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freebsd/sys/fs/fifofs/fifo_vnops.c
Jeff Roberson 8da0046596 - The VI_DOOMED flag now signals the end of a vnode's relationship with
the filesystem.  Check that rather than VI_XLOCK.
 - VOP_INACTIVE should no longer drop the vnode lock.
 - The vnode lock is required around calls to vrecycle() and vgone().

Sponsored by:	Isilon Systems, Inc.
2005-03-13 12:18:25 +00:00

687 lines
16 KiB
C

/*-
* Copyright (c) 1990, 1993, 1995
* The Regents of the University of California. All rights reserved.
*
* 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.
* 4. 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.
*
* @(#)fifo_vnops.c 8.10 (Berkeley) 5/27/95
* $FreeBSD$
*/
#include <sys/param.h>
#include <sys/event.h>
#include <sys/file.h>
#include <sys/filedesc.h>
#include <sys/filio.h>
#include <sys/fcntl.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/malloc.h>
#include <sys/poll.h>
#include <sys/proc.h> /* XXXKSE */
#include <sys/signalvar.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/sx.h>
#include <sys/systm.h>
#include <sys/un.h>
#include <sys/unistd.h>
#include <sys/vnode.h>
#include <fs/fifofs/fifo.h>
static fo_rdwr_t fifo_read_f;
static fo_rdwr_t fifo_write_f;
static fo_ioctl_t fifo_ioctl_f;
static fo_poll_t fifo_poll_f;
static fo_kqfilter_t fifo_kqfilter_f;
static fo_stat_t fifo_stat_f;
static fo_close_t fifo_close_f;
struct fileops fifo_ops_f = {
.fo_read = fifo_read_f,
.fo_write = fifo_write_f,
.fo_ioctl = fifo_ioctl_f,
.fo_poll = fifo_poll_f,
.fo_kqfilter = fifo_kqfilter_f,
.fo_stat = fifo_stat_f,
.fo_close = fifo_close_f,
.fo_flags = DFLAG_PASSABLE | DFLAG_SEEKABLE
};
/*
* This structure is associated with the FIFO vnode and stores
* the state associated with the FIFO.
*/
struct fifoinfo {
struct socket *fi_readsock;
struct socket *fi_writesock;
long fi_readers;
long fi_writers;
};
static vop_print_t fifo_print;
static vop_open_t fifo_open;
static vop_close_t fifo_close;
static vop_ioctl_t fifo_ioctl;
static vop_kqfilter_t fifo_kqfilter;
static vop_pathconf_t fifo_pathconf;
static vop_advlock_t fifo_advlock;
static void filt_fifordetach(struct knote *kn);
static int filt_fiforead(struct knote *kn, long hint);
static void filt_fifowdetach(struct knote *kn);
static int filt_fifowrite(struct knote *kn, long hint);
static struct filterops fiforead_filtops =
{ 1, NULL, filt_fifordetach, filt_fiforead };
static struct filterops fifowrite_filtops =
{ 1, NULL, filt_fifowdetach, filt_fifowrite };
struct vop_vector fifo_specops = {
.vop_default = &default_vnodeops,
.vop_access = VOP_EBADF,
.vop_advlock = fifo_advlock,
.vop_close = fifo_close,
.vop_create = VOP_PANIC,
.vop_getattr = VOP_EBADF,
.vop_ioctl = fifo_ioctl,
.vop_kqfilter = fifo_kqfilter,
.vop_lease = VOP_NULL,
.vop_link = VOP_PANIC,
.vop_mkdir = VOP_PANIC,
.vop_mknod = VOP_PANIC,
.vop_open = fifo_open,
.vop_pathconf = fifo_pathconf,
.vop_print = fifo_print,
.vop_read = VOP_PANIC,
.vop_readdir = VOP_PANIC,
.vop_readlink = VOP_PANIC,
.vop_reallocblks = VOP_PANIC,
.vop_reclaim = VOP_NULL,
.vop_remove = VOP_PANIC,
.vop_rename = VOP_PANIC,
.vop_rmdir = VOP_PANIC,
.vop_setattr = VOP_EBADF,
.vop_symlink = VOP_PANIC,
.vop_write = VOP_PANIC,
};
struct mtx fifo_mtx;
MTX_SYSINIT(fifo, &fifo_mtx, "fifo mutex", MTX_DEF);
/*
* Dispose of fifo resources.
*/
static void
fifo_cleanup(struct vnode *vp)
{
struct fifoinfo *fip = vp->v_fifoinfo;
ASSERT_VOP_LOCKED(vp, "fifo_cleanup");
if (fip->fi_readers == 0 && fip->fi_writers == 0) {
vp->v_fifoinfo = NULL;
(void)soclose(fip->fi_readsock);
(void)soclose(fip->fi_writesock);
FREE(fip, M_VNODE);
}
}
/*
* Open called to set up a new instance of a fifo or
* to find an active instance of a fifo.
*/
/* ARGSUSED */
static int
fifo_open(ap)
struct vop_open_args /* {
struct vnode *a_vp;
int a_mode;
struct ucred *a_cred;
struct thread *a_td;
} */ *ap;
{
struct vnode *vp = ap->a_vp;
struct fifoinfo *fip;
struct thread *td = ap->a_td;
struct ucred *cred = ap->a_cred;
struct socket *rso, *wso;
struct file *fp;
int error;
if ((fip = vp->v_fifoinfo) == NULL) {
MALLOC(fip, struct fifoinfo *, sizeof(*fip), M_VNODE, M_WAITOK);
error = socreate(AF_LOCAL, &rso, SOCK_STREAM, 0, cred, td);
if (error)
goto fail1;
fip->fi_readsock = rso;
error = socreate(AF_LOCAL, &wso, SOCK_STREAM, 0, cred, td);
if (error)
goto fail2;
fip->fi_writesock = wso;
error = uipc_connect2(wso, rso);
if (error) {
(void)soclose(wso);
fail2:
(void)soclose(rso);
fail1:
free(fip, M_VNODE);
return (error);
}
fip->fi_readers = fip->fi_writers = 0;
wso->so_snd.sb_lowat = PIPE_BUF;
SOCKBUF_LOCK(&rso->so_rcv);
rso->so_rcv.sb_state |= SBS_CANTRCVMORE;
SOCKBUF_UNLOCK(&rso->so_rcv);
vp->v_fifoinfo = fip;
}
/*
* General access to fi_readers and fi_writers is protected using
* the vnode lock.
*
* Protect the increment of fi_readers and fi_writers and the
* associated calls to wakeup() with the fifo mutex in addition
* to the vnode lock. This allows the vnode lock to be dropped
* for the msleep() calls below, and using the fifo mutex with
* msleep() prevents the wakeup from being missed.
*/
mtx_lock(&fifo_mtx);
if (ap->a_mode & FREAD) {
fip->fi_readers++;
if (fip->fi_readers == 1) {
SOCKBUF_LOCK(&fip->fi_writesock->so_snd);
fip->fi_writesock->so_snd.sb_state &= ~SBS_CANTSENDMORE;
SOCKBUF_UNLOCK(&fip->fi_writesock->so_snd);
if (fip->fi_writers > 0) {
wakeup(&fip->fi_writers);
sowwakeup(fip->fi_writesock);
}
}
}
if (ap->a_mode & FWRITE) {
if ((ap->a_mode & O_NONBLOCK) && fip->fi_readers == 0) {
mtx_unlock(&fifo_mtx);
return (ENXIO);
}
fip->fi_writers++;
if (fip->fi_writers == 1) {
SOCKBUF_LOCK(&fip->fi_writesock->so_rcv);
fip->fi_readsock->so_rcv.sb_state &= ~SBS_CANTRCVMORE;
SOCKBUF_UNLOCK(&fip->fi_writesock->so_rcv);
if (fip->fi_readers > 0) {
wakeup(&fip->fi_readers);
sorwakeup(fip->fi_writesock);
}
}
}
if ((ap->a_mode & O_NONBLOCK) == 0) {
if ((ap->a_mode & FREAD) && fip->fi_writers == 0) {
VOP_UNLOCK(vp, 0, td);
error = msleep(&fip->fi_readers, &fifo_mtx,
PDROP | PCATCH | PSOCK, "fifoor", 0);
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td);
if (error) {
fip->fi_readers--;
if (fip->fi_readers == 0) {
socantsendmore(fip->fi_writesock);
fifo_cleanup(vp);
}
return (error);
}
mtx_lock(&fifo_mtx);
/*
* We must have got woken up because we had a writer.
* That (and not still having one) is the condition
* that we must wait for.
*/
}
if ((ap->a_mode & FWRITE) && fip->fi_readers == 0) {
VOP_UNLOCK(vp, 0, td);
error = msleep(&fip->fi_writers, &fifo_mtx,
PDROP | PCATCH | PSOCK, "fifoow", 0);
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td);
if (error) {
fip->fi_writers--;
if (fip->fi_writers == 0) {
socantrcvmore(fip->fi_readsock);
fifo_cleanup(vp);
}
return (error);
}
/*
* We must have got woken up because we had
* a reader. That (and not still having one)
* is the condition that we must wait for.
*/
mtx_lock(&fifo_mtx);
}
}
mtx_unlock(&fifo_mtx);
KASSERT(ap->a_fdidx >= 0, ("can't fifo/vnode bypass %d", ap->a_fdidx));
fp = ap->a_td->td_proc->p_fd->fd_ofiles[ap->a_fdidx];
KASSERT(fp->f_ops == &badfileops, ("not badfileops in fifo_open"));
fp->f_ops = &fifo_ops_f;
fp->f_data = fip;
return (0);
}
/*
* Device ioctl operation.
*/
/* ARGSUSED */
static int
fifo_ioctl(ap)
struct vop_ioctl_args /* {
struct vnode *a_vp;
u_long a_command;
caddr_t a_data;
int a_fflag;
struct ucred *a_cred;
struct thread *a_td;
} */ *ap;
{
struct file filetmp; /* Local, so need not be locked. */
int error;
if (ap->a_command == FIONBIO)
return (0);
if (ap->a_fflag & FREAD) {
filetmp.f_data = ap->a_vp->v_fifoinfo->fi_readsock;
filetmp.f_cred = ap->a_cred;
error = soo_ioctl(&filetmp, ap->a_command, ap->a_data,
ap->a_td->td_ucred, ap->a_td);
if (error)
return (error);
}
if (ap->a_fflag & FWRITE) {
filetmp.f_data = ap->a_vp->v_fifoinfo->fi_writesock;
filetmp.f_cred = ap->a_cred;
error = soo_ioctl(&filetmp, ap->a_command, ap->a_data,
ap->a_td->td_ucred, ap->a_td);
if (error)
return (error);
}
return (0);
}
/* ARGSUSED */
static int
fifo_kqfilter(ap)
struct vop_kqfilter_args /* {
struct vnode *a_vp;
struct knote *a_kn;
} */ *ap;
{
struct fifoinfo *fi = ap->a_vp->v_fifoinfo;
struct socket *so;
struct sockbuf *sb;
switch (ap->a_kn->kn_filter) {
case EVFILT_READ:
ap->a_kn->kn_fop = &fiforead_filtops;
so = fi->fi_readsock;
sb = &so->so_rcv;
break;
case EVFILT_WRITE:
ap->a_kn->kn_fop = &fifowrite_filtops;
so = fi->fi_writesock;
sb = &so->so_snd;
break;
default:
return (1);
}
ap->a_kn->kn_hook = (caddr_t)so;
SOCKBUF_LOCK(sb);
knlist_add(&sb->sb_sel.si_note, ap->a_kn, 1);
sb->sb_flags |= SB_KNOTE;
SOCKBUF_UNLOCK(sb);
return (0);
}
static void
filt_fifordetach(struct knote *kn)
{
struct socket *so = (struct socket *)kn->kn_hook;
SOCKBUF_LOCK(&so->so_rcv);
knlist_remove(&so->so_rcv.sb_sel.si_note, kn, 1);
if (knlist_empty(&so->so_rcv.sb_sel.si_note))
so->so_rcv.sb_flags &= ~SB_KNOTE;
SOCKBUF_UNLOCK(&so->so_rcv);
}
static int
filt_fiforead(struct knote *kn, long hint)
{
struct socket *so = (struct socket *)kn->kn_hook;
int need_lock, result;
need_lock = !SOCKBUF_OWNED(&so->so_rcv);
if (need_lock)
SOCKBUF_LOCK(&so->so_rcv);
kn->kn_data = so->so_rcv.sb_cc;
if (so->so_rcv.sb_state & SBS_CANTRCVMORE) {
kn->kn_flags |= EV_EOF;
result = 1;
} else {
kn->kn_flags &= ~EV_EOF;
result = (kn->kn_data > 0);
}
if (need_lock)
SOCKBUF_UNLOCK(&so->so_rcv);
return (result);
}
static void
filt_fifowdetach(struct knote *kn)
{
struct socket *so = (struct socket *)kn->kn_hook;
SOCKBUF_LOCK(&so->so_snd);
knlist_remove(&so->so_snd.sb_sel.si_note, kn, 1);
if (knlist_empty(&so->so_snd.sb_sel.si_note))
so->so_snd.sb_flags &= ~SB_KNOTE;
SOCKBUF_UNLOCK(&so->so_snd);
}
static int
filt_fifowrite(struct knote *kn, long hint)
{
struct socket *so = (struct socket *)kn->kn_hook;
int need_lock, result;
need_lock = !SOCKBUF_OWNED(&so->so_snd);
if (need_lock)
SOCKBUF_LOCK(&so->so_snd);
kn->kn_data = sbspace(&so->so_snd);
if (so->so_snd.sb_state & SBS_CANTSENDMORE) {
kn->kn_flags |= EV_EOF;
result = 1;
} else {
kn->kn_flags &= ~EV_EOF;
result = (kn->kn_data >= so->so_snd.sb_lowat);
}
if (need_lock)
SOCKBUF_UNLOCK(&so->so_snd);
return (result);
}
/*
* Device close routine
*/
/* ARGSUSED */
static int
fifo_close(ap)
struct vop_close_args /* {
struct vnode *a_vp;
int a_fflag;
struct ucred *a_cred;
struct thread *a_td;
} */ *ap;
{
struct vnode *vp = ap->a_vp;
struct fifoinfo *fip = vp->v_fifoinfo;
if (ap->a_fflag & FREAD) {
fip->fi_readers--;
if (fip->fi_readers == 0)
socantsendmore(fip->fi_writesock);
}
if (ap->a_fflag & FWRITE) {
fip->fi_writers--;
if (fip->fi_writers == 0)
socantrcvmore(fip->fi_readsock);
}
fifo_cleanup(vp);
return (0);
}
/*
* Print out internal contents of a fifo vnode.
*/
int
fifo_printinfo(vp)
struct vnode *vp;
{
register struct fifoinfo *fip = vp->v_fifoinfo;
printf(", fifo with %ld readers and %ld writers",
fip->fi_readers, fip->fi_writers);
return (0);
}
/*
* Print out the contents of a fifo vnode.
*/
static int
fifo_print(ap)
struct vop_print_args /* {
struct vnode *a_vp;
} */ *ap;
{
fifo_printinfo(ap->a_vp);
printf("\n");
return (0);
}
/*
* Return POSIX pathconf information applicable to fifo's.
*/
static int
fifo_pathconf(ap)
struct vop_pathconf_args /* {
struct vnode *a_vp;
int a_name;
int *a_retval;
} */ *ap;
{
switch (ap->a_name) {
case _PC_LINK_MAX:
*ap->a_retval = LINK_MAX;
return (0);
case _PC_PIPE_BUF:
*ap->a_retval = PIPE_BUF;
return (0);
case _PC_CHOWN_RESTRICTED:
*ap->a_retval = 1;
return (0);
default:
return (EINVAL);
}
/* NOTREACHED */
}
/*
* Fifo advisory byte-level locks.
*/
/* ARGSUSED */
static int
fifo_advlock(ap)
struct vop_advlock_args /* {
struct vnode *a_vp;
caddr_t a_id;
int a_op;
struct flock *a_fl;
int a_flags;
} */ *ap;
{
return (ap->a_flags & F_FLOCK ? EOPNOTSUPP : EINVAL);
}
static int
fifo_close_f(struct file *fp, struct thread *td)
{
return (vnops.fo_close(fp, td));
}
static int
fifo_ioctl_f(struct file *fp, u_long com, void *data, struct ucred *cred, struct thread *td)
{
struct fifoinfo *fi;
struct file filetmp; /* Local, so need not be locked. */
int error;
error = ENOTTY;
fi = fp->f_data;
if (com == FIONBIO)
return (0);
if (fp->f_flag & FREAD) {
filetmp.f_data = fi->fi_readsock;
filetmp.f_cred = cred;
error = soo_ioctl(&filetmp, com, data, cred, td);
if (error)
return (error);
}
if (fp->f_flag & FWRITE) {
filetmp.f_data = fi->fi_writesock;
filetmp.f_cred = cred;
error = soo_ioctl(&filetmp, com, data, cred, td);
}
return (error);
}
static int
fifo_kqfilter_f(struct file *fp, struct knote *kn)
{
struct fifoinfo *fi;
struct socket *so;
struct sockbuf *sb;
fi = fp->f_data;
switch (kn->kn_filter) {
case EVFILT_READ:
kn->kn_fop = &fiforead_filtops;
so = fi->fi_readsock;
sb = &so->so_rcv;
break;
case EVFILT_WRITE:
kn->kn_fop = &fifowrite_filtops;
so = fi->fi_writesock;
sb = &so->so_snd;
break;
default:
return (1);
}
kn->kn_hook = (caddr_t)so;
SOCKBUF_LOCK(sb);
knlist_add(&sb->sb_sel.si_note, kn, 1);
sb->sb_flags |= SB_KNOTE;
SOCKBUF_UNLOCK(sb);
return (0);
}
static int
fifo_poll_f(struct file *fp, int events, struct ucred *cred, struct thread *td)
{
struct fifoinfo *fip;
struct file filetmp;
int levents, revents = 0;
fip = fp->f_data;
levents = events &
(POLLIN | POLLINIGNEOF | POLLPRI | POLLRDNORM | POLLRDBAND);
if (levents) {
/*
* If POLLIN or POLLRDNORM is requested and POLLINIGNEOF is
* not, then convert the first two to the last one. This
* tells the socket poll function to ignore EOF so that we
* block if there is no writer (and no data). Callers can
* set POLLINIGNEOF to get non-blocking behavior.
*/
if (levents & (POLLIN | POLLRDNORM) &&
!(levents & POLLINIGNEOF)) {
levents &= ~(POLLIN | POLLRDNORM);
levents |= POLLINIGNEOF;
}
filetmp.f_data = fip->fi_readsock;
filetmp.f_cred = cred;
if (filetmp.f_data)
revents |= soo_poll(&filetmp, levents, cred, td);
/* Reverse the above conversion. */
if ((revents & POLLINIGNEOF) && !(events & POLLINIGNEOF)) {
revents |= (events & (POLLIN | POLLRDNORM));
revents &= ~POLLINIGNEOF;
}
}
levents = events & (POLLOUT | POLLWRNORM | POLLWRBAND);
if (events) {
filetmp.f_data = fip->fi_writesock;
filetmp.f_cred = cred;
if (filetmp.f_data) {
revents |= soo_poll(&filetmp, events, cred, td);
}
}
return (revents);
}
static int
fifo_read_f(struct file *fp, struct uio *uio, struct ucred *cred, int flags, struct thread *td)
{
struct fifoinfo *fip;
int error, sflags;
fip = fp->f_data;
KASSERT(uio->uio_rw == UIO_READ,("fifo_read mode"));
if (uio->uio_resid == 0)
return (0);
sflags = (fp->f_flag & FNONBLOCK) ? MSG_NBIO : 0;
error = soreceive(fip->fi_readsock, NULL, uio, NULL, NULL, &sflags);
return (error);
}
static int
fifo_stat_f(struct file *fp, struct stat *sb, struct ucred *cred, struct thread *td)
{
return (vnops.fo_stat(fp, sb, cred, td));
}
static int
fifo_write_f(struct file *fp, struct uio *uio, struct ucred *cred, int flags, struct thread *td)
{
struct fifoinfo *fip;
int error, sflags;
fip = fp->f_data;
KASSERT(uio->uio_rw == UIO_WRITE,("fifo_write mode"));
sflags = (fp->f_flag & FNONBLOCK) ? MSG_NBIO : 0;
error = sosend(fip->fi_writesock, NULL, uio, 0, NULL, sflags, td);
return (error);
}