1 /** $MirOS: src/sys/kern/subr_log.c,v 1.6 2010/09/21 17:42:53 tg Exp $ */
2 /* $OpenBSD: subr_log.c,v 1.13 2005/04/20 00:08:50 deraadt Exp $ */
3 /* $NetBSD: subr_log.c,v 1.11 1996/03/30 22:24:44 christos Exp $ */
4
5 /*
6 * Copyright (c) 1982, 1986, 1993
7 * The Regents of the University of California. All rights reserved.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
17 * 3. 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 */
35
36 /*
37 * Error log buffer for kernel printf's.
38 */
39
40 #include <sys/param.h>
41 #include <sys/systm.h>
42 #include <sys/proc.h>
43 #include <sys/vnode.h>
44 #include <sys/ioctl.h>
45 #include <sys/msgbuf.h>
46 #include <sys/file.h>
47 #include <sys/signalvar.h>
48 #include <sys/syslog.h>
49 #include <sys/conf.h>
50 #include <sys/poll.h>
51
52 #include <dev/rndvar.h>
53
54 #define LOG_RDPRI (PZERO + 1)
55
56 #define LOG_ASYNC 0x04
57 #define LOG_RDWAIT 0x08
58
59 struct logsoftc {
60 int sc_state; /* see above for possibilities */
61 struct selinfo sc_selp; /* process waiting on select call */
62 int sc_pgid; /* process/group for async I/O */
63 uid_t sc_siguid; /* uid for process that set sc_pgid */
64 uid_t sc_sigeuid; /* euid for process that set sc_pgid */
65 } logsoftc;
66
67 int log_open; /* also used in log() */
68 int msgbufmapped; /* is the message buffer mapped */
69 int msgbufenabled; /* is logging to the buffer enabled */
70 struct msgbuf *msgbufp; /* the mapped buffer, itself. */
71
72 void filt_logrdetach(struct knote *kn);
73 int filt_logread(struct knote *kn, long hint);
74
75 struct filterops logread_filtops =
76 { 1, NULL, filt_logrdetach, filt_logread};
77
78 void
initmsgbuf(buf,bufsize)79 initmsgbuf(buf, bufsize)
80 caddr_t buf;
81 size_t bufsize;
82 {
83 struct msgbuf *mbp;
84 long new_bufs;
85
86 rnd_lopool_addh(buf, bufsize);
87
88 /* Sanity-check the given size. */
89 if (bufsize < sizeof(struct msgbuf))
90 return;
91
92 mbp = msgbufp = (struct msgbuf *)buf;
93
94 new_bufs = bufsize - offsetof(struct msgbuf, msg_bufc);
95 if ((mbp->msg_magic != MSG_MAGIC) || (mbp->msg_bufs != new_bufs) ||
96 (mbp->msg_bufr < 0) || (mbp->msg_bufr >= mbp->msg_bufs) ||
97 (mbp->msg_bufx < 0) || (mbp->msg_bufx >= mbp->msg_bufs)) {
98 /*
99 * If the buffer magic number is wrong, has changed
100 * size (which shouldn't happen often), or is
101 * internally inconsistent, initialize it.
102 */
103
104 bzero(buf, bufsize);
105 mbp->msg_magic = MSG_MAGIC;
106 mbp->msg_bufs = new_bufs;
107 }
108
109 /* Always start new buffer data on a new line. */
110 if (mbp->msg_bufx > 0 && mbp->msg_bufc[mbp->msg_bufx - 1] != '\n')
111 msgbuf_putchar('\n');
112
113 /* mark it as ready for use. */
114 msgbufmapped = msgbufenabled = 1;
115 }
116
117 void
msgbuf_putchar(const char c)118 msgbuf_putchar(const char c)
119 {
120 struct msgbuf *mbp = msgbufp;
121
122 if (mbp->msg_magic != MSG_MAGIC)
123 /* Nothing we can do */
124 return;
125
126 mbp->msg_bufc[mbp->msg_bufx++] = c;
127 mbp->msg_bufl = min(mbp->msg_bufl+1, mbp->msg_bufs);
128 if (mbp->msg_bufx < 0 || mbp->msg_bufx >= mbp->msg_bufs)
129 mbp->msg_bufx = 0;
130 /* If the buffer is full, keep the most recent data. */
131 if (mbp->msg_bufr == mbp->msg_bufx) {
132 if (++mbp->msg_bufr >= mbp->msg_bufs)
133 mbp->msg_bufr = 0;
134 }
135 }
136
137 /*ARGSUSED*/
138 int
logopen(dev,flags,mode,p)139 logopen(dev, flags, mode, p)
140 dev_t dev;
141 int flags, mode;
142 struct proc *p;
143 {
144 if (log_open)
145 return (EBUSY);
146 log_open = 1;
147 return (0);
148 }
149
150 /*ARGSUSED*/
151 int
logclose(dev,flag,mode,p)152 logclose(dev, flag, mode, p)
153 dev_t dev;
154 int flag, mode;
155 struct proc *p;
156 {
157
158 log_open = 0;
159 logsoftc.sc_state = 0;
160 return (0);
161 }
162
163 /*ARGSUSED*/
164 int
logread(dev,uio,flag)165 logread(dev, uio, flag)
166 dev_t dev;
167 struct uio *uio;
168 int flag;
169 {
170 struct msgbuf *mbp = msgbufp;
171 long l;
172 int s;
173 int error = 0;
174
175 s = splhigh();
176 while (mbp->msg_bufr == mbp->msg_bufx) {
177 if (flag & IO_NDELAY) {
178 splx(s);
179 return (EWOULDBLOCK);
180 }
181 logsoftc.sc_state |= LOG_RDWAIT;
182 error = tsleep(mbp, LOG_RDPRI | PCATCH,
183 "klog", 0);
184 if (error) {
185 splx(s);
186 return (error);
187 }
188 }
189 splx(s);
190 logsoftc.sc_state &= ~LOG_RDWAIT;
191
192 while (uio->uio_resid > 0) {
193 l = mbp->msg_bufx - mbp->msg_bufr;
194 if (l < 0)
195 l = mbp->msg_bufs - mbp->msg_bufr;
196 l = min(l, uio->uio_resid);
197 if (l == 0)
198 break;
199 error = uiomove(&mbp->msg_bufc[mbp->msg_bufr], (int)l, uio);
200 if (error)
201 break;
202 mbp->msg_bufr += l;
203 if (mbp->msg_bufr < 0 || mbp->msg_bufr >= mbp->msg_bufs)
204 mbp->msg_bufr = 0;
205 }
206 return (error);
207 }
208
209 /*ARGSUSED*/
210 int
logpoll(dev,events,p)211 logpoll(dev, events, p)
212 dev_t dev;
213 int events;
214 struct proc *p;
215 {
216 int revents = 0;
217 int s = splhigh();
218
219 if (events & (POLLIN | POLLRDNORM)) {
220 if (msgbufp->msg_bufr != msgbufp->msg_bufx)
221 revents |= events & (POLLIN | POLLRDNORM);
222 else
223 selrecord(p, &logsoftc.sc_selp);
224 }
225 splx(s);
226 return (revents);
227 }
228
229 int
logkqfilter(dev_t dev,struct knote * kn)230 logkqfilter(dev_t dev, struct knote *kn)
231 {
232 struct klist *klist;
233 int s;
234
235 switch (kn->kn_filter) {
236 case EVFILT_READ:
237 klist = &logsoftc.sc_selp.si_note;
238 kn->kn_fop = &logread_filtops;
239 break;
240 default:
241 return (1);
242 }
243
244 kn->kn_hook = (void *)msgbufp;
245
246 s = splhigh();
247 SLIST_INSERT_HEAD(klist, kn, kn_selnext);
248 splx(s);
249
250 return (0);
251 }
252
253 void
filt_logrdetach(struct knote * kn)254 filt_logrdetach(struct knote *kn)
255 {
256 int s = splhigh();
257
258 SLIST_REMOVE(&logsoftc.sc_selp.si_note, kn, knote, kn_selnext);
259 splx(s);
260 }
261
262 int
filt_logread(struct knote * kn,long hint)263 filt_logread(struct knote *kn, long hint)
264 {
265 struct msgbuf *p = (struct msgbuf *)kn->kn_hook;
266
267 kn->kn_data = (int)(p->msg_bufx - p->msg_bufr);
268
269 return (p->msg_bufx != p->msg_bufr);
270 }
271
272 void
logwakeup()273 logwakeup()
274 {
275 if (!log_open)
276 return;
277 selwakeup(&logsoftc.sc_selp);
278 if (logsoftc.sc_state & LOG_ASYNC)
279 csignal(logsoftc.sc_pgid, SIGIO,
280 logsoftc.sc_siguid, logsoftc.sc_sigeuid);
281 if (logsoftc.sc_state & LOG_RDWAIT) {
282 wakeup(msgbufp);
283 logsoftc.sc_state &= ~LOG_RDWAIT;
284 }
285 KNOTE(&logsoftc.sc_selp.si_note, 0);
286 }
287
288 /*ARGSUSED*/
289 int
logioctl(dev,com,data,flag,p)290 logioctl(dev, com, data, flag, p)
291 dev_t dev;
292 u_long com;
293 caddr_t data;
294 int flag;
295 struct proc *p;
296 {
297 long l;
298 int s;
299
300 switch (com) {
301
302 /* return number of characters immediately available */
303 case FIONREAD:
304 s = splhigh();
305 l = msgbufp->msg_bufx - msgbufp->msg_bufr;
306 splx(s);
307 if (l < 0)
308 l += msgbufp->msg_bufs;
309 *(int *)data = l;
310 break;
311
312 case FIONBIO:
313 break;
314
315 case FIOASYNC:
316 if (*(int *)data)
317 logsoftc.sc_state |= LOG_ASYNC;
318 else
319 logsoftc.sc_state &= ~LOG_ASYNC;
320 break;
321
322 case TIOCSPGRP:
323 logsoftc.sc_pgid = *(int *)data;
324 logsoftc.sc_siguid = p->p_cred->p_ruid;
325 logsoftc.sc_sigeuid = p->p_ucred->cr_uid;
326 break;
327
328 case TIOCGPGRP:
329 *(int *)data = logsoftc.sc_pgid;
330 break;
331
332 default:
333 return (-1);
334 }
335 return (0);
336 }
337