1 /* $NetBSD: vfs_lookup.c,v 1.32 1999/08/03 18:17:24 wrstuden 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 /* 62 * Convert a pathname into a pointer to a locked inode. 63 * 64 * The FOLLOW flag is set when symbolic links are to be followed 65 * when they occur at the end of the name translation process. 66 * Symbolic links are always followed for all other pathname 67 * components other than the last. 68 * 69 * The segflg defines whether the name is to be copied from user 70 * space or kernel space. 71 * 72 * Overall outline of namei: 73 * 74 * copy in name 75 * get starting directory 76 * while (!done && !error) { 77 * call lookup to search path. 78 * if symbolic link, massage name in buffer and continue 79 * } 80 */ 81 int 82 namei(ndp) 83 register struct nameidata *ndp; 84 { 85 struct cwdinfo *cwdi; /* pointer to cwd state */ 86 register char *cp; /* pointer into pathname argument */ 87 register struct vnode *dp; /* the directory we are searching */ 88 struct iovec aiov; /* uio for reading symbolic links */ 89 struct uio auio; 90 int error, linklen; 91 struct componentname *cnp = &ndp->ni_cnd; 92 93 ndp->ni_cnd.cn_cred = ndp->ni_cnd.cn_proc->p_ucred; 94 #ifdef DIAGNOSTIC 95 if (!cnp->cn_cred || !cnp->cn_proc) 96 panic ("namei: bad cred/proc"); 97 if (cnp->cn_nameiop & (~OPMASK)) 98 panic ("namei: nameiop contaminated with flags"); 99 if (cnp->cn_flags & OPMASK) 100 panic ("namei: flags contaminated with nameiops"); 101 #endif 102 cwdi = cnp->cn_proc->p_cwdi; 103 104 /* 105 * Get a buffer for the name to be translated, and copy the 106 * name into the buffer. 107 */ 108 if ((cnp->cn_flags & HASBUF) == 0) 109 MALLOC(cnp->cn_pnbuf, caddr_t, MAXPATHLEN, M_NAMEI, M_WAITOK); 110 if (ndp->ni_segflg == UIO_SYSSPACE) 111 error = copystr(ndp->ni_dirp, cnp->cn_pnbuf, 112 MAXPATHLEN, &ndp->ni_pathlen); 113 else 114 error = copyinstr(ndp->ni_dirp, cnp->cn_pnbuf, 115 MAXPATHLEN, &ndp->ni_pathlen); 116 117 /* 118 * POSIX.1 requirement: "" is not a valid file name. 119 */ 120 if (!error && ndp->ni_pathlen == 1) 121 error = ENOENT; 122 123 if (error) { 124 free(cnp->cn_pnbuf, M_NAMEI); 125 ndp->ni_vp = NULL; 126 return (error); 127 } 128 ndp->ni_loopcnt = 0; 129 130 #ifdef KTRACE 131 if (KTRPOINT(cnp->cn_proc, KTR_NAMEI)) 132 ktrnamei(cnp->cn_proc->p_tracep, cnp->cn_pnbuf); 133 #endif 134 135 /* 136 * Get starting point for the translation. 137 */ 138 if ((ndp->ni_rootdir = cwdi->cwdi_rdir) == NULL) 139 ndp->ni_rootdir = rootvnode; 140 /* 141 * Check if starting from root directory or current directory. 142 */ 143 if (cnp->cn_pnbuf[0] == '/') { 144 dp = ndp->ni_rootdir; 145 VREF(dp); 146 } else { 147 dp = cwdi->cwdi_cdir; 148 VREF(dp); 149 } 150 for (;;) { 151 cnp->cn_nameptr = cnp->cn_pnbuf; 152 ndp->ni_startdir = dp; 153 if ((error = lookup(ndp)) != 0) { 154 FREE(cnp->cn_pnbuf, M_NAMEI); 155 return (error); 156 } 157 /* 158 * Check for symbolic link 159 */ 160 if ((cnp->cn_flags & ISSYMLINK) == 0) { 161 if ((cnp->cn_flags & (SAVENAME | SAVESTART)) == 0) 162 FREE(cnp->cn_pnbuf, M_NAMEI); 163 else 164 cnp->cn_flags |= HASBUF; 165 return (0); 166 } 167 if ((cnp->cn_flags & LOCKPARENT) && (cnp->cn_flags & ISLASTCN)) 168 VOP_UNLOCK(ndp->ni_dvp, 0); 169 if (ndp->ni_loopcnt++ >= MAXSYMLINKS) { 170 error = ELOOP; 171 break; 172 } 173 if (ndp->ni_vp->v_mount->mnt_flag & MNT_SYMPERM) { 174 error = VOP_ACCESS(ndp->ni_vp, VEXEC, cnp->cn_cred, 175 cnp->cn_proc); 176 if (error != 0) 177 break; 178 } 179 if (ndp->ni_pathlen > 1) 180 MALLOC(cp, char *, MAXPATHLEN, M_NAMEI, M_WAITOK); 181 else 182 cp = cnp->cn_pnbuf; 183 aiov.iov_base = cp; 184 aiov.iov_len = MAXPATHLEN; 185 auio.uio_iov = &aiov; 186 auio.uio_iovcnt = 1; 187 auio.uio_offset = 0; 188 auio.uio_rw = UIO_READ; 189 auio.uio_segflg = UIO_SYSSPACE; 190 auio.uio_procp = (struct proc *)0; 191 auio.uio_resid = MAXPATHLEN; 192 error = VOP_READLINK(ndp->ni_vp, &auio, cnp->cn_cred); 193 if (error) { 194 badlink: 195 if (ndp->ni_pathlen > 1) 196 FREE(cp, M_NAMEI); 197 break; 198 } 199 linklen = MAXPATHLEN - auio.uio_resid; 200 if (linklen == 0) { 201 error = ENOENT; 202 goto badlink; 203 } 204 if (linklen + ndp->ni_pathlen >= MAXPATHLEN) { 205 error = ENAMETOOLONG; 206 goto badlink; 207 } 208 if (ndp->ni_pathlen > 1) { 209 memcpy(cp + linklen, ndp->ni_next, ndp->ni_pathlen); 210 FREE(cnp->cn_pnbuf, M_NAMEI); 211 cnp->cn_pnbuf = cp; 212 } else 213 cnp->cn_pnbuf[linklen] = '\0'; 214 ndp->ni_pathlen += linklen; 215 vput(ndp->ni_vp); 216 dp = ndp->ni_dvp; 217 /* 218 * Check if root directory should replace current directory. 219 */ 220 if (cnp->cn_pnbuf[0] == '/') { 221 vrele(dp); 222 dp = ndp->ni_rootdir; 223 VREF(dp); 224 } 225 } 226 FREE(cnp->cn_pnbuf, M_NAMEI); 227 vrele(ndp->ni_dvp); 228 vput(ndp->ni_vp); 229 ndp->ni_vp = NULL; 230 return (error); 231 } 232 233 /* 234 * Search a pathname. 235 * This is a very central and rather complicated routine. 236 * 237 * The pathname is pointed to by ni_ptr and is of length ni_pathlen. 238 * The starting directory is taken from ni_startdir. The pathname is 239 * descended until done, or a symbolic link is encountered. The variable 240 * ni_more is clear if the path is completed; it is set to one if a 241 * symbolic link needing interpretation is encountered. 242 * 243 * The flag argument is LOOKUP, CREATE, RENAME, or DELETE depending on 244 * whether the name is to be looked up, created, renamed, or deleted. 245 * When CREATE, RENAME, or DELETE is specified, information usable in 246 * creating, renaming, or deleting a directory entry may be calculated. 247 * If flag has LOCKPARENT or'ed into it, the parent directory is returned 248 * locked. If flag has WANTPARENT or'ed into it, the parent directory is 249 * returned unlocked. Otherwise the parent directory is not returned. If 250 * the target of the pathname exists and LOCKLEAF is or'ed into the flag 251 * the target is returned locked, otherwise it is returned unlocked. 252 * When creating or renaming and LOCKPARENT is specified, the target may not 253 * be ".". When deleting and LOCKPARENT is specified, the target may be ".". 254 * 255 * Overall outline of lookup: 256 * 257 * dirloop: 258 * identify next component of name at ndp->ni_ptr 259 * handle degenerate case where name is null string 260 * if .. and crossing mount points and on mounted filesys, find parent 261 * call VOP_LOOKUP routine for next component name 262 * directory vnode returned in ni_dvp, unlocked unless LOCKPARENT set 263 * component vnode returned in ni_vp (if it exists), locked. 264 * if result vnode is mounted on and crossing mount points, 265 * find mounted on vnode 266 * if more components of name, do next level at dirloop 267 * return the answer in ni_vp, locked if LOCKLEAF set 268 * if LOCKPARENT set, return locked parent in ni_dvp 269 * if WANTPARENT set, return unlocked parent in ni_dvp 270 */ 271 int 272 lookup(ndp) 273 register struct nameidata *ndp; 274 { 275 register const char *cp; /* pointer into pathname argument */ 276 register struct vnode *dp = 0; /* the directory we are searching */ 277 struct vnode *tdp; /* saved dp */ 278 struct mount *mp; /* mount table entry */ 279 int docache; /* == 0 do not cache last component */ 280 int wantparent; /* 1 => wantparent or lockparent flag */ 281 int rdonly; /* lookup read-only flag bit */ 282 int error = 0; 283 int slashes; 284 int dpunlocked = 0; /* dp has already been unlocked */ 285 struct componentname *cnp = &ndp->ni_cnd; 286 287 /* 288 * Setup: break out flag bits into variables. 289 */ 290 wantparent = cnp->cn_flags & (LOCKPARENT | WANTPARENT); 291 docache = (cnp->cn_flags & NOCACHE) ^ NOCACHE; 292 if (cnp->cn_nameiop == DELETE || 293 (wantparent && cnp->cn_nameiop != CREATE)) 294 docache = 0; 295 rdonly = cnp->cn_flags & RDONLY; 296 ndp->ni_dvp = NULL; 297 cnp->cn_flags &= ~ISSYMLINK; 298 dp = ndp->ni_startdir; 299 ndp->ni_startdir = NULLVP; 300 vn_lock(dp, LK_EXCLUSIVE | LK_RETRY); 301 302 /* 303 * If we have a leading string of slashes, remove them, and just make 304 * sure the current node is a directory. 305 */ 306 cp = cnp->cn_nameptr; 307 if (*cp == '/') { 308 do { 309 cp++; 310 } while (*cp == '/'); 311 ndp->ni_pathlen -= cp - cnp->cn_nameptr; 312 cnp->cn_nameptr = cp; 313 314 if (dp->v_type != VDIR) { 315 error = ENOTDIR; 316 goto bad; 317 } 318 319 /* 320 * If we've exhausted the path name, then just return the 321 * current node. If the caller requested the parent node (i.e. 322 * it's a CREATE, DELETE, or RENAME), and we don't have one 323 * (because this is the root directory), then we must fail. 324 */ 325 if (cnp->cn_nameptr[0] == '\0') { 326 if (ndp->ni_dvp == NULL && wantparent) { 327 error = EISDIR; 328 goto bad; 329 } 330 ndp->ni_vp = dp; 331 cnp->cn_flags |= ISLASTCN; 332 goto terminal; 333 } 334 } 335 336 dirloop: 337 /* 338 * Search a new directory. 339 * 340 * The cn_hash value is for use by vfs_cache. 341 * The last component of the filename is left accessible via 342 * cnp->cn_nameptr for callers that need the name. Callers needing 343 * the name set the SAVENAME flag. When done, they assume 344 * responsibility for freeing the pathname buffer. 345 */ 346 cnp->cn_consume = 0; 347 cnp->cn_hash = 0; 348 for (cp = cnp->cn_nameptr; *cp != '\0' && *cp != '/'; cp++) 349 cnp->cn_hash += (unsigned char)*cp; 350 cnp->cn_namelen = cp - cnp->cn_nameptr; 351 if (cnp->cn_namelen > NAME_MAX) { 352 error = ENAMETOOLONG; 353 goto bad; 354 } 355 #ifdef NAMEI_DIAGNOSTIC 356 { char c = *cp; 357 *cp = '\0'; 358 printf("{%s}: ", cnp->cn_nameptr); 359 *cp = c; } 360 #endif 361 ndp->ni_pathlen -= cnp->cn_namelen; 362 ndp->ni_next = cp; 363 /* 364 * If this component is followed by a slash, then move the pointer to 365 * the next component forward, and remember that this component must be 366 * a directory. 367 */ 368 if (*cp == '/') { 369 do { 370 cp++; 371 } while (*cp == '/'); 372 slashes = cp - ndp->ni_next; 373 ndp->ni_pathlen -= slashes; 374 ndp->ni_next = cp; 375 cnp->cn_flags |= REQUIREDIR; 376 } else { 377 slashes = 0; 378 cnp->cn_flags &= ~REQUIREDIR; 379 } 380 /* 381 * We do special processing on the last component, whether or not it's 382 * a directory. Cache all intervening lookups, but not the final one. 383 */ 384 if (*cp == '\0') { 385 if (docache) 386 cnp->cn_flags |= MAKEENTRY; 387 else 388 cnp->cn_flags &= ~MAKEENTRY; 389 cnp->cn_flags |= ISLASTCN; 390 } else { 391 cnp->cn_flags |= MAKEENTRY; 392 cnp->cn_flags &= ~ISLASTCN; 393 } 394 if (cnp->cn_namelen == 2 && 395 cnp->cn_nameptr[1] == '.' && cnp->cn_nameptr[0] == '.') 396 cnp->cn_flags |= ISDOTDOT; 397 else 398 cnp->cn_flags &= ~ISDOTDOT; 399 400 /* 401 * Handle "..": two special cases. 402 * 1. If at root directory (e.g. after chroot) 403 * or at absolute root directory 404 * then ignore it so can't get out. 405 * 2. If this vnode is the root of a mounted 406 * filesystem, then replace it with the 407 * vnode which was mounted on so we take the 408 * .. in the other file system. 409 */ 410 if (cnp->cn_flags & ISDOTDOT) { 411 for (;;) { 412 if (dp == ndp->ni_rootdir || dp == rootvnode) { 413 ndp->ni_dvp = dp; 414 ndp->ni_vp = dp; 415 VREF(dp); 416 goto nextname; 417 } 418 if ((dp->v_flag & VROOT) == 0 || 419 (cnp->cn_flags & NOCROSSMOUNT)) 420 break; 421 tdp = dp; 422 dp = dp->v_mount->mnt_vnodecovered; 423 vput(tdp); 424 VREF(dp); 425 vn_lock(dp, LK_EXCLUSIVE | LK_RETRY); 426 } 427 } 428 429 /* 430 * We now have a segment name to search for, and a directory to search. 431 */ 432 unionlookup: 433 ndp->ni_dvp = dp; 434 ndp->ni_vp = NULL; 435 cnp->cn_flags &= ~PDIRUNLOCK; 436 if ((error = VOP_LOOKUP(dp, &ndp->ni_vp, cnp)) != 0) { 437 #ifdef DIAGNOSTIC 438 if (ndp->ni_vp != NULL) 439 panic("leaf should be empty"); 440 #endif 441 #ifdef NAMEI_DIAGNOSTIC 442 printf("not found\n"); 443 #endif 444 if ((error == ENOENT) && 445 (dp->v_flag & VROOT) && 446 (dp->v_mount->mnt_flag & MNT_UNION)) { 447 tdp = dp; 448 dp = dp->v_mount->mnt_vnodecovered; 449 if (cnp->cn_flags & PDIRUNLOCK) 450 vrele(tdp); 451 else 452 vput(tdp); 453 VREF(dp); 454 vn_lock(dp, LK_EXCLUSIVE | LK_RETRY); 455 goto unionlookup; 456 } 457 458 if (error != EJUSTRETURN) 459 goto bad; 460 /* 461 * If this was not the last component, or there were trailing 462 * slashes, then the name must exist. 463 */ 464 if (cnp->cn_flags & REQUIREDIR) { 465 error = ENOENT; 466 goto bad; 467 } 468 /* 469 * If creating and at end of pathname, then can consider 470 * allowing file to be created. 471 */ 472 if (rdonly) { 473 error = EROFS; 474 goto bad; 475 } 476 /* 477 * We return with ni_vp NULL to indicate that the entry 478 * doesn't currently exist, leaving a pointer to the 479 * (possibly locked) directory inode in ndp->ni_dvp. 480 */ 481 if (cnp->cn_flags & SAVESTART) { 482 ndp->ni_startdir = ndp->ni_dvp; 483 VREF(ndp->ni_startdir); 484 } 485 return (0); 486 } 487 #ifdef NAMEI_DIAGNOSTIC 488 printf("found\n"); 489 #endif 490 491 /* 492 * Take into account any additional components consumed by the 493 * underlying filesystem. This will include any trailing slashes after 494 * the last component consumed. 495 */ 496 if (cnp->cn_consume > 0) { 497 ndp->ni_pathlen -= cnp->cn_consume - slashes; 498 ndp->ni_next += cnp->cn_consume - slashes; 499 cnp->cn_consume = 0; 500 if (ndp->ni_next[0] == '\0') 501 cnp->cn_flags |= ISLASTCN; 502 } 503 504 dp = ndp->ni_vp; 505 /* 506 * Check to see if the vnode has been mounted on; 507 * if so find the root of the mounted file system. 508 */ 509 while (dp->v_type == VDIR && (mp = dp->v_mountedhere) && 510 (cnp->cn_flags & NOCROSSMOUNT) == 0) { 511 if (vfs_busy(mp, 0, 0)) 512 continue; 513 VOP_UNLOCK(dp, 0); 514 error = VFS_ROOT(mp, &tdp); 515 vfs_unbusy(mp); 516 if (error) { 517 dpunlocked = 1; 518 goto bad2; 519 } 520 vrele(dp); 521 ndp->ni_vp = dp = tdp; 522 } 523 524 /* 525 * Check for symbolic link. Back up over any slashes that we skipped, 526 * as we will need them again. 527 */ 528 if ((dp->v_type == VLNK) && (cnp->cn_flags & (FOLLOW|REQUIREDIR))) { 529 ndp->ni_pathlen += slashes; 530 ndp->ni_next -= slashes; 531 cnp->cn_flags |= ISSYMLINK; 532 return (0); 533 } 534 535 /* 536 * Check for directory, if the component was followed by a series of 537 * slashes. 538 */ 539 if ((dp->v_type != VDIR) && (cnp->cn_flags & REQUIREDIR)) { 540 error = ENOTDIR; 541 goto bad2; 542 } 543 544 nextname: 545 /* 546 * Not a symbolic link. If this was not the last component, then 547 * continue at the next component, else return. 548 */ 549 if (!(cnp->cn_flags & ISLASTCN)) { 550 cnp->cn_nameptr = ndp->ni_next; 551 vrele(ndp->ni_dvp); 552 goto dirloop; 553 } 554 555 terminal: 556 /* 557 * Disallow directory write attempts on read-only file systems. 558 */ 559 if (rdonly && 560 (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME)) { 561 /* 562 * Disallow directory write attempts on read-only 563 * file systems. 564 */ 565 error = EROFS; 566 goto bad2; 567 } 568 if (ndp->ni_dvp != NULL) { 569 if (cnp->cn_flags & SAVESTART) { 570 ndp->ni_startdir = ndp->ni_dvp; 571 VREF(ndp->ni_startdir); 572 } 573 if (!wantparent) 574 vrele(ndp->ni_dvp); 575 } 576 if ((cnp->cn_flags & LOCKLEAF) == 0) 577 VOP_UNLOCK(dp, 0); 578 return (0); 579 580 bad2: 581 if ((cnp->cn_flags & LOCKPARENT) && (cnp->cn_flags & ISLASTCN) && 582 ((cnp->cn_flags & PDIRUNLOCK) == 0)) 583 VOP_UNLOCK(ndp->ni_dvp, 0); 584 vrele(ndp->ni_dvp); 585 bad: 586 if (dpunlocked) 587 vrele(dp); 588 else 589 vput(dp); 590 ndp->ni_vp = NULL; 591 return (error); 592 } 593 594 /* 595 * Reacquire a path name component. 596 */ 597 int 598 relookup(dvp, vpp, cnp) 599 struct vnode *dvp, **vpp; 600 struct componentname *cnp; 601 { 602 struct vnode *dp = 0; /* the directory we are searching */ 603 int docache; /* == 0 do not cache last component */ 604 int wantparent; /* 1 => wantparent or lockparent flag */ 605 int rdonly; /* lookup read-only flag bit */ 606 int error = 0; 607 #ifdef NAMEI_DIAGNOSTIC 608 int newhash; /* DEBUG: check name hash */ 609 char *cp; /* DEBUG: check name ptr/len */ 610 #endif 611 612 /* 613 * Setup: break out flag bits into variables. 614 */ 615 wantparent = cnp->cn_flags & (LOCKPARENT|WANTPARENT); 616 docache = (cnp->cn_flags & NOCACHE) ^ NOCACHE; 617 if (cnp->cn_nameiop == DELETE || 618 (wantparent && cnp->cn_nameiop != CREATE)) 619 docache = 0; 620 rdonly = cnp->cn_flags & RDONLY; 621 cnp->cn_flags &= ~ISSYMLINK; 622 dp = dvp; 623 vn_lock(dp, LK_EXCLUSIVE | LK_RETRY); 624 625 /* dirloop: */ 626 /* 627 * Search a new directory. 628 * 629 * The cn_hash value is for use by vfs_cache. 630 * The last component of the filename is left accessible via 631 * cnp->cn_nameptr for callers that need the name. Callers needing 632 * the name set the SAVENAME flag. When done, they assume 633 * responsibility for freeing the pathname buffer. 634 */ 635 #ifdef NAMEI_DIAGNOSTIC 636 for (newhash = 0, cp = cnp->cn_nameptr; *cp != 0 && *cp != '/'; cp++) 637 newhash += (unsigned char)*cp; 638 if (newhash != cnp->cn_hash) 639 panic("relookup: bad hash"); 640 if (cnp->cn_namelen != cp - cnp->cn_nameptr) 641 panic ("relookup: bad len"); 642 if (*cp != 0) 643 panic("relookup: not last component"); 644 printf("{%s}: ", cnp->cn_nameptr); 645 #endif 646 647 /* 648 * Check for degenerate name (e.g. / or "") 649 * which is a way of talking about a directory, 650 * e.g. like "/." or ".". 651 */ 652 if (cnp->cn_nameptr[0] == '\0') 653 panic("relookup: null name"); 654 655 if (cnp->cn_flags & ISDOTDOT) 656 panic ("relookup: lookup on dot-dot"); 657 658 /* 659 * We now have a segment name to search for, and a directory to search. 660 */ 661 if ((error = VOP_LOOKUP(dp, vpp, cnp)) != 0) { 662 #ifdef DIAGNOSTIC 663 if (*vpp != NULL) 664 panic("leaf should be empty"); 665 #endif 666 if (error != EJUSTRETURN) 667 goto bad; 668 /* 669 * If creating and at end of pathname, then can consider 670 * allowing file to be created. 671 */ 672 if (rdonly) { 673 error = EROFS; 674 goto bad; 675 } 676 /* ASSERT(dvp == ndp->ni_startdir) */ 677 if (cnp->cn_flags & SAVESTART) 678 VREF(dvp); 679 /* 680 * We return with ni_vp NULL to indicate that the entry 681 * doesn't currently exist, leaving a pointer to the 682 * (possibly locked) directory inode in ndp->ni_dvp. 683 */ 684 return (0); 685 } 686 dp = *vpp; 687 688 #ifdef DIAGNOSTIC 689 /* 690 * Check for symbolic link 691 */ 692 if (dp->v_type == VLNK && (cnp->cn_flags & FOLLOW)) 693 panic ("relookup: symlink found.\n"); 694 #endif 695 696 /* 697 * Check for read-only file systems. 698 */ 699 if (rdonly && 700 (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME)) { 701 error = EROFS; 702 goto bad2; 703 } 704 /* ASSERT(dvp == ndp->ni_startdir) */ 705 if (cnp->cn_flags & SAVESTART) 706 VREF(dvp); 707 if (!wantparent) 708 vrele(dvp); 709 if ((cnp->cn_flags & LOCKLEAF) == 0) 710 VOP_UNLOCK(dp, 0); 711 return (0); 712 713 bad2: 714 if ((cnp->cn_flags & LOCKPARENT) && (cnp->cn_flags & ISLASTCN)) 715 VOP_UNLOCK(dvp, 0); 716 vrele(dvp); 717 bad: 718 vput(dp); 719 *vpp = NULL; 720 return (error); 721 } 722