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 * 4. Neither the name of the University nor the names of its contributors
14 * may be used to endorse or promote products derived from this software
15 * without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 *
29 * @(#)subr_log.c 8.1 (Berkeley) 6/10/93
30 */
31
32/*
33 * Error log buffer for kernel printf's.
34 */
35
36#include <sys/cdefs.h>
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37__FBSDID("$FreeBSD: head/sys/kern/subr_log.c 216952 2011-01-04 10:59:38Z kib $");
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| 37__FBSDID("$FreeBSD: head/sys/kern/subr_log.c 230866 2012-02-01 14:34:52Z kib $"); |
38
39#include <sys/param.h>
40#include <sys/systm.h>
41#include <sys/conf.h>
42#include <sys/proc.h>
43#include <sys/vnode.h>
44#include <sys/filio.h>
45#include <sys/ttycom.h>
46#include <sys/msgbuf.h>
47#include <sys/signalvar.h>
48#include <sys/kernel.h>
49#include <sys/poll.h>
50#include <sys/filedesc.h>
51#include <sys/sysctl.h>
52
53#define LOG_RDPRI (PZERO + 1)
54
55#define LOG_ASYNC 0x04
56
57static d_open_t logopen;
58static d_close_t logclose;
59static d_read_t logread;
60static d_ioctl_t logioctl;
61static d_poll_t logpoll;
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| 62static d_kqfilter_t logkqfilter; |
63
64static void logtimeout(void *arg);
65
66static struct cdevsw log_cdevsw = {
67 .d_version = D_VERSION,
68 .d_open = logopen,
69 .d_close = logclose,
70 .d_read = logread,
71 .d_ioctl = logioctl,
72 .d_poll = logpoll,
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| 73 .d_kqfilter = logkqfilter, |
74 .d_name = "log",
75};
76
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77static int logkqread(struct knote *note, long hint);
78static void logkqdetach(struct knote *note);
79
80static struct filterops log_read_filterops = {
81 .f_isfd = 1,
82 .f_attach = NULL,
83 .f_detach = logkqdetach,
84 .f_event = logkqread,
85};
86 |
87static struct logsoftc {
88 int sc_state; /* see above for possibilities */
89 struct selinfo sc_selp; /* process waiting on select call */
90 struct sigio *sc_sigio; /* information for async I/O */
91 struct callout sc_callout; /* callout to wakeup syslog */
92} logsoftc;
93
94int log_open; /* also used in log() */
95static struct cv log_wakeup;
96struct mtx msgbuf_lock;
97MTX_SYSINIT(msgbuf_lock, &msgbuf_lock, "msgbuf lock", MTX_DEF);
98
99/* Times per second to check for a pending syslog wakeup. */
100static int log_wakeups_per_second = 5;
101SYSCTL_INT(_kern, OID_AUTO, log_wakeups_per_second, CTLFLAG_RW,
102 &log_wakeups_per_second, 0, "");
103
104/*ARGSUSED*/
105static int
106logopen(struct cdev *dev, int flags, int mode, struct thread *td)
107{
108
109 if (log_wakeups_per_second < 1) {
110 printf("syslog wakeup is less than one. Adjusting to 1.\n");
111 log_wakeups_per_second = 1;
112 }
113
114 mtx_lock(&msgbuf_lock);
115 if (log_open) {
116 mtx_unlock(&msgbuf_lock);
117 return (EBUSY);
118 }
119 log_open = 1;
120 callout_reset(&logsoftc.sc_callout, hz / log_wakeups_per_second,
121 logtimeout, NULL);
122 mtx_unlock(&msgbuf_lock);
123
124 fsetown(td->td_proc->p_pid, &logsoftc.sc_sigio); /* signal process only */
125 return (0);
126}
127
128/*ARGSUSED*/
129static int
130logclose(struct cdev *dev, int flag, int mode, struct thread *td)
131{
132
133 funsetown(&logsoftc.sc_sigio);
134
135 mtx_lock(&msgbuf_lock);
136 callout_stop(&logsoftc.sc_callout);
137 logsoftc.sc_state = 0;
138 log_open = 0;
139 mtx_unlock(&msgbuf_lock);
140
141 return (0);
142}
143
144/*ARGSUSED*/
145static int
146logread(struct cdev *dev, struct uio *uio, int flag)
147{
148 char buf[128];
149 struct msgbuf *mbp = msgbufp;
150 int error = 0, l;
151
152 mtx_lock(&msgbuf_lock);
153 while (msgbuf_getcount(mbp) == 0) {
154 if (flag & IO_NDELAY) {
155 mtx_unlock(&msgbuf_lock);
156 return (EWOULDBLOCK);
157 }
158 if ((error = cv_wait_sig(&log_wakeup, &msgbuf_lock)) != 0) {
159 mtx_unlock(&msgbuf_lock);
160 return (error);
161 }
162 }
163
164 while (uio->uio_resid > 0) {
165 l = imin(sizeof(buf), uio->uio_resid);
166 l = msgbuf_getbytes(mbp, buf, l);
167 if (l == 0)
168 break;
169 mtx_unlock(&msgbuf_lock);
170 error = uiomove(buf, l, uio);
171 if (error || uio->uio_resid == 0)
172 return (error);
173 mtx_lock(&msgbuf_lock);
174 }
175 mtx_unlock(&msgbuf_lock);
176 return (error);
177}
178
179/*ARGSUSED*/
180static int
181logpoll(struct cdev *dev, int events, struct thread *td)
182{
183 int revents = 0;
184
185 if (events & (POLLIN | POLLRDNORM)) {
186 mtx_lock(&msgbuf_lock);
187 if (msgbuf_getcount(msgbufp) > 0)
188 revents |= events & (POLLIN | POLLRDNORM);
189 else
190 selrecord(td, &logsoftc.sc_selp);
191 mtx_unlock(&msgbuf_lock);
192 }
193 return (revents);
194}
195
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196static int
197logkqfilter(struct cdev *dev, struct knote *kn)
198{
199
200 if (kn->kn_filter != EVFILT_READ)
201 return (EINVAL);
202
203 kn->kn_fop = &log_read_filterops;
204 kn->kn_hook = NULL;
205
206 mtx_lock(&msgbuf_lock);
207 knlist_add(&logsoftc.sc_selp.si_note, kn, 1);
208 mtx_unlock(&msgbuf_lock);
209 return (0);
210}
211
212static int
213logkqread(struct knote *kn, long hint)
214{
215
216 mtx_assert(&msgbuf_lock, MA_OWNED);
217 kn->kn_data = msgbuf_getcount(msgbufp);
218 return (kn->kn_data != 0);
219}
220 |
221static void
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222logkqdetach(struct knote *kn)
223{
224
225 mtx_lock(&msgbuf_lock);
226 knlist_remove(&logsoftc.sc_selp.si_note, kn, 1);
227 mtx_unlock(&msgbuf_lock);
228}
229
230static void |
231logtimeout(void *arg)
232{
233
234 if (!log_open)
235 return;
236 if (log_wakeups_per_second < 1) {
237 printf("syslog wakeup is less than one. Adjusting to 1.\n");
238 log_wakeups_per_second = 1;
239 }
240 if (msgbuftrigger == 0) {
241 callout_schedule(&logsoftc.sc_callout,
242 hz / log_wakeups_per_second);
243 return;
244 }
245 msgbuftrigger = 0;
246 selwakeuppri(&logsoftc.sc_selp, LOG_RDPRI);
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| 247 KNOTE_LOCKED(&logsoftc.sc_selp.si_note, 0); |
248 if ((logsoftc.sc_state & LOG_ASYNC) && logsoftc.sc_sigio != NULL)
249 pgsigio(&logsoftc.sc_sigio, SIGIO, 0);
250 cv_broadcastpri(&log_wakeup, LOG_RDPRI);
251 callout_schedule(&logsoftc.sc_callout, hz / log_wakeups_per_second);
252}
253
254/*ARGSUSED*/
255static int
256logioctl(struct cdev *dev, u_long com, caddr_t data, int flag, struct thread *td)
257{
258
259 switch (com) {
260
261 /* return number of characters immediately available */
262 case FIONREAD:
263 *(int *)data = msgbuf_getcount(msgbufp);
264 break;
265
266 case FIONBIO:
267 break;
268
269 case FIOASYNC:
270 mtx_lock(&msgbuf_lock);
271 if (*(int *)data)
272 logsoftc.sc_state |= LOG_ASYNC;
273 else
274 logsoftc.sc_state &= ~LOG_ASYNC;
275 mtx_unlock(&msgbuf_lock);
276 break;
277
278 case FIOSETOWN:
279 return (fsetown(*(int *)data, &logsoftc.sc_sigio));
280
281 case FIOGETOWN:
282 *(int *)data = fgetown(&logsoftc.sc_sigio);
283 break;
284
285 /* This is deprecated, FIOSETOWN should be used instead. */
286 case TIOCSPGRP:
287 return (fsetown(-(*(int *)data), &logsoftc.sc_sigio));
288
289 /* This is deprecated, FIOGETOWN should be used instead */
290 case TIOCGPGRP:
291 *(int *)data = -fgetown(&logsoftc.sc_sigio);
292 break;
293
294 default:
295 return (ENOTTY);
296 }
297 return (0);
298}
299
300static void
301log_drvinit(void *unused)
302{
303
304 cv_init(&log_wakeup, "klog");
305 callout_init_mtx(&logsoftc.sc_callout, &msgbuf_lock, 0);
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| 306 knlist_init_mtx(&logsoftc.sc_selp.si_note, &msgbuf_lock); |
307 make_dev_credf(MAKEDEV_ETERNAL, &log_cdevsw, 0, NULL, UID_ROOT,
308 GID_WHEEL, 0600, "klog");
309}
310
311SYSINIT(logdev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE,log_drvinit,NULL);
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