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 * Copyright 2007 Sun Microsystems, Inc. All rights reserved. 23 * Use is subject to license terms. 24 */ 25 26 /* Copyright (c) 1983, 1984, 1985, 1986, 1987, 1988, 1989 AT&T */ 27 /* All Rights Reserved */ 28 29 /* 30 * University Copyright- Copyright (c) 1982, 1986, 1988 31 * The Regents of the University of California 32 * All Rights Reserved 33 * 34 * University Acknowledgment- Portions of this document are derived from 35 * software developed by the University of California, Berkeley, and its 36 * contributors. 37 */ 38 39 40 #pragma ident "%Z%%M% %I% %E% SMI" 41 42 #include <sys/types.h> 43 #include <sys/param.h> 44 #include <sys/systm.h> 45 #include <sys/cpuvar.h> 46 #include <sys/errno.h> 47 #include <sys/cred.h> 48 #include <sys/user.h> 49 #include <sys/uio.h> 50 #include <sys/vfs.h> 51 #include <sys/vnode.h> 52 #include <sys/pathname.h> 53 #include <sys/proc.h> 54 #include <sys/vtrace.h> 55 #include <sys/sysmacros.h> 56 #include <sys/debug.h> 57 #include <sys/dirent.h> 58 #include <c2/audit.h> 59 #include <sys/zone.h> 60 #include <sys/dnlc.h> 61 #include <sys/fs/snode.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 enum symfollow followlink, 71 vnode_t **dirvpp, 72 vnode_t **compvpp) 73 { 74 return (lookupnameat(fnamep, seg, followlink, dirvpp, compvpp, NULL)); 75 } 76 77 78 /* 79 * Lookup the user file name, 80 * Handle allocation and freeing of pathname buffer, return error. 81 */ 82 int 83 lookupnameat( 84 char *fnamep, /* user pathname */ 85 enum uio_seg seg, /* addr space that name is in */ 86 enum symfollow 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 { 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 #ifdef C2_AUDIT 98 if (audit_active) 99 audit_lookupname(); 100 #endif 101 error = lookuppnat(&lookpn, NULL, followlink, 102 dirvpp, compvpp, startvp); 103 } 104 if (error == ENAMETOOLONG) { 105 /* 106 * This thread used a pathname > TYPICALMAXPATHLEN bytes long. 107 */ 108 if (error = pn_get(fnamep, seg, &lookpn)) 109 return (error); 110 error = lookuppnat(&lookpn, NULL, followlink, 111 dirvpp, compvpp, startvp); 112 pn_free(&lookpn); 113 } 114 115 return (error); 116 } 117 118 /* 119 * Lookup the user file name from a given vp, 120 */ 121 int 122 lookuppn( 123 struct pathname *pnp, 124 struct pathname *rpnp, 125 enum symfollow followlink, 126 vnode_t **dirvpp, 127 vnode_t **compvpp) 128 { 129 return (lookuppnat(pnp, rpnp, followlink, dirvpp, compvpp, NULL)); 130 } 131 132 int 133 lookuppnat( 134 struct pathname *pnp, /* pathname to lookup */ 135 struct pathname *rpnp, /* if non-NULL, return resolved path */ 136 enum symfollow followlink, /* (don't) follow sym links */ 137 vnode_t **dirvpp, /* ptr for parent vnode */ 138 vnode_t **compvpp, /* ptr for entry vnode */ 139 vnode_t *startvp) /* start search from this vp */ 140 { 141 vnode_t *vp; /* current directory vp */ 142 vnode_t *rootvp; 143 proc_t *p = curproc; 144 145 if (pnp->pn_pathlen == 0) 146 return (ENOENT); 147 148 mutex_enter(&p->p_lock); /* for u_rdir and u_cdir */ 149 if ((rootvp = PTOU(p)->u_rdir) == NULL) 150 rootvp = rootdir; 151 else if (rootvp != rootdir) /* no need to VN_HOLD rootdir */ 152 VN_HOLD(rootvp); 153 154 if (pnp->pn_path[0] == '/') { 155 vp = rootvp; 156 } else { 157 vp = (startvp == NULL) ? PTOU(p)->u_cdir : startvp; 158 } 159 VN_HOLD(vp); 160 mutex_exit(&p->p_lock); 161 162 /* 163 * Skip over leading slashes 164 */ 165 if (pnp->pn_path[0] == '/') { 166 do { 167 pnp->pn_path++; 168 pnp->pn_pathlen--; 169 } while (pnp->pn_path[0] == '/'); 170 } 171 172 return (lookuppnvp(pnp, rpnp, followlink, dirvpp, 173 compvpp, rootvp, vp, CRED())); 174 } 175 176 /* Private flag to do our getcwd() dirty work */ 177 #define LOOKUP_CHECKREAD 0x10 178 #define LOOKUP_MASK (~LOOKUP_CHECKREAD) 179 180 /* 181 * Starting at current directory, translate pathname pnp to end. 182 * Leave pathname of final component in pnp, return the vnode 183 * for the final component in *compvpp, and return the vnode 184 * for the parent of the final component in dirvpp. 185 * 186 * This is the central routine in pathname translation and handles 187 * multiple components in pathnames, separating them at /'s. It also 188 * implements mounted file systems and processes symbolic links. 189 * 190 * vp is the vnode where the directory search should start. 191 * 192 * Reference counts: vp must be held prior to calling this function. rootvp 193 * should only be held if rootvp != rootdir. 194 */ 195 int 196 lookuppnvp( 197 struct pathname *pnp, /* pathname to lookup */ 198 struct pathname *rpnp, /* if non-NULL, return resolved path */ 199 int flags, /* follow symlinks */ 200 vnode_t **dirvpp, /* ptr for parent vnode */ 201 vnode_t **compvpp, /* ptr for entry vnode */ 202 vnode_t *rootvp, /* rootvp */ 203 vnode_t *vp, /* directory to start search at */ 204 cred_t *cr) /* user's credential */ 205 { 206 vnode_t *cvp; /* current component vp */ 207 vnode_t *tvp; /* addressable temp ptr */ 208 char component[MAXNAMELEN]; /* buffer for component (incl null) */ 209 int error; 210 int nlink; 211 int lookup_flags; 212 vnode_t *startvp; 213 vnode_t *zonevp = curproc->p_zone->zone_rootvp; /* zone root */ 214 int must_be_directory = 0; 215 boolean_t retry_with_kcred = B_FALSE; 216 217 CPU_STATS_ADDQ(CPU, sys, namei, 1); 218 nlink = 0; 219 cvp = NULL; 220 if (rpnp) 221 rpnp->pn_pathlen = 0; 222 lookup_flags = dirvpp ? LOOKUP_DIR : 0; 223 #ifdef C2_AUDIT 224 if (audit_active) 225 audit_anchorpath(pnp, vp == rootvp); 226 #endif 227 228 /* 229 * Eliminate any trailing slashes in the pathname. 230 * If there are any, we must follow all symlinks. 231 * Also, we must guarantee that the last component is a directory. 232 */ 233 if (pn_fixslash(pnp)) { 234 flags |= FOLLOW; 235 must_be_directory = 1; 236 } 237 238 startvp = vp; 239 next: 240 /* 241 * Make sure we have a directory. 242 */ 243 if (vp->v_type != VDIR) { 244 error = ENOTDIR; 245 goto bad; 246 } 247 248 if (rpnp && VN_CMP(vp, rootvp)) 249 (void) pn_set(rpnp, "/"); 250 251 /* 252 * Process the next component of the pathname. 253 */ 254 if (error = pn_getcomponent(pnp, component)) { 255 #ifdef C2_AUDIT 256 if (audit_active) 257 audit_addcomponent(pnp); 258 #endif 259 goto bad; 260 } 261 262 /* 263 * Handle "..": two special cases. 264 * 1. If we're at the root directory (e.g. after chroot or 265 * zone_enter) then change ".." to "." so we can't get 266 * out of this subtree. 267 * 2. If this vnode is the root of a mounted file system, 268 * then replace it with the vnode that was mounted on 269 * so that we take the ".." in the other file system. 270 */ 271 if (component[0] == '.' && component[1] == '.' && component[2] == 0) { 272 checkforroot: 273 if (VN_CMP(vp, rootvp) || VN_CMP(vp, zonevp)) { 274 component[1] = '\0'; 275 } else if (vp->v_flag & VROOT) { 276 vfs_t *vfsp; 277 cvp = vp; 278 279 /* 280 * While we deal with the vfs pointer from the vnode 281 * the filesystem could have been forcefully unmounted 282 * and the vnode's v_vfsp could have been invalidated 283 * by VFS_UNMOUNT. Hence, we cache v_vfsp and use it 284 * with vfs_rlock_wait/vfs_unlock. 285 * It is safe to use the v_vfsp even it is freed by 286 * VFS_UNMOUNT because vfs_rlock_wait/vfs_unlock 287 * do not dereference v_vfsp. It is just used as a 288 * magic cookie. 289 * One more corner case here is the memory getting 290 * reused for another vfs structure. In this case 291 * lookuppnvp's vfs_rlock_wait will succeed, domount's 292 * vfs_lock will fail and domount will bail out with an 293 * error (EBUSY). 294 */ 295 vfsp = cvp->v_vfsp; 296 297 /* 298 * This lock is used to synchronize 299 * mounts/unmounts and lookups. 300 * Threads doing mounts/unmounts hold the 301 * writers version vfs_lock_wait(). 302 */ 303 304 vfs_rlock_wait(vfsp); 305 306 /* 307 * If this vnode is on a file system that 308 * has been forcibly unmounted, 309 * we can't proceed. Cancel this operation 310 * and return EIO. 311 * 312 * vfs_vnodecovered is NULL if unmounted. 313 * Currently, nfs uses VFS_UNMOUNTED to 314 * check if it's a forced-umount. Keep the 315 * same checking here as well even though it 316 * may not be needed. 317 */ 318 if (((vp = cvp->v_vfsp->vfs_vnodecovered) == NULL) || 319 (cvp->v_vfsp->vfs_flag & VFS_UNMOUNTED)) { 320 vfs_unlock(vfsp); 321 VN_RELE(cvp); 322 return (EIO); 323 } 324 VN_HOLD(vp); 325 vfs_unlock(vfsp); 326 VN_RELE(cvp); 327 cvp = NULL; 328 /* 329 * Crossing mount points. For eg: We are doing 330 * a lookup of ".." for file systems root vnode 331 * mounted here, and VOP_LOOKUP() (with covered vnode) 332 * will be on underlying file systems mount point 333 * vnode. Set retry_with_kcred flag as we might end 334 * up doing VOP_LOOKUP() with kcred if required. 335 */ 336 retry_with_kcred = B_TRUE; 337 goto checkforroot; 338 } 339 } 340 341 /* 342 * LOOKUP_CHECKREAD is a private flag used by vnodetopath() to indicate 343 * that we need to have read permission on every directory in the entire 344 * path. This is used to ensure that a forward-lookup of a cached value 345 * has the same effect as a reverse-lookup when the cached value cannot 346 * be found. 347 */ 348 if ((flags & LOOKUP_CHECKREAD) && 349 (error = VOP_ACCESS(vp, VREAD, 0, cr)) != 0) 350 goto bad; 351 352 /* 353 * Perform a lookup in the current directory. 354 */ 355 error = VOP_LOOKUP(vp, component, &tvp, pnp, lookup_flags, 356 rootvp, cr); 357 358 /* 359 * Retry with kcred - If crossing mount points & error is EACCES. 360 * 361 * If we are crossing mount points here and doing ".." lookup, 362 * VOP_LOOKUP() might fail if the underlying file systems 363 * mount point has no execute permission. In cases like these, 364 * we retry VOP_LOOKUP() by giving as much privilage as possible 365 * by passing kcred credentials. 366 * 367 * In case of hierarchical file systems, passing kcred still may 368 * or may not work. 369 * For eg: UFS FS --> Mount NFS FS --> Again mount UFS on some 370 * directory inside NFS FS. 371 */ 372 if ((error == EACCES) && retry_with_kcred) 373 error = VOP_LOOKUP(vp, component, &tvp, pnp, lookup_flags, 374 rootvp, zone_kcred()); 375 376 cvp = tvp; 377 if (error) { 378 cvp = NULL; 379 /* 380 * On error, return hard error if 381 * (a) we're not at the end of the pathname yet, or 382 * (b) the caller didn't want the parent directory, or 383 * (c) we failed for some reason other than a missing entry. 384 */ 385 if (pn_pathleft(pnp) || dirvpp == NULL || error != ENOENT) 386 goto bad; 387 #ifdef C2_AUDIT 388 if (audit_active) { /* directory access */ 389 if (error = audit_savepath(pnp, vp, error, cr)) 390 goto bad_noaudit; 391 } 392 #endif 393 pn_setlast(pnp); 394 /* 395 * We inform the caller that the desired entry must be 396 * a directory by adding a '/' to the component name. 397 */ 398 if (must_be_directory && (error = pn_addslash(pnp)) != 0) 399 goto bad; 400 *dirvpp = vp; 401 if (compvpp != NULL) 402 *compvpp = NULL; 403 if (rootvp != rootdir) 404 VN_RELE(rootvp); 405 return (0); 406 } 407 408 /* 409 * Traverse mount points. 410 * XXX why don't we need to hold a read lock here (call vn_vfsrlock)? 411 * What prevents a concurrent update to v_vfsmountedhere? 412 * Possible answer: if mounting, we might not see the mount 413 * if it is concurrently coming into existence, but that's 414 * really not much different from the thread running a bit slower. 415 * If unmounting, we may get into traverse() when we shouldn't, 416 * but traverse() will catch this case for us. 417 * (For this to work, fetching v_vfsmountedhere had better 418 * be atomic!) 419 */ 420 if (vn_mountedvfs(cvp) != NULL) { 421 tvp = cvp; 422 if ((error = traverse(&tvp)) != 0) { 423 /* 424 * It is required to assign cvp here, because 425 * traverse() will return a held vnode which 426 * may different than the vnode that was passed 427 * in (even in the error case). If traverse() 428 * changes the vnode it releases the original, 429 * and holds the new one. 430 */ 431 cvp = tvp; 432 goto bad; 433 } 434 cvp = tvp; 435 } 436 437 /* 438 * If we hit a symbolic link and there is more path to be 439 * translated or this operation does not wish to apply 440 * to a link, then place the contents of the link at the 441 * front of the remaining pathname. 442 */ 443 if (cvp->v_type == VLNK && ((flags & FOLLOW) || pn_pathleft(pnp))) { 444 struct pathname linkpath; 445 #ifdef C2_AUDIT 446 if (audit_active) { 447 if (error = audit_pathcomp(pnp, cvp, cr)) 448 goto bad; 449 } 450 #endif 451 452 if (++nlink > MAXSYMLINKS) { 453 error = ELOOP; 454 goto bad; 455 } 456 pn_alloc(&linkpath); 457 if (error = pn_getsymlink(cvp, &linkpath, cr)) { 458 pn_free(&linkpath); 459 goto bad; 460 } 461 462 #ifdef C2_AUDIT 463 if (audit_active) 464 audit_symlink(pnp, &linkpath); 465 #endif /* C2_AUDIT */ 466 467 if (pn_pathleft(&linkpath) == 0) 468 (void) pn_set(&linkpath, "."); 469 error = pn_insert(pnp, &linkpath, strlen(component)); 470 pn_free(&linkpath); 471 if (error) 472 goto bad; 473 VN_RELE(cvp); 474 cvp = NULL; 475 if (pnp->pn_pathlen == 0) { 476 error = ENOENT; 477 goto bad; 478 } 479 if (pnp->pn_path[0] == '/') { 480 do { 481 pnp->pn_path++; 482 pnp->pn_pathlen--; 483 } while (pnp->pn_path[0] == '/'); 484 VN_RELE(vp); 485 vp = rootvp; 486 VN_HOLD(vp); 487 } 488 #ifdef C2_AUDIT 489 if (audit_active) 490 audit_anchorpath(pnp, vp == rootvp); 491 #endif 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 error = copystr(component, 525 rpnp->pn_path + rpnp->pn_pathlen, 526 rpnp->pn_bufsize - rpnp->pn_pathlen, &len); 527 if (error) /* copystr() returns ENAMETOOLONG */ 528 goto bad; 529 rpnp->pn_pathlen += (len - 1); 530 ASSERT(rpnp->pn_bufsize > rpnp->pn_pathlen); 531 } 532 } 533 534 /* 535 * If no more components, return last directory (if wanted) and 536 * last component (if wanted). 537 */ 538 if (pn_pathleft(pnp) == 0) { 539 /* 540 * If there was a trailing slash in the pathname, 541 * make sure the last component is a directory. 542 */ 543 if (must_be_directory && cvp->v_type != VDIR) { 544 error = ENOTDIR; 545 goto bad; 546 } 547 if (dirvpp != NULL) { 548 /* 549 * Check that we have the real parent and not 550 * an alias of the last component. 551 */ 552 if (vn_compare(vp, cvp)) { 553 #ifdef C2_AUDIT 554 if (audit_active) 555 (void) audit_savepath(pnp, cvp, 556 EINVAL, cr); 557 #endif 558 pn_setlast(pnp); 559 VN_RELE(vp); 560 VN_RELE(cvp); 561 if (rootvp != rootdir) 562 VN_RELE(rootvp); 563 return (EINVAL); 564 } 565 #ifdef C2_AUDIT 566 if (audit_active) { 567 if (error = audit_pathcomp(pnp, vp, cr)) 568 goto bad; 569 } 570 #endif 571 *dirvpp = vp; 572 } else 573 VN_RELE(vp); 574 #ifdef C2_AUDIT 575 if (audit_active) 576 (void) audit_savepath(pnp, cvp, 0, cr); 577 #endif 578 if (pnp->pn_path == pnp->pn_buf) 579 (void) pn_set(pnp, "."); 580 else 581 pn_setlast(pnp); 582 if (rpnp) { 583 if (VN_CMP(cvp, rootvp)) 584 (void) pn_set(rpnp, "/"); 585 else if (rpnp->pn_pathlen == 0) 586 (void) pn_set(rpnp, "."); 587 } 588 589 if (compvpp != NULL) 590 *compvpp = cvp; 591 else 592 VN_RELE(cvp); 593 if (rootvp != rootdir) 594 VN_RELE(rootvp); 595 return (0); 596 } 597 598 #ifdef C2_AUDIT 599 if (audit_active) { 600 if (error = audit_pathcomp(pnp, cvp, cr)) 601 goto bad; 602 } 603 #endif 604 605 /* 606 * Skip over slashes from end of last component. 607 */ 608 while (pnp->pn_path[0] == '/') { 609 pnp->pn_path++; 610 pnp->pn_pathlen--; 611 } 612 613 /* 614 * Searched through another level of directory: 615 * release previous directory handle and save new (result 616 * of lookup) as current directory. 617 */ 618 VN_RELE(vp); 619 vp = cvp; 620 cvp = NULL; 621 goto next; 622 623 bad: 624 #ifdef C2_AUDIT 625 if (audit_active) /* reached end of path */ 626 (void) audit_savepath(pnp, cvp, error, cr); 627 bad_noaudit: 628 #endif 629 /* 630 * Error. Release vnodes and return. 631 */ 632 if (cvp) 633 VN_RELE(cvp); 634 /* 635 * If the error was ESTALE and the current directory to look in 636 * was the root for this lookup, the root for a mounted file 637 * system, or the starting directory for lookups, then 638 * return ENOENT instead of ESTALE. In this case, no recovery 639 * is possible by the higher level. If ESTALE was returned for 640 * some intermediate directory along the path, then recovery 641 * is potentially possible and retrying from the higher level 642 * will either correct the situation by purging stale cache 643 * entries or eventually get back to the point where no recovery 644 * is possible. 645 */ 646 if (error == ESTALE && 647 (VN_CMP(vp, rootvp) || (vp->v_flag & VROOT) || vp == startvp)) 648 error = ENOENT; 649 VN_RELE(vp); 650 if (rootvp != rootdir) 651 VN_RELE(rootvp); 652 return (error); 653 } 654 655 /* 656 * Traverse a mount point. Routine accepts a vnode pointer as a reference 657 * parameter and performs the indirection, releasing the original vnode. 658 */ 659 int 660 traverse(vnode_t **cvpp) 661 { 662 int error = 0; 663 vnode_t *cvp; 664 vnode_t *tvp; 665 vfs_t *vfsp; 666 667 cvp = *cvpp; 668 669 /* 670 * If this vnode is mounted on, then we transparently indirect 671 * to the vnode which is the root of the mounted file system. 672 * Before we do this we must check that an unmount is not in 673 * progress on this vnode. 674 */ 675 676 for (;;) { 677 /* 678 * Try to read lock the vnode. If this fails because 679 * the vnode is already write locked, then check to 680 * see whether it is the current thread which locked 681 * the vnode. If it is not, then read lock the vnode 682 * by waiting to acquire the lock. 683 * 684 * The code path in domount() is an example of support 685 * which needs to look up two pathnames and locks one 686 * of them in between the two lookups. 687 */ 688 error = vn_vfsrlock(cvp); 689 if (error) { 690 if (!vn_vfswlock_held(cvp)) 691 error = vn_vfsrlock_wait(cvp); 692 if (error != 0) { 693 /* 694 * lookuppn() expects a held vnode to be 695 * returned because it promptly calls 696 * VN_RELE after the error return 697 */ 698 *cvpp = cvp; 699 return (error); 700 } 701 } 702 703 /* 704 * Reached the end of the mount chain? 705 */ 706 vfsp = vn_mountedvfs(cvp); 707 if (vfsp == NULL) { 708 vn_vfsunlock(cvp); 709 break; 710 } 711 712 /* 713 * The read lock must be held across the call to VFS_ROOT() to 714 * prevent a concurrent unmount from destroying the vfs. 715 */ 716 error = VFS_ROOT(vfsp, &tvp); 717 vn_vfsunlock(cvp); 718 719 if (error) 720 break; 721 722 VN_RELE(cvp); 723 724 cvp = tvp; 725 } 726 727 *cvpp = cvp; 728 return (error); 729 } 730 731 /* 732 * Return the lowermost vnode if this is a mountpoint. 733 */ 734 static vnode_t * 735 vn_under(vnode_t *vp) 736 { 737 vnode_t *uvp; 738 vfs_t *vfsp; 739 740 while (vp->v_flag & VROOT) { 741 742 vfsp = vp->v_vfsp; 743 vfs_rlock_wait(vfsp); 744 if ((uvp = vfsp->vfs_vnodecovered) == NULL || 745 (vfsp->vfs_flag & VFS_UNMOUNTED)) { 746 vfs_unlock(vfsp); 747 break; 748 } 749 VN_HOLD(uvp); 750 vfs_unlock(vfsp); 751 VN_RELE(vp); 752 vp = uvp; 753 } 754 755 return (vp); 756 } 757 758 static int 759 vnode_match(vnode_t *v1, vnode_t *v2, cred_t *cr) 760 { 761 vattr_t v1attr, v2attr; 762 763 /* 764 * If we have a device file, check to see if is a cloned open of the 765 * same device. For self-cloning devices, the major numbers will match. 766 * For devices cloned through the 'clone' driver, the minor number of 767 * the source device will be the same as the major number of the cloned 768 * device. 769 */ 770 if ((v1->v_type == VCHR || v1->v_type == VBLK) && 771 v1->v_type == v2->v_type) { 772 if ((spec_is_selfclone(v1) || spec_is_selfclone(v2)) && 773 getmajor(v1->v_rdev) == getmajor(v2->v_rdev)) 774 return (1); 775 776 if (spec_is_clone(v1) && 777 getmajor(v1->v_rdev) == getminor(v2->v_rdev)) 778 return (1); 779 780 if (spec_is_clone(v2) && 781 getmajor(v2->v_rdev) == getminor(v1->v_rdev)) 782 return (1); 783 } 784 785 v1attr.va_mask = v2attr.va_mask = AT_TYPE; 786 787 /* 788 * This check for symbolic links handles the pseudo-symlinks in procfs. 789 * These particular links have v_type of VDIR, but the attributes have a 790 * type of VLNK. We need to avoid these links because otherwise if we 791 * are currently in '/proc/self/fd', then '/proc/self/cwd' will compare 792 * as the same vnode. 793 */ 794 if (VOP_GETATTR(v1, &v1attr, 0, cr) != 0 || 795 VOP_GETATTR(v2, &v2attr, 0, cr) != 0 || 796 v1attr.va_type == VLNK || v2attr.va_type == VLNK) 797 return (0); 798 799 v1attr.va_mask = v2attr.va_mask = AT_TYPE | AT_FSID | AT_NODEID; 800 801 if (VOP_GETATTR(v1, &v1attr, ATTR_REAL, cr) != 0 || 802 VOP_GETATTR(v2, &v2attr, ATTR_REAL, cr) != 0) 803 return (0); 804 805 return (v1attr.va_fsid == v2attr.va_fsid && 806 v1attr.va_nodeid == v2attr.va_nodeid); 807 } 808 809 810 /* 811 * Find the entry in the directory corresponding to the target vnode. 812 */ 813 int 814 dirfindvp(vnode_t *vrootp, vnode_t *dvp, vnode_t *tvp, cred_t *cr, char *dbuf, 815 size_t dlen, dirent64_t **rdp) 816 { 817 size_t dbuflen; 818 struct iovec iov; 819 struct uio uio; 820 int error; 821 int eof; 822 vnode_t *cmpvp; 823 struct dirent64 *dp; 824 pathname_t pnp; 825 826 ASSERT(dvp->v_type == VDIR); 827 828 /* 829 * This is necessary because of the strange semantics of VOP_LOOKUP(). 830 */ 831 bzero(&pnp, sizeof (pnp)); 832 833 eof = 0; 834 835 uio.uio_iov = &iov; 836 uio.uio_iovcnt = 1; 837 uio.uio_segflg = UIO_SYSSPACE; 838 uio.uio_fmode = 0; 839 uio.uio_extflg = UIO_COPY_CACHED; 840 uio.uio_loffset = 0; 841 842 if ((error = VOP_ACCESS(dvp, VREAD, 0, cr)) != 0) 843 return (error); 844 845 while (!eof) { 846 uio.uio_resid = dlen; 847 iov.iov_base = dbuf; 848 iov.iov_len = dlen; 849 850 (void) VOP_RWLOCK(dvp, V_WRITELOCK_FALSE, NULL); 851 error = VOP_READDIR(dvp, &uio, cr, &eof); 852 VOP_RWUNLOCK(dvp, V_WRITELOCK_FALSE, NULL); 853 854 dbuflen = dlen - uio.uio_resid; 855 856 if (error || dbuflen == 0) 857 break; 858 859 dp = (dirent64_t *)dbuf; 860 while ((intptr_t)dp < (intptr_t)dbuf + dbuflen) { 861 /* 862 * Ignore '.' and '..' entries 863 */ 864 if (strcmp(dp->d_name, ".") == 0 || 865 strcmp(dp->d_name, "..") == 0) { 866 dp = (dirent64_t *)((intptr_t)dp + 867 dp->d_reclen); 868 continue; 869 } 870 871 error = VOP_LOOKUP(dvp, dp->d_name, &cmpvp, &pnp, 0, 872 vrootp, cr); 873 874 /* 875 * We only want to bail out if there was an error other 876 * than ENOENT. Otherwise, it could be that someone 877 * just removed an entry since the readdir() call, and 878 * the entry we want is further on in the directory. 879 */ 880 if (error == 0) { 881 if (vnode_match(tvp, cmpvp, cr)) { 882 VN_RELE(cmpvp); 883 *rdp = dp; 884 return (0); 885 } 886 887 VN_RELE(cmpvp); 888 } else if (error != ENOENT) { 889 return (error); 890 } 891 892 dp = (dirent64_t *)((intptr_t)dp + dp->d_reclen); 893 } 894 } 895 896 /* 897 * Something strange has happened, this directory does not contain the 898 * specified vnode. This should never happen in the normal case, since 899 * we ensured that dvp is the parent of vp. This is possible in some 900 * rare conditions (races and the special .zfs directory). 901 */ 902 if (error == 0) { 903 error = VOP_LOOKUP(dvp, ".zfs", &cmpvp, &pnp, 0, vrootp, cr); 904 if (error == 0) { 905 if (vnode_match(tvp, cmpvp, cr)) { 906 (void) strcpy(dp->d_name, ".zfs"); 907 dp->d_reclen = strlen(".zfs"); 908 dp->d_off = 2; 909 dp->d_ino = 1; 910 *rdp = dp; 911 } else { 912 error = ENOENT; 913 } 914 VN_RELE(cmpvp); 915 } 916 } 917 918 return (error); 919 } 920 921 /* 922 * Given a global path (from rootdir), and a vnode that is the current root, 923 * return the portion of the path that is beneath the current root or NULL on 924 * failure. The path MUST be a resolved path (no '..' entries or symlinks), 925 * otherwise this function will fail. 926 */ 927 static char * 928 localpath(char *path, struct vnode *vrootp, cred_t *cr) 929 { 930 vnode_t *vp; 931 vnode_t *cvp; 932 char component[MAXNAMELEN]; 933 char *ret = NULL; 934 pathname_t pn; 935 936 /* 937 * We use vn_compare() instead of VN_CMP() in order to detect lofs 938 * mounts and stacked vnodes. 939 */ 940 if (vn_compare(vrootp, rootdir)) 941 return (path); 942 943 if (pn_get(path, UIO_SYSSPACE, &pn) != 0) 944 return (NULL); 945 946 vp = rootdir; 947 VN_HOLD(vp); 948 949 while (pn_pathleft(&pn)) { 950 pn_skipslash(&pn); 951 952 if (pn_getcomponent(&pn, component) != 0) 953 break; 954 955 if (vn_ismntpt(vp) && traverse(&vp) != 0) 956 break; 957 958 if (VOP_LOOKUP(vp, component, &cvp, &pn, 0, rootdir, cr) != 0) 959 break; 960 961 VN_RELE(vp); 962 vp = cvp; 963 964 if (vn_compare(vp, vrootp)) { 965 ret = path + (pn.pn_path - pn.pn_buf); 966 break; 967 } 968 } 969 970 VN_RELE(vp); 971 pn_free(&pn); 972 973 return (ret); 974 } 975 976 /* 977 * Given a directory, return the full, resolved path. This looks up "..", 978 * searches for the given vnode in the parent, appends the component, etc. It 979 * is used to implement vnodetopath() and getcwd() when the cached path fails 980 * (or vfs_vnode_path is not set). 981 */ 982 static int 983 dirtopath(vnode_t *vrootp, vnode_t *vp, char *buf, size_t buflen, cred_t *cr) 984 { 985 pathname_t pn, rpn, emptypn; 986 vnode_t *cmpvp, *pvp = NULL; 987 vnode_t *startvp = vp; 988 int err = 0; 989 size_t complen; 990 char *dbuf; 991 dirent64_t *dp; 992 char *bufloc; 993 size_t dlen = DIRENT64_RECLEN(MAXPATHLEN); 994 refstr_t *mntpt; 995 996 /* Operation only allowed on directories */ 997 ASSERT(vp->v_type == VDIR); 998 999 /* We must have at least enough space for "/" */ 1000 if (buflen < 2) 1001 return (ENAMETOOLONG); 1002 1003 /* Start at end of string with terminating null */ 1004 bufloc = &buf[buflen - 1]; 1005 *bufloc = '\0'; 1006 1007 pn_alloc(&pn); 1008 pn_alloc(&rpn); 1009 dbuf = kmem_alloc(dlen, KM_SLEEP); 1010 bzero(&emptypn, sizeof (emptypn)); 1011 1012 /* 1013 * Begin with an additional reference on vp. This will be decremented 1014 * during the loop. 1015 */ 1016 VN_HOLD(vp); 1017 1018 for (;;) { 1019 /* 1020 * Return if we've reached the root. If the buffer is empty, 1021 * return '/'. We explicitly don't use vn_compare(), since it 1022 * compares the real vnodes. A lofs mount of '/' would produce 1023 * incorrect results otherwise. 1024 */ 1025 if (VN_CMP(vrootp, vp)) { 1026 if (*bufloc == '\0') 1027 *--bufloc = '/'; 1028 break; 1029 } 1030 1031 /* 1032 * If we've reached the VFS root, something has gone wrong. We 1033 * should have reached the root in the above check. The only 1034 * explantation is that 'vp' is not contained withing the given 1035 * root, in which case we return EPERM. 1036 */ 1037 if (VN_CMP(rootdir, vp)) { 1038 err = EPERM; 1039 goto out; 1040 } 1041 1042 /* 1043 * Shortcut: see if this vnode is a mountpoint. If so, 1044 * grab the path information from the vfs_t. 1045 */ 1046 if (vp->v_flag & VROOT) { 1047 1048 mntpt = vfs_getmntpoint(vp->v_vfsp); 1049 if ((err = pn_set(&pn, (char *)refstr_value(mntpt))) 1050 == 0) { 1051 refstr_rele(mntpt); 1052 rpn.pn_path = rpn.pn_buf; 1053 1054 /* 1055 * Ensure the mointpoint still exists. 1056 */ 1057 VN_HOLD(vrootp); 1058 if (vrootp != rootdir) 1059 VN_HOLD(vrootp); 1060 if (lookuppnvp(&pn, &rpn, 0, NULL, 1061 &cmpvp, vrootp, vrootp, cr) == 0) { 1062 1063 if (VN_CMP(vp, cmpvp)) { 1064 VN_RELE(cmpvp); 1065 1066 complen = strlen(rpn.pn_path); 1067 bufloc -= complen; 1068 if (bufloc < buf) { 1069 err = ERANGE; 1070 goto out; 1071 } 1072 bcopy(rpn.pn_path, bufloc, 1073 complen); 1074 break; 1075 } else { 1076 VN_RELE(cmpvp); 1077 } 1078 } 1079 } else { 1080 refstr_rele(mntpt); 1081 } 1082 } 1083 1084 /* 1085 * Shortcuts failed, search for this vnode in its parent. If 1086 * this is a mountpoint, then get the vnode underneath. 1087 */ 1088 if (vp->v_flag & VROOT) 1089 vp = vn_under(vp); 1090 if ((err = VOP_LOOKUP(vp, "..", &pvp, &emptypn, 0, vrootp, cr)) 1091 != 0) 1092 goto out; 1093 1094 /* 1095 * With extended attributes, it's possible for a directory to 1096 * have a parent that is a regular file. Check for that here. 1097 */ 1098 if (pvp->v_type != VDIR) { 1099 err = ENOTDIR; 1100 goto out; 1101 } 1102 1103 /* 1104 * If this is true, something strange has happened. This is 1105 * only true if we are the root of a filesystem, which should 1106 * have been caught by the check above. 1107 */ 1108 if (VN_CMP(pvp, vp)) { 1109 err = ENOENT; 1110 goto out; 1111 } 1112 1113 /* 1114 * Search the parent directory for the entry corresponding to 1115 * this vnode. 1116 */ 1117 if ((err = dirfindvp(vrootp, pvp, vp, cr, dbuf, dlen, &dp)) 1118 != 0) 1119 goto out; 1120 complen = strlen(dp->d_name); 1121 bufloc -= complen; 1122 if (bufloc <= buf) { 1123 err = ENAMETOOLONG; 1124 goto out; 1125 } 1126 bcopy(dp->d_name, bufloc, complen); 1127 1128 /* Prepend a slash to the current path. */ 1129 *--bufloc = '/'; 1130 1131 /* And continue with the next component */ 1132 VN_RELE(vp); 1133 vp = pvp; 1134 pvp = NULL; 1135 } 1136 1137 /* 1138 * Place the path at the beginning of the buffer. 1139 */ 1140 if (bufloc != buf) 1141 ovbcopy(bufloc, buf, buflen - (bufloc - buf)); 1142 1143 out: 1144 /* 1145 * If the error was ESTALE and the current directory to look in 1146 * was the root for this lookup, the root for a mounted file 1147 * system, or the starting directory for lookups, then 1148 * return ENOENT instead of ESTALE. In this case, no recovery 1149 * is possible by the higher level. If ESTALE was returned for 1150 * some intermediate directory along the path, then recovery 1151 * is potentially possible and retrying from the higher level 1152 * will either correct the situation by purging stale cache 1153 * entries or eventually get back to the point where no recovery 1154 * is possible. 1155 */ 1156 if (err == ESTALE && 1157 (VN_CMP(vp, vrootp) || (vp->v_flag & VROOT) || vp == startvp)) 1158 err = ENOENT; 1159 1160 kmem_free(dbuf, dlen); 1161 VN_RELE(vp); 1162 if (pvp) 1163 VN_RELE(pvp); 1164 pn_free(&pn); 1165 pn_free(&rpn); 1166 1167 return (err); 1168 } 1169 1170 /* 1171 * The additional flag, LOOKUP_CHECKREAD, is ued to enforce artificial 1172 * constraints in order to be standards compliant. For example, if we have 1173 * the cached path of '/foo/bar', and '/foo' has permissions 100 (execute 1174 * only), then we can legitimately look up the path to the current working 1175 * directory without needing read permission. Existing standards tests, 1176 * however, assume that we are determining the path by repeatedly looking up 1177 * "..". We need to keep this behavior in order to maintain backwards 1178 * compatibility. 1179 */ 1180 static int 1181 vnodetopath_common(vnode_t *vrootp, vnode_t *vp, char *buf, size_t buflen, 1182 cred_t *cr, int flags) 1183 { 1184 pathname_t pn, rpn; 1185 int ret, len; 1186 vnode_t *compvp, *pvp, *realvp; 1187 proc_t *p = curproc; 1188 char path[MAXNAMELEN]; 1189 int doclose = 0; 1190 1191 /* 1192 * If vrootp is NULL, get the root for curproc. Callers with any other 1193 * requirements should pass in a different vrootp. 1194 */ 1195 if (vrootp == NULL) { 1196 mutex_enter(&p->p_lock); 1197 if ((vrootp = PTOU(p)->u_rdir) == NULL) 1198 vrootp = rootdir; 1199 VN_HOLD(vrootp); 1200 mutex_exit(&p->p_lock); 1201 } else { 1202 VN_HOLD(vrootp); 1203 } 1204 1205 /* 1206 * This is to get around an annoying artifact of the /proc filesystem, 1207 * which is the behavior of {cwd/root}. Trying to resolve this path 1208 * will result in /proc/pid/cwd instead of whatever the real working 1209 * directory is. We can't rely on VOP_REALVP(), since that will break 1210 * lofs. The only difference between procfs and lofs is that opening 1211 * the file will return the underling vnode in the case of procfs. 1212 */ 1213 if (vp->v_type == VDIR && VOP_REALVP(vp, &realvp) == 0 && 1214 realvp != vp) { 1215 VN_HOLD(vp); 1216 if (VOP_OPEN(&vp, FREAD, cr) == 0) 1217 doclose = 1; 1218 else 1219 VN_RELE(vp); 1220 } 1221 1222 pn_alloc(&pn); 1223 1224 /* 1225 * Check to see if we have a cached path in the vnode. 1226 */ 1227 mutex_enter(&vp->v_lock); 1228 if (vp->v_path != NULL) { 1229 (void) pn_set(&pn, vp->v_path); 1230 mutex_exit(&vp->v_lock); 1231 1232 pn_alloc(&rpn); 1233 1234 /* We should only cache absolute paths */ 1235 ASSERT(pn.pn_buf[0] == '/'); 1236 1237 /* 1238 * If we are in a zone or a chroot environment, then we have to 1239 * take additional steps, since the path to the root might not 1240 * be readable with the current credentials, even though the 1241 * process can legitmately access the file. In this case, we 1242 * do the following: 1243 * 1244 * lookuppnvp() with all privileges to get the resolved path. 1245 * call localpath() to get the local portion of the path, and 1246 * continue as normal. 1247 * 1248 * If the the conversion to a local path fails, then we continue 1249 * as normal. This is a heuristic to make process object file 1250 * paths available from within a zone. Because lofs doesn't 1251 * support page operations, the vnode stored in the seg_t is 1252 * actually the underlying real vnode, not the lofs node itself. 1253 * Most of the time, the lofs path is the same as the underlying 1254 * vnode (for example, /usr/lib/libc.so.1). 1255 */ 1256 if (vrootp != rootdir) { 1257 char *local = NULL; 1258 VN_HOLD(rootdir); 1259 if (lookuppnvp(&pn, &rpn, FOLLOW, 1260 NULL, &compvp, rootdir, rootdir, kcred) == 0) { 1261 local = localpath(rpn.pn_path, vrootp, 1262 kcred); 1263 VN_RELE(compvp); 1264 } 1265 1266 /* 1267 * The original pn was changed through lookuppnvp(), so 1268 * reset it. 1269 */ 1270 if (local) { 1271 (void) pn_set(&pn, local); 1272 } else { 1273 mutex_enter(&vp->v_lock); 1274 if (vp->v_path != NULL) { 1275 (void) pn_set(&pn, vp->v_path); 1276 mutex_exit(&vp->v_lock); 1277 } else { 1278 mutex_exit(&vp->v_lock); 1279 goto notcached; 1280 } 1281 } 1282 } 1283 1284 /* 1285 * We should have a local path at this point, so start the 1286 * search from the root of the current process. 1287 */ 1288 VN_HOLD(vrootp); 1289 if (vrootp != rootdir) 1290 VN_HOLD(vrootp); 1291 ret = lookuppnvp(&pn, &rpn, FOLLOW | flags, NULL, 1292 &compvp, vrootp, vrootp, cr); 1293 if (ret == 0) { 1294 /* 1295 * Check to see if the returned vnode is the same as 1296 * the one we expect. If not, give up. 1297 */ 1298 if (!vn_compare(vp, compvp) && 1299 !vnode_match(vp, compvp, cr)) { 1300 VN_RELE(compvp); 1301 goto notcached; 1302 } 1303 1304 VN_RELE(compvp); 1305 1306 /* 1307 * Return the result. 1308 */ 1309 if (buflen <= rpn.pn_pathlen) 1310 goto notcached; 1311 1312 bcopy(rpn.pn_path, buf, rpn.pn_pathlen + 1); 1313 pn_free(&pn); 1314 pn_free(&rpn); 1315 VN_RELE(vrootp); 1316 if (doclose) { 1317 (void) VOP_CLOSE(vp, FREAD, 1, 0, cr); 1318 VN_RELE(vp); 1319 } 1320 return (0); 1321 } 1322 1323 notcached: 1324 pn_free(&rpn); 1325 } else { 1326 mutex_exit(&vp->v_lock); 1327 } 1328 1329 pn_free(&pn); 1330 1331 if (vp->v_type != VDIR) { 1332 /* 1333 * If we don't have a directory, try to find it in the dnlc via 1334 * reverse lookup. Once this is found, we can use the regular 1335 * directory search to find the full path. 1336 */ 1337 if ((pvp = dnlc_reverse_lookup(vp, path, MAXNAMELEN)) != NULL) { 1338 ret = dirtopath(vrootp, pvp, buf, buflen, cr); 1339 if (ret == 0) { 1340 len = strlen(buf); 1341 if (len + strlen(path) + 1 >= buflen) { 1342 ret = ENAMETOOLONG; 1343 } else { 1344 if (buf[len - 1] != '/') 1345 buf[len++] = '/'; 1346 bcopy(path, buf + len, 1347 strlen(path) + 1); 1348 } 1349 } 1350 1351 VN_RELE(pvp); 1352 } else 1353 ret = ENOENT; 1354 } else 1355 ret = dirtopath(vrootp, vp, buf, buflen, cr); 1356 1357 VN_RELE(vrootp); 1358 if (doclose) { 1359 (void) VOP_CLOSE(vp, FREAD, 1, 0, cr); 1360 VN_RELE(vp); 1361 } 1362 1363 return (ret); 1364 } 1365 1366 int 1367 vnodetopath(vnode_t *vrootp, vnode_t *vp, char *buf, size_t buflen, cred_t *cr) 1368 { 1369 return (vnodetopath_common(vrootp, vp, buf, buflen, cr, 0)); 1370 } 1371 1372 int 1373 dogetcwd(char *buf, size_t buflen) 1374 { 1375 int ret; 1376 vnode_t *vp; 1377 vnode_t *compvp; 1378 refstr_t *cwd, *oldcwd; 1379 const char *value; 1380 pathname_t rpnp, pnp; 1381 proc_t *p = curproc; 1382 1383 /* 1384 * Check to see if there is a cached version of the cwd. If so, lookup 1385 * the cached value and make sure it is the same vnode. 1386 */ 1387 mutex_enter(&p->p_lock); 1388 if ((cwd = PTOU(p)->u_cwd) != NULL) 1389 refstr_hold(cwd); 1390 vp = PTOU(p)->u_cdir; 1391 VN_HOLD(vp); 1392 mutex_exit(&p->p_lock); 1393 1394 /* 1395 * Make sure we have permission to access the current directory. 1396 */ 1397 if ((ret = VOP_ACCESS(vp, VEXEC, 0, CRED())) != 0) { 1398 if (cwd != NULL) 1399 refstr_rele(cwd); 1400 VN_RELE(vp); 1401 return (ret); 1402 } 1403 1404 if (cwd) { 1405 value = refstr_value(cwd); 1406 if ((ret = pn_get((char *)value, UIO_SYSSPACE, &pnp)) != 0) { 1407 refstr_rele(cwd); 1408 VN_RELE(vp); 1409 return (ret); 1410 } 1411 1412 pn_alloc(&rpnp); 1413 1414 if (lookuppn(&pnp, &rpnp, NO_FOLLOW, NULL, &compvp) == 0) { 1415 1416 if (VN_CMP(vp, compvp) && 1417 strcmp(value, rpnp.pn_path) == 0) { 1418 VN_RELE(compvp); 1419 VN_RELE(vp); 1420 pn_free(&pnp); 1421 pn_free(&rpnp); 1422 if (strlen(value) + 1 > buflen) { 1423 refstr_rele(cwd); 1424 return (ENAMETOOLONG); 1425 } 1426 bcopy(value, buf, strlen(value) + 1); 1427 refstr_rele(cwd); 1428 return (0); 1429 } 1430 1431 VN_RELE(compvp); 1432 } 1433 1434 pn_free(&rpnp); 1435 pn_free(&pnp); 1436 1437 refstr_rele(cwd); 1438 } 1439 1440 ret = vnodetopath_common(NULL, vp, buf, buflen, CRED(), 1441 LOOKUP_CHECKREAD); 1442 1443 VN_RELE(vp); 1444 1445 /* 1446 * Store the new cwd and replace the existing cached copy. 1447 */ 1448 if (ret == 0) 1449 cwd = refstr_alloc(buf); 1450 else 1451 cwd = NULL; 1452 1453 mutex_enter(&p->p_lock); 1454 oldcwd = PTOU(p)->u_cwd; 1455 PTOU(p)->u_cwd = cwd; 1456 mutex_exit(&p->p_lock); 1457 1458 if (oldcwd) 1459 refstr_rele(oldcwd); 1460 1461 return (ret); 1462 } 1463