NetBSD/sys/kern/subr_log.c

280 lines
6.5 KiB
C

/* $NetBSD: subr_log.c,v 1.20 2000/05/28 18:31:13 jhawk Exp $ */
/*
* 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 8.3 (Berkeley) 2/14/95
*/
/*
* Error log buffer for kernel printf's.
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/vnode.h>
#include <sys/ioctl.h>
#include <sys/msgbuf.h>
#include <sys/file.h>
#include <sys/signalvar.h>
#include <sys/syslog.h>
#include <sys/conf.h>
#include <sys/select.h>
#include <sys/poll.h>
#define LOG_RDPRI (PZERO + 1)
#define LOG_ASYNC 0x04
#define LOG_RDWAIT 0x08
struct logsoftc {
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() */
int msgbufmapped; /* is the message buffer mapped */
int msgbufenabled; /* is logging to the buffer enabled */
struct kern_msgbuf *msgbufp; /* the mapped buffer, itself. */
void
initmsgbuf(buf, bufsize)
caddr_t buf;
size_t bufsize;
{
struct kern_msgbuf *mbp;
long new_bufs;
/* Sanity-check the given size. */
if (bufsize < sizeof(struct kern_msgbuf))
return;
mbp = msgbufp = (struct kern_msgbuf *)buf;
new_bufs = bufsize - offsetof(struct kern_msgbuf, msg_bufc);
if ((mbp->msg_magic != MSG_MAGIC) || (mbp->msg_bufs != new_bufs) ||
(mbp->msg_bufr < 0) || (mbp->msg_bufr >= mbp->msg_bufs) ||
(mbp->msg_bufx < 0) || (mbp->msg_bufx >= mbp->msg_bufs)) {
/*
* If the buffer magic number is wrong, has changed
* size (which shouldn't happen often), or is
* internally inconsistent, initialize it.
*/
memset(buf, 0, bufsize);
mbp->msg_magic = MSG_MAGIC;
mbp->msg_bufs = new_bufs;
}
/* mark it as ready for use. */
msgbufmapped = msgbufenabled = 1;
}
/*ARGSUSED*/
int
logopen(dev, flags, mode, p)
dev_t dev;
int flags, mode;
struct proc *p;
{
struct kern_msgbuf *mbp = msgbufp;
if (log_open)
return (EBUSY);
log_open = 1;
logsoftc.sc_pgid = p->p_pid; /* signal process only */
/*
* The message buffer is initialized during system configuration.
* If it's been clobbered, note that and return an error. (This
* allows a user to potentially read the buffer via /dev/kmem,
* and try to figure out what clobbered it.
*/
if (mbp->msg_magic != MSG_MAGIC) {
msgbufenabled = 0;
return (ENXIO);
}
return (0);
}
/*ARGSUSED*/
int
logclose(dev, flag, mode, p)
dev_t dev;
int flag, mode;
struct proc *p;
{
log_open = 0;
logsoftc.sc_state = 0;
return (0);
}
/*ARGSUSED*/
int
logread(dev, uio, flag)
dev_t dev;
struct uio *uio;
int flag;
{
struct kern_msgbuf *mbp = msgbufp;
long l;
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;
error = tsleep((caddr_t)mbp, LOG_RDPRI | PCATCH,
"klog", 0);
if (error) {
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 = mbp->msg_bufs - 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 < 0 || mbp->msg_bufr >= mbp->msg_bufs)
mbp->msg_bufr = 0;
}
return (error);
}
/*ARGSUSED*/
int
logpoll(dev, events, p)
dev_t dev;
int events;
struct proc *p;
{
int revents = 0;
int s = splhigh();
if (events & (POLLIN | POLLRDNORM)) {
if (msgbufp->msg_bufr != msgbufp->msg_bufx)
revents |= events & (POLLIN | POLLRDNORM);
else
selrecord(p, &logsoftc.sc_selp);
}
splx(s);
return (revents);
}
void
logwakeup()
{
struct proc *p;
if (!log_open)
return;
selwakeup(&logsoftc.sc_selp);
if (logsoftc.sc_state & LOG_ASYNC) {
if (logsoftc.sc_pgid < 0)
gsignal(-logsoftc.sc_pgid, SIGIO);
else if (logsoftc.sc_pgid > 0 &&
(p = pfind(logsoftc.sc_pgid)) != NULL)
psignal(p, SIGIO);
}
if (logsoftc.sc_state & LOG_RDWAIT) {
wakeup((caddr_t)msgbufp);
logsoftc.sc_state &= ~LOG_RDWAIT;
}
}
/*ARGSUSED*/
int
logioctl(dev, com, data, flag, p)
dev_t dev;
u_long 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 += msgbufp->msg_bufs;
*(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 (-1);
}
return (0);
}