/*- * SPDX-License-Identifier: BSD-2-Clause * * Copyright (c) 2014 The FreeBSD Foundation * * This software was developed by Edward Tomasz Napierala under sponsorship * from the FreeBSD Foundation. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include static int autofs_trigger_vn(struct vnode *vp, const char *path, int pathlen, struct vnode **newvp); extern struct autofs_softc *autofs_softc; static int autofs_access(struct vop_access_args *ap) { /* * Nothing to do here; the only kind of access control * needed is in autofs_mkdir(). */ return (0); } static int autofs_getattr(struct vop_getattr_args *ap) { struct vnode *vp, *newvp; struct autofs_node *anp; struct mount *mp; struct vattr *vap; int error; vp = ap->a_vp; anp = vp->v_data; mp = vp->v_mount; vap = ap->a_vap; KASSERT(ap->a_vp->v_type == VDIR, ("!VDIR")); /* * The reason we must do this is that some tree-walking software, * namely fts(3), assumes that stat(".") results will not change * between chdir("subdir") and chdir(".."), and fails with ENOENT * otherwise. */ if (autofs_mount_on_stat && autofs_cached(anp, NULL, 0) == false && autofs_ignore_thread(curthread) == false) { error = autofs_trigger_vn(vp, "", 0, &newvp); if (error != 0) return (error); if (newvp != NULL) { error = VOP_GETATTR(newvp, ap->a_vap, ap->a_cred); vput(newvp); return (error); } } vap->va_type = VDIR; vap->va_mode = 0755; vap->va_nlink = 3; /* XXX */ vap->va_uid = 0; vap->va_gid = 0; vap->va_rdev = NODEV; vap->va_fsid = mp->mnt_stat.f_fsid.val[0]; vap->va_fileid = anp->an_fileno; vap->va_size = S_BLKSIZE; vap->va_blocksize = S_BLKSIZE; vap->va_mtime = anp->an_ctime; vap->va_atime = anp->an_ctime; vap->va_ctime = anp->an_ctime; vap->va_birthtime = anp->an_ctime; vap->va_gen = 0; vap->va_flags = 0; vap->va_rdev = 0; vap->va_bytes = S_BLKSIZE; vap->va_filerev = 0; vap->va_spare = 0; return (0); } /* * Unlock the vnode, request automountd(8) action, and then lock it back. * If anything got mounted on top of the vnode, return the new filesystem's * root vnode in 'newvp', locked. */ static int autofs_trigger_vn(struct vnode *vp, const char *path, int pathlen, struct vnode **newvp) { struct autofs_node *anp; int error, lock_flags; anp = vp->v_data; /* * Release the vnode lock, so that other operations, in partcular * mounting a filesystem on top of it, can proceed. Increase use * count, to prevent the vnode from being deallocated and to prevent * filesystem from being unmounted. */ lock_flags = VOP_ISLOCKED(vp); vref(vp); VOP_UNLOCK(vp); sx_xlock(&autofs_softc->sc_lock); /* * XXX: Workaround for mounting the same thing multiple times; revisit. */ if (vp->v_mountedhere != NULL) { error = 0; goto mounted; } error = autofs_trigger(anp, path, pathlen); mounted: sx_xunlock(&autofs_softc->sc_lock); vn_lock(vp, lock_flags | LK_RETRY); vunref(vp); if (VN_IS_DOOMED(vp)) { AUTOFS_DEBUG("VIRF_DOOMED"); return (ENOENT); } if (error != 0) return (error); if (vp->v_mountedhere == NULL) { *newvp = NULL; return (0); } else { /* * If the operation that succeeded was mount, then mark * the node as non-cached. Otherwise, if someone unmounts * the filesystem before the cache times out, we will fail * to trigger. */ anp->an_cached = false; } error = VFS_ROOT(vp->v_mountedhere, lock_flags, newvp); if (error != 0) { AUTOFS_WARN("VFS_ROOT() failed with error %d", error); return (error); } return (0); } static int autofs_vget_callback(struct mount *mp, void *arg, int flags, struct vnode **vpp) { return (autofs_node_vn(arg, mp, flags, vpp)); } static int autofs_lookup(struct vop_lookup_args *ap) { struct vnode *dvp, *newvp, **vpp; struct mount *mp; struct autofs_mount *amp; struct autofs_node *anp, *child; struct componentname *cnp; int error; dvp = ap->a_dvp; vpp = ap->a_vpp; mp = dvp->v_mount; amp = VFSTOAUTOFS(mp); anp = dvp->v_data; cnp = ap->a_cnp; if (cnp->cn_flags & ISDOTDOT) { KASSERT(anp->an_parent != NULL, ("NULL parent")); /* * Note that in this case, dvp is the child vnode, and we * are looking up the parent vnode - exactly reverse from * normal operation. Unlocking dvp requires some rather * tricky unlock/relock dance to prevent mp from being freed; * use vn_vget_ino_gen() which takes care of all that. */ error = vn_vget_ino_gen(dvp, autofs_vget_callback, anp->an_parent, cnp->cn_lkflags, vpp); if (error != 0) { AUTOFS_WARN("vn_vget_ino_gen() failed with error %d", error); return (error); } return (error); } if (cnp->cn_namelen == 1 && cnp->cn_nameptr[0] == '.') { vref(dvp); *vpp = dvp; return (0); } if (autofs_cached(anp, cnp->cn_nameptr, cnp->cn_namelen) == false && autofs_ignore_thread(curthread) == false) { error = autofs_trigger_vn(dvp, cnp->cn_nameptr, cnp->cn_namelen, &newvp); if (error != 0) return (error); if (newvp != NULL) { /* * The target filesystem got automounted. * Let the lookup(9) go around with the same * path component. */ vput(newvp); return (ERELOOKUP); } } AUTOFS_SLOCK(amp); error = autofs_node_find(anp, cnp->cn_nameptr, cnp->cn_namelen, &child); if (error != 0) { if ((cnp->cn_flags & ISLASTCN) && cnp->cn_nameiop == CREATE) { AUTOFS_SUNLOCK(amp); return (EJUSTRETURN); } AUTOFS_SUNLOCK(amp); return (ENOENT); } /* * XXX: Dropping the node here is ok, because we never remove nodes. */ AUTOFS_SUNLOCK(amp); error = autofs_node_vn(child, mp, cnp->cn_lkflags, vpp); if (error != 0) { if ((cnp->cn_flags & ISLASTCN) && cnp->cn_nameiop == CREATE) return (EJUSTRETURN); return (error); } return (0); } static int autofs_mkdir(struct vop_mkdir_args *ap) { struct vnode *vp; struct autofs_node *anp; struct autofs_mount *amp; struct autofs_node *child; int error; vp = ap->a_dvp; anp = vp->v_data; amp = VFSTOAUTOFS(vp->v_mount); /* * Do not allow mkdir() if the calling thread is not * automountd(8) descendant. */ if (autofs_ignore_thread(curthread) == false) return (EPERM); AUTOFS_XLOCK(amp); error = autofs_node_new(anp, amp, ap->a_cnp->cn_nameptr, ap->a_cnp->cn_namelen, &child); if (error != 0) { AUTOFS_XUNLOCK(amp); return (error); } AUTOFS_XUNLOCK(amp); error = autofs_node_vn(child, vp->v_mount, LK_EXCLUSIVE, ap->a_vpp); return (error); } static int autofs_print(struct vop_print_args *ap) { struct vnode *vp; struct autofs_node *anp; vp = ap->a_vp; anp = vp->v_data; printf(" name \"%s\", fileno %d, cached %d, wildcards %d\n", anp->an_name, anp->an_fileno, anp->an_cached, anp->an_wildcards); return (0); } /* * Write out a single 'struct dirent', based on 'name' and 'fileno' arguments. */ static int autofs_readdir_one(struct uio *uio, const char *name, int fileno, size_t *reclenp) { struct dirent dirent; size_t namlen, reclen; int error; namlen = strlen(name); reclen = _GENERIC_DIRLEN(namlen); if (reclenp != NULL) *reclenp = reclen; if (uio == NULL) return (0); if (uio->uio_resid < reclen) return (EINVAL); dirent.d_fileno = fileno; dirent.d_off = uio->uio_offset + reclen; dirent.d_reclen = reclen; dirent.d_type = DT_DIR; dirent.d_namlen = namlen; memcpy(dirent.d_name, name, namlen); dirent_terminate(&dirent); error = uiomove(&dirent, reclen, uio); return (error); } static size_t autofs_dirent_reclen(const char *name) { size_t reclen; (void)autofs_readdir_one(NULL, name, -1, &reclen); return (reclen); } static int autofs_readdir(struct vop_readdir_args *ap) { struct vnode *vp, *newvp; struct autofs_mount *amp; struct autofs_node *anp, *child; struct uio *uio; size_t reclen, reclens; ssize_t initial_resid; int error; vp = ap->a_vp; amp = VFSTOAUTOFS(vp->v_mount); anp = vp->v_data; uio = ap->a_uio; initial_resid = ap->a_uio->uio_resid; KASSERT(vp->v_type == VDIR, ("!VDIR")); if (autofs_cached(anp, NULL, 0) == false && autofs_ignore_thread(curthread) == false) { error = autofs_trigger_vn(vp, "", 0, &newvp); if (error != 0) return (error); if (newvp != NULL) { error = VOP_READDIR(newvp, ap->a_uio, ap->a_cred, ap->a_eofflag, ap->a_ncookies, ap->a_cookies); vput(newvp); return (error); } } if (uio->uio_offset < 0) return (EINVAL); if (ap->a_eofflag != NULL) *ap->a_eofflag = FALSE; /* * Write out the directory entry for ".". This is conditional * on the current offset into the directory; same applies to the * other two cases below. */ if (uio->uio_offset == 0) { error = autofs_readdir_one(uio, ".", anp->an_fileno, &reclen); if (error != 0) goto out; } reclens = autofs_dirent_reclen("."); /* * Write out the directory entry for "..". */ if (uio->uio_offset <= reclens) { if (uio->uio_offset != reclens) return (EINVAL); if (anp->an_parent == NULL) { error = autofs_readdir_one(uio, "..", anp->an_fileno, &reclen); } else { error = autofs_readdir_one(uio, "..", anp->an_parent->an_fileno, &reclen); } if (error != 0) goto out; } reclens += autofs_dirent_reclen(".."); /* * Write out the directory entries for subdirectories. */ AUTOFS_SLOCK(amp); RB_FOREACH(child, autofs_node_tree, &anp->an_children) { /* * Check the offset to skip entries returned by previous * calls to getdents(). */ if (uio->uio_offset > reclens) { reclens += autofs_dirent_reclen(child->an_name); continue; } /* * Prevent seeking into the middle of dirent. */ if (uio->uio_offset != reclens) { AUTOFS_SUNLOCK(amp); return (EINVAL); } error = autofs_readdir_one(uio, child->an_name, child->an_fileno, &reclen); reclens += reclen; if (error != 0) { AUTOFS_SUNLOCK(amp); goto out; } } AUTOFS_SUNLOCK(amp); if (ap->a_eofflag != NULL) *ap->a_eofflag = TRUE; return (0); out: /* * Return error if the initial buffer was too small to do anything. */ if (uio->uio_resid == initial_resid) return (error); /* * Don't return an error if we managed to copy out some entries. */ if (uio->uio_resid < reclen) return (0); return (error); } static int autofs_reclaim(struct vop_reclaim_args *ap) { struct vnode *vp; struct autofs_node *anp; vp = ap->a_vp; anp = vp->v_data; /* * We do not free autofs_node here; instead we are * destroying them in autofs_node_delete(). */ sx_xlock(&anp->an_vnode_lock); anp->an_vnode = NULL; vp->v_data = NULL; sx_xunlock(&anp->an_vnode_lock); return (0); } struct vop_vector autofs_vnodeops = { .vop_default = &default_vnodeops, .vop_access = autofs_access, .vop_lookup = autofs_lookup, .vop_create = VOP_EOPNOTSUPP, .vop_getattr = autofs_getattr, .vop_link = VOP_EOPNOTSUPP, .vop_mkdir = autofs_mkdir, .vop_mknod = VOP_EOPNOTSUPP, .vop_print = autofs_print, .vop_read = VOP_EOPNOTSUPP, .vop_readdir = autofs_readdir, .vop_remove = VOP_EOPNOTSUPP, .vop_rename = VOP_EOPNOTSUPP, .vop_rmdir = VOP_EOPNOTSUPP, .vop_setattr = VOP_EOPNOTSUPP, .vop_symlink = VOP_EOPNOTSUPP, .vop_write = VOP_EOPNOTSUPP, .vop_reclaim = autofs_reclaim, }; VFS_VOP_VECTOR_REGISTER(autofs_vnodeops); int autofs_node_new(struct autofs_node *parent, struct autofs_mount *amp, const char *name, int namelen, struct autofs_node **anpp) { struct autofs_node *anp; if (parent != NULL) { AUTOFS_ASSERT_XLOCKED(parent->an_mount); KASSERT(autofs_node_find(parent, name, namelen, NULL) == ENOENT, ("node \"%s\" already exists", name)); } anp = uma_zalloc(autofs_node_zone, M_WAITOK | M_ZERO); if (namelen >= 0) anp->an_name = strndup(name, namelen, M_AUTOFS); else anp->an_name = strdup(name, M_AUTOFS); anp->an_fileno = atomic_fetchadd_int(&->am_last_fileno, 1); callout_init(&anp->an_callout, 1); /* * The reason for SX_NOWITNESS here is that witness(4) * cannot tell vnodes apart, so the following perfectly * valid lock order... * * vnode lock A -> autofsvlk B -> vnode lock B * * ... gets reported as a LOR. */ sx_init_flags(&anp->an_vnode_lock, "autofsvlk", SX_NOWITNESS); getnanotime(&anp->an_ctime); anp->an_parent = parent; anp->an_mount = amp; if (parent != NULL) RB_INSERT(autofs_node_tree, &parent->an_children, anp); RB_INIT(&anp->an_children); *anpp = anp; return (0); } int autofs_node_find(struct autofs_node *parent, const char *name, int namelen, struct autofs_node **anpp) { struct autofs_node *anp, find; int error; AUTOFS_ASSERT_LOCKED(parent->an_mount); if (namelen >= 0) find.an_name = strndup(name, namelen, M_AUTOFS); else find.an_name = strdup(name, M_AUTOFS); anp = RB_FIND(autofs_node_tree, &parent->an_children, &find); if (anp != NULL) { error = 0; if (anpp != NULL) *anpp = anp; } else { error = ENOENT; } free(find.an_name, M_AUTOFS); return (error); } void autofs_node_delete(struct autofs_node *anp) { struct autofs_node *parent; AUTOFS_ASSERT_XLOCKED(anp->an_mount); KASSERT(RB_EMPTY(&anp->an_children), ("have children")); callout_drain(&anp->an_callout); parent = anp->an_parent; if (parent != NULL) RB_REMOVE(autofs_node_tree, &parent->an_children, anp); sx_destroy(&anp->an_vnode_lock); free(anp->an_name, M_AUTOFS); uma_zfree(autofs_node_zone, anp); } int autofs_node_vn(struct autofs_node *anp, struct mount *mp, int flags, struct vnode **vpp) { struct vnode *vp; int error; AUTOFS_ASSERT_UNLOCKED(anp->an_mount); sx_xlock(&anp->an_vnode_lock); vp = anp->an_vnode; if (vp != NULL) { error = vget(vp, flags | LK_RETRY); if (error != 0) { AUTOFS_WARN("vget failed with error %d", error); sx_xunlock(&anp->an_vnode_lock); return (error); } if (VN_IS_DOOMED(vp)) { /* * We got forcibly unmounted. */ AUTOFS_DEBUG("doomed vnode"); sx_xunlock(&anp->an_vnode_lock); vput(vp); return (ENOENT); } *vpp = vp; sx_xunlock(&anp->an_vnode_lock); return (0); } error = getnewvnode("autofs", mp, &autofs_vnodeops, &vp); if (error != 0) { sx_xunlock(&anp->an_vnode_lock); return (error); } vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); vp->v_type = VDIR; if (anp->an_parent == NULL) vp->v_vflag |= VV_ROOT; vp->v_data = anp; VN_LOCK_ASHARE(vp); error = insmntque(vp, mp); if (error != 0) { AUTOFS_DEBUG("insmntque() failed with error %d", error); sx_xunlock(&anp->an_vnode_lock); return (error); } KASSERT(anp->an_vnode == NULL, ("lost race")); anp->an_vnode = vp; sx_xunlock(&anp->an_vnode_lock); vn_set_state(vp, VSTATE_CONSTRUCTED); *vpp = vp; return (0); }