subr_log.c revision 12521 
1/*
2 * Copyright (c) 1982, 1986, 1993
3 *	The Regents of the University of California.  All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
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.
20 *
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
31 * SUCH DAMAGE.
32 *
33 *	@(#)subr_log.c	8.1 (Berkeley) 6/10/93
34 * $Id: subr_log.c,v 1.11 1995/11/29 10:48:25 julian Exp $
35 */
36
37/*
38 * Error log buffer for kernel printf's.
39 */
40
41#include <sys/param.h>
42#include <sys/systm.h>
43#include <sys/proc.h>
44#include <sys/vnode.h>
45#include <sys/ioctl.h>
46#include <sys/msgbuf.h>
47#include <sys/file.h>
48#include <sys/signalvar.h>
49
50#ifdef JREMOD
51#include <sys/conf.h>
52#include <sys/kernel.h>
53#ifdef DEVFS
54#include <sys/devfsext.h>
55#endif /*DEVFS*/
56#define CDEV_MAJOR 7
57#endif /*JREMOD*/
58
59#define LOG_RDPRI	(PZERO + 1)
60
61#define LOG_ASYNC	0x04
62#define LOG_RDWAIT	0x08
63
64struct logsoftc {
65	int	sc_state;		/* see above for possibilities */
66	struct	selinfo sc_selp;	/* process waiting on select call */
67	int	sc_pgid;		/* process/group for async I/O */
68} logsoftc;
69
70int	log_open;			/* also used in log() */
71
72/*ARGSUSED*/
73int
74logopen(dev, flags, mode, p)
75	dev_t dev;
76	int flags, mode;
77	struct proc *p;
78{
79	if (log_open)
80		return (EBUSY);
81	log_open = 1;
82	logsoftc.sc_pgid = p->p_pid;		/* signal process only */
83	return (0);
84}
85
86/*ARGSUSED*/
87int
88logclose(dev, flag, mode, p)
89	dev_t dev;
90	int flag, mode;
91	struct proc *p;
92{
93
94	log_open = 0;
95	logsoftc.sc_state = 0;
96	return (0);
97}
98
99/*ARGSUSED*/
100int
101logread(dev, uio, flag)
102	dev_t dev;
103	struct uio *uio;
104	int flag;
105{
106	register struct msgbuf *mbp = msgbufp;
107	register long l;
108	register int s;
109	int error = 0;
110
111	s = splhigh();
112	while (mbp->msg_bufr == mbp->msg_bufx) {
113		if (flag & IO_NDELAY) {
114			splx(s);
115			return (EWOULDBLOCK);
116		}
117		logsoftc.sc_state |= LOG_RDWAIT;
118		if ((error = tsleep((caddr_t)mbp, LOG_RDPRI | PCATCH,
119		    "klog", 0))) {
120			splx(s);
121			return (error);
122		}
123	}
124	splx(s);
125	logsoftc.sc_state &= ~LOG_RDWAIT;
126
127	while (uio->uio_resid > 0) {
128		l = mbp->msg_bufx - mbp->msg_bufr;
129		if (l < 0)
130			l = MSG_BSIZE - mbp->msg_bufr;
131		l = min(l, uio->uio_resid);
132		if (l == 0)
133			break;
134		error = uiomove((caddr_t)&mbp->msg_bufc[mbp->msg_bufr],
135			(int)l, uio);
136		if (error)
137			break;
138		mbp->msg_bufr += l;
139		if (mbp->msg_bufr >= MSG_BSIZE)
140			mbp->msg_bufr = 0;
141	}
142	return (error);
143}
144
145/*ARGSUSED*/
146int
147logselect(dev, rw, p)
148	dev_t dev;
149	int rw;
150	struct proc *p;
151{
152	int s = splhigh();
153
154	switch (rw) {
155
156	case FREAD:
157		if (msgbufp->msg_bufr != msgbufp->msg_bufx) {
158			splx(s);
159			return (1);
160		}
161		selrecord(p, &logsoftc.sc_selp);
162		break;
163	}
164	splx(s);
165	return (0);
166}
167
168void
169logwakeup()
170{
171	struct proc *p;
172
173	if (!log_open)
174		return;
175	selwakeup(&logsoftc.sc_selp);
176	if (logsoftc.sc_state & LOG_ASYNC) {
177		if (logsoftc.sc_pgid < 0)
178			gsignal(-logsoftc.sc_pgid, SIGIO);
179		else if ((p = pfind(logsoftc.sc_pgid)))
180			psignal(p, SIGIO);
181	}
182	if (logsoftc.sc_state & LOG_RDWAIT) {
183		wakeup((caddr_t)msgbufp);
184		logsoftc.sc_state &= ~LOG_RDWAIT;
185	}
186}
187
188/*ARGSUSED*/
189int
190logioctl(dev, com, data, flag, p)
191	dev_t dev;
192	int com;
193	caddr_t data;
194	int flag;
195	struct proc *p;
196{
197	long l;
198	int s;
199
200	switch (com) {
201
202	/* return number of characters immediately available */
203	case FIONREAD:
204		s = splhigh();
205		l = msgbufp->msg_bufx - msgbufp->msg_bufr;
206		splx(s);
207		if (l < 0)
208			l += MSG_BSIZE;
209		*(int *)data = l;
210		break;
211
212	case FIONBIO:
213		break;
214
215	case FIOASYNC:
216		if (*(int *)data)
217			logsoftc.sc_state |= LOG_ASYNC;
218		else
219			logsoftc.sc_state &= ~LOG_ASYNC;
220		break;
221
222	case TIOCSPGRP:
223		logsoftc.sc_pgid = *(int *)data;
224		break;
225
226	case TIOCGPGRP:
227		*(int *)data = logsoftc.sc_pgid;
228		break;
229
230	default:
231		return (ENOTTY);
232	}
233	return (0);
234}
235
236#ifdef JREMOD
237struct cdevsw log_cdevsw =
238	{ logopen,	logclose,	logread,	nowrite,	/*7*/
239	  logioctl,	nostop,		nullreset,	nodevtotty,/* klog */
240	  logselect,	nommap,		NULL };
241
242static log_devsw_installed = 0;
243
244static void 	log_drvinit(void *unused)
245{
246	dev_t dev;
247
248	if( ! log_devsw_installed ) {
249		dev = makedev(CDEV_MAJOR,0);
250		cdevsw_add(&dev,&log_cdevsw,NULL);
251		log_devsw_installed = 1;
252#ifdef DEVFS
253		{
254			int x;
255/* default for a simple device with no probe routine (usually delete this) */
256			x=devfs_add_devsw(
257/*	path	name	devsw		minor	type   uid gid perm*/
258	"/",	"log",	major(dev),	0,	DV_CHR,	0,  0, 0600);
259		}
260#endif
261    	}
262}
263
264SYSINIT(logdev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR,log_drvinit,NULL)
265
266#endif /* JREMOD */
267
268