7259ca3104
This gives the vfs layer a chance to provide handling for EVFILT_VNODE, for instance. Change pipe_specops to use the default vop_kqfilter to accommodate fifoops that don't specify the method (i.e. all in-tree). Based on a patch by Jan Kokemüller. PR: 225934 Reviewed by: kib, markj (both pre-KASSERT) Differential Revision: https://reviews.freebsd.org/D32271
382 lines
9.5 KiB
C
382 lines
9.5 KiB
C
/*-
|
|
* SPDX-License-Identifier: BSD-3-Clause
|
|
*
|
|
* Copyright (c) 1990, 1993, 1995
|
|
* The Regents of the University of California.
|
|
* Copyright (c) 2005 Robert N. M. Watson
|
|
* Copyright (c) 2012 Giovanni Trematerra
|
|
* 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 8.10 (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/selinfo.h>
|
|
#include <sys/pipe.h>
|
|
#include <sys/proc.h>
|
|
#include <sys/signalvar.h>
|
|
#include <sys/sx.h>
|
|
#include <sys/systm.h>
|
|
#include <sys/un.h>
|
|
#include <sys/unistd.h>
|
|
#include <sys/vnode.h>
|
|
|
|
/*
|
|
* This structure is associated with the FIFO vnode and stores
|
|
* the state associated with the FIFO.
|
|
* Notes about locking:
|
|
* - fi_pipe is invariant since init time.
|
|
* - fi_readers and fi_writers are protected by the vnode lock.
|
|
*/
|
|
struct fifoinfo {
|
|
struct pipe *fi_pipe;
|
|
long fi_readers;
|
|
long fi_writers;
|
|
u_int fi_rgen;
|
|
u_int fi_wgen;
|
|
};
|
|
|
|
static vop_print_t fifo_print;
|
|
static vop_open_t fifo_open;
|
|
static vop_close_t fifo_close;
|
|
static vop_advlock_t fifo_advlock;
|
|
|
|
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_link = VOP_PANIC,
|
|
.vop_mkdir = VOP_PANIC,
|
|
.vop_mknod = VOP_PANIC,
|
|
.vop_open = fifo_open,
|
|
.vop_pathconf = VOP_PANIC,
|
|
.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,
|
|
};
|
|
VFS_VOP_VECTOR_REGISTER(fifo_specops);
|
|
|
|
/*
|
|
* Dispose of fifo resources.
|
|
*/
|
|
static void
|
|
fifo_cleanup(struct vnode *vp)
|
|
{
|
|
struct fifoinfo *fip;
|
|
|
|
ASSERT_VOP_ELOCKED(vp, "fifo_cleanup");
|
|
fip = vp->v_fifoinfo;
|
|
if (fip->fi_readers == 0 && fip->fi_writers == 0) {
|
|
vp->v_fifoinfo = NULL;
|
|
pipe_dtor(fip->fi_pipe);
|
|
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;
|
|
struct file *fp;
|
|
struct thread *td;
|
|
struct fifoinfo *fip;
|
|
struct pipe *fpipe;
|
|
u_int gen;
|
|
int error, stops_deferred;
|
|
|
|
vp = ap->a_vp;
|
|
fp = ap->a_fp;
|
|
td = ap->a_td;
|
|
ASSERT_VOP_ELOCKED(vp, "fifo_open");
|
|
if (fp == NULL || (ap->a_mode & FEXEC) != 0)
|
|
return (EINVAL);
|
|
if ((fip = vp->v_fifoinfo) == NULL) {
|
|
error = pipe_named_ctor(&fpipe, td);
|
|
if (error != 0)
|
|
return (error);
|
|
fip = malloc(sizeof(*fip), M_VNODE, M_WAITOK | M_ZERO);
|
|
fip->fi_pipe = fpipe;
|
|
fpipe->pipe_wgen = 0;
|
|
KASSERT(vp->v_fifoinfo == NULL, ("fifo_open: v_fifoinfo race"));
|
|
vp->v_fifoinfo = fip;
|
|
}
|
|
fpipe = fip->fi_pipe;
|
|
KASSERT(fpipe != NULL, ("fifo_open: pipe is NULL"));
|
|
|
|
/*
|
|
* Use the pipe mutex here, in addition to the vnode lock,
|
|
* in order to allow vnode lock dropping before msleep() calls
|
|
* and still avoiding missed wakeups.
|
|
*/
|
|
PIPE_LOCK(fpipe);
|
|
if (ap->a_mode & FREAD) {
|
|
fip->fi_readers++;
|
|
fip->fi_rgen++;
|
|
if (fip->fi_readers == 1) {
|
|
fpipe->pipe_state &= ~PIPE_EOF;
|
|
if (fip->fi_writers > 0) {
|
|
wakeup(&fip->fi_writers);
|
|
pipeselwakeup(fpipe);
|
|
}
|
|
}
|
|
fp->f_pipegen = fpipe->pipe_wgen - fip->fi_writers;
|
|
}
|
|
if (ap->a_mode & FWRITE) {
|
|
if ((ap->a_mode & O_NONBLOCK) && fip->fi_readers == 0) {
|
|
PIPE_UNLOCK(fpipe);
|
|
if (fip->fi_writers == 0)
|
|
fifo_cleanup(vp);
|
|
return (ENXIO);
|
|
}
|
|
fip->fi_writers++;
|
|
fip->fi_wgen++;
|
|
if (fip->fi_writers == 1) {
|
|
fpipe->pipe_state &= ~PIPE_EOF;
|
|
if (fip->fi_readers > 0) {
|
|
wakeup(&fip->fi_readers);
|
|
pipeselwakeup(fpipe);
|
|
}
|
|
}
|
|
}
|
|
if ((ap->a_mode & O_NONBLOCK) == 0) {
|
|
if ((ap->a_mode & FREAD) && fip->fi_writers == 0) {
|
|
gen = fip->fi_wgen;
|
|
VOP_UNLOCK(vp);
|
|
stops_deferred = sigdeferstop(SIGDEFERSTOP_OFF);
|
|
error = msleep(&fip->fi_readers, PIPE_MTX(fpipe),
|
|
PDROP | PCATCH | PSOCK, "fifoor", 0);
|
|
sigallowstop(stops_deferred);
|
|
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
|
|
if (error != 0 && gen == fip->fi_wgen) {
|
|
fip->fi_readers--;
|
|
if (fip->fi_readers == 0) {
|
|
PIPE_LOCK(fpipe);
|
|
fpipe->pipe_state |= PIPE_EOF;
|
|
if (fpipe->pipe_state & PIPE_WANTW)
|
|
wakeup(fpipe);
|
|
pipeselwakeup(fpipe);
|
|
PIPE_UNLOCK(fpipe);
|
|
fifo_cleanup(vp);
|
|
}
|
|
return (error);
|
|
}
|
|
PIPE_LOCK(fpipe);
|
|
/*
|
|
* 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) {
|
|
gen = fip->fi_rgen;
|
|
VOP_UNLOCK(vp);
|
|
stops_deferred = sigdeferstop(SIGDEFERSTOP_OFF);
|
|
error = msleep(&fip->fi_writers, PIPE_MTX(fpipe),
|
|
PDROP | PCATCH | PSOCK, "fifoow", 0);
|
|
sigallowstop(stops_deferred);
|
|
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
|
|
if (error != 0 && gen == fip->fi_rgen) {
|
|
fip->fi_writers--;
|
|
if (fip->fi_writers == 0) {
|
|
PIPE_LOCK(fpipe);
|
|
fpipe->pipe_state |= PIPE_EOF;
|
|
if (fpipe->pipe_state & PIPE_WANTR)
|
|
wakeup(fpipe);
|
|
fpipe->pipe_wgen++;
|
|
pipeselwakeup(fpipe);
|
|
PIPE_UNLOCK(fpipe);
|
|
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.
|
|
*/
|
|
PIPE_LOCK(fpipe);
|
|
}
|
|
}
|
|
PIPE_UNLOCK(fpipe);
|
|
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, fpipe, &pipeops);
|
|
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;
|
|
struct fifoinfo *fip;
|
|
struct pipe *cpipe;
|
|
|
|
vp = ap->a_vp;
|
|
ASSERT_VOP_ELOCKED(vp, "fifo_close");
|
|
fip = vp->v_fifoinfo;
|
|
|
|
/*
|
|
* During open, it is possible that the fifo vnode is relocked
|
|
* after the vnode is instantiated but before VOP_OPEN() is
|
|
* done. For instance, vn_open_vnode() might need to upgrade
|
|
* vnode lock, or ffs_vput_pair() needs to unlock vp to sync
|
|
* dvp. In this case, reclaim can observe us with v_fifoinfo
|
|
* equal to NULL.
|
|
*/
|
|
if (fip == NULL)
|
|
return (0);
|
|
|
|
cpipe = fip->fi_pipe;
|
|
if (ap->a_fflag & FREAD) {
|
|
fip->fi_readers--;
|
|
if (fip->fi_readers == 0) {
|
|
PIPE_LOCK(cpipe);
|
|
cpipe->pipe_state |= PIPE_EOF;
|
|
if ((cpipe->pipe_state & PIPE_WANTW)) {
|
|
cpipe->pipe_state &= ~PIPE_WANTW;
|
|
wakeup(cpipe);
|
|
}
|
|
pipeselwakeup(cpipe);
|
|
PIPE_UNLOCK(cpipe);
|
|
}
|
|
}
|
|
if (ap->a_fflag & FWRITE) {
|
|
fip->fi_writers--;
|
|
if (fip->fi_writers == 0) {
|
|
PIPE_LOCK(cpipe);
|
|
cpipe->pipe_state |= PIPE_EOF;
|
|
if ((cpipe->pipe_state & PIPE_WANTR)) {
|
|
cpipe->pipe_state &= ~PIPE_WANTR;
|
|
wakeup(cpipe);
|
|
}
|
|
cpipe->pipe_wgen++;
|
|
pipeselwakeup(cpipe);
|
|
PIPE_UNLOCK(cpipe);
|
|
}
|
|
}
|
|
fifo_cleanup(vp);
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* Print out internal contents of a fifo vnode.
|
|
*/
|
|
int
|
|
fifo_printinfo(vp)
|
|
struct vnode *vp;
|
|
{
|
|
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);
|
|
}
|
|
|
|
/*
|
|
* 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;
|
|
{
|
|
|
|
if ((ap->a_flags & F_FLOCK) == 0)
|
|
return (EINVAL);
|
|
return (vop_stdadvlock(ap));
|
|
}
|