1 /* 2 * Copyright (c) 2004 The DragonFly Project. All rights reserved. 3 * 4 * This code is derived from software contributed to The DragonFly Project 5 * by Matthew Dillon <dillon@backplane.com> 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in 15 * the documentation and/or other materials provided with the 16 * distribution. 17 * 3. Neither the name of The DragonFly Project nor the names of its 18 * contributors may be used to endorse or promote products derived 19 * from this software without specific, prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 22 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 23 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 24 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 25 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 26 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING, 27 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 28 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 29 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 30 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 31 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 */ 34 /* 35 * nlookup() is the 'new' namei interface. Rather then return directory and 36 * leaf vnodes (in various lock states) the new interface instead deals in 37 * namecache records. Namecache records may represent both a positive or 38 * a negative hit. The namespace is locked via the namecache record instead 39 * of via the vnode, and only the leaf namecache record (representing the 40 * filename) needs to be locked. 41 * 42 * This greatly improves filesystem parallelism and is a huge simplification 43 * of the API verses the old vnode locking / namei scheme. 44 * 45 * Filesystems must actively control the caching aspects of the namecache, 46 * and since namecache pointers are used as handles they are non-optional 47 * even for filesystems which do not generally wish to cache things. It is 48 * intended that a separate cache coherency API will be constructed to handle 49 * these issues. 50 */ 51 52 #include "opt_ktrace.h" 53 54 #include <sys/param.h> 55 #include <sys/systm.h> 56 #include <sys/kernel.h> 57 #include <sys/vnode.h> 58 #include <sys/mount.h> 59 #include <sys/filedesc.h> 60 #include <sys/proc.h> 61 #include <sys/namei.h> 62 #include <sys/nlookup.h> 63 #include <sys/malloc.h> 64 #include <sys/stat.h> 65 #include <sys/objcache.h> 66 #include <sys/file.h> 67 #include <sys/kcollect.h> 68 69 #ifdef KTRACE 70 #include <sys/ktrace.h> 71 #endif 72 73 static int naccess(struct nchandle *nch, int vmode, struct ucred *cred, 74 int *stickyp); 75 76 /* 77 * Initialize a nlookup() structure, early error return for copyin faults 78 * or a degenerate empty string (which is not allowed). 79 * 80 * The first process proc0's credentials are used if the calling thread 81 * is not associated with a process context. 82 * 83 * MPSAFE 84 */ 85 int 86 nlookup_init(struct nlookupdata *nd, 87 const char *path, enum uio_seg seg, int flags) 88 { 89 size_t pathlen; 90 struct proc *p; 91 thread_t td; 92 int error; 93 94 td = curthread; 95 p = td->td_proc; 96 97 /* 98 * note: the pathlen set by copy*str() includes the terminating \0. 99 */ 100 bzero(nd, sizeof(struct nlookupdata)); 101 nd->nl_path = objcache_get(namei_oc, M_WAITOK); 102 nd->nl_flags |= NLC_HASBUF; 103 if (seg == UIO_SYSSPACE) 104 error = copystr(path, nd->nl_path, MAXPATHLEN, &pathlen); 105 else 106 error = copyinstr(path, nd->nl_path, MAXPATHLEN, &pathlen); 107 108 /* 109 * Don't allow empty pathnames. 110 * POSIX.1 requirement: "" is not a vaild file name. 111 */ 112 if (error == 0 && pathlen <= 1) 113 error = ENOENT; 114 115 if (error == 0) { 116 if (p && p->p_fd) { 117 cache_copy_ncdir(p, &nd->nl_nch); 118 cache_copy(&p->p_fd->fd_nrdir, &nd->nl_rootnch); 119 if (p->p_fd->fd_njdir.ncp) 120 cache_copy(&p->p_fd->fd_njdir, &nd->nl_jailnch); 121 nd->nl_cred = td->td_ucred; 122 nd->nl_flags |= NLC_BORROWCRED | NLC_NCDIR; 123 } else { 124 cache_copy(&rootnch, &nd->nl_nch); 125 cache_copy(&nd->nl_nch, &nd->nl_rootnch); 126 cache_copy(&nd->nl_nch, &nd->nl_jailnch); 127 nd->nl_cred = proc0.p_ucred; 128 nd->nl_flags |= NLC_BORROWCRED; 129 } 130 nd->nl_td = td; 131 nd->nl_flags |= flags; 132 } else { 133 nlookup_done(nd); 134 } 135 return(error); 136 } 137 138 139 /* 140 * nlookup_init() for "at" family of syscalls. 141 * 142 * Works similarly to nlookup_init() but if path is relative and fd is not 143 * AT_FDCWD, path is interpreted relative to the directory pointed to by fd. 144 * In this case, the file entry pointed to by fd is ref'ed and returned in 145 * *fpp. 146 * 147 * If the call succeeds, nlookup_done_at() must be called to clean-up the nd 148 * and release the ref to the file entry. 149 */ 150 int 151 nlookup_init_at(struct nlookupdata *nd, struct file **fpp, int fd, 152 const char *path, enum uio_seg seg, int flags) 153 { 154 struct thread *td = curthread; 155 struct file* fp; 156 struct vnode *vp; 157 int error; 158 159 *fpp = NULL; 160 161 if ((error = nlookup_init(nd, path, seg, flags)) != 0) { 162 return (error); 163 } 164 165 if (nd->nl_path[0] != '/' && fd != AT_FDCWD) { 166 if ((error = holdvnode(td, fd, &fp)) != 0) 167 goto done; 168 vp = (struct vnode*)fp->f_data; 169 if (vp->v_type != VDIR || fp->f_nchandle.ncp == NULL) { 170 fdrop(fp); 171 fp = NULL; 172 error = ENOTDIR; 173 goto done; 174 } 175 if (nd->nl_flags & NLC_NCDIR) { 176 cache_drop_ncdir(&nd->nl_nch); 177 nd->nl_flags &= ~NLC_NCDIR; 178 } else { 179 cache_drop(&nd->nl_nch); 180 } 181 cache_copy(&fp->f_nchandle, &nd->nl_nch); 182 *fpp = fp; 183 } 184 185 186 done: 187 if (error) 188 nlookup_done(nd); 189 return (error); 190 191 } 192 193 /* 194 * This works similarly to nlookup_init() but does not assume a process 195 * context. rootnch is always chosen for the root directory and the cred 196 * and starting directory are supplied in arguments. 197 */ 198 int 199 nlookup_init_raw(struct nlookupdata *nd, 200 const char *path, enum uio_seg seg, int flags, 201 struct ucred *cred, struct nchandle *ncstart) 202 { 203 size_t pathlen; 204 thread_t td; 205 int error; 206 207 td = curthread; 208 209 bzero(nd, sizeof(struct nlookupdata)); 210 nd->nl_path = objcache_get(namei_oc, M_WAITOK); 211 nd->nl_flags |= NLC_HASBUF; 212 if (seg == UIO_SYSSPACE) 213 error = copystr(path, nd->nl_path, MAXPATHLEN, &pathlen); 214 else 215 error = copyinstr(path, nd->nl_path, MAXPATHLEN, &pathlen); 216 217 /* 218 * Don't allow empty pathnames. 219 * POSIX.1 requirement: "" is not a vaild file name. 220 */ 221 if (error == 0 && pathlen <= 1) 222 error = ENOENT; 223 224 if (error == 0) { 225 cache_copy(ncstart, &nd->nl_nch); 226 cache_copy(&rootnch, &nd->nl_rootnch); 227 cache_copy(&rootnch, &nd->nl_jailnch); 228 nd->nl_cred = crhold(cred); 229 nd->nl_td = td; 230 nd->nl_flags |= flags; 231 } else { 232 nlookup_done(nd); 233 } 234 return(error); 235 } 236 237 /* 238 * This works similarly to nlookup_init_raw() but does not rely 239 * on rootnch being initialized yet. 240 */ 241 int 242 nlookup_init_root(struct nlookupdata *nd, 243 const char *path, enum uio_seg seg, int flags, 244 struct ucred *cred, struct nchandle *ncstart, 245 struct nchandle *ncroot) 246 { 247 size_t pathlen; 248 thread_t td; 249 int error; 250 251 td = curthread; 252 253 bzero(nd, sizeof(struct nlookupdata)); 254 nd->nl_path = objcache_get(namei_oc, M_WAITOK); 255 nd->nl_flags |= NLC_HASBUF; 256 if (seg == UIO_SYSSPACE) 257 error = copystr(path, nd->nl_path, MAXPATHLEN, &pathlen); 258 else 259 error = copyinstr(path, nd->nl_path, MAXPATHLEN, &pathlen); 260 261 /* 262 * Don't allow empty pathnames. 263 * POSIX.1 requirement: "" is not a vaild file name. 264 */ 265 if (error == 0 && pathlen <= 1) 266 error = ENOENT; 267 268 if (error == 0) { 269 cache_copy(ncstart, &nd->nl_nch); 270 cache_copy(ncroot, &nd->nl_rootnch); 271 cache_copy(ncroot, &nd->nl_jailnch); 272 nd->nl_cred = crhold(cred); 273 nd->nl_td = td; 274 nd->nl_flags |= flags; 275 } else { 276 nlookup_done(nd); 277 } 278 return(error); 279 } 280 281 #if 0 282 /* 283 * Set a different credential; this credential will be used by future 284 * operations performed on nd.nl_open_vp and nlookupdata structure. 285 */ 286 void 287 nlookup_set_cred(struct nlookupdata *nd, struct ucred *cred) 288 { 289 KKASSERT(nd->nl_cred != NULL); 290 291 if (nd->nl_cred != cred) { 292 cred = crhold(cred); 293 if ((nd->nl_flags & NLC_BORROWCRED) == 0) 294 crfree(nd->nl_cred); 295 nd->nl_flags &= ~NLC_BORROWCRED; 296 nd->nl_cred = cred; 297 } 298 } 299 #endif 300 301 /* 302 * Cleanup a nlookupdata structure after we are through with it. This may 303 * be called on any nlookupdata structure initialized with nlookup_init(). 304 * Calling nlookup_done() is mandatory in all cases except where nlookup_init() 305 * returns an error, even if as a consumer you believe you have taken all 306 * dynamic elements out of the nlookupdata structure. 307 */ 308 void 309 nlookup_done(struct nlookupdata *nd) 310 { 311 if (nd->nl_nch.ncp) { 312 if (nd->nl_flags & NLC_NCPISLOCKED) { 313 nd->nl_flags &= ~NLC_NCPISLOCKED; 314 cache_unlock(&nd->nl_nch); 315 } 316 if (nd->nl_flags & NLC_NCDIR) { 317 cache_drop_ncdir(&nd->nl_nch); 318 nd->nl_flags &= ~NLC_NCDIR; 319 } else { 320 cache_drop(&nd->nl_nch); /* NULL's out the nch */ 321 } 322 } 323 if (nd->nl_rootnch.ncp) 324 cache_drop_and_cache(&nd->nl_rootnch); 325 if (nd->nl_jailnch.ncp) 326 cache_drop_and_cache(&nd->nl_jailnch); 327 if ((nd->nl_flags & NLC_HASBUF) && nd->nl_path) { 328 objcache_put(namei_oc, nd->nl_path); 329 nd->nl_path = NULL; 330 } 331 if (nd->nl_cred) { 332 if ((nd->nl_flags & NLC_BORROWCRED) == 0) 333 crfree(nd->nl_cred); 334 nd->nl_cred = NULL; 335 nd->nl_flags &= ~NLC_BORROWCRED; 336 } 337 if (nd->nl_open_vp) { 338 if (nd->nl_flags & NLC_LOCKVP) { 339 vn_unlock(nd->nl_open_vp); 340 nd->nl_flags &= ~NLC_LOCKVP; 341 } 342 vn_close(nd->nl_open_vp, nd->nl_vp_fmode, NULL); 343 nd->nl_open_vp = NULL; 344 } 345 if (nd->nl_dvp) { 346 vrele(nd->nl_dvp); 347 nd->nl_dvp = NULL; 348 } 349 nd->nl_flags = 0; /* clear remaining flags (just clear everything) */ 350 } 351 352 /* 353 * Works similarly to nlookup_done() when nd initialized with 354 * nlookup_init_at(). 355 */ 356 void 357 nlookup_done_at(struct nlookupdata *nd, struct file *fp) 358 { 359 nlookup_done(nd); 360 if (fp != NULL) 361 fdrop(fp); 362 } 363 364 void 365 nlookup_zero(struct nlookupdata *nd) 366 { 367 bzero(nd, sizeof(struct nlookupdata)); 368 } 369 370 /* 371 * Simple all-in-one nlookup. Returns a locked namecache structure or NULL 372 * if an error occured. 373 * 374 * Note that the returned ncp is not checked for permissions, though VEXEC 375 * is checked on the directory path leading up to the result. The caller 376 * must call naccess() to check the permissions of the returned leaf. 377 */ 378 struct nchandle 379 nlookup_simple(const char *str, enum uio_seg seg, 380 int niflags, int *error) 381 { 382 struct nlookupdata nd; 383 struct nchandle nch; 384 385 *error = nlookup_init(&nd, str, seg, niflags); 386 if (*error == 0) { 387 if ((*error = nlookup(&nd)) == 0) { 388 nch = nd.nl_nch; /* keep hold ref from structure */ 389 cache_zero(&nd.nl_nch); /* and NULL out */ 390 } else { 391 cache_zero(&nch); 392 } 393 nlookup_done(&nd); 394 } else { 395 cache_zero(&nch); 396 } 397 return(nch); 398 } 399 400 /* 401 * Returns non-zero if the path element is the last element 402 */ 403 static 404 int 405 islastelement(const char *ptr) 406 { 407 while (*ptr == '/') 408 ++ptr; 409 return (*ptr == 0); 410 } 411 412 /* 413 * Returns non-zero if we need to lock the namecache element 414 * exclusively. Unless otherwise requested by NLC_SHAREDLOCK, 415 * the last element of the namecache lookup will be locked 416 * exclusively. 417 * 418 * NOTE: Even if we return on-zero, an unresolved namecache record 419 * will always be locked exclusively. 420 */ 421 static __inline 422 int 423 wantsexcllock(struct nlookupdata *nd, const char *ptr) 424 { 425 if ((nd->nl_flags & NLC_SHAREDLOCK) == 0) 426 return(islastelement(ptr)); 427 return(0); 428 } 429 430 431 /* 432 * Do a generic nlookup. Note that the passed nd is not nlookup_done()'d 433 * on return, even if an error occurs. If no error occurs or NLC_CREATE 434 * is flagged and ENOENT is returned, then the returned nl_nch is always 435 * referenced and locked exclusively. 436 * 437 * WARNING: For any general error other than ENOENT w/NLC_CREATE, the 438 * the resulting nl_nch may or may not be locked and if locked 439 * might be locked either shared or exclusive. 440 * 441 * Intermediate directory elements, including the current directory, require 442 * execute (search) permission. nlookup does not examine the access 443 * permissions on the returned element. 444 * 445 * If NLC_CREATE is set the last directory must allow node creation, 446 * and an error code of 0 will be returned for a non-existant 447 * target (not ENOENT). 448 * 449 * If NLC_RENAME_DST is set the last directory mut allow node deletion, 450 * plus the sticky check is made, and an error code of 0 will be returned 451 * for a non-existant target (not ENOENT). 452 * 453 * If NLC_DELETE is set the last directory mut allow node deletion, 454 * plus the sticky check is made. 455 * 456 * If NLC_REFDVP is set nd->nl_dvp will be set to the directory vnode 457 * of the returned entry. The vnode will be referenced, but not locked, 458 * and will be released by nlookup_done() along with everything else. 459 * 460 * NOTE: As an optimization we attempt to obtain a shared namecache lock 461 * on any intermediate elements. On success, the returned element 462 * is ALWAYS locked exclusively. 463 */ 464 int 465 nlookup(struct nlookupdata *nd) 466 { 467 globaldata_t gd = mycpu; 468 struct nlcomponent nlc; 469 struct nchandle nch; 470 struct nchandle par; 471 struct nchandle nctmp; 472 struct mount *mp; 473 struct vnode *hvp; /* hold to prevent recyclement */ 474 int wasdotordotdot; 475 char *ptr; 476 char *nptr; 477 int error; 478 int len; 479 int dflags; 480 int hit = 1; 481 int saveflag = nd->nl_flags & ~NLC_NCDIR; 482 boolean_t doretry = FALSE; 483 boolean_t inretry = FALSE; 484 485 nlookup_start: 486 #ifdef KTRACE 487 if (KTRPOINT(nd->nl_td, KTR_NAMEI)) 488 ktrnamei(nd->nl_td->td_lwp, nd->nl_path); 489 #endif 490 bzero(&nlc, sizeof(nlc)); 491 492 /* 493 * Setup for the loop. The current working namecache element is 494 * always at least referenced. We lock it as required, but always 495 * return a locked, resolved namecache entry. 496 */ 497 nd->nl_loopcnt = 0; 498 if (nd->nl_dvp) { 499 vrele(nd->nl_dvp); 500 nd->nl_dvp = NULL; 501 } 502 ptr = nd->nl_path; 503 504 /* 505 * Loop on the path components. At the top of the loop nd->nl_nch 506 * is ref'd and unlocked and represents our current position. 507 */ 508 for (;;) { 509 /* 510 * Make sure nl_nch is locked so we can access the vnode, resolution 511 * state, etc. 512 */ 513 if ((nd->nl_flags & NLC_NCPISLOCKED) == 0) { 514 nd->nl_flags |= NLC_NCPISLOCKED; 515 cache_lock_maybe_shared(&nd->nl_nch, wantsexcllock(nd, ptr)); 516 } 517 518 /* 519 * Check if the root directory should replace the current 520 * directory. This is done at the start of a translation 521 * or after a symbolic link has been found. In other cases 522 * ptr will never be pointing at a '/'. 523 */ 524 if (*ptr == '/') { 525 do { 526 ++ptr; 527 } while (*ptr == '/'); 528 cache_unlock(&nd->nl_nch); 529 cache_get_maybe_shared(&nd->nl_rootnch, &nch, 530 wantsexcllock(nd, ptr)); 531 if (nd->nl_flags & NLC_NCDIR) { 532 cache_drop_ncdir(&nd->nl_nch); 533 nd->nl_flags &= ~NLC_NCDIR; 534 } else { 535 cache_drop(&nd->nl_nch); 536 } 537 nd->nl_nch = nch; /* remains locked */ 538 539 /* 540 * Fast-track termination. There is no parent directory of 541 * the root in the same mount from the point of view of 542 * the caller so return EACCES if NLC_REFDVP is specified, 543 * and EEXIST if NLC_CREATE is also specified. 544 * e.g. 'rmdir /' or 'mkdir /' are not allowed. 545 */ 546 if (*ptr == 0) { 547 if (nd->nl_flags & NLC_REFDVP) 548 error = (nd->nl_flags & NLC_CREATE) ? EEXIST : EACCES; 549 else 550 error = 0; 551 break; 552 } 553 continue; 554 } 555 556 /* 557 * Pre-calculate next path component so we can check whether the 558 * current component directory is the last directory in the path 559 * or not. 560 */ 561 for (nptr = ptr; *nptr && *nptr != '/'; ++nptr) 562 ; 563 564 /* 565 * Check directory search permissions (nd->nl_nch is locked & refd). 566 * This will load dflags to obtain directory-special permissions to 567 * be checked along with the last component. 568 * 569 * We only need to pass-in &dflags for the second-to-last component. 570 * Optimize by passing-in NULL for any prior components, which may 571 * allow the code to bypass the naccess() call. 572 */ 573 dflags = 0; 574 if (*nptr == '/') 575 error = naccess(&nd->nl_nch, NLC_EXEC, nd->nl_cred, NULL); 576 else 577 error = naccess(&nd->nl_nch, NLC_EXEC, nd->nl_cred, &dflags); 578 if (error) 579 break; 580 581 /* 582 * Extract the next (or last) path component. Path components are 583 * limited to 255 characters. 584 */ 585 nlc.nlc_nameptr = ptr; 586 nlc.nlc_namelen = nptr - ptr; 587 ptr = nptr; 588 if (nlc.nlc_namelen >= 256) { 589 error = ENAMETOOLONG; 590 break; 591 } 592 593 /* 594 * Lookup the path component in the cache, creating an unresolved 595 * entry if necessary. We have to handle "." and ".." as special 596 * cases. 597 * 598 * When handling ".." we have to detect a traversal back through a 599 * mount point. If we are at the root, ".." just returns the root. 600 * 601 * When handling "." or ".." we also have to recalculate dflags 602 * since our dflags will be for some sub-directory instead of the 603 * parent dir. 604 * 605 * This subsection returns a locked, refd 'nch' unless it errors out, 606 * and an unlocked but still ref'd nd->nl_nch. 607 * 608 * The namecache topology is not allowed to be disconnected, so 609 * encountering a NULL parent will generate EINVAL. This typically 610 * occurs when a directory is removed out from under a process. 611 * 612 * WARNING! The unlocking of nd->nl_nch is sensitive code. 613 */ 614 KKASSERT(nd->nl_flags & NLC_NCPISLOCKED); 615 616 if (nlc.nlc_namelen == 1 && nlc.nlc_nameptr[0] == '.') { 617 cache_unlock(&nd->nl_nch); 618 nd->nl_flags &= ~NLC_NCPISLOCKED; 619 cache_get_maybe_shared(&nd->nl_nch, &nch, wantsexcllock(nd, ptr)); 620 wasdotordotdot = 1; 621 } else if (nlc.nlc_namelen == 2 && 622 nlc.nlc_nameptr[0] == '.' && nlc.nlc_nameptr[1] == '.') { 623 if (nd->nl_nch.mount == nd->nl_rootnch.mount && 624 nd->nl_nch.ncp == nd->nl_rootnch.ncp 625 ) { 626 /* 627 * ".." at the root returns the root 628 */ 629 cache_unlock(&nd->nl_nch); 630 nd->nl_flags &= ~NLC_NCPISLOCKED; 631 cache_get_maybe_shared(&nd->nl_nch, &nch, 632 wantsexcllock(nd, ptr)); 633 } else { 634 /* 635 * Locate the parent ncp. If we are at the root of a 636 * filesystem mount we have to skip to the mounted-on 637 * point in the underlying filesystem. 638 * 639 * Expect the parent to always be good since the 640 * mountpoint doesn't go away. XXX hack. cache_get() 641 * requires the ncp to already have a ref as a safety. 642 * 643 * However, a process which has been broken out of a chroot 644 * will wind up with a NULL parent if it tries to '..' above 645 * the real root, deal with the case. Note that this does 646 * not protect us from a jail breakout, it just stops a panic 647 * if the jail-broken process tries to '..' past the real 648 * root. 649 */ 650 nctmp = nd->nl_nch; 651 while (nctmp.ncp == nctmp.mount->mnt_ncmountpt.ncp) { 652 nctmp = nctmp.mount->mnt_ncmounton; 653 if (nctmp.ncp == NULL) 654 break; 655 } 656 if (nctmp.ncp == NULL) { 657 if (curthread->td_proc) { 658 kprintf("vfs_nlookup: '..' traverse broke " 659 "jail: pid %d (%s)\n", 660 curthread->td_proc->p_pid, 661 curthread->td_comm); 662 } 663 nctmp = nd->nl_rootnch; 664 } else { 665 nctmp.ncp = nctmp.ncp->nc_parent; 666 } 667 cache_hold(&nctmp); 668 cache_unlock(&nd->nl_nch); 669 nd->nl_flags &= ~NLC_NCPISLOCKED; 670 cache_get_maybe_shared(&nctmp, &nch, wantsexcllock(nd, ptr)); 671 cache_drop(&nctmp); /* NOTE: zero's nctmp */ 672 } 673 wasdotordotdot = 2; 674 } else { 675 /* 676 * Must unlock nl_nch when traversing down the path. However, 677 * the child ncp has not yet been found/created and the parent's 678 * child list might be empty. Thus releasing the lock can 679 * allow a race whereby the parent ncp's vnode is recycled. 680 * This case can occur especially when maxvnodes is set very low. 681 * 682 * We need the parent's ncp to remain resolved for all normal 683 * filesystem activities, so we vhold() the vp during the lookup 684 * to prevent recyclement due to vnlru / maxvnodes. 685 * 686 * If we race an unlink or rename the ncp might be marked 687 * DESTROYED after resolution, requiring a retry. 688 */ 689 if ((hvp = nd->nl_nch.ncp->nc_vp) != NULL) 690 vhold(hvp); 691 cache_unlock(&nd->nl_nch); 692 nd->nl_flags &= ~NLC_NCPISLOCKED; 693 error = cache_nlookup_maybe_shared(&nd->nl_nch, &nlc, 694 wantsexcllock(nd, ptr), &nch); 695 if (error == EWOULDBLOCK) { 696 nch = cache_nlookup(&nd->nl_nch, &nlc); 697 if (nch.ncp->nc_flag & NCF_UNRESOLVED) 698 hit = 0; 699 for (;;) { 700 error = cache_resolve(&nch, nd->nl_cred); 701 if (error != EAGAIN && 702 (nch.ncp->nc_flag & NCF_DESTROYED) == 0) { 703 if (error == ESTALE) { 704 if (!inretry) 705 error = ENOENT; 706 doretry = TRUE; 707 } 708 break; 709 } 710 kprintf("[diagnostic] nlookup: relookup %*.*s\n", 711 nch.ncp->nc_nlen, nch.ncp->nc_nlen, 712 nch.ncp->nc_name); 713 cache_put(&nch); 714 nch = cache_nlookup(&nd->nl_nch, &nlc); 715 } 716 } 717 if (hvp) 718 vdrop(hvp); 719 wasdotordotdot = 0; 720 } 721 722 /* 723 * If the last component was "." or ".." our dflags no longer 724 * represents the parent directory and we have to explicitly 725 * look it up. 726 * 727 * Expect the parent to be good since nch is locked. 728 */ 729 if (wasdotordotdot && error == 0) { 730 dflags = 0; 731 if ((par.ncp = nch.ncp->nc_parent) != NULL) { 732 par.mount = nch.mount; 733 cache_hold(&par); 734 cache_lock_maybe_shared(&par, wantsexcllock(nd, ptr)); 735 error = naccess(&par, 0, nd->nl_cred, &dflags); 736 cache_put(&par); 737 } 738 } 739 740 /* 741 * [end of subsection] 742 * 743 * nch is locked and referenced. 744 * nd->nl_nch is unlocked and referenced. 745 * 746 * nl_nch must be unlocked or we could chain lock to the root 747 * if a resolve gets stuck (e.g. in NFS). 748 */ 749 KKASSERT((nd->nl_flags & NLC_NCPISLOCKED) == 0); 750 751 /* 752 * Resolve the namespace if necessary. The ncp returned by 753 * cache_nlookup() is referenced and locked. 754 * 755 * XXX neither '.' nor '..' should return EAGAIN since they were 756 * previously resolved and thus cannot be newly created ncp's. 757 */ 758 if (nch.ncp->nc_flag & NCF_UNRESOLVED) { 759 hit = 0; 760 error = cache_resolve(&nch, nd->nl_cred); 761 if (error == ESTALE) { 762 if (!inretry) 763 error = ENOENT; 764 doretry = TRUE; 765 } 766 KKASSERT(error != EAGAIN); 767 } else { 768 error = nch.ncp->nc_error; 769 } 770 771 /* 772 * Early completion. ENOENT is not an error if this is the last 773 * component and NLC_CREATE or NLC_RENAME (rename target) was 774 * requested. Note that ncp->nc_error is left as ENOENT in that 775 * case, which we check later on. 776 * 777 * Also handle invalid '.' or '..' components terminating a path 778 * for a create/rename/delete. The standard requires this and pax 779 * pretty stupidly depends on it. 780 */ 781 if (islastelement(ptr)) { 782 if (error == ENOENT && 783 (nd->nl_flags & (NLC_CREATE | NLC_RENAME_DST)) 784 ) { 785 if (nd->nl_flags & NLC_NFS_RDONLY) { 786 error = EROFS; 787 } else { 788 error = naccess(&nch, nd->nl_flags | dflags, 789 nd->nl_cred, NULL); 790 } 791 } 792 if (error == 0 && wasdotordotdot && 793 (nd->nl_flags & (NLC_CREATE | NLC_DELETE | 794 NLC_RENAME_SRC | NLC_RENAME_DST))) { 795 /* 796 * POSIX junk 797 */ 798 if (nd->nl_flags & NLC_CREATE) 799 error = EEXIST; 800 else if (nd->nl_flags & NLC_DELETE) 801 error = (wasdotordotdot == 1) ? EINVAL : ENOTEMPTY; 802 else 803 error = EINVAL; 804 } 805 } 806 807 /* 808 * Early completion on error. 809 */ 810 if (error) { 811 cache_put(&nch); 812 break; 813 } 814 815 /* 816 * If the element is a symlink and it is either not the last 817 * element or it is the last element and we are allowed to 818 * follow symlinks, resolve the symlink. 819 */ 820 if ((nch.ncp->nc_flag & NCF_ISSYMLINK) && 821 (*ptr || (nd->nl_flags & NLC_FOLLOW)) 822 ) { 823 if (nd->nl_loopcnt++ >= MAXSYMLINKS) { 824 error = ELOOP; 825 cache_put(&nch); 826 break; 827 } 828 error = nreadsymlink(nd, &nch, &nlc); 829 cache_put(&nch); 830 if (error) 831 break; 832 833 /* 834 * Concatenate trailing path elements onto the returned symlink. 835 * Note that if the path component (ptr) is not exhausted, it 836 * will being with a '/', so we do not have to add another one. 837 * 838 * The symlink may not be empty. 839 */ 840 len = strlen(ptr); 841 if (nlc.nlc_namelen == 0 || nlc.nlc_namelen + len >= MAXPATHLEN) { 842 error = nlc.nlc_namelen ? ENAMETOOLONG : ENOENT; 843 objcache_put(namei_oc, nlc.nlc_nameptr); 844 break; 845 } 846 bcopy(ptr, nlc.nlc_nameptr + nlc.nlc_namelen, len + 1); 847 if (nd->nl_flags & NLC_HASBUF) 848 objcache_put(namei_oc, nd->nl_path); 849 nd->nl_path = nlc.nlc_nameptr; 850 nd->nl_flags |= NLC_HASBUF; 851 ptr = nd->nl_path; 852 853 /* 854 * Go back up to the top to resolve any initial '/'s in the 855 * symlink. 856 */ 857 continue; 858 } 859 860 /* 861 * If the element is a directory and we are crossing a mount point, 862 * Locate the mount. 863 */ 864 while ((nch.ncp->nc_flag & NCF_ISMOUNTPT) && 865 (nd->nl_flags & NLC_NOCROSSMOUNT) == 0 && 866 (mp = cache_findmount(&nch)) != NULL 867 ) { 868 struct vnode *tdp; 869 int vfs_do_busy = 0; 870 871 /* 872 * VFS must be busied before the namecache entry is locked, 873 * but we don't want to waste time calling vfs_busy() if the 874 * mount point is already resolved. 875 */ 876 again: 877 cache_put(&nch); 878 if (vfs_do_busy) { 879 while (vfs_busy(mp, 0)) { 880 if (mp->mnt_kern_flag & MNTK_UNMOUNT) { 881 kprintf("nlookup: warning umount race avoided\n"); 882 cache_dropmount(mp); 883 error = EBUSY; 884 vfs_do_busy = 0; 885 goto double_break; 886 } 887 } 888 } 889 cache_get_maybe_shared(&mp->mnt_ncmountpt, &nch, 890 wantsexcllock(nd, ptr)); 891 892 if (nch.ncp->nc_flag & NCF_UNRESOLVED) { 893 if (vfs_do_busy == 0) { 894 vfs_do_busy = 1; 895 goto again; 896 } 897 error = VFS_ROOT(mp, &tdp); 898 vfs_unbusy(mp); 899 vfs_do_busy = 0; 900 if (error) { 901 cache_dropmount(mp); 902 break; 903 } 904 cache_setvp(&nch, tdp); 905 vput(tdp); 906 } 907 if (vfs_do_busy) 908 vfs_unbusy(mp); 909 cache_dropmount(mp); 910 } 911 912 if (error) { 913 cache_put(&nch); 914 double_break: 915 break; 916 } 917 918 /* 919 * Skip any slashes to get to the next element. If there 920 * are any slashes at all the current element must be a 921 * directory or, in the create case, intended to become a directory. 922 * If it isn't we break without incrementing ptr and fall through 923 * to the failure case below. 924 */ 925 while (*ptr == '/') { 926 if ((nch.ncp->nc_flag & NCF_ISDIR) == 0 && 927 !(nd->nl_flags & NLC_WILLBEDIR) 928 ) { 929 break; 930 } 931 ++ptr; 932 } 933 934 /* 935 * Continuation case: additional elements and the current 936 * element is a directory. 937 */ 938 if (*ptr && (nch.ncp->nc_flag & NCF_ISDIR)) { 939 if (nd->nl_flags & NLC_NCDIR) { 940 cache_drop_ncdir(&nd->nl_nch); 941 nd->nl_flags &= ~NLC_NCDIR; 942 } else { 943 cache_drop(&nd->nl_nch); 944 } 945 cache_unlock(&nch); 946 KKASSERT((nd->nl_flags & NLC_NCPISLOCKED) == 0); 947 nd->nl_nch = nch; 948 continue; 949 } 950 951 /* 952 * Failure case: additional elements and the current element 953 * is not a directory 954 */ 955 if (*ptr) { 956 cache_put(&nch); 957 error = ENOTDIR; 958 break; 959 } 960 961 /* 962 * Successful lookup of last element. 963 * 964 * Check permissions if the target exists. If the target does not 965 * exist directory permissions were already tested in the early 966 * completion code above. 967 * 968 * nd->nl_flags will be adjusted on return with NLC_APPENDONLY 969 * if the file is marked append-only, and NLC_STICKY if the directory 970 * containing the file is sticky. 971 */ 972 if (nch.ncp->nc_vp && (nd->nl_flags & NLC_ALLCHKS)) { 973 error = naccess(&nch, nd->nl_flags | dflags, 974 nd->nl_cred, NULL); 975 if (error) { 976 cache_put(&nch); 977 break; 978 } 979 } 980 981 /* 982 * Termination: no more elements. 983 * 984 * If NLC_REFDVP is set acquire a referenced parent dvp. 985 */ 986 if (nd->nl_flags & NLC_REFDVP) { 987 cache_lock(&nd->nl_nch); 988 error = cache_vref(&nd->nl_nch, nd->nl_cred, &nd->nl_dvp); 989 cache_unlock(&nd->nl_nch); 990 if (error) { 991 kprintf("NLC_REFDVP: Cannot ref dvp of %p\n", nch.ncp); 992 cache_put(&nch); 993 break; 994 } 995 } 996 if (nd->nl_flags & NLC_NCDIR) { 997 cache_drop_ncdir(&nd->nl_nch); 998 nd->nl_flags &= ~NLC_NCDIR; 999 } else { 1000 cache_drop(&nd->nl_nch); 1001 } 1002 nd->nl_nch = nch; 1003 nd->nl_flags |= NLC_NCPISLOCKED; 1004 error = 0; 1005 break; 1006 } 1007 1008 if (hit) 1009 ++gd->gd_nchstats->ncs_longhits; 1010 else 1011 ++gd->gd_nchstats->ncs_longmiss; 1012 1013 if (nd->nl_flags & NLC_NCPISLOCKED) 1014 KKASSERT(cache_lockstatus(&nd->nl_nch) > 0); 1015 1016 /* 1017 * Retry the whole thing if doretry flag is set, but only once. 1018 * autofs(5) may mount another filesystem under its root directory 1019 * while resolving a path. 1020 */ 1021 if (doretry && !inretry) { 1022 inretry = TRUE; 1023 nd->nl_flags &= NLC_NCDIR; 1024 nd->nl_flags |= saveflag; 1025 goto nlookup_start; 1026 } 1027 1028 /* 1029 * NOTE: If NLC_CREATE was set the ncp may represent a negative hit 1030 * (ncp->nc_error will be ENOENT), but we will still return an error 1031 * code of 0. 1032 */ 1033 return(error); 1034 } 1035 1036 /* 1037 * Resolve a mount point's glue ncp. This ncp connects creates the illusion 1038 * of continuity in the namecache tree by connecting the ncp related to the 1039 * vnode under the mount to the ncp related to the mount's root vnode. 1040 * 1041 * If no error occured a locked, ref'd ncp is stored in *ncpp. 1042 */ 1043 int 1044 nlookup_mp(struct mount *mp, struct nchandle *nch) 1045 { 1046 struct vnode *vp; 1047 int error; 1048 1049 error = 0; 1050 cache_get(&mp->mnt_ncmountpt, nch); 1051 if (nch->ncp->nc_flag & NCF_UNRESOLVED) { 1052 while (vfs_busy(mp, 0)) 1053 ; 1054 error = VFS_ROOT(mp, &vp); 1055 vfs_unbusy(mp); 1056 if (error) { 1057 cache_put(nch); 1058 } else { 1059 cache_setvp(nch, vp); 1060 vput(vp); 1061 } 1062 } 1063 return(error); 1064 } 1065 1066 /* 1067 * Read the contents of a symlink, allocate a path buffer out of the 1068 * namei_oc and initialize the supplied nlcomponent with the result. 1069 * 1070 * If an error occurs no buffer will be allocated or returned in the nlc. 1071 */ 1072 int 1073 nreadsymlink(struct nlookupdata *nd, struct nchandle *nch, 1074 struct nlcomponent *nlc) 1075 { 1076 struct vnode *vp; 1077 struct iovec aiov; 1078 struct uio auio; 1079 int linklen; 1080 int error; 1081 char *cp; 1082 1083 nlc->nlc_nameptr = NULL; 1084 nlc->nlc_namelen = 0; 1085 if (nch->ncp->nc_vp == NULL) 1086 return(ENOENT); 1087 if ((error = cache_vget(nch, nd->nl_cred, LK_SHARED, &vp)) != 0) 1088 return(error); 1089 cp = objcache_get(namei_oc, M_WAITOK); 1090 aiov.iov_base = cp; 1091 aiov.iov_len = MAXPATHLEN; 1092 auio.uio_iov = &aiov; 1093 auio.uio_iovcnt = 1; 1094 auio.uio_offset = 0; 1095 auio.uio_rw = UIO_READ; 1096 auio.uio_segflg = UIO_SYSSPACE; 1097 auio.uio_td = nd->nl_td; 1098 auio.uio_resid = MAXPATHLEN - 1; 1099 error = VOP_READLINK(vp, &auio, nd->nl_cred); 1100 if (error) 1101 goto fail; 1102 linklen = MAXPATHLEN - 1 - auio.uio_resid; 1103 if (varsym_enable) { 1104 linklen = varsymreplace(cp, linklen, MAXPATHLEN - 1); 1105 if (linklen < 0) { 1106 error = ENAMETOOLONG; 1107 goto fail; 1108 } 1109 } 1110 cp[linklen] = 0; 1111 nlc->nlc_nameptr = cp; 1112 nlc->nlc_namelen = linklen; 1113 vput(vp); 1114 return(0); 1115 fail: 1116 objcache_put(namei_oc, cp); 1117 vput(vp); 1118 return(error); 1119 } 1120 1121 /* 1122 * Check access [XXX cache vattr!] [XXX quota] 1123 * 1124 * Generally check the NLC_* access bits. All specified bits must pass 1125 * for this function to return 0. 1126 * 1127 * The file does not have to exist when checking NLC_CREATE or NLC_RENAME_DST 1128 * access, otherwise it must exist. No error is returned in this case. 1129 * 1130 * The file must not exist if NLC_EXCL is specified. 1131 * 1132 * Directory permissions in general are tested for NLC_CREATE if the file 1133 * does not exist, NLC_DELETE if the file does exist, and NLC_RENAME_DST 1134 * whether the file exists or not. 1135 * 1136 * The directory sticky bit is tested for NLC_DELETE and NLC_RENAME_DST, 1137 * the latter is only tested if the target exists. 1138 * 1139 * The passed ncp must be referenced and locked. If it is already resolved 1140 * it may be locked shared but otherwise should be locked exclusively. 1141 */ 1142 1143 #define S_WXOK_MASK (S_IRUSR|S_IXUSR|S_IRGRP|S_IXGRP|S_IROTH|S_IXOTH) 1144 1145 static int 1146 naccess(struct nchandle *nch, int nflags, struct ucred *cred, int *nflagsp) 1147 { 1148 struct vnode *vp; 1149 struct vattr va; 1150 struct namecache *ncp; 1151 int error; 1152 int cflags; 1153 1154 KKASSERT(cache_lockstatus(nch) > 0); 1155 1156 ncp = nch->ncp; 1157 if (ncp->nc_flag & NCF_UNRESOLVED) { 1158 cache_resolve(nch, cred); 1159 ncp = nch->ncp; 1160 } 1161 error = ncp->nc_error; 1162 1163 /* 1164 * Directory permissions checks. Silently ignore ENOENT if these 1165 * tests pass. It isn't an error. 1166 * 1167 * We can safely resolve ncp->nc_parent because ncp is currently 1168 * locked. 1169 */ 1170 if (nflags & (NLC_CREATE | NLC_DELETE | NLC_RENAME_SRC | NLC_RENAME_DST)) { 1171 if (((nflags & NLC_CREATE) && ncp->nc_vp == NULL) || 1172 ((nflags & NLC_DELETE) && ncp->nc_vp != NULL) || 1173 ((nflags & NLC_RENAME_SRC) && ncp->nc_vp != NULL) || 1174 (nflags & NLC_RENAME_DST) 1175 ) { 1176 struct nchandle par; 1177 1178 if ((par.ncp = ncp->nc_parent) == NULL) { 1179 if (error != EAGAIN) 1180 error = EINVAL; 1181 } else if (error == 0 || error == ENOENT) { 1182 par.mount = nch->mount; 1183 cache_hold(&par); 1184 cache_lock_maybe_shared(&par, 0); 1185 error = naccess(&par, NLC_WRITE, cred, NULL); 1186 cache_put(&par); 1187 } 1188 } 1189 } 1190 1191 /* 1192 * NLC_EXCL check. Target file must not exist. 1193 */ 1194 if (error == 0 && (nflags & NLC_EXCL) && ncp->nc_vp != NULL) 1195 error = EEXIST; 1196 1197 /* 1198 * Try to short-cut the vnode operation for intermediate directory 1199 * components. This is a major SMP win because it avoids having 1200 * to execute a lot of code for intermediate directory components, 1201 * including shared refs and locks on intermediate directory vnodes. 1202 * 1203 * We can only do this if the caller does not need nflagsp. 1204 */ 1205 if (error == 0 && nflagsp == NULL && 1206 nflags == NLC_EXEC && (ncp->nc_flag & NCF_WXOK)) { 1207 return 0; 1208 } 1209 1210 /* 1211 * Get the vnode attributes so we can do the rest of our checks. 1212 * 1213 * NOTE: We only call naccess_va() if the target exists. 1214 */ 1215 if (error == 0) { 1216 error = cache_vget(nch, cred, LK_SHARED, &vp); 1217 if (error == ENOENT) { 1218 /* 1219 * Silently zero-out ENOENT if creating or renaming 1220 * (rename target). It isn't an error. 1221 */ 1222 if (nflags & (NLC_CREATE | NLC_RENAME_DST)) 1223 error = 0; 1224 } else if (error == 0) { 1225 /* 1226 * Get the vnode attributes and check for illegal O_TRUNC 1227 * requests and read-only mounts. 1228 * 1229 * NOTE: You can still open devices on read-only mounts for 1230 * writing. 1231 * 1232 * NOTE: creates/deletes/renames are handled by the NLC_WRITE 1233 * check on the parent directory above. 1234 * 1235 * XXX cache the va in the namecache or in the vnode 1236 */ 1237 error = VOP_GETATTR(vp, &va); 1238 if (error == 0 && (nflags & NLC_TRUNCATE)) { 1239 switch(va.va_type) { 1240 case VREG: 1241 case VDATABASE: 1242 case VCHR: 1243 case VBLK: 1244 case VFIFO: 1245 break; 1246 case VDIR: 1247 error = EISDIR; 1248 break; 1249 default: 1250 error = EINVAL; 1251 break; 1252 } 1253 } 1254 if (error == 0 && (nflags & NLC_WRITE) && vp->v_mount && 1255 (vp->v_mount->mnt_flag & MNT_RDONLY) 1256 ) { 1257 switch(va.va_type) { 1258 case VDIR: 1259 case VLNK: 1260 case VREG: 1261 case VDATABASE: 1262 error = EROFS; 1263 break; 1264 default: 1265 break; 1266 } 1267 } 1268 vput(vp); 1269 1270 /* 1271 * Check permissions based on file attributes. The passed 1272 * flags (*nflagsp) are modified with feedback based on 1273 * special attributes and requirements. 1274 */ 1275 if (error == 0) { 1276 /* 1277 * Adjust the returned (*nflagsp) if non-NULL. 1278 */ 1279 if (nflagsp) { 1280 if ((va.va_mode & VSVTX) && va.va_uid != cred->cr_uid) 1281 *nflagsp |= NLC_STICKY; 1282 if (va.va_flags & APPEND) 1283 *nflagsp |= NLC_APPENDONLY; 1284 if (va.va_flags & IMMUTABLE) 1285 *nflagsp |= NLC_IMMUTABLE; 1286 } 1287 1288 /* 1289 * NCF_WXOK can be set for world-searchable directories. 1290 * 1291 * XXX When we implement capabilities this code would also 1292 * need a cap check, or only set the flag if there are no 1293 * capabilities. 1294 */ 1295 cflags = 0; 1296 if (va.va_type == VDIR && 1297 (va.va_mode & S_WXOK_MASK) == S_WXOK_MASK) { 1298 cflags |= NCF_WXOK; 1299 } 1300 1301 /* 1302 * Track swapcache management flags in the namecache. 1303 * 1304 * Calculate the flags based on the current vattr info 1305 * and recalculate the inherited flags from the parent 1306 * (the original cache linkage may have occurred without 1307 * getattrs and thus have stale flags). 1308 */ 1309 if (va.va_flags & SF_NOCACHE) 1310 cflags |= NCF_SF_NOCACHE; 1311 if (va.va_flags & UF_CACHE) 1312 cflags |= NCF_UF_CACHE; 1313 if (ncp->nc_parent) { 1314 if (ncp->nc_parent->nc_flag & 1315 (NCF_SF_NOCACHE | NCF_SF_PNOCACHE)) { 1316 cflags |= NCF_SF_PNOCACHE; 1317 } 1318 if (ncp->nc_parent->nc_flag & 1319 (NCF_UF_CACHE | NCF_UF_PCACHE)) { 1320 cflags |= NCF_UF_PCACHE; 1321 } 1322 } 1323 1324 /* 1325 * We're not supposed to update nc_flag when holding a shared 1326 * lock, but we allow the case for certain flags. Note that 1327 * holding an exclusive lock allows updating nc_flag without 1328 * atomics. nc_flag is not allowe to be updated at all unless 1329 * a shared or exclusive lock is held. 1330 */ 1331 atomic_clear_short(&ncp->nc_flag, 1332 (NCF_SF_NOCACHE | NCF_UF_CACHE | 1333 NCF_SF_PNOCACHE | NCF_UF_PCACHE | 1334 NCF_WXOK) & ~cflags); 1335 atomic_set_short(&ncp->nc_flag, cflags); 1336 1337 /* 1338 * Process general access. 1339 */ 1340 error = naccess_va(&va, nflags, cred); 1341 } 1342 } 1343 } 1344 return(error); 1345 } 1346 1347 /* 1348 * Check the requested access against the given vattr using cred. 1349 */ 1350 int 1351 naccess_va(struct vattr *va, int nflags, struct ucred *cred) 1352 { 1353 int i; 1354 int vmode; 1355 1356 /* 1357 * Test the immutable bit. Creations, deletions, renames (source 1358 * or destination) are not allowed. chown/chmod/other is also not 1359 * allowed but is handled by SETATTR. Hardlinks to the immutable 1360 * file are allowed. 1361 * 1362 * If the directory is set to immutable then creations, deletions, 1363 * renames (source or dest) and hardlinks to files within the directory 1364 * are not allowed, and regular files opened through the directory may 1365 * not be written to or truncated (unless a special device). 1366 * 1367 * NOTE! New hardlinks to immutable files work but new hardlinks to 1368 * files, immutable or not, sitting inside an immutable directory are 1369 * not allowed. As always if the file is hardlinked via some other 1370 * path additional hardlinks may be possible even if the file is marked 1371 * immutable. The sysop needs to create a closure by checking the hard 1372 * link count. Once closure is achieved you are good, and security 1373 * scripts should check link counts anyway. 1374 * 1375 * Writes and truncations are only allowed on special devices. 1376 */ 1377 if ((va->va_flags & IMMUTABLE) || (nflags & NLC_IMMUTABLE)) { 1378 if ((nflags & NLC_IMMUTABLE) && (nflags & NLC_HLINK)) 1379 return (EPERM); 1380 if (nflags & (NLC_CREATE | NLC_DELETE | 1381 NLC_RENAME_SRC | NLC_RENAME_DST)) { 1382 return (EPERM); 1383 } 1384 if (nflags & (NLC_WRITE | NLC_TRUNCATE)) { 1385 switch(va->va_type) { 1386 case VDIR: 1387 return (EISDIR); 1388 case VLNK: 1389 case VREG: 1390 case VDATABASE: 1391 return (EPERM); 1392 default: 1393 break; 1394 } 1395 } 1396 } 1397 1398 /* 1399 * Test the no-unlink and append-only bits for opens, rename targets, 1400 * and deletions. These bits are not tested for creations or 1401 * rename sources. 1402 * 1403 * Unlike FreeBSD we allow a file with APPEND set to be renamed. 1404 * If you do not wish this you must also set NOUNLINK. 1405 * 1406 * If the governing directory is marked APPEND-only it implies 1407 * NOUNLINK for all entries in the directory. 1408 */ 1409 if (((va->va_flags & NOUNLINK) || (nflags & NLC_APPENDONLY)) && 1410 (nflags & (NLC_DELETE | NLC_RENAME_SRC | NLC_RENAME_DST)) 1411 ) { 1412 return (EPERM); 1413 } 1414 1415 /* 1416 * A file marked append-only may not be deleted but can be renamed. 1417 */ 1418 if ((va->va_flags & APPEND) && 1419 (nflags & (NLC_DELETE | NLC_RENAME_DST)) 1420 ) { 1421 return (EPERM); 1422 } 1423 1424 /* 1425 * A file marked append-only which is opened for writing must also 1426 * be opened O_APPEND. 1427 */ 1428 if ((va->va_flags & APPEND) && (nflags & (NLC_OPEN | NLC_TRUNCATE))) { 1429 if (nflags & NLC_TRUNCATE) 1430 return (EPERM); 1431 if ((nflags & (NLC_OPEN | NLC_WRITE)) == (NLC_OPEN | NLC_WRITE)) { 1432 if ((nflags & NLC_APPEND) == 0) 1433 return (EPERM); 1434 } 1435 } 1436 1437 /* 1438 * root gets universal access 1439 */ 1440 if (cred->cr_uid == 0) 1441 return(0); 1442 1443 /* 1444 * Check owner perms. 1445 * 1446 * If NLC_OWN is set the owner of the file is allowed no matter when 1447 * the owner-mode bits say (utimes). 1448 */ 1449 vmode = 0; 1450 if (nflags & NLC_READ) 1451 vmode |= S_IRUSR; 1452 if (nflags & NLC_WRITE) 1453 vmode |= S_IWUSR; 1454 if (nflags & NLC_EXEC) 1455 vmode |= S_IXUSR; 1456 1457 if (cred->cr_uid == va->va_uid) { 1458 if ((nflags & NLC_OWN) == 0) { 1459 if ((vmode & va->va_mode) != vmode) 1460 return(EACCES); 1461 } 1462 return(0); 1463 } 1464 1465 /* 1466 * If NLC_STICKY is set only the owner may delete or rename a file. 1467 * This bit is typically set on /tmp. 1468 * 1469 * Note that the NLC_READ/WRITE/EXEC bits are not typically set in 1470 * the specific delete or rename case. For deletions and renames we 1471 * usually just care about directory permissions, not file permissions. 1472 */ 1473 if ((nflags & NLC_STICKY) && 1474 (nflags & (NLC_RENAME_SRC | NLC_RENAME_DST | NLC_DELETE))) { 1475 return(EACCES); 1476 } 1477 1478 /* 1479 * Check group perms 1480 */ 1481 vmode >>= 3; 1482 for (i = 0; i < cred->cr_ngroups; ++i) { 1483 if (va->va_gid == cred->cr_groups[i]) { 1484 if ((vmode & va->va_mode) != vmode) 1485 return(EACCES); 1486 return(0); 1487 } 1488 } 1489 1490 /* 1491 * Check world perms 1492 */ 1493 vmode >>= 3; 1494 if ((vmode & va->va_mode) != vmode) 1495 return(EACCES); 1496 return(0); 1497 } 1498 1499 /* 1500 * Long-term (10-second interval) statistics collection 1501 */ 1502 static 1503 uint64_t 1504 collect_nlookup_callback(int n) 1505 { 1506 static uint64_t last_total; 1507 uint64_t save; 1508 uint64_t total; 1509 1510 total = 0; 1511 for (n = 0; n < ncpus; ++n) { 1512 globaldata_t gd = globaldata_find(n); 1513 struct nchstats *sp; 1514 1515 if ((sp = gd->gd_nchstats) != NULL) 1516 total += sp->ncs_longhits + sp->ncs_longmiss; 1517 } 1518 save = total; 1519 total = total - last_total; 1520 last_total = save; 1521 1522 return total; 1523 } 1524 1525 static 1526 void 1527 nlookup_collect_init(void *dummy __unused) 1528 { 1529 kcollect_register(KCOLLECT_NLOOKUP, "nlookup", collect_nlookup_callback, 1530 KCOLLECT_SCALE(KCOLLECT_NLOOKUP_FORMAT, 0)); 1531 } 1532 SYSINIT(collect_nlookup, SI_SUB_PROP, SI_ORDER_ANY, nlookup_collect_init, 0); 1533