vfs_lookup.c revision 35105
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 * $Id: vfs_lookup.c,v 1.26 1998/02/15 04:17:07 dyson Exp $ 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#ifdef DIAGNOSTIC 93 if (!cnp->cn_cred || !cnp->cn_proc) 94 panic ("namei: bad cred/proc"); 95 if (cnp->cn_nameiop & (~OPMASK)) 96 panic ("namei: nameiop contaminated with flags"); 97 if (cnp->cn_flags & OPMASK) 98 panic ("namei: flags contaminated with nameiops"); 99#endif 100 fdp = cnp->cn_proc->p_fd; 101 102 /* 103 * Get a buffer for the name to be translated, and copy the 104 * name into the buffer. 105 */ 106 if ((cnp->cn_flags & HASBUF) == 0) 107 cnp->cn_pnbuf = zalloc(namei_zone); 108 if (ndp->ni_segflg == UIO_SYSSPACE) 109 error = copystr(ndp->ni_dirp, cnp->cn_pnbuf, 110 MAXPATHLEN, (u_int *)&ndp->ni_pathlen); 111 else 112 error = copyinstr(ndp->ni_dirp, cnp->cn_pnbuf, 113 MAXPATHLEN, (u_int *)&ndp->ni_pathlen); 114 115 /* 116 * Don't allow empty pathnames. 117 */ 118 if (!error && *cnp->cn_pnbuf == '\0') 119 error = ENOENT; 120 121 if (error) { 122 zfree(namei_zone, cnp->cn_pnbuf); 123 ndp->ni_vp = NULL; 124 return (error); 125 } 126 ndp->ni_loopcnt = 0; 127#ifdef KTRACE 128 if (KTRPOINT(cnp->cn_proc, KTR_NAMEI)) 129 ktrnamei(cnp->cn_proc->p_tracep, cnp->cn_pnbuf); 130#endif 131 132 /* 133 * Get starting point for the translation. 134 */ 135 ndp->ni_rootdir = fdp->fd_rdir; 136 137 dp = fdp->fd_cdir; 138 VREF(dp); 139 for (;;) { 140 /* 141 * Check if root directory should replace current directory. 142 * Done at start of translation and after symbolic link. 143 */ 144 cnp->cn_nameptr = cnp->cn_pnbuf; 145 if (*(cnp->cn_nameptr) == '/') { 146 vrele(dp); 147 while (*(cnp->cn_nameptr) == '/') { 148 cnp->cn_nameptr++; 149 ndp->ni_pathlen--; 150 } 151 dp = ndp->ni_rootdir; 152 VREF(dp); 153 } 154 ndp->ni_startdir = dp; 155 error = lookup(ndp); 156 if (error) { 157 zfree(namei_zone, cnp->cn_pnbuf); 158 return (error); 159 } 160 /* 161 * Check for symbolic link 162 */ 163 if ((cnp->cn_flags & ISSYMLINK) == 0) { 164 if ((cnp->cn_flags & (SAVENAME | SAVESTART)) == 0) 165 zfree(namei_zone, cnp->cn_pnbuf); 166 else 167 cnp->cn_flags |= HASBUF; 168 169 if (ndp->ni_vp && ndp->ni_vp->v_type == VREG && 170 (cnp->cn_nameiop != DELETE) && 171 ((cnp->cn_flags & (NOOBJ|LOCKLEAF)) == LOCKLEAF)) 172 vfs_object_create(ndp->ni_vp, 173 ndp->ni_cnd.cn_proc, ndp->ni_cnd.cn_cred, 1); 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 struct componentname *cnp = &ndp->ni_cnd; 278 struct proc *p = cnp->cn_proc; 279 280 /* 281 * Setup: break out flag bits into variables. 282 */ 283 wantparent = cnp->cn_flags & (LOCKPARENT | WANTPARENT); 284 docache = (cnp->cn_flags & NOCACHE) ^ NOCACHE; 285 if (cnp->cn_nameiop == DELETE || 286 (wantparent && cnp->cn_nameiop != CREATE && 287 cnp->cn_nameiop != LOOKUP)) 288 docache = 0; 289 rdonly = cnp->cn_flags & RDONLY; 290 ndp->ni_dvp = NULL; 291 cnp->cn_flags &= ~ISSYMLINK; 292 dp = ndp->ni_startdir; 293 ndp->ni_startdir = NULLVP; 294 vn_lock(dp, LK_EXCLUSIVE | LK_RETRY, p); 295 296dirloop: 297 /* 298 * Search a new directory. 299 * 300 * The cn_hash value is for use by vfs_cache. 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 cnp->cn_hash = 0; 308 for (cp = cnp->cn_nameptr; *cp != 0 && *cp != '/'; cp++) 309 cnp->cn_hash += (unsigned char)*cp; 310 cnp->cn_namelen = cp - cnp->cn_nameptr; 311 if (cnp->cn_namelen > NAME_MAX) { 312 error = ENAMETOOLONG; 313 goto bad; 314 } 315#ifdef NAMEI_DIAGNOSTIC 316 { char c = *cp; 317 *cp = '\0'; 318 printf("{%s}: ", cnp->cn_nameptr); 319 *cp = c; } 320#endif 321 ndp->ni_pathlen -= cnp->cn_namelen; 322 ndp->ni_next = cp; 323 324 /* 325 * Replace multiple slashes by a single slash and trailing slashes 326 * by a null. This must be done before VOP_LOOKUP() because some 327 * fs's don't know about trailing slashes. Remember if there were 328 * trailing slashes to handle symlinks, existing non-directories 329 * and non-existing files that won't be directories specially later. 330 */ 331 trailing_slash = 0; 332 while (*cp == '/' && (cp[1] == '/' || cp[1] == '\0')) { 333 cp++; 334 ndp->ni_pathlen--; 335 if (*cp == '\0') { 336 trailing_slash = 1; 337 *ndp->ni_next = '\0'; /* XXX for direnter() ... */ 338 } 339 } 340 ndp->ni_next = cp; 341 342 cnp->cn_flags |= MAKEENTRY; 343 if (*cp == '\0' && docache == 0) 344 cnp->cn_flags &= ~MAKEENTRY; 345 if (cnp->cn_namelen == 2 && 346 cnp->cn_nameptr[1] == '.' && cnp->cn_nameptr[0] == '.') 347 cnp->cn_flags |= ISDOTDOT; 348 else 349 cnp->cn_flags &= ~ISDOTDOT; 350 if (*ndp->ni_next == 0) 351 cnp->cn_flags |= ISLASTCN; 352 else 353 cnp->cn_flags &= ~ISLASTCN; 354 355 356 /* 357 * Check for degenerate name (e.g. / or "") 358 * which is a way of talking about a directory, 359 * e.g. like "/." or ".". 360 */ 361 if (cnp->cn_nameptr[0] == '\0') { 362 if (dp->v_type != VDIR) { 363 error = ENOTDIR; 364 goto bad; 365 } 366 if (cnp->cn_nameiop != LOOKUP) { 367 error = EISDIR; 368 goto bad; 369 } 370 if (wantparent) { 371 ndp->ni_dvp = dp; 372 VREF(dp); 373 } 374 ndp->ni_vp = dp; 375 if (!(cnp->cn_flags & (LOCKPARENT | LOCKLEAF))) 376 VOP_UNLOCK(dp, 0, p); 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 */ 392 if (cnp->cn_flags & ISDOTDOT) { 393 for (;;) { 394 if (dp == ndp->ni_rootdir || dp == rootvnode) { 395 ndp->ni_dvp = dp; 396 ndp->ni_vp = dp; 397 VREF(dp); 398 goto nextname; 399 } 400 if ((dp->v_flag & VROOT) == 0 || 401 (cnp->cn_flags & NOCROSSMOUNT)) 402 break; 403 tdp = dp; 404 dp = dp->v_mount->mnt_vnodecovered; 405 vput(tdp); 406 VREF(dp); 407 vn_lock(dp, LK_EXCLUSIVE | LK_RETRY, p); 408 } 409 } 410 411 /* 412 * We now have a segment name to search for, and a directory to search. 413 */ 414unionlookup: 415 ndp->ni_dvp = dp; 416 ndp->ni_vp = NULL; 417 ASSERT_VOP_LOCKED(dp, "lookup"); 418 if (error = VOP_LOOKUP(dp, &ndp->ni_vp, cnp)) { 419#ifdef DIAGNOSTIC 420 if (ndp->ni_vp != NULL) 421 panic("leaf should be empty"); 422#endif 423#ifdef NAMEI_DIAGNOSTIC 424 printf("not found\n"); 425#endif 426 if ((error == ENOENT) && 427 (dp->v_flag & VROOT) && 428 (dp->v_mount->mnt_flag & MNT_UNION)) { 429 tdp = dp; 430 dp = dp->v_mount->mnt_vnodecovered; 431 vput(tdp); 432 VREF(dp); 433 vn_lock(dp, LK_EXCLUSIVE | LK_RETRY, p); 434 goto unionlookup; 435 } 436 437 if (error != EJUSTRETURN) 438 goto bad; 439 /* 440 * If creating and at end of pathname, then can consider 441 * allowing file to be created. 442 */ 443 if (rdonly) { 444 error = EROFS; 445 goto bad; 446 } 447 if (*cp == '\0' && trailing_slash && 448 !(cnp->cn_flags & WILLBEDIR)) { 449 error = ENOENT; 450 goto bad; 451 } 452 /* 453 * We return with ni_vp NULL to indicate that the entry 454 * doesn't currently exist, leaving a pointer to the 455 * (possibly locked) directory inode in ndp->ni_dvp. 456 */ 457 if (cnp->cn_flags & SAVESTART) { 458 ndp->ni_startdir = ndp->ni_dvp; 459 VREF(ndp->ni_startdir); 460 } 461 return (0); 462 } 463#ifdef NAMEI_DIAGNOSTIC 464 printf("found\n"); 465#endif 466 467 ASSERT_VOP_LOCKED(ndp->ni_vp, "lookup"); 468 469 /* 470 * Take into account any additional components consumed by 471 * the underlying filesystem. 472 */ 473 if (cnp->cn_consume > 0) { 474 cnp->cn_nameptr += cnp->cn_consume; 475 ndp->ni_next += cnp->cn_consume; 476 ndp->ni_pathlen -= cnp->cn_consume; 477 cnp->cn_consume = 0; 478 } 479 480 dp = ndp->ni_vp; 481 482 /* 483 * Check to see if the vnode has been mounted on; 484 * if so find the root of the mounted file system. 485 */ 486 while (dp->v_type == VDIR && (mp = dp->v_mountedhere) && 487 (cnp->cn_flags & NOCROSSMOUNT) == 0) { 488 if (vfs_busy(mp, 0, 0, p)) 489 continue; 490 error = VFS_ROOT(mp, &tdp); 491 vfs_unbusy(mp, p); 492 if (error) 493 goto bad2; 494 vput(dp); 495 ndp->ni_vp = dp = tdp; 496 } 497 498 /* 499 * Check for symbolic link 500 */ 501 if ((dp->v_type == VLNK) && 502 ((cnp->cn_flags & FOLLOW) || trailing_slash || 503 *ndp->ni_next == '/')) { 504 cnp->cn_flags |= ISSYMLINK; 505 if (dp->v_mount->mnt_flag & MNT_NOSYMFOLLOW) { 506 error = EACCES; 507 goto bad2; 508 } 509 return (0); 510 } 511 512 /* 513 * Check for bogus trailing slashes. 514 */ 515 if (trailing_slash && dp->v_type != VDIR) { 516 error = ENOTDIR; 517 goto bad2; 518 } 519 520nextname: 521 /* 522 * Not a symbolic link. If more pathname, 523 * continue at next component, else return. 524 */ 525 if (*ndp->ni_next == '/') { 526 cnp->cn_nameptr = ndp->ni_next; 527 while (*cnp->cn_nameptr == '/') { 528 cnp->cn_nameptr++; 529 ndp->ni_pathlen--; 530 } 531 if (ndp->ni_dvp != ndp->ni_vp) { 532 ASSERT_VOP_UNLOCKED(ndp->ni_dvp, "lookup"); 533 } 534 vrele(ndp->ni_dvp); 535 goto dirloop; 536 } 537 /* 538 * Disallow directory write attempts on read-only file systems. 539 */ 540 if (rdonly && 541 (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME)) { 542 error = EROFS; 543 goto bad2; 544 } 545 if (cnp->cn_flags & SAVESTART) { 546 ndp->ni_startdir = ndp->ni_dvp; 547 VREF(ndp->ni_startdir); 548 } 549 if (!wantparent) 550 vrele(ndp->ni_dvp); 551 552 if ((cnp->cn_flags & LOCKLEAF) == 0) 553 VOP_UNLOCK(dp, 0, p); 554 return (0); 555 556bad2: 557 if ((cnp->cn_flags & LOCKPARENT) && *ndp->ni_next == '\0') 558 VOP_UNLOCK(ndp->ni_dvp, 0, p); 559 vrele(ndp->ni_dvp); 560bad: 561 vput(dp); 562 ndp->ni_vp = NULL; 563 return (error); 564} 565 566/* 567 * relookup - lookup a path name component 568 * Used by lookup to re-aquire things. 569 */ 570int 571relookup(dvp, vpp, cnp) 572 struct vnode *dvp, **vpp; 573 struct componentname *cnp; 574{ 575 struct proc *p = cnp->cn_proc; 576 struct vnode *dp = 0; /* the directory we are searching */ 577 int docache; /* == 0 do not cache last component */ 578 int wantparent; /* 1 => wantparent or lockparent flag */ 579 int rdonly; /* lookup read-only flag bit */ 580 int error = 0; 581#ifdef NAMEI_DIAGNOSTIC 582 int newhash; /* DEBUG: check name hash */ 583 char *cp; /* DEBUG: check name ptr/len */ 584#endif 585 586 /* 587 * Setup: break out flag bits into variables. 588 */ 589 wantparent = cnp->cn_flags & (LOCKPARENT|WANTPARENT); 590 docache = (cnp->cn_flags & NOCACHE) ^ NOCACHE; 591 if (cnp->cn_nameiop == DELETE || 592 (wantparent && cnp->cn_nameiop != CREATE)) 593 docache = 0; 594 rdonly = cnp->cn_flags & RDONLY; 595 cnp->cn_flags &= ~ISSYMLINK; 596 dp = dvp; 597 vn_lock(dp, LK_EXCLUSIVE | LK_RETRY, p); 598 599/* dirloop: */ 600 /* 601 * Search a new directory. 602 * 603 * The cn_hash value is for use by vfs_cache. 604 * The last component of the filename is left accessible via 605 * cnp->cn_nameptr for callers that need the name. Callers needing 606 * the name set the SAVENAME flag. When done, they assume 607 * responsibility for freeing the pathname buffer. 608 */ 609#ifdef NAMEI_DIAGNOSTIC 610 for (newhash = 0, cp = cnp->cn_nameptr; *cp != 0 && *cp != '/'; cp++) 611 newhash += (unsigned char)*cp; 612 if (newhash != cnp->cn_hash) 613 panic("relookup: bad hash"); 614 if (cnp->cn_namelen != cp - cnp->cn_nameptr) 615 panic ("relookup: bad len"); 616 if (*cp != 0) 617 panic("relookup: not last component"); 618 printf("{%s}: ", cnp->cn_nameptr); 619#endif 620 621 /* 622 * Check for degenerate name (e.g. / or "") 623 * which is a way of talking about a directory, 624 * e.g. like "/." or ".". 625 */ 626 if (cnp->cn_nameptr[0] == '\0') { 627 if (cnp->cn_nameiop != LOOKUP || wantparent) { 628 error = EISDIR; 629 goto bad; 630 } 631 if (dp->v_type != VDIR) { 632 error = ENOTDIR; 633 goto bad; 634 } 635 if (!(cnp->cn_flags & LOCKLEAF)) 636 VOP_UNLOCK(dp, 0, p); 637 *vpp = dp; 638 if (cnp->cn_flags & SAVESTART) 639 panic("lookup: SAVESTART"); 640 return (0); 641 } 642 643 if (cnp->cn_flags & ISDOTDOT) 644 panic ("relookup: lookup on dot-dot"); 645 646 /* 647 * We now have a segment name to search for, and a directory to search. 648 */ 649 if (error = VOP_LOOKUP(dp, vpp, cnp)) { 650#ifdef DIAGNOSTIC 651 if (*vpp != NULL) 652 panic("leaf should be empty"); 653#endif 654 if (error != EJUSTRETURN) 655 goto bad; 656 /* 657 * If creating and at end of pathname, then can consider 658 * allowing file to be created. 659 */ 660 if (rdonly) { 661 error = EROFS; 662 goto bad; 663 } 664 /* ASSERT(dvp == ndp->ni_startdir) */ 665 if (cnp->cn_flags & SAVESTART) 666 VREF(dvp); 667 /* 668 * We return with ni_vp NULL to indicate that the entry 669 * doesn't currently exist, leaving a pointer to the 670 * (possibly locked) directory inode in ndp->ni_dvp. 671 */ 672 return (0); 673 } 674 dp = *vpp; 675 676#ifdef DIAGNOSTIC 677 /* 678 * Check for symbolic link 679 */ 680 if (dp->v_type == VLNK && (cnp->cn_flags & FOLLOW)) 681 panic ("relookup: symlink found.\n"); 682#endif 683 684 /* 685 * Disallow directory write attempts on read-only file systems. 686 */ 687 if (rdonly && 688 (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME)) { 689 error = EROFS; 690 goto bad2; 691 } 692 /* ASSERT(dvp == ndp->ni_startdir) */ 693 if (cnp->cn_flags & SAVESTART) 694 VREF(dvp); 695 696 if (!wantparent) 697 vrele(dvp); 698 699 if (dp->v_type == VREG && 700 ((cnp->cn_flags & (NOOBJ|LOCKLEAF)) == LOCKLEAF)) 701 vfs_object_create(dp, cnp->cn_proc, cnp->cn_cred, 1); 702 703 if ((cnp->cn_flags & LOCKLEAF) == 0) 704 VOP_UNLOCK(dp, 0, p); 705 return (0); 706 707bad2: 708 if ((cnp->cn_flags & LOCKPARENT) && (cnp->cn_flags & ISLASTCN)) 709 VOP_UNLOCK(dvp, 0, p); 710 vrele(dvp); 711bad: 712 vput(dp); 713 *vpp = NULL; 714 return (error); 715} 716