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