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: releng/11.1/sys/fs/ext2fs/ext2_lookup.c 311231 2017-01-04 02:42:17Z pfg $
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 ncookies = uio->uio_resid;
154 if (uio->uio_offset >= ip->i_size)
155 ncookies = 0;
156 else if (ip->i_size - uio->uio_offset < ncookies)
157 ncookies = ip->i_size - uio->uio_offset;
158 ncookies = ncookies / (offsetof(struct ext2fs_direct_2,
159 e2d_namlen) + 4) + 1;
160 cookies = malloc(ncookies * sizeof(*cookies), M_TEMP, M_WAITOK);
161 *ap->a_ncookies = ncookies;
162 *ap->a_cookies = cookies;
163 } else {
164 ncookies = 0;
165 cookies = NULL;
166 }
167 offset = startoffset = uio->uio_offset;
168 startresid = uio->uio_resid;
169 error = 0;
170 while (error == 0 && uio->uio_resid > 0 &&
171 uio->uio_offset < ip->i_size) {
172 error = ext2_blkatoff(vp, uio->uio_offset, NULL, &bp);
173 if (error)
174 break;
175 if (bp->b_offset + bp->b_bcount > ip->i_size)
176 readcnt = ip->i_size - bp->b_offset;
177 else
178 readcnt = bp->b_bcount;
179 skipcnt = (size_t)(uio->uio_offset - bp->b_offset) &
180 ~(size_t)(DIRBLKSIZ - 1);
181 offset = bp->b_offset + skipcnt;
182 dp = (struct ext2fs_direct_2 *)&bp->b_data[skipcnt];
183 edp = (struct ext2fs_direct_2 *)&bp->b_data[readcnt];
184 while (error == 0 && uio->uio_resid > 0 && dp < edp) {
185 if (dp->e2d_reclen <= offsetof(struct ext2fs_direct_2,
186 e2d_namlen) || (caddr_t)dp + dp->e2d_reclen >
187 (caddr_t)edp) {
188 error = EIO;
189 break;
190 }
191 /*-
192 * "New" ext2fs directory entries differ in 3 ways
193 * from ufs on-disk ones:
194 * - the name is not necessarily NUL-terminated.
195 * - the file type field always exists and always
196 * follows the name length field.
197 * - the file type is encoded in a different way.
198 *
199 * "Old" ext2fs directory entries need no special
200 * conversions, since they are binary compatible
201 * with "new" entries having a file type of 0 (i.e.,
202 * EXT2_FT_UNKNOWN). Splitting the old name length
203 * field didn't make a mess like it did in ufs,
204 * because ext2fs uses a machine-independent disk
205 * layout.
206 */
207 dstdp.d_namlen = dp->e2d_namlen;
208 dstdp.d_type = FTTODT(dp->e2d_type);
209 if (offsetof(struct ext2fs_direct_2, e2d_namlen) +
210 dstdp.d_namlen > dp->e2d_reclen) {
211 error = EIO;
212 break;
213 }
214 if (offset < startoffset || dp->e2d_ino == 0)
215 goto nextentry;
216 dstdp.d_fileno = dp->e2d_ino;
217 dstdp.d_reclen = GENERIC_DIRSIZ(&dstdp);
218 bcopy(dp->e2d_name, dstdp.d_name, dstdp.d_namlen);
219 dstdp.d_name[dstdp.d_namlen] = '\0';
220 if (dstdp.d_reclen > uio->uio_resid) {
221 if (uio->uio_resid == startresid)
222 error = EINVAL;
223 else
224 error = EJUSTRETURN;
225 break;
226 }
227 /* Advance dp. */
228 error = uiomove((caddr_t)&dstdp, dstdp.d_reclen, uio);
229 if (error)
230 break;
231 if (cookies != NULL) {
232 KASSERT(ncookies > 0,
233 ("ext2_readdir: cookies buffer too small"));
234 *cookies = offset + dp->e2d_reclen;
235 cookies++;
236 ncookies--;
237 }
238 nextentry:
239 offset += dp->e2d_reclen;
240 dp = (struct ext2fs_direct_2 *)((caddr_t)dp +
241 dp->e2d_reclen);
242 }
243 bqrelse(bp);
244 uio->uio_offset = offset;
245 }
246 /* We need to correct uio_offset. */
247 uio->uio_offset = offset;
248 if (error == EJUSTRETURN)
249 error = 0;
250 if (ap->a_ncookies != NULL) {
251 if (error == 0) {
252 ap->a_ncookies -= ncookies;
253 } else {
254 free(*ap->a_cookies, M_TEMP);
255 *ap->a_ncookies = 0;
256 *ap->a_cookies = NULL;
257 }
258 }
259 if (error == 0 && ap->a_eofflag)
260 *ap->a_eofflag = ip->i_size <= uio->uio_offset;
261 return (error);
262 }
263
264 /*
265 * Convert a component of a pathname into a pointer to a locked inode.
266 * This is a very central and rather complicated routine.
267 * If the file system is not maintained in a strict tree hierarchy,
268 * this can result in a deadlock situation (see comments in code below).
269 *
270 * The cnp->cn_nameiop argument is LOOKUP, CREATE, RENAME, or DELETE depending
271 * on whether the name is to be looked up, created, renamed, or deleted.
272 * When CREATE, RENAME, or DELETE is specified, information usable in
273 * creating, renaming, or deleting a directory entry may be calculated.
274 * If flag has LOCKPARENT or'ed into it and the target of the pathname
275 * exists, lookup returns both the target and its parent directory locked.
276 * When creating or renaming and LOCKPARENT is specified, the target may
277 * not be ".". When deleting and LOCKPARENT is specified, the target may
278 * be "."., but the caller must check to ensure it does an vrele and vput
279 * instead of two vputs.
280 *
281 * Overall outline of ext2_lookup:
282 *
283 * search for name in directory, to found or notfound
284 * notfound:
285 * if creating, return locked directory, leaving info on available slots
286 * else return error
287 * found:
288 * if at end of path and deleting, return information to allow delete
289 * if at end of path and rewriting (RENAME and LOCKPARENT), lock target
290 * inode and return info to allow rewrite
291 * if not at end, add name to cache; if at end and neither creating
292 * nor deleting, add name to cache
293 */
294 int
295 ext2_lookup(struct vop_cachedlookup_args *ap)
296 {
297
298 return (ext2_lookup_ino(ap->a_dvp, ap->a_vpp, ap->a_cnp, NULL));
299 }
300
301 static int
302 ext2_lookup_ino(struct vnode *vdp, struct vnode **vpp, struct componentname *cnp,
303 ino_t *dd_ino)
304 {
305 struct inode *dp; /* inode for directory being searched */
306 struct buf *bp; /* a buffer of directory entries */
307 struct ext2fs_direct_2 *ep; /* the current directory entry */
308 int entryoffsetinblock; /* offset of ep in bp's buffer */
309 struct ext2fs_searchslot ss;
310 doff_t i_diroff; /* cached i_diroff value */
311 doff_t i_offset; /* cached i_offset value */
312 int numdirpasses; /* strategy for directory search */
313 doff_t endsearch; /* offset to end directory search */
314 doff_t prevoff; /* prev entry dp->i_offset */
315 struct vnode *pdp; /* saved dp during symlink work */
316 struct vnode *tdp; /* returned by VFS_VGET */
317 doff_t enduseful; /* pointer past last used dir slot */
318 u_long bmask; /* block offset mask */
319 int error;
320 struct ucred *cred = cnp->cn_cred;
321 int flags = cnp->cn_flags;
322 int nameiop = cnp->cn_nameiop;
323 ino_t ino, ino1;
324 int ltype;
325 int entry_found = 0;
326
327 int DIRBLKSIZ = VTOI(vdp)->i_e2fs->e2fs_bsize;
328
329 if (vpp != NULL)
330 *vpp = NULL;
331
332 dp = VTOI(vdp);
333 bmask = VFSTOEXT2(vdp->v_mount)->um_mountp->mnt_stat.f_iosize - 1;
334 restart:
335 bp = NULL;
336 ss.slotoffset = -1;
337
338 /*
339 * We now have a segment name to search for, and a directory to search.
340 *
341 * Suppress search for slots unless creating
342 * file and at end of pathname, in which case
343 * we watch for a place to put the new file in
344 * case it doesn't already exist.
345 */
346 i_diroff = dp->i_diroff;
347 ss.slotstatus = FOUND;
348 ss.slotfreespace = ss.slotsize = ss.slotneeded = 0;
349 if ((nameiop == CREATE || nameiop == RENAME) &&
350 (flags & ISLASTCN)) {
351 ss.slotstatus = NONE;
352 ss.slotneeded = EXT2_DIR_REC_LEN(cnp->cn_namelen);
353 /*
354 * was ss.slotneeded = (sizeof(struct direct) - MAXNAMLEN +
355 * cnp->cn_namelen + 3) &~ 3;
356 */
357 }
358 /*
359 * Try to lookup dir entry using htree directory index.
360 *
361 * If we got an error or we want to find '.' or '..' entry,
362 * we will fall back to linear search.
363 */
364 if (!ext2_is_dot_entry(cnp) && ext2_htree_has_idx(dp)) {
365 numdirpasses = 1;
366 entryoffsetinblock = 0;
367 switch (ext2_htree_lookup(dp, cnp->cn_nameptr, cnp->cn_namelen,
368 &bp, &entryoffsetinblock, &i_offset, &prevoff,
369 &enduseful, &ss)) {
370 case 0:
371 ep = (struct ext2fs_direct_2 *)((char *)bp->b_data +
372 (i_offset & bmask));
373 goto foundentry;
374 case ENOENT:
375 i_offset = roundup2(dp->i_size, DIRBLKSIZ);
376 goto notfound;
377 default:
378 /*
379 * Something failed; just fallback to do a linear
380 * search.
381 */
382 break;
383 }
384 }
385
386 /*
387 * If there is cached information on a previous search of
388 * this directory, pick up where we last left off.
389 * We cache only lookups as these are the most common
390 * and have the greatest payoff. Caching CREATE has little
391 * benefit as it usually must search the entire directory
392 * to determine that the entry does not exist. Caching the
393 * location of the last DELETE or RENAME has not reduced
394 * profiling time and hence has been removed in the interest
395 * of simplicity.
396 */
397 if (nameiop != LOOKUP || i_diroff == 0 ||
398 i_diroff > dp->i_size) {
399 entryoffsetinblock = 0;
400 i_offset = 0;
401 numdirpasses = 1;
402 } else {
403 i_offset = i_diroff;
404 if ((entryoffsetinblock = i_offset & bmask) &&
405 (error = ext2_blkatoff(vdp, (off_t)i_offset, NULL,
406 &bp)))
407 return (error);
408 numdirpasses = 2;
409 nchstats.ncs_2passes++;
410 }
411 prevoff = i_offset;
412 endsearch = roundup2(dp->i_size, DIRBLKSIZ);
413 enduseful = 0;
414
415 searchloop:
416 while (i_offset < endsearch) {
417 /*
418 * If necessary, get the next directory block.
419 */
420 if (bp != NULL)
421 brelse(bp);
422 error = ext2_blkatoff(vdp, (off_t)i_offset, NULL, &bp);
423 if (error != 0)
424 return (error);
425 entryoffsetinblock = 0;
426 /*
427 * If still looking for a slot, and at a DIRBLKSIZE
428 * boundary, have to start looking for free space again.
429 */
430 if (ss.slotstatus == NONE &&
431 (entryoffsetinblock & (DIRBLKSIZ - 1)) == 0) {
432 ss.slotoffset = -1;
433 ss.slotfreespace = 0;
434 }
435 error = ext2_search_dirblock(dp, bp->b_data, &entry_found,
436 cnp->cn_nameptr, cnp->cn_namelen,
437 &entryoffsetinblock, &i_offset, &prevoff,
438 &enduseful, &ss);
439 if (error != 0) {
440 brelse(bp);
441 return (error);
442 }
443 if (entry_found) {
444 ep = (struct ext2fs_direct_2 *)((char *)bp->b_data +
445 (entryoffsetinblock & bmask));
446 foundentry:
447 ino = ep->e2d_ino;
448 goto found;
449 }
450 }
451 notfound:
452 /*
453 * If we started in the middle of the directory and failed
454 * to find our target, we must check the beginning as well.
455 */
456 if (numdirpasses == 2) {
457 numdirpasses--;
458 i_offset = 0;
459 endsearch = i_diroff;
460 goto searchloop;
461 }
462 if (bp != NULL)
463 brelse(bp);
464 /*
465 * If creating, and at end of pathname and current
466 * directory has not been removed, then can consider
467 * allowing file to be created.
468 */
469 if ((nameiop == CREATE || nameiop == RENAME) &&
470 (flags & ISLASTCN) && dp->i_nlink != 0) {
471 /*
472 * Access for write is interpreted as allowing
473 * creation of files in the directory.
474 */
475 if ((error = VOP_ACCESS(vdp, VWRITE, cred, cnp->cn_thread)) != 0)
476 return (error);
477 /*
478 * Return an indication of where the new directory
479 * entry should be put. If we didn't find a slot,
480 * then set dp->i_count to 0 indicating
481 * that the new slot belongs at the end of the
482 * directory. If we found a slot, then the new entry
483 * can be put in the range from dp->i_offset to
484 * dp->i_offset + dp->i_count.
485 */
486 if (ss.slotstatus == NONE) {
487 dp->i_offset = roundup2(dp->i_size, DIRBLKSIZ);
488 dp->i_count = 0;
489 enduseful = dp->i_offset;
490 } else {
491 dp->i_offset = ss.slotoffset;
492 dp->i_count = ss.slotsize;
493 if (enduseful < ss.slotoffset + ss.slotsize)
494 enduseful = ss.slotoffset + ss.slotsize;
495 }
496 dp->i_endoff = roundup2(enduseful, DIRBLKSIZ);
497 /*
498 * We return with the directory locked, so that
499 * the parameters we set up above will still be
500 * valid if we actually decide to do a direnter().
501 * We return ni_vp == NULL to indicate that the entry
502 * does not currently exist; we leave a pointer to
503 * the (locked) directory inode in ndp->ni_dvp.
504 * The pathname buffer is saved so that the name
505 * can be obtained later.
506 *
507 * NB - if the directory is unlocked, then this
508 * information cannot be used.
509 */
510 cnp->cn_flags |= SAVENAME;
511 return (EJUSTRETURN);
512 }
513 /*
514 * Insert name into cache (as non-existent) if appropriate.
515 */
516 if ((cnp->cn_flags & MAKEENTRY) != 0)
517 cache_enter(vdp, NULL, cnp);
518 return (ENOENT);
519
520 found:
521 if (dd_ino != NULL)
522 *dd_ino = ino;
523 if (numdirpasses == 2)
524 nchstats.ncs_pass2++;
525 /*
526 * Check that directory length properly reflects presence
527 * of this entry.
528 */
529 if (entryoffsetinblock + EXT2_DIR_REC_LEN(ep->e2d_namlen)
530 > dp->i_size) {
531 ext2_dirbad(dp, i_offset, "i_size too small");
532 dp->i_size = entryoffsetinblock + EXT2_DIR_REC_LEN(ep->e2d_namlen);
533 dp->i_flag |= IN_CHANGE | IN_UPDATE;
534 }
535 brelse(bp);
536
537 /*
538 * Found component in pathname.
539 * If the final component of path name, save information
540 * in the cache as to where the entry was found.
541 */
542 if ((flags & ISLASTCN) && nameiop == LOOKUP)
543 dp->i_diroff = rounddown2(i_offset, DIRBLKSIZ);
544 /*
545 * If deleting, and at end of pathname, return
546 * parameters which can be used to remove file.
547 */
548 if (nameiop == DELETE && (flags & ISLASTCN)) {
549 if (flags & LOCKPARENT)
550 ASSERT_VOP_ELOCKED(vdp, __FUNCTION__);
551 /*
552 * Write access to directory required to delete files.
553 */
554 if ((error = VOP_ACCESS(vdp, VWRITE, cred, cnp->cn_thread)) != 0)
555 return (error);
556 /*
557 * Return pointer to current entry in dp->i_offset,
558 * and distance past previous entry (if there
559 * is a previous entry in this block) in dp->i_count.
560 * Save directory inode pointer in ndp->ni_dvp for dirremove().
561 *
562 * Technically we shouldn't be setting these in the
563 * WANTPARENT case (first lookup in rename()), but any
564 * lookups that will result in directory changes will
565 * overwrite these.
566 */
567 dp->i_offset = i_offset;
568 if ((dp->i_offset & (DIRBLKSIZ - 1)) == 0)
569 dp->i_count = 0;
570 else
571 dp->i_count = dp->i_offset - prevoff;
572 if (dd_ino != NULL)
573 return (0);
574 if (dp->i_number == ino) {
575 VREF(vdp);
576 *vpp = vdp;
577 return (0);
578 }
579 if ((error = VFS_VGET(vdp->v_mount, ino, LK_EXCLUSIVE,
580 &tdp)) != 0)
581 return (error);
582 /*
583 * If directory is "sticky", then user must own
584 * the directory, or the file in it, else she
585 * may not delete it (unless she's root). This
586 * implements append-only directories.
587 */
588 if ((dp->i_mode & ISVTX) &&
589 cred->cr_uid != 0 &&
590 cred->cr_uid != dp->i_uid &&
591 VTOI(tdp)->i_uid != cred->cr_uid) {
592 vput(tdp);
593 return (EPERM);
594 }
595 *vpp = tdp;
596 return (0);
597 }
598
599 /*
600 * If rewriting (RENAME), return the inode and the
601 * information required to rewrite the present directory
602 * Must get inode of directory entry to verify it's a
603 * regular file, or empty directory.
604 */
605 if (nameiop == RENAME && (flags & ISLASTCN)) {
606 if ((error = VOP_ACCESS(vdp, VWRITE, cred, cnp->cn_thread)) != 0)
607 return (error);
608 /*
609 * Careful about locking second inode.
610 * This can only occur if the target is ".".
611 */
612 dp->i_offset = i_offset;
613 if (dp->i_number == ino)
614 return (EISDIR);
615 if (dd_ino != NULL)
616 return (0);
617 if ((error = VFS_VGET(vdp->v_mount, ino, LK_EXCLUSIVE,
618 &tdp)) != 0)
619 return (error);
620 *vpp = tdp;
621 cnp->cn_flags |= SAVENAME;
622 return (0);
623 }
624 if (dd_ino != NULL)
625 return (0);
626
627 /*
628 * Step through the translation in the name. We do not `vput' the
629 * directory because we may need it again if a symbolic link
630 * is relative to the current directory. Instead we save it
631 * unlocked as "pdp". We must get the target inode before unlocking
632 * the directory to insure that the inode will not be removed
633 * before we get it. We prevent deadlock by always fetching
634 * inodes from the root, moving down the directory tree. Thus
635 * when following backward pointers ".." we must unlock the
636 * parent directory before getting the requested directory.
637 * There is a potential race condition here if both the current
638 * and parent directories are removed before the VFS_VGET for the
639 * inode associated with ".." returns. We hope that this occurs
640 * infrequently since we cannot avoid this race condition without
641 * implementing a sophisticated deadlock detection algorithm.
642 * Note also that this simple deadlock detection scheme will not
643 * work if the file system has any hard links other than ".."
644 * that point backwards in the directory structure.
645 */
646 pdp = vdp;
647 if (flags & ISDOTDOT) {
648 error = vn_vget_ino(pdp, ino, cnp->cn_lkflags, &tdp);
649 if (pdp->v_iflag & VI_DOOMED) {
650 if (error == 0)
651 vput(tdp);
652 error = ENOENT;
653 }
654 if (error)
655 return (error);
656 /*
657 * Recheck that ".." entry in the vdp directory points
658 * to the inode we looked up before vdp lock was
659 * dropped.
660 */
661 error = ext2_lookup_ino(pdp, NULL, cnp, &ino1);
662 if (error) {
663 vput(tdp);
664 return (error);
665 }
666 if (ino1 != ino) {
667 vput(tdp);
668 goto restart;
669 }
670 *vpp = tdp;
671 } else if (dp->i_number == ino) {
672 VREF(vdp); /* we want ourself, ie "." */
673 /*
674 * When we lookup "." we still can be asked to lock it
675 * differently.
676 */
677 ltype = cnp->cn_lkflags & LK_TYPE_MASK;
678 if (ltype != VOP_ISLOCKED(vdp)) {
679 if (ltype == LK_EXCLUSIVE)
680 vn_lock(vdp, LK_UPGRADE | LK_RETRY);
681 else /* if (ltype == LK_SHARED) */
682 vn_lock(vdp, LK_DOWNGRADE | LK_RETRY);
683 }
684 *vpp = vdp;
685 } else {
686 if ((error = VFS_VGET(vdp->v_mount, ino, cnp->cn_lkflags,
687 &tdp)) != 0)
688 return (error);
689 *vpp = tdp;
690 }
691
692 /*
693 * Insert name into cache if appropriate.
694 */
695 if (cnp->cn_flags & MAKEENTRY)
696 cache_enter(vdp, *vpp, cnp);
697 return (0);
698 }
699
700 int
701 ext2_search_dirblock(struct inode *ip, void *data, int *foundp,
702 const char *name, int namelen, int *entryoffsetinblockp,
703 doff_t *offp, doff_t *prevoffp, doff_t *endusefulp,
704 struct ext2fs_searchslot *ssp)
705 {
706 struct vnode *vdp;
707 struct ext2fs_direct_2 *ep, *top;
708 uint32_t bsize = ip->i_e2fs->e2fs_bsize;
709 int offset = *entryoffsetinblockp;
710 int namlen;
711
712 vdp = ITOV(ip);
713
714 ep = (struct ext2fs_direct_2 *)((char *)data + offset);
715 top = (struct ext2fs_direct_2 *)((char *)data +
716 bsize - EXT2_DIR_REC_LEN(0));
717
718 while (ep < top) {
719 /*
720 * Full validation checks are slow, so we only check
721 * enough to insure forward progress through the
722 * directory. Complete checks can be run by setting
723 * "vfs.e2fs.dirchk" to be true.
724 */
725 if (ep->e2d_reclen == 0 ||
726 (dirchk && ext2_dirbadentry(vdp, ep, offset))) {
727 int i;
728
729 ext2_dirbad(ip, *offp, "mangled entry");
730 i = bsize - (offset & (bsize - 1));
731 *offp += i;
732 offset += i;
733 continue;
734 }
735
736 /*
737 * If an appropriate sized slot has not yet been found,
738 * check to see if one is available. Also accumulate space
739 * in the current block so that we can determine if
740 * compaction is viable.
741 */
742 if (ssp->slotstatus != FOUND) {
743 int size = ep->e2d_reclen;
744
745 if (ep->e2d_ino != 0)
746 size -= EXT2_DIR_REC_LEN(ep->e2d_namlen);
747 if (size > 0) {
748 if (size >= ssp->slotneeded) {
749 ssp->slotstatus = FOUND;
750 ssp->slotoffset = *offp;
751 ssp->slotsize = ep->e2d_reclen;
752 } else if (ssp->slotstatus == NONE) {
753 ssp->slotfreespace += size;
754 if (ssp->slotoffset == -1)
755 ssp->slotoffset = *offp;
756 if (ssp->slotfreespace >= ssp->slotneeded) {
757 ssp->slotstatus = COMPACT;
758 ssp->slotsize = *offp +
759 ep->e2d_reclen -
760 ssp->slotoffset;
761 }
762 }
763 }
764 }
765 /*
766 * Check for a name match.
767 */
768 if (ep->e2d_ino) {
769 namlen = ep->e2d_namlen;
770 if (namlen == namelen &&
771 !bcmp(name, ep->e2d_name, (unsigned)namlen)) {
772 /*
773 * Save directory entry's inode number and
774 * reclen in ndp->ni_ufs area, and release
775 * directory buffer.
776 */
777 *foundp = 1;
778 return (0);
779 }
780 }
781 *prevoffp = *offp;
782 *offp += ep->e2d_reclen;
783 offset += ep->e2d_reclen;
784 *entryoffsetinblockp = offset;
785 if (ep->e2d_ino)
786 *endusefulp = *offp;
787 /*
788 * Get pointer to the next entry.
789 */
790 ep = (struct ext2fs_direct_2 *)((char *)data + offset);
791 }
792
793 return (0);
794 }
795
796 void
797 ext2_dirbad(struct inode *ip, doff_t offset, char *how)
798 {
799 struct mount *mp;
800
801 mp = ITOV(ip)->v_mount;
802 if ((mp->mnt_flag & MNT_RDONLY) == 0)
803 panic("ext2_dirbad: %s: bad dir ino %ju at offset %ld: %s\n",
804 mp->mnt_stat.f_mntonname, (uintmax_t)ip->i_number,
805 (long)offset, how);
806 else
807 (void)printf("%s: bad dir ino %ju at offset %ld: %s\n",
808 mp->mnt_stat.f_mntonname, (uintmax_t)ip->i_number,
809 (long)offset, how);
810
811 }
812
813 /*
814 * Do consistency checking on a directory entry:
815 * record length must be multiple of 4
816 * entry must fit in rest of its DIRBLKSIZ block
817 * record must be large enough to contain entry
818 * name is not longer than MAXNAMLEN
819 * name must be as long as advertised, and null terminated
820 */
821 /*
822 * changed so that it confirms to ext2_check_dir_entry
823 */
824 static int
825 ext2_dirbadentry(struct vnode *dp, struct ext2fs_direct_2 *de,
826 int entryoffsetinblock)
827 {
828 int DIRBLKSIZ = VTOI(dp)->i_e2fs->e2fs_bsize;
829
830 char *error_msg = NULL;
831
832 if (de->e2d_reclen < EXT2_DIR_REC_LEN(1))
833 error_msg = "rec_len is smaller than minimal";
834 else if (de->e2d_reclen % 4 != 0)
835 error_msg = "rec_len % 4 != 0";
836 else if (de->e2d_reclen < EXT2_DIR_REC_LEN(de->e2d_namlen))
837 error_msg = "reclen is too small for name_len";
838 else if (entryoffsetinblock + de->e2d_reclen > DIRBLKSIZ)
839 error_msg = "directory entry across blocks";
840 /* else LATER
841 if (de->inode > dir->i_sb->u.ext2_sb.s_es->s_inodes_count)
842 error_msg = "inode out of bounds";
843 */
844
845 if (error_msg != NULL) {
846 printf("bad directory entry: %s\n", error_msg);
847 printf("offset=%d, inode=%lu, rec_len=%u, name_len=%u\n",
848 entryoffsetinblock, (unsigned long)de->e2d_ino,
849 de->e2d_reclen, de->e2d_namlen);
850 }
851 return error_msg == NULL ? 0 : 1;
852 }
853
854 /*
855 * Write a directory entry after a call to namei, using the parameters
856 * that it left in nameidata. The argument ip is the inode which the new
857 * directory entry will refer to. Dvp is a pointer to the directory to
858 * be written, which was left locked by namei. Remaining parameters
859 * (dp->i_offset, dp->i_count) indicate how the space for the new
860 * entry is to be obtained.
861 */
862 int
863 ext2_direnter(struct inode *ip, struct vnode *dvp, struct componentname *cnp)
864 {
865 struct inode *dp;
866 struct ext2fs_direct_2 newdir;
867 struct iovec aiov;
868 struct uio auio;
869 int error, newentrysize;
870 int DIRBLKSIZ = ip->i_e2fs->e2fs_bsize;
871
872
873 #ifdef INVARIANTS
874 if ((cnp->cn_flags & SAVENAME) == 0)
875 panic("ext2_direnter: missing name");
876 #endif
877 dp = VTOI(dvp);
878 newdir.e2d_ino = ip->i_number;
879 newdir.e2d_namlen = cnp->cn_namelen;
880 if (EXT2_HAS_INCOMPAT_FEATURE(ip->i_e2fs,
881 EXT2F_INCOMPAT_FTYPE))
882 newdir.e2d_type = DTTOFT(IFTODT(ip->i_mode));
883 else
884 newdir.e2d_type = EXT2_FT_UNKNOWN;
885 bcopy(cnp->cn_nameptr, newdir.e2d_name, (unsigned)cnp->cn_namelen + 1);
886 newentrysize = EXT2_DIR_REC_LEN(newdir.e2d_namlen);
887
888 if (ext2_htree_has_idx(dp)) {
889 error = ext2_htree_add_entry(dvp, &newdir, cnp);
890 if (error) {
891 dp->i_flag &= ~IN_E3INDEX;
892 dp->i_flag |= IN_CHANGE | IN_UPDATE;
893 }
894 return (error);
895 }
896
897 if (EXT2_HAS_COMPAT_FEATURE(ip->i_e2fs, EXT2F_COMPAT_DIRHASHINDEX) &&
898 !ext2_htree_has_idx(dp)) {
899 if ((dp->i_size / DIRBLKSIZ) == 1 &&
900 dp->i_offset == DIRBLKSIZ) {
901 /*
902 * Making indexed directory when one block is not
903 * enough to save all entries.
904 */
905 return ext2_htree_create_index(dvp, cnp, &newdir);
906 }
907 }
908
909 if (dp->i_count == 0) {
910 /*
911 * If dp->i_count is 0, then namei could find no
912 * space in the directory. Here, dp->i_offset will
913 * be on a directory block boundary and we will write the
914 * new entry into a fresh block.
915 */
916 if (dp->i_offset & (DIRBLKSIZ - 1))
917 panic("ext2_direnter: newblk");
918 auio.uio_offset = dp->i_offset;
919 newdir.e2d_reclen = DIRBLKSIZ;
920 auio.uio_resid = newentrysize;
921 aiov.iov_len = newentrysize;
922 aiov.iov_base = (caddr_t)&newdir;
923 auio.uio_iov = &aiov;
924 auio.uio_iovcnt = 1;
925 auio.uio_rw = UIO_WRITE;
926 auio.uio_segflg = UIO_SYSSPACE;
927 auio.uio_td = (struct thread *)0;
928 error = VOP_WRITE(dvp, &auio, IO_SYNC, cnp->cn_cred);
929 if (DIRBLKSIZ >
930 VFSTOEXT2(dvp->v_mount)->um_mountp->mnt_stat.f_bsize)
931 /* XXX should grow with balloc() */
932 panic("ext2_direnter: frag size");
933 else if (!error) {
934 dp->i_size = roundup2(dp->i_size, DIRBLKSIZ);
935 dp->i_flag |= IN_CHANGE;
936 }
937 return (error);
938 }
939
940 error = ext2_add_entry(dvp, &newdir);
941 if (!error && dp->i_endoff && dp->i_endoff < dp->i_size)
942 error = ext2_truncate(dvp, (off_t)dp->i_endoff, IO_SYNC,
943 cnp->cn_cred, cnp->cn_thread);
944 return (error);
945 }
946
947 /*
948 * Insert an entry into the directory block.
949 * Compact the contents.
950 */
951 int
952 ext2_add_entry(struct vnode *dvp, struct ext2fs_direct_2 *entry)
953 {
954 struct ext2fs_direct_2 *ep, *nep;
955 struct inode *dp;
956 struct buf *bp;
957 u_int dsize;
958 int error, loc, newentrysize, spacefree;
959 char *dirbuf;
960
961 dp = VTOI(dvp);
962
963 /*
964 * If dp->i_count is non-zero, then namei found space
965 * for the new entry in the range dp->i_offset to
966 * dp->i_offset + dp->i_count in the directory.
967 * To use this space, we may have to compact the entries located
968 * there, by copying them together towards the beginning of the
969 * block, leaving the free space in one usable chunk at the end.
970 */
971
972 /*
973 * Increase size of directory if entry eats into new space.
974 * This should never push the size past a new multiple of
975 * DIRBLKSIZE.
976 *
977 * N.B. - THIS IS AN ARTIFACT OF 4.2 AND SHOULD NEVER HAPPEN.
978 */
979 if (dp->i_offset + dp->i_count > dp->i_size)
980 dp->i_size = dp->i_offset + dp->i_count;
981 /*
982 * Get the block containing the space for the new directory entry.
983 */
984 if ((error = ext2_blkatoff(dvp, (off_t)dp->i_offset, &dirbuf,
985 &bp)) != 0)
986 return (error);
987 /*
988 * Find space for the new entry. In the simple case, the entry at
989 * offset base will have the space. If it does not, then namei
990 * arranged that compacting the region dp->i_offset to
991 * dp->i_offset + dp->i_count would yield the
992 * space.
993 */
994 newentrysize = EXT2_DIR_REC_LEN(entry->e2d_namlen);
995 ep = (struct ext2fs_direct_2 *)dirbuf;
996 dsize = EXT2_DIR_REC_LEN(ep->e2d_namlen);
997 spacefree = ep->e2d_reclen - dsize;
998 for (loc = ep->e2d_reclen; loc < dp->i_count; ) {
999 nep = (struct ext2fs_direct_2 *)(dirbuf + loc);
1000 if (ep->e2d_ino) {
1001 /* trim the existing slot */
1002 ep->e2d_reclen = dsize;
1003 ep = (struct ext2fs_direct_2 *)((char *)ep + dsize);
1004 } else {
1005 /* overwrite; nothing there; header is ours */
1006 spacefree += dsize;
1007 }
1008 dsize = EXT2_DIR_REC_LEN(nep->e2d_namlen);
1009 spacefree += nep->e2d_reclen - dsize;
1010 loc += nep->e2d_reclen;
1011 bcopy((caddr_t)nep, (caddr_t)ep, dsize);
1012 }
1013 /*
1014 * Update the pointer fields in the previous entry (if any),
1015 * copy in the new entry, and write out the block.
1016 */
1017 if (ep->e2d_ino == 0) {
1018 if (spacefree + dsize < newentrysize)
1019 panic("ext2_direnter: compact1");
1020 entry->e2d_reclen = spacefree + dsize;
1021 } else {
1022 if (spacefree < newentrysize)
1023 panic("ext2_direnter: compact2");
1024 entry->e2d_reclen = spacefree;
1025 ep->e2d_reclen = dsize;
1026 ep = (struct ext2fs_direct_2 *)((char *)ep + dsize);
1027 }
1028 bcopy((caddr_t)entry, (caddr_t)ep, (u_int)newentrysize);
1029 if (DOINGASYNC(dvp)) {
1030 bdwrite(bp);
1031 error = 0;
1032 } else {
1033 error = bwrite(bp);
1034 }
1035 dp->i_flag |= IN_CHANGE | IN_UPDATE;
1036 return (error);
1037 }
1038
1039 /*
1040 * Remove a directory entry after a call to namei, using
1041 * the parameters which it left in nameidata. The entry
1042 * dp->i_offset contains the offset into the directory of the
1043 * entry to be eliminated. The dp->i_count field contains the
1044 * size of the previous record in the directory. If this
1045 * is 0, the first entry is being deleted, so we need only
1046 * zero the inode number to mark the entry as free. If the
1047 * entry is not the first in the directory, we must reclaim
1048 * the space of the now empty record by adding the record size
1049 * to the size of the previous entry.
1050 */
1051 int
1052 ext2_dirremove(struct vnode *dvp, struct componentname *cnp)
1053 {
1054 struct inode *dp;
1055 struct ext2fs_direct_2 *ep, *rep;
1056 struct buf *bp;
1057 int error;
1058
1059 dp = VTOI(dvp);
1060 if (dp->i_count == 0) {
1061 /*
1062 * First entry in block: set d_ino to zero.
1063 */
1064 if ((error =
1065 ext2_blkatoff(dvp, (off_t)dp->i_offset, (char **)&ep,
1066 &bp)) != 0)
1067 return (error);
1068 ep->e2d_ino = 0;
1069 error = bwrite(bp);
1070 dp->i_flag |= IN_CHANGE | IN_UPDATE;
1071 return (error);
1072 }
1073 /*
1074 * Collapse new free space into previous entry.
1075 */
1076 if ((error = ext2_blkatoff(dvp, (off_t)(dp->i_offset - dp->i_count),
1077 (char **)&ep, &bp)) != 0)
1078 return (error);
1079
1080 /* Set 'rep' to the entry being removed. */
1081 if (dp->i_count == 0)
1082 rep = ep;
1083 else
1084 rep = (struct ext2fs_direct_2 *)((char *)ep + ep->e2d_reclen);
1085 ep->e2d_reclen += rep->e2d_reclen;
1086 if (DOINGASYNC(dvp) && dp->i_count != 0)
1087 bdwrite(bp);
1088 else
1089 error = bwrite(bp);
1090 dp->i_flag |= IN_CHANGE | IN_UPDATE;
1091 return (error);
1092 }
1093
1094 /*
1095 * Rewrite an existing directory entry to point at the inode
1096 * supplied. The parameters describing the directory entry are
1097 * set up by a call to namei.
1098 */
1099 int
1100 ext2_dirrewrite(struct inode *dp, struct inode *ip, struct componentname *cnp)
1101 {
1102 struct buf *bp;
1103 struct ext2fs_direct_2 *ep;
1104 struct vnode *vdp = ITOV(dp);
1105 int error;
1106
1107 if ((error = ext2_blkatoff(vdp, (off_t)dp->i_offset, (char **)&ep,
1108 &bp)) != 0)
1109 return (error);
1110 ep->e2d_ino = ip->i_number;
1111 if (EXT2_HAS_INCOMPAT_FEATURE(ip->i_e2fs,
1112 EXT2F_INCOMPAT_FTYPE))
1113 ep->e2d_type = DTTOFT(IFTODT(ip->i_mode));
1114 else
1115 ep->e2d_type = EXT2_FT_UNKNOWN;
1116 error = bwrite(bp);
1117 dp->i_flag |= IN_CHANGE | IN_UPDATE;
1118 return (error);
1119 }
1120
1121 /*
1122 * Check if a directory is empty or not.
1123 * Inode supplied must be locked.
1124 *
1125 * Using a struct dirtemplate here is not precisely
1126 * what we want, but better than using a struct direct.
1127 *
1128 * NB: does not handle corrupted directories.
1129 */
1130 int
1131 ext2_dirempty(struct inode *ip, ino_t parentino, struct ucred *cred)
1132 {
1133 off_t off;
1134 struct dirtemplate dbuf;
1135 struct ext2fs_direct_2 *dp = (struct ext2fs_direct_2 *)&dbuf;
1136 int error, namlen;
1137 ssize_t count;
1138 #define MINDIRSIZ (sizeof(struct dirtemplate) / 2)
1139
1140 for (off = 0; off < ip->i_size; off += dp->e2d_reclen) {
1141 error = vn_rdwr(UIO_READ, ITOV(ip), (caddr_t)dp, MINDIRSIZ,
1142 off, UIO_SYSSPACE, IO_NODELOCKED | IO_NOMACCHECK, cred,
1143 NOCRED, &count, (struct thread *)0);
1144 /*
1145 * Since we read MINDIRSIZ, residual must
1146 * be 0 unless we're at end of file.
1147 */
1148 if (error || count != 0)
1149 return (0);
1150 /* avoid infinite loops */
1151 if (dp->e2d_reclen == 0)
1152 return (0);
1153 /* skip empty entries */
1154 if (dp->e2d_ino == 0)
1155 continue;
1156 /* accept only "." and ".." */
1157 namlen = dp->e2d_namlen;
1158 if (namlen > 2)
1159 return (0);
1160 if (dp->e2d_name[0] != '.')
1161 return (0);
1162 /*
1163 * At this point namlen must be 1 or 2.
1164 * 1 implies ".", 2 implies ".." if second
1165 * char is also "."
1166 */
1167 if (namlen == 1)
1168 continue;
1169 if (dp->e2d_name[1] == '.' && dp->e2d_ino == parentino)
1170 continue;
1171 return (0);
1172 }
1173 return (1);
1174 }
1175
1176 /*
1177 * Check if source directory is in the path of the target directory.
1178 * Target is supplied locked, source is unlocked.
1179 * The target is always vput before returning.
1180 */
1181 int
1182 ext2_checkpath(struct inode *source, struct inode *target, struct ucred *cred)
1183 {
1184 struct vnode *vp;
1185 int error, namlen;
1186 struct dirtemplate dirbuf;
1187
1188 vp = ITOV(target);
1189 if (target->i_number == source->i_number) {
1190 error = EEXIST;
1191 goto out;
1192 }
1193 if (target->i_number == EXT2_ROOTINO) {
1194 error = 0;
1195 goto out;
1196 }
1197
1198 for (;;) {
1199 if (vp->v_type != VDIR) {
1200 error = ENOTDIR;
1201 break;
1202 }
1203 error = vn_rdwr(UIO_READ, vp, (caddr_t)&dirbuf,
1204 sizeof(struct dirtemplate), (off_t)0, UIO_SYSSPACE,
1205 IO_NODELOCKED | IO_NOMACCHECK, cred, NOCRED, NULL,
1206 NULL);
1207 if (error != 0)
1208 break;
1209 namlen = dirbuf.dotdot_type; /* like ufs little-endian */
1210 if (namlen != 2 ||
1211 dirbuf.dotdot_name[0] != '.' ||
1212 dirbuf.dotdot_name[1] != '.') {
1213 error = ENOTDIR;
1214 break;
1215 }
1216 if (dirbuf.dotdot_ino == source->i_number) {
1217 error = EINVAL;
1218 break;
1219 }
1220 if (dirbuf.dotdot_ino == EXT2_ROOTINO)
1221 break;
1222 vput(vp);
1223 if ((error = VFS_VGET(vp->v_mount, dirbuf.dotdot_ino,
1224 LK_EXCLUSIVE, &vp)) != 0) {
1225 vp = NULL;
1226 break;
1227 }
1228 }
1229
1230 out:
1231 if (error == ENOTDIR)
1232 printf("checkpath: .. not a directory\n");
1233 if (vp != NULL)
1234 vput(vp);
1235 return (error);
1236 }
Cache object: 8f097f8c36f33cc844bfe54dd194f120
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