vfs_lookup.c revision 69405
1/* 2 * Copyright (c) 1982, 1986, 1989, 1993 3 * The Regents of the University of California. All rights reserved. 4 * (c) UNIX System Laboratories, Inc. 5 * All or some portions of this file are derived from material licensed 6 * to the University of California by American Telephone and Telegraph 7 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 8 * the permission of UNIX System Laboratories, Inc. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the University of 21 * California, Berkeley and its contributors. 22 * 4. Neither the name of the University nor the names of its contributors 23 * may be used to endorse or promote products derived from this software 24 * without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 37 * 38 * @(#)vfs_lookup.c 8.4 (Berkeley) 2/16/94 39 * $FreeBSD: head/sys/kern/vfs_lookup.c 69405 2000-11-30 20:04:44Z alfred $ 40 */ 41 42#include "opt_ktrace.h" 43 44#include <sys/param.h> 45#include <sys/systm.h> 46#include <sys/namei.h> 47#include <sys/vnode.h> 48#include <sys/mount.h> 49#include <sys/filedesc.h> 50#include <sys/proc.h> 51 52#ifdef KTRACE 53#include <sys/ktrace.h> 54#endif 55 56#include <vm/vm_zone.h> 57 58/* 59 * Convert a pathname into a pointer to a locked inode. 60 * 61 * The FOLLOW flag is set when symbolic links are to be followed 62 * when they occur at the end of the name translation process. 63 * Symbolic links are always followed for all other pathname 64 * components other than the last. 65 * 66 * The segflg defines whether the name is to be copied from user 67 * space or kernel space. 68 * 69 * Overall outline of namei: 70 * 71 * copy in name 72 * get starting directory 73 * while (!done && !error) { 74 * call lookup to search path. 75 * if symbolic link, massage name in buffer and continue 76 * } 77 */ 78int 79namei(ndp) 80 register struct nameidata *ndp; 81{ 82 register struct filedesc *fdp; /* pointer to file descriptor state */ 83 register char *cp; /* pointer into pathname argument */ 84 register struct vnode *dp; /* the directory we are searching */ 85 struct iovec aiov; /* uio for reading symbolic links */ 86 struct uio auio; 87 int error, linklen; 88 struct componentname *cnp = &ndp->ni_cnd; 89 struct proc *p = cnp->cn_proc; 90 91 ndp->ni_cnd.cn_cred = ndp->ni_cnd.cn_proc->p_ucred; 92 KASSERT(cnp->cn_cred && cnp->cn_proc, ("namei: bad cred/proc")); 93 KASSERT((cnp->cn_nameiop & (~OPMASK)) == 0, 94 ("namei: nameiop contaminated with flags")); 95 KASSERT((cnp->cn_flags & OPMASK) == 0, 96 ("namei: flags contaminated with nameiops")); 97 fdp = cnp->cn_proc->p_fd; 98 99 /* 100 * Get a buffer for the name to be translated, and copy the 101 * name into the buffer. 102 */ 103 if ((cnp->cn_flags & HASBUF) == 0) 104 cnp->cn_pnbuf = zalloc(namei_zone); 105 if (ndp->ni_segflg == UIO_SYSSPACE) 106 error = copystr(ndp->ni_dirp, cnp->cn_pnbuf, 107 MAXPATHLEN, (size_t *)&ndp->ni_pathlen); 108 else 109 error = copyinstr(ndp->ni_dirp, cnp->cn_pnbuf, 110 MAXPATHLEN, (size_t *)&ndp->ni_pathlen); 111 112 /* 113 * Don't allow empty pathnames. 114 */ 115 if (!error && *cnp->cn_pnbuf == '\0') 116 error = ENOENT; 117 118 if (error) { 119 zfree(namei_zone, cnp->cn_pnbuf); 120 ndp->ni_vp = NULL; 121 return (error); 122 } 123 ndp->ni_loopcnt = 0; 124#ifdef KTRACE 125 if (KTRPOINT(cnp->cn_proc, KTR_NAMEI)) 126 ktrnamei(cnp->cn_proc->p_tracep, cnp->cn_pnbuf); 127#endif 128 129 /* 130 * Get starting point for the translation. 131 */ 132 ndp->ni_rootdir = fdp->fd_rdir; 133 ndp->ni_topdir = fdp->fd_jdir; 134 135 dp = fdp->fd_cdir; 136 VREF(dp); 137 for (;;) { 138 /* 139 * Check if root directory should replace current directory. 140 * Done at start of translation and after symbolic link. 141 */ 142 cnp->cn_nameptr = cnp->cn_pnbuf; 143 if (*(cnp->cn_nameptr) == '/') { 144 vrele(dp); 145 while (*(cnp->cn_nameptr) == '/') { 146 cnp->cn_nameptr++; 147 ndp->ni_pathlen--; 148 } 149 dp = ndp->ni_rootdir; 150 VREF(dp); 151 } 152 ndp->ni_startdir = dp; 153 error = lookup(ndp); 154 if (error) { 155 zfree(namei_zone, cnp->cn_pnbuf); 156 return (error); 157 } 158 /* 159 * Check for symbolic link 160 */ 161 if ((cnp->cn_flags & ISSYMLINK) == 0) { 162 if ((cnp->cn_flags & (SAVENAME | SAVESTART)) == 0) 163 zfree(namei_zone, cnp->cn_pnbuf); 164 else 165 cnp->cn_flags |= HASBUF; 166 167 if (vn_canvmio(ndp->ni_vp) == TRUE && 168 (cnp->cn_nameiop != DELETE) && 169 ((cnp->cn_flags & (NOOBJ|LOCKLEAF)) == 170 LOCKLEAF)) 171 vfs_object_create(ndp->ni_vp, 172 ndp->ni_cnd.cn_proc, 173 ndp->ni_cnd.cn_cred); 174 175 return (0); 176 } 177 if ((cnp->cn_flags & LOCKPARENT) && ndp->ni_pathlen == 1) 178 VOP_UNLOCK(ndp->ni_dvp, 0, p); 179 if (ndp->ni_loopcnt++ >= MAXSYMLINKS) { 180 error = ELOOP; 181 break; 182 } 183 if (ndp->ni_pathlen > 1) 184 cp = zalloc(namei_zone); 185 else 186 cp = cnp->cn_pnbuf; 187 aiov.iov_base = cp; 188 aiov.iov_len = MAXPATHLEN; 189 auio.uio_iov = &aiov; 190 auio.uio_iovcnt = 1; 191 auio.uio_offset = 0; 192 auio.uio_rw = UIO_READ; 193 auio.uio_segflg = UIO_SYSSPACE; 194 auio.uio_procp = (struct proc *)0; 195 auio.uio_resid = MAXPATHLEN; 196 error = VOP_READLINK(ndp->ni_vp, &auio, cnp->cn_cred); 197 if (error) { 198 if (ndp->ni_pathlen > 1) 199 zfree(namei_zone, cp); 200 break; 201 } 202 linklen = MAXPATHLEN - auio.uio_resid; 203 if (linklen + ndp->ni_pathlen >= MAXPATHLEN) { 204 if (ndp->ni_pathlen > 1) 205 zfree(namei_zone, cp); 206 error = ENAMETOOLONG; 207 break; 208 } 209 if (ndp->ni_pathlen > 1) { 210 bcopy(ndp->ni_next, cp + linklen, ndp->ni_pathlen); 211 zfree(namei_zone, cnp->cn_pnbuf); 212 cnp->cn_pnbuf = cp; 213 } else 214 cnp->cn_pnbuf[linklen] = '\0'; 215 ndp->ni_pathlen += linklen; 216 vput(ndp->ni_vp); 217 dp = ndp->ni_dvp; 218 } 219 zfree(namei_zone, cnp->cn_pnbuf); 220 vrele(ndp->ni_dvp); 221 vput(ndp->ni_vp); 222 ndp->ni_vp = NULL; 223 return (error); 224} 225 226/* 227 * Search a pathname. 228 * This is a very central and rather complicated routine. 229 * 230 * The pathname is pointed to by ni_ptr and is of length ni_pathlen. 231 * The starting directory is taken from ni_startdir. The pathname is 232 * descended until done, or a symbolic link is encountered. The variable 233 * ni_more is clear if the path is completed; it is set to one if a 234 * symbolic link needing interpretation is encountered. 235 * 236 * The flag argument is LOOKUP, CREATE, RENAME, or DELETE depending on 237 * whether the name is to be looked up, created, renamed, or deleted. 238 * When CREATE, RENAME, or DELETE is specified, information usable in 239 * creating, renaming, or deleting a directory entry may be calculated. 240 * If flag has LOCKPARENT or'ed into it, the parent directory is returned 241 * locked. If flag has WANTPARENT or'ed into it, the parent directory is 242 * returned unlocked. Otherwise the parent directory is not returned. If 243 * the target of the pathname exists and LOCKLEAF is or'ed into the flag 244 * the target is returned locked, otherwise it is returned unlocked. 245 * When creating or renaming and LOCKPARENT is specified, the target may not 246 * be ".". When deleting and LOCKPARENT is specified, the target may be ".". 247 * 248 * Overall outline of lookup: 249 * 250 * dirloop: 251 * identify next component of name at ndp->ni_ptr 252 * handle degenerate case where name is null string 253 * if .. and crossing mount points and on mounted filesys, find parent 254 * call VOP_LOOKUP routine for next component name 255 * directory vnode returned in ni_dvp, unlocked unless LOCKPARENT set 256 * component vnode returned in ni_vp (if it exists), locked. 257 * if result vnode is mounted on and crossing mount points, 258 * find mounted on vnode 259 * if more components of name, do next level at dirloop 260 * return the answer in ni_vp, locked if LOCKLEAF set 261 * if LOCKPARENT set, return locked parent in ni_dvp 262 * if WANTPARENT set, return unlocked parent in ni_dvp 263 */ 264int 265lookup(ndp) 266 register struct nameidata *ndp; 267{ 268 register char *cp; /* pointer into pathname argument */ 269 register struct vnode *dp = 0; /* the directory we are searching */ 270 struct vnode *tdp; /* saved dp */ 271 struct mount *mp; /* mount table entry */ 272 int docache; /* == 0 do not cache last component */ 273 int wantparent; /* 1 => wantparent or lockparent flag */ 274 int rdonly; /* lookup read-only flag bit */ 275 int trailing_slash; 276 int error = 0; 277 int dpunlocked = 0; /* dp has already been unlocked */ 278 struct componentname *cnp = &ndp->ni_cnd; 279 struct proc *p = cnp->cn_proc; 280 281 /* 282 * Setup: break out flag bits into variables. 283 */ 284 wantparent = cnp->cn_flags & (LOCKPARENT | WANTPARENT); 285 docache = (cnp->cn_flags & NOCACHE) ^ NOCACHE; 286 if (cnp->cn_nameiop == DELETE || 287 (wantparent && cnp->cn_nameiop != CREATE && 288 cnp->cn_nameiop != LOOKUP)) 289 docache = 0; 290 rdonly = cnp->cn_flags & RDONLY; 291 ndp->ni_dvp = NULL; 292 cnp->cn_flags &= ~ISSYMLINK; 293 dp = ndp->ni_startdir; 294 ndp->ni_startdir = NULLVP; 295 vn_lock(dp, LK_EXCLUSIVE | LK_RETRY, p); 296 297dirloop: 298 /* 299 * Search a new directory. 300 * 301 * The last component of the filename is left accessible via 302 * cnp->cn_nameptr for callers that need the name. Callers needing 303 * the name set the SAVENAME flag. When done, they assume 304 * responsibility for freeing the pathname buffer. 305 */ 306 cnp->cn_consume = 0; 307 for (cp = cnp->cn_nameptr; *cp != 0 && *cp != '/'; cp++) 308 continue; 309 cnp->cn_namelen = cp - cnp->cn_nameptr; 310 if (cnp->cn_namelen > NAME_MAX) { 311 error = ENAMETOOLONG; 312 goto bad; 313 } 314#ifdef NAMEI_DIAGNOSTIC 315 { char c = *cp; 316 *cp = '\0'; 317 printf("{%s}: ", cnp->cn_nameptr); 318 *cp = c; } 319#endif 320 ndp->ni_pathlen -= cnp->cn_namelen; 321 ndp->ni_next = cp; 322 323 /* 324 * Replace multiple slashes by a single slash and trailing slashes 325 * by a null. This must be done before VOP_LOOKUP() because some 326 * fs's don't know about trailing slashes. Remember if there were 327 * trailing slashes to handle symlinks, existing non-directories 328 * and non-existing files that won't be directories specially later. 329 */ 330 trailing_slash = 0; 331 while (*cp == '/' && (cp[1] == '/' || cp[1] == '\0')) { 332 cp++; 333 ndp->ni_pathlen--; 334 if (*cp == '\0') { 335 trailing_slash = 1; 336 *ndp->ni_next = '\0'; /* XXX for direnter() ... */ 337 } 338 } 339 ndp->ni_next = cp; 340 341 cnp->cn_flags |= MAKEENTRY; 342 if (*cp == '\0' && docache == 0) 343 cnp->cn_flags &= ~MAKEENTRY; 344 if (cnp->cn_namelen == 2 && 345 cnp->cn_nameptr[1] == '.' && cnp->cn_nameptr[0] == '.') 346 cnp->cn_flags |= ISDOTDOT; 347 else 348 cnp->cn_flags &= ~ISDOTDOT; 349 if (*ndp->ni_next == 0) 350 cnp->cn_flags |= ISLASTCN; 351 else 352 cnp->cn_flags &= ~ISLASTCN; 353 354 355 /* 356 * Check for degenerate name (e.g. / or "") 357 * which is a way of talking about a directory, 358 * e.g. like "/." or ".". 359 */ 360 if (cnp->cn_nameptr[0] == '\0') { 361 if (dp->v_type != VDIR) { 362 error = ENOTDIR; 363 goto bad; 364 } 365 if (cnp->cn_nameiop != LOOKUP) { 366 error = EISDIR; 367 goto bad; 368 } 369 if (wantparent) { 370 ndp->ni_dvp = dp; 371 VREF(dp); 372 } 373 ndp->ni_vp = dp; 374 if (!(cnp->cn_flags & (LOCKPARENT | LOCKLEAF))) 375 VOP_UNLOCK(dp, 0, p); 376 /* XXX This should probably move to the top of function. */ 377 if (cnp->cn_flags & SAVESTART) 378 panic("lookup: SAVESTART"); 379 return (0); 380 } 381 382 /* 383 * Handle "..": two special cases. 384 * 1. If at root directory (e.g. after chroot) 385 * or at absolute root directory 386 * then ignore it so can't get out. 387 * 2. If this vnode is the root of a mounted 388 * filesystem, then replace it with the 389 * vnode which was mounted on so we take the 390 * .. in the other file system. 391 * 3. If the vnode is the top directory of 392 * the jail or chroot, don't let them out. 393 */ 394 if (cnp->cn_flags & ISDOTDOT) { 395 for (;;) { 396 if (dp == ndp->ni_rootdir || 397 dp == ndp->ni_topdir || 398 dp == rootvnode) { 399 ndp->ni_dvp = dp; 400 ndp->ni_vp = dp; 401 VREF(dp); 402 goto nextname; 403 } 404 if ((dp->v_flag & VROOT) == 0 || 405 (cnp->cn_flags & NOCROSSMOUNT)) 406 break; 407 if (dp->v_mount == NULL) { /* forced unmount */ 408 error = EBADF; 409 goto bad; 410 } 411 tdp = dp; 412 dp = dp->v_mount->mnt_vnodecovered; 413 vput(tdp); 414 VREF(dp); 415 vn_lock(dp, LK_EXCLUSIVE | LK_RETRY, p); 416 } 417 } 418 419 /* 420 * We now have a segment name to search for, and a directory to search. 421 */ 422unionlookup: 423 ndp->ni_dvp = dp; 424 ndp->ni_vp = NULL; 425 cnp->cn_flags &= ~PDIRUNLOCK; 426 ASSERT_VOP_LOCKED(dp, "lookup"); 427 if ((error = VOP_LOOKUP(dp, &ndp->ni_vp, cnp)) != 0) { 428 KASSERT(ndp->ni_vp == NULL, ("leaf should be empty")); 429#ifdef NAMEI_DIAGNOSTIC 430 printf("not found\n"); 431#endif 432 if ((error == ENOENT) && 433 (dp->v_flag & VROOT) && (dp->v_mount != NULL) && 434 (dp->v_mount->mnt_flag & MNT_UNION)) { 435 tdp = dp; 436 dp = dp->v_mount->mnt_vnodecovered; 437 if (cnp->cn_flags & PDIRUNLOCK) 438 vrele(tdp); 439 else 440 vput(tdp); 441 VREF(dp); 442 vn_lock(dp, LK_EXCLUSIVE | LK_RETRY, p); 443 goto unionlookup; 444 } 445 446 if (error != EJUSTRETURN) 447 goto bad; 448 /* 449 * If creating and at end of pathname, then can consider 450 * allowing file to be created. 451 */ 452 if (rdonly) { 453 error = EROFS; 454 goto bad; 455 } 456 if (*cp == '\0' && trailing_slash && 457 !(cnp->cn_flags & WILLBEDIR)) { 458 error = ENOENT; 459 goto bad; 460 } 461 /* 462 * We return with ni_vp NULL to indicate that the entry 463 * doesn't currently exist, leaving a pointer to the 464 * (possibly locked) directory inode in ndp->ni_dvp. 465 */ 466 if (cnp->cn_flags & SAVESTART) { 467 ndp->ni_startdir = ndp->ni_dvp; 468 VREF(ndp->ni_startdir); 469 } 470 return (0); 471 } 472#ifdef NAMEI_DIAGNOSTIC 473 printf("found\n"); 474#endif 475 476 ASSERT_VOP_LOCKED(ndp->ni_vp, "lookup"); 477 478 /* 479 * Take into account any additional components consumed by 480 * the underlying filesystem. 481 */ 482 if (cnp->cn_consume > 0) { 483 cnp->cn_nameptr += cnp->cn_consume; 484 ndp->ni_next += cnp->cn_consume; 485 ndp->ni_pathlen -= cnp->cn_consume; 486 cnp->cn_consume = 0; 487 } 488 489 dp = ndp->ni_vp; 490 491 /* 492 * Check to see if the vnode has been mounted on; 493 * if so find the root of the mounted file system. 494 */ 495 while (dp->v_type == VDIR && (mp = dp->v_mountedhere) && 496 (cnp->cn_flags & NOCROSSMOUNT) == 0) { 497 if (vfs_busy(mp, 0, 0, p)) 498 continue; 499 VOP_UNLOCK(dp, 0, p); 500 error = VFS_ROOT(mp, &tdp); 501 vfs_unbusy(mp, p); 502 if (error) { 503 dpunlocked = 1; 504 goto bad2; 505 } 506 vrele(dp); 507 ndp->ni_vp = dp = tdp; 508 } 509 510 /* 511 * Check for symbolic link 512 */ 513 if ((dp->v_type == VLNK) && 514 ((cnp->cn_flags & FOLLOW) || trailing_slash || 515 *ndp->ni_next == '/')) { 516 cnp->cn_flags |= ISSYMLINK; 517 if (dp->v_mount == NULL) { 518 /* We can't know whether the directory was mounted with 519 * NOSYMFOLLOW, so we can't follow safely. */ 520 error = EBADF; 521 goto bad2; 522 } 523 if (dp->v_mount->mnt_flag & MNT_NOSYMFOLLOW) { 524 error = EACCES; 525 goto bad2; 526 } 527 return (0); 528 } 529 530 /* 531 * Check for bogus trailing slashes. 532 */ 533 if (trailing_slash && dp->v_type != VDIR) { 534 error = ENOTDIR; 535 goto bad2; 536 } 537 538nextname: 539 /* 540 * Not a symbolic link. If more pathname, 541 * continue at next component, else return. 542 */ 543 if (*ndp->ni_next == '/') { 544 cnp->cn_nameptr = ndp->ni_next; 545 while (*cnp->cn_nameptr == '/') { 546 cnp->cn_nameptr++; 547 ndp->ni_pathlen--; 548 } 549 if (ndp->ni_dvp != ndp->ni_vp) 550 ASSERT_VOP_UNLOCKED(ndp->ni_dvp, "lookup"); 551 vrele(ndp->ni_dvp); 552 goto dirloop; 553 } 554 /* 555 * Disallow directory write attempts on read-only file systems. 556 */ 557 if (rdonly && 558 (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME)) { 559 error = EROFS; 560 goto bad2; 561 } 562 if (cnp->cn_flags & SAVESTART) { 563 ndp->ni_startdir = ndp->ni_dvp; 564 VREF(ndp->ni_startdir); 565 } 566 if (!wantparent) 567 vrele(ndp->ni_dvp); 568 569 if ((cnp->cn_flags & LOCKLEAF) == 0) 570 VOP_UNLOCK(dp, 0, p); 571 return (0); 572 573bad2: 574 if ((cnp->cn_flags & (LOCKPARENT | PDIRUNLOCK)) == LOCKPARENT && 575 *ndp->ni_next == '\0') 576 VOP_UNLOCK(ndp->ni_dvp, 0, p); 577 vrele(ndp->ni_dvp); 578bad: 579 if (dpunlocked) 580 vrele(dp); 581 else 582 vput(dp); 583 ndp->ni_vp = NULL; 584 return (error); 585} 586 587/* 588 * relookup - lookup a path name component 589 * Used by lookup to re-aquire things. 590 */ 591int 592relookup(dvp, vpp, cnp) 593 struct vnode *dvp, **vpp; 594 struct componentname *cnp; 595{ 596 struct proc *p = cnp->cn_proc; 597 struct vnode *dp = 0; /* the directory we are searching */ 598 int docache; /* == 0 do not cache last component */ 599 int wantparent; /* 1 => wantparent or lockparent flag */ 600 int rdonly; /* lookup read-only flag bit */ 601 int error = 0; 602#ifdef NAMEI_DIAGNOSTIC 603 int newhash; /* DEBUG: check name hash */ 604 char *cp; /* DEBUG: check name ptr/len */ 605#endif 606 607 /* 608 * Setup: break out flag bits into variables. 609 */ 610 wantparent = cnp->cn_flags & (LOCKPARENT|WANTPARENT); 611 docache = (cnp->cn_flags & NOCACHE) ^ NOCACHE; 612 if (cnp->cn_nameiop == DELETE || 613 (wantparent && cnp->cn_nameiop != CREATE)) 614 docache = 0; 615 rdonly = cnp->cn_flags & RDONLY; 616 cnp->cn_flags &= ~ISSYMLINK; 617 dp = dvp; 618 vn_lock(dp, LK_EXCLUSIVE | LK_RETRY, p); 619 620/* dirloop: */ 621 /* 622 * Search a new directory. 623 * 624 * The last component of the filename is left accessible via 625 * cnp->cn_nameptr for callers that need the name. Callers needing 626 * the name set the SAVENAME flag. When done, they assume 627 * responsibility for freeing the pathname buffer. 628 */ 629#ifdef NAMEI_DIAGNOSTIC 630 if (cnp->cn_namelen != cp - cnp->cn_nameptr) 631 panic ("relookup: bad len"); 632 if (*cp != 0) 633 panic("relookup: not last component"); 634 printf("{%s}: ", cnp->cn_nameptr); 635#endif 636 637 /* 638 * Check for degenerate name (e.g. / or "") 639 * which is a way of talking about a directory, 640 * e.g. like "/." or ".". 641 */ 642 if (cnp->cn_nameptr[0] == '\0') { 643 if (cnp->cn_nameiop != LOOKUP || wantparent) { 644 error = EISDIR; 645 goto bad; 646 } 647 if (dp->v_type != VDIR) { 648 error = ENOTDIR; 649 goto bad; 650 } 651 if (!(cnp->cn_flags & LOCKLEAF)) 652 VOP_UNLOCK(dp, 0, p); 653 *vpp = dp; 654 /* XXX This should probably move to the top of function. */ 655 if (cnp->cn_flags & SAVESTART) 656 panic("lookup: SAVESTART"); 657 return (0); 658 } 659 660 if (cnp->cn_flags & ISDOTDOT) 661 panic ("relookup: lookup on dot-dot"); 662 663 /* 664 * We now have a segment name to search for, and a directory to search. 665 */ 666 if ((error = VOP_LOOKUP(dp, vpp, cnp)) != 0) { 667 KASSERT(*vpp == NULL, ("leaf should be empty")); 668 if (error != EJUSTRETURN) 669 goto bad; 670 /* 671 * If creating and at end of pathname, then can consider 672 * allowing file to be created. 673 */ 674 if (rdonly) { 675 error = EROFS; 676 goto bad; 677 } 678 /* ASSERT(dvp == ndp->ni_startdir) */ 679 if (cnp->cn_flags & SAVESTART) 680 VREF(dvp); 681 /* 682 * We return with ni_vp NULL to indicate that the entry 683 * doesn't currently exist, leaving a pointer to the 684 * (possibly locked) directory inode in ndp->ni_dvp. 685 */ 686 return (0); 687 } 688 dp = *vpp; 689 690 /* 691 * Check for symbolic link 692 */ 693 KASSERT(dp->v_type != VLNK || !(cnp->cn_flags & FOLLOW), 694 ("relookup: symlink found.\n")); 695 696 /* 697 * Disallow directory write attempts on read-only file systems. 698 */ 699 if (rdonly && 700 (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME)) { 701 error = EROFS; 702 goto bad2; 703 } 704 /* ASSERT(dvp == ndp->ni_startdir) */ 705 if (cnp->cn_flags & SAVESTART) 706 VREF(dvp); 707 708 if (!wantparent) 709 vrele(dvp); 710 711 if (vn_canvmio(dp) == TRUE && 712 ((cnp->cn_flags & (NOOBJ|LOCKLEAF)) == LOCKLEAF)) 713 vfs_object_create(dp, cnp->cn_proc, cnp->cn_cred); 714 715 if ((cnp->cn_flags & LOCKLEAF) == 0) 716 VOP_UNLOCK(dp, 0, p); 717 return (0); 718 719bad2: 720 if ((cnp->cn_flags & LOCKPARENT) && (cnp->cn_flags & ISLASTCN)) 721 VOP_UNLOCK(dvp, 0, p); 722 vrele(dvp); 723bad: 724 vput(dp); 725 *vpp = NULL; 726 return (error); 727} 728