1 /*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21
22 /*
23 * Copyright 2015 Nexenta Systems, Inc. All rights reserved.
24 * Copyright (c) 2015, Joyent, Inc. All rights reserved.
25 * Copyright (c) 1988, 2010, Oracle and/or its affiliates. All rights reserved.
26 */
27
28 /* Copyright (c) 1983, 1984, 1985, 1986, 1987, 1988, 1989 AT&T */
29 /* All Rights Reserved */
30
31 /*
32 * University Copyright- Copyright (c) 1982, 1986, 1988
33 * The Regents of the University of California
34 * All Rights Reserved
35 *
36 * University Acknowledgment- Portions of this document are derived from
37 * software developed by the University of California, Berkeley, and its
38 * contributors.
39 */
40
41 #include <sys/types.h>
42 #include <sys/param.h>
43 #include <sys/systm.h>
44 #include <sys/cpuvar.h>
45 #include <sys/errno.h>
46 #include <sys/cred.h>
47 #include <sys/user.h>
48 #include <sys/uio.h>
49 #include <sys/vfs.h>
50 #include <sys/vnode.h>
51 #include <sys/pathname.h>
52 #include <sys/proc.h>
53 #include <sys/vtrace.h>
54 #include <sys/sysmacros.h>
55 #include <sys/debug.h>
56 #include <sys/dirent.h>
57 #include <c2/audit.h>
58 #include <sys/zone.h>
59 #include <sys/dnlc.h>
60 #include <sys/fs/snode.h>
61 #include <sys/brand.h>
62
63 /* Controls whether paths are stored with vnodes. */
64 int vfs_vnode_path = 1;
65
66 int
67 lookupname(
68 char *fnamep,
69 enum uio_seg seg,
70 int followlink,
71 vnode_t **dirvpp,
72 vnode_t **compvpp)
73 {
74 return (lookupnameatcred(fnamep, seg, followlink, dirvpp, compvpp, NULL,
75 CRED()));
76 }
77
78 /*
79 * Lookup the user file name,
80 * Handle allocation and freeing of pathname buffer, return error.
81 */
82 int
83 lookupnameatcred(
84 char *fnamep, /* user pathname */
85 enum uio_seg seg, /* addr space that name is in */
86 int followlink, /* follow sym links */
87 vnode_t **dirvpp, /* ret for ptr to parent dir vnode */
88 vnode_t **compvpp, /* ret for ptr to component vnode */
89 vnode_t *startvp, /* start path search from vp */
90 cred_t *cr) /* credential */
91 {
92 char namebuf[TYPICALMAXPATHLEN];
93 struct pathname lookpn;
94 int error;
95
96 error = pn_get_buf(fnamep, seg, &lookpn, namebuf, sizeof (namebuf));
97 if (error == 0) {
98 error = lookuppnatcred(&lookpn, NULL, followlink,
99 dirvpp, compvpp, startvp, cr);
100 }
101 if (error == ENAMETOOLONG) {
102 /*
103 * This thread used a pathname > TYPICALMAXPATHLEN bytes long.
104 */
105 if (error = pn_get(fnamep, seg, &lookpn))
106 return (error);
107 error = lookuppnatcred(&lookpn, NULL, followlink,
108 dirvpp, compvpp, startvp, cr);
109 pn_free(&lookpn);
110 }
111
112 return (error);
113 }
114
115 int
116 lookupnameat(char *fnamep, enum uio_seg seg, int followlink,
117 vnode_t **dirvpp, vnode_t **compvpp, vnode_t *startvp)
118 {
119 return (lookupnameatcred(fnamep, seg, followlink, dirvpp, compvpp,
120 startvp, CRED()));
121 }
122
123 int
124 lookuppn(
125 struct pathname *pnp,
126 struct pathname *rpnp,
127 int followlink,
128 vnode_t **dirvpp,
129 vnode_t **compvpp)
130 {
131 return (lookuppnatcred(pnp, rpnp, followlink, dirvpp, compvpp, NULL,
132 CRED()));
133 }
134
135 /*
136 * Lookup the user file name from a given vp, using a specific credential.
137 */
138 int
139 lookuppnatcred(
140 struct pathname *pnp, /* pathname to lookup */
141 struct pathname *rpnp, /* if non-NULL, return resolved path */
142 int followlink, /* (don't) follow sym links */
143 vnode_t **dirvpp, /* ptr for parent vnode */
144 vnode_t **compvpp, /* ptr for entry vnode */
145 vnode_t *startvp, /* start search from this vp */
146 cred_t *cr) /* user credential */
147 {
148 vnode_t *vp; /* current directory vp */
149 vnode_t *rootvp;
150 proc_t *p = curproc;
151
152 if (pnp->pn_pathlen == 0)
153 return (ENOENT);
154
155 mutex_enter(&p->p_lock); /* for u_rdir and u_cdir */
156 if ((rootvp = PTOU(p)->u_rdir) == NULL)
157 rootvp = rootdir;
158 else if (rootvp != rootdir) /* no need to VN_HOLD rootdir */
159 VN_HOLD(rootvp);
160
161 if (pnp->pn_path[0] == '/') {
162 vp = rootvp;
163 } else {
164 vp = (startvp == NULL) ? PTOU(p)->u_cdir : startvp;
165 }
166 VN_HOLD(vp);
167 mutex_exit(&p->p_lock);
168
169 /*
170 * Skip over leading slashes
171 */
172 if (pnp->pn_path[0] == '/') {
173 do {
174 pnp->pn_path++;
175 pnp->pn_pathlen--;
176 } while (pnp->pn_path[0] == '/');
177 }
178
179 return (lookuppnvp(pnp, rpnp, followlink, dirvpp,
180 compvpp, rootvp, vp, cr));
181 }
182
183 int
184 lookuppnat(struct pathname *pnp, struct pathname *rpnp,
185 int followlink, vnode_t **dirvpp, vnode_t **compvpp,
186 vnode_t *startvp)
187 {
188 return (lookuppnatcred(pnp, rpnp, followlink, dirvpp, compvpp, startvp,
189 CRED()));
190 }
191
192 /* Private flag to do our getcwd() dirty work */
193 #define LOOKUP_CHECKREAD 0x10
194 #define LOOKUP_MASK (~LOOKUP_CHECKREAD)
195
196 /*
197 * Starting at current directory, translate pathname pnp to end.
198 * Leave pathname of final component in pnp, return the vnode
199 * for the final component in *compvpp, and return the vnode
200 * for the parent of the final component in dirvpp.
201 *
202 * This is the central routine in pathname translation and handles
203 * multiple components in pathnames, separating them at /'s. It also
204 * implements mounted file systems and processes symbolic links.
205 *
206 * vp is the vnode where the directory search should start.
207 *
208 * Reference counts: vp must be held prior to calling this function. rootvp
209 * should only be held if rootvp != rootdir.
210 */
211 int
212 lookuppnvp(
213 struct pathname *pnp, /* pathname to lookup */
214 struct pathname *rpnp, /* if non-NULL, return resolved path */
215 int flags, /* follow symlinks */
216 vnode_t **dirvpp, /* ptr for parent vnode */
217 vnode_t **compvpp, /* ptr for entry vnode */
218 vnode_t *rootvp, /* rootvp */
219 vnode_t *vp, /* directory to start search at */
220 cred_t *cr) /* user's credential */
221 {
222 vnode_t *cvp; /* current component vp */
223 char component[MAXNAMELEN]; /* buffer for component (incl null) */
224 int error;
225 int nlink;
226 int lookup_flags;
227 struct pathname presrvd; /* case preserved name */
228 struct pathname *pp = NULL;
229 vnode_t *startvp;
230 vnode_t *zonevp = curproc->p_zone->zone_rootvp; /* zone root */
231 int must_be_directory = 0;
232 boolean_t retry_with_kcred;
233 uint32_t auditing = AU_AUDITING();
234
235 CPU_STATS_ADDQ(CPU, sys, namei, 1);
236 nlink = 0;
237 cvp = NULL;
238 if (rpnp)
239 rpnp->pn_pathlen = 0;
240
241 lookup_flags = dirvpp ? LOOKUP_DIR : 0;
242 if (flags & FIGNORECASE) {
243 lookup_flags |= FIGNORECASE;
244 pn_alloc(&presrvd);
245 pp = &presrvd;
246 }
247
248 if (auditing)
249 audit_anchorpath(pnp, vp == rootvp);
250
251 /*
252 * Eliminate any trailing slashes in the pathname.
253 * If there are any, we must follow all symlinks.
254 * Also, we must guarantee that the last component is a directory.
255 */
256 if (pn_fixslash(pnp)) {
257 flags |= FOLLOW;
258 must_be_directory = 1;
259 }
260
261 startvp = vp;
262 next:
263 retry_with_kcred = B_FALSE;
264
265 /*
266 * Make sure we have a directory.
267 */
268 if (vp->v_type != VDIR) {
269 error = ENOTDIR;
270 goto bad;
271 }
272
273 if (rpnp && VN_CMP(vp, rootvp))
274 (void) pn_set(rpnp, "/");
275
276 /*
277 * Process the next component of the pathname.
278 */
279 if (error = pn_getcomponent(pnp, component)) {
280 goto bad;
281 }
282
283 /*
284 * Handle "..": two special cases.
285 * 1. If we're at the root directory (e.g. after chroot or
286 * zone_enter) then change ".." to "." so we can't get
287 * out of this subtree.
288 * 2. If this vnode is the root of a mounted file system,
289 * then replace it with the vnode that was mounted on
290 * so that we take the ".." in the other file system.
291 */
292 if (component[0] == '.' && component[1] == '.' && component[2] == 0) {
293 checkforroot:
294 if (VN_CMP(vp, rootvp) || VN_CMP(vp, zonevp)) {
295 component[1] = '\0';
296 } else if (vp->v_flag & VROOT) {
297 vfs_t *vfsp;
298 cvp = vp;
299
300 /*
301 * While we deal with the vfs pointer from the vnode
302 * the filesystem could have been forcefully unmounted
303 * and the vnode's v_vfsp could have been invalidated
304 * by VFS_UNMOUNT. Hence, we cache v_vfsp and use it
305 * with vfs_rlock_wait/vfs_unlock.
306 * It is safe to use the v_vfsp even it is freed by
307 * VFS_UNMOUNT because vfs_rlock_wait/vfs_unlock
308 * do not dereference v_vfsp. It is just used as a
309 * magic cookie.
310 * One more corner case here is the memory getting
311 * reused for another vfs structure. In this case
312 * lookuppnvp's vfs_rlock_wait will succeed, domount's
313 * vfs_lock will fail and domount will bail out with an
314 * error (EBUSY).
315 */
316 vfsp = cvp->v_vfsp;
317
318 /*
319 * This lock is used to synchronize
320 * mounts/unmounts and lookups.
321 * Threads doing mounts/unmounts hold the
322 * writers version vfs_lock_wait().
323 */
324
325 vfs_rlock_wait(vfsp);
326
327 /*
328 * If this vnode is on a file system that
329 * has been forcibly unmounted,
330 * we can't proceed. Cancel this operation
331 * and return EIO.
332 *
333 * vfs_vnodecovered is NULL if unmounted.
334 * Currently, nfs uses VFS_UNMOUNTED to
335 * check if it's a forced-umount. Keep the
336 * same checking here as well even though it
337 * may not be needed.
338 */
339 if (((vp = cvp->v_vfsp->vfs_vnodecovered) == NULL) ||
340 (cvp->v_vfsp->vfs_flag & VFS_UNMOUNTED)) {
341 vfs_unlock(vfsp);
342 VN_RELE(cvp);
343 if (pp)
344 pn_free(pp);
345 return (EIO);
346 }
347 VN_HOLD(vp);
348 vfs_unlock(vfsp);
349 VN_RELE(cvp);
350 cvp = NULL;
351 /*
352 * Crossing mount points. For eg: We are doing
353 * a lookup of ".." for file systems root vnode
354 * mounted here, and VOP_LOOKUP() (with covered vnode)
355 * will be on underlying file systems mount point
356 * vnode. Set retry_with_kcred flag as we might end
357 * up doing VOP_LOOKUP() with kcred if required.
358 */
359 retry_with_kcred = B_TRUE;
360 goto checkforroot;
361 }
362 }
363
364 /*
365 * LOOKUP_CHECKREAD is a private flag used by vnodetopath() to indicate
366 * that we need to have read permission on every directory in the entire
367 * path. This is used to ensure that a forward-lookup of a cached value
368 * has the same effect as a reverse-lookup when the cached value cannot
369 * be found.
370 */
371 if ((flags & LOOKUP_CHECKREAD) &&
372 (error = VOP_ACCESS(vp, VREAD, 0, cr, NULL)) != 0)
373 goto bad;
374
375 /*
376 * Perform a lookup in the current directory.
377 */
378 error = VOP_LOOKUP(vp, component, &cvp, pnp, lookup_flags,
379 rootvp, cr, NULL, NULL, pp);
380
381 /*
382 * Retry with kcred - If crossing mount points & error is EACCES.
383 *
384 * If we are crossing mount points here and doing ".." lookup,
385 * VOP_LOOKUP() might fail if the underlying file systems
386 * mount point has no execute permission. In cases like these,
387 * we retry VOP_LOOKUP() by giving as much privilage as possible
388 * by passing kcred credentials.
389 *
390 * In case of hierarchical file systems, passing kcred still may
391 * or may not work.
392 * For eg: UFS FS --> Mount NFS FS --> Again mount UFS on some
393 * directory inside NFS FS.
394 */
395 if ((error == EACCES) && retry_with_kcred)
396 error = VOP_LOOKUP(vp, component, &cvp, pnp, lookup_flags,
397 rootvp, zone_kcred(), NULL, NULL, pp);
398
399 if (error) {
400 cvp = NULL;
401 /*
402 * On error, return hard error if
403 * (a) we're not at the end of the pathname yet, or
404 * (b) the caller didn't want the parent directory, or
405 * (c) we failed for some reason other than a missing entry.
406 */
407 if (pn_pathleft(pnp) || dirvpp == NULL || error != ENOENT)
408 goto bad;
409 if (auditing) { /* directory access */
410 if (error = audit_savepath(pnp, vp, vp, error, cr))
411 goto bad_noaudit;
412 }
413
414 pn_setlast(pnp);
415 /*
416 * We inform the caller that the desired entry must be
417 * a directory by adding a '/' to the component name.
418 */
419 if (must_be_directory && (error = pn_addslash(pnp)) != 0)
420 goto bad;
421 *dirvpp = vp;
422 if (compvpp != NULL)
423 *compvpp = NULL;
424 if (rootvp != rootdir)
425 VN_RELE(rootvp);
426 if (pp)
427 pn_free(pp);
428 return (0);
429 }
430
431 /*
432 * Traverse mount points.
433 * XXX why don't we need to hold a read lock here (call vn_vfsrlock)?
434 * What prevents a concurrent update to v_vfsmountedhere?
435 * Possible answer: if mounting, we might not see the mount
436 * if it is concurrently coming into existence, but that's
437 * really not much different from the thread running a bit slower.
438 * If unmounting, we may get into traverse() when we shouldn't,
439 * but traverse() will catch this case for us.
440 * (For this to work, fetching v_vfsmountedhere had better
441 * be atomic!)
442 */
443 if (vn_mountedvfs(cvp) != NULL) {
444 if ((error = traverse(&cvp)) != 0)
445 goto bad;
446 }
447
448 /*
449 * If we hit a symbolic link and there is more path to be
450 * translated or this operation does not wish to apply
451 * to a link, then place the contents of the link at the
452 * front of the remaining pathname.
453 */
454 if (cvp->v_type == VLNK && ((flags & FOLLOW) || pn_pathleft(pnp))) {
455 struct pathname linkpath;
456
457 if (++nlink > MAXSYMLINKS) {
458 error = ELOOP;
459 goto bad;
460 }
461 pn_alloc(&linkpath);
462 if (error = pn_getsymlink(cvp, &linkpath, cr)) {
463 pn_free(&linkpath);
464 goto bad;
465 }
466
467 if (auditing)
468 audit_symlink(pnp, &linkpath);
469
470 if (pn_pathleft(&linkpath) == 0)
471 (void) pn_set(&linkpath, ".");
472 error = pn_insert(pnp, &linkpath, strlen(component));
473 pn_free(&linkpath);
474 if (error)
475 goto bad;
476 VN_RELE(cvp);
477 cvp = NULL;
478 if (pnp->pn_pathlen == 0) {
479 error = ENOENT;
480 goto bad;
481 }
482 if (pnp->pn_path[0] == '/') {
483 do {
484 pnp->pn_path++;
485 pnp->pn_pathlen--;
486 } while (pnp->pn_path[0] == '/');
487 VN_RELE(vp);
488 vp = rootvp;
489 VN_HOLD(vp);
490 }
491 if (auditing)
492 audit_anchorpath(pnp, vp == rootvp);
493 if (pn_fixslash(pnp)) {
494 flags |= FOLLOW;
495 must_be_directory = 1;
496 }
497 goto next;
498 }
499
500 /*
501 * If rpnp is non-NULL, remember the resolved path name therein.
502 * Do not include "." components. Collapse occurrences of
503 * "previous/..", so long as "previous" is not itself "..".
504 * Exhausting rpnp results in error ENAMETOOLONG.
505 */
506 if (rpnp && strcmp(component, ".") != 0) {
507 size_t len;
508
509 if (strcmp(component, "..") == 0 &&
510 rpnp->pn_pathlen != 0 &&
511 !((rpnp->pn_pathlen > 2 &&
512 strncmp(rpnp->pn_path+rpnp->pn_pathlen-3, "/..", 3) == 0) ||
513 (rpnp->pn_pathlen == 2 &&
514 strncmp(rpnp->pn_path, "..", 2) == 0))) {
515 while (rpnp->pn_pathlen &&
516 rpnp->pn_path[rpnp->pn_pathlen-1] != '/')
517 rpnp->pn_pathlen--;
518 if (rpnp->pn_pathlen > 1)
519 rpnp->pn_pathlen--;
520 rpnp->pn_path[rpnp->pn_pathlen] = '\0';
521 } else {
522 if (rpnp->pn_pathlen != 0 &&
523 rpnp->pn_path[rpnp->pn_pathlen-1] != '/')
524 rpnp->pn_path[rpnp->pn_pathlen++] = '/';
525 if (flags & FIGNORECASE) {
526 /*
527 * Return the case-preserved name
528 * within the resolved path.
529 */
530 error = copystr(pp->pn_buf,
531 rpnp->pn_path + rpnp->pn_pathlen,
532 rpnp->pn_bufsize - rpnp->pn_pathlen, &len);
533 } else {
534 error = copystr(component,
535 rpnp->pn_path + rpnp->pn_pathlen,
536 rpnp->pn_bufsize - rpnp->pn_pathlen, &len);
537 }
538 if (error) /* copystr() returns ENAMETOOLONG */
539 goto bad;
540 rpnp->pn_pathlen += (len - 1);
541 ASSERT(rpnp->pn_bufsize > rpnp->pn_pathlen);
542 }
543 }
544
545 /*
546 * If no more components, return last directory (if wanted) and
547 * last component (if wanted).
548 */
549 if (pn_pathleft(pnp) == 0) {
550 /*
551 * If there was a trailing slash in the pathname,
552 * make sure the last component is a directory.
553 */
554 if (must_be_directory && cvp->v_type != VDIR) {
555 error = ENOTDIR;
556 goto bad;
557 }
558 if (dirvpp != NULL) {
559 /*
560 * Check that we have the real parent and not
561 * an alias of the last component.
562 */
563 if (vn_compare(vp, cvp)) {
564 if (auditing)
565 (void) audit_savepath(pnp, cvp, vp,
566 EINVAL, cr);
567 pn_setlast(pnp);
568 VN_RELE(vp);
569 VN_RELE(cvp);
570 if (rootvp != rootdir)
571 VN_RELE(rootvp);
572 if (pp)
573 pn_free(pp);
574 return (EINVAL);
575 }
576 *dirvpp = vp;
577 } else
578 VN_RELE(vp);
579 if (auditing)
580 (void) audit_savepath(pnp, cvp, vp, 0, cr);
581 if (pnp->pn_path == pnp->pn_buf)
582 (void) pn_set(pnp, ".");
583 else
584 pn_setlast(pnp);
585 if (rpnp) {
586 if (VN_CMP(cvp, rootvp))
587 (void) pn_set(rpnp, "/");
588 else if (rpnp->pn_pathlen == 0)
589 (void) pn_set(rpnp, ".");
590 }
591
592 if (compvpp != NULL)
593 *compvpp = cvp;
594 else
595 VN_RELE(cvp);
596 if (rootvp != rootdir)
597 VN_RELE(rootvp);
598 if (pp)
599 pn_free(pp);
600 return (0);
601 }
602
603 /*
604 * Skip over slashes from end of last component.
605 */
606 while (pnp->pn_path[0] == '/') {
607 pnp->pn_path++;
608 pnp->pn_pathlen--;
609 }
610
611 /*
612 * Searched through another level of directory:
613 * release previous directory handle and save new (result
614 * of lookup) as current directory.
615 */
616 VN_RELE(vp);
617 vp = cvp;
618 cvp = NULL;
619 goto next;
620
621 bad:
622 if (auditing) /* reached end of path */
623 (void) audit_savepath(pnp, cvp, vp, error, cr);
624 bad_noaudit:
625 /*
626 * Error. Release vnodes and return.
627 */
628 if (cvp)
629 VN_RELE(cvp);
630 /*
631 * If the error was ESTALE and the current directory to look in
632 * was the root for this lookup, the root for a mounted file
633 * system, or the starting directory for lookups, then
634 * return ENOENT instead of ESTALE. In this case, no recovery
635 * is possible by the higher level. If ESTALE was returned for
636 * some intermediate directory along the path, then recovery
637 * is potentially possible and retrying from the higher level
638 * will either correct the situation by purging stale cache
639 * entries or eventually get back to the point where no recovery
640 * is possible.
641 */
642 if (error == ESTALE &&
643 (VN_CMP(vp, rootvp) || (vp->v_flag & VROOT) || vp == startvp))
644 error = ENOENT;
645 VN_RELE(vp);
646 if (rootvp != rootdir)
647 VN_RELE(rootvp);
648 if (pp)
649 pn_free(pp);
650 return (error);
651 }
652
653 /*
654 * Traverse a mount point. Routine accepts a vnode pointer as a reference
655 * parameter and performs the indirection, releasing the original vnode.
656 */
657 int
658 traverse(vnode_t **cvpp)
659 {
660 int error = 0;
661 vnode_t *cvp;
662 vnode_t *tvp;
663 vfs_t *vfsp;
664
665 cvp = *cvpp;
666
667 /*
668 * If this vnode is mounted on, then we transparently indirect
669 * to the vnode which is the root of the mounted file system.
670 * Before we do this we must check that an unmount is not in
671 * progress on this vnode.
672 */
673
674 for (;;) {
675 /*
676 * Try to read lock the vnode. If this fails because
677 * the vnode is already write locked, then check to
678 * see whether it is the current thread which locked
679 * the vnode. If it is not, then read lock the vnode
680 * by waiting to acquire the lock.
681 *
682 * The code path in domount() is an example of support
683 * which needs to look up two pathnames and locks one
684 * of them in between the two lookups.
685 */
686 error = vn_vfsrlock(cvp);
687 if (error) {
688 if (!vn_vfswlock_held(cvp))
689 error = vn_vfsrlock_wait(cvp);
690 if (error != 0) {
691 /*
692 * lookuppn() expects a held vnode to be
693 * returned because it promptly calls
694 * VN_RELE after the error return
695 */
696 *cvpp = cvp;
697 return (error);
698 }
699 }
700
701 /*
702 * Reached the end of the mount chain?
703 */
704 vfsp = vn_mountedvfs(cvp);
705 if (vfsp == NULL) {
706 vn_vfsunlock(cvp);
707 break;
708 }
709
710 /*
711 * The read lock must be held across the call to VFS_ROOT() to
712 * prevent a concurrent unmount from destroying the vfs.
713 */
714 error = VFS_ROOT(vfsp, &tvp);
715 vn_vfsunlock(cvp);
716
717 if (error)
718 break;
719
720 VN_RELE(cvp);
721
722 cvp = tvp;
723 }
724
725 *cvpp = cvp;
726 return (error);
727 }
728
729 /*
730 * Return the lowermost vnode if this is a mountpoint.
731 */
732 static vnode_t *
733 vn_under(vnode_t *vp)
734 {
735 vnode_t *uvp;
736 vfs_t *vfsp;
737
738 while (vp->v_flag & VROOT) {
739
740 vfsp = vp->v_vfsp;
741 vfs_rlock_wait(vfsp);
742 if ((uvp = vfsp->vfs_vnodecovered) == NULL ||
743 (vfsp->vfs_flag & VFS_UNMOUNTED)) {
744 vfs_unlock(vfsp);
745 break;
746 }
747 VN_HOLD(uvp);
748 vfs_unlock(vfsp);
749 VN_RELE(vp);
750 vp = uvp;
751 }
752
753 return (vp);
754 }
755
756 static int
757 vnode_match(vnode_t *v1, vnode_t *v2, cred_t *cr)
758 {
759 vattr_t v1attr, v2attr;
760
761 /*
762 * If we have a device file, check to see if is a cloned open of the
763 * same device. For self-cloning devices, the major numbers will match.
764 * For devices cloned through the 'clone' driver, the minor number of
765 * the source device will be the same as the major number of the cloned
766 * device.
767 */
768 if ((v1->v_type == VCHR || v1->v_type == VBLK) &&
769 v1->v_type == v2->v_type) {
770 if ((spec_is_selfclone(v1) || spec_is_selfclone(v2)) &&
771 getmajor(v1->v_rdev) == getmajor(v2->v_rdev))
772 return (1);
773
774 if (spec_is_clone(v1) &&
775 getmajor(v1->v_rdev) == getminor(v2->v_rdev))
776 return (1);
777
778 if (spec_is_clone(v2) &&
779 getmajor(v2->v_rdev) == getminor(v1->v_rdev))
780 return (1);
781 }
782
783 v1attr.va_mask = v2attr.va_mask = AT_TYPE;
784
785 /*
786 * This check for symbolic links handles the pseudo-symlinks in procfs.
787 * These particular links have v_type of VDIR, but the attributes have a
788 * type of VLNK. We need to avoid these links because otherwise if we
789 * are currently in '/proc/self/fd', then '/proc/self/cwd' will compare
790 * as the same vnode.
791 */
792 if (VOP_GETATTR(v1, &v1attr, 0, cr, NULL) != 0 ||
793 VOP_GETATTR(v2, &v2attr, 0, cr, NULL) != 0 ||
794 v1attr.va_type == VLNK || v2attr.va_type == VLNK)
795 return (0);
796
797 v1attr.va_mask = v2attr.va_mask = AT_TYPE | AT_FSID | AT_NODEID;
798
799 if (VOP_GETATTR(v1, &v1attr, ATTR_REAL, cr, NULL) != 0 ||
800 VOP_GETATTR(v2, &v2attr, ATTR_REAL, cr, NULL) != 0)
801 return (0);
802
803 return (v1attr.va_fsid == v2attr.va_fsid &&
804 v1attr.va_nodeid == v2attr.va_nodeid);
805 }
806
807
808 /*
809 * Find the entry in the directory corresponding to the target vnode.
810 */
811 int
812 dirfindvp(vnode_t *vrootp, vnode_t *dvp, vnode_t *tvp, cred_t *cr, char *dbuf,
813 size_t dlen, dirent64_t **rdp)
814 {
815 size_t dbuflen;
816 struct iovec iov;
817 struct uio uio;
818 int error;
819 int eof;
820 vnode_t *cmpvp;
821 struct dirent64 *dp;
822 pathname_t pnp;
823
824 ASSERT(dvp->v_type == VDIR);
825
826 /*
827 * This is necessary because of the strange semantics of VOP_LOOKUP().
828 */
829 bzero(&pnp, sizeof (pnp));
830
831 eof = 0;
832
833 uio.uio_iov = &iov;
834 uio.uio_iovcnt = 1;
835 uio.uio_segflg = UIO_SYSSPACE;
836 uio.uio_fmode = 0;
837 uio.uio_extflg = UIO_COPY_CACHED;
838 uio.uio_loffset = 0;
839
840 if ((error = VOP_ACCESS(dvp, VREAD, 0, cr, NULL)) != 0)
841 return (error);
842
843 while (!eof) {
844 uio.uio_resid = dlen;
845 iov.iov_base = dbuf;
846 iov.iov_len = dlen;
847
848 (void) VOP_RWLOCK(dvp, V_WRITELOCK_FALSE, NULL);
849 error = VOP_READDIR(dvp, &uio, cr, &eof, NULL, 0);
850 VOP_RWUNLOCK(dvp, V_WRITELOCK_FALSE, NULL);
851
852 dbuflen = dlen - uio.uio_resid;
853
854 if (error || dbuflen == 0)
855 break;
856
857 dp = (dirent64_t *)dbuf;
858 while ((intptr_t)dp < (intptr_t)dbuf + dbuflen) {
859 /*
860 * Ignore '.' and '..' entries
861 */
862 if (strcmp(dp->d_name, ".") == 0 ||
863 strcmp(dp->d_name, "..") == 0) {
864 dp = (dirent64_t *)((intptr_t)dp +
865 dp->d_reclen);
866 continue;
867 }
868
869 error = VOP_LOOKUP(dvp, dp->d_name, &cmpvp, &pnp, 0,
870 vrootp, cr, NULL, NULL, NULL);
871
872 /*
873 * We only want to bail out if there was an error other
874 * than ENOENT. Otherwise, it could be that someone
875 * just removed an entry since the readdir() call, and
876 * the entry we want is further on in the directory.
877 */
878 if (error == 0) {
879 if (vnode_match(tvp, cmpvp, cr)) {
880 VN_RELE(cmpvp);
881 *rdp = dp;
882 return (0);
883 }
884
885 VN_RELE(cmpvp);
886 } else if (error != ENOENT) {
887 return (error);
888 }
889
890 dp = (dirent64_t *)((intptr_t)dp + dp->d_reclen);
891 }
892 }
893
894 /*
895 * Something strange has happened, this directory does not contain the
896 * specified vnode. This should never happen in the normal case, since
897 * we ensured that dvp is the parent of vp. This is possible in some
898 * rare conditions (races and the special .zfs directory).
899 */
900 if (error == 0) {
901 error = VOP_LOOKUP(dvp, ".zfs", &cmpvp, &pnp, 0, vrootp, cr,
902 NULL, NULL, NULL);
903 if (error == 0) {
904 if (vnode_match(tvp, cmpvp, cr)) {
905 (void) strcpy(dp->d_name, ".zfs");
906 dp->d_reclen = strlen(".zfs");
907 dp->d_off = 2;
908 dp->d_ino = 1;
909 *rdp = dp;
910 } else {
911 error = ENOENT;
912 }
913 VN_RELE(cmpvp);
914 }
915 }
916
917 return (error);
918 }
919
920 /*
921 * Given a global path (from rootdir), and a vnode that is the current root,
922 * return the portion of the path that is beneath the current root or NULL on
923 * failure. The path MUST be a resolved path (no '..' entries or symlinks),
924 * otherwise this function will fail.
925 */
926 static char *
927 localpath(char *path, struct vnode *vrootp, cred_t *cr)
928 {
929 vnode_t *vp;
930 vnode_t *cvp;
931 char component[MAXNAMELEN];
932 char *ret = NULL;
933 pathname_t pn;
934
935 /*
936 * We use vn_compare() instead of VN_CMP() in order to detect lofs
937 * mounts and stacked vnodes.
938 */
939 if (vn_compare(vrootp, rootdir))
940 return (path);
941
942 if (pn_get(path, UIO_SYSSPACE, &pn) != 0)
943 return (NULL);
944
945 vp = rootdir;
946 VN_HOLD(vp);
947
948 if (vn_ismntpt(vp) && traverse(&vp) != 0) {
949 VN_RELE(vp);
950 pn_free(&pn);
951 return (NULL);
952 }
953
954 while (pn_pathleft(&pn)) {
955 pn_skipslash(&pn);
956
957 if (pn_getcomponent(&pn, component) != 0)
958 break;
959
960 if (VOP_LOOKUP(vp, component, &cvp, &pn, 0, rootdir, cr,
961 NULL, NULL, NULL) != 0)
962 break;
963 VN_RELE(vp);
964 vp = cvp;
965
966 if (vn_ismntpt(vp) && traverse(&vp) != 0)
967 break;
968
969 if (vn_compare(vp, vrootp)) {
970 ret = path + (pn.pn_path - pn.pn_buf);
971 break;
972 }
973 }
974
975 VN_RELE(vp);
976 pn_free(&pn);
977
978 return (ret);
979 }
980
981 /*
982 * Given a directory, return the full, resolved path. This looks up "..",
983 * searches for the given vnode in the parent, appends the component, etc. It
984 * is used to implement vnodetopath() and getcwd() when the cached path fails.
985 */
986 static int
987 dirtopath(vnode_t *vrootp, vnode_t *vp, char *buf, size_t buflen, int flags,
988 cred_t *cr)
989 {
990 pathname_t pn, rpn, emptypn;
991 vnode_t *cmpvp, *pvp = NULL;
992 vnode_t *startvp = vp;
993 int err = 0, vprivs;
994 size_t complen;
995 char *dbuf;
996 dirent64_t *dp;
997 char *bufloc;
998 size_t dlen = DIRENT64_RECLEN(MAXPATHLEN);
999 refstr_t *mntpt;
1000
1001 /* Operation only allowed on directories */
1002 ASSERT(vp->v_type == VDIR);
1003
1004 /* We must have at least enough space for "/" */
1005 if (buflen < 2)
1006 return (ENAMETOOLONG);
1007
1008 /* Start at end of string with terminating null */
1009 bufloc = &buf[buflen - 1];
1010 *bufloc = '\0';
1011
1012 pn_alloc(&pn);
1013 pn_alloc(&rpn);
1014 dbuf = kmem_alloc(dlen, KM_SLEEP);
1015 bzero(&emptypn, sizeof (emptypn));
1016
1017 /*
1018 * Begin with an additional reference on vp. This will be decremented
1019 * during the loop.
1020 */
1021 VN_HOLD(vp);
1022
1023 for (;;) {
1024 /*
1025 * Return if we've reached the root. If the buffer is empty,
1026 * return '/'. We explicitly don't use vn_compare(), since it
1027 * compares the real vnodes. A lofs mount of '/' would produce
1028 * incorrect results otherwise.
1029 */
1030 if (VN_CMP(vrootp, vp)) {
1031 if (*bufloc == '\0')
1032 *--bufloc = '/';
1033 break;
1034 }
1035
1036 /*
1037 * If we've reached the VFS root, something has gone wrong. We
1038 * should have reached the root in the above check. The only
1039 * explantation is that 'vp' is not contained withing the given
1040 * root, in which case we return EPERM.
1041 */
1042 if (VN_CMP(rootdir, vp)) {
1043 err = EPERM;
1044 goto out;
1045 }
1046
1047 /*
1048 * Shortcut: see if this vnode is a mountpoint. If so,
1049 * grab the path information from the vfs_t.
1050 */
1051 if (vp->v_flag & VROOT) {
1052
1053 mntpt = vfs_getmntpoint(vp->v_vfsp);
1054 if ((err = pn_set(&pn, (char *)refstr_value(mntpt)))
1055 == 0) {
1056 refstr_rele(mntpt);
1057 rpn.pn_path = rpn.pn_buf;
1058
1059 /*
1060 * Ensure the mountpoint still exists.
1061 */
1062 VN_HOLD(vrootp);
1063 if (vrootp != rootdir)
1064 VN_HOLD(vrootp);
1065 if (lookuppnvp(&pn, &rpn, flags, NULL,
1066 &cmpvp, vrootp, vrootp, cr) == 0) {
1067
1068 if (VN_CMP(vp, cmpvp)) {
1069 VN_RELE(cmpvp);
1070
1071 complen = strlen(rpn.pn_path);
1072 bufloc -= complen;
1073 if (bufloc < buf) {
1074 err = ERANGE;
1075 goto out;
1076 }
1077 bcopy(rpn.pn_path, bufloc,
1078 complen);
1079 break;
1080 } else {
1081 VN_RELE(cmpvp);
1082 }
1083 }
1084 } else {
1085 refstr_rele(mntpt);
1086 }
1087 }
1088
1089 /*
1090 * Shortcut: see if this vnode has correct v_path. If so,
1091 * we have the work done.
1092 */
1093 mutex_enter(&vp->v_lock);
1094 if (vp->v_path != NULL) {
1095
1096 if ((err = pn_set(&pn, vp->v_path)) == 0) {
1097 mutex_exit(&vp->v_lock);
1098 rpn.pn_path = rpn.pn_buf;
1099
1100 /*
1101 * Ensure the v_path pointing to correct vnode
1102 */
1103 VN_HOLD(vrootp);
1104 if (vrootp != rootdir)
1105 VN_HOLD(vrootp);
1106 if (lookuppnvp(&pn, &rpn, flags, NULL,
1107 &cmpvp, vrootp, vrootp, cr) == 0) {
1108
1109 if (VN_CMP(vp, cmpvp)) {
1110 VN_RELE(cmpvp);
1111
1112 complen = strlen(rpn.pn_path);
1113 bufloc -= complen;
1114 if (bufloc < buf) {
1115 err = ERANGE;
1116 goto out;
1117 }
1118 bcopy(rpn.pn_path, bufloc,
1119 complen);
1120 break;
1121 } else {
1122 VN_RELE(cmpvp);
1123 }
1124 }
1125 } else {
1126 mutex_exit(&vp->v_lock);
1127 }
1128 } else {
1129 mutex_exit(&vp->v_lock);
1130 }
1131
1132 /*
1133 * Shortcuts failed, search for this vnode in its parent. If
1134 * this is a mountpoint, then get the vnode underneath.
1135 */
1136 if (vp->v_flag & VROOT)
1137 vp = vn_under(vp);
1138 if ((err = VOP_LOOKUP(vp, "..", &pvp, &emptypn, 0, vrootp, cr,
1139 NULL, NULL, NULL)) != 0)
1140 goto out;
1141
1142 /*
1143 * With extended attributes, it's possible for a directory to
1144 * have a parent that is a regular file. Check for that here.
1145 */
1146 if (pvp->v_type != VDIR) {
1147 err = ENOTDIR;
1148 goto out;
1149 }
1150
1151 /*
1152 * If this is true, something strange has happened. This is
1153 * only true if we are the root of a filesystem, which should
1154 * have been caught by the check above.
1155 */
1156 if (VN_CMP(pvp, vp)) {
1157 err = ENOENT;
1158 goto out;
1159 }
1160
1161 /*
1162 * Check if we have read and search privilege so, that
1163 * we can lookup the path in the directory
1164 */
1165 vprivs = (flags & LOOKUP_CHECKREAD) ? VREAD | VEXEC : VEXEC;
1166 if ((err = VOP_ACCESS(pvp, vprivs, 0, cr, NULL)) != 0) {
1167 goto out;
1168 }
1169
1170 /*
1171 * Try to obtain the path component from dnlc cache
1172 * before searching through the directory.
1173 */
1174 if ((cmpvp = dnlc_reverse_lookup(vp, dbuf, dlen)) != NULL) {
1175 /*
1176 * If we got parent vnode as a result,
1177 * then the answered path is correct.
1178 */
1179 if (VN_CMP(cmpvp, pvp)) {
1180 VN_RELE(cmpvp);
1181 complen = strlen(dbuf);
1182 bufloc -= complen;
1183 if (bufloc <= buf) {
1184 err = ENAMETOOLONG;
1185 goto out;
1186 }
1187 bcopy(dbuf, bufloc, complen);
1188
1189 /* Prepend a slash to the current path */
1190 *--bufloc = '/';
1191
1192 /* And continue with the next component */
1193 VN_RELE(vp);
1194 vp = pvp;
1195 pvp = NULL;
1196 continue;
1197 } else {
1198 VN_RELE(cmpvp);
1199 }
1200 }
1201
1202 /*
1203 * Search the parent directory for the entry corresponding to
1204 * this vnode.
1205 */
1206 if ((err = dirfindvp(vrootp, pvp, vp, cr, dbuf, dlen, &dp))
1207 != 0)
1208 goto out;
1209 complen = strlen(dp->d_name);
1210 bufloc -= complen;
1211 if (bufloc <= buf) {
1212 err = ENAMETOOLONG;
1213 goto out;
1214 }
1215 bcopy(dp->d_name, bufloc, complen);
1216
1217 /* Prepend a slash to the current path. */
1218 *--bufloc = '/';
1219
1220 /* And continue with the next component */
1221 VN_RELE(vp);
1222 vp = pvp;
1223 pvp = NULL;
1224 }
1225
1226 /*
1227 * Place the path at the beginning of the buffer.
1228 */
1229 if (bufloc != buf)
1230 ovbcopy(bufloc, buf, buflen - (bufloc - buf));
1231
1232 out:
1233 /*
1234 * If the error was ESTALE and the current directory to look in
1235 * was the root for this lookup, the root for a mounted file
1236 * system, or the starting directory for lookups, then
1237 * return ENOENT instead of ESTALE. In this case, no recovery
1238 * is possible by the higher level. If ESTALE was returned for
1239 * some intermediate directory along the path, then recovery
1240 * is potentially possible and retrying from the higher level
1241 * will either correct the situation by purging stale cache
1242 * entries or eventually get back to the point where no recovery
1243 * is possible.
1244 */
1245 if (err == ESTALE &&
1246 (VN_CMP(vp, vrootp) || (vp->v_flag & VROOT) || vp == startvp))
1247 err = ENOENT;
1248
1249 kmem_free(dbuf, dlen);
1250 VN_RELE(vp);
1251 if (pvp)
1252 VN_RELE(pvp);
1253 pn_free(&pn);
1254 pn_free(&rpn);
1255
1256 return (err);
1257 }
1258
1259 /*
1260 * The additional flag, LOOKUP_CHECKREAD, is used to enforce artificial
1261 * constraints in order to be standards compliant. For example, if we have
1262 * the cached path of '/foo/bar', and '/foo' has permissions 100 (execute
1263 * only), then we can legitimately look up the path to the current working
1264 * directory without needing read permission. Existing standards tests,
1265 * however, assume that we are determining the path by repeatedly looking up
1266 * "..". We need to keep this behavior in order to maintain backwards
1267 * compatibility.
1268 */
1269 static int
1270 vnodetopath_common(vnode_t *vrootp, vnode_t *vp, char *buf, size_t buflen,
1271 cred_t *cr, int flags)
1272 {
1273 pathname_t pn, rpn;
1274 int ret, len;
1275 vnode_t *compvp, *pvp, *realvp;
1276 proc_t *p = curproc;
1277 char path[MAXNAMELEN];
1278 int doclose = 0;
1279
1280 /*
1281 * If vrootp is NULL, get the root for curproc. Callers with any other
1282 * requirements should pass in a different vrootp.
1283 */
1284 if (vrootp == NULL) {
1285 mutex_enter(&p->p_lock);
1286 if ((vrootp = PTOU(p)->u_rdir) == NULL)
1287 vrootp = rootdir;
1288 VN_HOLD(vrootp);
1289 mutex_exit(&p->p_lock);
1290 } else {
1291 VN_HOLD(vrootp);
1292 }
1293
1294 /*
1295 * This is to get around an annoying artifact of the /proc filesystem,
1296 * which is the behavior of {cwd/root}. Trying to resolve this path
1297 * will result in /proc/pid/cwd instead of whatever the real working
1298 * directory is. We can't rely on VOP_REALVP(), since that will break
1299 * lofs. The only difference between procfs and lofs is that opening
1300 * the file will return the underling vnode in the case of procfs.
1301 */
1302 if (vp->v_type == VDIR && VOP_REALVP(vp, &realvp, NULL) == 0 &&
1303 realvp != vp) {
1304 VN_HOLD(vp);
1305 if (VOP_OPEN(&vp, FREAD, cr, NULL) == 0)
1306 doclose = 1;
1307 else
1308 VN_RELE(vp);
1309 }
1310
1311 pn_alloc(&pn);
1312
1313 /*
1314 * Check to see if we have a cached path in the vnode.
1315 */
1316 mutex_enter(&vp->v_lock);
1317 if (vp->v_path != NULL) {
1318 (void) pn_set(&pn, vp->v_path);
1319 mutex_exit(&vp->v_lock);
1320
1321 pn_alloc(&rpn);
1322
1323 /* We should only cache absolute paths */
1324 ASSERT(pn.pn_buf[0] == '/');
1325
1326 /*
1327 * If we are in a zone or a chroot environment, then we have to
1328 * take additional steps, since the path to the root might not
1329 * be readable with the current credentials, even though the
1330 * process can legitmately access the file. In this case, we
1331 * do the following:
1332 *
1333 * lookuppnvp() with all privileges to get the resolved path.
1334 * call localpath() to get the local portion of the path, and
1335 * continue as normal.
1336 *
1337 * If the the conversion to a local path fails, then we continue
1338 * as normal. This is a heuristic to make process object file
1339 * paths available from within a zone. Because lofs doesn't
1340 * support page operations, the vnode stored in the seg_t is
1341 * actually the underlying real vnode, not the lofs node itself.
1342 * Most of the time, the lofs path is the same as the underlying
1343 * vnode (for example, /usr/lib/libc.so.1).
1344 */
1345 if (vrootp != rootdir) {
1346 char *local = NULL;
1347 VN_HOLD(rootdir);
1348 if (lookuppnvp(&pn, &rpn, FOLLOW,
1349 NULL, &compvp, rootdir, rootdir, kcred) == 0) {
1350 local = localpath(rpn.pn_path, vrootp,
1351 kcred);
1352 VN_RELE(compvp);
1353 }
1354
1355 /*
1356 * The original pn was changed through lookuppnvp().
1357 * Set it to local for next validation attempt.
1358 */
1359 if (local) {
1360 (void) pn_set(&pn, local);
1361 } else {
1362 goto notcached;
1363 }
1364 }
1365
1366 /*
1367 * We should have a local path at this point, so start the
1368 * search from the root of the current process.
1369 */
1370 VN_HOLD(vrootp);
1371 if (vrootp != rootdir)
1372 VN_HOLD(vrootp);
1373 ret = lookuppnvp(&pn, &rpn, FOLLOW | flags, NULL,
1374 &compvp, vrootp, vrootp, cr);
1375 if (ret == 0) {
1376 /*
1377 * Check to see if the returned vnode is the same as
1378 * the one we expect. If not, give up.
1379 */
1380 if (!vn_compare(vp, compvp) &&
1381 !vnode_match(vp, compvp, cr)) {
1382 VN_RELE(compvp);
1383 goto notcached;
1384 }
1385
1386 VN_RELE(compvp);
1387
1388 /*
1389 * Return the result.
1390 */
1391 if (buflen <= rpn.pn_pathlen)
1392 goto notcached;
1393
1394 bcopy(rpn.pn_path, buf, rpn.pn_pathlen + 1);
1395 pn_free(&pn);
1396 pn_free(&rpn);
1397 VN_RELE(vrootp);
1398 if (doclose) {
1399 (void) VOP_CLOSE(vp, FREAD, 1, 0, cr, NULL);
1400 VN_RELE(vp);
1401 }
1402 return (0);
1403 }
1404
1405 notcached:
1406 pn_free(&rpn);
1407 } else {
1408 mutex_exit(&vp->v_lock);
1409 }
1410
1411 pn_free(&pn);
1412
1413 if (PROC_IS_BRANDED(curproc)) {
1414 /*
1415 * If v_path doesn't work out and we're in a branded zone,
1416 * we're not going to bother doing more work here: because
1417 * directories from the global can be lofs mounted into odd
1418 * locations (e.g., /native in an lx zone), it is likely that
1419 * the DNLC reverse lookup will yield nothing. Indeed, the
1420 * only certainty is that the DNLC reverse lookup will be
1421 * exceedingly painful; we save ourselves the substantial
1422 * grief of scanning the entire DNLC and kick out with ENOENT
1423 * in this case.
1424 */
1425 ret = ENOENT;
1426 } else if (vp->v_type != VDIR) {
1427 /*
1428 * If we don't have a directory, try to find it in the dnlc via
1429 * reverse lookup. Once this is found, we can use the regular
1430 * directory search to find the full path.
1431 */
1432 if ((pvp = dnlc_reverse_lookup(vp, path, MAXNAMELEN)) != NULL) {
1433 /*
1434 * Check if we have read privilege so, that
1435 * we can lookup the path in the directory
1436 */
1437 ret = 0;
1438 if ((flags & LOOKUP_CHECKREAD)) {
1439 ret = VOP_ACCESS(pvp, VREAD, 0, cr, NULL);
1440 }
1441 if (ret == 0) {
1442 ret = dirtopath(vrootp, pvp, buf, buflen,
1443 flags, cr);
1444 }
1445 if (ret == 0) {
1446 len = strlen(buf);
1447 if (len + strlen(path) + 1 >= buflen) {
1448 ret = ENAMETOOLONG;
1449 } else {
1450 if (buf[len - 1] != '/')
1451 buf[len++] = '/';
1452 bcopy(path, buf + len,
1453 strlen(path) + 1);
1454 }
1455 }
1456
1457 VN_RELE(pvp);
1458 } else
1459 ret = ENOENT;
1460 } else
1461 ret = dirtopath(vrootp, vp, buf, buflen, flags, cr);
1462
1463 VN_RELE(vrootp);
1464 if (doclose) {
1465 (void) VOP_CLOSE(vp, FREAD, 1, 0, cr, NULL);
1466 VN_RELE(vp);
1467 }
1468
1469 return (ret);
1470 }
1471
1472 int
1473 vnodetopath(vnode_t *vrootp, vnode_t *vp, char *buf, size_t buflen, cred_t *cr)
1474 {
1475 return (vnodetopath_common(vrootp, vp, buf, buflen, cr, 0));
1476 }
1477
1478 int
1479 dogetcwd(char *buf, size_t buflen)
1480 {
1481 int ret;
1482 vnode_t *vp;
1483 vnode_t *compvp;
1484 refstr_t *cwd, *oldcwd;
1485 const char *value;
1486 pathname_t rpnp, pnp;
1487 proc_t *p = curproc;
1488
1489 /*
1490 * Check to see if there is a cached version of the cwd. If so, lookup
1491 * the cached value and make sure it is the same vnode.
1492 */
1493 mutex_enter(&p->p_lock);
1494 if ((cwd = PTOU(p)->u_cwd) != NULL)
1495 refstr_hold(cwd);
1496 vp = PTOU(p)->u_cdir;
1497 VN_HOLD(vp);
1498 mutex_exit(&p->p_lock);
1499
1500 /*
1501 * Make sure we have permission to access the current directory.
1502 */
1503 if ((ret = VOP_ACCESS(vp, VEXEC, 0, CRED(), NULL)) != 0) {
1504 if (cwd != NULL)
1505 refstr_rele(cwd);
1506 VN_RELE(vp);
1507 return (ret);
1508 }
1509
1510 if (cwd) {
1511 value = refstr_value(cwd);
1512 if ((ret = pn_get((char *)value, UIO_SYSSPACE, &pnp)) != 0) {
1513 refstr_rele(cwd);
1514 VN_RELE(vp);
1515 return (ret);
1516 }
1517
1518 pn_alloc(&rpnp);
1519
1520 if (lookuppn(&pnp, &rpnp, NO_FOLLOW, NULL, &compvp) == 0) {
1521
1522 if (VN_CMP(vp, compvp) &&
1523 strcmp(value, rpnp.pn_path) == 0) {
1524 VN_RELE(compvp);
1525 VN_RELE(vp);
1526 pn_free(&pnp);
1527 pn_free(&rpnp);
1528 if (strlen(value) + 1 > buflen) {
1529 refstr_rele(cwd);
1530 return (ENAMETOOLONG);
1531 }
1532 bcopy(value, buf, strlen(value) + 1);
1533 refstr_rele(cwd);
1534 return (0);
1535 }
1536
1537 VN_RELE(compvp);
1538 }
1539
1540 pn_free(&rpnp);
1541 pn_free(&pnp);
1542
1543 refstr_rele(cwd);
1544 }
1545
1546 ret = vnodetopath_common(NULL, vp, buf, buflen, CRED(),
1547 LOOKUP_CHECKREAD);
1548
1549 VN_RELE(vp);
1550
1551 /*
1552 * Store the new cwd and replace the existing cached copy.
1553 */
1554 if (ret == 0)
1555 cwd = refstr_alloc(buf);
1556 else
1557 cwd = NULL;
1558
1559 mutex_enter(&p->p_lock);
1560 oldcwd = PTOU(p)->u_cwd;
1561 PTOU(p)->u_cwd = cwd;
1562 mutex_exit(&p->p_lock);
1563
1564 if (oldcwd)
1565 refstr_rele(oldcwd);
1566
1567 return (ret);
1568 }