1 | /* $NetBSD: cd9660_lookup.c,v 1.30 2015/03/28 19:24:05 maxv Exp $ */ |
2 | |
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 | * |
38 | * @(#)cd9660_lookup.c 8.5 (Berkeley) 5/27/95 |
39 | */ |
40 | |
41 | #include <sys/cdefs.h> |
42 | __KERNEL_RCSID(0, "$NetBSD: cd9660_lookup.c,v 1.30 2015/03/28 19:24:05 maxv Exp $" ); |
43 | |
44 | #include <sys/param.h> |
45 | #include <sys/namei.h> |
46 | #include <sys/buf.h> |
47 | #include <sys/file.h> |
48 | #include <sys/vnode.h> |
49 | #include <sys/mount.h> |
50 | #include <sys/systm.h> |
51 | #include <sys/kauth.h> |
52 | |
53 | #include <fs/cd9660/iso.h> |
54 | #include <fs/cd9660/cd9660_extern.h> |
55 | #include <fs/cd9660/cd9660_node.h> |
56 | #include <fs/cd9660/iso_rrip.h> |
57 | #include <fs/cd9660/cd9660_rrip.h> |
58 | #include <fs/cd9660/cd9660_mount.h> |
59 | |
60 | /* |
61 | * Convert a component of a pathname into a pointer to a locked inode. |
62 | * This is a very central and rather complicated routine. |
63 | * If the file system is not maintained in a strict tree hierarchy, |
64 | * this can result in a deadlock situation (see comments in code below). |
65 | * |
66 | * The flag argument is LOOKUP, CREATE, RENAME, or DELETE depending on |
67 | * whether the name is to be looked up, created, renamed, or deleted. |
68 | * When CREATE, RENAME, or DELETE is specified, information usable in |
69 | * creating, renaming, or deleting a directory entry may be calculated. |
70 | * If the target of the pathname exists, lookup returns both the target |
71 | * and its parent directory locked. |
72 | * When creating or renaming, the target may * not be ".". |
73 | * When deleting , the target may be "."., but the caller must check |
74 | * to ensure it does an vrele and vput instead of two vputs. |
75 | * |
76 | * Overall outline of ufs_lookup: |
77 | * |
78 | * check accessibility of directory |
79 | * look for name in cache, if found, then if at end of path |
80 | * and deleting or creating, drop it, else return name |
81 | * search for name in directory, to found or notfound |
82 | * notfound: |
83 | * if creating, return locked directory, leaving info on available slots |
84 | * else return error |
85 | * found: |
86 | * if at end of path and deleting, return information to allow delete |
87 | * if at end of path and rewriting (RENAME), lock target |
88 | * inode and return info to allow rewrite |
89 | * if not at end, add name to cache; if at end and neither creating |
90 | * nor deleting, add name to cache |
91 | */ |
92 | int |
93 | cd9660_lookup(void *v) |
94 | { |
95 | struct vop_lookup_v2_args /* { |
96 | struct vnode *a_dvp; |
97 | struct vnode **a_vpp; |
98 | struct componentname *a_cnp; |
99 | } */ *ap = v; |
100 | struct vnode *vdp; /* vnode for directory being searched */ |
101 | struct iso_node *dp; /* inode for directory being searched */ |
102 | struct iso_mnt *imp; /* file system that directory is in */ |
103 | struct buf *bp; /* a buffer of directory entries */ |
104 | struct iso_directory_record *ep = NULL; |
105 | /* the current directory entry */ |
106 | int entryoffsetinblock; /* offset of ep in bp's buffer */ |
107 | int saveoffset = -1; /* offset of last directory entry in dir */ |
108 | int numdirpasses; /* strategy for directory search */ |
109 | doff_t endsearch; /* offset to end directory search */ |
110 | struct vnode *tdp; /* returned by vcache_get */ |
111 | u_long bmask; /* block offset mask */ |
112 | int error; |
113 | ino_t ino = 0; |
114 | int reclen; |
115 | u_short namelen; |
116 | char altname[ISO_MAXNAMLEN]; |
117 | int res; |
118 | int assoc, len; |
119 | const char *name; |
120 | struct vnode **vpp = ap->a_vpp; |
121 | struct componentname *cnp = ap->a_cnp; |
122 | kauth_cred_t cred = cnp->cn_cred; |
123 | int flags; |
124 | int nameiop = cnp->cn_nameiop; |
125 | |
126 | flags = cnp->cn_flags; |
127 | |
128 | bp = NULL; |
129 | *vpp = NULL; |
130 | vdp = ap->a_dvp; |
131 | dp = VTOI(vdp); |
132 | imp = dp->i_mnt; |
133 | |
134 | /* |
135 | * Check accessiblity of directory. |
136 | */ |
137 | if ((error = VOP_ACCESS(vdp, VEXEC, cred)) != 0) |
138 | return (error); |
139 | |
140 | if ((flags & ISLASTCN) && (vdp->v_mount->mnt_flag & MNT_RDONLY) && |
141 | (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME)) |
142 | return (EROFS); |
143 | |
144 | /* |
145 | * We now have a segment name to search for, and a directory to search. |
146 | * |
147 | * Before tediously performing a linear scan of the directory, |
148 | * check the name cache to see if the directory/name pair |
149 | * we are looking for is known already. |
150 | */ |
151 | if (cache_lookup(vdp, cnp->cn_nameptr, cnp->cn_namelen, |
152 | cnp->cn_nameiop, cnp->cn_flags, NULL, vpp)) { |
153 | return *vpp == NULLVP ? ENOENT : 0; |
154 | } |
155 | |
156 | len = cnp->cn_namelen; |
157 | name = cnp->cn_nameptr; |
158 | /* |
159 | * A leading `=' means, we are looking for an associated file |
160 | */ |
161 | assoc = (imp->iso_ftype != ISO_FTYPE_RRIP && *name == ASSOCCHAR); |
162 | if (assoc) { |
163 | len--; |
164 | name++; |
165 | } |
166 | |
167 | /* |
168 | * If there is cached information on a previous search of |
169 | * this directory, pick up where we last left off. |
170 | * We cache only lookups as these are the most common |
171 | * and have the greatest payoff. Caching CREATE has little |
172 | * benefit as it usually must search the entire directory |
173 | * to determine that the entry does not exist. Caching the |
174 | * location of the last DELETE or RENAME has not reduced |
175 | * profiling time and hence has been removed in the interest |
176 | * of simplicity. |
177 | */ |
178 | bmask = imp->im_bmask; |
179 | if (nameiop != LOOKUP || dp->i_diroff == 0 || |
180 | dp->i_diroff > dp->i_size) { |
181 | entryoffsetinblock = 0; |
182 | dp->i_offset = 0; |
183 | numdirpasses = 1; |
184 | } else { |
185 | dp->i_offset = dp->i_diroff; |
186 | if ((entryoffsetinblock = dp->i_offset & bmask) && |
187 | (error = cd9660_blkatoff(vdp, (off_t)dp->i_offset, NULL, |
188 | &bp))) |
189 | return (error); |
190 | numdirpasses = 2; |
191 | namecache_count_2passes(); |
192 | } |
193 | endsearch = dp->i_size; |
194 | |
195 | searchloop: |
196 | while (dp->i_offset < endsearch) { |
197 | /* |
198 | * If offset is on a block boundary, |
199 | * read the next directory block. |
200 | * Release previous if it exists. |
201 | */ |
202 | if ((dp->i_offset & bmask) == 0) { |
203 | if (bp != NULL) |
204 | brelse(bp, 0); |
205 | error = cd9660_blkatoff(vdp, (off_t)dp->i_offset, |
206 | NULL, &bp); |
207 | if (error) |
208 | return (error); |
209 | entryoffsetinblock = 0; |
210 | } |
211 | /* |
212 | * Get pointer to next entry. |
213 | */ |
214 | KASSERT(bp != NULL); |
215 | ep = (struct iso_directory_record *) |
216 | ((char *)bp->b_data + entryoffsetinblock); |
217 | |
218 | reclen = isonum_711(ep->length); |
219 | if (reclen == 0) { |
220 | /* skip to next block, if any */ |
221 | dp->i_offset = |
222 | (dp->i_offset & ~bmask) + imp->logical_block_size; |
223 | continue; |
224 | } |
225 | |
226 | if (reclen < ISO_DIRECTORY_RECORD_SIZE) |
227 | /* illegal entry, stop */ |
228 | break; |
229 | |
230 | if (entryoffsetinblock + reclen > imp->logical_block_size) |
231 | /* entries are not allowed to cross boundaries */ |
232 | break; |
233 | |
234 | namelen = isonum_711(ep->name_len); |
235 | |
236 | if (reclen < ISO_DIRECTORY_RECORD_SIZE + namelen) |
237 | /* illegal entry, stop */ |
238 | break; |
239 | |
240 | /* |
241 | * Check for a name match. |
242 | */ |
243 | switch (imp->iso_ftype) { |
244 | default: |
245 | if ((!(isonum_711(ep->flags)&4)) == !assoc) { |
246 | if ((len == 1 |
247 | && *name == '.') |
248 | || (flags & ISDOTDOT)) { |
249 | if (namelen == 1 |
250 | && ep->name[0] == ((flags & ISDOTDOT) ? 1 : 0)) { |
251 | /* |
252 | * Save directory entry's inode number and |
253 | * release directory buffer. |
254 | */ |
255 | dp->i_ino = isodirino(ep, imp); |
256 | goto found; |
257 | } |
258 | if (namelen != 1 |
259 | || ep->name[0] != 0) |
260 | goto notfound; |
261 | } else if (!(res = isofncmp(name,len, |
262 | ep->name,namelen, |
263 | imp->im_joliet_level))) { |
264 | if (isonum_711(ep->flags)&2) |
265 | ino = isodirino(ep, imp); |
266 | else |
267 | ino = dbtob(bp->b_blkno) |
268 | + entryoffsetinblock; |
269 | saveoffset = dp->i_offset; |
270 | } else if (ino) |
271 | goto foundino; |
272 | #ifdef NOSORTBUG /* On some CDs directory entries are not sorted correctly */ |
273 | else if (res < 0) |
274 | goto notfound; |
275 | else if (res > 0 && numdirpasses == 2) |
276 | numdirpasses++; |
277 | #endif |
278 | } |
279 | break; |
280 | case ISO_FTYPE_RRIP: |
281 | if (isonum_711(ep->flags)&2) |
282 | ino = isodirino(ep, imp); |
283 | else |
284 | ino = dbtob(bp->b_blkno) + entryoffsetinblock; |
285 | dp->i_ino = ino; |
286 | cd9660_rrip_getname(ep,altname,&namelen,&dp->i_ino,imp); |
287 | if (namelen == cnp->cn_namelen) { |
288 | if (imp->im_flags & ISOFSMNT_RRCASEINS) { |
289 | if (strncasecmp(name, altname, namelen) == 0) |
290 | goto found; |
291 | } else { |
292 | if (memcmp(name, altname, namelen) == 0) |
293 | goto found; |
294 | } |
295 | } |
296 | ino = 0; |
297 | break; |
298 | } |
299 | dp->i_offset += reclen; |
300 | entryoffsetinblock += reclen; |
301 | } |
302 | if (ino) { |
303 | foundino: |
304 | dp->i_ino = ino; |
305 | if (saveoffset != dp->i_offset) { |
306 | if (cd9660_lblkno(imp, dp->i_offset) != |
307 | cd9660_lblkno(imp, saveoffset)) { |
308 | if (bp != NULL) |
309 | brelse(bp, 0); |
310 | if ((error = cd9660_blkatoff(vdp, |
311 | (off_t)saveoffset, NULL, &bp)) != 0) |
312 | return (error); |
313 | } |
314 | entryoffsetinblock = saveoffset & bmask; |
315 | ep = (struct iso_directory_record *) |
316 | ((char *)bp->b_data + entryoffsetinblock); |
317 | dp->i_offset = saveoffset; |
318 | } |
319 | goto found; |
320 | } |
321 | notfound: |
322 | /* |
323 | * If we started in the middle of the directory and failed |
324 | * to find our target, we must check the beginning as well. |
325 | */ |
326 | if (numdirpasses == 2) { |
327 | numdirpasses--; |
328 | dp->i_offset = 0; |
329 | endsearch = dp->i_diroff; |
330 | goto searchloop; |
331 | } |
332 | if (bp != NULL) |
333 | brelse(bp, 0); |
334 | |
335 | /* |
336 | * Insert name into cache (as non-existent) if appropriate. |
337 | */ |
338 | cache_enter(vdp, *vpp, cnp->cn_nameptr, cnp->cn_namelen, cnp->cn_flags); |
339 | return (nameiop == CREATE || nameiop == RENAME) ? EROFS : ENOENT; |
340 | |
341 | found: |
342 | if (numdirpasses == 2) |
343 | namecache_count_pass2(); |
344 | brelse(bp, 0); |
345 | |
346 | /* |
347 | * Found component in pathname. |
348 | * If the final component of path name, save information |
349 | * in the cache as to where the entry was found. |
350 | */ |
351 | if ((flags & ISLASTCN) && nameiop == LOOKUP) |
352 | dp->i_diroff = dp->i_offset; |
353 | |
354 | if (dp->i_number == dp->i_ino) { |
355 | vref(vdp); /* we want ourself, ie "." */ |
356 | *vpp = vdp; |
357 | } else { |
358 | error = vcache_get(vdp->v_mount, |
359 | &dp->i_ino, sizeof(dp->i_ino), &tdp); |
360 | if (error) |
361 | return (error); |
362 | *vpp = tdp; |
363 | } |
364 | |
365 | /* |
366 | * Insert name into cache if appropriate. |
367 | */ |
368 | cache_enter(vdp, *vpp, cnp->cn_nameptr, cnp->cn_namelen, cnp->cn_flags); |
369 | |
370 | return 0; |
371 | } |
372 | |
373 | /* |
374 | * Return buffer with the contents of block "offset" from the beginning of |
375 | * directory "ip". If "res" is non-zero, fill it in with a pointer to the |
376 | * remaining space in the directory. |
377 | */ |
378 | int |
379 | cd9660_blkatoff(struct vnode *vp, off_t offset, char **res, struct buf **bpp) |
380 | { |
381 | struct iso_node *ip; |
382 | struct iso_mnt *imp; |
383 | struct vnode *devvp; |
384 | struct buf *bp; |
385 | daddr_t lbn; |
386 | int bsize, error; |
387 | |
388 | ip = VTOI(vp); |
389 | imp = ip->i_mnt; |
390 | lbn = cd9660_lblkno(imp, offset); |
391 | bsize = cd9660_blksize(imp, ip, lbn); |
392 | |
393 | if ((error = VOP_BMAP(vp, lbn, &devvp, &lbn, NULL)) != 0) { |
394 | *bpp = NULL; |
395 | return error; |
396 | } |
397 | if ((error = bread(devvp, lbn, bsize, 0, &bp)) != 0) { |
398 | *bpp = NULL; |
399 | return (error); |
400 | } |
401 | if (res) |
402 | *res = (char *)bp->b_data + cd9660_blkoff(imp, offset); |
403 | *bpp = bp; |
404 | return (0); |
405 | } |
406 | |