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1 /* $OpenBSD: log.c,v 1.49 2017/03/10 03:15:58 djm 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 
55 static LogLevel log_level = SYSLOG_LEVEL_INFO;
56 static int log_on_stderr = 1;
57 static int log_stderr_fd = STDERR_FILENO;
58 static int log_facility = LOG_AUTH;
59 static char *argv0;
60 static log_handler_fn *log_handler;
61 static void *log_handler_ctx;
62 
63 extern 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 
70 static 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 
91 static 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 
108 SyslogFacility
log_facility_number(char * name)109 log_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 
120 const char *
log_facility_name(SyslogFacility facility)121 log_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 
131 LogLevel
log_level_number(char * name)132 log_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 
143 const char *
log_level_name(LogLevel level)144 log_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 
156 void
error(const char * fmt,...)157 error(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 
166 void
sigdie(const char * fmt,...)167 sigdie(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 
179 void
logdie(const char * fmt,...)180 logdie(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 
192 void
logit(const char * fmt,...)193 logit(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 
204 void
verbose(const char * fmt,...)205 verbose(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 
216 void
debug(const char * fmt,...)217 debug(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 
226 void
debug2(const char * fmt,...)227 debug2(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 
236 void
debug3(const char * fmt,...)237 debug3(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 
250 void
log_init(char * av0,LogLevel level,SyslogFacility facility,int on_stderr)251 log_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 
343 void
log_change_level(LogLevel new_log_level)344 log_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 
352 int
log_is_on_stderr(void)353 log_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 */
359 void
log_redirect_stderr_to(const char * logfile)360 log_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 
374 void
set_log_handler(log_handler_fn * handler,void * ctx)375 set_log_handler(log_handler_fn *handler, void *ctx)
376 {
377 	log_handler = handler;
378 	log_handler_ctx = ctx;
379 }
380 
381 void
do_log2(LogLevel level,const char * fmt,...)382 do_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 
391 void
do_log(LogLevel level,const char * fmt,va_list args)392 do_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",
457 		    (int)sizeof msgbuf - 3, fmtbuf);
458 		(void)write(log_stderr_fd, msgbuf, strlen(msgbuf));
459 	} else {
460 #if defined(HAVE_OPENLOG_R) && defined(SYSLOG_DATA_INIT)
461 		openlog_r(argv0 ? argv0 : __progname, LOG_PID, log_facility, &sdata);
462 		syslog_r(pri, &sdata, "%.500s", fmtbuf);
463 		closelog_r(&sdata);
464 #else
465 		openlog(argv0 ? argv0 : __progname, LOG_PID, log_facility);
466 		syslog(pri, "%.500s", fmtbuf);
467 		closelog();
468 #endif
469 	}
470 	errno = saved_errno;
471 }
472