 * we watch for a place to put the new file in
366 * case it doesn't already exist.
367 */
368 i_diroff = dp->i_diroff;
369 ss.slotstatus = FOUND;
370 ss.slotfreespace = ss.slotsize = ss.slotneeded = 0;
371 if ((nameiop == CREATE || nameiop == RENAME) &&
372 (flags & ISLASTCN)) {
373 ss.slotstatus = NONE;
374 ss.slotneeded = EXT2_DIR_REC_LEN(cnp->cn_namelen);
375 /*
376 * was ss.slotneeded = (sizeof(struct direct) - MAXNAMLEN +
377 * cnp->cn_namelen + 3) &~ 3;
378 */
379 }
380 /*
381 * Try to lookup dir entry using htree directory index.
382 *
383 * If we got an error or we want to find '.' or '..' entry,
384 * we will fall back to linear search.
385 */
386 if (!ext2_is_dot_entry(cnp) && ext2_htree_has_idx(dp)) {
387 numdirpasses = 1;
388 entryoffsetinblock = 0;
389 switch (ext2_htree_lookup(dp, cnp->cn_nameptr, cnp->cn_namelen,
390 &bp, &entryoffsetinblock, &i_offset, &prevoff,
391 &enduseful, &ss)) {
392 case 0:
393 ep = (struct ext2fs_direct_2 *)((char *)bp->b_data +
394 (i_offset & bmask));
395 goto foundentry;
396 case ENOENT:
397 i_offset = roundup2(dp->i_size, DIRBLKSIZ);
398 goto notfound;
399 default:
400 /*
401 * Something failed; just fallback to do a linear
402 * search.
403 */
404 break;
405 }
406 }
407
408 /*
409 * If there is cached information on a previous search of
410 * this directory, pick up where we last left off.
411 * We cache only lookups as these are the most common
412 * and have the greatest payoff. Caching CREATE has little
413 * benefit as it usually must search the entire directory
414 * to determine that the entry does not exist. Caching the
415 * location of the last DELETE or RENAME has not reduced
416 * profiling time and hence has been removed in the interest
417 * of simplicity.
418 */
419 if (nameiop != LOOKUP || i_diroff == 0 ||
420 i_diroff > dp->i_size) {
421 entryoffsetinblock = 0;
422 i_offset = 0;
423 numdirpasses = 1;
424 } else {
425 i_offset = i_diroff;
426 if ((entryoffsetinblock = i_offset & bmask) &&
427 (error = ext2_blkatoff(vdp, (off_t)i_offset, NULL,
428 &bp)))
429 return (error);
430 numdirpasses = 2;
431 nchstats.ncs_2passes++;
432 }
433 prevoff = i_offset;
434 endsearch = roundup2(dp->i_size, DIRBLKSIZ);
435 enduseful = 0;
436
437 searchloop:
438 while (i_offset < endsearch) {
439 /*
440 * If necessary, get the next directory block.
441 */
442 if (bp != NULL)
443 brelse(bp);
444 error = ext2_blkatoff(vdp, (off_t)i_offset, NULL, &bp);
445 if (error != 0)
446 return (error);
447
448 entryoffsetinblock = 0;
449 if (ss.slotstatus == NONE) {
450 ss.slotoffset = -1;
451 ss.slotfreespace = 0;
452 }
453
454 error = ext2_search_dirblock(dp, bp->b_data, &entry_found,
455 cnp->cn_nameptr, cnp->cn_namelen,
456 &entryoffsetinblock, &i_offset, &prevoff,
457 &enduseful, &ss);
458 if (error != 0) {
459 brelse(bp);
460 return (error);
461 }
462 if (entry_found) {
463 ep = (struct ext2fs_direct_2 *)((char *)bp->b_data +
464 (entryoffsetinblock & bmask));
465 foundentry:
466 ino = le32toh(ep->e2d_ino);
467 goto found;
468 }
469 }
470 notfound:
471 /*
472 * If we started in the middle of the directory and failed
473 * to find our target, we must check the beginning as well.
474 */
475 if (numdirpasses == 2) {
476 numdirpasses--;
477 i_offset = 0;
478 endsearch = i_diroff;
479 goto searchloop;
480 }
481 if (bp != NULL)
482 brelse(bp);
483 /*
484 * If creating, and at end of pathname and current
485 * directory has not been removed, then can consider
486 * allowing file to be created.
487 */
488 if ((nameiop == CREATE || nameiop == RENAME) &&
489 (flags & ISLASTCN) && dp->i_nlink != 0) {
490 /*
491 * Access for write is interpreted as allowing
492 * creation of files in the directory.
493 */
494 if ((error = VOP_ACCESS(vdp, VWRITE, cred, cnp->cn_thread)) != 0)
495 return (error);
496 /*
497 * Return an indication of where the new directory
498 * entry should be put. If we didn't find a slot,
499 * then set dp->i_count to 0 indicating
500 * that the new slot belongs at the end of the
501 * directory. If we found a slot, then the new entry
502 * can be put in the range from dp->i_offset to
503 * dp->i_offset + dp->i_count.
504 */
505 if (ss.slotstatus == NONE) {
506 dp->i_offset = roundup2(dp->i_size, DIRBLKSIZ);
507 dp->i_count = 0;
508 enduseful = dp->i_offset;
509 } else {
510 dp->i_offset = ss.slotoffset;
511 dp->i_count = ss.slotsize;
512 if (enduseful < ss.slotoffset + ss.slotsize)
513 enduseful = ss.slotoffset + ss.slotsize;
514 }
515 dp->i_endoff = roundup2(enduseful, DIRBLKSIZ);
516 /*
517 * We return with the directory locked, so that
518 * the parameters we set up above will still be
519 * valid if we actually decide to do a direnter().
520 * We return ni_vp == NULL to indicate that the entry
521 * does not currently exist; we leave a pointer to
522 * the (locked) directory inode in ndp->ni_dvp.
523 * The pathname buffer is saved so that the name
524 * can be obtained later.
525 *
526 * NB - if the directory is unlocked, then this
527 * information cannot be used.
528 */
529 cnp->cn_flags |= SAVENAME;
530 return (EJUSTRETURN);
531 }
532 /*
533 * Insert name into cache (as non-existent) if appropriate.
534 */
535 if ((cnp->cn_flags & MAKEENTRY) != 0)
536 cache_enter(vdp, NULL, cnp);
537 return (ENOENT);
538
539 found:
540 if (dd_ino != NULL)
541 *dd_ino = ino;
542 if (numdirpasses == 2)
543 nchstats.ncs_pass2++;
544 /*
545 * Check that directory length properly reflects presence
546 * of this entry.
547 */
548 if (entryoffsetinblock + EXT2_DIR_REC_LEN(ep->e2d_namlen) >
549 dp->i_size) {
550 ext2_dirbad(dp, i_offset, "i_size too small");
551 dp->i_size = entryoffsetinblock + EXT2_DIR_REC_LEN(ep->e2d_namlen);
552 dp->i_flag |= IN_CHANGE | IN_UPDATE;
553 }
554 brelse(bp);
555
556 /*
557 * Found component in pathname.
558 * If the final component of path name, save information
559 * in the cache as to where the entry was found.
560 */
561 if ((flags & ISLASTCN) && nameiop == LOOKUP)
562 dp->i_diroff = rounddown2(i_offset, DIRBLKSIZ);
563 /*
564 * If deleting, and at end of pathname, return
565 * parameters which can be used to remove file.
566 */
567 if (nameiop == DELETE && (flags & ISLASTCN)) {
568 if (flags & LOCKPARENT)
569 ASSERT_VOP_ELOCKED(vdp, __FUNCTION__);
570 /*
571 * Write access to directory required to delete files.
572 */
573 if ((error = VOP_ACCESS(vdp, VWRITE, cred, cnp->cn_thread)) != 0)
574 return (error);
575 /*
576 * Return pointer to current entry in dp->i_offset,
577 * and distance past previous entry (if there
578 * is a previous entry in this block) in dp->i_count.
579 * Save directory inode pointer in ndp->ni_dvp for dirremove().
580 *
581 * Technically we shouldn't be setting these in the
582 * WANTPARENT case (first lookup in rename()), but any
583 * lookups that will result in directory changes will
584 * overwrite these.
585 */
586 dp->i_offset = i_offset;
587 if ((dp->i_offset & (DIRBLKSIZ - 1)) == 0)
588 dp->i_count = 0;
589 else
590 dp->i_count = dp->i_offset - prevoff;
591 if (dd_ino != NULL)
592 return (0);
593 if (dp->i_number == ino) {
594 VREF(vdp);
595 *vpp = vdp;
596 return (0);
597 }
598 if ((error = VFS_VGET(vdp->v_mount, ino, LK_EXCLUSIVE,
599 &tdp)) != 0)
600 return (error);
601 /*
602 * If directory is "sticky", then user must own
603 * the directory, or the file in it, else she
604 * may not delete it (unless she's root). This
605 * implements append-only directories.
606 */
607 if ((dp->i_mode & ISVTX) &&
608 cred->cr_uid != 0 &&
609 cred->cr_uid != dp->i_uid &&
610 VTOI(tdp)->i_uid != cred->cr_uid) {
611 vput(tdp);
612 return (EPERM);
613 }
614 *vpp = tdp;
615 return (0);
616 }
617
618 /*
619 * If rewriting (RENAME), return the inode and the
620 * information required to rewrite the present directory
621 * Must get inode of directory entry to verify it's a
622 * regular file, or empty directory.
623 */
624 if (nameiop == RENAME && (flags & ISLASTCN)) {
625 if ((error = VOP_ACCESS(vdp, VWRITE, cred, cnp->cn_thread)) != 0)
626 return (error);
627 /*
628 * Careful about locking second inode.
629 * This can only occur if the target is ".".
630 */
631 dp->i_offset = i_offset;
632 if (dp->i_number == ino)
633 return (EISDIR);
634 if (dd_ino != NULL)
635 return (0);
636 if ((error = VFS_VGET(vdp->v_mount, ino, LK_EXCLUSIVE,
637 &tdp)) != 0)
638 return (error);
639 *vpp = tdp;
640 cnp->cn_flags |= SAVENAME;
641 return (0);
642 }
643 if (dd_ino != NULL)
644 return (0);
645
646 /*
647 * Step through the translation in the name. We do not `vput' the
648 * directory because we may need it again if a symbolic link
649 * is relative to the current directory. Instead we save it
650 * unlocked as "pdp". We must get the target inode before unlocking
651 * the directory to insure that the inode will not be removed
652 * before we get it. We prevent deadlock by always fetching
653 * inodes from the root, moving down the directory tree. Thus
654 * when following backward pointers ".." we must unlock the
655 * parent directory before getting the requested directory.
656 * There is a potential race condition here if both the current
657 * and parent directories are removed before the VFS_VGET for the
658 * inode associated with ".." returns. We hope that this occurs
659 * infrequently since we cannot avoid this race condition without
660 * implementing a sophisticated deadlock detection algorithm.
661 * Note also that this simple deadlock detection scheme will not
662 * work if the file system has any hard links other than ".."
663 * that point backwards in the directory structure.
664 */
665 pdp = vdp;
666 if (flags & ISDOTDOT) {
667 error = vn_vget_ino(pdp, ino, cnp->cn_lkflags, &tdp);
668 if (VN_IS_DOOMED(pdp)) {
669 if (error == 0)
670 vput(tdp);
671 error = ENOENT;
672 }
673 if (error)
674 return (error);
675 /*
676 * Recheck that ".." entry in the vdp directory points
677 * to the inode we looked up before vdp lock was
678 * dropped.
679 */
680 error = ext2_lookup_ino(pdp, NULL, cnp, &ino1);
681 if (error) {
682 vput(tdp);
683 return (error);
684 }
685 if (ino1 != ino) {
686 vput(tdp);
687 goto restart;
688 }
689 *vpp = tdp;
690 } else if (dp->i_number == ino) {
691 VREF(vdp); /* we want ourself, ie "." */
692 /*
693 * When we lookup "." we still can be asked to lock it
694 * differently.
695 */
696 ltype = cnp->cn_lkflags & LK_TYPE_MASK;
697 if (ltype != VOP_ISLOCKED(vdp)) {
698 if (ltype == LK_EXCLUSIVE)
699 vn_lock(vdp, LK_UPGRADE | LK_RETRY);
700 else /* if (ltype == LK_SHARED) */
701 vn_lock(vdp, LK_DOWNGRADE | LK_RETRY);
702 }
703 *vpp = vdp;
704 } else {
705 if ((error = VFS_VGET(vdp->v_mount, ino, cnp->cn_lkflags,
706 &tdp)) != 0)
707 return (error);
708 *vpp = tdp;
709 }
710
711 /*
712 * Insert name into cache if appropriate.
713 */
714 if (cnp->cn_flags & MAKEENTRY)
715 cache_enter(vdp, *vpp, cnp);
716 return (0);
717 }
718
719 int
ext2_search_dirblock(struct inode * ip,void * data,int * foundp,const char * name,int namelen,int * entryoffsetinblockp,doff_t * offp,doff_t * prevoffp,doff_t * endusefulp,struct ext2fs_searchslot * ssp)720 ext2_search_dirblock(struct inode *ip, void *data, int *foundp,
721 const char *name, int namelen, int *entryoffsetinblockp,
722 doff_t *offp, doff_t *prevoffp, doff_t *endusefulp,
723 struct ext2fs_searchslot *ssp)
724 {
725 struct vnode *vdp;
726 struct ext2fs_direct_2 *ep, *top;
727 uint32_t bsize = ip->i_e2fs->e2fs_bsize;
728 int offset = *entryoffsetinblockp;
729 int namlen;
730
731 vdp = ITOV(ip);
732
733 ep = (struct ext2fs_direct_2 *)((char *)data + offset);
734 top = (struct ext2fs_direct_2 *)((char *)data + bsize);
735 while (ep < top) {
736 /*
737 * Full validation checks are slow, so we only check
738 * enough to insure forward progress through the
739 * directory. Complete checks can be run by setting
740 * "vfs.e2fs.dirchk" to be true.
741 */
742 if (le16toh(ep->e2d_reclen) == 0 ||
743 (dirchk && ext2_dirbadentry(vdp, ep, offset))) {
744 int i;
745
746 ext2_dirbad(ip, *offp, "mangled entry");
747 i = bsize - (offset & (bsize - 1));
748 *offp += i;
749 offset += i;
750 continue;
751 }
752
753 /*
754 * If an appropriate sized slot has not yet been found,
755 * check to see if one is available. Also accumulate space
756 * in the current block so that we can determine if
757 * compaction is viable.
758 */
759 if (ssp->slotstatus != FOUND) {
760 int size = le16toh(ep->e2d_reclen);
761
762 if (ep->e2d_ino != 0)
763 size -= EXT2_DIR_REC_LEN(ep->e2d_namlen);
764 else if (ext2_is_dirent_tail(ip, ep))
765 size -= sizeof(struct ext2fs_direct_tail);
766 if (size > 0) {
767 if (size >= ssp->slotneeded) {
768 ssp->slotstatus = FOUND;
769 ssp->slotoffset = *offp;
770 ssp->slotsize = le16toh(ep->e2d_reclen);
771 } else if (ssp->slotstatus == NONE) {
772 ssp->slotfreespace += size;
773 if (ssp->slotoffset == -1)
774 ssp->slotoffset = *offp;
775 if (ssp->slotfreespace >= ssp->slotneeded) {
776 ssp->slotstatus = COMPACT;
777 ssp->slotsize = *offp +
778 le16toh(ep->e2d_reclen) -
779 ssp->slotoffset;
780 }
781 }
782 }
783 }
784 /*
785 * Check for a name match.
786 */
787 if (ep->e2d_ino != 0) {
788 namlen = ep->e2d_namlen;
789 if (namlen == namelen &&
790 !bcmp(name, ep->e2d_name, (unsigned)namlen)) {
791 /*
792 * Save directory entry's inode number and
793 * reclen in ndp->ni_ufs area, and release
794 * directory buffer.
795 */
796 *foundp = 1;
797 return (0);
798 }
799 }
800 *prevoffp = *offp;
801 *offp += le16toh(ep->e2d_reclen);
802 offset += le16toh(ep->e2d_reclen);
803 *entryoffsetinblockp = offset;
804 if (ep->e2d_ino != 0)
805 *endusefulp = *offp;
806 /*
807 * Get pointer to the next entry.
808 */
809 ep = (struct ext2fs_direct_2 *)((char *)data + offset);
810 }
811
812 return (0);
813 }
814
815 void
ext2_dirbad(struct inode * ip,doff_t offset,char * how)816 ext2_dirbad(struct inode *ip, doff_t offset, char *how)
817 {
818 struct mount *mp;
819
820 mp = ITOV(ip)->v_mount;
821 if ((mp->mnt_flag & MNT_RDONLY) == 0)
822 panic("ext2_dirbad: %s: bad dir ino %ju at offset %ld: %s\n",
823 mp->mnt_stat.f_mntonname, (uintmax_t)ip->i_number,
824 (long)offset, how);
825 else
826 SDT_PROBE4(ext2fs, , trace, ext2_dirbad_error,
827 mp->mnt_stat.f_mntonname, ip->i_number, offset, how);
828 }
829
830 /*
831 * Do consistency checking on a directory entry:
832 * record length must be multiple of 4
833 * entry must fit in rest of its DIRBLKSIZ block
834 * record must be large enough to contain entry
835 * name is not longer than MAXNAMLEN
836 * name must be as long as advertised, and null terminated
837 */
838 /*
839 * changed so that it confirms to ext2_check_dir_entry
840 */
841 static int
ext2_dirbadentry(struct vnode * dp,struct ext2fs_direct_2 * de,int entryoffsetinblock)842 ext2_dirbadentry(struct vnode *dp, struct ext2fs_direct_2 *de,
843 int entryoffsetinblock)
844 {
845 int DIRBLKSIZ = VTOI(dp)->i_e2fs->e2fs_bsize;
846
847 char *error_msg = NULL;
848
849 if (le16toh(de->e2d_reclen) < EXT2_DIR_REC_LEN(1))
850 error_msg = "rec_len is smaller than minimal";
851 else if (le16toh(de->e2d_reclen) % 4 != 0)
852 error_msg = "rec_len % 4 != 0";
853 else if (le16toh(de->e2d_reclen) < EXT2_DIR_REC_LEN(de->e2d_namlen))
854 error_msg = "reclen is too small for name_len";
855 else if (entryoffsetinblock + le16toh(de->e2d_reclen)> DIRBLKSIZ)
856 error_msg = "directory entry across blocks";
857 /* else LATER
858 if (de->inode > dir->i_sb->u.ext2_sb.s_es->s_inodes_count)
859 error_msg = "inode out of bounds";
860 */
861
862 if (error_msg != NULL) {
863 SDT_PROBE5(ext2fs, , trace, ext2_dirbadentry_error,
864 error_msg, entryoffsetinblock,
865 le32toh(de->e2d_ino), le16toh(de->e2d_reclen),
866 de->e2d_namlen);
867 }
868 return (error_msg == NULL ? 0 : 1);
869 }
870
871 /*
872 * Insert an entry into the fresh directory block.
873 * Initialize entry tail if the metadata_csum feature is turned on.
874 */
875 static int
ext2_add_first_entry(struct vnode * dvp,struct ext2fs_direct_2 * entry,struct componentname * cnp)876 ext2_add_first_entry(struct vnode *dvp, struct ext2fs_direct_2 *entry,
877 struct componentname *cnp)
878 {
879 struct inode *dp;
880 struct iovec aiov;
881 struct uio auio;
882 char* buf = NULL;
883 int dirblksize, error;
884
885 dp = VTOI(dvp);
886 dirblksize = dp->i_e2fs->e2fs_bsize;
887
888 if (dp->i_offset & (dirblksize - 1))
889 panic("ext2_add_first_entry: bad directory offset");
890
891 if (EXT2_HAS_RO_COMPAT_FEATURE(dp->i_e2fs,
892 EXT2F_ROCOMPAT_METADATA_CKSUM)) {
893 entry->e2d_reclen = htole16(dirblksize -
894 sizeof(struct ext2fs_direct_tail));
895 buf = malloc(dirblksize, M_TEMP, M_WAITOK);
896 memcpy(buf, entry, EXT2_DIR_REC_LEN(entry->e2d_namlen));
897 ext2_init_dirent_tail(EXT2_DIRENT_TAIL(buf, dirblksize));
898 ext2_dirent_csum_set(dp, (struct ext2fs_direct_2 *)buf);
899
900 auio.uio_offset = dp->i_offset;
901 auio.uio_resid = dirblksize;
902 aiov.iov_len = auio.uio_resid;
903 aiov.iov_base = (caddr_t)buf;
904 } else {
905 entry->e2d_reclen = htole16(dirblksize);
906 auio.uio_offset = dp->i_offset;
907 auio.uio_resid = EXT2_DIR_REC_LEN(entry->e2d_namlen);
908 aiov.iov_len = auio.uio_resid;
909 aiov.iov_base = (caddr_t)entry;
910 }
911
912 auio.uio_iov = &aiov;
913 auio.uio_iovcnt = 1;
914 auio.uio_rw = UIO_WRITE;
915 auio.uio_segflg = UIO_SYSSPACE;
916 auio.uio_td = (struct thread *)0;
917 error = VOP_WRITE(dvp, &auio, IO_SYNC, cnp->cn_cred);
918 if (error)
919 goto out;
920
921 dp->i_size = roundup2(dp->i_size, dirblksize);
922 dp->i_flag |= IN_CHANGE;
923
924 out:
925 free(buf, M_TEMP);
926 return (error);
927
928 }
929
930 /*
931 * Write a directory entry after a call to namei, using the parameters
932 * that it left in nameidata. The argument ip is the inode which the new
933 * directory entry will refer to. Dvp is a pointer to the directory to
934 * be written, which was left locked by namei. Remaining parameters
935 * (dp->i_offset, dp->i_count) indicate how the space for the new
936 * entry is to be obtained.
937 */
938 int
ext2_direnter(struct inode * ip,struct vnode * dvp,struct componentname * cnp)939 ext2_direnter(struct inode *ip, struct vnode *dvp, struct componentname *cnp)
940 {
941 struct inode *dp;
942 struct ext2fs_direct_2 newdir;
943 int DIRBLKSIZ = ip->i_e2fs->e2fs_bsize;
944 int error;
945
946 #ifdef INVARIANTS
947 if ((cnp->cn_flags & SAVENAME) == 0)
948 panic("ext2_direnter: missing name");
949 #endif
950 dp = VTOI(dvp);
951 newdir.e2d_ino = htole32(ip->i_number);
952 if (EXT2_HAS_INCOMPAT_FEATURE(ip->i_e2fs,
953 EXT2F_INCOMPAT_FTYPE)) {
954 newdir.e2d_namlen = cnp->cn_namelen;
955 newdir.e2d_type = DTTOFT(IFTODT(ip->i_mode));
956 } else
957 newdir.e2d_namlen = htole16(cnp->cn_namelen);
958
959 bcopy(cnp->cn_nameptr, newdir.e2d_name, (unsigned)cnp->cn_namelen + 1);
960
961 if (ext2_htree_has_idx(dp)) {
962 error = ext2_htree_add_entry(dvp, &newdir, cnp);
963 if (error) {
964 dp->i_flag &= ~IN_E3INDEX;
965 dp->i_flag |= IN_CHANGE | IN_UPDATE;
966 }
967 return (error);
968 }
969
970 if (EXT2_HAS_COMPAT_FEATURE(ip->i_e2fs, EXT2F_COMPAT_DIRHASHINDEX) &&
971 !ext2_htree_has_idx(dp)) {
972 if ((dp->i_size / DIRBLKSIZ) == 1 &&
973 dp->i_offset == DIRBLKSIZ) {
974 /*
975 * Making indexed directory when one block is not
976 * enough to save all entries.
977 */
978 return ext2_htree_create_index(dvp, cnp, &newdir);
979 }
980 }
981
982 /*
983 * If dp->i_count is 0, then namei could find no
984 * space in the directory. Here, dp->i_offset will
985 * be on a directory block boundary and we will write the
986 * new entry into a fresh block.
987 */
988 if (dp->i_count == 0)
989 return ext2_add_first_entry(dvp, &newdir, cnp);
990
991 error = ext2_add_entry(dvp, &newdir);
992 if (!error && dp->i_endoff && dp->i_endoff < dp->i_size)
993 error = ext2_truncate(dvp, (off_t)dp->i_endoff, IO_SYNC,
994 cnp->cn_cred, cnp->cn_thread);
995 return (error);
996 }
997
998 /*
999 * Insert an entry into the directory block.
1000 * Compact the contents.
1001 */
1002 int
ext2_add_entry(struct vnode * dvp,struct ext2fs_direct_2 * entry)1003 ext2_add_entry(struct vnode *dvp, struct ext2fs_direct_2 *entry)
1004 {
1005 struct ext2fs_direct_2 *ep, *nep;
1006 struct inode *dp;
1007 struct buf *bp;
1008 u_int dsize;
1009 int error, loc, newentrysize, spacefree;
1010 char *dirbuf;
1011
1012 dp = VTOI(dvp);
1013
1014 /*
1015 * If dp->i_count is non-zero, then namei found space
1016 * for the new entry in the range dp->i_offset to
1017 * dp->i_offset + dp->i_count in the directory.
1018 * To use this space, we may have to compact the entries located
1019 * there, by copying them together towards the beginning of the
1020 * block, leaving the free space in one usable chunk at the end.
1021 */
1022
1023 /*
1024 * Increase size of directory if entry eats into new space.
1025 * This should never push the size past a new multiple of
1026 * DIRBLKSIZE.
1027 *
1028 * N.B. - THIS IS AN ARTIFACT OF 4.2 AND SHOULD NEVER HAPPEN.
1029 */
1030 if (dp->i_offset + dp->i_count > dp->i_size)
1031 dp->i_size = dp->i_offset + dp->i_count;
1032 /*
1033 * Get the block containing the space for the new directory entry.
1034 */
1035 if ((error = ext2_blkatoff(dvp, (off_t)dp->i_offset, &dirbuf,
1036 &bp)) != 0)
1037 return (error);
1038 /*
1039 * Find space for the new entry. In the simple case, the entry at
1040 * offset base will have the space. If it does not, then namei
1041 * arranged that compacting the region dp->i_offset to
1042 * dp->i_offset + dp->i_count would yield the
1043 * space.
1044 */
1045 newentrysize = EXT2_DIR_REC_LEN(entry->e2d_namlen);
1046 ep = (struct ext2fs_direct_2 *)dirbuf;
1047 dsize = EXT2_DIR_REC_LEN(ep->e2d_namlen);
1048 spacefree = le16toh(ep->e2d_reclen) - dsize;
1049 for (loc = le16toh(ep->e2d_reclen); loc < dp->i_count; ) {
1050 nep = (struct ext2fs_direct_2 *)(dirbuf + loc);
1051 if (le32toh(ep->e2d_ino)) {
1052 /* trim the existing slot */
1053 ep->e2d_reclen = htole16(dsize);
1054 ep = (struct ext2fs_direct_2 *)((char *)ep + dsize);
1055 } else {
1056 /* overwrite; nothing there; header is ours */
1057 spacefree += dsize;
1058 }
1059 dsize = EXT2_DIR_REC_LEN(nep->e2d_namlen);
1060 spacefree += le16toh(nep->e2d_reclen) - dsize;
1061 loc += le16toh(nep->e2d_reclen);
1062 bcopy((caddr_t)nep, (caddr_t)ep, dsize);
1063 }
1064 /*
1065 * Update the pointer fields in the previous entry (if any),
1066 * copy in the new entry, and write out the block.
1067 */
1068 if (ep->e2d_ino == 0) {
1069 if (spacefree + dsize < newentrysize)
1070 panic("ext2_direnter: compact1");
1071 entry->e2d_reclen = htole16(spacefree + dsize);
1072 } else {
1073 if (spacefree < newentrysize)
1074 panic("ext2_direnter: compact2");
1075 entry->e2d_reclen = htole16(spacefree);
1076 ep->e2d_reclen = htole16(dsize);
1077 ep = (struct ext2fs_direct_2 *)((char *)ep + dsize);
1078 }
1079 bcopy((caddr_t)entry, (caddr_t)ep, (u_int)newentrysize);
1080 ext2_dirent_csum_set(dp, (struct ext2fs_direct_2 *)bp->b_data);
1081 if (DOINGASYNC(dvp)) {
1082 bdwrite(bp);
1083 error = 0;
1084 } else {
1085 error = bwrite(bp);
1086 }
1087 dp->i_flag |= IN_CHANGE | IN_UPDATE;
1088 return (error);
1089 }
1090
1091 /*
1092 * Remove a directory entry after a call to namei, using
1093 * the parameters which it left in nameidata. The entry
1094 * dp->i_offset contains the offset into the directory of the
1095 * entry to be eliminated. The dp->i_count field contains the
1096 * size of the previous record in the directory. If this
1097 * is 0, the first entry is being deleted, so we need only
1098 * zero the inode number to mark the entry as free. If the
1099 * entry is not the first in the directory, we must reclaim
1100 * the space of the now empty record by adding the record size
1101 * to the size of the previous entry.
1102 */
1103 int
ext2_dirremove(struct vnode * dvp,struct componentname * cnp)1104 ext2_dirremove(struct vnode *dvp, struct componentname *cnp)
1105 {
1106 struct inode *dp;
1107 struct ext2fs_direct_2 *ep, *rep;
1108 struct buf *bp;
1109 int error;
1110
1111 dp = VTOI(dvp);
1112 if (dp->i_count == 0) {
1113 /*
1114 * First entry in block: set d_ino to zero.
1115 */
1116 if ((error =
1117 ext2_blkatoff(dvp, (off_t)dp->i_offset, (char **)&ep,
1118 &bp)) != 0)
1119 return (error);
1120 ep->e2d_ino = 0;
1121 ext2_dirent_csum_set(dp, (struct ext2fs_direct_2 *)bp->b_data);
1122 error = bwrite(bp);
1123 dp->i_flag |= IN_CHANGE | IN_UPDATE;
1124 return (error);
1125 }
1126 /*
1127 * Collapse new free space into previous entry.
1128 */
1129 if ((error = ext2_blkatoff(dvp, (off_t)(dp->i_offset - dp->i_count),
1130 (char **)&ep, &bp)) != 0)
1131 return (error);
1132
1133 /* Set 'rep' to the entry being removed. */
1134 if (dp->i_count == 0)
1135 rep = ep;
1136 else
1137 rep = (struct ext2fs_direct_2 *)((char *)ep +
1138 le16toh(ep->e2d_reclen));
1139 ep->e2d_reclen += rep->e2d_reclen;
1140 ext2_dirent_csum_set(dp, (struct ext2fs_direct_2 *)bp->b_data);
1141 if (DOINGASYNC(dvp) && dp->i_count != 0)
1142 bdwrite(bp);
1143 else
1144 error = bwrite(bp);
1145 dp->i_flag |= IN_CHANGE | IN_UPDATE;
1146 return (error);
1147 }
1148
1149 /*
1150 * Rewrite an existing directory entry to point at the inode
1151 * supplied. The parameters describing the directory entry are
1152 * set up by a call to namei.
1153 */
1154 int
ext2_dirrewrite(struct inode * dp,struct inode * ip,struct componentname * cnp)1155 ext2_dirrewrite(struct inode *dp, struct inode *ip, struct componentname *cnp)
1156 {
1157 struct buf *bp;
1158 struct ext2fs_direct_2 *ep;
1159 struct vnode *vdp = ITOV(dp);
1160 int error;
1161
1162 if ((error = ext2_blkatoff(vdp, (off_t)dp->i_offset, (char **)&ep,
1163 &bp)) != 0)
1164 return (error);
1165 ep->e2d_ino = htole32(ip->i_number);
1166 if (EXT2_HAS_INCOMPAT_FEATURE(ip->i_e2fs,
1167 EXT2F_INCOMPAT_FTYPE))
1168 ep->e2d_type = DTTOFT(IFTODT(ip->i_mode));
1169 else
1170 ep->e2d_type = EXT2_FT_UNKNOWN;
1171 ext2_dirent_csum_set(dp, (struct ext2fs_direct_2 *)bp->b_data);
1172 error = bwrite(bp);
1173 dp->i_flag |= IN_CHANGE | IN_UPDATE;
1174 return (error);
1175 }
1176
1177 /*
1178 * Check if a directory is empty or not.
1179 * Inode supplied must be locked.
1180 *
1181 * Using a struct dirtemplate here is not precisely
1182 * what we want, but better than using a struct direct.
1183 *
1184 * NB: does not handle corrupted directories.
1185 */
1186 int
ext2_dirempty(struct inode * ip,ino_t parentino,struct ucred * cred)1187 ext2_dirempty(struct inode *ip, ino_t parentino, struct ucred *cred)
1188 {
1189 off_t off;
1190 struct dirtemplate dbuf;
1191 struct ext2fs_direct_2 *dp = (struct ext2fs_direct_2 *)&dbuf;
1192 int error, namlen;
1193 ssize_t count;
1194 #define MINDIRSIZ (sizeof(struct dirtemplate) / 2)
1195
1196 for (off = 0; off < ip->i_size; off += le16toh(dp->e2d_reclen)) {
1197 error = vn_rdwr(UIO_READ, ITOV(ip), (caddr_t)dp, MINDIRSIZ,
1198 off, UIO_SYSSPACE, IO_NODELOCKED | IO_NOMACCHECK, cred,
1199 NOCRED, &count, (struct thread *)0);
1200 /*
1201 * Since we read MINDIRSIZ, residual must
1202 * be 0 unless we're at end of file.
1203 */
1204 if (error || count != 0)
1205 return (0);
1206 /* avoid infinite loops */
1207 if (dp->e2d_reclen == 0)
1208 return (0);
1209 /* skip empty entries */
1210 if (dp->e2d_ino == 0)
1211 continue;
1212 /* accept only "." and ".." */
1213 namlen = dp->e2d_namlen;
1214 if (namlen > 2)
1215 return (0);
1216 if (dp->e2d_name[0] != '.')
1217 return (0);
1218 /*
1219 * At this point namlen must be 1 or 2.
1220 * 1 implies ".", 2 implies ".." if second
1221 * char is also "."
1222 */
1223 if (namlen == 1)
1224 continue;
1225 if (dp->e2d_name[1] == '.' && le32toh(dp->e2d_ino) == parentino)
1226 continue;
1227 return (0);
1228 }
1229 return (1);
1230 }
1231
1232 /*
1233 * Check if source directory is in the path of the target directory.
1234 * Target is supplied locked, source is unlocked.
1235 * The target is always vput before returning.
1236 */
1237 int
ext2_checkpath(struct inode * source,struct inode * target,struct ucred * cred)1238 ext2_checkpath(struct inode *source, struct inode *target, struct ucred *cred)
1239 {
1240 struct vnode *vp;
1241 int error, namlen;
1242 struct dirtemplate dirbuf;
1243
1244 vp = ITOV(target);
1245 if (target->i_number == source->i_number) {
1246 error = EEXIST;
1247 goto out;
1248 }
1249 if (target->i_number == EXT2_ROOTINO) {
1250 error = 0;
1251 goto out;
1252 }
1253
1254 for (;;) {
1255 if (vp->v_type != VDIR) {
1256 error = ENOTDIR;
1257 break;
1258 }
1259 error = vn_rdwr(UIO_READ, vp, (caddr_t)&dirbuf,
1260 sizeof(struct dirtemplate), (off_t)0, UIO_SYSSPACE,
1261 IO_NODELOCKED | IO_NOMACCHECK, cred, NOCRED, NULL,
1262 NULL);
1263 if (error != 0)
1264 break;
1265 namlen = dirbuf.dotdot_type; /* like ufs little-endian */
1266 if (namlen != 2 ||
1267 dirbuf.dotdot_name[0] != '.' ||
1268 dirbuf.dotdot_name[1] != '.') {
1269 error = ENOTDIR;
1270 break;
1271 }
1272 if (le32toh(dirbuf.dotdot_ino) == source->i_number) {
1273 error = EINVAL;
1274 break;
1275 }
1276 if (le32toh(dirbuf.dotdot_ino) == EXT2_ROOTINO)
1277 break;
1278 vput(vp);
1279 if ((error = VFS_VGET(vp->v_mount, le32toh(dirbuf.dotdot_ino),
1280 LK_EXCLUSIVE, &vp)) != 0) {
1281 vp = NULL;
1282 break;
1283 }
1284 }
1285
1286 out:
1287 if (error == ENOTDIR)
1288 SDT_PROBE2(ext2fs, , lookup, trace, 1,
1289 "checkpath: .. not a directory");
1290 if (vp != NULL)
1291 vput(vp);
1292 return (error);
1293 }
1294