544 lines
13 KiB
C
544 lines
13 KiB
C
/* $NetBSD: subr_log.c,v 1.60 2020/12/11 03:00:09 thorpej Exp $ */
|
|
|
|
/*-
|
|
* Copyright (c) 2007, 2008 The NetBSD Foundation, Inc.
|
|
* All rights reserved.
|
|
*
|
|
* This code is derived from software contributed to The NetBSD Foundation
|
|
* by Andrew Doran.
|
|
*
|
|
* 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.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
|
|
*/
|
|
|
|
/*
|
|
* 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. 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 1.60 2020/12/11 03:00:09 thorpej Exp $");
|
|
|
|
#include <sys/param.h>
|
|
#include <sys/systm.h>
|
|
#include <sys/kernel.h>
|
|
#include <sys/proc.h>
|
|
#include <sys/vnode.h>
|
|
#include <sys/ioctl.h>
|
|
#include <sys/msgbuf.h>
|
|
#include <sys/file.h>
|
|
#include <sys/syslog.h>
|
|
#include <sys/conf.h>
|
|
#include <sys/select.h>
|
|
#include <sys/poll.h>
|
|
#include <sys/intr.h>
|
|
#include <sys/sysctl.h>
|
|
#include <sys/ktrace.h>
|
|
|
|
static int sysctl_msgbuf(SYSCTLFN_PROTO);
|
|
|
|
static void logsoftintr(void *);
|
|
|
|
static bool log_async;
|
|
static struct selinfo log_selp; /* process waiting on select call */
|
|
static pid_t log_pgid; /* process/group for async I/O */
|
|
static kcondvar_t log_cv;
|
|
static void *log_sih;
|
|
|
|
kmutex_t log_lock;
|
|
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(void *bf, 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 *)bf;
|
|
|
|
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(bf, 0, bufsize);
|
|
mbp->msg_magic = MSG_MAGIC;
|
|
mbp->msg_bufs = new_bufs;
|
|
}
|
|
|
|
/* mark it as ready for use. */
|
|
msgbufmapped = msgbufenabled = 1;
|
|
}
|
|
|
|
void
|
|
loginit(void)
|
|
{
|
|
|
|
mutex_init(&log_lock, MUTEX_DEFAULT, IPL_VM);
|
|
selinit(&log_selp);
|
|
cv_init(&log_cv, "klog");
|
|
log_sih = softint_establish(SOFTINT_CLOCK | SOFTINT_MPSAFE,
|
|
logsoftintr, NULL);
|
|
|
|
sysctl_createv(NULL, 0, NULL, NULL,
|
|
CTLFLAG_PERMANENT,
|
|
CTLTYPE_INT, "msgbufsize",
|
|
SYSCTL_DESCR("Size of the kernel message buffer"),
|
|
sysctl_msgbuf, 0, NULL, 0,
|
|
CTL_KERN, KERN_MSGBUFSIZE, CTL_EOL);
|
|
sysctl_createv(NULL, 0, NULL, NULL,
|
|
CTLFLAG_PERMANENT,
|
|
CTLTYPE_INT, "msgbuf",
|
|
SYSCTL_DESCR("Kernel message buffer"),
|
|
sysctl_msgbuf, 0, NULL, 0,
|
|
CTL_KERN, KERN_MSGBUF, CTL_EOL);
|
|
}
|
|
|
|
/*ARGSUSED*/
|
|
static int
|
|
logopen(dev_t dev, int flags, int mode, struct lwp *l)
|
|
{
|
|
struct kern_msgbuf *mbp = msgbufp;
|
|
int error = 0;
|
|
|
|
mutex_spin_enter(&log_lock);
|
|
if (log_open) {
|
|
error = EBUSY;
|
|
} else {
|
|
log_open = 1;
|
|
log_pgid = l->l_proc->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 read
|
|
* the buffer via /dev/kmem, and try to figure out
|
|
* what clobbered it.
|
|
*/
|
|
if (mbp->msg_magic != MSG_MAGIC) {
|
|
msgbufenabled = 0;
|
|
error = ENXIO;
|
|
}
|
|
}
|
|
mutex_spin_exit(&log_lock);
|
|
|
|
return error;
|
|
}
|
|
|
|
/*ARGSUSED*/
|
|
static int
|
|
logclose(dev_t dev, int flag, int mode, struct lwp *l)
|
|
{
|
|
|
|
mutex_spin_enter(&log_lock);
|
|
log_pgid = 0;
|
|
log_open = 0;
|
|
log_async = 0;
|
|
mutex_spin_exit(&log_lock);
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*ARGSUSED*/
|
|
static int
|
|
logread(dev_t dev, struct uio *uio, int flag)
|
|
{
|
|
struct kern_msgbuf *mbp = msgbufp;
|
|
long l;
|
|
int error = 0;
|
|
|
|
mutex_spin_enter(&log_lock);
|
|
while (mbp->msg_bufr == mbp->msg_bufx) {
|
|
if (flag & IO_NDELAY) {
|
|
mutex_spin_exit(&log_lock);
|
|
return EWOULDBLOCK;
|
|
}
|
|
error = cv_wait_sig(&log_cv, &log_lock);
|
|
if (error) {
|
|
mutex_spin_exit(&log_lock);
|
|
return error;
|
|
}
|
|
}
|
|
while (uio->uio_resid > 0) {
|
|
l = mbp->msg_bufx - mbp->msg_bufr;
|
|
if (l < 0)
|
|
l = mbp->msg_bufs - mbp->msg_bufr;
|
|
l = uimin(l, uio->uio_resid);
|
|
if (l == 0)
|
|
break;
|
|
mutex_spin_exit(&log_lock);
|
|
error = uiomove(&mbp->msg_bufc[mbp->msg_bufr], (int)l, uio);
|
|
mutex_spin_enter(&log_lock);
|
|
if (error)
|
|
break;
|
|
mbp->msg_bufr += l;
|
|
if (mbp->msg_bufr < 0 || mbp->msg_bufr >= mbp->msg_bufs)
|
|
mbp->msg_bufr = 0;
|
|
}
|
|
mutex_spin_exit(&log_lock);
|
|
|
|
return error;
|
|
}
|
|
|
|
/*ARGSUSED*/
|
|
static int
|
|
logpoll(dev_t dev, int events, struct lwp *l)
|
|
{
|
|
int revents = 0;
|
|
|
|
if (events & (POLLIN | POLLRDNORM)) {
|
|
mutex_spin_enter(&log_lock);
|
|
if (msgbufp->msg_bufr != msgbufp->msg_bufx)
|
|
revents |= events & (POLLIN | POLLRDNORM);
|
|
else
|
|
selrecord(l, &log_selp);
|
|
mutex_spin_exit(&log_lock);
|
|
}
|
|
|
|
return revents;
|
|
}
|
|
|
|
static void
|
|
filt_logrdetach(struct knote *kn)
|
|
{
|
|
|
|
mutex_spin_enter(&log_lock);
|
|
selremove_knote(&log_selp, kn);
|
|
mutex_spin_exit(&log_lock);
|
|
}
|
|
|
|
static int
|
|
filt_logread(struct knote *kn, long hint)
|
|
{
|
|
int rv;
|
|
|
|
if ((hint & NOTE_SUBMIT) == 0)
|
|
mutex_spin_enter(&log_lock);
|
|
if (msgbufp->msg_bufr == msgbufp->msg_bufx) {
|
|
rv = 0;
|
|
} else if (msgbufp->msg_bufr < msgbufp->msg_bufx) {
|
|
kn->kn_data = msgbufp->msg_bufx - msgbufp->msg_bufr;
|
|
rv = 1;
|
|
} else {
|
|
kn->kn_data = (msgbufp->msg_bufs - msgbufp->msg_bufr) +
|
|
msgbufp->msg_bufx;
|
|
rv = 1;
|
|
}
|
|
if ((hint & NOTE_SUBMIT) == 0)
|
|
mutex_spin_exit(&log_lock);
|
|
|
|
return rv;
|
|
}
|
|
|
|
static const struct filterops logread_filtops = {
|
|
.f_isfd = 1,
|
|
.f_attach = NULL,
|
|
.f_detach = filt_logrdetach,
|
|
.f_event = filt_logread,
|
|
};
|
|
|
|
static int
|
|
logkqfilter(dev_t dev, struct knote *kn)
|
|
{
|
|
|
|
switch (kn->kn_filter) {
|
|
case EVFILT_READ:
|
|
kn->kn_fop = &logread_filtops;
|
|
break;
|
|
|
|
default:
|
|
return (EINVAL);
|
|
}
|
|
|
|
kn->kn_hook = NULL;
|
|
|
|
mutex_spin_enter(&log_lock);
|
|
selrecord_knote(&log_selp, kn);
|
|
mutex_spin_exit(&log_lock);
|
|
|
|
return (0);
|
|
}
|
|
|
|
void
|
|
logwakeup(void)
|
|
{
|
|
|
|
if (!cold && log_open) {
|
|
mutex_spin_enter(&log_lock);
|
|
selnotify(&log_selp, 0, NOTE_SUBMIT);
|
|
if (log_async)
|
|
softint_schedule(log_sih);
|
|
cv_broadcast(&log_cv);
|
|
mutex_spin_exit(&log_lock);
|
|
}
|
|
}
|
|
|
|
static void
|
|
logsoftintr(void *cookie)
|
|
{
|
|
pid_t pid;
|
|
|
|
if ((pid = log_pgid) != 0)
|
|
fownsignal(pid, SIGIO, 0, 0, NULL);
|
|
}
|
|
|
|
/*ARGSUSED*/
|
|
static int
|
|
logioctl(dev_t dev, u_long com, void *data, int flag, struct lwp *lwp)
|
|
{
|
|
long l;
|
|
|
|
switch (com) {
|
|
|
|
/* return number of characters immediately available */
|
|
case FIONREAD:
|
|
mutex_spin_enter(&log_lock);
|
|
l = msgbufp->msg_bufx - msgbufp->msg_bufr;
|
|
if (l < 0)
|
|
l += msgbufp->msg_bufs;
|
|
mutex_spin_exit(&log_lock);
|
|
*(int *)data = l;
|
|
break;
|
|
|
|
case FIONBIO:
|
|
break;
|
|
|
|
case FIOASYNC:
|
|
/* No locking needed, 'thread private'. */
|
|
log_async = (*((int *)data) != 0);
|
|
break;
|
|
|
|
case TIOCSPGRP:
|
|
case FIOSETOWN:
|
|
return fsetown(&log_pgid, com, data);
|
|
|
|
case TIOCGPGRP:
|
|
case FIOGETOWN:
|
|
return fgetown(log_pgid, com, data);
|
|
|
|
default:
|
|
return (EPASSTHROUGH);
|
|
}
|
|
return (0);
|
|
}
|
|
|
|
static void
|
|
logskip(struct kern_msgbuf *mbp)
|
|
{
|
|
/*
|
|
* Move forward read pointer to the next line
|
|
* in the buffer. Note that the buffer is
|
|
* a ring buffer so we should reset msg_bufr
|
|
* to 0 when msg_bufr exceeds msg_bufs.
|
|
*
|
|
* To prevent to loop forever, give up if we
|
|
* cannot find a newline in mbp->msg_bufs
|
|
* characters (the max size of the buffer).
|
|
*/
|
|
for (int i = 0; i < mbp->msg_bufs; i++) {
|
|
char c0 = mbp->msg_bufc[mbp->msg_bufr];
|
|
if (++mbp->msg_bufr >= mbp->msg_bufs)
|
|
mbp->msg_bufr = 0;
|
|
if (c0 == '\n')
|
|
break;
|
|
}
|
|
}
|
|
|
|
static void
|
|
logaddchar(struct kern_msgbuf *mbp, int c)
|
|
{
|
|
mbp->msg_bufc[mbp->msg_bufx++] = c;
|
|
if (mbp->msg_bufx < 0 || mbp->msg_bufx >= mbp->msg_bufs)
|
|
mbp->msg_bufx = 0;
|
|
|
|
/* If the buffer is full, keep the most recent data. */
|
|
if (mbp->msg_bufr == mbp->msg_bufx)
|
|
logskip(mbp);
|
|
}
|
|
|
|
void
|
|
logputchar(int c)
|
|
{
|
|
struct kern_msgbuf *mbp;
|
|
|
|
if (!cold)
|
|
mutex_spin_enter(&log_lock);
|
|
|
|
if (!msgbufenabled)
|
|
goto out;
|
|
|
|
mbp = msgbufp;
|
|
if (mbp->msg_magic != MSG_MAGIC) {
|
|
/*
|
|
* Arguably should panic or somehow notify the
|
|
* user... but how? Panic may be too drastic,
|
|
* and would obliterate the message being kicked
|
|
* out (maybe a panic itself), and printf
|
|
* would invoke us recursively. Silently punt
|
|
* for now. If syslog is running, it should
|
|
* notice.
|
|
*/
|
|
msgbufenabled = 0;
|
|
goto out;
|
|
|
|
}
|
|
|
|
logaddchar(mbp, c);
|
|
|
|
out:
|
|
if (!cold)
|
|
mutex_spin_exit(&log_lock);
|
|
}
|
|
|
|
/*
|
|
* sysctl helper routine for kern.msgbufsize and kern.msgbuf. For the
|
|
* former it merely checks the message buffer is set up. For the latter,
|
|
* it also copies out the data if necessary.
|
|
*/
|
|
static int
|
|
sysctl_msgbuf(SYSCTLFN_ARGS)
|
|
{
|
|
char *where = oldp;
|
|
size_t len, maxlen;
|
|
long beg, end;
|
|
extern kmutex_t log_lock;
|
|
int error;
|
|
|
|
if (!logenabled(msgbufp)) {
|
|
msgbufenabled = 0;
|
|
return (ENXIO);
|
|
}
|
|
|
|
switch (rnode->sysctl_num) {
|
|
case KERN_MSGBUFSIZE: {
|
|
struct sysctlnode node = *rnode;
|
|
int msg_bufs = (int)msgbufp->msg_bufs;
|
|
node.sysctl_data = &msg_bufs;
|
|
return (sysctl_lookup(SYSCTLFN_CALL(&node)));
|
|
}
|
|
case KERN_MSGBUF:
|
|
break;
|
|
default:
|
|
return (EOPNOTSUPP);
|
|
}
|
|
|
|
if (newp != NULL)
|
|
return (EPERM);
|
|
|
|
if (oldp == NULL) {
|
|
/* always return full buffer size */
|
|
*oldlenp = msgbufp->msg_bufs;
|
|
return (0);
|
|
}
|
|
|
|
sysctl_unlock();
|
|
|
|
/*
|
|
* First, copy from the write pointer to the end of
|
|
* message buffer.
|
|
*/
|
|
error = 0;
|
|
mutex_spin_enter(&log_lock);
|
|
maxlen = MIN(msgbufp->msg_bufs, *oldlenp);
|
|
beg = msgbufp->msg_bufx;
|
|
end = msgbufp->msg_bufs;
|
|
mutex_spin_exit(&log_lock);
|
|
|
|
while (maxlen > 0) {
|
|
len = MIN(end - beg, maxlen);
|
|
if (len == 0)
|
|
break;
|
|
/* XXX unlocked, but hardly matters. */
|
|
error = copyout(&msgbufp->msg_bufc[beg], where, len);
|
|
ktrmibio(-1, UIO_READ, where, len, error);
|
|
if (error)
|
|
break;
|
|
where += len;
|
|
maxlen -= len;
|
|
|
|
/*
|
|
* ... then, copy from the beginning of message buffer to
|
|
* the write pointer.
|
|
*/
|
|
beg = 0;
|
|
end = msgbufp->msg_bufx;
|
|
}
|
|
|
|
sysctl_relock();
|
|
return (error);
|
|
}
|
|
|
|
const struct cdevsw log_cdevsw = {
|
|
.d_open = logopen,
|
|
.d_close = logclose,
|
|
.d_read = logread,
|
|
.d_write = nowrite,
|
|
.d_ioctl = logioctl,
|
|
.d_stop = nostop,
|
|
.d_tty = notty,
|
|
.d_poll = logpoll,
|
|
.d_mmap = nommap,
|
|
.d_kqfilter = logkqfilter,
|
|
.d_discard = nodiscard,
|
|
.d_flag = D_OTHER | D_MPSAFE
|
|
};
|