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