subr_log.c revision 1.21 
1/*	$OpenBSD: subr_log.c,v 1.21 2014/07/12 18:43:32 tedu 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/conf.h>
49#include <sys/poll.h>
50#include <sys/malloc.h>
51#include <sys/filedesc.h>
52#include <sys/socket.h>
53#include <sys/socketvar.h>
54
55#ifdef KTRACE
56#include <sys/ktrace.h>
57#endif
58
59#include <sys/mount.h>
60#include <sys/syscallargs.h>
61
62#define LOG_RDPRI	(PZERO + 1)
63
64#define LOG_ASYNC	0x04
65#define LOG_RDWAIT	0x08
66
67struct logsoftc {
68	int	sc_state;		/* see above for possibilities */
69	struct	selinfo sc_selp;	/* process waiting on select call */
70	int	sc_pgid;		/* process/group for async I/O */
71	uid_t	sc_siguid;		/* uid for process that set sc_pgid */
72	uid_t	sc_sigeuid;		/* euid for process that set sc_pgid */
73} logsoftc;
74
75int	log_open;			/* also used in log() */
76int	msgbufmapped;			/* is the message buffer mapped */
77int	msgbufenabled;			/* is logging to the buffer enabled */
78struct	msgbuf *msgbufp;		/* the mapped buffer, itself. */
79struct file *syslogf;
80
81void filt_logrdetach(struct knote *kn);
82int filt_logread(struct knote *kn, long hint);
83
84struct filterops logread_filtops =
85	{ 1, NULL, filt_logrdetach, filt_logread};
86
87void
88initmsgbuf(caddr_t buf, size_t bufsize)
89{
90	struct msgbuf *mbp;
91	long new_bufs;
92
93	/* Sanity-check the given size. */
94	if (bufsize < sizeof(struct msgbuf))
95		return;
96
97	mbp = msgbufp = (struct msgbuf *)buf;
98
99	new_bufs = bufsize - offsetof(struct msgbuf, msg_bufc);
100	if ((mbp->msg_magic != MSG_MAGIC) || (mbp->msg_bufs != new_bufs) ||
101	    (mbp->msg_bufr < 0) || (mbp->msg_bufr >= mbp->msg_bufs) ||
102	    (mbp->msg_bufx < 0) || (mbp->msg_bufx >= mbp->msg_bufs)) {
103		/*
104		 * If the buffer magic number is wrong, has changed
105		 * size (which shouldn't happen often), or is
106		 * internally inconsistent, initialize it.
107		 */
108
109		memset(buf, 0, bufsize);
110		mbp->msg_magic = MSG_MAGIC;
111		mbp->msg_bufs = new_bufs;
112	}
113
114	/* Always start new buffer data on a new line. */
115	if (mbp->msg_bufx > 0 && mbp->msg_bufc[mbp->msg_bufx - 1] != '\n')
116		msgbuf_putchar('\n');
117
118	/* mark it as ready for use. */
119	msgbufmapped = msgbufenabled = 1;
120}
121
122void
123msgbuf_putchar(const char c)
124{
125	struct msgbuf *mbp = msgbufp;
126
127	if (mbp->msg_magic != MSG_MAGIC)
128		/* Nothing we can do */
129		return;
130
131	mbp->msg_bufc[mbp->msg_bufx++] = c;
132	mbp->msg_bufl = min(mbp->msg_bufl+1, mbp->msg_bufs);
133	if (mbp->msg_bufx < 0 || mbp->msg_bufx >= mbp->msg_bufs)
134		mbp->msg_bufx = 0;
135	/* If the buffer is full, keep the most recent data. */
136	if (mbp->msg_bufr == mbp->msg_bufx) {
137		if (++mbp->msg_bufr >= mbp->msg_bufs)
138			mbp->msg_bufr = 0;
139	}
140}
141
142/*ARGSUSED*/
143int
144logopen(dev_t dev, int flags, int mode, struct proc *p)
145{
146	if (log_open)
147		return (EBUSY);
148	log_open = 1;
149	return (0);
150}
151
152/*ARGSUSED*/
153int
154logclose(dev_t dev, int flag, int mode, struct proc *p)
155{
156
157	if (syslogf)
158		FRELE(syslogf, p);
159	syslogf = NULL;
160	log_open = 0;
161	logsoftc.sc_state = 0;
162	return (0);
163}
164
165/*ARGSUSED*/
166int
167logread(dev_t dev, struct uio *uio, int flag)
168{
169	struct msgbuf *mbp = msgbufp;
170	long l;
171	int s;
172	int error = 0;
173
174	s = splhigh();
175	while (mbp->msg_bufr == mbp->msg_bufx) {
176		if (flag & IO_NDELAY) {
177			splx(s);
178			return (EWOULDBLOCK);
179		}
180		logsoftc.sc_state |= LOG_RDWAIT;
181		error = tsleep(mbp, LOG_RDPRI | PCATCH,
182			       "klog", 0);
183		if (error) {
184			splx(s);
185			return (error);
186		}
187	}
188	splx(s);
189	logsoftc.sc_state &= ~LOG_RDWAIT;
190
191	while (uio->uio_resid > 0) {
192		l = mbp->msg_bufx - mbp->msg_bufr;
193		if (l < 0)
194			l = mbp->msg_bufs - mbp->msg_bufr;
195		l = min(l, uio->uio_resid);
196		if (l == 0)
197			break;
198		error = uiomove(&mbp->msg_bufc[mbp->msg_bufr], (int)l, uio);
199		if (error)
200			break;
201		mbp->msg_bufr += l;
202		if (mbp->msg_bufr < 0 || mbp->msg_bufr >= mbp->msg_bufs)
203			mbp->msg_bufr = 0;
204	}
205	return (error);
206}
207
208/*ARGSUSED*/
209int
210logpoll(dev_t dev, int events, struct proc *p)
211{
212	int revents = 0;
213	int s = splhigh();
214
215	if (events & (POLLIN | POLLRDNORM)) {
216		if (msgbufp->msg_bufr != msgbufp->msg_bufx)
217			revents |= events & (POLLIN | POLLRDNORM);
218		else
219			selrecord(p, &logsoftc.sc_selp);
220	}
221	splx(s);
222	return (revents);
223}
224
225int
226logkqfilter(dev_t dev, struct knote *kn)
227{
228	struct klist *klist;
229	int s;
230
231	switch (kn->kn_filter) {
232	case EVFILT_READ:
233		klist = &logsoftc.sc_selp.si_note;
234		kn->kn_fop = &logread_filtops;
235		break;
236	default:
237		return (EINVAL);
238	}
239
240	kn->kn_hook = (void *)msgbufp;
241
242	s = splhigh();
243	SLIST_INSERT_HEAD(klist, kn, kn_selnext);
244	splx(s);
245
246	return (0);
247}
248
249void
250filt_logrdetach(struct knote *kn)
251{
252	int s = splhigh();
253
254	SLIST_REMOVE(&logsoftc.sc_selp.si_note, kn, knote, kn_selnext);
255	splx(s);
256}
257
258int
259filt_logread(struct knote *kn, long hint)
260{
261	struct  msgbuf *p = (struct  msgbuf *)kn->kn_hook;
262
263	kn->kn_data = (int)(p->msg_bufx - p->msg_bufr);
264
265	return (p->msg_bufx != p->msg_bufr);
266}
267
268void
269logwakeup(void)
270{
271	if (!log_open)
272		return;
273	selwakeup(&logsoftc.sc_selp);
274	if (logsoftc.sc_state & LOG_ASYNC)
275		csignal(logsoftc.sc_pgid, SIGIO,
276		    logsoftc.sc_siguid, logsoftc.sc_sigeuid);
277	if (logsoftc.sc_state & LOG_RDWAIT) {
278		wakeup(msgbufp);
279		logsoftc.sc_state &= ~LOG_RDWAIT;
280	}
281}
282
283/*ARGSUSED*/
284int
285logioctl(dev_t dev, u_long com, caddr_t data, int flag, struct proc *p)
286{
287	struct file *fp;
288	long l;
289	int error, s;
290
291	switch (com) {
292
293	/* return number of characters immediately available */
294	case FIONREAD:
295		s = splhigh();
296		l = msgbufp->msg_bufx - msgbufp->msg_bufr;
297		splx(s);
298		if (l < 0)
299			l += msgbufp->msg_bufs;
300		*(int *)data = l;
301		break;
302
303	case FIONBIO:
304		break;
305
306	case FIOASYNC:
307		if (*(int *)data)
308			logsoftc.sc_state |= LOG_ASYNC;
309		else
310			logsoftc.sc_state &= ~LOG_ASYNC;
311		break;
312
313	case TIOCSPGRP:
314		logsoftc.sc_pgid = *(int *)data;
315		logsoftc.sc_siguid = p->p_ucred->cr_ruid;
316		logsoftc.sc_sigeuid = p->p_ucred->cr_uid;
317		break;
318
319	case TIOCGPGRP:
320		*(int *)data = logsoftc.sc_pgid;
321		break;
322
323	case LIOCSFD:
324		if ((error = suser(p, 0)) != 0)
325			return (error);
326		if ((error = getsock(p->p_fd, *(int *)data, &fp)) != 0)
327			return (error);
328		if (syslogf)
329			FRELE(syslogf, p);
330		syslogf = fp;
331		break;
332
333	default:
334		return (ENOTTY);
335	}
336	return (0);
337}
338
339int
340sys_sendsyslog(struct proc *p, void *v, register_t *retval)
341{
342	struct sys_sendsyslog_args /* {
343		syscallarg(const void *) buf;
344		syscallarg(size_t) nbyte;
345	} */ *uap = v;
346#ifdef KTRACE
347	struct iovec *ktriov = NULL;
348#endif
349	struct iovec aiov;
350	struct uio auio;
351	struct file *f;
352	int error;
353
354	if (syslogf == NULL)
355		return (ENOTCONN);
356	f = syslogf;
357	FREF(f);
358
359	aiov.iov_base = (char *)SCARG(uap, buf);
360	aiov.iov_len = SCARG(uap, nbyte);
361	auio.uio_iov = &aiov;
362	auio.uio_iovcnt = 1;
363	auio.uio_segflg = UIO_USERSPACE;
364	auio.uio_rw = UIO_WRITE;
365	auio.uio_procp = p;
366	auio.uio_offset = 0;
367	auio.uio_resid = aiov.iov_len;
368#ifdef KTRACE
369	if (KTRPOINT(p, KTR_GENIO)) {
370		int iovlen = auio.uio_iovcnt * sizeof (struct iovec);
371
372		ktriov = malloc(iovlen, M_TEMP, M_WAITOK);
373		bcopy(auio.uio_iov, ktriov, iovlen);
374	}
375#endif
376
377	error = sosend(f->f_data, NULL, &auio, NULL, NULL, 0);
378
379#ifdef KTRACE
380	if (ktriov != NULL) {
381		if (error == 0)
382			ktrgenio(p, 0, UIO_WRITE, ktriov, aiov.iov_len);
383		free(ktriov, M_TEMP, 0);
384	}
385#endif
386	FRELE(f, p);
387	return error;
388}
389