summaryrefslogtreecommitdiffstats
path: root/src/logging.c
blob: 214ad2ab2dd6a29d200cfba7d5de5c96ff617df7 (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
/* 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
 *
 * 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
 * @{
 */

/* \file logging.c */

#include "../config.h"

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

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

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

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

struct log_info *osmo_log_info;

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

#define LOGLEVEL_DEFS	6	/* Number of loglevels.*/

static const struct value_string loglevel_strs[LOGLEVEL_DEFS+1] = {
	{ 0,		"EVERYTHING" },
	{ 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",
	},
};

/*! \brief descriptive string for each log level */
/* You have to keep this in sync with the structure loglevel_strs. */
const char *loglevel_descriptions[LOGLEVEL_DEFS+1] = {
	"Log simply everything",
	"Log debug messages and higher levels",
	"Log informational messages and higher levels",
	"Log noticable messages and higher levels",
	"Log error messages and higher levels",
	"Log only fatal messages",
	NULL,
};

/* 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);
}

/*! \brief Parse a human-readable log level into a numeric value */
int log_parse_level(const char *lvl)
{
	return get_string_value(loglevel_strs, lvl);
}

/*! \brief convert a numeric log level into human-readable string */
const char *log_level_str(unsigned int lvl)
{
	return get_value_string(loglevel_strs, lvl);
}

/*! \brief 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;

	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;
}

/*! \brief 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;

	/* 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, ":");
	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 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);

	/* are we using color */
	if (target->use_color) {
		const char *c = color(subsys);
		if (c) {
			ret = snprintf(buf + offset, rem, "%s", color(subsys));
			if (ret < 0)
				goto err;
			OSMO_SNPRINTF_RET(ret, rem, offset, len);
		}
	}
	if (!cont) {
		if (target->print_timestamp) {
			char *timestr;
			time_t tm;
			tm = time(NULL);
			timestr = ctime(&tm);
			timestr[strlen(timestr)-1] = '\0';
			ret = snprintf(buf + offset, rem, "%s ", timestr);
			if (ret < 0)
				goto err;
			OSMO_SNPRINTF_RET(ret, rem, offset, len);
		}
		if (target->print_filename) {
			ret = snprintf(buf + offset, rem, "<%4.4x> %s:%d ",
					subsys, file, line);
			if (ret < 0)
				goto err;
			OSMO_SNPRINTF_RET(ret, rem, offset, len);
		}
	}
	ret = vsnprintf(buf + offset, rem, format, ap);
	if (ret < 0)
		goto err;
	OSMO_SNPRINTF_RET(ret, rem, offset, len);

	ret = snprintf(buf + offset, rem, "%s",
			target->use_color ? "\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);
}

/*! \brief vararg version of logging function */
void osmo_vlogp(int subsys, int level, const char *file, int line,
		int cont, const char *format, va_list ap)
{
	struct log_target *tar;

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

	if (subsys > osmo_log_info->num_cat)
		subsys = DLGLOBAL;

	llist_for_each_entry(tar, &osmo_log_target_list, entry) {
		struct log_category *category;
		int output = 0;
		va_list bp;

		category = &tar->categories[subsys];
		/* subsystem is not supposed to be logged */
		if (!category->enabled)
			continue;

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

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

		/* 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 & LOG_FILTER_ALL) != 0)
			output = 1;
		else if (osmo_log_info->filter_fn)
			output = osmo_log_info->filter_fn(&log_context,
						       tar);
		if (!output)
			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);
		_output(tar, subsys, level, file, line, cont, format, bp);
		va_end(bp);
	}
}

/*! \brief logging function used by DEBUGP() macro */
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);
}

/*! \brief logging function used by LOGP() macro */
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);
}

/*! \brief 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);
}

/*! \brief 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);
}

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

/*! \brief Set the logging context
 *  \param[in] ctx_nr logging context number
 *  \param[in] value value to which the context is to be set
 *
 * 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;
}

/*! \brief Enable the \ref LOG_FILTER_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_FILTER_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 |= LOG_FILTER_ALL;
	else
		target->filter_map &= ~LOG_FILTER_ALL;
}

/*! \brief 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;
}

/*! \brief 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;
}

/*! \brief Enable or disable printing of the filename while logging
 *  \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)
{
	target->print_filename = print_filename;
}

/*! \brief 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;
}

/*! \brief 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 (category >= osmo_log_info->num_cat)
		return;
	target->categories[category].enabled = !!enable;
	target->categories[category].loglevel = level;
}

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);
}

/*! \brief Create a new log target skeleton */
struct log_target *log_target_create(void)
{
	struct log_target *target;
	unsigned int i;

	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_filename = 1;

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

/*! \brief Create the STDERR log target */
struct log_target *log_target_create_stderr(void)
{
/* since C89/C99 says stderr is a macro, we can safely do this! */
#ifdef 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 */
}

/*! \brief 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;
}

/*! \brief Find a registered log target
 *  \param[in] type Log target type
 *  \param[in] fname File name
 *  \returns Log target (if found), NULL otherwise
 */
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;
		if (tgt->type == LOG_TGT_TYPE_FILE) {
			if (!strcmp(fname, tgt->tgt_file.fname))
				return tgt;
		} else
			return tgt;
	}
	return NULL;
}

/*! \brief Unregister, close and delete a log target */
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 (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;
		}
	}

	talloc_free(target);
}

/*! \brief close and re-open a log file (for log file rotation) */
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;
}

/*! \brief close and re-open a log file (for log file rotation) */
int log_targets_reopen(void)
{
	struct log_target *tar;
	int rc = 0;

	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;
		}
	}

	return rc;
}

/*! \brief Generates the logging command string for VTY
 *  \param[in] unused_info Deprecated parameter, no longer used!
 */
const char *log_vty_command_string(const struct log_info *unused_info)
{
	struct log_info *info = osmo_log_info;
	int len = 0, offset = 0, ret, i, rem;
	int size = strlen("logging level () ()") + 1;
	char *str;

	for (i = 0; i < info->num_cat; i++) {
		if (info->cat[i].name == NULL)
			continue;
		size += strlen(info->cat[i].name) + 1;
	}

	for (i = 0; i < LOGLEVEL_DEFS; i++)
		size += strlen(loglevel_strs[i].str) + 1;

	rem = size;
	str = talloc_zero_size(tall_log_ctx, size);
	if (!str)
		return NULL;

	ret = snprintf(str + offset, rem, "logging level (all|");
	if (ret < 0)
		goto err;
	OSMO_SNPRINTF_RET(ret, rem, offset, len);

	for (i = 0; i < info->num_cat; i++) {
		if (info->cat[i].name) {
			int j, name_len = strlen(info->cat[i].name)+1;
			char name[name_len];

			for (j = 0; j < name_len; j++)
				name[j] = tolower(info->cat[i].name[j]);

			name[name_len-1] = '\0';
			ret = snprintf(str + offset, rem, "%s|", name+1);
			if (ret < 0)
				goto err;
			OSMO_SNPRINTF_RET(ret, rem, offset, len);
		}
	}
	offset--;	/* to remove the trailing | */
	rem++;

	ret = snprintf(str + offset, rem, ") (");
	if (ret < 0)
		goto err;
	OSMO_SNPRINTF_RET(ret, rem, offset, len);

	for (i = 0; i < LOGLEVEL_DEFS; i++) {
		int j, loglevel_str_len = strlen(loglevel_strs[i].str)+1;
		char loglevel_str[loglevel_str_len];

		for (j = 0; j < loglevel_str_len; j++)
			loglevel_str[j] = tolower(loglevel_strs[i].str[j]);

		loglevel_str[loglevel_str_len-1] = '\0';
		ret = snprintf(str + offset, rem, "%s|", loglevel_str);
		if (ret < 0)
			goto err;
		OSMO_SNPRINTF_RET(ret, rem, offset, len);
	}
	offset--;	/* to remove the trailing | */
	rem++;

	ret = snprintf(str + offset, rem, ")");
	if (ret < 0)
		goto err;
	OSMO_SNPRINTF_RET(ret, rem, offset, len);
err:
	str[size-1] = '\0';
	return str;
}

/*! \brief Generates the logging command description for VTY
 *  \param[in] unused_info Deprecated parameter, no longer used!
 */
const char *log_vty_command_description(const struct log_info *unused_info)
{
	struct log_info *info = osmo_log_info;
	char *str;
	int i, ret, len = 0, offset = 0, rem;
	unsigned int size =
		strlen(LOGGING_STR
		       "Set the log level for a specified category\n") + 1;

	for (i = 0; i < info->num_cat; i++) {
		if (info->cat[i].name == NULL)
			continue;
		size += strlen(info->cat[i].description) + 1;
	}

	for (i = 0; i < LOGLEVEL_DEFS; i++)
		size += strlen(loglevel_descriptions[i]) + 1;

	size += strlen("Global setting for all subsystems") + 1;
	rem = size;
	str = talloc_zero_size(tall_log_ctx, size);
	if (!str)
		return NULL;

	ret = snprintf(str + offset, rem, LOGGING_STR
			"Set the log level for a specified category\n");
	if (ret < 0)
		goto err;
	OSMO_SNPRINTF_RET(ret, rem, offset, len);

	ret = snprintf(str + offset, rem,
			"Global setting for all subsystems\n");
	if (ret < 0)
		goto err;
	OSMO_SNPRINTF_RET(ret, rem, offset, len);

	for (i = 0; i < info->num_cat; i++) {
		if (info->cat[i].name == NULL)
			continue;
		ret = snprintf(str + offset, rem, "%s\n",
				info->cat[i].description);
		if (ret < 0)
			goto err;
		OSMO_SNPRINTF_RET(ret, rem, offset, len);
	}
	for (i = 0; i < LOGLEVEL_DEFS; i++) {
		ret = snprintf(str + offset, rem, "%s\n",
				loglevel_descriptions[i]);
		if (ret < 0)
			goto err;
		OSMO_SNPRINTF_RET(ret, rem, offset, len);
	}
err:
	str[size-1] = '\0';
	return str;
}

/*! \brief Initialize the Osmocom logging core
 *  \param[in] inf Information regarding logging categories
 *  \param[in] ctx \ref talloc context for logging allocations
 *  \returns 0 in case of success, negative in case of error
 */
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_user = inf->num_cat;
	/* total number = number of user cat + library cat */
	osmo_log_info->num_cat = inf->num_cat + ARRAY_SIZE(internal_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;
	}

	/* 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;
}

/*! @} */