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freebsd-dev/sys/fs/devfs/devfs_vnops.c
Doug White 16e35dcc39 This is a workaround for a complicated issue involving VFS cookies and devfs. 
The PR and patch have the details. The ultimate fix requires architectural
changes and clarifications to the VFS API, but this will prevent the system
from panicking when someone does "ls /dev" while running in a shell under the
linuxulator.

This issue affects HEAD and RELENG_6 only.

PR:		88249
Submitted by:	"Devon H. O'Dell" <dodell@ixsystems.com>
MFC after:	3 days
2005-11-09 22:03:50 +00:00

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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 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:
vp = de->de_vnode;
if (vp != NULL) {
if (vget(vp, LK_EXCLUSIVE, td))
goto loop;
*vpp = vp;
return (0);
}
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;
}
vp->v_data = de;
de->de_vnode = vp;
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.
*/
/*
* This needs to be rewritten to take the vp interlock into
* consideration.
*/
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;
de = vp->v_data;
if (de != NULL)
de->de_vnode = NULL;
vp->v_data = NULL;
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.
*
* XXX: locking :-(
* XXX: We mess around with other mountpoints without holding their sxlock.
* XXX: We hold the devlock() when we zero their vnode pointer, but is that
* XXX: enough ?
*/
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 (;;) {
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;
de->de_vnode = NULL;
if (vp2 != NULL)
break;
}
dev_unlock();
if (vp2 != NULL) {
vgone(vp2);
continue;
}
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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