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a3e07024 WJ |
1 | /* |
2 | * Copyright (c) 1989 The Regents of the University of California. | |
3 | * All rights reserved. | |
4 | * | |
5 | * Redistribution and use in source and binary forms, with or without | |
6 | * modification, are permitted provided that the following conditions | |
7 | * are met: | |
8 | * 1. Redistributions of source code must retain the above copyright | |
9 | * notice, this list of conditions and the following disclaimer. | |
10 | * 2. Redistributions in binary form must reproduce the above copyright | |
11 | * notice, this list of conditions and the following disclaimer in the | |
12 | * documentation and/or other materials provided with the distribution. | |
13 | * 3. All advertising materials mentioning features or use of this software | |
14 | * must display the following acknowledgement: | |
15 | * This product includes software developed by the University of | |
16 | * California, Berkeley and its contributors. | |
17 | * 4. Neither the name of the University nor the names of its contributors | |
18 | * may be used to endorse or promote products derived from this software | |
19 | * without specific prior written permission. | |
20 | * | |
21 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND | |
22 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |
23 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE | |
24 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE | |
25 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL | |
26 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS | |
27 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) | |
28 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT | |
29 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY | |
30 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF | |
31 | * SUCH DAMAGE. | |
32 | * | |
33 | * @(#)ufs_lookup.c 7.33 (Berkeley) 5/19/91 | |
34 | */ | |
35 | ||
36 | #include "param.h" | |
37 | #include "namei.h" | |
38 | #include "buf.h" | |
39 | #include "file.h" | |
40 | #include "vnode.h" | |
41 | ||
42 | #include "quota.h" | |
43 | #include "inode.h" | |
44 | #include "dir.h" | |
45 | #include "fs.h" | |
46 | ||
47 | struct nchstats nchstats; | |
48 | #ifdef DIAGNOSTIC | |
49 | int dirchk = 1; | |
50 | #else | |
51 | int dirchk = 0; | |
52 | #endif | |
53 | ||
54 | /* | |
55 | * Convert a component of a pathname into a pointer to a locked inode. | |
56 | * This is a very central and rather complicated routine. | |
57 | * If the file system is not maintained in a strict tree hierarchy, | |
58 | * this can result in a deadlock situation (see comments in code below). | |
59 | * | |
60 | * The flag argument is LOOKUP, CREATE, RENAME, or DELETE depending on | |
61 | * whether the name is to be looked up, created, renamed, or deleted. | |
62 | * When CREATE, RENAME, or DELETE is specified, information usable in | |
63 | * creating, renaming, or deleting a directory entry may be calculated. | |
64 | * If flag has LOCKPARENT or'ed into it and the target of the pathname | |
65 | * exists, lookup returns both the target and its parent directory locked. | |
66 | * When creating or renaming and LOCKPARENT is specified, the target may | |
67 | * not be ".". When deleting and LOCKPARENT is specified, the target may | |
68 | * be "."., but the caller must check to ensure it does an vrele and iput | |
69 | * instead of two iputs. | |
70 | * | |
71 | * Overall outline of ufs_lookup: | |
72 | * | |
73 | * check accessibility of directory | |
74 | * look for name in cache, if found, then if at end of path | |
75 | * and deleting or creating, drop it, else return name | |
76 | * search for name in directory, to found or notfound | |
77 | * notfound: | |
78 | * if creating, return locked directory, leaving info on available slots | |
79 | * else return error | |
80 | * found: | |
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 | |
86 | * | |
87 | * NOTE: (LOOKUP | LOCKPARENT) currently returns the parent inode unlocked. | |
88 | */ | |
89 | ufs_lookup(vdp, ndp, p) | |
90 | register struct vnode *vdp; | |
91 | register struct nameidata *ndp; | |
92 | struct proc *p; | |
93 | { | |
94 | register struct inode *dp; /* the directory we are searching */ | |
95 | register struct fs *fs; /* file system that directory is in */ | |
96 | struct buf *bp = 0; /* a buffer of directory entries */ | |
97 | register struct direct *ep; /* the current directory entry */ | |
98 | int entryoffsetinblock; /* offset of ep in bp's buffer */ | |
99 | enum {NONE, COMPACT, FOUND} slotstatus; | |
100 | int slotoffset = -1; /* offset of area with free space */ | |
101 | int slotsize; /* size of area at slotoffset */ | |
102 | int slotfreespace; /* amount of space free in slot */ | |
103 | int slotneeded; /* size of the entry we're seeking */ | |
104 | int numdirpasses; /* strategy for directory search */ | |
105 | int endsearch; /* offset to end directory search */ | |
106 | int prevoff; /* ndp->ni_ufs.ufs_offset of previous entry */ | |
107 | struct inode *pdp; /* saved dp during symlink work */ | |
108 | struct inode *tdp; /* returned by iget */ | |
109 | off_t enduseful; /* pointer past last used dir slot */ | |
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 | ndp->ni_dvp = vdp; | |
116 | ndp->ni_vp = NULL; | |
117 | dp = VTOI(vdp); | |
118 | fs = dp->i_fs; | |
119 | lockparent = ndp->ni_nameiop & LOCKPARENT; | |
120 | flag = ndp->ni_nameiop & OPMASK; | |
121 | wantparent = ndp->ni_nameiop & (LOCKPARENT|WANTPARENT); | |
122 | ||
123 | /* | |
124 | * Check accessiblity of directory. | |
125 | */ | |
126 | if ((dp->i_mode&IFMT) != IFDIR) | |
127 | return (ENOTDIR); | |
128 | if (error = ufs_access(vdp, VEXEC, ndp->ni_cred, p)) | |
129 | return (error); | |
130 | ||
131 | /* | |
132 | * We now have a segment name to search for, and a directory to search. | |
133 | * | |
134 | * Before tediously performing a linear scan of the directory, | |
135 | * check the name cache to see if the directory/name pair | |
136 | * we are looking for is known already. | |
137 | */ | |
138 | if (error = cache_lookup(ndp)) { | |
139 | int vpid; /* capability number of vnode */ | |
140 | ||
141 | if (error == ENOENT) | |
142 | return (error); | |
143 | #ifdef PARANOID | |
144 | if (vdp == ndp->ni_rdir && ndp->ni_isdotdot) | |
145 | panic("ufs_lookup: .. through root"); | |
146 | #endif | |
147 | /* | |
148 | * Get the next vnode in the path. | |
149 | * See comment below starting `Step through' for | |
150 | * an explaination of the locking protocol. | |
151 | */ | |
152 | pdp = dp; | |
153 | dp = VTOI(ndp->ni_vp); | |
154 | vdp = ndp->ni_vp; | |
155 | vpid = vdp->v_id; | |
156 | if (pdp == dp) { | |
157 | VREF(vdp); | |
158 | error = 0; | |
159 | } else if (ndp->ni_isdotdot) { | |
160 | IUNLOCK(pdp); | |
161 | error = vget(vdp); | |
162 | if (!error && lockparent && *ndp->ni_next == '\0') | |
163 | ILOCK(pdp); | |
164 | } else { | |
165 | error = vget(vdp); | |
166 | if (!lockparent || error || *ndp->ni_next != '\0') | |
167 | IUNLOCK(pdp); | |
168 | } | |
169 | /* | |
170 | * Check that the capability number did not change | |
171 | * while we were waiting for the lock. | |
172 | */ | |
173 | if (!error) { | |
174 | if (vpid == vdp->v_id) | |
175 | return (0); | |
176 | iput(dp); | |
177 | if (lockparent && pdp != dp && *ndp->ni_next == '\0') | |
178 | IUNLOCK(pdp); | |
179 | } | |
180 | ILOCK(pdp); | |
181 | dp = pdp; | |
182 | vdp = ITOV(dp); | |
183 | ndp->ni_vp = NULL; | |
184 | } | |
185 | ||
186 | /* | |
187 | * Suppress search for slots unless creating | |
188 | * file and at end of pathname, in which case | |
189 | * we watch for a place to put the new file in | |
190 | * case it doesn't already exist. | |
191 | */ | |
192 | slotstatus = FOUND; | |
193 | if ((flag == CREATE || flag == RENAME) && *ndp->ni_next == 0) { | |
194 | slotstatus = NONE; | |
195 | slotfreespace = 0; | |
196 | slotneeded = ((sizeof (struct direct) - (MAXNAMLEN + 1)) + | |
197 | ((ndp->ni_namelen + 1 + 3) &~ 3)); | |
198 | } | |
199 | ||
200 | /* | |
201 | * If there is cached information on a previous search of | |
202 | * this directory, pick up where we last left off. | |
203 | * We cache only lookups as these are the most common | |
204 | * and have the greatest payoff. Caching CREATE has little | |
205 | * benefit as it usually must search the entire directory | |
206 | * to determine that the entry does not exist. Caching the | |
207 | * location of the last DELETE or RENAME has not reduced | |
208 | * profiling time and hence has been removed in the interest | |
209 | * of simplicity. | |
210 | */ | |
211 | if (flag != LOOKUP || dp->i_diroff == 0 || dp->i_diroff > dp->i_size) { | |
212 | ndp->ni_ufs.ufs_offset = 0; | |
213 | numdirpasses = 1; | |
214 | } else { | |
215 | ndp->ni_ufs.ufs_offset = dp->i_diroff; | |
216 | entryoffsetinblock = blkoff(fs, ndp->ni_ufs.ufs_offset); | |
217 | if (entryoffsetinblock != 0) { | |
218 | if (error = blkatoff(dp, ndp->ni_ufs.ufs_offset, | |
219 | (char **)0, &bp)) | |
220 | return (error); | |
221 | } | |
222 | numdirpasses = 2; | |
223 | nchstats.ncs_2passes++; | |
224 | } | |
225 | endsearch = roundup(dp->i_size, DIRBLKSIZ); | |
226 | enduseful = 0; | |
227 | ||
228 | searchloop: | |
229 | while (ndp->ni_ufs.ufs_offset < endsearch) { | |
230 | /* | |
231 | * If offset is on a block boundary, | |
232 | * read the next directory block. | |
233 | * Release previous if it exists. | |
234 | */ | |
235 | if (blkoff(fs, ndp->ni_ufs.ufs_offset) == 0) { | |
236 | if (bp != NULL) | |
237 | brelse(bp); | |
238 | if (error = blkatoff(dp, ndp->ni_ufs.ufs_offset, | |
239 | (char **)0, &bp)) | |
240 | return (error); | |
241 | entryoffsetinblock = 0; | |
242 | } | |
243 | /* | |
244 | * If still looking for a slot, and at a DIRBLKSIZE | |
245 | * boundary, have to start looking for free space again. | |
246 | */ | |
247 | if (slotstatus == NONE && | |
248 | (entryoffsetinblock & (DIRBLKSIZ - 1)) == 0) { | |
249 | slotoffset = -1; | |
250 | slotfreespace = 0; | |
251 | } | |
252 | /* | |
253 | * Get pointer to next entry. | |
254 | * Full validation checks are slow, so we only check | |
255 | * enough to insure forward progress through the | |
256 | * directory. Complete checks can be run by patching | |
257 | * "dirchk" to be true. | |
258 | */ | |
259 | ep = (struct direct *)(bp->b_un.b_addr + entryoffsetinblock); | |
260 | if (ep->d_reclen == 0 || | |
261 | dirchk && dirbadentry(ep, entryoffsetinblock)) { | |
262 | int i; | |
263 | ||
264 | dirbad(dp, ndp->ni_ufs.ufs_offset, "mangled entry"); | |
265 | i = DIRBLKSIZ - (entryoffsetinblock & (DIRBLKSIZ - 1)); | |
266 | ndp->ni_ufs.ufs_offset += i; | |
267 | entryoffsetinblock += i; | |
268 | continue; | |
269 | } | |
270 | ||
271 | /* | |
272 | * If an appropriate sized slot has not yet been found, | |
273 | * check to see if one is available. Also accumulate space | |
274 | * in the current block so that we can determine if | |
275 | * compaction is viable. | |
276 | */ | |
277 | if (slotstatus != FOUND) { | |
278 | int size = ep->d_reclen; | |
279 | ||
280 | if (ep->d_ino != 0) | |
281 | size -= DIRSIZ(ep); | |
282 | if (size > 0) { | |
283 | if (size >= slotneeded) { | |
284 | slotstatus = FOUND; | |
285 | slotoffset = ndp->ni_ufs.ufs_offset; | |
286 | slotsize = ep->d_reclen; | |
287 | } else if (slotstatus == NONE) { | |
288 | slotfreespace += size; | |
289 | if (slotoffset == -1) | |
290 | slotoffset = | |
291 | ndp->ni_ufs.ufs_offset; | |
292 | if (slotfreespace >= slotneeded) { | |
293 | slotstatus = COMPACT; | |
294 | slotsize = | |
295 | ndp->ni_ufs.ufs_offset + | |
296 | ep->d_reclen - slotoffset; | |
297 | } | |
298 | } | |
299 | } | |
300 | } | |
301 | ||
302 | /* | |
303 | * Check for a name match. | |
304 | */ | |
305 | if (ep->d_ino) { | |
306 | if (ep->d_namlen == ndp->ni_namelen && | |
307 | !bcmp(ndp->ni_ptr, ep->d_name, | |
308 | (unsigned)ep->d_namlen)) { | |
309 | /* | |
310 | * Save directory entry's inode number and | |
311 | * reclen in ndp->ni_ufs area, and release | |
312 | * directory buffer. | |
313 | */ | |
314 | ndp->ni_ufs.ufs_ino = ep->d_ino; | |
315 | ndp->ni_ufs.ufs_reclen = ep->d_reclen; | |
316 | goto found; | |
317 | } | |
318 | } | |
319 | prevoff = ndp->ni_ufs.ufs_offset; | |
320 | ndp->ni_ufs.ufs_offset += ep->d_reclen; | |
321 | entryoffsetinblock += ep->d_reclen; | |
322 | if (ep->d_ino) | |
323 | enduseful = ndp->ni_ufs.ufs_offset; | |
324 | } | |
325 | /* notfound: */ | |
326 | /* | |
327 | * If we started in the middle of the directory and failed | |
328 | * to find our target, we must check the beginning as well. | |
329 | */ | |
330 | if (numdirpasses == 2) { | |
331 | numdirpasses--; | |
332 | ndp->ni_ufs.ufs_offset = 0; | |
333 | endsearch = dp->i_diroff; | |
334 | goto searchloop; | |
335 | } | |
336 | if (bp != NULL) | |
337 | brelse(bp); | |
338 | /* | |
339 | * If creating, and at end of pathname and current | |
340 | * directory has not been removed, then can consider | |
341 | * allowing file to be created. | |
342 | */ | |
343 | if ((flag == CREATE || flag == RENAME) && | |
344 | *ndp->ni_next == 0 && dp->i_nlink != 0) { | |
345 | /* | |
346 | * Access for write is interpreted as allowing | |
347 | * creation of files in the directory. | |
348 | */ | |
349 | if (error = ufs_access(vdp, VWRITE, ndp->ni_cred, p)) | |
350 | return (error); | |
351 | /* | |
352 | * Return an indication of where the new directory | |
353 | * entry should be put. If we didn't find a slot, | |
354 | * then set ndp->ni_ufs.ufs_count to 0 indicating | |
355 | * that the new slot belongs at the end of the | |
356 | * directory. If we found a slot, then the new entry | |
357 | * can be put in the range from ndp->ni_ufs.ufs_offset | |
358 | * to ndp->ni_ufs.ufs_offset + ndp->ni_ufs.ufs_count. | |
359 | */ | |
360 | if (slotstatus == NONE) { | |
361 | ndp->ni_ufs.ufs_offset = roundup(dp->i_size, DIRBLKSIZ); | |
362 | ndp->ni_ufs.ufs_count = 0; | |
363 | enduseful = ndp->ni_ufs.ufs_offset; | |
364 | } else { | |
365 | ndp->ni_ufs.ufs_offset = slotoffset; | |
366 | ndp->ni_ufs.ufs_count = slotsize; | |
367 | if (enduseful < slotoffset + slotsize) | |
368 | enduseful = slotoffset + slotsize; | |
369 | } | |
370 | ndp->ni_ufs.ufs_endoff = roundup(enduseful, DIRBLKSIZ); | |
371 | dp->i_flag |= IUPD|ICHG; | |
372 | /* | |
373 | * We return with the directory locked, so that | |
374 | * the parameters we set up above will still be | |
375 | * valid if we actually decide to do a direnter(). | |
376 | * We return ni_vp == NULL to indicate that the entry | |
377 | * does not currently exist; we leave a pointer to | |
378 | * the (locked) directory inode in ndp->ni_dvp. | |
379 | * The pathname buffer is saved so that the name | |
380 | * can be obtained later. | |
381 | * | |
382 | * NB - if the directory is unlocked, then this | |
383 | * information cannot be used. | |
384 | */ | |
385 | ndp->ni_nameiop |= SAVENAME; | |
386 | if (!lockparent) | |
387 | IUNLOCK(dp); | |
388 | } | |
389 | /* | |
390 | * Insert name into cache (as non-existent) if appropriate. | |
391 | */ | |
392 | if (ndp->ni_makeentry && flag != CREATE) | |
393 | cache_enter(ndp); | |
394 | return (ENOENT); | |
395 | ||
396 | found: | |
397 | if (numdirpasses == 2) | |
398 | nchstats.ncs_pass2++; | |
399 | /* | |
400 | * Check that directory length properly reflects presence | |
401 | * of this entry. | |
402 | */ | |
403 | if (entryoffsetinblock + DIRSIZ(ep) > dp->i_size) { | |
404 | dirbad(dp, ndp->ni_ufs.ufs_offset, "i_size too small"); | |
405 | dp->i_size = entryoffsetinblock + DIRSIZ(ep); | |
406 | dp->i_flag |= IUPD|ICHG; | |
407 | } | |
408 | ||
409 | brelse(bp); | |
410 | ||
411 | /* | |
412 | * Found component in pathname. | |
413 | * If the final component of path name, save information | |
414 | * in the cache as to where the entry was found. | |
415 | */ | |
416 | if (*ndp->ni_next == '\0' && flag == LOOKUP) | |
417 | dp->i_diroff = ndp->ni_ufs.ufs_offset &~ (DIRBLKSIZ - 1); | |
418 | ||
419 | /* | |
420 | * If deleting, and at end of pathname, return | |
421 | * parameters which can be used to remove file. | |
422 | * If the wantparent flag isn't set, we return only | |
423 | * the directory (in ndp->ni_dvp), otherwise we go | |
424 | * on and lock the inode, being careful with ".". | |
425 | */ | |
426 | if (flag == DELETE && *ndp->ni_next == 0) { | |
427 | /* | |
428 | * Write access to directory required to delete files. | |
429 | */ | |
430 | if (error = ufs_access(vdp, VWRITE, ndp->ni_cred, p)) | |
431 | return (error); | |
432 | /* | |
433 | * Return pointer to current entry in ndp->ni_ufs.ufs_offset, | |
434 | * and distance past previous entry (if there | |
435 | * is a previous entry in this block) in ndp->ni_ufs.ufs_count. | |
436 | * Save directory inode pointer in ndp->ni_dvp for dirremove(). | |
437 | */ | |
438 | if ((ndp->ni_ufs.ufs_offset&(DIRBLKSIZ-1)) == 0) | |
439 | ndp->ni_ufs.ufs_count = 0; | |
440 | else | |
441 | ndp->ni_ufs.ufs_count = ndp->ni_ufs.ufs_offset - prevoff; | |
442 | if (dp->i_number == ndp->ni_ufs.ufs_ino) { | |
443 | VREF(vdp); | |
444 | ndp->ni_vp = vdp; | |
445 | return (0); | |
446 | } | |
447 | if (error = iget(dp, ndp->ni_ufs.ufs_ino, &tdp)) | |
448 | return (error); | |
449 | /* | |
450 | * If directory is "sticky", then user must own | |
451 | * the directory, or the file in it, else she | |
452 | * may not delete it (unless she's root). This | |
453 | * implements append-only directories. | |
454 | */ | |
455 | if ((dp->i_mode & ISVTX) && | |
456 | ndp->ni_cred->cr_uid != 0 && | |
457 | ndp->ni_cred->cr_uid != dp->i_uid && | |
458 | tdp->i_uid != ndp->ni_cred->cr_uid) { | |
459 | iput(tdp); | |
460 | return (EPERM); | |
461 | } | |
462 | ndp->ni_vp = ITOV(tdp); | |
463 | if (!lockparent) | |
464 | IUNLOCK(dp); | |
465 | return (0); | |
466 | } | |
467 | ||
468 | /* | |
469 | * If rewriting (RENAME), return the inode and the | |
470 | * information required to rewrite the present directory | |
471 | * Must get inode of directory entry to verify it's a | |
472 | * regular file, or empty directory. | |
473 | */ | |
474 | if (flag == RENAME && wantparent && *ndp->ni_next == 0) { | |
475 | if (error = ufs_access(vdp, VWRITE, ndp->ni_cred, p)) | |
476 | return (error); | |
477 | /* | |
478 | * Careful about locking second inode. | |
479 | * This can only occur if the target is ".". | |
480 | */ | |
481 | if (dp->i_number == ndp->ni_ufs.ufs_ino) | |
482 | return (EISDIR); | |
483 | if (error = iget(dp, ndp->ni_ufs.ufs_ino, &tdp)) | |
484 | return (error); | |
485 | ndp->ni_vp = ITOV(tdp); | |
486 | ndp->ni_nameiop |= SAVENAME; | |
487 | if (!lockparent) | |
488 | IUNLOCK(dp); | |
489 | return (0); | |
490 | } | |
491 | ||
492 | /* | |
493 | * Step through the translation in the name. We do not `iput' the | |
494 | * directory because we may need it again if a symbolic link | |
495 | * is relative to the current directory. Instead we save it | |
496 | * unlocked as "pdp". We must get the target inode before unlocking | |
497 | * the directory to insure that the inode will not be removed | |
498 | * before we get it. We prevent deadlock by always fetching | |
499 | * inodes from the root, moving down the directory tree. Thus | |
500 | * when following backward pointers ".." we must unlock the | |
501 | * parent directory before getting the requested directory. | |
502 | * There is a potential race condition here if both the current | |
503 | * and parent directories are removed before the `iget' for the | |
504 | * inode associated with ".." returns. We hope that this occurs | |
505 | * infrequently since we cannot avoid this race condition without | |
506 | * implementing a sophisticated deadlock detection algorithm. | |
507 | * Note also that this simple deadlock detection scheme will not | |
508 | * work if the file system has any hard links other than ".." | |
509 | * that point backwards in the directory structure. | |
510 | */ | |
511 | pdp = dp; | |
512 | if (ndp->ni_isdotdot) { | |
513 | IUNLOCK(pdp); /* race to get the inode */ | |
514 | if (error = iget(dp, ndp->ni_ufs.ufs_ino, &tdp)) { | |
515 | ILOCK(pdp); | |
516 | return (error); | |
517 | } | |
518 | if (lockparent && *ndp->ni_next == '\0') | |
519 | ILOCK(pdp); | |
520 | ndp->ni_vp = ITOV(tdp); | |
521 | } else if (dp->i_number == ndp->ni_ufs.ufs_ino) { | |
522 | VREF(vdp); /* we want ourself, ie "." */ | |
523 | ndp->ni_vp = vdp; | |
524 | } else { | |
525 | if (error = iget(dp, ndp->ni_ufs.ufs_ino, &tdp)) | |
526 | return (error); | |
527 | if (!lockparent || *ndp->ni_next != '\0') | |
528 | IUNLOCK(pdp); | |
529 | ndp->ni_vp = ITOV(tdp); | |
530 | } | |
531 | ||
532 | /* | |
533 | * Insert name into cache if appropriate. | |
534 | */ | |
535 | if (ndp->ni_makeentry) | |
536 | cache_enter(ndp); | |
537 | return (0); | |
538 | } | |
539 | ||
540 | ||
541 | dirbad(ip, offset, how) | |
542 | struct inode *ip; | |
543 | off_t offset; | |
544 | char *how; | |
545 | { | |
546 | ||
547 | printf("%s: bad dir ino %d at offset %d: %s\n", | |
548 | ip->i_fs->fs_fsmnt, ip->i_number, offset, how); | |
549 | if (ip->i_fs->fs_ronly == 0) | |
550 | panic("bad dir"); | |
551 | } | |
552 | ||
553 | /* | |
554 | * Do consistency checking on a directory entry: | |
555 | * record length must be multiple of 4 | |
556 | * entry must fit in rest of its DIRBLKSIZ block | |
557 | * record must be large enough to contain entry | |
558 | * name is not longer than MAXNAMLEN | |
559 | * name must be as long as advertised, and null terminated | |
560 | */ | |
561 | dirbadentry(ep, entryoffsetinblock) | |
562 | register struct direct *ep; | |
563 | int entryoffsetinblock; | |
564 | { | |
565 | register int i; | |
566 | ||
567 | if ((ep->d_reclen & 0x3) != 0 || | |
568 | ep->d_reclen > DIRBLKSIZ - (entryoffsetinblock & (DIRBLKSIZ - 1)) || | |
569 | ep->d_reclen < DIRSIZ(ep) || ep->d_namlen > MAXNAMLEN) | |
570 | return (1); | |
571 | for (i = 0; i < ep->d_namlen; i++) | |
572 | if (ep->d_name[i] == '\0') | |
573 | return (1); | |
574 | return (ep->d_name[i]); | |
575 | } | |
576 | ||
577 | /* | |
578 | * Write a directory entry after a call to namei, using the parameters | |
579 | * that it left in nameidata. The argument ip is the inode which the new | |
580 | * directory entry will refer to. The nameidata field ndp->ni_dvp is a | |
581 | * pointer to the directory to be written, which was left locked by namei. | |
582 | * Remaining parameters (ndp->ni_ufs.ufs_offset, ndp->ni_ufs.ufs_count) | |
583 | * indicate how the space for the new entry is to be obtained. | |
584 | */ | |
585 | direnter(ip, ndp) | |
586 | struct inode *ip; | |
587 | register struct nameidata *ndp; | |
588 | { | |
589 | register struct direct *ep, *nep; | |
590 | register struct inode *dp = VTOI(ndp->ni_dvp); | |
591 | struct buf *bp; | |
592 | int loc, spacefree, error = 0; | |
593 | u_int dsize; | |
594 | int newentrysize; | |
595 | char *dirbuf; | |
596 | struct uio auio; | |
597 | struct iovec aiov; | |
598 | struct direct newdir; | |
599 | ||
600 | #ifdef DIAGNOSTIC | |
601 | if ((ndp->ni_nameiop & SAVENAME) == 0) | |
602 | panic("direnter: missing name"); | |
603 | #endif | |
604 | newdir.d_ino = ip->i_number; | |
605 | newdir.d_namlen = ndp->ni_namelen; | |
606 | bcopy(ndp->ni_ptr, newdir.d_name, (unsigned)ndp->ni_namelen + 1); | |
607 | newentrysize = DIRSIZ(&newdir); | |
608 | if (ndp->ni_ufs.ufs_count == 0) { | |
609 | /* | |
610 | * If ndp->ni_ufs.ufs_count is 0, then namei could find no | |
611 | * space in the directory. Here, ndp->ni_ufs.ufs_offset will | |
612 | * be on a directory block boundary and we will write the | |
613 | * new entry into a fresh block. | |
614 | */ | |
615 | if (ndp->ni_ufs.ufs_offset & (DIRBLKSIZ - 1)) | |
616 | panic("wdir: newblk"); | |
617 | auio.uio_offset = ndp->ni_ufs.ufs_offset; | |
618 | newdir.d_reclen = DIRBLKSIZ; | |
619 | auio.uio_resid = newentrysize; | |
620 | aiov.iov_len = newentrysize; | |
621 | aiov.iov_base = (caddr_t)&newdir; | |
622 | auio.uio_iov = &aiov; | |
623 | auio.uio_iovcnt = 1; | |
624 | auio.uio_rw = UIO_WRITE; | |
625 | auio.uio_segflg = UIO_SYSSPACE; | |
626 | auio.uio_procp = (struct proc *)0; | |
627 | error = ufs_write(ndp->ni_dvp, &auio, IO_SYNC, ndp->ni_cred); | |
628 | if (DIRBLKSIZ > dp->i_fs->fs_fsize) { | |
629 | panic("wdir: blksize"); /* XXX - should grow w/balloc */ | |
630 | } else if (!error) { | |
631 | dp->i_size = roundup(dp->i_size, DIRBLKSIZ); | |
632 | dp->i_flag |= ICHG; | |
633 | } | |
634 | return (error); | |
635 | } | |
636 | ||
637 | /* | |
638 | * If ndp->ni_ufs.ufs_count is non-zero, then namei found space | |
639 | * for the new entry in the range ndp->ni_ufs.ufs_offset to | |
640 | * ndp->ni_ufs.ufs_offset + ndp->ni_ufs.ufs_count in the directory. | |
641 | * To use this space, we may have to compact the entries located | |
642 | * there, by copying them together towards the beginning of the | |
643 | * block, leaving the free space in one usable chunk at the end. | |
644 | */ | |
645 | ||
646 | /* | |
647 | * Increase size of directory if entry eats into new space. | |
648 | * This should never push the size past a new multiple of | |
649 | * DIRBLKSIZE. | |
650 | * | |
651 | * N.B. - THIS IS AN ARTIFACT OF 4.2 AND SHOULD NEVER HAPPEN. | |
652 | */ | |
653 | if (ndp->ni_ufs.ufs_offset + ndp->ni_ufs.ufs_count > dp->i_size) | |
654 | dp->i_size = ndp->ni_ufs.ufs_offset + ndp->ni_ufs.ufs_count; | |
655 | /* | |
656 | * Get the block containing the space for the new directory entry. | |
657 | */ | |
658 | if (error = blkatoff(dp, ndp->ni_ufs.ufs_offset, (char **)&dirbuf, &bp)) | |
659 | return (error); | |
660 | /* | |
661 | * Find space for the new entry. In the simple case, the entry at | |
662 | * offset base will have the space. If it does not, then namei | |
663 | * arranged that compacting the region ndp->ni_ufs.ufs_offset to | |
664 | * ndp->ni_ufs.ufs_offset + ndp->ni_ufs.ufs_count would yield the | |
665 | * space. | |
666 | */ | |
667 | ep = (struct direct *)dirbuf; | |
668 | dsize = DIRSIZ(ep); | |
669 | spacefree = ep->d_reclen - dsize; | |
670 | for (loc = ep->d_reclen; loc < ndp->ni_ufs.ufs_count; ) { | |
671 | nep = (struct direct *)(dirbuf + loc); | |
672 | if (ep->d_ino) { | |
673 | /* trim the existing slot */ | |
674 | ep->d_reclen = dsize; | |
675 | ep = (struct direct *)((char *)ep + dsize); | |
676 | } else { | |
677 | /* overwrite; nothing there; header is ours */ | |
678 | spacefree += dsize; | |
679 | } | |
680 | dsize = DIRSIZ(nep); | |
681 | spacefree += nep->d_reclen - dsize; | |
682 | loc += nep->d_reclen; | |
683 | bcopy((caddr_t)nep, (caddr_t)ep, dsize); | |
684 | } | |
685 | /* | |
686 | * Update the pointer fields in the previous entry (if any), | |
687 | * copy in the new entry, and write out the block. | |
688 | */ | |
689 | if (ep->d_ino == 0) { | |
690 | if (spacefree + dsize < newentrysize) | |
691 | panic("wdir: compact1"); | |
692 | newdir.d_reclen = spacefree + dsize; | |
693 | } else { | |
694 | if (spacefree < newentrysize) | |
695 | panic("wdir: compact2"); | |
696 | newdir.d_reclen = spacefree; | |
697 | ep->d_reclen = dsize; | |
698 | ep = (struct direct *)((char *)ep + dsize); | |
699 | } | |
700 | bcopy((caddr_t)&newdir, (caddr_t)ep, (u_int)newentrysize); | |
701 | error = bwrite(bp); | |
702 | dp->i_flag |= IUPD|ICHG; | |
703 | if (!error && ndp->ni_ufs.ufs_endoff && | |
704 | ndp->ni_ufs.ufs_endoff < dp->i_size) | |
705 | error = itrunc(dp, (u_long)ndp->ni_ufs.ufs_endoff, IO_SYNC); | |
706 | return (error); | |
707 | } | |
708 | ||
709 | /* | |
710 | * Remove a directory entry after a call to namei, using | |
711 | * the parameters which it left in nameidata. The entry | |
712 | * ni_ufs.ufs_offset contains the offset into the directory of the | |
713 | * entry to be eliminated. The ni_ufs.ufs_count field contains the | |
714 | * size of the previous record in the directory. If this | |
715 | * is 0, the first entry is being deleted, so we need only | |
716 | * zero the inode number to mark the entry as free. If the | |
717 | * entry is not the first in the directory, we must reclaim | |
718 | * the space of the now empty record by adding the record size | |
719 | * to the size of the previous entry. | |
720 | */ | |
721 | dirremove(ndp) | |
722 | register struct nameidata *ndp; | |
723 | { | |
724 | register struct inode *dp = VTOI(ndp->ni_dvp); | |
725 | struct direct *ep; | |
726 | struct buf *bp; | |
727 | int error; | |
728 | ||
729 | if (ndp->ni_ufs.ufs_count == 0) { | |
730 | /* | |
731 | * First entry in block: set d_ino to zero. | |
732 | */ | |
733 | error = blkatoff(dp, ndp->ni_ufs.ufs_offset, (char **)&ep, &bp); | |
734 | if (error) | |
735 | return (error); | |
736 | ep->d_ino = 0; | |
737 | error = bwrite(bp); | |
738 | dp->i_flag |= IUPD|ICHG; | |
739 | return (error); | |
740 | } | |
741 | /* | |
742 | * Collapse new free space into previous entry. | |
743 | */ | |
744 | if (error = blkatoff(dp, ndp->ni_ufs.ufs_offset - ndp->ni_ufs.ufs_count, | |
745 | (char **)&ep, &bp)) { | |
746 | return (error); | |
747 | } | |
748 | ep->d_reclen += ndp->ni_ufs.ufs_reclen; | |
749 | error = bwrite(bp); | |
750 | dp->i_flag |= IUPD|ICHG; | |
751 | return (error); | |
752 | } | |
753 | ||
754 | /* | |
755 | * Rewrite an existing directory entry to point at the inode | |
756 | * supplied. The parameters describing the directory entry are | |
757 | * set up by a call to namei. | |
758 | */ | |
759 | dirrewrite(dp, ip, ndp) | |
760 | struct inode *dp, *ip; | |
761 | struct nameidata *ndp; | |
762 | { | |
763 | struct direct *ep; | |
764 | struct buf *bp; | |
765 | int error; | |
766 | ||
767 | if (error = blkatoff(dp, ndp->ni_ufs.ufs_offset, (char **)&ep, &bp)) | |
768 | return (error); | |
769 | ep->d_ino = ip->i_number; | |
770 | error = bwrite(bp); | |
771 | dp->i_flag |= IUPD|ICHG; | |
772 | return (error); | |
773 | } | |
774 | ||
775 | /* | |
776 | * Return buffer with contents of block "offset" | |
777 | * from the beginning of directory "ip". If "res" | |
778 | * is non-zero, fill it in with a pointer to the | |
779 | * remaining space in the directory. | |
780 | */ | |
781 | blkatoff(ip, offset, res, bpp) | |
782 | struct inode *ip; | |
783 | off_t offset; | |
784 | char **res; | |
785 | struct buf **bpp; | |
786 | { | |
787 | register struct fs *fs = ip->i_fs; | |
788 | daddr_t lbn = lblkno(fs, offset); | |
789 | int bsize = blksize(fs, ip, lbn); | |
790 | struct buf *bp; | |
791 | daddr_t bn; | |
792 | int error; | |
793 | ||
794 | *bpp = 0; | |
795 | if (error = bread(ITOV(ip), lbn, bsize, NOCRED, &bp)) { | |
796 | brelse(bp); | |
797 | return (error); | |
798 | } | |
799 | if (res) | |
800 | *res = bp->b_un.b_addr + blkoff(fs, offset); | |
801 | *bpp = bp; | |
802 | return (0); | |
803 | } | |
804 | ||
805 | /* | |
806 | * Check if a directory is empty or not. | |
807 | * Inode supplied must be locked. | |
808 | * | |
809 | * Using a struct dirtemplate here is not precisely | |
810 | * what we want, but better than using a struct direct. | |
811 | * | |
812 | * NB: does not handle corrupted directories. | |
813 | */ | |
814 | dirempty(ip, parentino, cred) | |
815 | register struct inode *ip; | |
816 | ino_t parentino; | |
817 | struct ucred *cred; | |
818 | { | |
819 | register off_t off; | |
820 | struct dirtemplate dbuf; | |
821 | register struct direct *dp = (struct direct *)&dbuf; | |
822 | int error, count; | |
823 | #define MINDIRSIZ (sizeof (struct dirtemplate) / 2) | |
824 | ||
825 | for (off = 0; off < ip->i_size; off += dp->d_reclen) { | |
826 | error = vn_rdwr(UIO_READ, ITOV(ip), (caddr_t)dp, MINDIRSIZ, off, | |
827 | UIO_SYSSPACE, IO_NODELOCKED, cred, &count, (struct proc *)0); | |
828 | /* | |
829 | * Since we read MINDIRSIZ, residual must | |
830 | * be 0 unless we're at end of file. | |
831 | */ | |
832 | if (error || count != 0) | |
833 | return (0); | |
834 | /* avoid infinite loops */ | |
835 | if (dp->d_reclen == 0) | |
836 | return (0); | |
837 | /* skip empty entries */ | |
838 | if (dp->d_ino == 0) | |
839 | continue; | |
840 | /* accept only "." and ".." */ | |
841 | if (dp->d_namlen > 2) | |
842 | return (0); | |
843 | if (dp->d_name[0] != '.') | |
844 | return (0); | |
845 | /* | |
846 | * At this point d_namlen must be 1 or 2. | |
847 | * 1 implies ".", 2 implies ".." if second | |
848 | * char is also "." | |
849 | */ | |
850 | if (dp->d_namlen == 1) | |
851 | continue; | |
852 | if (dp->d_name[1] == '.' && dp->d_ino == parentino) | |
853 | continue; | |
854 | return (0); | |
855 | } | |
856 | return (1); | |
857 | } | |
858 | ||
859 | /* | |
860 | * Check if source directory is in the path of the target directory. | |
861 | * Target is supplied locked, source is unlocked. | |
862 | * The target is always iput() before returning. | |
863 | */ | |
864 | checkpath(source, target, cred) | |
865 | struct inode *source, *target; | |
866 | struct ucred *cred; | |
867 | { | |
868 | struct dirtemplate dirbuf; | |
869 | struct inode *ip; | |
870 | int error = 0; | |
871 | ||
872 | ip = target; | |
873 | if (ip->i_number == source->i_number) { | |
874 | error = EEXIST; | |
875 | goto out; | |
876 | } | |
877 | if (ip->i_number == ROOTINO) | |
878 | goto out; | |
879 | ||
880 | for (;;) { | |
881 | if ((ip->i_mode&IFMT) != IFDIR) { | |
882 | error = ENOTDIR; | |
883 | break; | |
884 | } | |
885 | error = vn_rdwr(UIO_READ, ITOV(ip), (caddr_t)&dirbuf, | |
886 | sizeof (struct dirtemplate), (off_t)0, UIO_SYSSPACE, | |
887 | IO_NODELOCKED, cred, (int *)0, (struct proc *)0); | |
888 | if (error != 0) | |
889 | break; | |
890 | if (dirbuf.dotdot_namlen != 2 || | |
891 | dirbuf.dotdot_name[0] != '.' || | |
892 | dirbuf.dotdot_name[1] != '.') { | |
893 | error = ENOTDIR; | |
894 | break; | |
895 | } | |
896 | if (dirbuf.dotdot_ino == source->i_number) { | |
897 | error = EINVAL; | |
898 | break; | |
899 | } | |
900 | if (dirbuf.dotdot_ino == ROOTINO) | |
901 | break; | |
902 | iput(ip); | |
903 | if (error = iget(ip, dirbuf.dotdot_ino, &ip)) | |
904 | break; | |
905 | } | |
906 | ||
907 | out: | |
908 | if (error == ENOTDIR) | |
909 | printf("checkpath: .. not a directory\n"); | |
910 | if (ip != NULL) | |
911 | iput(ip); | |
912 | return (error); | |
913 | } |