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 2016 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 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 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 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 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 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 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 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 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 * 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 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 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 uio.uio_iov = &iov; 831 uio.uio_iovcnt = 1; 832 uio.uio_segflg = UIO_SYSSPACE; 833 uio.uio_fmode = 0; 834 uio.uio_extflg = UIO_COPY_CACHED; 835 uio.uio_loffset = 0; 836 837 if ((error = VOP_ACCESS(dvp, VREAD, 0, cr, NULL)) != 0) 838 return (error); 839 840 dp = NULL; 841 eof = 0; 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 * Clean a stale v_path from a vnode. This is only performed if the v_path has 983 * not been altered since it was found to be stale 984 */ 985 static void 986 vnode_clear_vpath(vnode_t *vp, char *vpath_old) 987 { 988 mutex_enter(&vp->v_lock); 989 if (vp->v_path != vn_vpath_empty && vp->v_path == vpath_old) { 990 vp->v_path = vn_vpath_empty; 991 mutex_exit(&vp->v_lock); 992 kmem_free(vpath_old, strlen(vpath_old) + 1); 993 } else { 994 mutex_exit(&vp->v_lock); 995 } 996 } 997 998 /* 999 * Validate that a pathname refers to a given vnode. 1000 */ 1001 static int 1002 vnode_valid_pn(vnode_t *vp, vnode_t *vrootp, pathname_t *pn, pathname_t *rpn, 1003 int flags, cred_t *cr) 1004 { 1005 vnode_t *compvp; 1006 /* 1007 * If we are in a zone or a chroot environment, then we have to 1008 * take additional steps, since the path to the root might not 1009 * be readable with the current credentials, even though the 1010 * process can legitmately access the file. In this case, we 1011 * do the following: 1012 * 1013 * lookuppnvp() with all privileges to get the resolved path. 1014 * call localpath() to get the local portion of the path, and 1015 * continue as normal. 1016 * 1017 * If the the conversion to a local path fails, then we continue 1018 * as normal. This is a heuristic to make process object file 1019 * paths available from within a zone. Because lofs doesn't 1020 * support page operations, the vnode stored in the seg_t is 1021 * actually the underlying real vnode, not the lofs node itself. 1022 * Most of the time, the lofs path is the same as the underlying 1023 * vnode (for example, /usr/lib/libc.so.1). 1024 */ 1025 if (vrootp != rootdir) { 1026 char *local = NULL; 1027 1028 VN_HOLD(rootdir); 1029 if (lookuppnvp(pn, rpn, FOLLOW, NULL, &compvp, rootdir, 1030 rootdir, kcred) == 0) { 1031 local = localpath(rpn->pn_path, vrootp, kcred); 1032 VN_RELE(compvp); 1033 } 1034 1035 /* 1036 * The original pn was changed through lookuppnvp(). 1037 * Set it to local for next validation attempt. 1038 */ 1039 if (local) { 1040 (void) pn_set(pn, local); 1041 } else { 1042 return (1); 1043 } 1044 } 1045 1046 /* 1047 * We should have a local path at this point, so start the search from 1048 * the root of the current process. 1049 */ 1050 VN_HOLD(vrootp); 1051 if (vrootp != rootdir) 1052 VN_HOLD(vrootp); 1053 if (lookuppnvp(pn, rpn, FOLLOW | flags, NULL, &compvp, vrootp, vrootp, 1054 cr) == 0) { 1055 /* 1056 * Check to see if the returned vnode is the same as the one we 1057 * expect. 1058 */ 1059 if (vn_compare(vp, compvp) || 1060 vnode_match(vp, compvp, cr)) { 1061 VN_RELE(compvp); 1062 return (0); 1063 } else { 1064 VN_RELE(compvp); 1065 } 1066 } 1067 1068 return (1); 1069 } 1070 1071 /* 1072 * Struct for tracking vnodes with invalidated v_path entries during a 1073 * dirtopath reverse lookup. By keeping adequate state, those vnodes can be 1074 * revisted to populate v_path. 1075 */ 1076 struct dirpath_walk { 1077 struct dirpath_walk *dw_next; 1078 vnode_t *dw_vnode; 1079 vnode_t *dw_pvnode; 1080 size_t dw_len; 1081 char *dw_name; 1082 }; 1083 1084 /* 1085 * Given a directory, return the full, resolved path. This looks up "..", 1086 * searches for the given vnode in the parent, appends the component, etc. It 1087 * is used to implement vnodetopath() and getcwd() when the cached path fails. 1088 */ 1089 static int 1090 dirtopath(vnode_t *vrootp, vnode_t *vp, char *buf, size_t buflen, int flags, 1091 cred_t *cr) 1092 { 1093 pathname_t pn, rpn, emptypn; 1094 vnode_t *pvp = NULL, *startvp = vp; 1095 int err = 0; 1096 size_t complen; 1097 dirent64_t *dp; 1098 char *bufloc, *dbuf; 1099 const size_t dlen = DIRENT64_RECLEN(MAXPATHLEN); 1100 struct dirpath_walk *dw_chain = NULL, *dw_entry; 1101 1102 /* Operation only allowed on directories */ 1103 ASSERT(vp->v_type == VDIR); 1104 1105 /* We must have at least enough space for "/" */ 1106 if (buflen < 2) 1107 return (ENAMETOOLONG); 1108 1109 /* Start at end of string with terminating null */ 1110 bufloc = &buf[buflen - 1]; 1111 *bufloc = '\0'; 1112 1113 pn_alloc(&pn); 1114 pn_alloc(&rpn); 1115 dbuf = kmem_alloc(dlen, KM_SLEEP); 1116 bzero(&emptypn, sizeof (emptypn)); 1117 1118 /* 1119 * Begin with an additional reference on vp. This will be decremented 1120 * during the loop. 1121 */ 1122 VN_HOLD(vp); 1123 1124 for (;;) { 1125 int vprivs; 1126 hrtime_t cached_stamp; 1127 1128 /* 1129 * Return if we've reached the root. If the buffer is empty, 1130 * return '/'. We explicitly don't use vn_compare(), since it 1131 * compares the real vnodes. A lofs mount of '/' would produce 1132 * incorrect results otherwise. 1133 */ 1134 if (VN_CMP(vrootp, vp)) { 1135 if (*bufloc == '\0') 1136 *--bufloc = '/'; 1137 break; 1138 } 1139 1140 /* 1141 * If we've reached the VFS root, something has gone wrong. We 1142 * should have reached the root in the above check. The only 1143 * explantation is that 'vp' is not contained withing the given 1144 * root, in which case we return EPERM. 1145 */ 1146 if (VN_CMP(rootdir, vp)) { 1147 err = EPERM; 1148 goto out; 1149 } 1150 1151 /* 1152 * Shortcut: see if this vnode has correct v_path. If so, 1153 * we have the work done. 1154 */ 1155 mutex_enter(&vp->v_lock); 1156 if (vp->v_path != vn_vpath_empty && 1157 pn_set(&pn, vp->v_path) == 0) { 1158 cached_stamp = vp->v_path_stamp; 1159 mutex_exit(&vp->v_lock); 1160 rpn.pn_path = rpn.pn_buf; 1161 1162 /* Ensure the v_path pointing to correct vnode */ 1163 if (vnode_valid_pn(vp, vrootp, &pn, &rpn, flags, 1164 cr) == 0) { 1165 complen = strlen(rpn.pn_path); 1166 bufloc -= complen; 1167 if (bufloc < buf) { 1168 err = ERANGE; 1169 goto out; 1170 } 1171 bcopy(rpn.pn_path, bufloc, complen); 1172 break; 1173 } else { 1174 /* 1175 * Immediately nuke cached v_path entries known 1176 * to be invalid. 1177 */ 1178 vn_clearpath(vp, cached_stamp); 1179 } 1180 } else { 1181 mutex_exit(&vp->v_lock); 1182 } 1183 1184 /* 1185 * Shortcuts failed, search for this vnode in its parent. If 1186 * this is a mountpoint, then get the vnode underneath. 1187 */ 1188 if (vp->v_flag & VROOT) 1189 vp = vn_under(vp); 1190 if ((err = VOP_LOOKUP(vp, "..", &pvp, &emptypn, 0, vrootp, cr, 1191 NULL, NULL, NULL)) != 0) 1192 goto out; 1193 1194 /* 1195 * With extended attributes, it's possible for a directory to 1196 * have a parent that is a regular file. Check for that here. 1197 */ 1198 if (pvp->v_type != VDIR) { 1199 err = ENOTDIR; 1200 goto out; 1201 } 1202 1203 /* 1204 * If this is true, something strange has happened. This is 1205 * only true if we are the root of a filesystem, which should 1206 * have been caught by the check above. 1207 */ 1208 if (VN_CMP(pvp, vp)) { 1209 err = ENOENT; 1210 goto out; 1211 } 1212 1213 /* 1214 * Check if we have read and search privilege so, that 1215 * we can lookup the path in the directory 1216 */ 1217 vprivs = (flags & LOOKUP_CHECKREAD) ? VREAD | VEXEC : VEXEC; 1218 if ((err = VOP_ACCESS(pvp, vprivs, 0, cr, NULL)) != 0) { 1219 goto out; 1220 } 1221 1222 /* 1223 * Search the parent directory for the entry corresponding to 1224 * this vnode. 1225 */ 1226 if ((err = dirfindvp(vrootp, pvp, vp, cr, dbuf, dlen, &dp)) 1227 != 0) 1228 goto out; 1229 complen = strlen(dp->d_name); 1230 bufloc -= complen; 1231 if (bufloc <= buf) { 1232 err = ENAMETOOLONG; 1233 goto out; 1234 } 1235 bcopy(dp->d_name, bufloc, complen); 1236 1237 /* Prepend a slash to the current path. */ 1238 *--bufloc = '/'; 1239 1240 /* 1241 * Record the name and directory for later reconstruction and 1242 * link it up with the others. 1243 */ 1244 dw_entry = kmem_alloc(sizeof (*dw_entry), KM_SLEEP); 1245 dw_entry->dw_name = kmem_alloc(complen + 1, KM_SLEEP); 1246 VN_HOLD(dw_entry->dw_vnode = vp); 1247 VN_HOLD(dw_entry->dw_pvnode = pvp); 1248 bcopy(dp->d_name, dw_entry->dw_name, complen + 1); 1249 dw_entry->dw_len = complen; 1250 dw_entry->dw_next = dw_chain; 1251 dw_chain = dw_entry; 1252 1253 /* And continue with the next component */ 1254 VN_RELE(vp); 1255 vp = pvp; 1256 pvp = NULL; 1257 } 1258 1259 /* 1260 * Place the path at the beginning of the buffer. 1261 */ 1262 if (bufloc != buf) 1263 ovbcopy(bufloc, buf, buflen - (bufloc - buf)); 1264 1265 out: 1266 /* 1267 * Walk over encountered directory entries which were afflicted with a 1268 * stale or absent v_path. If the dirtopath was successful, we should 1269 * possess the necessary information to populate all of them with a 1270 * valid v_path. 1271 * 1272 * While processing this list, it is safe to call vn_setpath despite 1273 * the fact that racing vnode actions may have altered v_path entries 1274 * while the above loopwas still executing. Any updated entries will 1275 * have a newer v_path_stamp value which prevents an invalid overwrite. 1276 * 1277 * If an error was encountered during the search, freeing the chain is 1278 * still required. 1279 */ 1280 dw_entry = dw_chain; 1281 while (dw_entry != NULL) { 1282 struct dirpath_walk *next = dw_entry->dw_next; 1283 1284 if (err == 0) { 1285 vn_setpath(NULL, dw_entry->dw_pvnode, 1286 dw_entry->dw_vnode, dw_entry->dw_name, 1287 dw_entry->dw_len); 1288 } 1289 1290 VN_RELE(dw_entry->dw_vnode); 1291 VN_RELE(dw_entry->dw_pvnode); 1292 kmem_free(dw_entry->dw_name, dw_entry->dw_len + 1); 1293 kmem_free(dw_entry, sizeof (*dw_entry)); 1294 dw_entry = next; 1295 } 1296 1297 /* 1298 * If the error was ESTALE and the current directory to look in 1299 * was the root for this lookup, the root for a mounted file 1300 * system, or the starting directory for lookups, then 1301 * return ENOENT instead of ESTALE. In this case, no recovery 1302 * is possible by the higher level. If ESTALE was returned for 1303 * some intermediate directory along the path, then recovery 1304 * is potentially possible and retrying from the higher level 1305 * will either correct the situation by purging stale cache 1306 * entries or eventually get back to the point where no recovery 1307 * is possible. 1308 */ 1309 if (err == ESTALE && 1310 (VN_CMP(vp, vrootp) || (vp->v_flag & VROOT) || vp == startvp)) 1311 err = ENOENT; 1312 1313 kmem_free(dbuf, dlen); 1314 VN_RELE(vp); 1315 if (pvp) 1316 VN_RELE(pvp); 1317 pn_free(&pn); 1318 pn_free(&rpn); 1319 1320 return (err); 1321 } 1322 1323 /* 1324 * The additional flag, LOOKUP_CHECKREAD, is used to enforce artificial 1325 * constraints in order to be standards compliant. For example, if we have 1326 * the cached path of '/foo/bar', and '/foo' has permissions 100 (execute 1327 * only), then we can legitimately look up the path to the current working 1328 * directory without needing read permission. Existing standards tests, 1329 * however, assume that we are determining the path by repeatedly looking up 1330 * "..". We need to keep this behavior in order to maintain backwards 1331 * compatibility. 1332 */ 1333 static int 1334 vnodetopath_common(vnode_t *vrootp, vnode_t *vp, char *buf, size_t buflen, 1335 cred_t *cr, int flags) 1336 { 1337 pathname_t pn; 1338 int ret = 0; 1339 vnode_t *realvp; 1340 boolean_t doclose = B_FALSE; 1341 1342 /* 1343 * If vrootp is NULL, get the root for curproc. Callers with any other 1344 * requirements should pass in a different vrootp. 1345 */ 1346 if (vrootp == NULL) { 1347 proc_t *p = curproc; 1348 1349 mutex_enter(&p->p_lock); 1350 if ((vrootp = PTOU(p)->u_rdir) == NULL) 1351 vrootp = rootdir; 1352 VN_HOLD(vrootp); 1353 mutex_exit(&p->p_lock); 1354 } else { 1355 VN_HOLD(vrootp); 1356 } 1357 1358 /* 1359 * This is to get around an annoying artifact of the /proc filesystem, 1360 * which is the behavior of {cwd/root}. Trying to resolve this path 1361 * will result in /proc/pid/cwd instead of whatever the real working 1362 * directory is. We can't rely on VOP_REALVP(), since that will break 1363 * lofs. The only difference between procfs and lofs is that opening 1364 * the file will return the underling vnode in the case of procfs. 1365 */ 1366 if (vp->v_type == VDIR && VOP_REALVP(vp, &realvp, NULL) == 0 && 1367 realvp != vp) { 1368 VN_HOLD(vp); 1369 if (VOP_OPEN(&vp, FREAD, cr, NULL) == 0) 1370 doclose = B_TRUE; 1371 else 1372 VN_RELE(vp); 1373 } 1374 1375 /* 1376 * Check to see if we have a valid cached path in the vnode. 1377 */ 1378 pn_alloc(&pn); 1379 mutex_enter(&vp->v_lock); 1380 if (vp->v_path != vn_vpath_empty) { 1381 hrtime_t cached_stamp; 1382 pathname_t rpn; 1383 1384 cached_stamp = vp->v_path_stamp; 1385 (void) pn_set(&pn, vp->v_path); 1386 mutex_exit(&vp->v_lock); 1387 1388 /* We should only cache absolute paths */ 1389 ASSERT(pn.pn_buf[0] == '/'); 1390 1391 pn_alloc(&rpn); 1392 if (vnode_valid_pn(vp, vrootp, &pn, &rpn, flags, cr) == 0) { 1393 /* Return the result, if we're able. */ 1394 if (buflen > rpn.pn_pathlen) { 1395 bcopy(rpn.pn_path, buf, rpn.pn_pathlen + 1); 1396 } else { 1397 ret = ENAMETOOLONG; 1398 } 1399 pn_free(&pn); 1400 pn_free(&rpn); 1401 goto out; 1402 } 1403 pn_free(&rpn); 1404 vn_clearpath(vp, cached_stamp); 1405 } else { 1406 mutex_exit(&vp->v_lock); 1407 } 1408 pn_free(&pn); 1409 1410 if (vp->v_type != VDIR) { 1411 /* 1412 * The reverse lookup tricks used by dirtopath aren't possible 1413 * for non-directory entries. The best which can be done is 1414 * clearing any stale v_path so later lookups can potentially 1415 * repopulate it with a valid path. 1416 */ 1417 ret = ENOENT; 1418 } else { 1419 ret = dirtopath(vrootp, vp, buf, buflen, flags, cr); 1420 } 1421 1422 out: 1423 VN_RELE(vrootp); 1424 if (doclose) { 1425 (void) VOP_CLOSE(vp, FREAD, 1, 0, cr, NULL); 1426 VN_RELE(vp); 1427 } 1428 1429 return (ret); 1430 } 1431 1432 int 1433 vnodetopath(vnode_t *vrootp, vnode_t *vp, char *buf, size_t buflen, cred_t *cr) 1434 { 1435 return (vnodetopath_common(vrootp, vp, buf, buflen, cr, 0)); 1436 } 1437 1438 int 1439 dogetcwd(char *buf, size_t buflen) 1440 { 1441 int ret; 1442 vnode_t *vp; 1443 vnode_t *compvp; 1444 refstr_t *cwd, *oldcwd; 1445 const char *value; 1446 pathname_t rpnp, pnp; 1447 proc_t *p = curproc; 1448 1449 /* 1450 * Check to see if there is a cached version of the cwd. If so, lookup 1451 * the cached value and make sure it is the same vnode. 1452 */ 1453 mutex_enter(&p->p_lock); 1454 if ((cwd = PTOU(p)->u_cwd) != NULL) 1455 refstr_hold(cwd); 1456 vp = PTOU(p)->u_cdir; 1457 VN_HOLD(vp); 1458 mutex_exit(&p->p_lock); 1459 1460 /* 1461 * Make sure we have permission to access the current directory. 1462 */ 1463 if ((ret = VOP_ACCESS(vp, VEXEC, 0, CRED(), NULL)) != 0) { 1464 if (cwd != NULL) 1465 refstr_rele(cwd); 1466 VN_RELE(vp); 1467 return (ret); 1468 } 1469 1470 if (cwd) { 1471 value = refstr_value(cwd); 1472 if ((ret = pn_get((char *)value, UIO_SYSSPACE, &pnp)) != 0) { 1473 refstr_rele(cwd); 1474 VN_RELE(vp); 1475 return (ret); 1476 } 1477 1478 pn_alloc(&rpnp); 1479 1480 if (lookuppn(&pnp, &rpnp, NO_FOLLOW, NULL, &compvp) == 0) { 1481 1482 if (VN_CMP(vp, compvp) && 1483 strcmp(value, rpnp.pn_path) == 0) { 1484 VN_RELE(compvp); 1485 VN_RELE(vp); 1486 pn_free(&pnp); 1487 pn_free(&rpnp); 1488 if (strlen(value) + 1 > buflen) { 1489 refstr_rele(cwd); 1490 return (ENAMETOOLONG); 1491 } 1492 bcopy(value, buf, strlen(value) + 1); 1493 refstr_rele(cwd); 1494 return (0); 1495 } 1496 1497 VN_RELE(compvp); 1498 } 1499 1500 pn_free(&rpnp); 1501 pn_free(&pnp); 1502 1503 refstr_rele(cwd); 1504 } 1505 1506 ret = vnodetopath_common(NULL, vp, buf, buflen, CRED(), 1507 LOOKUP_CHECKREAD); 1508 1509 VN_RELE(vp); 1510 1511 /* 1512 * Store the new cwd and replace the existing cached copy. 1513 */ 1514 if (ret == 0) 1515 cwd = refstr_alloc(buf); 1516 else 1517 cwd = NULL; 1518 1519 mutex_enter(&p->p_lock); 1520 oldcwd = PTOU(p)->u_cwd; 1521 PTOU(p)->u_cwd = cwd; 1522 mutex_exit(&p->p_lock); 1523 1524 if (oldcwd) 1525 refstr_rele(oldcwd); 1526 1527 return (ret); 1528 } 1529