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 2010 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 (AU_AUDITING()) 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 uint32_t auditing = AU_AUDITING(); 234 235 CPU_STATS_ADDQ(CPU, sys, namei, 1); 236 nlink = 0; 237 cvp = NULL; 238 if (rpnp) 239 rpnp->pn_pathlen = 0; 240 241 lookup_flags = dirvpp ? LOOKUP_DIR : 0; 242 if (flags & FIGNORECASE) { 243 lookup_flags |= FIGNORECASE; 244 pn_alloc(&presrvd); 245 pp = &presrvd; 246 } 247 248 if (auditing) 249 audit_anchorpath(pnp, vp == rootvp); 250 251 /* 252 * Eliminate any trailing slashes in the pathname. 253 * If there are any, we must follow all symlinks. 254 * Also, we must guarantee that the last component is a directory. 255 */ 256 if (pn_fixslash(pnp)) { 257 flags |= FOLLOW; 258 must_be_directory = 1; 259 } 260 261 startvp = vp; 262 next: 263 retry_with_kcred = B_FALSE; 264 265 /* 266 * Make sure we have a directory. 267 */ 268 if (vp->v_type != VDIR) { 269 error = ENOTDIR; 270 goto bad; 271 } 272 273 if (rpnp && VN_CMP(vp, rootvp)) 274 (void) pn_set(rpnp, "/"); 275 276 /* 277 * Process the next component of the pathname. 278 */ 279 if (error = pn_getcomponent(pnp, component)) { 280 if (auditing) 281 audit_addcomponent(pnp); 282 goto bad; 283 } 284 285 /* 286 * Handle "..": two special cases. 287 * 1. If we're at the root directory (e.g. after chroot or 288 * zone_enter) then change ".." to "." so we can't get 289 * out of this subtree. 290 * 2. If this vnode is the root of a mounted file system, 291 * then replace it with the vnode that was mounted on 292 * so that we take the ".." in the other file system. 293 */ 294 if (component[0] == '.' && component[1] == '.' && component[2] == 0) { 295 checkforroot: 296 if (VN_CMP(vp, rootvp) || VN_CMP(vp, zonevp)) { 297 component[1] = '\0'; 298 } else if (vp->v_flag & VROOT) { 299 vfs_t *vfsp; 300 cvp = vp; 301 302 /* 303 * While we deal with the vfs pointer from the vnode 304 * the filesystem could have been forcefully unmounted 305 * and the vnode's v_vfsp could have been invalidated 306 * by VFS_UNMOUNT. Hence, we cache v_vfsp and use it 307 * with vfs_rlock_wait/vfs_unlock. 308 * It is safe to use the v_vfsp even it is freed by 309 * VFS_UNMOUNT because vfs_rlock_wait/vfs_unlock 310 * do not dereference v_vfsp. It is just used as a 311 * magic cookie. 312 * One more corner case here is the memory getting 313 * reused for another vfs structure. In this case 314 * lookuppnvp's vfs_rlock_wait will succeed, domount's 315 * vfs_lock will fail and domount will bail out with an 316 * error (EBUSY). 317 */ 318 vfsp = cvp->v_vfsp; 319 320 /* 321 * This lock is used to synchronize 322 * mounts/unmounts and lookups. 323 * Threads doing mounts/unmounts hold the 324 * writers version vfs_lock_wait(). 325 */ 326 327 vfs_rlock_wait(vfsp); 328 329 /* 330 * If this vnode is on a file system that 331 * has been forcibly unmounted, 332 * we can't proceed. Cancel this operation 333 * and return EIO. 334 * 335 * vfs_vnodecovered is NULL if unmounted. 336 * Currently, nfs uses VFS_UNMOUNTED to 337 * check if it's a forced-umount. Keep the 338 * same checking here as well even though it 339 * may not be needed. 340 */ 341 if (((vp = cvp->v_vfsp->vfs_vnodecovered) == NULL) || 342 (cvp->v_vfsp->vfs_flag & VFS_UNMOUNTED)) { 343 vfs_unlock(vfsp); 344 VN_RELE(cvp); 345 if (pp) 346 pn_free(pp); 347 return (EIO); 348 } 349 VN_HOLD(vp); 350 vfs_unlock(vfsp); 351 VN_RELE(cvp); 352 cvp = NULL; 353 /* 354 * Crossing mount points. For eg: We are doing 355 * a lookup of ".." for file systems root vnode 356 * mounted here, and VOP_LOOKUP() (with covered vnode) 357 * will be on underlying file systems mount point 358 * vnode. Set retry_with_kcred flag as we might end 359 * up doing VOP_LOOKUP() with kcred if required. 360 */ 361 retry_with_kcred = B_TRUE; 362 goto checkforroot; 363 } 364 } 365 366 /* 367 * LOOKUP_CHECKREAD is a private flag used by vnodetopath() to indicate 368 * that we need to have read permission on every directory in the entire 369 * path. This is used to ensure that a forward-lookup of a cached value 370 * has the same effect as a reverse-lookup when the cached value cannot 371 * be found. 372 */ 373 if ((flags & LOOKUP_CHECKREAD) && 374 (error = VOP_ACCESS(vp, VREAD, 0, cr, NULL)) != 0) 375 goto bad; 376 377 /* 378 * Perform a lookup in the current directory. 379 */ 380 error = VOP_LOOKUP(vp, component, &tvp, pnp, lookup_flags, 381 rootvp, cr, NULL, NULL, pp); 382 383 /* 384 * Retry with kcred - If crossing mount points & error is EACCES. 385 * 386 * If we are crossing mount points here and doing ".." lookup, 387 * VOP_LOOKUP() might fail if the underlying file systems 388 * mount point has no execute permission. In cases like these, 389 * we retry VOP_LOOKUP() by giving as much privilage as possible 390 * by passing kcred credentials. 391 * 392 * In case of hierarchical file systems, passing kcred still may 393 * or may not work. 394 * For eg: UFS FS --> Mount NFS FS --> Again mount UFS on some 395 * directory inside NFS FS. 396 */ 397 if ((error == EACCES) && retry_with_kcred) 398 error = VOP_LOOKUP(vp, component, &tvp, pnp, lookup_flags, 399 rootvp, zone_kcred(), NULL, NULL, pp); 400 401 cvp = tvp; 402 if (error) { 403 cvp = NULL; 404 /* 405 * On error, return hard error if 406 * (a) we're not at the end of the pathname yet, or 407 * (b) the caller didn't want the parent directory, or 408 * (c) we failed for some reason other than a missing entry. 409 */ 410 if (pn_pathleft(pnp) || dirvpp == NULL || error != ENOENT) 411 goto bad; 412 if (auditing) { /* directory access */ 413 if (error = audit_savepath(pnp, vp, error, cr)) 414 goto bad_noaudit; 415 } 416 pn_setlast(pnp); 417 /* 418 * We inform the caller that the desired entry must be 419 * a directory by adding a '/' to the component name. 420 */ 421 if (must_be_directory && (error = pn_addslash(pnp)) != 0) 422 goto bad; 423 *dirvpp = vp; 424 if (compvpp != NULL) 425 *compvpp = NULL; 426 if (rootvp != rootdir) 427 VN_RELE(rootvp); 428 if (pp) 429 pn_free(pp); 430 return (0); 431 } 432 433 /* 434 * Traverse mount points. 435 * XXX why don't we need to hold a read lock here (call vn_vfsrlock)? 436 * What prevents a concurrent update to v_vfsmountedhere? 437 * Possible answer: if mounting, we might not see the mount 438 * if it is concurrently coming into existence, but that's 439 * really not much different from the thread running a bit slower. 440 * If unmounting, we may get into traverse() when we shouldn't, 441 * but traverse() will catch this case for us. 442 * (For this to work, fetching v_vfsmountedhere had better 443 * be atomic!) 444 */ 445 if (vn_mountedvfs(cvp) != NULL) { 446 tvp = cvp; 447 if ((error = traverse(&tvp)) != 0) { 448 /* 449 * It is required to assign cvp here, because 450 * traverse() will return a held vnode which 451 * may different than the vnode that was passed 452 * in (even in the error case). If traverse() 453 * changes the vnode it releases the original, 454 * and holds the new one. 455 */ 456 cvp = tvp; 457 goto bad; 458 } 459 cvp = tvp; 460 } 461 462 /* 463 * If we hit a symbolic link and there is more path to be 464 * translated or this operation does not wish to apply 465 * to a link, then place the contents of the link at the 466 * front of the remaining pathname. 467 */ 468 if (cvp->v_type == VLNK && ((flags & FOLLOW) || pn_pathleft(pnp))) { 469 struct pathname linkpath; 470 if (auditing) { 471 if (error = audit_pathcomp(pnp, cvp, cr)) 472 goto bad; 473 } 474 475 if (++nlink > MAXSYMLINKS) { 476 error = ELOOP; 477 goto bad; 478 } 479 pn_alloc(&linkpath); 480 if (error = pn_getsymlink(cvp, &linkpath, cr)) { 481 pn_free(&linkpath); 482 goto bad; 483 } 484 485 if (auditing) 486 audit_symlink(pnp, &linkpath); 487 488 if (pn_pathleft(&linkpath) == 0) 489 (void) pn_set(&linkpath, "."); 490 error = pn_insert(pnp, &linkpath, strlen(component)); 491 pn_free(&linkpath); 492 if (error) 493 goto bad; 494 VN_RELE(cvp); 495 cvp = NULL; 496 if (pnp->pn_pathlen == 0) { 497 error = ENOENT; 498 goto bad; 499 } 500 if (pnp->pn_path[0] == '/') { 501 do { 502 pnp->pn_path++; 503 pnp->pn_pathlen--; 504 } while (pnp->pn_path[0] == '/'); 505 VN_RELE(vp); 506 vp = rootvp; 507 VN_HOLD(vp); 508 } 509 if (auditing) 510 audit_anchorpath(pnp, vp == rootvp); 511 if (pn_fixslash(pnp)) { 512 flags |= FOLLOW; 513 must_be_directory = 1; 514 } 515 goto next; 516 } 517 518 /* 519 * If rpnp is non-NULL, remember the resolved path name therein. 520 * Do not include "." components. Collapse occurrences of 521 * "previous/..", so long as "previous" is not itself "..". 522 * Exhausting rpnp results in error ENAMETOOLONG. 523 */ 524 if (rpnp && strcmp(component, ".") != 0) { 525 size_t len; 526 527 if (strcmp(component, "..") == 0 && 528 rpnp->pn_pathlen != 0 && 529 !((rpnp->pn_pathlen > 2 && 530 strncmp(rpnp->pn_path+rpnp->pn_pathlen-3, "/..", 3) == 0) || 531 (rpnp->pn_pathlen == 2 && 532 strncmp(rpnp->pn_path, "..", 2) == 0))) { 533 while (rpnp->pn_pathlen && 534 rpnp->pn_path[rpnp->pn_pathlen-1] != '/') 535 rpnp->pn_pathlen--; 536 if (rpnp->pn_pathlen > 1) 537 rpnp->pn_pathlen--; 538 rpnp->pn_path[rpnp->pn_pathlen] = '\0'; 539 } else { 540 if (rpnp->pn_pathlen != 0 && 541 rpnp->pn_path[rpnp->pn_pathlen-1] != '/') 542 rpnp->pn_path[rpnp->pn_pathlen++] = '/'; 543 if (flags & FIGNORECASE) { 544 /* 545 * Return the case-preserved name 546 * within the resolved path. 547 */ 548 error = copystr(pp->pn_buf, 549 rpnp->pn_path + rpnp->pn_pathlen, 550 rpnp->pn_bufsize - rpnp->pn_pathlen, &len); 551 } else { 552 error = copystr(component, 553 rpnp->pn_path + rpnp->pn_pathlen, 554 rpnp->pn_bufsize - rpnp->pn_pathlen, &len); 555 } 556 if (error) /* copystr() returns ENAMETOOLONG */ 557 goto bad; 558 rpnp->pn_pathlen += (len - 1); 559 ASSERT(rpnp->pn_bufsize > rpnp->pn_pathlen); 560 } 561 } 562 563 /* 564 * If no more components, return last directory (if wanted) and 565 * last component (if wanted). 566 */ 567 if (pn_pathleft(pnp) == 0) { 568 /* 569 * If there was a trailing slash in the pathname, 570 * make sure the last component is a directory. 571 */ 572 if (must_be_directory && cvp->v_type != VDIR) { 573 error = ENOTDIR; 574 goto bad; 575 } 576 if (dirvpp != NULL) { 577 /* 578 * Check that we have the real parent and not 579 * an alias of the last component. 580 */ 581 if (vn_compare(vp, cvp)) { 582 if (auditing) 583 (void) audit_savepath(pnp, cvp, 584 EINVAL, cr); 585 pn_setlast(pnp); 586 VN_RELE(vp); 587 VN_RELE(cvp); 588 if (rootvp != rootdir) 589 VN_RELE(rootvp); 590 if (pp) 591 pn_free(pp); 592 return (EINVAL); 593 } 594 if (auditing) { 595 if (error = audit_pathcomp(pnp, vp, cr)) 596 goto bad; 597 } 598 *dirvpp = vp; 599 } else 600 VN_RELE(vp); 601 if (auditing) 602 (void) audit_savepath(pnp, cvp, 0, cr); 603 if (pnp->pn_path == pnp->pn_buf) 604 (void) pn_set(pnp, "."); 605 else 606 pn_setlast(pnp); 607 if (rpnp) { 608 if (VN_CMP(cvp, rootvp)) 609 (void) pn_set(rpnp, "/"); 610 else if (rpnp->pn_pathlen == 0) 611 (void) pn_set(rpnp, "."); 612 } 613 614 if (compvpp != NULL) 615 *compvpp = cvp; 616 else 617 VN_RELE(cvp); 618 if (rootvp != rootdir) 619 VN_RELE(rootvp); 620 if (pp) 621 pn_free(pp); 622 return (0); 623 } 624 625 if (auditing) { 626 if (error = audit_pathcomp(pnp, cvp, cr)) 627 goto bad; 628 } 629 630 /* 631 * Skip over slashes from end of last component. 632 */ 633 while (pnp->pn_path[0] == '/') { 634 pnp->pn_path++; 635 pnp->pn_pathlen--; 636 } 637 638 /* 639 * Searched through another level of directory: 640 * release previous directory handle and save new (result 641 * of lookup) as current directory. 642 */ 643 VN_RELE(vp); 644 vp = cvp; 645 cvp = NULL; 646 goto next; 647 648 bad: 649 if (auditing) /* reached end of path */ 650 (void) audit_savepath(pnp, cvp, error, cr); 651 bad_noaudit: 652 /* 653 * Error. Release vnodes and return. 654 */ 655 if (cvp) 656 VN_RELE(cvp); 657 /* 658 * If the error was ESTALE and the current directory to look in 659 * was the root for this lookup, the root for a mounted file 660 * system, or the starting directory for lookups, then 661 * return ENOENT instead of ESTALE. In this case, no recovery 662 * is possible by the higher level. If ESTALE was returned for 663 * some intermediate directory along the path, then recovery 664 * is potentially possible and retrying from the higher level 665 * will either correct the situation by purging stale cache 666 * entries or eventually get back to the point where no recovery 667 * is possible. 668 */ 669 if (error == ESTALE && 670 (VN_CMP(vp, rootvp) || (vp->v_flag & VROOT) || vp == startvp)) 671 error = ENOENT; 672 VN_RELE(vp); 673 if (rootvp != rootdir) 674 VN_RELE(rootvp); 675 if (pp) 676 pn_free(pp); 677 return (error); 678 } 679 680 /* 681 * Traverse a mount point. Routine accepts a vnode pointer as a reference 682 * parameter and performs the indirection, releasing the original vnode. 683 */ 684 int 685 traverse(vnode_t **cvpp) 686 { 687 int error = 0; 688 vnode_t *cvp; 689 vnode_t *tvp; 690 vfs_t *vfsp; 691 692 cvp = *cvpp; 693 694 /* 695 * If this vnode is mounted on, then we transparently indirect 696 * to the vnode which is the root of the mounted file system. 697 * Before we do this we must check that an unmount is not in 698 * progress on this vnode. 699 */ 700 701 for (;;) { 702 /* 703 * Try to read lock the vnode. If this fails because 704 * the vnode is already write locked, then check to 705 * see whether it is the current thread which locked 706 * the vnode. If it is not, then read lock the vnode 707 * by waiting to acquire the lock. 708 * 709 * The code path in domount() is an example of support 710 * which needs to look up two pathnames and locks one 711 * of them in between the two lookups. 712 */ 713 error = vn_vfsrlock(cvp); 714 if (error) { 715 if (!vn_vfswlock_held(cvp)) 716 error = vn_vfsrlock_wait(cvp); 717 if (error != 0) { 718 /* 719 * lookuppn() expects a held vnode to be 720 * returned because it promptly calls 721 * VN_RELE after the error return 722 */ 723 *cvpp = cvp; 724 return (error); 725 } 726 } 727 728 /* 729 * Reached the end of the mount chain? 730 */ 731 vfsp = vn_mountedvfs(cvp); 732 if (vfsp == NULL) { 733 vn_vfsunlock(cvp); 734 break; 735 } 736 737 /* 738 * The read lock must be held across the call to VFS_ROOT() to 739 * prevent a concurrent unmount from destroying the vfs. 740 */ 741 error = VFS_ROOT(vfsp, &tvp); 742 vn_vfsunlock(cvp); 743 744 if (error) 745 break; 746 747 VN_RELE(cvp); 748 749 cvp = tvp; 750 } 751 752 *cvpp = cvp; 753 return (error); 754 } 755 756 /* 757 * Return the lowermost vnode if this is a mountpoint. 758 */ 759 static vnode_t * 760 vn_under(vnode_t *vp) 761 { 762 vnode_t *uvp; 763 vfs_t *vfsp; 764 765 while (vp->v_flag & VROOT) { 766 767 vfsp = vp->v_vfsp; 768 vfs_rlock_wait(vfsp); 769 if ((uvp = vfsp->vfs_vnodecovered) == NULL || 770 (vfsp->vfs_flag & VFS_UNMOUNTED)) { 771 vfs_unlock(vfsp); 772 break; 773 } 774 VN_HOLD(uvp); 775 vfs_unlock(vfsp); 776 VN_RELE(vp); 777 vp = uvp; 778 } 779 780 return (vp); 781 } 782 783 static int 784 vnode_match(vnode_t *v1, vnode_t *v2, cred_t *cr) 785 { 786 vattr_t v1attr, v2attr; 787 788 /* 789 * If we have a device file, check to see if is a cloned open of the 790 * same device. For self-cloning devices, the major numbers will match. 791 * For devices cloned through the 'clone' driver, the minor number of 792 * the source device will be the same as the major number of the cloned 793 * device. 794 */ 795 if ((v1->v_type == VCHR || v1->v_type == VBLK) && 796 v1->v_type == v2->v_type) { 797 if ((spec_is_selfclone(v1) || spec_is_selfclone(v2)) && 798 getmajor(v1->v_rdev) == getmajor(v2->v_rdev)) 799 return (1); 800 801 if (spec_is_clone(v1) && 802 getmajor(v1->v_rdev) == getminor(v2->v_rdev)) 803 return (1); 804 805 if (spec_is_clone(v2) && 806 getmajor(v2->v_rdev) == getminor(v1->v_rdev)) 807 return (1); 808 } 809 810 v1attr.va_mask = v2attr.va_mask = AT_TYPE; 811 812 /* 813 * This check for symbolic links handles the pseudo-symlinks in procfs. 814 * These particular links have v_type of VDIR, but the attributes have a 815 * type of VLNK. We need to avoid these links because otherwise if we 816 * are currently in '/proc/self/fd', then '/proc/self/cwd' will compare 817 * as the same vnode. 818 */ 819 if (VOP_GETATTR(v1, &v1attr, 0, cr, NULL) != 0 || 820 VOP_GETATTR(v2, &v2attr, 0, cr, NULL) != 0 || 821 v1attr.va_type == VLNK || v2attr.va_type == VLNK) 822 return (0); 823 824 v1attr.va_mask = v2attr.va_mask = AT_TYPE | AT_FSID | AT_NODEID; 825 826 if (VOP_GETATTR(v1, &v1attr, ATTR_REAL, cr, NULL) != 0 || 827 VOP_GETATTR(v2, &v2attr, ATTR_REAL, cr, NULL) != 0) 828 return (0); 829 830 return (v1attr.va_fsid == v2attr.va_fsid && 831 v1attr.va_nodeid == v2attr.va_nodeid); 832 } 833 834 835 /* 836 * Find the entry in the directory corresponding to the target vnode. 837 */ 838 int 839 dirfindvp(vnode_t *vrootp, vnode_t *dvp, vnode_t *tvp, cred_t *cr, char *dbuf, 840 size_t dlen, dirent64_t **rdp) 841 { 842 size_t dbuflen; 843 struct iovec iov; 844 struct uio uio; 845 int error; 846 int eof; 847 vnode_t *cmpvp; 848 struct dirent64 *dp; 849 pathname_t pnp; 850 851 ASSERT(dvp->v_type == VDIR); 852 853 /* 854 * This is necessary because of the strange semantics of VOP_LOOKUP(). 855 */ 856 bzero(&pnp, sizeof (pnp)); 857 858 eof = 0; 859 860 uio.uio_iov = &iov; 861 uio.uio_iovcnt = 1; 862 uio.uio_segflg = UIO_SYSSPACE; 863 uio.uio_fmode = 0; 864 uio.uio_extflg = UIO_COPY_CACHED; 865 uio.uio_loffset = 0; 866 867 if ((error = VOP_ACCESS(dvp, VREAD, 0, cr, NULL)) != 0) 868 return (error); 869 870 while (!eof) { 871 uio.uio_resid = dlen; 872 iov.iov_base = dbuf; 873 iov.iov_len = dlen; 874 875 (void) VOP_RWLOCK(dvp, V_WRITELOCK_FALSE, NULL); 876 error = VOP_READDIR(dvp, &uio, cr, &eof, NULL, 0); 877 VOP_RWUNLOCK(dvp, V_WRITELOCK_FALSE, NULL); 878 879 dbuflen = dlen - uio.uio_resid; 880 881 if (error || dbuflen == 0) 882 break; 883 884 dp = (dirent64_t *)dbuf; 885 while ((intptr_t)dp < (intptr_t)dbuf + dbuflen) { 886 /* 887 * Ignore '.' and '..' entries 888 */ 889 if (strcmp(dp->d_name, ".") == 0 || 890 strcmp(dp->d_name, "..") == 0) { 891 dp = (dirent64_t *)((intptr_t)dp + 892 dp->d_reclen); 893 continue; 894 } 895 896 error = VOP_LOOKUP(dvp, dp->d_name, &cmpvp, &pnp, 0, 897 vrootp, cr, NULL, NULL, NULL); 898 899 /* 900 * We only want to bail out if there was an error other 901 * than ENOENT. Otherwise, it could be that someone 902 * just removed an entry since the readdir() call, and 903 * the entry we want is further on in the directory. 904 */ 905 if (error == 0) { 906 if (vnode_match(tvp, cmpvp, cr)) { 907 VN_RELE(cmpvp); 908 *rdp = dp; 909 return (0); 910 } 911 912 VN_RELE(cmpvp); 913 } else if (error != ENOENT) { 914 return (error); 915 } 916 917 dp = (dirent64_t *)((intptr_t)dp + dp->d_reclen); 918 } 919 } 920 921 /* 922 * Something strange has happened, this directory does not contain the 923 * specified vnode. This should never happen in the normal case, since 924 * we ensured that dvp is the parent of vp. This is possible in some 925 * rare conditions (races and the special .zfs directory). 926 */ 927 if (error == 0) { 928 error = VOP_LOOKUP(dvp, ".zfs", &cmpvp, &pnp, 0, vrootp, cr, 929 NULL, NULL, NULL); 930 if (error == 0) { 931 if (vnode_match(tvp, cmpvp, cr)) { 932 (void) strcpy(dp->d_name, ".zfs"); 933 dp->d_reclen = strlen(".zfs"); 934 dp->d_off = 2; 935 dp->d_ino = 1; 936 *rdp = dp; 937 } else { 938 error = ENOENT; 939 } 940 VN_RELE(cmpvp); 941 } 942 } 943 944 return (error); 945 } 946 947 /* 948 * Given a global path (from rootdir), and a vnode that is the current root, 949 * return the portion of the path that is beneath the current root or NULL on 950 * failure. The path MUST be a resolved path (no '..' entries or symlinks), 951 * otherwise this function will fail. 952 */ 953 static char * 954 localpath(char *path, struct vnode *vrootp, cred_t *cr) 955 { 956 vnode_t *vp; 957 vnode_t *cvp; 958 char component[MAXNAMELEN]; 959 char *ret = NULL; 960 pathname_t pn; 961 962 /* 963 * We use vn_compare() instead of VN_CMP() in order to detect lofs 964 * mounts and stacked vnodes. 965 */ 966 if (vn_compare(vrootp, rootdir)) 967 return (path); 968 969 if (pn_get(path, UIO_SYSSPACE, &pn) != 0) 970 return (NULL); 971 972 vp = rootdir; 973 VN_HOLD(vp); 974 975 if (vn_ismntpt(vp) && traverse(&vp) != 0) { 976 VN_RELE(vp); 977 pn_free(&pn); 978 return (NULL); 979 } 980 981 while (pn_pathleft(&pn)) { 982 pn_skipslash(&pn); 983 984 if (pn_getcomponent(&pn, component) != 0) 985 break; 986 987 if (VOP_LOOKUP(vp, component, &cvp, &pn, 0, rootdir, cr, 988 NULL, NULL, NULL) != 0) 989 break; 990 VN_RELE(vp); 991 vp = cvp; 992 993 if (vn_ismntpt(vp) && traverse(&vp) != 0) 994 break; 995 996 if (vn_compare(vp, vrootp)) { 997 ret = path + (pn.pn_path - pn.pn_buf); 998 break; 999 } 1000 } 1001 1002 VN_RELE(vp); 1003 pn_free(&pn); 1004 1005 return (ret); 1006 } 1007 1008 /* 1009 * Given a directory, return the full, resolved path. This looks up "..", 1010 * searches for the given vnode in the parent, appends the component, etc. It 1011 * is used to implement vnodetopath() and getcwd() when the cached path fails 1012 * (or vfs_vnode_path is not set). 1013 */ 1014 static int 1015 dirtopath(vnode_t *vrootp, vnode_t *vp, char *buf, size_t buflen, int flags, 1016 cred_t *cr) 1017 { 1018 pathname_t pn, rpn, emptypn; 1019 vnode_t *cmpvp, *pvp = NULL; 1020 vnode_t *startvp = vp; 1021 int err = 0, vprivs; 1022 size_t complen; 1023 char *dbuf; 1024 dirent64_t *dp; 1025 char *bufloc; 1026 size_t dlen = DIRENT64_RECLEN(MAXPATHLEN); 1027 refstr_t *mntpt; 1028 1029 /* Operation only allowed on directories */ 1030 ASSERT(vp->v_type == VDIR); 1031 1032 /* We must have at least enough space for "/" */ 1033 if (buflen < 2) 1034 return (ENAMETOOLONG); 1035 1036 /* Start at end of string with terminating null */ 1037 bufloc = &buf[buflen - 1]; 1038 *bufloc = '\0'; 1039 1040 pn_alloc(&pn); 1041 pn_alloc(&rpn); 1042 dbuf = kmem_alloc(dlen, KM_SLEEP); 1043 bzero(&emptypn, sizeof (emptypn)); 1044 1045 /* 1046 * Begin with an additional reference on vp. This will be decremented 1047 * during the loop. 1048 */ 1049 VN_HOLD(vp); 1050 1051 for (;;) { 1052 /* 1053 * Return if we've reached the root. If the buffer is empty, 1054 * return '/'. We explicitly don't use vn_compare(), since it 1055 * compares the real vnodes. A lofs mount of '/' would produce 1056 * incorrect results otherwise. 1057 */ 1058 if (VN_CMP(vrootp, vp)) { 1059 if (*bufloc == '\0') 1060 *--bufloc = '/'; 1061 break; 1062 } 1063 1064 /* 1065 * If we've reached the VFS root, something has gone wrong. We 1066 * should have reached the root in the above check. The only 1067 * explantation is that 'vp' is not contained withing the given 1068 * root, in which case we return EPERM. 1069 */ 1070 if (VN_CMP(rootdir, vp)) { 1071 err = EPERM; 1072 goto out; 1073 } 1074 1075 /* 1076 * Shortcut: see if this vnode is a mountpoint. If so, 1077 * grab the path information from the vfs_t. 1078 */ 1079 if (vp->v_flag & VROOT) { 1080 1081 mntpt = vfs_getmntpoint(vp->v_vfsp); 1082 if ((err = pn_set(&pn, (char *)refstr_value(mntpt))) 1083 == 0) { 1084 refstr_rele(mntpt); 1085 rpn.pn_path = rpn.pn_buf; 1086 1087 /* 1088 * Ensure the mountpoint still exists. 1089 */ 1090 VN_HOLD(vrootp); 1091 if (vrootp != rootdir) 1092 VN_HOLD(vrootp); 1093 if (lookuppnvp(&pn, &rpn, flags, NULL, 1094 &cmpvp, vrootp, vrootp, cr) == 0) { 1095 1096 if (VN_CMP(vp, cmpvp)) { 1097 VN_RELE(cmpvp); 1098 1099 complen = strlen(rpn.pn_path); 1100 bufloc -= complen; 1101 if (bufloc < buf) { 1102 err = ERANGE; 1103 goto out; 1104 } 1105 bcopy(rpn.pn_path, bufloc, 1106 complen); 1107 break; 1108 } else { 1109 VN_RELE(cmpvp); 1110 } 1111 } 1112 } else { 1113 refstr_rele(mntpt); 1114 } 1115 } 1116 1117 /* 1118 * Shortcut: see if this vnode has correct v_path. If so, 1119 * we have the work done. 1120 */ 1121 mutex_enter(&vp->v_lock); 1122 if (vp->v_path != NULL) { 1123 1124 if ((err = pn_set(&pn, vp->v_path)) == 0) { 1125 mutex_exit(&vp->v_lock); 1126 rpn.pn_path = rpn.pn_buf; 1127 1128 /* 1129 * Ensure the v_path pointing to correct vnode 1130 */ 1131 VN_HOLD(vrootp); 1132 if (vrootp != rootdir) 1133 VN_HOLD(vrootp); 1134 if (lookuppnvp(&pn, &rpn, flags, NULL, 1135 &cmpvp, vrootp, vrootp, cr) == 0) { 1136 1137 if (VN_CMP(vp, cmpvp)) { 1138 VN_RELE(cmpvp); 1139 1140 complen = strlen(rpn.pn_path); 1141 bufloc -= complen; 1142 if (bufloc < buf) { 1143 err = ERANGE; 1144 goto out; 1145 } 1146 bcopy(rpn.pn_path, bufloc, 1147 complen); 1148 break; 1149 } else { 1150 VN_RELE(cmpvp); 1151 } 1152 } 1153 } else { 1154 mutex_exit(&vp->v_lock); 1155 } 1156 } else { 1157 mutex_exit(&vp->v_lock); 1158 } 1159 1160 /* 1161 * Shortcuts failed, search for this vnode in its parent. If 1162 * this is a mountpoint, then get the vnode underneath. 1163 */ 1164 if (vp->v_flag & VROOT) 1165 vp = vn_under(vp); 1166 if ((err = VOP_LOOKUP(vp, "..", &pvp, &emptypn, 0, vrootp, cr, 1167 NULL, NULL, NULL)) != 0) 1168 goto out; 1169 1170 /* 1171 * With extended attributes, it's possible for a directory to 1172 * have a parent that is a regular file. Check for that here. 1173 */ 1174 if (pvp->v_type != VDIR) { 1175 err = ENOTDIR; 1176 goto out; 1177 } 1178 1179 /* 1180 * If this is true, something strange has happened. This is 1181 * only true if we are the root of a filesystem, which should 1182 * have been caught by the check above. 1183 */ 1184 if (VN_CMP(pvp, vp)) { 1185 err = ENOENT; 1186 goto out; 1187 } 1188 1189 /* 1190 * Check if we have read and search privilege so, that 1191 * we can lookup the path in the directory 1192 */ 1193 vprivs = (flags & LOOKUP_CHECKREAD) ? VREAD | VEXEC : VEXEC; 1194 if ((err = VOP_ACCESS(pvp, vprivs, 0, cr, NULL)) != 0) { 1195 goto out; 1196 } 1197 1198 /* 1199 * Try to obtain the path component from dnlc cache 1200 * before searching through the directory. 1201 */ 1202 if ((cmpvp = dnlc_reverse_lookup(vp, dbuf, dlen)) != NULL) { 1203 /* 1204 * If we got parent vnode as a result, 1205 * then the answered path is correct. 1206 */ 1207 if (VN_CMP(cmpvp, pvp)) { 1208 VN_RELE(cmpvp); 1209 complen = strlen(dbuf); 1210 bufloc -= complen; 1211 if (bufloc <= buf) { 1212 err = ENAMETOOLONG; 1213 goto out; 1214 } 1215 bcopy(dbuf, bufloc, complen); 1216 1217 /* Prepend a slash to the current path */ 1218 *--bufloc = '/'; 1219 1220 /* And continue with the next component */ 1221 VN_RELE(vp); 1222 vp = pvp; 1223 pvp = NULL; 1224 continue; 1225 } else { 1226 VN_RELE(cmpvp); 1227 } 1228 } 1229 1230 /* 1231 * Search the parent directory for the entry corresponding to 1232 * this vnode. 1233 */ 1234 if ((err = dirfindvp(vrootp, pvp, vp, cr, dbuf, dlen, &dp)) 1235 != 0) 1236 goto out; 1237 complen = strlen(dp->d_name); 1238 bufloc -= complen; 1239 if (bufloc <= buf) { 1240 err = ENAMETOOLONG; 1241 goto out; 1242 } 1243 bcopy(dp->d_name, bufloc, complen); 1244 1245 /* Prepend a slash to the current path. */ 1246 *--bufloc = '/'; 1247 1248 /* And continue with the next component */ 1249 VN_RELE(vp); 1250 vp = pvp; 1251 pvp = NULL; 1252 } 1253 1254 /* 1255 * Place the path at the beginning of the buffer. 1256 */ 1257 if (bufloc != buf) 1258 ovbcopy(bufloc, buf, buflen - (bufloc - buf)); 1259 1260 /* 1261 * We got here because of invalid v_path in startvp. 1262 * Now, we have all info to fix it. 1263 * Path must not include leading slash to let vn_renamepath 1264 * pre-attach chroot'd root directory path. Also, trailing '\0' 1265 * is not counted to length. 1266 */ 1267 vn_renamepath(vrootp, startvp, &buf[1], buflen - (bufloc - buf) - 2); 1268 1269 out: 1270 /* 1271 * If the error was ESTALE and the current directory to look in 1272 * was the root for this lookup, the root for a mounted file 1273 * system, or the starting directory for lookups, then 1274 * return ENOENT instead of ESTALE. In this case, no recovery 1275 * is possible by the higher level. If ESTALE was returned for 1276 * some intermediate directory along the path, then recovery 1277 * is potentially possible and retrying from the higher level 1278 * will either correct the situation by purging stale cache 1279 * entries or eventually get back to the point where no recovery 1280 * is possible. 1281 */ 1282 if (err == ESTALE && 1283 (VN_CMP(vp, vrootp) || (vp->v_flag & VROOT) || vp == startvp)) 1284 err = ENOENT; 1285 1286 kmem_free(dbuf, dlen); 1287 VN_RELE(vp); 1288 if (pvp) 1289 VN_RELE(pvp); 1290 pn_free(&pn); 1291 pn_free(&rpn); 1292 1293 return (err); 1294 } 1295 1296 /* 1297 * The additional flag, LOOKUP_CHECKREAD, is used to enforce artificial 1298 * constraints in order to be standards compliant. For example, if we have 1299 * the cached path of '/foo/bar', and '/foo' has permissions 100 (execute 1300 * only), then we can legitimately look up the path to the current working 1301 * directory without needing read permission. Existing standards tests, 1302 * however, assume that we are determining the path by repeatedly looking up 1303 * "..". We need to keep this behavior in order to maintain backwards 1304 * compatibility. 1305 */ 1306 static int 1307 vnodetopath_common(vnode_t *vrootp, vnode_t *vp, char *buf, size_t buflen, 1308 cred_t *cr, int flags) 1309 { 1310 pathname_t pn, rpn; 1311 int ret, len; 1312 vnode_t *compvp, *pvp, *realvp; 1313 proc_t *p = curproc; 1314 char path[MAXNAMELEN]; 1315 int doclose = 0; 1316 1317 /* 1318 * If vrootp is NULL, get the root for curproc. Callers with any other 1319 * requirements should pass in a different vrootp. 1320 */ 1321 if (vrootp == NULL) { 1322 mutex_enter(&p->p_lock); 1323 if ((vrootp = PTOU(p)->u_rdir) == NULL) 1324 vrootp = rootdir; 1325 VN_HOLD(vrootp); 1326 mutex_exit(&p->p_lock); 1327 } else { 1328 VN_HOLD(vrootp); 1329 } 1330 1331 /* 1332 * This is to get around an annoying artifact of the /proc filesystem, 1333 * which is the behavior of {cwd/root}. Trying to resolve this path 1334 * will result in /proc/pid/cwd instead of whatever the real working 1335 * directory is. We can't rely on VOP_REALVP(), since that will break 1336 * lofs. The only difference between procfs and lofs is that opening 1337 * the file will return the underling vnode in the case of procfs. 1338 */ 1339 if (vp->v_type == VDIR && VOP_REALVP(vp, &realvp, NULL) == 0 && 1340 realvp != vp) { 1341 VN_HOLD(vp); 1342 if (VOP_OPEN(&vp, FREAD, cr, NULL) == 0) 1343 doclose = 1; 1344 else 1345 VN_RELE(vp); 1346 } 1347 1348 pn_alloc(&pn); 1349 1350 /* 1351 * Check to see if we have a cached path in the vnode. 1352 */ 1353 mutex_enter(&vp->v_lock); 1354 if (vp->v_path != NULL) { 1355 (void) pn_set(&pn, vp->v_path); 1356 mutex_exit(&vp->v_lock); 1357 1358 pn_alloc(&rpn); 1359 1360 /* We should only cache absolute paths */ 1361 ASSERT(pn.pn_buf[0] == '/'); 1362 1363 /* 1364 * If we are in a zone or a chroot environment, then we have to 1365 * take additional steps, since the path to the root might not 1366 * be readable with the current credentials, even though the 1367 * process can legitmately access the file. In this case, we 1368 * do the following: 1369 * 1370 * lookuppnvp() with all privileges to get the resolved path. 1371 * call localpath() to get the local portion of the path, and 1372 * continue as normal. 1373 * 1374 * If the the conversion to a local path fails, then we continue 1375 * as normal. This is a heuristic to make process object file 1376 * paths available from within a zone. Because lofs doesn't 1377 * support page operations, the vnode stored in the seg_t is 1378 * actually the underlying real vnode, not the lofs node itself. 1379 * Most of the time, the lofs path is the same as the underlying 1380 * vnode (for example, /usr/lib/libc.so.1). 1381 */ 1382 if (vrootp != rootdir) { 1383 char *local = NULL; 1384 VN_HOLD(rootdir); 1385 if (lookuppnvp(&pn, &rpn, FOLLOW, 1386 NULL, &compvp, rootdir, rootdir, kcred) == 0) { 1387 local = localpath(rpn.pn_path, vrootp, 1388 kcred); 1389 VN_RELE(compvp); 1390 } 1391 1392 /* 1393 * The original pn was changed through lookuppnvp(). 1394 * Set it to local for next validation attempt. 1395 */ 1396 if (local) { 1397 (void) pn_set(&pn, local); 1398 } else { 1399 goto notcached; 1400 } 1401 } 1402 1403 /* 1404 * We should have a local path at this point, so start the 1405 * search from the root of the current process. 1406 */ 1407 VN_HOLD(vrootp); 1408 if (vrootp != rootdir) 1409 VN_HOLD(vrootp); 1410 ret = lookuppnvp(&pn, &rpn, FOLLOW | flags, NULL, 1411 &compvp, vrootp, vrootp, cr); 1412 if (ret == 0) { 1413 /* 1414 * Check to see if the returned vnode is the same as 1415 * the one we expect. If not, give up. 1416 */ 1417 if (!vn_compare(vp, compvp) && 1418 !vnode_match(vp, compvp, cr)) { 1419 VN_RELE(compvp); 1420 goto notcached; 1421 } 1422 1423 VN_RELE(compvp); 1424 1425 /* 1426 * Return the result. 1427 */ 1428 if (buflen <= rpn.pn_pathlen) 1429 goto notcached; 1430 1431 bcopy(rpn.pn_path, buf, rpn.pn_pathlen + 1); 1432 pn_free(&pn); 1433 pn_free(&rpn); 1434 VN_RELE(vrootp); 1435 if (doclose) { 1436 (void) VOP_CLOSE(vp, FREAD, 1, 0, cr, NULL); 1437 VN_RELE(vp); 1438 } 1439 return (0); 1440 } 1441 1442 notcached: 1443 pn_free(&rpn); 1444 } else { 1445 mutex_exit(&vp->v_lock); 1446 } 1447 1448 pn_free(&pn); 1449 1450 if (vp->v_type != VDIR) { 1451 /* 1452 * If we don't have a directory, try to find it in the dnlc via 1453 * reverse lookup. Once this is found, we can use the regular 1454 * directory search to find the full path. 1455 */ 1456 if ((pvp = dnlc_reverse_lookup(vp, path, MAXNAMELEN)) != NULL) { 1457 /* 1458 * Check if we have read privilege so, that 1459 * we can lookup the path in the directory 1460 */ 1461 ret = 0; 1462 if ((flags & LOOKUP_CHECKREAD)) { 1463 ret = VOP_ACCESS(pvp, VREAD, 0, cr, NULL); 1464 } 1465 if (ret == 0) { 1466 ret = dirtopath(vrootp, pvp, buf, buflen, 1467 flags, cr); 1468 } 1469 if (ret == 0) { 1470 len = strlen(buf); 1471 if (len + strlen(path) + 1 >= buflen) { 1472 ret = ENAMETOOLONG; 1473 } else { 1474 if (buf[len - 1] != '/') 1475 buf[len++] = '/'; 1476 bcopy(path, buf + len, 1477 strlen(path) + 1); 1478 } 1479 } 1480 1481 VN_RELE(pvp); 1482 } else 1483 ret = ENOENT; 1484 } else 1485 ret = dirtopath(vrootp, vp, buf, buflen, flags, cr); 1486 1487 VN_RELE(vrootp); 1488 if (doclose) { 1489 (void) VOP_CLOSE(vp, FREAD, 1, 0, cr, NULL); 1490 VN_RELE(vp); 1491 } 1492 1493 return (ret); 1494 } 1495 1496 int 1497 vnodetopath(vnode_t *vrootp, vnode_t *vp, char *buf, size_t buflen, cred_t *cr) 1498 { 1499 return (vnodetopath_common(vrootp, vp, buf, buflen, cr, 0)); 1500 } 1501 1502 int 1503 dogetcwd(char *buf, size_t buflen) 1504 { 1505 int ret; 1506 vnode_t *vp; 1507 vnode_t *compvp; 1508 refstr_t *cwd, *oldcwd; 1509 const char *value; 1510 pathname_t rpnp, pnp; 1511 proc_t *p = curproc; 1512 1513 /* 1514 * Check to see if there is a cached version of the cwd. If so, lookup 1515 * the cached value and make sure it is the same vnode. 1516 */ 1517 mutex_enter(&p->p_lock); 1518 if ((cwd = PTOU(p)->u_cwd) != NULL) 1519 refstr_hold(cwd); 1520 vp = PTOU(p)->u_cdir; 1521 VN_HOLD(vp); 1522 mutex_exit(&p->p_lock); 1523 1524 /* 1525 * Make sure we have permission to access the current directory. 1526 */ 1527 if ((ret = VOP_ACCESS(vp, VEXEC, 0, CRED(), NULL)) != 0) { 1528 if (cwd != NULL) 1529 refstr_rele(cwd); 1530 VN_RELE(vp); 1531 return (ret); 1532 } 1533 1534 if (cwd) { 1535 value = refstr_value(cwd); 1536 if ((ret = pn_get((char *)value, UIO_SYSSPACE, &pnp)) != 0) { 1537 refstr_rele(cwd); 1538 VN_RELE(vp); 1539 return (ret); 1540 } 1541 1542 pn_alloc(&rpnp); 1543 1544 if (lookuppn(&pnp, &rpnp, NO_FOLLOW, NULL, &compvp) == 0) { 1545 1546 if (VN_CMP(vp, compvp) && 1547 strcmp(value, rpnp.pn_path) == 0) { 1548 VN_RELE(compvp); 1549 VN_RELE(vp); 1550 pn_free(&pnp); 1551 pn_free(&rpnp); 1552 if (strlen(value) + 1 > buflen) { 1553 refstr_rele(cwd); 1554 return (ENAMETOOLONG); 1555 } 1556 bcopy(value, buf, strlen(value) + 1); 1557 refstr_rele(cwd); 1558 return (0); 1559 } 1560 1561 VN_RELE(compvp); 1562 } 1563 1564 pn_free(&rpnp); 1565 pn_free(&pnp); 1566 1567 refstr_rele(cwd); 1568 } 1569 1570 ret = vnodetopath_common(NULL, vp, buf, buflen, CRED(), 1571 LOOKUP_CHECKREAD); 1572 1573 VN_RELE(vp); 1574 1575 /* 1576 * Store the new cwd and replace the existing cached copy. 1577 */ 1578 if (ret == 0) 1579 cwd = refstr_alloc(buf); 1580 else 1581 cwd = NULL; 1582 1583 mutex_enter(&p->p_lock); 1584 oldcwd = PTOU(p)->u_cwd; 1585 PTOU(p)->u_cwd = cwd; 1586 mutex_exit(&p->p_lock); 1587 1588 if (oldcwd) 1589 refstr_rele(oldcwd); 1590 1591 return (ret); 1592 } 1593