2 * SPDX-License-Identifier: BSD-3-Clause
4 * Copyright (c) 1982, 1986, 1989, 1993
5 * The Regents of the University of California. All rights reserved.
6 * (c) UNIX System Laboratories, Inc.
7 * All or some portions of this file are derived from material licensed
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36 * @(#)vfs_lookup.c 8.4 (Berkeley) 2/16/94
39 #include <sys/cdefs.h>
40 __FBSDID("$FreeBSD$");
42 #include "opt_capsicum.h"
43 #include "opt_ktrace.h"
45 #include <sys/param.h>
46 #include <sys/systm.h>
47 #include <sys/kernel.h>
48 #include <sys/capsicum.h>
49 #include <sys/fcntl.h>
52 #include <sys/mutex.h>
53 #include <sys/namei.h>
54 #include <sys/vnode.h>
55 #include <sys/mount.h>
56 #include <sys/filedesc.h>
59 #include <sys/syscallsubr.h>
60 #include <sys/sysctl.h>
62 #include <sys/ktrace.h>
65 #include <security/audit/audit.h>
66 #include <security/mac/mac_framework.h>
70 #define NAMEI_DIAGNOSTIC 1
71 #undef NAMEI_DIAGNOSTIC
73 SDT_PROVIDER_DECLARE(vfs);
74 SDT_PROBE_DEFINE3(vfs, namei, lookup, entry, "struct vnode *", "char *",
76 SDT_PROBE_DEFINE2(vfs, namei, lookup, return, "int", "struct vnode *");
78 /* Allocation zone for namei. */
79 uma_zone_t namei_zone;
81 /* Placeholder vnode for mp traversal. */
82 static struct vnode *vp_crossmp;
85 crossmp_vop_islocked(struct vop_islocked_args *ap)
92 crossmp_vop_lock1(struct vop_lock1_args *ap)
95 struct lock *lk __unused;
96 const char *file __unused;
97 int flags, line __unused;
105 if ((flags & LK_SHARED) == 0)
106 panic("invalid lock request for crossmp");
108 WITNESS_CHECKORDER(&lk->lock_object, LOP_NEWORDER, file, line,
109 flags & LK_INTERLOCK ? &VI_MTX(vp)->lock_object : NULL);
110 WITNESS_LOCK(&lk->lock_object, 0, file, line);
111 if ((flags & LK_INTERLOCK) != 0)
113 LOCK_LOG_LOCK("SLOCK", &lk->lock_object, 0, 0, ap->a_file, line);
118 crossmp_vop_unlock(struct vop_unlock_args *ap)
121 struct lock *lk __unused;
128 if ((flags & LK_INTERLOCK) != 0)
130 WITNESS_UNLOCK(&lk->lock_object, 0, LOCK_FILE, LOCK_LINE);
131 LOCK_LOG_LOCK("SUNLOCK", &lk->lock_object, 0, 0, LOCK_FILE,
136 static struct vop_vector crossmp_vnodeops = {
137 .vop_default = &default_vnodeops,
138 .vop_islocked = crossmp_vop_islocked,
139 .vop_lock1 = crossmp_vop_lock1,
140 .vop_unlock = crossmp_vop_unlock,
143 struct nameicap_tracker {
145 TAILQ_ENTRY(nameicap_tracker) nm_link;
148 /* Zone for cap mode tracker elements used for dotdot capability checks. */
149 static uma_zone_t nt_zone;
152 nameiinit(void *dummy __unused)
155 namei_zone = uma_zcreate("NAMEI", MAXPATHLEN, NULL, NULL, NULL, NULL,
157 nt_zone = uma_zcreate("rentr", sizeof(struct nameicap_tracker),
158 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0);
159 getnewvnode("crossmp", NULL, &crossmp_vnodeops, &vp_crossmp);
161 SYSINIT(vfs, SI_SUB_VFS, SI_ORDER_SECOND, nameiinit, NULL);
163 static int lookup_cap_dotdot = 1;
164 SYSCTL_INT(_vfs, OID_AUTO, lookup_cap_dotdot, CTLFLAG_RWTUN,
165 &lookup_cap_dotdot, 0,
166 "enables \"..\" components in path lookup in capability mode");
167 static int lookup_cap_dotdot_nonlocal = 1;
168 SYSCTL_INT(_vfs, OID_AUTO, lookup_cap_dotdot_nonlocal, CTLFLAG_RWTUN,
169 &lookup_cap_dotdot_nonlocal, 0,
170 "enables \"..\" components in path lookup in capability mode "
171 "on non-local mount");
174 nameicap_tracker_add(struct nameidata *ndp, struct vnode *dp)
176 struct nameicap_tracker *nt;
178 if ((ndp->ni_lcf & NI_LCF_CAP_DOTDOT) == 0 || dp->v_type != VDIR)
180 nt = uma_zalloc(nt_zone, M_WAITOK);
183 TAILQ_INSERT_TAIL(&ndp->ni_cap_tracker, nt, nm_link);
187 nameicap_cleanup(struct nameidata *ndp)
189 struct nameicap_tracker *nt, *nt1;
191 KASSERT(TAILQ_EMPTY(&ndp->ni_cap_tracker) ||
192 (ndp->ni_lcf & NI_LCF_CAP_DOTDOT) != 0, ("not strictrelative"));
193 TAILQ_FOREACH_SAFE(nt, &ndp->ni_cap_tracker, nm_link, nt1) {
194 TAILQ_REMOVE(&ndp->ni_cap_tracker, nt, nm_link);
196 uma_zfree(nt_zone, nt);
201 * For dotdot lookups in capability mode, only allow the component
202 * lookup to succeed if the resulting directory was already traversed
203 * during the operation. Also fail dotdot lookups for non-local
204 * filesystems, where external agents might assist local lookups to
205 * escape the compartment.
208 nameicap_check_dotdot(struct nameidata *ndp, struct vnode *dp)
210 struct nameicap_tracker *nt;
213 if ((ndp->ni_lcf & NI_LCF_CAP_DOTDOT) == 0 || dp == NULL ||
217 if (lookup_cap_dotdot_nonlocal == 0 && mp != NULL &&
218 (mp->mnt_flag & MNT_LOCAL) == 0)
219 return (ENOTCAPABLE);
220 TAILQ_FOREACH_REVERSE(nt, &ndp->ni_cap_tracker, nameicap_tracker_head,
225 return (ENOTCAPABLE);
229 namei_cleanup_cnp(struct componentname *cnp)
232 uma_zfree(namei_zone, cnp->cn_pnbuf);
234 cnp->cn_pnbuf = NULL;
235 cnp->cn_nameptr = NULL;
240 namei_handle_root(struct nameidata *ndp, struct vnode **dpp)
242 struct componentname *cnp;
245 if ((ndp->ni_lcf & NI_LCF_STRICTRELATIVE) != 0) {
247 if (KTRPOINT(curthread, KTR_CAPFAIL))
248 ktrcapfail(CAPFAIL_LOOKUP, NULL, NULL);
250 return (ENOTCAPABLE);
252 while (*(cnp->cn_nameptr) == '/') {
256 *dpp = ndp->ni_rootdir;
262 * Convert a pathname into a pointer to a locked vnode.
264 * The FOLLOW flag is set when symbolic links are to be followed
265 * when they occur at the end of the name translation process.
266 * Symbolic links are always followed for all other pathname
267 * components other than the last.
269 * The segflg defines whether the name is to be copied from user
270 * space or kernel space.
272 * Overall outline of namei:
275 * get starting directory
276 * while (!done && !error) {
277 * call lookup to search path.
278 * if symbolic link, massage name in buffer and continue
282 namei(struct nameidata *ndp)
284 struct filedesc *fdp; /* pointer to file descriptor state */
285 char *cp; /* pointer into pathname argument */
286 struct vnode *dp; /* the directory we are searching */
287 struct iovec aiov; /* uio for reading symbolic links */
288 struct componentname *cnp;
293 int error, linklen, startdir_used;
298 ndp->ni_cnd.cn_cred = ndp->ni_cnd.cn_thread->td_ucred;
299 KASSERT(cnp->cn_cred && p, ("namei: bad cred/proc"));
300 KASSERT((cnp->cn_nameiop & (~OPMASK)) == 0,
301 ("namei: nameiop contaminated with flags"));
302 KASSERT((cnp->cn_flags & OPMASK) == 0,
303 ("namei: flags contaminated with nameiops"));
304 MPASS(ndp->ni_startdir == NULL || ndp->ni_startdir->v_type == VDIR ||
305 ndp->ni_startdir->v_type == VBAD);
307 TAILQ_INIT(&ndp->ni_cap_tracker);
310 /* We will set this ourselves if we need it. */
311 cnp->cn_flags &= ~TRAILINGSLASH;
314 * Get a buffer for the name to be translated, and copy the
315 * name into the buffer.
317 if ((cnp->cn_flags & HASBUF) == 0)
318 cnp->cn_pnbuf = uma_zalloc(namei_zone, M_WAITOK);
319 if (ndp->ni_segflg == UIO_SYSSPACE)
320 error = copystr(ndp->ni_dirp, cnp->cn_pnbuf, MAXPATHLEN,
323 error = copyinstr(ndp->ni_dirp, cnp->cn_pnbuf, MAXPATHLEN,
327 * Don't allow empty pathnames.
329 if (error == 0 && *cnp->cn_pnbuf == '\0')
332 #ifdef CAPABILITY_MODE
334 * In capability mode, lookups must be restricted to happen in
335 * the subtree with the root specified by the file descriptor:
336 * - The root must be real file descriptor, not the pseudo-descriptor
338 * - The passed path must be relative and not absolute.
339 * - If lookup_cap_dotdot is disabled, path must not contain the
341 * - If lookup_cap_dotdot is enabled, we verify that all '..'
342 * components lookups result in the directories which were
343 * previously walked by us, which prevents an escape from
346 if (error == 0 && IN_CAPABILITY_MODE(td) &&
347 (cnp->cn_flags & NOCAPCHECK) == 0) {
348 ndp->ni_lcf |= NI_LCF_STRICTRELATIVE;
349 if (ndp->ni_dirfd == AT_FDCWD) {
351 if (KTRPOINT(td, KTR_CAPFAIL))
352 ktrcapfail(CAPFAIL_LOOKUP, NULL, NULL);
359 namei_cleanup_cnp(cnp);
365 if (KTRPOINT(td, KTR_NAMEI)) {
366 KASSERT(cnp->cn_thread == curthread,
367 ("namei not using curthread"));
368 ktrnamei(cnp->cn_pnbuf);
372 * Get starting point for the translation.
375 ndp->ni_rootdir = fdp->fd_rdir;
376 vrefact(ndp->ni_rootdir);
377 ndp->ni_topdir = fdp->fd_jdir;
380 * If we are auditing the kernel pathname, save the user pathname.
382 if (cnp->cn_flags & AUDITVNODE1)
383 AUDIT_ARG_UPATH1(td, ndp->ni_dirfd, cnp->cn_pnbuf);
384 if (cnp->cn_flags & AUDITVNODE2)
385 AUDIT_ARG_UPATH2(td, ndp->ni_dirfd, cnp->cn_pnbuf);
389 cnp->cn_nameptr = cnp->cn_pnbuf;
390 if (cnp->cn_pnbuf[0] == '/') {
391 ndp->ni_resflags |= NIRES_ABS;
392 error = namei_handle_root(ndp, &dp);
394 if (ndp->ni_startdir != NULL) {
395 dp = ndp->ni_startdir;
397 } else if (ndp->ni_dirfd == AT_FDCWD) {
401 rights = ndp->ni_rightsneeded;
402 cap_rights_set(&rights, CAP_LOOKUP);
404 if (cnp->cn_flags & AUDITVNODE1)
405 AUDIT_ARG_ATFD1(ndp->ni_dirfd);
406 if (cnp->cn_flags & AUDITVNODE2)
407 AUDIT_ARG_ATFD2(ndp->ni_dirfd);
408 error = fgetvp_rights(td, ndp->ni_dirfd,
409 &rights, &ndp->ni_filecaps, &dp);
414 * If file descriptor doesn't have all rights,
415 * all lookups relative to it must also be
419 if (!cap_rights_contains(&ndp->ni_filecaps.fc_rights,
421 ndp->ni_filecaps.fc_fcntls != CAP_FCNTL_ALL ||
422 ndp->ni_filecaps.fc_nioctls != -1) {
423 ndp->ni_lcf |= NI_LCF_STRICTRELATIVE;
427 if (error == 0 && dp->v_type != VDIR)
430 FILEDESC_SUNLOCK(fdp);
431 if (ndp->ni_startdir != NULL && !startdir_used)
432 vrele(ndp->ni_startdir);
438 if ((ndp->ni_lcf & NI_LCF_STRICTRELATIVE) != 0 &&
439 lookup_cap_dotdot != 0)
440 ndp->ni_lcf |= NI_LCF_CAP_DOTDOT;
441 SDT_PROBE3(vfs, namei, lookup, entry, dp, cnp->cn_pnbuf,
444 ndp->ni_startdir = dp;
449 * If not a symbolic link, we're done.
451 if ((cnp->cn_flags & ISSYMLINK) == 0) {
452 vrele(ndp->ni_rootdir);
453 if ((cnp->cn_flags & (SAVENAME | SAVESTART)) == 0) {
454 namei_cleanup_cnp(cnp);
456 cnp->cn_flags |= HASBUF;
457 nameicap_cleanup(ndp);
458 SDT_PROBE2(vfs, namei, lookup, return, 0, ndp->ni_vp);
461 if (ndp->ni_loopcnt++ >= MAXSYMLINKS) {
466 if ((cnp->cn_flags & NOMACCHECK) == 0) {
467 error = mac_vnode_check_readlink(td->td_ucred,
473 if (ndp->ni_pathlen > 1)
474 cp = uma_zalloc(namei_zone, M_WAITOK);
478 aiov.iov_len = MAXPATHLEN;
479 auio.uio_iov = &aiov;
482 auio.uio_rw = UIO_READ;
483 auio.uio_segflg = UIO_SYSSPACE;
485 auio.uio_resid = MAXPATHLEN;
486 error = VOP_READLINK(ndp->ni_vp, &auio, cnp->cn_cred);
488 if (ndp->ni_pathlen > 1)
489 uma_zfree(namei_zone, cp);
492 linklen = MAXPATHLEN - auio.uio_resid;
494 if (ndp->ni_pathlen > 1)
495 uma_zfree(namei_zone, cp);
499 if (linklen + ndp->ni_pathlen > MAXPATHLEN) {
500 if (ndp->ni_pathlen > 1)
501 uma_zfree(namei_zone, cp);
502 error = ENAMETOOLONG;
505 if (ndp->ni_pathlen > 1) {
506 bcopy(ndp->ni_next, cp + linklen, ndp->ni_pathlen);
507 uma_zfree(namei_zone, cnp->cn_pnbuf);
510 cnp->cn_pnbuf[linklen] = '\0';
511 ndp->ni_pathlen += linklen;
515 * Check if root directory should replace current directory.
517 cnp->cn_nameptr = cnp->cn_pnbuf;
518 if (*(cnp->cn_nameptr) == '/') {
520 error = namei_handle_root(ndp, &dp);
529 vrele(ndp->ni_rootdir);
530 namei_cleanup_cnp(cnp);
531 nameicap_cleanup(ndp);
532 SDT_PROBE2(vfs, namei, lookup, return, error, NULL);
537 compute_cn_lkflags(struct mount *mp, int lkflags, int cnflags)
540 if (mp == NULL || ((lkflags & LK_SHARED) &&
541 (!(mp->mnt_kern_flag & MNTK_LOOKUP_SHARED) ||
542 ((cnflags & ISDOTDOT) &&
543 (mp->mnt_kern_flag & MNTK_LOOKUP_EXCL_DOTDOT))))) {
544 lkflags &= ~LK_SHARED;
545 lkflags |= LK_EXCLUSIVE;
547 lkflags |= LK_NODDLKTREAT;
552 needs_exclusive_leaf(struct mount *mp, int flags)
556 * Intermediate nodes can use shared locks, we only need to
557 * force an exclusive lock for leaf nodes.
559 if ((flags & (ISLASTCN | LOCKLEAF)) != (ISLASTCN | LOCKLEAF))
562 /* Always use exclusive locks if LOCKSHARED isn't set. */
563 if (!(flags & LOCKSHARED))
567 * For lookups during open(), if the mount point supports
568 * extended shared operations, then use a shared lock for the
569 * leaf node, otherwise use an exclusive lock.
571 if ((flags & ISOPEN) != 0)
572 return (!MNT_EXTENDED_SHARED(mp));
575 * Lookup requests outside of open() that specify LOCKSHARED
576 * only need a shared lock on the leaf vnode.
583 * This is a very central and rather complicated routine.
585 * The pathname is pointed to by ni_ptr and is of length ni_pathlen.
586 * The starting directory is taken from ni_startdir. The pathname is
587 * descended until done, or a symbolic link is encountered. The variable
588 * ni_more is clear if the path is completed; it is set to one if a
589 * symbolic link needing interpretation is encountered.
591 * The flag argument is LOOKUP, CREATE, RENAME, or DELETE depending on
592 * whether the name is to be looked up, created, renamed, or deleted.
593 * When CREATE, RENAME, or DELETE is specified, information usable in
594 * creating, renaming, or deleting a directory entry may be calculated.
595 * If flag has LOCKPARENT or'ed into it, the parent directory is returned
596 * locked. If flag has WANTPARENT or'ed into it, the parent directory is
597 * returned unlocked. Otherwise the parent directory is not returned. If
598 * the target of the pathname exists and LOCKLEAF is or'ed into the flag
599 * the target is returned locked, otherwise it is returned unlocked.
600 * When creating or renaming and LOCKPARENT is specified, the target may not
601 * be ".". When deleting and LOCKPARENT is specified, the target may be ".".
603 * Overall outline of lookup:
606 * identify next component of name at ndp->ni_ptr
607 * handle degenerate case where name is null string
608 * if .. and crossing mount points and on mounted filesys, find parent
609 * call VOP_LOOKUP routine for next component name
610 * directory vnode returned in ni_dvp, unlocked unless LOCKPARENT set
611 * component vnode returned in ni_vp (if it exists), locked.
612 * if result vnode is mounted on and crossing mount points,
613 * find mounted on vnode
614 * if more components of name, do next level at dirloop
615 * return the answer in ni_vp, locked if LOCKLEAF set
616 * if LOCKPARENT set, return locked parent in ni_dvp
617 * if WANTPARENT set, return unlocked parent in ni_dvp
620 lookup(struct nameidata *ndp)
622 char *cp; /* pointer into pathname argument */
623 char *prev_ni_next; /* saved ndp->ni_next */
624 struct vnode *dp = NULL; /* the directory we are searching */
625 struct vnode *tdp; /* saved dp */
626 struct mount *mp; /* mount table entry */
628 size_t prev_ni_pathlen; /* saved ndp->ni_pathlen */
629 int docache; /* == 0 do not cache last component */
630 int wantparent; /* 1 => wantparent or lockparent flag */
631 int rdonly; /* lookup read-only flag bit */
633 int dpunlocked = 0; /* dp has already been unlocked */
634 int relookup = 0; /* do not consume the path component */
635 struct componentname *cnp = &ndp->ni_cnd;
640 * Setup: break out flag bits into variables.
643 wantparent = cnp->cn_flags & (LOCKPARENT | WANTPARENT);
644 KASSERT(cnp->cn_nameiop == LOOKUP || wantparent,
645 ("CREATE, DELETE, RENAME require LOCKPARENT or WANTPARENT."));
646 docache = (cnp->cn_flags & NOCACHE) ^ NOCACHE;
647 if (cnp->cn_nameiop == DELETE ||
648 (wantparent && cnp->cn_nameiop != CREATE &&
649 cnp->cn_nameiop != LOOKUP))
651 rdonly = cnp->cn_flags & RDONLY;
652 cnp->cn_flags &= ~ISSYMLINK;
655 * We use shared locks until we hit the parent of the last cn then
656 * we adjust based on the requesting flags.
658 cnp->cn_lkflags = LK_SHARED;
659 dp = ndp->ni_startdir;
660 ndp->ni_startdir = NULLVP;
662 compute_cn_lkflags(dp->v_mount, cnp->cn_lkflags | LK_RETRY,
667 * Search a new directory.
669 * The last component of the filename is left accessible via
670 * cnp->cn_nameptr for callers that need the name. Callers needing
671 * the name set the SAVENAME flag. When done, they assume
672 * responsibility for freeing the pathname buffer.
674 for (cp = cnp->cn_nameptr; *cp != 0 && *cp != '/'; cp++)
676 cnp->cn_namelen = cp - cnp->cn_nameptr;
677 if (cnp->cn_namelen > NAME_MAX) {
678 error = ENAMETOOLONG;
681 #ifdef NAMEI_DIAGNOSTIC
684 printf("{%s}: ", cnp->cn_nameptr);
687 prev_ni_pathlen = ndp->ni_pathlen;
688 ndp->ni_pathlen -= cnp->cn_namelen;
689 KASSERT(ndp->ni_pathlen <= PATH_MAX,
690 ("%s: ni_pathlen underflow to %zd\n", __func__, ndp->ni_pathlen));
691 prev_ni_next = ndp->ni_next;
695 * Replace multiple slashes by a single slash and trailing slashes
696 * by a null. This must be done before VOP_LOOKUP() because some
697 * fs's don't know about trailing slashes. Remember if there were
698 * trailing slashes to handle symlinks, existing non-directories
699 * and non-existing files that won't be directories specially later.
701 while (*cp == '/' && (cp[1] == '/' || cp[1] == '\0')) {
705 *ndp->ni_next = '\0';
706 cnp->cn_flags |= TRAILINGSLASH;
711 cnp->cn_flags |= MAKEENTRY;
712 if (*cp == '\0' && docache == 0)
713 cnp->cn_flags &= ~MAKEENTRY;
714 if (cnp->cn_namelen == 2 &&
715 cnp->cn_nameptr[1] == '.' && cnp->cn_nameptr[0] == '.')
716 cnp->cn_flags |= ISDOTDOT;
718 cnp->cn_flags &= ~ISDOTDOT;
719 if (*ndp->ni_next == 0)
720 cnp->cn_flags |= ISLASTCN;
722 cnp->cn_flags &= ~ISLASTCN;
724 if ((cnp->cn_flags & ISLASTCN) != 0 &&
725 cnp->cn_namelen == 1 && cnp->cn_nameptr[0] == '.' &&
726 (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME)) {
731 nameicap_tracker_add(ndp, dp);
734 * Check for degenerate name (e.g. / or "")
735 * which is a way of talking about a directory,
736 * e.g. like "/." or ".".
738 if (cnp->cn_nameptr[0] == '\0') {
739 if (dp->v_type != VDIR) {
743 if (cnp->cn_nameiop != LOOKUP) {
753 if (cnp->cn_flags & AUDITVNODE1)
754 AUDIT_ARG_VNODE1(dp);
755 else if (cnp->cn_flags & AUDITVNODE2)
756 AUDIT_ARG_VNODE2(dp);
758 if (!(cnp->cn_flags & (LOCKPARENT | LOCKLEAF)))
760 /* XXX This should probably move to the top of function. */
761 if (cnp->cn_flags & SAVESTART)
762 panic("lookup: SAVESTART");
767 * Handle "..": five special cases.
768 * 0. If doing a capability lookup and lookup_cap_dotdot is
769 * disabled, return ENOTCAPABLE.
770 * 1. Return an error if this is the last component of
771 * the name and the operation is DELETE or RENAME.
772 * 2. If at root directory (e.g. after chroot)
773 * or at absolute root directory
774 * then ignore it so can't get out.
775 * 3. If this vnode is the root of a mounted
776 * filesystem, then replace it with the
777 * vnode which was mounted on so we take the
778 * .. in the other filesystem.
779 * 4. If the vnode is the top directory of
780 * the jail or chroot, don't let them out.
781 * 5. If doing a capability lookup and lookup_cap_dotdot is
782 * enabled, return ENOTCAPABLE if the lookup would escape
783 * from the initial file descriptor directory. Checks are
784 * done by ensuring that namei() already traversed the
785 * result of dotdot lookup.
787 if (cnp->cn_flags & ISDOTDOT) {
788 if ((ndp->ni_lcf & (NI_LCF_STRICTRELATIVE | NI_LCF_CAP_DOTDOT))
789 == NI_LCF_STRICTRELATIVE) {
791 if (KTRPOINT(curthread, KTR_CAPFAIL))
792 ktrcapfail(CAPFAIL_LOOKUP, NULL, NULL);
797 if ((cnp->cn_flags & ISLASTCN) != 0 &&
798 (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME)) {
803 for (pr = cnp->cn_cred->cr_prison; pr != NULL;
805 if (dp == pr->pr_root)
807 if (dp == ndp->ni_rootdir ||
808 dp == ndp->ni_topdir ||
811 ((dp->v_vflag & VV_ROOT) != 0 &&
812 (cnp->cn_flags & NOCROSSMOUNT) != 0)) {
818 if ((dp->v_vflag & VV_ROOT) == 0)
820 if (dp->v_iflag & VI_DOOMED) { /* forced unmount */
825 dp = dp->v_mount->mnt_vnodecovered;
829 compute_cn_lkflags(dp->v_mount, cnp->cn_lkflags |
830 LK_RETRY, ISDOTDOT));
831 error = nameicap_check_dotdot(ndp, dp);
834 if (KTRPOINT(curthread, KTR_CAPFAIL))
835 ktrcapfail(CAPFAIL_LOOKUP, NULL, NULL);
843 * We now have a segment name to search for, and a directory to search.
847 if ((cnp->cn_flags & NOMACCHECK) == 0) {
848 error = mac_vnode_check_lookup(cnp->cn_thread->td_ucred, dp,
856 ASSERT_VOP_LOCKED(dp, "lookup");
858 * If we have a shared lock we may need to upgrade the lock for the
861 if ((cnp->cn_flags & LOCKPARENT) && (cnp->cn_flags & ISLASTCN) &&
862 dp != vp_crossmp && VOP_ISLOCKED(dp) == LK_SHARED)
863 vn_lock(dp, LK_UPGRADE|LK_RETRY);
864 if ((dp->v_iflag & VI_DOOMED) != 0) {
869 * If we're looking up the last component and we need an exclusive
870 * lock, adjust our lkflags.
872 if (needs_exclusive_leaf(dp->v_mount, cnp->cn_flags))
873 cnp->cn_lkflags = LK_EXCLUSIVE;
874 #ifdef NAMEI_DIAGNOSTIC
875 vn_printf(dp, "lookup in ");
877 lkflags_save = cnp->cn_lkflags;
878 cnp->cn_lkflags = compute_cn_lkflags(dp->v_mount, cnp->cn_lkflags,
880 error = VOP_LOOKUP(dp, &ndp->ni_vp, cnp);
881 cnp->cn_lkflags = lkflags_save;
883 KASSERT(ndp->ni_vp == NULL, ("leaf should be empty"));
884 #ifdef NAMEI_DIAGNOSTIC
885 printf("not found\n");
887 if ((error == ENOENT) &&
888 (dp->v_vflag & VV_ROOT) && (dp->v_mount != NULL) &&
889 (dp->v_mount->mnt_flag & MNT_UNION)) {
891 dp = dp->v_mount->mnt_vnodecovered;
895 compute_cn_lkflags(dp->v_mount, cnp->cn_lkflags |
896 LK_RETRY, cnp->cn_flags));
897 nameicap_tracker_add(ndp, dp);
901 if (error == ERELOOKUP) {
909 if (error != EJUSTRETURN)
912 * At this point, we know we're at the end of the
913 * pathname. If creating / renaming, we can consider
914 * allowing the file or directory to be created / renamed,
915 * provided we're not on a read-only filesystem.
921 /* trailing slash only allowed for directories */
922 if ((cnp->cn_flags & TRAILINGSLASH) &&
923 !(cnp->cn_flags & WILLBEDIR)) {
927 if ((cnp->cn_flags & LOCKPARENT) == 0)
930 * We return with ni_vp NULL to indicate that the entry
931 * doesn't currently exist, leaving a pointer to the
932 * (possibly locked) directory vnode in ndp->ni_dvp.
934 if (cnp->cn_flags & SAVESTART) {
935 ndp->ni_startdir = ndp->ni_dvp;
936 VREF(ndp->ni_startdir);
942 #ifdef NAMEI_DIAGNOSTIC
948 * Check to see if the vnode has been mounted on;
949 * if so find the root of the mounted filesystem.
951 while (dp->v_type == VDIR && (mp = dp->v_mountedhere) &&
952 (cnp->cn_flags & NOCROSSMOUNT) == 0) {
956 if (dp != ndp->ni_dvp)
961 ndp->ni_dvp = vp_crossmp;
962 error = VFS_ROOT(mp, compute_cn_lkflags(mp, cnp->cn_lkflags,
963 cnp->cn_flags), &tdp);
965 if (vn_lock(vp_crossmp, LK_SHARED | LK_NOWAIT))
966 panic("vp_crossmp exclusively locked or reclaimed");
971 ndp->ni_vp = dp = tdp;
975 * Check for symbolic link
977 if ((dp->v_type == VLNK) &&
978 ((cnp->cn_flags & FOLLOW) || (cnp->cn_flags & TRAILINGSLASH) ||
979 *ndp->ni_next == '/')) {
980 cnp->cn_flags |= ISSYMLINK;
981 if (dp->v_iflag & VI_DOOMED) {
983 * We can't know whether the directory was mounted with
984 * NOSYMFOLLOW, so we can't follow safely.
989 if (dp->v_mount->mnt_flag & MNT_NOSYMFOLLOW) {
994 * Symlink code always expects an unlocked dvp.
996 if (ndp->ni_dvp != ndp->ni_vp) {
997 VOP_UNLOCK(ndp->ni_dvp, 0);
1005 * Not a symbolic link that we will follow. Continue with the
1006 * next component if there is any; otherwise, we're done.
1008 KASSERT((cnp->cn_flags & ISLASTCN) || *ndp->ni_next == '/',
1009 ("lookup: invalid path state."));
1012 ndp->ni_pathlen = prev_ni_pathlen;
1013 ndp->ni_next = prev_ni_next;
1014 if (ndp->ni_dvp != dp)
1020 if (cnp->cn_flags & ISDOTDOT) {
1021 error = nameicap_check_dotdot(ndp, ndp->ni_vp);
1024 if (KTRPOINT(curthread, KTR_CAPFAIL))
1025 ktrcapfail(CAPFAIL_LOOKUP, NULL, NULL);
1030 if (*ndp->ni_next == '/') {
1031 cnp->cn_nameptr = ndp->ni_next;
1032 while (*cnp->cn_nameptr == '/') {
1036 if (ndp->ni_dvp != dp)
1043 * If we're processing a path with a trailing slash,
1044 * check that the end result is a directory.
1046 if ((cnp->cn_flags & TRAILINGSLASH) && dp->v_type != VDIR) {
1051 * Disallow directory write attempts on read-only filesystems.
1054 (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME)) {
1058 if (cnp->cn_flags & SAVESTART) {
1059 ndp->ni_startdir = ndp->ni_dvp;
1060 VREF(ndp->ni_startdir);
1063 ni_dvp_unlocked = 2;
1064 if (ndp->ni_dvp != dp)
1068 } else if ((cnp->cn_flags & LOCKPARENT) == 0 && ndp->ni_dvp != dp) {
1069 VOP_UNLOCK(ndp->ni_dvp, 0);
1070 ni_dvp_unlocked = 1;
1073 if (cnp->cn_flags & AUDITVNODE1)
1074 AUDIT_ARG_VNODE1(dp);
1075 else if (cnp->cn_flags & AUDITVNODE2)
1076 AUDIT_ARG_VNODE2(dp);
1078 if ((cnp->cn_flags & LOCKLEAF) == 0)
1082 * Because of shared lookup we may have the vnode shared locked, but
1083 * the caller may want it to be exclusively locked.
1085 if (needs_exclusive_leaf(dp->v_mount, cnp->cn_flags) &&
1086 VOP_ISLOCKED(dp) != LK_EXCLUSIVE) {
1087 vn_lock(dp, LK_UPGRADE | LK_RETRY);
1088 if (dp->v_iflag & VI_DOOMED) {
1096 if (ni_dvp_unlocked != 2) {
1097 if (dp != ndp->ni_dvp && !ni_dvp_unlocked)
1110 * relookup - lookup a path name component
1111 * Used by lookup to re-acquire things.
1114 relookup(struct vnode *dvp, struct vnode **vpp, struct componentname *cnp)
1116 struct vnode *dp = NULL; /* the directory we are searching */
1117 int wantparent; /* 1 => wantparent or lockparent flag */
1118 int rdonly; /* lookup read-only flag bit */
1121 KASSERT(cnp->cn_flags & ISLASTCN,
1122 ("relookup: Not given last component."));
1124 * Setup: break out flag bits into variables.
1126 wantparent = cnp->cn_flags & (LOCKPARENT|WANTPARENT);
1127 KASSERT(wantparent, ("relookup: parent not wanted."));
1128 rdonly = cnp->cn_flags & RDONLY;
1129 cnp->cn_flags &= ~ISSYMLINK;
1131 cnp->cn_lkflags = LK_EXCLUSIVE;
1132 vn_lock(dp, LK_EXCLUSIVE | LK_RETRY);
1135 * Search a new directory.
1137 * The last component of the filename is left accessible via
1138 * cnp->cn_nameptr for callers that need the name. Callers needing
1139 * the name set the SAVENAME flag. When done, they assume
1140 * responsibility for freeing the pathname buffer.
1142 #ifdef NAMEI_DIAGNOSTIC
1143 printf("{%s}: ", cnp->cn_nameptr);
1147 * Check for "" which represents the root directory after slash
1150 if (cnp->cn_nameptr[0] == '\0') {
1152 * Support only LOOKUP for "/" because lookup()
1153 * can't succeed for CREATE, DELETE and RENAME.
1155 KASSERT(cnp->cn_nameiop == LOOKUP, ("nameiop must be LOOKUP"));
1156 KASSERT(dp->v_type == VDIR, ("dp is not a directory"));
1158 if (!(cnp->cn_flags & LOCKLEAF))
1161 /* XXX This should probably move to the top of function. */
1162 if (cnp->cn_flags & SAVESTART)
1163 panic("lookup: SAVESTART");
1167 if (cnp->cn_flags & ISDOTDOT)
1168 panic ("relookup: lookup on dot-dot");
1171 * We now have a segment name to search for, and a directory to search.
1173 #ifdef NAMEI_DIAGNOSTIC
1174 vn_printf(dp, "search in ");
1176 if ((error = VOP_LOOKUP(dp, vpp, cnp)) != 0) {
1177 KASSERT(*vpp == NULL, ("leaf should be empty"));
1178 if (error != EJUSTRETURN)
1181 * If creating and at end of pathname, then can consider
1182 * allowing file to be created.
1188 /* ASSERT(dvp == ndp->ni_startdir) */
1189 if (cnp->cn_flags & SAVESTART)
1191 if ((cnp->cn_flags & LOCKPARENT) == 0)
1194 * We return with ni_vp NULL to indicate that the entry
1195 * doesn't currently exist, leaving a pointer to the
1196 * (possibly locked) directory vnode in ndp->ni_dvp.
1204 * Disallow directory write attempts on read-only filesystems.
1207 (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME)) {
1216 * Set the parent lock/ref state to the requested state.
1218 if ((cnp->cn_flags & LOCKPARENT) == 0 && dvp != dp) {
1223 } else if (!wantparent)
1226 * Check for symbolic link
1228 KASSERT(dp->v_type != VLNK || !(cnp->cn_flags & FOLLOW),
1229 ("relookup: symlink found.\n"));
1231 /* ASSERT(dvp == ndp->ni_startdir) */
1232 if (cnp->cn_flags & SAVESTART)
1235 if ((cnp->cn_flags & LOCKLEAF) == 0)
1245 NDINIT_ALL(struct nameidata *ndp, u_long op, u_long flags, enum uio_seg segflg,
1246 const char *namep, int dirfd, struct vnode *startdir, cap_rights_t *rightsp,
1250 ndp->ni_cnd.cn_nameiop = op;
1251 ndp->ni_cnd.cn_flags = flags;
1252 ndp->ni_segflg = segflg;
1253 ndp->ni_dirp = namep;
1254 ndp->ni_dirfd = dirfd;
1255 ndp->ni_startdir = startdir;
1256 ndp->ni_resflags = 0;
1257 if (rightsp != NULL)
1258 ndp->ni_rightsneeded = *rightsp;
1260 cap_rights_init(&ndp->ni_rightsneeded);
1261 filecaps_init(&ndp->ni_filecaps);
1262 ndp->ni_cnd.cn_thread = td;
1266 * Free data allocated by namei(); see namei(9) for details.
1269 NDFREE(struct nameidata *ndp, const u_int flags)
1277 if (!(flags & NDF_NO_FREE_PNBUF) &&
1278 (ndp->ni_cnd.cn_flags & HASBUF)) {
1279 uma_zfree(namei_zone, ndp->ni_cnd.cn_pnbuf);
1280 ndp->ni_cnd.cn_flags &= ~HASBUF;
1282 if (!(flags & NDF_NO_VP_UNLOCK) &&
1283 (ndp->ni_cnd.cn_flags & LOCKLEAF) && ndp->ni_vp)
1285 if (!(flags & NDF_NO_DVP_UNLOCK) &&
1286 (ndp->ni_cnd.cn_flags & LOCKPARENT) &&
1287 ndp->ni_dvp != ndp->ni_vp)
1289 if (!(flags & NDF_NO_VP_RELE) && ndp->ni_vp) {
1298 VOP_UNLOCK(ndp->ni_vp, 0);
1299 if (!(flags & NDF_NO_DVP_RELE) &&
1300 (ndp->ni_cnd.cn_flags & (LOCKPARENT|WANTPARENT))) {
1309 VOP_UNLOCK(ndp->ni_dvp, 0);
1310 if (!(flags & NDF_NO_STARTDIR_RELE) &&
1311 (ndp->ni_cnd.cn_flags & SAVESTART)) {
1312 vrele(ndp->ni_startdir);
1313 ndp->ni_startdir = NULL;
1318 * Determine if there is a suitable alternate filename under the specified
1319 * prefix for the specified path. If the create flag is set, then the
1320 * alternate prefix will be used so long as the parent directory exists.
1321 * This is used by the various compatibility ABIs so that Linux binaries prefer
1322 * files under /compat/linux for example. The chosen path (whether under
1323 * the prefix or under /) is returned in a kernel malloc'd buffer pointed
1324 * to by pathbuf. The caller is responsible for free'ing the buffer from
1325 * the M_TEMP bucket if one is returned.
1328 kern_alternate_path(struct thread *td, const char *prefix, const char *path,
1329 enum uio_seg pathseg, char **pathbuf, int create, int dirfd)
1331 struct nameidata nd, ndroot;
1332 char *ptr, *buf, *cp;
1336 buf = (char *) malloc(MAXPATHLEN, M_TEMP, M_WAITOK);
1339 /* Copy the prefix into the new pathname as a starting point. */
1340 len = strlcpy(buf, prefix, MAXPATHLEN);
1341 if (len >= MAXPATHLEN) {
1346 sz = MAXPATHLEN - len;
1349 /* Append the filename to the prefix. */
1350 if (pathseg == UIO_SYSSPACE)
1351 error = copystr(path, ptr, sz, &len);
1353 error = copyinstr(path, ptr, sz, &len);
1361 /* Only use a prefix with absolute pathnames. */
1367 if (dirfd != AT_FDCWD) {
1369 * We want the original because the "prefix" is
1370 * included in the already opened dirfd.
1372 bcopy(ptr, buf, len);
1377 * We know that there is a / somewhere in this pathname.
1378 * Search backwards for it, to find the file's parent dir
1379 * to see if it exists in the alternate tree. If it does,
1380 * and we want to create a file (cflag is set). We don't
1381 * need to worry about the root comparison in this case.
1385 for (cp = &ptr[len] - 1; *cp != '/'; cp--);
1388 NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_SYSSPACE, buf, td);
1394 NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_SYSSPACE, buf, td);
1401 * We now compare the vnode of the prefix to the one
1402 * vnode asked. If they resolve to be the same, then we
1403 * ignore the match so that the real root gets used.
1404 * This avoids the problem of traversing "../.." to find the
1405 * root directory and never finding it, because "/" resolves
1406 * to the emulation root directory. This is expensive :-(
1408 NDINIT(&ndroot, LOOKUP, FOLLOW, UIO_SYSSPACE, prefix,
1411 /* We shouldn't ever get an error from this namei(). */
1412 error = namei(&ndroot);
1414 if (nd.ni_vp == ndroot.ni_vp)
1417 NDFREE(&ndroot, NDF_ONLY_PNBUF);
1418 vrele(ndroot.ni_vp);
1422 NDFREE(&nd, NDF_ONLY_PNBUF);
1426 /* If there was an error, use the original path name. */
1428 bcopy(ptr, buf, len);