subr_log.c revision 1.42 
1/*	$OpenBSD: subr_log.c,v 1.42 2016/05/18 23:28:43 bluhm 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/tty.h>
47#include <sys/signalvar.h>
48#include <sys/syslog.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#include <dev/cons.h>
63
64#define LOG_RDPRI	(PZERO + 1)
65
66#define LOG_ASYNC	0x04
67#define LOG_RDWAIT	0x08
68
69struct logsoftc {
70	int	sc_state;		/* see above for possibilities */
71	struct	selinfo sc_selp;	/* process waiting on select call */
72	int	sc_pgid;		/* process/group for async I/O */
73	uid_t	sc_siguid;		/* uid for process that set sc_pgid */
74	uid_t	sc_sigeuid;		/* euid for process that set sc_pgid */
75} logsoftc;
76
77int	log_open;			/* also used in log() */
78int	msgbufmapped;			/* is the message buffer mapped */
79struct	msgbuf *msgbufp;		/* the mapped buffer, itself. */
80struct	msgbuf *consbufp;		/* console message buffer. */
81struct	file *syslogf;
82
83void filt_logrdetach(struct knote *kn);
84int filt_logread(struct knote *kn, long hint);
85
86struct filterops logread_filtops =
87	{ 1, NULL, filt_logrdetach, filt_logread};
88
89int dosendsyslog(struct proc *, const char *, size_t, int, enum uio_seg);
90
91void
92initmsgbuf(caddr_t buf, size_t bufsize)
93{
94	struct msgbuf *mbp;
95	long new_bufs;
96
97	/* Sanity-check the given size. */
98	if (bufsize < sizeof(struct msgbuf))
99		return;
100
101	mbp = msgbufp = (struct msgbuf *)buf;
102
103	new_bufs = bufsize - offsetof(struct msgbuf, msg_bufc);
104	if ((mbp->msg_magic != MSG_MAGIC) || (mbp->msg_bufs != new_bufs) ||
105	    (mbp->msg_bufr < 0) || (mbp->msg_bufr >= mbp->msg_bufs) ||
106	    (mbp->msg_bufx < 0) || (mbp->msg_bufx >= mbp->msg_bufs)) {
107		/*
108		 * If the buffer magic number is wrong, has changed
109		 * size (which shouldn't happen often), or is
110		 * internally inconsistent, initialize it.
111		 */
112
113		memset(buf, 0, bufsize);
114		mbp->msg_magic = MSG_MAGIC;
115		mbp->msg_bufs = new_bufs;
116	}
117
118	/* Always start new buffer data on a new line. */
119	if (mbp->msg_bufx > 0 && mbp->msg_bufc[mbp->msg_bufx - 1] != '\n')
120		msgbuf_putchar(msgbufp, '\n');
121
122	/* mark it as ready for use. */
123	msgbufmapped = 1;
124}
125
126void
127initconsbuf(void)
128{
129	long new_bufs;
130
131	/* Set up a buffer to collect /dev/console output */
132	consbufp = malloc(CONSBUFSIZE, M_TEMP, M_NOWAIT|M_ZERO);
133	if (consbufp) {
134		new_bufs = CONSBUFSIZE - offsetof(struct msgbuf, msg_bufc);
135		consbufp->msg_magic = MSG_MAGIC;
136		consbufp->msg_bufs = new_bufs;
137	}
138}
139
140void
141msgbuf_putchar(struct msgbuf *mbp, const char c)
142{
143	if (mbp->msg_magic != MSG_MAGIC)
144		/* Nothing we can do */
145		return;
146
147	mbp->msg_bufc[mbp->msg_bufx++] = c;
148	mbp->msg_bufl = min(mbp->msg_bufl+1, mbp->msg_bufs);
149	if (mbp->msg_bufx < 0 || mbp->msg_bufx >= mbp->msg_bufs)
150		mbp->msg_bufx = 0;
151	/* If the buffer is full, keep the most recent data. */
152	if (mbp->msg_bufr == mbp->msg_bufx) {
153		if (++mbp->msg_bufr >= mbp->msg_bufs)
154			mbp->msg_bufr = 0;
155	}
156}
157
158int
159logopen(dev_t dev, int flags, int mode, struct proc *p)
160{
161	if (log_open)
162		return (EBUSY);
163	log_open = 1;
164	return (0);
165}
166
167int
168logclose(dev_t dev, int flag, int mode, struct proc *p)
169{
170
171	if (syslogf)
172		FRELE(syslogf, p);
173	syslogf = NULL;
174	log_open = 0;
175	logsoftc.sc_state = 0;
176	return (0);
177}
178
179int
180logread(dev_t dev, struct uio *uio, int flag)
181{
182	struct msgbuf *mbp = msgbufp;
183	size_t l;
184	int s;
185	int error = 0;
186
187	s = splhigh();
188	while (mbp->msg_bufr == mbp->msg_bufx) {
189		if (flag & IO_NDELAY) {
190			splx(s);
191			return (EWOULDBLOCK);
192		}
193		logsoftc.sc_state |= LOG_RDWAIT;
194		error = tsleep(mbp, LOG_RDPRI | PCATCH,
195			       "klog", 0);
196		if (error) {
197			splx(s);
198			return (error);
199		}
200	}
201	splx(s);
202	logsoftc.sc_state &= ~LOG_RDWAIT;
203
204	while (uio->uio_resid > 0) {
205		if (mbp->msg_bufx >= mbp->msg_bufr)
206			l = mbp->msg_bufx - mbp->msg_bufr;
207		else
208			l = mbp->msg_bufs - mbp->msg_bufr;
209		l = ulmin(l, uio->uio_resid);
210		if (l == 0)
211			break;
212		error = uiomove(&mbp->msg_bufc[mbp->msg_bufr], l, uio);
213		if (error)
214			break;
215		mbp->msg_bufr += l;
216		if (mbp->msg_bufr < 0 || mbp->msg_bufr >= mbp->msg_bufs)
217			mbp->msg_bufr = 0;
218	}
219	return (error);
220}
221
222int
223logpoll(dev_t dev, int events, struct proc *p)
224{
225	int revents = 0;
226	int s = splhigh();
227
228	if (events & (POLLIN | POLLRDNORM)) {
229		if (msgbufp->msg_bufr != msgbufp->msg_bufx)
230			revents |= events & (POLLIN | POLLRDNORM);
231		else
232			selrecord(p, &logsoftc.sc_selp);
233	}
234	splx(s);
235	return (revents);
236}
237
238int
239logkqfilter(dev_t dev, struct knote *kn)
240{
241	struct klist *klist;
242	int s;
243
244	switch (kn->kn_filter) {
245	case EVFILT_READ:
246		klist = &logsoftc.sc_selp.si_note;
247		kn->kn_fop = &logread_filtops;
248		break;
249	default:
250		return (EINVAL);
251	}
252
253	kn->kn_hook = (void *)msgbufp;
254
255	s = splhigh();
256	SLIST_INSERT_HEAD(klist, kn, kn_selnext);
257	splx(s);
258
259	return (0);
260}
261
262void
263filt_logrdetach(struct knote *kn)
264{
265	int s = splhigh();
266
267	SLIST_REMOVE(&logsoftc.sc_selp.si_note, kn, knote, kn_selnext);
268	splx(s);
269}
270
271int
272filt_logread(struct knote *kn, long hint)
273{
274	struct  msgbuf *p = (struct  msgbuf *)kn->kn_hook;
275
276	kn->kn_data = (int)(p->msg_bufx - p->msg_bufr);
277
278	return (p->msg_bufx != p->msg_bufr);
279}
280
281void
282logwakeup(void)
283{
284	if (!log_open)
285		return;
286	selwakeup(&logsoftc.sc_selp);
287	if (logsoftc.sc_state & LOG_ASYNC)
288		csignal(logsoftc.sc_pgid, SIGIO,
289		    logsoftc.sc_siguid, logsoftc.sc_sigeuid);
290	if (logsoftc.sc_state & LOG_RDWAIT) {
291		wakeup(msgbufp);
292		logsoftc.sc_state &= ~LOG_RDWAIT;
293	}
294}
295
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, *(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_osendsyslog(struct proc *p, void *v, register_t *retval)
353{
354	struct sys_osendsyslog_args /* {
355		syscallarg(const void *) buf;
356		syscallarg(size_t) nbyte;
357	} */ *uap = v;
358	struct sys_sendsyslog_args oap;
359
360	SCARG(&oap, buf) = SCARG(uap, buf);
361	SCARG(&oap, nbyte) = SCARG(uap, nbyte);
362	SCARG(&oap, flags) = 0;
363	return sys_sendsyslog(p, &oap, retval);
364}
365
366int
367sys_sendsyslog(struct proc *p, void *v, register_t *retval)
368{
369	struct sys_sendsyslog_args /* {
370		syscallarg(const void *) buf;
371		syscallarg(size_t) nbyte;
372		syscallarg(int) flags;
373	} */ *uap = v;
374	int error;
375#ifndef SMALL_KERNEL
376	static int dropped_count, orig_error;
377	int len;
378	char buf[64];
379
380	if (dropped_count) {
381		len = snprintf(buf, sizeof(buf),
382		    "<%d>sendsyslog: dropped %d message%s, error %d",
383		    LOG_KERN|LOG_WARNING, dropped_count,
384		    dropped_count == 1 ? "" : "s", orig_error);
385		error = dosendsyslog(p, buf, MIN((size_t)len, sizeof(buf) - 1),
386		    0, UIO_SYSSPACE);
387		if (error == 0)
388			dropped_count = 0;
389	}
390#endif
391	error = dosendsyslog(p, SCARG(uap, buf), SCARG(uap, nbyte),
392	    SCARG(uap, flags), UIO_USERSPACE);
393#ifndef SMALL_KERNEL
394	if (error) {
395		dropped_count++;
396		orig_error = error;
397	}
398#endif
399	return (error);
400}
401
402int
403dosendsyslog(struct proc *p, const char *buf, size_t nbyte, int flags,
404    enum uio_seg sflg)
405{
406#ifdef KTRACE
407	struct iovec *ktriov = NULL;
408	int iovlen;
409#endif
410	char pri[6], *kbuf;
411	struct iovec aiov;
412	struct uio auio;
413	size_t i, len;
414	int error;
415
416	if (syslogf)
417		FREF(syslogf);
418	else if (!ISSET(flags, LOG_CONS))
419		return (ENOTCONN);
420	else {
421		/*
422		 * Strip off syslog priority when logging to console.
423		 * LOG_PRIMASK | LOG_FACMASK is 0x03ff, so at most 4
424		 * decimal digits may appear in priority as <1023>.
425		 */
426		len = MIN(nbyte, sizeof(pri));
427		if (sflg == UIO_USERSPACE) {
428			if ((error = copyin(buf, pri, len)))
429				return (error);
430		} else
431			memcpy(pri, buf, len);
432		if (0 < len && pri[0] == '<') {
433			for (i = 1; i < len; i++) {
434				if (pri[i] < '0' || pri[i] > '9')
435					break;
436			}
437			if (i < len && pri[i] == '>') {
438				i++;
439				/* There must be at least one digit <0>. */
440				if (i >= 3) {
441					buf += i;
442					nbyte -= i;
443				}
444			}
445		}
446	}
447
448	aiov.iov_base = (char *)buf;
449	aiov.iov_len = nbyte;
450	auio.uio_iov = &aiov;
451	auio.uio_iovcnt = 1;
452	auio.uio_segflg = sflg;
453	auio.uio_rw = UIO_WRITE;
454	auio.uio_procp = p;
455	auio.uio_offset = 0;
456	auio.uio_resid = aiov.iov_len;
457#ifdef KTRACE
458	if (KTRPOINT(p, KTR_GENIO)) {
459		ktriov = mallocarray(auio.uio_iovcnt, sizeof(struct iovec),
460		    M_TEMP, M_WAITOK);
461		iovlen = auio.uio_iovcnt * sizeof (struct iovec);
462
463		memcpy(ktriov, auio.uio_iov, iovlen);
464	}
465#endif
466
467	len = auio.uio_resid;
468	if (syslogf) {
469		error = sosend(syslogf->f_data, NULL, &auio, NULL, NULL, 0);
470		if (error == 0)
471			len -= auio.uio_resid;
472	} else if (constty || cn_devvp) {
473		error = cnwrite(0, &auio, 0);
474		if (error == 0)
475			len -= auio.uio_resid;
476		aiov.iov_base = "\r\n";
477		aiov.iov_len = 2;
478		auio.uio_iov = &aiov;
479		auio.uio_iovcnt = 1;
480		auio.uio_segflg = UIO_SYSSPACE;
481		auio.uio_rw = UIO_WRITE;
482		auio.uio_procp = p;
483		auio.uio_offset = 0;
484		auio.uio_resid = aiov.iov_len;
485		cnwrite(0, &auio, 0);
486	} else {
487		/* XXX console redirection breaks down... */
488		if (sflg == UIO_USERSPACE) {
489			kbuf = malloc(len, M_TEMP, M_WAITOK);
490			error = copyin(aiov.iov_base, kbuf, len);
491		} else {
492			kbuf = aiov.iov_base;
493			error = 0;
494		}
495		if (error == 0)
496			for (i = 0; i < len; i++) {
497				if (kbuf[i] == '\0')
498					break;
499				cnputc(kbuf[i]);
500				auio.uio_resid--;
501			}
502		if (sflg == UIO_USERSPACE)
503			free(kbuf, M_TEMP, len);
504		if (error == 0)
505			len -= auio.uio_resid;
506		cnputc('\n');
507	}
508
509#ifdef KTRACE
510	if (ktriov != NULL) {
511		if (error == 0)
512			ktrgenio(p, -1, UIO_WRITE, ktriov, len);
513		free(ktriov, M_TEMP, iovlen);
514	}
515#endif
516	if (syslogf)
517		FRELE(syslogf, p);
518	else
519		error = ENOTCONN;
520	return (error);
521}
522