freebsd-dev/sys/kern/subr_log.c

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/*
* Copyright (c) 1982, 1986, 1993
* The Regents of the University of California. 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. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 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.
*
* @(#)subr_log.c 8.1 (Berkeley) 6/10/93
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* $Id: subr_log.c,v 1.23 1997/09/14 02:46:44 peter Exp $
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*/
/*
* Error log buffer for kernel printf's.
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/conf.h>
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#include <sys/proc.h>
#include <sys/vnode.h>
#include <sys/filio.h>
#include <sys/ttycom.h>
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#include <sys/msgbuf.h>
#include <sys/fcntl.h>
#include <sys/signalvar.h>
#include <sys/kernel.h>
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#include <sys/poll.h>
#ifdef DEVFS
#include <sys/devfsext.h>
#endif /*DEVFS*/
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#define LOG_RDPRI (PZERO + 1)
#define LOG_ASYNC 0x04
#define LOG_RDWAIT 0x08
static d_open_t logopen;
static d_close_t logclose;
static d_read_t logread;
static d_ioctl_t logioctl;
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static d_poll_t logpoll;
#define CDEV_MAJOR 7
static struct cdevsw log_cdevsw =
{ logopen, logclose, logread, nowrite, /*7*/
logioctl, nostop, nullreset, nodevtotty,/* klog */
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logpoll, nommap, NULL, "log", NULL, -1 };
static struct logsoftc {
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int sc_state; /* see above for possibilities */
struct selinfo sc_selp; /* process waiting on select call */
int sc_pgid; /* process/group for async I/O */
} logsoftc;
int log_open; /* also used in log() */
/*ARGSUSED*/
static int
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logopen(dev, flags, mode, p)
dev_t dev;
int flags, mode;
struct proc *p;
{
if (log_open)
return (EBUSY);
log_open = 1;
logsoftc.sc_pgid = p->p_pid; /* signal process only */
return (0);
}
/*ARGSUSED*/
static int
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logclose(dev, flag, mode, p)
dev_t dev;
int flag, mode;
struct proc *p;
{
log_open = 0;
logsoftc.sc_state = 0;
return (0);
}
/*ARGSUSED*/
static int
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logread(dev, uio, flag)
dev_t dev;
struct uio *uio;
int flag;
{
register struct msgbuf *mbp = msgbufp;
register long l;
register int s;
int error = 0;
s = splhigh();
while (mbp->msg_bufr == mbp->msg_bufx) {
if (flag & IO_NDELAY) {
splx(s);
return (EWOULDBLOCK);
}
logsoftc.sc_state |= LOG_RDWAIT;
if ((error = tsleep((caddr_t)mbp, LOG_RDPRI | PCATCH,
"klog", 0))) {
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splx(s);
return (error);
}
}
splx(s);
logsoftc.sc_state &= ~LOG_RDWAIT;
while (uio->uio_resid > 0) {
l = mbp->msg_bufx - mbp->msg_bufr;
if (l < 0)
l = MSG_BSIZE - mbp->msg_bufr;
l = min(l, uio->uio_resid);
if (l == 0)
break;
error = uiomove((caddr_t)&mbp->msg_bufc[mbp->msg_bufr],
(int)l, uio);
if (error)
break;
mbp->msg_bufr += l;
if (mbp->msg_bufr >= MSG_BSIZE)
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mbp->msg_bufr = 0;
}
return (error);
}
/*ARGSUSED*/
static 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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int s;
int revents = 0;
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s = splhigh();
if (events & (POLLIN | POLLRDNORM))
if (msgbufp->msg_bufr != msgbufp->msg_bufx)
revents |= events & (POLLIN | POLLRDNORM);
else
selrecord(p, &logsoftc.sc_selp);
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splx(s);
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return (revents);
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}
void
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logwakeup()
{
struct proc *p;
if (!log_open)
return;
selwakeup(&logsoftc.sc_selp);
if (logsoftc.sc_state & LOG_ASYNC) {
if (logsoftc.sc_pgid < 0)
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gsignal(-logsoftc.sc_pgid, SIGIO);
else if ((p = pfind(logsoftc.sc_pgid)))
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psignal(p, SIGIO);
}
if (logsoftc.sc_state & LOG_RDWAIT) {
wakeup((caddr_t)msgbufp);
logsoftc.sc_state &= ~LOG_RDWAIT;
}
}
/*ARGSUSED*/
static int
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logioctl(dev, com, data, flag, p)
dev_t dev;
int com;
caddr_t data;
int flag;
struct proc *p;
{
long l;
int s;
switch (com) {
/* return number of characters immediately available */
case FIONREAD:
s = splhigh();
l = msgbufp->msg_bufx - msgbufp->msg_bufr;
splx(s);
if (l < 0)
l += MSG_BSIZE;
*(int *)data = l;
break;
case FIONBIO:
break;
case FIOASYNC:
if (*(int *)data)
logsoftc.sc_state |= LOG_ASYNC;
else
logsoftc.sc_state &= ~LOG_ASYNC;
break;
case TIOCSPGRP:
logsoftc.sc_pgid = *(int *)data;
break;
case TIOCGPGRP:
*(int *)data = logsoftc.sc_pgid;
break;
default:
return (ENOTTY);
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}
return (0);
}
static log_devsw_installed = 0;
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#ifdef DEVFS
static void *log_devfs_token;
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#endif
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static void log_drvinit __P((void *unused));
static void
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log_drvinit(unused)
void *unused;
{
dev_t dev;
if( ! log_devsw_installed ) {
dev = makedev(CDEV_MAJOR,0);
cdevsw_add(&dev,&log_cdevsw,NULL);
log_devsw_installed = 1;
#ifdef DEVFS
log_devfs_token = devfs_add_devswf(&log_cdevsw, 0, DV_CHR,
UID_ROOT, GID_WHEEL, 0600,
"klog");
#endif
}
}
SYSINIT(logdev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR,log_drvinit,NULL)