1 /*-
2 * Copyright (c) 1989, 1993, 1994
3 * The Regents of the University of California. All rights reserved.
4 *
5 * This code is derived from software contributed to Berkeley
6 * by Pace Willisson (pace@blitz.com). The Rock Ridge Extension
7 * Support code is derived from software contributed to Berkeley
8 * by Atsushi Murai (amurai@spec.co.jp).
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 4. Neither the name of the University nor the names of its contributors
19 * may be used to endorse or promote products derived from this software
20 * without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 *
34 * from: @(#)ufs_lookup.c 7.33 (Berkeley) 5/19/91
35 * @(#)cd9660_lookup.c 8.2 (Berkeley) 1/23/94
36 */
37
38 #include <sys/cdefs.h>
39 __FBSDID("$FreeBSD$");
40
41 #include <sys/param.h>
42 #include <sys/systm.h>
43 #include <sys/namei.h>
44 #include <sys/bio.h>
45 #include <sys/buf.h>
46 #include <sys/vnode.h>
47 #include <sys/mount.h>
48
49 #include <fs/cd9660/iso.h>
50 #include <fs/cd9660/cd9660_node.h>
51 #include <fs/cd9660/iso_rrip.h>
52
53 struct cd9660_ino_alloc_arg {
54 ino_t ino;
55 ino_t i_ino;
56 struct iso_directory_record *ep;
57 };
58
59 static int
60 cd9660_ino_alloc(struct mount *mp, void *arg, int lkflags,
61 struct vnode **vpp)
62 {
63 struct cd9660_ino_alloc_arg *dd_arg;
64
65 dd_arg = arg;
66 return (cd9660_vget_internal(mp, dd_arg->i_ino, lkflags, vpp,
67 dd_arg->i_ino != dd_arg->ino, dd_arg->ep));
68 }
69
70 /*
71 * Convert a component of a pathname into a pointer to a locked inode.
72 * This is a very central and rather complicated routine.
73 * If the filesystem is not maintained in a strict tree hierarchy,
74 * this can result in a deadlock situation (see comments in code below).
75 *
76 * The flag argument is LOOKUP, CREATE, RENAME, or DELETE depending on
77 * whether the name is to be looked up, created, renamed, or deleted.
78 * When CREATE, RENAME, or DELETE is specified, information usable in
79 * creating, renaming, or deleting a directory entry may be calculated.
80 * If flag has LOCKPARENT or'ed into it and the target of the pathname
81 * exists, lookup returns both the target and its parent directory locked.
82 * When creating or renaming and LOCKPARENT is specified, the target may
83 * not be ".". When deleting and LOCKPARENT is specified, the target may
84 * be "."., but the caller must check to ensure it does an vrele and iput
85 * instead of two iputs.
86 *
87 * Overall outline of ufs_lookup:
88 *
89 * search for name in directory, to found or notfound
90 * notfound:
91 * if creating, return locked directory, leaving info on available slots
92 * else return error
93 * found:
94 * if at end of path and deleting, return information to allow delete
95 * if at end of path and rewriting (RENAME and LOCKPARENT), lock target
96 * inode and return info to allow rewrite
97 * if not at end, add name to cache; if at end and neither creating
98 * nor deleting, add name to cache
99 *
100 * NOTE: (LOOKUP | LOCKPARENT) currently returns the parent inode unlocked.
101 */
102 int
103 cd9660_lookup(ap)
104 struct vop_cachedlookup_args /* {
105 struct vnode *a_dvp;
106 struct vnode **a_vpp;
107 struct componentname *a_cnp;
108 } */ *ap;
109 {
110 struct vnode *vdp; /* vnode for directory being searched */
111 struct iso_node *dp; /* inode for directory being searched */
112 struct iso_mnt *imp; /* filesystem that directory is in */
113 struct buf *bp; /* a buffer of directory entries */
114 struct iso_directory_record *ep;/* the current directory entry */
115 struct iso_directory_record *ep2;/* copy of current directory entry */
116 int entryoffsetinblock; /* offset of ep in bp's buffer */
117 int saveoffset = 0; /* offset of last directory entry in dir */
118 doff_t i_diroff; /* cached i_diroff value. */
119 doff_t i_offset; /* cached i_offset value. */
120 int numdirpasses; /* strategy for directory search */
121 doff_t endsearch; /* offset to end directory search */
122 struct vnode *pdp; /* saved dp during symlink work */
123 struct vnode *tdp; /* returned by cd9660_vget_internal */
124 struct cd9660_ino_alloc_arg dd_arg;
125 u_long bmask; /* block offset mask */
126 int error;
127 ino_t ino, i_ino;
128 int ltype, reclen;
129 u_short namelen;
130 int isoflags;
131 char altname[NAME_MAX];
132 int res;
133 int assoc, len;
134 char *name;
135 struct vnode **vpp = ap->a_vpp;
136 struct componentname *cnp = ap->a_cnp;
137 int flags = cnp->cn_flags;
138 int nameiop = cnp->cn_nameiop;
139
140 ep2 = ep = NULL;
141 bp = NULL;
142 *vpp = NULL;
143 vdp = ap->a_dvp;
144 dp = VTOI(vdp);
145 imp = dp->i_mnt;
146
147 /*
148 * We now have a segment name to search for, and a directory to search.
149 */
150 ino = reclen = 0;
151 i_diroff = dp->i_diroff;
152 len = cnp->cn_namelen;
153 name = cnp->cn_nameptr;
154
155 /*
156 * A leading `=' means, we are looking for an associated file
157 */
158 if ((assoc = (imp->iso_ftype != ISO_FTYPE_RRIP && *name == ASSOCCHAR)))
159 {
160 len--;
161 name++;
162 }
163
164 /*
165 * If there is cached information on a previous search of
166 * this directory, pick up where we last left off.
167 * We cache only lookups as these are the most common
168 * and have the greatest payoff. Caching CREATE has little
169 * benefit as it usually must search the entire directory
170 * to determine that the entry does not exist. Caching the
171 * location of the last DELETE or RENAME has not reduced
172 * profiling time and hence has been removed in the interest
173 * of simplicity.
174 */
175 bmask = imp->im_bmask;
176 if (nameiop != LOOKUP || i_diroff == 0 || i_diroff > dp->i_size) {
177 entryoffsetinblock = 0;
178 i_offset = 0;
179 numdirpasses = 1;
180 } else {
181 i_offset = i_diroff;
182 if ((entryoffsetinblock = i_offset & bmask) &&
183 (error = cd9660_blkatoff(vdp, (off_t)i_offset, NULL, &bp)))
184 return (error);
185 numdirpasses = 2;
186 nchstats.ncs_2passes++;
187 }
188 endsearch = dp->i_size;
189
190 searchloop:
191 while (i_offset < endsearch) {
192 /*
193 * If offset is on a block boundary,
194 * read the next directory block.
195 * Release previous if it exists.
196 */
197 if ((i_offset & bmask) == 0) {
198 if (bp != NULL)
199 brelse(bp);
200 if ((error =
201 cd9660_blkatoff(vdp, (off_t)i_offset, NULL, &bp)) != 0)
202 return (error);
203 entryoffsetinblock = 0;
204 }
205 /*
206 * Get pointer to next entry.
207 */
208 ep = (struct iso_directory_record *)
209 ((char *)bp->b_data + entryoffsetinblock);
210
211 reclen = isonum_711(ep->length);
212 if (reclen == 0) {
213 /* skip to next block, if any */
214 i_offset =
215 (i_offset & ~bmask) + imp->logical_block_size;
216 continue;
217 }
218
219 if (reclen < ISO_DIRECTORY_RECORD_SIZE)
220 /* illegal entry, stop */
221 break;
222
223 if (entryoffsetinblock + reclen > imp->logical_block_size)
224 /* entries are not allowed to cross boundaries */
225 break;
226
227 namelen = isonum_711(ep->name_len);
228 isoflags = isonum_711(imp->iso_ftype == ISO_FTYPE_HIGH_SIERRA?
229 &ep->date[6]: ep->flags);
230
231 if (reclen < ISO_DIRECTORY_RECORD_SIZE + namelen)
232 /* illegal entry, stop */
233 break;
234
235 /*
236 * Check for a name match.
237 */
238 switch (imp->iso_ftype) {
239 default:
240 if (!(isoflags & 4) == !assoc) {
241 if ((len == 1
242 && *name == '.')
243 || (flags & ISDOTDOT)) {
244 if (namelen == 1
245 && ep->name[0] == ((flags & ISDOTDOT) ? 1 : 0)) {
246 /*
247 * Save directory entry's inode number and
248 * release directory buffer.
249 */
250 i_ino = isodirino(ep, imp);
251 goto found;
252 }
253 if (namelen != 1
254 || ep->name[0] != 0)
255 goto notfound;
256 } else if (!(res = isofncmp(name, len,
257 ep->name, namelen,
258 imp->joliet_level,
259 imp->im_flags,
260 imp->im_d2l,
261 imp->im_l2d))) {
262 if (isoflags & 2)
263 ino = isodirino(ep, imp);
264 else
265 ino = dbtob(bp->b_blkno)
266 + entryoffsetinblock;
267 saveoffset = i_offset;
268 } else if (ino)
269 goto foundino;
270 #ifdef NOSORTBUG /* On some CDs directory entries are not sorted correctly */
271 else if (res < 0)
272 goto notfound;
273 else if (res > 0 && numdirpasses == 2)
274 numdirpasses++;
275 #endif
276 }
277 break;
278 case ISO_FTYPE_RRIP:
279 if (isonum_711(ep->flags)&2)
280 ino = isodirino(ep, imp);
281 else
282 ino = dbtob(bp->b_blkno) + entryoffsetinblock;
283 i_ino = ino;
284 cd9660_rrip_getname(ep, altname, &namelen, &i_ino, imp);
285 if (namelen == cnp->cn_namelen
286 && !bcmp(name,altname,namelen))
287 goto found;
288 ino = 0;
289 break;
290 }
291 i_offset += reclen;
292 entryoffsetinblock += reclen;
293 }
294 if (ino) {
295 foundino:
296 i_ino = ino;
297 if (saveoffset != i_offset) {
298 if (lblkno(imp, i_offset) !=
299 lblkno(imp, saveoffset)) {
300 if (bp != NULL)
301 brelse(bp);
302 if ((error = cd9660_blkatoff(vdp,
303 (off_t)saveoffset, NULL, &bp)) != 0)
304 return (error);
305 }
306 entryoffsetinblock = saveoffset & bmask;
307 ep = (struct iso_directory_record *)
308 ((char *)bp->b_data + entryoffsetinblock);
309 reclen = isonum_711(ep->length);
310 i_offset = saveoffset;
311 }
312 goto found;
313 }
314 notfound:
315 /*
316 * If we started in the middle of the directory and failed
317 * to find our target, we must check the beginning as well.
318 */
319 if (numdirpasses == 2) {
320 numdirpasses--;
321 i_offset = 0;
322 endsearch = i_diroff;
323 goto searchloop;
324 }
325 if (bp != NULL)
326 brelse(bp);
327
328 /*
329 * Insert name into cache (as non-existent) if appropriate.
330 */
331 if (cnp->cn_flags & MAKEENTRY)
332 cache_enter(vdp, *vpp, cnp);
333 if (nameiop == CREATE || nameiop == RENAME)
334 return (EROFS);
335 return (ENOENT);
336
337 found:
338 if (numdirpasses == 2)
339 nchstats.ncs_pass2++;
340
341 /*
342 * Found component in pathname.
343 * If the final component of path name, save information
344 * in the cache as to where the entry was found.
345 */
346 if ((flags & ISLASTCN) && nameiop == LOOKUP)
347 dp->i_diroff = i_offset;
348
349 /*
350 * Step through the translation in the name. We do not `vput' the
351 * directory because we may need it again if a symbolic link
352 * is relative to the current directory. Instead we save it
353 * unlocked as "pdp". We must get the target inode before unlocking
354 * the directory to insure that the inode will not be removed
355 * before we get it. We prevent deadlock by always fetching
356 * inodes from the root, moving down the directory tree. Thus
357 * when following backward pointers ".." we must unlock the
358 * parent directory before getting the requested directory.
359 * There is a potential race condition here if both the current
360 * and parent directories are removed before the `vget' for the
361 * inode associated with ".." returns. We hope that this occurs
362 * infrequently since we cannot avoid this race condition without
363 * implementing a sophisticated deadlock detection algorithm.
364 * Note also that this simple deadlock detection scheme will not
365 * work if the filesystem has any hard links other than ".."
366 * that point backwards in the directory structure.
367 */
368 pdp = vdp;
369
370 /*
371 * Make a copy of the directory entry for non "." lookups so
372 * we can drop the buffer before calling vget() to avoid a
373 * lock order reversal between the vnode lock and the buffer
374 * lock.
375 */
376 if (dp->i_number != i_ino) {
377 ep2 = malloc(reclen, M_TEMP, M_WAITOK);
378 bcopy(ep, ep2, reclen);
379 ep = ep2;
380 }
381 brelse(bp);
382
383 /*
384 * If ino is different from i_ino,
385 * it's a relocated directory.
386 */
387 if (flags & ISDOTDOT) {
388 dd_arg.ino = ino;
389 dd_arg.i_ino = i_ino;
390 dd_arg.ep = ep;
391 error = vn_vget_ino_gen(pdp, cd9660_ino_alloc, &dd_arg,
392 cnp->cn_lkflags, &tdp);
393 free(ep2, M_TEMP);
394 if (error != 0)
395 return (error);
396 *vpp = tdp;
397 } else if (dp->i_number == i_ino) {
398 VREF(vdp); /* we want ourself, ie "." */
399 /*
400 * When we lookup "." we still can be asked to lock it
401 * differently.
402 */
403 ltype = cnp->cn_lkflags & LK_TYPE_MASK;
404 if (ltype != VOP_ISLOCKED(vdp)) {
405 if (ltype == LK_EXCLUSIVE)
406 vn_lock(vdp, LK_UPGRADE | LK_RETRY);
407 else /* if (ltype == LK_SHARED) */
408 vn_lock(vdp, LK_DOWNGRADE | LK_RETRY);
409 }
410 *vpp = vdp;
411 } else {
412 error = cd9660_vget_internal(vdp->v_mount, i_ino,
413 cnp->cn_lkflags, &tdp,
414 i_ino != ino, ep);
415 free(ep2, M_TEMP);
416 if (error)
417 return (error);
418 *vpp = tdp;
419 }
420
421 /*
422 * Insert name into cache if appropriate.
423 */
424 if (cnp->cn_flags & MAKEENTRY)
425 cache_enter(vdp, *vpp, cnp);
426 return (0);
427 }
428
429 /*
430 * Return buffer with the contents of block "offset" from the beginning of
431 * directory "ip". If "res" is non-zero, fill it in with a pointer to the
432 * remaining space in the directory.
433 */
434 int
435 cd9660_blkatoff(vp, offset, res, bpp)
436 struct vnode *vp;
437 off_t offset;
438 char **res;
439 struct buf **bpp;
440 {
441 struct iso_node *ip;
442 struct iso_mnt *imp;
443 struct buf *bp;
444 daddr_t lbn;
445 int bsize, bshift, error;
446
447 ip = VTOI(vp);
448 imp = ip->i_mnt;
449 lbn = lblkno(imp, offset);
450 bsize = blksize(imp, ip, lbn);
451 bshift = imp->im_bshift;
452
453 if ((error = bread(vp, lbn, bsize, NOCRED, &bp)) != 0) {
454 brelse(bp);
455 *bpp = NULL;
456 return (error);
457 }
458
459 /*
460 * We must BMAP the buffer because the directory code may use b_blkno
461 * to calculate the inode for certain types of directory entries.
462 * We could get away with not doing it before we VMIO-backed the
463 * directories because the buffers would get freed atomically with
464 * the invalidation of their data. But with VMIO-backed buffers
465 * the buffers may be freed and then later reconstituted - and the
466 * reconstituted buffer will have no knowledge of b_blkno.
467 */
468 if (bp->b_blkno == bp->b_lblkno) {
469 bp->b_blkno = (ip->iso_start + bp->b_lblkno) << (bshift - DEV_BSHIFT);
470 }
471
472 if (res)
473 *res = (char *)bp->b_data + blkoff(imp, offset);
474 *bpp = bp;
475 return (0);
476 }
Cache object: d01a4be23d7c79d2ff052f43d0bc36a6
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