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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19 * must display the following acknowledgement:
20 * This product includes software developed by the University of
21 * California, Berkeley and its contributors.
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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 1.25 2008/06/19 23:27:39 dillon 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"
60 * Convert a component of a pathname into a pointer to a locked inode.
61 * This is a very central and rather complicated routine.
62 * If the file system is not maintained in a strict tree hierarchy,
63 * this can result in a deadlock situation (see comments in code below).
65 * The flag argument is LOOKUP, CREATE, RENAME, or DELETE depending on
66 * whether the name is to be looked up, created, renamed, or deleted.
67 * When CREATE, RENAME, or DELETE is specified, information usable in
68 * creating, renaming, or deleting a directory entry may be calculated.
69 * If flag has LOCKPARENT or'ed into it and the target of the pathname
70 * exists, lookup returns both the target and its parent directory locked.
71 * When creating or renaming and LOCKPARENT is specified, the target may
72 * not be ".". When deleting and LOCKPARENT is specified, the target may
73 * be "."., but the caller must check to ensure it does an vrele and iput
74 * instead of two iputs.
76 * Overall outline of ufs_lookup:
78 * search for name in directory, to found or notfound
80 * if creating, return locked directory, leaving info on available slots
83 * if at end of path and deleting, return information to allow delete
84 * if at end of path and rewriting (RENAME and LOCKPARENT), lock target
85 * inode and return info to allow rewrite
86 * if not at end, add name to cache; if at end and neither creating
87 * nor deleting, add name to cache
89 * NOTE: (LOOKUP | LOCKPARENT) currently returns the parent inode unlocked.
91 * cd9660_lookup(struct vnode *a_dvp, struct vnode **a_vpp,
92 * struct componentname *a_cnp)
95 cd9660_lookup(struct vop_old_lookup_args *ap)
97 struct vnode *vdp; /* vnode for directory being searched */
98 struct iso_node *dp; /* inode for directory being searched */
99 struct iso_mnt *imp; /* file system that directory is in */
100 struct buf *bp; /* a buffer of directory entries */
101 struct iso_directory_record *ep = 0;/* the current directory entry */
102 int entryoffsetinblock; /* offset of ep in bp's buffer */
103 int saveoffset = 0; /* offset of last directory entry in dir */
104 int numdirpasses; /* strategy for directory search */
105 doff_t endsearch; /* offset to end directory search */
106 struct vnode *pdp; /* saved dp during symlink work */
107 struct vnode *tdp; /* returned by cd9660_vget_internal */
108 u_long bmask; /* block offset mask */
109 int lockparent; /* 1 => lockparent flag is set */
110 int wantparent; /* 1 => wantparent or lockparent flag */
116 char altname[NAME_MAX];
120 struct vnode **vpp = ap->a_vpp;
121 struct componentname *cnp = ap->a_cnp;
122 int flags = cnp->cn_flags;
123 int nameiop = cnp->cn_nameiop;
130 lockparent = flags & CNP_LOCKPARENT;
131 wantparent = flags & (CNP_LOCKPARENT | CNP_WANTPARENT);
132 cnp->cn_flags &= ~CNP_PDIRUNLOCK;
135 * We now have a segment name to search for, and a directory to search.
138 len = cnp->cn_namelen;
139 name = cnp->cn_nameptr;
141 * A leading `=' means, we are looking for an associated file
143 if ((assoc = (imp->iso_ftype != ISO_FTYPE_RRIP && *name == ASSOCCHAR)))
150 * If there is cached information on a previous search of
151 * this directory, pick up where we last left off.
152 * We cache only lookups as these are the most common
153 * and have the greatest payoff. Caching CREATE has little
154 * benefit as it usually must search the entire directory
155 * to determine that the entry does not exist. Caching the
156 * location of the last DELETE or RENAME has not reduced
157 * profiling time and hence has been removed in the interest
160 bmask = imp->im_bmask;
161 if (nameiop != NAMEI_LOOKUP || dp->i_diroff == 0 ||
162 dp->i_diroff > dp->i_size) {
163 entryoffsetinblock = 0;
167 dp->i_offset = dp->i_diroff;
168 if ((entryoffsetinblock = dp->i_offset & bmask) &&
169 (error = cd9660_devblkatoff(vdp, (off_t)dp->i_offset, NULL, &bp)))
173 endsearch = dp->i_size;
176 while (dp->i_offset < endsearch) {
178 * If offset is on a block boundary,
179 * read the next directory block.
180 * Release previous if it exists.
182 if ((dp->i_offset & bmask) == 0) {
186 cd9660_devblkatoff(vdp, (off_t)dp->i_offset, NULL, &bp)) != 0)
188 entryoffsetinblock = 0;
191 * Get pointer to next entry.
193 ep = (struct iso_directory_record *)
194 ((char *)bp->b_data + entryoffsetinblock);
196 reclen = isonum_711(ep->length);
198 /* skip to next block, if any */
200 (dp->i_offset & ~bmask) + imp->logical_block_size;
204 if (reclen < ISO_DIRECTORY_RECORD_SIZE)
205 /* illegal entry, stop */
208 if (entryoffsetinblock + reclen > imp->logical_block_size)
209 /* entries are not allowed to cross boundaries */
212 namelen = isonum_711(ep->name_len);
213 isoflags = isonum_711(imp->iso_ftype == ISO_FTYPE_HIGH_SIERRA?
214 &ep->date[6]: ep->flags);
216 if (reclen < ISO_DIRECTORY_RECORD_SIZE + namelen)
217 /* illegal entry, stop */
221 * Check for a name match.
223 switch (imp->iso_ftype) {
225 if (!(isoflags & 4) == !assoc) {
228 || (flags & CNP_ISDOTDOT)) {
230 && ep->name[0] == ((flags & CNP_ISDOTDOT) ? 1 : 0)) {
232 * Save directory entry's inode number and
233 * release directory buffer.
235 dp->i_ino = isodirino(ep, imp);
241 } else if (!(res = isofncmp(name, len,
248 ino = isodirino(ep, imp);
250 ino = bp->b_bio1.bio_offset +
252 saveoffset = dp->i_offset;
255 #ifdef NOSORTBUG /* On some CDs directory entries are not sorted correctly */
258 else if (res > 0 && numdirpasses == 2)
264 if (isonum_711(ep->flags)&2)
265 ino = isodirino(ep, imp);
267 ino = bp->b_bio1.bio_offset +
270 cd9660_rrip_getname(ep,altname,&namelen,&dp->i_ino,imp);
271 if (namelen == cnp->cn_namelen
272 && !bcmp(name,altname,namelen))
277 dp->i_offset += reclen;
278 entryoffsetinblock += reclen;
283 if (saveoffset != dp->i_offset) {
284 if (lblkno(imp, dp->i_offset) !=
285 lblkno(imp, saveoffset)) {
288 if ((error = cd9660_devblkatoff(vdp,
289 (off_t)saveoffset, NULL, &bp)) != 0)
292 entryoffsetinblock = saveoffset & bmask;
293 ep = (struct iso_directory_record *)
294 ((char *)bp->b_data + entryoffsetinblock);
295 dp->i_offset = saveoffset;
301 * If we started in the middle of the directory and failed
302 * to find our target, we must check the beginning as well.
304 if (numdirpasses == 2) {
307 endsearch = dp->i_diroff;
313 if (nameiop == NAMEI_CREATE || nameiop == NAMEI_RENAME)
319 * Found component in pathname.
320 * If the final component of path name, save information
321 * in the cache as to where the entry was found.
323 if (nameiop == NAMEI_LOOKUP)
324 dp->i_diroff = dp->i_offset;
327 * Step through the translation in the name. We do not `iput' the
328 * directory because we may need it again if a symbolic link
329 * is relative to the current directory. Instead we save it
330 * unlocked as "pdp". We must get the target inode before unlocking
331 * the directory to insure that the inode will not be removed
332 * before we get it. We prevent deadlock by always fetching
333 * inodes from the root, moving down the directory tree. Thus
334 * when following backward pointers ".." we must unlock the
335 * parent directory before getting the requested directory.
336 * There is a potential race condition here if both the current
337 * and parent directories are removed before the `iget' for the
338 * inode associated with ".." returns. We hope that this occurs
339 * infrequently since we cannot avoid this race condition without
340 * implementing a sophisticated deadlock detection algorithm.
341 * Note also that this simple deadlock detection scheme will not
342 * work if the file system has any hard links other than ".."
343 * that point backwards in the directory structure.
347 * If ino is different from dp->i_ino,
348 * it's a relocated directory.
350 if (flags & CNP_ISDOTDOT) {
351 vn_unlock(pdp); /* race to get the inode */
352 error = cd9660_vget_internal(vdp->v_mount, dp->i_ino, &tdp,
353 dp->i_ino != ino, ep);
356 vn_lock(pdp, LK_EXCLUSIVE | LK_RETRY);
360 if ((error = vn_lock(pdp, LK_EXCLUSIVE)) != 0) {
361 cnp->cn_flags |= CNP_PDIRUNLOCK;
366 cnp->cn_flags |= CNP_PDIRUNLOCK;
368 } else if (dp->i_number == dp->i_ino) {
370 vref(vdp); /* we want ourself, ie "." */
373 error = cd9660_vget_internal(vdp->v_mount, dp->i_ino, &tdp,
374 dp->i_ino != ino, ep);
379 cnp->cn_flags |= CNP_PDIRUNLOCK;
388 * Return a buffer with the contents of block "offset" from the beginning of
389 * directory "ip". If "res" is non-zero, fill it in with a pointer to the
390 * remaining space in the directory.
393 cd9660_blkatoff(struct vnode *vp, off_t offset, char **res, struct buf **bpp)
403 lbn = lblkno(imp, offset);
404 bsize = blksize(imp, ip, lbn);
406 if ((error = bread(vp, lblktooff(imp, lbn), bsize, &bp)) != 0) {
413 * We must BMAP the buffer because the directory code may use
414 * bio_offset to calculate the inode for certain types of directory
415 * entries. We could get away with not doing it before we
416 * VMIO-backed the directories because the buffers would get freed
417 * atomically with the invalidation of their data. But with
418 * VMIO-backed buffers the buffers may be freed and then later
419 * reconstituted - and the reconstituted buffer will have no
420 * knowledge of bio_offset.
422 if (bp->b_bio2.bio_offset == NOOFFSET) {
423 error = VOP_BMAP(vp, bp->b_bio1.bio_offset,
424 &bp->b_bio2.bio_offset, NULL, NULL,
428 bp->b_flags |= B_ERROR;
436 *res = (char *)bp->b_data + blkoff(imp, offset);
443 * Return a buffer with the contents of block "offset" from the beginning of
444 * directory "ip". If "res" is non-zero, fill it in with a pointer to the
445 * remaining space in the directory.
447 * Use the underlying device vnode rather then the passed vnode for the
448 * buffer cache operation. This allows us to access meta-data conveniently
449 * without having to instantiate a VM object for the vnode.
451 * WARNING! Callers of this routine need to be careful when accessing
452 * the bio_offset. Since this is a device buffer, the device offset will
453 * be in bio1.bio_offset, not bio2.bio_offset.
456 cd9660_devblkatoff(struct vnode *vp, off_t offset, char **res, struct buf **bpp)
467 lbn = lblkno(imp, offset);
468 bsize = blksize(imp, ip, lbn);
470 error = VOP_BMAP(vp, lblktooff(imp, lbn), &doffset, NULL, NULL,
475 if ((error = bread(imp->im_devvp, doffset, bsize, &bp)) != 0) {
481 *res = (char *)bp->b_data + blkoff(imp, offset);