vfs_lookup.c revision 1.35.2.1
1 /* $NetBSD: vfs_lookup.c,v 1.35.2.1 2001/09/21 22:36:27 nathanw 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 8.10 (Berkeley) 5/27/95 41 */ 42 43 #include "opt_ktrace.h" 44 45 #include <sys/param.h> 46 #include <sys/systm.h> 47 #include <sys/syslimits.h> 48 #include <sys/time.h> 49 #include <sys/namei.h> 50 #include <sys/vnode.h> 51 #include <sys/mount.h> 52 #include <sys/errno.h> 53 #include <sys/malloc.h> 54 #include <sys/filedesc.h> 55 #include <sys/proc.h> 56 57 #ifdef KTRACE 58 #include <sys/ktrace.h> 59 #endif 60 61 struct pool pnbuf_pool; /* pathname buffer pool */ 62 63 /* 64 * Convert a pathname into a pointer to a locked inode. 65 * 66 * The FOLLOW flag is set when symbolic links are to be followed 67 * when they occur at the end of the name translation process. 68 * Symbolic links are always followed for all other pathname 69 * components other than the last. 70 * 71 * The segflg defines whether the name is to be copied from user 72 * space or kernel space. 73 * 74 * Overall outline of namei: 75 * 76 * copy in name 77 * get starting directory 78 * while (!done && !error) { 79 * call lookup to search path. 80 * if symbolic link, massage name in buffer and continue 81 * } 82 */ 83 int 84 namei(ndp) 85 struct nameidata *ndp; 86 { 87 struct cwdinfo *cwdi; /* pointer to cwd state */ 88 char *cp; /* pointer into pathname argument */ 89 struct vnode *dp; /* the directory we are searching */ 90 struct iovec aiov; /* uio for reading symbolic links */ 91 struct uio auio; 92 int error, linklen; 93 struct componentname *cnp = &ndp->ni_cnd; 94 95 #ifdef DIAGNOSTIC 96 if (!cnp->cn_cred || !cnp->cn_proc) 97 panic ("namei: bad cred/proc"); 98 if (cnp->cn_nameiop & (~OPMASK)) 99 panic ("namei: nameiop contaminated with flags"); 100 if (cnp->cn_flags & OPMASK) 101 panic ("namei: flags contaminated with nameiops"); 102 #endif 103 cwdi = cnp->cn_proc->p_cwdi; 104 105 /* 106 * Get a buffer for the name to be translated, and copy the 107 * name into the buffer. 108 */ 109 if ((cnp->cn_flags & HASBUF) == 0) 110 cnp->cn_pnbuf = PNBUF_GET(); 111 if (ndp->ni_segflg == UIO_SYSSPACE) 112 error = copystr(ndp->ni_dirp, cnp->cn_pnbuf, 113 MAXPATHLEN, &ndp->ni_pathlen); 114 else 115 error = copyinstr(ndp->ni_dirp, cnp->cn_pnbuf, 116 MAXPATHLEN, &ndp->ni_pathlen); 117 118 /* 119 * POSIX.1 requirement: "" is not a valid file name. 120 */ 121 if (!error && ndp->ni_pathlen == 1) 122 error = ENOENT; 123 124 if (error) { 125 PNBUF_PUT(cnp->cn_pnbuf); 126 ndp->ni_vp = NULL; 127 return (error); 128 } 129 ndp->ni_loopcnt = 0; 130 131 #ifdef KTRACE 132 if (KTRPOINT(cnp->cn_proc, KTR_NAMEI)) 133 ktrnamei(cnp->cn_proc, cnp->cn_pnbuf); 134 #endif 135 136 /* 137 * Get starting point for the translation. 138 */ 139 if ((ndp->ni_rootdir = cwdi->cwdi_rdir) == NULL) 140 ndp->ni_rootdir = rootvnode; 141 /* 142 * Check if starting from root directory or current directory. 143 */ 144 if (cnp->cn_pnbuf[0] == '/') { 145 dp = ndp->ni_rootdir; 146 VREF(dp); 147 } else { 148 dp = cwdi->cwdi_cdir; 149 VREF(dp); 150 } 151 for (;;) { 152 cnp->cn_nameptr = cnp->cn_pnbuf; 153 ndp->ni_startdir = dp; 154 if ((error = lookup(ndp)) != 0) { 155 PNBUF_PUT(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 PNBUF_PUT(cnp->cn_pnbuf); 164 else 165 cnp->cn_flags |= HASBUF; 166 return (0); 167 } 168 if ((cnp->cn_flags & LOCKPARENT) && (cnp->cn_flags & ISLASTCN)) 169 VOP_UNLOCK(ndp->ni_dvp, 0); 170 if (ndp->ni_loopcnt++ >= MAXSYMLINKS) { 171 error = ELOOP; 172 break; 173 } 174 if (ndp->ni_vp->v_mount->mnt_flag & MNT_SYMPERM) { 175 error = VOP_ACCESS(ndp->ni_vp, VEXEC, cnp->cn_cred, 176 cnp->cn_proc); 177 if (error != 0) 178 break; 179 } 180 if (ndp->ni_pathlen > 1) 181 cp = PNBUF_GET(); 182 else 183 cp = cnp->cn_pnbuf; 184 aiov.iov_base = cp; 185 aiov.iov_len = MAXPATHLEN; 186 auio.uio_iov = &aiov; 187 auio.uio_iovcnt = 1; 188 auio.uio_offset = 0; 189 auio.uio_rw = UIO_READ; 190 auio.uio_segflg = UIO_SYSSPACE; 191 auio.uio_procp = (struct proc *)0; 192 auio.uio_resid = MAXPATHLEN; 193 error = VOP_READLINK(ndp->ni_vp, &auio, cnp->cn_cred); 194 if (error) { 195 badlink: 196 if (ndp->ni_pathlen > 1) 197 PNBUF_PUT(cp); 198 break; 199 } 200 linklen = MAXPATHLEN - auio.uio_resid; 201 if (linklen == 0) { 202 error = ENOENT; 203 goto badlink; 204 } 205 if (linklen + ndp->ni_pathlen >= MAXPATHLEN) { 206 error = ENAMETOOLONG; 207 goto badlink; 208 } 209 if (ndp->ni_pathlen > 1) { 210 memcpy(cp + linklen, ndp->ni_next, ndp->ni_pathlen); 211 PNBUF_PUT(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 * Check if root directory should replace current directory. 220 */ 221 if (cnp->cn_pnbuf[0] == '/') { 222 vrele(dp); 223 dp = ndp->ni_rootdir; 224 VREF(dp); 225 } 226 } 227 PNBUF_PUT(cnp->cn_pnbuf); 228 vrele(ndp->ni_dvp); 229 vput(ndp->ni_vp); 230 ndp->ni_vp = NULL; 231 return (error); 232 } 233 234 /* 235 * Search a pathname. 236 * This is a very central and rather complicated routine. 237 * 238 * The pathname is pointed to by ni_ptr and is of length ni_pathlen. 239 * The starting directory is taken from ni_startdir. The pathname is 240 * descended until done, or a symbolic link is encountered. The variable 241 * ni_more is clear if the path is completed; it is set to one if a 242 * symbolic link needing interpretation is encountered. 243 * 244 * The flag argument is LOOKUP, CREATE, RENAME, or DELETE depending on 245 * whether the name is to be looked up, created, renamed, or deleted. 246 * When CREATE, RENAME, or DELETE is specified, information usable in 247 * creating, renaming, or deleting a directory entry may be calculated. 248 * If flag has LOCKPARENT or'ed into it, the parent directory is returned 249 * locked. If flag has WANTPARENT or'ed into it, the parent directory is 250 * returned unlocked. Otherwise the parent directory is not returned. If 251 * the target of the pathname exists and LOCKLEAF is or'ed into the flag 252 * the target is returned locked, otherwise it is returned unlocked. 253 * When creating or renaming and LOCKPARENT is specified, the target may not 254 * be ".". When deleting and LOCKPARENT is specified, the target may be ".". 255 * 256 * Overall outline of lookup: 257 * 258 * dirloop: 259 * identify next component of name at ndp->ni_ptr 260 * handle degenerate case where name is null string 261 * if .. and crossing mount points and on mounted filesys, find parent 262 * call VOP_LOOKUP routine for next component name 263 * directory vnode returned in ni_dvp, unlocked unless LOCKPARENT set 264 * component vnode returned in ni_vp (if it exists), locked. 265 * if result vnode is mounted on and crossing mount points, 266 * find mounted on vnode 267 * if more components of name, do next level at dirloop 268 * return the answer in ni_vp, locked if LOCKLEAF set 269 * if LOCKPARENT set, return locked parent in ni_dvp 270 * if WANTPARENT set, return unlocked parent in ni_dvp 271 */ 272 int 273 lookup(ndp) 274 struct nameidata *ndp; 275 { 276 const char *cp; /* pointer into pathname argument */ 277 struct vnode *dp = 0; /* the directory we are searching */ 278 struct vnode *tdp; /* saved dp */ 279 struct mount *mp; /* mount table entry */ 280 int docache; /* == 0 do not cache last component */ 281 int wantparent; /* 1 => wantparent or lockparent flag */ 282 int rdonly; /* lookup read-only flag bit */ 283 int error = 0; 284 int slashes; 285 int dpunlocked = 0; /* dp has already been unlocked */ 286 struct componentname *cnp = &ndp->ni_cnd; 287 288 /* 289 * Setup: break out flag bits into variables. 290 */ 291 wantparent = cnp->cn_flags & (LOCKPARENT | WANTPARENT); 292 docache = (cnp->cn_flags & NOCACHE) ^ NOCACHE; 293 if (cnp->cn_nameiop == DELETE || 294 (wantparent && cnp->cn_nameiop != CREATE)) 295 docache = 0; 296 rdonly = cnp->cn_flags & RDONLY; 297 ndp->ni_dvp = NULL; 298 cnp->cn_flags &= ~ISSYMLINK; 299 dp = ndp->ni_startdir; 300 ndp->ni_startdir = NULLVP; 301 vn_lock(dp, LK_EXCLUSIVE | LK_RETRY); 302 303 /* 304 * If we have a leading string of slashes, remove them, and just make 305 * sure the current node is a directory. 306 */ 307 cp = cnp->cn_nameptr; 308 if (*cp == '/') { 309 do { 310 cp++; 311 } while (*cp == '/'); 312 ndp->ni_pathlen -= cp - cnp->cn_nameptr; 313 cnp->cn_nameptr = cp; 314 315 if (dp->v_type != VDIR) { 316 error = ENOTDIR; 317 goto bad; 318 } 319 320 /* 321 * If we've exhausted the path name, then just return the 322 * current node. If the caller requested the parent node (i.e. 323 * it's a CREATE, DELETE, or RENAME), and we don't have one 324 * (because this is the root directory), then we must fail. 325 */ 326 if (cnp->cn_nameptr[0] == '\0') { 327 if (ndp->ni_dvp == NULL && wantparent) { 328 error = EISDIR; 329 goto bad; 330 } 331 ndp->ni_vp = dp; 332 cnp->cn_flags |= ISLASTCN; 333 goto terminal; 334 } 335 } 336 337 dirloop: 338 /* 339 * Search a new directory. 340 * 341 * The cn_hash value is for use by vfs_cache. 342 * The last component of the filename is left accessible via 343 * cnp->cn_nameptr for callers that need the name. Callers needing 344 * the name set the SAVENAME flag. When done, they assume 345 * responsibility for freeing the pathname buffer. 346 */ 347 cnp->cn_consume = 0; 348 cnp->cn_hash = 0; 349 for (cp = cnp->cn_nameptr; *cp != '\0' && *cp != '/'; cp++) 350 cnp->cn_hash += (unsigned char)*cp; 351 cnp->cn_namelen = cp - cnp->cn_nameptr; 352 if (cnp->cn_namelen > NAME_MAX) { 353 error = ENAMETOOLONG; 354 goto bad; 355 } 356 #ifdef NAMEI_DIAGNOSTIC 357 { char c = *cp; 358 *cp = '\0'; 359 printf("{%s}: ", cnp->cn_nameptr); 360 *cp = c; } 361 #endif 362 ndp->ni_pathlen -= cnp->cn_namelen; 363 ndp->ni_next = cp; 364 /* 365 * If this component is followed by a slash, then move the pointer to 366 * the next component forward, and remember that this component must be 367 * a directory. 368 */ 369 if (*cp == '/') { 370 do { 371 cp++; 372 } while (*cp == '/'); 373 slashes = cp - ndp->ni_next; 374 ndp->ni_pathlen -= slashes; 375 ndp->ni_next = cp; 376 cnp->cn_flags |= REQUIREDIR; 377 } else { 378 slashes = 0; 379 cnp->cn_flags &= ~REQUIREDIR; 380 } 381 /* 382 * We do special processing on the last component, whether or not it's 383 * a directory. Cache all intervening lookups, but not the final one. 384 */ 385 if (*cp == '\0') { 386 if (docache) 387 cnp->cn_flags |= MAKEENTRY; 388 else 389 cnp->cn_flags &= ~MAKEENTRY; 390 cnp->cn_flags |= ISLASTCN; 391 } else { 392 cnp->cn_flags |= MAKEENTRY; 393 cnp->cn_flags &= ~ISLASTCN; 394 } 395 if (cnp->cn_namelen == 2 && 396 cnp->cn_nameptr[1] == '.' && cnp->cn_nameptr[0] == '.') 397 cnp->cn_flags |= ISDOTDOT; 398 else 399 cnp->cn_flags &= ~ISDOTDOT; 400 401 /* 402 * Handle "..": two special cases. 403 * 1. If at root directory (e.g. after chroot) 404 * or at absolute root directory 405 * then ignore it so can't get out. 406 * 2. If this vnode is the root of a mounted 407 * filesystem, then replace it with the 408 * vnode which was mounted on so we take the 409 * .. in the other file system. 410 */ 411 if (cnp->cn_flags & ISDOTDOT) { 412 for (;;) { 413 if (dp == ndp->ni_rootdir || dp == rootvnode) { 414 ndp->ni_dvp = dp; 415 ndp->ni_vp = dp; 416 VREF(dp); 417 goto nextname; 418 } 419 if ((dp->v_flag & VROOT) == 0 || 420 (cnp->cn_flags & NOCROSSMOUNT)) 421 break; 422 tdp = dp; 423 dp = dp->v_mount->mnt_vnodecovered; 424 vput(tdp); 425 VREF(dp); 426 vn_lock(dp, LK_EXCLUSIVE | LK_RETRY); 427 } 428 } 429 430 /* 431 * We now have a segment name to search for, and a directory to search. 432 */ 433 unionlookup: 434 ndp->ni_dvp = dp; 435 ndp->ni_vp = NULL; 436 cnp->cn_flags &= ~PDIRUNLOCK; 437 if ((error = VOP_LOOKUP(dp, &ndp->ni_vp, cnp)) != 0) { 438 #ifdef DIAGNOSTIC 439 if (ndp->ni_vp != NULL) 440 panic("leaf should be empty"); 441 #endif 442 #ifdef NAMEI_DIAGNOSTIC 443 printf("not found\n"); 444 #endif 445 if ((error == ENOENT) && 446 (dp->v_flag & VROOT) && 447 (dp->v_mount->mnt_flag & MNT_UNION)) { 448 tdp = dp; 449 dp = dp->v_mount->mnt_vnodecovered; 450 if (cnp->cn_flags & PDIRUNLOCK) 451 vrele(tdp); 452 else 453 vput(tdp); 454 VREF(dp); 455 vn_lock(dp, LK_EXCLUSIVE | LK_RETRY); 456 goto unionlookup; 457 } 458 459 if (error != EJUSTRETURN) 460 goto bad; 461 /* 462 * If this was not the last component, or there were trailing 463 * slashes, then the name must exist. 464 */ 465 if (cnp->cn_flags & REQUIREDIR) { 466 error = ENOENT; 467 goto bad; 468 } 469 /* 470 * If creating and at end of pathname, then can consider 471 * allowing file to be created. 472 */ 473 if (rdonly) { 474 error = EROFS; 475 goto bad; 476 } 477 /* 478 * We return with ni_vp NULL to indicate that the entry 479 * doesn't currently exist, leaving a pointer to the 480 * (possibly locked) directory inode in ndp->ni_dvp. 481 */ 482 if (cnp->cn_flags & SAVESTART) { 483 ndp->ni_startdir = ndp->ni_dvp; 484 VREF(ndp->ni_startdir); 485 } 486 return (0); 487 } 488 #ifdef NAMEI_DIAGNOSTIC 489 printf("found\n"); 490 #endif 491 492 /* 493 * Take into account any additional components consumed by the 494 * underlying filesystem. This will include any trailing slashes after 495 * the last component consumed. 496 */ 497 if (cnp->cn_consume > 0) { 498 ndp->ni_pathlen -= cnp->cn_consume - slashes; 499 ndp->ni_next += cnp->cn_consume - slashes; 500 cnp->cn_consume = 0; 501 if (ndp->ni_next[0] == '\0') 502 cnp->cn_flags |= ISLASTCN; 503 } 504 505 dp = ndp->ni_vp; 506 /* 507 * Check to see if the vnode has been mounted on; 508 * if so find the root of the mounted file system. 509 */ 510 while (dp->v_type == VDIR && (mp = dp->v_mountedhere) && 511 (cnp->cn_flags & NOCROSSMOUNT) == 0) { 512 if (vfs_busy(mp, 0, 0)) 513 continue; 514 VOP_UNLOCK(dp, 0); 515 error = VFS_ROOT(mp, &tdp); 516 vfs_unbusy(mp); 517 if (error) { 518 dpunlocked = 1; 519 goto bad2; 520 } 521 vrele(dp); 522 ndp->ni_vp = dp = tdp; 523 } 524 525 /* 526 * Check for symbolic link. Back up over any slashes that we skipped, 527 * as we will need them again. 528 */ 529 if ((dp->v_type == VLNK) && (cnp->cn_flags & (FOLLOW|REQUIREDIR))) { 530 ndp->ni_pathlen += slashes; 531 ndp->ni_next -= slashes; 532 cnp->cn_flags |= ISSYMLINK; 533 return (0); 534 } 535 536 /* 537 * Check for directory, if the component was followed by a series of 538 * slashes. 539 */ 540 if ((dp->v_type != VDIR) && (cnp->cn_flags & REQUIREDIR)) { 541 error = ENOTDIR; 542 goto bad2; 543 } 544 545 nextname: 546 /* 547 * Not a symbolic link. If this was not the last component, then 548 * continue at the next component, else return. 549 */ 550 if (!(cnp->cn_flags & ISLASTCN)) { 551 cnp->cn_nameptr = ndp->ni_next; 552 vrele(ndp->ni_dvp); 553 goto dirloop; 554 } 555 556 terminal: 557 /* 558 * Disallow directory write attempts on read-only file systems. 559 */ 560 if (rdonly && 561 (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME)) { 562 /* 563 * Disallow directory write attempts on read-only 564 * file systems. 565 */ 566 error = EROFS; 567 goto bad2; 568 } 569 if (ndp->ni_dvp != NULL) { 570 if (cnp->cn_flags & SAVESTART) { 571 ndp->ni_startdir = ndp->ni_dvp; 572 VREF(ndp->ni_startdir); 573 } 574 if (!wantparent) 575 vrele(ndp->ni_dvp); 576 } 577 if ((cnp->cn_flags & LOCKLEAF) == 0) 578 VOP_UNLOCK(dp, 0); 579 return (0); 580 581 bad2: 582 if ((cnp->cn_flags & LOCKPARENT) && (cnp->cn_flags & ISLASTCN) && 583 ((cnp->cn_flags & PDIRUNLOCK) == 0)) 584 VOP_UNLOCK(ndp->ni_dvp, 0); 585 vrele(ndp->ni_dvp); 586 bad: 587 if (dpunlocked) 588 vrele(dp); 589 else 590 vput(dp); 591 ndp->ni_vp = NULL; 592 return (error); 593 } 594 595 /* 596 * Reacquire a path name component. 597 */ 598 int 599 relookup(dvp, vpp, cnp) 600 struct vnode *dvp, **vpp; 601 struct componentname *cnp; 602 { 603 struct vnode *dp = 0; /* the directory we are searching */ 604 int docache; /* == 0 do not cache last component */ 605 int wantparent; /* 1 => wantparent or lockparent flag */ 606 int rdonly; /* lookup read-only flag bit */ 607 int error = 0; 608 #ifdef NAMEI_DIAGNOSTIC 609 int newhash; /* DEBUG: check name hash */ 610 char *cp; /* DEBUG: check name ptr/len */ 611 #endif 612 613 /* 614 * Setup: break out flag bits into variables. 615 */ 616 wantparent = cnp->cn_flags & (LOCKPARENT|WANTPARENT); 617 docache = (cnp->cn_flags & NOCACHE) ^ NOCACHE; 618 if (cnp->cn_nameiop == DELETE || 619 (wantparent && cnp->cn_nameiop != CREATE)) 620 docache = 0; 621 rdonly = cnp->cn_flags & RDONLY; 622 cnp->cn_flags &= ~ISSYMLINK; 623 dp = dvp; 624 vn_lock(dp, LK_EXCLUSIVE | LK_RETRY); 625 626 /* dirloop: */ 627 /* 628 * Search a new directory. 629 * 630 * The cn_hash value is for use by vfs_cache. 631 * The last component of the filename is left accessible via 632 * cnp->cn_nameptr for callers that need the name. Callers needing 633 * the name set the SAVENAME flag. When done, they assume 634 * responsibility for freeing the pathname buffer. 635 */ 636 #ifdef NAMEI_DIAGNOSTIC 637 for (newhash = 0, cp = cnp->cn_nameptr; *cp != 0 && *cp != '/'; cp++) 638 newhash += (unsigned char)*cp; 639 if (newhash != cnp->cn_hash) 640 panic("relookup: bad hash"); 641 if (cnp->cn_namelen != cp - cnp->cn_nameptr) 642 panic ("relookup: bad len"); 643 if (*cp != 0) 644 panic("relookup: not last component"); 645 printf("{%s}: ", cnp->cn_nameptr); 646 #endif 647 648 /* 649 * Check for degenerate name (e.g. / or "") 650 * which is a way of talking about a directory, 651 * e.g. like "/." or ".". 652 */ 653 if (cnp->cn_nameptr[0] == '\0') 654 panic("relookup: null name"); 655 656 if (cnp->cn_flags & ISDOTDOT) 657 panic ("relookup: lookup on dot-dot"); 658 659 /* 660 * We now have a segment name to search for, and a directory to search. 661 */ 662 if ((error = VOP_LOOKUP(dp, vpp, cnp)) != 0) { 663 #ifdef DIAGNOSTIC 664 if (*vpp != NULL) 665 panic("leaf should be empty"); 666 #endif 667 if (error != EJUSTRETURN) 668 goto bad; 669 /* 670 * If creating and at end of pathname, then can consider 671 * allowing file to be created. 672 */ 673 if (rdonly) { 674 error = EROFS; 675 goto bad; 676 } 677 /* ASSERT(dvp == ndp->ni_startdir) */ 678 if (cnp->cn_flags & SAVESTART) 679 VREF(dvp); 680 /* 681 * We return with ni_vp NULL to indicate that the entry 682 * doesn't currently exist, leaving a pointer to the 683 * (possibly locked) directory inode in ndp->ni_dvp. 684 */ 685 return (0); 686 } 687 dp = *vpp; 688 689 #ifdef DIAGNOSTIC 690 /* 691 * Check for symbolic link 692 */ 693 if (dp->v_type == VLNK && (cnp->cn_flags & FOLLOW)) 694 panic ("relookup: symlink found.\n"); 695 #endif 696 697 /* 698 * Check for read-only file systems. 699 */ 700 if (rdonly && 701 (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME)) { 702 error = EROFS; 703 goto bad2; 704 } 705 /* ASSERT(dvp == ndp->ni_startdir) */ 706 if (cnp->cn_flags & SAVESTART) 707 VREF(dvp); 708 if (!wantparent) 709 vrele(dvp); 710 if ((cnp->cn_flags & LOCKLEAF) == 0) 711 VOP_UNLOCK(dp, 0); 712 return (0); 713 714 bad2: 715 if ((cnp->cn_flags & LOCKPARENT) && (cnp->cn_flags & ISLASTCN)) 716 VOP_UNLOCK(dvp, 0); 717 vrele(dvp); 718 bad: 719 vput(dp); 720 *vpp = NULL; 721 return (error); 722 } 723
Indexes created Sat Sep 20 22:09:52 GMT 2025