2 * Copyright (c) 1989, 1993, 1994
3 * The Regents of the University of California. All rights reserved.
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).
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
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.
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
34 * from: @(#)ufs_lookup.c 7.33 (Berkeley) 5/19/91
35 * @(#)cd9660_lookup.c 8.2 (Berkeley) 1/23/94
38 #include <sys/cdefs.h>
39 __FBSDID("$FreeBSD$");
41 #include <sys/param.h>
42 #include <sys/systm.h>
43 #include <sys/namei.h>
46 #include <sys/vnode.h>
47 #include <sys/mount.h>
49 #include <fs/cd9660/iso.h>
50 #include <fs/cd9660/cd9660_node.h>
51 #include <fs/cd9660/iso_rrip.h>
53 struct cd9660_ino_alloc_arg {
56 struct iso_directory_record *ep;
60 cd9660_ino_alloc(struct mount *mp, void *arg, int lkflags,
63 struct cd9660_ino_alloc_arg *dd_arg;
66 return (cd9660_vget_internal(mp, dd_arg->i_ino, lkflags, vpp,
67 dd_arg->i_ino != dd_arg->ino, dd_arg->ep));
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).
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.
87 * Overall outline of ufs_lookup:
89 * search for name in directory, to found or notfound
91 * if creating, return locked directory, leaving info on available slots
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
100 * NOTE: (LOOKUP | LOCKPARENT) currently returns the parent inode unlocked.
104 struct vop_cachedlookup_args /* {
106 struct vnode **a_vpp;
107 struct componentname *a_cnp;
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 */
131 char altname[NAME_MAX];
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;
148 * We now have a segment name to search for, and a directory to search.
151 i_diroff = dp->i_diroff;
152 len = cnp->cn_namelen;
153 name = cnp->cn_nameptr;
156 * A leading `=' means, we are looking for an associated file
158 if ((assoc = (imp->iso_ftype != ISO_FTYPE_RRIP && *name == ASSOCCHAR)))
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
175 bmask = imp->im_bmask;
176 if (nameiop != LOOKUP || i_diroff == 0 || i_diroff > dp->i_size) {
177 entryoffsetinblock = 0;
182 if ((entryoffsetinblock = i_offset & bmask) &&
183 (error = cd9660_blkatoff(vdp, (off_t)i_offset, NULL, &bp)))
186 nchstats.ncs_2passes++;
188 endsearch = dp->i_size;
191 while (i_offset < endsearch) {
193 * If offset is on a block boundary,
194 * read the next directory block.
195 * Release previous if it exists.
197 if ((i_offset & bmask) == 0) {
201 cd9660_blkatoff(vdp, (off_t)i_offset, NULL, &bp)) != 0)
203 entryoffsetinblock = 0;
206 * Get pointer to next entry.
208 ep = (struct iso_directory_record *)
209 ((char *)bp->b_data + entryoffsetinblock);
211 reclen = isonum_711(ep->length);
213 /* skip to next block, if any */
215 (i_offset & ~bmask) + imp->logical_block_size;
219 if (reclen < ISO_DIRECTORY_RECORD_SIZE)
220 /* illegal entry, stop */
223 if (entryoffsetinblock + reclen > imp->logical_block_size)
224 /* entries are not allowed to cross boundaries */
227 namelen = isonum_711(ep->name_len);
228 isoflags = isonum_711(imp->iso_ftype == ISO_FTYPE_HIGH_SIERRA?
229 &ep->date[6]: ep->flags);
231 if (reclen < ISO_DIRECTORY_RECORD_SIZE + namelen)
232 /* illegal entry, stop */
236 * Check for a name match.
238 switch (imp->iso_ftype) {
240 if (!(isoflags & 4) == !assoc) {
243 || (flags & ISDOTDOT)) {
245 && ep->name[0] == ((flags & ISDOTDOT) ? 1 : 0)) {
247 * Save directory entry's inode number and
248 * release directory buffer.
250 i_ino = isodirino(ep, imp);
256 } else if (!(res = isofncmp(name, len,
263 ino = isodirino(ep, imp);
265 ino = dbtob(bp->b_blkno)
266 + entryoffsetinblock;
267 saveoffset = i_offset;
270 #ifdef NOSORTBUG /* On some CDs directory entries are not sorted correctly */
273 else if (res > 0 && numdirpasses == 2)
279 if (isonum_711(ep->flags)&2)
280 ino = isodirino(ep, imp);
282 ino = dbtob(bp->b_blkno) + entryoffsetinblock;
284 cd9660_rrip_getname(ep, altname, &namelen, &i_ino, imp);
285 if (namelen == cnp->cn_namelen
286 && !bcmp(name,altname,namelen))
292 entryoffsetinblock += reclen;
297 if (saveoffset != i_offset) {
298 if (lblkno(imp, i_offset) !=
299 lblkno(imp, saveoffset)) {
302 if ((error = cd9660_blkatoff(vdp,
303 (off_t)saveoffset, NULL, &bp)) != 0)
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;
316 * If we started in the middle of the directory and failed
317 * to find our target, we must check the beginning as well.
319 if (numdirpasses == 2) {
322 endsearch = i_diroff;
329 * Insert name into cache (as non-existent) if appropriate.
331 if (cnp->cn_flags & MAKEENTRY)
332 cache_enter(vdp, *vpp, cnp);
333 if (nameiop == CREATE || nameiop == RENAME)
338 if (numdirpasses == 2)
339 nchstats.ncs_pass2++;
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.
346 if ((flags & ISLASTCN) && nameiop == LOOKUP)
347 dp->i_diroff = i_offset;
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.
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
376 if (dp->i_number != i_ino) {
377 ep2 = malloc(reclen, M_TEMP, M_WAITOK);
378 bcopy(ep, ep2, reclen);
384 * If ino is different from i_ino,
385 * it's a relocated directory.
387 if (flags & ISDOTDOT) {
389 dd_arg.i_ino = i_ino;
391 error = vn_vget_ino_gen(pdp, cd9660_ino_alloc, &dd_arg,
392 cnp->cn_lkflags, &tdp);
397 } else if (dp->i_number == i_ino) {
398 VREF(vdp); /* we want ourself, ie "." */
400 * When we lookup "." we still can be asked to lock it
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);
412 error = cd9660_vget_internal(vdp->v_mount, i_ino,
413 cnp->cn_lkflags, &tdp,
422 * Insert name into cache if appropriate.
424 if (cnp->cn_flags & MAKEENTRY)
425 cache_enter(vdp, *vpp, cnp);
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.
435 cd9660_blkatoff(vp, offset, res, bpp)
445 int bsize, bshift, error;
449 lbn = lblkno(imp, offset);
450 bsize = blksize(imp, ip, lbn);
451 bshift = imp->im_bshift;
453 if ((error = bread(vp, lbn, bsize, NOCRED, &bp)) != 0) {
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.
468 if (bp->b_blkno == bp->b_lblkno) {
469 bp->b_blkno = (ip->iso_start + bp->b_lblkno) << (bshift - DEV_BSHIFT);
473 *res = (char *)bp->b_data + blkoff(imp, offset);