vfs_lookup.c revision 10219
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 1.8 1995/07/31 00:35:46 bde Exp $ 40 */ 41 42#include <sys/param.h> 43#include <sys/systm.h> 44#include <sys/syslimits.h> 45#include <sys/time.h> 46#include <sys/namei.h> 47#include <sys/vnode.h> 48#include <sys/mount.h> 49#include <sys/errno.h> 50#include <sys/malloc.h> 51#include <sys/filedesc.h> 52#include <sys/proc.h> 53 54#ifdef KTRACE 55#include <sys/ktrace.h> 56#endif 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 90 ndp->ni_cnd.cn_cred = ndp->ni_cnd.cn_proc->p_ucred; 91#ifdef DIAGNOSTIC 92 if (!cnp->cn_cred || !cnp->cn_proc) 93 panic ("namei: bad cred/proc"); 94 if (cnp->cn_nameiop & (~OPMASK)) 95 panic ("namei: nameiop contaminated with flags"); 96 if (cnp->cn_flags & OPMASK) 97 panic ("namei: flags contaminated with nameiops"); 98#endif 99 fdp = cnp->cn_proc->p_fd; 100 101 /* 102 * Get a buffer for the name to be translated, and copy the 103 * name into the buffer. 104 */ 105 if ((cnp->cn_flags & HASBUF) == 0) 106 MALLOC(cnp->cn_pnbuf, caddr_t, MAXPATHLEN, M_NAMEI, M_WAITOK); 107 if (ndp->ni_segflg == UIO_SYSSPACE) 108 error = copystr(ndp->ni_dirp, cnp->cn_pnbuf, 109 MAXPATHLEN, (u_int *)&ndp->ni_pathlen); 110 else 111 error = copyinstr(ndp->ni_dirp, cnp->cn_pnbuf, 112 MAXPATHLEN, (u_int *)&ndp->ni_pathlen); 113 if (error) { 114 free(cnp->cn_pnbuf, M_NAMEI); 115 ndp->ni_vp = NULL; 116 return (error); 117 } 118 ndp->ni_loopcnt = 0; 119#ifdef KTRACE 120 if (KTRPOINT(cnp->cn_proc, KTR_NAMEI)) 121 ktrnamei(cnp->cn_proc->p_tracep, cnp->cn_pnbuf); 122#endif 123 124 /* 125 * Get starting point for the translation. 126 */ 127 if ((ndp->ni_rootdir = fdp->fd_rdir) == NULL) 128 ndp->ni_rootdir = rootvnode; 129 dp = fdp->fd_cdir; 130 VREF(dp); 131 for (;;) { 132 /* 133 * Check if root directory should replace current directory. 134 * Done at start of translation and after symbolic link. 135 */ 136 cnp->cn_nameptr = cnp->cn_pnbuf; 137 if (*(cnp->cn_nameptr) == '/') { 138 vrele(dp); 139 while (*(cnp->cn_nameptr) == '/') { 140 cnp->cn_nameptr++; 141 ndp->ni_pathlen--; 142 } 143 dp = ndp->ni_rootdir; 144 VREF(dp); 145 } 146 ndp->ni_startdir = dp; 147 error = lookup(ndp); 148 if (error) { 149 FREE(cnp->cn_pnbuf, M_NAMEI); 150 return (error); 151 } 152 /* 153 * Check for symbolic link 154 */ 155 if ((cnp->cn_flags & ISSYMLINK) == 0) { 156 if ((cnp->cn_flags & (SAVENAME | SAVESTART)) == 0) 157 FREE(cnp->cn_pnbuf, M_NAMEI); 158 else 159 cnp->cn_flags |= HASBUF; 160 return (0); 161 } 162 if ((cnp->cn_flags & LOCKPARENT) && ndp->ni_pathlen == 1) 163 VOP_UNLOCK(ndp->ni_dvp); 164 if (ndp->ni_loopcnt++ >= MAXSYMLINKS) { 165 error = ELOOP; 166 break; 167 } 168 if (ndp->ni_pathlen > 1) 169 MALLOC(cp, char *, MAXPATHLEN, M_NAMEI, M_WAITOK); 170 else 171 cp = cnp->cn_pnbuf; 172 aiov.iov_base = cp; 173 aiov.iov_len = MAXPATHLEN; 174 auio.uio_iov = &aiov; 175 auio.uio_iovcnt = 1; 176 auio.uio_offset = 0; 177 auio.uio_rw = UIO_READ; 178 auio.uio_segflg = UIO_SYSSPACE; 179 auio.uio_procp = (struct proc *)0; 180 auio.uio_resid = MAXPATHLEN; 181 error = VOP_READLINK(ndp->ni_vp, &auio, cnp->cn_cred); 182 if (error) { 183 if (ndp->ni_pathlen > 1) 184 free(cp, M_NAMEI); 185 break; 186 } 187 linklen = MAXPATHLEN - auio.uio_resid; 188 if (linklen + ndp->ni_pathlen >= MAXPATHLEN) { 189 if (ndp->ni_pathlen > 1) 190 free(cp, M_NAMEI); 191 error = ENAMETOOLONG; 192 break; 193 } 194 if (ndp->ni_pathlen > 1) { 195 bcopy(ndp->ni_next, cp + linklen, ndp->ni_pathlen); 196 FREE(cnp->cn_pnbuf, M_NAMEI); 197 cnp->cn_pnbuf = cp; 198 } else 199 cnp->cn_pnbuf[linklen] = '\0'; 200 ndp->ni_pathlen += linklen; 201 vput(ndp->ni_vp); 202 dp = ndp->ni_dvp; 203 } 204 FREE(cnp->cn_pnbuf, M_NAMEI); 205 vrele(ndp->ni_dvp); 206 vput(ndp->ni_vp); 207 ndp->ni_vp = NULL; 208 return (error); 209} 210 211/* 212 * Search a pathname. 213 * This is a very central and rather complicated routine. 214 * 215 * The pathname is pointed to by ni_ptr and is of length ni_pathlen. 216 * The starting directory is taken from ni_startdir. The pathname is 217 * descended until done, or a symbolic link is encountered. The variable 218 * ni_more is clear if the path is completed; it is set to one if a 219 * symbolic link needing interpretation is encountered. 220 * 221 * The flag argument is LOOKUP, CREATE, RENAME, or DELETE depending on 222 * whether the name is to be looked up, created, renamed, or deleted. 223 * When CREATE, RENAME, or DELETE is specified, information usable in 224 * creating, renaming, or deleting a directory entry may be calculated. 225 * If flag has LOCKPARENT or'ed into it, the parent directory is returned 226 * locked. If flag has WANTPARENT or'ed into it, the parent directory is 227 * returned unlocked. Otherwise the parent directory is not returned. If 228 * the target of the pathname exists and LOCKLEAF is or'ed into the flag 229 * the target is returned locked, otherwise it is returned unlocked. 230 * When creating or renaming and LOCKPARENT is specified, the target may not 231 * be ".". When deleting and LOCKPARENT is specified, the target may be ".". 232 * 233 * Overall outline of lookup: 234 * 235 * dirloop: 236 * identify next component of name at ndp->ni_ptr 237 * handle degenerate case where name is null string 238 * if .. and crossing mount points and on mounted filesys, find parent 239 * call VOP_LOOKUP routine for next component name 240 * directory vnode returned in ni_dvp, unlocked unless LOCKPARENT set 241 * component vnode returned in ni_vp (if it exists), locked. 242 * if result vnode is mounted on and crossing mount points, 243 * find mounted on vnode 244 * if more components of name, do next level at dirloop 245 * return the answer in ni_vp, locked if LOCKLEAF set 246 * if LOCKPARENT set, return locked parent in ni_dvp 247 * if WANTPARENT set, return unlocked parent in ni_dvp 248 */ 249int 250lookup(ndp) 251 register struct nameidata *ndp; 252{ 253 register char *cp; /* pointer into pathname argument */ 254 register struct vnode *dp = 0; /* the directory we are searching */ 255 struct vnode *tdp; /* saved dp */ 256 struct mount *mp; /* mount table entry */ 257 int docache; /* == 0 do not cache last component */ 258 int wantparent; /* 1 => wantparent or lockparent flag */ 259 int rdonly; /* lookup read-only flag bit */ 260 int trailing_slash; 261 int error = 0; 262 struct componentname *cnp = &ndp->ni_cnd; 263 264 /* 265 * Setup: break out flag bits into variables. 266 */ 267 wantparent = cnp->cn_flags & (LOCKPARENT | WANTPARENT); 268 docache = (cnp->cn_flags & NOCACHE) ^ NOCACHE; 269 if (cnp->cn_nameiop == DELETE || 270 (wantparent && cnp->cn_nameiop != CREATE)) 271 docache = 0; 272 rdonly = cnp->cn_flags & RDONLY; 273 ndp->ni_dvp = NULL; 274 cnp->cn_flags &= ~ISSYMLINK; 275 dp = ndp->ni_startdir; 276 ndp->ni_startdir = NULLVP; 277 VOP_LOCK(dp); 278 279dirloop: 280 /* 281 * Search a new directory. 282 * 283 * The cn_hash value is for use by vfs_cache. 284 * The last component of the filename is left accessible via 285 * cnp->cn_nameptr for callers that need the name. Callers needing 286 * the name set the SAVENAME flag. When done, they assume 287 * responsibility for freeing the pathname buffer. 288 */ 289 cnp->cn_consume = 0; 290 cnp->cn_hash = 0; 291 for (cp = cnp->cn_nameptr; *cp != 0 && *cp != '/'; cp++) 292 cnp->cn_hash += (unsigned char)*cp; 293 cnp->cn_namelen = cp - cnp->cn_nameptr; 294 if (cnp->cn_namelen > NAME_MAX) { 295 error = ENAMETOOLONG; 296 goto bad; 297 } 298#ifdef NAMEI_DIAGNOSTIC 299 { char c = *cp; 300 *cp = '\0'; 301 printf("{%s}: ", cnp->cn_nameptr); 302 *cp = c; } 303#endif 304 ndp->ni_pathlen -= cnp->cn_namelen; 305 ndp->ni_next = cp; 306 307 /* 308 * Replace multiple slashes by a single slash and trailing slashes 309 * by a null. This must be done before VOP_LOOKUP() because some 310 * fs's don't know about trailing slashes. Remember if there were 311 * trailing slashes to handle symlinks, existing non-directories 312 * and non-existing files that won't be directories specially later. 313 */ 314 trailing_slash = 0; 315 while (*cp == '/' && (cp[1] == '/' || cp[1] == '\0')) { 316 cp++; 317 ndp->ni_pathlen--; 318 if (*cp == '\0') { 319 trailing_slash = 1; 320 *ndp->ni_next = '\0'; /* XXX for direnter() ... */ 321 } 322 } 323 ndp->ni_next = cp; 324 325 cnp->cn_flags |= MAKEENTRY; 326 if (*cp == '\0' && docache == 0) 327 cnp->cn_flags &= ~MAKEENTRY; 328 if (cnp->cn_namelen == 2 && 329 cnp->cn_nameptr[1] == '.' && cnp->cn_nameptr[0] == '.') 330 cnp->cn_flags |= ISDOTDOT; 331 else 332 cnp->cn_flags &= ~ISDOTDOT; 333 if (*ndp->ni_next == 0) 334 cnp->cn_flags |= ISLASTCN; 335 else 336 cnp->cn_flags &= ~ISLASTCN; 337 338 339 /* 340 * Check for degenerate name (e.g. / or "") 341 * which is a way of talking about a directory, 342 * e.g. like "/." or ".". 343 */ 344 if (cnp->cn_nameptr[0] == '\0') { 345 if (cnp->cn_nameiop != LOOKUP) { 346 error = EISDIR; 347 goto bad; 348 } 349 if (dp->v_type != VDIR) { 350 error = ENOTDIR; 351 goto bad; 352 } 353 if (wantparent) { 354 ndp->ni_dvp = dp; 355 VREF(dp); 356 } 357 ndp->ni_vp = dp; 358 if (!(cnp->cn_flags & (LOCKPARENT | LOCKLEAF))) 359 VOP_UNLOCK(dp); 360 if (cnp->cn_flags & SAVESTART) 361 panic("lookup: SAVESTART"); 362 return (0); 363 } 364 365 /* 366 * Handle "..": two special cases. 367 * 1. If at root directory (e.g. after chroot) 368 * or at absolute root directory 369 * then ignore it so can't get out. 370 * 2. If this vnode is the root of a mounted 371 * filesystem, then replace it with the 372 * vnode which was mounted on so we take the 373 * .. in the other file system. 374 */ 375 if (cnp->cn_flags & ISDOTDOT) { 376 for (;;) { 377 if (dp == ndp->ni_rootdir || dp == rootvnode) { 378 ndp->ni_dvp = dp; 379 ndp->ni_vp = dp; 380 VREF(dp); 381 goto nextname; 382 } 383 if ((dp->v_flag & VROOT) == 0 || 384 (cnp->cn_flags & NOCROSSMOUNT)) 385 break; 386 tdp = dp; 387 dp = dp->v_mount->mnt_vnodecovered; 388 vput(tdp); 389 VREF(dp); 390 VOP_LOCK(dp); 391 } 392 } 393 394 /* 395 * We now have a segment name to search for, and a directory to search. 396 */ 397unionlookup: 398 ndp->ni_dvp = dp; 399 error = VOP_LOOKUP(dp, &ndp->ni_vp, cnp); 400 if (error) { 401#ifdef DIAGNOSTIC 402 if (ndp->ni_vp != NULL) 403 panic("leaf should be empty"); 404#endif 405#ifdef NAMEI_DIAGNOSTIC 406 printf("not found\n"); 407#endif 408 if ((error == ENOENT) && 409 (dp->v_flag & VROOT) && 410 (dp->v_mount->mnt_flag & MNT_UNION)) { 411 tdp = dp; 412 dp = dp->v_mount->mnt_vnodecovered; 413 vput(tdp); 414 VREF(dp); 415 VOP_LOCK(dp); 416 goto unionlookup; 417 } 418 419 if (error != EJUSTRETURN) 420 goto bad; 421 /* 422 * If creating and at end of pathname, then can consider 423 * allowing file to be created. 424 */ 425 if (rdonly || (ndp->ni_dvp->v_mount->mnt_flag & MNT_RDONLY)) { 426 error = EROFS; 427 goto bad; 428 } 429 if (*cp == '\0' && trailing_slash && 430 !(cnp->cn_flags & WILLBEDIR)) { 431 error = ENOENT; 432 goto bad; 433 } 434 /* 435 * We return with ni_vp NULL to indicate that the entry 436 * doesn't currently exist, leaving a pointer to the 437 * (possibly locked) directory inode in ndp->ni_dvp. 438 */ 439 if (cnp->cn_flags & SAVESTART) { 440 ndp->ni_startdir = ndp->ni_dvp; 441 VREF(ndp->ni_startdir); 442 } 443 return (0); 444 } 445#ifdef NAMEI_DIAGNOSTIC 446 printf("found\n"); 447#endif 448 449 /* 450 * Take into account any additional components consumed by 451 * the underlying filesystem. 452 */ 453 if (cnp->cn_consume > 0) { 454 cnp->cn_nameptr += cnp->cn_consume; 455 ndp->ni_next += cnp->cn_consume; 456 ndp->ni_pathlen -= cnp->cn_consume; 457 cnp->cn_consume = 0; 458 } 459 460 dp = ndp->ni_vp; 461 462 /* 463 * Check to see if the vnode has been mounted on; 464 * if so find the root of the mounted file system. 465 */ 466 while (dp->v_type == VDIR && (mp = dp->v_mountedhere) && 467 (cnp->cn_flags & NOCROSSMOUNT) == 0) { 468 if (mp->mnt_flag & MNT_MLOCK) { 469 mp->mnt_flag |= MNT_MWAIT; 470 (void) tsleep((caddr_t)mp, PVFS, "lookup", 0); 471 continue; 472 } 473 error = VFS_ROOT(dp->v_mountedhere, &tdp); 474 if (error) 475 goto bad2; 476 vput(dp); 477 ndp->ni_vp = dp = tdp; 478 } 479 480 /* 481 * Check for symbolic link 482 */ 483 if ((dp->v_type == VLNK) && 484 ((cnp->cn_flags & FOLLOW) || trailing_slash || 485 *ndp->ni_next == '/')) { 486 cnp->cn_flags |= ISSYMLINK; 487 return (0); 488 } 489 490 /* 491 * Check for bogus trailing slashes. 492 */ 493 if (trailing_slash && dp->v_type != VDIR) { 494 error = ENOTDIR; 495 goto bad2; 496 } 497 498nextname: 499 /* 500 * Not a symbolic link. If more pathname, 501 * continue at next component, else return. 502 */ 503 if (*ndp->ni_next == '/') { 504 cnp->cn_nameptr = ndp->ni_next; 505 while (*cnp->cn_nameptr == '/') { 506 cnp->cn_nameptr++; 507 ndp->ni_pathlen--; 508 } 509 vrele(ndp->ni_dvp); 510 goto dirloop; 511 } 512 /* 513 * Check for read-only file systems. 514 */ 515 if (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME) { 516 /* 517 * Disallow directory write attempts on read-only 518 * file systems. 519 */ 520 if (rdonly || (dp->v_mount->mnt_flag & MNT_RDONLY) || 521 (wantparent && 522 (ndp->ni_dvp->v_mount->mnt_flag & MNT_RDONLY))) { 523 error = EROFS; 524 goto bad2; 525 } 526 } 527 if (cnp->cn_flags & SAVESTART) { 528 ndp->ni_startdir = ndp->ni_dvp; 529 VREF(ndp->ni_startdir); 530 } 531 if (!wantparent) 532 vrele(ndp->ni_dvp); 533 if ((cnp->cn_flags & LOCKLEAF) == 0) 534 VOP_UNLOCK(dp); 535 return (0); 536 537bad2: 538 if ((cnp->cn_flags & LOCKPARENT) && *ndp->ni_next == '\0') 539 VOP_UNLOCK(ndp->ni_dvp); 540 vrele(ndp->ni_dvp); 541bad: 542 vput(dp); 543 ndp->ni_vp = NULL; 544 return (error); 545} 546 547/* 548 * relookup - lookup a path name component 549 * Used by lookup to re-aquire things. 550 */ 551int 552relookup(dvp, vpp, cnp) 553 struct vnode *dvp, **vpp; 554 struct componentname *cnp; 555{ 556 register struct vnode *dp = 0; /* the directory we are searching */ 557 int docache; /* == 0 do not cache last component */ 558 int wantparent; /* 1 => wantparent or lockparent flag */ 559 int rdonly; /* lookup read-only flag bit */ 560 int error = 0; 561#ifdef NAMEI_DIAGNOSTIC 562 int newhash; /* DEBUG: check name hash */ 563 char *cp; /* DEBUG: check name ptr/len */ 564#endif 565 566 /* 567 * Setup: break out flag bits into variables. 568 */ 569 wantparent = cnp->cn_flags & (LOCKPARENT|WANTPARENT); 570 docache = (cnp->cn_flags & NOCACHE) ^ NOCACHE; 571 if (cnp->cn_nameiop == DELETE || 572 (wantparent && cnp->cn_nameiop != CREATE)) 573 docache = 0; 574 rdonly = cnp->cn_flags & RDONLY; 575 cnp->cn_flags &= ~ISSYMLINK; 576 dp = dvp; 577 VOP_LOCK(dp); 578 579/* dirloop: */ 580 /* 581 * Search a new directory. 582 * 583 * The cn_hash value is for use by vfs_cache. 584 * The last component of the filename is left accessible via 585 * cnp->cn_nameptr for callers that need the name. Callers needing 586 * the name set the SAVENAME flag. When done, they assume 587 * responsibility for freeing the pathname buffer. 588 */ 589#ifdef NAMEI_DIAGNOSTIC 590 for (newhash = 0, cp = cnp->cn_nameptr; *cp != 0 && *cp != '/'; cp++) 591 newhash += (unsigned char)*cp; 592 if (newhash != cnp->cn_hash) 593 panic("relookup: bad hash"); 594 if (cnp->cn_namelen != cp - cnp->cn_nameptr) 595 panic ("relookup: bad len"); 596 if (*cp != 0) 597 panic("relookup: not last component"); 598 printf("{%s}: ", cnp->cn_nameptr); 599#endif 600 601 /* 602 * Check for degenerate name (e.g. / or "") 603 * which is a way of talking about a directory, 604 * e.g. like "/." or ".". 605 */ 606 if (cnp->cn_nameptr[0] == '\0') { 607 if (cnp->cn_nameiop != LOOKUP || wantparent) { 608 error = EISDIR; 609 goto bad; 610 } 611 if (dp->v_type != VDIR) { 612 error = ENOTDIR; 613 goto bad; 614 } 615 if (!(cnp->cn_flags & LOCKLEAF)) 616 VOP_UNLOCK(dp); 617 *vpp = dp; 618 if (cnp->cn_flags & SAVESTART) 619 panic("lookup: SAVESTART"); 620 return (0); 621 } 622 623 if (cnp->cn_flags & ISDOTDOT) 624 panic ("relookup: lookup on dot-dot"); 625 626 /* 627 * We now have a segment name to search for, and a directory to search. 628 */ 629 error = VOP_LOOKUP(dp, vpp, cnp); 630 if (error) { 631#ifdef DIAGNOSTIC 632 if (*vpp != NULL) 633 panic("leaf should be empty"); 634#endif 635 if (error != EJUSTRETURN) 636 goto bad; 637 /* 638 * If creating and at end of pathname, then can consider 639 * allowing file to be created. 640 */ 641 if (rdonly || (dvp->v_mount->mnt_flag & MNT_RDONLY)) { 642 error = EROFS; 643 goto bad; 644 } 645 /* ASSERT(dvp == ndp->ni_startdir) */ 646 if (cnp->cn_flags & SAVESTART) 647 VREF(dvp); 648 /* 649 * We return with ni_vp NULL to indicate that the entry 650 * doesn't currently exist, leaving a pointer to the 651 * (possibly locked) directory inode in ndp->ni_dvp. 652 */ 653 return (0); 654 } 655 dp = *vpp; 656 657#ifdef DIAGNOSTIC 658 /* 659 * Check for symbolic link 660 */ 661 if (dp->v_type == VLNK && (cnp->cn_flags & FOLLOW)) 662 panic ("relookup: symlink found.\n"); 663#endif 664 665 /* 666 * Check for read-only file systems. 667 */ 668 if (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME) { 669 /* 670 * Disallow directory write attempts on read-only 671 * file systems. 672 */ 673 if (rdonly || (dp->v_mount->mnt_flag & MNT_RDONLY) || 674 (wantparent && 675 (dvp->v_mount->mnt_flag & MNT_RDONLY))) { 676 error = EROFS; 677 goto bad2; 678 } 679 } 680 /* ASSERT(dvp == ndp->ni_startdir) */ 681 if (cnp->cn_flags & SAVESTART) 682 VREF(dvp); 683 684 if (!wantparent) 685 vrele(dvp); 686 if ((cnp->cn_flags & LOCKLEAF) == 0) 687 VOP_UNLOCK(dp); 688 return (0); 689 690bad2: 691 if ((cnp->cn_flags & LOCKPARENT) && (cnp->cn_flags & ISLASTCN)) 692 VOP_UNLOCK(dvp); 693 vrele(dvp); 694bad: 695 vput(dp); 696 *vpp = NULL; 697 return (error); 698} 699