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freebsd/sys/fs/unionfs/union_subr.c
Pedro F. Giffuni 51369649b0 sys: further adoption of SPDX licensing ID tags. 
Mainly focus on files that use BSD 3-Clause license.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.

Special thanks to Wind River for providing access to "The Duke of
Highlander" tool: an older (2014) run over FreeBSD tree was useful as a
starting point.
2017-11-20 19:43:44 +00:00

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/*-
* SPDX-License-Identifier: BSD-3-Clause
*
* Copyright (c) 1994 Jan-Simon Pendry
* Copyright (c) 1994
* The Regents of the University of California. All rights reserved.
* Copyright (c) 2005, 2006, 2012 Masanori Ozawa <ozawa@ongs.co.jp>, ONGS Inc.
* Copyright (c) 2006, 2012 Daichi Goto <daichi@freebsd.org>
*
* This code is derived from software contributed to Berkeley by
* Jan-Simon Pendry.
*
* 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.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
*
* @(#)union_subr.c 8.20 (Berkeley) 5/20/95
* $FreeBSD$
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/malloc.h>
#include <sys/mount.h>
#include <sys/namei.h>
#include <sys/proc.h>
#include <sys/vnode.h>
#include <sys/dirent.h>
#include <sys/fcntl.h>
#include <sys/filedesc.h>
#include <sys/stat.h>
#include <sys/resourcevar.h>
#include <security/mac/mac_framework.h>
#include <vm/uma.h>
#include <fs/unionfs/union.h>
#define NUNIONFSNODECACHE 16
static MALLOC_DEFINE(M_UNIONFSHASH, "UNIONFS hash", "UNIONFS hash table");
MALLOC_DEFINE(M_UNIONFSNODE, "UNIONFS node", "UNIONFS vnode private part");
MALLOC_DEFINE(M_UNIONFSPATH, "UNIONFS path", "UNIONFS path private part");
/*
* Initialize
*/
int
unionfs_init(struct vfsconf *vfsp)
{
UNIONFSDEBUG("unionfs_init\n"); /* printed during system boot */
return (0);
}
/*
* Uninitialize
*/
int
unionfs_uninit(struct vfsconf *vfsp)
{
return (0);
}
static struct unionfs_node_hashhead *
unionfs_get_hashhead(struct vnode *dvp, char *path)
{
int count;
char hash;
struct unionfs_node *unp;
hash = 0;
unp = VTOUNIONFS(dvp);
if (path != NULL) {
for (count = 0; path[count]; count++)
hash += path[count];
}
return (&(unp->un_hashtbl[hash & (unp->un_hashmask)]));
}
/*
* Get the cached vnode.
*/
static struct vnode *
unionfs_get_cached_vnode(struct vnode *uvp, struct vnode *lvp,
struct vnode *dvp, char *path)
{
struct unionfs_node_hashhead *hd;
struct unionfs_node *unp;
struct vnode *vp;
KASSERT((uvp == NULLVP || uvp->v_type == VDIR),
("unionfs_get_cached_vnode: v_type != VDIR"));
KASSERT((lvp == NULLVP || lvp->v_type == VDIR),
("unionfs_get_cached_vnode: v_type != VDIR"));
VI_LOCK(dvp);
hd = unionfs_get_hashhead(dvp, path);
LIST_FOREACH(unp, hd, un_hash) {
if (!strcmp(unp->un_path, path)) {
vp = UNIONFSTOV(unp);
VI_LOCK_FLAGS(vp, MTX_DUPOK);
VI_UNLOCK(dvp);
vp->v_iflag &= ~VI_OWEINACT;
if ((vp->v_iflag & (VI_DOOMED | VI_DOINGINACT)) != 0) {
VI_UNLOCK(vp);
vp = NULLVP;
} else
VI_UNLOCK(vp);
return (vp);
}
}
VI_UNLOCK(dvp);
return (NULLVP);
}
/*
* Add the new vnode into cache.
*/
static struct vnode *
unionfs_ins_cached_vnode(struct unionfs_node *uncp,
struct vnode *dvp, char *path)
{
struct unionfs_node_hashhead *hd;
struct unionfs_node *unp;
struct vnode *vp;
KASSERT((uncp->un_uppervp==NULLVP || uncp->un_uppervp->v_type==VDIR),
("unionfs_ins_cached_vnode: v_type != VDIR"));
KASSERT((uncp->un_lowervp==NULLVP || uncp->un_lowervp->v_type==VDIR),
("unionfs_ins_cached_vnode: v_type != VDIR"));
VI_LOCK(dvp);
hd = unionfs_get_hashhead(dvp, path);
LIST_FOREACH(unp, hd, un_hash) {
if (!strcmp(unp->un_path, path)) {
vp = UNIONFSTOV(unp);
VI_LOCK_FLAGS(vp, MTX_DUPOK);
vp->v_iflag &= ~VI_OWEINACT;
if ((vp->v_iflag & (VI_DOOMED | VI_DOINGINACT)) != 0) {
LIST_INSERT_HEAD(hd, uncp, un_hash);
VI_UNLOCK(vp);
vp = NULLVP;
} else
VI_UNLOCK(vp);
VI_UNLOCK(dvp);
return (vp);
}
}
LIST_INSERT_HEAD(hd, uncp, un_hash);
VI_UNLOCK(dvp);
return (NULLVP);
}
/*
* Remove the vnode.
*/
static void
unionfs_rem_cached_vnode(struct unionfs_node *unp, struct vnode *dvp)
{
KASSERT((unp != NULL), ("unionfs_rem_cached_vnode: null node"));
KASSERT((dvp != NULLVP),
("unionfs_rem_cached_vnode: null parent vnode"));
KASSERT((unp->un_hash.le_prev != NULL),
("unionfs_rem_cached_vnode: null hash"));
VI_LOCK(dvp);
LIST_REMOVE(unp, un_hash);
unp->un_hash.le_next = NULL;
unp->un_hash.le_prev = NULL;
VI_UNLOCK(dvp);
}
/*
* Make a new or get existing unionfs node.
*
* uppervp and lowervp should be unlocked. Because if new unionfs vnode is
* locked, uppervp or lowervp is locked too. In order to prevent dead lock,
* you should not lock plurality simultaneously.
*/
int
unionfs_nodeget(struct mount *mp, struct vnode *uppervp,
struct vnode *lowervp, struct vnode *dvp,
struct vnode **vpp, struct componentname *cnp,
struct thread *td)
{
struct unionfs_mount *ump;
struct unionfs_node *unp;
struct vnode *vp;
int error;
int lkflags;
enum vtype vt;
char *path;
ump = MOUNTTOUNIONFSMOUNT(mp);
lkflags = (cnp ? cnp->cn_lkflags : 0);
path = (cnp ? cnp->cn_nameptr : NULL);
*vpp = NULLVP;
if (uppervp == NULLVP && lowervp == NULLVP)
panic("unionfs_nodeget: upper and lower is null");
vt = (uppervp != NULLVP ? uppervp->v_type : lowervp->v_type);
/* If it has no ISLASTCN flag, path check is skipped. */
if (cnp && !(cnp->cn_flags & ISLASTCN))
path = NULL;
/* check the cache */
if (path != NULL && dvp != NULLVP && vt == VDIR) {
vp = unionfs_get_cached_vnode(uppervp, lowervp, dvp, path);
if (vp != NULLVP) {
vref(vp);
*vpp = vp;
goto unionfs_nodeget_out;
}
}
if ((uppervp == NULLVP || ump->um_uppervp != uppervp) ||
(lowervp == NULLVP || ump->um_lowervp != lowervp)) {
/* dvp will be NULLVP only in case of root vnode. */
if (dvp == NULLVP)
return (EINVAL);
}
unp = malloc(sizeof(struct unionfs_node),
M_UNIONFSNODE, M_WAITOK | M_ZERO);
error = getnewvnode("unionfs", mp, &unionfs_vnodeops, &vp);
if (error != 0) {
free(unp, M_UNIONFSNODE);
return (error);
}
error = insmntque(vp, mp); /* XXX: Too early for mpsafe fs */
if (error != 0) {
free(unp, M_UNIONFSNODE);
return (error);
}
if (dvp != NULLVP)
vref(dvp);
if (uppervp != NULLVP)
vref(uppervp);
if (lowervp != NULLVP)
vref(lowervp);
if (vt == VDIR)
unp->un_hashtbl = hashinit(NUNIONFSNODECACHE, M_UNIONFSHASH,
&(unp->un_hashmask));
unp->un_vnode = vp;
unp->un_uppervp = uppervp;
unp->un_lowervp = lowervp;
unp->un_dvp = dvp;
if (uppervp != NULLVP)
vp->v_vnlock = uppervp->v_vnlock;
else
vp->v_vnlock = lowervp->v_vnlock;
if (path != NULL) {
unp->un_path = (char *)
malloc(cnp->cn_namelen +1, M_UNIONFSPATH, M_WAITOK|M_ZERO);
bcopy(cnp->cn_nameptr, unp->un_path, cnp->cn_namelen);
unp->un_path[cnp->cn_namelen] = '\0';
}
vp->v_type = vt;
vp->v_data = unp;
if ((uppervp != NULLVP && ump->um_uppervp == uppervp) &&
(lowervp != NULLVP && ump->um_lowervp == lowervp))
vp->v_vflag |= VV_ROOT;
if (path != NULL && dvp != NULLVP && vt == VDIR)
*vpp = unionfs_ins_cached_vnode(unp, dvp, path);
if ((*vpp) != NULLVP) {
if (dvp != NULLVP)
vrele(dvp);
if (uppervp != NULLVP)
vrele(uppervp);
if (lowervp != NULLVP)
vrele(lowervp);
unp->un_uppervp = NULLVP;
unp->un_lowervp = NULLVP;
unp->un_dvp = NULLVP;
vrele(vp);
vp = *vpp;
vref(vp);
} else
*vpp = vp;
unionfs_nodeget_out:
if (lkflags & LK_TYPE_MASK)
vn_lock(vp, lkflags | LK_RETRY);
return (0);
}
/*
* Clean up the unionfs node.
*/
void
unionfs_noderem(struct vnode *vp, struct thread *td)
{
int count;
struct unionfs_node *unp, *unp_t1, *unp_t2;
struct unionfs_node_hashhead *hd;
struct unionfs_node_status *unsp, *unsp_tmp;
struct vnode *lvp;
struct vnode *uvp;
struct vnode *dvp;
/*
* Use the interlock to protect the clearing of v_data to
* prevent faults in unionfs_lock().
*/
VI_LOCK(vp);
unp = VTOUNIONFS(vp);
lvp = unp->un_lowervp;
uvp = unp->un_uppervp;
dvp = unp->un_dvp;
unp->un_lowervp = unp->un_uppervp = NULLVP;
vp->v_vnlock = &(vp->v_lock);
vp->v_data = NULL;
vp->v_object = NULL;
VI_UNLOCK(vp);
if (lvp != NULLVP)
VOP_UNLOCK(lvp, LK_RELEASE);
if (uvp != NULLVP)
VOP_UNLOCK(uvp, LK_RELEASE);
if (dvp != NULLVP && unp->un_hash.le_prev != NULL)
unionfs_rem_cached_vnode(unp, dvp);
if (lockmgr(vp->v_vnlock, LK_EXCLUSIVE, VI_MTX(vp)) != 0)
panic("the lock for deletion is unacquirable.");
if (lvp != NULLVP)
vrele(lvp);
if (uvp != NULLVP)
vrele(uvp);
if (dvp != NULLVP) {
vrele(dvp);
unp->un_dvp = NULLVP;
}
if (unp->un_path != NULL) {
free(unp->un_path, M_UNIONFSPATH);
unp->un_path = NULL;
}
if (unp->un_hashtbl != NULL) {
for (count = 0; count <= unp->un_hashmask; count++) {
hd = unp->un_hashtbl + count;
LIST_FOREACH_SAFE(unp_t1, hd, un_hash, unp_t2) {
LIST_REMOVE(unp_t1, un_hash);
unp_t1->un_hash.le_next = NULL;
unp_t1->un_hash.le_prev = NULL;
}
}
hashdestroy(unp->un_hashtbl, M_UNIONFSHASH, unp->un_hashmask);
}
LIST_FOREACH_SAFE(unsp, &(unp->un_unshead), uns_list, unsp_tmp) {
LIST_REMOVE(unsp, uns_list);
free(unsp, M_TEMP);
}
free(unp, M_UNIONFSNODE);
}
/*
* Get the unionfs node status.
* You need exclusive lock this vnode.
*/
void
unionfs_get_node_status(struct unionfs_node *unp, struct thread *td,
struct unionfs_node_status **unspp)
{
struct unionfs_node_status *unsp;
pid_t pid = td->td_proc->p_pid;
KASSERT(NULL != unspp, ("null pointer"));
ASSERT_VOP_ELOCKED(UNIONFSTOV(unp), "unionfs_get_node_status");
LIST_FOREACH(unsp, &(unp->un_unshead), uns_list) {
if (unsp->uns_pid == pid) {
*unspp = unsp;
return;
}
}
/* create a new unionfs node status */
unsp = malloc(sizeof(struct unionfs_node_status),
M_TEMP, M_WAITOK | M_ZERO);
unsp->uns_pid = pid;
LIST_INSERT_HEAD(&(unp->un_unshead), unsp, uns_list);
*unspp = unsp;
}
/*
* Remove the unionfs node status, if you can.
* You need exclusive lock this vnode.
*/
void
unionfs_tryrem_node_status(struct unionfs_node *unp,
struct unionfs_node_status *unsp)
{
KASSERT(NULL != unsp, ("null pointer"));
ASSERT_VOP_ELOCKED(UNIONFSTOV(unp), "unionfs_get_node_status");
if (0 < unsp->uns_lower_opencnt || 0 < unsp->uns_upper_opencnt)
return;
LIST_REMOVE(unsp, uns_list);
free(unsp, M_TEMP);
}
/*
* Create upper node attr.
*/
void
unionfs_create_uppervattr_core(struct unionfs_mount *ump,
struct vattr *lva,
struct vattr *uva,
struct thread *td)
{
VATTR_NULL(uva);
uva->va_type = lva->va_type;
uva->va_atime = lva->va_atime;
uva->va_mtime = lva->va_mtime;
uva->va_ctime = lva->va_ctime;
switch (ump->um_copymode) {
case UNIONFS_TRANSPARENT:
uva->va_mode = lva->va_mode;
uva->va_uid = lva->va_uid;
uva->va_gid = lva->va_gid;
break;
case UNIONFS_MASQUERADE:
if (ump->um_uid == lva->va_uid) {
uva->va_mode = lva->va_mode & 077077;
uva->va_mode |= (lva->va_type == VDIR ? ump->um_udir : ump->um_ufile) & 0700;
uva->va_uid = lva->va_uid;
uva->va_gid = lva->va_gid;
} else {
uva->va_mode = (lva->va_type == VDIR ? ump->um_udir : ump->um_ufile);
uva->va_uid = ump->um_uid;
uva->va_gid = ump->um_gid;
}
break;
default: /* UNIONFS_TRADITIONAL */
uva->va_mode = 0777 & ~td->td_proc->p_fd->fd_cmask;
uva->va_uid = ump->um_uid;
uva->va_gid = ump->um_gid;
break;
}
}
/*
* Create upper node attr.
*/
int
unionfs_create_uppervattr(struct unionfs_mount *ump,
struct vnode *lvp,
struct vattr *uva,
struct ucred *cred,
struct thread *td)
{
int error;
struct vattr lva;
if ((error = VOP_GETATTR(lvp, &lva, cred)))
return (error);
unionfs_create_uppervattr_core(ump, &lva, uva, td);
return (error);
}
/*
* relookup
*
* dvp should be locked on entry and will be locked on return.
*
* If an error is returned, *vpp will be invalid, otherwise it will hold a
* locked, referenced vnode. If *vpp == dvp then remember that only one
* LK_EXCLUSIVE lock is held.
*/
int
unionfs_relookup(struct vnode *dvp, struct vnode **vpp,
struct componentname *cnp, struct componentname *cn,
struct thread *td, char *path, int pathlen, u_long nameiop)
{
int error;
cn->cn_namelen = pathlen;
cn->cn_pnbuf = uma_zalloc(namei_zone, M_WAITOK);
bcopy(path, cn->cn_pnbuf, pathlen);
cn->cn_pnbuf[pathlen] = '\0';
cn->cn_nameiop = nameiop;
cn->cn_flags = (LOCKPARENT | LOCKLEAF | HASBUF | SAVENAME | ISLASTCN);
cn->cn_lkflags = LK_EXCLUSIVE;
cn->cn_thread = td;
cn->cn_cred = cnp->cn_cred;
cn->cn_nameptr = cn->cn_pnbuf;
if (nameiop == DELETE)
cn->cn_flags |= (cnp->cn_flags & (DOWHITEOUT | SAVESTART));
else if (RENAME == nameiop)
cn->cn_flags |= (cnp->cn_flags & SAVESTART);
else if (nameiop == CREATE)
cn->cn_flags |= NOCACHE;
vref(dvp);
VOP_UNLOCK(dvp, LK_RELEASE);
if ((error = relookup(dvp, vpp, cn))) {
uma_zfree(namei_zone, cn->cn_pnbuf);
cn->cn_flags &= ~HASBUF;
vn_lock(dvp, LK_EXCLUSIVE | LK_RETRY);
} else
vrele(dvp);
return (error);
}
/*
* relookup for CREATE namei operation.
*
* dvp is unionfs vnode. dvp should be locked.
*
* If it called 'unionfs_copyfile' function by unionfs_link etc,
* VOP_LOOKUP information is broken.
* So it need relookup in order to create link etc.
*/
int
unionfs_relookup_for_create(struct vnode *dvp, struct componentname *cnp,
struct thread *td)
{
int error;
struct vnode *udvp;
struct vnode *vp;
struct componentname cn;
udvp = UNIONFSVPTOUPPERVP(dvp);
vp = NULLVP;
error = unionfs_relookup(udvp, &vp, cnp, &cn, td, cnp->cn_nameptr,
strlen(cnp->cn_nameptr), CREATE);
if (error)
return (error);
if (vp != NULLVP) {
if (udvp == vp)
vrele(vp);
else
vput(vp);
error = EEXIST;
}
if (cn.cn_flags & HASBUF) {
uma_zfree(namei_zone, cn.cn_pnbuf);
cn.cn_flags &= ~HASBUF;
}
if (!error) {
cn.cn_flags |= (cnp->cn_flags & HASBUF);
cnp->cn_flags = cn.cn_flags;
}
return (error);
}
/*
* relookup for DELETE namei operation.
*
* dvp is unionfs vnode. dvp should be locked.
*/
int
unionfs_relookup_for_delete(struct vnode *dvp, struct componentname *cnp,
struct thread *td)
{
int error;
struct vnode *udvp;
struct vnode *vp;
struct componentname cn;
udvp = UNIONFSVPTOUPPERVP(dvp);
vp = NULLVP;
error = unionfs_relookup(udvp, &vp, cnp, &cn, td, cnp->cn_nameptr,
strlen(cnp->cn_nameptr), DELETE);
if (error)
return (error);
if (vp == NULLVP)
error = ENOENT;
else {
if (udvp == vp)
vrele(vp);
else
vput(vp);
}
if (cn.cn_flags & HASBUF) {
uma_zfree(namei_zone, cn.cn_pnbuf);
cn.cn_flags &= ~HASBUF;
}
if (!error) {
cn.cn_flags |= (cnp->cn_flags & HASBUF);
cnp->cn_flags = cn.cn_flags;
}
return (error);
}
/*
* relookup for RENAME namei operation.
*
* dvp is unionfs vnode. dvp should be locked.
*/
int
unionfs_relookup_for_rename(struct vnode *dvp, struct componentname *cnp,
struct thread *td)
{
int error;
struct vnode *udvp;
struct vnode *vp;
struct componentname cn;
udvp = UNIONFSVPTOUPPERVP(dvp);
vp = NULLVP;
error = unionfs_relookup(udvp, &vp, cnp, &cn, td, cnp->cn_nameptr,
strlen(cnp->cn_nameptr), RENAME);
if (error)
return (error);
if (vp != NULLVP) {
if (udvp == vp)
vrele(vp);
else
vput(vp);
}
if (cn.cn_flags & HASBUF) {
uma_zfree(namei_zone, cn.cn_pnbuf);
cn.cn_flags &= ~HASBUF;
}
if (!error) {
cn.cn_flags |= (cnp->cn_flags & HASBUF);
cnp->cn_flags = cn.cn_flags;
}
return (error);
}
/*
* Update the unionfs_node.
*
* uvp is new locked upper vnode. unionfs vnode's lock will be exchanged to the
* uvp's lock and lower's lock will be unlocked.
*/
static void
unionfs_node_update(struct unionfs_node *unp, struct vnode *uvp,
struct thread *td)
{
unsigned count, lockrec;
struct vnode *vp;
struct vnode *lvp;
struct vnode *dvp;
vp = UNIONFSTOV(unp);
lvp = unp->un_lowervp;
ASSERT_VOP_ELOCKED(lvp, "unionfs_node_update");
dvp = unp->un_dvp;
/*
* lock update
*/
VI_LOCK(vp);
unp->un_uppervp = uvp;
vp->v_vnlock = uvp->v_vnlock;
VI_UNLOCK(vp);
lockrec = lvp->v_vnlock->lk_recurse;
for (count = 0; count < lockrec; count++)
vn_lock(uvp, LK_EXCLUSIVE | LK_CANRECURSE | LK_RETRY);
/*
* cache update
*/
if (unp->un_path != NULL && dvp != NULLVP && vp->v_type == VDIR) {
static struct unionfs_node_hashhead *hd;
VI_LOCK(dvp);
hd = unionfs_get_hashhead(dvp, unp->un_path);
LIST_REMOVE(unp, un_hash);
LIST_INSERT_HEAD(hd, unp, un_hash);
VI_UNLOCK(dvp);
}
}
/*
* Create a new shadow dir.
*
* udvp should be locked on entry and will be locked on return.
*
* If no error returned, unp will be updated.
*/
int
unionfs_mkshadowdir(struct unionfs_mount *ump, struct vnode *udvp,
struct unionfs_node *unp, struct componentname *cnp,
struct thread *td)
{
int error;
struct vnode *lvp;
struct vnode *uvp;
struct vattr va;
struct vattr lva;
struct componentname cn;
struct mount *mp;
struct ucred *cred;
struct ucred *credbk;
struct uidinfo *rootinfo;
if (unp->un_uppervp != NULLVP)
return (EEXIST);
lvp = unp->un_lowervp;
uvp = NULLVP;
credbk = cnp->cn_cred;
/* Authority change to root */
rootinfo = uifind((uid_t)0);
cred = crdup(cnp->cn_cred);
/*
* The calls to chgproccnt() are needed to compensate for change_ruid()
* calling chgproccnt().
*/
chgproccnt(cred->cr_ruidinfo, 1, 0);
change_euid(cred, rootinfo);
change_ruid(cred, rootinfo);
change_svuid(cred, (uid_t)0);
uifree(rootinfo);
cnp->cn_cred = cred;
memset(&cn, 0, sizeof(cn));
if ((error = VOP_GETATTR(lvp, &lva, cnp->cn_cred)))
goto unionfs_mkshadowdir_abort;
if ((error = unionfs_relookup(udvp, &uvp, cnp, &cn, td, cnp->cn_nameptr, cnp->cn_namelen, CREATE)))
goto unionfs_mkshadowdir_abort;
if (uvp != NULLVP) {
if (udvp == uvp)
vrele(uvp);
else
vput(uvp);
error = EEXIST;
goto unionfs_mkshadowdir_free_out;
}
if ((error = vn_start_write(udvp, &mp, V_WAIT | PCATCH)))
goto unionfs_mkshadowdir_free_out;
unionfs_create_uppervattr_core(ump, &lva, &va, td);
error = VOP_MKDIR(udvp, &uvp, &cn, &va);
if (!error) {
unionfs_node_update(unp, uvp, td);
/*
* XXX The bug which cannot set uid/gid was corrected.
* Ignore errors.
*/
va.va_type = VNON;
VOP_SETATTR(uvp, &va, cn.cn_cred);
}
vn_finished_write(mp);
unionfs_mkshadowdir_free_out:
if (cn.cn_flags & HASBUF) {
uma_zfree(namei_zone, cn.cn_pnbuf);
cn.cn_flags &= ~HASBUF;
}
unionfs_mkshadowdir_abort:
cnp->cn_cred = credbk;
chgproccnt(cred->cr_ruidinfo, -1, 0);
crfree(cred);
return (error);
}
/*
* Create a new whiteout.
*
* dvp should be locked on entry and will be locked on return.
*/
int
unionfs_mkwhiteout(struct vnode *dvp, struct componentname *cnp,
struct thread *td, char *path)
{
int error;
struct vnode *wvp;
struct componentname cn;
struct mount *mp;
if (path == NULL)
path = cnp->cn_nameptr;
wvp = NULLVP;
if ((error = unionfs_relookup(dvp, &wvp, cnp, &cn, td, path, strlen(path), CREATE)))
return (error);
if (wvp != NULLVP) {
if (cn.cn_flags & HASBUF) {
uma_zfree(namei_zone, cn.cn_pnbuf);
cn.cn_flags &= ~HASBUF;
}
if (dvp == wvp)
vrele(wvp);
else
vput(wvp);
return (EEXIST);
}
if ((error = vn_start_write(dvp, &mp, V_WAIT | PCATCH)))
goto unionfs_mkwhiteout_free_out;
error = VOP_WHITEOUT(dvp, &cn, CREATE);
vn_finished_write(mp);
unionfs_mkwhiteout_free_out:
if (cn.cn_flags & HASBUF) {
uma_zfree(namei_zone, cn.cn_pnbuf);
cn.cn_flags &= ~HASBUF;
}
return (error);
}
/*
* Create a new vnode for create a new shadow file.
*
* If an error is returned, *vpp will be invalid, otherwise it will hold a
* locked, referenced and opened vnode.
*
* unp is never updated.
*/
static int
unionfs_vn_create_on_upper(struct vnode **vpp, struct vnode *udvp,
struct unionfs_node *unp, struct vattr *uvap,
struct thread *td)
{
struct unionfs_mount *ump;
struct vnode *vp;
struct vnode *lvp;
struct ucred *cred;
struct vattr lva;
int fmode;
int error;
struct componentname cn;
ump = MOUNTTOUNIONFSMOUNT(UNIONFSTOV(unp)->v_mount);
vp = NULLVP;
lvp = unp->un_lowervp;
cred = td->td_ucred;
fmode = FFLAGS(O_WRONLY | O_CREAT | O_TRUNC | O_EXCL);
error = 0;
if ((error = VOP_GETATTR(lvp, &lva, cred)) != 0)
return (error);
unionfs_create_uppervattr_core(ump, &lva, uvap, td);
if (unp->un_path == NULL)
panic("unionfs: un_path is null");
cn.cn_namelen = strlen(unp->un_path);
cn.cn_pnbuf = uma_zalloc(namei_zone, M_WAITOK);
bcopy(unp->un_path, cn.cn_pnbuf, cn.cn_namelen + 1);
cn.cn_nameiop = CREATE;
cn.cn_flags = (LOCKPARENT | LOCKLEAF | HASBUF | SAVENAME | ISLASTCN);
cn.cn_lkflags = LK_EXCLUSIVE;
cn.cn_thread = td;
cn.cn_cred = cred;
cn.cn_nameptr = cn.cn_pnbuf;
vref(udvp);
if ((error = relookup(udvp, &vp, &cn)) != 0)
goto unionfs_vn_create_on_upper_free_out2;
vrele(udvp);
if (vp != NULLVP) {
if (vp == udvp)
vrele(vp);
else
vput(vp);
error = EEXIST;
goto unionfs_vn_create_on_upper_free_out1;
}
if ((error = VOP_CREATE(udvp, &vp, &cn, uvap)) != 0)
goto unionfs_vn_create_on_upper_free_out1;
if ((error = VOP_OPEN(vp, fmode, cred, td, NULL)) != 0) {
vput(vp);
goto unionfs_vn_create_on_upper_free_out1;
}
VOP_ADD_WRITECOUNT(vp, 1);
CTR3(KTR_VFS, "%s: vp %p v_writecount increased to %d", __func__, vp,
vp->v_writecount);
*vpp = vp;
unionfs_vn_create_on_upper_free_out1:
VOP_UNLOCK(udvp, LK_RELEASE);
unionfs_vn_create_on_upper_free_out2:
if (cn.cn_flags & HASBUF) {
uma_zfree(namei_zone, cn.cn_pnbuf);
cn.cn_flags &= ~HASBUF;
}
return (error);
}
/*
* Copy from lvp to uvp.
*
* lvp and uvp should be locked and opened on entry and will be locked and
* opened on return.
*/
static int
unionfs_copyfile_core(struct vnode *lvp, struct vnode *uvp,
struct ucred *cred, struct thread *td)
{
int error;
off_t offset;
int count;
int bufoffset;
char *buf;
struct uio uio;
struct iovec iov;
error = 0;
memset(&uio, 0, sizeof(uio));
uio.uio_td = td;
uio.uio_segflg = UIO_SYSSPACE;
uio.uio_offset = 0;
buf = malloc(MAXBSIZE, M_TEMP, M_WAITOK);
while (error == 0) {
offset = uio.uio_offset;
uio.uio_iov = &iov;
uio.uio_iovcnt = 1;
iov.iov_base = buf;
iov.iov_len = MAXBSIZE;
uio.uio_resid = iov.iov_len;
uio.uio_rw = UIO_READ;
if ((error = VOP_READ(lvp, &uio, 0, cred)) != 0)
break;
if ((count = MAXBSIZE - uio.uio_resid) == 0)
break;
bufoffset = 0;
while (bufoffset < count) {
uio.uio_iov = &iov;
uio.uio_iovcnt = 1;
iov.iov_base = buf + bufoffset;
iov.iov_len = count - bufoffset;
uio.uio_offset = offset + bufoffset;
uio.uio_resid = iov.iov_len;
uio.uio_rw = UIO_WRITE;
if ((error = VOP_WRITE(uvp, &uio, 0, cred)) != 0)
break;
bufoffset += (count - bufoffset) - uio.uio_resid;
}
uio.uio_offset = offset + bufoffset;
}
free(buf, M_TEMP);
return (error);
}
/*
* Copy file from lower to upper.
*
* If you need copy of the contents, set 1 to docopy. Otherwise, set 0 to
* docopy.
*
* If no error returned, unp will be updated.
*/
int
unionfs_copyfile(struct unionfs_node *unp, int docopy, struct ucred *cred,
struct thread *td)
{
int error;
struct mount *mp;
struct vnode *udvp;
struct vnode *lvp;
struct vnode *uvp;
struct vattr uva;
lvp = unp->un_lowervp;
uvp = NULLVP;
if ((UNIONFSTOV(unp)->v_mount->mnt_flag & MNT_RDONLY))
return (EROFS);
if (unp->un_dvp == NULLVP)
return (EINVAL);
if (unp->un_uppervp != NULLVP)
return (EEXIST);
udvp = VTOUNIONFS(unp->un_dvp)->un_uppervp;
if (udvp == NULLVP)
return (EROFS);
if ((udvp->v_mount->mnt_flag & MNT_RDONLY))
return (EROFS);
error = VOP_ACCESS(lvp, VREAD, cred, td);
if (error != 0)
return (error);
if ((error = vn_start_write(udvp, &mp, V_WAIT | PCATCH)) != 0)
return (error);
error = unionfs_vn_create_on_upper(&uvp, udvp, unp, &uva, td);
if (error != 0) {
vn_finished_write(mp);
return (error);
}
if (docopy != 0) {
error = VOP_OPEN(lvp, FREAD, cred, td, NULL);
if (error == 0) {
error = unionfs_copyfile_core(lvp, uvp, cred, td);
VOP_CLOSE(lvp, FREAD, cred, td);
}
}
VOP_CLOSE(uvp, FWRITE, cred, td);
VOP_ADD_WRITECOUNT(uvp, -1);
CTR3(KTR_VFS, "%s: vp %p v_writecount decreased to %d", __func__, uvp,
uvp->v_writecount);
vn_finished_write(mp);
if (error == 0) {
/* Reset the attributes. Ignore errors. */
uva.va_type = VNON;
VOP_SETATTR(uvp, &uva, cred);
}
unionfs_node_update(unp, uvp, td);
return (error);
}
/*
* It checks whether vp can rmdir. (check empty)
*
* vp is unionfs vnode.
* vp should be locked.
*/
int
unionfs_check_rmdir(struct vnode *vp, struct ucred *cred, struct thread *td)
{
int error;
int eofflag;
int lookuperr;
struct vnode *uvp;
struct vnode *lvp;
struct vnode *tvp;
struct vattr va;
struct componentname cn;
/*
* The size of buf needs to be larger than DIRBLKSIZ.
*/
char buf[256 * 6];
struct dirent *dp;
struct dirent *edp;
struct uio uio;
struct iovec iov;
ASSERT_VOP_ELOCKED(vp, "unionfs_check_rmdir");
eofflag = 0;
uvp = UNIONFSVPTOUPPERVP(vp);
lvp = UNIONFSVPTOLOWERVP(vp);
/* check opaque */
if ((error = VOP_GETATTR(uvp, &va, cred)) != 0)
return (error);
if (va.va_flags & OPAQUE)
return (0);
/* open vnode */
#ifdef MAC
if ((error = mac_vnode_check_open(cred, vp, VEXEC|VREAD)) != 0)
return (error);
#endif
if ((error = VOP_ACCESS(vp, VEXEC|VREAD, cred, td)) != 0)
return (error);
if ((error = VOP_OPEN(vp, FREAD, cred, td, NULL)) != 0)
return (error);
uio.uio_rw = UIO_READ;
uio.uio_segflg = UIO_SYSSPACE;
uio.uio_td = td;
uio.uio_offset = 0;
#ifdef MAC
error = mac_vnode_check_readdir(td->td_ucred, lvp);
#endif
while (!error && !eofflag) {
iov.iov_base = buf;
iov.iov_len = sizeof(buf);
uio.uio_iov = &iov;
uio.uio_iovcnt = 1;
uio.uio_resid = iov.iov_len;
error = VOP_READDIR(lvp, &uio, cred, &eofflag, NULL, NULL);
if (error != 0)
break;
if (eofflag == 0 && uio.uio_resid == sizeof(buf)) {
#ifdef DIAGNOSTIC
panic("bad readdir response from lower FS.");
#endif
break;
}
edp = (struct dirent*)&buf[sizeof(buf) - uio.uio_resid];
for (dp = (struct dirent*)buf; !error && dp < edp;
dp = (struct dirent*)((caddr_t)dp + dp->d_reclen)) {
if (dp->d_type == DT_WHT || dp->d_fileno == 0 ||
(dp->d_namlen == 1 && dp->d_name[0] == '.') ||
(dp->d_namlen == 2 && !bcmp(dp->d_name, "..", 2)))
continue;
cn.cn_namelen = dp->d_namlen;
cn.cn_pnbuf = NULL;
cn.cn_nameptr = dp->d_name;
cn.cn_nameiop = LOOKUP;
cn.cn_flags = (LOCKPARENT | LOCKLEAF | SAVENAME | RDONLY | ISLASTCN);
cn.cn_lkflags = LK_EXCLUSIVE;
cn.cn_thread = td;
cn.cn_cred = cred;
/*
* check entry in lower.
* Sometimes, readdir function returns
* wrong entry.
*/
lookuperr = VOP_LOOKUP(lvp, &tvp, &cn);
if (!lookuperr)
vput(tvp);
else
continue; /* skip entry */
/*
* check entry
* If it has no exist/whiteout entry in upper,
* directory is not empty.
*/
cn.cn_flags = (LOCKPARENT | LOCKLEAF | SAVENAME | RDONLY | ISLASTCN);
lookuperr = VOP_LOOKUP(uvp, &tvp, &cn);
if (!lookuperr)
vput(tvp);
/* ignore exist or whiteout entry */
if (!lookuperr ||
(lookuperr == ENOENT && (cn.cn_flags & ISWHITEOUT)))
continue;
error = ENOTEMPTY;
}
}
/* close vnode */
VOP_CLOSE(vp, FREAD, cred, td);
return (error);
}
#ifdef DIAGNOSTIC
struct vnode *
unionfs_checkuppervp(struct vnode *vp, char *fil, int lno)
{
struct unionfs_node *unp;
unp = VTOUNIONFS(vp);
#ifdef notyet
if (vp->v_op != unionfs_vnodeop_p) {
printf("unionfs_checkuppervp: on non-unionfs-node.\n");
#ifdef KDB
kdb_enter(KDB_WHY_UNIONFS,
"unionfs_checkuppervp: on non-unionfs-node.\n");
#endif
panic("unionfs_checkuppervp");
}
#endif
return (unp->un_uppervp);
}
struct vnode *
unionfs_checklowervp(struct vnode *vp, char *fil, int lno)
{
struct unionfs_node *unp;
unp = VTOUNIONFS(vp);
#ifdef notyet
if (vp->v_op != unionfs_vnodeop_p) {
printf("unionfs_checklowervp: on non-unionfs-node.\n");
#ifdef KDB
kdb_enter(KDB_WHY_UNIONFS,
"unionfs_checklowervp: on non-unionfs-node.\n");
#endif
panic("unionfs_checklowervp");
}
#endif
return (unp->un_lowervp);
}
#endif
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