4787f91d6b
at the top of the minute, whichever comes first. It seems logtimeout() is only called once after the kernel log is opened and then never again after that. So I guess syslogd only gets kernel log messages by virtue of syncer(4)'s flushes ...? PR: 27361 Submitted by: pkern@utcc.utoronto.ca MFC after: 1 week
269 lines
6.6 KiB
C
269 lines
6.6 KiB
C
/*
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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 8.1 (Berkeley) 6/10/93
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* $FreeBSD$
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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/conf.h>
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#include <sys/proc.h>
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#include <sys/vnode.h>
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#include <sys/filio.h>
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#include <sys/ttycom.h>
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#include <sys/msgbuf.h>
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#include <sys/signalvar.h>
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#include <sys/kernel.h>
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#include <sys/poll.h>
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#include <sys/filedesc.h>
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#include <sys/sysctl.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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static d_open_t logopen;
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static d_close_t logclose;
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static d_read_t logread;
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static d_ioctl_t logioctl;
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static d_poll_t logpoll;
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static void logtimeout(void *arg);
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#define CDEV_MAJOR 7
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static struct cdevsw log_cdevsw = {
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/* open */ logopen,
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/* close */ logclose,
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/* read */ logread,
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/* write */ nowrite,
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/* ioctl */ logioctl,
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/* poll */ logpoll,
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/* mmap */ nommap,
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/* strategy */ nostrategy,
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/* name */ "log",
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/* maj */ CDEV_MAJOR,
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/* dump */ nodump,
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/* psize */ nopsize,
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/* flags */ 0,
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};
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static 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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struct sigio *sc_sigio; /* information for async I/O */
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struct callout sc_callout; /* callout to wakeup syslog */
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} logsoftc;
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int log_open; /* also used in log() */
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/* Times per second to check for a pending syslog wakeup. */
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static int log_wakeups_per_second = 5;
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SYSCTL_INT(_kern, OID_AUTO, log_wakeups_per_second, CTLFLAG_RW,
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&log_wakeups_per_second, 0, "");
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/*ARGSUSED*/
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static int
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logopen(dev_t dev, int flags, int mode, struct proc *p)
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{
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if (log_open)
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return (EBUSY);
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log_open = 1;
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callout_init(&logsoftc.sc_callout, 0);
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fsetown(p->p_pid, &logsoftc.sc_sigio); /* signal process only */
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callout_reset(&logsoftc.sc_callout, hz / log_wakeups_per_second,
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logtimeout, NULL);
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return (0);
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}
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/*ARGSUSED*/
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static int
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logclose(dev_t dev, int flag, int mode, struct proc *p)
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{
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log_open = 0;
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callout_stop(&logsoftc.sc_callout);
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logsoftc.sc_state = 0;
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funsetown(logsoftc.sc_sigio);
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return (0);
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}
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/*ARGSUSED*/
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static int
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logread(dev_t dev, struct uio *uio, int flag)
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{
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struct 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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if ((error = tsleep((caddr_t)mbp, LOG_RDPRI | PCATCH,
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"klog", 0))) {
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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_size - 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)msgbufp->msg_ptr + 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 >= mbp->msg_size)
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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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static int
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logpoll(dev_t dev, int events, struct proc *p)
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{
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int s;
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int revents = 0;
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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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static void
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logtimeout(void *arg)
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{
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if (!log_open)
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return;
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if (msgbuftrigger == 0) {
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callout_reset(&logsoftc.sc_callout,
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hz / log_wakeups_per_second, logtimeout, NULL);
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return;
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}
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msgbuftrigger = 0;
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selwakeup(&logsoftc.sc_selp);
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if ((logsoftc.sc_state & LOG_ASYNC) && logsoftc.sc_sigio != NULL)
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pgsigio(logsoftc.sc_sigio, SIGIO, 0);
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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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callout_reset(&logsoftc.sc_callout, hz / log_wakeups_per_second,
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logtimeout, NULL);
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}
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/*ARGSUSED*/
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static int
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logioctl(dev_t dev, u_long com, caddr_t data, int flag, 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_size;
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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 FIOSETOWN:
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return (fsetown(*(int *)data, &logsoftc.sc_sigio));
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case FIOGETOWN:
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*(int *)data = fgetown(logsoftc.sc_sigio);
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break;
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/* This is deprecated, FIOSETOWN should be used instead. */
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case TIOCSPGRP:
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return (fsetown(-(*(int *)data), &logsoftc.sc_sigio));
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/* This is deprecated, FIOGETOWN should be used instead */
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case TIOCGPGRP:
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*(int *)data = -fgetown(logsoftc.sc_sigio);
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break;
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default:
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return (ENOTTY);
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}
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return (0);
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}
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static void
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log_drvinit(void *unused)
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{
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make_dev(&log_cdevsw, 0, UID_ROOT, GID_WHEEL, 0600, "klog");
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}
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SYSINIT(logdev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR,log_drvinit,NULL)
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