FreeBSD/Linux Kernel Cross Reference
sys/kern/vfs_lookup.c
1 /*
2 * Copyright (c) 1982, 1986, 1989, 1993
3 * The Regents of the University of California. All rights reserved.
4 * (c) UNIX System Laboratories, Inc.
5 * All or some portions of this file are derived from material licensed
6 * to the University of California by American Telephone and Telegraph
7 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
8 * the permission of UNIX System Laboratories, Inc.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 3. All advertising materials mentioning features or use of this software
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
24 * without specific prior written permission.
25 *
26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36 * SUCH DAMAGE.
37 *
38 * @(#)vfs_lookup.c 8.4 (Berkeley) 2/16/94
39 * $FreeBSD$
40 */
41
42 #include "opt_ktrace.h"
43
44 #include <sys/param.h>
45 #include <sys/systm.h>
46 #include <sys/namei.h>
47 #include <sys/vnode.h>
48 #include <sys/mount.h>
49 #include <sys/filedesc.h>
50 #include <sys/proc.h>
51
52 #ifdef KTRACE
53 #include <sys/ktrace.h>
54 #endif
55
56 #include <vm/vm_zone.h>
57
58 /*
59 * Convert a pathname into a pointer to a locked inode.
60 *
61 * The FOLLOW flag is set when symbolic links are to be followed
62 * when they occur at the end of the name translation process.
63 * Symbolic links are always followed for all other pathname
64 * components other than the last.
65 *
66 * The segflg defines whether the name is to be copied from user
67 * space or kernel space.
68 *
69 * Overall outline of namei:
70 *
71 * copy in name
72 * get starting directory
73 * while (!done && !error) {
74 * call lookup to search path.
75 * if symbolic link, massage name in buffer and continue
76 * }
77 */
78 int
79 namei(ndp)
80 register struct nameidata *ndp;
81 {
82 register struct filedesc *fdp; /* pointer to file descriptor state */
83 register char *cp; /* pointer into pathname argument */
84 register struct vnode *dp; /* the directory we are searching */
85 struct iovec aiov; /* uio for reading symbolic links */
86 struct uio auio;
87 int error, linklen;
88 struct componentname *cnp = &ndp->ni_cnd;
89 struct proc *p = cnp->cn_proc;
90
91 ndp->ni_cnd.cn_cred = ndp->ni_cnd.cn_proc->p_ucred;
92 KASSERT(cnp->cn_cred && cnp->cn_proc, ("namei: bad cred/proc"));
93 KASSERT((cnp->cn_nameiop & (~OPMASK)) == 0,
94 ("namei: nameiop contaminated with flags"));
95 KASSERT((cnp->cn_flags & OPMASK) == 0,
96 ("namei: flags contaminated with nameiops"));
97 fdp = cnp->cn_proc->p_fd;
98
99 /*
100 * Get a buffer for the name to be translated, and copy the
101 * name into the buffer.
102 */
103 if ((cnp->cn_flags & HASBUF) == 0)
104 cnp->cn_pnbuf = zalloc(namei_zone);
105 if (ndp->ni_segflg == UIO_SYSSPACE)
106 error = copystr(ndp->ni_dirp, cnp->cn_pnbuf,
107 MAXPATHLEN, (size_t *)&ndp->ni_pathlen);
108 else
109 error = copyinstr(ndp->ni_dirp, cnp->cn_pnbuf,
110 MAXPATHLEN, (size_t *)&ndp->ni_pathlen);
111
112 /*
113 * Don't allow empty pathnames.
114 */
115 if (!error && *cnp->cn_pnbuf == '\0')
116 error = ENOENT;
117
118 if (error) {
119 zfree(namei_zone, cnp->cn_pnbuf);
120 ndp->ni_vp = NULL;
121 return (error);
122 }
123 ndp->ni_loopcnt = 0;
124 #ifdef KTRACE
125 if (KTRPOINT(cnp->cn_proc, KTR_NAMEI))
126 ktrnamei(cnp->cn_proc->p_tracep, cnp->cn_pnbuf);
127 #endif
128
129 /*
130 * Get starting point for the translation.
131 */
132 ndp->ni_rootdir = fdp->fd_rdir;
133 ndp->ni_topdir = fdp->fd_jdir;
134
135 dp = fdp->fd_cdir;
136 VREF(dp);
137 for (;;) {
138 /*
139 * Check if root directory should replace current directory.
140 * Done at start of translation and after symbolic link.
141 */
142 cnp->cn_nameptr = cnp->cn_pnbuf;
143 if (*(cnp->cn_nameptr) == '/') {
144 vrele(dp);
145 while (*(cnp->cn_nameptr) == '/') {
146 cnp->cn_nameptr++;
147 ndp->ni_pathlen--;
148 }
149 dp = ndp->ni_rootdir;
150 VREF(dp);
151 }
152 ndp->ni_startdir = dp;
153 error = lookup(ndp);
154 if (error) {
155 zfree(namei_zone, cnp->cn_pnbuf);
156 return (error);
157 }
158 /*
159 * Check for symbolic link
160 */
161 if ((cnp->cn_flags & ISSYMLINK) == 0) {
162 if ((cnp->cn_flags & (SAVENAME | SAVESTART)) == 0)
163 zfree(namei_zone, cnp->cn_pnbuf);
164 else
165 cnp->cn_flags |= HASBUF;
166
167 if (vn_canvmio(ndp->ni_vp) == TRUE &&
168 (cnp->cn_nameiop != DELETE) &&
169 ((cnp->cn_flags & (NOOBJ|LOCKLEAF)) ==
170 LOCKLEAF))
171 vfs_object_create(ndp->ni_vp,
172 ndp->ni_cnd.cn_proc,
173 ndp->ni_cnd.cn_cred);
174
175 return (0);
176 }
177 if ((cnp->cn_flags & LOCKPARENT) && ndp->ni_pathlen == 1)
178 VOP_UNLOCK(ndp->ni_dvp, 0, p);
179 if (ndp->ni_loopcnt++ >= MAXSYMLINKS) {
180 error = ELOOP;
181 break;
182 }
183 if (ndp->ni_pathlen > 1)
184 cp = zalloc(namei_zone);
185 else
186 cp = cnp->cn_pnbuf;
187 aiov.iov_base = cp;
188 aiov.iov_len = MAXPATHLEN;
189 auio.uio_iov = &aiov;
190 auio.uio_iovcnt = 1;
191 auio.uio_offset = 0;
192 auio.uio_rw = UIO_READ;
193 auio.uio_segflg = UIO_SYSSPACE;
194 auio.uio_procp = (struct proc *)0;
195 auio.uio_resid = MAXPATHLEN;
196 error = VOP_READLINK(ndp->ni_vp, &auio, cnp->cn_cred);
197 if (error) {
198 if (ndp->ni_pathlen > 1)
199 zfree(namei_zone, cp);
200 break;
201 }
202 linklen = MAXPATHLEN - auio.uio_resid;
203 if (linklen == 0) {
204 if (ndp->ni_pathlen > 1)
205 zfree(namei_zone, cp);
206 error = ENOENT;
207 break;
208 }
209 if (linklen + ndp->ni_pathlen >= MAXPATHLEN) {
210 if (ndp->ni_pathlen > 1)
211 zfree(namei_zone, cp);
212 error = ENAMETOOLONG;
213 break;
214 }
215 if (ndp->ni_pathlen > 1) {
216 bcopy(ndp->ni_next, cp + linklen, ndp->ni_pathlen);
217 zfree(namei_zone, cnp->cn_pnbuf);
218 cnp->cn_pnbuf = cp;
219 } else
220 cnp->cn_pnbuf[linklen] = '\0';
221 ndp->ni_pathlen += linklen;
222 vput(ndp->ni_vp);
223 dp = ndp->ni_dvp;
224 }
225 zfree(namei_zone, cnp->cn_pnbuf);
226 vrele(ndp->ni_dvp);
227 vput(ndp->ni_vp);
228 ndp->ni_vp = NULL;
229 return (error);
230 }
231
232 /*
233 * Search a pathname.
234 * This is a very central and rather complicated routine.
235 *
236 * The pathname is pointed to by ni_ptr and is of length ni_pathlen.
237 * The starting directory is taken from ni_startdir. The pathname is
238 * descended until done, or a symbolic link is encountered. The variable
239 * ni_more is clear if the path is completed; it is set to one if a
240 * symbolic link needing interpretation is encountered.
241 *
242 * The flag argument is LOOKUP, CREATE, RENAME, or DELETE depending on
243 * whether the name is to be looked up, created, renamed, or deleted.
244 * When CREATE, RENAME, or DELETE is specified, information usable in
245 * creating, renaming, or deleting a directory entry may be calculated.
246 * If flag has LOCKPARENT or'ed into it, the parent directory is returned
247 * locked. If flag has WANTPARENT or'ed into it, the parent directory is
248 * returned unlocked. Otherwise the parent directory is not returned. If
249 * the target of the pathname exists and LOCKLEAF is or'ed into the flag
250 * the target is returned locked, otherwise it is returned unlocked.
251 * When creating or renaming and LOCKPARENT is specified, the target may not
252 * be ".". When deleting and LOCKPARENT is specified, the target may be ".".
253 *
254 * Overall outline of lookup:
255 *
256 * dirloop:
257 * identify next component of name at ndp->ni_ptr
258 * handle degenerate case where name is null string
259 * if .. and crossing mount points and on mounted filesys, find parent
260 * call VOP_LOOKUP routine for next component name
261 * directory vnode returned in ni_dvp, unlocked unless LOCKPARENT set
262 * component vnode returned in ni_vp (if it exists), locked.
263 * if result vnode is mounted on and crossing mount points,
264 * find mounted on vnode
265 * if more components of name, do next level at dirloop
266 * return the answer in ni_vp, locked if LOCKLEAF set
267 * if LOCKPARENT set, return locked parent in ni_dvp
268 * if WANTPARENT set, return unlocked parent in ni_dvp
269 */
270 int
271 lookup(ndp)
272 register struct nameidata *ndp;
273 {
274 register char *cp; /* pointer into pathname argument */
275 register struct vnode *dp = 0; /* the directory we are searching */
276 struct vnode *tdp; /* saved dp */
277 struct mount *mp; /* mount table entry */
278 int docache; /* == 0 do not cache last component */
279 int wantparent; /* 1 => wantparent or lockparent flag */
280 int rdonly; /* lookup read-only flag bit */
281 int trailing_slash;
282 int error = 0;
283 int dpunlocked = 0; /* dp has already been unlocked */
284 struct componentname *cnp = &ndp->ni_cnd;
285 struct proc *p = cnp->cn_proc;
286
287 /*
288 * Setup: break out flag bits into variables.
289 */
290 wantparent = cnp->cn_flags & (LOCKPARENT | WANTPARENT);
291 docache = (cnp->cn_flags & NOCACHE) ^ NOCACHE;
292 if (cnp->cn_nameiop == DELETE ||
293 (wantparent && cnp->cn_nameiop != CREATE &&
294 cnp->cn_nameiop != LOOKUP))
295 docache = 0;
296 rdonly = cnp->cn_flags & RDONLY;
297 ndp->ni_dvp = NULL;
298 cnp->cn_flags &= ~ISSYMLINK;
299 dp = ndp->ni_startdir;
300 ndp->ni_startdir = NULLVP;
301 vn_lock(dp, LK_EXCLUSIVE | LK_RETRY, p);
302
303 dirloop:
304 /*
305 * Search a new directory.
306 *
307 * The last component of the filename is left accessible via
308 * cnp->cn_nameptr for callers that need the name. Callers needing
309 * the name set the SAVENAME flag. When done, they assume
310 * responsibility for freeing the pathname buffer.
311 */
312 cnp->cn_consume = 0;
313 for (cp = cnp->cn_nameptr; *cp != 0 && *cp != '/'; cp++)
314 continue;
315 cnp->cn_namelen = cp - cnp->cn_nameptr;
316 if (cnp->cn_namelen > NAME_MAX) {
317 error = ENAMETOOLONG;
318 goto bad;
319 }
320 #ifdef NAMEI_DIAGNOSTIC
321 { char c = *cp;
322 *cp = '\0';
323 printf("{%s}: ", cnp->cn_nameptr);
324 *cp = c; }
325 #endif
326 ndp->ni_pathlen -= cnp->cn_namelen;
327 ndp->ni_next = cp;
328
329 /*
330 * Replace multiple slashes by a single slash and trailing slashes
331 * by a null. This must be done before VOP_LOOKUP() because some
332 * fs's don't know about trailing slashes. Remember if there were
333 * trailing slashes to handle symlinks, existing non-directories
334 * and non-existing files that won't be directories specially later.
335 */
336 trailing_slash = 0;
337 while (*cp == '/' && (cp[1] == '/' || cp[1] == '\0')) {
338 cp++;
339 ndp->ni_pathlen--;
340 if (*cp == '\0') {
341 trailing_slash = 1;
342 *ndp->ni_next = '\0'; /* XXX for direnter() ... */
343 }
344 }
345 ndp->ni_next = cp;
346
347 cnp->cn_flags |= MAKEENTRY;
348 if (*cp == '\0' && docache == 0)
349 cnp->cn_flags &= ~MAKEENTRY;
350 if (cnp->cn_namelen == 2 &&
351 cnp->cn_nameptr[1] == '.' && cnp->cn_nameptr[0] == '.')
352 cnp->cn_flags |= ISDOTDOT;
353 else
354 cnp->cn_flags &= ~ISDOTDOT;
355 if (*ndp->ni_next == 0)
356 cnp->cn_flags |= ISLASTCN;
357 else
358 cnp->cn_flags &= ~ISLASTCN;
359
360
361 /*
362 * Check for degenerate name (e.g. / or "")
363 * which is a way of talking about a directory,
364 * e.g. like "/." or ".".
365 */
366 if (cnp->cn_nameptr[0] == '\0') {
367 if (dp->v_type != VDIR) {
368 error = ENOTDIR;
369 goto bad;
370 }
371 if (cnp->cn_nameiop != LOOKUP) {
372 error = EISDIR;
373 goto bad;
374 }
375 if (wantparent) {
376 ndp->ni_dvp = dp;
377 VREF(dp);
378 }
379 ndp->ni_vp = dp;
380 if (!(cnp->cn_flags & (LOCKPARENT | LOCKLEAF)))
381 VOP_UNLOCK(dp, 0, p);
382 /* XXX This should probably move to the top of function. */
383 if (cnp->cn_flags & SAVESTART)
384 panic("lookup: SAVESTART");
385 return (0);
386 }
387
388 /*
389 * Handle "..": two special cases.
390 * 1. If at root directory (e.g. after chroot)
391 * or at absolute root directory
392 * then ignore it so can't get out.
393 * 2. If this vnode is the root of a mounted
394 * filesystem, then replace it with the
395 * vnode which was mounted on so we take the
396 * .. in the other file system.
397 * 3. If the vnode is the top directory of
398 * the jail or chroot, don't let them out.
399 */
400 if (cnp->cn_flags & ISDOTDOT) {
401 for (;;) {
402 if (dp == ndp->ni_rootdir ||
403 dp == ndp->ni_topdir ||
404 dp == rootvnode) {
405 ndp->ni_dvp = dp;
406 ndp->ni_vp = dp;
407 VREF(dp);
408 goto nextname;
409 }
410 if ((dp->v_flag & VROOT) == 0 ||
411 (cnp->cn_flags & NOCROSSMOUNT))
412 break;
413 if (dp->v_mount == NULL) { /* forced unmount */
414 error = EBADF;
415 goto bad;
416 }
417 tdp = dp;
418 dp = dp->v_mount->mnt_vnodecovered;
419 vput(tdp);
420 VREF(dp);
421 vn_lock(dp, LK_EXCLUSIVE | LK_RETRY, p);
422 }
423 }
424
425 /*
426 * We now have a segment name to search for, and a directory to search.
427 */
428 unionlookup:
429 ndp->ni_dvp = dp;
430 ndp->ni_vp = NULL;
431 cnp->cn_flags &= ~PDIRUNLOCK;
432 ASSERT_VOP_LOCKED(dp, "lookup");
433 if ((error = VOP_LOOKUP(dp, &ndp->ni_vp, cnp)) != 0) {
434 KASSERT(ndp->ni_vp == NULL, ("leaf should be empty"));
435 #ifdef NAMEI_DIAGNOSTIC
436 printf("not found\n");
437 #endif
438 if ((error == ENOENT) &&
439 (dp->v_flag & VROOT) && (dp->v_mount != NULL) &&
440 (dp->v_mount->mnt_flag & MNT_UNION)) {
441 tdp = dp;
442 dp = dp->v_mount->mnt_vnodecovered;
443 if (cnp->cn_flags & PDIRUNLOCK)
444 vrele(tdp);
445 else
446 vput(tdp);
447 VREF(dp);
448 vn_lock(dp, LK_EXCLUSIVE | LK_RETRY, p);
449 goto unionlookup;
450 }
451
452 if (error != EJUSTRETURN)
453 goto bad;
454 /*
455 * If creating and at end of pathname, then can consider
456 * allowing file to be created.
457 */
458 if (rdonly) {
459 error = EROFS;
460 goto bad;
461 }
462 if (*cp == '\0' && trailing_slash &&
463 !(cnp->cn_flags & WILLBEDIR)) {
464 error = ENOENT;
465 goto bad;
466 }
467 /*
468 * We return with ni_vp NULL to indicate that the entry
469 * doesn't currently exist, leaving a pointer to the
470 * (possibly locked) directory inode in ndp->ni_dvp.
471 */
472 if (cnp->cn_flags & SAVESTART) {
473 ndp->ni_startdir = ndp->ni_dvp;
474 VREF(ndp->ni_startdir);
475 }
476 return (0);
477 }
478 #ifdef NAMEI_DIAGNOSTIC
479 printf("found\n");
480 #endif
481
482 ASSERT_VOP_LOCKED(ndp->ni_vp, "lookup");
483
484 /*
485 * Take into account any additional components consumed by
486 * the underlying filesystem.
487 */
488 if (cnp->cn_consume > 0) {
489 cnp->cn_nameptr += cnp->cn_consume;
490 ndp->ni_next += cnp->cn_consume;
491 ndp->ni_pathlen -= cnp->cn_consume;
492 cnp->cn_consume = 0;
493 }
494
495 dp = ndp->ni_vp;
496
497 /*
498 * Check to see if the vnode has been mounted on;
499 * if so find the root of the mounted file system.
500 */
501 while (dp->v_type == VDIR && (mp = dp->v_mountedhere) &&
502 (cnp->cn_flags & NOCROSSMOUNT) == 0) {
503 if (vfs_busy(mp, 0, 0, p))
504 continue;
505 VOP_UNLOCK(dp, 0, p);
506 error = VFS_ROOT(mp, &tdp);
507 vfs_unbusy(mp, p);
508 if (error) {
509 dpunlocked = 1;
510 goto bad2;
511 }
512 vrele(dp);
513 ndp->ni_vp = dp = tdp;
514 }
515
516 /*
517 * Check for symbolic link
518 */
519 if ((dp->v_type == VLNK) &&
520 ((cnp->cn_flags & FOLLOW) || trailing_slash ||
521 *ndp->ni_next == '/')) {
522 cnp->cn_flags |= ISSYMLINK;
523 if (dp->v_mount == NULL) {
524 /* We can't know whether the directory was mounted with
525 * NOSYMFOLLOW, so we can't follow safely. */
526 error = EBADF;
527 goto bad2;
528 }
529 if (dp->v_mount->mnt_flag & MNT_NOSYMFOLLOW) {
530 error = EACCES;
531 goto bad2;
532 }
533 return (0);
534 }
535
536 /*
537 * Check for bogus trailing slashes.
538 */
539 if (trailing_slash && dp->v_type != VDIR) {
540 error = ENOTDIR;
541 goto bad2;
542 }
543
544 nextname:
545 /*
546 * Not a symbolic link. If more pathname,
547 * continue at next component, else return.
548 */
549 if (*ndp->ni_next == '/') {
550 cnp->cn_nameptr = ndp->ni_next;
551 while (*cnp->cn_nameptr == '/') {
552 cnp->cn_nameptr++;
553 ndp->ni_pathlen--;
554 }
555 if (ndp->ni_dvp != ndp->ni_vp)
556 ASSERT_VOP_UNLOCKED(ndp->ni_dvp, "lookup");
557 vrele(ndp->ni_dvp);
558 goto dirloop;
559 }
560 /*
561 * Disallow directory write attempts on read-only file systems.
562 */
563 if (rdonly &&
564 (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME)) {
565 error = EROFS;
566 goto bad2;
567 }
568 if (cnp->cn_flags & SAVESTART) {
569 ndp->ni_startdir = ndp->ni_dvp;
570 VREF(ndp->ni_startdir);
571 }
572 if (!wantparent)
573 vrele(ndp->ni_dvp);
574
575 if ((cnp->cn_flags & LOCKLEAF) == 0)
576 VOP_UNLOCK(dp, 0, p);
577 return (0);
578
579 bad2:
580 if ((cnp->cn_flags & (LOCKPARENT | PDIRUNLOCK)) == LOCKPARENT &&
581 *ndp->ni_next == '\0')
582 VOP_UNLOCK(ndp->ni_dvp, 0, p);
583 vrele(ndp->ni_dvp);
584 bad:
585 if (dpunlocked)
586 vrele(dp);
587 else
588 vput(dp);
589 ndp->ni_vp = NULL;
590 return (error);
591 }
592
593 /*
594 * relookup - lookup a path name component
595 * Used by lookup to re-aquire things.
596 */
597 int
598 relookup(dvp, vpp, cnp)
599 struct vnode *dvp, **vpp;
600 struct componentname *cnp;
601 {
602 struct proc *p = cnp->cn_proc;
603 struct vnode *dp = 0; /* the directory we are searching */
604 int docache; /* == 0 do not cache last component */
605 int wantparent; /* 1 => wantparent or lockparent flag */
606 int rdonly; /* lookup read-only flag bit */
607 int error = 0;
608 #ifdef NAMEI_DIAGNOSTIC
609 int newhash; /* DEBUG: check name hash */
610 char *cp; /* DEBUG: check name ptr/len */
611 #endif
612
613 /*
614 * Setup: break out flag bits into variables.
615 */
616 wantparent = cnp->cn_flags & (LOCKPARENT|WANTPARENT);
617 docache = (cnp->cn_flags & NOCACHE) ^ NOCACHE;
618 if (cnp->cn_nameiop == DELETE ||
619 (wantparent && cnp->cn_nameiop != CREATE))
620 docache = 0;
621 rdonly = cnp->cn_flags & RDONLY;
622 cnp->cn_flags &= ~ISSYMLINK;
623 dp = dvp;
624 vn_lock(dp, LK_EXCLUSIVE | LK_RETRY, p);
625
626 /* dirloop: */
627 /*
628 * Search a new directory.
629 *
630 * The last component of the filename is left accessible via
631 * cnp->cn_nameptr for callers that need the name. Callers needing
632 * the name set the SAVENAME flag. When done, they assume
633 * responsibility for freeing the pathname buffer.
634 */
635 #ifdef NAMEI_DIAGNOSTIC
636 if (cnp->cn_namelen != cp - cnp->cn_nameptr)
637 panic ("relookup: bad len");
638 if (*cp != 0)
639 panic("relookup: not last component");
640 printf("{%s}: ", cnp->cn_nameptr);
641 #endif
642
643 /*
644 * Check for degenerate name (e.g. / or "")
645 * which is a way of talking about a directory,
646 * e.g. like "/." or ".".
647 */
648 if (cnp->cn_nameptr[0] == '\0') {
649 if (cnp->cn_nameiop != LOOKUP || wantparent) {
650 error = EISDIR;
651 goto bad;
652 }
653 if (dp->v_type != VDIR) {
654 error = ENOTDIR;
655 goto bad;
656 }
657 if (!(cnp->cn_flags & LOCKLEAF))
658 VOP_UNLOCK(dp, 0, p);
659 *vpp = dp;
660 /* XXX This should probably move to the top of function. */
661 if (cnp->cn_flags & SAVESTART)
662 panic("lookup: SAVESTART");
663 return (0);
664 }
665
666 if (cnp->cn_flags & ISDOTDOT)
667 panic ("relookup: lookup on dot-dot");
668
669 /*
670 * We now have a segment name to search for, and a directory to search.
671 */
672 if ((error = VOP_LOOKUP(dp, vpp, cnp)) != 0) {
673 KASSERT(*vpp == NULL, ("leaf should be empty"));
674 if (error != EJUSTRETURN)
675 goto bad;
676 /*
677 * If creating and at end of pathname, then can consider
678 * allowing file to be created.
679 */
680 if (rdonly) {
681 error = EROFS;
682 goto bad;
683 }
684 /* ASSERT(dvp == ndp->ni_startdir) */
685 if (cnp->cn_flags & SAVESTART)
686 VREF(dvp);
687 /*
688 * We return with ni_vp NULL to indicate that the entry
689 * doesn't currently exist, leaving a pointer to the
690 * (possibly locked) directory inode in ndp->ni_dvp.
691 */
692 return (0);
693 }
694 dp = *vpp;
695
696 /*
697 * Check for symbolic link
698 */
699 KASSERT(dp->v_type != VLNK || !(cnp->cn_flags & FOLLOW),
700 ("relookup: symlink found.\n"));
701
702 /*
703 * Disallow directory write attempts on read-only file systems.
704 */
705 if (rdonly &&
706 (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME)) {
707 error = EROFS;
708 goto bad2;
709 }
710 /* ASSERT(dvp == ndp->ni_startdir) */
711 if (cnp->cn_flags & SAVESTART)
712 VREF(dvp);
713
714 if (!wantparent)
715 vrele(dvp);
716
717 if (vn_canvmio(dp) == TRUE &&
718 ((cnp->cn_flags & (NOOBJ|LOCKLEAF)) == LOCKLEAF))
719 vfs_object_create(dp, cnp->cn_proc, cnp->cn_cred);
720
721 if ((cnp->cn_flags & LOCKLEAF) == 0)
722 VOP_UNLOCK(dp, 0, p);
723 return (0);
724
725 bad2:
726 if ((cnp->cn_flags & LOCKPARENT) && (cnp->cn_flags & ISLASTCN))
727 VOP_UNLOCK(dvp, 0, p);
728 vrele(dvp);
729 bad:
730 vput(dp);
731 *vpp = NULL;
732 return (error);
733 }
Cache object: b48d4d5330dc1c84c6eb6d614e187d2d
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