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 2009 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 #include <sys/types.h> 40 #include <sys/param.h> 41 #include <sys/systm.h> 42 #include <sys/cpuvar.h> 43 #include <sys/errno.h> 44 #include <sys/cred.h> 45 #include <sys/user.h> 46 #include <sys/uio.h> 47 #include <sys/vfs.h> 48 #include <sys/vnode.h> 49 #include <sys/pathname.h> 50 #include <sys/proc.h> 51 #include <sys/vtrace.h> 52 #include <sys/sysmacros.h> 53 #include <sys/debug.h> 54 #include <sys/dirent.h> 55 #include <c2/audit.h> 56 #include <sys/zone.h> 57 #include <sys/dnlc.h> 58 #include <sys/fs/snode.h> 59 60 /* Controls whether paths are stored with vnodes. */ 61 int vfs_vnode_path = 1; 62 63 int 64 lookupname( 65 char *fnamep, 66 enum uio_seg seg, 67 enum symfollow followlink, 68 vnode_t **dirvpp, 69 vnode_t **compvpp) 70 { 71 return (lookupnameatcred(fnamep, seg, followlink, dirvpp, compvpp, NULL, 72 CRED())); 73 } 74 75 /* 76 * Lookup the user file name, 77 * Handle allocation and freeing of pathname buffer, return error. 78 */ 79 int 80 lookupnameatcred( 81 char *fnamep, /* user pathname */ 82 enum uio_seg seg, /* addr space that name is in */ 83 enum symfollow followlink, /* follow sym links */ 84 vnode_t **dirvpp, /* ret for ptr to parent dir vnode */ 85 vnode_t **compvpp, /* ret for ptr to component vnode */ 86 vnode_t *startvp, /* start path search from vp */ 87 cred_t *cr) /* credential */ 88 { 89 char namebuf[TYPICALMAXPATHLEN]; 90 struct pathname lookpn; 91 int error; 92 93 error = pn_get_buf(fnamep, seg, &lookpn, namebuf, sizeof (namebuf)); 94 if (error == 0) { 95 if (audit_active) 96 audit_lookupname(); 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, enum symfollow 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 enum symfollow 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 enum symfollow 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 enum symfollow 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 vnode_t *tvp; /* addressable temp ptr */ 223 char component[MAXNAMELEN]; /* buffer for component (incl null) */ 224 int error; 225 int nlink; 226 int lookup_flags; 227 struct pathname presrvd; /* case preserved name */ 228 struct pathname *pp = NULL; 229 vnode_t *startvp; 230 vnode_t *zonevp = curproc->p_zone->zone_rootvp; /* zone root */ 231 int must_be_directory = 0; 232 boolean_t retry_with_kcred; 233 234 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 (audit_active) 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 if (audit_active) 280 audit_addcomponent(pnp); 281 goto bad; 282 } 283 284 /* 285 * Handle "..": two special cases. 286 * 1. If we're at the root directory (e.g. after chroot or 287 * zone_enter) then change ".." to "." so we can't get 288 * out of this subtree. 289 * 2. If this vnode is the root of a mounted file system, 290 * then replace it with the vnode that was mounted on 291 * so that we take the ".." in the other file system. 292 */ 293 if (component[0] == '.' && component[1] == '.' && component[2] == 0) { 294 checkforroot: 295 if (VN_CMP(vp, rootvp) || VN_CMP(vp, zonevp)) { 296 component[1] = '\0'; 297 } else if (vp->v_flag & VROOT) { 298 vfs_t *vfsp; 299 cvp = vp; 300 301 /* 302 * While we deal with the vfs pointer from the vnode 303 * the filesystem could have been forcefully unmounted 304 * and the vnode's v_vfsp could have been invalidated 305 * by VFS_UNMOUNT. Hence, we cache v_vfsp and use it 306 * with vfs_rlock_wait/vfs_unlock. 307 * It is safe to use the v_vfsp even it is freed by 308 * VFS_UNMOUNT because vfs_rlock_wait/vfs_unlock 309 * do not dereference v_vfsp. It is just used as a 310 * magic cookie. 311 * One more corner case here is the memory getting 312 * reused for another vfs structure. In this case 313 * lookuppnvp's vfs_rlock_wait will succeed, domount's 314 * vfs_lock will fail and domount will bail out with an 315 * error (EBUSY). 316 */ 317 vfsp = cvp->v_vfsp; 318 319 /* 320 * This lock is used to synchronize 321 * mounts/unmounts and lookups. 322 * Threads doing mounts/unmounts hold the 323 * writers version vfs_lock_wait(). 324 */ 325 326 vfs_rlock_wait(vfsp); 327 328 /* 329 * If this vnode is on a file system that 330 * has been forcibly unmounted, 331 * we can't proceed. Cancel this operation 332 * and return EIO. 333 * 334 * vfs_vnodecovered is NULL if unmounted. 335 * Currently, nfs uses VFS_UNMOUNTED to 336 * check if it's a forced-umount. Keep the 337 * same checking here as well even though it 338 * may not be needed. 339 */ 340 if (((vp = cvp->v_vfsp->vfs_vnodecovered) == NULL) || 341 (cvp->v_vfsp->vfs_flag & VFS_UNMOUNTED)) { 342 vfs_unlock(vfsp); 343 VN_RELE(cvp); 344 if (pp) 345 pn_free(pp); 346 return (EIO); 347 } 348 VN_HOLD(vp); 349 vfs_unlock(vfsp); 350 VN_RELE(cvp); 351 cvp = NULL; 352 /* 353 * Crossing mount points. For eg: We are doing 354 * a lookup of ".." for file systems root vnode 355 * mounted here, and VOP_LOOKUP() (with covered vnode) 356 * will be on underlying file systems mount point 357 * vnode. Set retry_with_kcred flag as we might end 358 * up doing VOP_LOOKUP() with kcred if required. 359 */ 360 retry_with_kcred = B_TRUE; 361 goto checkforroot; 362 } 363 } 364 365 /* 366 * LOOKUP_CHECKREAD is a private flag used by vnodetopath() to indicate 367 * that we need to have read permission on every directory in the entire 368 * path. This is used to ensure that a forward-lookup of a cached value 369 * has the same effect as a reverse-lookup when the cached value cannot 370 * be found. 371 */ 372 if ((flags & LOOKUP_CHECKREAD) && 373 (error = VOP_ACCESS(vp, VREAD, 0, cr, NULL)) != 0) 374 goto bad; 375 376 /* 377 * Perform a lookup in the current directory. 378 */ 379 error = VOP_LOOKUP(vp, component, &tvp, pnp, lookup_flags, 380 rootvp, cr, NULL, NULL, pp); 381 382 /* 383 * Retry with kcred - If crossing mount points & error is EACCES. 384 * 385 * If we are crossing mount points here and doing ".." lookup, 386 * VOP_LOOKUP() might fail if the underlying file systems 387 * mount point has no execute permission. In cases like these, 388 * we retry VOP_LOOKUP() by giving as much privilage as possible 389 * by passing kcred credentials. 390 * 391 * In case of hierarchical file systems, passing kcred still may 392 * or may not work. 393 * For eg: UFS FS --> Mount NFS FS --> Again mount UFS on some 394 * directory inside NFS FS. 395 */ 396 if ((error == EACCES) && retry_with_kcred) 397 error = VOP_LOOKUP(vp, component, &tvp, pnp, lookup_flags, 398 rootvp, zone_kcred(), NULL, NULL, pp); 399 400 cvp = tvp; 401 if (error) { 402 cvp = NULL; 403 /* 404 * On error, return hard error if 405 * (a) we're not at the end of the pathname yet, or 406 * (b) the caller didn't want the parent directory, or 407 * (c) we failed for some reason other than a missing entry. 408 */ 409 if (pn_pathleft(pnp) || dirvpp == NULL || error != ENOENT) 410 goto bad; 411 if (audit_active) { /* directory access */ 412 if (error = audit_savepath(pnp, vp, error, cr)) 413 goto bad_noaudit; 414 } 415 pn_setlast(pnp); 416 /* 417 * We inform the caller that the desired entry must be 418 * a directory by adding a '/' to the component name. 419 */ 420 if (must_be_directory && (error = pn_addslash(pnp)) != 0) 421 goto bad; 422 *dirvpp = vp; 423 if (compvpp != NULL) 424 *compvpp = NULL; 425 if (rootvp != rootdir) 426 VN_RELE(rootvp); 427 if (pp) 428 pn_free(pp); 429 return (0); 430 } 431 432 /* 433 * Traverse mount points. 434 * XXX why don't we need to hold a read lock here (call vn_vfsrlock)? 435 * What prevents a concurrent update to v_vfsmountedhere? 436 * Possible answer: if mounting, we might not see the mount 437 * if it is concurrently coming into existence, but that's 438 * really not much different from the thread running a bit slower. 439 * If unmounting, we may get into traverse() when we shouldn't, 440 * but traverse() will catch this case for us. 441 * (For this to work, fetching v_vfsmountedhere had better 442 * be atomic!) 443 */ 444 if (vn_mountedvfs(cvp) != NULL) { 445 tvp = cvp; 446 if ((error = traverse(&tvp)) != 0) { 447 /* 448 * It is required to assign cvp here, because 449 * traverse() will return a held vnode which 450 * may different than the vnode that was passed 451 * in (even in the error case). If traverse() 452 * changes the vnode it releases the original, 453 * and holds the new one. 454 */ 455 cvp = tvp; 456 goto bad; 457 } 458 cvp = tvp; 459 } 460 461 /* 462 * If we hit a symbolic link and there is more path to be 463 * translated or this operation does not wish to apply 464 * to a link, then place the contents of the link at the 465 * front of the remaining pathname. 466 */ 467 if (cvp->v_type == VLNK && ((flags & FOLLOW) || pn_pathleft(pnp))) { 468 struct pathname linkpath; 469 if (audit_active) { 470 if (error = audit_pathcomp(pnp, cvp, cr)) 471 goto bad; 472 } 473 474 if (++nlink > MAXSYMLINKS) { 475 error = ELOOP; 476 goto bad; 477 } 478 pn_alloc(&linkpath); 479 if (error = pn_getsymlink(cvp, &linkpath, cr)) { 480 pn_free(&linkpath); 481 goto bad; 482 } 483 484 if (audit_active) 485 audit_symlink(pnp, &linkpath); 486 487 if (pn_pathleft(&linkpath) == 0) 488 (void) pn_set(&linkpath, "."); 489 error = pn_insert(pnp, &linkpath, strlen(component)); 490 pn_free(&linkpath); 491 if (error) 492 goto bad; 493 VN_RELE(cvp); 494 cvp = NULL; 495 if (pnp->pn_pathlen == 0) { 496 error = ENOENT; 497 goto bad; 498 } 499 if (pnp->pn_path[0] == '/') { 500 do { 501 pnp->pn_path++; 502 pnp->pn_pathlen--; 503 } while (pnp->pn_path[0] == '/'); 504 VN_RELE(vp); 505 vp = rootvp; 506 VN_HOLD(vp); 507 } 508 if (audit_active) 509 audit_anchorpath(pnp, vp == rootvp); 510 if (pn_fixslash(pnp)) { 511 flags |= FOLLOW; 512 must_be_directory = 1; 513 } 514 goto next; 515 } 516 517 /* 518 * If rpnp is non-NULL, remember the resolved path name therein. 519 * Do not include "." components. Collapse occurrences of 520 * "previous/..", so long as "previous" is not itself "..". 521 * Exhausting rpnp results in error ENAMETOOLONG. 522 */ 523 if (rpnp && strcmp(component, ".") != 0) { 524 size_t len; 525 526 if (strcmp(component, "..") == 0 && 527 rpnp->pn_pathlen != 0 && 528 !((rpnp->pn_pathlen > 2 && 529 strncmp(rpnp->pn_path+rpnp->pn_pathlen-3, "/..", 3) == 0) || 530 (rpnp->pn_pathlen == 2 && 531 strncmp(rpnp->pn_path, "..", 2) == 0))) { 532 while (rpnp->pn_pathlen && 533 rpnp->pn_path[rpnp->pn_pathlen-1] != '/') 534 rpnp->pn_pathlen--; 535 if (rpnp->pn_pathlen > 1) 536 rpnp->pn_pathlen--; 537 rpnp->pn_path[rpnp->pn_pathlen] = '\0'; 538 } else { 539 if (rpnp->pn_pathlen != 0 && 540 rpnp->pn_path[rpnp->pn_pathlen-1] != '/') 541 rpnp->pn_path[rpnp->pn_pathlen++] = '/'; 542 if (flags & FIGNORECASE) { 543 /* 544 * Return the case-preserved name 545 * within the resolved path. 546 */ 547 error = copystr(pp->pn_buf, 548 rpnp->pn_path + rpnp->pn_pathlen, 549 rpnp->pn_bufsize - rpnp->pn_pathlen, &len); 550 } else { 551 error = copystr(component, 552 rpnp->pn_path + rpnp->pn_pathlen, 553 rpnp->pn_bufsize - rpnp->pn_pathlen, &len); 554 } 555 if (error) /* copystr() returns ENAMETOOLONG */ 556 goto bad; 557 rpnp->pn_pathlen += (len - 1); 558 ASSERT(rpnp->pn_bufsize > rpnp->pn_pathlen); 559 } 560 } 561 562 /* 563 * If no more components, return last directory (if wanted) and 564 * last component (if wanted). 565 */ 566 if (pn_pathleft(pnp) == 0) { 567 /* 568 * If there was a trailing slash in the pathname, 569 * make sure the last component is a directory. 570 */ 571 if (must_be_directory && cvp->v_type != VDIR) { 572 error = ENOTDIR; 573 goto bad; 574 } 575 if (dirvpp != NULL) { 576 /* 577 * Check that we have the real parent and not 578 * an alias of the last component. 579 */ 580 if (vn_compare(vp, cvp)) { 581 if (audit_active) 582 (void) audit_savepath(pnp, cvp, 583 EINVAL, cr); 584 pn_setlast(pnp); 585 VN_RELE(vp); 586 VN_RELE(cvp); 587 if (rootvp != rootdir) 588 VN_RELE(rootvp); 589 if (pp) 590 pn_free(pp); 591 return (EINVAL); 592 } 593 if (audit_active) { 594 if (error = audit_pathcomp(pnp, vp, cr)) 595 goto bad; 596 } 597 *dirvpp = vp; 598 } else 599 VN_RELE(vp); 600 if (audit_active) 601 (void) audit_savepath(pnp, cvp, 0, cr); 602 if (pnp->pn_path == pnp->pn_buf) 603 (void) pn_set(pnp, "."); 604 else 605 pn_setlast(pnp); 606 if (rpnp) { 607 if (VN_CMP(cvp, rootvp)) 608 (void) pn_set(rpnp, "/"); 609 else if (rpnp->pn_pathlen == 0) 610 (void) pn_set(rpnp, "."); 611 } 612 613 if (compvpp != NULL) 614 *compvpp = cvp; 615 else 616 VN_RELE(cvp); 617 if (rootvp != rootdir) 618 VN_RELE(rootvp); 619 if (pp) 620 pn_free(pp); 621 return (0); 622 } 623 624 if (audit_active) { 625 if (error = audit_pathcomp(pnp, cvp, cr)) 626 goto bad; 627 } 628 629 /* 630 * Skip over slashes from end of last component. 631 */ 632 while (pnp->pn_path[0] == '/') { 633 pnp->pn_path++; 634 pnp->pn_pathlen--; 635 } 636 637 /* 638 * Searched through another level of directory: 639 * release previous directory handle and save new (result 640 * of lookup) as current directory. 641 */ 642 VN_RELE(vp); 643 vp = cvp; 644 cvp = NULL; 645 goto next; 646 647 bad: 648 if (audit_active) /* reached end of path */ 649 (void) audit_savepath(pnp, cvp, error, cr); 650 bad_noaudit: 651 /* 652 * Error. Release vnodes and return. 653 */ 654 if (cvp) 655 VN_RELE(cvp); 656 /* 657 * If the error was ESTALE and the current directory to look in 658 * was the root for this lookup, the root for a mounted file 659 * system, or the starting directory for lookups, then 660 * return ENOENT instead of ESTALE. In this case, no recovery 661 * is possible by the higher level. If ESTALE was returned for 662 * some intermediate directory along the path, then recovery 663 * is potentially possible and retrying from the higher level 664 * will either correct the situation by purging stale cache 665 * entries or eventually get back to the point where no recovery 666 * is possible. 667 */ 668 if (error == ESTALE && 669 (VN_CMP(vp, rootvp) || (vp->v_flag & VROOT) || vp == startvp)) 670 error = ENOENT; 671 VN_RELE(vp); 672 if (rootvp != rootdir) 673 VN_RELE(rootvp); 674 if (pp) 675 pn_free(pp); 676 return (error); 677 } 678 679 /* 680 * Traverse a mount point. Routine accepts a vnode pointer as a reference 681 * parameter and performs the indirection, releasing the original vnode. 682 */ 683 int 684 traverse(vnode_t **cvpp) 685 { 686 int error = 0; 687 vnode_t *cvp; 688 vnode_t *tvp; 689 vfs_t *vfsp; 690 691 cvp = *cvpp; 692 693 /* 694 * If this vnode is mounted on, then we transparently indirect 695 * to the vnode which is the root of the mounted file system. 696 * Before we do this we must check that an unmount is not in 697 * progress on this vnode. 698 */ 699 700 for (;;) { 701 /* 702 * Try to read lock the vnode. If this fails because 703 * the vnode is already write locked, then check to 704 * see whether it is the current thread which locked 705 * the vnode. If it is not, then read lock the vnode 706 * by waiting to acquire the lock. 707 * 708 * The code path in domount() is an example of support 709 * which needs to look up two pathnames and locks one 710 * of them in between the two lookups. 711 */ 712 error = vn_vfsrlock(cvp); 713 if (error) { 714 if (!vn_vfswlock_held(cvp)) 715 error = vn_vfsrlock_wait(cvp); 716 if (error != 0) { 717 /* 718 * lookuppn() expects a held vnode to be 719 * returned because it promptly calls 720 * VN_RELE after the error return 721 */ 722 *cvpp = cvp; 723 return (error); 724 } 725 } 726 727 /* 728 * Reached the end of the mount chain? 729 */ 730 vfsp = vn_mountedvfs(cvp); 731 if (vfsp == NULL) { 732 vn_vfsunlock(cvp); 733 break; 734 } 735 736 /* 737 * The read lock must be held across the call to VFS_ROOT() to 738 * prevent a concurrent unmount from destroying the vfs. 739 */ 740 error = VFS_ROOT(vfsp, &tvp); 741 vn_vfsunlock(cvp); 742 743 if (error) 744 break; 745 746 VN_RELE(cvp); 747 748 cvp = tvp; 749 } 750 751 *cvpp = cvp; 752 return (error); 753 } 754 755 /* 756 * Return the lowermost vnode if this is a mountpoint. 757 */ 758 static vnode_t * 759 vn_under(vnode_t *vp) 760 { 761 vnode_t *uvp; 762 vfs_t *vfsp; 763 764 while (vp->v_flag & VROOT) { 765 766 vfsp = vp->v_vfsp; 767 vfs_rlock_wait(vfsp); 768 if ((uvp = vfsp->vfs_vnodecovered) == NULL || 769 (vfsp->vfs_flag & VFS_UNMOUNTED)) { 770 vfs_unlock(vfsp); 771 break; 772 } 773 VN_HOLD(uvp); 774 vfs_unlock(vfsp); 775 VN_RELE(vp); 776 vp = uvp; 777 } 778 779 return (vp); 780 } 781 782 static int 783 vnode_match(vnode_t *v1, vnode_t *v2, cred_t *cr) 784 { 785 vattr_t v1attr, v2attr; 786 787 /* 788 * If we have a device file, check to see if is a cloned open of the 789 * same device. For self-cloning devices, the major numbers will match. 790 * For devices cloned through the 'clone' driver, the minor number of 791 * the source device will be the same as the major number of the cloned 792 * device. 793 */ 794 if ((v1->v_type == VCHR || v1->v_type == VBLK) && 795 v1->v_type == v2->v_type) { 796 if ((spec_is_selfclone(v1) || spec_is_selfclone(v2)) && 797 getmajor(v1->v_rdev) == getmajor(v2->v_rdev)) 798 return (1); 799 800 if (spec_is_clone(v1) && 801 getmajor(v1->v_rdev) == getminor(v2->v_rdev)) 802 return (1); 803 804 if (spec_is_clone(v2) && 805 getmajor(v2->v_rdev) == getminor(v1->v_rdev)) 806 return (1); 807 } 808 809 v1attr.va_mask = v2attr.va_mask = AT_TYPE; 810 811 /* 812 * This check for symbolic links handles the pseudo-symlinks in procfs. 813 * These particular links have v_type of VDIR, but the attributes have a 814 * type of VLNK. We need to avoid these links because otherwise if we 815 * are currently in '/proc/self/fd', then '/proc/self/cwd' will compare 816 * as the same vnode. 817 */ 818 if (VOP_GETATTR(v1, &v1attr, 0, cr, NULL) != 0 || 819 VOP_GETATTR(v2, &v2attr, 0, cr, NULL) != 0 || 820 v1attr.va_type == VLNK || v2attr.va_type == VLNK) 821 return (0); 822 823 v1attr.va_mask = v2attr.va_mask = AT_TYPE | AT_FSID | AT_NODEID; 824 825 if (VOP_GETATTR(v1, &v1attr, ATTR_REAL, cr, NULL) != 0 || 826 VOP_GETATTR(v2, &v2attr, ATTR_REAL, cr, NULL) != 0) 827 return (0); 828 829 return (v1attr.va_fsid == v2attr.va_fsid && 830 v1attr.va_nodeid == v2attr.va_nodeid); 831 } 832 833 834 /* 835 * Find the entry in the directory corresponding to the target vnode. 836 */ 837 int 838 dirfindvp(vnode_t *vrootp, vnode_t *dvp, vnode_t *tvp, cred_t *cr, char *dbuf, 839 size_t dlen, dirent64_t **rdp) 840 { 841 size_t dbuflen; 842 struct iovec iov; 843 struct uio uio; 844 int error; 845 int eof; 846 vnode_t *cmpvp; 847 struct dirent64 *dp; 848 pathname_t pnp; 849 850 ASSERT(dvp->v_type == VDIR); 851 852 /* 853 * This is necessary because of the strange semantics of VOP_LOOKUP(). 854 */ 855 bzero(&pnp, sizeof (pnp)); 856 857 eof = 0; 858 859 uio.uio_iov = &iov; 860 uio.uio_iovcnt = 1; 861 uio.uio_segflg = UIO_SYSSPACE; 862 uio.uio_fmode = 0; 863 uio.uio_extflg = UIO_COPY_CACHED; 864 uio.uio_loffset = 0; 865 866 if ((error = VOP_ACCESS(dvp, VREAD, 0, cr, NULL)) != 0) 867 return (error); 868 869 while (!eof) { 870 uio.uio_resid = dlen; 871 iov.iov_base = dbuf; 872 iov.iov_len = dlen; 873 874 (void) VOP_RWLOCK(dvp, V_WRITELOCK_FALSE, NULL); 875 error = VOP_READDIR(dvp, &uio, cr, &eof, NULL, 0); 876 VOP_RWUNLOCK(dvp, V_WRITELOCK_FALSE, NULL); 877 878 dbuflen = dlen - uio.uio_resid; 879 880 if (error || dbuflen == 0) 881 break; 882 883 dp = (dirent64_t *)dbuf; 884 while ((intptr_t)dp < (intptr_t)dbuf + dbuflen) { 885 /* 886 * Ignore '.' and '..' entries 887 */ 888 if (strcmp(dp->d_name, ".") == 0 || 889 strcmp(dp->d_name, "..") == 0) { 890 dp = (dirent64_t *)((intptr_t)dp + 891 dp->d_reclen); 892 continue; 893 } 894 895 error = VOP_LOOKUP(dvp, dp->d_name, &cmpvp, &pnp, 0, 896 vrootp, cr, NULL, NULL, NULL); 897 898 /* 899 * We only want to bail out if there was an error other 900 * than ENOENT. Otherwise, it could be that someone 901 * just removed an entry since the readdir() call, and 902 * the entry we want is further on in the directory. 903 */ 904 if (error == 0) { 905 if (vnode_match(tvp, cmpvp, cr)) { 906 VN_RELE(cmpvp); 907 *rdp = dp; 908 return (0); 909 } 910 911 VN_RELE(cmpvp); 912 } else if (error != ENOENT) { 913 return (error); 914 } 915 916 dp = (dirent64_t *)((intptr_t)dp + dp->d_reclen); 917 } 918 } 919 920 /* 921 * Something strange has happened, this directory does not contain the 922 * specified vnode. This should never happen in the normal case, since 923 * we ensured that dvp is the parent of vp. This is possible in some 924 * rare conditions (races and the special .zfs directory). 925 */ 926 if (error == 0) { 927 error = VOP_LOOKUP(dvp, ".zfs", &cmpvp, &pnp, 0, vrootp, cr, 928 NULL, NULL, NULL); 929 if (error == 0) { 930 if (vnode_match(tvp, cmpvp, cr)) { 931 (void) strcpy(dp->d_name, ".zfs"); 932 dp->d_reclen = strlen(".zfs"); 933 dp->d_off = 2; 934 dp->d_ino = 1; 935 *rdp = dp; 936 } else { 937 error = ENOENT; 938 } 939 VN_RELE(cmpvp); 940 } 941 } 942 943 return (error); 944 } 945 946 /* 947 * Given a global path (from rootdir), and a vnode that is the current root, 948 * return the portion of the path that is beneath the current root or NULL on 949 * failure. The path MUST be a resolved path (no '..' entries or symlinks), 950 * otherwise this function will fail. 951 */ 952 static char * 953 localpath(char *path, struct vnode *vrootp, cred_t *cr) 954 { 955 vnode_t *vp; 956 vnode_t *cvp; 957 char component[MAXNAMELEN]; 958 char *ret = NULL; 959 pathname_t pn; 960 961 /* 962 * We use vn_compare() instead of VN_CMP() in order to detect lofs 963 * mounts and stacked vnodes. 964 */ 965 if (vn_compare(vrootp, rootdir)) 966 return (path); 967 968 if (pn_get(path, UIO_SYSSPACE, &pn) != 0) 969 return (NULL); 970 971 vp = rootdir; 972 VN_HOLD(vp); 973 974 if (vn_ismntpt(vp) && traverse(&vp) != 0) { 975 VN_RELE(vp); 976 pn_free(&pn); 977 return (NULL); 978 } 979 980 while (pn_pathleft(&pn)) { 981 pn_skipslash(&pn); 982 983 if (pn_getcomponent(&pn, component) != 0) 984 break; 985 986 if (VOP_LOOKUP(vp, component, &cvp, &pn, 0, rootdir, cr, 987 NULL, NULL, NULL) != 0) 988 break; 989 VN_RELE(vp); 990 vp = cvp; 991 992 if (vn_ismntpt(vp) && traverse(&vp) != 0) 993 break; 994 995 if (vn_compare(vp, vrootp)) { 996 ret = path + (pn.pn_path - pn.pn_buf); 997 break; 998 } 999 } 1000 1001 VN_RELE(vp); 1002 pn_free(&pn); 1003 1004 return (ret); 1005 } 1006 1007 /* 1008 * Given a directory, return the full, resolved path. This looks up "..", 1009 * searches for the given vnode in the parent, appends the component, etc. It 1010 * is used to implement vnodetopath() and getcwd() when the cached path fails 1011 * (or vfs_vnode_path is not set). 1012 */ 1013 static int 1014 dirtopath(vnode_t *vrootp, vnode_t *vp, char *buf, size_t buflen, int flags, 1015 cred_t *cr) 1016 { 1017 pathname_t pn, rpn, emptypn; 1018 vnode_t *cmpvp, *pvp = NULL; 1019 vnode_t *startvp = vp; 1020 int err = 0, vprivs; 1021 size_t complen; 1022 char *dbuf; 1023 dirent64_t *dp; 1024 char *bufloc; 1025 size_t dlen = DIRENT64_RECLEN(MAXPATHLEN); 1026 refstr_t *mntpt; 1027 1028 /* Operation only allowed on directories */ 1029 ASSERT(vp->v_type == VDIR); 1030 1031 /* We must have at least enough space for "/" */ 1032 if (buflen < 2) 1033 return (ENAMETOOLONG); 1034 1035 /* Start at end of string with terminating null */ 1036 bufloc = &buf[buflen - 1]; 1037 *bufloc = '\0'; 1038 1039 pn_alloc(&pn); 1040 pn_alloc(&rpn); 1041 dbuf = kmem_alloc(dlen, KM_SLEEP); 1042 bzero(&emptypn, sizeof (emptypn)); 1043 1044 /* 1045 * Begin with an additional reference on vp. This will be decremented 1046 * during the loop. 1047 */ 1048 VN_HOLD(vp); 1049 1050 for (;;) { 1051 /* 1052 * Return if we've reached the root. If the buffer is empty, 1053 * return '/'. We explicitly don't use vn_compare(), since it 1054 * compares the real vnodes. A lofs mount of '/' would produce 1055 * incorrect results otherwise. 1056 */ 1057 if (VN_CMP(vrootp, vp)) { 1058 if (*bufloc == '\0') 1059 *--bufloc = '/'; 1060 break; 1061 } 1062 1063 /* 1064 * If we've reached the VFS root, something has gone wrong. We 1065 * should have reached the root in the above check. The only 1066 * explantation is that 'vp' is not contained withing the given 1067 * root, in which case we return EPERM. 1068 */ 1069 if (VN_CMP(rootdir, vp)) { 1070 err = EPERM; 1071 goto out; 1072 } 1073 1074 /* 1075 * Shortcut: see if this vnode is a mountpoint. If so, 1076 * grab the path information from the vfs_t. 1077 */ 1078 if (vp->v_flag & VROOT) { 1079 1080 mntpt = vfs_getmntpoint(vp->v_vfsp); 1081 if ((err = pn_set(&pn, (char *)refstr_value(mntpt))) 1082 == 0) { 1083 refstr_rele(mntpt); 1084 rpn.pn_path = rpn.pn_buf; 1085 1086 /* 1087 * Ensure the mountpoint still exists. 1088 */ 1089 VN_HOLD(vrootp); 1090 if (vrootp != rootdir) 1091 VN_HOLD(vrootp); 1092 if (lookuppnvp(&pn, &rpn, flags, NULL, 1093 &cmpvp, vrootp, vrootp, cr) == 0) { 1094 1095 if (VN_CMP(vp, cmpvp)) { 1096 VN_RELE(cmpvp); 1097 1098 complen = strlen(rpn.pn_path); 1099 bufloc -= complen; 1100 if (bufloc < buf) { 1101 err = ERANGE; 1102 goto out; 1103 } 1104 bcopy(rpn.pn_path, bufloc, 1105 complen); 1106 break; 1107 } else { 1108 VN_RELE(cmpvp); 1109 } 1110 } 1111 } else { 1112 refstr_rele(mntpt); 1113 } 1114 } 1115 1116 /* 1117 * Shortcut: see if this vnode has correct v_path. If so, 1118 * we have the work done. 1119 */ 1120 mutex_enter(&vp->v_lock); 1121 if (vp->v_path != NULL) { 1122 1123 if ((err = pn_set(&pn, vp->v_path)) == 0) { 1124 mutex_exit(&vp->v_lock); 1125 rpn.pn_path = rpn.pn_buf; 1126 1127 /* 1128 * Ensure the v_path pointing to correct vnode 1129 */ 1130 VN_HOLD(vrootp); 1131 if (vrootp != rootdir) 1132 VN_HOLD(vrootp); 1133 if (lookuppnvp(&pn, &rpn, flags, NULL, 1134 &cmpvp, vrootp, vrootp, cr) == 0) { 1135 1136 if (VN_CMP(vp, cmpvp)) { 1137 VN_RELE(cmpvp); 1138 1139 complen = strlen(rpn.pn_path); 1140 bufloc -= complen; 1141 if (bufloc < buf) { 1142 err = ERANGE; 1143 goto out; 1144 } 1145 bcopy(rpn.pn_path, bufloc, 1146 complen); 1147 break; 1148 } else { 1149 VN_RELE(cmpvp); 1150 } 1151 } 1152 } else { 1153 mutex_exit(&vp->v_lock); 1154 } 1155 } else { 1156 mutex_exit(&vp->v_lock); 1157 } 1158 1159 /* 1160 * Shortcuts failed, search for this vnode in its parent. If 1161 * this is a mountpoint, then get the vnode underneath. 1162 */ 1163 if (vp->v_flag & VROOT) 1164 vp = vn_under(vp); 1165 if ((err = VOP_LOOKUP(vp, "..", &pvp, &emptypn, 0, vrootp, cr, 1166 NULL, NULL, NULL)) != 0) 1167 goto out; 1168 1169 /* 1170 * With extended attributes, it's possible for a directory to 1171 * have a parent that is a regular file. Check for that here. 1172 */ 1173 if (pvp->v_type != VDIR) { 1174 err = ENOTDIR; 1175 goto out; 1176 } 1177 1178 /* 1179 * If this is true, something strange has happened. This is 1180 * only true if we are the root of a filesystem, which should 1181 * have been caught by the check above. 1182 */ 1183 if (VN_CMP(pvp, vp)) { 1184 err = ENOENT; 1185 goto out; 1186 } 1187 1188 /* 1189 * Check if we have read and search privilege so, that 1190 * we can lookup the path in the directory 1191 */ 1192 vprivs = (flags & LOOKUP_CHECKREAD) ? VREAD | VEXEC : VEXEC; 1193 if ((err = VOP_ACCESS(pvp, vprivs, 0, cr, NULL)) != 0) { 1194 goto out; 1195 } 1196 1197 /* 1198 * Try to obtain the path component from dnlc cache 1199 * before searching through the directory. 1200 */ 1201 if ((cmpvp = dnlc_reverse_lookup(vp, dbuf, dlen)) != NULL) { 1202 /* 1203 * If we got parent vnode as a result, 1204 * then the answered path is correct. 1205 */ 1206 if (VN_CMP(cmpvp, pvp)) { 1207 VN_RELE(cmpvp); 1208 complen = strlen(dbuf); 1209 bufloc -= complen; 1210 if (bufloc <= buf) { 1211 err = ENAMETOOLONG; 1212 goto out; 1213 } 1214 bcopy(dbuf, bufloc, complen); 1215 1216 /* Prepend a slash to the current path */ 1217 *--bufloc = '/'; 1218 1219 /* And continue with the next component */ 1220 VN_RELE(vp); 1221 vp = pvp; 1222 pvp = NULL; 1223 continue; 1224 } else { 1225 VN_RELE(cmpvp); 1226 } 1227 } 1228 1229 /* 1230 * Search the parent directory for the entry corresponding to 1231 * this vnode. 1232 */ 1233 if ((err = dirfindvp(vrootp, pvp, vp, cr, dbuf, dlen, &dp)) 1234 != 0) 1235 goto out; 1236 complen = strlen(dp->d_name); 1237 bufloc -= complen; 1238 if (bufloc <= buf) { 1239 err = ENAMETOOLONG; 1240 goto out; 1241 } 1242 bcopy(dp->d_name, bufloc, complen); 1243 1244 /* Prepend a slash to the current path. */ 1245 *--bufloc = '/'; 1246 1247 /* And continue with the next component */ 1248 VN_RELE(vp); 1249 vp = pvp; 1250 pvp = NULL; 1251 } 1252 1253 /* 1254 * Place the path at the beginning of the buffer. 1255 */ 1256 if (bufloc != buf) 1257 ovbcopy(bufloc, buf, buflen - (bufloc - buf)); 1258 1259 /* 1260 * We got here because of invalid v_path in startvp. 1261 * Now, we have all info to fix it. 1262 * Path must not include leading slash to let vn_renamepath 1263 * pre-attach chroot'd root directory path. Also, trailing '\0' 1264 * is not counted to length. 1265 */ 1266 vn_renamepath(vrootp, startvp, &buf[1], buflen - (bufloc - buf) - 2); 1267 1268 out: 1269 /* 1270 * If the error was ESTALE and the current directory to look in 1271 * was the root for this lookup, the root for a mounted file 1272 * system, or the starting directory for lookups, then 1273 * return ENOENT instead of ESTALE. In this case, no recovery 1274 * is possible by the higher level. If ESTALE was returned for 1275 * some intermediate directory along the path, then recovery 1276 * is potentially possible and retrying from the higher level 1277 * will either correct the situation by purging stale cache 1278 * entries or eventually get back to the point where no recovery 1279 * is possible. 1280 */ 1281 if (err == ESTALE && 1282 (VN_CMP(vp, vrootp) || (vp->v_flag & VROOT) || vp == startvp)) 1283 err = ENOENT; 1284 1285 kmem_free(dbuf, dlen); 1286 VN_RELE(vp); 1287 if (pvp) 1288 VN_RELE(pvp); 1289 pn_free(&pn); 1290 pn_free(&rpn); 1291 1292 return (err); 1293 } 1294 1295 /* 1296 * The additional flag, LOOKUP_CHECKREAD, is used to enforce artificial 1297 * constraints in order to be standards compliant. For example, if we have 1298 * the cached path of '/foo/bar', and '/foo' has permissions 100 (execute 1299 * only), then we can legitimately look up the path to the current working 1300 * directory without needing read permission. Existing standards tests, 1301 * however, assume that we are determining the path by repeatedly looking up 1302 * "..". We need to keep this behavior in order to maintain backwards 1303 * compatibility. 1304 */ 1305 static int 1306 vnodetopath_common(vnode_t *vrootp, vnode_t *vp, char *buf, size_t buflen, 1307 cred_t *cr, int flags) 1308 { 1309 pathname_t pn, rpn; 1310 int ret, len; 1311 vnode_t *compvp, *pvp, *realvp; 1312 proc_t *p = curproc; 1313 char path[MAXNAMELEN]; 1314 int doclose = 0; 1315 1316 /* 1317 * If vrootp is NULL, get the root for curproc. Callers with any other 1318 * requirements should pass in a different vrootp. 1319 */ 1320 if (vrootp == NULL) { 1321 mutex_enter(&p->p_lock); 1322 if ((vrootp = PTOU(p)->u_rdir) == NULL) 1323 vrootp = rootdir; 1324 VN_HOLD(vrootp); 1325 mutex_exit(&p->p_lock); 1326 } else { 1327 VN_HOLD(vrootp); 1328 } 1329 1330 /* 1331 * This is to get around an annoying artifact of the /proc filesystem, 1332 * which is the behavior of {cwd/root}. Trying to resolve this path 1333 * will result in /proc/pid/cwd instead of whatever the real working 1334 * directory is. We can't rely on VOP_REALVP(), since that will break 1335 * lofs. The only difference between procfs and lofs is that opening 1336 * the file will return the underling vnode in the case of procfs. 1337 */ 1338 if (vp->v_type == VDIR && VOP_REALVP(vp, &realvp, NULL) == 0 && 1339 realvp != vp) { 1340 VN_HOLD(vp); 1341 if (VOP_OPEN(&vp, FREAD, cr, NULL) == 0) 1342 doclose = 1; 1343 else 1344 VN_RELE(vp); 1345 } 1346 1347 pn_alloc(&pn); 1348 1349 /* 1350 * Check to see if we have a cached path in the vnode. 1351 */ 1352 mutex_enter(&vp->v_lock); 1353 if (vp->v_path != NULL) { 1354 (void) pn_set(&pn, vp->v_path); 1355 mutex_exit(&vp->v_lock); 1356 1357 pn_alloc(&rpn); 1358 1359 /* We should only cache absolute paths */ 1360 ASSERT(pn.pn_buf[0] == '/'); 1361 1362 /* 1363 * If we are in a zone or a chroot environment, then we have to 1364 * take additional steps, since the path to the root might not 1365 * be readable with the current credentials, even though the 1366 * process can legitmately access the file. In this case, we 1367 * do the following: 1368 * 1369 * lookuppnvp() with all privileges to get the resolved path. 1370 * call localpath() to get the local portion of the path, and 1371 * continue as normal. 1372 * 1373 * If the the conversion to a local path fails, then we continue 1374 * as normal. This is a heuristic to make process object file 1375 * paths available from within a zone. Because lofs doesn't 1376 * support page operations, the vnode stored in the seg_t is 1377 * actually the underlying real vnode, not the lofs node itself. 1378 * Most of the time, the lofs path is the same as the underlying 1379 * vnode (for example, /usr/lib/libc.so.1). 1380 */ 1381 if (vrootp != rootdir) { 1382 char *local = NULL; 1383 VN_HOLD(rootdir); 1384 if (lookuppnvp(&pn, &rpn, FOLLOW, 1385 NULL, &compvp, rootdir, rootdir, kcred) == 0) { 1386 local = localpath(rpn.pn_path, vrootp, 1387 kcred); 1388 VN_RELE(compvp); 1389 } 1390 1391 /* 1392 * The original pn was changed through lookuppnvp(). 1393 * Set it to local for next validation attempt. 1394 */ 1395 if (local) { 1396 (void) pn_set(&pn, local); 1397 } else { 1398 goto notcached; 1399 } 1400 } 1401 1402 /* 1403 * We should have a local path at this point, so start the 1404 * search from the root of the current process. 1405 */ 1406 VN_HOLD(vrootp); 1407 if (vrootp != rootdir) 1408 VN_HOLD(vrootp); 1409 ret = lookuppnvp(&pn, &rpn, FOLLOW | flags, NULL, 1410 &compvp, vrootp, vrootp, cr); 1411 if (ret == 0) { 1412 /* 1413 * Check to see if the returned vnode is the same as 1414 * the one we expect. If not, give up. 1415 */ 1416 if (!vn_compare(vp, compvp) && 1417 !vnode_match(vp, compvp, cr)) { 1418 VN_RELE(compvp); 1419 goto notcached; 1420 } 1421 1422 VN_RELE(compvp); 1423 1424 /* 1425 * Return the result. 1426 */ 1427 if (buflen <= rpn.pn_pathlen) 1428 goto notcached; 1429 1430 bcopy(rpn.pn_path, buf, rpn.pn_pathlen + 1); 1431 pn_free(&pn); 1432 pn_free(&rpn); 1433 VN_RELE(vrootp); 1434 if (doclose) { 1435 (void) VOP_CLOSE(vp, FREAD, 1, 0, cr, NULL); 1436 VN_RELE(vp); 1437 } 1438 return (0); 1439 } 1440 1441 notcached: 1442 pn_free(&rpn); 1443 } else { 1444 mutex_exit(&vp->v_lock); 1445 } 1446 1447 pn_free(&pn); 1448 1449 if (vp->v_type != VDIR) { 1450 /* 1451 * If we don't have a directory, try to find it in the dnlc via 1452 * reverse lookup. Once this is found, we can use the regular 1453 * directory search to find the full path. 1454 */ 1455 if ((pvp = dnlc_reverse_lookup(vp, path, MAXNAMELEN)) != NULL) { 1456 /* 1457 * Check if we have read privilege so, that 1458 * we can lookup the path in the directory 1459 */ 1460 ret = 0; 1461 if ((flags & LOOKUP_CHECKREAD)) { 1462 ret = VOP_ACCESS(pvp, VREAD, 0, cr, NULL); 1463 } 1464 if (ret == 0) { 1465 ret = dirtopath(vrootp, pvp, buf, buflen, 1466 flags, cr); 1467 } 1468 if (ret == 0) { 1469 len = strlen(buf); 1470 if (len + strlen(path) + 1 >= buflen) { 1471 ret = ENAMETOOLONG; 1472 } else { 1473 if (buf[len - 1] != '/') 1474 buf[len++] = '/'; 1475 bcopy(path, buf + len, 1476 strlen(path) + 1); 1477 } 1478 } 1479 1480 VN_RELE(pvp); 1481 } else 1482 ret = ENOENT; 1483 } else 1484 ret = dirtopath(vrootp, vp, buf, buflen, flags, cr); 1485 1486 VN_RELE(vrootp); 1487 if (doclose) { 1488 (void) VOP_CLOSE(vp, FREAD, 1, 0, cr, NULL); 1489 VN_RELE(vp); 1490 } 1491 1492 return (ret); 1493 } 1494 1495 int 1496 vnodetopath(vnode_t *vrootp, vnode_t *vp, char *buf, size_t buflen, cred_t *cr) 1497 { 1498 return (vnodetopath_common(vrootp, vp, buf, buflen, cr, 0)); 1499 } 1500 1501 int 1502 dogetcwd(char *buf, size_t buflen) 1503 { 1504 int ret; 1505 vnode_t *vp; 1506 vnode_t *compvp; 1507 refstr_t *cwd, *oldcwd; 1508 const char *value; 1509 pathname_t rpnp, pnp; 1510 proc_t *p = curproc; 1511 1512 /* 1513 * Check to see if there is a cached version of the cwd. If so, lookup 1514 * the cached value and make sure it is the same vnode. 1515 */ 1516 mutex_enter(&p->p_lock); 1517 if ((cwd = PTOU(p)->u_cwd) != NULL) 1518 refstr_hold(cwd); 1519 vp = PTOU(p)->u_cdir; 1520 VN_HOLD(vp); 1521 mutex_exit(&p->p_lock); 1522 1523 /* 1524 * Make sure we have permission to access the current directory. 1525 */ 1526 if ((ret = VOP_ACCESS(vp, VEXEC, 0, CRED(), NULL)) != 0) { 1527 if (cwd != NULL) 1528 refstr_rele(cwd); 1529 VN_RELE(vp); 1530 return (ret); 1531 } 1532 1533 if (cwd) { 1534 value = refstr_value(cwd); 1535 if ((ret = pn_get((char *)value, UIO_SYSSPACE, &pnp)) != 0) { 1536 refstr_rele(cwd); 1537 VN_RELE(vp); 1538 return (ret); 1539 } 1540 1541 pn_alloc(&rpnp); 1542 1543 if (lookuppn(&pnp, &rpnp, NO_FOLLOW, NULL, &compvp) == 0) { 1544 1545 if (VN_CMP(vp, compvp) && 1546 strcmp(value, rpnp.pn_path) == 0) { 1547 VN_RELE(compvp); 1548 VN_RELE(vp); 1549 pn_free(&pnp); 1550 pn_free(&rpnp); 1551 if (strlen(value) + 1 > buflen) { 1552 refstr_rele(cwd); 1553 return (ENAMETOOLONG); 1554 } 1555 bcopy(value, buf, strlen(value) + 1); 1556 refstr_rele(cwd); 1557 return (0); 1558 } 1559 1560 VN_RELE(compvp); 1561 } 1562 1563 pn_free(&rpnp); 1564 pn_free(&pnp); 1565 1566 refstr_rele(cwd); 1567 } 1568 1569 ret = vnodetopath_common(NULL, vp, buf, buflen, CRED(), 1570 LOOKUP_CHECKREAD); 1571 1572 VN_RELE(vp); 1573 1574 /* 1575 * Store the new cwd and replace the existing cached copy. 1576 */ 1577 if (ret == 0) 1578 cwd = refstr_alloc(buf); 1579 else 1580 cwd = NULL; 1581 1582 mutex_enter(&p->p_lock); 1583 oldcwd = PTOU(p)->u_cwd; 1584 PTOU(p)->u_cwd = cwd; 1585 mutex_exit(&p->p_lock); 1586 1587 if (oldcwd) 1588 refstr_rele(oldcwd); 1589 1590 return (ret); 1591 } 1592