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 1.5 1994/09/27 20:33:30 phk 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 */ 78 int 79 namei(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 */ 249 int 250 lookup(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 error = 0; 261 struct componentname *cnp = &ndp->ni_cnd; 262 263 /* 264 * Setup: break out flag bits into variables. 265 */ 266 wantparent = cnp->cn_flags & (LOCKPARENT | WANTPARENT); 267 docache = (cnp->cn_flags & NOCACHE) ^ NOCACHE; 268 if (cnp->cn_nameiop == DELETE || 269 (wantparent && cnp->cn_nameiop != CREATE)) 270 docache = 0; 271 rdonly = cnp->cn_flags & RDONLY; 272 ndp->ni_dvp = NULL; 273 cnp->cn_flags &= ~ISSYMLINK; 274 dp = ndp->ni_startdir; 275 ndp->ni_startdir = NULLVP; 276 VOP_LOCK(dp); 277 278 dirloop: 279 /* 280 * Search a new directory. 281 * 282 * The cn_hash value is for use by vfs_cache. 283 * The last component of the filename is left accessible via 284 * cnp->cn_nameptr for callers that need the name. Callers needing 285 * the name set the SAVENAME flag. When done, they assume 286 * responsibility for freeing the pathname buffer. 287 */ 288 cnp->cn_consume = 0; 289 cnp->cn_hash = 0; 290 for (cp = cnp->cn_nameptr; *cp != 0 && *cp != '/'; cp++) 291 cnp->cn_hash += (unsigned char)*cp; 292 cnp->cn_namelen = cp - cnp->cn_nameptr; 293 if (cnp->cn_namelen > NAME_MAX) { 294 error = ENAMETOOLONG; 295 goto bad; 296 } 297 #ifdef NAMEI_DIAGNOSTIC 298 { char c = *cp; 299 *cp = '\0'; 300 printf("{%s}: ", cnp->cn_nameptr); 301 *cp = c; } 302 #endif 303 ndp->ni_pathlen -= cnp->cn_namelen; 304 ndp->ni_next = cp; 305 cnp->cn_flags |= MAKEENTRY; 306 if (*cp == '\0' && docache == 0) 307 cnp->cn_flags &= ~MAKEENTRY; 308 if (cnp->cn_namelen == 2 && 309 cnp->cn_nameptr[1] == '.' && cnp->cn_nameptr[0] == '.') 310 cnp->cn_flags |= ISDOTDOT; 311 else 312 cnp->cn_flags &= ~ISDOTDOT; 313 if (*ndp->ni_next == 0) 314 cnp->cn_flags |= ISLASTCN; 315 else 316 cnp->cn_flags &= ~ISLASTCN; 317 318 319 /* 320 * Check for degenerate name (e.g. / or "") 321 * which is a way of talking about a directory, 322 * e.g. like "/." or ".". 323 */ 324 if (cnp->cn_nameptr[0] == '\0') { 325 if (cnp->cn_nameiop != LOOKUP) { 326 error = EISDIR; 327 goto bad; 328 } 329 if (dp->v_type != VDIR) { 330 error = ENOTDIR; 331 goto bad; 332 } 333 if (wantparent) { 334 ndp->ni_dvp = dp; 335 VREF(dp); 336 } 337 ndp->ni_vp = dp; 338 if (!(cnp->cn_flags & (LOCKPARENT | LOCKLEAF))) 339 VOP_UNLOCK(dp); 340 if (cnp->cn_flags & SAVESTART) 341 panic("lookup: SAVESTART"); 342 return (0); 343 } 344 345 /* 346 * Handle "..": two special cases. 347 * 1. If at root directory (e.g. after chroot) 348 * or at absolute root directory 349 * then ignore it so can't get out. 350 * 2. If this vnode is the root of a mounted 351 * filesystem, then replace it with the 352 * vnode which was mounted on so we take the 353 * .. in the other file system. 354 */ 355 if (cnp->cn_flags & ISDOTDOT) { 356 for (;;) { 357 if (dp == ndp->ni_rootdir || dp == rootvnode) { 358 ndp->ni_dvp = dp; 359 ndp->ni_vp = dp; 360 VREF(dp); 361 goto nextname; 362 } 363 if ((dp->v_flag & VROOT) == 0 || 364 (cnp->cn_flags & NOCROSSMOUNT)) 365 break; 366 tdp = dp; 367 dp = dp->v_mount->mnt_vnodecovered; 368 vput(tdp); 369 VREF(dp); 370 VOP_LOCK(dp); 371 } 372 } 373 374 /* 375 * We now have a segment name to search for, and a directory to search. 376 */ 377 unionlookup: 378 ndp->ni_dvp = dp; 379 error = VOP_LOOKUP(dp, &ndp->ni_vp, cnp); 380 if (error) { 381 #ifdef DIAGNOSTIC 382 if (ndp->ni_vp != NULL) 383 panic("leaf should be empty"); 384 #endif 385 #ifdef NAMEI_DIAGNOSTIC 386 printf("not found\n"); 387 #endif 388 if ((error == ENOENT) && 389 (dp->v_flag & VROOT) && 390 (dp->v_mount->mnt_flag & MNT_UNION)) { 391 tdp = dp; 392 dp = dp->v_mount->mnt_vnodecovered; 393 vput(tdp); 394 VREF(dp); 395 VOP_LOCK(dp); 396 goto unionlookup; 397 } 398 399 if (error != EJUSTRETURN) 400 goto bad; 401 /* 402 * If creating and at end of pathname, then can consider 403 * allowing file to be created. 404 */ 405 if (rdonly || (ndp->ni_dvp->v_mount->mnt_flag & MNT_RDONLY)) { 406 error = EROFS; 407 goto bad; 408 } 409 /* 410 * We return with ni_vp NULL to indicate that the entry 411 * doesn't currently exist, leaving a pointer to the 412 * (possibly locked) directory inode in ndp->ni_dvp. 413 */ 414 if (cnp->cn_flags & SAVESTART) { 415 ndp->ni_startdir = ndp->ni_dvp; 416 VREF(ndp->ni_startdir); 417 } 418 return (0); 419 } 420 #ifdef NAMEI_DIAGNOSTIC 421 printf("found\n"); 422 #endif 423 424 /* 425 * Take into account any additional components consumed by 426 * the underlying filesystem. 427 */ 428 if (cnp->cn_consume > 0) { 429 cnp->cn_nameptr += cnp->cn_consume; 430 ndp->ni_next += cnp->cn_consume; 431 ndp->ni_pathlen -= cnp->cn_consume; 432 cnp->cn_consume = 0; 433 } 434 435 dp = ndp->ni_vp; 436 /* 437 * Check for symbolic link 438 */ 439 if ((dp->v_type == VLNK) && 440 ((cnp->cn_flags & FOLLOW) || *ndp->ni_next == '/')) { 441 cnp->cn_flags |= ISSYMLINK; 442 return (0); 443 } 444 445 /* 446 * Check to see if the vnode has been mounted on; 447 * if so find the root of the mounted file system. 448 */ 449 while (dp->v_type == VDIR && (mp = dp->v_mountedhere) && 450 (cnp->cn_flags & NOCROSSMOUNT) == 0) { 451 if (mp->mnt_flag & MNT_MLOCK) { 452 mp->mnt_flag |= MNT_MWAIT; 453 (void) tsleep((caddr_t)mp, PVFS, "lookup", 0); 454 continue; 455 } 456 error = VFS_ROOT(dp->v_mountedhere, &tdp); 457 if (error) 458 goto bad2; 459 vput(dp); 460 ndp->ni_vp = dp = tdp; 461 } 462 463 nextname: 464 /* 465 * Not a symbolic link. If more pathname, 466 * continue at next component, else return. 467 */ 468 if (*ndp->ni_next == '/') { 469 cnp->cn_nameptr = ndp->ni_next; 470 while (*cnp->cn_nameptr == '/') { 471 cnp->cn_nameptr++; 472 ndp->ni_pathlen--; 473 } 474 vrele(ndp->ni_dvp); 475 goto dirloop; 476 } 477 /* 478 * Check for read-only file systems. 479 */ 480 if (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME) { 481 /* 482 * Disallow directory write attempts on read-only 483 * file systems. 484 */ 485 if (rdonly || (dp->v_mount->mnt_flag & MNT_RDONLY) || 486 (wantparent && 487 (ndp->ni_dvp->v_mount->mnt_flag & MNT_RDONLY))) { 488 error = EROFS; 489 goto bad2; 490 } 491 } 492 if (cnp->cn_flags & SAVESTART) { 493 ndp->ni_startdir = ndp->ni_dvp; 494 VREF(ndp->ni_startdir); 495 } 496 if (!wantparent) 497 vrele(ndp->ni_dvp); 498 if ((cnp->cn_flags & LOCKLEAF) == 0) 499 VOP_UNLOCK(dp); 500 return (0); 501 502 bad2: 503 if ((cnp->cn_flags & LOCKPARENT) && *ndp->ni_next == '\0') 504 VOP_UNLOCK(ndp->ni_dvp); 505 vrele(ndp->ni_dvp); 506 bad: 507 vput(dp); 508 ndp->ni_vp = NULL; 509 return (error); 510 } 511 512 /* 513 * relookup - lookup a path name component 514 * Used by lookup to re-aquire things. 515 */ 516 int 517 relookup(dvp, vpp, cnp) 518 struct vnode *dvp, **vpp; 519 struct componentname *cnp; 520 { 521 register struct vnode *dp = 0; /* the directory we are searching */ 522 int docache; /* == 0 do not cache last component */ 523 int wantparent; /* 1 => wantparent or lockparent flag */ 524 int rdonly; /* lookup read-only flag bit */ 525 int error = 0; 526 #ifdef NAMEI_DIAGNOSTIC 527 int newhash; /* DEBUG: check name hash */ 528 char *cp; /* DEBUG: check name ptr/len */ 529 #endif 530 531 /* 532 * Setup: break out flag bits into variables. 533 */ 534 wantparent = cnp->cn_flags & (LOCKPARENT|WANTPARENT); 535 docache = (cnp->cn_flags & NOCACHE) ^ NOCACHE; 536 if (cnp->cn_nameiop == DELETE || 537 (wantparent && cnp->cn_nameiop != CREATE)) 538 docache = 0; 539 rdonly = cnp->cn_flags & RDONLY; 540 cnp->cn_flags &= ~ISSYMLINK; 541 dp = dvp; 542 VOP_LOCK(dp); 543 544 /* dirloop: */ 545 /* 546 * Search a new directory. 547 * 548 * The cn_hash value is for use by vfs_cache. 549 * The last component of the filename is left accessible via 550 * cnp->cn_nameptr for callers that need the name. Callers needing 551 * the name set the SAVENAME flag. When done, they assume 552 * responsibility for freeing the pathname buffer. 553 */ 554 #ifdef NAMEI_DIAGNOSTIC 555 for (newhash = 0, cp = cnp->cn_nameptr; *cp != 0 && *cp != '/'; cp++) 556 newhash += (unsigned char)*cp; 557 if (newhash != cnp->cn_hash) 558 panic("relookup: bad hash"); 559 if (cnp->cn_namelen != cp - cnp->cn_nameptr) 560 panic ("relookup: bad len"); 561 if (*cp != 0) 562 panic("relookup: not last component"); 563 printf("{%s}: ", cnp->cn_nameptr); 564 #endif 565 566 /* 567 * Check for degenerate name (e.g. / or "") 568 * which is a way of talking about a directory, 569 * e.g. like "/." or ".". 570 */ 571 if (cnp->cn_nameptr[0] == '\0') { 572 if (cnp->cn_nameiop != LOOKUP || wantparent) { 573 error = EISDIR; 574 goto bad; 575 } 576 if (dp->v_type != VDIR) { 577 error = ENOTDIR; 578 goto bad; 579 } 580 if (!(cnp->cn_flags & LOCKLEAF)) 581 VOP_UNLOCK(dp); 582 *vpp = dp; 583 if (cnp->cn_flags & SAVESTART) 584 panic("lookup: SAVESTART"); 585 return (0); 586 } 587 588 if (cnp->cn_flags & ISDOTDOT) 589 panic ("relookup: lookup on dot-dot"); 590 591 /* 592 * We now have a segment name to search for, and a directory to search. 593 */ 594 error = VOP_LOOKUP(dp, vpp, cnp); 595 if (error) { 596 #ifdef DIAGNOSTIC 597 if (*vpp != NULL) 598 panic("leaf should be empty"); 599 #endif 600 if (error != EJUSTRETURN) 601 goto bad; 602 /* 603 * If creating and at end of pathname, then can consider 604 * allowing file to be created. 605 */ 606 if (rdonly || (dvp->v_mount->mnt_flag & MNT_RDONLY)) { 607 error = EROFS; 608 goto bad; 609 } 610 /* ASSERT(dvp == ndp->ni_startdir) */ 611 if (cnp->cn_flags & SAVESTART) 612 VREF(dvp); 613 /* 614 * We return with ni_vp NULL to indicate that the entry 615 * doesn't currently exist, leaving a pointer to the 616 * (possibly locked) directory inode in ndp->ni_dvp. 617 */ 618 return (0); 619 } 620 dp = *vpp; 621 622 #ifdef DIAGNOSTIC 623 /* 624 * Check for symbolic link 625 */ 626 if (dp->v_type == VLNK && (cnp->cn_flags & FOLLOW)) 627 panic ("relookup: symlink found.\n"); 628 #endif 629 630 /* 631 * Check for read-only file systems. 632 */ 633 if (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME) { 634 /* 635 * Disallow directory write attempts on read-only 636 * file systems. 637 */ 638 if (rdonly || (dp->v_mount->mnt_flag & MNT_RDONLY) || 639 (wantparent && 640 (dvp->v_mount->mnt_flag & MNT_RDONLY))) { 641 error = EROFS; 642 goto bad2; 643 } 644 } 645 /* ASSERT(dvp == ndp->ni_startdir) */ 646 if (cnp->cn_flags & SAVESTART) 647 VREF(dvp); 648 649 if (!wantparent) 650 vrele(dvp); 651 if ((cnp->cn_flags & LOCKLEAF) == 0) 652 VOP_UNLOCK(dp); 653 return (0); 654 655 bad2: 656 if ((cnp->cn_flags & LOCKPARENT) && (cnp->cn_flags & ISLASTCN)) 657 VOP_UNLOCK(dvp); 658 vrele(dvp); 659 bad: 660 vput(dp); 661 *vpp = NULL; 662 return (error); 663 } 664