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).
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11 * modification, are permitted provided that the following conditions
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14 * notice, this list of conditions and the following disclaimer.
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19 * must display the following acknowledgement:
20 * This product includes software developed by the University of
21 * California, Berkeley and its contributors.
22 * 4. Neither the name of the University nor the names of its contributors
23 * may be used to endorse or promote products derived from this software
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38 * from: @(#)ufs_lookup.c 7.33 (Berkeley) 5/19/91
40 * @(#)cd9660_lookup.c 8.2 (Berkeley) 1/23/94
41 * $FreeBSD: src/sys/isofs/cd9660/cd9660_lookup.c,v 1.23.2.2 2001/11/04 06:19:47 dillon Exp $
42 * $DragonFly: src/sys/vfs/isofs/cd9660/cd9660_lookup.c,v 1.10 2004/04/02 05:46:03 hmp Exp $
45 #include <sys/param.h>
46 #include <sys/systm.h>
48 #include <sys/namei.h>
50 #include <sys/vnode.h>
51 #include <sys/mount.h>
54 #include "cd9660_node.h"
58 * Convert a component of a pathname into a pointer to a locked inode.
59 * This is a very central and rather complicated routine.
60 * If the file system is not maintained in a strict tree hierarchy,
61 * this can result in a deadlock situation (see comments in code below).
63 * The flag argument is LOOKUP, CREATE, RENAME, or DELETE depending on
64 * whether the name is to be looked up, created, renamed, or deleted.
65 * When CREATE, RENAME, or DELETE is specified, information usable in
66 * creating, renaming, or deleting a directory entry may be calculated.
67 * If flag has LOCKPARENT or'ed into it and the target of the pathname
68 * exists, lookup returns both the target and its parent directory locked.
69 * When creating or renaming and LOCKPARENT is specified, the target may
70 * not be ".". When deleting and LOCKPARENT is specified, the target may
71 * be "."., but the caller must check to ensure it does an vrele and iput
72 * instead of two iputs.
74 * Overall outline of ufs_lookup:
76 * search for name in directory, to found or notfound
78 * if creating, return locked directory, leaving info on available slots
81 * if at end of path and deleting, return information to allow delete
82 * if at end of path and rewriting (RENAME and LOCKPARENT), lock target
83 * inode and return info to allow rewrite
84 * if not at end, add name to cache; if at end and neither creating
85 * nor deleting, add name to cache
87 * NOTE: (LOOKUP | LOCKPARENT) currently returns the parent inode unlocked.
91 struct vop_cachedlookup_args /* {
94 struct componentname *a_cnp;
97 struct vnode *vdp; /* vnode for directory being searched */
98 globaldata_t gd = mycpu;
99 struct iso_node *dp; /* inode for directory being searched */
100 struct iso_mnt *imp; /* file system that directory is in */
101 struct buf *bp; /* a buffer of directory entries */
102 struct iso_directory_record *ep = 0;/* the current directory entry */
103 int entryoffsetinblock; /* offset of ep in bp's buffer */
104 int saveoffset = 0; /* offset of last directory entry in dir */
105 int numdirpasses; /* strategy for directory search */
106 doff_t endsearch; /* offset to end directory search */
107 struct vnode *pdp; /* saved dp during symlink work */
108 struct vnode *tdp; /* returned by cd9660_vget_internal */
109 u_long bmask; /* block offset mask */
110 int lockparent; /* 1 => lockparent flag is set */
111 int wantparent; /* 1 => wantparent or lockparent flag */
117 char altname[NAME_MAX];
121 struct vnode **vpp = ap->a_vpp;
122 struct componentname *cnp = ap->a_cnp;
123 int flags = cnp->cn_flags;
124 int nameiop = cnp->cn_nameiop;
125 struct thread *td = cnp->cn_td;
132 lockparent = flags & CNP_LOCKPARENT;
133 wantparent = flags & (CNP_LOCKPARENT | CNP_WANTPARENT);
134 cnp->cn_flags &= ~CNP_PDIRUNLOCK;
137 * We now have a segment name to search for, and a directory to search.
140 len = cnp->cn_namelen;
141 name = cnp->cn_nameptr;
143 * A leading `=' means, we are looking for an associated file
145 if ((assoc = (imp->iso_ftype != ISO_FTYPE_RRIP && *name == ASSOCCHAR)))
152 * If there is cached information on a previous search of
153 * this directory, pick up where we last left off.
154 * We cache only lookups as these are the most common
155 * and have the greatest payoff. Caching CREATE has little
156 * benefit as it usually must search the entire directory
157 * to determine that the entry does not exist. Caching the
158 * location of the last DELETE or RENAME has not reduced
159 * profiling time and hence has been removed in the interest
162 bmask = imp->im_bmask;
163 if (nameiop != NAMEI_LOOKUP || dp->i_diroff == 0 ||
164 dp->i_diroff > dp->i_size) {
165 entryoffsetinblock = 0;
169 dp->i_offset = dp->i_diroff;
170 if ((entryoffsetinblock = dp->i_offset & bmask) &&
171 (error = cd9660_blkatoff(vdp, (off_t)dp->i_offset, NULL, &bp)))
174 gd->gd_nchstats->ncs_2passes++;
176 endsearch = dp->i_size;
179 while (dp->i_offset < endsearch) {
181 * If offset is on a block boundary,
182 * read the next directory block.
183 * Release previous if it exists.
185 if ((dp->i_offset & bmask) == 0) {
189 cd9660_blkatoff(vdp, (off_t)dp->i_offset, NULL, &bp)) != 0)
191 entryoffsetinblock = 0;
194 * Get pointer to next entry.
196 ep = (struct iso_directory_record *)
197 ((char *)bp->b_data + entryoffsetinblock);
199 reclen = isonum_711(ep->length);
201 /* skip to next block, if any */
203 (dp->i_offset & ~bmask) + imp->logical_block_size;
207 if (reclen < ISO_DIRECTORY_RECORD_SIZE)
208 /* illegal entry, stop */
211 if (entryoffsetinblock + reclen > imp->logical_block_size)
212 /* entries are not allowed to cross boundaries */
215 namelen = isonum_711(ep->name_len);
216 isoflags = isonum_711(imp->iso_ftype == ISO_FTYPE_HIGH_SIERRA?
217 &ep->date[6]: ep->flags);
219 if (reclen < ISO_DIRECTORY_RECORD_SIZE + namelen)
220 /* illegal entry, stop */
224 * Check for a name match.
226 switch (imp->iso_ftype) {
228 if (!(isoflags & 4) == !assoc) {
231 || (flags & CNP_ISDOTDOT)) {
233 && ep->name[0] == ((flags & CNP_ISDOTDOT) ? 1 : 0)) {
235 * Save directory entry's inode number and
236 * release directory buffer.
238 dp->i_ino = isodirino(ep, imp);
244 } else if (!(res = isofncmp(name, len, ep->name, namelen, imp->joliet_level))) {
246 ino = isodirino(ep, imp);
248 ino = dbtob(bp->b_blkno)
249 + entryoffsetinblock;
250 saveoffset = dp->i_offset;
253 #ifdef NOSORTBUG /* On some CDs directory entries are not sorted correctly */
256 else if (res > 0 && numdirpasses == 2)
262 if (isonum_711(ep->flags)&2)
263 ino = isodirino(ep, imp);
265 ino = dbtob(bp->b_blkno) + entryoffsetinblock;
267 cd9660_rrip_getname(ep,altname,&namelen,&dp->i_ino,imp);
268 if (namelen == cnp->cn_namelen
269 && !bcmp(name,altname,namelen))
274 dp->i_offset += reclen;
275 entryoffsetinblock += reclen;
280 if (saveoffset != dp->i_offset) {
281 if (lblkno(imp, dp->i_offset) !=
282 lblkno(imp, saveoffset)) {
285 if ((error = cd9660_blkatoff(vdp,
286 (off_t)saveoffset, NULL, &bp)) != 0)
289 entryoffsetinblock = saveoffset & bmask;
290 ep = (struct iso_directory_record *)
291 ((char *)bp->b_data + entryoffsetinblock);
292 dp->i_offset = saveoffset;
298 * If we started in the middle of the directory and failed
299 * to find our target, we must check the beginning as well.
301 if (numdirpasses == 2) {
304 endsearch = dp->i_diroff;
311 * Insert name into cache (as non-existent) if appropriate.
313 if (cnp->cn_flags & CNP_MAKEENTRY)
314 cache_enter(vdp, NCPNULL, *vpp, cnp);
315 if (nameiop == NAMEI_CREATE || nameiop == NAMEI_RENAME)
320 if (numdirpasses == 2)
321 gd->gd_nchstats->ncs_pass2++;
324 * Found component in pathname.
325 * If the final component of path name, save information
326 * in the cache as to where the entry was found.
328 if ((flags & CNP_ISLASTCN) && nameiop == NAMEI_LOOKUP)
329 dp->i_diroff = dp->i_offset;
332 * Step through the translation in the name. We do not `iput' the
333 * directory because we may need it again if a symbolic link
334 * is relative to the current directory. Instead we save it
335 * unlocked as "pdp". We must get the target inode before unlocking
336 * the directory to insure that the inode will not be removed
337 * before we get it. We prevent deadlock by always fetching
338 * inodes from the root, moving down the directory tree. Thus
339 * when following backward pointers ".." we must unlock the
340 * parent directory before getting the requested directory.
341 * There is a potential race condition here if both the current
342 * and parent directories are removed before the `iget' for the
343 * inode associated with ".." returns. We hope that this occurs
344 * infrequently since we cannot avoid this race condition without
345 * implementing a sophisticated deadlock detection algorithm.
346 * Note also that this simple deadlock detection scheme will not
347 * work if the file system has any hard links other than ".."
348 * that point backwards in the directory structure.
352 * If ino is different from dp->i_ino,
353 * it's a relocated directory.
355 if (flags & CNP_ISDOTDOT) {
356 VOP_UNLOCK(pdp, NULL, 0, td); /* race to get the inode */
357 error = cd9660_vget_internal(vdp->v_mount, dp->i_ino, &tdp,
358 dp->i_ino != ino, ep);
361 vn_lock(pdp, NULL, LK_EXCLUSIVE | LK_RETRY, td);
364 if (lockparent && (flags & CNP_ISLASTCN)) {
365 if ((error = vn_lock(pdp, NULL, LK_EXCLUSIVE, td)) != 0) {
366 cnp->cn_flags |= CNP_PDIRUNLOCK;
371 cnp->cn_flags |= CNP_PDIRUNLOCK;
373 } else if (dp->i_number == dp->i_ino) {
375 VREF(vdp); /* we want ourself, ie "." */
378 error = cd9660_vget_internal(vdp->v_mount, dp->i_ino, &tdp,
379 dp->i_ino != ino, ep);
383 if (!lockparent || !(flags & CNP_ISLASTCN)) {
384 cnp->cn_flags |= CNP_PDIRUNLOCK;
385 VOP_UNLOCK(pdp, NULL, 0, td);
391 * Insert name into cache if appropriate.
393 if (cnp->cn_flags & CNP_MAKEENTRY)
394 cache_enter(vdp, NCPNULL, *vpp, cnp);
399 * Return buffer with the contents of block "offset" from the beginning of
400 * directory "ip". If "res" is non-zero, fill it in with a pointer to the
401 * remaining space in the directory.
404 cd9660_blkatoff(vp, offset, res, bpp)
418 lbn = lblkno(imp, offset);
419 bsize = blksize(imp, ip, lbn);
421 if ((error = bread(vp, lbn, bsize, &bp)) != 0) {
428 * We must BMAP the buffer because the directory code may use b_blkno
429 * to calculate the inode for certain types of directory entries.
430 * We could get away with not doing it before we VMIO-backed the
431 * directories because the buffers would get freed atomically with
432 * the invalidation of their data. But with VMIO-backed buffers
433 * the buffers may be freed and then later reconstituted - and the
434 * reconstituted buffer will have no knowledge of b_blkno.
436 if (bp->b_blkno == bp->b_lblkno) {
437 error = VOP_BMAP(vp, bp->b_lblkno, NULL,
438 &bp->b_blkno, NULL, NULL);
441 bp->b_flags |= B_ERROR;
449 *res = (char *)bp->b_data + blkoff(imp, offset);