aboutsummaryrefslogtreecommitdiffstats
path: root/src/logging.c
blob: b030f8a687e7e4f0ec8b7109eba2071748b03114 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
/*! \file logging.c
 * Debugging/Logging support code. */
/*
 * (C) 2008-2010 by Harald Welte <laforge@gnumonks.org>
 * (C) 2008 by Holger Hans Peter Freyther <zecke@selfish.org>
 * All Rights Reserved
 *
 * SPDX-License-Identifier: GPL-2.0+
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 */

/*! \addtogroup logging
 * @{
 * libosmocore Logging sub-system
 *
 * \file logging.c */

#include "../config.h"

#include <stdarg.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>

#ifdef HAVE_STRINGS_H
#include <strings.h>
#endif
#include <time.h>
#include <sys/time.h>
#include <errno.h>
#include <pthread.h>

#include <osmocom/core/talloc.h>
#include <osmocom/core/utils.h>
#include <osmocom/core/logging.h>
#include <osmocom/core/timer.h>

#include <osmocom/vty/logging.h>	/* for LOGGING_STR. */

osmo_static_assert(_LOG_CTX_COUNT <= ARRAY_SIZE(((struct log_context*)NULL)->ctx),
		   enum_logging_ctx_items_fit_in_struct_log_context);
osmo_static_assert(_LOG_FLT_COUNT <= ARRAY_SIZE(((struct log_target*)NULL)->filter_data),
		   enum_logging_filters_fit_in_log_target_filter_data);
osmo_static_assert(_LOG_FLT_COUNT <= 8*sizeof(((struct log_target*)NULL)->filter_map),
		   enum_logging_filters_fit_in_log_target_filter_map);

struct log_info *osmo_log_info;

static struct log_context log_context;
void *tall_log_ctx = NULL;
LLIST_HEAD(osmo_log_target_list);

#if (!EMBEDDED)
/*! This mutex must be held while using osmo_log_target_list or any of its
  log_targets in a multithread program. Prevents race conditions between threads
  like producing unordered timestamps or VTY deleting a target while another
  thread is writing to it */
static pthread_mutex_t osmo_log_tgt_mutex;
static bool osmo_log_tgt_mutex_on = false;

/*! Enable multithread support (mutex) in libosmocore logging system.
 * Must be called by processes willing to use logging subsystem from several
 * threads. Once enabled, it's not possible to disable it again.
 */
void log_enable_multithread(void) {
	if (osmo_log_tgt_mutex_on)
		return;
	pthread_mutex_init(&osmo_log_tgt_mutex, NULL);
	osmo_log_tgt_mutex_on = true;
}

/*! Acquire the osmo_log_tgt_mutex. Don't use this function directly, always use
 *  macro log_tgt_mutex_lock() instead.
 */
void log_tgt_mutex_lock_impl(void) {
	/* These lines are useful to debug scenarios where there's only 1 thread
	   and a double lock appears, for instance during startup and some
	   unlock() missing somewhere:
	if (osmo_log_tgt_mutex_on && pthread_mutex_trylock(&osmo_log_tgt_mutex) != 0)
		osmo_panic("acquiring already locked mutex!\n");
	return;
	*/

	if (osmo_log_tgt_mutex_on)
		pthread_mutex_lock(&osmo_log_tgt_mutex);
}

/*! Release the osmo_log_tgt_mutex. Don't use this function directly, always use
 *  macro log_tgt_mutex_unlock() instead.
 */
void log_tgt_mutex_unlock_impl(void) {
	if (osmo_log_tgt_mutex_on)
		pthread_mutex_unlock(&osmo_log_tgt_mutex);
}

#else /* if (!EMBEDDED) */
#pragma message ("logging multithread support disabled in embedded build")
void log_enable_multithread(void) {}
void log_tgt_mutex_lock_impl(void) {}
void log_tgt_mutex_unlock_impl(void) {}
#endif /* if (!EMBEDDED) */

const struct value_string loglevel_strs[] = {
	{ LOGL_DEBUG,	"DEBUG" },
	{ LOGL_INFO,	"INFO" },
	{ LOGL_NOTICE,	"NOTICE" },
	{ LOGL_ERROR,	"ERROR" },
	{ LOGL_FATAL,	"FATAL" },
	{ 0, NULL },
};

#define INT2IDX(x)	(-1*(x)-1)
static const struct log_info_cat internal_cat[OSMO_NUM_DLIB] = {
	[INT2IDX(DLGLOBAL)] = {	/* -1 becomes 0 */
		.name = "DLGLOBAL",
		.description = "Library-internal global log family",
		.loglevel = LOGL_NOTICE,
		.enabled = 1,
	},
	[INT2IDX(DLLAPD)] = {	/* -2 becomes 1 */
		.name = "DLLAPD",
		.description = "LAPD in libosmogsm",
		.loglevel = LOGL_NOTICE,
		.enabled = 1,
	},
	[INT2IDX(DLINP)] = {
		.name = "DLINP",
		.description = "A-bis Intput Subsystem",
		.loglevel = LOGL_NOTICE,
		.enabled = 1,
	},
	[INT2IDX(DLMUX)] = {
		.name = "DLMUX",
		.description = "A-bis B-Subchannel TRAU Frame Multiplex",
		.loglevel = LOGL_NOTICE,
		.enabled = 1,
	},
	[INT2IDX(DLMI)] = {
		.name = "DLMI",
		.description = "A-bis Input Driver for Signalling",
		.enabled = 0, .loglevel = LOGL_NOTICE,
	},
	[INT2IDX(DLMIB)] = {
		.name = "DLMIB",
		.description = "A-bis Input Driver for B-Channels (voice)",
		.enabled = 0, .loglevel = LOGL_NOTICE,
	},
	[INT2IDX(DLSMS)] = {
		.name = "DLSMS",
		.description = "Layer3 Short Message Service (SMS)",
		.enabled = 1, .loglevel = LOGL_NOTICE,
		.color = "\033[1;38m",
	},
	[INT2IDX(DLCTRL)] = {
		.name = "DLCTRL",
		.description = "Control Interface",
		.enabled = 1, .loglevel = LOGL_NOTICE,
	},
	[INT2IDX(DLGTP)] = {
		.name = "DLGTP",
		.description = "GPRS GTP library",
		.enabled = 1, .loglevel = LOGL_NOTICE,
	},
	[INT2IDX(DLSTATS)] = {
		.name = "DLSTATS",
		.description = "Statistics messages and logging",
		.enabled = 1, .loglevel = LOGL_NOTICE,
	},
	[INT2IDX(DLGSUP)] = {
		.name = "DLGSUP",
		.description = "Generic Subscriber Update Protocol",
		.enabled = 1, .loglevel = LOGL_NOTICE,
	},
	[INT2IDX(DLOAP)] = {
		.name = "DLOAP",
		.description = "Osmocom Authentication Protocol",
		.enabled = 1, .loglevel = LOGL_NOTICE,
	},
	[INT2IDX(DLSS7)] = {
		.name = "DLSS7",
		.description = "libosmo-sigtran Signalling System 7",
		.enabled = 1, .loglevel = LOGL_NOTICE,
	},
	[INT2IDX(DLSCCP)] = {
		.name = "DLSCCP",
		.description = "libosmo-sigtran SCCP Implementation",
		.enabled = 1, .loglevel = LOGL_NOTICE,
	},
	[INT2IDX(DLSUA)] = {
		.name = "DLSUA",
		.description = "libosmo-sigtran SCCP User Adaptation",
		.enabled = 1, .loglevel = LOGL_NOTICE,
	},
	[INT2IDX(DLM3UA)] = {
		.name = "DLM3UA",
		.description = "libosmo-sigtran MTP3 User Adaptation",
		.enabled = 1, .loglevel = LOGL_NOTICE,
	},
	[INT2IDX(DLMGCP)] = {
		.name = "DLMGCP",
		.description = "libosmo-mgcp Media Gateway Control Protocol",
		.enabled = 1, .loglevel = LOGL_NOTICE,
	},
	[INT2IDX(DLJIBUF)] = {
		.name = "DLJIBUF",
		.description = "libosmo-netif Jitter Buffer",
		.enabled = 1, .loglevel = LOGL_NOTICE,
	},
	[INT2IDX(DLRSPRO)] = {
		.name = "DLRSPRO",
		.description = "Remote SIM protocol",
		.enabled = 1, .loglevel = LOGL_NOTICE,
	},
};

void assert_loginfo(const char *src)
{
	if (!osmo_log_info) {
		fprintf(stderr, "ERROR: osmo_log_info == NULL! "
			"You must call log_init() before using logging in %s()!\n", src);
		OSMO_ASSERT(osmo_log_info);
	}
}

/* special magic for negative (library-internal) log subsystem numbers */
static int subsys_lib2index(int subsys)
{
	return (subsys * -1) + (osmo_log_info->num_cat_user-1);
}

/*! Parse a human-readable log level into a numeric value
 *  \param[in] lvl zero-terminated string containing log level name
 *  \returns numeric log level
 */
int log_parse_level(const char *lvl)
{
	return get_string_value(loglevel_strs, lvl);
}

/*! convert a numeric log level into human-readable string
 *  \param[in] lvl numeric log level
 *  \returns zero-terminated string (log level name)
 */
const char *log_level_str(unsigned int lvl)
{
	return get_value_string(loglevel_strs, lvl);
}

/*! parse a human-readable log category into numeric form
 *  \param[in] category human-readable log category name
 *  \returns numeric category value, or -EINVAL otherwise
 */
int log_parse_category(const char *category)
{
	int i;

	assert_loginfo(__func__);

	for (i = 0; i < osmo_log_info->num_cat; ++i) {
		if (osmo_log_info->cat[i].name == NULL)
			continue;
		if (!strcasecmp(osmo_log_info->cat[i].name+1, category))
			return i;
	}

	return -EINVAL;
}

/*! parse the log category mask
 *  \param[in] target log target to be configured
 *  \param[in] _mask log category mask string
 *
 * The format can be this: category1:category2:category3
 * or category1,2:category2,3:...
 */
void log_parse_category_mask(struct log_target* target, const char *_mask)
{
	int i = 0;
	char *mask = strdup(_mask);
	char *category_token = NULL;

	assert_loginfo(__func__);

	/* Disable everything to enable it afterwards */
	for (i = 0; i < osmo_log_info->num_cat; ++i)
		target->categories[i].enabled = 0;

	category_token = strtok(mask, ":");
	OSMO_ASSERT(category_token);
	do {
		for (i = 0; i < osmo_log_info->num_cat; ++i) {
			size_t length, cat_length;
			char* colon = strstr(category_token, ",");

			if (!osmo_log_info->cat[i].name)
				continue;

			length = strlen(category_token);
			cat_length = strlen(osmo_log_info->cat[i].name);

			/* Use longest length not to match subocurrences. */
			if (cat_length > length)
				length = cat_length;

			if (colon)
			    length = colon - category_token;

			if (strncasecmp(osmo_log_info->cat[i].name,
					category_token, length) == 0) {
				int level = 0;

				if (colon)
					level = atoi(colon+1);

				target->categories[i].enabled = 1;
				target->categories[i].loglevel = level;
			}
		}
	} while ((category_token = strtok(NULL, ":")));

	free(mask);
}

static const char* color(int subsys)
{
	if (subsys < osmo_log_info->num_cat)
		return osmo_log_info->cat[subsys].color;

	return NULL;
}

static const struct value_string level_colors[] = {
	{ LOGL_DEBUG, "\033[1;34m" },
	{ LOGL_INFO, "\033[1;32m" },
	{ LOGL_NOTICE, "\033[1;33m" },
	{ LOGL_ERROR, "\033[1;31m" },
	{ LOGL_FATAL, "\033[1;31m" },
	{ 0, NULL }
};

static const char *level_color(int level)
{
	const char *c = get_value_string_or_null(level_colors, level);
	if (!c)
		return get_value_string(level_colors, LOGL_FATAL);
	return c;
}

const char* log_category_name(int subsys)
{
	if (subsys < osmo_log_info->num_cat)
		return osmo_log_info->cat[subsys].name;

	return NULL;
}

static const char *const_basename(const char *path)
{
	const char *bn = strrchr(path, '/');
	if (!bn || !bn[1])
		return path;
	return bn + 1;
}

static void _output(struct log_target *target, unsigned int subsys,
		    unsigned int level, const char *file, int line, int cont,
		    const char *format, va_list ap)
{
	char buf[4096];
	int ret, len = 0, offset = 0, rem = sizeof(buf);
	const char *c_subsys = NULL;

	/* are we using color */
	if (target->use_color) {
		c_subsys = color(subsys);
		if (c_subsys) {
			ret = snprintf(buf + offset, rem, "%s", c_subsys);
			if (ret < 0)
				goto err;
			OSMO_SNPRINTF_RET(ret, rem, offset, len);
		}
	}
	if (!cont) {
		if (target->print_ext_timestamp) {
#ifdef HAVE_LOCALTIME_R
			struct tm tm;
			struct timeval tv;
			osmo_gettimeofday(&tv, NULL);
			localtime_r(&tv.tv_sec, &tm);
			ret = snprintf(buf + offset, rem, "%04d%02d%02d%02d%02d%02d%03d ",
					tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
					tm.tm_hour, tm.tm_min, tm.tm_sec,
					(int)(tv.tv_usec / 1000));
			if (ret < 0)
				goto err;
			OSMO_SNPRINTF_RET(ret, rem, offset, len);
#endif
		} else if (target->print_timestamp) {
			time_t tm;
			if ((tm = time(NULL)) == (time_t) -1)
				goto err;
			/* Get human-readable representation of time.
			   man ctime: we need at least 26 bytes in buf */
			if (rem < 26 || !ctime_r(&tm, buf + offset))
				goto err;
			ret = strlen(buf + offset);
			if (ret <= 0)
				goto err;
			/* Get rid of useless final '\n' added by ctime_r. We want a space instead. */
			buf[offset + ret - 1] = ' ';
			OSMO_SNPRINTF_RET(ret, rem, offset, len);
		}
		if (target->print_category) {
			ret = snprintf(buf + offset, rem, "%s%s%s%s ",
				       target->use_color ? level_color(level) : "",
				       log_category_name(subsys),
				       target->use_color ? "\033[0;m" : "",
				       c_subsys ? c_subsys : "");
			if (ret < 0)
				goto err;
			OSMO_SNPRINTF_RET(ret, rem, offset, len);
		}
		if (target->print_level) {
			ret = snprintf(buf + offset, rem, "%s%s%s%s ",
				       target->use_color ? level_color(level) : "",
				       log_level_str(level),
				       target->use_color ? "\033[0;m" : "",
				       c_subsys ? c_subsys : "");
			if (ret < 0)
				goto err;
			OSMO_SNPRINTF_RET(ret, rem, offset, len);
		}
		if (target->print_category_hex) {
			ret = snprintf(buf + offset, rem, "<%4.4x> ", subsys);
			if (ret < 0)
				goto err;
			OSMO_SNPRINTF_RET(ret, rem, offset, len);
		}

		if (target->print_filename_pos == LOG_FILENAME_POS_HEADER_END) {
			switch (target->print_filename2) {
			case LOG_FILENAME_NONE:
				break;
			case LOG_FILENAME_PATH:
				ret = snprintf(buf + offset, rem, "%s:%d ", file, line);
				if (ret < 0)
					goto err;
				OSMO_SNPRINTF_RET(ret, rem, offset, len);
				break;
			case LOG_FILENAME_BASENAME:
				ret = snprintf(buf + offset, rem, "%s:%d ", const_basename(file), line);
				if (ret < 0)
					goto err;
				OSMO_SNPRINTF_RET(ret, rem, offset, len);
				break;
			}
		}
	}
	ret = vsnprintf(buf + offset, rem, format, ap);
	if (ret < 0)
		goto err;
	OSMO_SNPRINTF_RET(ret, rem, offset, len);

	/* For LOG_FILENAME_POS_LAST, print the source file info only when the caller ended the log
	 * message in '\n'. If so, nip the last '\n' away, insert the source file info and re-append an
	 * '\n'. All this to allow LOGP("start..."); LOGPC("...end\n") constructs. */
	if (target->print_filename_pos == LOG_FILENAME_POS_LINE_END
	    && offset > 0 && buf[offset-1] == '\n') {
		switch (target->print_filename2) {
		case LOG_FILENAME_NONE:
			break;
		case LOG_FILENAME_PATH:
			offset --;
			ret = snprintf(buf + offset, rem, " (%s:%d)\n", file, line);
			if (ret < 0)
				goto err;
			OSMO_SNPRINTF_RET(ret, rem, offset, len);
			break;
		case LOG_FILENAME_BASENAME:
			offset --;
			ret = snprintf(buf + offset, rem, " (%s:%d)\n", const_basename(file), line);
			if (ret < 0)
				goto err;
			OSMO_SNPRINTF_RET(ret, rem, offset, len);
			break;
		}
	}

	if (target->use_color) {
		ret = snprintf(buf + offset, rem, "\033[0;m");
		if (ret < 0)
			goto err;
		OSMO_SNPRINTF_RET(ret, rem, offset, len);
	}
err:
	buf[sizeof(buf)-1] = '\0';
	target->output(target, level, buf);
}

/* Catch internal logging category indexes as well as out-of-bounds indexes.
 * For internal categories, the ID is negative starting with -1; and internal
 * logging categories are added behind the user categories. For out-of-bounds
 * indexes, return the index of DLGLOBAL. The returned category index is
 * guaranteed to exist in osmo_log_info, otherwise the program would abort,
 * which should never happen unless even the DLGLOBAL category is missing. */
static inline int map_subsys(int subsys)
{
	/* Note: comparing signed and unsigned integers */

	if (subsys > 0 && ((unsigned int)subsys) >= osmo_log_info->num_cat_user)
		subsys = DLGLOBAL;

	if (subsys < 0)
		subsys = subsys_lib2index(subsys);

	if (subsys < 0 || subsys >= osmo_log_info->num_cat)
		subsys = subsys_lib2index(DLGLOBAL);

	OSMO_ASSERT(!(subsys < 0 || subsys >= osmo_log_info->num_cat));

	return subsys;
}

static inline bool should_log_to_target(struct log_target *tar, int subsys,
					int level)
{
	struct log_category *category;

	category = &tar->categories[subsys];

	/* subsystem is not supposed to be logged */
	if (!category->enabled)
		return false;

	/* Check the global log level */
	if (tar->loglevel != 0 && level < tar->loglevel)
		return false;

	/* Check the category log level */
	if (tar->loglevel == 0 && category->loglevel != 0 &&
	    level < category->loglevel)
		return false;

	/* Apply filters here... if that becomes messy we will
	 * need to put filters in a list and each filter will
	 * say stop, continue, output */
	if ((tar->filter_map & (1 << LOG_FLT_ALL)) != 0)
		return true;

	if (osmo_log_info->filter_fn)
		return osmo_log_info->filter_fn(&log_context, tar);

	/* TODO: Check the filter/selector too? */
	return true;
}

/*! vararg version of logging function
 *  \param[in] subsys Logging sub-system
 *  \param[in] level Log level
 *  \param[in] file name of source code file
 *  \param[in] cont continuation (1) or new line (0)
 *  \param[in] format format string
 *  \param[in] ap vararg-list containing format string arguments
 */
void osmo_vlogp(int subsys, int level, const char *file, int line,
		int cont, const char *format, va_list ap)
{
	struct log_target *tar;

	subsys = map_subsys(subsys);

	log_tgt_mutex_lock();

	llist_for_each_entry(tar, &osmo_log_target_list, entry) {
		va_list bp;

		if (!should_log_to_target(tar, subsys, level))
			continue;

		/* According to the manpage, vsnprintf leaves the value of ap
		 * in undefined state. Since _output uses vsnprintf and it may
		 * be called several times, we have to pass a copy of ap. */
		va_copy(bp, ap);
		if (tar->raw_output)
			tar->raw_output(tar, subsys, level, file, line, cont, format, bp);
		else
			_output(tar, subsys, level, file, line, cont, format, bp);
		va_end(bp);
	}

	log_tgt_mutex_unlock();
}

/*! logging function used by DEBUGP() macro
 *  \param[in] subsys Logging sub-system
 *  \param[in] file name of source code file
 *  \param[in] cont continuation (1) or new line (0)
 *  \param[in] format format string
 */
void logp(int subsys, const char *file, int line, int cont,
	  const char *format, ...)
{
	va_list ap;

	va_start(ap, format);
	osmo_vlogp(subsys, LOGL_DEBUG, file, line, cont, format, ap);
	va_end(ap);
}

/*! logging function used by LOGP() macro
 *  \param[in] subsys Logging sub-system
 *  \param[in] level Log level
 *  \param[in] file name of source code file
 *  \param[in] cont continuation (1) or new line (0)
 *  \param[in] format format string
 */
void logp2(int subsys, unsigned int level, const char *file, int line, int cont, const char *format, ...)
{
	va_list ap;

	va_start(ap, format);
	osmo_vlogp(subsys, level, file, line, cont, format, ap);
	va_end(ap);
}

/*! Register a new log target with the logging core
 *  \param[in] target Log target to be registered
 */
void log_add_target(struct log_target *target)
{
	llist_add_tail(&target->entry, &osmo_log_target_list);
}

/*! Unregister a log target from the logging core
 *  \param[in] target Log target to be unregistered
 */
void log_del_target(struct log_target *target)
{
	llist_del(&target->entry);
}

/*! Reset (clear) the logging context */
void log_reset_context(void)
{
	memset(&log_context, 0, sizeof(log_context));
}

/*! Set the logging context
 *  \param[in] ctx_nr logging context number
 *  \param[in] value value to which the context is to be set
 *  \returns 0 in case of success; negative otherwise
 *
 * A logging context is something like the subscriber identity to which
 * the currently processed message relates, or the BTS through which it
 * was received.  As soon as this data is known, it can be set using
 * this function.  The main use of context information is for logging
 * filters.
 */
int log_set_context(uint8_t ctx_nr, void *value)
{
	if (ctx_nr > LOG_MAX_CTX)
		return -EINVAL;

	log_context.ctx[ctx_nr] = value;

	return 0;
}

/*! Enable the \ref LOG_FLT_ALL log filter
 *  \param[in] target Log target to be affected
 *  \param[in] all enable (1) or disable (0) the ALL filter
 *
 * When the \ref LOG_FLT_ALL filter is enabled, all log messages will be
 * printed.  It acts as a wildcard.  Setting it to \a 1 means there is no
 * filtering.
 */
void log_set_all_filter(struct log_target *target, int all)
{
	if (all)
		target->filter_map |= (1 << LOG_FLT_ALL);
	else
		target->filter_map &= ~(1 << LOG_FLT_ALL);
}

/*! Enable or disable the use of colored output
 *  \param[in] target Log target to be affected
 *  \param[in] use_color Use color (1) or don't use color (0)
 */
void log_set_use_color(struct log_target *target, int use_color)
{
	target->use_color = use_color;
}

/*! Enable or disable printing of timestamps while logging
 *  \param[in] target Log target to be affected
 *  \param[in] print_timestamp Enable (1) or disable (0) timestamps
 */
void log_set_print_timestamp(struct log_target *target, int print_timestamp)
{
	target->print_timestamp = print_timestamp;
}

/*! Enable or disable printing of extended timestamps while logging
 *  \param[in] target Log target to be affected
 *  \param[in] print_timestamp Enable (1) or disable (0) timestamps
 *
 * When both timestamp and extended timestamp is enabled then only
 * the extended timestamp will be used. The format of the timestamp
 * is YYYYMMDDhhmmssnnn.
 */
void log_set_print_extended_timestamp(struct log_target *target, int print_timestamp)
{
	target->print_ext_timestamp = print_timestamp;
}

/*! Use log_set_print_filename2() instead.
 * Call log_set_print_filename2() with LOG_FILENAME_PATH or LOG_FILENAME_NONE, *as well as* call
 * log_set_print_category_hex() with the argument passed to this function. This is to mirror legacy
 * behavior, which combined the category in hex with the filename. For example, if the category-hex
 * output were no longer affected by log_set_print_filename(), many unit tests (in libosmocore as well as
 * dependent projects) would fail since they expect the category to disappear along with the filename.
 *  \param[in] target Log target to be affected
 *  \param[in] print_filename Enable (1) or disable (0) filenames
 */
void log_set_print_filename(struct log_target *target, int print_filename)
{
	log_set_print_filename2(target, print_filename ? LOG_FILENAME_PATH : LOG_FILENAME_NONE);
	log_set_print_category_hex(target, print_filename);
}

/*! Enable or disable printing of the filename while logging.
 *  \param[in] target Log target to be affected.
 *  \param[in] lft An LOG_FILENAME_* enum value.
 * LOG_FILENAME_NONE omits the source file and line information from logs.
 * LOG_FILENAME_PATH prints the entire source file path as passed to LOGP macros.
 */
void log_set_print_filename2(struct log_target *target, enum log_filename_type lft)
{
	target->print_filename2 = lft;
}

/*! Set the position where on a log line the source file info should be logged.
 *  \param[in] target Log target to be affected.
 *  \param[in] pos A LOG_FILENAME_POS_* enum value.
 * LOG_FILENAME_POS_DEFAULT logs just before the caller supplied log message.
 * LOG_FILENAME_POS_LAST logs only at the end of a log line, where the caller issued an '\n' to end the
 */
void log_set_print_filename_pos(struct log_target *target, enum log_filename_pos pos)
{
	target->print_filename_pos = pos;
}

/*! Enable or disable printing of the category name
 *  \param[in] target Log target to be affected
 *  \param[in] print_category Enable (1) or disable (0) filenames
 *
 *  Print the category/subsys name in front of every log message.
 */
void log_set_print_category(struct log_target *target, int print_category)
{
	target->print_category = print_category;
}

/*! Enable or disable printing of the category number in hex ('<000b>').
 *  \param[in] target Log target to be affected.
 *  \param[in] print_category_hex Enable (1) or disable (0) hex category.
 */
void log_set_print_category_hex(struct log_target *target, int print_category_hex)
{
	target->print_category_hex = print_category_hex;
}

/*! Enable or disable printing of the log level name.
 *  \param[in] target Log target to be affected
 *  \param[in] print_level Enable (1) or disable (0) log level name
 *
 *  Print the log level name in front of every log message.
 */
void log_set_print_level(struct log_target *target, int print_level)
{
	target->print_level = (bool)print_level;
}

/*! Set the global log level for a given log target
 *  \param[in] target Log target to be affected
 *  \param[in] log_level New global log level
 */
void log_set_log_level(struct log_target *target, int log_level)
{
	target->loglevel = log_level;
}

/*! Set a category filter on a given log target
 *  \param[in] target Log target to be affected
 *  \param[in] category Log category to be affected
 *  \param[in] enable whether to enable or disable the filter
 *  \param[in] level Log level of the filter
 */
void log_set_category_filter(struct log_target *target, int category,
			       int enable, int level)
{
	if (!target)
		return;
	category = map_subsys(category);
	target->categories[category].enabled = !!enable;
	target->categories[category].loglevel = level;
}

#if (!EMBEDDED)
static void _file_output(struct log_target *target, unsigned int level,
			 const char *log)
{
	fprintf(target->tgt_file.out, "%s", log);
	fflush(target->tgt_file.out);
}
#endif

/*! Create a new log target skeleton
 *  \returns dynamically-allocated log target
 *  This funcition allocates a \ref log_target and initializes it
 *  with some default values.  The newly created target is not
 *  registered yet.
 */
struct log_target *log_target_create(void)
{
	struct log_target *target;
	unsigned int i;

	assert_loginfo(__func__);

	target = talloc_zero(tall_log_ctx, struct log_target);
	if (!target)
		return NULL;

	target->categories = talloc_zero_array(target,
						struct log_category,
						osmo_log_info->num_cat);
	if (!target->categories) {
		talloc_free(target);
		return NULL;
	}

	INIT_LLIST_HEAD(&target->entry);

	/* initialize the per-category enabled/loglevel from defaults */
	for (i = 0; i < osmo_log_info->num_cat; i++) {
		struct log_category *cat = &target->categories[i];
		cat->enabled = osmo_log_info->cat[i].enabled;
		cat->loglevel = osmo_log_info->cat[i].loglevel;
	}

	/* global settings */
	target->use_color = 1;
	target->print_timestamp = 0;
	target->print_filename2 = LOG_FILENAME_PATH;
	target->print_category_hex = true;

	/* global log level */
	target->loglevel = 0;
	return target;
}

/*! Create the STDERR log target
 *  \returns dynamically-allocated \ref log_target for STDERR */
struct log_target *log_target_create_stderr(void)
{
/* since C89/C99 says stderr is a macro, we can safely do this! */
#if !EMBEDDED && defined(stderr)
	struct log_target *target;

	target = log_target_create();
	if (!target)
		return NULL;

	target->type = LOG_TGT_TYPE_STDERR;
	target->tgt_file.out = stderr;
	target->output = _file_output;
	return target;
#else
	return NULL;
#endif /* stderr */
}

#if (!EMBEDDED)
/*! Create a new file-based log target
 *  \param[in] fname File name of the new log file
 *  \returns Log target in case of success, NULL otherwise
 */
struct log_target *log_target_create_file(const char *fname)
{
	struct log_target *target;

	target = log_target_create();
	if (!target)
		return NULL;

	target->type = LOG_TGT_TYPE_FILE;
	target->tgt_file.out = fopen(fname, "a");
	if (!target->tgt_file.out)
		return NULL;

	target->output = _file_output;

	target->tgt_file.fname = talloc_strdup(target, fname);

	return target;
}
#endif

/*! Find a registered log target
 *  \param[in] type Log target type
 *  \param[in] fname File name
 *  \returns Log target (if found), NULL otherwise
 *  Must be called with mutex osmo_log_tgt_mutex held, see log_tgt_mutex_lock.
 */
struct log_target *log_target_find(int type, const char *fname)
{
	struct log_target *tgt;

	llist_for_each_entry(tgt, &osmo_log_target_list, entry) {
		if (tgt->type != type)
			continue;
		switch (tgt->type) {
		case LOG_TGT_TYPE_FILE:
			if (!strcmp(fname, tgt->tgt_file.fname))
				return tgt;
			break;
		case LOG_TGT_TYPE_GSMTAP:
			if (!strcmp(fname, tgt->tgt_gsmtap.hostname))
				return tgt;
			break;
		default:
			return tgt;
		}
	}
	return NULL;
}

/*! Unregister, close and delete a log target
 *  \param[in] target log target to unregister, close and delete */
void log_target_destroy(struct log_target *target)
{

	/* just in case, to make sure we don't have any references */
	log_del_target(target);

#if (!EMBEDDED)
	if (target->output == &_file_output) {
/* since C89/C99 says stderr is a macro, we can safely do this! */
#ifdef stderr
		/* don't close stderr */
		if (target->tgt_file.out != stderr)
#endif
		{
			fclose(target->tgt_file.out);
			target->tgt_file.out = NULL;
		}
	}
#endif

	talloc_free(target);
}

/*! close and re-open a log file (for log file rotation)
 *  \param[in] target log target to re-open
 *  \returns 0 in case of success; negative otherwise */
int log_target_file_reopen(struct log_target *target)
{
	fclose(target->tgt_file.out);

	target->tgt_file.out = fopen(target->tgt_file.fname, "a");
	if (!target->tgt_file.out)
		return -errno;

	/* we assume target->output already to be set */

	return 0;
}

/*! close and re-open all log files (for log file rotation)
 *  \returns 0 in case of success; negative otherwise */
int log_targets_reopen(void)
{
	struct log_target *tar;
	int rc = 0;

	log_tgt_mutex_lock();

	llist_for_each_entry(tar, &osmo_log_target_list, entry) {
		switch (tar->type) {
		case LOG_TGT_TYPE_FILE:
			if (log_target_file_reopen(tar) < 0)
				rc = -1;
			break;
		default:
			break;
		}
	}

	log_tgt_mutex_unlock();

	return rc;
}

/*! Initialize the Osmocom logging core
 *  \param[in] inf Information regarding logging categories, could be NULL
 *  \param[in] ctx talloc context for logging allocations
 *  \returns 0 in case of success, negative in case of error
 *
 *  If inf is NULL then only library-internal categories are initialized.
 */
int log_init(const struct log_info *inf, void *ctx)
{
	int i;

	tall_log_ctx = talloc_named_const(ctx, 1, "logging");
	if (!tall_log_ctx)
		return -ENOMEM;

	osmo_log_info = talloc_zero(tall_log_ctx, struct log_info);
	if (!osmo_log_info)
		return -ENOMEM;

	osmo_log_info->num_cat = ARRAY_SIZE(internal_cat);

	if (inf) {
		osmo_log_info->filter_fn = inf->filter_fn;
		osmo_log_info->num_cat_user = inf->num_cat;
		osmo_log_info->num_cat += inf->num_cat;
	}

	osmo_log_info->cat = talloc_zero_array(osmo_log_info,
					struct log_info_cat,
					osmo_log_info->num_cat);
	if (!osmo_log_info->cat) {
		talloc_free(osmo_log_info);
		osmo_log_info = NULL;
		return -ENOMEM;
	}

	if (inf) { /* copy over the user part */
		for (i = 0; i < inf->num_cat; i++) {
			memcpy((struct log_info_cat *) &osmo_log_info->cat[i],
			       &inf->cat[i], sizeof(struct log_info_cat));
		}
	}

	/* copy over the library part */
	for (i = 0; i < ARRAY_SIZE(internal_cat); i++) {
		unsigned int cn = osmo_log_info->num_cat_user + i;
		memcpy((struct log_info_cat *) &osmo_log_info->cat[cn],
			&internal_cat[i], sizeof(struct log_info_cat));
	}

	return 0;
}

/* De-initialize the Osmocom logging core
 * This function destroys all targets and releases associated memory */
void log_fini(void)
{
	struct log_target *tar, *tar2;

	log_tgt_mutex_lock();

	llist_for_each_entry_safe(tar, tar2, &osmo_log_target_list, entry)
		log_target_destroy(tar);

	talloc_free(osmo_log_info);
	osmo_log_info = NULL;
	talloc_free(tall_log_ctx);
	tall_log_ctx = NULL;

	log_tgt_mutex_unlock();
}

/*! Check whether a log entry will be generated.
 *  \returns != 0 if a log entry might get generated by at least one target */
int log_check_level(int subsys, unsigned int level)
{
	struct log_target *tar;

	assert_loginfo(__func__);

	subsys = map_subsys(subsys);

	/* TODO: The following could/should be cached (update on config) */

	log_tgt_mutex_lock();

	llist_for_each_entry(tar, &osmo_log_target_list, entry) {
		if (!should_log_to_target(tar, subsys, level))
			continue;

		/* This might get logged (ignoring filters) */
		log_tgt_mutex_unlock();
		return 1;
	}

	/* We are sure, that this will not be logged. */
	log_tgt_mutex_unlock();
	return 0;
}

/*! @} */