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
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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>
54 * Convert a component of a pathname into a pointer to a locked inode.
55 * This is a very central and rather complicated routine.
56 * If the filesystem is not maintained in a strict tree hierarchy,
57 * this can result in a deadlock situation (see comments in code below).
59 * The flag argument is LOOKUP, CREATE, RENAME, or DELETE depending on
60 * whether the name is to be looked up, created, renamed, or deleted.
61 * When CREATE, RENAME, or DELETE is specified, information usable in
62 * creating, renaming, or deleting a directory entry may be calculated.
63 * If flag has LOCKPARENT or'ed into it and the target of the pathname
64 * exists, lookup returns both the target and its parent directory locked.
65 * When creating or renaming and LOCKPARENT is specified, the target may
66 * not be ".". When deleting and LOCKPARENT is specified, the target may
67 * be "."., but the caller must check to ensure it does an vrele and iput
68 * instead of two iputs.
70 * Overall outline of ufs_lookup:
72 * search for name in directory, to found or notfound
74 * if creating, return locked directory, leaving info on available slots
77 * if at end of path and deleting, return information to allow delete
78 * if at end of path and rewriting (RENAME and LOCKPARENT), lock target
79 * inode and return info to allow rewrite
80 * if not at end, add name to cache; if at end and neither creating
81 * nor deleting, add name to cache
83 * NOTE: (LOOKUP | LOCKPARENT) currently returns the parent inode unlocked.
87 struct vop_cachedlookup_args /* {
90 struct componentname *a_cnp;
93 struct vnode *vdp; /* vnode for directory being searched */
94 struct iso_node *dp; /* inode for directory being searched */
95 struct iso_mnt *imp; /* filesystem that directory is in */
96 struct buf *bp; /* a buffer of directory entries */
97 struct iso_directory_record *ep = 0;/* the current directory entry */
98 int entryoffsetinblock; /* offset of ep in bp's buffer */
99 int saveoffset = 0; /* offset of last directory entry in dir */
100 int numdirpasses; /* strategy for directory search */
101 doff_t endsearch; /* offset to end directory search */
102 struct vnode *pdp; /* saved dp during symlink work */
103 struct vnode *tdp; /* returned by cd9660_vget_internal */
104 u_long bmask; /* block offset mask */
106 ino_t ino = 0, saved_ino;
110 char altname[NAME_MAX];
114 struct vnode **vpp = ap->a_vpp;
115 struct componentname *cnp = ap->a_cnp;
116 int flags = cnp->cn_flags;
117 int nameiop = cnp->cn_nameiop;
126 * We now have a segment name to search for, and a directory to search.
129 len = cnp->cn_namelen;
130 name = cnp->cn_nameptr;
132 * A leading `=' means, we are looking for an associated file
134 if ((assoc = (imp->iso_ftype != ISO_FTYPE_RRIP && *name == ASSOCCHAR)))
141 * If there is cached information on a previous search of
142 * this directory, pick up where we last left off.
143 * We cache only lookups as these are the most common
144 * and have the greatest payoff. Caching CREATE has little
145 * benefit as it usually must search the entire directory
146 * to determine that the entry does not exist. Caching the
147 * location of the last DELETE or RENAME has not reduced
148 * profiling time and hence has been removed in the interest
151 bmask = imp->im_bmask;
152 if (nameiop != LOOKUP || dp->i_diroff == 0 ||
153 dp->i_diroff > dp->i_size) {
154 entryoffsetinblock = 0;
158 dp->i_offset = dp->i_diroff;
159 if ((entryoffsetinblock = dp->i_offset & bmask) &&
160 (error = cd9660_blkatoff(vdp, (off_t)dp->i_offset, NULL, &bp)))
163 nchstats.ncs_2passes++;
165 endsearch = dp->i_size;
168 while (dp->i_offset < endsearch) {
170 * If offset is on a block boundary,
171 * read the next directory block.
172 * Release previous if it exists.
174 if ((dp->i_offset & bmask) == 0) {
178 cd9660_blkatoff(vdp, (off_t)dp->i_offset, NULL, &bp)) != 0)
180 entryoffsetinblock = 0;
183 * Get pointer to next entry.
185 ep = (struct iso_directory_record *)
186 ((char *)bp->b_data + entryoffsetinblock);
188 reclen = isonum_711(ep->length);
190 /* skip to next block, if any */
192 (dp->i_offset & ~bmask) + imp->logical_block_size;
196 if (reclen < ISO_DIRECTORY_RECORD_SIZE)
197 /* illegal entry, stop */
200 if (entryoffsetinblock + reclen > imp->logical_block_size)
201 /* entries are not allowed to cross boundaries */
204 namelen = isonum_711(ep->name_len);
205 isoflags = isonum_711(imp->iso_ftype == ISO_FTYPE_HIGH_SIERRA?
206 &ep->date[6]: ep->flags);
208 if (reclen < ISO_DIRECTORY_RECORD_SIZE + namelen)
209 /* illegal entry, stop */
213 * Check for a name match.
215 switch (imp->iso_ftype) {
217 if (!(isoflags & 4) == !assoc) {
220 || (flags & ISDOTDOT)) {
222 && ep->name[0] == ((flags & ISDOTDOT) ? 1 : 0)) {
224 * Save directory entry's inode number and
225 * release directory buffer.
227 dp->i_ino = isodirino(ep, imp);
233 } else if (!(res = isofncmp(name, len,
240 ino = isodirino(ep, imp);
242 ino = dbtob(bp->b_blkno)
243 + entryoffsetinblock;
244 saveoffset = dp->i_offset;
247 #ifdef NOSORTBUG /* On some CDs directory entries are not sorted correctly */
250 else if (res > 0 && numdirpasses == 2)
256 if (isonum_711(ep->flags)&2)
257 ino = isodirino(ep, imp);
259 ino = dbtob(bp->b_blkno) + entryoffsetinblock;
261 cd9660_rrip_getname(ep,altname,&namelen,&dp->i_ino,imp);
262 if (namelen == cnp->cn_namelen
263 && !bcmp(name,altname,namelen))
268 dp->i_offset += reclen;
269 entryoffsetinblock += reclen;
274 if (saveoffset != dp->i_offset) {
275 if (lblkno(imp, dp->i_offset) !=
276 lblkno(imp, saveoffset)) {
279 if ((error = cd9660_blkatoff(vdp,
280 (off_t)saveoffset, NULL, &bp)) != 0)
283 entryoffsetinblock = saveoffset & bmask;
284 ep = (struct iso_directory_record *)
285 ((char *)bp->b_data + entryoffsetinblock);
286 dp->i_offset = saveoffset;
292 * If we started in the middle of the directory and failed
293 * to find our target, we must check the beginning as well.
295 if (numdirpasses == 2) {
298 endsearch = dp->i_diroff;
305 * Insert name into cache (as non-existent) if appropriate.
307 if (cnp->cn_flags & MAKEENTRY)
308 cache_enter(vdp, *vpp, cnp);
309 if (nameiop == CREATE || nameiop == RENAME)
314 if (numdirpasses == 2)
315 nchstats.ncs_pass2++;
318 * Found component in pathname.
319 * If the final component of path name, save information
320 * in the cache as to where the entry was found.
322 if ((flags & ISLASTCN) && nameiop == LOOKUP)
323 dp->i_diroff = dp->i_offset;
326 * Step through the translation in the name. We do not `iput' the
327 * directory because we may need it again if a symbolic link
328 * is relative to the current directory. Instead we save it
329 * unlocked as "pdp". We must get the target inode before unlocking
330 * the directory to insure that the inode will not be removed
331 * before we get it. We prevent deadlock by always fetching
332 * inodes from the root, moving down the directory tree. Thus
333 * when following backward pointers ".." we must unlock the
334 * parent directory before getting the requested directory.
335 * There is a potential race condition here if both the current
336 * and parent directories are removed before the `iget' for the
337 * inode associated with ".." returns. We hope that this occurs
338 * infrequently since we cannot avoid this race condition without
339 * implementing a sophisticated deadlock detection algorithm.
340 * Note also that this simple deadlock detection scheme will not
341 * work if the filesystem has any hard links other than ".."
342 * that point backwards in the directory structure.
346 * If ino is different from dp->i_ino,
347 * it's a relocated directory.
349 if (flags & ISDOTDOT) {
350 saved_ino = dp->i_ino;
351 VOP_UNLOCK(pdp, 0); /* race to get the inode */
352 error = cd9660_vget_internal(vdp->v_mount, saved_ino,
354 saved_ino != ino, ep);
356 vn_lock(pdp, LK_EXCLUSIVE | LK_RETRY);
360 } else if (dp->i_number == dp->i_ino) {
362 VREF(vdp); /* we want ourself, ie "." */
365 error = cd9660_vget_internal(vdp->v_mount, dp->i_ino,
367 dp->i_ino != ino, ep);
375 * Insert name into cache if appropriate.
377 if (cnp->cn_flags & MAKEENTRY)
378 cache_enter(vdp, *vpp, cnp);
383 * Return buffer with the contents of block "offset" from the beginning of
384 * directory "ip". If "res" is non-zero, fill it in with a pointer to the
385 * remaining space in the directory.
388 cd9660_blkatoff(vp, offset, res, bpp)
398 int bsize, bshift, error;
402 lbn = lblkno(imp, offset);
403 bsize = blksize(imp, ip, lbn);
404 bshift = imp->im_bshift;
406 if ((error = bread(vp, lbn, bsize, NOCRED, &bp)) != 0) {
413 * We must BMAP the buffer because the directory code may use b_blkno
414 * to calculate the inode for certain types of directory entries.
415 * We could get away with not doing it before we VMIO-backed the
416 * directories because the buffers would get freed atomically with
417 * the invalidation of their data. But with VMIO-backed buffers
418 * the buffers may be freed and then later reconstituted - and the
419 * reconstituted buffer will have no knowledge of b_blkno.
421 if (bp->b_blkno == bp->b_lblkno) {
422 bp->b_blkno = (ip->iso_start + bp->b_lblkno) << (bshift - DEV_BSHIFT);
426 *res = (char *)bp->b_data + blkoff(imp, offset);