2 * Copyright (c) 1982, 1986, 1993
3 * The Regents of the University of California. All rights reserved.
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. All advertising materials mentioning features or use of this software
14 * must display the following acknowledgement:
15 * This product includes software developed by the University of
16 * California, Berkeley and its contributors.
17 * 4. Neither the name of the University nor the names of its contributors
18 * may be used to endorse or promote products derived from this software
19 * without specific prior written permission.
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * @(#)subr_log.c 8.1 (Berkeley) 6/10/93
34 * $FreeBSD: src/sys/kern/subr_log.c,v 1.39.2.2 2001/06/02 08:11:25 phk Exp $
35 * $DragonFly: src/sys/kern/subr_log.c,v 1.8 2005/06/06 15:02:28 dillon Exp $
39 * Error log buffer for kernel printf's.
42 #include <sys/param.h>
43 #include <sys/systm.h>
46 #include <sys/vnode.h>
47 #include <sys/filio.h>
48 #include <sys/ttycom.h>
49 #include <sys/msgbuf.h>
50 #include <sys/signalvar.h>
51 #include <sys/kernel.h>
53 #include <sys/filedesc.h>
54 #include <sys/sysctl.h>
55 #include <sys/thread2.h>
57 #define LOG_ASYNC 0x04
58 #define LOG_RDWAIT 0x08
60 static d_open_t logopen
;
61 static d_close_t logclose
;
62 static d_read_t logread
;
63 static d_ioctl_t logioctl
;
64 static d_poll_t logpoll
;
66 static void logtimeout(void *arg
);
69 static struct cdevsw log_cdevsw
= {
83 /* strategy */ nostrategy
,
88 static struct logsoftc
{
89 int sc_state
; /* see above for possibilities */
90 struct selinfo sc_selp
; /* process waiting on select call */
91 struct sigio
*sc_sigio
; /* information for async I/O */
92 struct callout sc_callout
; /* callout to wakeup syslog */
95 int log_open
; /* also used in log() */
97 /* Times per second to check for a pending syslog wakeup. */
98 static int log_wakeups_per_second
= 5;
99 SYSCTL_INT(_kern
, OID_AUTO
, log_wakeups_per_second
, CTLFLAG_RW
,
100 &log_wakeups_per_second
, 0, "");
104 logopen(dev_t dev
, int flags
, int mode
, struct thread
*td
)
106 struct proc
*p
= td
->td_proc
;
112 callout_init(&logsoftc
.sc_callout
);
113 fsetown(p
->p_pid
, &logsoftc
.sc_sigio
); /* signal process only */
114 callout_reset(&logsoftc
.sc_callout
, hz
/ log_wakeups_per_second
,
121 logclose(dev_t dev
, int flag
, int mode
, struct thread
*td
)
125 callout_stop(&logsoftc
.sc_callout
);
126 logsoftc
.sc_state
= 0;
127 funsetown(logsoftc
.sc_sigio
);
133 logread(dev_t dev
, struct uio
*uio
, int flag
)
135 struct msgbuf
*mbp
= msgbufp
;
140 while (mbp
->msg_bufr
== mbp
->msg_bufx
) {
141 if (flag
& IO_NDELAY
) {
143 return (EWOULDBLOCK
);
145 logsoftc
.sc_state
|= LOG_RDWAIT
;
146 if ((error
= tsleep((caddr_t
)mbp
, PCATCH
, "klog", 0))) {
152 logsoftc
.sc_state
&= ~LOG_RDWAIT
;
154 while (uio
->uio_resid
> 0) {
155 l
= mbp
->msg_bufx
- mbp
->msg_bufr
;
157 l
= mbp
->msg_size
- mbp
->msg_bufr
;
158 l
= min(l
, uio
->uio_resid
);
161 error
= uiomove((caddr_t
)msgbufp
->msg_ptr
+ mbp
->msg_bufr
,
166 if (mbp
->msg_bufr
>= mbp
->msg_size
)
174 logpoll(dev_t dev
, int events
, struct thread
*td
)
179 if (events
& (POLLIN
| POLLRDNORM
)) {
180 if (msgbufp
->msg_bufr
!= msgbufp
->msg_bufx
)
181 revents
|= events
& (POLLIN
| POLLRDNORM
);
183 selrecord(td
, &logsoftc
.sc_selp
);
190 logtimeout(void *arg
)
195 if (msgbuftrigger
== 0) {
196 callout_reset(&logsoftc
.sc_callout
,
197 hz
/ log_wakeups_per_second
, logtimeout
, NULL
);
201 selwakeup(&logsoftc
.sc_selp
);
202 if ((logsoftc
.sc_state
& LOG_ASYNC
) && logsoftc
.sc_sigio
!= NULL
)
203 pgsigio(logsoftc
.sc_sigio
, SIGIO
, 0);
204 if (logsoftc
.sc_state
& LOG_RDWAIT
) {
205 wakeup((caddr_t
)msgbufp
);
206 logsoftc
.sc_state
&= ~LOG_RDWAIT
;
208 callout_reset(&logsoftc
.sc_callout
, hz
/ log_wakeups_per_second
,
214 logioctl(dev_t dev
, u_long com
, caddr_t data
, int flag
, struct thread
*td
)
220 /* return number of characters immediately available */
223 l
= msgbufp
->msg_bufx
- msgbufp
->msg_bufr
;
226 l
+= msgbufp
->msg_size
;
235 logsoftc
.sc_state
|= LOG_ASYNC
;
237 logsoftc
.sc_state
&= ~LOG_ASYNC
;
241 return (fsetown(*(int *)data
, &logsoftc
.sc_sigio
));
244 *(int *)data
= fgetown(logsoftc
.sc_sigio
);
247 /* This is deprecated, FIOSETOWN should be used instead. */
249 return (fsetown(-(*(int *)data
), &logsoftc
.sc_sigio
));
251 /* This is deprecated, FIOGETOWN should be used instead */
253 *(int *)data
= -fgetown(logsoftc
.sc_sigio
);
263 log_drvinit(void *unused
)
265 cdevsw_add(&log_cdevsw
, 0, 0);
266 make_dev(&log_cdevsw
, 0, UID_ROOT
, GID_WHEEL
, 0600, "klog");
269 SYSINIT(logdev
,SI_SUB_DRIVERS
,SI_ORDER_MIDDLE
+CDEV_MAJOR
,log_drvinit
,NULL
)