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/* $OpenBSD: fifo_vnops.c,v 1.58 2017/07/24 15:07:39 mpi Exp $ */
/* $NetBSD: fifo_vnops.c,v 1.18 1996/03/16 23:52:42 christos Exp $ */
/*
* Copyright (c) 1990, 1993
* 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.
* 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.
*
* @(#)fifo_vnops.c 8.4 (Berkeley) 8/10/94
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/time.h>
#include <sys/namei.h>
#include <sys/vnode.h>
#include <sys/lock.h>
#include <sys/protosw.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <sys/file.h>
#include <sys/event.h>
#include <sys/errno.h>
#include <sys/malloc.h>
#include <sys/poll.h>
#include <sys/unistd.h>
#include <miscfs/fifofs/fifo.h>
/*
* 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;
};
struct vops fifo_vops = {
.vop_lookup = vop_generic_lookup,
.vop_create = fifo_badop,
.vop_mknod = fifo_badop,
.vop_open = fifo_open,
.vop_close = fifo_close,
.vop_access = fifo_ebadf,
.vop_getattr = fifo_ebadf,
.vop_setattr = fifo_ebadf,
.vop_read = fifo_read,
.vop_write = fifo_write,
.vop_ioctl = fifo_ioctl,
.vop_poll = fifo_poll,
.vop_kqfilter = fifo_kqfilter,
.vop_revoke = vop_generic_revoke,
.vop_fsync = nullop,
.vop_remove = fifo_badop,
.vop_link = fifo_badop,
.vop_rename = fifo_badop,
.vop_mkdir = fifo_badop,
.vop_rmdir = fifo_badop,
.vop_symlink = fifo_badop,
.vop_readdir = fifo_badop,
.vop_readlink = fifo_badop,
.vop_abortop = fifo_badop,
.vop_inactive = fifo_inactive,
.vop_reclaim = fifo_reclaim,
.vop_lock = vop_generic_lock,
.vop_unlock = vop_generic_unlock,
.vop_bmap = vop_generic_bmap,
.vop_strategy = fifo_badop,
.vop_print = fifo_print,
.vop_islocked = vop_generic_islocked,
.vop_pathconf = fifo_pathconf,
.vop_advlock = fifo_advlock,
.vop_bwrite = nullop
};
void filt_fifordetach(struct knote *kn);
int filt_fiforead(struct knote *kn, long hint);
void filt_fifowdetach(struct knote *kn);
int filt_fifowrite(struct knote *kn, long hint);
struct filterops fiforead_filtops =
{ 1, NULL, filt_fifordetach, filt_fiforead };
struct filterops fifowrite_filtops =
{ 1, NULL, filt_fifowdetach, filt_fifowrite };
/*
* Open called to set up a new instance of a fifo or
* to find an active instance of a fifo.
*/
/* ARGSUSED */
int
fifo_open(void *v)
{
struct vop_open_args *ap = v;
struct vnode *vp = ap->a_vp;
struct fifoinfo *fip;
struct proc *p = ap->a_p;
struct socket *rso, *wso;
int s, error;
if ((fip = vp->v_fifoinfo) == NULL) {
fip = malloc(sizeof(*fip), M_VNODE, M_WAITOK);
vp->v_fifoinfo = fip;
if ((error = socreate(AF_LOCAL, &rso, SOCK_STREAM, 0)) != 0) {
free(fip, M_VNODE, sizeof *fip);
vp->v_fifoinfo = NULL;
return (error);
}
fip->fi_readsock = rso;
if ((error = socreate(AF_LOCAL, &wso, SOCK_STREAM, 0)) != 0) {
(void)soclose(rso);
free(fip, M_VNODE, sizeof *fip);
vp->v_fifoinfo = NULL;
return (error);
}
fip->fi_writesock = wso;
/*
* XXXSMP
* We only lock `wso' because AF_LOCAL sockets are
* still relying on the KERNEL_LOCK().
*/
s = solock(wso);
if ((error = soconnect2(wso, rso)) != 0) {
sounlock(s);
(void)soclose(wso);
(void)soclose(rso);
free(fip, M_VNODE, sizeof *fip);
vp->v_fifoinfo = NULL;
return (error);
}
fip->fi_readers = fip->fi_writers = 0;
wso->so_state |= SS_CANTSENDMORE;
wso->so_snd.sb_lowat = PIPE_BUF;
} else {
rso = fip->fi_readsock;
wso = fip->fi_writesock;
s = solock(wso);
}
if (ap->a_mode & FREAD) {
fip->fi_readers++;
if (fip->fi_readers == 1) {
wso->so_state &= ~SS_CANTSENDMORE;
if (fip->fi_writers > 0)
wakeup(&fip->fi_writers);
}
}
if (ap->a_mode & FWRITE) {
fip->fi_writers++;
if ((ap->a_mode & O_NONBLOCK) && fip->fi_readers == 0) {
error = ENXIO;
sounlock(s);
goto bad;
}
if (fip->fi_writers == 1) {
rso->so_state &= ~(SS_CANTRCVMORE|SS_ISDISCONNECTED);
if (fip->fi_readers > 0)
wakeup(&fip->fi_readers);
}
}
sounlock(s);
if ((ap->a_mode & O_NONBLOCK) == 0) {
if ((ap->a_mode & FREAD) && fip->fi_writers == 0) {
VOP_UNLOCK(vp, p);
error = tsleep(&fip->fi_readers,
PCATCH | PSOCK, "fifor", 0);
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p);
if (error)
goto bad;
}
if ((ap->a_mode & FWRITE) && fip->fi_readers == 0) {
VOP_UNLOCK(vp, p);
error = tsleep(&fip->fi_writers,
PCATCH | PSOCK, "fifow", 0);
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p);
if (error)
goto bad;
}
}
return (0);
bad:
VOP_CLOSE(vp, ap->a_mode, ap->a_cred, ap->a_p);
return (error);
}
/*
* Vnode op for read
*/
/* ARGSUSED */
int
fifo_read(void *v)
{
struct vop_read_args *ap = v;
struct uio *uio = ap->a_uio;
struct socket *rso = ap->a_vp->v_fifoinfo->fi_readsock;
struct proc *p = uio->uio_procp;
int error;
#ifdef DIAGNOSTIC
if (uio->uio_rw != UIO_READ)
panic("fifo_read mode");
#endif
if (uio->uio_resid == 0)
return (0);
if (ap->a_ioflag & IO_NDELAY)
rso->so_state |= SS_NBIO;
VOP_UNLOCK(ap->a_vp, p);
error = soreceive(rso, NULL, uio, NULL, NULL, NULL, 0);
vn_lock(ap->a_vp, LK_EXCLUSIVE | LK_RETRY, p);
if (ap->a_ioflag & IO_NDELAY) {
rso->so_state &= ~SS_NBIO;
if (error == EWOULDBLOCK &&
ap->a_vp->v_fifoinfo->fi_writers == 0)
error = 0;
}
return (error);
}
/*
* Vnode op for write
*/
/* ARGSUSED */
int
fifo_write(void *v)
{
struct vop_write_args *ap = v;
struct socket *wso = ap->a_vp->v_fifoinfo->fi_writesock;
struct proc *p = ap->a_uio->uio_procp;
int error;
#ifdef DIAGNOSTIC
if (ap->a_uio->uio_rw != UIO_WRITE)
panic("fifo_write mode");
#endif
/* XXXSMP changing state w/o lock isn't safe. */
if (ap->a_ioflag & IO_NDELAY)
wso->so_state |= SS_NBIO;
VOP_UNLOCK(ap->a_vp, p);
error = sosend(wso, NULL, ap->a_uio, NULL, NULL, 0);
vn_lock(ap->a_vp, LK_EXCLUSIVE | LK_RETRY, p);
if (ap->a_ioflag & IO_NDELAY)
wso->so_state &= ~SS_NBIO;
return (error);
}
/*
* Device ioctl operation.
*/
/* ARGSUSED */
int
fifo_ioctl(void *v)
{
struct vop_ioctl_args *ap = v;
struct file filetmp;
int error;
if (ap->a_command == FIONBIO)
return (0);
if (ap->a_fflag & FREAD) {
filetmp.f_data = ap->a_vp->v_fifoinfo->fi_readsock;
error = soo_ioctl(&filetmp, ap->a_command, ap->a_data, ap->a_p);
if (error)
return (error);
}
if (ap->a_fflag & FWRITE) {
filetmp.f_data = ap->a_vp->v_fifoinfo->fi_writesock;
error = soo_ioctl(&filetmp, ap->a_command, ap->a_data, ap->a_p);
if (error)
return (error);
}
return (0);
}
/* ARGSUSED */
int
fifo_poll(void *v)
{
struct vop_poll_args *ap = v;
struct socket *rso = ap->a_vp->v_fifoinfo->fi_readsock;
struct socket *wso = ap->a_vp->v_fifoinfo->fi_writesock;
int events = 0;
int revents = 0;
/*
* FIFOs don't support out-of-band or high priority data.
*/
if (ap->a_fflag & FREAD)
events |= ap->a_events & (POLLIN | POLLRDNORM);
if (ap->a_fflag & FWRITE)
events |= ap->a_events & (POLLOUT | POLLWRNORM);
if (events & (POLLIN | POLLRDNORM)) {
if (soreadable(rso))
revents |= events & (POLLIN | POLLRDNORM);
}
/* NOTE: POLLHUP and POLLOUT/POLLWRNORM are mutually exclusive */
if ((rso->so_state & SS_ISDISCONNECTED) && !(ap->a_events & POLL_NOHUP)) {
revents |= POLLHUP;
} else if (events & (POLLOUT | POLLWRNORM)) {
if (sowriteable(wso))
revents |= events & (POLLOUT | POLLWRNORM);
}
if (revents == 0) {
/* We want to return POLLHUP even if no valid events set. */
if (events == 0 && !(ap->a_events & POLL_NOHUP))
events = POLLIN;
if (events & (POLLIN | POLLRDNORM)) {
selrecord(ap->a_p, &rso->so_rcv.sb_sel);
rso->so_rcv.sb_flagsintr |= SB_SEL;
}
if (events & (POLLOUT | POLLWRNORM)) {
selrecord(ap->a_p, &wso->so_snd.sb_sel);
wso->so_snd.sb_flagsintr |= SB_SEL;
}
}
return (revents);
}
int
fifo_inactive(void *v)
{
struct vop_inactive_args *ap = v;
VOP_UNLOCK(ap->a_vp, ap->a_p);
return (0);
}
/*
* Device close routine
*/
/* ARGSUSED */
int
fifo_close(void *v)
{
struct vop_close_args *ap = v;
struct vnode *vp = ap->a_vp;
struct fifoinfo *fip = vp->v_fifoinfo;
int s, error1 = 0, error2 = 0;
if (fip == NULL)
return (0);
if (ap->a_fflag & FREAD) {
if (--fip->fi_readers == 0) {
struct socket *wso = fip->fi_writesock;
s = solock(wso);
socantsendmore(wso);
sounlock(s);
}
}
if (ap->a_fflag & FWRITE) {
if (--fip->fi_writers == 0) {
struct socket *rso = fip->fi_readsock;
s = solock(rso);
/* SS_ISDISCONNECTED will result in POLLHUP */
rso->so_state |= SS_ISDISCONNECTED;
socantrcvmore(rso);
sounlock(s);
}
}
if (fip->fi_readers == 0 && fip->fi_writers == 0) {
error1 = soclose(fip->fi_readsock);
error2 = soclose(fip->fi_writesock);
free(fip, M_VNODE, sizeof *fip);
vp->v_fifoinfo = NULL;
}
return (error1 ? error1 : error2);
}
int
fifo_reclaim(void *v)
{
struct vop_reclaim_args *ap = v;
struct vnode *vp = ap->a_vp;
struct fifoinfo *fip = vp->v_fifoinfo;
if (fip == NULL)
return (0);
soclose(fip->fi_readsock);
soclose(fip->fi_writesock);
free(fip, M_VNODE, sizeof *fip);
vp->v_fifoinfo = NULL;
return (0);
}
/*
* Print out the contents of a fifo vnode.
*/
int
fifo_print(void *v)
{
struct vop_print_args *ap = v;
printf("tag VT_NON");
fifo_printinfo(ap->a_vp);
printf("\n");
return 0;
}
/*
* Print out internal contents of a fifo vnode.
*/
void
fifo_printinfo(struct vnode *vp)
{
struct fifoinfo *fip = vp->v_fifoinfo;
printf(", fifo with %ld readers and %ld writers",
fip->fi_readers, fip->fi_writers);
}
/*
* Return POSIX pathconf information applicable to fifo's.
*/
int
fifo_pathconf(void *v)
{
struct vop_pathconf_args *ap = v;
int error = 0;
switch (ap->a_name) {
case _PC_LINK_MAX:
*ap->a_retval = LINK_MAX;
break;
case _PC_CHOWN_RESTRICTED:
*ap->a_retval = 1;
break;
case _PC_TIMESTAMP_RESOLUTION:
*ap->a_retval = 1;
break;
default:
error = EINVAL;
break;
}
return (error);
}
/*
* Fifo failed operation
*/
/*ARGSUSED*/
int
fifo_ebadf(void *v)
{
return (EBADF);
}
/*
* Fifo advisory byte-level locks.
*/
/* ARGSUSED */
int
fifo_advlock(void *v)
{
return (EOPNOTSUPP);
}
/*
* Fifo bad operation
*/
/*ARGSUSED*/
int
fifo_badop(void *v)
{
panic("fifo_badop called");
/* NOTREACHED */
return(0);
}
int
fifo_kqfilter(void *v)
{
struct vop_kqfilter_args *ap = v;
struct socket *so = (struct socket *)ap->a_vp->v_fifoinfo->fi_readsock;
struct sockbuf *sb;
switch (ap->a_kn->kn_filter) {
case EVFILT_READ:
ap->a_kn->kn_fop = &fiforead_filtops;
sb = &so->so_rcv;
break;
case EVFILT_WRITE:
ap->a_kn->kn_fop = &fifowrite_filtops;
sb = &so->so_snd;
break;
default:
return (EINVAL);
}
ap->a_kn->kn_hook = so;
SLIST_INSERT_HEAD(&sb->sb_sel.si_note, ap->a_kn, kn_selnext);
sb->sb_flags |= SB_KNOTE;
return (0);
}
void
filt_fifordetach(struct knote *kn)
{
struct socket *so = (struct socket *)kn->kn_hook;
SLIST_REMOVE(&so->so_rcv.sb_sel.si_note, kn, knote, kn_selnext);
if (SLIST_EMPTY(&so->so_rcv.sb_sel.si_note))
so->so_rcv.sb_flags &= ~SB_KNOTE;
}
int
filt_fiforead(struct knote *kn, long hint)
{
struct socket *so = (struct socket *)kn->kn_hook;
int rv;
kn->kn_data = so->so_rcv.sb_cc;
if (so->so_state & SS_CANTRCVMORE) {
kn->kn_flags |= EV_EOF;
rv = 1;
} else {
kn->kn_flags &= ~EV_EOF;
rv = (kn->kn_data > 0);
}
return (rv);
}
void
filt_fifowdetach(struct knote *kn)
{
struct socket *so = (struct socket *)kn->kn_hook;
SLIST_REMOVE(&so->so_snd.sb_sel.si_note, kn, knote, kn_selnext);
if (SLIST_EMPTY(&so->so_snd.sb_sel.si_note))
so->so_snd.sb_flags &= ~SB_KNOTE;
}
int
filt_fifowrite(struct knote *kn, long hint)
{
struct socket *so = (struct socket *)kn->kn_hook;
int rv;
kn->kn_data = sbspace(so, &so->so_snd);
if (so->so_state & SS_CANTSENDMORE) {
kn->kn_flags |= EV_EOF;
rv = 1;
} else {
kn->kn_flags &= ~EV_EOF;
rv = (kn->kn_data >= so->so_snd.sb_lowat);
}
return (rv);
}
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