2 * Copyright (c) 2004-2022 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>
57 #include <sys/kernel.h>
58 #include <sys/vnode.h>
59 #include <sys/mount.h>
60 #include <sys/filedesc.h>
62 #include <sys/namei.h>
63 #include <sys/nlookup.h>
64 #include <sys/malloc.h>
66 #include <sys/objcache.h>
68 #include <sys/kcollect.h>
69 #include <sys/sysctl.h>
72 #include <sys/ktrace.h>
75 __read_mostly
static int nlookup_max_retries
= 4;
76 SYSCTL_INT(_debug
, OID_AUTO
, nlookup_max_retries
, CTLFLAG_RW
,
77 &nlookup_max_retries
, 0,
78 "retries on generation mismatch");
79 __read_mostly
static int nlookup_debug
;
80 SYSCTL_INT(_debug
, OID_AUTO
, nlookup_debug
, CTLFLAG_RW
,
84 static int naccess(struct nchandle
*nch
, u_int
*genp
, int vmode
,
85 struct ucred
*cred
, int *stickyp
, int nchislocked
);
88 * unmount operations flag NLC_IGNBADDIR in order to allow the
89 * umount to successfully issue a nlookup() on the path in order
90 * to extract the mount point. Allow certain errors through.
94 keeperror(struct nlookupdata
*nd
, int error
)
97 if ((nd
->nl_flags
& NLC_IGNBADDIR
) == 0 ||
98 (error
!= EIO
&& error
!= EBADRPC
&& error
!= ESTALE
)) {
106 * Initialize a nlookup() structure, early error return for copyin faults
107 * or a degenerate empty string (which is not allowed).
109 * The first process proc0's credentials are used if the calling thread
110 * is not associated with a process context.
115 nlookup_init(struct nlookupdata
*nd
,
116 const char *path
, enum uio_seg seg
, int flags
)
127 * note: the pathlen set by copy*str() includes the terminating \0.
129 bzero(nd
, sizeof(struct nlookupdata
));
130 nd
->nl_path
= objcache_get(namei_oc
, M_WAITOK
);
131 nd
->nl_flags
|= NLC_HASBUF
;
132 if (seg
== UIO_SYSSPACE
)
133 error
= copystr(path
, nd
->nl_path
, MAXPATHLEN
, &pathlen
);
135 error
= copyinstr(path
, nd
->nl_path
, MAXPATHLEN
, &pathlen
);
138 * Don't allow empty pathnames.
139 * POSIX.1 requirement: "" is not a vaild file name.
141 if (error
== 0 && pathlen
<= 1)
146 if (nd
->nl_path
[0] == '/') {
147 if ((flags
& NLC_NLNCH_NOINIT
) == 0) {
148 nd
->nl_basench
= &p
->p_fd
->fd_nrdir
;
149 cache_copy(nd
->nl_basench
, &nd
->nl_nch
);
151 cache_copy(&p
->p_fd
->fd_nrdir
, &nd
->nl_rootnch
);
152 if (p
->p_fd
->fd_njdir
.ncp
)
153 cache_copy(&p
->p_fd
->fd_njdir
, &nd
->nl_jailnch
);
154 nd
->nl_cred
= td
->td_ucred
;
155 nd
->nl_flags
|= NLC_BORROWCRED
;
157 if ((flags
& NLC_NLNCH_NOINIT
) == 0) {
158 nd
->nl_basench
= &p
->p_fd
->fd_ncdir
;
159 cache_copy(nd
->nl_basench
, &nd
->nl_nch
);
161 cache_copy(&p
->p_fd
->fd_nrdir
, &nd
->nl_rootnch
);
162 if (p
->p_fd
->fd_njdir
.ncp
)
163 cache_copy(&p
->p_fd
->fd_njdir
, &nd
->nl_jailnch
);
164 nd
->nl_cred
= td
->td_ucred
;
165 nd
->nl_flags
|= NLC_BORROWCRED
;
168 if ((flags
& NLC_NLNCH_NOINIT
) == 0) {
169 nd
->nl_basench
= &rootnch
;
170 cache_copy(nd
->nl_basench
, &nd
->nl_nch
);
172 cache_copy(&rootnch
, &nd
->nl_rootnch
);
173 cache_copy(&rootnch
, &nd
->nl_jailnch
);
174 nd
->nl_cred
= proc0
.p_ucred
;
175 nd
->nl_flags
|= NLC_BORROWCRED
;
178 nd
->nl_flags
|= flags
& ~NLC_NLNCH_NOINIT
;
187 * nlookup_init() for "at" family of syscalls.
189 * Similar to nlookup_init() but if the path is relative and fd is not
190 * AT_FDCWD, the path will be interpreted relative to the directory pointed
191 * to by fd. In this case, the file entry pointed to by fd is ref'ed and
194 * If the call succeeds, nlookup_done_at() must be called to clean-up the nd
195 * and release the ref to the file entry.
198 nlookup_init_at(struct nlookupdata
*nd
, struct file
**fpp
, int fd
,
199 const char *path
, enum uio_seg seg
, int flags
)
201 struct thread
*td
= curthread
;
209 * Resolve the path, we might have to copy it in from userland,
210 * but don't initialize nl_basench, or nl_nch.
212 error
= nlookup_init(nd
, path
, seg
, flags
| NLC_NLNCH_NOINIT
);
213 if (__predict_false(error
))
217 * Setup nl_basench (a pointer only not refd), and copy+ref
218 * to initialize nl_nch. Only applicable to relative paths.
219 * For absolute paths, or if (fd) is degenerate, just use the
222 if (nd
->nl_path
[0] == '/') {
223 struct proc
*p
= curproc
;
224 nd
->nl_basench
= &p
->p_fd
->fd_nrdir
;
225 } else if (fd
== AT_FDCWD
) {
226 struct proc
*p
= curproc
;
227 nd
->nl_basench
= &p
->p_fd
->fd_ncdir
;
229 if ((error
= holdvnode(td
, fd
, &fp
)) != 0)
231 vp
= (struct vnode
*)fp
->f_data
;
232 if (vp
->v_type
!= VDIR
|| fp
->f_nchandle
.ncp
== NULL
) {
238 nd
->nl_basench
= &fp
->f_nchandle
;
241 cache_copy(nd
->nl_basench
, &nd
->nl_nch
);
249 * This works similarly to nlookup_init() but does not assume a process
250 * context. rootnch is always chosen for the root directory and the cred
251 * and starting directory are supplied in arguments.
254 nlookup_init_raw(struct nlookupdata
*nd
,
255 const char *path
, enum uio_seg seg
, int flags
,
256 struct ucred
*cred
, struct nchandle
*ncstart
)
264 bzero(nd
, sizeof(struct nlookupdata
));
265 nd
->nl_path
= objcache_get(namei_oc
, M_WAITOK
);
266 nd
->nl_flags
|= NLC_HASBUF
;
267 if (seg
== UIO_SYSSPACE
)
268 error
= copystr(path
, nd
->nl_path
, MAXPATHLEN
, &pathlen
);
270 error
= copyinstr(path
, nd
->nl_path
, MAXPATHLEN
, &pathlen
);
273 * Don't allow empty pathnames.
274 * POSIX.1 requirement: "" is not a vaild file name.
276 if (error
== 0 && pathlen
<= 1)
280 cache_copy(ncstart
, &nd
->nl_nch
);
281 cache_copy(&rootnch
, &nd
->nl_rootnch
);
282 cache_copy(&rootnch
, &nd
->nl_jailnch
);
283 nd
->nl_cred
= crhold(cred
);
285 nd
->nl_flags
|= flags
;
293 * This works similarly to nlookup_init_raw() but does not rely
294 * on rootnch being initialized yet.
297 nlookup_init_root(struct nlookupdata
*nd
,
298 const char *path
, enum uio_seg seg
, int flags
,
299 struct ucred
*cred
, struct nchandle
*ncstart
,
300 struct nchandle
*ncroot
)
308 bzero(nd
, sizeof(struct nlookupdata
));
309 nd
->nl_path
= objcache_get(namei_oc
, M_WAITOK
);
310 nd
->nl_flags
|= NLC_HASBUF
;
311 if (seg
== UIO_SYSSPACE
)
312 error
= copystr(path
, nd
->nl_path
, MAXPATHLEN
, &pathlen
);
314 error
= copyinstr(path
, nd
->nl_path
, MAXPATHLEN
, &pathlen
);
317 * Don't allow empty pathnames.
318 * POSIX.1 requirement: "" is not a vaild file name.
320 if (error
== 0 && pathlen
<= 1)
324 cache_copy(ncstart
, &nd
->nl_nch
);
325 cache_copy(ncroot
, &nd
->nl_rootnch
);
326 cache_copy(ncroot
, &nd
->nl_jailnch
);
327 nd
->nl_cred
= crhold(cred
);
329 nd
->nl_flags
|= flags
;
338 * Set a different credential; this credential will be used by future
339 * operations performed on nd.nl_open_vp and nlookupdata structure.
342 nlookup_set_cred(struct nlookupdata
*nd
, struct ucred
*cred
)
344 KKASSERT(nd
->nl_cred
!= NULL
);
346 if (nd
->nl_cred
!= cred
) {
348 if ((nd
->nl_flags
& NLC_BORROWCRED
) == 0)
350 nd
->nl_flags
&= ~NLC_BORROWCRED
;
357 * Cleanup a nlookupdata structure after we are through with it. This may
358 * be called on any nlookupdata structure initialized with nlookup_init().
359 * Calling nlookup_done() is mandatory in all cases except where nlookup_init()
360 * returns an error, even if as a consumer you believe you have taken all
361 * dynamic elements out of the nlookupdata structure.
364 nlookup_done(struct nlookupdata
*nd
)
366 if (nd
->nl_nch
.ncp
) {
367 if (nd
->nl_flags
& NLC_NCPISLOCKED
)
368 cache_unlock(&nd
->nl_nch
);
369 cache_drop_and_cache(&nd
->nl_nch
, nd
->nl_elmno
);
371 nd
->nl_flags
&= ~NLC_NCPISLOCKED
;
372 if (nd
->nl_rootnch
.ncp
)
373 cache_drop_and_cache(&nd
->nl_rootnch
, 0);
374 if (nd
->nl_jailnch
.ncp
)
375 cache_drop_and_cache(&nd
->nl_jailnch
, 0);
376 if ((nd
->nl_flags
& NLC_HASBUF
) && nd
->nl_path
) {
377 objcache_put(namei_oc
, nd
->nl_path
);
381 if ((nd
->nl_flags
& NLC_BORROWCRED
) == 0)
384 nd
->nl_flags
&= ~NLC_BORROWCRED
;
386 if (nd
->nl_open_vp
) {
387 if (nd
->nl_flags
& NLC_LOCKVP
) {
388 vn_unlock(nd
->nl_open_vp
);
389 nd
->nl_flags
&= ~NLC_LOCKVP
;
391 vn_close(nd
->nl_open_vp
, nd
->nl_vp_fmode
, NULL
);
392 nd
->nl_open_vp
= NULL
;
398 nd
->nl_flags
= 0; /* clear remaining flags (just clear everything) */
399 nd
->nl_basench
= NULL
;
403 * Works similarly to nlookup_done() when nd initialized with
407 nlookup_done_at(struct nlookupdata
*nd
, struct file
*fp
)
415 nlookup_zero(struct nlookupdata
*nd
)
417 bzero(nd
, sizeof(struct nlookupdata
));
421 * Simple all-in-one nlookup. Returns a locked namecache structure or NULL
422 * if an error occured.
424 * Note that the returned ncp is not checked for permissions, though VEXEC
425 * is checked on the directory path leading up to the result. The caller
426 * must call naccess() to check the permissions of the returned leaf.
429 nlookup_simple(const char *str
, enum uio_seg seg
,
430 int niflags
, int *error
)
432 struct nlookupdata nd
;
435 *error
= nlookup_init(&nd
, str
, seg
, niflags
);
437 if ((*error
= nlookup(&nd
)) == 0) {
438 nch
= nd
.nl_nch
; /* keep hold ref from structure */
439 cache_zero(&nd
.nl_nch
); /* and NULL out */
451 * Returns non-zero if the path element is the last element
455 islastelement(const char *ptr
)
463 * Returns non-zero if we need to lock the namecache element
464 * exclusively. Unless otherwise requested by NLC_SHAREDLOCK,
465 * the last element of the namecache lookup will be locked
468 * O_CREAT or O_TRUNC need the last element to be locked exlcusively.
469 * Intermediate elements are always locked shared.
471 * NOTE: Even if we return on-zero, an unresolved namecache record
472 * will always be locked exclusively.
476 wantsexcllock(struct nlookupdata
*nd
, int last_element
)
478 if ((nd
->nl_flags
& NLC_SHAREDLOCK
) == 0)
479 return(last_element
);
485 * Do a generic nlookup. Note that the passed nd is not nlookup_done()'d
486 * on return, even if an error occurs. If no error occurs or NLC_CREATE
487 * is flagged and ENOENT is returned, then the returned nl_nch is always
488 * referenced and locked exclusively.
490 * WARNING: For any general error other than ENOENT w/NLC_CREATE, the
491 * the resulting nl_nch may or may not be locked and if locked
492 * might be locked either shared or exclusive.
494 * Intermediate directory elements, including the current directory, require
495 * execute (search) permission. nlookup does not examine the access
496 * permissions on the returned element.
498 * If NLC_CREATE is set the last directory must allow node creation,
499 * and an error code of 0 will be returned for a non-existant
500 * target (not ENOENT).
502 * If NLC_RENAME_DST is set the last directory mut allow node deletion,
503 * plus the sticky check is made, and an error code of 0 will be returned
504 * for a non-existant target (not ENOENT).
506 * If NLC_DELETE is set the last directory mut allow node deletion,
507 * plus the sticky check is made.
509 * If NLC_REFDVP is set nd->nl_dvp will be set to the directory vnode
510 * of the returned entry. The vnode will be referenced but not locked.
512 * IF THE PATH REPRESENTS A MOUNT POINT CROSSING THEN NLC_REFDVP WILL SET
513 * NL_DVP TO NULL AND RETURN NO ERROR (ERROR == 0), allowing the operation
514 * to return up the stack. The nch will only be referenced and not locked.
515 * High level code must check this case and do the right thing since,
516 * typically, it means things like 'mkdir' should fail with EEXIST. For
517 * example 'mkdir /var/cache' where /var/cache is a null-mount from
518 * /build/var.cache, needs to return EEXIST rather than a mount-crossing
521 * NOTE: As an optimization we attempt to obtain a shared namecache lock
522 * on any intermediate elements. On success, the returned element
523 * is ALWAYS locked exclusively.
525 * NOTE: If for any reason the nc_generation number of the ncp's being
526 * evaluated changes, the lookup is retried.
529 nlookup(struct nlookupdata
*nd
)
531 globaldata_t gd
= mycpu
;
532 struct nlcomponent nlc
;
534 struct nchandle nctmp
;
544 int saveflag
= nd
->nl_flags
;
545 int max_retries
= nlookup_max_retries
;
549 boolean_t doretry
= FALSE
;
550 boolean_t inretry
= FALSE
;
557 if (KTRPOINT(nd
->nl_td
, KTR_NAMEI
))
558 ktrnamei(nd
->nl_td
->td_lwp
, nd
->nl_path
);
560 bzero(&nlc
, sizeof(nlc
));
563 * Setup for the loop. The current working namecache element is
564 * always at least referenced. We lock it as required, but always
565 * return a locked, resolved namecache entry.
574 nl_gen
= nd
->nl_nch
.ncp
? nd
->nl_nch
.ncp
->nc_generation
: 0;
579 * Loop on the path components. At the top of the loop nd->nl_nch
580 * is ref'd and unlocked and represents our current position.
586 KKASSERT((nd
->nl_flags
& NLC_NCPISLOCKED
) == 0);
589 * Check if the root directory should replace the current
590 * directory. This is done at the start of a translation
591 * or after a symbolic link has been found. In other cases
592 * ptr will never be pointing at a '/'.
597 } while (*ptr
== '/');
600 * We might already be at the root as a pre-optimization
602 if (nd
->nl_nch
.mount
!= nd
->nl_rootnch
.mount
||
603 nd
->nl_nch
.ncp
!= nd
->nl_rootnch
.ncp
) {
604 cache_drop_and_cache(&nd
->nl_nch
, 0);
605 cache_copy(&nd
->nl_rootnch
, &nd
->nl_nch
);
606 nl_gen
= nd
->nl_nch
.ncp
->nc_generation
& ~3;
610 * Fast-track termination. There is no parent directory of
611 * the root in the same mount from the point of view of
612 * the caller so return EACCES if NLC_REFDVP is specified,
613 * and EEXIST if NLC_CREATE is also specified.
614 * e.g. 'rmdir /' or 'mkdir /' are not allowed.
617 if (nd
->nl_flags
& NLC_REFDVP
)
618 error
= (nd
->nl_flags
& NLC_CREATE
) ? EEXIST
: EACCES
;
621 nd
->nl_flags
|= NLC_NCPISLOCKED
;
622 cache_lock_maybe_shared(&nd
->nl_nch
,
623 wantsexcllock(nd
, islastelement(ptr
)));
630 * Pre-calculate next path component so we can check whether the
631 * current component directory is the last directory in the path
634 for (nptr
= ptr
; *nptr
&& *nptr
!= '/'; ++nptr
)
638 * nd->nl_nch is referenced and not locked here.
640 * Check directory search permissions. This will load dflags to
641 * obtain directory-special permissions to be checked along with the
644 * We only need to pass-in &dflags for the second-to-last component.
645 * Optimize by passing-in NULL for any prior components, which may
646 * allow the code to bypass the naccess() call.
648 * naccess() is optimized to avoid having to lock the nch or get
649 * the related vnode if cached perms are sufficient.
652 if (*nptr
== '/' || (saveflag
& NLC_MODIFYING_MASK
) == 0) {
653 error
= naccess(&nd
->nl_nch
, &nl_gen
, NLC_EXEC
,
654 nd
->nl_cred
, NULL
, 0);
656 error
= naccess(&nd
->nl_nch
, &nl_gen
, NLC_EXEC
,
657 nd
->nl_cred
, &dflags
, 0);
660 if (keeperror(nd
, error
))
666 * Extract the next (or last) path component. Path components are
667 * limited to 255 characters.
669 nlc
.nlc_nameptr
= ptr
;
670 nlc
.nlc_namelen
= nptr
- ptr
;
672 if (nlc
.nlc_namelen
>= 256) {
673 error
= ENAMETOOLONG
;
676 last_element
= islastelement(nptr
);
679 * Lookup the path component in the cache, creating an unresolved
680 * entry if necessary. We have to handle "." and ".." as special
683 * When handling ".." we have to detect a traversal back through a
684 * mount point. If we are at the root, ".." just returns the root.
686 * When handling "." or ".." we also have to recalculate dflags
687 * since our dflags will be for some sub-directory instead of the
690 * This subsection returns a referenced and possibly locked 'nch'.
691 * The locking status is based on the last_element flag.
693 * The namecache topology is not allowed to be disconnected, so
694 * encountering a NULL parent will generate EINVAL. This typically
695 * occurs when a directory is removed out from under a process.
697 * WARNING! The unlocking of nd->nl_nch is sensitive code.
699 KKASSERT((nd
->nl_flags
& NLC_NCPISLOCKED
) == 0);
701 if (nlc
.nlc_namelen
== 1 && nlc
.nlc_nameptr
[0] == '.') {
703 cache_get_maybe_shared(&nd
->nl_nch
, &nch
,
704 wantsexcllock(nd
, 1));
706 cache_copy(&nd
->nl_nch
, &nch
);
708 nch_gen
= nch
.ncp
->nc_generation
& ~3;
710 } else if (nlc
.nlc_namelen
== 2 &&
711 nlc
.nlc_nameptr
[0] == '.' && nlc
.nlc_nameptr
[1] == '.') {
712 if (nd
->nl_nch
.mount
== nd
->nl_rootnch
.mount
&&
713 nd
->nl_nch
.ncp
== nd
->nl_rootnch
.ncp
716 * ".." at the root returns the root
719 cache_get_maybe_shared(&nd
->nl_nch
, &nch
,
720 wantsexcllock(nd
, 1));
722 cache_copy(&nd
->nl_nch
, &nch
);
726 * Locate the parent ncp. If we are at the root of a
727 * filesystem mount we have to skip to the mounted-on
728 * point in the underlying filesystem.
730 * Expect the parent to always be good since the
731 * mountpoint doesn't go away. XXX hack. cache_get()
732 * requires the ncp to already have a ref as a safety.
734 * However, a process which has been broken out of a chroot
735 * will wind up with a NULL parent if it tries to '..' above
736 * the real root, deal with the case. Note that this does
737 * not protect us from a jail breakout, it just stops a panic
738 * if the jail-broken process tries to '..' past the real
742 while (nctmp
.ncp
== nctmp
.mount
->mnt_ncmountpt
.ncp
) {
743 nctmp
= nctmp
.mount
->mnt_ncmounton
;
744 if (nctmp
.ncp
== NULL
)
747 if (nctmp
.ncp
== NULL
) {
748 if (curthread
->td_proc
) {
749 kprintf("vfs_nlookup: '..' traverse broke "
750 "jail: pid %d (%s)\n",
751 curthread
->td_proc
->p_pid
,
754 nctmp
= nd
->nl_rootnch
;
756 nctmp
.ncp
= nctmp
.ncp
->nc_parent
;
759 cache_get_maybe_shared(&nctmp
, &nch
,
760 wantsexcllock(nd
, 1));
762 cache_copy(&nctmp
, &nch
);
765 nch_gen
= nch
.ncp
->nc_generation
& ~3;
769 * Quickly lookup the component. If we can't find it, then
770 * slowly lookup and resolve the component.
773 error
= cache_nlookup_maybe_shared(&nd
->nl_nch
, &nlc
,
774 wantsexcllock(nd
, 1),
777 nch
= cache_nlookup_nonlocked(&nd
->nl_nch
, &nlc
);
783 * At this point the only possible error is EWOULDBLOCK.
785 * If no error nch is set and referenced, and then also locked
786 * according to last_element. For EWOULDBLOCK nch is not set.
787 * For any other error nch is set and referenced, but not locked.
789 * On EWOULDBLOCK the ncp may be unresolved (if not locked it can
790 * become unresolved at any time, but we don't care at this time).
792 if (error
== EWOULDBLOCK
) {
793 nch
= cache_nlookup(&nd
->nl_nch
, &nlc
);
794 if (nch
.ncp
->nc_flag
& NCF_UNRESOLVED
)
797 error
= cache_resolve(&nch
, &nch_gen
, nd
->nl_cred
);
798 if (error
!= EAGAIN
&&
799 (nch
.ncp
->nc_flag
& NCF_DESTROYED
) == 0) {
800 if (error
== ESTALE
) {
805 if (last_element
== 0)
809 kprintf("[diagnostic] nlookup: relookup %*.*s\n",
810 nch
.ncp
->nc_nlen
, nch
.ncp
->nc_nlen
,
813 nch
= cache_nlookup(&nd
->nl_nch
, &nlc
);
816 nch_gen
= nch
.ncp
->nc_generation
& ~3;
821 * If the component is "." or ".." our dflags no longer represents
822 * the parent directory and we have to explicitly look it up.
824 * Expect the parent to be good since nch is locked.
826 * nch will continue to be valid even if an error occurs after this
829 if (wasdotordotdot
&& error
== 0) {
833 if (last_element
== 0)
834 cache_lock_maybe_shared(&nch
, wantsexcllock(nd
, 0));
836 if ((par
.ncp
= nch
.ncp
->nc_parent
) != NULL
) {
839 par
.mount
= nch
.mount
;
841 error
= naccess(&par
, &dummy_gen
, 0, nd
->nl_cred
, &dflags
, 0);
842 cache_drop_and_cache(&par
, nd
->nl_elmno
- 1);
844 if (!keeperror(nd
, error
))
846 if (error
== EINVAL
) {
847 kprintf("nlookup (%s): trailing . or .. retry on %s\n",
848 curthread
->td_comm
, nd
->nl_path
);
854 if (last_element
== 0)
859 * [end of subsection]
861 * nch is referenced and locked according to (last_element).
862 * nd->nl_nch is unlocked and referenced.
863 * nl_gen and nch_gen are both set.
865 KKASSERT((nd
->nl_flags
& NLC_NCPISLOCKED
) == 0);
868 * Resolve the namespace if necessary. The ncp returned by
869 * cache_nlookup() is referenced, and also locked according
872 * XXX neither '.' nor '..' should return EAGAIN since they were
873 * previously resolved and thus cannot be newly created ncp's.
875 if (nch
.ncp
->nc_flag
& NCF_UNRESOLVED
) {
876 if (last_element
== 0)
879 error
= cache_resolve(&nch
, &nch_gen
, nd
->nl_cred
);
880 if (error
== ESTALE
) {
885 if (last_element
== 0)
887 KKASSERT(error
!= EAGAIN
);
889 error
= nch
.ncp
->nc_error
;
893 * Early completion. ENOENT is not an error if this is the last
894 * component and NLC_CREATE or NLC_RENAME (rename target) was
895 * requested. Note that ncp->nc_error is left as ENOENT in that
896 * case, which we check later on.
898 * Also handle invalid '.' or '..' components terminating a path
899 * for a create/rename/delete. The standard requires this and pax
900 * pretty stupidly depends on it.
903 if (error
== ENOENT
&&
904 (nd
->nl_flags
& (NLC_CREATE
| NLC_RENAME_DST
)))
906 if (nd
->nl_flags
& NLC_NFS_RDONLY
) {
909 error
= naccess(&nch
, &nch_gen
, nd
->nl_flags
| dflags
,
910 nd
->nl_cred
, NULL
, last_element
);
913 if (error
== 0 && wasdotordotdot
&&
914 (nd
->nl_flags
& (NLC_CREATE
| NLC_DELETE
|
915 NLC_RENAME_SRC
| NLC_RENAME_DST
)))
920 if (nd
->nl_flags
& NLC_CREATE
)
922 else if (nd
->nl_flags
& NLC_DELETE
)
923 error
= (wasdotordotdot
== 1) ? EINVAL
: ENOTEMPTY
;
930 * Early completion on error.
935 cache_drop_and_cache(&nch
, nd
->nl_elmno
);
940 * If the element is a symlink and it is either not the last
941 * element or it is the last element and we are allowed to
942 * follow symlinks, resolve the symlink.
944 if ((nch
.ncp
->nc_flag
& NCF_ISSYMLINK
) &&
945 (*ptr
|| (nd
->nl_flags
& NLC_FOLLOW
))
947 if (nd
->nl_loopcnt
++ >= MAXSYMLINKS
) {
951 cache_drop_and_cache(&nch
, nd
->nl_elmno
);
956 * Check for a generation change.
958 * NOTE: On generation changes we must at a minimum cycle
959 * the lock. Here we get or have the lock so we are
962 if (last_element
== 0)
963 cache_lock_maybe_shared(&nch
, 1);
965 if ((nch
.ncp
->nc_generation
- nch_gen
) & ~1) {
966 if (nlookup_debug
& 1) {
967 kprintf("nlookup: symlink: GEN CHANGE %d\n",
968 (nch
.ncp
->nc_generation
- nch_gen
));
973 error
= nreadsymlink(nd
, &nch
, &nlc
);
979 * Concatenate trailing path elements onto the returned symlink.
980 * Note that if the path component (ptr) is not exhausted, it
981 * will being with a '/', so we do not have to add another one.
983 * The symlink may not be empty.
986 if (nlc
.nlc_namelen
== 0 || nlc
.nlc_namelen
+ len
>= MAXPATHLEN
) {
987 error
= nlc
.nlc_namelen
? ENAMETOOLONG
: ENOENT
;
988 objcache_put(namei_oc
, nlc
.nlc_nameptr
);
991 bcopy(ptr
, nlc
.nlc_nameptr
+ nlc
.nlc_namelen
, len
+ 1);
994 if (nd
->nl_flags
& NLC_HASBUF
)
995 objcache_put(namei_oc
, nd
->nl_path
);
997 path_reset
= nd
->nl_path
;
999 nd
->nl_path
= nlc
.nlc_nameptr
;
1000 nd
->nl_flags
|= NLC_HASBUF
;
1002 /* nl_gen has not changed */
1005 * Go back up to the top to resolve any initial '/'s in the
1012 * If the element is a directory and we are crossing a mount point,
1015 while ((nch
.ncp
->nc_flag
& NCF_ISMOUNTPT
) &&
1016 (nd
->nl_flags
& NLC_NOCROSSMOUNT
) == 0 &&
1017 (mp
= cache_findmount(&nch
)) != NULL
1020 int vfs_do_busy
= 0;
1023 * VFS must be busied before the namecache entry is locked,
1024 * but we don't want to waste time calling vfs_busy() if the
1025 * mount point is already resolved.
1029 * Check for a generation change.
1031 * NOTE: On generation changes we must at a minimum cycle
1032 * the lock. So get and release the lock if we
1035 if ((nch
.ncp
->nc_generation
- nch_gen
) & ~1) {
1036 if (last_element
== 0) {
1037 cache_lock_maybe_shared(&nch
, 1);
1040 if (nlookup_debug
& 1) {
1041 kprintf("nlookup: mountpt: GEN CHANGE %d\n",
1042 (nch
.ncp
->nc_generation
- nch_gen
));
1048 cache_drop_and_cache(&nch
, nd
->nl_elmno
);
1051 while (vfs_busy(mp
, 0)) {
1052 if (mp
->mnt_kern_flag
& MNTK_UNMOUNT
) {
1053 kprintf("nlookup: warning umount race avoided\n");
1054 cache_dropmount(mp
);
1063 * We don't need to lock the nch unless the entry is unresolved
1064 * or this is the last element.
1067 cache_get_maybe_shared(&mp
->mnt_ncmountpt
, &nch
,
1068 wantsexcllock(nd
, 1));
1070 cache_copy(&mp
->mnt_ncmountpt
, &nch
);
1071 nch_gen
= nch
.ncp
->nc_generation
& ~3;
1073 if (nch
.ncp
->nc_flag
& NCF_UNRESOLVED
) {
1074 if (last_element
== 0)
1076 if (nch
.ncp
->nc_flag
& NCF_UNRESOLVED
) {
1077 if (vfs_do_busy
== 0) {
1079 if (last_element
== 0)
1083 error
= VFS_ROOT(mp
, &tdp
);
1086 if (keeperror(nd
, error
)) {
1087 cache_dropmount(mp
);
1088 if (last_element
== 0)
1093 cache_setvp(&nch
, tdp
);
1094 nch_gen
= nch
.ncp
->nc_generation
& ~3;
1098 if (last_element
== 0)
1103 cache_dropmount(mp
);
1107 * Break out on error
1109 if (keeperror(nd
, error
)) {
1112 cache_drop_and_cache(&nch
, nd
->nl_elmno
);
1118 * Skip any slashes to get to the next element. If there
1119 * are any slashes at all the current element must be a
1120 * directory or, in the create case, intended to become a directory.
1121 * If it isn't we break without incrementing ptr and fall through
1122 * to the failure case below.
1124 while (*ptr
== '/') {
1125 if ((nch
.ncp
->nc_flag
& NCF_ISDIR
) == 0 &&
1126 !(nd
->nl_flags
& NLC_WILLBEDIR
)
1134 * Continuation case: additional elements and the current
1135 * element is a directory.
1137 if (*ptr
&& (nch
.ncp
->nc_flag
& NCF_ISDIR
)) {
1139 * Check for a generation change.
1141 * NOTE: On generation changes we must at a minimum cycle
1142 * the lock. So get and release the lock if we
1145 if ((nch
.ncp
->nc_generation
- nch_gen
) & ~1) {
1146 if (last_element
== 0) {
1147 cache_lock_maybe_shared(&nch
, 1);
1150 if (nlookup_debug
& 1) {
1151 kprintf("nlookup: next: GEN CHANGE %d\n",
1152 (nch
.ncp
->nc_generation
- nch_gen
));
1156 cache_drop_and_cache(&nd
->nl_nch
, nd
->nl_elmno
);
1159 /*nchislocked = 0; not needed */
1160 KKASSERT((nd
->nl_flags
& NLC_NCPISLOCKED
) == 0);
1167 * Check for a generation change.
1169 * NOTE: On generation changes we must at a minimum cycle
1170 * the lock. So get and release the lock if we
1173 if ((nch
.ncp
->nc_generation
- nch_gen
) & ~1) {
1174 if (nlookup_debug
& 1) {
1175 if (last_element
== 0) {
1176 cache_lock_maybe_shared(&nch
, 1);
1179 kprintf("nlookup: final: GEN CHANGE %d\n",
1180 (nch
.ncp
->nc_generation
- nch_gen
));
1186 * Failure case: additional elements and the current element
1187 * is not a directory
1192 cache_drop_and_cache(&nch
, nd
->nl_elmno
);
1198 * Successful lookup of last element.
1200 * Check permissions if the target exists. If the target does not
1201 * exist directory permissions were already tested in the early
1202 * completion code above.
1204 * nd->nl_flags will be adjusted on return with NLC_APPENDONLY
1205 * if the file is marked append-only, and NLC_STICKY if the directory
1206 * containing the file is sticky.
1208 KKASSERT(last_element
);
1210 if (nch
.ncp
->nc_vp
&& (nd
->nl_flags
& NLC_ALLCHKS
)) {
1211 error
= naccess(&nch
, &nch_gen
, nd
->nl_flags
| dflags
,
1212 nd
->nl_cred
, NULL
, 1);
1213 if (keeperror(nd
, error
)) {
1220 * Termination: no more elements.
1222 * Check to see if the immediate parent has been destroyed. This race
1223 * can occur because the element lookup must temporarily unlock
1224 * the parent. If so, do a retry.
1226 if (nch
.ncp
->nc_parent
&&
1227 (nch
.ncp
->nc_parent
->nc_flag
& NCF_DESTROYED
)) {
1232 * Termination: no more elements.
1234 * If NLC_REFDVP is set acquire a referenced parent dvp. Typically
1235 * used for mkdir/mknod/ncreate/nremove/unlink/rename.
1237 * If a mount-point transition occurs due to ncp being a mount point,
1238 * or a null-mount, nl_dvp will be set to NULL and an error code of
1239 * 0 will be returned. A NULL nc_parent is not necessarily the only
1240 * indication of a mount-point as null-mounts will also tend to have
1241 * a non-null nc_parent.
1243 * nch is locked, standard lock order for the namecache is
1244 * child-to-parent so we can safely lock its parent. We can
1245 * just use cache_dvpref().
1247 if ((nd
->nl_flags
& NLC_REFDVP
) &&
1248 (doretry
== FALSE
|| inretry
== TRUE
)) {
1249 if (nch
.ncp
->nc_parent
) {
1250 error
= cache_resolve_dvp(&nch
, nd
->nl_cred
,
1253 if (nlookup_debug
& 1) {
1254 kprintf("Parent directory lost during "
1255 "nlookup: %s/%s (%08x/%08x)\n",
1256 nch
.ncp
->nc_parent
->nc_name
,
1258 nch
.ncp
->nc_parent
->nc_flag
,
1267 * Mount-point, nl_dvp should remain NULL, error 0,
1268 * caller won't be able to use the results so leave
1269 * the ncp referenced but unlocked.
1271 if (nd
->nl_dvp
== NULL
) {
1277 * Good directory, fall through to drop-and-cache
1283 * Mount-point, nl_dvp should remain NULL, error 0,
1284 * caller won't be able to use the results so leave
1285 * the ncp referenced but unlocked.
1294 * ncp left with lock+ref on break, set NLC_NCPISLOCKED flag
1296 cache_drop_and_cache(&nd
->nl_nch
, nd
->nl_elmno
);
1298 nd
->nl_flags
|= NLC_NCPISLOCKED
;
1305 * Force a retry (up to max_retries) if nl_gen is incorrect
1307 * NOTE: On generation changes we must at a minimum cycle
1308 * the lock. In this case we have one so we are ok.
1310 if (nd
->nl_nch
.ncp
&& (nd
->nl_nch
.ncp
->nc_generation
- nl_gen
) & ~1) {
1311 if (nlookup_debug
& 1) {
1312 kprintf("nlookup: DONE error %d: GEN CHANGE ON \"%s\" "
1313 "%d (retries %d)\n",
1315 nd
->nl_nch
.ncp
->nc_name
,
1316 (nd
->nl_nch
.ncp
->nc_generation
- nl_gen
),
1332 * We are done / or possibly retry
1335 ++gd
->gd_nchstats
->ncs_longhits
;
1337 ++gd
->gd_nchstats
->ncs_longmiss
;
1339 if (nd
->nl_flags
& NLC_NCPISLOCKED
)
1340 KKASSERT(cache_lockstatus(&nd
->nl_nch
) > 0);
1343 * Reset nd->nl_path if necessary (due to softlinks). We want to return
1344 * nl_path to its original state before retrying or returning.
1347 if (nd
->nl_flags
& NLC_HASBUF
) {
1348 objcache_put(namei_oc
, nd
->nl_path
);
1349 nd
->nl_flags
&= ~NLC_HASBUF
;
1351 nd
->nl_path
= path_reset
;
1352 nd
->nl_flags
|= saveflag
& NLC_HASBUF
;
1357 * Retry the whole thing if doretry flag is set, but only once.
1359 * autofs(5) may mount another filesystem under its root directory
1360 * while resolving a path.
1362 * NFS might return ESTALE
1364 if (doretry
&& !inretry
) {
1365 if (nlookup_debug
& 2)
1366 kprintf("nlookup: errno %d retry %s\n", error
, nd
->nl_path
);
1370 * Clean up nd->nl_nch and reset to base directory
1372 if (nd
->nl_flags
& NLC_NCPISLOCKED
) {
1373 cache_unlock(&nd
->nl_nch
);
1374 nd
->nl_flags
&= ~NLC_NCPISLOCKED
;
1376 cache_drop(&nd
->nl_nch
);
1377 cache_copy(nd
->nl_basench
, &nd
->nl_nch
);
1380 nd
->nl_flags
|= saveflag
;
1386 * NOTE: If NLC_CREATE was set the ncp may represent a negative hit
1387 * (ncp->nc_error will be ENOENT), but we will still return an error
1394 * Resolve a mount point's glue ncp. This ncp connects creates the illusion
1395 * of continuity in the namecache tree by connecting the ncp related to the
1396 * vnode under the mount to the ncp related to the mount's root vnode.
1398 * If no error occured a locked, ref'd ncp is stored in *ncpp.
1401 nlookup_mp(struct mount
*mp
, struct nchandle
*nch
)
1407 cache_get(&mp
->mnt_ncmountpt
, nch
);
1408 if (nch
->ncp
->nc_flag
& NCF_UNRESOLVED
) {
1409 while (vfs_busy(mp
, 0))
1411 error
= VFS_ROOT(mp
, &vp
);
1416 cache_setvp(nch
, vp
);
1424 * Read the contents of a symlink, allocate a path buffer out of the
1425 * namei_oc and initialize the supplied nlcomponent with the result.
1427 * If an error occurs no buffer will be allocated or returned in the nlc.
1430 nreadsymlink(struct nlookupdata
*nd
, struct nchandle
*nch
,
1431 struct nlcomponent
*nlc
)
1440 nlc
->nlc_nameptr
= NULL
;
1441 nlc
->nlc_namelen
= 0;
1442 if (nch
->ncp
->nc_vp
== NULL
)
1444 if ((error
= cache_vget(nch
, nd
->nl_cred
, LK_SHARED
, &vp
)) != 0)
1446 cp
= objcache_get(namei_oc
, M_WAITOK
);
1448 aiov
.iov_len
= MAXPATHLEN
;
1449 auio
.uio_iov
= &aiov
;
1450 auio
.uio_iovcnt
= 1;
1451 auio
.uio_offset
= 0;
1452 auio
.uio_rw
= UIO_READ
;
1453 auio
.uio_segflg
= UIO_SYSSPACE
;
1454 auio
.uio_td
= nd
->nl_td
;
1455 auio
.uio_resid
= MAXPATHLEN
- 1;
1456 error
= VOP_READLINK(vp
, &auio
, nd
->nl_cred
);
1459 linklen
= MAXPATHLEN
- 1 - auio
.uio_resid
;
1460 if (varsym_enable
) {
1461 linklen
= varsymreplace(cp
, linklen
, MAXPATHLEN
- 1);
1463 error
= ENAMETOOLONG
;
1468 nlc
->nlc_nameptr
= cp
;
1469 nlc
->nlc_namelen
= linklen
;
1473 objcache_put(namei_oc
, cp
);
1479 * Check access [XXX cache vattr!] [XXX quota]
1481 * Generally check the NLC_* access bits. All specified bits must pass
1482 * for this function to return 0.
1484 * The file does not have to exist when checking NLC_CREATE or NLC_RENAME_DST
1485 * access, otherwise it must exist. No error is returned in this case.
1487 * The file must not exist if NLC_EXCL is specified.
1489 * Directory permissions in general are tested for NLC_CREATE if the file
1490 * does not exist, NLC_DELETE if the file does exist, and NLC_RENAME_DST
1491 * whether the file exists or not.
1493 * The directory sticky bit is tested for NLC_DELETE and NLC_RENAME_DST,
1494 * the latter is only tested if the target exists.
1496 * The passed ncp must be referenced and locked. If it is already resolved
1497 * it may be locked shared but otherwise should be locked exclusively.
1500 #define S_WXOK_MASK (S_IRUSR|S_IXUSR|S_IRGRP|S_IXGRP|S_IROTH|S_IXOTH)
1501 #define S_XOK_MASK (S_IXUSR|S_IXGRP|S_IXOTH)
1504 naccess(struct nchandle
*nch
, u_int
*genp
, int nflags
,
1505 struct ucred
*cred
, int *nflagsp
, int nchislocked
)
1508 struct vattr_lite lva
;
1509 struct namecache
*ncp
;
1517 * We need a resolved entry. If the entry is not resolved we need
1518 * to lock and resolve it. If it is already resolved, our ref should
1519 * prevent normal evictions (as long as we tested the lock race above).
1521 * If the ncp was locked by the caller and left unresolved, it must
1522 * have been locked exclusively.
1524 if (ncp
->nc_flag
& NCF_UNRESOLVED
) {
1525 if (nchislocked
== 0) {
1529 cache_resolve(nch
, genp
, cred
);
1532 error
= ncp
->nc_error
;
1535 * Only unresolved entries should return this error (though maybe
1536 * in-filesystem sockets can too). XXX check filetype for VSOCK.
1538 if (error
== ENOTCONN
) {
1539 if (nchislocked
== 0) {
1540 if (nlookup_debug
& 4) {
1541 kprintf("ncp %p %08x %d %s: Warning, unexpected state, "
1543 ncp
, ncp
->nc_flag
, ncp
->nc_error
, ncp
->nc_name
);
1544 print_backtrace(-1);
1550 if (nlookup_debug
& 4) {
1551 kprintf("ncp %p %08x %d %s: Warning, unexpected state\n",
1552 ncp
, ncp
->nc_flag
, ncp
->nc_error
, ncp
->nc_name
);
1553 print_backtrace(-1);
1558 * Directory permissions checks. Silently ignore ENOENT if these
1559 * tests pass. It isn't an error.
1561 * We can safely resolve ncp->nc_parent because ncp is currently
1564 if (nflags
& (NLC_CREATE
| NLC_DELETE
| NLC_RENAME_SRC
| NLC_RENAME_DST
)) {
1565 if (((nflags
& NLC_CREATE
) && ncp
->nc_vp
== NULL
) ||
1566 ((nflags
& NLC_DELETE
) && ncp
->nc_vp
!= NULL
) ||
1567 ((nflags
& NLC_RENAME_SRC
) && ncp
->nc_vp
!= NULL
) ||
1568 (nflags
& NLC_RENAME_DST
)
1570 struct nchandle par
;
1572 if (nchislocked
== 0) {
1573 cache_lock_maybe_shared(nch
, 0);
1577 if ((par
.ncp
= ncp
->nc_parent
) == NULL
) {
1578 if (error
!= EAGAIN
)
1580 } else if (error
== 0 || error
== ENOENT
) {
1581 u_int dummy_gen
= 0;
1583 par
.mount
= nch
->mount
;
1585 cache_lock_maybe_shared(&par
, 0);
1586 error
= naccess(&par
, &dummy_gen
, NLC_WRITE
, cred
, NULL
, 1);
1593 * NLC_EXCL check. Target file must not exist.
1595 if (error
== 0 && (nflags
& NLC_EXCL
) && ncp
->nc_vp
!= NULL
)
1599 * Try to short-cut the vnode operation for intermediate directory
1600 * components. This is a major SMP win because it avoids having
1601 * to execute a lot of code for intermediate directory components,
1602 * including shared refs and locks on intermediate directory vnodes.
1604 * We can only do this if the caller does not need nflagsp.
1606 if (error
== 0 && nflagsp
== NULL
&&
1607 nflags
== NLC_EXEC
&& (ncp
->nc_flag
& NCF_WXOK
)) {
1608 if (nchislocked
== 2)
1614 * Get the vnode attributes so we can do the rest of our checks.
1616 * NOTE: We only call naccess_lva() if the target exists.
1619 if (nchislocked
== 0) {
1620 cache_lock_maybe_shared(nch
, 0);
1624 error
= cache_vget(nch
, cred
, LK_SHARED
, &vp
);
1626 error
= cache_vref(nch
, cred
, &vp
);
1628 if (error
== ENOENT
) {
1630 * Silently zero-out ENOENT if creating or renaming
1631 * (rename target). It isn't an error.
1633 if (nflags
& (NLC_CREATE
| NLC_RENAME_DST
))
1635 } else if (error
== 0) {
1637 * Get the vnode attributes and check for illegal O_TRUNC
1638 * requests and read-only mounts.
1640 * NOTE: You can still open devices on read-only mounts for
1643 * NOTE: creates/deletes/renames are handled by the NLC_WRITE
1644 * check on the parent directory above.
1646 * XXX cache the va in the namecache or in the vnode
1648 error
= VOP_GETATTR_LITE(vp
, &lva
);
1649 if (error
== 0 && (nflags
& NLC_TRUNCATE
)) {
1650 switch(lva
.va_type
) {
1665 if (error
== 0 && (nflags
& NLC_WRITE
) && vp
->v_mount
&&
1666 (vp
->v_mount
->mnt_flag
& MNT_RDONLY
)
1668 switch(lva
.va_type
) {
1686 * Check permissions based on file attributes. The passed
1687 * flags (*nflagsp) are modified with feedback based on
1688 * special attributes and requirements.
1692 * Adjust the returned (*nflagsp) if non-NULL.
1695 if ((lva
.va_mode
& VSVTX
) && lva
.va_uid
!= cred
->cr_uid
)
1696 *nflagsp
|= NLC_STICKY
;
1697 if (lva
.va_flags
& APPEND
)
1698 *nflagsp
|= NLC_APPENDONLY
;
1699 if (lva
.va_flags
& IMMUTABLE
)
1700 *nflagsp
|= NLC_IMMUTABLE
;
1704 * NCF_WXOK can be set for world-searchable directories.
1706 * XXX When we implement capabilities this code would also
1707 * need a cap check, or only set the flag if there are no
1711 if (lva
.va_type
== VDIR
&&
1712 (lva
.va_mode
& S_WXOK_MASK
) == S_WXOK_MASK
) {
1715 if ((lva
.va_mode
& S_XOK_MASK
) == 0)
1719 * Track swapcache management flags in the namecache.
1721 * Calculate the flags based on the current vattr_lite info
1722 * and recalculate the inherited flags from the parent
1723 * (the original cache linkage may have occurred without
1724 * getattrs and thus have stale flags).
1726 if (lva
.va_flags
& SF_NOCACHE
)
1727 cflags
|= NCF_SF_NOCACHE
;
1728 if (lva
.va_flags
& UF_CACHE
)
1729 cflags
|= NCF_UF_CACHE
;
1730 if (ncp
->nc_parent
) {
1731 if (ncp
->nc_parent
->nc_flag
&
1732 (NCF_SF_NOCACHE
| NCF_SF_PNOCACHE
)) {
1733 cflags
|= NCF_SF_PNOCACHE
;
1735 if (ncp
->nc_parent
->nc_flag
&
1736 (NCF_UF_CACHE
| NCF_UF_PCACHE
)) {
1737 cflags
|= NCF_UF_PCACHE
;
1742 * We're not supposed to update nc_flag when holding a shared
1743 * lock, but we allow the case for certain flags. Note that
1744 * holding an exclusive lock allows updating nc_flag without
1745 * atomics. nc_flag is not allowe to be updated at all unless
1746 * a shared or exclusive lock is held.
1748 atomic_clear_short(&ncp
->nc_flag
,
1749 (NCF_SF_NOCACHE
| NCF_UF_CACHE
|
1750 NCF_SF_PNOCACHE
| NCF_UF_PCACHE
|
1751 NCF_WXOK
| NCF_NOTX
) & ~cflags
);
1752 atomic_set_short(&ncp
->nc_flag
, cflags
);
1755 * Process general access.
1757 error
= naccess_lva(&lva
, nflags
, cred
);
1761 if (nchislocked
== 2)
1767 * Check the requested access against the given vattr using cred.
1770 naccess_lva(struct vattr_lite
*lvap
, int nflags
, struct ucred
*cred
)
1776 * Test the immutable bit. Creations, deletions, renames (source
1777 * or destination) are not allowed. chown/chmod/other is also not
1778 * allowed but is handled by SETATTR. Hardlinks to the immutable
1781 * If the directory is set to immutable then creations, deletions,
1782 * renames (source or dest) and hardlinks to files within the directory
1783 * are not allowed, and regular files opened through the directory may
1784 * not be written to or truncated (unless a special device).
1786 * NOTE! New hardlinks to immutable files work but new hardlinks to
1787 * files, immutable or not, sitting inside an immutable directory are
1788 * not allowed. As always if the file is hardlinked via some other
1789 * path additional hardlinks may be possible even if the file is marked
1790 * immutable. The sysop needs to create a closure by checking the hard
1791 * link count. Once closure is achieved you are good, and security
1792 * scripts should check link counts anyway.
1794 * Writes and truncations are only allowed on special devices.
1796 if ((lvap
->va_flags
& IMMUTABLE
) || (nflags
& NLC_IMMUTABLE
)) {
1797 if ((nflags
& NLC_IMMUTABLE
) && (nflags
& NLC_HLINK
))
1799 if (nflags
& (NLC_CREATE
| NLC_DELETE
|
1800 NLC_RENAME_SRC
| NLC_RENAME_DST
)) {
1803 if (nflags
& (NLC_WRITE
| NLC_TRUNCATE
)) {
1804 switch(lvap
->va_type
) {
1818 * Test the no-unlink and append-only bits for opens, rename targets,
1819 * and deletions. These bits are not tested for creations or
1822 * Unlike FreeBSD we allow a file with APPEND set to be renamed.
1823 * If you do not wish this you must also set NOUNLINK.
1825 * If the governing directory is marked APPEND-only it implies
1826 * NOUNLINK for all entries in the directory.
1828 if (((lvap
->va_flags
& NOUNLINK
) || (nflags
& NLC_APPENDONLY
)) &&
1829 (nflags
& (NLC_DELETE
| NLC_RENAME_SRC
| NLC_RENAME_DST
))
1835 * A file marked append-only may not be deleted but can be renamed.
1837 if ((lvap
->va_flags
& APPEND
) &&
1838 (nflags
& (NLC_DELETE
| NLC_RENAME_DST
))
1844 * A file marked append-only which is opened for writing must also
1845 * be opened O_APPEND.
1847 if ((lvap
->va_flags
& APPEND
) && (nflags
& (NLC_OPEN
| NLC_TRUNCATE
))) {
1848 if (nflags
& NLC_TRUNCATE
)
1850 if ((nflags
& (NLC_OPEN
| NLC_WRITE
)) == (NLC_OPEN
| NLC_WRITE
)) {
1851 if ((nflags
& NLC_APPEND
) == 0)
1857 * root gets universal access
1859 if (cred
->cr_uid
== 0)
1863 * Check owner perms.
1865 * If NLC_OWN is set the owner of the file is allowed no matter when
1866 * the owner-mode bits say (utimes).
1869 if (nflags
& NLC_READ
)
1871 if (nflags
& NLC_WRITE
)
1873 if (nflags
& NLC_EXEC
)
1876 if (cred
->cr_uid
== lvap
->va_uid
) {
1877 if ((nflags
& NLC_OWN
) == 0) {
1878 if ((vmode
& lvap
->va_mode
) != vmode
)
1885 * If NLC_STICKY is set only the owner may delete or rename a file.
1886 * This bit is typically set on /tmp.
1888 * Note that the NLC_READ/WRITE/EXEC bits are not typically set in
1889 * the specific delete or rename case. For deletions and renames we
1890 * usually just care about directory permissions, not file permissions.
1892 if ((nflags
& NLC_STICKY
) &&
1893 (nflags
& (NLC_RENAME_SRC
| NLC_RENAME_DST
| NLC_DELETE
))) {
1901 for (i
= 0; i
< cred
->cr_ngroups
; ++i
) {
1902 if (lvap
->va_gid
== cred
->cr_groups
[i
]) {
1903 if ((vmode
& lvap
->va_mode
) != vmode
)
1913 if ((vmode
& lvap
->va_mode
) != vmode
)
1919 * Long-term (10-second interval) statistics collection
1923 collect_nlookup_callback(int n
)
1925 static uint64_t last_total
;
1930 for (n
= 0; n
< ncpus
; ++n
) {
1931 globaldata_t gd
= globaldata_find(n
);
1932 struct nchstats
*sp
;
1934 if ((sp
= gd
->gd_nchstats
) != NULL
)
1935 total
+= sp
->ncs_longhits
+ sp
->ncs_longmiss
;
1938 total
= total
- last_total
;
1946 nlookup_collect_init(void *dummy __unused
)
1948 kcollect_register(KCOLLECT_NLOOKUP
, "nlookup", collect_nlookup_callback
,
1949 KCOLLECT_SCALE(KCOLLECT_NLOOKUP_FORMAT
, 0));
1951 SYSINIT(collect_nlookup
, SI_SUB_PROP
, SI_ORDER_ANY
, nlookup_collect_init
, 0);