51369649b0
Mainly focus on files that use BSD 3-Clause license. The Software Package Data Exchange (SPDX) group provides a specification to make it easier for automated tools to detect and summarize well known opensource licenses. We are gradually adopting the specification, noting that the tags are considered only advisory and do not, in any way, superceed or replace the license texts. Special thanks to Wind River for providing access to "The Duke of Highlander" tool: an older (2014) run over FreeBSD tree was useful as a starting point.
361 lines
9.0 KiB
C
361 lines
9.0 KiB
C
/*-
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* SPDX-License-Identifier: BSD-3-Clause
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*
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* Copyright (c) 1990, 1993, 1995
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* The Regents of the University of California.
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* Copyright (c) 2005 Robert N. M. Watson
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* Copyright (c) 2012 Giovanni Trematerra
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @(#)fifo_vnops.c 8.10 (Berkeley) 5/27/95
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* $FreeBSD$
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*/
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#include <sys/param.h>
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#include <sys/event.h>
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#include <sys/file.h>
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#include <sys/filedesc.h>
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#include <sys/filio.h>
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#include <sys/fcntl.h>
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#include <sys/kernel.h>
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#include <sys/lock.h>
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#include <sys/mutex.h>
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#include <sys/malloc.h>
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#include <sys/selinfo.h>
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#include <sys/pipe.h>
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#include <sys/proc.h>
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#include <sys/signalvar.h>
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#include <sys/sx.h>
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#include <sys/systm.h>
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#include <sys/un.h>
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#include <sys/unistd.h>
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#include <sys/vnode.h>
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/*
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* This structure is associated with the FIFO vnode and stores
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* the state associated with the FIFO.
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* Notes about locking:
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* - fi_pipe is invariant since init time.
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* - fi_readers and fi_writers are protected by the vnode lock.
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*/
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struct fifoinfo {
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struct pipe *fi_pipe;
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long fi_readers;
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long fi_writers;
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u_int fi_rgen;
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u_int fi_wgen;
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};
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static vop_print_t fifo_print;
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static vop_open_t fifo_open;
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static vop_close_t fifo_close;
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static vop_advlock_t fifo_advlock;
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struct vop_vector fifo_specops = {
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.vop_default = &default_vnodeops,
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.vop_advlock = fifo_advlock,
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.vop_close = fifo_close,
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.vop_create = VOP_PANIC,
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.vop_getattr = VOP_EBADF,
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.vop_ioctl = VOP_PANIC,
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.vop_kqfilter = VOP_PANIC,
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.vop_link = VOP_PANIC,
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.vop_mkdir = VOP_PANIC,
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.vop_mknod = VOP_PANIC,
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.vop_open = fifo_open,
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.vop_pathconf = vop_stdpathconf,
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.vop_print = fifo_print,
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.vop_read = VOP_PANIC,
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.vop_readdir = VOP_PANIC,
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.vop_readlink = VOP_PANIC,
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.vop_reallocblks = VOP_PANIC,
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.vop_reclaim = VOP_NULL,
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.vop_remove = VOP_PANIC,
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.vop_rename = VOP_PANIC,
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.vop_rmdir = VOP_PANIC,
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.vop_setattr = VOP_EBADF,
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.vop_symlink = VOP_PANIC,
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.vop_write = VOP_PANIC,
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};
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/*
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* Dispose of fifo resources.
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*/
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static void
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fifo_cleanup(struct vnode *vp)
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{
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struct fifoinfo *fip;
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ASSERT_VOP_ELOCKED(vp, "fifo_cleanup");
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fip = vp->v_fifoinfo;
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if (fip->fi_readers == 0 && fip->fi_writers == 0) {
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vp->v_fifoinfo = NULL;
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pipe_dtor(fip->fi_pipe);
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free(fip, M_VNODE);
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}
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}
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/*
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* Open called to set up a new instance of a fifo or
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* to find an active instance of a fifo.
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*/
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/* ARGSUSED */
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static int
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fifo_open(ap)
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struct vop_open_args /* {
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struct vnode *a_vp;
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int a_mode;
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struct ucred *a_cred;
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struct thread *a_td;
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struct file *a_fp;
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} */ *ap;
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{
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struct vnode *vp;
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struct file *fp;
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struct thread *td;
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struct fifoinfo *fip;
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struct pipe *fpipe;
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u_int gen;
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int error, stops_deferred;
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vp = ap->a_vp;
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fp = ap->a_fp;
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td = ap->a_td;
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ASSERT_VOP_ELOCKED(vp, "fifo_open");
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if (fp == NULL || (ap->a_mode & FEXEC) != 0)
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return (EINVAL);
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if ((fip = vp->v_fifoinfo) == NULL) {
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pipe_named_ctor(&fpipe, td);
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fip = malloc(sizeof(*fip), M_VNODE, M_WAITOK);
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fip->fi_pipe = fpipe;
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fpipe->pipe_wgen = fip->fi_readers = fip->fi_writers = 0;
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KASSERT(vp->v_fifoinfo == NULL, ("fifo_open: v_fifoinfo race"));
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vp->v_fifoinfo = fip;
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}
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fpipe = fip->fi_pipe;
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KASSERT(fpipe != NULL, ("fifo_open: pipe is NULL"));
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/*
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* Use the pipe mutex here, in addition to the vnode lock,
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* in order to allow vnode lock dropping before msleep() calls
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* and still avoiding missed wakeups.
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*/
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PIPE_LOCK(fpipe);
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if (ap->a_mode & FREAD) {
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fip->fi_readers++;
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fip->fi_rgen++;
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if (fip->fi_readers == 1) {
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fpipe->pipe_state &= ~PIPE_EOF;
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if (fip->fi_writers > 0)
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wakeup(&fip->fi_writers);
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}
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fp->f_seqcount = fpipe->pipe_wgen - fip->fi_writers;
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}
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if (ap->a_mode & FWRITE) {
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if ((ap->a_mode & O_NONBLOCK) && fip->fi_readers == 0) {
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PIPE_UNLOCK(fpipe);
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if (fip->fi_writers == 0)
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fifo_cleanup(vp);
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return (ENXIO);
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}
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fip->fi_writers++;
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fip->fi_wgen++;
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if (fip->fi_writers == 1) {
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fpipe->pipe_state &= ~PIPE_EOF;
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if (fip->fi_readers > 0)
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wakeup(&fip->fi_readers);
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}
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}
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if ((ap->a_mode & O_NONBLOCK) == 0) {
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if ((ap->a_mode & FREAD) && fip->fi_writers == 0) {
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gen = fip->fi_wgen;
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VOP_UNLOCK(vp, 0);
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stops_deferred = sigdeferstop(SIGDEFERSTOP_OFF);
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error = msleep(&fip->fi_readers, PIPE_MTX(fpipe),
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PDROP | PCATCH | PSOCK, "fifoor", 0);
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sigallowstop(stops_deferred);
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vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
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if (error != 0 && gen == fip->fi_wgen) {
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fip->fi_readers--;
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if (fip->fi_readers == 0) {
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PIPE_LOCK(fpipe);
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fpipe->pipe_state |= PIPE_EOF;
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if (fpipe->pipe_state & PIPE_WANTW)
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wakeup(fpipe);
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PIPE_UNLOCK(fpipe);
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fifo_cleanup(vp);
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}
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return (error);
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}
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PIPE_LOCK(fpipe);
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/*
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* We must have got woken up because we had a writer.
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* That (and not still having one) is the condition
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* that we must wait for.
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*/
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}
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if ((ap->a_mode & FWRITE) && fip->fi_readers == 0) {
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gen = fip->fi_rgen;
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VOP_UNLOCK(vp, 0);
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stops_deferred = sigdeferstop(SIGDEFERSTOP_OFF);
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error = msleep(&fip->fi_writers, PIPE_MTX(fpipe),
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PDROP | PCATCH | PSOCK, "fifoow", 0);
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sigallowstop(stops_deferred);
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vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
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if (error != 0 && gen == fip->fi_rgen) {
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fip->fi_writers--;
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if (fip->fi_writers == 0) {
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PIPE_LOCK(fpipe);
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fpipe->pipe_state |= PIPE_EOF;
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if (fpipe->pipe_state & PIPE_WANTR)
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wakeup(fpipe);
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fpipe->pipe_wgen++;
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PIPE_UNLOCK(fpipe);
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fifo_cleanup(vp);
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}
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return (error);
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}
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/*
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* We must have got woken up because we had
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* a reader. That (and not still having one)
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* is the condition that we must wait for.
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*/
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PIPE_LOCK(fpipe);
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}
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}
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PIPE_UNLOCK(fpipe);
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KASSERT(fp != NULL, ("can't fifo/vnode bypass"));
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KASSERT(fp->f_ops == &badfileops, ("not badfileops in fifo_open"));
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finit(fp, fp->f_flag, DTYPE_FIFO, fpipe, &pipeops);
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return (0);
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}
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/*
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* Device close routine
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*/
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/* ARGSUSED */
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static int
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fifo_close(ap)
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struct vop_close_args /* {
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struct vnode *a_vp;
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int a_fflag;
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struct ucred *a_cred;
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struct thread *a_td;
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} */ *ap;
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{
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struct vnode *vp;
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struct fifoinfo *fip;
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struct pipe *cpipe;
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vp = ap->a_vp;
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fip = vp->v_fifoinfo;
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cpipe = fip->fi_pipe;
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ASSERT_VOP_ELOCKED(vp, "fifo_close");
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if (ap->a_fflag & FREAD) {
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fip->fi_readers--;
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if (fip->fi_readers == 0) {
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PIPE_LOCK(cpipe);
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cpipe->pipe_state |= PIPE_EOF;
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if ((cpipe->pipe_state & PIPE_WANTW)) {
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cpipe->pipe_state &= ~PIPE_WANTW;
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wakeup(cpipe);
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}
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pipeselwakeup(cpipe);
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PIPE_UNLOCK(cpipe);
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}
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}
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if (ap->a_fflag & FWRITE) {
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fip->fi_writers--;
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if (fip->fi_writers == 0) {
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PIPE_LOCK(cpipe);
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cpipe->pipe_state |= PIPE_EOF;
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if ((cpipe->pipe_state & PIPE_WANTR)) {
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cpipe->pipe_state &= ~PIPE_WANTR;
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wakeup(cpipe);
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}
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cpipe->pipe_wgen++;
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pipeselwakeup(cpipe);
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PIPE_UNLOCK(cpipe);
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}
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}
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fifo_cleanup(vp);
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return (0);
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}
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/*
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* Print out internal contents of a fifo vnode.
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*/
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int
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fifo_printinfo(vp)
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struct vnode *vp;
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{
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struct fifoinfo *fip = vp->v_fifoinfo;
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if (fip == NULL){
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printf(", NULL v_fifoinfo");
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return (0);
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}
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printf(", fifo with %ld readers and %ld writers",
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fip->fi_readers, fip->fi_writers);
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return (0);
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}
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/*
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* Print out the contents of a fifo vnode.
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*/
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static int
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fifo_print(ap)
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struct vop_print_args /* {
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struct vnode *a_vp;
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} */ *ap;
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{
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printf(" ");
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fifo_printinfo(ap->a_vp);
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printf("\n");
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return (0);
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}
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/*
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* Fifo advisory byte-level locks.
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*/
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/* ARGSUSED */
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static int
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fifo_advlock(ap)
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struct vop_advlock_args /* {
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struct vnode *a_vp;
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caddr_t a_id;
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int a_op;
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struct flock *a_fl;
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int a_flags;
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} */ *ap;
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{
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return (ap->a_flags & F_FLOCK ? EOPNOTSUPP : EINVAL);
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}
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