2 * Copyright (c) 2004 The DragonFly Project. All rights reserved.
4 * This code is derived from software contributed to The DragonFly Project
5 * by Matthew Dillon <dillon@backplane.com>
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
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
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.
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
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.
42 * This greatly improves filesystem parallelism and is a huge simplification
43 * of the API verses the old vnode locking / namei scheme.
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
52 #include "opt_ktrace.h"
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>
61 #include <sys/namei.h>
62 #include <sys/nlookup.h>
63 #include <sys/malloc.h>
65 #include <sys/objcache.h>
69 #include <sys/ktrace.h>
72 static int naccess(struct nchandle *nch, int vmode, struct ucred *cred,
76 * Initialize a nlookup() structure, early error return for copyin faults
77 * or a degenerate empty string (which is not allowed).
79 * The first process proc0's credentials are used if the calling thread
80 * is not associated with a process context.
85 nlookup_init(struct nlookupdata *nd,
86 const char *path, enum uio_seg seg, int flags)
97 * note: the pathlen set by copy*str() includes the terminating \0.
99 bzero(nd, sizeof(struct nlookupdata));
100 nd->nl_path = objcache_get(namei_oc, M_WAITOK);
101 nd->nl_flags |= NLC_HASBUF;
102 if (seg == UIO_SYSSPACE)
103 error = copystr(path, nd->nl_path, MAXPATHLEN, &pathlen);
105 error = copyinstr(path, nd->nl_path, MAXPATHLEN, &pathlen);
108 * Don't allow empty pathnames.
109 * POSIX.1 requirement: "" is not a vaild file name.
111 if (error == 0 && pathlen <= 1)
116 cache_copy(&p->p_fd->fd_ncdir, &nd->nl_nch);
117 cache_copy(&p->p_fd->fd_nrdir, &nd->nl_rootnch);
118 if (p->p_fd->fd_njdir.ncp)
119 cache_copy(&p->p_fd->fd_njdir, &nd->nl_jailnch);
120 nd->nl_cred = crhold(p->p_ucred);
122 cache_copy(&rootnch, &nd->nl_nch);
123 cache_copy(&nd->nl_nch, &nd->nl_rootnch);
124 cache_copy(&nd->nl_nch, &nd->nl_jailnch);
125 nd->nl_cred = crhold(proc0.p_ucred);
128 nd->nl_flags |= flags;
137 * nlookup_init() for "at" family of syscalls.
139 * Works similarly to nlookup_init() but if path is relative and fd is not
140 * AT_FDCWD, path is interpreted relative to the directory pointed to by fd.
141 * In this case, the file entry pointed to by fd is ref'ed and returned in
144 * If the call succeeds, nlookup_done_at() must be called to clean-up the nd
145 * and release the ref to the file entry.
148 nlookup_init_at(struct nlookupdata *nd, struct file **fpp, int fd,
149 const char *path, enum uio_seg seg, int flags)
151 struct thread *td = curthread;
152 struct proc *p = td->td_proc;
159 if ((error = nlookup_init(nd, path, seg, flags)) != 0) {
163 if (nd->nl_path[0] != '/' && fd != AT_FDCWD) {
164 if ((error = holdvnode(p->p_fd, fd, &fp)) != 0)
166 vp = (struct vnode*)fp->f_data;
167 if (vp->v_type != VDIR || fp->f_nchandle.ncp == NULL) {
173 cache_drop(&nd->nl_nch);
174 cache_copy(&fp->f_nchandle, &nd->nl_nch);
187 * This works similarly to nlookup_init() but does not assume a process
188 * context. rootnch is always chosen for the root directory and the cred
189 * and starting directory are supplied in arguments.
192 nlookup_init_raw(struct nlookupdata *nd,
193 const char *path, enum uio_seg seg, int flags,
194 struct ucred *cred, struct nchandle *ncstart)
202 bzero(nd, sizeof(struct nlookupdata));
203 nd->nl_path = objcache_get(namei_oc, M_WAITOK);
204 nd->nl_flags |= NLC_HASBUF;
205 if (seg == UIO_SYSSPACE)
206 error = copystr(path, nd->nl_path, MAXPATHLEN, &pathlen);
208 error = copyinstr(path, nd->nl_path, MAXPATHLEN, &pathlen);
211 * Don't allow empty pathnames.
212 * POSIX.1 requirement: "" is not a vaild file name.
214 if (error == 0 && pathlen <= 1)
218 cache_copy(ncstart, &nd->nl_nch);
219 cache_copy(&rootnch, &nd->nl_rootnch);
220 cache_copy(&rootnch, &nd->nl_jailnch);
221 nd->nl_cred = crhold(cred);
223 nd->nl_flags |= flags;
231 * This works similarly to nlookup_init_raw() but does not rely
232 * on rootnch being initialized yet.
235 nlookup_init_root(struct nlookupdata *nd,
236 const char *path, enum uio_seg seg, int flags,
237 struct ucred *cred, struct nchandle *ncstart,
238 struct nchandle *ncroot)
246 bzero(nd, sizeof(struct nlookupdata));
247 nd->nl_path = objcache_get(namei_oc, M_WAITOK);
248 nd->nl_flags |= NLC_HASBUF;
249 if (seg == UIO_SYSSPACE)
250 error = copystr(path, nd->nl_path, MAXPATHLEN, &pathlen);
252 error = copyinstr(path, nd->nl_path, MAXPATHLEN, &pathlen);
255 * Don't allow empty pathnames.
256 * POSIX.1 requirement: "" is not a vaild file name.
258 if (error == 0 && pathlen <= 1)
262 cache_copy(ncstart, &nd->nl_nch);
263 cache_copy(ncroot, &nd->nl_rootnch);
264 cache_copy(ncroot, &nd->nl_jailnch);
265 nd->nl_cred = crhold(cred);
267 nd->nl_flags |= flags;
275 * Set a different credential; this credential will be used by future
276 * operations performed on nd.nl_open_vp and nlookupdata structure.
279 nlookup_set_cred(struct nlookupdata *nd, struct ucred *cred)
281 KKASSERT(nd->nl_cred != NULL);
283 if (nd->nl_cred != cred) {
291 * Cleanup a nlookupdata structure after we are through with it. This may
292 * be called on any nlookupdata structure initialized with nlookup_init().
293 * Calling nlookup_done() is mandatory in all cases except where nlookup_init()
294 * returns an error, even if as a consumer you believe you have taken all
295 * dynamic elements out of the nlookupdata structure.
298 nlookup_done(struct nlookupdata *nd)
300 if (nd->nl_nch.ncp) {
301 if (nd->nl_flags & NLC_NCPISLOCKED) {
302 nd->nl_flags &= ~NLC_NCPISLOCKED;
303 cache_unlock(&nd->nl_nch);
305 cache_drop(&nd->nl_nch); /* NULL's out the nch */
307 if (nd->nl_rootnch.ncp)
308 cache_drop(&nd->nl_rootnch);
309 if (nd->nl_jailnch.ncp)
310 cache_drop(&nd->nl_jailnch);
311 if ((nd->nl_flags & NLC_HASBUF) && nd->nl_path) {
312 objcache_put(namei_oc, nd->nl_path);
319 if (nd->nl_open_vp) {
320 if (nd->nl_flags & NLC_LOCKVP) {
321 vn_unlock(nd->nl_open_vp);
322 nd->nl_flags &= ~NLC_LOCKVP;
324 vn_close(nd->nl_open_vp, nd->nl_vp_fmode);
325 nd->nl_open_vp = NULL;
331 nd->nl_flags = 0; /* clear remaining flags (just clear everything) */
335 * Works similarly to nlookup_done() when nd initialized with
339 nlookup_done_at(struct nlookupdata *nd, struct file *fp)
347 nlookup_zero(struct nlookupdata *nd)
349 bzero(nd, sizeof(struct nlookupdata));
353 * Simple all-in-one nlookup. Returns a locked namecache structure or NULL
354 * if an error occured.
356 * Note that the returned ncp is not checked for permissions, though VEXEC
357 * is checked on the directory path leading up to the result. The caller
358 * must call naccess() to check the permissions of the returned leaf.
361 nlookup_simple(const char *str, enum uio_seg seg,
362 int niflags, int *error)
364 struct nlookupdata nd;
367 *error = nlookup_init(&nd, str, seg, niflags);
369 if ((*error = nlookup(&nd)) == 0) {
370 nch = nd.nl_nch; /* keep hold ref from structure */
371 cache_zero(&nd.nl_nch); /* and NULL out */
383 * Do a generic nlookup. Note that the passed nd is not nlookup_done()'d
384 * on return, even if an error occurs. If no error occurs the returned
385 * nl_nch is always referenced and locked, otherwise it may or may not be.
387 * Intermediate directory elements, including the current directory, require
388 * execute (search) permission. nlookup does not examine the access
389 * permissions on the returned element.
391 * If NLC_CREATE is set the last directory must allow node creation,
392 * and an error code of 0 will be returned for a non-existant
393 * target (not ENOENT).
395 * If NLC_RENAME_DST is set the last directory mut allow node deletion,
396 * plus the sticky check is made, and an error code of 0 will be returned
397 * for a non-existant target (not ENOENT).
399 * If NLC_DELETE is set the last directory mut allow node deletion,
400 * plus the sticky check is made.
402 * If NLC_REFDVP is set nd->nl_dvp will be set to the directory vnode
403 * of the returned entry. The vnode will be referenced, but not locked,
404 * and will be released by nlookup_done() along with everything else.
407 nlookup(struct nlookupdata *nd)
409 globaldata_t gd = mycpu;
410 struct nlcomponent nlc;
413 struct nchandle nctmp;
415 struct vnode *hvp; /* hold to prevent recyclement */
425 if (KTRPOINT(nd->nl_td, KTR_NAMEI))
426 ktrnamei(nd->nl_td->td_lwp, nd->nl_path);
428 bzero(&nlc, sizeof(nlc));
431 * Setup for the loop. The current working namecache element is
432 * always at least referenced. We lock it as required, but always
433 * return a locked, resolved namecache entry.
443 * Loop on the path components. At the top of the loop nd->nl_nch
444 * is ref'd and unlocked and represents our current position.
448 * Make sure nl_nch is locked so we can access the vnode, resolution
451 if ((nd->nl_flags & NLC_NCPISLOCKED) == 0) {
452 nd->nl_flags |= NLC_NCPISLOCKED;
453 cache_lock(&nd->nl_nch);
457 * Check if the root directory should replace the current
458 * directory. This is done at the start of a translation
459 * or after a symbolic link has been found. In other cases
460 * ptr will never be pointing at a '/'.
465 } while (*ptr == '/');
466 cache_get(&nd->nl_rootnch, &nch);
467 cache_put(&nd->nl_nch);
468 nd->nl_nch = nch; /* remains locked */
471 * Fast-track termination. There is no parent directory of
472 * the root in the same mount from the point of view of
473 * the caller so return EACCES if NLC_REFDVP is specified,
474 * and EEXIST if NLC_CREATE is also specified.
475 * e.g. 'rmdir /' or 'mkdir /' are not allowed.
478 if (nd->nl_flags & NLC_REFDVP)
479 error = (nd->nl_flags & NLC_CREATE) ? EEXIST : EACCES;
488 * Check directory search permissions.
491 error = naccess(&nd->nl_nch, NLC_EXEC, nd->nl_cred, &dflags);
496 * Extract the path component. Path components are limited to
499 nlc.nlc_nameptr = ptr;
500 while (*ptr && *ptr != '/')
502 nlc.nlc_namelen = ptr - nlc.nlc_nameptr;
503 if (nlc.nlc_namelen >= 256) {
504 error = ENAMETOOLONG;
509 * Lookup the path component in the cache, creating an unresolved
510 * entry if necessary. We have to handle "." and ".." as special
513 * When handling ".." we have to detect a traversal back through a
514 * mount point. If we are at the root, ".." just returns the root.
516 * When handling "." or ".." we also have to recalculate dflags
517 * since our dflags will be for some sub-directory instead of the
520 * This subsection returns a locked, refd 'nch' unless it errors out.
521 * The namecache topology is not allowed to be disconnected, so
522 * encountering a NULL parent will generate EINVAL. This typically
523 * occurs when a directory is removed out from under a process.
525 if (nlc.nlc_namelen == 1 && nlc.nlc_nameptr[0] == '.') {
526 cache_get(&nd->nl_nch, &nch);
528 } else if (nlc.nlc_namelen == 2 &&
529 nlc.nlc_nameptr[0] == '.' && nlc.nlc_nameptr[1] == '.') {
530 if (nd->nl_nch.mount == nd->nl_rootnch.mount &&
531 nd->nl_nch.ncp == nd->nl_rootnch.ncp
534 * ".." at the root returns the root
536 cache_get(&nd->nl_nch, &nch);
539 * Locate the parent ncp. If we are at the root of a
540 * filesystem mount we have to skip to the mounted-on
541 * point in the underlying filesystem.
543 * Expect the parent to always be good since the
544 * mountpoint doesn't go away. XXX hack. cache_get()
545 * requires the ncp to already have a ref as a safety.
548 while (nctmp.ncp == nctmp.mount->mnt_ncmountpt.ncp)
549 nctmp = nctmp.mount->mnt_ncmounton;
550 nctmp.ncp = nctmp.ncp->nc_parent;
551 KKASSERT(nctmp.ncp != NULL);
553 cache_get(&nctmp, &nch);
554 cache_drop(&nctmp); /* NOTE: zero's nctmp */
559 * Must unlock nl_nch when traversing down the path. However,
560 * the child ncp has not yet been found/created and the parent's
561 * child list might be empty. Thus releasing the lock can
562 * allow a race whereby the parent ncp's vnode is recycled.
563 * This case can occur especially when maxvnodes is set very low.
565 * We need the parent's ncp to remain resolved for all normal
566 * filesystem activities, so we vhold() the vp during the lookup
567 * to prevent recyclement due to vnlru / maxvnodes.
569 * If we race an unlink or rename the ncp might be marked
570 * DESTROYED after resolution, requiring a retry.
572 if ((hvp = nd->nl_nch.ncp->nc_vp) != NULL)
574 cache_unlock(&nd->nl_nch);
575 nd->nl_flags &= ~NLC_NCPISLOCKED;
576 nch = cache_nlookup(&nd->nl_nch, &nlc);
577 if (nch.ncp->nc_flag & NCF_UNRESOLVED)
579 while ((error = cache_resolve(&nch, nd->nl_cred)) == EAGAIN ||
580 (nch.ncp->nc_flag & NCF_DESTROYED)) {
581 kprintf("[diagnostic] nlookup: relookup %*.*s\n",
582 nch.ncp->nc_nlen, nch.ncp->nc_nlen, nch.ncp->nc_name);
584 nch = cache_nlookup(&nd->nl_nch, &nlc);
592 * If the last component was "." or ".." our dflags no longer
593 * represents the parent directory and we have to explicitly
596 * Expect the parent to be good since nch is locked.
598 if (wasdotordotdot && error == 0) {
600 if ((par.ncp = nch.ncp->nc_parent) != NULL) {
601 par.mount = nch.mount;
604 error = naccess(&par, 0, nd->nl_cred, &dflags);
608 if (nd->nl_flags & NLC_NCPISLOCKED) {
609 cache_unlock(&nd->nl_nch);
610 nd->nl_flags &= ~NLC_NCPISLOCKED;
614 * [end of subsection]
616 * nch is locked and referenced.
617 * nd->nl_nch is unlocked and referenced.
619 * nl_nch must be unlocked or we could chain lock to the root
620 * if a resolve gets stuck (e.g. in NFS).
624 * Resolve the namespace if necessary. The ncp returned by
625 * cache_nlookup() is referenced and locked.
627 * XXX neither '.' nor '..' should return EAGAIN since they were
628 * previously resolved and thus cannot be newly created ncp's.
630 if (nch.ncp->nc_flag & NCF_UNRESOLVED) {
632 error = cache_resolve(&nch, nd->nl_cred);
633 KKASSERT(error != EAGAIN);
635 error = nch.ncp->nc_error;
639 * Early completion. ENOENT is not an error if this is the last
640 * component and NLC_CREATE or NLC_RENAME (rename target) was
641 * requested. Note that ncp->nc_error is left as ENOENT in that
642 * case, which we check later on.
644 * Also handle invalid '.' or '..' components terminating a path
645 * for a create/rename/delete. The standard requires this and pax
646 * pretty stupidly depends on it.
648 for (xptr = ptr; *xptr == '/'; ++xptr)
651 if (error == ENOENT &&
652 (nd->nl_flags & (NLC_CREATE | NLC_RENAME_DST))
654 if (nd->nl_flags & NLC_NFS_RDONLY) {
657 error = naccess(&nch, nd->nl_flags | dflags,
661 if (error == 0 && wasdotordotdot &&
662 (nd->nl_flags & (NLC_CREATE | NLC_DELETE |
663 NLC_RENAME_SRC | NLC_RENAME_DST))) {
667 if (nd->nl_flags & NLC_CREATE)
669 else if (nd->nl_flags & NLC_DELETE)
670 error = (wasdotordotdot == 1) ? EINVAL : ENOTEMPTY;
677 * Early completion on error.
685 * If the element is a symlink and it is either not the last
686 * element or it is the last element and we are allowed to
687 * follow symlinks, resolve the symlink.
689 if ((nch.ncp->nc_flag & NCF_ISSYMLINK) &&
690 (*ptr || (nd->nl_flags & NLC_FOLLOW))
692 if (nd->nl_loopcnt++ >= MAXSYMLINKS) {
697 error = nreadsymlink(nd, &nch, &nlc);
703 * Concatenate trailing path elements onto the returned symlink.
704 * Note that if the path component (ptr) is not exhausted, it
705 * will being with a '/', so we do not have to add another one.
707 * The symlink may not be empty.
710 if (nlc.nlc_namelen == 0 || nlc.nlc_namelen + len >= MAXPATHLEN) {
711 error = nlc.nlc_namelen ? ENAMETOOLONG : ENOENT;
712 objcache_put(namei_oc, nlc.nlc_nameptr);
715 bcopy(ptr, nlc.nlc_nameptr + nlc.nlc_namelen, len + 1);
716 if (nd->nl_flags & NLC_HASBUF)
717 objcache_put(namei_oc, nd->nl_path);
718 nd->nl_path = nlc.nlc_nameptr;
719 nd->nl_flags |= NLC_HASBUF;
723 * Go back up to the top to resolve any initial '/'s in the
730 * If the element is a directory and we are crossing a mount point,
733 while ((nch.ncp->nc_flag & NCF_ISMOUNTPT) &&
734 (nd->nl_flags & NLC_NOCROSSMOUNT) == 0 &&
735 (mp = cache_findmount(&nch)) != NULL
740 cache_get(&mp->mnt_ncmountpt, &nch);
742 if (nch.ncp->nc_flag & NCF_UNRESOLVED) {
743 while (vfs_busy(mp, 0))
745 error = VFS_ROOT(mp, &tdp);
751 cache_setvp(&nch, tdp);
762 * Skip any slashes to get to the next element. If there
763 * are any slashes at all the current element must be a
764 * directory or, in the create case, intended to become a directory.
765 * If it isn't we break without incrementing ptr and fall through
766 * to the failure case below.
768 while (*ptr == '/') {
769 if ((nch.ncp->nc_flag & NCF_ISDIR) == 0 &&
770 !(nd->nl_flags & NLC_WILLBEDIR)
778 * Continuation case: additional elements and the current
779 * element is a directory.
781 if (*ptr && (nch.ncp->nc_flag & NCF_ISDIR)) {
782 cache_drop(&nd->nl_nch);
784 KKASSERT((nd->nl_flags & NLC_NCPISLOCKED) == 0);
790 * Failure case: additional elements and the current element
800 * Successful lookup of last element.
802 * Check permissions if the target exists. If the target does not
803 * exist directory permissions were already tested in the early
804 * completion code above.
806 * nd->nl_flags will be adjusted on return with NLC_APPENDONLY
807 * if the file is marked append-only, and NLC_STICKY if the directory
808 * containing the file is sticky.
810 if (nch.ncp->nc_vp && (nd->nl_flags & NLC_ALLCHKS)) {
811 error = naccess(&nch, nd->nl_flags | dflags,
820 * Termination: no more elements.
822 * If NLC_REFDVP is set acquire a referenced parent dvp.
824 if (nd->nl_flags & NLC_REFDVP) {
825 cache_lock(&nd->nl_nch);
826 error = cache_vref(&nd->nl_nch, nd->nl_cred, &nd->nl_dvp);
827 cache_unlock(&nd->nl_nch);
829 kprintf("NLC_REFDVP: Cannot ref dvp of %p\n", nch.ncp);
834 cache_drop(&nd->nl_nch);
836 nd->nl_flags |= NLC_NCPISLOCKED;
842 ++gd->gd_nchstats->ncs_longhits;
844 ++gd->gd_nchstats->ncs_longmiss;
847 * NOTE: If NLC_CREATE was set the ncp may represent a negative hit
848 * (ncp->nc_error will be ENOENT), but we will still return an error
855 * Resolve a mount point's glue ncp. This ncp connects creates the illusion
856 * of continuity in the namecache tree by connecting the ncp related to the
857 * vnode under the mount to the ncp related to the mount's root vnode.
859 * If no error occured a locked, ref'd ncp is stored in *ncpp.
862 nlookup_mp(struct mount *mp, struct nchandle *nch)
868 cache_get(&mp->mnt_ncmountpt, nch);
869 if (nch->ncp->nc_flag & NCF_UNRESOLVED) {
870 while (vfs_busy(mp, 0))
872 error = VFS_ROOT(mp, &vp);
877 cache_setvp(nch, vp);
885 * Read the contents of a symlink, allocate a path buffer out of the
886 * namei_oc and initialize the supplied nlcomponent with the result.
888 * If an error occurs no buffer will be allocated or returned in the nlc.
891 nreadsymlink(struct nlookupdata *nd, struct nchandle *nch,
892 struct nlcomponent *nlc)
901 nlc->nlc_nameptr = NULL;
902 nlc->nlc_namelen = 0;
903 if (nch->ncp->nc_vp == NULL)
905 if ((error = cache_vget(nch, nd->nl_cred, LK_SHARED, &vp)) != 0)
907 cp = objcache_get(namei_oc, M_WAITOK);
909 aiov.iov_len = MAXPATHLEN;
910 auio.uio_iov = &aiov;
913 auio.uio_rw = UIO_READ;
914 auio.uio_segflg = UIO_SYSSPACE;
915 auio.uio_td = nd->nl_td;
916 auio.uio_resid = MAXPATHLEN - 1;
917 error = VOP_READLINK(vp, &auio, nd->nl_cred);
920 linklen = MAXPATHLEN - 1 - auio.uio_resid;
922 linklen = varsymreplace(cp, linklen, MAXPATHLEN - 1);
924 error = ENAMETOOLONG;
929 nlc->nlc_nameptr = cp;
930 nlc->nlc_namelen = linklen;
934 objcache_put(namei_oc, cp);
940 * Check access [XXX cache vattr!] [XXX quota]
942 * Generally check the NLC_* access bits. All specified bits must pass
943 * for this function to return 0.
945 * The file does not have to exist when checking NLC_CREATE or NLC_RENAME_DST
946 * access, otherwise it must exist. No error is returned in this case.
948 * The file must not exist if NLC_EXCL is specified.
950 * Directory permissions in general are tested for NLC_CREATE if the file
951 * does not exist, NLC_DELETE if the file does exist, and NLC_RENAME_DST
952 * whether the file exists or not.
954 * The directory sticky bit is tested for NLC_DELETE and NLC_RENAME_DST,
955 * the latter is only tested if the target exists.
957 * The passed ncp must be referenced and locked.
960 naccess(struct nchandle *nch, int nflags, struct ucred *cred, int *nflagsp)
964 struct namecache *ncp;
968 ASSERT_NCH_LOCKED(nch);
970 if (ncp->nc_flag & NCF_UNRESOLVED) {
971 cache_resolve(nch, cred);
974 error = ncp->nc_error;
977 * Directory permissions checks. Silently ignore ENOENT if these
978 * tests pass. It isn't an error.
980 * We can safely resolve ncp->nc_parent because ncp is currently
983 if (nflags & (NLC_CREATE | NLC_DELETE | NLC_RENAME_SRC | NLC_RENAME_DST)) {
984 if (((nflags & NLC_CREATE) && ncp->nc_vp == NULL) ||
985 ((nflags & NLC_DELETE) && ncp->nc_vp != NULL) ||
986 ((nflags & NLC_RENAME_SRC) && ncp->nc_vp != NULL) ||
987 (nflags & NLC_RENAME_DST)
991 if ((par.ncp = ncp->nc_parent) == NULL) {
994 } else if (error == 0 || error == ENOENT) {
995 par.mount = nch->mount;
998 error = naccess(&par, NLC_WRITE, cred, NULL);
1005 * NLC_EXCL check. Target file must not exist.
1007 if (error == 0 && (nflags & NLC_EXCL) && ncp->nc_vp != NULL)
1011 * Get the vnode attributes so we can do the rest of our checks.
1013 * NOTE: We only call naccess_va() if the target exists.
1016 error = cache_vget(nch, cred, LK_SHARED, &vp);
1017 if (error == ENOENT) {
1019 * Silently zero-out ENOENT if creating or renaming
1020 * (rename target). It isn't an error.
1022 if (nflags & (NLC_CREATE | NLC_RENAME_DST))
1024 } else if (error == 0) {
1026 * Get the vnode attributes and check for illegal O_TRUNC
1027 * requests and read-only mounts.
1029 * NOTE: You can still open devices on read-only mounts for
1032 * NOTE: creates/deletes/renames are handled by the NLC_WRITE
1033 * check on the parent directory above.
1035 * XXX cache the va in the namecache or in the vnode
1037 error = VOP_GETATTR(vp, &va);
1038 if (error == 0 && (nflags & NLC_TRUNCATE)) {
1039 switch(va.va_type) {
1054 if (error == 0 && (nflags & NLC_WRITE) && vp->v_mount &&
1055 (vp->v_mount->mnt_flag & MNT_RDONLY)
1057 switch(va.va_type) {
1071 * Check permissions based on file attributes. The passed
1072 * flags (*nflagsp) are modified with feedback based on
1073 * special attributes and requirements.
1077 * Adjust the returned (*nflagsp) if non-NULL.
1080 if ((va.va_mode & VSVTX) && va.va_uid != cred->cr_uid)
1081 *nflagsp |= NLC_STICKY;
1082 if (va.va_flags & APPEND)
1083 *nflagsp |= NLC_APPENDONLY;
1084 if (va.va_flags & IMMUTABLE)
1085 *nflagsp |= NLC_IMMUTABLE;
1089 * Track swapcache management flags in the namecache.
1091 * Calculate the flags based on the current vattr info
1092 * and recalculate the inherited flags from the parent
1093 * (the original cache linkage may have occurred without
1094 * getattrs and thus have stale flags).
1097 if (va.va_flags & SF_NOCACHE)
1098 cflags |= NCF_SF_NOCACHE;
1099 if (va.va_flags & UF_CACHE)
1100 cflags |= NCF_UF_CACHE;
1101 if (ncp->nc_parent) {
1102 if (ncp->nc_parent->nc_flag &
1103 (NCF_SF_NOCACHE | NCF_SF_PNOCACHE)) {
1104 cflags |= NCF_SF_PNOCACHE;
1106 if (ncp->nc_parent->nc_flag &
1107 (NCF_UF_CACHE | NCF_UF_PCACHE)) {
1108 cflags |= NCF_UF_PCACHE;
1111 ncp->nc_flag &= ~(NCF_SF_NOCACHE | NCF_UF_CACHE |
1112 NCF_SF_PNOCACHE | NCF_UF_PCACHE);
1113 ncp->nc_flag |= cflags;
1116 * Process general access.
1118 error = naccess_va(&va, nflags, cred);
1126 * Check the requested access against the given vattr using cred.
1129 naccess_va(struct vattr *va, int nflags, struct ucred *cred)
1135 * Test the immutable bit. Creations, deletions, renames (source
1136 * or destination) are not allowed. chown/chmod/other is also not
1137 * allowed but is handled by SETATTR. Hardlinks to the immutable
1140 * If the directory is set to immutable then creations, deletions,
1141 * renames (source or dest) and hardlinks to files within the directory
1142 * are not allowed, and regular files opened through the directory may
1143 * not be written to or truncated (unless a special device).
1145 * NOTE! New hardlinks to immutable files work but new hardlinks to
1146 * files, immutable or not, sitting inside an immutable directory are
1147 * not allowed. As always if the file is hardlinked via some other
1148 * path additional hardlinks may be possible even if the file is marked
1149 * immutable. The sysop needs to create a closure by checking the hard
1150 * link count. Once closure is achieved you are good, and security
1151 * scripts should check link counts anyway.
1153 * Writes and truncations are only allowed on special devices.
1155 if ((va->va_flags & IMMUTABLE) || (nflags & NLC_IMMUTABLE)) {
1156 if ((nflags & NLC_IMMUTABLE) && (nflags & NLC_HLINK))
1158 if (nflags & (NLC_CREATE | NLC_DELETE |
1159 NLC_RENAME_SRC | NLC_RENAME_DST)) {
1162 if (nflags & (NLC_WRITE | NLC_TRUNCATE)) {
1163 switch(va->va_type) {
1177 * Test the no-unlink and append-only bits for opens, rename targets,
1178 * and deletions. These bits are not tested for creations or
1181 * Unlike FreeBSD we allow a file with APPEND set to be renamed.
1182 * If you do not wish this you must also set NOUNLINK.
1184 * If the governing directory is marked APPEND-only it implies
1185 * NOUNLINK for all entries in the directory.
1187 if (((va->va_flags & NOUNLINK) || (nflags & NLC_APPENDONLY)) &&
1188 (nflags & (NLC_DELETE | NLC_RENAME_SRC | NLC_RENAME_DST))
1194 * A file marked append-only may not be deleted but can be renamed.
1196 if ((va->va_flags & APPEND) &&
1197 (nflags & (NLC_DELETE | NLC_RENAME_DST))
1203 * A file marked append-only which is opened for writing must also
1204 * be opened O_APPEND.
1206 if ((va->va_flags & APPEND) && (nflags & (NLC_OPEN | NLC_TRUNCATE))) {
1207 if (nflags & NLC_TRUNCATE)
1209 if ((nflags & (NLC_OPEN | NLC_WRITE)) == (NLC_OPEN | NLC_WRITE)) {
1210 if ((nflags & NLC_APPEND) == 0)
1216 * root gets universal access
1218 if (cred->cr_uid == 0)
1222 * Check owner perms.
1224 * If NLC_OWN is set the owner of the file is allowed no matter when
1225 * the owner-mode bits say (utimes).
1228 if (nflags & NLC_READ)
1230 if (nflags & NLC_WRITE)
1232 if (nflags & NLC_EXEC)
1235 if (cred->cr_uid == va->va_uid) {
1236 if ((nflags & NLC_OWN) == 0) {
1237 if ((vmode & va->va_mode) != vmode)
1244 * If NLC_STICKY is set only the owner may delete or rename a file.
1245 * This bit is typically set on /tmp.
1247 * Note that the NLC_READ/WRITE/EXEC bits are not typically set in
1248 * the specific delete or rename case. For deletions and renames we
1249 * usually just care about directory permissions, not file permissions.
1251 if ((nflags & NLC_STICKY) &&
1252 (nflags & (NLC_RENAME_SRC | NLC_RENAME_DST | NLC_DELETE))) {
1260 for (i = 0; i < cred->cr_ngroups; ++i) {
1261 if (va->va_gid == cred->cr_groups[i]) {
1262 if ((vmode & va->va_mode) != vmode)
1272 if ((vmode & va->va_mode) != vmode)