1 | /* $NetBSD: ext2fs_lookup.c,v 1.88 2016/08/23 06:40:25 christos Exp $ */ |
2 | |
3 | /* |
4 | * Modified for NetBSD 1.2E |
5 | * May 1997, Manuel Bouyer |
6 | * Laboratoire d'informatique de Paris VI |
7 | */ |
8 | /* |
9 | * modified for Lites 1.1 |
10 | * |
11 | * Aug 1995, Godmar Back (gback@cs.utah.edu) |
12 | * University of Utah, Department of Computer Science |
13 | */ |
14 | /* |
15 | * Copyright (c) 1989, 1993 |
16 | * The Regents of the University of California. All rights reserved. |
17 | * (c) UNIX System Laboratories, Inc. |
18 | * All or some portions of this file are derived from material licensed |
19 | * to the University of California by American Telephone and Telegraph |
20 | * Co. or Unix System Laboratories, Inc. and are reproduced herein with |
21 | * the permission of UNIX System Laboratories, Inc. |
22 | * |
23 | * Redistribution and use in source and binary forms, with or without |
24 | * modification, are permitted provided that the following conditions |
25 | * are met: |
26 | * 1. Redistributions of source code must retain the above copyright |
27 | * notice, this list of conditions and the following disclaimer. |
28 | * 2. Redistributions in binary form must reproduce the above copyright |
29 | * notice, this list of conditions and the following disclaimer in the |
30 | * documentation and/or other materials provided with the distribution. |
31 | * 3. Neither the name of the University nor the names of its contributors |
32 | * may be used to endorse or promote products derived from this software |
33 | * without specific prior written permission. |
34 | * |
35 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
36 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
37 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
38 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
39 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
40 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
41 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
42 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
43 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
44 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
45 | * SUCH DAMAGE. |
46 | * |
47 | * @(#)ufs_lookup.c 8.6 (Berkeley) 4/1/94 |
48 | */ |
49 | |
50 | #include <sys/cdefs.h> |
51 | __KERNEL_RCSID(0, "$NetBSD: ext2fs_lookup.c,v 1.88 2016/08/23 06:40:25 christos Exp $" ); |
52 | |
53 | #include <sys/param.h> |
54 | #include <sys/systm.h> |
55 | #include <sys/namei.h> |
56 | #include <sys/buf.h> |
57 | #include <sys/file.h> |
58 | #include <sys/mount.h> |
59 | #include <sys/vnode.h> |
60 | #include <sys/kmem.h> |
61 | #include <sys/malloc.h> |
62 | #include <sys/dirent.h> |
63 | #include <sys/kauth.h> |
64 | #include <sys/proc.h> |
65 | |
66 | #include <ufs/ufs/inode.h> |
67 | #include <ufs/ufs/ufsmount.h> |
68 | #include <ufs/ufs/ufs_extern.h> |
69 | |
70 | #include <ufs/ext2fs/ext2fs_extern.h> |
71 | #include <ufs/ext2fs/ext2fs_dir.h> |
72 | #include <ufs/ext2fs/ext2fs.h> |
73 | #include <ufs/ext2fs/ext2fs_htree.h> |
74 | |
75 | #include <miscfs/genfs/genfs.h> |
76 | |
77 | extern int dirchk; |
78 | |
79 | static void ext2fs_dirconv2ffs(struct m_ext2fs *fs, |
80 | struct ext2fs_direct *e2dir, |
81 | struct dirent *ffsdir); |
82 | static int ext2fs_dirbadentry(struct vnode *dp, |
83 | struct ext2fs_direct *de, |
84 | int entryoffsetinblock); |
85 | |
86 | /* |
87 | * the problem that is tackled below is the fact that FFS |
88 | * includes the terminating zero on disk while EXT2FS doesn't |
89 | * this implies that we need to introduce some padding. |
90 | * For instance, a filename "sbin" has normally a reclen 12 |
91 | * in EXT2, but 16 in FFS. |
92 | * This reminds me of that Pepsi commercial: 'Kid saved a lousy nine cents...' |
93 | * If it wasn't for that, the complete ufs code for directories would |
94 | * have worked w/o changes (except for the difference in DIRBLKSIZ) |
95 | */ |
96 | static void |
97 | ext2fs_dirconv2ffs(struct m_ext2fs *fs, struct ext2fs_direct *e2dir, struct dirent *ffsdir) |
98 | { |
99 | memset(ffsdir, 0, sizeof(struct dirent)); |
100 | ffsdir->d_fileno = fs2h32(e2dir->e2d_ino); |
101 | ffsdir->d_namlen = e2dir->e2d_namlen; |
102 | |
103 | if (EXT2F_HAS_INCOMPAT_FEATURE(fs, EXT2F_INCOMPAT_FTYPE)) |
104 | ffsdir->d_type = ext2dt2dt(e2dir->e2d_type); |
105 | else |
106 | ffsdir->d_type = DT_UNKNOWN; |
107 | |
108 | #ifdef DIAGNOSTIC |
109 | #if MAXNAMLEN < E2FS_MAXNAMLEN |
110 | /* |
111 | * we should handle this more gracefully ! |
112 | */ |
113 | if (e2dir->e2d_namlen > MAXNAMLEN) |
114 | panic("ext2fs: e2dir->e2d_namlen" ); |
115 | #endif |
116 | #endif |
117 | strncpy(ffsdir->d_name, e2dir->e2d_name, ffsdir->d_namlen); |
118 | |
119 | /* Godmar thinks: since e2dir->e2d_reclen can be big and means |
120 | nothing anyway, we compute our own reclen according to what |
121 | we think is right |
122 | */ |
123 | ffsdir->d_reclen = _DIRENT_SIZE(ffsdir); |
124 | } |
125 | |
126 | static int |
127 | ext2fs_is_dot_entry(struct componentname *cnp) |
128 | { |
129 | return cnp->cn_namelen <= 2 && cnp->cn_nameptr[0] == '.' && |
130 | (cnp->cn_nameptr[1] == '.' || cnp->cn_nameptr[1] == '\0'); |
131 | } |
132 | |
133 | /* |
134 | * Vnode op for reading directories. |
135 | * |
136 | * Convert the on-disk entries to <sys/dirent.h> entries. |
137 | * the problem is that the conversion will blow up some entries by four bytes, |
138 | * so it can't be done in place. This is too bad. Right now the conversion is |
139 | * done entry by entry, the converted entry is sent via uiomove. |
140 | * |
141 | * XXX allocate a buffer, convert as many entries as possible, then send |
142 | * the whole buffer to uiomove |
143 | */ |
144 | int |
145 | ext2fs_readdir(void *v) |
146 | { |
147 | struct vop_readdir_args /* { |
148 | struct vnode *a_vp; |
149 | struct uio *a_uio; |
150 | kauth_cred_t a_cred; |
151 | int **a_eofflag; |
152 | off_t **a_cookies; |
153 | int ncookies; |
154 | } */ *ap = v; |
155 | struct uio *uio = ap->a_uio; |
156 | int error; |
157 | size_t e2fs_count, readcnt; |
158 | struct vnode *vp = ap->a_vp; |
159 | struct m_ext2fs *fs = VTOI(vp)->i_e2fs; |
160 | |
161 | struct ext2fs_direct *dp; |
162 | struct dirent *dstd; |
163 | struct uio auio; |
164 | struct iovec aiov; |
165 | void *dirbuf; |
166 | off_t off = uio->uio_offset; |
167 | off_t *cookies = NULL; |
168 | int nc = 0, ncookies = 0; |
169 | int e2d_reclen; |
170 | |
171 | if (vp->v_type != VDIR) |
172 | return ENOTDIR; |
173 | |
174 | e2fs_count = uio->uio_resid; |
175 | /* Make sure we don't return partial entries. */ |
176 | e2fs_count -= (uio->uio_offset + e2fs_count) & (fs->e2fs_bsize -1); |
177 | if (e2fs_count <= 0) |
178 | return EINVAL; |
179 | |
180 | auio = *uio; |
181 | auio.uio_iov = &aiov; |
182 | auio.uio_iovcnt = 1; |
183 | aiov.iov_len = e2fs_count; |
184 | auio.uio_resid = e2fs_count; |
185 | UIO_SETUP_SYSSPACE(&auio); |
186 | dirbuf = kmem_alloc(e2fs_count, KM_SLEEP); |
187 | dstd = kmem_zalloc(sizeof(struct dirent), KM_SLEEP); |
188 | if (ap->a_ncookies) { |
189 | nc = e2fs_count / _DIRENT_MINSIZE((struct dirent *)0); |
190 | ncookies = nc; |
191 | cookies = malloc(sizeof (off_t) * ncookies, M_TEMP, M_WAITOK); |
192 | *ap->a_cookies = cookies; |
193 | } |
194 | aiov.iov_base = dirbuf; |
195 | |
196 | error = UFS_BUFRD(ap->a_vp, &auio, 0, ap->a_cred); |
197 | if (error == 0) { |
198 | readcnt = e2fs_count - auio.uio_resid; |
199 | for (dp = (struct ext2fs_direct *)dirbuf; |
200 | (char *)dp < (char *)dirbuf + readcnt;) { |
201 | e2d_reclen = fs2h16(dp->e2d_reclen); |
202 | if (e2d_reclen == 0) { |
203 | error = EIO; |
204 | break; |
205 | } |
206 | ext2fs_dirconv2ffs(fs, dp, dstd); |
207 | if(dstd->d_reclen > uio->uio_resid) { |
208 | break; |
209 | } |
210 | error = uiomove(dstd, dstd->d_reclen, uio); |
211 | if (error != 0) { |
212 | break; |
213 | } |
214 | off = off + e2d_reclen; |
215 | if (cookies != NULL) { |
216 | *cookies++ = off; |
217 | if (--ncookies <= 0){ |
218 | break; /* out of cookies */ |
219 | } |
220 | } |
221 | /* advance dp */ |
222 | dp = (struct ext2fs_direct *) ((char *)dp + e2d_reclen); |
223 | } |
224 | /* we need to correct uio_offset */ |
225 | uio->uio_offset = off; |
226 | } |
227 | kmem_free(dirbuf, e2fs_count); |
228 | kmem_free(dstd, sizeof(*dstd)); |
229 | *ap->a_eofflag = ext2fs_size(VTOI(ap->a_vp)) <= uio->uio_offset; |
230 | if (ap->a_ncookies) { |
231 | if (error) { |
232 | free(*ap->a_cookies, M_TEMP); |
233 | *ap->a_ncookies = 0; |
234 | *ap->a_cookies = NULL; |
235 | } else |
236 | *ap->a_ncookies = nc - ncookies; |
237 | } |
238 | return error; |
239 | } |
240 | |
241 | /* |
242 | * Convert a component of a pathname into a pointer to a locked inode. |
243 | * This is a very central and rather complicated routine. |
244 | * If the file system is not maintained in a strict tree hierarchy, |
245 | * this can result in a deadlock situation (see comments in code below). |
246 | * |
247 | * The cnp->cn_nameiop argument is LOOKUP, CREATE, RENAME, or DELETE depending |
248 | * on whether the name is to be looked up, created, renamed, or deleted. |
249 | * When CREATE, RENAME, or DELETE is specified, information usable in |
250 | * creating, renaming, or deleting a directory entry may be calculated. |
251 | * If flag has LOCKPARENT or'ed into it and the target of the pathname |
252 | * exists, lookup returns both the target and its parent directory locked. |
253 | * When creating or renaming and LOCKPARENT is specified, the target may |
254 | * not be ".". When deleting and LOCKPARENT is specified, the target may |
255 | * be "."., but the caller must check to ensure it does an vrele and vput |
256 | * instead of two vputs. |
257 | * |
258 | * Overall outline of ext2fs_lookup: |
259 | * |
260 | * check accessibility of directory |
261 | * look for name in cache, if found, then if at end of path |
262 | * and deleting or creating, drop it, else return name |
263 | * search for name in directory, to found or notfound |
264 | * notfound: |
265 | * if creating, return locked directory, leaving info on available slots |
266 | * else return error |
267 | * found: |
268 | * if at end of path and deleting, return information to allow delete |
269 | * if at end of path and rewriting (RENAME and LOCKPARENT), lock target |
270 | * inode and return info to allow rewrite |
271 | * if not at end, add name to cache; if at end and neither creating |
272 | * nor deleting, add name to cache |
273 | */ |
274 | int |
275 | ext2fs_lookup(void *v) |
276 | { |
277 | struct vop_lookup_v2_args /* { |
278 | struct vnode *a_dvp; |
279 | struct vnode **a_vpp; |
280 | struct componentname *a_cnp; |
281 | } */ *ap = v; |
282 | struct vnode *vdp = ap->a_dvp; /* vnode for directory being searched */ |
283 | struct inode *dp = VTOI(vdp); /* inode for directory being searched */ |
284 | struct buf *bp; /* a buffer of directory entries */ |
285 | struct ext2fs_direct *ep; /* the current directory entry */ |
286 | int entryoffsetinblock; /* offset of ep in bp's buffer */ |
287 | enum ext2fs_slotstatus slotstatus; |
288 | doff_t slotoffset; /* offset of area with free space */ |
289 | int slotsize; /* size of area at slotoffset */ |
290 | int slotfreespace; /* amount of space free in slot */ |
291 | int slotneeded; /* size of the entry we're seeking */ |
292 | int numdirpasses; /* strategy for directory search */ |
293 | doff_t endsearch; /* offset to end directory search */ |
294 | doff_t prevoff; /* prev entry dp->i_offset */ |
295 | struct vnode *tdp; /* returned by vcache_get */ |
296 | doff_t enduseful; /* pointer past last used dir slot */ |
297 | u_long bmask; /* block offset mask */ |
298 | int namlen, error; |
299 | struct vnode **vpp = ap->a_vpp; |
300 | struct componentname *cnp = ap->a_cnp; |
301 | kauth_cred_t cred = cnp->cn_cred; |
302 | int flags; |
303 | int nameiop = cnp->cn_nameiop; |
304 | struct ufsmount *ump = dp->i_ump; |
305 | int dirblksiz = ump->um_dirblksiz; |
306 | ino_t foundino; |
307 | struct ufs_lookup_results *results; |
308 | |
309 | flags = cnp->cn_flags; |
310 | |
311 | bp = NULL; |
312 | slotoffset = -1; |
313 | *vpp = NULL; |
314 | |
315 | /* |
316 | * Produce the auxiliary lookup results into i_crap. Increment |
317 | * its serial number so elsewhere we can tell if we're using |
318 | * stale results. This should not be done this way. XXX. |
319 | */ |
320 | results = &dp->i_crap; |
321 | dp->i_crapcounter++; |
322 | |
323 | /* |
324 | * Check accessiblity of directory. |
325 | */ |
326 | if ((error = VOP_ACCESS(vdp, VEXEC, cred)) != 0) |
327 | return error; |
328 | |
329 | if ((flags & ISLASTCN) && (vdp->v_mount->mnt_flag & MNT_RDONLY) && |
330 | (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME)) |
331 | return EROFS; |
332 | |
333 | /* |
334 | * We now have a segment name to search for, and a directory to search. |
335 | * |
336 | * Before tediously performing a linear scan of the directory, |
337 | * check the name cache to see if the directory/name pair |
338 | * we are looking for is known already. |
339 | */ |
340 | if (cache_lookup(vdp, cnp->cn_nameptr, cnp->cn_namelen, |
341 | cnp->cn_nameiop, cnp->cn_flags, NULL, vpp)) { |
342 | return *vpp == NULLVP ? ENOENT : 0; |
343 | } |
344 | |
345 | /* |
346 | * Suppress search for slots unless creating |
347 | * file and at end of pathname, in which case |
348 | * we watch for a place to put the new file in |
349 | * case it doesn't already exist. |
350 | */ |
351 | slotstatus = FOUND; |
352 | slotfreespace = slotsize = slotneeded = 0; |
353 | if ((nameiop == CREATE || nameiop == RENAME) && |
354 | (flags & ISLASTCN)) { |
355 | slotstatus = NONE; |
356 | slotneeded = EXT2FS_DIRSIZ(cnp->cn_namelen); |
357 | } |
358 | |
359 | /* |
360 | * If there is cached information on a previous search of |
361 | * this directory, pick up where we last left off. |
362 | * We cache only lookups as these are the most common |
363 | * and have the greatest payoff. Caching CREATE has little |
364 | * benefit as it usually must search the entire directory |
365 | * to determine that the entry does not exist. Caching the |
366 | * location of the last DELETE or RENAME has not reduced |
367 | * profiling time and hence has been removed in the interest |
368 | * of simplicity. |
369 | */ |
370 | bmask = vdp->v_mount->mnt_stat.f_iosize - 1; |
371 | if (nameiop != LOOKUP || results->ulr_diroff == 0 || |
372 | results->ulr_diroff >= ext2fs_size(dp)) { |
373 | entryoffsetinblock = 0; |
374 | results->ulr_offset = 0; |
375 | numdirpasses = 1; |
376 | } else { |
377 | results->ulr_offset = results->ulr_diroff; |
378 | if ((entryoffsetinblock = results->ulr_offset & bmask) && |
379 | (error = ext2fs_blkatoff(vdp, (off_t)results->ulr_offset, NULL, &bp))) |
380 | return error; |
381 | numdirpasses = 2; |
382 | namecache_count_2passes(); |
383 | } |
384 | prevoff = results->ulr_offset; |
385 | endsearch = roundup(ext2fs_size(dp), dirblksiz); |
386 | enduseful = 0; |
387 | /* |
388 | * Try to lookup dir entry using htree directory index. |
389 | * |
390 | * If we got an error or we want to find '.' or '..' entry, |
391 | * we will fall back to linear search. |
392 | */ |
393 | if (!ext2fs_is_dot_entry(cnp) && ext2fs_htree_has_idx(dp)) { |
394 | doff_t i_offset; /* cached i_offset value */ |
395 | struct ext2fs_searchslot ss; |
396 | numdirpasses = 1; |
397 | entryoffsetinblock = 0; |
398 | |
399 | int htree_lookup_ret = ext2fs_htree_lookup(dp, cnp->cn_nameptr, |
400 | cnp->cn_namelen, &bp, &entryoffsetinblock, &i_offset, |
401 | &prevoff, &enduseful, &ss); |
402 | switch (htree_lookup_ret) { |
403 | case 0: |
404 | ep = (void *)((char *)bp->b_data + (i_offset & bmask)); |
405 | foundino = ep->e2d_ino; |
406 | goto found; |
407 | case ENOENT: |
408 | i_offset = roundup2(dp->i_size, dp->i_e2fs->e2fs_bsize); |
409 | goto notfound; |
410 | default: |
411 | /* |
412 | * Something failed; just fallback to do a linear |
413 | * search. |
414 | */ |
415 | break; |
416 | } |
417 | } |
418 | |
419 | searchloop: |
420 | while (results->ulr_offset < endsearch) { |
421 | if (curcpu()->ci_schedstate.spc_flags & SPCF_SHOULDYIELD) |
422 | preempt(); |
423 | /* |
424 | * If necessary, get the next directory block. |
425 | */ |
426 | if ((results->ulr_offset & bmask) == 0) { |
427 | if (bp != NULL) |
428 | brelse(bp, 0); |
429 | error = ext2fs_blkatoff(vdp, (off_t)results->ulr_offset, |
430 | NULL, &bp); |
431 | if (error != 0) |
432 | return error; |
433 | entryoffsetinblock = 0; |
434 | } |
435 | /* |
436 | * If still looking for a slot, and at a dirblksize |
437 | * boundary, have to start looking for free space again. |
438 | */ |
439 | if (slotstatus == NONE && |
440 | (entryoffsetinblock & (dirblksiz - 1)) == 0) { |
441 | slotoffset = -1; |
442 | slotfreespace = 0; |
443 | } |
444 | /* |
445 | * Get pointer to next entry. |
446 | * Full validation checks are slow, so we only check |
447 | * enough to insure forward progress through the |
448 | * directory. Complete checks can be run by patching |
449 | * "dirchk" to be true. |
450 | */ |
451 | KASSERT(bp != NULL); |
452 | ep = (struct ext2fs_direct *) |
453 | ((char *)bp->b_data + entryoffsetinblock); |
454 | if (ep->e2d_reclen == 0 || |
455 | (dirchk && |
456 | ext2fs_dirbadentry(vdp, ep, entryoffsetinblock))) { |
457 | int i; |
458 | |
459 | ufs_dirbad(dp, results->ulr_offset, "mangled entry" ); |
460 | i = dirblksiz - (entryoffsetinblock & (dirblksiz - 1)); |
461 | results->ulr_offset += i; |
462 | entryoffsetinblock += i; |
463 | continue; |
464 | } |
465 | |
466 | /* |
467 | * If an appropriate sized slot has not yet been found, |
468 | * check to see if one is available. Also accumulate space |
469 | * in the current block so that we can determine if |
470 | * compaction is viable. |
471 | */ |
472 | if (slotstatus != FOUND) { |
473 | int size = fs2h16(ep->e2d_reclen); |
474 | |
475 | if (ep->e2d_ino != 0) |
476 | size -= EXT2FS_DIRSIZ(ep->e2d_namlen); |
477 | if (size > 0) { |
478 | if (size >= slotneeded) { |
479 | slotstatus = FOUND; |
480 | slotoffset = results->ulr_offset; |
481 | slotsize = fs2h16(ep->e2d_reclen); |
482 | } else if (slotstatus == NONE) { |
483 | slotfreespace += size; |
484 | if (slotoffset == -1) |
485 | slotoffset = results->ulr_offset; |
486 | if (slotfreespace >= slotneeded) { |
487 | slotstatus = COMPACT; |
488 | slotsize = results->ulr_offset + |
489 | fs2h16(ep->e2d_reclen) - |
490 | slotoffset; |
491 | } |
492 | } |
493 | } |
494 | } |
495 | |
496 | /* |
497 | * Check for a name match. |
498 | */ |
499 | if (ep->e2d_ino) { |
500 | namlen = ep->e2d_namlen; |
501 | if (namlen == cnp->cn_namelen && |
502 | !memcmp(cnp->cn_nameptr, ep->e2d_name, |
503 | (unsigned)namlen)) { |
504 | /* |
505 | * Save directory entry's inode number and |
506 | * reclen in ndp->ni_ufs area, and release |
507 | * directory buffer. |
508 | */ |
509 | foundino = fs2h32(ep->e2d_ino); |
510 | results->ulr_reclen = fs2h16(ep->e2d_reclen); |
511 | goto found; |
512 | } |
513 | } |
514 | prevoff = results->ulr_offset; |
515 | results->ulr_offset += fs2h16(ep->e2d_reclen); |
516 | entryoffsetinblock += fs2h16(ep->e2d_reclen); |
517 | if (ep->e2d_ino) |
518 | enduseful = results->ulr_offset; |
519 | } |
520 | notfound: |
521 | /* |
522 | * If we started in the middle of the directory and failed |
523 | * to find our target, we must check the beginning as well. |
524 | */ |
525 | if (numdirpasses == 2) { |
526 | numdirpasses--; |
527 | results->ulr_offset = 0; |
528 | endsearch = results->ulr_diroff; |
529 | goto searchloop; |
530 | } |
531 | if (bp != NULL) |
532 | brelse(bp, 0); |
533 | /* |
534 | * If creating, and at end of pathname and current |
535 | * directory has not been removed, then can consider |
536 | * allowing file to be created. |
537 | */ |
538 | if ((nameiop == CREATE || nameiop == RENAME) && |
539 | (flags & ISLASTCN) && dp->i_e2fs_nlink != 0) { |
540 | /* |
541 | * Access for write is interpreted as allowing |
542 | * creation of files in the directory. |
543 | */ |
544 | error = VOP_ACCESS(vdp, VWRITE, cred); |
545 | if (error) |
546 | return error; |
547 | /* |
548 | * Return an indication of where the new directory |
549 | * entry should be put. If we didn't find a slot, |
550 | * then set results->ulr_count to 0 indicating |
551 | * that the new slot belongs at the end of the |
552 | * directory. If we found a slot, then the new entry |
553 | * can be put in the range from results->ulr_offset to |
554 | * results->ulr_offset + results->ulr_count. |
555 | */ |
556 | if (slotstatus == NONE) { |
557 | results->ulr_offset = roundup(ext2fs_size(dp), dirblksiz); |
558 | results->ulr_count = 0; |
559 | enduseful = results->ulr_offset; |
560 | } else { |
561 | results->ulr_offset = slotoffset; |
562 | results->ulr_count = slotsize; |
563 | if (enduseful < slotoffset + slotsize) |
564 | enduseful = slotoffset + slotsize; |
565 | } |
566 | results->ulr_endoff = roundup(enduseful, dirblksiz); |
567 | #if 0 |
568 | dp->i_flag |= IN_CHANGE | IN_UPDATE; |
569 | #endif |
570 | /* |
571 | * We return with the directory locked, so that |
572 | * the parameters we set up above will still be |
573 | * valid if we actually decide to do a direnter(). |
574 | * We return ni_vp == NULL to indicate that the entry |
575 | * does not currently exist; we leave a pointer to |
576 | * the (locked) directory inode in ndp->ni_dvp. |
577 | * |
578 | * NB - if the directory is unlocked, then this |
579 | * information cannot be used. |
580 | */ |
581 | return EJUSTRETURN; |
582 | } |
583 | /* |
584 | * Insert name into cache (as non-existent) if appropriate. |
585 | */ |
586 | if (nameiop != CREATE) { |
587 | cache_enter(vdp, *vpp, cnp->cn_nameptr, cnp->cn_namelen, |
588 | cnp->cn_flags); |
589 | } |
590 | return ENOENT; |
591 | |
592 | found: |
593 | if (numdirpasses == 2) |
594 | namecache_count_pass2(); |
595 | /* |
596 | * Check that directory length properly reflects presence |
597 | * of this entry. |
598 | */ |
599 | if (results->ulr_offset + EXT2FS_DIRSIZ(ep->e2d_namlen) > ext2fs_size(dp)) { |
600 | ufs_dirbad(dp, results->ulr_offset, "i_size too small" ); |
601 | error = ext2fs_setsize(dp, |
602 | results->ulr_offset + EXT2FS_DIRSIZ(ep->e2d_namlen)); |
603 | if (error) { |
604 | brelse(bp, 0); |
605 | return error; |
606 | } |
607 | dp->i_flag |= IN_CHANGE | IN_UPDATE; |
608 | uvm_vnp_setsize(vdp, ext2fs_size(dp)); |
609 | } |
610 | brelse(bp, 0); |
611 | |
612 | /* |
613 | * Found component in pathname. |
614 | * If the final component of path name, save information |
615 | * in the cache as to where the entry was found. |
616 | */ |
617 | if ((flags & ISLASTCN) && nameiop == LOOKUP) |
618 | results->ulr_diroff = results->ulr_offset &~ (dirblksiz - 1); |
619 | |
620 | /* |
621 | * If deleting, and at end of pathname, return |
622 | * parameters which can be used to remove file. |
623 | * Lock the inode, being careful with ".". |
624 | */ |
625 | if (nameiop == DELETE && (flags & ISLASTCN)) { |
626 | /* |
627 | * Return pointer to current entry in results->ulr_offset, |
628 | * and distance past previous entry (if there |
629 | * is a previous entry in this block) in results->ulr_count. |
630 | * Save directory inode pointer in ndp->ni_dvp for dirremove(). |
631 | */ |
632 | if ((results->ulr_offset & (dirblksiz - 1)) == 0) |
633 | results->ulr_count = 0; |
634 | else |
635 | results->ulr_count = results->ulr_offset - prevoff; |
636 | if (dp->i_number == foundino) { |
637 | vref(vdp); |
638 | tdp = vdp; |
639 | } else { |
640 | error = vcache_get(vdp->v_mount, |
641 | &foundino, sizeof(foundino), &tdp); |
642 | if (error) |
643 | return error; |
644 | } |
645 | /* |
646 | * Write access to directory required to delete files. |
647 | */ |
648 | if ((error = VOP_ACCESS(vdp, VWRITE, cred)) != 0) { |
649 | vrele(tdp); |
650 | return error; |
651 | } |
652 | /* |
653 | * If directory is "sticky", then user must own |
654 | * the directory, or the file in it, else she |
655 | * may not delete it (unless she's root). This |
656 | * implements append-only directories. |
657 | */ |
658 | if (dp->i_e2fs_mode & ISVTX) { |
659 | error = kauth_authorize_vnode(cred, KAUTH_VNODE_DELETE, |
660 | tdp, vdp, genfs_can_sticky(cred, dp->i_uid, |
661 | VTOI(tdp)->i_uid)); |
662 | if (error) { |
663 | vrele(tdp); |
664 | return EPERM; |
665 | } |
666 | } |
667 | *vpp = tdp; |
668 | return 0; |
669 | } |
670 | |
671 | /* |
672 | * If rewriting (RENAME), return the inode and the |
673 | * information required to rewrite the present directory |
674 | * Must get inode of directory entry to verify it's a |
675 | * regular file, or empty directory. |
676 | */ |
677 | if (nameiop == RENAME && (flags & ISLASTCN)) { |
678 | error = VOP_ACCESS(vdp, VWRITE, cred); |
679 | if (error) |
680 | return error; |
681 | /* |
682 | * Careful about locking second inode. |
683 | * This can only occur if the target is ".". |
684 | */ |
685 | if (dp->i_number == foundino) |
686 | return EISDIR; |
687 | error = vcache_get(vdp->v_mount, |
688 | &foundino, sizeof(foundino), &tdp); |
689 | if (error) |
690 | return error; |
691 | *vpp = tdp; |
692 | return 0; |
693 | } |
694 | |
695 | if (dp->i_number == foundino) { |
696 | vref(vdp); /* we want ourself, ie "." */ |
697 | *vpp = vdp; |
698 | } else { |
699 | error = vcache_get(vdp->v_mount, |
700 | &foundino, sizeof(foundino), &tdp); |
701 | if (error) |
702 | return error; |
703 | *vpp = tdp; |
704 | } |
705 | |
706 | /* |
707 | * Insert name into cache if appropriate. |
708 | */ |
709 | cache_enter(vdp, *vpp, cnp->cn_nameptr, cnp->cn_namelen, cnp->cn_flags); |
710 | return 0; |
711 | } |
712 | static void |
713 | ext2fs_accumulatespace (struct ext2fs_searchslot *ssp, struct ext2fs_direct *ep, |
714 | doff_t *offp) |
715 | { |
716 | int size = ep->e2d_reclen; |
717 | |
718 | if (ep->e2d_ino != 0) |
719 | size -= EXT2_DIR_REC_LEN(ep->e2d_namlen); |
720 | |
721 | if (size <= 0) |
722 | return; |
723 | |
724 | if (size >= ssp->slotneeded) { |
725 | ssp->slotstatus = FOUND; |
726 | ssp->slotoffset = *offp; |
727 | ssp->slotsize = ep->e2d_reclen; |
728 | return; |
729 | } |
730 | |
731 | if (ssp->slotstatus != NONE) |
732 | return; |
733 | |
734 | ssp->slotfreespace += size; |
735 | if (ssp->slotoffset == -1) |
736 | ssp->slotoffset = *offp; |
737 | |
738 | if (ssp->slotfreespace >= ssp->slotneeded) { |
739 | ssp->slotstatus = COMPACT; |
740 | ssp->slotsize = *offp + ep->e2d_reclen - ssp->slotoffset; |
741 | } |
742 | } |
743 | |
744 | int |
745 | ext2fs_search_dirblock(struct inode *ip, void *data, int *foundp, |
746 | const char *name, int namelen, int *entryoffsetinblockp, |
747 | doff_t *offp, doff_t *prevoffp, doff_t *endusefulp, |
748 | struct ext2fs_searchslot *ssp) |
749 | { |
750 | struct vnode *vdp = ITOV(ip); |
751 | struct ext2fs_direct *ep, *top; |
752 | uint32_t bsize = ip->i_e2fs->e2fs_bsize; |
753 | int offset = *entryoffsetinblockp; |
754 | int namlen; |
755 | |
756 | ep = (void *)((char *)data + offset); |
757 | top = (void *)((char *)data + bsize - EXT2_DIR_REC_LEN(0)); |
758 | |
759 | while (ep < top) { |
760 | /* |
761 | * Full validation checks are slow, so we only check |
762 | * enough to insure forward progress through the |
763 | * directory. Complete checks can be run by setting |
764 | * "vfs.e2fs.dirchk" to be true. |
765 | */ |
766 | if (ep->e2d_reclen == 0 || |
767 | (dirchk && ext2fs_dirbadentry(vdp, ep, offset))) { |
768 | int i; |
769 | ufs_dirbad(ip, *offp, "mangled entry" ); |
770 | i = bsize - (offset & (bsize - 1)); |
771 | *offp += i; |
772 | offset += i; |
773 | continue; |
774 | } |
775 | |
776 | /* |
777 | * If an appropriate sized slot has not yet been found, |
778 | * check to see if one is available. Also accumulate space |
779 | * in the current block so that we can determine if |
780 | * compaction is viable. |
781 | */ |
782 | if (ssp->slotstatus != FOUND) |
783 | ext2fs_accumulatespace(ssp, ep, offp); |
784 | |
785 | /* |
786 | * Check for a name match. |
787 | */ |
788 | if (ep->e2d_ino) { |
789 | namlen = ep->e2d_namlen; |
790 | if (namlen == namelen && |
791 | !memcmp(name, ep->e2d_name, (unsigned)namlen)) { |
792 | /* |
793 | * Save directory entry's inode number and |
794 | * reclen in ndp->ni_ufs area, and release |
795 | * directory buffer. |
796 | */ |
797 | *foundp = 1; |
798 | return 0; |
799 | } |
800 | } |
801 | *prevoffp = *offp; |
802 | *offp += ep->e2d_reclen; |
803 | offset += ep->e2d_reclen; |
804 | *entryoffsetinblockp = offset; |
805 | if (ep->e2d_ino) |
806 | *endusefulp = *offp; |
807 | /* |
808 | * Get pointer to the next entry. |
809 | */ |
810 | ep = (void *)((char *)data + offset); |
811 | } |
812 | |
813 | return 0; |
814 | } |
815 | |
816 | /* |
817 | * Do consistency checking on a directory entry: |
818 | * record length must be multiple of 4 |
819 | * entry must fit in rest of its dirblksize block |
820 | * record must be large enough to contain entry |
821 | * name is not longer than EXT2FS_MAXNAMLEN |
822 | * name must be as long as advertised, and null terminated |
823 | */ |
824 | /* |
825 | * changed so that it confirms to ext2fs_check_dir_entry |
826 | */ |
827 | static int |
828 | ext2fs_dirbadentry(struct vnode *dp, struct ext2fs_direct *de, |
829 | int entryoffsetinblock) |
830 | { |
831 | struct ufsmount *ump = VFSTOUFS(dp->v_mount); |
832 | int dirblksiz = ump->um_dirblksiz; |
833 | |
834 | const char *error_msg = NULL; |
835 | int reclen = fs2h16(de->e2d_reclen); |
836 | int namlen = de->e2d_namlen; |
837 | |
838 | if (reclen < EXT2FS_DIRSIZ(1)) /* e2d_namlen = 1 */ |
839 | error_msg = "rec_len is smaller than minimal" ; |
840 | else if (reclen % 4 != 0) |
841 | error_msg = "rec_len % 4 != 0" ; |
842 | else if (namlen > EXT2FS_MAXNAMLEN) |
843 | error_msg = "namlen > EXT2FS_MAXNAMLEN" ; |
844 | else if (reclen < EXT2FS_DIRSIZ(namlen)) |
845 | error_msg = "reclen is too small for name_len" ; |
846 | else if (entryoffsetinblock + reclen > dirblksiz) |
847 | error_msg = "directory entry across blocks" ; |
848 | else if (fs2h32(de->e2d_ino) > |
849 | VTOI(dp)->i_e2fs->e2fs.e2fs_icount) |
850 | error_msg = "inode out of bounds" ; |
851 | |
852 | if (error_msg != NULL) { |
853 | printf( "bad directory entry: %s\n" |
854 | "offset=%d, inode=%lu, rec_len=%d, name_len=%d \n" , |
855 | error_msg, entryoffsetinblock, |
856 | (unsigned long) fs2h32(de->e2d_ino), |
857 | reclen, namlen); |
858 | panic("ext2fs_dirbadentry" ); |
859 | } |
860 | return error_msg == NULL ? 0 : 1; |
861 | } |
862 | |
863 | /* |
864 | * Write a directory entry after a call to namei, using the parameters |
865 | * that it left in nameidata. The argument ip is the inode which the new |
866 | * directory entry will refer to. Dvp is a pointer to the directory to |
867 | * be written, which was left locked by namei. Remaining parameters |
868 | * (ulr_offset, ulr_count) indicate how the space for the new |
869 | * entry is to be obtained. |
870 | */ |
871 | int |
872 | ext2fs_direnter(struct inode *ip, struct vnode *dvp, |
873 | const struct ufs_lookup_results *ulr, struct componentname *cnp) |
874 | { |
875 | struct inode *dp; |
876 | struct ext2fs_direct newdir; |
877 | struct iovec aiov; |
878 | struct uio auio; |
879 | int error; |
880 | struct ufsmount *ump = VFSTOUFS(dvp->v_mount); |
881 | int dirblksiz = ump->um_dirblksiz; |
882 | size_t newentrysize; |
883 | |
884 | dp = VTOI(dvp); |
885 | |
886 | newdir.e2d_ino = h2fs32(ip->i_number); |
887 | newdir.e2d_namlen = cnp->cn_namelen; |
888 | if (EXT2F_HAS_INCOMPAT_FEATURE(ip->i_e2fs, EXT2F_INCOMPAT_FTYPE)) { |
889 | newdir.e2d_type = inot2ext2dt(IFTODT(ip->i_e2fs_mode)); |
890 | } else { |
891 | newdir.e2d_type = 0; |
892 | } |
893 | memcpy(newdir.e2d_name, cnp->cn_nameptr, (unsigned)cnp->cn_namelen + 1); |
894 | newentrysize = EXT2FS_DIRSIZ(cnp->cn_namelen); |
895 | |
896 | if (ext2fs_htree_has_idx(dp)) { |
897 | error = ext2fs_htree_add_entry(dvp, &newdir, cnp, newentrysize); |
898 | if (error) { |
899 | dp->i_e2fs_flags &= ~EXT2_INDEX; |
900 | dp->i_flag |= IN_CHANGE | IN_UPDATE; |
901 | } |
902 | return error; |
903 | } |
904 | |
905 | /* |
906 | * TODO check if Htree index is not created for the directory then |
907 | * create one if directory entries get overflew the first dir-block |
908 | */ |
909 | if (ulr->ulr_count == 0) { |
910 | /* |
911 | * If ulr_count is 0, then namei could find no |
912 | * space in the directory. Here, ulr_offset will |
913 | * be on a directory block boundary and we will write the |
914 | * new entry into a fresh block. |
915 | */ |
916 | if (ulr->ulr_offset & (dirblksiz - 1)) |
917 | panic("ext2fs_direnter: newblk" ); |
918 | auio.uio_offset = ulr->ulr_offset; |
919 | newdir.e2d_reclen = h2fs16(dirblksiz); |
920 | auio.uio_resid = newentrysize; |
921 | aiov.iov_len = newentrysize; |
922 | aiov.iov_base = (void *)&newdir; |
923 | auio.uio_iov = &aiov; |
924 | auio.uio_iovcnt = 1; |
925 | auio.uio_rw = UIO_WRITE; |
926 | UIO_SETUP_SYSSPACE(&auio); |
927 | error = ext2fs_bufwr(dvp, &auio, IO_SYNC, cnp->cn_cred); |
928 | if (dirblksiz > dvp->v_mount->mnt_stat.f_bsize) |
929 | /* XXX should grow with balloc() */ |
930 | panic("ext2fs_direnter: frag size" ); |
931 | else if (!error) { |
932 | error = ext2fs_setsize(dp, |
933 | roundup(ext2fs_size(dp), dirblksiz)); |
934 | if (error) |
935 | return error; |
936 | dp->i_flag |= IN_CHANGE; |
937 | uvm_vnp_setsize(dvp, ext2fs_size(dp)); |
938 | } |
939 | return error; |
940 | } |
941 | |
942 | error = ext2fs_add_entry(dvp, &newdir, ulr, newentrysize); |
943 | |
944 | if (!error && ulr->ulr_endoff && ulr->ulr_endoff < ext2fs_size(dp)) |
945 | error = ext2fs_truncate(dvp, (off_t)ulr->ulr_endoff, IO_SYNC, |
946 | cnp->cn_cred); |
947 | return error; |
948 | } |
949 | |
950 | /* |
951 | * Insert an entry into the directory block. |
952 | * Compact the contents. |
953 | */ |
954 | |
955 | int |
956 | ext2fs_add_entry(struct vnode* dvp, struct ext2fs_direct *entry, |
957 | const struct ufs_lookup_results *ulr, size_t newentrysize) |
958 | { |
959 | struct ext2fs_direct *ep, *nep; |
960 | struct inode *dp; |
961 | struct buf *bp; |
962 | u_int dsize; |
963 | int error, loc, spacefree; |
964 | char *dirbuf; |
965 | |
966 | dp = VTOI(dvp); |
967 | |
968 | /* |
969 | * If ulr_count is non-zero, then namei found space |
970 | * for the new entry in the range ulr_offset to |
971 | * ulr_offset + ulr_count in the directory. |
972 | * To use this space, we may have to compact the entries located |
973 | * there, by copying them together towards the beginning of the |
974 | * block, leaving the free space in one usable chunk at the end. |
975 | */ |
976 | |
977 | /* |
978 | * Get the block containing the space for the new directory entry. |
979 | */ |
980 | if ((error = ext2fs_blkatoff(dvp, (off_t)ulr->ulr_offset, &dirbuf, &bp)) != 0) |
981 | return error; |
982 | /* |
983 | * Find space for the new entry. In the simple case, the entry at |
984 | * offset base will have the space. If it does not, then namei |
985 | * arranged that compacting the region ulr_offset to |
986 | * ulr_offset + ulr_count would yield the |
987 | * space. |
988 | */ |
989 | ep = (struct ext2fs_direct *)dirbuf; |
990 | dsize = EXT2FS_DIRSIZ(ep->e2d_namlen); |
991 | spacefree = fs2h16(ep->e2d_reclen) - dsize; |
992 | for (loc = fs2h16(ep->e2d_reclen); loc < ulr->ulr_count;) { |
993 | nep = (struct ext2fs_direct *)(dirbuf + loc); |
994 | if (ep->e2d_ino) { |
995 | /* trim the existing slot */ |
996 | ep->e2d_reclen = h2fs16(dsize); |
997 | ep = (struct ext2fs_direct *)((char *)ep + dsize); |
998 | } else { |
999 | /* overwrite; nothing there; header is ours */ |
1000 | spacefree += dsize; |
1001 | } |
1002 | dsize = EXT2FS_DIRSIZ(nep->e2d_namlen); |
1003 | spacefree += fs2h16(nep->e2d_reclen) - dsize; |
1004 | loc += fs2h16(nep->e2d_reclen); |
1005 | memcpy((void *)ep, (void *)nep, dsize); |
1006 | } |
1007 | /* |
1008 | * Update the pointer fields in the previous entry (if any), |
1009 | * copy in the new entry, and write out the block. |
1010 | */ |
1011 | if (ep->e2d_ino == 0) { |
1012 | #ifdef DIAGNOSTIC |
1013 | if (spacefree + dsize < newentrysize) |
1014 | panic("ext2fs_direnter: compact1" ); |
1015 | #endif |
1016 | entry->e2d_reclen = h2fs16(spacefree + dsize); |
1017 | } else { |
1018 | #ifdef DIAGNOSTIC |
1019 | if (spacefree < newentrysize) { |
1020 | printf("ext2fs_direnter: compact2 %u %u" , |
1021 | (u_int)spacefree, (u_int)newentrysize); |
1022 | panic("ext2fs_direnter: compact2" ); |
1023 | } |
1024 | #endif |
1025 | entry->e2d_reclen = h2fs16(spacefree); |
1026 | ep->e2d_reclen = h2fs16(dsize); |
1027 | ep = (struct ext2fs_direct *)((char *)ep + dsize); |
1028 | } |
1029 | memcpy(ep, entry, (u_int)newentrysize); |
1030 | error = VOP_BWRITE(bp->b_vp, bp); |
1031 | dp->i_flag |= IN_CHANGE | IN_UPDATE; |
1032 | return error; |
1033 | } |
1034 | |
1035 | /* |
1036 | * Remove a directory entry after a call to namei, using |
1037 | * the auxiliary results it provided. The entry |
1038 | * ulr_offset contains the offset into the directory of the |
1039 | * entry to be eliminated. The ulr_count field contains the |
1040 | * size of the previous record in the directory. If this |
1041 | * is 0, the first entry is being deleted, so we need only |
1042 | * zero the inode number to mark the entry as free. If the |
1043 | * entry is not the first in the directory, we must reclaim |
1044 | * the space of the now empty record by adding the record size |
1045 | * to the size of the previous entry. |
1046 | */ |
1047 | int |
1048 | ext2fs_dirremove(struct vnode *dvp, const struct ufs_lookup_results *ulr, |
1049 | struct componentname *cnp) |
1050 | { |
1051 | struct inode *dp; |
1052 | struct ext2fs_direct *ep; |
1053 | struct buf *bp; |
1054 | int error; |
1055 | |
1056 | dp = VTOI(dvp); |
1057 | |
1058 | if (ulr->ulr_count == 0) { |
1059 | /* |
1060 | * First entry in block: set d_ino to zero. |
1061 | */ |
1062 | error = ext2fs_blkatoff(dvp, (off_t)ulr->ulr_offset, |
1063 | (void *)&ep, &bp); |
1064 | if (error != 0) |
1065 | return error; |
1066 | ep->e2d_ino = 0; |
1067 | error = VOP_BWRITE(bp->b_vp, bp); |
1068 | dp->i_flag |= IN_CHANGE | IN_UPDATE; |
1069 | return error; |
1070 | } |
1071 | /* |
1072 | * Collapse new free space into previous entry. |
1073 | */ |
1074 | error = ext2fs_blkatoff(dvp, (off_t)(ulr->ulr_offset - ulr->ulr_count), |
1075 | (void *)&ep, &bp); |
1076 | if (error != 0) |
1077 | return error; |
1078 | ep->e2d_reclen = h2fs16(fs2h16(ep->e2d_reclen) + ulr->ulr_reclen); |
1079 | error = VOP_BWRITE(bp->b_vp, bp); |
1080 | dp->i_flag |= IN_CHANGE | IN_UPDATE; |
1081 | return error; |
1082 | } |
1083 | |
1084 | /* |
1085 | * Rewrite an existing directory entry to point at the inode |
1086 | * supplied. The parameters describing the directory entry are |
1087 | * set up by a call to namei. |
1088 | */ |
1089 | int |
1090 | ext2fs_dirrewrite(struct inode *dp, const struct ufs_lookup_results *ulr, |
1091 | struct inode *ip, struct componentname *cnp) |
1092 | { |
1093 | struct buf *bp; |
1094 | struct ext2fs_direct *ep; |
1095 | struct vnode *vdp = ITOV(dp); |
1096 | int error; |
1097 | |
1098 | error = ext2fs_blkatoff(vdp, (off_t)ulr->ulr_offset, (void *)&ep, &bp); |
1099 | if (error != 0) |
1100 | return error; |
1101 | ep->e2d_ino = h2fs32(ip->i_number); |
1102 | if (EXT2F_HAS_INCOMPAT_FEATURE(dp->i_e2fs, EXT2F_INCOMPAT_FTYPE)) { |
1103 | ep->e2d_type = inot2ext2dt(IFTODT(ip->i_e2fs_mode)); |
1104 | } else { |
1105 | ep->e2d_type = 0; |
1106 | } |
1107 | error = VOP_BWRITE(bp->b_vp, bp); |
1108 | dp->i_flag |= IN_CHANGE | IN_UPDATE; |
1109 | return error; |
1110 | } |
1111 | |
1112 | /* |
1113 | * Check if a directory is empty or not. |
1114 | * Inode supplied must be locked. |
1115 | * |
1116 | * Using a struct dirtemplate here is not precisely |
1117 | * what we want, but better than using a struct ext2fs_direct. |
1118 | * |
1119 | * NB: does not handle corrupted directories. |
1120 | */ |
1121 | int |
1122 | ext2fs_dirempty(struct inode *ip, ino_t parentino, kauth_cred_t cred) |
1123 | { |
1124 | off_t off; |
1125 | struct ext2fs_dirtemplate dbuf; |
1126 | struct ext2fs_direct *dp = (struct ext2fs_direct *)&dbuf; |
1127 | int error, namlen; |
1128 | size_t count; |
1129 | |
1130 | #define MINDIRSIZ (sizeof (struct ext2fs_dirtemplate) / 2) |
1131 | |
1132 | for (off = 0; off < ext2fs_size(ip); off += fs2h16(dp->e2d_reclen)) { |
1133 | error = ufs_bufio(UIO_READ, ITOV(ip), (void *)dp, MINDIRSIZ, |
1134 | off, IO_NODELOCKED, cred, &count, NULL); |
1135 | /* |
1136 | * Since we read MINDIRSIZ, residual must |
1137 | * be 0 unless we're at end of file. |
1138 | */ |
1139 | if (error || count != 0) |
1140 | return 0; |
1141 | /* avoid infinite loops */ |
1142 | if (dp->e2d_reclen == 0) |
1143 | return 0; |
1144 | /* skip empty entries */ |
1145 | if (dp->e2d_ino == 0) |
1146 | continue; |
1147 | /* accept only "." and ".." */ |
1148 | namlen = dp->e2d_namlen; |
1149 | if (namlen > 2) |
1150 | return 0; |
1151 | if (dp->e2d_name[0] != '.') |
1152 | return 0; |
1153 | /* |
1154 | * At this point namlen must be 1 or 2. |
1155 | * 1 implies ".", 2 implies ".." if second |
1156 | * char is also "." |
1157 | */ |
1158 | if (namlen == 1) |
1159 | continue; |
1160 | if (dp->e2d_name[1] == '.' && fs2h32(dp->e2d_ino) == parentino) |
1161 | continue; |
1162 | return 0; |
1163 | } |
1164 | return 1; |
1165 | } |
1166 | |