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 1.9 1995/08/07 07:58:17 davidg 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#define LOG_RDPRI (PZERO + 1)
51
52#define LOG_ASYNC 0x04
53#define LOG_RDWAIT 0x08
54
55struct logsoftc {
56 int sc_state; /* see above for possibilities */
57 struct selinfo sc_selp; /* process waiting on select call */
58 int sc_pgid; /* process/group for async I/O */
59} logsoftc;
60
61int log_open; /* also used in log() */
62
63/*ARGSUSED*/
64int
65logopen(dev, flags, mode, p)
66 dev_t dev;
67 int flags, mode;
68 struct proc *p;
69{
70 if (log_open)
71 return (EBUSY);
72 log_open = 1;
73 logsoftc.sc_pgid = p->p_pid; /* signal process only */
74 return (0);
75}
76
77/*ARGSUSED*/
78int
79logclose(dev, flag, mode, p)
80 dev_t dev;
81 int flag, mode;
82 struct proc *p;
83{
84
85 log_open = 0;
86 logsoftc.sc_state = 0;
87 return (0);
88}
89
90/*ARGSUSED*/
91int
92logread(dev, uio, flag)
93 dev_t dev;
94 struct uio *uio;
95 int flag;
96{
97 register struct msgbuf *mbp = msgbufp;
98 register long l;
99 register int s;
100 int error = 0;
101
102 s = splhigh();
103 while (mbp->msg_bufr == mbp->msg_bufx) {
104 if (flag & IO_NDELAY) {
105 splx(s);
106 return (EWOULDBLOCK);
107 }
108 logsoftc.sc_state |= LOG_RDWAIT;
109 if ((error = tsleep((caddr_t)mbp, LOG_RDPRI | PCATCH,
110 "klog", 0))) {
111 splx(s);
112 return (error);
113 }
114 }
115 splx(s);
116 logsoftc.sc_state &= ~LOG_RDWAIT;
117
118 while (uio->uio_resid > 0) {
119 l = mbp->msg_bufx - mbp->msg_bufr;
120 if (l < 0)
121 l = MSG_BSIZE - mbp->msg_bufr;
122 l = min(l, uio->uio_resid);
123 if (l == 0)
124 break;
125 error = uiomove((caddr_t)&mbp->msg_bufc[mbp->msg_bufr],
126 (int)l, uio);
127 if (error)
128 break;
129 mbp->msg_bufr += l;
130 if (mbp->msg_bufr >= MSG_BSIZE)
131 mbp->msg_bufr = 0;
132 }
133 return (error);
134}
135
136/*ARGSUSED*/
137int
138logselect(dev, rw, p)
139 dev_t dev;
140 int rw;
141 struct proc *p;
142{
143 int s = splhigh();
144
145 switch (rw) {
146
147 case FREAD:
148 if (msgbufp->msg_bufr != msgbufp->msg_bufx) {
149 splx(s);
150 return (1);
151 }
152 selrecord(p, &logsoftc.sc_selp);
153 break;
154 }
155 splx(s);
156 return (0);
157}
158
159void
160logwakeup()
161{
162 struct proc *p;
163
164 if (!log_open)
165 return;
166 selwakeup(&logsoftc.sc_selp);
167 if (logsoftc.sc_state & LOG_ASYNC) {
168 if (logsoftc.sc_pgid < 0)
169 gsignal(-logsoftc.sc_pgid, SIGIO);
170 else if ((p = pfind(logsoftc.sc_pgid)))
171 psignal(p, SIGIO);
172 }
173 if (logsoftc.sc_state & LOG_RDWAIT) {
174 wakeup((caddr_t)msgbufp);
175 logsoftc.sc_state &= ~LOG_RDWAIT;
176 }
177}
178
179/*ARGSUSED*/
180int
181logioctl(dev, com, data, flag, p)
182 dev_t dev;
183 int com;
184 caddr_t data;
185 int flag;
186 struct proc *p;
187{
188 long l;
189 int s;
190
191 switch (com) {
192
193 /* return number of characters immediately available */
194 case FIONREAD:
195 s = splhigh();
196 l = msgbufp->msg_bufx - msgbufp->msg_bufr;
197 splx(s);
198 if (l < 0)
199 l += MSG_BSIZE;
200 *(int *)data = l;
201 break;
202
203 case FIONBIO:
204 break;
205
206 case FIOASYNC:
207 if (*(int *)data)
208 logsoftc.sc_state |= LOG_ASYNC;
209 else
210 logsoftc.sc_state &= ~LOG_ASYNC;
211 break;
212
213 case TIOCSPGRP:
214 logsoftc.sc_pgid = *(int *)data;
215 break;
216
217 case TIOCGPGRP:
218 *(int *)data = logsoftc.sc_pgid;
219 break;
220
221 default:
222 return (ENOTTY);
223 }
224 return (0);
225}