NetBSD/sys/kern/subr_log.c
jdolecek e0cc03a09b merge kqueue branch into -current
kqueue provides a stateful and efficient event notification framework
currently supported events include socket, file, directory, fifo,
pipe, tty and device changes, and monitoring of processes and signals

kqueue is supported by all writable filesystems in NetBSD tree
(with exception of Coda) and all device drivers supporting poll(2)

based on work done by Jonathan Lemon for FreeBSD
initial NetBSD port done by Luke Mewburn and Jason Thorpe
2002-10-23 09:10:23 +00:00

349 lines
7.8 KiB
C

/* $NetBSD: subr_log.c,v 1.24 2002/10/23 09:14:22 jdolecek 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/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: subr_log.c,v 1.24 2002/10/23 09:14:22 jdolecek Exp $");
#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. */
dev_type_open(logopen);
dev_type_close(logclose);
dev_type_read(logread);
dev_type_ioctl(logioctl);
dev_type_poll(logpoll);
dev_type_kqfilter(logkqfilter);
const struct cdevsw log_cdevsw = {
logopen, logclose, logread, nowrite, logioctl,
nostop, notty, logpoll, nommap, logkqfilter,
};
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);
}
static void
filt_logrdetach(struct knote *kn)
{
int s;
s = splhigh();
SLIST_REMOVE(&logsoftc.sc_selp.si_klist, kn, knote, kn_selnext);
splx(s);
}
static int
filt_logread(struct knote *kn, long hint)
{
if (msgbufp->msg_bufr == msgbufp->msg_bufx)
return (0);
if (msgbufp->msg_bufr < msgbufp->msg_bufx)
kn->kn_data = msgbufp->msg_bufx - msgbufp->msg_bufr;
else
kn->kn_data = (msgbufp->msg_bufs - msgbufp->msg_bufr) +
msgbufp->msg_bufx;
return (1);
}
static const struct filterops logread_filtops =
{ 1, NULL, filt_logrdetach, filt_logread };
int
logkqfilter(dev_t dev, struct knote *kn)
{
struct klist *klist;
int s;
switch (kn->kn_filter) {
case EVFILT_READ:
klist = &logsoftc.sc_selp.si_klist;
kn->kn_fop = &logread_filtops;
break;
default:
return (1);
}
kn->kn_hook = NULL;
s = splhigh();
SLIST_INSERT_HEAD(klist, kn, kn_selnext);
splx(s);
return (0);
}
void
logwakeup()
{
struct proc *p;
if (!log_open)
return;
selnotify(&logsoftc.sc_selp, 0);
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 (EPASSTHROUGH);
}
return (0);
}