2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
4 * Copyright (c) 2014 The FreeBSD Foundation
6 * This software was developed by Edward Tomasz Napierala under sponsorship
7 * from the FreeBSD Foundation.
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 #include <sys/cdefs.h>
33 __FBSDID("$FreeBSD$");
35 #include <sys/param.h>
36 #include <sys/systm.h>
37 #include <sys/kernel.h>
38 #include <sys/condvar.h>
39 #include <sys/dirent.h>
40 #include <sys/fcntl.h>
42 #include <sys/mount.h>
43 #include <sys/mutex.h>
44 #include <sys/namei.h>
45 #include <sys/signalvar.h>
47 #include <sys/taskqueue.h>
49 #include <sys/vnode.h>
50 #include <machine/atomic.h>
53 #include <fs/autofs/autofs.h>
55 static int autofs_trigger_vn(struct vnode *vp, const char *path,
56 int pathlen, struct vnode **newvp);
58 extern struct autofs_softc *autofs_softc;
61 autofs_access(struct vop_access_args *ap)
65 * Nothing to do here; the only kind of access control
66 * needed is in autofs_mkdir().
73 autofs_getattr(struct vop_getattr_args *ap)
75 struct vnode *vp, *newvp;
76 struct autofs_node *anp;
86 KASSERT(ap->a_vp->v_type == VDIR, ("!VDIR"));
89 * The reason we must do this is that some tree-walking software,
90 * namely fts(3), assumes that stat(".") results will not change
91 * between chdir("subdir") and chdir(".."), and fails with ENOENT
94 if (autofs_mount_on_stat && autofs_cached(anp, NULL, 0) == false &&
95 autofs_ignore_thread(curthread) == false) {
96 error = autofs_trigger_vn(vp, "", 0, &newvp);
101 error = VOP_GETATTR(newvp, ap->a_vap,
110 vap->va_nlink = 3; /* XXX */
113 vap->va_rdev = NODEV;
114 vap->va_fsid = mp->mnt_stat.f_fsid.val[0];
115 vap->va_fileid = anp->an_fileno;
116 vap->va_size = S_BLKSIZE;
117 vap->va_blocksize = S_BLKSIZE;
118 vap->va_mtime = anp->an_ctime;
119 vap->va_atime = anp->an_ctime;
120 vap->va_ctime = anp->an_ctime;
121 vap->va_birthtime = anp->an_ctime;
125 vap->va_bytes = S_BLKSIZE;
133 * Unlock the vnode, request automountd(8) action, and then lock it back.
134 * If anything got mounted on top of the vnode, return the new filesystem's
135 * root vnode in 'newvp', locked.
138 autofs_trigger_vn(struct vnode *vp, const char *path, int pathlen,
139 struct vnode **newvp)
141 struct autofs_node *anp;
142 int error, lock_flags;
147 * Release the vnode lock, so that other operations, in partcular
148 * mounting a filesystem on top of it, can proceed. Increase use
149 * count, to prevent the vnode from being deallocated and to prevent
150 * filesystem from being unmounted.
152 lock_flags = VOP_ISLOCKED(vp);
156 sx_xlock(&autofs_softc->sc_lock);
159 * XXX: Workaround for mounting the same thing multiple times; revisit.
161 if (vp->v_mountedhere != NULL) {
166 error = autofs_trigger(anp, path, pathlen);
168 sx_xunlock(&autofs_softc->sc_lock);
169 vn_lock(vp, lock_flags | LK_RETRY);
171 if (VN_IS_DOOMED(vp)) {
172 AUTOFS_DEBUG("VIRF_DOOMED");
179 if (vp->v_mountedhere == NULL) {
184 * If the operation that succeeded was mount, then mark
185 * the node as non-cached. Otherwise, if someone unmounts
186 * the filesystem before the cache times out, we will fail
189 anp->an_cached = false;
192 error = VFS_ROOT(vp->v_mountedhere, lock_flags, newvp);
194 AUTOFS_WARN("VFS_ROOT() failed with error %d", error);
202 autofs_vget_callback(struct mount *mp, void *arg, int flags,
206 return (autofs_node_vn(arg, mp, flags, vpp));
210 autofs_lookup(struct vop_lookup_args *ap)
212 struct vnode *dvp, *newvp, **vpp;
214 struct autofs_mount *amp;
215 struct autofs_node *anp, *child;
216 struct componentname *cnp;
222 amp = VFSTOAUTOFS(mp);
226 if (cnp->cn_flags & ISDOTDOT) {
227 KASSERT(anp->an_parent != NULL, ("NULL parent"));
229 * Note that in this case, dvp is the child vnode, and we
230 * are looking up the parent vnode - exactly reverse from
231 * normal operation. Unlocking dvp requires some rather
232 * tricky unlock/relock dance to prevent mp from being freed;
233 * use vn_vget_ino_gen() which takes care of all that.
235 error = vn_vget_ino_gen(dvp, autofs_vget_callback,
236 anp->an_parent, cnp->cn_lkflags, vpp);
238 AUTOFS_WARN("vn_vget_ino_gen() failed with error %d",
245 if (cnp->cn_namelen == 1 && cnp->cn_nameptr[0] == '.') {
252 if (autofs_cached(anp, cnp->cn_nameptr, cnp->cn_namelen) == false &&
253 autofs_ignore_thread(cnp->cn_thread) == false) {
254 error = autofs_trigger_vn(dvp,
255 cnp->cn_nameptr, cnp->cn_namelen, &newvp);
261 * The target filesystem got automounted.
262 * Let the lookup(9) go around with the same
271 error = autofs_node_find(anp, cnp->cn_nameptr, cnp->cn_namelen, &child);
273 if ((cnp->cn_flags & ISLASTCN) && cnp->cn_nameiop == CREATE) {
275 return (EJUSTRETURN);
283 * XXX: Dropping the node here is ok, because we never remove nodes.
287 error = autofs_node_vn(child, mp, cnp->cn_lkflags, vpp);
289 if ((cnp->cn_flags & ISLASTCN) && cnp->cn_nameiop == CREATE)
290 return (EJUSTRETURN);
299 autofs_mkdir(struct vop_mkdir_args *ap)
302 struct autofs_node *anp;
303 struct autofs_mount *amp;
304 struct autofs_node *child;
309 amp = VFSTOAUTOFS(vp->v_mount);
312 * Do not allow mkdir() if the calling thread is not
313 * automountd(8) descendant.
315 if (autofs_ignore_thread(curthread) == false)
319 error = autofs_node_new(anp, amp, ap->a_cnp->cn_nameptr,
320 ap->a_cnp->cn_namelen, &child);
327 error = autofs_node_vn(child, vp->v_mount, LK_EXCLUSIVE, ap->a_vpp);
333 autofs_print(struct vop_print_args *ap)
336 struct autofs_node *anp;
341 printf(" name \"%s\", fileno %d, cached %d, wildcards %d\n",
342 anp->an_name, anp->an_fileno, anp->an_cached, anp->an_wildcards);
348 * Write out a single 'struct dirent', based on 'name' and 'fileno' arguments.
351 autofs_readdir_one(struct uio *uio, const char *name, int fileno,
354 struct dirent dirent;
355 size_t namlen, reclen;
358 namlen = strlen(name);
359 reclen = _GENERIC_DIRLEN(namlen);
366 if (uio->uio_resid < reclen)
369 dirent.d_fileno = fileno;
370 dirent.d_reclen = reclen;
371 dirent.d_type = DT_DIR;
372 dirent.d_namlen = namlen;
373 memcpy(dirent.d_name, name, namlen);
374 dirent_terminate(&dirent);
375 error = uiomove(&dirent, reclen, uio);
381 autofs_dirent_reclen(const char *name)
385 (void)autofs_readdir_one(NULL, name, -1, &reclen);
391 autofs_readdir(struct vop_readdir_args *ap)
393 struct vnode *vp, *newvp;
394 struct autofs_mount *amp;
395 struct autofs_node *anp, *child;
397 size_t reclen, reclens;
398 ssize_t initial_resid;
402 amp = VFSTOAUTOFS(vp->v_mount);
405 initial_resid = ap->a_uio->uio_resid;
407 KASSERT(vp->v_type == VDIR, ("!VDIR"));
409 if (autofs_cached(anp, NULL, 0) == false &&
410 autofs_ignore_thread(curthread) == false) {
411 error = autofs_trigger_vn(vp, "", 0, &newvp);
416 error = VOP_READDIR(newvp, ap->a_uio, ap->a_cred,
417 ap->a_eofflag, ap->a_ncookies, ap->a_cookies);
423 if (uio->uio_offset < 0)
426 if (ap->a_eofflag != NULL)
427 *ap->a_eofflag = FALSE;
430 * Write out the directory entry for ".". This is conditional
431 * on the current offset into the directory; same applies to the
432 * other two cases below.
434 if (uio->uio_offset == 0) {
435 error = autofs_readdir_one(uio, ".", anp->an_fileno, &reclen);
439 reclens = autofs_dirent_reclen(".");
442 * Write out the directory entry for "..".
444 if (uio->uio_offset <= reclens) {
445 if (uio->uio_offset != reclens)
447 if (anp->an_parent == NULL) {
448 error = autofs_readdir_one(uio, "..",
449 anp->an_fileno, &reclen);
451 error = autofs_readdir_one(uio, "..",
452 anp->an_parent->an_fileno, &reclen);
458 reclens += autofs_dirent_reclen("..");
461 * Write out the directory entries for subdirectories.
464 RB_FOREACH(child, autofs_node_tree, &anp->an_children) {
466 * Check the offset to skip entries returned by previous
467 * calls to getdents().
469 if (uio->uio_offset > reclens) {
470 reclens += autofs_dirent_reclen(child->an_name);
475 * Prevent seeking into the middle of dirent.
477 if (uio->uio_offset != reclens) {
482 error = autofs_readdir_one(uio, child->an_name,
483 child->an_fileno, &reclen);
492 if (ap->a_eofflag != NULL)
493 *ap->a_eofflag = TRUE;
499 * Return error if the initial buffer was too small to do anything.
501 if (uio->uio_resid == initial_resid)
505 * Don't return an error if we managed to copy out some entries.
507 if (uio->uio_resid < reclen)
514 autofs_reclaim(struct vop_reclaim_args *ap)
517 struct autofs_node *anp;
523 * We do not free autofs_node here; instead we are
524 * destroying them in autofs_node_delete().
526 sx_xlock(&anp->an_vnode_lock);
527 anp->an_vnode = NULL;
529 sx_xunlock(&anp->an_vnode_lock);
534 struct vop_vector autofs_vnodeops = {
535 .vop_default = &default_vnodeops,
537 .vop_access = autofs_access,
538 .vop_lookup = autofs_lookup,
539 .vop_create = VOP_EOPNOTSUPP,
540 .vop_getattr = autofs_getattr,
541 .vop_link = VOP_EOPNOTSUPP,
542 .vop_mkdir = autofs_mkdir,
543 .vop_mknod = VOP_EOPNOTSUPP,
544 .vop_print = autofs_print,
545 .vop_read = VOP_EOPNOTSUPP,
546 .vop_readdir = autofs_readdir,
547 .vop_remove = VOP_EOPNOTSUPP,
548 .vop_rename = VOP_EOPNOTSUPP,
549 .vop_rmdir = VOP_EOPNOTSUPP,
550 .vop_setattr = VOP_EOPNOTSUPP,
551 .vop_symlink = VOP_EOPNOTSUPP,
552 .vop_write = VOP_EOPNOTSUPP,
553 .vop_reclaim = autofs_reclaim,
555 VFS_VOP_VECTOR_REGISTER(autofs_vnodeops);
558 autofs_node_new(struct autofs_node *parent, struct autofs_mount *amp,
559 const char *name, int namelen, struct autofs_node **anpp)
561 struct autofs_node *anp;
563 if (parent != NULL) {
564 AUTOFS_ASSERT_XLOCKED(parent->an_mount);
566 KASSERT(autofs_node_find(parent, name, namelen, NULL) == ENOENT,
567 ("node \"%s\" already exists", name));
570 anp = uma_zalloc(autofs_node_zone, M_WAITOK | M_ZERO);
572 anp->an_name = strndup(name, namelen, M_AUTOFS);
574 anp->an_name = strdup(name, M_AUTOFS);
575 anp->an_fileno = atomic_fetchadd_int(&->am_last_fileno, 1);
576 callout_init(&anp->an_callout, 1);
578 * The reason for SX_NOWITNESS here is that witness(4)
579 * cannot tell vnodes apart, so the following perfectly
580 * valid lock order...
582 * vnode lock A -> autofsvlk B -> vnode lock B
584 * ... gets reported as a LOR.
586 sx_init_flags(&anp->an_vnode_lock, "autofsvlk", SX_NOWITNESS);
587 getnanotime(&anp->an_ctime);
588 anp->an_parent = parent;
591 RB_INSERT(autofs_node_tree, &parent->an_children, anp);
592 RB_INIT(&anp->an_children);
599 autofs_node_find(struct autofs_node *parent, const char *name,
600 int namelen, struct autofs_node **anpp)
602 struct autofs_node *anp, find;
605 AUTOFS_ASSERT_LOCKED(parent->an_mount);
608 find.an_name = strndup(name, namelen, M_AUTOFS);
610 find.an_name = strdup(name, M_AUTOFS);
612 anp = RB_FIND(autofs_node_tree, &parent->an_children, &find);
621 free(find.an_name, M_AUTOFS);
627 autofs_node_delete(struct autofs_node *anp)
629 struct autofs_node *parent;
631 AUTOFS_ASSERT_XLOCKED(anp->an_mount);
632 KASSERT(RB_EMPTY(&anp->an_children), ("have children"));
634 callout_drain(&anp->an_callout);
636 parent = anp->an_parent;
638 RB_REMOVE(autofs_node_tree, &parent->an_children, anp);
639 sx_destroy(&anp->an_vnode_lock);
640 free(anp->an_name, M_AUTOFS);
641 uma_zfree(autofs_node_zone, anp);
645 autofs_node_vn(struct autofs_node *anp, struct mount *mp, int flags,
651 AUTOFS_ASSERT_UNLOCKED(anp->an_mount);
653 sx_xlock(&anp->an_vnode_lock);
657 error = vget(vp, flags | LK_RETRY);
659 AUTOFS_WARN("vget failed with error %d", error);
660 sx_xunlock(&anp->an_vnode_lock);
663 if (VN_IS_DOOMED(vp)) {
665 * We got forcibly unmounted.
667 AUTOFS_DEBUG("doomed vnode");
668 sx_xunlock(&anp->an_vnode_lock);
675 sx_xunlock(&anp->an_vnode_lock);
679 error = getnewvnode("autofs", mp, &autofs_vnodeops, &vp);
681 sx_xunlock(&anp->an_vnode_lock);
685 error = vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
687 sx_xunlock(&anp->an_vnode_lock);
693 if (anp->an_parent == NULL)
694 vp->v_vflag |= VV_ROOT;
699 error = insmntque(vp, mp);
701 AUTOFS_DEBUG("insmntque() failed with error %d", error);
702 sx_xunlock(&anp->an_vnode_lock);
706 KASSERT(anp->an_vnode == NULL, ("lost race"));
709 sx_xunlock(&anp->an_vnode_lock);