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15637ed4 RG |
1 | /* |
2 | * Copyright (c) 1989 The Regents of the University of California. | |
3 | * All rights reserved. | |
4 | * | |
584fddaa JH |
5 | * Copyright (c) 1983 Atsushi Murai (amurai@spec.co.jp) |
6 | * All rights reserved for Rock Ridge Extension Support. | |
7 | * | |
15637ed4 RG |
8 | * Redistribution and use in source and binary forms, with or without |
9 | * modification, are permitted provided that the following conditions | |
10 | * are met: | |
11 | * 1. Redistributions of source code must retain the above copyright | |
12 | * notice, this list of conditions and the following disclaimer. | |
13 | * 2. Redistributions in binary form must reproduce the above copyright | |
14 | * notice, this list of conditions and the following disclaimer in the | |
15 | * documentation and/or other materials provided with the distribution. | |
16 | * 3. All advertising materials mentioning features or use of this software | |
17 | * must display the following acknowledgement: | |
18 | * This product includes software developed by the University of | |
19 | * California, Berkeley and its contributors. | |
20 | * 4. 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 | * | |
584fddaa | 36 | * from: @(#)ufs_lookup.c 7.33 (Berkeley) 5/19/91 |
dd18dc33 | 37 | * $Id: isofs_lookup.c,v 1.2 1993/07/20 03:27:28 jkh Exp $ |
15637ed4 RG |
38 | */ |
39 | ||
40 | #include "param.h" | |
dd18dc33 | 41 | #include "systm.h" |
15637ed4 RG |
42 | #include "namei.h" |
43 | #include "buf.h" | |
44 | #include "file.h" | |
45 | #include "vnode.h" | |
46 | #include "mount.h" | |
47 | ||
48 | #include "iso.h" | |
49 | #include "isofs_node.h" | |
584fddaa JH |
50 | #include "iso_rrip.h" |
51 | #include "isofs_rrip.h" | |
15637ed4 RG |
52 | |
53 | struct nchstats nchstats; | |
54 | ||
55 | /* | |
56 | * Convert a component of a pathname into a pointer to a locked inode. | |
57 | * This is a very central and rather complicated routine. | |
58 | * If the file system is not maintained in a strict tree hierarchy, | |
59 | * this can result in a deadlock situation (see comments in code below). | |
60 | * | |
61 | * The flag argument is LOOKUP, CREATE, RENAME, or DELETE depending on | |
62 | * whether the name is to be looked up, created, renamed, or deleted. | |
63 | * When CREATE, RENAME, or DELETE is specified, information usable in | |
64 | * creating, renaming, or deleting a directory entry may be calculated. | |
65 | * If flag has LOCKPARENT or'ed into it and the target of the pathname | |
66 | * exists, lookup returns both the target and its parent directory locked. | |
67 | * When creating or renaming and LOCKPARENT is specified, the target may | |
68 | * not be ".". When deleting and LOCKPARENT is specified, the target may | |
69 | * be "."., but the caller must check to ensure it does an vrele and iput | |
70 | * instead of two iputs. | |
71 | * | |
72 | * Overall outline of ufs_lookup: | |
73 | * | |
74 | * check accessibility of directory | |
75 | * look for name in cache, if found, then if at end of path | |
76 | * and deleting or creating, drop it, else return name | |
77 | * search for name in directory, to found or notfound | |
78 | * notfound: | |
79 | * if creating, return locked directory, leaving info on available slots | |
80 | * else return error | |
81 | * found: | |
82 | * if at end of path and deleting, return information to allow delete | |
83 | * if at end of path and rewriting (RENAME and LOCKPARENT), lock target | |
84 | * inode and return info to allow rewrite | |
85 | * if not at end, add name to cache; if at end and neither creating | |
86 | * nor deleting, add name to cache | |
87 | * | |
88 | * NOTE: (LOOKUP | LOCKPARENT) currently returns the parent inode unlocked. | |
89 | */ | |
90 | isofs_lookup(vdp, ndp, p) | |
91 | register struct vnode *vdp; | |
92 | register struct nameidata *ndp; | |
93 | struct proc *p; | |
94 | { | |
95 | register struct iso_node *dp; /* the directory we are searching */ | |
96 | register struct iso_mnt *imp; /* file system that directory is in */ | |
97 | struct buf *bp = 0; /* a buffer of directory entries */ | |
98 | register struct iso_directory_record *ep; | |
99 | /* the current directory entry */ | |
100 | int entryoffsetinblock; /* offset of ep in bp's buffer */ | |
101 | enum {NONE, COMPACT, FOUND} slotstatus; | |
102 | int slotoffset = -1; /* offset of area with free space */ | |
103 | int slotsize; /* size of area at slotoffset */ | |
104 | int slotfreespace; /* amount of space free in slot */ | |
105 | int slotneeded; /* size of the entry we're seeking */ | |
106 | int numdirpasses; /* strategy for directory search */ | |
107 | int endsearch; /* offset to end directory search */ | |
108 | struct iso_node *pdp; /* saved dp during symlink work */ | |
109 | struct iso_node *tdp; /* returned by iget */ | |
110 | int flag; /* LOOKUP, CREATE, RENAME, or DELETE */ | |
111 | int lockparent; /* 1 => lockparent flag is set */ | |
112 | int wantparent; /* 1 => wantparent or lockparent flag */ | |
113 | int error; | |
114 | ||
115 | int reclen; | |
116 | int namelen; | |
584fddaa JH |
117 | char altname[251]; |
118 | int i; | |
15637ed4 RG |
119 | |
120 | ndp->ni_dvp = vdp; | |
121 | ndp->ni_vp = NULL; | |
122 | dp = VTOI(vdp); | |
123 | imp = dp->i_mnt; | |
124 | lockparent = ndp->ni_nameiop & LOCKPARENT; | |
125 | flag = ndp->ni_nameiop & OPMASK; | |
126 | wantparent = ndp->ni_nameiop & (LOCKPARENT|WANTPARENT); | |
127 | ||
128 | /* | |
129 | * Check accessiblity of directory. | |
130 | */ | |
131 | if ((dp->iso_flags & 2) == 0) | |
132 | return (ENOTDIR); | |
133 | ||
134 | /* | |
135 | * We now have a segment name to search for, and a directory to search. | |
136 | * | |
137 | * Before tediously performing a linear scan of the directory, | |
138 | * check the name cache to see if the directory/name pair | |
139 | * we are looking for is known already. | |
140 | */ | |
141 | if (error = cache_lookup(ndp)) { | |
142 | int vpid; /* capability number of vnode */ | |
143 | ||
144 | if (error == ENOENT) | |
145 | return (error); | |
146 | #ifdef PARANOID | |
147 | if (vdp == ndp->ni_rdir && ndp->ni_isdotdot) | |
148 | panic("ufs_lookup: .. through root"); | |
149 | #endif | |
150 | /* | |
151 | * Get the next vnode in the path. | |
152 | * See comment below starting `Step through' for | |
153 | * an explaination of the locking protocol. | |
154 | */ | |
155 | pdp = dp; | |
156 | dp = VTOI(ndp->ni_vp); | |
157 | vdp = ndp->ni_vp; | |
158 | vpid = vdp->v_id; | |
159 | if (pdp == dp) { | |
160 | VREF(vdp); | |
161 | error = 0; | |
162 | } else if (ndp->ni_isdotdot) { | |
163 | ISO_IUNLOCK(pdp); | |
164 | error = vget(vdp); | |
165 | if (!error && lockparent && *ndp->ni_next == '\0') | |
166 | ISO_ILOCK(pdp); | |
167 | } else { | |
168 | error = vget(vdp); | |
169 | if (!lockparent || error || *ndp->ni_next != '\0') | |
170 | ISO_IUNLOCK(pdp); | |
171 | } | |
172 | /* | |
173 | * Check that the capability number did not change | |
174 | * while we were waiting for the lock. | |
175 | */ | |
176 | if (!error) { | |
177 | if (vpid == vdp->v_id) | |
178 | return (0); | |
179 | iso_iput(dp); | |
180 | if (lockparent && pdp != dp && *ndp->ni_next == '\0') | |
181 | ISO_IUNLOCK(pdp); | |
182 | } | |
183 | ISO_ILOCK(pdp); | |
184 | dp = pdp; | |
185 | vdp = ITOV(dp); | |
186 | ndp->ni_vp = NULL; | |
187 | } | |
188 | ||
189 | /* | |
190 | * If there is cached information on a previous search of | |
191 | * this directory, pick up where we last left off. | |
192 | * We cache only lookups as these are the most common | |
193 | * and have the greatest payoff. Caching CREATE has little | |
194 | * benefit as it usually must search the entire directory | |
195 | * to determine that the entry does not exist. Caching the | |
196 | * location of the last DELETE or RENAME has not reduced | |
197 | * profiling time and hence has been removed in the interest | |
198 | * of simplicity. | |
199 | */ | |
200 | if (flag != LOOKUP || dp->i_diroff == 0 || dp->i_diroff > dp->i_size) { | |
201 | ndp->ni_ufs.ufs_offset = 0; | |
202 | numdirpasses = 1; | |
203 | } else { | |
204 | ndp->ni_ufs.ufs_offset = dp->i_diroff; | |
205 | entryoffsetinblock = iso_blkoff(imp, ndp->ni_ufs.ufs_offset); | |
206 | if (entryoffsetinblock != 0) { | |
207 | if (error = iso_blkatoff(dp, ndp->ni_ufs.ufs_offset, | |
208 | (char **)0, &bp)) | |
209 | return (error); | |
210 | } | |
211 | numdirpasses = 2; | |
212 | nchstats.ncs_2passes++; | |
213 | } | |
214 | endsearch = roundup(dp->i_size, imp->logical_block_size); | |
215 | ||
216 | searchloop: | |
217 | while (ndp->ni_ufs.ufs_offset < endsearch) { | |
218 | /* | |
219 | * If offset is on a block boundary, | |
220 | * read the next directory block. | |
221 | * Release previous if it exists. | |
222 | */ | |
223 | if (iso_blkoff(imp, ndp->ni_ufs.ufs_offset) == 0) { | |
224 | if (bp != NULL) | |
225 | brelse(bp); | |
226 | if (error = iso_blkatoff(dp, ndp->ni_ufs.ufs_offset, | |
227 | (char **)0, &bp)) | |
228 | return (error); | |
229 | entryoffsetinblock = 0; | |
230 | } | |
231 | /* | |
232 | * Get pointer to next entry. | |
233 | */ | |
234 | ||
235 | ep = (struct iso_directory_record *) | |
236 | (bp->b_un.b_addr + entryoffsetinblock); | |
237 | ||
238 | reclen = isonum_711 (ep->length); | |
239 | if (reclen == 0) { | |
240 | /* skip to next block, if any */ | |
241 | ndp->ni_ufs.ufs_offset = | |
242 | roundup (ndp->ni_ufs.ufs_offset, | |
243 | imp->logical_block_size); | |
244 | continue; | |
245 | } | |
246 | ||
247 | if (reclen < sizeof (struct iso_directory_record)) | |
248 | /* illegal entry, stop */ | |
249 | break; | |
250 | ||
251 | /* 10 Aug 92*/ if (entryoffsetinblock + reclen -1 >= imp->logical_block_size) | |
252 | /* entries are not allowed to cross boundaries */ | |
253 | break; | |
254 | ||
255 | /* | |
256 | * Check for a name match. | |
257 | */ | |
258 | namelen = isonum_711 (ep->name_len); | |
259 | ||
260 | if (reclen < sizeof (struct iso_directory_record) + namelen) | |
261 | /* illegal entry, stop */ | |
262 | break; | |
263 | ||
584fddaa | 264 | if (namelen == 1 |
15637ed4 RG |
265 | && ((ndp->ni_namelen == 1 |
266 | && ndp->ni_ptr[0] == '.' | |
267 | && ep->name[0] == 0) | |
584fddaa | 268 | || (ndp->ni_isdotdot && ep->name[0] == 1))) { |
15637ed4 RG |
269 | /* |
270 | * Save directory entry's inode number and | |
271 | * reclen in ndp->ni_ufs area, and release | |
272 | * directory buffer. | |
273 | */ | |
274 | ndp->ni_ufs.ufs_ino = isonum_733 (ep->extent); | |
275 | brelse(bp); | |
276 | goto found; | |
584fddaa JH |
277 | } else { |
278 | switch ( imp->iso_ftype ) { | |
279 | case ISO_FTYPE_9660: | |
280 | if( ( namelen >= ndp->ni_namelen ) && | |
281 | ( isofncmp( ndp->ni_ptr, ndp->ni_namelen, ep->name, namelen ) ) ) { | |
282 | ndp->ni_ufs.ufs_ino = isonum_733 (ep->extent); | |
283 | brelse(bp); | |
284 | goto found; | |
285 | } | |
286 | break; | |
287 | case ISO_FTYPE_RRIP: | |
288 | isofs_rrip_getname( ep, altname, &namelen ); | |
289 | if ( ( namelen == ndp->ni_namelen ) && | |
290 | ( !bcmp( ndp->ni_ptr, altname, ndp->ni_namelen ) ) ) { | |
291 | ndp->ni_ufs.ufs_ino = isonum_733 (ep->extent); | |
292 | brelse(bp); | |
293 | goto found; | |
294 | } | |
295 | break; | |
296 | default: | |
297 | break; | |
298 | } | |
15637ed4 RG |
299 | } |
300 | ndp->ni_ufs.ufs_offset += reclen; | |
301 | entryoffsetinblock += reclen; | |
302 | } | |
303 | /* notfound: */ | |
304 | /* | |
305 | * If we started in the middle of the directory and failed | |
306 | * to find our target, we must check the beginning as well. | |
307 | */ | |
308 | if (numdirpasses == 2) { | |
309 | numdirpasses--; | |
310 | ndp->ni_ufs.ufs_offset = 0; | |
311 | endsearch = dp->i_diroff; | |
312 | goto searchloop; | |
313 | } | |
314 | if (bp != NULL) | |
315 | brelse(bp); | |
316 | /* | |
317 | * Insert name into cache (as non-existent) if appropriate. | |
318 | */ | |
319 | if (ndp->ni_makeentry) | |
320 | cache_enter(ndp); | |
321 | return (ENOENT); | |
322 | ||
323 | found: | |
324 | if (numdirpasses == 2) | |
325 | nchstats.ncs_pass2++; | |
326 | ||
327 | /* | |
328 | * Found component in pathname. | |
329 | * If the final component of path name, save information | |
330 | * in the cache as to where the entry was found. | |
331 | */ | |
332 | if (*ndp->ni_next == '\0' && flag == LOOKUP) | |
333 | dp->i_diroff = ndp->ni_ufs.ufs_offset; | |
334 | /* &~ (imp->logical_block_size - 1); */ | |
335 | ||
336 | /* | |
337 | * Step through the translation in the name. We do not `iput' the | |
338 | * directory because we may need it again if a symbolic link | |
339 | * is relative to the current directory. Instead we save it | |
340 | * unlocked as "pdp". We must get the target inode before unlocking | |
341 | * the directory to insure that the inode will not be removed | |
342 | * before we get it. We prevent deadlock by always fetching | |
343 | * inodes from the root, moving down the directory tree. Thus | |
344 | * when following backward pointers ".." we must unlock the | |
345 | * parent directory before getting the requested directory. | |
346 | * There is a potential race condition here if both the current | |
347 | * and parent directories are removed before the `iget' for the | |
348 | * inode associated with ".." returns. We hope that this occurs | |
349 | * infrequently since we cannot avoid this race condition without | |
350 | * implementing a sophisticated deadlock detection algorithm. | |
351 | * Note also that this simple deadlock detection scheme will not | |
352 | * work if the file system has any hard links other than ".." | |
353 | * that point backwards in the directory structure. | |
354 | */ | |
355 | pdp = dp; | |
356 | if (ndp->ni_isdotdot) { | |
357 | ISO_IUNLOCK(pdp); /* race to get the inode */ | |
358 | if (error = iso_iget(dp, ndp->ni_ufs.ufs_ino, &tdp, ep)) { | |
359 | ISO_ILOCK(pdp); | |
360 | return (error); | |
361 | } | |
362 | if (lockparent && *ndp->ni_next == '\0') | |
363 | ISO_ILOCK(pdp); | |
364 | ndp->ni_vp = ITOV(tdp); | |
365 | } else if (dp->i_number == ndp->ni_ufs.ufs_ino) { | |
366 | VREF(vdp); /* we want ourself, ie "." */ | |
367 | ndp->ni_vp = vdp; | |
368 | } else { | |
369 | if (error = iso_iget(dp, ndp->ni_ufs.ufs_ino, &tdp, ep)) | |
370 | return (error); | |
371 | if (!lockparent || *ndp->ni_next != '\0') | |
372 | ISO_IUNLOCK(pdp); | |
373 | ndp->ni_vp = ITOV(tdp); | |
374 | } | |
375 | ||
376 | /* | |
377 | * Insert name into cache if appropriate. | |
378 | */ | |
379 | if (ndp->ni_makeentry) | |
380 | cache_enter(ndp); | |
381 | return (0); | |
382 | } | |
383 | ||
384 | ||
385 | /* | |
386 | * Return buffer with contents of block "offset" | |
387 | * from the beginning of directory "ip". If "res" | |
388 | * is non-zero, fill it in with a pointer to the | |
389 | * remaining space in the directory. | |
390 | */ | |
391 | iso_blkatoff(ip, offset, res, bpp) | |
392 | struct iso_node *ip; | |
393 | off_t offset; | |
394 | char **res; | |
395 | struct buf **bpp; | |
396 | { | |
397 | register struct iso_mnt *imp = ip->i_mnt; | |
398 | daddr_t lbn = iso_lblkno (imp, offset); | |
399 | int bsize = iso_blksize (imp, ip, lbn); | |
400 | struct buf *bp; | |
401 | int error; | |
402 | ||
403 | *bpp = 0; | |
404 | if (error = bread(ITOV(ip), lbn, bsize, NOCRED, &bp)) { | |
405 | brelse(bp); | |
406 | return (error); | |
407 | } | |
408 | if (res) | |
409 | *res = bp->b_un.b_addr + iso_blkoff(imp, offset); | |
410 | *bpp = bp; | |
411 | ||
412 | return (0); | |
413 | } |