280 lines
6.5 KiB
C
280 lines
6.5 KiB
C
/* $NetBSD: subr_log.c,v 1.20 2000/05/28 18:31:13 jhawk Exp $ */
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/*
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* Copyright (c) 1982, 1986, 1993
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* The Regents of the University of California. 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. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. 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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* @(#)subr_log.c 8.3 (Berkeley) 2/14/95
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*/
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/*
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* Error log buffer for kernel printf's.
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*/
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/proc.h>
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#include <sys/vnode.h>
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#include <sys/ioctl.h>
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#include <sys/msgbuf.h>
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#include <sys/file.h>
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#include <sys/signalvar.h>
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#include <sys/syslog.h>
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#include <sys/conf.h>
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#include <sys/select.h>
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#include <sys/poll.h>
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#define LOG_RDPRI (PZERO + 1)
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#define LOG_ASYNC 0x04
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#define LOG_RDWAIT 0x08
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struct logsoftc {
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int sc_state; /* see above for possibilities */
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struct selinfo sc_selp; /* process waiting on select call */
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int sc_pgid; /* process/group for async I/O */
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} logsoftc;
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int log_open; /* also used in log() */
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int msgbufmapped; /* is the message buffer mapped */
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int msgbufenabled; /* is logging to the buffer enabled */
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struct kern_msgbuf *msgbufp; /* the mapped buffer, itself. */
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void
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initmsgbuf(buf, bufsize)
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caddr_t buf;
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size_t bufsize;
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{
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struct kern_msgbuf *mbp;
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long new_bufs;
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/* Sanity-check the given size. */
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if (bufsize < sizeof(struct kern_msgbuf))
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return;
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mbp = msgbufp = (struct kern_msgbuf *)buf;
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new_bufs = bufsize - offsetof(struct kern_msgbuf, msg_bufc);
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if ((mbp->msg_magic != MSG_MAGIC) || (mbp->msg_bufs != new_bufs) ||
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(mbp->msg_bufr < 0) || (mbp->msg_bufr >= mbp->msg_bufs) ||
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(mbp->msg_bufx < 0) || (mbp->msg_bufx >= mbp->msg_bufs)) {
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/*
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* If the buffer magic number is wrong, has changed
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* size (which shouldn't happen often), or is
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* internally inconsistent, initialize it.
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*/
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memset(buf, 0, bufsize);
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mbp->msg_magic = MSG_MAGIC;
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mbp->msg_bufs = new_bufs;
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}
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/* mark it as ready for use. */
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msgbufmapped = msgbufenabled = 1;
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}
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/*ARGSUSED*/
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int
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logopen(dev, flags, mode, p)
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dev_t dev;
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int flags, mode;
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struct proc *p;
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{
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struct kern_msgbuf *mbp = msgbufp;
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if (log_open)
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return (EBUSY);
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log_open = 1;
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logsoftc.sc_pgid = p->p_pid; /* signal process only */
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/*
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* The message buffer is initialized during system configuration.
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* If it's been clobbered, note that and return an error. (This
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* allows a user to potentially read the buffer via /dev/kmem,
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* and try to figure out what clobbered it.
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*/
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if (mbp->msg_magic != MSG_MAGIC) {
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msgbufenabled = 0;
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return (ENXIO);
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}
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return (0);
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}
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/*ARGSUSED*/
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int
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logclose(dev, flag, mode, p)
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dev_t dev;
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int flag, mode;
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struct proc *p;
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{
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log_open = 0;
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logsoftc.sc_state = 0;
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return (0);
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}
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/*ARGSUSED*/
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int
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logread(dev, uio, flag)
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dev_t dev;
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struct uio *uio;
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int flag;
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{
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struct kern_msgbuf *mbp = msgbufp;
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long l;
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int s;
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int error = 0;
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s = splhigh();
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while (mbp->msg_bufr == mbp->msg_bufx) {
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if (flag & IO_NDELAY) {
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splx(s);
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return (EWOULDBLOCK);
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}
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logsoftc.sc_state |= LOG_RDWAIT;
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error = tsleep((caddr_t)mbp, LOG_RDPRI | PCATCH,
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"klog", 0);
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if (error) {
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splx(s);
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return (error);
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}
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}
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splx(s);
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logsoftc.sc_state &= ~LOG_RDWAIT;
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while (uio->uio_resid > 0) {
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l = mbp->msg_bufx - mbp->msg_bufr;
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if (l < 0)
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l = mbp->msg_bufs - mbp->msg_bufr;
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l = min(l, uio->uio_resid);
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if (l == 0)
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break;
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error = uiomove((caddr_t)&mbp->msg_bufc[mbp->msg_bufr],
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(int)l, uio);
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if (error)
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break;
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mbp->msg_bufr += l;
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if (mbp->msg_bufr < 0 || mbp->msg_bufr >= mbp->msg_bufs)
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mbp->msg_bufr = 0;
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}
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return (error);
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}
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/*ARGSUSED*/
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int
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logpoll(dev, events, p)
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dev_t dev;
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int events;
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struct proc *p;
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{
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int revents = 0;
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int s = splhigh();
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if (events & (POLLIN | POLLRDNORM)) {
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if (msgbufp->msg_bufr != msgbufp->msg_bufx)
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revents |= events & (POLLIN | POLLRDNORM);
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else
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selrecord(p, &logsoftc.sc_selp);
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}
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splx(s);
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return (revents);
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}
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void
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logwakeup()
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{
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struct proc *p;
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if (!log_open)
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return;
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selwakeup(&logsoftc.sc_selp);
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if (logsoftc.sc_state & LOG_ASYNC) {
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if (logsoftc.sc_pgid < 0)
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gsignal(-logsoftc.sc_pgid, SIGIO);
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else if (logsoftc.sc_pgid > 0 &&
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(p = pfind(logsoftc.sc_pgid)) != NULL)
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psignal(p, SIGIO);
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}
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if (logsoftc.sc_state & LOG_RDWAIT) {
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wakeup((caddr_t)msgbufp);
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logsoftc.sc_state &= ~LOG_RDWAIT;
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}
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}
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/*ARGSUSED*/
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int
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logioctl(dev, com, data, flag, p)
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dev_t dev;
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u_long com;
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caddr_t data;
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int flag;
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struct proc *p;
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{
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long l;
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int s;
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switch (com) {
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/* return number of characters immediately available */
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case FIONREAD:
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s = splhigh();
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l = msgbufp->msg_bufx - msgbufp->msg_bufr;
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splx(s);
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if (l < 0)
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l += msgbufp->msg_bufs;
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*(int *)data = l;
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break;
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case FIONBIO:
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break;
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case FIOASYNC:
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if (*(int *)data)
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logsoftc.sc_state |= LOG_ASYNC;
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else
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logsoftc.sc_state &= ~LOG_ASYNC;
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break;
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case TIOCSPGRP:
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logsoftc.sc_pgid = *(int *)data;
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break;
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case TIOCGPGRP:
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*(int *)data = logsoftc.sc_pgid;
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break;
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default:
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return (-1);
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}
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return (0);
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}
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