PR: 269780 Reported by: Dan Gohman <dev@sunfishcode.online> Reviewed by: emaste, markj Sponsored by: The FreeBSD Foundation MFC after: 1 week Differential revision: https://reviews.freebsd.org/D39773
1688 lines
44 KiB
C
1688 lines
44 KiB
C
/*-
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* SPDX-License-Identifier: BSD-3-Clause
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*
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* Copyright (c) 1982, 1986, 1989, 1993
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* The Regents of the University of California. All rights reserved.
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* (c) UNIX System Laboratories, Inc.
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* All or some portions of this file are derived from material licensed
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* to the University of California by American Telephone and Telegraph
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* Co. or Unix System Laboratories, Inc. and are reproduced herein with
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* the permission of UNIX System Laboratories, Inc.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @(#)vfs_lookup.c 8.4 (Berkeley) 2/16/94
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include "opt_capsicum.h"
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#include "opt_ktrace.h"
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/dirent.h>
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#include <sys/kernel.h>
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#include <sys/capsicum.h>
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#include <sys/fcntl.h>
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#include <sys/jail.h>
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#include <sys/lock.h>
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#include <sys/mutex.h>
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#include <sys/namei.h>
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#include <sys/vnode.h>
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#include <sys/mount.h>
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#include <sys/filedesc.h>
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#include <sys/proc.h>
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#include <sys/sdt.h>
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#include <sys/syscallsubr.h>
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#include <sys/sysctl.h>
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#ifdef KTRACE
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#include <sys/ktrace.h>
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#endif
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#ifdef INVARIANTS
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#include <machine/_inttypes.h>
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#endif
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#include <security/audit/audit.h>
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#include <security/mac/mac_framework.h>
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#include <vm/uma.h>
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#define NAMEI_DIAGNOSTIC 1
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#undef NAMEI_DIAGNOSTIC
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#ifdef INVARIANTS
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static void NDVALIDATE_impl(struct nameidata *, int);
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#define NDVALIDATE(ndp) NDVALIDATE_impl(ndp, __LINE__)
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#else
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#define NDVALIDATE(ndp)
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#endif
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SDT_PROVIDER_DEFINE(vfs);
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SDT_PROBE_DEFINE4(vfs, namei, lookup, entry, "struct vnode *", "char *",
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"unsigned long", "bool");
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SDT_PROBE_DEFINE4(vfs, namei, lookup, return, "int", "struct vnode *", "bool",
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"struct nameidata");
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/* Allocation zone for namei. */
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uma_zone_t namei_zone;
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/* Placeholder vnode for mp traversal. */
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static struct vnode *vp_crossmp;
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static int
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crossmp_vop_islocked(struct vop_islocked_args *ap)
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{
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return (LK_SHARED);
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}
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static int
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crossmp_vop_lock1(struct vop_lock1_args *ap)
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{
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struct vnode *vp;
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struct lock *lk __diagused;
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int flags;
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vp = ap->a_vp;
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lk = vp->v_vnlock;
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flags = ap->a_flags;
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KASSERT((flags & (LK_SHARED | LK_NOWAIT)) == (LK_SHARED | LK_NOWAIT),
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("%s: invalid lock request 0x%x for crossmp", __func__, flags));
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if ((flags & LK_INTERLOCK) != 0)
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VI_UNLOCK(vp);
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LOCK_LOG_LOCK("SLOCK", &lk->lock_object, 0, 0, ap->a_file, ap->a_line);
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return (0);
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}
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static int
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crossmp_vop_unlock(struct vop_unlock_args *ap)
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{
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struct vnode *vp;
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struct lock *lk __diagused;
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vp = ap->a_vp;
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lk = vp->v_vnlock;
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LOCK_LOG_LOCK("SUNLOCK", &lk->lock_object, 0, 0, LOCK_FILE,
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LOCK_LINE);
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return (0);
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}
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static struct vop_vector crossmp_vnodeops = {
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.vop_default = &default_vnodeops,
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.vop_islocked = crossmp_vop_islocked,
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.vop_lock1 = crossmp_vop_lock1,
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.vop_unlock = crossmp_vop_unlock,
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};
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/*
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* VFS_VOP_VECTOR_REGISTER(crossmp_vnodeops) is not used here since the vnode
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* gets allocated early. See nameiinit for the direct call below.
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*/
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struct nameicap_tracker {
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struct vnode *dp;
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TAILQ_ENTRY(nameicap_tracker) nm_link;
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};
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/* Zone for cap mode tracker elements used for dotdot capability checks. */
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MALLOC_DEFINE(M_NAMEITRACKER, "namei_tracker", "namei tracking for dotdot");
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static void
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nameiinit(void *dummy __unused)
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{
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namei_zone = uma_zcreate("NAMEI", MAXPATHLEN, NULL, NULL, NULL, NULL,
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UMA_ALIGN_PTR, 0);
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vfs_vector_op_register(&crossmp_vnodeops);
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getnewvnode("crossmp", NULL, &crossmp_vnodeops, &vp_crossmp);
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vp_crossmp->v_state = VSTATE_CONSTRUCTED;
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vp_crossmp->v_irflag |= VIRF_CROSSMP;
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}
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SYSINIT(vfs, SI_SUB_VFS, SI_ORDER_SECOND, nameiinit, NULL);
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static int lookup_cap_dotdot = 1;
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SYSCTL_INT(_vfs, OID_AUTO, lookup_cap_dotdot, CTLFLAG_RWTUN,
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&lookup_cap_dotdot, 0,
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"enables \"..\" components in path lookup in capability mode");
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static int lookup_cap_dotdot_nonlocal = 1;
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SYSCTL_INT(_vfs, OID_AUTO, lookup_cap_dotdot_nonlocal, CTLFLAG_RWTUN,
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&lookup_cap_dotdot_nonlocal, 0,
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"enables \"..\" components in path lookup in capability mode "
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"on non-local mount");
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static void
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nameicap_tracker_add(struct nameidata *ndp, struct vnode *dp)
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{
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struct nameicap_tracker *nt;
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if ((ndp->ni_lcf & NI_LCF_CAP_DOTDOT) == 0 || dp->v_type != VDIR)
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return;
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nt = TAILQ_LAST(&ndp->ni_cap_tracker, nameicap_tracker_head);
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if (nt != NULL && nt->dp == dp)
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return;
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nt = malloc(sizeof(*nt), M_NAMEITRACKER, M_WAITOK);
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vhold(dp);
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nt->dp = dp;
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TAILQ_INSERT_TAIL(&ndp->ni_cap_tracker, nt, nm_link);
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}
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static void
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nameicap_cleanup_from(struct nameidata *ndp, struct nameicap_tracker *first)
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{
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struct nameicap_tracker *nt, *nt1;
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nt = first;
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TAILQ_FOREACH_FROM_SAFE(nt, &ndp->ni_cap_tracker, nm_link, nt1) {
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TAILQ_REMOVE(&ndp->ni_cap_tracker, nt, nm_link);
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vdrop(nt->dp);
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free(nt, M_NAMEITRACKER);
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}
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}
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static void
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nameicap_cleanup(struct nameidata *ndp)
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{
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KASSERT(TAILQ_EMPTY(&ndp->ni_cap_tracker) ||
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(ndp->ni_lcf & NI_LCF_CAP_DOTDOT) != 0, ("not strictrelative"));
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nameicap_cleanup_from(ndp, NULL);
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}
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/*
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* For dotdot lookups in capability mode, only allow the component
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* lookup to succeed if the resulting directory was already traversed
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* during the operation. This catches situations where already
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* traversed directory is moved to different parent, and then we walk
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* over it with dotdots.
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*
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* Also allow to force failure of dotdot lookups for non-local
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* filesystems, where external agents might assist local lookups to
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* escape the compartment.
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*/
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static int
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nameicap_check_dotdot(struct nameidata *ndp, struct vnode *dp)
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{
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struct nameicap_tracker *nt;
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struct mount *mp;
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if (dp == NULL || dp->v_type != VDIR || (ndp->ni_lcf &
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NI_LCF_STRICTRELATIVE) == 0)
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return (0);
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if ((ndp->ni_lcf & NI_LCF_CAP_DOTDOT) == 0)
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return (ENOTCAPABLE);
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mp = dp->v_mount;
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if (lookup_cap_dotdot_nonlocal == 0 && mp != NULL &&
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(mp->mnt_flag & MNT_LOCAL) == 0)
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return (ENOTCAPABLE);
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TAILQ_FOREACH_REVERSE(nt, &ndp->ni_cap_tracker, nameicap_tracker_head,
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nm_link) {
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if (dp == nt->dp) {
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nt = TAILQ_NEXT(nt, nm_link);
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if (nt != NULL)
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nameicap_cleanup_from(ndp, nt);
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return (0);
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}
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}
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return (ENOTCAPABLE);
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}
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static void
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namei_cleanup_cnp(struct componentname *cnp)
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{
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uma_zfree(namei_zone, cnp->cn_pnbuf);
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cnp->cn_pnbuf = NULL;
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cnp->cn_nameptr = NULL;
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}
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static int
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namei_handle_root(struct nameidata *ndp, struct vnode **dpp)
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{
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struct componentname *cnp;
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cnp = &ndp->ni_cnd;
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if ((ndp->ni_lcf & NI_LCF_STRICTRELATIVE) != 0) {
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#ifdef KTRACE
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if (KTRPOINT(curthread, KTR_CAPFAIL))
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ktrcapfail(CAPFAIL_LOOKUP, NULL, NULL);
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#endif
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return (ENOTCAPABLE);
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}
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while (*(cnp->cn_nameptr) == '/') {
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cnp->cn_nameptr++;
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ndp->ni_pathlen--;
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}
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*dpp = ndp->ni_rootdir;
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vrefact(*dpp);
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return (0);
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}
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static int
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namei_setup(struct nameidata *ndp, struct vnode **dpp, struct pwd **pwdp)
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{
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struct componentname *cnp;
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struct thread *td;
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struct pwd *pwd;
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int error;
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bool startdir_used;
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cnp = &ndp->ni_cnd;
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td = curthread;
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startdir_used = false;
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*pwdp = NULL;
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*dpp = NULL;
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#ifdef CAPABILITY_MODE
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/*
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* In capability mode, lookups must be restricted to happen in
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* the subtree with the root specified by the file descriptor:
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* - The root must be real file descriptor, not the pseudo-descriptor
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* AT_FDCWD.
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* - The passed path must be relative and not absolute.
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* - If lookup_cap_dotdot is disabled, path must not contain the
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* '..' components.
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* - If lookup_cap_dotdot is enabled, we verify that all '..'
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* components lookups result in the directories which were
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* previously walked by us, which prevents an escape from
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* the relative root.
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*/
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if (IN_CAPABILITY_MODE(td) && (cnp->cn_flags & NOCAPCHECK) == 0) {
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ndp->ni_lcf |= NI_LCF_STRICTRELATIVE;
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ndp->ni_resflags |= NIRES_STRICTREL;
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if (ndp->ni_dirfd == AT_FDCWD) {
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#ifdef KTRACE
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if (KTRPOINT(td, KTR_CAPFAIL))
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ktrcapfail(CAPFAIL_LOOKUP, NULL, NULL);
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#endif
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return (ECAPMODE);
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}
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}
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#endif
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error = 0;
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/*
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* Get starting point for the translation.
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*/
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pwd = pwd_hold(td);
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/*
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* The reference on ni_rootdir is acquired in the block below to avoid
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* back-to-back atomics for absolute lookups.
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*/
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ndp->ni_rootdir = pwd->pwd_rdir;
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ndp->ni_topdir = pwd->pwd_jdir;
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if (cnp->cn_pnbuf[0] == '/') {
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ndp->ni_resflags |= NIRES_ABS;
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error = namei_handle_root(ndp, dpp);
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} else {
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if (ndp->ni_startdir != NULL) {
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*dpp = ndp->ni_startdir;
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startdir_used = true;
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} else if (ndp->ni_dirfd == AT_FDCWD) {
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*dpp = pwd->pwd_cdir;
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vrefact(*dpp);
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} else {
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if (cnp->cn_flags & AUDITVNODE1)
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AUDIT_ARG_ATFD1(ndp->ni_dirfd);
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if (cnp->cn_flags & AUDITVNODE2)
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AUDIT_ARG_ATFD2(ndp->ni_dirfd);
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error = fgetvp_lookup(ndp->ni_dirfd, ndp, dpp);
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}
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if (error == 0 && (*dpp)->v_type != VDIR &&
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(cnp->cn_pnbuf[0] != '\0' ||
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(cnp->cn_flags & EMPTYPATH) == 0))
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error = ENOTDIR;
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}
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if (error == 0 && (cnp->cn_flags & RBENEATH) != 0) {
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if (cnp->cn_pnbuf[0] == '/') {
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error = ENOTCAPABLE;
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} else if ((ndp->ni_lcf & NI_LCF_STRICTRELATIVE) == 0) {
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ndp->ni_lcf |= NI_LCF_STRICTRELATIVE |
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NI_LCF_CAP_DOTDOT;
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}
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}
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|
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/*
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* If we are auditing the kernel pathname, save the user pathname.
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*/
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if (cnp->cn_flags & AUDITVNODE1)
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AUDIT_ARG_UPATH1_VP(td, ndp->ni_rootdir, *dpp, cnp->cn_pnbuf);
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if (cnp->cn_flags & AUDITVNODE2)
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AUDIT_ARG_UPATH2_VP(td, ndp->ni_rootdir, *dpp, cnp->cn_pnbuf);
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if (ndp->ni_startdir != NULL && !startdir_used)
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vrele(ndp->ni_startdir);
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if (error != 0) {
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if (*dpp != NULL)
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vrele(*dpp);
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pwd_drop(pwd);
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return (error);
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}
|
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if ((ndp->ni_lcf & NI_LCF_STRICTRELATIVE) != 0 &&
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lookup_cap_dotdot != 0)
|
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ndp->ni_lcf |= NI_LCF_CAP_DOTDOT;
|
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SDT_PROBE4(vfs, namei, lookup, entry, *dpp, cnp->cn_pnbuf,
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cnp->cn_flags, false);
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*pwdp = pwd;
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return (0);
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}
|
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|
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static int
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namei_getpath(struct nameidata *ndp)
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{
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struct componentname *cnp;
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int error;
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|
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cnp = &ndp->ni_cnd;
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|
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/*
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* Get a buffer for the name to be translated, and copy the
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* name into the buffer.
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*/
|
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cnp->cn_pnbuf = uma_zalloc(namei_zone, M_WAITOK);
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if (ndp->ni_segflg == UIO_SYSSPACE) {
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error = copystr(ndp->ni_dirp, cnp->cn_pnbuf, MAXPATHLEN,
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&ndp->ni_pathlen);
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} else {
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error = copyinstr(ndp->ni_dirp, cnp->cn_pnbuf, MAXPATHLEN,
|
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&ndp->ni_pathlen);
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}
|
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|
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return (error);
|
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}
|
|
|
|
static int
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namei_emptypath(struct nameidata *ndp)
|
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{
|
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struct componentname *cnp;
|
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struct pwd *pwd;
|
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struct vnode *dp;
|
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int error;
|
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|
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cnp = &ndp->ni_cnd;
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MPASS(*cnp->cn_pnbuf == '\0');
|
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MPASS((cnp->cn_flags & EMPTYPATH) != 0);
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MPASS((cnp->cn_flags & (LOCKPARENT | WANTPARENT)) == 0);
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|
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ndp->ni_resflags |= NIRES_EMPTYPATH;
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error = namei_setup(ndp, &dp, &pwd);
|
|
if (error != 0) {
|
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goto errout;
|
|
}
|
|
|
|
/*
|
|
* Usecount on dp already provided by namei_setup.
|
|
*/
|
|
ndp->ni_vp = dp;
|
|
pwd_drop(pwd);
|
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NDVALIDATE(ndp);
|
|
if ((cnp->cn_flags & LOCKLEAF) != 0) {
|
|
VOP_LOCK(dp, (cnp->cn_flags & LOCKSHARED) != 0 ?
|
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LK_SHARED : LK_EXCLUSIVE);
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|
if (VN_IS_DOOMED(dp)) {
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vput(dp);
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error = ENOENT;
|
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goto errout;
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|
}
|
|
}
|
|
SDT_PROBE4(vfs, namei, lookup, return, 0, ndp->ni_vp, false, ndp);
|
|
return (0);
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|
|
errout:
|
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SDT_PROBE4(vfs, namei, lookup, return, error, NULL, false, ndp);
|
|
namei_cleanup_cnp(cnp);
|
|
return (error);
|
|
}
|
|
|
|
static int __noinline
|
|
namei_follow_link(struct nameidata *ndp)
|
|
{
|
|
char *cp;
|
|
struct iovec aiov;
|
|
struct uio auio;
|
|
struct componentname *cnp;
|
|
struct thread *td;
|
|
int error, linklen;
|
|
|
|
error = 0;
|
|
cnp = &ndp->ni_cnd;
|
|
td = curthread;
|
|
|
|
if (ndp->ni_loopcnt++ >= MAXSYMLINKS) {
|
|
error = ELOOP;
|
|
goto out;
|
|
}
|
|
#ifdef MAC
|
|
if ((cnp->cn_flags & NOMACCHECK) == 0) {
|
|
error = mac_vnode_check_readlink(td->td_ucred, ndp->ni_vp);
|
|
if (error != 0)
|
|
goto out;
|
|
}
|
|
#endif
|
|
if (ndp->ni_pathlen > 1)
|
|
cp = uma_zalloc(namei_zone, M_WAITOK);
|
|
else
|
|
cp = cnp->cn_pnbuf;
|
|
aiov.iov_base = cp;
|
|
aiov.iov_len = MAXPATHLEN;
|
|
auio.uio_iov = &aiov;
|
|
auio.uio_iovcnt = 1;
|
|
auio.uio_offset = 0;
|
|
auio.uio_rw = UIO_READ;
|
|
auio.uio_segflg = UIO_SYSSPACE;
|
|
auio.uio_td = td;
|
|
auio.uio_resid = MAXPATHLEN;
|
|
error = VOP_READLINK(ndp->ni_vp, &auio, cnp->cn_cred);
|
|
if (error != 0) {
|
|
if (ndp->ni_pathlen > 1)
|
|
uma_zfree(namei_zone, cp);
|
|
goto out;
|
|
}
|
|
linklen = MAXPATHLEN - auio.uio_resid;
|
|
if (linklen == 0) {
|
|
if (ndp->ni_pathlen > 1)
|
|
uma_zfree(namei_zone, cp);
|
|
error = ENOENT;
|
|
goto out;
|
|
}
|
|
if (linklen + ndp->ni_pathlen > MAXPATHLEN) {
|
|
if (ndp->ni_pathlen > 1)
|
|
uma_zfree(namei_zone, cp);
|
|
error = ENAMETOOLONG;
|
|
goto out;
|
|
}
|
|
if (ndp->ni_pathlen > 1) {
|
|
bcopy(ndp->ni_next, cp + linklen, ndp->ni_pathlen);
|
|
uma_zfree(namei_zone, cnp->cn_pnbuf);
|
|
cnp->cn_pnbuf = cp;
|
|
} else
|
|
cnp->cn_pnbuf[linklen] = '\0';
|
|
ndp->ni_pathlen += linklen;
|
|
out:
|
|
return (error);
|
|
}
|
|
|
|
/*
|
|
* Convert a pathname into a pointer to a locked vnode.
|
|
*
|
|
* The FOLLOW flag is set when symbolic links are to be followed
|
|
* when they occur at the end of the name translation process.
|
|
* Symbolic links are always followed for all other pathname
|
|
* components other than the last.
|
|
*
|
|
* The segflg defines whether the name is to be copied from user
|
|
* space or kernel space.
|
|
*
|
|
* Overall outline of namei:
|
|
*
|
|
* copy in name
|
|
* get starting directory
|
|
* while (!done && !error) {
|
|
* call lookup to search path.
|
|
* if symbolic link, massage name in buffer and continue
|
|
* }
|
|
*/
|
|
int
|
|
namei(struct nameidata *ndp)
|
|
{
|
|
struct vnode *dp; /* the directory we are searching */
|
|
struct componentname *cnp;
|
|
struct thread *td;
|
|
struct pwd *pwd;
|
|
int error;
|
|
enum cache_fpl_status status;
|
|
|
|
cnp = &ndp->ni_cnd;
|
|
td = curthread;
|
|
#ifdef INVARIANTS
|
|
KASSERT((ndp->ni_debugflags & NAMEI_DBG_CALLED) == 0,
|
|
("%s: repeated call to namei without NDREINIT", __func__));
|
|
KASSERT(ndp->ni_debugflags == NAMEI_DBG_INITED,
|
|
("%s: bad debugflags %d", __func__, ndp->ni_debugflags));
|
|
ndp->ni_debugflags |= NAMEI_DBG_CALLED;
|
|
if (ndp->ni_startdir != NULL)
|
|
ndp->ni_debugflags |= NAMEI_DBG_HADSTARTDIR;
|
|
if (cnp->cn_flags & FAILIFEXISTS) {
|
|
KASSERT(cnp->cn_nameiop == CREATE,
|
|
("%s: FAILIFEXISTS passed for op %d", __func__, cnp->cn_nameiop));
|
|
/*
|
|
* The limitation below is to restrict hairy corner cases.
|
|
*/
|
|
KASSERT((cnp->cn_flags & (LOCKPARENT | LOCKLEAF)) == LOCKPARENT,
|
|
("%s: FAILIFEXISTS must be passed with LOCKPARENT and without LOCKLEAF",
|
|
__func__));
|
|
}
|
|
#endif
|
|
ndp->ni_cnd.cn_cred = td->td_ucred;
|
|
KASSERT(ndp->ni_resflags == 0, ("%s: garbage in ni_resflags: %x\n",
|
|
__func__, ndp->ni_resflags));
|
|
KASSERT(cnp->cn_cred && td->td_proc, ("namei: bad cred/proc"));
|
|
KASSERT((cnp->cn_flags & NAMEI_INTERNAL_FLAGS) == 0,
|
|
("namei: unexpected flags: %" PRIx64 "\n",
|
|
cnp->cn_flags & NAMEI_INTERNAL_FLAGS));
|
|
if (cnp->cn_flags & NOCACHE)
|
|
KASSERT(cnp->cn_nameiop != LOOKUP,
|
|
("%s: NOCACHE passed with LOOKUP", __func__));
|
|
MPASS(ndp->ni_startdir == NULL || ndp->ni_startdir->v_type == VDIR ||
|
|
ndp->ni_startdir->v_type == VBAD);
|
|
|
|
ndp->ni_lcf = 0;
|
|
ndp->ni_loopcnt = 0;
|
|
ndp->ni_vp = NULL;
|
|
|
|
error = namei_getpath(ndp);
|
|
if (__predict_false(error != 0)) {
|
|
namei_cleanup_cnp(cnp);
|
|
SDT_PROBE4(vfs, namei, lookup, return, error, NULL,
|
|
false, ndp);
|
|
return (error);
|
|
}
|
|
|
|
cnp->cn_nameptr = cnp->cn_pnbuf;
|
|
|
|
#ifdef KTRACE
|
|
if (KTRPOINT(td, KTR_NAMEI)) {
|
|
ktrnamei(cnp->cn_pnbuf);
|
|
}
|
|
#endif
|
|
TSNAMEI(curthread->td_proc->p_pid, cnp->cn_pnbuf);
|
|
|
|
/*
|
|
* First try looking up the target without locking any vnodes.
|
|
*
|
|
* We may need to start from scratch or pick up where it left off.
|
|
*/
|
|
error = cache_fplookup(ndp, &status, &pwd);
|
|
switch (status) {
|
|
case CACHE_FPL_STATUS_UNSET:
|
|
__assert_unreachable();
|
|
break;
|
|
case CACHE_FPL_STATUS_HANDLED:
|
|
if (error == 0)
|
|
NDVALIDATE(ndp);
|
|
return (error);
|
|
case CACHE_FPL_STATUS_PARTIAL:
|
|
TAILQ_INIT(&ndp->ni_cap_tracker);
|
|
dp = ndp->ni_startdir;
|
|
break;
|
|
case CACHE_FPL_STATUS_DESTROYED:
|
|
ndp->ni_loopcnt = 0;
|
|
error = namei_getpath(ndp);
|
|
if (__predict_false(error != 0)) {
|
|
namei_cleanup_cnp(cnp);
|
|
return (error);
|
|
}
|
|
cnp->cn_nameptr = cnp->cn_pnbuf;
|
|
/* FALLTHROUGH */
|
|
case CACHE_FPL_STATUS_ABORTED:
|
|
TAILQ_INIT(&ndp->ni_cap_tracker);
|
|
MPASS(ndp->ni_lcf == 0);
|
|
if (*cnp->cn_pnbuf == '\0') {
|
|
if ((cnp->cn_flags & EMPTYPATH) != 0) {
|
|
return (namei_emptypath(ndp));
|
|
}
|
|
namei_cleanup_cnp(cnp);
|
|
SDT_PROBE4(vfs, namei, lookup, return, ENOENT, NULL,
|
|
false, ndp);
|
|
return (ENOENT);
|
|
}
|
|
error = namei_setup(ndp, &dp, &pwd);
|
|
if (error != 0) {
|
|
namei_cleanup_cnp(cnp);
|
|
return (error);
|
|
}
|
|
break;
|
|
}
|
|
|
|
/*
|
|
* Locked lookup.
|
|
*/
|
|
for (;;) {
|
|
ndp->ni_startdir = dp;
|
|
error = vfs_lookup(ndp);
|
|
if (error != 0)
|
|
goto out;
|
|
|
|
/*
|
|
* If not a symbolic link, we're done.
|
|
*/
|
|
if ((cnp->cn_flags & ISSYMLINK) == 0) {
|
|
SDT_PROBE4(vfs, namei, lookup, return, error,
|
|
ndp->ni_vp, false, ndp);
|
|
nameicap_cleanup(ndp);
|
|
pwd_drop(pwd);
|
|
NDVALIDATE(ndp);
|
|
return (0);
|
|
}
|
|
error = namei_follow_link(ndp);
|
|
if (error != 0)
|
|
break;
|
|
vput(ndp->ni_vp);
|
|
dp = ndp->ni_dvp;
|
|
/*
|
|
* Check if root directory should replace current directory.
|
|
*/
|
|
cnp->cn_nameptr = cnp->cn_pnbuf;
|
|
if (*(cnp->cn_nameptr) == '/') {
|
|
vrele(dp);
|
|
error = namei_handle_root(ndp, &dp);
|
|
if (error != 0)
|
|
goto out;
|
|
}
|
|
}
|
|
vput(ndp->ni_vp);
|
|
ndp->ni_vp = NULL;
|
|
vrele(ndp->ni_dvp);
|
|
out:
|
|
MPASS(error != 0);
|
|
SDT_PROBE4(vfs, namei, lookup, return, error, NULL, false, ndp);
|
|
namei_cleanup_cnp(cnp);
|
|
nameicap_cleanup(ndp);
|
|
pwd_drop(pwd);
|
|
return (error);
|
|
}
|
|
|
|
static int
|
|
compute_cn_lkflags(struct mount *mp, int lkflags, int cnflags)
|
|
{
|
|
|
|
if (mp == NULL || ((lkflags & LK_SHARED) &&
|
|
!(mp->mnt_kern_flag & MNTK_LOOKUP_SHARED))) {
|
|
lkflags &= ~LK_SHARED;
|
|
lkflags |= LK_EXCLUSIVE;
|
|
}
|
|
lkflags |= LK_NODDLKTREAT;
|
|
return (lkflags);
|
|
}
|
|
|
|
static __inline int
|
|
needs_exclusive_leaf(struct mount *mp, int flags)
|
|
{
|
|
|
|
/*
|
|
* Intermediate nodes can use shared locks, we only need to
|
|
* force an exclusive lock for leaf nodes.
|
|
*/
|
|
if ((flags & (ISLASTCN | LOCKLEAF)) != (ISLASTCN | LOCKLEAF))
|
|
return (0);
|
|
|
|
/* Always use exclusive locks if LOCKSHARED isn't set. */
|
|
if (!(flags & LOCKSHARED))
|
|
return (1);
|
|
|
|
/*
|
|
* For lookups during open(), if the mount point supports
|
|
* extended shared operations, then use a shared lock for the
|
|
* leaf node, otherwise use an exclusive lock.
|
|
*/
|
|
if ((flags & ISOPEN) != 0)
|
|
return (!MNT_EXTENDED_SHARED(mp));
|
|
|
|
/*
|
|
* Lookup requests outside of open() that specify LOCKSHARED
|
|
* only need a shared lock on the leaf vnode.
|
|
*/
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* Various filesystems expect to be able to copy a name component with length
|
|
* bounded by NAME_MAX into a directory entry buffer of size MAXNAMLEN. Make
|
|
* sure that these are the same size.
|
|
*/
|
|
_Static_assert(MAXNAMLEN == NAME_MAX,
|
|
"MAXNAMLEN and NAME_MAX have different values");
|
|
|
|
static int __noinline
|
|
vfs_lookup_degenerate(struct nameidata *ndp, struct vnode *dp, int wantparent)
|
|
{
|
|
struct componentname *cnp;
|
|
struct mount *mp;
|
|
int error;
|
|
|
|
cnp = &ndp->ni_cnd;
|
|
|
|
cnp->cn_flags |= ISLASTCN;
|
|
|
|
mp = atomic_load_ptr(&dp->v_mount);
|
|
if (needs_exclusive_leaf(mp, cnp->cn_flags)) {
|
|
cnp->cn_lkflags &= ~LK_SHARED;
|
|
cnp->cn_lkflags |= LK_EXCLUSIVE;
|
|
}
|
|
|
|
vn_lock(dp,
|
|
compute_cn_lkflags(mp, cnp->cn_lkflags | LK_RETRY,
|
|
cnp->cn_flags));
|
|
|
|
if (dp->v_type != VDIR) {
|
|
error = ENOTDIR;
|
|
goto bad;
|
|
}
|
|
if (cnp->cn_nameiop != LOOKUP) {
|
|
error = EISDIR;
|
|
goto bad;
|
|
}
|
|
if (wantparent) {
|
|
ndp->ni_dvp = dp;
|
|
VREF(dp);
|
|
}
|
|
ndp->ni_vp = dp;
|
|
cnp->cn_namelen = 0;
|
|
|
|
if (cnp->cn_flags & AUDITVNODE1)
|
|
AUDIT_ARG_VNODE1(dp);
|
|
else if (cnp->cn_flags & AUDITVNODE2)
|
|
AUDIT_ARG_VNODE2(dp);
|
|
|
|
if (!(cnp->cn_flags & (LOCKPARENT | LOCKLEAF)))
|
|
VOP_UNLOCK(dp);
|
|
return (0);
|
|
bad:
|
|
VOP_UNLOCK(dp);
|
|
return (error);
|
|
}
|
|
|
|
/*
|
|
* FAILIFEXISTS handling.
|
|
*
|
|
* XXX namei called with LOCKPARENT but not LOCKLEAF has the strange
|
|
* behaviour of leaving the vnode unlocked if the target is the same
|
|
* vnode as the parent.
|
|
*/
|
|
static int __noinline
|
|
vfs_lookup_failifexists(struct nameidata *ndp)
|
|
{
|
|
struct componentname *cnp __diagused;
|
|
|
|
cnp = &ndp->ni_cnd;
|
|
|
|
MPASS((cnp->cn_flags & ISSYMLINK) == 0);
|
|
if (ndp->ni_vp == ndp->ni_dvp)
|
|
vrele(ndp->ni_dvp);
|
|
else
|
|
vput(ndp->ni_dvp);
|
|
vrele(ndp->ni_vp);
|
|
ndp->ni_dvp = NULL;
|
|
ndp->ni_vp = NULL;
|
|
NDFREE_PNBUF(ndp);
|
|
return (EEXIST);
|
|
}
|
|
|
|
/*
|
|
* Search a pathname.
|
|
* This is a very central and rather complicated routine.
|
|
*
|
|
* The pathname is pointed to by ni_ptr and is of length ni_pathlen.
|
|
* The starting directory is taken from ni_startdir. The pathname is
|
|
* descended until done, or a symbolic link is encountered. The variable
|
|
* ni_more is clear if the path is completed; it is set to one if a
|
|
* symbolic link needing interpretation is encountered.
|
|
*
|
|
* The flag argument is LOOKUP, CREATE, RENAME, or DELETE depending on
|
|
* whether the name is to be looked up, created, renamed, or deleted.
|
|
* When CREATE, RENAME, or DELETE is specified, information usable in
|
|
* creating, renaming, or deleting a directory entry may be calculated.
|
|
* If flag has LOCKPARENT or'ed into it, the parent directory is returned
|
|
* locked. If flag has WANTPARENT or'ed into it, the parent directory is
|
|
* returned unlocked. Otherwise the parent directory is not returned. If
|
|
* the target of the pathname exists and LOCKLEAF is or'ed into the flag
|
|
* the target is returned locked, otherwise it is returned unlocked.
|
|
* When creating or renaming and LOCKPARENT is specified, the target may not
|
|
* be ".". When deleting and LOCKPARENT is specified, the target may be ".".
|
|
*
|
|
* Overall outline of lookup:
|
|
*
|
|
* dirloop:
|
|
* identify next component of name at ndp->ni_ptr
|
|
* handle degenerate case where name is null string
|
|
* if .. and crossing mount points and on mounted filesys, find parent
|
|
* call VOP_LOOKUP routine for next component name
|
|
* directory vnode returned in ni_dvp, unlocked unless LOCKPARENT set
|
|
* component vnode returned in ni_vp (if it exists), locked.
|
|
* if result vnode is mounted on and crossing mount points,
|
|
* find mounted on vnode
|
|
* if more components of name, do next level at dirloop
|
|
* return the answer in ni_vp, locked if LOCKLEAF set
|
|
* if LOCKPARENT set, return locked parent in ni_dvp
|
|
* if WANTPARENT set, return unlocked parent in ni_dvp
|
|
*/
|
|
int
|
|
vfs_lookup(struct nameidata *ndp)
|
|
{
|
|
char *cp; /* pointer into pathname argument */
|
|
char *prev_ni_next; /* saved ndp->ni_next */
|
|
char *nulchar; /* location of '\0' in cn_pnbuf */
|
|
char *lastchar; /* location of the last character */
|
|
struct vnode *dp = NULL; /* the directory we are searching */
|
|
struct vnode *tdp; /* saved dp */
|
|
struct mount *mp; /* mount table entry */
|
|
struct prison *pr;
|
|
size_t prev_ni_pathlen; /* saved ndp->ni_pathlen */
|
|
int docache; /* == 0 do not cache last component */
|
|
int wantparent; /* 1 => wantparent or lockparent flag */
|
|
int rdonly; /* lookup read-only flag bit */
|
|
int error = 0;
|
|
int dpunlocked = 0; /* dp has already been unlocked */
|
|
int relookup = 0; /* do not consume the path component */
|
|
struct componentname *cnp = &ndp->ni_cnd;
|
|
int lkflags_save;
|
|
int ni_dvp_unlocked;
|
|
int crosslkflags;
|
|
bool crosslock;
|
|
|
|
/*
|
|
* Setup: break out flag bits into variables.
|
|
*/
|
|
ni_dvp_unlocked = 0;
|
|
wantparent = cnp->cn_flags & (LOCKPARENT | WANTPARENT);
|
|
KASSERT(cnp->cn_nameiop == LOOKUP || wantparent,
|
|
("CREATE, DELETE, RENAME require LOCKPARENT or WANTPARENT."));
|
|
/*
|
|
* When set to zero, docache causes the last component of the
|
|
* pathname to be deleted from the cache and the full lookup
|
|
* of the name to be done (via VOP_CACHEDLOOKUP()). Often
|
|
* filesystems need some pre-computed values that are made
|
|
* during the full lookup, for instance UFS sets dp->i_offset.
|
|
*
|
|
* The docache variable is set to zero when requested by the
|
|
* NOCACHE flag and for all modifying operations except CREATE.
|
|
*/
|
|
docache = (cnp->cn_flags & NOCACHE) ^ NOCACHE;
|
|
if (cnp->cn_nameiop == DELETE ||
|
|
(wantparent && cnp->cn_nameiop != CREATE &&
|
|
cnp->cn_nameiop != LOOKUP))
|
|
docache = 0;
|
|
rdonly = cnp->cn_flags & RDONLY;
|
|
cnp->cn_flags &= ~ISSYMLINK;
|
|
ndp->ni_dvp = NULL;
|
|
|
|
cnp->cn_lkflags = LK_SHARED;
|
|
dp = ndp->ni_startdir;
|
|
ndp->ni_startdir = NULLVP;
|
|
|
|
/*
|
|
* Leading slashes, if any, are supposed to be skipped by the caller.
|
|
*/
|
|
MPASS(cnp->cn_nameptr[0] != '/');
|
|
|
|
/*
|
|
* Check for degenerate name (e.g. / or "") which is a way of talking
|
|
* about a directory, e.g. like "/." or ".".
|
|
*/
|
|
if (__predict_false(cnp->cn_nameptr[0] == '\0')) {
|
|
error = vfs_lookup_degenerate(ndp, dp, wantparent);
|
|
if (error == 0)
|
|
goto success_right_lock;
|
|
goto bad_unlocked;
|
|
}
|
|
|
|
/*
|
|
* Nul-out trailing slashes (e.g., "foo///" -> "foo").
|
|
*
|
|
* This must be done before VOP_LOOKUP() because some fs's don't know
|
|
* about trailing slashes. Remember if there were trailing slashes to
|
|
* handle symlinks, existing non-directories and non-existing files
|
|
* that won't be directories specially later.
|
|
*/
|
|
MPASS(ndp->ni_pathlen >= 2);
|
|
lastchar = &cnp->cn_nameptr[ndp->ni_pathlen - 2];
|
|
if (*lastchar == '/') {
|
|
while (lastchar >= cnp->cn_pnbuf) {
|
|
*lastchar = '\0';
|
|
lastchar--;
|
|
ndp->ni_pathlen--;
|
|
if (*lastchar != '/') {
|
|
break;
|
|
}
|
|
}
|
|
cnp->cn_flags |= TRAILINGSLASH;
|
|
}
|
|
|
|
/*
|
|
* We use shared locks until we hit the parent of the last cn then
|
|
* we adjust based on the requesting flags.
|
|
*/
|
|
vn_lock(dp,
|
|
compute_cn_lkflags(dp->v_mount, cnp->cn_lkflags | LK_RETRY,
|
|
cnp->cn_flags));
|
|
|
|
dirloop:
|
|
/*
|
|
* Search a new directory.
|
|
*
|
|
* The last component of the filename is left accessible via
|
|
* cnp->cn_nameptr. It has to be freed with a call to NDFREE*.
|
|
*
|
|
* Store / as a temporary sentinel so that we only have one character
|
|
* to test for. Pathnames tend to be short so this should not be
|
|
* resulting in cache misses.
|
|
*/
|
|
nulchar = &cnp->cn_nameptr[ndp->ni_pathlen - 1];
|
|
KASSERT(*nulchar == '\0',
|
|
("%s: expected nul at %p; string [%s]\n", __func__, nulchar,
|
|
cnp->cn_pnbuf));
|
|
*nulchar = '/';
|
|
for (cp = cnp->cn_nameptr; *cp != '/'; cp++) {
|
|
KASSERT(*cp != '\0',
|
|
("%s: encountered unexpected nul; string [%s]\n", __func__,
|
|
cnp->cn_nameptr));
|
|
continue;
|
|
}
|
|
*nulchar = '\0';
|
|
cnp->cn_namelen = cp - cnp->cn_nameptr;
|
|
if (__predict_false(cnp->cn_namelen > NAME_MAX)) {
|
|
error = ENAMETOOLONG;
|
|
goto bad;
|
|
}
|
|
#ifdef NAMEI_DIAGNOSTIC
|
|
{ char c = *cp;
|
|
*cp = '\0';
|
|
printf("{%s}: ", cnp->cn_nameptr);
|
|
*cp = c; }
|
|
#endif
|
|
prev_ni_pathlen = ndp->ni_pathlen;
|
|
ndp->ni_pathlen -= cnp->cn_namelen;
|
|
KASSERT(ndp->ni_pathlen <= PATH_MAX,
|
|
("%s: ni_pathlen underflow to %zd\n", __func__, ndp->ni_pathlen));
|
|
prev_ni_next = ndp->ni_next;
|
|
ndp->ni_next = cp;
|
|
|
|
/*
|
|
* Something else should be clearing this.
|
|
*/
|
|
cnp->cn_flags &= ~(ISDOTDOT|ISLASTCN);
|
|
|
|
cnp->cn_flags |= MAKEENTRY;
|
|
if (*cp == '\0' && docache == 0)
|
|
cnp->cn_flags &= ~MAKEENTRY;
|
|
if (cnp->cn_namelen == 2 &&
|
|
cnp->cn_nameptr[1] == '.' && cnp->cn_nameptr[0] == '.')
|
|
cnp->cn_flags |= ISDOTDOT;
|
|
if (*ndp->ni_next == 0) {
|
|
cnp->cn_flags |= ISLASTCN;
|
|
|
|
if (__predict_false(cnp->cn_namelen == 1 && cnp->cn_nameptr[0] == '.' &&
|
|
(cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME))) {
|
|
error = EINVAL;
|
|
goto bad;
|
|
}
|
|
}
|
|
|
|
nameicap_tracker_add(ndp, dp);
|
|
|
|
/*
|
|
* Make sure degenerate names don't get here, their handling was
|
|
* previously found in this spot.
|
|
*/
|
|
MPASS(cnp->cn_nameptr[0] != '\0');
|
|
|
|
/*
|
|
* Handle "..": five special cases.
|
|
* 0. If doing a capability lookup and lookup_cap_dotdot is
|
|
* disabled, return ENOTCAPABLE.
|
|
* 1. Return an error if this is the last component of
|
|
* the name and the operation is DELETE or RENAME.
|
|
* 2. If at root directory (e.g. after chroot)
|
|
* or at absolute root directory
|
|
* then ignore it so can't get out.
|
|
* 3. If this vnode is the root of a mounted
|
|
* filesystem, then replace it with the
|
|
* vnode which was mounted on so we take the
|
|
* .. in the other filesystem.
|
|
* 4. If the vnode is the top directory of
|
|
* the jail or chroot, don't let them out.
|
|
* 5. If doing a capability lookup and lookup_cap_dotdot is
|
|
* enabled, return ENOTCAPABLE if the lookup would escape
|
|
* from the initial file descriptor directory. Checks are
|
|
* done by ensuring that namei() already traversed the
|
|
* result of dotdot lookup.
|
|
*/
|
|
if (cnp->cn_flags & ISDOTDOT) {
|
|
if ((ndp->ni_lcf & (NI_LCF_STRICTRELATIVE | NI_LCF_CAP_DOTDOT))
|
|
== NI_LCF_STRICTRELATIVE) {
|
|
#ifdef KTRACE
|
|
if (KTRPOINT(curthread, KTR_CAPFAIL))
|
|
ktrcapfail(CAPFAIL_LOOKUP, NULL, NULL);
|
|
#endif
|
|
error = ENOTCAPABLE;
|
|
goto bad;
|
|
}
|
|
if ((cnp->cn_flags & ISLASTCN) != 0 &&
|
|
(cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME)) {
|
|
error = EINVAL;
|
|
goto bad;
|
|
}
|
|
for (;;) {
|
|
for (pr = cnp->cn_cred->cr_prison; pr != NULL;
|
|
pr = pr->pr_parent)
|
|
if (dp == pr->pr_root)
|
|
break;
|
|
bool isroot = dp == ndp->ni_rootdir ||
|
|
dp == ndp->ni_topdir || dp == rootvnode ||
|
|
pr != NULL;
|
|
if (isroot && (ndp->ni_lcf &
|
|
NI_LCF_STRICTRELATIVE) != 0) {
|
|
error = ENOTCAPABLE;
|
|
goto capdotdot;
|
|
}
|
|
if (isroot || ((dp->v_vflag & VV_ROOT) != 0 &&
|
|
(cnp->cn_flags & NOCROSSMOUNT) != 0)) {
|
|
ndp->ni_dvp = dp;
|
|
ndp->ni_vp = dp;
|
|
VREF(dp);
|
|
goto nextname;
|
|
}
|
|
if ((dp->v_vflag & VV_ROOT) == 0)
|
|
break;
|
|
if (VN_IS_DOOMED(dp)) { /* forced unmount */
|
|
error = ENOENT;
|
|
goto bad;
|
|
}
|
|
tdp = dp;
|
|
dp = dp->v_mount->mnt_vnodecovered;
|
|
VREF(dp);
|
|
vput(tdp);
|
|
vn_lock(dp,
|
|
compute_cn_lkflags(dp->v_mount, cnp->cn_lkflags |
|
|
LK_RETRY, ISDOTDOT));
|
|
error = nameicap_check_dotdot(ndp, dp);
|
|
if (error != 0) {
|
|
capdotdot:
|
|
#ifdef KTRACE
|
|
if (KTRPOINT(curthread, KTR_CAPFAIL))
|
|
ktrcapfail(CAPFAIL_LOOKUP, NULL, NULL);
|
|
#endif
|
|
goto bad;
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* We now have a segment name to search for, and a directory to search.
|
|
*/
|
|
unionlookup:
|
|
#ifdef MAC
|
|
error = mac_vnode_check_lookup(cnp->cn_cred, dp, cnp);
|
|
if (__predict_false(error))
|
|
goto bad;
|
|
#endif
|
|
ndp->ni_dvp = dp;
|
|
ndp->ni_vp = NULL;
|
|
ASSERT_VOP_LOCKED(dp, "lookup");
|
|
/*
|
|
* If we have a shared lock we may need to upgrade the lock for the
|
|
* last operation.
|
|
*/
|
|
if ((cnp->cn_flags & LOCKPARENT) && (cnp->cn_flags & ISLASTCN) &&
|
|
dp != vp_crossmp && VOP_ISLOCKED(dp) == LK_SHARED)
|
|
vn_lock(dp, LK_UPGRADE|LK_RETRY);
|
|
if (VN_IS_DOOMED(dp)) {
|
|
error = ENOENT;
|
|
goto bad;
|
|
}
|
|
/*
|
|
* If we're looking up the last component and we need an exclusive
|
|
* lock, adjust our lkflags.
|
|
*/
|
|
if (needs_exclusive_leaf(dp->v_mount, cnp->cn_flags))
|
|
cnp->cn_lkflags = LK_EXCLUSIVE;
|
|
#ifdef NAMEI_DIAGNOSTIC
|
|
vn_printf(dp, "lookup in ");
|
|
#endif
|
|
lkflags_save = cnp->cn_lkflags;
|
|
cnp->cn_lkflags = compute_cn_lkflags(dp->v_mount, cnp->cn_lkflags,
|
|
cnp->cn_flags);
|
|
error = VOP_LOOKUP(dp, &ndp->ni_vp, cnp);
|
|
cnp->cn_lkflags = lkflags_save;
|
|
if (error != 0) {
|
|
KASSERT(ndp->ni_vp == NULL, ("leaf should be empty"));
|
|
#ifdef NAMEI_DIAGNOSTIC
|
|
printf("not found\n");
|
|
#endif
|
|
if ((error == ENOENT) &&
|
|
(dp->v_vflag & VV_ROOT) && (dp->v_mount != NULL) &&
|
|
(dp->v_mount->mnt_flag & MNT_UNION)) {
|
|
tdp = dp;
|
|
dp = dp->v_mount->mnt_vnodecovered;
|
|
VREF(dp);
|
|
vput(tdp);
|
|
vn_lock(dp,
|
|
compute_cn_lkflags(dp->v_mount, cnp->cn_lkflags |
|
|
LK_RETRY, cnp->cn_flags));
|
|
nameicap_tracker_add(ndp, dp);
|
|
goto unionlookup;
|
|
}
|
|
|
|
if (error == ERELOOKUP) {
|
|
vref(dp);
|
|
ndp->ni_vp = dp;
|
|
error = 0;
|
|
relookup = 1;
|
|
goto good;
|
|
}
|
|
|
|
if (error != EJUSTRETURN)
|
|
goto bad;
|
|
/*
|
|
* At this point, we know we're at the end of the
|
|
* pathname. If creating / renaming, we can consider
|
|
* allowing the file or directory to be created / renamed,
|
|
* provided we're not on a read-only filesystem.
|
|
*/
|
|
if (rdonly) {
|
|
error = EROFS;
|
|
goto bad;
|
|
}
|
|
/* trailing slash only allowed for directories */
|
|
if ((cnp->cn_flags & TRAILINGSLASH) &&
|
|
!(cnp->cn_flags & WILLBEDIR)) {
|
|
error = ENOENT;
|
|
goto bad;
|
|
}
|
|
if ((cnp->cn_flags & LOCKPARENT) == 0)
|
|
VOP_UNLOCK(dp);
|
|
/*
|
|
* We return with ni_vp NULL to indicate that the entry
|
|
* doesn't currently exist, leaving a pointer to the
|
|
* (possibly locked) directory vnode in ndp->ni_dvp.
|
|
*/
|
|
goto success;
|
|
}
|
|
|
|
good:
|
|
#ifdef NAMEI_DIAGNOSTIC
|
|
printf("found\n");
|
|
#endif
|
|
dp = ndp->ni_vp;
|
|
|
|
/*
|
|
* Check for symbolic link
|
|
*/
|
|
if ((dp->v_type == VLNK) &&
|
|
((cnp->cn_flags & FOLLOW) || (cnp->cn_flags & TRAILINGSLASH) ||
|
|
*ndp->ni_next == '/')) {
|
|
cnp->cn_flags |= ISSYMLINK;
|
|
if (VN_IS_DOOMED(dp)) {
|
|
/*
|
|
* We can't know whether the directory was mounted with
|
|
* NOSYMFOLLOW, so we can't follow safely.
|
|
*/
|
|
error = ENOENT;
|
|
goto bad2;
|
|
}
|
|
if (dp->v_mount->mnt_flag & MNT_NOSYMFOLLOW) {
|
|
error = EACCES;
|
|
goto bad2;
|
|
}
|
|
/*
|
|
* Symlink code always expects an unlocked dvp.
|
|
*/
|
|
if (ndp->ni_dvp != ndp->ni_vp) {
|
|
VOP_UNLOCK(ndp->ni_dvp);
|
|
ni_dvp_unlocked = 1;
|
|
}
|
|
goto success;
|
|
} else if ((vn_irflag_read(dp) & VIRF_MOUNTPOINT) != 0) {
|
|
if ((cnp->cn_flags & NOCROSSMOUNT) != 0)
|
|
goto nextname;
|
|
} else
|
|
goto nextname;
|
|
|
|
/*
|
|
* Check to see if the vnode has been mounted on;
|
|
* if so find the root of the mounted filesystem.
|
|
*/
|
|
do {
|
|
mp = dp->v_mountedhere;
|
|
KASSERT(mp != NULL,
|
|
("%s: NULL mountpoint for VIRF_MOUNTPOINT vnode", __func__));
|
|
crosslock = (dp->v_vflag & VV_CROSSLOCK) != 0;
|
|
crosslkflags = compute_cn_lkflags(mp, cnp->cn_lkflags,
|
|
cnp->cn_flags);
|
|
if (__predict_false(crosslock)) {
|
|
/*
|
|
* We are going to be holding the vnode lock, which
|
|
* in this case is shared by the root vnode of the
|
|
* filesystem mounted at mp, across the call to
|
|
* VFS_ROOT(). Make the situation clear to the
|
|
* filesystem by passing LK_CANRECURSE if the
|
|
* lock is held exclusive, or by clearinng
|
|
* LK_NODDLKTREAT to allow recursion on the shared
|
|
* lock in the presence of an exclusive waiter.
|
|
*/
|
|
if (VOP_ISLOCKED(dp) == LK_EXCLUSIVE) {
|
|
crosslkflags &= ~LK_SHARED;
|
|
crosslkflags |= LK_EXCLUSIVE | LK_CANRECURSE;
|
|
} else if ((crosslkflags & LK_EXCLUSIVE) != 0) {
|
|
vn_lock(dp, LK_UPGRADE | LK_RETRY);
|
|
if (VN_IS_DOOMED(dp)) {
|
|
error = ENOENT;
|
|
goto bad2;
|
|
}
|
|
if (dp->v_mountedhere != mp) {
|
|
continue;
|
|
}
|
|
} else
|
|
crosslkflags &= ~LK_NODDLKTREAT;
|
|
}
|
|
if (vfs_busy(mp, 0) != 0)
|
|
continue;
|
|
if (__predict_true(!crosslock))
|
|
vput(dp);
|
|
if (dp != ndp->ni_dvp)
|
|
vput(ndp->ni_dvp);
|
|
else
|
|
vrele(ndp->ni_dvp);
|
|
vrefact(vp_crossmp);
|
|
ndp->ni_dvp = vp_crossmp;
|
|
error = VFS_ROOT(mp, crosslkflags, &tdp);
|
|
vfs_unbusy(mp);
|
|
if (__predict_false(crosslock))
|
|
vput(dp);
|
|
if (vn_lock(vp_crossmp, LK_SHARED | LK_NOWAIT))
|
|
panic("vp_crossmp exclusively locked or reclaimed");
|
|
if (error != 0) {
|
|
dpunlocked = 1;
|
|
goto bad2;
|
|
}
|
|
ndp->ni_vp = dp = tdp;
|
|
} while ((vn_irflag_read(dp) & VIRF_MOUNTPOINT) != 0);
|
|
|
|
nextname:
|
|
/*
|
|
* Not a symbolic link that we will follow. Continue with the
|
|
* next component if there is any; otherwise, we're done.
|
|
*/
|
|
KASSERT((cnp->cn_flags & ISLASTCN) || *ndp->ni_next == '/',
|
|
("lookup: invalid path state."));
|
|
if (relookup) {
|
|
relookup = 0;
|
|
ndp->ni_pathlen = prev_ni_pathlen;
|
|
ndp->ni_next = prev_ni_next;
|
|
if (ndp->ni_dvp != dp)
|
|
vput(ndp->ni_dvp);
|
|
else
|
|
vrele(ndp->ni_dvp);
|
|
goto dirloop;
|
|
}
|
|
if (cnp->cn_flags & ISDOTDOT) {
|
|
error = nameicap_check_dotdot(ndp, ndp->ni_vp);
|
|
if (error != 0) {
|
|
#ifdef KTRACE
|
|
if (KTRPOINT(curthread, KTR_CAPFAIL))
|
|
ktrcapfail(CAPFAIL_LOOKUP, NULL, NULL);
|
|
#endif
|
|
goto bad2;
|
|
}
|
|
}
|
|
if (*ndp->ni_next == '/') {
|
|
cnp->cn_nameptr = ndp->ni_next;
|
|
while (*cnp->cn_nameptr == '/') {
|
|
cnp->cn_nameptr++;
|
|
ndp->ni_pathlen--;
|
|
}
|
|
if (ndp->ni_dvp != dp)
|
|
vput(ndp->ni_dvp);
|
|
else
|
|
vrele(ndp->ni_dvp);
|
|
goto dirloop;
|
|
}
|
|
/*
|
|
* If we're processing a path with a trailing slash,
|
|
* check that the end result is a directory.
|
|
*/
|
|
if ((cnp->cn_flags & TRAILINGSLASH) && dp->v_type != VDIR) {
|
|
error = ENOTDIR;
|
|
goto bad2;
|
|
}
|
|
/*
|
|
* Disallow directory write attempts on read-only filesystems.
|
|
*/
|
|
if (rdonly &&
|
|
(cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME)) {
|
|
error = EROFS;
|
|
goto bad2;
|
|
}
|
|
if (!wantparent) {
|
|
ni_dvp_unlocked = 2;
|
|
if (ndp->ni_dvp != dp)
|
|
vput(ndp->ni_dvp);
|
|
else
|
|
vrele(ndp->ni_dvp);
|
|
} else if ((cnp->cn_flags & LOCKPARENT) == 0 && ndp->ni_dvp != dp) {
|
|
VOP_UNLOCK(ndp->ni_dvp);
|
|
ni_dvp_unlocked = 1;
|
|
}
|
|
|
|
if (cnp->cn_flags & AUDITVNODE1)
|
|
AUDIT_ARG_VNODE1(dp);
|
|
else if (cnp->cn_flags & AUDITVNODE2)
|
|
AUDIT_ARG_VNODE2(dp);
|
|
|
|
if ((cnp->cn_flags & LOCKLEAF) == 0)
|
|
VOP_UNLOCK(dp);
|
|
success:
|
|
/*
|
|
* FIXME: for lookups which only cross a mount point to fetch the
|
|
* root vnode, ni_dvp will be set to vp_crossmp. This can be a problem
|
|
* if either WANTPARENT or LOCKPARENT is set.
|
|
*/
|
|
/*
|
|
* Because of shared lookup we may have the vnode shared locked, but
|
|
* the caller may want it to be exclusively locked.
|
|
*/
|
|
if (needs_exclusive_leaf(dp->v_mount, cnp->cn_flags) &&
|
|
VOP_ISLOCKED(dp) != LK_EXCLUSIVE) {
|
|
vn_lock(dp, LK_UPGRADE | LK_RETRY);
|
|
if (VN_IS_DOOMED(dp)) {
|
|
error = ENOENT;
|
|
goto bad2;
|
|
}
|
|
}
|
|
success_right_lock:
|
|
if (ndp->ni_vp != NULL) {
|
|
if ((cnp->cn_flags & ISDOTDOT) == 0)
|
|
nameicap_tracker_add(ndp, ndp->ni_vp);
|
|
if ((cnp->cn_flags & (FAILIFEXISTS | ISSYMLINK)) == FAILIFEXISTS)
|
|
return (vfs_lookup_failifexists(ndp));
|
|
}
|
|
return (0);
|
|
|
|
bad2:
|
|
if (ni_dvp_unlocked != 2) {
|
|
if (dp != ndp->ni_dvp && !ni_dvp_unlocked)
|
|
vput(ndp->ni_dvp);
|
|
else
|
|
vrele(ndp->ni_dvp);
|
|
}
|
|
bad:
|
|
if (!dpunlocked)
|
|
vput(dp);
|
|
bad_unlocked:
|
|
ndp->ni_vp = NULL;
|
|
return (error);
|
|
}
|
|
|
|
/*
|
|
* relookup - lookup a path name component
|
|
* Used by lookup to re-acquire things.
|
|
*/
|
|
int
|
|
vfs_relookup(struct vnode *dvp, struct vnode **vpp, struct componentname *cnp,
|
|
bool refstart)
|
|
{
|
|
struct vnode *dp = NULL; /* the directory we are searching */
|
|
int rdonly; /* lookup read-only flag bit */
|
|
int error = 0;
|
|
|
|
KASSERT(cnp->cn_flags & ISLASTCN,
|
|
("relookup: Not given last component."));
|
|
/*
|
|
* Setup: break out flag bits into variables.
|
|
*/
|
|
KASSERT((cnp->cn_flags & (LOCKPARENT | WANTPARENT)) != 0,
|
|
("relookup: parent not wanted"));
|
|
rdonly = cnp->cn_flags & RDONLY;
|
|
cnp->cn_flags &= ~ISSYMLINK;
|
|
dp = dvp;
|
|
cnp->cn_lkflags = LK_EXCLUSIVE;
|
|
vn_lock(dp, LK_EXCLUSIVE | LK_RETRY);
|
|
|
|
/*
|
|
* Search a new directory.
|
|
*
|
|
* See a comment in vfs_lookup for cnp->cn_nameptr.
|
|
*/
|
|
#ifdef NAMEI_DIAGNOSTIC
|
|
printf("{%s}: ", cnp->cn_nameptr);
|
|
#endif
|
|
|
|
/*
|
|
* Check for "" which represents the root directory after slash
|
|
* removal.
|
|
*/
|
|
if (cnp->cn_nameptr[0] == '\0') {
|
|
/*
|
|
* Support only LOOKUP for "/" because lookup()
|
|
* can't succeed for CREATE, DELETE and RENAME.
|
|
*/
|
|
KASSERT(cnp->cn_nameiop == LOOKUP, ("nameiop must be LOOKUP"));
|
|
KASSERT(dp->v_type == VDIR, ("dp is not a directory"));
|
|
|
|
if (!(cnp->cn_flags & LOCKLEAF))
|
|
VOP_UNLOCK(dp);
|
|
*vpp = dp;
|
|
/* XXX This should probably move to the top of function. */
|
|
if (refstart)
|
|
panic("lookup: SAVESTART");
|
|
return (0);
|
|
}
|
|
|
|
if (cnp->cn_flags & ISDOTDOT)
|
|
panic ("relookup: lookup on dot-dot");
|
|
|
|
/*
|
|
* We now have a segment name to search for, and a directory to search.
|
|
*/
|
|
#ifdef NAMEI_DIAGNOSTIC
|
|
vn_printf(dp, "search in ");
|
|
#endif
|
|
if ((error = VOP_LOOKUP(dp, vpp, cnp)) != 0) {
|
|
KASSERT(*vpp == NULL, ("leaf should be empty"));
|
|
if (error != EJUSTRETURN)
|
|
goto bad;
|
|
/*
|
|
* If creating and at end of pathname, then can consider
|
|
* allowing file to be created.
|
|
*/
|
|
if (rdonly) {
|
|
error = EROFS;
|
|
goto bad;
|
|
}
|
|
/* ASSERT(dvp == ndp->ni_startdir) */
|
|
if (refstart)
|
|
VREF(dvp);
|
|
if ((cnp->cn_flags & LOCKPARENT) == 0)
|
|
VOP_UNLOCK(dp);
|
|
/*
|
|
* We return with ni_vp NULL to indicate that the entry
|
|
* doesn't currently exist, leaving a pointer to the
|
|
* (possibly locked) directory vnode in ndp->ni_dvp.
|
|
*/
|
|
return (0);
|
|
}
|
|
|
|
dp = *vpp;
|
|
|
|
/*
|
|
* Disallow directory write attempts on read-only filesystems.
|
|
*/
|
|
if (rdonly &&
|
|
(cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME)) {
|
|
if (dvp == dp)
|
|
vrele(dvp);
|
|
else
|
|
vput(dvp);
|
|
error = EROFS;
|
|
goto bad;
|
|
}
|
|
/*
|
|
* Set the parent lock/ref state to the requested state.
|
|
*/
|
|
if ((cnp->cn_flags & LOCKPARENT) == 0 && dvp != dp)
|
|
VOP_UNLOCK(dvp);
|
|
/*
|
|
* Check for symbolic link
|
|
*/
|
|
KASSERT(dp->v_type != VLNK || !(cnp->cn_flags & FOLLOW),
|
|
("relookup: symlink found.\n"));
|
|
|
|
/* ASSERT(dvp == ndp->ni_startdir) */
|
|
if (refstart)
|
|
VREF(dvp);
|
|
|
|
if ((cnp->cn_flags & LOCKLEAF) == 0)
|
|
VOP_UNLOCK(dp);
|
|
return (0);
|
|
bad:
|
|
vput(dp);
|
|
*vpp = NULL;
|
|
return (error);
|
|
}
|
|
|
|
#ifdef INVARIANTS
|
|
/*
|
|
* Validate the final state of ndp after the lookup.
|
|
*/
|
|
static void
|
|
NDVALIDATE_impl(struct nameidata *ndp, int line)
|
|
{
|
|
struct componentname *cnp;
|
|
|
|
cnp = &ndp->ni_cnd;
|
|
if (cnp->cn_pnbuf == NULL)
|
|
panic("%s: got no buf! called from %d", __func__, line);
|
|
}
|
|
|
|
#endif
|
|
|
|
/*
|
|
* Determine if there is a suitable alternate filename under the specified
|
|
* prefix for the specified path. If the create flag is set, then the
|
|
* alternate prefix will be used so long as the parent directory exists.
|
|
* This is used by the various compatibility ABIs so that Linux binaries prefer
|
|
* files under /compat/linux for example. The chosen path (whether under
|
|
* the prefix or under /) is returned in a kernel malloc'd buffer pointed
|
|
* to by pathbuf. The caller is responsible for free'ing the buffer from
|
|
* the M_TEMP bucket if one is returned.
|
|
*/
|
|
int
|
|
kern_alternate_path(const char *prefix, const char *path, enum uio_seg pathseg,
|
|
char **pathbuf, int create, int dirfd)
|
|
{
|
|
struct nameidata nd, ndroot;
|
|
char *ptr, *buf, *cp;
|
|
size_t len, sz;
|
|
int error;
|
|
|
|
buf = (char *) malloc(MAXPATHLEN, M_TEMP, M_WAITOK);
|
|
*pathbuf = buf;
|
|
|
|
/* Copy the prefix into the new pathname as a starting point. */
|
|
len = strlcpy(buf, prefix, MAXPATHLEN);
|
|
if (len >= MAXPATHLEN) {
|
|
*pathbuf = NULL;
|
|
free(buf, M_TEMP);
|
|
return (EINVAL);
|
|
}
|
|
sz = MAXPATHLEN - len;
|
|
ptr = buf + len;
|
|
|
|
/* Append the filename to the prefix. */
|
|
if (pathseg == UIO_SYSSPACE)
|
|
error = copystr(path, ptr, sz, &len);
|
|
else
|
|
error = copyinstr(path, ptr, sz, &len);
|
|
|
|
if (error) {
|
|
*pathbuf = NULL;
|
|
free(buf, M_TEMP);
|
|
return (error);
|
|
}
|
|
|
|
/* Only use a prefix with absolute pathnames. */
|
|
if (*ptr != '/') {
|
|
error = EINVAL;
|
|
goto keeporig;
|
|
}
|
|
|
|
if (dirfd != AT_FDCWD) {
|
|
/*
|
|
* We want the original because the "prefix" is
|
|
* included in the already opened dirfd.
|
|
*/
|
|
bcopy(ptr, buf, len);
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* We know that there is a / somewhere in this pathname.
|
|
* Search backwards for it, to find the file's parent dir
|
|
* to see if it exists in the alternate tree. If it does,
|
|
* and we want to create a file (cflag is set). We don't
|
|
* need to worry about the root comparison in this case.
|
|
*/
|
|
|
|
if (create) {
|
|
for (cp = &ptr[len] - 1; *cp != '/'; cp--);
|
|
*cp = '\0';
|
|
|
|
NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_SYSSPACE, buf);
|
|
error = namei(&nd);
|
|
*cp = '/';
|
|
if (error != 0)
|
|
goto keeporig;
|
|
} else {
|
|
NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_SYSSPACE, buf);
|
|
|
|
error = namei(&nd);
|
|
if (error != 0)
|
|
goto keeporig;
|
|
|
|
/*
|
|
* We now compare the vnode of the prefix to the one
|
|
* vnode asked. If they resolve to be the same, then we
|
|
* ignore the match so that the real root gets used.
|
|
* This avoids the problem of traversing "../.." to find the
|
|
* root directory and never finding it, because "/" resolves
|
|
* to the emulation root directory. This is expensive :-(
|
|
*/
|
|
NDINIT(&ndroot, LOOKUP, FOLLOW, UIO_SYSSPACE, prefix);
|
|
|
|
/* We shouldn't ever get an error from this namei(). */
|
|
error = namei(&ndroot);
|
|
if (error == 0) {
|
|
if (nd.ni_vp == ndroot.ni_vp)
|
|
error = ENOENT;
|
|
|
|
NDFREE_PNBUF(&ndroot);
|
|
vrele(ndroot.ni_vp);
|
|
}
|
|
}
|
|
|
|
NDFREE_PNBUF(&nd);
|
|
vrele(nd.ni_vp);
|
|
|
|
keeporig:
|
|
/* If there was an error, use the original path name. */
|
|
if (error)
|
|
bcopy(ptr, buf, len);
|
|
return (error);
|
|
}
|