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/*-
* Copyright (c) 1990, 1993, 1995
* The Regents of the University of California.
* Copyright (c) 2005 Robert N. M. Watson
* 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: release/9.1.0/sys/fs/fifofs/fifo_vnops.c 229245 2012-01-01 23:46:08Z kib $
*/
#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>
#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;
static fo_truncate_t fifo_truncate_f;
struct fileops fifo_ops_f = {
.fo_read = fifo_read_f,
.fo_write = fifo_write_f,
.fo_truncate = fifo_truncate_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_chmod = vn_chmod,
.fo_chown = vn_chown,
.fo_flags = DFLAG_PASSABLE
};
/*
* This structure is associated with the FIFO vnode and stores
* the state associated with the FIFO.
* Notes about locking:
* - fi_readsock and fi_writesock are invariant since init time.
* - fi_readers and fi_writers are vnode lock protected.
* - fi_wgen is fif_mtx lock protected.
*/
struct fifoinfo {
struct socket *fi_readsock;
struct socket *fi_writesock;
long fi_readers;
long fi_writers;
int fi_wgen;
};
static vop_print_t fifo_print;
static vop_open_t fifo_open;
static vop_close_t fifo_close;
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 void filt_fifodetach_notsup(struct knote *kn);
static int filt_fifo_notsup(struct knote *kn, long hint);
static struct filterops fiforead_filtops = {
.f_isfd = 1,
.f_detach = filt_fifordetach,
.f_event = filt_fiforead,
};
static struct filterops fifowrite_filtops = {
.f_isfd = 1,
.f_detach = filt_fifowdetach,
.f_event = filt_fifowrite,
};
static struct filterops fifo_notsup_filtops = {
.f_isfd = 1,
.f_detach = filt_fifodetach_notsup,
.f_event = filt_fifo_notsup,
};
struct vop_vector fifo_specops = {
.vop_default = &default_vnodeops,
.vop_advlock = fifo_advlock,
.vop_close = fifo_close,
.vop_create = VOP_PANIC,
.vop_getattr = VOP_EBADF,
.vop_ioctl = VOP_PANIC,
.vop_kqfilter = VOP_PANIC,
.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_ELOCKED(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;
struct file *a_fp;
} */ *ap;
{
struct vnode *vp = ap->a_vp;
struct fifoinfo *fip;
struct thread *td = ap->a_td;
struct ucred *cred = ap->a_cred;
struct file *fp = ap->a_fp;
struct socket *rso, *wso;
int error;
ASSERT_VOP_ELOCKED(vp, "fifo_open");
if (fp == NULL)
return (EINVAL);
if ((fip = vp->v_fifoinfo) == NULL) {
fip = malloc(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 = soconnect2(wso, rso);
/* Close the direction we do not use, so we can get POLLHUP. */
if (error == 0)
error = soshutdown(rso, SHUT_WR);
if (error) {
(void)soclose(wso);
fail2:
(void)soclose(rso);
fail1:
free(fip, M_VNODE);
return (error);
}
fip->fi_wgen = 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);
KASSERT(vp->v_fifoinfo == NULL,
("fifo_open: v_fifoinfo race"));
vp->v_fifoinfo = fip;
}
/*
* Use the fifo_mtx lock here, in addition to the vnode lock,
* in order to allow vnode lock dropping before msleep() calls
* and still avoiding missed wakeups.
*/
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);
}
}
fp->f_seqcount = fip->fi_wgen - fip->fi_writers;
}
if (ap->a_mode & FWRITE) {
if ((ap->a_mode & O_NONBLOCK) && fip->fi_readers == 0) {
mtx_unlock(&fifo_mtx);
if (fip->fi_writers == 0)
fifo_cleanup(vp);
return (ENXIO);
}
fip->fi_writers++;
if (fip->fi_writers == 1) {
SOCKBUF_LOCK(&fip->fi_readsock->so_rcv);
fip->fi_readsock->so_rcv.sb_state &= ~SBS_CANTRCVMORE;
SOCKBUF_UNLOCK(&fip->fi_readsock->so_rcv);
if (fip->fi_readers > 0) {
wakeup(&fip->fi_readers);
sorwakeup(fip->fi_readsock);
}
}
}
if ((ap->a_mode & O_NONBLOCK) == 0) {
if ((ap->a_mode & FREAD) && fip->fi_writers == 0) {
VOP_UNLOCK(vp, 0);
error = msleep(&fip->fi_readers, &fifo_mtx,
PDROP | PCATCH | PSOCK, "fifoor", 0);
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
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);
error = msleep(&fip->fi_writers, &fifo_mtx,
PDROP | PCATCH | PSOCK, "fifoow", 0);
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
if (error) {
fip->fi_writers--;
if (fip->fi_writers == 0) {
socantrcvmore(fip->fi_readsock);
mtx_lock(&fifo_mtx);
fip->fi_wgen++;
mtx_unlock(&fifo_mtx);
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(fp != NULL, ("can't fifo/vnode bypass"));
KASSERT(fp->f_ops == &badfileops, ("not badfileops in fifo_open"));
finit(fp, fp->f_flag, DTYPE_FIFO, fip, &fifo_ops_f);
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;
SOCKBUF_LOCK_ASSERT(&so->so_rcv);
kn->kn_data = so->so_rcv.sb_cc;
if (so->so_rcv.sb_state & SBS_CANTRCVMORE) {
kn->kn_flags |= EV_EOF;
return (1);
} else {
kn->kn_flags &= ~EV_EOF;
return (kn->kn_data > 0);
}
}
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;
SOCKBUF_LOCK_ASSERT(&so->so_snd);
kn->kn_data = sbspace(&so->so_snd);
if (so->so_snd.sb_state & SBS_CANTSENDMORE) {
kn->kn_flags |= EV_EOF;
return (1);
} else {
kn->kn_flags &= ~EV_EOF;
return (kn->kn_data >= so->so_snd.sb_lowat);
}
}
static void
filt_fifodetach_notsup(struct knote *kn)
{
}
static int
filt_fifo_notsup(struct knote *kn, long hint)
{
return (0);
}
/*
* 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;
ASSERT_VOP_ELOCKED(vp, "fifo_close");
if (fip == NULL) {
printf("fifo_close: no v_fifoinfo %p\n", vp);
return (0);
}
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);
mtx_lock(&fifo_mtx);
fip->fi_wgen++;
mtx_unlock(&fifo_mtx);
}
}
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;
if (fip == NULL){
printf(", NULL v_fifoinfo");
return (0);
}
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;
{
printf(" ");
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));
}
/*
* The implementation of ioctl() for named fifos is complicated by the fact
* that we permit O_RDWR fifo file descriptors, meaning that the actions of
* ioctls may have to be applied to both the underlying sockets rather than
* just one. The original implementation simply forward the ioctl to one
* or both sockets based on fp->f_flag. We now consider each ioctl
* separately, as the composition effect requires careful ordering.
*
* We do not blindly pass all ioctls through to the socket in order to avoid
* providing unnecessary ioctls that might be improperly depended on by
* applications (such as socket-specific, routing, and interface ioctls).
*
* Unlike sys_pipe.c, fifos do not implement the deprecated TIOCSPGRP and
* TIOCGPGRP ioctls. Earlier implementations of fifos did forward SIOCSPGRP
* and SIOCGPGRP ioctls, so we might need to re-add those here.
*/
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;
switch (com) {
case FIONBIO:
/*
* Non-blocking I/O is implemented at the fifo layer using
* MSG_NBIO, so does not need to be forwarded down the stack.
*/
return (0);
case FIOASYNC:
case FIOSETOWN:
case FIOGETOWN:
/*
* These socket ioctls don't have any ordering requirements,
* so are called in an arbitrary order, and only on the
* sockets indicated by the file descriptor rights.
*
* XXXRW: If O_RDWR and the read socket accepts an ioctl but
* the write socket doesn't, the socketpair is left in an
* inconsistent state.
*/
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);
case FIONREAD:
/*
* FIONREAD will return 0 for non-readable descriptors, and
* the results of FIONREAD on the read socket for readable
* descriptors.
*/
if (!(fp->f_flag & FREAD)) {
*(int *)data = 0;
return (0);
}
filetmp.f_data = fi->fi_readsock;
filetmp.f_cred = cred;
return (soo_ioctl(&filetmp, com, data, cred, td));
default:
return (ENOTTY);
}
}
/*
* Because fifos are now a file descriptor layer object, EVFILT_VNODE is not
* implemented. Likely, fifo_kqfilter() should be removed, and
* fifo_kqfilter_f() should know how to forward the request to the underling
* vnode using f_vnode in the file descriptor here.
*/
static int
fifo_kqfilter_f(struct file *fp, struct knote *kn)
{
struct fifoinfo *fi;
struct socket *so;
struct sockbuf *sb;
fi = fp->f_data;
/*
* If a filter is requested that is not supported by this file
* descriptor, don't return an error, but also don't ever generate an
* event.
*/
if ((kn->kn_filter == EVFILT_READ) && !(fp->f_flag & FREAD)) {
kn->kn_fop = &fifo_notsup_filtops;
return (0);
}
if ((kn->kn_filter == EVFILT_WRITE) && !(fp->f_flag & FWRITE)) {
kn->kn_fop = &fifo_notsup_filtops;
return (0);
}
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 (EINVAL);
}
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 ((fp->f_flag & FREAD) && levents) {
filetmp.f_data = fip->fi_readsock;
filetmp.f_cred = cred;
mtx_lock(&fifo_mtx);
if (fp->f_seqcount == fip->fi_wgen)
levents |= POLLINIGNEOF;
mtx_unlock(&fifo_mtx);
revents |= soo_poll(&filetmp, levents, cred, td);
}
levents = events & (POLLOUT | POLLWRNORM | POLLWRBAND);
if ((fp->f_flag & FWRITE) && levents) {
filetmp.f_data = fip->fi_writesock;
filetmp.f_cred = cred;
revents |= soo_poll(&filetmp, levents, 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 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;
return (soreceive(fip->fi_readsock, NULL, uio, NULL, NULL, &sflags));
}
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_truncate_f(struct file *fp, off_t length, struct ucred *cred, struct thread *td)
{
return (vnops.fo_truncate(fp, length, 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 sflags;
fip = fp->f_data;
KASSERT(uio->uio_rw == UIO_WRITE,("fifo_write mode"));
sflags = (fp->f_flag & FNONBLOCK) ? MSG_NBIO : 0;
return (sosend(fip->fi_writesock, NULL, uio, 0, NULL, sflags, td));
}