subr_log.c revision 1.30 
1/*	$OpenBSD: subr_log.c,v 1.30 2015/05/06 08:52:17 mpi Exp $	*/
2/*	$NetBSD: subr_log.c,v 1.11 1996/03/30 22:24:44 christos Exp $	*/
3
4/*
5 * Copyright (c) 1982, 1986, 1993
6 *	The Regents of the University of California.  All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 * 3. Neither the name of the University nor the names of its contributors
17 *    may be used to endorse or promote products derived from this software
18 *    without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 *
32 *	@(#)subr_log.c	8.1 (Berkeley) 6/10/93
33 */
34
35/*
36 * Error log buffer for kernel printf's.
37 */
38
39#include <sys/param.h>
40#include <sys/systm.h>
41#include <sys/proc.h>
42#include <sys/vnode.h>
43#include <sys/ioctl.h>
44#include <sys/msgbuf.h>
45#include <sys/file.h>
46#include <sys/signalvar.h>
47#include <sys/syslog.h>
48#include <sys/poll.h>
49#include <sys/malloc.h>
50#include <sys/filedesc.h>
51#include <sys/socket.h>
52#include <sys/socketvar.h>
53
54#ifdef KTRACE
55#include <sys/ktrace.h>
56#endif
57
58#include <sys/mount.h>
59#include <sys/syscallargs.h>
60
61#define LOG_RDPRI	(PZERO + 1)
62
63#define LOG_ASYNC	0x04
64#define LOG_RDWAIT	0x08
65
66struct logsoftc {
67	int	sc_state;		/* see above for possibilities */
68	struct	selinfo sc_selp;	/* process waiting on select call */
69	int	sc_pgid;		/* process/group for async I/O */
70	uid_t	sc_siguid;		/* uid for process that set sc_pgid */
71	uid_t	sc_sigeuid;		/* euid for process that set sc_pgid */
72} logsoftc;
73
74int	log_open;			/* also used in log() */
75int	msgbufmapped;			/* is the message buffer mapped */
76struct	msgbuf *msgbufp;		/* the mapped buffer, itself. */
77struct	msgbuf *consbufp;		/* console message buffer. */
78struct file *syslogf;
79
80void filt_logrdetach(struct knote *kn);
81int filt_logread(struct knote *kn, long hint);
82
83struct filterops logread_filtops =
84	{ 1, NULL, filt_logrdetach, filt_logread};
85
86void
87initmsgbuf(caddr_t buf, size_t bufsize)
88{
89	struct msgbuf *mbp;
90	long new_bufs;
91
92	/* Sanity-check the given size. */
93	if (bufsize < sizeof(struct msgbuf))
94		return;
95
96	mbp = msgbufp = (struct msgbuf *)buf;
97
98	new_bufs = bufsize - offsetof(struct msgbuf, msg_bufc);
99	if ((mbp->msg_magic != MSG_MAGIC) || (mbp->msg_bufs != new_bufs) ||
100	    (mbp->msg_bufr < 0) || (mbp->msg_bufr >= mbp->msg_bufs) ||
101	    (mbp->msg_bufx < 0) || (mbp->msg_bufx >= mbp->msg_bufs)) {
102		/*
103		 * If the buffer magic number is wrong, has changed
104		 * size (which shouldn't happen often), or is
105		 * internally inconsistent, initialize it.
106		 */
107
108		memset(buf, 0, bufsize);
109		mbp->msg_magic = MSG_MAGIC;
110		mbp->msg_bufs = new_bufs;
111	}
112
113	/* Always start new buffer data on a new line. */
114	if (mbp->msg_bufx > 0 && mbp->msg_bufc[mbp->msg_bufx - 1] != '\n')
115		msgbuf_putchar(msgbufp, '\n');
116
117	/* mark it as ready for use. */
118	msgbufmapped = 1;
119}
120
121void
122initconsbuf(void)
123{
124	long new_bufs;
125
126	/* Set up a buffer to collect /dev/console output */
127	consbufp = malloc(CONSBUFSIZE, M_TEMP, M_NOWAIT|M_ZERO);
128	if (consbufp) {
129		new_bufs = CONSBUFSIZE - offsetof(struct msgbuf, msg_bufc);
130		consbufp->msg_magic = MSG_MAGIC;
131		consbufp->msg_bufs = new_bufs;
132	}
133}
134
135void
136msgbuf_putchar(struct msgbuf *mbp, const char c)
137{
138	if (mbp->msg_magic != MSG_MAGIC)
139		/* Nothing we can do */
140		return;
141
142	mbp->msg_bufc[mbp->msg_bufx++] = c;
143	mbp->msg_bufl = min(mbp->msg_bufl+1, mbp->msg_bufs);
144	if (mbp->msg_bufx < 0 || mbp->msg_bufx >= mbp->msg_bufs)
145		mbp->msg_bufx = 0;
146	/* If the buffer is full, keep the most recent data. */
147	if (mbp->msg_bufr == mbp->msg_bufx) {
148		if (++mbp->msg_bufr >= mbp->msg_bufs)
149			mbp->msg_bufr = 0;
150	}
151}
152
153/*ARGSUSED*/
154int
155logopen(dev_t dev, int flags, int mode, struct proc *p)
156{
157	if (log_open)
158		return (EBUSY);
159	log_open = 1;
160	return (0);
161}
162
163/*ARGSUSED*/
164int
165logclose(dev_t dev, int flag, int mode, struct proc *p)
166{
167
168	if (syslogf)
169		FRELE(syslogf, p);
170	syslogf = NULL;
171	log_open = 0;
172	logsoftc.sc_state = 0;
173	return (0);
174}
175
176/*ARGSUSED*/
177int
178logread(dev_t dev, struct uio *uio, int flag)
179{
180	struct msgbuf *mbp = msgbufp;
181	long l;
182	int s;
183	int error = 0;
184
185	s = splhigh();
186	while (mbp->msg_bufr == mbp->msg_bufx) {
187		if (flag & IO_NDELAY) {
188			splx(s);
189			return (EWOULDBLOCK);
190		}
191		logsoftc.sc_state |= LOG_RDWAIT;
192		error = tsleep(mbp, LOG_RDPRI | PCATCH,
193			       "klog", 0);
194		if (error) {
195			splx(s);
196			return (error);
197		}
198	}
199	splx(s);
200	logsoftc.sc_state &= ~LOG_RDWAIT;
201
202	while (uio->uio_resid > 0) {
203		l = mbp->msg_bufx - mbp->msg_bufr;
204		if (l < 0)
205			l = mbp->msg_bufs - mbp->msg_bufr;
206		l = min(l, uio->uio_resid);
207		if (l == 0)
208			break;
209		error = uiomovei(&mbp->msg_bufc[mbp->msg_bufr], (int)l, uio);
210		if (error)
211			break;
212		mbp->msg_bufr += l;
213		if (mbp->msg_bufr < 0 || mbp->msg_bufr >= mbp->msg_bufs)
214			mbp->msg_bufr = 0;
215	}
216	return (error);
217}
218
219/*ARGSUSED*/
220int
221logpoll(dev_t dev, int events, struct proc *p)
222{
223	int revents = 0;
224	int s = splhigh();
225
226	if (events & (POLLIN | POLLRDNORM)) {
227		if (msgbufp->msg_bufr != msgbufp->msg_bufx)
228			revents |= events & (POLLIN | POLLRDNORM);
229		else
230			selrecord(p, &logsoftc.sc_selp);
231	}
232	splx(s);
233	return (revents);
234}
235
236int
237logkqfilter(dev_t dev, struct knote *kn)
238{
239	struct klist *klist;
240	int s;
241
242	switch (kn->kn_filter) {
243	case EVFILT_READ:
244		klist = &logsoftc.sc_selp.si_note;
245		kn->kn_fop = &logread_filtops;
246		break;
247	default:
248		return (EINVAL);
249	}
250
251	kn->kn_hook = (void *)msgbufp;
252
253	s = splhigh();
254	SLIST_INSERT_HEAD(klist, kn, kn_selnext);
255	splx(s);
256
257	return (0);
258}
259
260void
261filt_logrdetach(struct knote *kn)
262{
263	int s = splhigh();
264
265	SLIST_REMOVE(&logsoftc.sc_selp.si_note, kn, knote, kn_selnext);
266	splx(s);
267}
268
269int
270filt_logread(struct knote *kn, long hint)
271{
272	struct  msgbuf *p = (struct  msgbuf *)kn->kn_hook;
273
274	kn->kn_data = (int)(p->msg_bufx - p->msg_bufr);
275
276	return (p->msg_bufx != p->msg_bufr);
277}
278
279void
280logwakeup(void)
281{
282	if (!log_open)
283		return;
284	selwakeup(&logsoftc.sc_selp);
285	if (logsoftc.sc_state & LOG_ASYNC)
286		csignal(logsoftc.sc_pgid, SIGIO,
287		    logsoftc.sc_siguid, logsoftc.sc_sigeuid);
288	if (logsoftc.sc_state & LOG_RDWAIT) {
289		wakeup(msgbufp);
290		logsoftc.sc_state &= ~LOG_RDWAIT;
291	}
292}
293
294/*ARGSUSED*/
295int
296logioctl(dev_t dev, u_long com, caddr_t data, int flag, struct proc *p)
297{
298	struct file *fp;
299	long l;
300	int error, s;
301
302	switch (com) {
303
304	/* return number of characters immediately available */
305	case FIONREAD:
306		s = splhigh();
307		l = msgbufp->msg_bufx - msgbufp->msg_bufr;
308		splx(s);
309		if (l < 0)
310			l += msgbufp->msg_bufs;
311		*(int *)data = l;
312		break;
313
314	case FIONBIO:
315		break;
316
317	case FIOASYNC:
318		if (*(int *)data)
319			logsoftc.sc_state |= LOG_ASYNC;
320		else
321			logsoftc.sc_state &= ~LOG_ASYNC;
322		break;
323
324	case TIOCSPGRP:
325		logsoftc.sc_pgid = *(int *)data;
326		logsoftc.sc_siguid = p->p_ucred->cr_ruid;
327		logsoftc.sc_sigeuid = p->p_ucred->cr_uid;
328		break;
329
330	case TIOCGPGRP:
331		*(int *)data = logsoftc.sc_pgid;
332		break;
333
334	case LIOCSFD:
335		if ((error = suser(p, 0)) != 0)
336			return (error);
337		if ((error = getsock(p, *(int *)data, &fp)) != 0)
338			return (error);
339		if (syslogf)
340			FRELE(syslogf, p);
341		syslogf = fp;
342		break;
343
344	default:
345		return (ENOTTY);
346	}
347	return (0);
348}
349
350int
351sys_sendsyslog(struct proc *p, void *v, register_t *retval)
352{
353	struct sys_sendsyslog_args /* {
354		syscallarg(const void *) buf;
355		syscallarg(size_t) nbyte;
356	} */ *uap = v;
357#ifdef KTRACE
358	struct iovec *ktriov = NULL;
359	int iovlen;
360#endif
361	struct iovec aiov;
362	struct uio auio;
363	struct file *f;
364	size_t len;
365	int error;
366
367	if (syslogf == NULL)
368		return (ENOTCONN);
369	f = syslogf;
370	FREF(f);
371
372	aiov.iov_base = (char *)SCARG(uap, buf);
373	aiov.iov_len = SCARG(uap, nbyte);
374	auio.uio_iov = &aiov;
375	auio.uio_iovcnt = 1;
376	auio.uio_segflg = UIO_USERSPACE;
377	auio.uio_rw = UIO_WRITE;
378	auio.uio_procp = p;
379	auio.uio_offset = 0;
380	auio.uio_resid = aiov.iov_len;
381#ifdef KTRACE
382	if (KTRPOINT(p, KTR_GENIO)) {
383		ktriov = mallocarray(auio.uio_iovcnt, sizeof(struct iovec),
384		    M_TEMP, M_WAITOK);
385		iovlen = auio.uio_iovcnt * sizeof (struct iovec);
386
387		memcpy(ktriov, auio.uio_iov, iovlen);
388	}
389#endif
390
391	len = auio.uio_resid;
392	error = sosend(f->f_data, NULL, &auio, NULL, NULL, 0);
393	if (error == 0)
394		len -= auio.uio_resid;
395
396#ifdef KTRACE
397	if (ktriov != NULL) {
398		if (error == 0)
399			ktrgenio(p, -1, UIO_WRITE, ktriov, len);
400		free(ktriov, M_TEMP, iovlen);
401	}
402#endif
403	FRELE(f, p);
404	return error;
405}
406