log.c revision 323124 
1/* $OpenBSD: log.c,v 1.48 2016/07/15 05:01:58 dtucker Exp $ */
2/*
3 * Author: Tatu Ylonen <ylo@cs.hut.fi>
4 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
5 *                    All rights reserved
6 *
7 * As far as I am concerned, the code I have written for this software
8 * can be used freely for any purpose.  Any derived versions of this
9 * software must be clearly marked as such, and if the derived work is
10 * incompatible with the protocol description in the RFC file, it must be
11 * called by a name other than "ssh" or "Secure Shell".
12 */
13/*
14 * Copyright (c) 2000 Markus Friedl.  All rights reserved.
15 *
16 * Redistribution and use in source and binary forms, with or without
17 * modification, are permitted provided that the following conditions
18 * are met:
19 * 1. Redistributions of source code must retain the above copyright
20 *    notice, this list of conditions and the following disclaimer.
21 * 2. Redistributions in binary form must reproduce the above copyright
22 *    notice, this list of conditions and the following disclaimer in the
23 *    documentation and/or other materials provided with the distribution.
24 *
25 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
26 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
27 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
28 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
29 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
30 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
31 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
32 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
33 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
34 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
35 */
36
37#include "includes.h"
38
39#include <sys/types.h>
40
41#include <fcntl.h>
42#include <stdarg.h>
43#include <stdio.h>
44#include <stdlib.h>
45#include <string.h>
46#include <syslog.h>
47#include <unistd.h>
48#include <errno.h>
49#if defined(HAVE_STRNVIS) && defined(HAVE_VIS_H) && !defined(BROKEN_STRNVIS)
50# include <vis.h>
51#endif
52
53#include "log.h"
54
55static LogLevel log_level = SYSLOG_LEVEL_INFO;
56static int log_on_stderr = 1;
57static int log_stderr_fd = STDERR_FILENO;
58static int log_facility = LOG_AUTH;
59static char *argv0;
60static log_handler_fn *log_handler;
61static void *log_handler_ctx;
62
63extern char *__progname;
64
65#define LOG_SYSLOG_VIS	(VIS_CSTYLE|VIS_NL|VIS_TAB|VIS_OCTAL)
66#define LOG_STDERR_VIS	(VIS_SAFE|VIS_OCTAL)
67
68/* textual representation of log-facilities/levels */
69
70static struct {
71	const char *name;
72	SyslogFacility val;
73} log_facilities[] = {
74	{ "DAEMON",	SYSLOG_FACILITY_DAEMON },
75	{ "USER",	SYSLOG_FACILITY_USER },
76	{ "AUTH",	SYSLOG_FACILITY_AUTH },
77#ifdef LOG_AUTHPRIV
78	{ "AUTHPRIV",	SYSLOG_FACILITY_AUTHPRIV },
79#endif
80	{ "LOCAL0",	SYSLOG_FACILITY_LOCAL0 },
81	{ "LOCAL1",	SYSLOG_FACILITY_LOCAL1 },
82	{ "LOCAL2",	SYSLOG_FACILITY_LOCAL2 },
83	{ "LOCAL3",	SYSLOG_FACILITY_LOCAL3 },
84	{ "LOCAL4",	SYSLOG_FACILITY_LOCAL4 },
85	{ "LOCAL5",	SYSLOG_FACILITY_LOCAL5 },
86	{ "LOCAL6",	SYSLOG_FACILITY_LOCAL6 },
87	{ "LOCAL7",	SYSLOG_FACILITY_LOCAL7 },
88	{ NULL,		SYSLOG_FACILITY_NOT_SET }
89};
90
91static struct {
92	const char *name;
93	LogLevel val;
94} log_levels[] =
95{
96	{ "QUIET",	SYSLOG_LEVEL_QUIET },
97	{ "FATAL",	SYSLOG_LEVEL_FATAL },
98	{ "ERROR",	SYSLOG_LEVEL_ERROR },
99	{ "INFO",	SYSLOG_LEVEL_INFO },
100	{ "VERBOSE",	SYSLOG_LEVEL_VERBOSE },
101	{ "DEBUG",	SYSLOG_LEVEL_DEBUG1 },
102	{ "DEBUG1",	SYSLOG_LEVEL_DEBUG1 },
103	{ "DEBUG2",	SYSLOG_LEVEL_DEBUG2 },
104	{ "DEBUG3",	SYSLOG_LEVEL_DEBUG3 },
105	{ NULL,		SYSLOG_LEVEL_NOT_SET }
106};
107
108SyslogFacility
109log_facility_number(char *name)
110{
111	int i;
112
113	if (name != NULL)
114		for (i = 0; log_facilities[i].name; i++)
115			if (strcasecmp(log_facilities[i].name, name) == 0)
116				return log_facilities[i].val;
117	return SYSLOG_FACILITY_NOT_SET;
118}
119
120const char *
121log_facility_name(SyslogFacility facility)
122{
123	u_int i;
124
125	for (i = 0;  log_facilities[i].name; i++)
126		if (log_facilities[i].val == facility)
127			return log_facilities[i].name;
128	return NULL;
129}
130
131LogLevel
132log_level_number(char *name)
133{
134	int i;
135
136	if (name != NULL)
137		for (i = 0; log_levels[i].name; i++)
138			if (strcasecmp(log_levels[i].name, name) == 0)
139				return log_levels[i].val;
140	return SYSLOG_LEVEL_NOT_SET;
141}
142
143const char *
144log_level_name(LogLevel level)
145{
146	u_int i;
147
148	for (i = 0; log_levels[i].name != NULL; i++)
149		if (log_levels[i].val == level)
150			return log_levels[i].name;
151	return NULL;
152}
153
154/* Error messages that should be logged. */
155
156void
157error(const char *fmt,...)
158{
159	va_list args;
160
161	va_start(args, fmt);
162	do_log(SYSLOG_LEVEL_ERROR, fmt, args);
163	va_end(args);
164}
165
166void
167sigdie(const char *fmt,...)
168{
169#ifdef DO_LOG_SAFE_IN_SIGHAND
170	va_list args;
171
172	va_start(args, fmt);
173	do_log(SYSLOG_LEVEL_FATAL, fmt, args);
174	va_end(args);
175#endif
176	_exit(1);
177}
178
179void
180logdie(const char *fmt,...)
181{
182	va_list args;
183
184	va_start(args, fmt);
185	do_log(SYSLOG_LEVEL_INFO, fmt, args);
186	va_end(args);
187	cleanup_exit(255);
188}
189
190/* Log this message (information that usually should go to the log). */
191
192void
193logit(const char *fmt,...)
194{
195	va_list args;
196
197	va_start(args, fmt);
198	do_log(SYSLOG_LEVEL_INFO, fmt, args);
199	va_end(args);
200}
201
202/* More detailed messages (information that does not need to go to the log). */
203
204void
205verbose(const char *fmt,...)
206{
207	va_list args;
208
209	va_start(args, fmt);
210	do_log(SYSLOG_LEVEL_VERBOSE, fmt, args);
211	va_end(args);
212}
213
214/* Debugging messages that should not be logged during normal operation. */
215
216void
217debug(const char *fmt,...)
218{
219	va_list args;
220
221	va_start(args, fmt);
222	do_log(SYSLOG_LEVEL_DEBUG1, fmt, args);
223	va_end(args);
224}
225
226void
227debug2(const char *fmt,...)
228{
229	va_list args;
230
231	va_start(args, fmt);
232	do_log(SYSLOG_LEVEL_DEBUG2, fmt, args);
233	va_end(args);
234}
235
236void
237debug3(const char *fmt,...)
238{
239	va_list args;
240
241	va_start(args, fmt);
242	do_log(SYSLOG_LEVEL_DEBUG3, fmt, args);
243	va_end(args);
244}
245
246/*
247 * Initialize the log.
248 */
249
250void
251log_init(char *av0, LogLevel level, SyslogFacility facility, int on_stderr)
252{
253#if defined(HAVE_OPENLOG_R) && defined(SYSLOG_DATA_INIT)
254	struct syslog_data sdata = SYSLOG_DATA_INIT;
255#endif
256
257	argv0 = av0;
258
259	switch (level) {
260	case SYSLOG_LEVEL_QUIET:
261	case SYSLOG_LEVEL_FATAL:
262	case SYSLOG_LEVEL_ERROR:
263	case SYSLOG_LEVEL_INFO:
264	case SYSLOG_LEVEL_VERBOSE:
265	case SYSLOG_LEVEL_DEBUG1:
266	case SYSLOG_LEVEL_DEBUG2:
267	case SYSLOG_LEVEL_DEBUG3:
268		log_level = level;
269		break;
270	default:
271		fprintf(stderr, "Unrecognized internal syslog level code %d\n",
272		    (int) level);
273		exit(1);
274	}
275
276	log_handler = NULL;
277	log_handler_ctx = NULL;
278
279	log_on_stderr = on_stderr;
280	if (on_stderr)
281		return;
282
283	switch (facility) {
284	case SYSLOG_FACILITY_DAEMON:
285		log_facility = LOG_DAEMON;
286		break;
287	case SYSLOG_FACILITY_USER:
288		log_facility = LOG_USER;
289		break;
290	case SYSLOG_FACILITY_AUTH:
291		log_facility = LOG_AUTH;
292		break;
293#ifdef LOG_AUTHPRIV
294	case SYSLOG_FACILITY_AUTHPRIV:
295		log_facility = LOG_AUTHPRIV;
296		break;
297#endif
298	case SYSLOG_FACILITY_LOCAL0:
299		log_facility = LOG_LOCAL0;
300		break;
301	case SYSLOG_FACILITY_LOCAL1:
302		log_facility = LOG_LOCAL1;
303		break;
304	case SYSLOG_FACILITY_LOCAL2:
305		log_facility = LOG_LOCAL2;
306		break;
307	case SYSLOG_FACILITY_LOCAL3:
308		log_facility = LOG_LOCAL3;
309		break;
310	case SYSLOG_FACILITY_LOCAL4:
311		log_facility = LOG_LOCAL4;
312		break;
313	case SYSLOG_FACILITY_LOCAL5:
314		log_facility = LOG_LOCAL5;
315		break;
316	case SYSLOG_FACILITY_LOCAL6:
317		log_facility = LOG_LOCAL6;
318		break;
319	case SYSLOG_FACILITY_LOCAL7:
320		log_facility = LOG_LOCAL7;
321		break;
322	default:
323		fprintf(stderr,
324		    "Unrecognized internal syslog facility code %d\n",
325		    (int) facility);
326		exit(1);
327	}
328
329	/*
330	 * If an external library (eg libwrap) attempts to use syslog
331	 * immediately after reexec, syslog may be pointing to the wrong
332	 * facility, so we force an open/close of syslog here.
333	 */
334#if defined(HAVE_OPENLOG_R) && defined(SYSLOG_DATA_INIT)
335	openlog_r(argv0 ? argv0 : __progname, LOG_PID, log_facility, &sdata);
336	closelog_r(&sdata);
337#else
338	openlog(argv0 ? argv0 : __progname, LOG_PID, log_facility);
339	closelog();
340#endif
341}
342
343void
344log_change_level(LogLevel new_log_level)
345{
346	/* no-op if log_init has not been called */
347	if (argv0 == NULL)
348		return;
349	log_init(argv0, new_log_level, log_facility, log_on_stderr);
350}
351
352int
353log_is_on_stderr(void)
354{
355	return log_on_stderr && log_stderr_fd == STDERR_FILENO;
356}
357
358/* redirect what would usually get written to stderr to specified file */
359void
360log_redirect_stderr_to(const char *logfile)
361{
362	int fd;
363
364	if ((fd = open(logfile, O_WRONLY|O_CREAT|O_APPEND, 0600)) == -1) {
365		fprintf(stderr, "Couldn't open logfile %s: %s\n", logfile,
366		     strerror(errno));
367		exit(1);
368	}
369	log_stderr_fd = fd;
370}
371
372#define MSGBUFSIZ 1024
373
374void
375set_log_handler(log_handler_fn *handler, void *ctx)
376{
377	log_handler = handler;
378	log_handler_ctx = ctx;
379}
380
381void
382do_log2(LogLevel level, const char *fmt,...)
383{
384	va_list args;
385
386	va_start(args, fmt);
387	do_log(level, fmt, args);
388	va_end(args);
389}
390
391void
392do_log(LogLevel level, const char *fmt, va_list args)
393{
394#if defined(HAVE_OPENLOG_R) && defined(SYSLOG_DATA_INIT)
395	struct syslog_data sdata = SYSLOG_DATA_INIT;
396#endif
397	char msgbuf[MSGBUFSIZ];
398	char fmtbuf[MSGBUFSIZ];
399	char *txt = NULL;
400	int pri = LOG_INFO;
401	int saved_errno = errno;
402	log_handler_fn *tmp_handler;
403
404	if (level > log_level)
405		return;
406
407	switch (level) {
408	case SYSLOG_LEVEL_FATAL:
409		if (!log_on_stderr)
410			txt = "fatal";
411		pri = LOG_CRIT;
412		break;
413	case SYSLOG_LEVEL_ERROR:
414		if (!log_on_stderr)
415			txt = "error";
416		pri = LOG_ERR;
417		break;
418	case SYSLOG_LEVEL_INFO:
419		pri = LOG_INFO;
420		break;
421	case SYSLOG_LEVEL_VERBOSE:
422		pri = LOG_INFO;
423		break;
424	case SYSLOG_LEVEL_DEBUG1:
425		txt = "debug1";
426		pri = LOG_DEBUG;
427		break;
428	case SYSLOG_LEVEL_DEBUG2:
429		txt = "debug2";
430		pri = LOG_DEBUG;
431		break;
432	case SYSLOG_LEVEL_DEBUG3:
433		txt = "debug3";
434		pri = LOG_DEBUG;
435		break;
436	default:
437		txt = "internal error";
438		pri = LOG_ERR;
439		break;
440	}
441	if (txt != NULL && log_handler == NULL) {
442		snprintf(fmtbuf, sizeof(fmtbuf), "%s: %s", txt, fmt);
443		vsnprintf(msgbuf, sizeof(msgbuf), fmtbuf, args);
444	} else {
445		vsnprintf(msgbuf, sizeof(msgbuf), fmt, args);
446	}
447	strnvis(fmtbuf, msgbuf, sizeof(fmtbuf),
448	    log_on_stderr ? LOG_STDERR_VIS : LOG_SYSLOG_VIS);
449	if (log_handler != NULL) {
450		/* Avoid recursion */
451		tmp_handler = log_handler;
452		log_handler = NULL;
453		tmp_handler(level, fmtbuf, log_handler_ctx);
454		log_handler = tmp_handler;
455	} else if (log_on_stderr) {
456		snprintf(msgbuf, sizeof msgbuf, "%s\r\n", fmtbuf);
457		(void)write(log_stderr_fd, msgbuf, strlen(msgbuf));
458	} else {
459#if defined(HAVE_OPENLOG_R) && defined(SYSLOG_DATA_INIT)
460		openlog_r(argv0 ? argv0 : __progname, LOG_PID, log_facility, &sdata);
461		syslog_r(pri, &sdata, "%.500s", fmtbuf);
462		closelog_r(&sdata);
463#else
464		openlog(argv0 ? argv0 : __progname, LOG_PID, log_facility);
465		syslog(pri, "%.500s", fmtbuf);
466		closelog();
467#endif
468	}
469	errno = saved_errno;
470}
471