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b5dc376dfa
freebsd-skq/sys/fs/devfs/devfs_vnops.c
ups b5dc376dfa Add vnode interlocking to devfs. 
This prevents race conditions that can cause pagefaults or devfs
to use arbitrary vnodes.

MFC after:	1 week
2006-07-12 20:25:35 +00:00

1266 lines
29 KiB
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/*-
* Copyright (c) 2000-2004
* Poul-Henning Kamp. All rights reserved.
* Copyright (c) 1989, 1992-1993, 1995
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software donated 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. 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.
*
* @(#)kernfs_vnops.c 8.15 (Berkeley) 5/21/95
* From: FreeBSD: src/sys/miscfs/kernfs/kernfs_vnops.c 1.43
*
* $FreeBSD$
*/
/*
* TODO:
* remove empty directories
* mkdir: want it ?
*/
#include "opt_devfs.h"
#include "opt_mac.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/conf.h>
#include <sys/dirent.h>
#include <sys/fcntl.h>
#include <sys/file.h>
#include <sys/filedesc.h>
#include <sys/filio.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/mac.h>
#include <sys/malloc.h>
#include <sys/mount.h>
#include <sys/namei.h>
#include <sys/proc.h>
#include <sys/stat.h>
#include <sys/sx.h>
#include <sys/time.h>
#include <sys/ttycom.h>
#include <sys/unistd.h>
#include <sys/vnode.h>
static struct vop_vector devfs_vnodeops;
static struct vop_vector devfs_specops;
static struct fileops devfs_ops_f;
#include <fs/devfs/devfs.h>
#include <fs/devfs/devfs_int.h>
static struct mtx devfs_de_interlock;
MTX_SYSINIT(devfs_de_interlock, &devfs_de_interlock, "devfs interlock", MTX_DEF);
static int
devfs_fp_check(struct file *fp, struct cdev **devp, struct cdevsw **dswp)
{
*devp = fp->f_vnode->v_rdev;
if (*devp != fp->f_data)
return (ENXIO);
KASSERT((*devp)->si_refcount > 0,
("devfs: un-referenced struct cdev *(%s)", devtoname(*devp)));
*dswp = dev_refthread(*devp);
if (*dswp == NULL)
return (ENXIO);
return (0);
}
/*
* Construct the fully qualified path name relative to the mountpoint
*/
static char *
devfs_fqpn(char *buf, struct vnode *dvp, struct componentname *cnp)
{
int i;
struct devfs_dirent *de, *dd;
struct devfs_mount *dmp;
dmp = VFSTODEVFS(dvp->v_mount);
dd = dvp->v_data;
i = SPECNAMELEN;
buf[i] = '\0';
i -= cnp->cn_namelen;
if (i < 0)
return (NULL);
bcopy(cnp->cn_nameptr, buf + i, cnp->cn_namelen);
de = dd;
while (de != dmp->dm_rootdir) {
i--;
if (i < 0)
return (NULL);
buf[i] = '/';
i -= de->de_dirent->d_namlen;
if (i < 0)
return (NULL);
bcopy(de->de_dirent->d_name, buf + i,
de->de_dirent->d_namlen);
de = TAILQ_FIRST(&de->de_dlist); /* "." */
de = TAILQ_NEXT(de, de_list); /* ".." */
de = de->de_dir;
}
return (buf + i);
}
int
devfs_allocv(struct devfs_dirent *de, struct mount *mp, struct vnode **vpp, struct thread *td)
{
int error;
struct vnode *vp;
struct cdev *dev;
KASSERT(td == curthread, ("devfs_allocv: td != curthread"));
loop:
mtx_lock(&devfs_de_interlock);
vp = de->de_vnode;
if (vp != NULL) {
VI_LOCK(vp);
mtx_unlock(&devfs_de_interlock);
if (vget(vp, LK_EXCLUSIVE | LK_INTERLOCK, td))
goto loop;
*vpp = vp;
return (0);
}
mtx_unlock(&devfs_de_interlock);
if (de->de_dirent->d_type == DT_CHR) {
if (!(de->de_cdp->cdp_flags & CDP_ACTIVE))
return (ENOENT);
dev = &de->de_cdp->cdp_c;
} else {
dev = NULL;
}
error = getnewvnode("devfs", mp, &devfs_vnodeops, &vp);
if (error != 0) {
printf("devfs_allocv: failed to allocate new vnode\n");
return (error);
}
if (de->de_dirent->d_type == DT_CHR) {
vp->v_type = VCHR;
VI_LOCK(vp);
dev_lock();
dev_refl(dev);
vp->v_rdev = dev;
KASSERT(vp->v_usecount == 1,
("%s %d (%d)\n", __func__, __LINE__, vp->v_usecount));
dev->si_usecount += vp->v_usecount;
dev_unlock();
VI_UNLOCK(vp);
vp->v_op = &devfs_specops;
} else if (de->de_dirent->d_type == DT_DIR) {
vp->v_type = VDIR;
} else if (de->de_dirent->d_type == DT_LNK) {
vp->v_type = VLNK;
} else {
vp->v_type = VBAD;
}
mtx_lock(&devfs_de_interlock);
vp->v_data = de;
de->de_vnode = vp;
mtx_unlock(&devfs_de_interlock);
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td);
#ifdef MAC
mac_associate_vnode_devfs(mp, de, vp);
#endif
*vpp = vp;
return (0);
}
static int
devfs_access(struct vop_access_args *ap)
{
struct vnode *vp = ap->a_vp;
struct devfs_dirent *de;
int error;
de = vp->v_data;
if (vp->v_type == VDIR)
de = de->de_dir;
error = vaccess(vp->v_type, de->de_mode, de->de_uid, de->de_gid,
ap->a_mode, ap->a_cred, NULL);
if (!error)
return (error);
if (error != EACCES)
return (error);
/* We do, however, allow access to the controlling terminal */
if (!(ap->a_td->td_proc->p_flag & P_CONTROLT))
return (error);
if (ap->a_td->td_proc->p_session->s_ttyvp == de->de_vnode)
return (0);
return (error);
}
/* ARGSUSED */
static int
devfs_advlock(struct vop_advlock_args *ap)
{
return (ap->a_flags & F_FLOCK ? EOPNOTSUPP : EINVAL);
}
/* ARGSUSED */
static int
devfs_close(struct vop_close_args *ap)
{
struct vnode *vp = ap->a_vp, *oldvp;
struct thread *td = ap->a_td;
struct cdev *dev = vp->v_rdev;
struct cdevsw *dsw;
int error;
/*
* Hack: a tty device that is a controlling terminal
* has a reference from the session structure.
* We cannot easily tell that a character device is
* a controlling terminal, unless it is the closing
* process' controlling terminal. In that case,
* if the reference count is 2 (this last descriptor
* plus the session), release the reference from the session.
*/
oldvp = NULL;
sx_xlock(&proctree_lock);
if (td && vp == td->td_proc->p_session->s_ttyvp) {
SESS_LOCK(td->td_proc->p_session);
VI_LOCK(vp);
if (count_dev(dev) == 2 && (vp->v_iflag & VI_DOOMED) == 0) {
td->td_proc->p_session->s_ttyvp = NULL;
oldvp = vp;
}
VI_UNLOCK(vp);
SESS_UNLOCK(td->td_proc->p_session);
}
sx_xunlock(&proctree_lock);
if (oldvp != NULL)
vrele(oldvp);
/*
* We do not want to really close the device if it
* is still in use unless we are trying to close it
* forcibly. Since every use (buffer, vnode, swap, cmap)
* holds a reference to the vnode, and because we mark
* any other vnodes that alias this device, when the
* sum of the reference counts on all the aliased
* vnodes descends to one, we are on last close.
*/
dsw = dev_refthread(dev);
if (dsw == NULL)
return (ENXIO);
VI_LOCK(vp);
if (vp->v_iflag & VI_DOOMED) {
/* Forced close. */
} else if (dsw->d_flags & D_TRACKCLOSE) {
/* Keep device updated on status. */
} else if (count_dev(dev) > 1) {
VI_UNLOCK(vp);
dev_relthread(dev);
return (0);
}
VI_UNLOCK(vp);
KASSERT(dev->si_refcount > 0,
("devfs_close() on un-referenced struct cdev *(%s)", devtoname(dev)));
if (!(dsw->d_flags & D_NEEDGIANT)) {
DROP_GIANT();
error = dsw->d_close(dev, ap->a_fflag, S_IFCHR, td);
PICKUP_GIANT();
} else {
error = dsw->d_close(dev, ap->a_fflag, S_IFCHR, td);
}
dev_relthread(dev);
return (error);
}
static int
devfs_close_f(struct file *fp, struct thread *td)
{
return (vnops.fo_close(fp, td));
}
/* ARGSUSED */
static int
devfs_fsync(struct vop_fsync_args *ap)
{
if (!vn_isdisk(ap->a_vp, NULL))
return (0);
return (vop_stdfsync(ap));
}
static int
devfs_getattr(struct vop_getattr_args *ap)
{
struct vnode *vp = ap->a_vp;
struct vattr *vap = ap->a_vap;
int error = 0;
struct devfs_dirent *de;
struct cdev *dev;
de = vp->v_data;
KASSERT(de != NULL, ("Null dirent in devfs_getattr vp=%p", vp));
if (vp->v_type == VDIR) {
de = de->de_dir;
KASSERT(de != NULL,
("Null dir dirent in devfs_getattr vp=%p", vp));
}
bzero((caddr_t) vap, sizeof(*vap));
vattr_null(vap);
vap->va_uid = de->de_uid;
vap->va_gid = de->de_gid;
vap->va_mode = de->de_mode;
if (vp->v_type == VLNK)
vap->va_size = strlen(de->de_symlink);
else if (vp->v_type == VDIR)
vap->va_size = vap->va_bytes = DEV_BSIZE;
else
vap->va_size = 0;
if (vp->v_type != VDIR)
vap->va_bytes = 0;
vap->va_blocksize = DEV_BSIZE;
vap->va_type = vp->v_type;
#define fix(aa) \
do { \
if ((aa).tv_sec == 0) { \
(aa).tv_sec = boottime.tv_sec; \
(aa).tv_nsec = boottime.tv_usec * 1000; \
} \
} while (0)
if (vp->v_type != VCHR) {
fix(de->de_atime);
vap->va_atime = de->de_atime;
fix(de->de_mtime);
vap->va_mtime = de->de_mtime;
fix(de->de_ctime);
vap->va_ctime = de->de_ctime;
} else {
dev = vp->v_rdev;
fix(dev->si_atime);
vap->va_atime = dev->si_atime;
fix(dev->si_mtime);
vap->va_mtime = dev->si_mtime;
fix(dev->si_ctime);
vap->va_ctime = dev->si_ctime;
vap->va_rdev = dev->si_priv->cdp_inode;
}
vap->va_gen = 0;
vap->va_flags = 0;
vap->va_nlink = de->de_links;
vap->va_fileid = de->de_inode;
return (error);
}
/* ARGSUSED */
static int
devfs_ioctl_f(struct file *fp, u_long com, void *data, struct ucred *cred, struct thread *td)
{
struct cdev *dev;
struct cdevsw *dsw;
struct vnode *vp;
struct vnode *vpold;
int error, i;
const char *p;
struct fiodgname_arg *fgn;
error = devfs_fp_check(fp, &dev, &dsw);
if (error)
return (error);
if (com == FIODTYPE) {
*(int *)data = dsw->d_flags & D_TYPEMASK;
dev_relthread(dev);
return (0);
} else if (com == FIODGNAME) {
fgn = data;
p = devtoname(dev);
i = strlen(p) + 1;
if (i > fgn->len)
error = EINVAL;
else
error = copyout(p, fgn->buf, i);
dev_relthread(dev);
return (error);
}
error = dsw->d_ioctl(dev, com, data, fp->f_flag, td);
dev_relthread(dev);
if (error == ENOIOCTL)
error = ENOTTY;
if (error == 0 && com == TIOCSCTTY) {
vp = fp->f_vnode;
/* Do nothing if reassigning same control tty */
sx_slock(&proctree_lock);
if (td->td_proc->p_session->s_ttyvp == vp) {
sx_sunlock(&proctree_lock);
return (0);
}
mtx_lock(&Giant);
vpold = td->td_proc->p_session->s_ttyvp;
VREF(vp);
SESS_LOCK(td->td_proc->p_session);
td->td_proc->p_session->s_ttyvp = vp;
SESS_UNLOCK(td->td_proc->p_session);
sx_sunlock(&proctree_lock);
/* Get rid of reference to old control tty */
if (vpold)
vrele(vpold);
mtx_unlock(&Giant);
}
return (error);
}
/* ARGSUSED */
static int
devfs_kqfilter_f(struct file *fp, struct knote *kn)
{
struct cdev *dev;
struct cdevsw *dsw;
int error;
error = devfs_fp_check(fp, &dev, &dsw);
if (error)
return (error);
error = dsw->d_kqfilter(dev, kn);
dev_relthread(dev);
return (error);
}
static int
devfs_lookupx(struct vop_lookup_args *ap)
{
struct componentname *cnp;
struct vnode *dvp, **vpp;
struct thread *td;
struct devfs_dirent *de, *dd;
struct devfs_dirent **dde;
struct devfs_mount *dmp;
struct cdev *cdev;
int error, flags, nameiop;
char specname[SPECNAMELEN + 1], *pname;
cnp = ap->a_cnp;
vpp = ap->a_vpp;
dvp = ap->a_dvp;
pname = cnp->cn_nameptr;
td = cnp->cn_thread;
flags = cnp->cn_flags;
nameiop = cnp->cn_nameiop;
dmp = VFSTODEVFS(dvp->v_mount);
dd = dvp->v_data;
*vpp = NULLVP;
if ((flags & ISLASTCN) && nameiop == RENAME)
return (EOPNOTSUPP);
if (dvp->v_type != VDIR)
return (ENOTDIR);
if ((flags & ISDOTDOT) && (dvp->v_vflag & VV_ROOT))
return (EIO);
error = VOP_ACCESS(dvp, VEXEC, cnp->cn_cred, td);
if (error)
return (error);
if (cnp->cn_namelen == 1 && *pname == '.') {
if ((flags & ISLASTCN) && nameiop != LOOKUP)
return (EINVAL);
*vpp = dvp;
VREF(dvp);
return (0);
}
if (flags & ISDOTDOT) {
if ((flags & ISLASTCN) && nameiop != LOOKUP)
return (EINVAL);
VOP_UNLOCK(dvp, 0, td);
de = TAILQ_FIRST(&dd->de_dlist); /* "." */
de = TAILQ_NEXT(de, de_list); /* ".." */
de = de->de_dir;
error = devfs_allocv(de, dvp->v_mount, vpp, td);
vn_lock(dvp, LK_EXCLUSIVE | LK_RETRY, td);
return (error);
}
devfs_populate(dmp);
dd = dvp->v_data;
de = devfs_find(dd, cnp->cn_nameptr, cnp->cn_namelen);
while (de == NULL) { /* While(...) so we can use break */
if (nameiop == DELETE)
return (ENOENT);
/*
* OK, we didn't have an entry for the name we were asked for
* so we try to see if anybody can create it on demand.
*/
pname = devfs_fqpn(specname, dvp, cnp);
if (pname == NULL)
break;
cdev = NULL;
EVENTHANDLER_INVOKE(dev_clone,
td->td_ucred, pname, strlen(pname), &cdev);
if (cdev == NULL)
break;
devfs_populate(dmp);
dev_lock();
dde = &cdev->si_priv->cdp_dirents[dmp->dm_idx];
if (dde != NULL && *dde != NULL)
de = *dde;
dev_unlock();
dev_rel(cdev);
break;
}
if (de == NULL || de->de_flags & DE_WHITEOUT) {
if ((nameiop == CREATE || nameiop == RENAME) &&
(flags & (LOCKPARENT | WANTPARENT)) && (flags & ISLASTCN)) {
cnp->cn_flags |= SAVENAME;
return (EJUSTRETURN);
}
return (ENOENT);
}
if ((cnp->cn_nameiop == DELETE) && (flags & ISLASTCN)) {
error = VOP_ACCESS(dvp, VWRITE, cnp->cn_cred, td);
if (error)
return (error);
if (*vpp == dvp) {
VREF(dvp);
*vpp = dvp;
return (0);
}
}
error = devfs_allocv(de, dvp->v_mount, vpp, td);
return (error);
}
static int
devfs_lookup(struct vop_lookup_args *ap)
{
int j;
struct devfs_mount *dmp;
dmp = VFSTODEVFS(ap->a_dvp->v_mount);
sx_xlock(&dmp->dm_lock);
j = devfs_lookupx(ap);
sx_xunlock(&dmp->dm_lock);
return (j);
}
static int
devfs_mknod(struct vop_mknod_args *ap)
{
struct componentname *cnp;
struct vnode *dvp, **vpp;
struct thread *td;
struct devfs_dirent *dd, *de;
struct devfs_mount *dmp;
int error;
/*
* The only type of node we should be creating here is a
* character device, for anything else return EOPNOTSUPP.
*/
if (ap->a_vap->va_type != VCHR)
return (EOPNOTSUPP);
dvp = ap->a_dvp;
dmp = VFSTODEVFS(dvp->v_mount);
sx_xlock(&dmp->dm_lock);
cnp = ap->a_cnp;
vpp = ap->a_vpp;
td = cnp->cn_thread;
dd = dvp->v_data;
error = ENOENT;
TAILQ_FOREACH(de, &dd->de_dlist, de_list) {
if (cnp->cn_namelen != de->de_dirent->d_namlen)
continue;
if (bcmp(cnp->cn_nameptr, de->de_dirent->d_name,
de->de_dirent->d_namlen) != 0)
continue;
if (de->de_flags & DE_WHITEOUT)
break;
goto notfound;
}
if (de == NULL)
goto notfound;
de->de_flags &= ~DE_WHITEOUT;
error = devfs_allocv(de, dvp->v_mount, vpp, td);
notfound:
sx_xunlock(&dmp->dm_lock);
return (error);
}
/* ARGSUSED */
static int
devfs_open(struct vop_open_args *ap)
{
struct thread *td = ap->a_td;
struct vnode *vp = ap->a_vp;
struct cdev *dev = vp->v_rdev;
struct file *fp;
int error;
struct cdevsw *dsw;
if (vp->v_type == VBLK)
return (ENXIO);
if (dev == NULL)
return (ENXIO);
/* Make this field valid before any I/O in d_open. */
if (dev->si_iosize_max == 0)
dev->si_iosize_max = DFLTPHYS;
if (vn_isdisk(vp, NULL) &&
ap->a_cred != FSCRED && (ap->a_mode & FWRITE)) {
/*
* When running in very secure mode, do not allow
* opens for writing of any disks.
* XXX: should be in geom_dev.c, but we lack the cred there.
*/
error = securelevel_ge(td->td_ucred, 2);
if (error)
return (error);
}
dsw = dev_refthread(dev);
if (dsw == NULL)
return (ENXIO);
/* XXX: Special casing of ttys for deadfs. Probably redundant. */
if (dsw->d_flags & D_TTY)
vp->v_vflag |= VV_ISTTY;
VOP_UNLOCK(vp, 0, td);
if(!(dsw->d_flags & D_NEEDGIANT)) {
DROP_GIANT();
if (dsw->d_fdopen != NULL)
error = dsw->d_fdopen(dev, ap->a_mode, td, ap->a_fdidx);
else
error = dsw->d_open(dev, ap->a_mode, S_IFCHR, td);
PICKUP_GIANT();
} else {
if (dsw->d_fdopen != NULL)
error = dsw->d_fdopen(dev, ap->a_mode, td, ap->a_fdidx);
else
error = dsw->d_open(dev, ap->a_mode, S_IFCHR, td);
}
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td);
dev_relthread(dev);
if (error)
return (error);
#if 0 /* /dev/console */
KASSERT(ap->a_fdidx >= 0,
("Could not vnode bypass device on fd %d", ap->a_fdidx));
#else
if(ap->a_fdidx < 0)
return (error);
#endif
/*
* This is a pretty disgustingly long chain, but I am not
* sure there is any better way. Passing the fdidx into
* VOP_OPEN() offers us more information than just passing
* the file *.
*/
fp = ap->a_td->td_proc->p_fd->fd_ofiles[ap->a_fdidx];
KASSERT(fp->f_ops == &badfileops,
("Could not vnode bypass device on fdops %p", fp->f_ops));
fp->f_ops = &devfs_ops_f;
fp->f_data = dev;
return (error);
}
static int
devfs_pathconf(struct vop_pathconf_args *ap)
{
switch (ap->a_name) {
case _PC_MAC_PRESENT:
#ifdef MAC
/*
* If MAC is enabled, devfs automatically supports
* trivial non-persistant label storage.
*/
*ap->a_retval = 1;
#else
*ap->a_retval = 0;
#endif
return (0);
default:
return (vop_stdpathconf(ap));
}
/* NOTREACHED */
}
/* ARGSUSED */
static int
devfs_poll_f(struct file *fp, int events, struct ucred *cred, struct thread *td)
{
struct cdev *dev;
struct cdevsw *dsw;
int error;
error = devfs_fp_check(fp, &dev, &dsw);
if (error)
return (error);
error = dsw->d_poll(dev, events, td);
dev_relthread(dev);
return(error);
}
/*
* Print out the contents of a special device vnode.
*/
static int
devfs_print(struct vop_print_args *ap)
{
printf("\tdev %s\n", devtoname(ap->a_vp->v_rdev));
return (0);
}
/* ARGSUSED */
static int
devfs_read_f(struct file *fp, struct uio *uio, struct ucred *cred, int flags, struct thread *td)
{
struct cdev *dev;
int ioflag, error, resid;
struct cdevsw *dsw;
error = devfs_fp_check(fp, &dev, &dsw);
if (error)
return (error);
resid = uio->uio_resid;
ioflag = fp->f_flag & (O_NONBLOCK | O_DIRECT);
if (ioflag & O_DIRECT)
ioflag |= IO_DIRECT;
if ((flags & FOF_OFFSET) == 0)
uio->uio_offset = fp->f_offset;
error = dsw->d_read(dev, uio, ioflag);
dev_relthread(dev);
if (uio->uio_resid != resid || (error == 0 && resid != 0))
vfs_timestamp(&dev->si_atime);
if ((flags & FOF_OFFSET) == 0)
fp->f_offset = uio->uio_offset;
fp->f_nextoff = uio->uio_offset;
return (error);
}
static int
devfs_readdir(struct vop_readdir_args *ap)
{
int error;
struct uio *uio;
struct dirent *dp;
struct devfs_dirent *dd;
struct devfs_dirent *de;
struct devfs_mount *dmp;
off_t off, oldoff;
int *tmp_ncookies = NULL;
if (ap->a_vp->v_type != VDIR)
return (ENOTDIR);
uio = ap->a_uio;
if (uio->uio_offset < 0)
return (EINVAL);
/*
* XXX: This is a temporary hack to get around this filesystem not
* supporting cookies. We store the location of the ncookies pointer
* in a temporary variable before calling vfs_subr.c:vfs_read_dirent()
* and set the number of cookies to 0. We then set the pointer to
* NULL so that vfs_read_dirent doesn't try to call realloc() on
* ap->a_cookies. Later in this function, we restore the ap->a_ncookies
* pointer to its original location before returning to the caller.
*/
if (ap->a_ncookies != NULL) {
tmp_ncookies = ap->a_ncookies;
*ap->a_ncookies = 0;
ap->a_ncookies = NULL;
}
dmp = VFSTODEVFS(ap->a_vp->v_mount);
sx_xlock(&dmp->dm_lock);
devfs_populate(dmp);
error = 0;
de = ap->a_vp->v_data;
off = 0;
oldoff = uio->uio_offset;
TAILQ_FOREACH(dd, &de->de_dlist, de_list) {
KASSERT(dd->de_cdp != (void *)0xdeadc0de, ("%s %d\n", __func__, __LINE__));
if (dd->de_flags & DE_WHITEOUT)
continue;
if (dd->de_dirent->d_type == DT_DIR)
de = dd->de_dir;
else
de = dd;
dp = dd->de_dirent;
if (dp->d_reclen > uio->uio_resid)
break;
dp->d_fileno = de->de_inode;
if (off >= uio->uio_offset) {
error = vfs_read_dirent(ap, dp, off);
if (error)
break;
}
off += dp->d_reclen;
}
sx_xunlock(&dmp->dm_lock);
uio->uio_offset = off;
/*
* Restore ap->a_ncookies if it wasn't originally NULL in the first
* place.
*/
if (tmp_ncookies != NULL)
ap->a_ncookies = tmp_ncookies;
return (error);
}
static int
devfs_readlink(struct vop_readlink_args *ap)
{
struct devfs_dirent *de;
de = ap->a_vp->v_data;
return (uiomove(de->de_symlink, strlen(de->de_symlink), ap->a_uio));
}
static int
devfs_reclaim(struct vop_reclaim_args *ap)
{
struct vnode *vp = ap->a_vp;
struct devfs_dirent *de;
struct cdev *dev;
mtx_lock(&devfs_de_interlock);
de = vp->v_data;
if (de != NULL) {
de->de_vnode = NULL;
vp->v_data = NULL;
}
mtx_unlock(&devfs_de_interlock);
vnode_destroy_vobject(vp);
dev = vp->v_rdev;
vp->v_rdev = NULL;
if (dev == NULL)
return (0);
dev_lock();
dev->si_usecount -= vp->v_usecount;
dev_unlock();
dev_rel(dev);
return (0);
}
static int
devfs_remove(struct vop_remove_args *ap)
{
struct vnode *vp = ap->a_vp;
struct devfs_dirent *dd;
struct devfs_dirent *de;
struct devfs_mount *dmp = VFSTODEVFS(vp->v_mount);
sx_xlock(&dmp->dm_lock);
dd = ap->a_dvp->v_data;
de = vp->v_data;
if (de->de_cdp == NULL) {
TAILQ_REMOVE(&dd->de_dlist, de, de_list);
devfs_delete(dmp, de);
} else {
de->de_flags |= DE_WHITEOUT;
}
sx_xunlock(&dmp->dm_lock);
return (0);
}
/*
* Revoke is called on a tty when a terminal session ends. The vnode
* is orphaned by setting v_op to deadfs so we need to let go of it
* as well so that we create a new one next time around.
*
*/
static int
devfs_revoke(struct vop_revoke_args *ap)
{
struct vnode *vp = ap->a_vp, *vp2;
struct cdev *dev;
struct cdev_priv *cdp;
struct devfs_dirent *de;
int i;
KASSERT((ap->a_flags & REVOKEALL) != 0, ("devfs_revoke !REVOKEALL"));
dev = vp->v_rdev;
cdp = dev->si_priv;
for (;;) {
mtx_lock(&devfs_de_interlock);
dev_lock();
vp2 = NULL;
for (i = 0; i <= cdp->cdp_maxdirent; i++) {
de = cdp->cdp_dirents[i];
if (de == NULL)
continue;
vp2 = de->de_vnode;
if (vp2 != NULL) {
de->de_vnode = NULL;
dev_unlock();
VI_LOCK(vp2);
mtx_unlock(&devfs_de_interlock);
vholdl(vp2);
VI_UNLOCK(vp2);
vgone(vp2);
vdrop(vp2);
break;
}
}
if (vp2 != NULL) {
continue;
}
dev_unlock();
mtx_unlock(&devfs_de_interlock);
break;
}
return (0);
}
static int
devfs_rioctl(struct vop_ioctl_args *ap)
{
int error;
struct devfs_mount *dmp;
dmp = VFSTODEVFS(ap->a_vp->v_mount);
sx_xlock(&dmp->dm_lock);
devfs_populate(dmp);
error = devfs_rules_ioctl(dmp, ap->a_command, ap->a_data, ap->a_td);
sx_xunlock(&dmp->dm_lock);
return (error);
}
static int
devfs_rread(struct vop_read_args *ap)
{
if (ap->a_vp->v_type != VDIR)
return (EINVAL);
return (VOP_READDIR(ap->a_vp, ap->a_uio, ap->a_cred, NULL, NULL, NULL));
}
static int
devfs_setattr(struct vop_setattr_args *ap)
{
struct devfs_dirent *de;
struct vattr *vap;
struct vnode *vp;
int c, error;
uid_t uid;
gid_t gid;
vap = ap->a_vap;
vp = ap->a_vp;
if ((vap->va_type != VNON) ||
(vap->va_nlink != VNOVAL) ||
(vap->va_fsid != VNOVAL) ||
(vap->va_fileid != VNOVAL) ||
(vap->va_blocksize != VNOVAL) ||
(vap->va_flags != VNOVAL && vap->va_flags != 0) ||
(vap->va_rdev != VNOVAL) ||
((int)vap->va_bytes != VNOVAL) ||
(vap->va_gen != VNOVAL)) {
return (EINVAL);
}
de = vp->v_data;
if (vp->v_type == VDIR)
de = de->de_dir;
error = c = 0;
if (vap->va_uid == (uid_t)VNOVAL)
uid = de->de_uid;
else
uid = vap->va_uid;
if (vap->va_gid == (gid_t)VNOVAL)
gid = de->de_gid;
else
gid = vap->va_gid;
if (uid != de->de_uid || gid != de->de_gid) {
if (((ap->a_cred->cr_uid != de->de_uid) || uid != de->de_uid ||
(gid != de->de_gid && !groupmember(gid, ap->a_cred))) &&
(error = suser_cred(ap->a_td->td_ucred, SUSER_ALLOWJAIL)) != 0)
return (error);
de->de_uid = uid;
de->de_gid = gid;
c = 1;
}
if (vap->va_mode != (mode_t)VNOVAL) {
if ((ap->a_cred->cr_uid != de->de_uid) &&
(error = suser_cred(ap->a_td->td_ucred, SUSER_ALLOWJAIL)))
return (error);
de->de_mode = vap->va_mode;
c = 1;
}
if (vap->va_atime.tv_sec != VNOVAL || vap->va_mtime.tv_sec != VNOVAL) {
/* See the comment in ufs_vnops::ufs_setattr(). */
if ((error = VOP_ACCESS(vp, VADMIN, ap->a_cred, ap->a_td)) &&
((vap->va_vaflags & VA_UTIMES_NULL) == 0 ||
(error = VOP_ACCESS(vp, VWRITE, ap->a_cred, ap->a_td))))
return (error);
if (vap->va_atime.tv_sec != VNOVAL) {
if (vp->v_type == VCHR)
vp->v_rdev->si_atime = vap->va_atime;
else
de->de_atime = vap->va_atime;
}
if (vap->va_mtime.tv_sec != VNOVAL) {
if (vp->v_type == VCHR)
vp->v_rdev->si_mtime = vap->va_mtime;
else
de->de_mtime = vap->va_mtime;
}
c = 1;
}
if (c) {
if (vp->v_type == VCHR)
vfs_timestamp(&vp->v_rdev->si_ctime);
else
vfs_timestamp(&de->de_mtime);
}
return (0);
}
#ifdef MAC
static int
devfs_setlabel(struct vop_setlabel_args *ap)
{
struct vnode *vp;
struct devfs_dirent *de;
vp = ap->a_vp;
de = vp->v_data;
mac_relabel_vnode(ap->a_cred, vp, ap->a_label);
mac_update_devfsdirent(vp->v_mount, de, vp);
return (0);
}
#endif
static int
devfs_stat_f(struct file *fp, struct stat *sb, struct ucred *cred, struct thread *td)
{
return (vnops.fo_stat(fp, sb, cred, td));
}
static int
devfs_symlink(struct vop_symlink_args *ap)
{
int i, error;
struct devfs_dirent *dd;
struct devfs_dirent *de;
struct devfs_mount *dmp;
struct thread *td;
td = ap->a_cnp->cn_thread;
KASSERT(td == curthread, ("devfs_symlink: td != curthread"));
error = suser(td);
if (error)
return(error);
dmp = VFSTODEVFS(ap->a_dvp->v_mount);
dd = ap->a_dvp->v_data;
de = devfs_newdirent(ap->a_cnp->cn_nameptr, ap->a_cnp->cn_namelen);
de->de_uid = 0;
de->de_gid = 0;
de->de_mode = 0755;
de->de_inode = alloc_unr(devfs_inos);
de->de_dirent->d_type = DT_LNK;
i = strlen(ap->a_target) + 1;
de->de_symlink = malloc(i, M_DEVFS, M_WAITOK);
bcopy(ap->a_target, de->de_symlink, i);
sx_xlock(&dmp->dm_lock);
#ifdef MAC
mac_create_devfs_symlink(ap->a_cnp->cn_cred, dmp->dm_mount, dd, de);
#endif
TAILQ_INSERT_TAIL(&dd->de_dlist, de, de_list);
devfs_allocv(de, ap->a_dvp->v_mount, ap->a_vpp, td);
sx_xunlock(&dmp->dm_lock);
return (0);
}
/* ARGSUSED */
static int
devfs_write_f(struct file *fp, struct uio *uio, struct ucred *cred, int flags, struct thread *td)
{
struct cdev *dev;
int error, ioflag, resid;
struct cdevsw *dsw;
error = devfs_fp_check(fp, &dev, &dsw);
if (error)
return (error);
KASSERT(uio->uio_td == td, ("uio_td %p is not td %p", uio->uio_td, td));
ioflag = fp->f_flag & (O_NONBLOCK | O_DIRECT | O_FSYNC);
if (ioflag & O_DIRECT)
ioflag |= IO_DIRECT;
if ((flags & FOF_OFFSET) == 0)
uio->uio_offset = fp->f_offset;
resid = uio->uio_resid;
error = dsw->d_write(dev, uio, ioflag);
dev_relthread(dev);
if (uio->uio_resid != resid || (error == 0 && resid != 0)) {
vfs_timestamp(&dev->si_ctime);
dev->si_mtime = dev->si_ctime;
}
if ((flags & FOF_OFFSET) == 0)
fp->f_offset = uio->uio_offset;
fp->f_nextoff = uio->uio_offset;
return (error);
}
dev_t
dev2udev(struct cdev *x)
{
if (x == NULL)
return (NODEV);
return (x->si_priv->cdp_inode);
}
static struct fileops devfs_ops_f = {
.fo_read = devfs_read_f,
.fo_write = devfs_write_f,
.fo_ioctl = devfs_ioctl_f,
.fo_poll = devfs_poll_f,
.fo_kqfilter = devfs_kqfilter_f,
.fo_stat = devfs_stat_f,
.fo_close = devfs_close_f,
.fo_flags = DFLAG_PASSABLE | DFLAG_SEEKABLE
};
static struct vop_vector devfs_vnodeops = {
.vop_default = &default_vnodeops,
.vop_access = devfs_access,
.vop_getattr = devfs_getattr,
.vop_ioctl = devfs_rioctl,
.vop_lookup = devfs_lookup,
.vop_mknod = devfs_mknod,
.vop_pathconf = devfs_pathconf,
.vop_read = devfs_rread,
.vop_readdir = devfs_readdir,
.vop_readlink = devfs_readlink,
.vop_reclaim = devfs_reclaim,
.vop_remove = devfs_remove,
.vop_revoke = devfs_revoke,
.vop_setattr = devfs_setattr,
#ifdef MAC
.vop_setlabel = devfs_setlabel,
#endif
.vop_symlink = devfs_symlink,
};
static struct vop_vector devfs_specops = {
.vop_default = &default_vnodeops,
.vop_access = devfs_access,
.vop_advlock = devfs_advlock,
.vop_bmap = VOP_PANIC,
.vop_close = devfs_close,
.vop_create = VOP_PANIC,
.vop_fsync = devfs_fsync,
.vop_getattr = devfs_getattr,
.vop_lease = VOP_NULL,
.vop_link = VOP_PANIC,
.vop_mkdir = VOP_PANIC,
.vop_mknod = VOP_PANIC,
.vop_open = devfs_open,
.vop_pathconf = devfs_pathconf,
.vop_print = devfs_print,
.vop_read = VOP_PANIC,
.vop_readdir = VOP_PANIC,
.vop_readlink = VOP_PANIC,
.vop_reallocblks = VOP_PANIC,
.vop_reclaim = devfs_reclaim,
.vop_remove = devfs_remove,
.vop_rename = VOP_PANIC,
.vop_revoke = devfs_revoke,
.vop_rmdir = VOP_PANIC,
.vop_setattr = devfs_setattr,
#ifdef MAC
.vop_setlabel = devfs_setlabel,
#endif
.vop_strategy = VOP_PANIC,
.vop_symlink = VOP_PANIC,
.vop_write = VOP_PANIC,
};
/*
* Our calling convention to the device drivers used to be that we passed
* vnode.h IO_* flags to read()/write(), but we're moving to fcntl.h O_
* flags instead since that's what open(), close() and ioctl() takes and
* we don't really want vnode.h in device drivers.
* We solved the source compatibility by redefining some vnode flags to
* be the same as the fcntl ones and by sending down the bitwise OR of
* the respective fcntl/vnode flags. These CTASSERTS make sure nobody
* pulls the rug out under this.
*/
CTASSERT(O_NONBLOCK == IO_NDELAY);
CTASSERT(O_FSYNC == IO_SYNC);
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