1/*
2 * Copyright (c) 2000-2010 Apple, Inc. All rights reserved.
3 *
4 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
5 *
6 * This file contains Original Code and/or Modifications of Original Code
7 * as defined in and that are subject to the Apple Public Source License
8 * Version 2.0 (the 'License'). You may not use this file except in
9 * compliance with the License. The rights granted to you under the License
10 * may not be used to create, or enable the creation or redistribution of,
11 * unlawful or unlicensed copies of an Apple operating system, or to
12 * circumvent, violate, or enable the circumvention or violation of, any
13 * terms of an Apple operating system software license agreement.
14 *
15 * Please obtain a copy of the License at
16 * http://www.opensource.apple.com/apsl/ and read it before using this file.
17 *
18 * The Original Code and all software distributed under the License are
19 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
20 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
21 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
22 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
23 * Please see the License for the specific language governing rights and
24 * limitations under the License.
25 *
26 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
27 */
28/* Copyright (c) 1995 NeXT Computer, Inc. All Rights Reserved */
29/*
30 * Copyright (c) 1982, 1986, 1993
31 *	The Regents of the University of California.  All rights reserved.
32 *
33 * Redistribution and use in source and binary forms, with or without
34 * modification, are permitted provided that the following conditions
35 * are met:
36 * 1. Redistributions of source code must retain the above copyright
37 *    notice, this list of conditions and the following disclaimer.
38 * 2. Redistributions in binary form must reproduce the above copyright
39 *    notice, this list of conditions and the following disclaimer in the
40 *    documentation and/or other materials provided with the distribution.
41 * 3. All advertising materials mentioning features or use of this software
42 *    must display the following acknowledgement:
43 *	This product includes software developed by the University of
44 *	California, Berkeley and its contributors.
45 * 4. Neither the name of the University nor the names of its contributors
46 *    may be used to endorse or promote products derived from this software
47 *    without specific prior written permission.
48 *
49 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
50 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
51 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
52 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
53 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
54 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
55 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
56 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
57 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
58 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
59 * SUCH DAMAGE.
60 *
61 *	@(#)subr_log.c	8.3 (Berkeley) 2/14/95
62 */
63
64/*
65 * Error log buffer for kernel printf's.
66 */
67
68#include <sys/param.h>
69#include <sys/systm.h>
70#include <sys/proc_internal.h>
71#include <sys/vnode.h>
72#include <sys/ioctl.h>
73#include <sys/msgbuf.h>
74#include <sys/file_internal.h>
75#include <sys/errno.h>
76#include <sys/select.h>
77#include <sys/kernel.h>
78#include <kern/thread.h>
79#include <sys/lock.h>
80#include <sys/signalvar.h>
81#include <sys/conf.h>
82#include <sys/sysctl.h>
83#include <kern/kalloc.h>
84#include <pexpert/pexpert.h>
85
86/* XXX should be in a common header somewhere */
87extern void klogwakeup(void);
88extern void logwakeup(void);
89
90#define LOG_RDPRI	(PZERO + 1)
91
92#define LOG_NBIO	0x02
93#define LOG_ASYNC	0x04
94#define LOG_RDWAIT	0x08
95
96/* All globals should be accessed under LOG_LOCK() */
97
98/* logsoftc only valid while log_open=1 */
99struct logsoftc {
100	int	sc_state;		/* see above for possibilities */
101	struct	selinfo sc_selp;	/* thread waiting for select */
102	int	sc_pgid;		/* process/group for async I/O */
103} logsoftc;
104
105int	log_open;			/* also used in log() */
106char smsg_bufc[CONFIG_MSG_BSIZE]; /* static buffer */
107struct msgbuf msgbuf = {MSG_MAGIC,sizeof(smsg_bufc),0,0,smsg_bufc};
108struct msgbuf *msgbufp = &msgbuf;
109static int logentrypend = 0;
110
111/* the following are implemented in osfmk/kern/printf.c  */
112extern void bsd_log_lock(void);
113extern void bsd_log_unlock(void);
114extern void bsd_log_init(void);
115
116/* XXX wants a linker set so these can be static */
117extern d_open_t         logopen;
118extern d_close_t        logclose;
119extern d_read_t         logread;
120extern d_ioctl_t        logioctl;
121extern d_select_t       logselect;
122
123/*
124 * Serialize log access.  Note that the log can be written at interrupt level,
125 * so any log manipulations that can be done from, or affect, another processor
126 * at interrupt level must be guarded with a spin lock.
127 */
128
129#define	LOG_LOCK() bsd_log_lock()
130#define	LOG_UNLOCK() bsd_log_unlock()
131
132#if DEBUG
133#define LOG_SETSIZE_DEBUG(x...) kprintf(x)
134#else
135#define LOG_SETSIZE_DEBUG(x...) do { } while(0)
136#endif
137
138static int sysctl_kern_msgbuf(struct sysctl_oid *oidp,
139				void *arg1,
140				int arg2,
141				struct sysctl_req *req);
142
143/*ARGSUSED*/
144int
145logopen(__unused dev_t dev, __unused int flags, __unused int mode, struct proc *p)
146{
147	LOG_LOCK();
148	if (log_open) {
149		LOG_UNLOCK();
150		return (EBUSY);
151	}
152	logsoftc.sc_pgid = p->p_pid;		/* signal process only */
153	log_open = 1;
154
155	LOG_UNLOCK();
156
157	return (0);
158}
159
160/*ARGSUSED*/
161int
162logclose(__unused dev_t dev, __unused int flag, __unused int devtype, __unused struct proc *p)
163{
164	LOG_LOCK();
165	selwakeup(&logsoftc.sc_selp);
166	selthreadclear(&logsoftc.sc_selp);
167	log_open = 0;
168	LOG_UNLOCK();
169	return (0);
170}
171
172/*ARGSUSED*/
173int
174logread(__unused dev_t dev, struct uio *uio, int flag)
175{
176	int l;
177	int error = 0;
178
179	LOG_LOCK();
180	while (msgbufp->msg_bufr == msgbufp->msg_bufx) {
181		if (flag & IO_NDELAY) {
182			error = EWOULDBLOCK;
183			goto out;
184		}
185		if (logsoftc.sc_state & LOG_NBIO) {
186			error = EWOULDBLOCK;
187			goto out;
188		}
189		logsoftc.sc_state |= LOG_RDWAIT;
190		LOG_UNLOCK();
191		/*
192		 * If the wakeup is missed the ligtening bolt will wake this up
193		 * if there are any new characters. If that doesn't do it
194		 * then wait for 5 sec and reevaluate
195		 */
196		if ((error = tsleep((caddr_t)msgbufp, LOG_RDPRI | PCATCH,
197				"klog", 5 * hz)) != 0) {
198			/* if it times out; ignore */
199			if (error != EWOULDBLOCK)
200				return (error);
201		}
202		LOG_LOCK();
203	}
204	logsoftc.sc_state &= ~LOG_RDWAIT;
205
206	while (uio_resid(uio) > 0) {
207		int readpos;
208
209		l = msgbufp->msg_bufx - msgbufp->msg_bufr;
210		if (l < 0)
211			l = msgbufp->msg_size - msgbufp->msg_bufr;
212		l = min(l, uio_resid(uio));
213		if (l == 0)
214			break;
215
216		readpos = msgbufp->msg_bufr;
217		LOG_UNLOCK();
218		error = uiomove((caddr_t)&msgbufp->msg_bufc[readpos],
219			l, uio);
220		LOG_LOCK();
221		if (error)
222			break;
223		msgbufp->msg_bufr = readpos + l;
224		if (msgbufp->msg_bufr >= msgbufp->msg_size)
225			msgbufp->msg_bufr = 0;
226	}
227out:
228	LOG_UNLOCK();
229	return (error);
230}
231
232/*ARGSUSED*/
233int
234logselect(__unused dev_t dev, int rw, void * wql, struct proc *p)
235{
236	switch (rw) {
237
238	case FREAD:
239		LOG_LOCK();
240		if (msgbufp->msg_bufr != msgbufp->msg_bufx) {
241			LOG_UNLOCK();
242			return (1);
243		}
244		selrecord(p, &logsoftc.sc_selp, wql);
245		LOG_UNLOCK();
246		break;
247	}
248	return (0);
249}
250
251void
252logwakeup(void)
253{
254	int pgid;
255
256	LOG_LOCK();
257	if (!log_open) {
258		LOG_UNLOCK();
259		return;
260	}
261	selwakeup(&logsoftc.sc_selp);
262	if (logsoftc.sc_state & LOG_ASYNC) {
263		pgid = logsoftc.sc_pgid;
264		LOG_UNLOCK();
265		if (pgid < 0)
266			gsignal(-pgid, SIGIO);
267		else
268			proc_signal(pgid, SIGIO);
269		LOG_LOCK();
270	}
271	if (logsoftc.sc_state & LOG_RDWAIT) {
272		wakeup((caddr_t)msgbufp);
273		logsoftc.sc_state &= ~LOG_RDWAIT;
274	}
275	LOG_UNLOCK();
276}
277
278void
279klogwakeup(void)
280{
281	LOG_LOCK();
282	if (logentrypend && log_open) {
283		logentrypend = 0; /* only reset if someone will be reading */
284		LOG_UNLOCK();
285		logwakeup();
286	} else {
287		LOG_UNLOCK();
288	}
289}
290
291/*ARGSUSED*/
292int
293logioctl(__unused dev_t dev, u_long com, caddr_t data, __unused int flag, __unused struct proc *p)
294{
295	int l;
296
297	LOG_LOCK();
298	switch (com) {
299
300	/* return number of characters immediately available */
301	case FIONREAD:
302		l = msgbufp->msg_bufx - msgbufp->msg_bufr;
303		if (l < 0)
304			l += msgbufp->msg_size;
305		*(off_t *)data = l;
306		break;
307
308	case FIONBIO:
309		if (*(int *)data)
310			logsoftc.sc_state |= LOG_NBIO;
311		else
312			logsoftc.sc_state &= ~LOG_NBIO;
313		break;
314
315	case FIOASYNC:
316		if (*(int *)data)
317			logsoftc.sc_state |= LOG_ASYNC;
318		else
319			logsoftc.sc_state &= ~LOG_ASYNC;
320		break;
321
322	case TIOCSPGRP:
323		logsoftc.sc_pgid = *(int *)data;
324		break;
325
326	case TIOCGPGRP:
327		*(int *)data = logsoftc.sc_pgid;
328		break;
329
330	default:
331		LOG_UNLOCK();
332		return (-1);
333	}
334	LOG_UNLOCK();
335	return (0);
336}
337
338void
339bsd_log_init(void)
340{
341	/* After this point, we must be ready to accept characters */
342}
343
344
345/*
346 * log_putc_locked
347 *
348 * Decription:	Output a character to the log; assumes the LOG_LOCK() is held
349 *		by the caller.
350 *
351 * Parameters:	c				Character to output
352 *
353 * Returns:	(void)
354 *
355 * Notes:	This functions is used for multibyte output to the log; it
356 *		should be used preferrentially where possible to ensure that
357 *		log entries do not end up interspersed due to preemption or
358 *		SMP reentrancy.
359 */
360void
361log_putc_locked(char c)
362{
363	struct msgbuf *mbp;
364
365	mbp = msgbufp;
366	mbp->msg_bufc[mbp->msg_bufx++] = c;
367	logentrypend = 1;
368	if (mbp->msg_bufx >= msgbufp->msg_size)
369		mbp->msg_bufx = 0;
370}
371
372
373/*
374 * log_putc
375 *
376 * Decription:	Output a character to the log; assumes the LOG_LOCK() is NOT
377 *		held by the caller.
378 *
379 * Parameters:	c				Character to output
380 *
381 * Returns:	(void)
382 *
383 * Notes:	This function is used for syingle byte output to the log.  It
384 *		primarily exists to maintain binary backward compatibility.
385 */
386void
387log_putc(char c)
388{
389	LOG_LOCK();
390	log_putc_locked(c);
391	LOG_UNLOCK();
392}
393
394
395/*
396 * it is possible to increase the kernel log buffer size by adding
397 *   msgbuf=n
398 * to the kernel command line, and to read the current size using
399 *   sysctl kern.msgbuf
400 * If there is no parameter on the kernel command line, the buffer is
401 * allocated statically and is CONFIG_MSG_BSIZE characters in size, otherwise
402 * memory is dynamically allocated. Memory management must already be up.
403 */
404int
405log_setsize(int size) {
406	char *new_logdata;
407	int new_logsize, new_bufr, new_bufx;
408	char *old_logdata;
409	int old_logsize, old_bufr, old_bufx;
410	int i, count;
411	char *p, ch;
412
413	if (size > MAX_MSG_BSIZE)
414		return (EINVAL);
415
416	if (size <= 0)
417		return (EINVAL);
418
419	new_logsize = size;
420	if (!(new_logdata = (char*)kalloc(size))) {
421		printf("log_setsize: unable to allocate memory\n");
422		return (ENOMEM);
423	}
424	bzero(new_logdata, new_logsize);
425
426	LOG_LOCK();
427
428	old_logsize = msgbufp->msg_size;
429	old_logdata = msgbufp->msg_bufc;
430	old_bufr = msgbufp->msg_bufr;
431	old_bufx = msgbufp->msg_bufx;
432
433	LOG_SETSIZE_DEBUG("log_setsize(%d): old_logdata %p old_logsize %d old_bufr %d old_bufx %d\n",
434					  size, old_logdata, old_logsize, old_bufr, old_bufx);
435
436	/* start "new_logsize" bytes before the write pointer */
437	if (new_logsize <= old_bufx) {
438		count = new_logsize;
439		p = old_logdata + old_bufx - count;
440	} else {
441		/*
442		 * if new buffer is bigger, copy what we have and let the
443		 * bzero above handle the difference
444		 */
445		count = MIN(new_logsize, old_logsize);
446		p = old_logdata + old_logsize - (count - old_bufx);
447	}
448	for (i = 0; i < count; i++) {
449		if (p >= old_logdata + old_logsize)
450			p = old_logdata;
451
452		ch = *p++;
453		new_logdata[i] = ch;
454	}
455
456	new_bufx = i;
457	if (new_bufx >= new_logsize)
458		new_bufx = 0;
459	msgbufp->msg_bufx = new_bufx;
460
461	new_bufr = old_bufx - old_bufr; /* how much were we trailing bufx by? */
462	if (new_bufr < 0)
463		new_bufr += old_logsize;
464	new_bufr = new_bufx - new_bufr; /* now relative to oldest data in new buffer */
465	if (new_bufr < 0)
466		new_bufr += new_logsize;
467	msgbufp->msg_bufr = new_bufr;
468
469	msgbufp->msg_size = new_logsize;
470	msgbufp->msg_bufc = new_logdata;
471
472	LOG_SETSIZE_DEBUG("log_setsize(%d): new_logdata %p new_logsize %d new_bufr %d new_bufx %d\n",
473					  size, new_logdata, new_logsize, new_bufr, new_bufx);
474
475	LOG_UNLOCK();
476
477	/* this memory is now dead - clear it so that it compresses better
478	   in case of suspend to disk etc. */
479	bzero(old_logdata, old_logsize);
480	if (old_logdata != smsg_bufc) {
481		/* dynamic memory that must be freed */
482		kfree(old_logdata, old_logsize);
483	}
484
485	printf("set system log size to %d bytes\n", new_logsize);
486
487	return 0;
488}
489
490SYSCTL_PROC(_kern, OID_AUTO, msgbuf, CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_LOCKED, 0, 0, sysctl_kern_msgbuf, "I", "");
491
492static int sysctl_kern_msgbuf(struct sysctl_oid *oidp __unused,
493							  void *arg1 __unused,
494							  int arg2 __unused,
495							  struct sysctl_req *req)
496{
497	int old_bufsize, bufsize;
498	int error;
499
500	LOG_LOCK();
501	old_bufsize = bufsize = msgbufp->msg_size;
502	LOG_UNLOCK();
503
504	error = sysctl_io_number(req, bufsize, sizeof(bufsize), &bufsize, NULL);
505	if (error)
506		return (error);
507
508	if (bufsize != old_bufsize) {
509		error = log_setsize(bufsize);
510	}
511
512	return (error);
513}
514
515
516/*
517 * This should be called by /sbin/dmesg only via libproc.
518 * It returns as much data still in the buffer as possible.
519 */
520int
521log_dmesg(user_addr_t buffer, uint32_t buffersize, int32_t * retval) {
522	uint32_t i;
523	uint32_t localbuff_size;
524	int error = 0, newl, skip;
525	char *localbuff, *p, *copystart, ch;
526	size_t copysize;
527
528	LOG_LOCK();
529	localbuff_size = (msgbufp->msg_size + 2); /* + '\n' + '\0' */
530	LOG_UNLOCK();
531
532	/* Allocate a temporary non-circular buffer for copyout */
533	if (!(localbuff = (char *)kalloc(localbuff_size))) {
534		printf("log_dmesg: unable to allocate memory\n");
535		return (ENOMEM);
536	}
537
538	/* in between here, the log could become bigger, but that's fine */
539	LOG_LOCK();
540
541	/*
542	 * The message buffer is circular; start at the write pointer, and
543	 * make one loop up to write pointer - 1.
544	 */
545	p = msgbufp->msg_bufc + msgbufp->msg_bufx;
546	for (i = newl = skip = 0; p != msgbufp->msg_bufc + msgbufp->msg_bufx - 1; ++p) {
547		if (p >= msgbufp->msg_bufc + msgbufp->msg_size)
548			p = msgbufp->msg_bufc;
549		ch = *p;
550		/* Skip "\n<.*>" syslog sequences. */
551		if (skip) {
552			if (ch == '>')
553				newl = skip = 0;
554			continue;
555		}
556		if (newl && ch == '<') {
557			skip = 1;
558			continue;
559		}
560		if (ch == '\0')
561			continue;
562		newl = (ch == '\n');
563		localbuff[i++] = ch;
564		/* The original version of this routine contained a buffer
565		 * overflow. At the time, a "small" targeted fix was desired
566		 * so the change below to check the buffer bounds was made.
567		 * TODO: rewrite this needlessly convoluted routine.
568		 */
569		if (i == (localbuff_size - 2))
570			break;
571	}
572	if (!newl)
573		localbuff[i++] = '\n';
574	localbuff[i++] = 0;
575
576	if (buffersize >= i) {
577		copystart = localbuff;
578		copysize = i;
579	} else {
580		copystart = localbuff + i - buffersize;
581		copysize = buffersize;
582	}
583
584	LOG_UNLOCK();
585
586	error = copyout(copystart, buffer, copysize);
587	if (!error)
588		*retval = copysize;
589
590	kfree(localbuff, localbuff_size);
591	return (error);
592}
593