1 /* $OpenBSD: ext2fs_lookup.c,v 1.46 2022/01/11 03:13:59 jsg Exp $ */
2 /* $NetBSD: ext2fs_lookup.c,v 1.16 2000/08/03 20:29:26 thorpej Exp $ */
3
4 /*
5 * Modified for NetBSD 1.2E
6 * May 1997, Manuel Bouyer
7 * Laboratoire d'informatique de Paris VI
8 */
9 /*
10 * modified for Lites 1.1
11 *
12 * Aug 1995, Godmar Back (gback@cs.utah.edu)
13 * University of Utah, Department of Computer Science
14 */
15 /*
16 * Copyright (c) 1989, 1993
17 * The Regents of the University of California. All rights reserved.
18 * (c) UNIX System Laboratories, Inc.
19 * All or some portions of this file are derived from material licensed
20 * to the University of California by American Telephone and Telegraph
21 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
22 * the permission of UNIX System Laboratories, Inc.
23 *
24 * Redistribution and use in source and binary forms, with or without
25 * modification, are permitted provided that the following conditions
26 * are met:
27 * 1. Redistributions of source code must retain the above copyright
28 * notice, this list of conditions and the following disclaimer.
29 * 2. Redistributions in binary form must reproduce the above copyright
30 * notice, this list of conditions and the following disclaimer in the
31 * documentation and/or other materials provided with the distribution.
32 * 3. Neither the name of the University nor the names of its contributors
33 * may be used to endorse or promote products derived from this software
34 * without specific prior written permission.
35 *
36 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
37 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
38 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
39 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
40 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
41 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
42 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
43 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
44 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
45 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
46 * SUCH DAMAGE.
47 *
48 * @(#)ufs_lookup.c 8.6 (Berkeley) 4/1/94
49 */
50
51 #include <sys/param.h>
52 #include <sys/systm.h>
53 #include <sys/namei.h>
54 #include <sys/buf.h>
55 #include <sys/mount.h>
56 #include <sys/vnode.h>
57 #include <sys/malloc.h>
58 #include <sys/dirent.h>
59
60 #include <ufs/ufs/quota.h>
61 #include <ufs/ufs/inode.h>
62 #include <ufs/ufs/ufsmount.h>
63 #include <ufs/ufs/ufs_extern.h>
64
65 #include <ufs/ext2fs/ext2fs_extern.h>
66 #include <ufs/ext2fs/ext2fs_dir.h>
67 #include <ufs/ext2fs/ext2fs.h>
68
69 extern int dirchk;
70
71 static void ext2fs_dirconv2ffs(struct ext2fs_direct *e2dir,
72 struct dirent *ffsdir);
73 static int ext2fs_dirbadentry(struct vnode *dp, struct ext2fs_direct *de,
74 int entryoffsetinblock);
75 static int ext2fs_search_dirblock(struct inode *, void *, int *,
76 struct componentname *, int *, doff_t *, doff_t *,
77 struct ext2fs_searchslot *);
78
79 /*
80 * the problem that is tackled below is the fact that FFS
81 * includes the terminating zero on disk while EXT2FS doesn't
82 * this implies that we need to introduce some padding.
83 * For instance, a filename "sbin" has normally a reclen 12
84 * in EXT2, but 16 in FFS.
85 * This reminds me of that Pepsi commercial: 'Kid saved a lousy nine cents...'
86 * If it wasn't for that, the complete ufs code for directories would
87 * have worked w/o changes (except for the difference in DIRBLKSIZ)
88 */
89 static void
ext2fs_dirconv2ffs(struct ext2fs_direct * e2dir,struct dirent * ffsdir)90 ext2fs_dirconv2ffs(struct ext2fs_direct *e2dir, struct dirent *ffsdir)
91 {
92 memset(ffsdir, 0, sizeof(struct dirent));
93 ffsdir->d_fileno = letoh32(e2dir->e2d_ino);
94 ffsdir->d_namlen = e2dir->e2d_namlen;
95
96 ffsdir->d_type = DT_UNKNOWN; /* don't know more here */
97 #ifdef DIAGNOSTIC
98 /*
99 * XXX Right now this can't happen, but if one day
100 * MAXNAMLEN != E2FS_MAXNAMLEN we should handle this more gracefully !
101 */
102 /* XXX: e2d_namlen is to small for such comparison
103 if (e2dir->e2d_namlen > MAXNAMLEN)
104 panic("ext2fs: e2dir->e2d_namlen");
105 */
106 #endif
107 strncpy(ffsdir->d_name, e2dir->e2d_name, ffsdir->d_namlen);
108
109 /* Godmar thinks: since e2dir->e2d_reclen can be big and means
110 nothing anyway, we compute our own reclen according to what
111 we think is right
112 */
113 ffsdir->d_reclen = DIRENT_SIZE(ffsdir);
114 }
115
116 /*
117 * Vnode op for reading directories.
118 *
119 * Convert the on-disk entries to <sys/dirent.h> entries.
120 * the problem is that the conversion will blow up some entries by four bytes,
121 * so it can't be done in place. This is too bad. Right now the conversion is
122 * done entry by entry, the converted entry is sent via uiomove.
123 *
124 * XXX allocate a buffer, convert as many entries as possible, then send
125 * the whole buffer to uiomove
126 */
127 int
ext2fs_readdir(void * v)128 ext2fs_readdir(void *v)
129 {
130 struct vop_readdir_args *ap = v;
131 struct uio *uio = ap->a_uio;
132 int error;
133 size_t e2fs_count, readcnt, entries;
134 struct vnode *vp = ap->a_vp;
135 struct m_ext2fs *fs = VTOI(vp)->i_e2fs;
136
137 struct ext2fs_direct *dp;
138 struct dirent dstd;
139 struct uio auio;
140 struct iovec aiov;
141 caddr_t dirbuf;
142 off_t off = uio->uio_offset;
143 int e2d_reclen;
144
145 if (vp->v_type != VDIR)
146 return (ENOTDIR);
147
148 e2fs_count = uio->uio_resid;
149 entries = (uio->uio_offset + e2fs_count) & (fs->e2fs_bsize - 1);
150
151 /* Make sure we don't return partial entries. */
152 if (e2fs_count <= entries)
153 return (EINVAL);
154
155 e2fs_count -= entries;
156 auio = *uio;
157 auio.uio_iov = &aiov;
158 auio.uio_iovcnt = 1;
159 auio.uio_segflg = UIO_SYSSPACE;
160 aiov.iov_len = e2fs_count;
161 auio.uio_resid = e2fs_count;
162 dirbuf = malloc(e2fs_count, M_TEMP, M_WAITOK | M_ZERO);
163 aiov.iov_base = dirbuf;
164
165 error = VOP_READ(ap->a_vp, &auio, 0, ap->a_cred);
166 if (error == 0) {
167 readcnt = e2fs_count - auio.uio_resid;
168 dp = (struct ext2fs_direct *) dirbuf;
169 while ((char *) dp < (char *) dirbuf + readcnt) {
170 e2d_reclen = letoh16(dp->e2d_reclen);
171 if (e2d_reclen == 0) {
172 error = EIO;
173 break;
174 }
175 ext2fs_dirconv2ffs(dp, &dstd);
176 if(dstd.d_reclen > uio->uio_resid) {
177 break;
178 }
179 dstd.d_off = off + e2d_reclen;
180 if ((error = uiomove((caddr_t)&dstd, dstd.d_reclen, uio)) != 0) {
181 break;
182 }
183 off = off + e2d_reclen;
184 /* advance dp */
185 dp = (struct ext2fs_direct *) ((char *)dp + e2d_reclen);
186 }
187 /* we need to correct uio_offset */
188 uio->uio_offset = off;
189 }
190 free(dirbuf, M_TEMP, e2fs_count);
191 *ap->a_eofflag = ext2fs_size(VTOI(ap->a_vp)) <= uio->uio_offset;
192 return (error);
193 }
194
195 /*
196 * Convert a component of a pathname into a pointer to a locked inode.
197 * This is a very central and rather complicated routine.
198 * If the file system is not maintained in a strict tree hierarchy,
199 * this can result in a deadlock situation (see comments in code below).
200 *
201 * The cnp->cn_nameiop argument is LOOKUP, CREATE, RENAME, or DELETE depending
202 * on whether the name is to be looked up, created, renamed, or deleted.
203 * When CREATE, RENAME, or DELETE is specified, information usable in
204 * creating, renaming, or deleting a directory entry may be calculated.
205 * If flag has LOCKPARENT or'ed into it and the target of the pathname
206 * exists, lookup returns both the target and its parent directory locked.
207 * When creating or renaming and LOCKPARENT is specified, the target may
208 * not be ".". When deleting and LOCKPARENT is specified, the target may
209 * be "."., but the caller must check to ensure it does an vrele and vput
210 * instead of two vputs.
211 *
212 * Overall outline of ext2fs_lookup:
213 *
214 * check accessibility of directory
215 * look for name in cache, if found, then if at end of path
216 * and deleting or creating, drop it, else return name
217 * search for name in directory, to found or notfound
218 * notfound:
219 * if creating, return locked directory, leaving info on available slots
220 * else return error
221 * found:
222 * if at end of path and deleting, return information to allow delete
223 * if at end of path and rewriting (RENAME and LOCKPARENT), lock target
224 * inode and return info to allow rewrite
225 * if not at end, add name to cache; if at end and neither creating
226 * nor deleting, add name to cache
227 */
228 int
ext2fs_lookup(void * v)229 ext2fs_lookup(void *v)
230 {
231 struct vop_lookup_args *ap = v;
232 struct vnode *vdp; /* vnode for directory being searched */
233 struct inode *dp; /* inode for directory being searched */
234 struct buf *bp; /* a buffer of directory entries */
235 struct ext2fs_direct *ep; /* the current directory entry */
236 int entryoffsetinblock; /* offset of ep in bp's buffer */
237 struct ext2fs_searchslot ss;
238 int numdirpasses; /* strategy for directory search */
239 doff_t endsearch; /* offset to end directory search */
240 doff_t prevoff; /* prev entry dp->i_offset */
241 struct vnode *pdp; /* saved dp during symlink work */
242 struct vnode *tdp; /* returned by VFS_VGET */
243 doff_t enduseful; /* pointer past last used dir slot */
244 u_long bmask; /* block offset mask */
245 int lockparent; /* 1 => lockparent flag is set */
246 int wantparent; /* 1 => wantparent or lockparent flag */
247 struct vnode **vpp = ap->a_vpp;
248 struct componentname *cnp = ap->a_cnp;
249 struct ucred *cred = cnp->cn_cred;
250 int flags = cnp->cn_flags;
251 int nameiop = cnp->cn_nameiop;
252 int dirblksize, entry_found = 0, error;
253
254 ss.slotstatus = FOUND;
255 ss.slotoffset = -1;
256 ss.slotfreespace = ss.slotsize = ss.slotneeded = 0;
257
258 bp = NULL;
259 *vpp = NULL;
260 vdp = ap->a_dvp;
261 dp = VTOI(vdp);
262 dirblksize = dp->i_e2fs->e2fs_bsize;
263 lockparent = flags & LOCKPARENT;
264 wantparent = flags & (LOCKPARENT|WANTPARENT);
265
266 /*
267 * Check accessibility of directory.
268 */
269 if ((error = VOP_ACCESS(vdp, VEXEC, cred, cnp->cn_proc)) != 0)
270 return (error);
271
272 if ((flags & ISLASTCN) && (vdp->v_mount->mnt_flag & MNT_RDONLY) &&
273 (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME))
274 return (EROFS);
275
276 /*
277 * We now have a segment name to search for, and a directory to search.
278 *
279 * Before tediously performing a linear scan of the directory,
280 * check the name cache to see if the directory/name pair
281 * we are looking for is known already.
282 */
283 if ((error = cache_lookup(vdp, vpp, cnp)) >= 0)
284 return (error);
285
286 /*
287 * Suppress search for slots unless creating
288 * file and at end of pathname, in which case
289 * we watch for a place to put the new file in
290 * case it doesn't already exist.
291 */
292 if ((nameiop == CREATE || nameiop == RENAME) && (flags & ISLASTCN)) {
293 ss.slotstatus = NONE;
294 ss.slotneeded = EXT2FS_DIRSIZ(cnp->cn_namelen);
295 }
296
297 /*
298 * If there is cached information on a previous search of
299 * this directory, pick up where we last left off.
300 * We cache only lookups as these are the most common
301 * and have the greatest payoff. Caching CREATE has little
302 * benefit as it usually must search the entire directory
303 * to determine that the entry does not exist. Caching the
304 * location of the last DELETE or RENAME has not reduced
305 * profiling time and hence has been removed in the interest
306 * of simplicity.
307 */
308 bmask = VFSTOUFS(vdp->v_mount)->um_mountp->mnt_stat.f_iosize - 1;
309 if (nameiop != LOOKUP || dp->i_diroff == 0 ||
310 dp->i_diroff > ext2fs_size(dp)) {
311 entryoffsetinblock = 0;
312 dp->i_offset = 0;
313 numdirpasses = 1;
314 } else {
315 dp->i_offset = dp->i_diroff;
316 if ((entryoffsetinblock = dp->i_offset & bmask) &&
317 (error = ext2fs_bufatoff(dp, (off_t)dp->i_offset,
318 NULL, &bp)))
319 return (error);
320 numdirpasses = 2;
321 }
322 prevoff = dp->i_offset;
323 endsearch = roundup(ext2fs_size(dp), dirblksize);
324 enduseful = 0;
325
326 searchloop:
327 while (dp->i_offset < endsearch) {
328 /*
329 * If necessary, get the next directory block.
330 */
331 if (bp != NULL)
332 brelse(bp);
333
334 error = ext2fs_bufatoff(dp, (off_t)dp->i_offset, NULL, &bp);
335 if (error != 0)
336 return (error);
337 entryoffsetinblock = 0;
338
339 /*
340 * If still looking for a slot, and at a dirblksize
341 * boundary, have to start looking for free space again.
342 */
343 if (ss.slotstatus == NONE) {
344 ss.slotoffset = -1;
345 ss.slotfreespace = 0;
346 }
347
348 error = ext2fs_search_dirblock(dp, bp->b_data, &entry_found,
349 cnp, &entryoffsetinblock, &prevoff, &enduseful, &ss);
350 if (error) {
351 brelse(bp);
352 return (error);
353 }
354 if (entry_found) {
355 ep = (struct ext2fs_direct *)
356 ((char *)bp->b_data + (entryoffsetinblock & bmask));
357 /* foundentry: */
358 dp->i_ino = letoh32(ep->e2d_ino);
359 dp->i_reclen = letoh16(ep->e2d_reclen);
360 goto found;
361 }
362 }
363 /* notfound: */
364 /*
365 * If we started in the middle of the directory and failed
366 * to find our target, we must check the beginning as well.
367 */
368 if (numdirpasses == 2) {
369 numdirpasses--;
370 dp->i_offset = 0;
371 endsearch = dp->i_diroff;
372 goto searchloop;
373 }
374 if (bp != NULL)
375 brelse(bp);
376 /*
377 * If creating, and at end of pathname and current
378 * directory has not been removed, then can consider
379 * allowing file to be created.
380 */
381 if ((nameiop == CREATE || nameiop == RENAME) &&
382 (flags & ISLASTCN) && dp->i_e2fs_nlink != 0) {
383 /*
384 * Creation of files on a read-only mounted file system
385 * is pointless, so don't proceed any further.
386 */
387 if (vdp->v_mount->mnt_flag & MNT_RDONLY)
388 return (EROFS);
389 /*
390 * Access for write is interpreted as allowing
391 * creation of files in the directory.
392 */
393 if ((error = VOP_ACCESS(vdp, VWRITE, cred, cnp->cn_proc)) != 0)
394 return (error);
395 /*
396 * Return an indication of where the new directory
397 * entry should be put. If we didn't find a slot,
398 * then set dp->i_count to 0 indicating
399 * that the new slot belongs at the end of the
400 * directory. If we found a slot, then the new entry
401 * can be put in the range from dp->i_offset to
402 * dp->i_offset + dp->i_count.
403 */
404 if (ss.slotstatus == NONE) {
405 dp->i_offset = roundup(ext2fs_size(dp), dirblksize);
406 dp->i_count = 0;
407 enduseful = dp->i_offset;
408 } else {
409 dp->i_offset = ss.slotoffset;
410 dp->i_count = ss.slotsize;
411 if (enduseful < ss.slotoffset + ss.slotsize)
412 enduseful = ss.slotoffset + ss.slotsize;
413 }
414 dp->i_endoff = roundup(enduseful, dirblksize);
415 dp->i_flag |= IN_CHANGE | IN_UPDATE;
416 /*
417 * We return with the directory locked, so that
418 * the parameters we set up above will still be
419 * valid if we actually decide to do a direnter().
420 * We return ni_vp == NULL to indicate that the entry
421 * does not currently exist; we leave a pointer to
422 * the (locked) directory inode in ndp->ni_dvp.
423 * The pathname buffer is saved so that the name
424 * can be obtained later.
425 *
426 * NB - if the directory is unlocked, then this
427 * information cannot be used.
428 */
429 cnp->cn_flags |= SAVENAME;
430 if (!lockparent) {
431 VOP_UNLOCK(vdp);
432 cnp->cn_flags |= PDIRUNLOCK;
433 }
434 return (EJUSTRETURN);
435 }
436 /*
437 * Insert name into cache (as non-existent) if appropriate.
438 */
439 if ((cnp->cn_flags & MAKEENTRY) && nameiop != CREATE)
440 cache_enter(vdp, *vpp, cnp);
441 return (ENOENT);
442
443 found:
444 /*
445 * Check that directory length properly reflects presence
446 * of this entry.
447 */
448 if (entryoffsetinblock + EXT2FS_DIRSIZ(ep->e2d_namlen)
449 > ext2fs_size(dp)) {
450 ufs_dirbad(dp, dp->i_offset, "i_size too small");
451 error = ext2fs_setsize(dp,
452 entryoffsetinblock + EXT2FS_DIRSIZ(ep->e2d_namlen));
453 if (error) {
454 brelse(bp);
455 return(error);
456 }
457 dp->i_flag |= IN_CHANGE | IN_UPDATE;
458 }
459 brelse(bp);
460
461 /*
462 * Found component in pathname.
463 * If the final component of path name, save information
464 * in the cache as to where the entry was found.
465 */
466 if ((flags & ISLASTCN) && nameiop == LOOKUP)
467 dp->i_diroff = dp->i_offset &~ (dirblksize - 1);
468
469 /*
470 * If deleting, and at end of pathname, return
471 * parameters which can be used to remove file.
472 * If the wantparent flag isn't set, we return only
473 * the directory (in ndp->ni_dvp), otherwise we go
474 * on and lock the inode, being careful with ".".
475 */
476 if (nameiop == DELETE && (flags & ISLASTCN)) {
477 /*
478 * Write access to directory required to delete files.
479 */
480 if ((error = VOP_ACCESS(vdp, VWRITE, cred, cnp->cn_proc)) != 0)
481 return (error);
482 /*
483 * Return pointer to current entry in dp->i_offset,
484 * and distance past previous entry (if there
485 * is a previous entry in this block) in dp->i_count.
486 * Save directory inode pointer in ndp->ni_dvp for dirremove().
487 */
488 if ((dp->i_offset & (dirblksize - 1)) == 0)
489 dp->i_count = 0;
490 else
491 dp->i_count = dp->i_offset - prevoff;
492 if (dp->i_number == dp->i_ino) {
493 vref(vdp);
494 *vpp = vdp;
495 return (0);
496 }
497 if ((error = VFS_VGET(vdp->v_mount, dp->i_ino, &tdp)) != 0)
498 return (error);
499 /*
500 * If directory is "sticky", then user must own
501 * the directory, or the file in it, else she
502 * may not delete it (unless she's root). This
503 * implements append-only directories.
504 */
505 if ((dp->i_e2fs_mode & ISVTX) &&
506 cred->cr_uid != 0 &&
507 cred->cr_uid != dp->i_e2fs_uid &&
508 VTOI(tdp)->i_e2fs_uid != cred->cr_uid) {
509 vput(tdp);
510 return (EPERM);
511 }
512 *vpp = tdp;
513 if (!lockparent) {
514 VOP_UNLOCK(vdp);
515 cnp->cn_flags |= PDIRUNLOCK;
516 }
517 return (0);
518 }
519
520 /*
521 * If rewriting (RENAME), return the inode and the
522 * information required to rewrite the present directory
523 * Must get inode of directory entry to verify it's a
524 * regular file, or empty directory.
525 */
526 if (nameiop == RENAME && wantparent && (flags & ISLASTCN)) {
527 if ((error = VOP_ACCESS(vdp, VWRITE, cred, cnp->cn_proc)) != 0)
528 return (error);
529 /*
530 * Careful about locking second inode.
531 * This can only occur if the target is ".".
532 */
533 if (dp->i_number == dp->i_ino)
534 return (EISDIR);
535 if ((error = VFS_VGET(vdp->v_mount, dp->i_ino, &tdp)) != 0)
536 return (error);
537 *vpp = tdp;
538 cnp->cn_flags |= SAVENAME;
539 if (!lockparent) {
540 VOP_UNLOCK(vdp);
541 cnp->cn_flags |= PDIRUNLOCK;
542 }
543 return (0);
544 }
545
546 /*
547 * Step through the translation in the name. We do not `vput' the
548 * directory because we may need it again if a symbolic link
549 * is relative to the current directory. Instead we save it
550 * unlocked as "pdp". We must get the target inode before unlocking
551 * the directory to insure that the inode will not be removed
552 * before we get it. We prevent deadlock by always fetching
553 * inodes from the root, moving down the directory tree. Thus
554 * when following backward pointers ".." we must unlock the
555 * parent directory before getting the requested directory.
556 * There is a potential race condition here if both the current
557 * and parent directories are removed before the VFS_VGET for the
558 * inode associated with ".." returns. We hope that this occurs
559 * infrequently since we cannot avoid this race condition without
560 * implementing a sophisticated deadlock detection algorithm.
561 * Note also that this simple deadlock detection scheme will not
562 * work if the file system has any hard links other than ".."
563 * that point backwards in the directory structure.
564 */
565 pdp = vdp;
566 if (flags & ISDOTDOT) {
567 VOP_UNLOCK(pdp); /* race to get the inode */
568 cnp->cn_flags |= PDIRUNLOCK;
569 if ((error = VFS_VGET(vdp->v_mount, dp->i_ino, &tdp)) != 0) {
570 if (vn_lock(pdp, LK_EXCLUSIVE | LK_RETRY) == 0)
571 cnp->cn_flags &= ~PDIRUNLOCK;
572 return (error);
573 }
574 if (lockparent && (flags & ISLASTCN)) {
575 if ((error = vn_lock(pdp, LK_EXCLUSIVE)) != 0) {
576 vput(tdp);
577 return (error);
578 }
579 cnp->cn_flags &= ~PDIRUNLOCK;
580 }
581 *vpp = tdp;
582 } else if (dp->i_number == dp->i_ino) {
583 vref(vdp); /* we want ourself, ie "." */
584 *vpp = vdp;
585 } else {
586 if ((error = VFS_VGET(vdp->v_mount, dp->i_ino, &tdp)) != 0)
587 return (error);
588 if (!lockparent || !(flags & ISLASTCN)) {
589 VOP_UNLOCK(pdp);
590 cnp->cn_flags |= PDIRUNLOCK;
591 }
592 *vpp = tdp;
593 }
594
595 /*
596 * Insert name into cache if appropriate.
597 */
598 if (cnp->cn_flags & MAKEENTRY)
599 cache_enter(vdp, *vpp, cnp);
600 return (0);
601 }
602
603 int
ext2fs_search_dirblock(struct inode * ip,void * data,int * foundp,struct componentname * cnp,int * entryoffsetinblockp,doff_t * prevoffp,doff_t * endusefulp,struct ext2fs_searchslot * ssp)604 ext2fs_search_dirblock(struct inode *ip, void *data, int *foundp,
605 struct componentname *cnp, int *entryoffsetinblockp,
606 doff_t *prevoffp, doff_t *endusefulp, struct ext2fs_searchslot *ssp)
607 {
608 struct ext2fs_direct *ep, *lim;
609 struct vnode *vdp;
610 int offset = *entryoffsetinblockp;
611 int dirblksize = ip->i_e2fs->e2fs_bsize;
612 size_t namlen;
613
614 vdp = ITOV(ip);
615
616 lim = (struct ext2fs_direct *)
617 ((char *)data + dirblksize - EXT2FS_DIRSIZ(0));
618 ep = (struct ext2fs_direct *) ((char *)data + offset);
619
620 while (ep < lim) {
621 /*
622 * Full validation checks are slow, so we only check
623 * enough to insure forward progress through the
624 * directory. Complete checks can be run by patching
625 * "dirchk" to be true.
626 */
627 if (ep->e2d_reclen == 0 ||
628 (dirchk && ext2fs_dirbadentry(vdp, ep, offset))) {
629 int i;
630 ufs_dirbad(ip, ip->i_offset, "mangled entry");
631 i = dirblksize - (offset & (dirblksize - 1));
632 ip->i_offset += i;
633 offset += i;
634 continue;
635 }
636
637 /*
638 * If an appropriate sized slot has not yet been found,
639 * check to see if one is available. Also accumulate space
640 * in the current block so that we can determine if
641 * compaction is viable.
642 */
643 if (ssp->slotstatus != FOUND) {
644 int size = letoh16(ep->e2d_reclen);
645
646 if (ep->e2d_ino != 0)
647 size -= EXT2FS_DIRSIZ(ep->e2d_namlen);
648 if (size > 0) {
649 if (size >= ssp->slotneeded) {
650 ssp->slotstatus = FOUND;
651 ssp->slotoffset = ip->i_offset;
652 ssp->slotsize = letoh16(ep->e2d_reclen);
653 } else if (ssp->slotstatus == NONE) {
654 ssp->slotfreespace += size;
655 if (ssp->slotoffset == -1)
656 ssp->slotoffset = ip->i_offset;
657 if (ssp->slotfreespace >= ssp->slotneeded) {
658 ssp->slotstatus = COMPACT;
659 ssp->slotsize = ip->i_offset +
660 letoh16(ep->e2d_reclen) - ssp->slotoffset;
661 }
662 }
663 }
664 }
665
666 /*
667 * Check for a name match.
668 */
669 if (ep->e2d_ino) {
670 namlen = ep->e2d_namlen;
671 if (namlen == cnp->cn_namelen &&
672 !memcmp(cnp->cn_nameptr, ep->e2d_name, namlen)) {
673 /*
674 * Save directory entry's inode number and
675 * reclen in ndp->ni_ufs area, and release
676 * directory buffer.
677 */
678 *foundp = 1;
679 return (0);
680 }
681 }
682 *prevoffp = ip->i_offset;
683 ip->i_offset += letoh16(ep->e2d_reclen);
684 offset += letoh16(ep->e2d_reclen);
685 *entryoffsetinblockp = offset;
686 if (ep->e2d_ino)
687 *endusefulp = ip->i_offset;
688
689 /*
690 * Get pointer to the next entry.
691 */
692 ep = (struct ext2fs_direct *) ((char *)data + offset);
693 }
694
695 return (0);
696 }
697
698 /*
699 * Do consistency checking on a directory entry:
700 * record length must be multiple of 4
701 * entry must fit in rest of its dirblksize block
702 * record must be large enough to contain entry
703 * name is not longer than MAXNAMLEN
704 * name must be as long as advertised, and null terminated
705 */
706 /*
707 * changed so that it confirms to ext2fs_check_dir_entry
708 */
709 static int
ext2fs_dirbadentry(struct vnode * dp,struct ext2fs_direct * de,int entryoffsetinblock)710 ext2fs_dirbadentry(struct vnode *dp, struct ext2fs_direct *de,
711 int entryoffsetinblock)
712 {
713 int dirblksize = VTOI(dp)->i_e2fs->e2fs_bsize;
714 char *error_msg = NULL;
715 int reclen = letoh16(de->e2d_reclen);
716 int namlen = de->e2d_namlen;
717
718 if (reclen < EXT2FS_DIRSIZ(1)) /* e2d_namlen = 1 */
719 error_msg = "rec_len is smaller than minimal";
720 else if (reclen % 4 != 0)
721 error_msg = "rec_len % 4 != 0";
722 else if (reclen < EXT2FS_DIRSIZ(namlen))
723 error_msg = "reclen is too small for name_len";
724 else if (entryoffsetinblock + reclen > dirblksize)
725 error_msg = "directory entry across blocks";
726 else if (letoh32(de->e2d_ino) > VTOI(dp)->i_e2fs->e2fs.e2fs_icount)
727 error_msg = "inode out of bounds";
728
729 if (error_msg != NULL) {
730 printf("bad directory entry: %s\n"
731 "offset=%d, inode=%u, rec_len=%d, name_len=%d \n",
732 error_msg, entryoffsetinblock, letoh32(de->e2d_ino),
733 reclen, namlen);
734 panic(__func__);
735 }
736 return (0);
737 }
738
739 /*
740 * Write a directory entry after a call to namei, using the parameters
741 * that it left in nameidata. The argument ip is the inode which the new
742 * directory entry will refer to. Dvp is a pointer to the directory to
743 * be written, which was left locked by namei. Remaining parameters
744 * (dp->i_offset, dp->i_count) indicate how the space for the new
745 * entry is to be obtained.
746 */
747 int
ext2fs_direnter(struct inode * ip,struct vnode * dvp,struct componentname * cnp)748 ext2fs_direnter(struct inode *ip, struct vnode *dvp,
749 struct componentname *cnp)
750 {
751 struct ext2fs_direct *ep, *nep;
752 struct inode *dp;
753 struct buf *bp;
754 struct ext2fs_direct newdir;
755 struct iovec aiov;
756 struct uio auio;
757 u_int dsize;
758 int error, loc, newentrysize, spacefree;
759 char *dirbuf;
760 int dirblksize = ip->i_e2fs->e2fs_bsize;
761
762
763 #ifdef DIAGNOSTIC
764 if ((cnp->cn_flags & SAVENAME) == 0)
765 panic("direnter: missing name");
766 #endif
767 dp = VTOI(dvp);
768 newdir.e2d_ino = htole32(ip->i_number);
769 newdir.e2d_namlen = cnp->cn_namelen;
770 if (ip->i_e2fs->e2fs.e2fs_rev > E2FS_REV0 &&
771 (ip->i_e2fs->e2fs.e2fs_features_incompat & EXT2F_INCOMPAT_FTYPE)) {
772 newdir.e2d_type = inot2ext2dt(IFTODT(ip->i_e2fs_mode));
773 } else {
774 newdir.e2d_type = 0;
775 };
776 memcpy(newdir.e2d_name, cnp->cn_nameptr, (unsigned)cnp->cn_namelen + 1);
777 newentrysize = EXT2FS_DIRSIZ(cnp->cn_namelen);
778 if (dp->i_count == 0) {
779 /*
780 * If dp->i_count is 0, then namei could find no
781 * space in the directory. Here, dp->i_offset will
782 * be on a directory block boundary and we will write the
783 * new entry into a fresh block.
784 */
785 if (dp->i_offset & (dirblksize - 1))
786 panic("ext2fs_direnter: newblk");
787 auio.uio_offset = dp->i_offset;
788 newdir.e2d_reclen = htole16(dirblksize);
789 auio.uio_resid = newentrysize;
790 aiov.iov_len = newentrysize;
791 aiov.iov_base = (caddr_t)&newdir;
792 auio.uio_iov = &aiov;
793 auio.uio_iovcnt = 1;
794 auio.uio_rw = UIO_WRITE;
795 auio.uio_segflg = UIO_SYSSPACE;
796 auio.uio_procp = NULL;
797 error = VOP_WRITE(dvp, &auio, IO_SYNC, cnp->cn_cred);
798 if (dirblksize >
799 VFSTOUFS(dvp->v_mount)->um_mountp->mnt_stat.f_bsize)
800 /* XXX should grow with balloc() */
801 panic("ext2fs_direnter: frag size");
802 else if (!error) {
803 error = ext2fs_setsize(dp,
804 roundup(ext2fs_size(dp), dirblksize));
805 if (error)
806 return (error);
807 dp->i_flag |= IN_CHANGE;
808 }
809 return (error);
810 }
811
812 /*
813 * If dp->i_count is non-zero, then namei found space
814 * for the new entry in the range dp->i_offset to
815 * dp->i_offset + dp->i_count in the directory.
816 * To use this space, we may have to compact the entries located
817 * there, by copying them together towards the beginning of the
818 * block, leaving the free space in one usable chunk at the end.
819 */
820
821 /*
822 * Get the block containing the space for the new directory entry.
823 */
824 if ((error = ext2fs_bufatoff(dp, (off_t)dp->i_offset, &dirbuf, &bp))
825 != 0)
826 return (error);
827 /*
828 * Find space for the new entry. In the simple case, the entry at
829 * offset base will have the space. If it does not, then namei
830 * arranged that compacting the region dp->i_offset to
831 * dp->i_offset + dp->i_count would yield the
832 * space.
833 */
834 ep = (struct ext2fs_direct *)dirbuf;
835 dsize = EXT2FS_DIRSIZ(ep->e2d_namlen);
836 spacefree = letoh16(ep->e2d_reclen) - dsize;
837 for (loc = letoh16(ep->e2d_reclen); loc < dp->i_count; ) {
838 nep = (struct ext2fs_direct *)(dirbuf + loc);
839 if (ep->e2d_ino) {
840 /* trim the existing slot */
841 ep->e2d_reclen = htole16(dsize);
842 ep = (struct ext2fs_direct *)((char *)ep + dsize);
843 } else {
844 /* overwrite; nothing there; header is ours */
845 spacefree += dsize;
846 }
847 dsize = EXT2FS_DIRSIZ(nep->e2d_namlen);
848 spacefree += letoh16(nep->e2d_reclen) - dsize;
849 loc += letoh16(nep->e2d_reclen);
850 memcpy(ep, nep, dsize);
851 }
852 /*
853 * Update the pointer fields in the previous entry (if any),
854 * copy in the new entry, and write out the block.
855 */
856 if (ep->e2d_ino == 0) {
857 #ifdef DIAGNOSTIC
858 if (spacefree + dsize < newentrysize)
859 panic("ext2fs_direnter: compact1");
860 #endif
861 newdir.e2d_reclen = htole16(spacefree + dsize);
862 } else {
863 #ifdef DIAGNOSTIC
864 if (spacefree < newentrysize) {
865 printf("ext2fs_direnter: compact2 %u %u",
866 (u_int)spacefree, (u_int)newentrysize);
867 panic("ext2fs_direnter: compact2");
868 }
869 #endif
870 newdir.e2d_reclen = htole16(spacefree);
871 ep->e2d_reclen = htole16(dsize);
872 ep = (struct ext2fs_direct *)((char *)ep + dsize);
873 }
874 memcpy(ep, &newdir, newentrysize);
875 error = VOP_BWRITE(bp);
876 dp->i_flag |= IN_CHANGE | IN_UPDATE;
877 if (!error && dp->i_endoff && dp->i_endoff < ext2fs_size(dp))
878 error = ext2fs_truncate(dp, (off_t)dp->i_endoff, IO_SYNC,
879 cnp->cn_cred);
880 return (error);
881 }
882
883 /*
884 * Remove a directory entry after a call to namei, using
885 * the parameters which it left in nameidata. The entry
886 * dp->i_offset contains the offset into the directory of the
887 * entry to be eliminated. The dp->i_count field contains the
888 * size of the previous record in the directory. If this
889 * is 0, the first entry is being deleted, so we need only
890 * zero the inode number to mark the entry as free. If the
891 * entry is not the first in the directory, we must reclaim
892 * the space of the now empty record by adding the record size
893 * to the size of the previous entry.
894 */
895 int
ext2fs_dirremove(struct vnode * dvp,struct componentname * cnp)896 ext2fs_dirremove(struct vnode *dvp, struct componentname *cnp)
897 {
898 struct inode *dp;
899 struct ext2fs_direct *ep;
900 struct buf *bp;
901 int error;
902
903 dp = VTOI(dvp);
904 if (dp->i_count == 0) {
905 /*
906 * First entry in block: set d_ino to zero.
907 */
908 error = ext2fs_bufatoff(dp, (off_t)dp->i_offset, (char **)&ep,
909 &bp);
910 if (error != 0)
911 return (error);
912 ep->e2d_ino = 0;
913 error = VOP_BWRITE(bp);
914 dp->i_flag |= IN_CHANGE | IN_UPDATE;
915 return (error);
916 }
917 /*
918 * Collapse new free space into previous entry.
919 */
920 error = ext2fs_bufatoff(dp, (off_t)(dp->i_offset - dp->i_count),
921 (char **)&ep, &bp);
922 if (error != 0)
923 return (error);
924 ep->e2d_reclen = htole16(letoh16(ep->e2d_reclen) + dp->i_reclen);
925 error = VOP_BWRITE(bp);
926 dp->i_flag |= IN_CHANGE | IN_UPDATE;
927 return (error);
928 }
929
930 /*
931 * Rewrite an existing directory entry to point at the inode
932 * supplied. The parameters describing the directory entry are
933 * set up by a call to namei.
934 */
935 int
ext2fs_dirrewrite(struct inode * dp,struct inode * ip,struct componentname * cnp)936 ext2fs_dirrewrite(struct inode *dp, struct inode *ip,
937 struct componentname *cnp)
938 {
939 struct buf *bp;
940 struct ext2fs_direct *ep;
941 int error;
942
943 error = ext2fs_bufatoff(dp, (off_t)dp->i_offset, (char **)&ep, &bp);
944 if (error != 0)
945 return (error);
946 ep->e2d_ino = htole32(ip->i_number);
947 if (ip->i_e2fs->e2fs.e2fs_rev > E2FS_REV0 &&
948 (ip->i_e2fs->e2fs.e2fs_features_incompat & EXT2F_INCOMPAT_FTYPE)) {
949 ep->e2d_type = inot2ext2dt(IFTODT(ip->i_e2fs_mode));
950 } else {
951 ep->e2d_type = 0;
952 }
953 error = VOP_BWRITE(bp);
954 dp->i_flag |= IN_CHANGE | IN_UPDATE;
955 return (error);
956 }
957
958 /*
959 * Check if a directory is empty or not.
960 * Inode supplied must be locked.
961 *
962 * Using a struct dirtemplate here is not precisely
963 * what we want, but better than using a struct ext2fs_direct.
964 *
965 * NB: does not handle corrupted directories.
966 */
967 int
ext2fs_dirempty(struct inode * ip,ufsino_t parentino,struct ucred * cred)968 ext2fs_dirempty(struct inode *ip, ufsino_t parentino, struct ucred *cred)
969 {
970 off_t off;
971 struct ext2fs_dirtemplate dbuf;
972 struct ext2fs_direct *dp = (struct ext2fs_direct *)&dbuf;
973 int error, namlen;
974 size_t count;
975
976 #define MINDIRSIZ (sizeof (struct ext2fs_dirtemplate) / 2)
977
978 for (off = 0; off < ext2fs_size(ip); off += letoh16(dp->e2d_reclen)) {
979 error = vn_rdwr(UIO_READ, ITOV(ip), (caddr_t)dp, MINDIRSIZ, off,
980 UIO_SYSSPACE, IO_NODELOCKED, cred, &count, curproc);
981 /*
982 * Since we read MINDIRSIZ, residual must
983 * be 0 unless we're at end of file.
984 */
985 if (error || count != 0)
986 return (0);
987 /* avoid infinite loops */
988 if (dp->e2d_reclen == 0)
989 return (0);
990 /* skip empty entries */
991 if (dp->e2d_ino == 0)
992 continue;
993 /* accept only "." and ".." */
994 namlen = dp->e2d_namlen;
995 if (namlen > 2)
996 return (0);
997 if (dp->e2d_name[0] != '.')
998 return (0);
999 /*
1000 * At this point namlen must be 1 or 2.
1001 * 1 implies ".", 2 implies ".." if second
1002 * char is also "."
1003 */
1004 if (namlen == 1)
1005 continue;
1006 if (dp->e2d_name[1] == '.' && letoh32(dp->e2d_ino) == parentino)
1007 continue;
1008 return (0);
1009 }
1010 return (1);
1011 }
1012
1013 /*
1014 * Check if source directory is in the path of the target directory.
1015 * Target is supplied locked, source is unlocked.
1016 * The target is always vput before returning.
1017 */
1018 int
ext2fs_checkpath(struct inode * source,struct inode * target,struct ucred * cred)1019 ext2fs_checkpath(struct inode *source, struct inode *target,
1020 struct ucred *cred)
1021 {
1022 struct vnode *vp;
1023 int error, rootino, namlen;
1024 struct ext2fs_dirtemplate dirbuf;
1025 u_int32_t ino;
1026
1027 vp = ITOV(target);
1028 if (target->i_number == source->i_number) {
1029 error = EEXIST;
1030 goto out;
1031 }
1032 rootino = ROOTINO;
1033 error = 0;
1034 if (target->i_number == rootino)
1035 goto out;
1036
1037 for (;;) {
1038 if (vp->v_type != VDIR) {
1039 error = ENOTDIR;
1040 break;
1041 }
1042 error = vn_rdwr(UIO_READ, vp, (caddr_t)&dirbuf,
1043 sizeof (struct ext2fs_dirtemplate), (off_t)0,
1044 UIO_SYSSPACE, IO_NODELOCKED, cred, NULL,
1045 curproc);
1046 if (error != 0)
1047 break;
1048 namlen = dirbuf.dotdot_namlen;
1049 if (namlen != 2 ||
1050 dirbuf.dotdot_name[0] != '.' ||
1051 dirbuf.dotdot_name[1] != '.') {
1052 error = ENOTDIR;
1053 break;
1054 }
1055 ino = letoh32(dirbuf.dotdot_ino);
1056 if (ino == source->i_number) {
1057 error = EINVAL;
1058 break;
1059 }
1060 if (ino == rootino)
1061 break;
1062 vput(vp);
1063 error = VFS_VGET(vp->v_mount, ino, &vp);
1064 if (error != 0) {
1065 vp = NULL;
1066 break;
1067 }
1068 }
1069
1070 out:
1071 if (error == ENOTDIR) {
1072 printf("checkpath: .. not a directory\n");
1073 panic("checkpath");
1074 }
1075 if (vp != NULL)
1076 vput(vp);
1077 return (error);
1078 }
1079