1 /* $NetBSD: vfs_lookup.c,v 1.15 1995/03/08 01:20:50 cgd Exp $ */ 2 3 /* 4 * Copyright (c) 1982, 1986, 1989, 1993 5 * The Regents of the University of California. All rights reserved. 6 * (c) UNIX System Laboratories, Inc. 7 * All or some portions of this file are derived from material licensed 8 * to the University of California by American Telephone and Telegraph 9 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 10 * the permission of UNIX System Laboratories, Inc. 11 * 12 * Redistribution and use in source and binary forms, with or without 13 * modification, are permitted provided that the following conditions 14 * are met: 15 * 1. Redistributions of source code must retain the above copyright 16 * notice, this list of conditions and the following disclaimer. 17 * 2. Redistributions in binary form must reproduce the above copyright 18 * notice, this list of conditions and the following disclaimer in the 19 * documentation and/or other materials provided with the distribution. 20 * 3. All advertising materials mentioning features or use of this software 21 * must display the following acknowledgement: 22 * This product includes software developed by the University of 23 * California, Berkeley and its contributors. 24 * 4. Neither the name of the University nor the names of its contributors 25 * may be used to endorse or promote products derived from this software 26 * without specific prior written permission. 27 * 28 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 29 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 30 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 31 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 32 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 33 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 34 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 35 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 36 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 37 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 38 * SUCH DAMAGE. 39 * 40 * @(#)vfs_lookup.c 8.6 (Berkeley) 11/21/94 41 */ 42 43 #include <sys/param.h> 44 #include <sys/systm.h> 45 #include <sys/syslimits.h> 46 #include <sys/time.h> 47 #include <sys/namei.h> 48 #include <sys/vnode.h> 49 #include <sys/mount.h> 50 #include <sys/errno.h> 51 #include <sys/malloc.h> 52 #include <sys/filedesc.h> 53 #include <sys/proc.h> 54 55 #ifdef KTRACE 56 #include <sys/ktrace.h> 57 #endif 58 59 /* 60 * Convert a pathname into a pointer to a locked inode. 61 * 62 * The FOLLOW flag is set when symbolic links are to be followed 63 * when they occur at the end of the name translation process. 64 * Symbolic links are always followed for all other pathname 65 * components other than the last. 66 * 67 * The segflg defines whether the name is to be copied from user 68 * space or kernel space. 69 * 70 * Overall outline of namei: 71 * 72 * copy in name 73 * get starting directory 74 * while (!done && !error) { 75 * call lookup to search path. 76 * if symbolic link, massage name in buffer and continue 77 * } 78 */ 79 int 80 namei(ndp) 81 register struct nameidata *ndp; 82 { 83 register struct filedesc *fdp; /* pointer to file descriptor state */ 84 register char *cp; /* pointer into pathname argument */ 85 register struct vnode *dp; /* the directory we are searching */ 86 struct iovec aiov; /* uio for reading symbolic links */ 87 struct uio auio; 88 int error, linklen; 89 struct componentname *cnp = &ndp->ni_cnd; 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 MALLOC(cnp->cn_pnbuf, caddr_t, MAXPATHLEN, M_NAMEI, M_WAITOK); 108 if (ndp->ni_segflg == UIO_SYSSPACE) 109 error = copystr(ndp->ni_dirp, cnp->cn_pnbuf, 110 MAXPATHLEN, &ndp->ni_pathlen); 111 else 112 error = copyinstr(ndp->ni_dirp, cnp->cn_pnbuf, 113 MAXPATHLEN, &ndp->ni_pathlen); 114 if (error) { 115 free(cnp->cn_pnbuf, M_NAMEI); 116 ndp->ni_vp = NULL; 117 return (error); 118 } 119 ndp->ni_loopcnt = 0; 120 #ifdef KTRACE 121 if (KTRPOINT(cnp->cn_proc, KTR_NAMEI)) 122 ktrnamei(cnp->cn_proc->p_tracep, cnp->cn_pnbuf); 123 #endif 124 125 /* 126 * Get starting point for the translation. 127 */ 128 if ((ndp->ni_rootdir = fdp->fd_rdir) == NULL) 129 ndp->ni_rootdir = rootvnode; 130 dp = fdp->fd_cdir; 131 VREF(dp); 132 for (;;) { 133 /* 134 * Check if root directory should replace current directory. 135 * Done at start of translation and after symbolic link. 136 */ 137 cnp->cn_nameptr = cnp->cn_pnbuf; 138 if (*(cnp->cn_nameptr) == '/') { 139 vrele(dp); 140 while (*(cnp->cn_nameptr) == '/') { 141 cnp->cn_nameptr++; 142 ndp->ni_pathlen--; 143 } 144 dp = ndp->ni_rootdir; 145 VREF(dp); 146 } 147 ndp->ni_startdir = dp; 148 if (error = lookup(ndp)) { 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 if (error = VOP_READLINK(ndp->ni_vp, &auio, cnp->cn_cred)) { 182 if (ndp->ni_pathlen > 1) 183 free(cp, M_NAMEI); 184 break; 185 } 186 linklen = MAXPATHLEN - auio.uio_resid; 187 if (linklen + ndp->ni_pathlen >= MAXPATHLEN) { 188 if (ndp->ni_pathlen > 1) 189 free(cp, M_NAMEI); 190 error = ENAMETOOLONG; 191 break; 192 } 193 if (ndp->ni_pathlen > 1) { 194 bcopy(ndp->ni_next, cp + linklen, ndp->ni_pathlen); 195 FREE(cnp->cn_pnbuf, M_NAMEI); 196 cnp->cn_pnbuf = cp; 197 } else 198 cnp->cn_pnbuf[linklen] = '\0'; 199 ndp->ni_pathlen += linklen; 200 vput(ndp->ni_vp); 201 dp = ndp->ni_dvp; 202 } 203 FREE(cnp->cn_pnbuf, M_NAMEI); 204 vrele(ndp->ni_dvp); 205 vput(ndp->ni_vp); 206 ndp->ni_vp = NULL; 207 return (error); 208 } 209 210 /* 211 * Search a pathname. 212 * This is a very central and rather complicated routine. 213 * 214 * The pathname is pointed to by ni_ptr and is of length ni_pathlen. 215 * The starting directory is taken from ni_startdir. The pathname is 216 * descended until done, or a symbolic link is encountered. The variable 217 * ni_more is clear if the path is completed; it is set to one if a 218 * symbolic link needing interpretation is encountered. 219 * 220 * The flag argument is LOOKUP, CREATE, RENAME, or DELETE depending on 221 * whether the name is to be looked up, created, renamed, or deleted. 222 * When CREATE, RENAME, or DELETE is specified, information usable in 223 * creating, renaming, or deleting a directory entry may be calculated. 224 * If flag has LOCKPARENT or'ed into it, the parent directory is returned 225 * locked. If flag has WANTPARENT or'ed into it, the parent directory is 226 * returned unlocked. Otherwise the parent directory is not returned. If 227 * the target of the pathname exists and LOCKLEAF is or'ed into the flag 228 * the target is returned locked, otherwise it is returned unlocked. 229 * When creating or renaming and LOCKPARENT is specified, the target may not 230 * be ".". When deleting and LOCKPARENT is specified, the target may be ".". 231 * 232 * Overall outline of lookup: 233 * 234 * dirloop: 235 * identify next component of name at ndp->ni_ptr 236 * handle degenerate case where name is null string 237 * if .. and crossing mount points and on mounted filesys, find parent 238 * call VOP_LOOKUP routine for next component name 239 * directory vnode returned in ni_dvp, unlocked unless LOCKPARENT set 240 * component vnode returned in ni_vp (if it exists), locked. 241 * if result vnode is mounted on and crossing mount points, 242 * find mounted on vnode 243 * if more components of name, do next level at dirloop 244 * return the answer in ni_vp, locked if LOCKLEAF set 245 * if LOCKPARENT set, return locked parent in ni_dvp 246 * if WANTPARENT set, return unlocked parent in ni_dvp 247 */ 248 int 249 lookup(ndp) 250 register struct nameidata *ndp; 251 { 252 register char *cp; /* pointer into pathname argument */ 253 register struct vnode *dp = 0; /* the directory we are searching */ 254 struct vnode *tdp; /* saved dp */ 255 struct mount *mp; /* mount table entry */ 256 int docache; /* == 0 do not cache last component */ 257 int wantparent; /* 1 => wantparent or lockparent flag */ 258 int rdonly; /* lookup read-only flag bit */ 259 int error = 0; 260 struct componentname *cnp = &ndp->ni_cnd; 261 262 /* 263 * Setup: break out flag bits into variables. 264 */ 265 wantparent = cnp->cn_flags & (LOCKPARENT | WANTPARENT); 266 docache = (cnp->cn_flags & NOCACHE) ^ NOCACHE; 267 if (cnp->cn_nameiop == DELETE || 268 (wantparent && cnp->cn_nameiop != CREATE)) 269 docache = 0; 270 rdonly = cnp->cn_flags & RDONLY; 271 ndp->ni_dvp = NULL; 272 cnp->cn_flags &= ~ISSYMLINK; 273 dp = ndp->ni_startdir; 274 ndp->ni_startdir = NULLVP; 275 VOP_LOCK(dp); 276 277 dirloop: 278 /* 279 * Search a new directory. 280 * 281 * The cn_hash value is for use by vfs_cache. 282 * The last component of the filename is left accessible via 283 * cnp->cn_nameptr for callers that need the name. Callers needing 284 * the name set the SAVENAME flag. When done, they assume 285 * responsibility for freeing the pathname buffer. 286 */ 287 cnp->cn_consume = 0; 288 cnp->cn_hash = 0; 289 for (cp = cnp->cn_nameptr; *cp != 0 && *cp != '/'; cp++) 290 cnp->cn_hash += (unsigned char)*cp; 291 cnp->cn_namelen = cp - cnp->cn_nameptr; 292 if (cnp->cn_namelen > NAME_MAX) { 293 error = ENAMETOOLONG; 294 goto bad; 295 } 296 #ifdef NAMEI_DIAGNOSTIC 297 { char c = *cp; 298 *cp = '\0'; 299 printf("{%s}: ", cnp->cn_nameptr); 300 *cp = c; } 301 #endif 302 ndp->ni_pathlen -= cnp->cn_namelen; 303 ndp->ni_next = cp; 304 cnp->cn_flags |= MAKEENTRY; 305 if (*cp == '\0' && docache == 0) 306 cnp->cn_flags &= ~MAKEENTRY; 307 if (cnp->cn_namelen == 2 && 308 cnp->cn_nameptr[1] == '.' && cnp->cn_nameptr[0] == '.') 309 cnp->cn_flags |= ISDOTDOT; 310 else 311 cnp->cn_flags &= ~ISDOTDOT; 312 if (*ndp->ni_next == 0) 313 cnp->cn_flags |= ISLASTCN; 314 else 315 cnp->cn_flags &= ~ISLASTCN; 316 317 318 /* 319 * Check for degenerate name (e.g. / or "") 320 * which is a way of talking about a directory, 321 * e.g. like "/." or ".". 322 */ 323 if (cnp->cn_nameptr[0] == '\0') { 324 if (dp->v_type != VDIR) { 325 error = ENOTDIR; 326 goto bad; 327 } 328 if (cnp->cn_nameiop != LOOKUP) { 329 error = EISDIR; 330 goto bad; 331 } 332 if (wantparent) { 333 ndp->ni_dvp = dp; 334 VREF(dp); 335 } 336 ndp->ni_vp = dp; 337 if (!(cnp->cn_flags & (LOCKPARENT | LOCKLEAF))) 338 VOP_UNLOCK(dp); 339 if (cnp->cn_flags & SAVESTART) 340 panic("lookup: SAVESTART"); 341 return (0); 342 } 343 344 /* 345 * Handle "..": two special cases. 346 * 1. If at root directory (e.g. after chroot) 347 * or at absolute root directory 348 * then ignore it so can't get out. 349 * 2. If this vnode is the root of a mounted 350 * filesystem, then replace it with the 351 * vnode which was mounted on so we take the 352 * .. in the other file system. 353 */ 354 if (cnp->cn_flags & ISDOTDOT) { 355 for (;;) { 356 if (dp == ndp->ni_rootdir || dp == rootvnode) { 357 ndp->ni_dvp = dp; 358 ndp->ni_vp = dp; 359 VREF(dp); 360 goto nextname; 361 } 362 if ((dp->v_flag & VROOT) == 0 || 363 (cnp->cn_flags & NOCROSSMOUNT)) 364 break; 365 tdp = dp; 366 dp = dp->v_mount->mnt_vnodecovered; 367 vput(tdp); 368 VREF(dp); 369 VOP_LOCK(dp); 370 } 371 } 372 373 /* 374 * We now have a segment name to search for, and a directory to search. 375 */ 376 unionlookup: 377 ndp->ni_dvp = dp; 378 if (error = VOP_LOOKUP(dp, &ndp->ni_vp, cnp)) { 379 #ifdef DIAGNOSTIC 380 if (ndp->ni_vp != NULL) 381 panic("leaf should be empty"); 382 #endif 383 #ifdef NAMEI_DIAGNOSTIC 384 printf("not found\n"); 385 #endif 386 if ((error == ENOENT) && 387 (dp->v_flag & VROOT) && 388 (dp->v_mount->mnt_flag & MNT_UNION)) { 389 tdp = dp; 390 dp = dp->v_mount->mnt_vnodecovered; 391 vput(tdp); 392 VREF(dp); 393 VOP_LOCK(dp); 394 goto unionlookup; 395 } 396 397 if (error != EJUSTRETURN) 398 goto bad; 399 /* 400 * If creating and at end of pathname, then can consider 401 * allowing file to be created. 402 */ 403 if (rdonly || (ndp->ni_dvp->v_mount->mnt_flag & MNT_RDONLY)) { 404 error = EROFS; 405 goto bad; 406 } 407 /* 408 * We return with ni_vp NULL to indicate that the entry 409 * doesn't currently exist, leaving a pointer to the 410 * (possibly locked) directory inode in ndp->ni_dvp. 411 */ 412 if (cnp->cn_flags & SAVESTART) { 413 ndp->ni_startdir = ndp->ni_dvp; 414 VREF(ndp->ni_startdir); 415 } 416 return (0); 417 } 418 #ifdef NAMEI_DIAGNOSTIC 419 printf("found\n"); 420 #endif 421 422 /* 423 * Take into account any additional components consumed by 424 * the underlying filesystem. 425 */ 426 if (cnp->cn_consume > 0) { 427 cnp->cn_nameptr += cnp->cn_consume; 428 ndp->ni_next += cnp->cn_consume; 429 ndp->ni_pathlen -= cnp->cn_consume; 430 cnp->cn_consume = 0; 431 } 432 433 dp = ndp->ni_vp; 434 /* 435 * Check to see if the vnode has been mounted on; 436 * if so find the root of the mounted file system. 437 */ 438 while (dp->v_type == VDIR && (mp = dp->v_mountedhere) && 439 (cnp->cn_flags & NOCROSSMOUNT) == 0) { 440 if (mp->mnt_flag & MNT_MLOCK) { 441 mp->mnt_flag |= MNT_MWAIT; 442 sleep((caddr_t)mp, PVFS); 443 continue; 444 } 445 if (error = VFS_ROOT(dp->v_mountedhere, &tdp)) 446 goto bad2; 447 vput(dp); 448 ndp->ni_vp = dp = tdp; 449 } 450 451 /* 452 * Check for symbolic link 453 */ 454 if ((dp->v_type == VLNK) && 455 ((cnp->cn_flags & FOLLOW) || *ndp->ni_next == '/')) { 456 cnp->cn_flags |= ISSYMLINK; 457 return (0); 458 } 459 460 nextname: 461 /* 462 * Not a symbolic link. If more pathname, 463 * continue at next component, else return. 464 */ 465 if (*ndp->ni_next == '/') { 466 cnp->cn_nameptr = ndp->ni_next; 467 while (*cnp->cn_nameptr == '/') { 468 cnp->cn_nameptr++; 469 ndp->ni_pathlen--; 470 } 471 vrele(ndp->ni_dvp); 472 goto dirloop; 473 } 474 /* 475 * Check for read-only file systems. 476 */ 477 if (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME) { 478 /* 479 * Disallow directory write attempts on read-only 480 * file systems. 481 */ 482 if (rdonly || (dp->v_mount->mnt_flag & MNT_RDONLY) || 483 (wantparent && 484 (ndp->ni_dvp->v_mount->mnt_flag & MNT_RDONLY))) { 485 error = EROFS; 486 goto bad2; 487 } 488 } 489 if (cnp->cn_flags & SAVESTART) { 490 ndp->ni_startdir = ndp->ni_dvp; 491 VREF(ndp->ni_startdir); 492 } 493 if (!wantparent) 494 vrele(ndp->ni_dvp); 495 if ((cnp->cn_flags & LOCKLEAF) == 0) 496 VOP_UNLOCK(dp); 497 return (0); 498 499 bad2: 500 if ((cnp->cn_flags & LOCKPARENT) && *ndp->ni_next == '\0') 501 VOP_UNLOCK(ndp->ni_dvp); 502 vrele(ndp->ni_dvp); 503 bad: 504 vput(dp); 505 ndp->ni_vp = NULL; 506 return (error); 507 } 508 509 /* 510 * Reacquire a path name component. 511 */ 512 int 513 relookup(dvp, vpp, cnp) 514 struct vnode *dvp, **vpp; 515 struct componentname *cnp; 516 { 517 register struct vnode *dp = 0; /* the directory we are searching */ 518 int docache; /* == 0 do not cache last component */ 519 int wantparent; /* 1 => wantparent or lockparent flag */ 520 int rdonly; /* lookup read-only flag bit */ 521 int error = 0; 522 #ifdef NAMEI_DIAGNOSTIC 523 int newhash; /* DEBUG: check name hash */ 524 char *cp; /* DEBUG: check name ptr/len */ 525 #endif 526 527 /* 528 * Setup: break out flag bits into variables. 529 */ 530 wantparent = cnp->cn_flags & (LOCKPARENT|WANTPARENT); 531 docache = (cnp->cn_flags & NOCACHE) ^ NOCACHE; 532 if (cnp->cn_nameiop == DELETE || 533 (wantparent && cnp->cn_nameiop != CREATE)) 534 docache = 0; 535 rdonly = cnp->cn_flags & RDONLY; 536 cnp->cn_flags &= ~ISSYMLINK; 537 dp = dvp; 538 VOP_LOCK(dp); 539 540 /* dirloop: */ 541 /* 542 * Search a new directory. 543 * 544 * The cn_hash value is for use by vfs_cache. 545 * The last component of the filename is left accessible via 546 * cnp->cn_nameptr for callers that need the name. Callers needing 547 * the name set the SAVENAME flag. When done, they assume 548 * responsibility for freeing the pathname buffer. 549 */ 550 #ifdef NAMEI_DIAGNOSTIC 551 for (newhash = 0, cp = cnp->cn_nameptr; *cp != 0 && *cp != '/'; cp++) 552 newhash += (unsigned char)*cp; 553 if (newhash != cnp->cn_hash) 554 panic("relookup: bad hash"); 555 if (cnp->cn_namelen != cp - cnp->cn_nameptr) 556 panic ("relookup: bad len"); 557 if (*cp != 0) 558 panic("relookup: not last component"); 559 printf("{%s}: ", cnp->cn_nameptr); 560 #endif 561 562 /* 563 * Check for degenerate name (e.g. / or "") 564 * which is a way of talking about a directory, 565 * e.g. like "/." or ".". 566 */ 567 if (cnp->cn_nameptr[0] == '\0') { 568 if (dp->v_type != VDIR) { 569 error = ENOTDIR; 570 goto bad; 571 } 572 if (cnp->cn_nameiop != LOOKUP || wantparent) { 573 error = EISDIR; 574 goto bad; 575 } 576 if (!(cnp->cn_flags & LOCKLEAF)) 577 VOP_UNLOCK(dp); 578 *vpp = dp; 579 if (cnp->cn_flags & SAVESTART) 580 panic("lookup: SAVESTART"); 581 return (0); 582 } 583 584 if (cnp->cn_flags & ISDOTDOT) 585 panic ("relookup: lookup on dot-dot"); 586 587 /* 588 * We now have a segment name to search for, and a directory to search. 589 */ 590 if (error = VOP_LOOKUP(dp, vpp, cnp)) { 591 #ifdef DIAGNOSTIC 592 if (*vpp != NULL) 593 panic("leaf should be empty"); 594 #endif 595 if (error != EJUSTRETURN) 596 goto bad; 597 /* 598 * If creating and at end of pathname, then can consider 599 * allowing file to be created. 600 */ 601 if (rdonly || (dvp->v_mount->mnt_flag & MNT_RDONLY)) { 602 error = EROFS; 603 goto bad; 604 } 605 /* ASSERT(dvp == ndp->ni_startdir) */ 606 if (cnp->cn_flags & SAVESTART) 607 VREF(dvp); 608 /* 609 * We return with ni_vp NULL to indicate that the entry 610 * doesn't currently exist, leaving a pointer to the 611 * (possibly locked) directory inode in ndp->ni_dvp. 612 */ 613 return (0); 614 } 615 dp = *vpp; 616 617 #ifdef DIAGNOSTIC 618 /* 619 * Check for symbolic link 620 */ 621 if (dp->v_type == VLNK && (cnp->cn_flags & FOLLOW)) 622 panic ("relookup: symlink found.\n"); 623 #endif 624 625 /* 626 * Check for read-only file systems. 627 */ 628 if (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME) { 629 /* 630 * Disallow directory write attempts on read-only 631 * file systems. 632 */ 633 if (rdonly || (dp->v_mount->mnt_flag & MNT_RDONLY) || 634 (wantparent && 635 (dvp->v_mount->mnt_flag & MNT_RDONLY))) { 636 error = EROFS; 637 goto bad2; 638 } 639 } 640 /* ASSERT(dvp == ndp->ni_startdir) */ 641 if (cnp->cn_flags & SAVESTART) 642 VREF(dvp); 643 644 if (!wantparent) 645 vrele(dvp); 646 if ((cnp->cn_flags & LOCKLEAF) == 0) 647 VOP_UNLOCK(dp); 648 return (0); 649 650 bad2: 651 if ((cnp->cn_flags & LOCKPARENT) && (cnp->cn_flags & ISLASTCN)) 652 VOP_UNLOCK(dvp); 653 vrele(dvp); 654 bad: 655 vput(dp); 656 *vpp = NULL; 657 return (error); 658 } 659