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
34 * $DragonFly: src/sys/kern/vfs_nlookup.c,v 1.25 2008/07/19 04:43:33 dillon Exp $
37 * nlookup() is the 'new' namei interface. Rather then return directory and
38 * leaf vnodes (in various lock states) the new interface instead deals in
39 * namecache records. Namecache records may represent both a positive or
40 * a negative hit. The namespace is locked via the namecache record instead
41 * of via the vnode, and only the leaf namecache record (representing the
42 * filename) needs to be locked.
44 * This greatly improves filesystem parallelism and is a huge simplification
45 * of the API verses the old vnode locking / namei scheme.
47 * Filesystems must actively control the caching aspects of the namecache,
48 * and since namecache pointers are used as handles they are non-optional
49 * even for filesystems which do not generally wish to cache things. It is
50 * intended that a separate cache coherency API will be constructed to handle
54 #include "opt_ktrace.h"
56 #include <sys/param.h>
57 #include <sys/systm.h>
58 #include <sys/kernel.h>
59 #include <sys/vnode.h>
60 #include <sys/mount.h>
61 #include <sys/filedesc.h>
63 #include <sys/namei.h>
64 #include <sys/nlookup.h>
65 #include <sys/malloc.h>
67 #include <sys/objcache.h>
71 #include <sys/ktrace.h>
75 * Initialize a nlookup() structure, early error return for copyin faults
76 * or a degenerate empty string (which is not allowed).
78 * The first process proc0's credentials are used if the calling thread
79 * is not associated with a process context.
82 nlookup_init(struct nlookupdata
*nd
,
83 const char *path
, enum uio_seg seg
, int flags
)
94 * note: the pathlen set by copy*str() includes the terminating \0.
96 bzero(nd
, sizeof(struct nlookupdata
));
97 nd
->nl_path
= objcache_get(namei_oc
, M_WAITOK
);
98 nd
->nl_flags
|= NLC_HASBUF
;
99 if (seg
== UIO_SYSSPACE
)
100 error
= copystr(path
, nd
->nl_path
, MAXPATHLEN
, &pathlen
);
102 error
= copyinstr(path
, nd
->nl_path
, MAXPATHLEN
, &pathlen
);
105 * Don't allow empty pathnames.
106 * POSIX.1 requirement: "" is not a vaild file name.
108 if (error
== 0 && pathlen
<= 1)
113 cache_copy(&p
->p_fd
->fd_ncdir
, &nd
->nl_nch
);
114 cache_copy(&p
->p_fd
->fd_nrdir
, &nd
->nl_rootnch
);
115 if (p
->p_fd
->fd_njdir
.ncp
)
116 cache_copy(&p
->p_fd
->fd_njdir
, &nd
->nl_jailnch
);
117 nd
->nl_cred
= crhold(p
->p_ucred
);
119 cache_copy(&rootnch
, &nd
->nl_nch
);
120 cache_copy(&nd
->nl_nch
, &nd
->nl_rootnch
);
121 cache_copy(&nd
->nl_nch
, &nd
->nl_jailnch
);
122 nd
->nl_cred
= crhold(proc0
.p_ucred
);
125 nd
->nl_flags
|= flags
;
134 * nlookup_init() for "at" family of syscalls.
136 * Works similarly to nlookup_init() but if path is relative and fd is not
137 * AT_FDCWD, path is interpreted relative to the directory pointed to by fd.
138 * In this case, the file entry pointed to by fd is ref'ed and returned in
141 * If the call succeeds, nlookup_done_at() must be called to clean-up the nd
142 * and release the ref to the file entry.
145 nlookup_init_at(struct nlookupdata
*nd
, struct file
**fpp
, int fd
,
146 const char *path
, enum uio_seg seg
, int flags
)
148 struct thread
*td
= curthread
;
149 struct proc
*p
= td
->td_proc
;
156 if ((error
= nlookup_init(nd
, path
, seg
, flags
)) != 0) {
160 if (nd
->nl_path
[0] != '/' && fd
!= AT_FDCWD
) {
161 if ((error
= holdvnode(p
->p_fd
, fd
, &fp
)) != 0)
163 vp
= (struct vnode
*)fp
->f_data
;
164 if (vp
->v_type
!= VDIR
|| fp
->f_nchandle
.ncp
== NULL
) {
170 cache_drop(&nd
->nl_nch
);
171 cache_copy(&fp
->f_nchandle
, &nd
->nl_nch
);
184 * This works similarly to nlookup_init() but does not assume a process
185 * context. rootnch is always chosen for the root directory and the cred
186 * and starting directory are supplied in arguments.
189 nlookup_init_raw(struct nlookupdata
*nd
,
190 const char *path
, enum uio_seg seg
, int flags
,
191 struct ucred
*cred
, struct nchandle
*ncstart
)
199 bzero(nd
, sizeof(struct nlookupdata
));
200 nd
->nl_path
= objcache_get(namei_oc
, M_WAITOK
);
201 nd
->nl_flags
|= NLC_HASBUF
;
202 if (seg
== UIO_SYSSPACE
)
203 error
= copystr(path
, nd
->nl_path
, MAXPATHLEN
, &pathlen
);
205 error
= copyinstr(path
, nd
->nl_path
, MAXPATHLEN
, &pathlen
);
208 * Don't allow empty pathnames.
209 * POSIX.1 requirement: "" is not a vaild file name.
211 if (error
== 0 && pathlen
<= 1)
215 cache_copy(ncstart
, &nd
->nl_nch
);
216 cache_copy(&rootnch
, &nd
->nl_rootnch
);
217 cache_copy(&rootnch
, &nd
->nl_jailnch
);
218 nd
->nl_cred
= crhold(cred
);
220 nd
->nl_flags
|= flags
;
228 * Set a different credential; this credential will be used by future
229 * operations performed on nd.nl_open_vp and nlookupdata structure.
232 nlookup_set_cred(struct nlookupdata
*nd
, struct ucred
*cred
)
234 KKASSERT(nd
->nl_cred
!= NULL
);
236 if (nd
->nl_cred
!= cred
) {
244 * Cleanup a nlookupdata structure after we are through with it. This may
245 * be called on any nlookupdata structure initialized with nlookup_init().
246 * Calling nlookup_done() is mandatory in all cases except where nlookup_init()
247 * returns an error, even if as a consumer you believe you have taken all
248 * dynamic elements out of the nlookupdata structure.
251 nlookup_done(struct nlookupdata
*nd
)
253 if (nd
->nl_nch
.ncp
) {
254 if (nd
->nl_flags
& NLC_NCPISLOCKED
) {
255 nd
->nl_flags
&= ~NLC_NCPISLOCKED
;
256 cache_unlock(&nd
->nl_nch
);
258 cache_drop(&nd
->nl_nch
);
260 if (nd
->nl_rootnch
.ncp
)
261 cache_drop(&nd
->nl_rootnch
);
262 if (nd
->nl_jailnch
.ncp
)
263 cache_drop(&nd
->nl_jailnch
);
264 if ((nd
->nl_flags
& NLC_HASBUF
) && nd
->nl_path
) {
265 objcache_put(namei_oc
, nd
->nl_path
);
272 if (nd
->nl_open_vp
) {
273 if (nd
->nl_flags
& NLC_LOCKVP
) {
274 vn_unlock(nd
->nl_open_vp
);
275 nd
->nl_flags
&= ~NLC_LOCKVP
;
277 vn_close(nd
->nl_open_vp
, nd
->nl_vp_fmode
);
278 nd
->nl_open_vp
= NULL
;
284 nd
->nl_flags
= 0; /* clear remaining flags (just clear everything) */
288 * Works similarly to nlookup_done() when nd initialized with
292 nlookup_done_at(struct nlookupdata
*nd
, struct file
*fp
)
300 nlookup_zero(struct nlookupdata
*nd
)
302 bzero(nd
, sizeof(struct nlookupdata
));
306 * Simple all-in-one nlookup. Returns a locked namecache structure or NULL
307 * if an error occured.
309 * Note that the returned ncp is not checked for permissions, though VEXEC
310 * is checked on the directory path leading up to the result. The caller
311 * must call naccess() to check the permissions of the returned leaf.
314 nlookup_simple(const char *str
, enum uio_seg seg
,
315 int niflags
, int *error
)
317 struct nlookupdata nd
;
320 *error
= nlookup_init(&nd
, str
, seg
, niflags
);
322 if ((*error
= nlookup(&nd
)) == 0) {
323 nch
= nd
.nl_nch
; /* keep hold ref from structure */
324 cache_zero(&nd
.nl_nch
); /* and NULL out */
336 * Do a generic nlookup. Note that the passed nd is not nlookup_done()'d
337 * on return, even if an error occurs. If no error occurs the returned
338 * nl_nch is always referenced and locked, otherwise it may or may not be.
340 * Intermediate directory elements, including the current directory, require
341 * execute (search) permission. nlookup does not examine the access
342 * permissions on the returned element.
344 * If NLC_CREATE is set the last directory must allow node creation,
345 * and an error code of 0 will be returned for a non-existant
346 * target (not ENOENT).
348 * If NLC_RENAME_DST is set the last directory mut allow node deletion,
349 * plus the sticky check is made, and an error code of 0 will be returned
350 * for a non-existant target (not ENOENT).
352 * If NLC_DELETE is set the last directory mut allow node deletion,
353 * plus the sticky check is made.
355 * If NLC_REFDVP is set nd->nl_dvp will be set to the directory vnode
356 * of the returned entry. The vnode will be referenced, but not locked,
357 * and will be released by nlookup_done() along with everything else.
360 nlookup(struct nlookupdata
*nd
)
362 struct nlcomponent nlc
;
374 if (KTRPOINT(nd
->nl_td
, KTR_NAMEI
))
375 ktrnamei(nd
->nl_td
->td_lwp
, nd
->nl_path
);
377 bzero(&nlc
, sizeof(nlc
));
380 * Setup for the loop. The current working namecache element must
381 * be in a refd + unlocked state. This typically the case on entry except
382 * when stringing nlookup()'s along in a chain, since nlookup() always
383 * returns nl_nch in a locked state.
386 if (nd
->nl_flags
& NLC_NCPISLOCKED
) {
387 nd
->nl_flags
&= ~NLC_NCPISLOCKED
;
388 cache_unlock(&nd
->nl_nch
);
397 * Loop on the path components. At the top of the loop nd->nl_nch
398 * is ref'd and unlocked and represents our current position.
402 * Check if the root directory should replace the current
403 * directory. This is done at the start of a translation
404 * or after a symbolic link has been found. In other cases
405 * ptr will never be pointing at a '/'.
410 } while (*ptr
== '/');
411 cache_copy(&nd
->nl_rootnch
, &nch
);
412 cache_drop(&nd
->nl_nch
);
416 * Fast-track termination. There is no parent directory of
417 * the root in the same mount from the point of view of
418 * the caller so return EPERM if NLC_REFDVP is specified.
419 * e.g. 'rmdir /' is not allowed.
422 if (nd
->nl_flags
& NLC_REFDVP
) {
425 cache_lock(&nd
->nl_nch
);
426 nd
->nl_flags
|= NLC_NCPISLOCKED
;
435 * Check directory search permissions.
438 if ((error
= naccess(&nd
->nl_nch
, NLC_EXEC
, nd
->nl_cred
, &dflags
)) != 0)
442 * Extract the path component. Path components are limited to
445 nlc
.nlc_nameptr
= ptr
;
446 while (*ptr
&& *ptr
!= '/')
448 nlc
.nlc_namelen
= ptr
- nlc
.nlc_nameptr
;
449 if (nlc
.nlc_namelen
>= 256) {
450 error
= ENAMETOOLONG
;
455 * Lookup the path component in the cache, creating an unresolved
456 * entry if necessary. We have to handle "." and ".." as special
459 * When handling ".." we have to detect a traversal back through a
460 * mount point. If we are at the root, ".." just returns the root.
462 * When handling "." or ".." we also have to recalculate dflags
463 * since our dflags will be for some sub-directory instead of the
466 * This subsection returns a locked, refd 'nch' unless it errors out.
467 * The namecache topology is not allowed to be disconnected, so
468 * encountering a NULL parent will generate EINVAL. This typically
469 * occurs when a directory is removed out from under a process.
471 if (nlc
.nlc_namelen
== 1 && nlc
.nlc_nameptr
[0] == '.') {
472 cache_get(&nd
->nl_nch
, &nch
);
474 } else if (nlc
.nlc_namelen
== 2 &&
475 nlc
.nlc_nameptr
[0] == '.' && nlc
.nlc_nameptr
[1] == '.') {
476 if (nd
->nl_nch
.mount
== nd
->nl_rootnch
.mount
&&
477 nd
->nl_nch
.ncp
== nd
->nl_rootnch
.ncp
480 * ".." at the root returns the root
482 cache_get(&nd
->nl_nch
, &nch
);
485 * Locate the parent ncp. If we are at the root of a
486 * filesystem mount we have to skip to the mounted-on
487 * point in the underlying filesystem.
490 while (nch
.ncp
== nch
.mount
->mnt_ncmountpt
.ncp
)
491 nch
= nch
.mount
->mnt_ncmounton
;
492 nch
.ncp
= nch
.ncp
->nc_parent
;
493 KKASSERT(nch
.ncp
!= NULL
);
494 cache_get(&nch
, &nch
);
498 nch
= cache_nlookup(&nd
->nl_nch
, &nlc
);
499 while ((error
= cache_resolve(&nch
, nd
->nl_cred
)) == EAGAIN
) {
500 kprintf("[diagnostic] nlookup: relookup %*.*s\n",
501 nch
.ncp
->nc_nlen
, nch
.ncp
->nc_nlen
, nch
.ncp
->nc_name
);
503 nch
= cache_nlookup(&nd
->nl_nch
, &nlc
);
509 * If the last component was "." or ".." our dflags no longer
510 * represents the parent directory and we have to explicitly
513 if (wasdotordotdot
&& error
== 0) {
515 if ((par
.ncp
= nch
.ncp
->nc_parent
) != NULL
) {
516 par
.mount
= nch
.mount
;
519 error
= naccess(&par
, 0, nd
->nl_cred
, &dflags
);
525 * [end of subsection] ncp is locked and ref'd. nd->nl_nch is ref'd
529 * Resolve the namespace if necessary. The ncp returned by
530 * cache_nlookup() is referenced and locked.
532 * XXX neither '.' nor '..' should return EAGAIN since they were
533 * previously resolved and thus cannot be newly created ncp's.
535 if (nch
.ncp
->nc_flag
& NCF_UNRESOLVED
) {
536 error
= cache_resolve(&nch
, nd
->nl_cred
);
537 KKASSERT(error
!= EAGAIN
);
539 error
= nch
.ncp
->nc_error
;
543 * Early completion. ENOENT is not an error if this is the last
544 * component and NLC_CREATE or NLC_RENAME (rename target) was
545 * requested. Note that ncp->nc_error is left as ENOENT in that
546 * case, which we check later on.
548 * Also handle invalid '.' or '..' components terminating a path
549 * for a create/rename/delete. The standard requires this and pax
550 * pretty stupidly depends on it.
552 for (xptr
= ptr
; *xptr
== '/'; ++xptr
)
555 if (error
== ENOENT
&&
556 (nd
->nl_flags
& (NLC_CREATE
| NLC_RENAME_DST
))
558 if (nd
->nl_flags
& NLC_NFS_RDONLY
) {
561 error
= naccess(&nch
, nd
->nl_flags
| dflags
,
565 if (error
== 0 && wasdotordotdot
&&
566 (nd
->nl_flags
& (NLC_CREATE
| NLC_DELETE
|
567 NLC_RENAME_SRC
| NLC_RENAME_DST
))) {
571 if (nd
->nl_flags
& NLC_CREATE
)
573 else if (nd
->nl_flags
& NLC_DELETE
)
574 error
= (wasdotordotdot
== 1) ? EINVAL
: ENOTEMPTY
;
581 * Early completion on error.
589 * If the element is a symlink and it is either not the last
590 * element or it is the last element and we are allowed to
591 * follow symlinks, resolve the symlink.
593 if ((nch
.ncp
->nc_flag
& NCF_ISSYMLINK
) &&
594 (*ptr
|| (nd
->nl_flags
& NLC_FOLLOW
))
596 if (nd
->nl_loopcnt
++ >= MAXSYMLINKS
) {
601 error
= nreadsymlink(nd
, &nch
, &nlc
);
607 * Concatenate trailing path elements onto the returned symlink.
608 * Note that if the path component (ptr) is not exhausted, it
609 * will being with a '/', so we do not have to add another one.
611 * The symlink may not be empty.
614 if (nlc
.nlc_namelen
== 0 || nlc
.nlc_namelen
+ len
>= MAXPATHLEN
) {
615 error
= nlc
.nlc_namelen
? ENAMETOOLONG
: ENOENT
;
616 objcache_put(namei_oc
, nlc
.nlc_nameptr
);
619 bcopy(ptr
, nlc
.nlc_nameptr
+ nlc
.nlc_namelen
, len
+ 1);
620 if (nd
->nl_flags
& NLC_HASBUF
)
621 objcache_put(namei_oc
, nd
->nl_path
);
622 nd
->nl_path
= nlc
.nlc_nameptr
;
623 nd
->nl_flags
|= NLC_HASBUF
;
627 * Go back up to the top to resolve any initial '/'s in the
634 * If the element is a directory and we are crossing a mount point,
637 while ((nch
.ncp
->nc_flag
& NCF_ISMOUNTPT
) &&
638 (nd
->nl_flags
& NLC_NOCROSSMOUNT
) == 0 &&
639 (mp
= cache_findmount(&nch
)) != NULL
644 cache_get(&mp
->mnt_ncmountpt
, &nch
);
646 if (nch
.ncp
->nc_flag
& NCF_UNRESOLVED
) {
647 while (vfs_busy(mp
, 0))
649 error
= VFS_ROOT(mp
, &tdp
);
653 cache_setvp(&nch
, tdp
);
663 * Skip any slashes to get to the next element. If there
664 * are any slashes at all the current element must be a
665 * directory or, in the create case, intended to become a directory.
666 * If it isn't we break without incrementing ptr and fall through
667 * to the failure case below.
669 while (*ptr
== '/') {
670 if ((nch
.ncp
->nc_flag
& NCF_ISDIR
) == 0 &&
671 !(nd
->nl_flags
& NLC_WILLBEDIR
)
679 * Continuation case: additional elements and the current
680 * element is a directory.
682 if (*ptr
&& (nch
.ncp
->nc_flag
& NCF_ISDIR
)) {
683 cache_drop(&nd
->nl_nch
);
690 * Failure case: additional elements and the current element
700 * Successful lookup of last element.
702 * Check permissions if the target exists. If the target does not
703 * exist directory permissions were already tested in the early
704 * completion code above.
706 * nd->nl_flags will be adjusted on return with NLC_APPENDONLY
707 * if the file is marked append-only, and NLC_STICKY if the directory
708 * containing the file is sticky.
710 if (nch
.ncp
->nc_vp
&& (nd
->nl_flags
& NLC_ALLCHKS
)) {
711 error
= naccess(&nch
, nd
->nl_flags
| dflags
,
720 * Termination: no more elements.
722 * If NLC_REFDVP is set acquire a referenced parent dvp.
724 if (nd
->nl_flags
& NLC_REFDVP
) {
725 error
= cache_vref(&nd
->nl_nch
, nd
->nl_cred
, &nd
->nl_dvp
);
727 kprintf("NLC_REFDVP: Cannot ref dvp of %p\n", nch
.ncp
);
732 cache_drop(&nd
->nl_nch
);
734 nd
->nl_flags
|= NLC_NCPISLOCKED
;
740 * NOTE: If NLC_CREATE was set the ncp may represent a negative hit
741 * (ncp->nc_error will be ENOENT), but we will still return an error
748 * Resolve a mount point's glue ncp. This ncp connects creates the illusion
749 * of continuity in the namecache tree by connecting the ncp related to the
750 * vnode under the mount to the ncp related to the mount's root vnode.
752 * If no error occured a locked, ref'd ncp is stored in *ncpp.
755 nlookup_mp(struct mount
*mp
, struct nchandle
*nch
)
761 cache_get(&mp
->mnt_ncmountpt
, nch
);
762 if (nch
->ncp
->nc_flag
& NCF_UNRESOLVED
) {
763 while (vfs_busy(mp
, 0))
765 error
= VFS_ROOT(mp
, &vp
);
770 cache_setvp(nch
, vp
);
778 * Read the contents of a symlink, allocate a path buffer out of the
779 * namei_oc and initialize the supplied nlcomponent with the result.
781 * If an error occurs no buffer will be allocated or returned in the nlc.
784 nreadsymlink(struct nlookupdata
*nd
, struct nchandle
*nch
,
785 struct nlcomponent
*nlc
)
794 nlc
->nlc_nameptr
= NULL
;
795 nlc
->nlc_namelen
= 0;
796 if (nch
->ncp
->nc_vp
== NULL
)
798 if ((error
= cache_vget(nch
, nd
->nl_cred
, LK_SHARED
, &vp
)) != 0)
800 cp
= objcache_get(namei_oc
, M_WAITOK
);
802 aiov
.iov_len
= MAXPATHLEN
;
803 auio
.uio_iov
= &aiov
;
806 auio
.uio_rw
= UIO_READ
;
807 auio
.uio_segflg
= UIO_SYSSPACE
;
808 auio
.uio_td
= nd
->nl_td
;
809 auio
.uio_resid
= MAXPATHLEN
- 1;
810 error
= VOP_READLINK(vp
, &auio
, nd
->nl_cred
);
813 linklen
= MAXPATHLEN
- 1 - auio
.uio_resid
;
815 linklen
= varsymreplace(cp
, linklen
, MAXPATHLEN
- 1);
817 error
= ENAMETOOLONG
;
822 nlc
->nlc_nameptr
= cp
;
823 nlc
->nlc_namelen
= linklen
;
827 objcache_put(namei_oc
, cp
);
833 * Check access [XXX cache vattr!] [XXX quota]
835 * Generally check the NLC_* access bits. All specified bits must pass
836 * for this function to return 0.
838 * The file does not have to exist when checking NLC_CREATE or NLC_RENAME_DST
839 * access, otherwise it must exist. No error is returned in this case.
841 * The file must not exist if NLC_EXCL is specified.
843 * Directory permissions in general are tested for NLC_CREATE if the file
844 * does not exist, NLC_DELETE if the file does exist, and NLC_RENAME_DST
845 * whether the file exists or not.
847 * The directory sticky bit is tested for NLC_DELETE and NLC_RENAME_DST,
848 * the latter is only tested if the target exists.
850 * The passed ncp may or may not be locked. The caller should use a
851 * locked ncp on leaf lookups, especially for NLC_CREATE, NLC_RENAME_DST,
852 * NLC_DELETE, and NLC_EXCL checks.
855 naccess(struct nchandle
*nch
, int nflags
, struct ucred
*cred
, int *nflagsp
)
863 if (nch
->ncp
->nc_flag
& NCF_UNRESOLVED
) {
865 cache_resolve(nch
, cred
);
868 error
= nch
->ncp
->nc_error
;
871 * Directory permissions checks. Silently ignore ENOENT if these
872 * tests pass. It isn't an error.
874 if (nflags
& (NLC_CREATE
| NLC_DELETE
| NLC_RENAME_SRC
| NLC_RENAME_DST
)) {
875 if (((nflags
& NLC_CREATE
) && nch
->ncp
->nc_vp
== NULL
) ||
876 ((nflags
& NLC_DELETE
) && nch
->ncp
->nc_vp
!= NULL
) ||
877 ((nflags
& NLC_RENAME_SRC
) && nch
->ncp
->nc_vp
!= NULL
) ||
878 (nflags
& NLC_RENAME_DST
)
880 if ((par
.ncp
= nch
->ncp
->nc_parent
) == NULL
) {
883 } else if (error
== 0 || error
== ENOENT
) {
884 par
.mount
= nch
->mount
;
887 error
= naccess(&par
, NLC_WRITE
, cred
, NULL
);
894 * NLC_EXCL check. Target file must not exist.
896 if (error
== 0 && (nflags
& NLC_EXCL
) && nch
->ncp
->nc_vp
!= NULL
)
900 * Get the vnode attributes so we can do the rest of our checks.
902 * NOTE: We only call naccess_va() if the target exists.
905 error
= cache_vget(nch
, cred
, LK_SHARED
, &vp
);
906 if (error
== ENOENT
) {
908 * Silently zero-out ENOENT if creating or renaming
909 * (rename target). It isn't an error.
911 if (nflags
& (NLC_CREATE
| NLC_RENAME_DST
))
913 } else if (error
== 0) {
915 * Get the vnode attributes and check for illegal O_TRUNC
916 * requests and read-only mounts.
918 * NOTE: You can still open devices on read-only mounts for
921 * NOTE: creates/deletes/renames are handled by the NLC_WRITE
922 * check on the parent directory above.
924 * XXX cache the va in the namecache or in the vnode
926 error
= VOP_GETATTR(vp
, &va
);
927 if (error
== 0 && (nflags
& NLC_TRUNCATE
)) {
943 if (error
== 0 && (nflags
& NLC_WRITE
) && vp
->v_mount
&&
944 (vp
->v_mount
->mnt_flag
& MNT_RDONLY
)
960 * Check permissions based on file attributes. The passed
961 * flags (*nflagsp) are modified with feedback based on
962 * special attributes and requirements.
966 * Adjust the returned (*nflagsp) if non-NULL.
969 if ((va
.va_mode
& VSVTX
) && va
.va_uid
!= cred
->cr_uid
)
970 *nflagsp
|= NLC_STICKY
;
971 if (va
.va_flags
& APPEND
)
972 *nflagsp
|= NLC_APPENDONLY
;
973 if (va
.va_flags
& IMMUTABLE
)
974 *nflagsp
|= NLC_IMMUTABLE
;
978 * Process general access.
980 error
= naccess_va(&va
, nflags
, cred
);
988 * Check the requested access against the given vattr using cred.
991 naccess_va(struct vattr
*va
, int nflags
, struct ucred
*cred
)
997 * Test the immutable bit. Creations, deletions, renames (source
998 * or destination) are not allowed. chown/chmod/other is also not
999 * allowed but is handled by SETATTR. Hardlinks to the immutable
1002 * If the directory is set to immutable then creations, deletions,
1003 * renames (source or dest) and hardlinks to files within the directory
1004 * are not allowed, and regular files opened through the directory may
1005 * not be written to or truncated (unless a special device).
1007 * NOTE! New hardlinks to immutable files work but new hardlinks to
1008 * files, immutable or not, sitting inside an immutable directory are
1009 * not allowed. As always if the file is hardlinked via some other
1010 * path additional hardlinks may be possible even if the file is marked
1011 * immutable. The sysop needs to create a closure by checking the hard
1012 * link count. Once closure is achieved you are good, and security
1013 * scripts should check link counts anyway.
1015 * Writes and truncations are only allowed on special devices.
1017 if ((va
->va_flags
& IMMUTABLE
) || (nflags
& NLC_IMMUTABLE
)) {
1018 if ((nflags
& NLC_IMMUTABLE
) && (nflags
& NLC_HLINK
))
1020 if (nflags
& (NLC_CREATE
| NLC_DELETE
|
1021 NLC_RENAME_SRC
| NLC_RENAME_DST
)) {
1024 if (nflags
& (NLC_WRITE
| NLC_TRUNCATE
)) {
1025 switch(va
->va_type
) {
1039 * Test the no-unlink and append-only bits for opens, rename targets,
1040 * and deletions. These bits are not tested for creations or
1043 * Unlike FreeBSD we allow a file with APPEND set to be renamed.
1044 * If you do not wish this you must also set NOUNLINK.
1046 * If the governing directory is marked APPEND-only it implies
1047 * NOUNLINK for all entries in the directory.
1049 if (((va
->va_flags
& NOUNLINK
) || (nflags
& NLC_APPENDONLY
)) &&
1050 (nflags
& (NLC_DELETE
| NLC_RENAME_SRC
| NLC_RENAME_DST
))
1056 * A file marked append-only may not be deleted but can be renamed.
1058 if ((va
->va_flags
& APPEND
) &&
1059 (nflags
& (NLC_DELETE
| NLC_RENAME_DST
))
1065 * A file marked append-only which is opened for writing must also
1066 * be opened O_APPEND.
1068 if ((va
->va_flags
& APPEND
) && (nflags
& (NLC_OPEN
| NLC_TRUNCATE
))) {
1069 if (nflags
& NLC_TRUNCATE
)
1071 if ((nflags
& (NLC_OPEN
| NLC_WRITE
)) == (NLC_OPEN
| NLC_WRITE
)) {
1072 if ((nflags
& NLC_APPEND
) == 0)
1078 * root gets universal access
1080 if (cred
->cr_uid
== 0)
1084 * Check owner perms.
1086 * If NLC_OWN is set the owner of the file is allowed no matter when
1087 * the owner-mode bits say (utimes).
1090 if (nflags
& NLC_READ
)
1092 if (nflags
& NLC_WRITE
)
1094 if (nflags
& NLC_EXEC
)
1097 if (cred
->cr_uid
== va
->va_uid
) {
1098 if ((nflags
& NLC_OWN
) == 0) {
1099 if ((vmode
& va
->va_mode
) != vmode
)
1106 * If NLC_STICKY is set only the owner may delete or rename a file.
1107 * This bit is typically set on /tmp.
1109 * Note that the NLC_READ/WRITE/EXEC bits are not typically set in
1110 * the specific delete or rename case. For deletions and renames we
1111 * usually just care about directory permissions, not file permissions.
1113 if ((nflags
& NLC_STICKY
) &&
1114 (nflags
& (NLC_RENAME_SRC
| NLC_RENAME_DST
| NLC_DELETE
))) {
1122 for (i
= 0; i
< cred
->cr_ngroups
; ++i
) {
1123 if (va
->va_gid
== cred
->cr_groups
[i
]) {
1124 if ((vmode
& va
->va_mode
) != vmode
)
1134 if ((vmode
& va
->va_mode
) != vmode
)