subr_log.c revision 1.27 
1/*	$OpenBSD: subr_log.c,v 1.27 2015/01/13 18:51:27 kettenis 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 */
77struct	msgbuf *msgbufp;		/* the mapped buffer, itself. */
78struct	msgbuf *consbufp;		/* console message buffer. */
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(msgbufp, '\n');
117
118	/* mark it as ready for use. */
119	msgbufmapped = 1;
120}
121
122void
123initconsbuf(void)
124{
125	long new_bufs;
126
127	/* Set up a buffer to collect /dev/console output */
128	consbufp = malloc(CONSBUFSIZE, M_TEMP, M_NOWAIT|M_ZERO);
129	if (consbufp) {
130		new_bufs = CONSBUFSIZE - offsetof(struct msgbuf, msg_bufc);
131		consbufp->msg_magic = MSG_MAGIC;
132		consbufp->msg_bufs = new_bufs;
133	}
134}
135
136void
137msgbuf_putchar(struct msgbuf *mbp, const char c)
138{
139	if (mbp->msg_magic != MSG_MAGIC)
140		/* Nothing we can do */
141		return;
142
143	mbp->msg_bufc[mbp->msg_bufx++] = c;
144	mbp->msg_bufl = min(mbp->msg_bufl+1, mbp->msg_bufs);
145	if (mbp->msg_bufx < 0 || mbp->msg_bufx >= mbp->msg_bufs)
146		mbp->msg_bufx = 0;
147	/* If the buffer is full, keep the most recent data. */
148	if (mbp->msg_bufr == mbp->msg_bufx) {
149		if (++mbp->msg_bufr >= mbp->msg_bufs)
150			mbp->msg_bufr = 0;
151	}
152}
153
154/*ARGSUSED*/
155int
156logopen(dev_t dev, int flags, int mode, struct proc *p)
157{
158	if (log_open)
159		return (EBUSY);
160	log_open = 1;
161	return (0);
162}
163
164/*ARGSUSED*/
165int
166logclose(dev_t dev, int flag, int mode, struct proc *p)
167{
168
169	if (syslogf)
170		FRELE(syslogf, p);
171	syslogf = NULL;
172	log_open = 0;
173	logsoftc.sc_state = 0;
174	return (0);
175}
176
177/*ARGSUSED*/
178int
179logread(dev_t dev, struct uio *uio, int flag)
180{
181	struct msgbuf *mbp = msgbufp;
182	long l;
183	int s;
184	int error = 0;
185
186	s = splhigh();
187	while (mbp->msg_bufr == mbp->msg_bufx) {
188		if (flag & IO_NDELAY) {
189			splx(s);
190			return (EWOULDBLOCK);
191		}
192		logsoftc.sc_state |= LOG_RDWAIT;
193		error = tsleep(mbp, LOG_RDPRI | PCATCH,
194			       "klog", 0);
195		if (error) {
196			splx(s);
197			return (error);
198		}
199	}
200	splx(s);
201	logsoftc.sc_state &= ~LOG_RDWAIT;
202
203	while (uio->uio_resid > 0) {
204		l = mbp->msg_bufx - mbp->msg_bufr;
205		if (l < 0)
206			l = mbp->msg_bufs - mbp->msg_bufr;
207		l = min(l, uio->uio_resid);
208		if (l == 0)
209			break;
210		error = uiomove(&mbp->msg_bufc[mbp->msg_bufr], (int)l, uio);
211		if (error)
212			break;
213		mbp->msg_bufr += l;
214		if (mbp->msg_bufr < 0 || mbp->msg_bufr >= mbp->msg_bufs)
215			mbp->msg_bufr = 0;
216	}
217	return (error);
218}
219
220/*ARGSUSED*/
221int
222logpoll(dev_t dev, int events, struct proc *p)
223{
224	int revents = 0;
225	int s = splhigh();
226
227	if (events & (POLLIN | POLLRDNORM)) {
228		if (msgbufp->msg_bufr != msgbufp->msg_bufx)
229			revents |= events & (POLLIN | POLLRDNORM);
230		else
231			selrecord(p, &logsoftc.sc_selp);
232	}
233	splx(s);
234	return (revents);
235}
236
237int
238logkqfilter(dev_t dev, struct knote *kn)
239{
240	struct klist *klist;
241	int s;
242
243	switch (kn->kn_filter) {
244	case EVFILT_READ:
245		klist = &logsoftc.sc_selp.si_note;
246		kn->kn_fop = &logread_filtops;
247		break;
248	default:
249		return (EINVAL);
250	}
251
252	kn->kn_hook = (void *)msgbufp;
253
254	s = splhigh();
255	SLIST_INSERT_HEAD(klist, kn, kn_selnext);
256	splx(s);
257
258	return (0);
259}
260
261void
262filt_logrdetach(struct knote *kn)
263{
264	int s = splhigh();
265
266	SLIST_REMOVE(&logsoftc.sc_selp.si_note, kn, knote, kn_selnext);
267	splx(s);
268}
269
270int
271filt_logread(struct knote *kn, long hint)
272{
273	struct  msgbuf *p = (struct  msgbuf *)kn->kn_hook;
274
275	kn->kn_data = (int)(p->msg_bufx - p->msg_bufr);
276
277	return (p->msg_bufx != p->msg_bufr);
278}
279
280void
281logwakeup(void)
282{
283	if (!log_open)
284		return;
285	selwakeup(&logsoftc.sc_selp);
286	if (logsoftc.sc_state & LOG_ASYNC)
287		csignal(logsoftc.sc_pgid, SIGIO,
288		    logsoftc.sc_siguid, logsoftc.sc_sigeuid);
289	if (logsoftc.sc_state & LOG_RDWAIT) {
290		wakeup(msgbufp);
291		logsoftc.sc_state &= ~LOG_RDWAIT;
292	}
293}
294
295/*ARGSUSED*/
296int
297logioctl(dev_t dev, u_long com, caddr_t data, int flag, struct proc *p)
298{
299	struct file *fp;
300	long l;
301	int error, s;
302
303	switch (com) {
304
305	/* return number of characters immediately available */
306	case FIONREAD:
307		s = splhigh();
308		l = msgbufp->msg_bufx - msgbufp->msg_bufr;
309		splx(s);
310		if (l < 0)
311			l += msgbufp->msg_bufs;
312		*(int *)data = l;
313		break;
314
315	case FIONBIO:
316		break;
317
318	case FIOASYNC:
319		if (*(int *)data)
320			logsoftc.sc_state |= LOG_ASYNC;
321		else
322			logsoftc.sc_state &= ~LOG_ASYNC;
323		break;
324
325	case TIOCSPGRP:
326		logsoftc.sc_pgid = *(int *)data;
327		logsoftc.sc_siguid = p->p_ucred->cr_ruid;
328		logsoftc.sc_sigeuid = p->p_ucred->cr_uid;
329		break;
330
331	case TIOCGPGRP:
332		*(int *)data = logsoftc.sc_pgid;
333		break;
334
335	case LIOCSFD:
336		if ((error = suser(p, 0)) != 0)
337			return (error);
338		if ((error = getsock(p->p_fd, *(int *)data, &fp)) != 0)
339			return (error);
340		if (syslogf)
341			FRELE(syslogf, p);
342		syslogf = fp;
343		break;
344
345	default:
346		return (ENOTTY);
347	}
348	return (0);
349}
350
351int
352sys_sendsyslog(struct proc *p, void *v, register_t *retval)
353{
354	struct sys_sendsyslog_args /* {
355		syscallarg(const void *) buf;
356		syscallarg(size_t) nbyte;
357	} */ *uap = v;
358#ifdef KTRACE
359	struct iovec *ktriov = NULL;
360	int iovlen;
361#endif
362	struct iovec aiov;
363	struct uio auio;
364	struct file *f;
365	size_t len;
366	int error;
367
368	if (syslogf == NULL)
369		return (ENOTCONN);
370	f = syslogf;
371	FREF(f);
372
373	aiov.iov_base = (char *)SCARG(uap, buf);
374	aiov.iov_len = SCARG(uap, nbyte);
375	auio.uio_iov = &aiov;
376	auio.uio_iovcnt = 1;
377	auio.uio_segflg = UIO_USERSPACE;
378	auio.uio_rw = UIO_WRITE;
379	auio.uio_procp = p;
380	auio.uio_offset = 0;
381	auio.uio_resid = aiov.iov_len;
382#ifdef KTRACE
383	if (KTRPOINT(p, KTR_GENIO)) {
384		ktriov = mallocarray(auio.uio_iovcnt, sizeof(struct iovec),
385		    M_TEMP, M_WAITOK);
386		iovlen = auio.uio_iovcnt * sizeof (struct iovec);
387
388		memcpy(ktriov, auio.uio_iov, iovlen);
389	}
390#endif
391
392	len = auio.uio_resid;
393	error = sosend(f->f_data, NULL, &auio, NULL, NULL, 0);
394	if (error == 0)
395		len -= auio.uio_resid;
396
397#ifdef KTRACE
398	if (ktriov != NULL) {
399		if (error == 0)
400			ktrgenio(p, -1, UIO_WRITE, ktriov, len);
401		free(ktriov, M_TEMP, iovlen);
402	}
403#endif
404	FRELE(f, p);
405	return error;
406}
407