xref: /freebsd/contrib/ntp/libntp/lib/isc/log.c (revision f126890ac5386406dadf7c4cfa9566cbb56537c5)
1 /*
2  * Copyright (C) 2004-2007, 2009, 2011, 2012  Internet Systems Consortium, Inc. ("ISC")
3  * Copyright (C) 1999-2003  Internet Software Consortium.
4  *
5  * Permission to use, copy, modify, and/or distribute this software for any
6  * purpose with or without fee is hereby granted, provided that the above
7  * copyright notice and this permission notice appear in all copies.
8  *
9  * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
10  * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
11  * AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
12  * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
13  * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
14  * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
15  * PERFORMANCE OF THIS SOFTWARE.
16  */
17 
18 /* $Id$ */
19 
20 /*! \file
21  * \author  Principal Authors: DCL */
22 
23 #include <config.h>
24 
25 #include <errno.h>
26 #include <stdlib.h>
27 #include <limits.h>
28 #include <time.h>
29 
30 #include <sys/types.h>	/* dev_t FreeBSD 2.1 */
31 
32 #include <isc/dir.h>
33 #include <isc/file.h>
34 #include <isc/log.h>
35 #include <isc/magic.h>
36 #include <isc/mem.h>
37 #include <isc/msgs.h>
38 #include <isc/print.h>
39 #include <isc/stat.h>
40 #include <isc/stdio.h>
41 #include <isc/string.h>
42 #include <isc/time.h>
43 #include <isc/util.h>
44 #include "ntp_stdlib.h"		/* NTP change for strlcpy, strlcat */
45 
46 #define LCTX_MAGIC		ISC_MAGIC('L', 'c', 't', 'x')
47 #define VALID_CONTEXT(lctx)	ISC_MAGIC_VALID(lctx, LCTX_MAGIC)
48 
49 #define LCFG_MAGIC		ISC_MAGIC('L', 'c', 'f', 'g')
50 #define VALID_CONFIG(lcfg)	ISC_MAGIC_VALID(lcfg, LCFG_MAGIC)
51 
52 /*
53  * XXXDCL make dynamic?
54  */
55 #define LOG_BUFFER_SIZE	(8 * 1024)
56 
57 #ifndef PATH_MAX
58 #define PATH_MAX 1024	/* AIX and others don't define this. */
59 #endif
60 
61 /*!
62  * This is the structure that holds each named channel.  A simple linked
63  * list chains all of the channels together, so an individual channel is
64  * found by doing strcmp()s with the names down the list.  Their should
65  * be no performance penalty from this as it is expected that the number
66  * of named channels will be no more than a dozen or so, and name lookups
67  * from the head of the list are only done when isc_log_usechannel() is
68  * called, which should also be very infrequent.
69  */
70 typedef struct isc_logchannel isc_logchannel_t;
71 
72 struct isc_logchannel {
73 	char *				name;
74 	unsigned int			type;
75 	int 				level;
76 	unsigned int			flags;
77 	isc_logdestination_t 		destination;
78 	ISC_LINK(isc_logchannel_t)	link;
79 };
80 
81 /*!
82  * The logchannellist structure associates categories and modules with
83  * channels.  First the appropriate channellist is found based on the
84  * category, and then each structure in the linked list is checked for
85  * a matching module.  It is expected that the number of channels
86  * associated with any given category will be very short, no more than
87  * three or four in the more unusual cases.
88  */
89 typedef struct isc_logchannellist isc_logchannellist_t;
90 
91 struct isc_logchannellist {
92 	const isc_logmodule_t *		module;
93 	isc_logchannel_t *		channel;
94 	ISC_LINK(isc_logchannellist_t)	link;
95 };
96 
97 /*!
98  * This structure is used to remember messages for pruning via
99  * isc_log_[v]write1().
100  */
101 typedef struct isc_logmessage isc_logmessage_t;
102 
103 struct isc_logmessage {
104 	char *				text;
105 	isc_time_t			time;
106 	ISC_LINK(isc_logmessage_t)	link;
107 };
108 
109 /*!
110  * The isc_logconfig structure is used to store the configurable information
111  * about where messages are actually supposed to be sent -- the information
112  * that could changed based on some configuration file, as opposed to the
113  * the category/module specification of isc_log_[v]write[1] that is compiled
114  * into a program, or the debug_level which is dynamic state information.
115  */
116 struct isc_logconfig {
117 	unsigned int			magic;
118 	isc_log_t *			lctx;
119 	ISC_LIST(isc_logchannel_t)	channels;
120 	ISC_LIST(isc_logchannellist_t) *channellists;
121 	unsigned int			channellist_count;
122 	unsigned int			duplicate_interval;
123 	int				highest_level;
124 	char *				tag;
125 	isc_boolean_t			dynamic;
126 };
127 
128 /*!
129  * This isc_log structure provides the context for the isc_log functions.
130  * The log context locks itself in isc_log_doit, the internal backend to
131  * isc_log_write.  The locking is necessary both to provide exclusive access
132  * to the buffer into which the message is formatted and to guard against
133  * competing threads trying to write to the same syslog resource.  (On
134  * some systems, such as BSD/OS, stdio is thread safe but syslog is not.)
135  * Unfortunately, the lock cannot guard against a _different_ logging
136  * context in the same program competing for syslog's attention.  Thus
137  * There Can Be Only One, but this is not enforced.
138  * XXXDCL enforce it?
139  *
140  * Note that the category and module information is not locked.
141  * This is because in the usual case, only one isc_log_t is ever created
142  * in a program, and the category/module registration happens only once.
143  * XXXDCL it might be wise to add more locking overall.
144  */
145 struct isc_log {
146 	/* Not locked. */
147 	unsigned int			magic;
148 	isc_mem_t *			mctx;
149 	isc_logcategory_t *		categories;
150 	unsigned int			category_count;
151 	isc_logmodule_t *		modules;
152 	unsigned int			module_count;
153 	int				debug_level;
154 	isc_mutex_t			lock;
155 	/* Locked by isc_log lock. */
156 	isc_logconfig_t * 		logconfig;
157 	char 				buffer[LOG_BUFFER_SIZE];
158 	ISC_LIST(isc_logmessage_t)	messages;
159 };
160 
161 /*!
162  * Used when ISC_LOG_PRINTLEVEL is enabled for a channel.
163  */
164 static const char *log_level_strings[] = {
165 	"debug",
166 	"info",
167 	"notice",
168 	"warning",
169 	"error",
170 	"critical"
171 };
172 
173 /*!
174  * Used to convert ISC_LOG_* priorities into syslog priorities.
175  * XXXDCL This will need modification for NT.
176  */
177 static const int syslog_map[] = {
178 	LOG_DEBUG,
179 	LOG_INFO,
180 	LOG_NOTICE,
181 	LOG_WARNING,
182 	LOG_ERR,
183 	LOG_CRIT
184 };
185 
186 /*!
187  * When adding new categories, a corresponding ISC_LOGCATEGORY_foo
188  * definition needs to be added to <isc/log.h>.
189  *
190  * The default category is provided so that the internal default can
191  * be overridden.  Since the default is always looked up as the first
192  * channellist in the log context, it must come first in isc_categories[].
193  */
194 LIBISC_EXTERNAL_DATA isc_logcategory_t isc_categories[] = {
195 	{ "default", 0 },	/* "default" must come first. */
196 	{ "general", 0 },
197 	{ NULL, 0 }
198 };
199 
200 /*!
201  * See above comment for categories on LIBISC_EXTERNAL_DATA, and apply it to modules.
202  */
203 LIBISC_EXTERNAL_DATA isc_logmodule_t isc_modules[] = {
204 	{ "socket", 0 },
205 	{ "time", 0 },
206 	{ "interface", 0 },
207 	{ "timer", 0 },
208 	{ "file", 0 },
209 	{ NULL, 0 }
210 };
211 
212 /*!
213  * This essentially constant structure must be filled in at run time,
214  * because its channel member is pointed to a channel that is created
215  * dynamically with isc_log_createchannel.
216  */
217 static isc_logchannellist_t default_channel;
218 
219 /*!
220  * libisc logs to this context.
221  */
222 LIBISC_EXTERNAL_DATA isc_log_t *isc_lctx = NULL;
223 
224 /*!
225  * Forward declarations.
226  */
227 static isc_result_t
228 assignchannel(isc_logconfig_t *lcfg, unsigned int category_id,
229 	      const isc_logmodule_t *module, isc_logchannel_t *channel);
230 
231 static isc_result_t
232 sync_channellist(isc_logconfig_t *lcfg);
233 
234 static isc_result_t
235 greatest_version(isc_logchannel_t *channel, int *greatest);
236 
237 static isc_result_t
238 roll_log(isc_logchannel_t *channel);
239 
240 static void
241 isc_log_doit(isc_log_t *lctx, isc_logcategory_t *category,
242 	     isc_logmodule_t *module, int level, isc_boolean_t write_once,
243 	     isc_msgcat_t *msgcat, int msgset, int msg,
244 	     const char *format, va_list args)
245      ISC_FORMAT_PRINTF(9, 0);
246 
247 /*@{*/
248 /*!
249  * Convenience macros.
250  */
251 
252 #define FACILITY(channel)	 (channel->destination.facility)
253 #define FILE_NAME(channel)	 (channel->destination.file.name)
254 #define FILE_STREAM(channel)	 (channel->destination.file.stream)
255 #define FILE_VERSIONS(channel)	 (channel->destination.file.versions)
256 #define FILE_MAXSIZE(channel)	 (channel->destination.file.maximum_size)
257 #define FILE_MAXREACHED(channel) (channel->destination.file.maximum_reached)
258 
259 /*@}*/
260 /****
261  **** Public interfaces.
262  ****/
263 
264 /*
265  * Establish a new logging context, with default channels.
266  */
267 isc_result_t
268 isc_log_create(isc_mem_t *mctx, isc_log_t **lctxp, isc_logconfig_t **lcfgp) {
269 	isc_log_t *lctx;
270 	isc_logconfig_t *lcfg = NULL;
271 	isc_result_t result;
272 
273 	REQUIRE(mctx != NULL);
274 	REQUIRE(lctxp != NULL && *lctxp == NULL);
275 	REQUIRE(lcfgp == NULL || *lcfgp == NULL);
276 
277 	lctx = isc_mem_get(mctx, sizeof(*lctx));
278 	if (lctx != NULL) {
279 		lctx->mctx = mctx;
280 		lctx->categories = NULL;
281 		lctx->category_count = 0;
282 		lctx->modules = NULL;
283 		lctx->module_count = 0;
284 		lctx->debug_level = 0;
285 
286 		ISC_LIST_INIT(lctx->messages);
287 
288 		result = isc_mutex_init(&lctx->lock);
289 		if (result != ISC_R_SUCCESS) {
290 			isc_mem_put(mctx, lctx, sizeof(*lctx));
291 			return (result);
292 		}
293 
294 		/*
295 		 * Normally setting the magic number is the last step done
296 		 * in a creation function, but a valid log context is needed
297 		 * by isc_log_registercategories and isc_logconfig_create.
298 		 * If either fails, the lctx is destroyed and not returned
299 		 * to the caller.
300 		 */
301 		lctx->magic = LCTX_MAGIC;
302 
303 		isc_log_registercategories(lctx, isc_categories);
304 		isc_log_registermodules(lctx, isc_modules);
305 		result = isc_logconfig_create(lctx, &lcfg);
306 
307 	} else
308 		result = ISC_R_NOMEMORY;
309 
310 	if (result == ISC_R_SUCCESS)
311 		result = sync_channellist(lcfg);
312 
313 	if (result == ISC_R_SUCCESS) {
314 		lctx->logconfig = lcfg;
315 
316 		*lctxp = lctx;
317 		if (lcfgp != NULL)
318 			*lcfgp = lcfg;
319 
320 	} else {
321 		if (lcfg != NULL)
322 			isc_logconfig_destroy(&lcfg);
323 		if (lctx != NULL)
324 			isc_log_destroy(&lctx);
325 	}
326 
327 	return (result);
328 }
329 
330 isc_result_t
331 isc_logconfig_create(isc_log_t *lctx, isc_logconfig_t **lcfgp) {
332 	isc_logconfig_t *lcfg;
333 	isc_logdestination_t destination;
334 	isc_result_t result = ISC_R_SUCCESS;
335 	int level = ISC_LOG_INFO;
336 
337 	REQUIRE(lcfgp != NULL && *lcfgp == NULL);
338 	REQUIRE(VALID_CONTEXT(lctx));
339 
340 	lcfg = isc_mem_get(lctx->mctx, sizeof(*lcfg));
341 
342 	if (lcfg != NULL) {
343 		lcfg->lctx = lctx;
344 		lcfg->channellists = NULL;
345 		lcfg->channellist_count = 0;
346 		lcfg->duplicate_interval = 0;
347 		lcfg->highest_level = level;
348 		lcfg->tag = NULL;
349 		lcfg->dynamic = ISC_FALSE;
350 
351 		ISC_LIST_INIT(lcfg->channels);
352 
353 		/*
354 		 * Normally the magic number is the last thing set in the
355 		 * structure, but isc_log_createchannel() needs a valid
356 		 * config.  If the channel creation fails, the lcfg is not
357 		 * returned to the caller.
358 		 */
359 		lcfg->magic = LCFG_MAGIC;
360 
361 	} else
362 		result = ISC_R_NOMEMORY;
363 
364 	/*
365 	 * Create the default channels:
366 	 *   	default_syslog, default_stderr, default_debug and null.
367 	 */
368 	if (result == ISC_R_SUCCESS) {
369 		destination.facility = LOG_DAEMON;
370 		result = isc_log_createchannel(lcfg, "default_syslog",
371 					       ISC_LOG_TOSYSLOG, level,
372 					       &destination, 0);
373 	}
374 
375 	if (result == ISC_R_SUCCESS) {
376 		destination.file.stream = stderr;
377 		destination.file.name = NULL;
378 		destination.file.versions = ISC_LOG_ROLLNEVER;
379 		destination.file.maximum_size = 0;
380 		result = isc_log_createchannel(lcfg, "default_stderr",
381 					       ISC_LOG_TOFILEDESC,
382 					       level,
383 					       &destination,
384 					       ISC_LOG_PRINTTIME);
385 	}
386 
387 	if (result == ISC_R_SUCCESS) {
388 		/*
389 		 * Set the default category's channel to default_stderr,
390 		 * which is at the head of the channels list because it was
391 		 * just created.
392 		 */
393 		default_channel.channel = ISC_LIST_HEAD(lcfg->channels);
394 
395 		destination.file.stream = stderr;
396 		destination.file.name = NULL;
397 		destination.file.versions = ISC_LOG_ROLLNEVER;
398 		destination.file.maximum_size = 0;
399 		result = isc_log_createchannel(lcfg, "default_debug",
400 					       ISC_LOG_TOFILEDESC,
401 					       ISC_LOG_DYNAMIC,
402 					       &destination,
403 					       ISC_LOG_PRINTTIME);
404 	}
405 
406 	if (result == ISC_R_SUCCESS)
407 		result = isc_log_createchannel(lcfg, "null",
408 					       ISC_LOG_TONULL,
409 					       ISC_LOG_DYNAMIC,
410 					       NULL, 0);
411 
412 	if (result == ISC_R_SUCCESS)
413 		*lcfgp = lcfg;
414 
415 	else
416 		if (lcfg != NULL)
417 			isc_logconfig_destroy(&lcfg);
418 
419 	return (result);
420 }
421 
422 isc_logconfig_t *
423 isc_logconfig_get(isc_log_t *lctx) {
424 	REQUIRE(VALID_CONTEXT(lctx));
425 
426 	ENSURE(lctx->logconfig != NULL);
427 
428 	return (lctx->logconfig);
429 }
430 
431 isc_result_t
432 isc_logconfig_use(isc_log_t *lctx, isc_logconfig_t *lcfg) {
433 	isc_logconfig_t *old_cfg;
434 	isc_result_t result;
435 
436 	REQUIRE(VALID_CONTEXT(lctx));
437 	REQUIRE(VALID_CONFIG(lcfg));
438 	REQUIRE(lcfg->lctx == lctx);
439 
440 	/*
441 	 * Ensure that lcfg->channellist_count == lctx->category_count.
442 	 * They won't be equal if isc_log_usechannel has not been called
443 	 * since any call to isc_log_registercategories.
444 	 */
445 	result = sync_channellist(lcfg);
446 	if (result != ISC_R_SUCCESS)
447 		return (result);
448 
449 	LOCK(&lctx->lock);
450 
451 	old_cfg = lctx->logconfig;
452 	lctx->logconfig = lcfg;
453 
454 	UNLOCK(&lctx->lock);
455 
456 	isc_logconfig_destroy(&old_cfg);
457 
458 	return (ISC_R_SUCCESS);
459 }
460 
461 void
462 isc_log_destroy(isc_log_t **lctxp) {
463 	isc_log_t *lctx;
464 	isc_logconfig_t *lcfg;
465 	isc_mem_t *mctx;
466 	isc_logmessage_t *message;
467 
468 	REQUIRE(lctxp != NULL && VALID_CONTEXT(*lctxp));
469 
470 	lctx = *lctxp;
471 	mctx = lctx->mctx;
472 
473 	if (lctx->logconfig != NULL) {
474 		lcfg = lctx->logconfig;
475 		lctx->logconfig = NULL;
476 		isc_logconfig_destroy(&lcfg);
477 	}
478 
479 	DESTROYLOCK(&lctx->lock);
480 
481 	while ((message = ISC_LIST_HEAD(lctx->messages)) != NULL) {
482 		ISC_LIST_UNLINK(lctx->messages, message, link);
483 
484 		isc_mem_put(mctx, message,
485 			    sizeof(*message) + strlen(message->text) + 1);
486 	}
487 
488 	lctx->buffer[0] = '\0';
489 	lctx->debug_level = 0;
490 	lctx->categories = NULL;
491 	lctx->category_count = 0;
492 	lctx->modules = NULL;
493 	lctx->module_count = 0;
494 	lctx->mctx = NULL;
495 	lctx->magic = 0;
496 
497 	isc_mem_put(mctx, lctx, sizeof(*lctx));
498 
499 	*lctxp = NULL;
500 }
501 
502 void
503 isc_logconfig_destroy(isc_logconfig_t **lcfgp) {
504 	isc_logconfig_t *lcfg;
505 	isc_mem_t *mctx;
506 	isc_logchannel_t *channel;
507 	isc_logchannellist_t *item;
508 	char *filename;
509 	unsigned int i;
510 
511 	REQUIRE(lcfgp != NULL && VALID_CONFIG(*lcfgp));
512 
513 	lcfg = *lcfgp;
514 
515 	/*
516 	 * This function cannot be called with a logconfig that is in
517 	 * use by a log context.
518 	 */
519 	REQUIRE(lcfg->lctx != NULL && lcfg->lctx->logconfig != lcfg);
520 
521 	mctx = lcfg->lctx->mctx;
522 
523 	while ((channel = ISC_LIST_HEAD(lcfg->channels)) != NULL) {
524 		ISC_LIST_UNLINK(lcfg->channels, channel, link);
525 
526 		if (channel->type == ISC_LOG_TOFILE) {
527 			/*
528 			 * The filename for the channel may have ultimately
529 			 * started its life in user-land as a const string,
530 			 * but in isc_log_createchannel it gets copied
531 			 * into writable memory and is not longer truly const.
532 			 */
533 			DE_CONST(FILE_NAME(channel), filename);
534 			isc_mem_free(mctx, filename);
535 
536 			if (FILE_STREAM(channel) != NULL)
537 				(void)fclose(FILE_STREAM(channel));
538 		}
539 
540 		isc_mem_free(mctx, channel->name);
541 		isc_mem_put(mctx, channel, sizeof(*channel));
542 	}
543 
544 	for (i = 0; i < lcfg->channellist_count; i++)
545 		while ((item = ISC_LIST_HEAD(lcfg->channellists[i])) != NULL) {
546 			ISC_LIST_UNLINK(lcfg->channellists[i], item, link);
547 			isc_mem_put(mctx, item, sizeof(*item));
548 		}
549 
550 	if (lcfg->channellist_count > 0)
551 		isc_mem_put(mctx, lcfg->channellists,
552 			    lcfg->channellist_count *
553 			    sizeof(ISC_LIST(isc_logchannellist_t)));
554 
555 	lcfg->dynamic = ISC_FALSE;
556 	if (lcfg->tag != NULL)
557 		isc_mem_free(lcfg->lctx->mctx, lcfg->tag);
558 	lcfg->tag = NULL;
559 	lcfg->highest_level = 0;
560 	lcfg->duplicate_interval = 0;
561 	lcfg->magic = 0;
562 
563 	isc_mem_put(mctx, lcfg, sizeof(*lcfg));
564 
565 	*lcfgp = NULL;
566 }
567 
568 void
569 isc_log_registercategories(isc_log_t *lctx, isc_logcategory_t categories[]) {
570 	isc_logcategory_t *catp;
571 
572 	REQUIRE(VALID_CONTEXT(lctx));
573 	REQUIRE(categories != NULL && categories[0].name != NULL);
574 
575 	/*
576 	 * XXXDCL This somewhat sleazy situation of using the last pointer
577 	 * in one category array to point to the next array exists because
578 	 * this registration function returns void and I didn't want to have
579 	 * change everything that used it by making it return an isc_result_t.
580 	 * It would need to do that if it had to allocate memory to store
581 	 * pointers to each array passed in.
582 	 */
583 	if (lctx->categories == NULL)
584 		lctx->categories = categories;
585 
586 	else {
587 		/*
588 		 * Adjust the last (NULL) pointer of the already registered
589 		 * categories to point to the incoming array.
590 		 */
591 		for (catp = lctx->categories; catp->name != NULL; )
592 			if (catp->id == UINT_MAX)
593 				/*
594 				 * The name pointer points to the next array.
595 				 * Ick.
596 				 */
597 				DE_CONST(catp->name, catp);
598 			else
599 				catp++;
600 
601 		catp->name = (void *)categories;
602 		catp->id = UINT_MAX;
603 	}
604 
605 	/*
606 	 * Update the id number of the category with its new global id.
607 	 */
608 	for (catp = categories; catp->name != NULL; catp++)
609 		catp->id = lctx->category_count++;
610 }
611 
612 isc_logcategory_t *
613 isc_log_categorybyname(isc_log_t *lctx, const char *name) {
614 	isc_logcategory_t *catp;
615 
616 	REQUIRE(VALID_CONTEXT(lctx));
617 	REQUIRE(name != NULL);
618 
619 	for (catp = lctx->categories; catp->name != NULL; )
620 		if (catp->id == UINT_MAX)
621 			/*
622 			 * catp is neither modified nor returned to the
623 			 * caller, so removing its const qualifier is ok.
624 			 */
625 			DE_CONST(catp->name, catp);
626 		else {
627 			if (strcmp(catp->name, name) == 0)
628 				return (catp);
629 			catp++;
630 		}
631 
632 	return (NULL);
633 }
634 
635 void
636 isc_log_registermodules(isc_log_t *lctx, isc_logmodule_t modules[]) {
637 	isc_logmodule_t *modp;
638 
639 	REQUIRE(VALID_CONTEXT(lctx));
640 	REQUIRE(modules != NULL && modules[0].name != NULL);
641 
642 	/*
643 	 * XXXDCL This somewhat sleazy situation of using the last pointer
644 	 * in one category array to point to the next array exists because
645 	 * this registration function returns void and I didn't want to have
646 	 * change everything that used it by making it return an isc_result_t.
647 	 * It would need to do that if it had to allocate memory to store
648 	 * pointers to each array passed in.
649 	 */
650 	if (lctx->modules == NULL)
651 		lctx->modules = modules;
652 
653 	else {
654 		/*
655 		 * Adjust the last (NULL) pointer of the already registered
656 		 * modules to point to the incoming array.
657 		 */
658 		for (modp = lctx->modules; modp->name != NULL; )
659 			if (modp->id == UINT_MAX)
660 				/*
661 				 * The name pointer points to the next array.
662 				 * Ick.
663 				 */
664 				DE_CONST(modp->name, modp);
665 			else
666 				modp++;
667 
668 		modp->name = (void *)modules;
669 		modp->id = UINT_MAX;
670 	}
671 
672 	/*
673 	 * Update the id number of the module with its new global id.
674 	 */
675 	for (modp = modules; modp->name != NULL; modp++)
676 		modp->id = lctx->module_count++;
677 }
678 
679 isc_logmodule_t *
680 isc_log_modulebyname(isc_log_t *lctx, const char *name) {
681 	isc_logmodule_t *modp;
682 
683 	REQUIRE(VALID_CONTEXT(lctx));
684 	REQUIRE(name != NULL);
685 
686 	for (modp = lctx->modules; modp->name != NULL; )
687 		if (modp->id == UINT_MAX)
688 			/*
689 			 * modp is neither modified nor returned to the
690 			 * caller, so removing its const qualifier is ok.
691 			 */
692 			DE_CONST(modp->name, modp);
693 		else {
694 			if (strcmp(modp->name, name) == 0)
695 				return (modp);
696 			modp++;
697 		}
698 
699 	return (NULL);
700 }
701 
702 isc_result_t
703 isc_log_createchannel(isc_logconfig_t *lcfg, const char *name,
704 		      unsigned int type, int level,
705 		      const isc_logdestination_t *destination,
706 		      unsigned int flags)
707 {
708 	isc_logchannel_t *channel;
709 	isc_mem_t *mctx;
710 
711 	REQUIRE(VALID_CONFIG(lcfg));
712 	REQUIRE(name != NULL);
713 	REQUIRE(type == ISC_LOG_TOSYSLOG   || type == ISC_LOG_TOFILE ||
714 		type == ISC_LOG_TOFILEDESC || type == ISC_LOG_TONULL);
715 	REQUIRE(destination != NULL || type == ISC_LOG_TONULL);
716 	REQUIRE(level >= ISC_LOG_CRITICAL);
717 	REQUIRE((flags &
718 		 (unsigned int)~(ISC_LOG_PRINTALL | ISC_LOG_DEBUGONLY)) == 0);
719 
720 	/* XXXDCL find duplicate names? */
721 
722 	mctx = lcfg->lctx->mctx;
723 
724 	channel = isc_mem_get(mctx, sizeof(*channel));
725 	if (channel == NULL)
726 		return (ISC_R_NOMEMORY);
727 
728 	channel->name = isc_mem_strdup(mctx, name);
729 	if (channel->name == NULL) {
730 		isc_mem_put(mctx, channel, sizeof(*channel));
731 		return (ISC_R_NOMEMORY);
732 	}
733 
734 	channel->type = type;
735 	channel->level = level;
736 	channel->flags = flags;
737 	ISC_LINK_INIT(channel, link);
738 
739 	switch (type) {
740 	case ISC_LOG_TOSYSLOG:
741 		FACILITY(channel) = destination->facility;
742 		break;
743 
744 	case ISC_LOG_TOFILE:
745 		/*
746 		 * The file name is copied because greatest_version wants
747 		 * to scribble on it, so it needs to be definitely in
748 		 * writable memory.
749 		 */
750 		FILE_NAME(channel) =
751 			isc_mem_strdup(mctx, destination->file.name);
752 		FILE_STREAM(channel) = NULL;
753 		FILE_VERSIONS(channel) = destination->file.versions;
754 		FILE_MAXSIZE(channel) = destination->file.maximum_size;
755 		FILE_MAXREACHED(channel) = ISC_FALSE;
756 		break;
757 
758 	case ISC_LOG_TOFILEDESC:
759 		FILE_NAME(channel) = NULL;
760 		FILE_STREAM(channel) = destination->file.stream;
761 		FILE_MAXSIZE(channel) = 0;
762 		FILE_VERSIONS(channel) = ISC_LOG_ROLLNEVER;
763 		break;
764 
765 	case ISC_LOG_TONULL:
766 		/* Nothing. */
767 		break;
768 
769 	default:
770 		isc_mem_put(mctx, channel->name, strlen(channel->name) + 1);
771 		isc_mem_put(mctx, channel, sizeof(*channel));
772 		return (ISC_R_UNEXPECTED);
773 	}
774 
775 	ISC_LIST_PREPEND(lcfg->channels, channel, link);
776 
777 	/*
778 	 * If default_stderr was redefined, make the default category
779 	 * point to the new default_stderr.
780 	 */
781 	if (strcmp(name, "default_stderr") == 0)
782 		default_channel.channel = channel;
783 
784 	return (ISC_R_SUCCESS);
785 }
786 
787 isc_result_t
788 isc_log_usechannel(isc_logconfig_t *lcfg, const char *name,
789 		   const isc_logcategory_t *category,
790 		   const isc_logmodule_t *module)
791 {
792 	isc_log_t *lctx;
793 	isc_logchannel_t *channel;
794 	isc_result_t result = ISC_R_SUCCESS;
795 	unsigned int i;
796 
797 	REQUIRE(VALID_CONFIG(lcfg));
798 	REQUIRE(name != NULL);
799 
800 	lctx = lcfg->lctx;
801 
802 	REQUIRE(category == NULL || category->id < lctx->category_count);
803 	REQUIRE(module == NULL || module->id < lctx->module_count);
804 
805 	for (channel = ISC_LIST_HEAD(lcfg->channels); channel != NULL;
806 	     channel = ISC_LIST_NEXT(channel, link))
807 		if (strcmp(name, channel->name) == 0)
808 			break;
809 
810 	if (channel == NULL)
811 		return (ISC_R_NOTFOUND);
812 
813 	if (category != NULL)
814 		result = assignchannel(lcfg, category->id, module, channel);
815 
816 	else
817 		/*
818 		 * Assign to all categories.  Note that this includes
819 		 * the default channel.
820 		 */
821 		for (i = 0; i < lctx->category_count; i++) {
822 			result = assignchannel(lcfg, i, module, channel);
823 			if (result != ISC_R_SUCCESS)
824 				break;
825 		}
826 
827 	return (result);
828 }
829 
830 void
831 isc_log_write(isc_log_t *lctx, isc_logcategory_t *category,
832 	      isc_logmodule_t *module, int level, const char *format, ...)
833 {
834 	va_list args;
835 
836 	/*
837 	 * Contract checking is done in isc_log_doit().
838 	 */
839 
840 	va_start(args, format);
841 	isc_log_doit(lctx, category, module, level, ISC_FALSE,
842 		     NULL, 0, 0, format, args);
843 	va_end(args);
844 }
845 
846 void
847 isc_log_vwrite(isc_log_t *lctx, isc_logcategory_t *category,
848 	       isc_logmodule_t *module, int level,
849 	       const char *format, va_list args)
850 {
851 	/*
852 	 * Contract checking is done in isc_log_doit().
853 	 */
854 	isc_log_doit(lctx, category, module, level, ISC_FALSE,
855 		     NULL, 0, 0, format, args);
856 }
857 
858 void
859 isc_log_write1(isc_log_t *lctx, isc_logcategory_t *category,
860 	       isc_logmodule_t *module, int level, const char *format, ...)
861 {
862 	va_list args;
863 
864 	/*
865 	 * Contract checking is done in isc_log_doit().
866 	 */
867 
868 	va_start(args, format);
869 	isc_log_doit(lctx, category, module, level, ISC_TRUE,
870 		     NULL, 0, 0, format, args);
871 	va_end(args);
872 }
873 
874 void
875 isc_log_vwrite1(isc_log_t *lctx, isc_logcategory_t *category,
876 		isc_logmodule_t *module, int level,
877 		const char *format, va_list args)
878 {
879 	/*
880 	 * Contract checking is done in isc_log_doit().
881 	 */
882 	isc_log_doit(lctx, category, module, level, ISC_TRUE,
883 		     NULL, 0, 0, format, args);
884 }
885 
886 void
887 isc_log_iwrite(isc_log_t *lctx, isc_logcategory_t *category,
888 	       isc_logmodule_t *module, int level,
889 	       isc_msgcat_t *msgcat, int msgset, int msg,
890 	       const char *format, ...)
891 {
892 	va_list args;
893 
894 	/*
895 	 * Contract checking is done in isc_log_doit().
896 	 */
897 
898 	va_start(args, format);
899 	isc_log_doit(lctx, category, module, level, ISC_FALSE,
900 		     msgcat, msgset, msg, format, args);
901 	va_end(args);
902 }
903 
904 void
905 isc_log_ivwrite(isc_log_t *lctx, isc_logcategory_t *category,
906 	       isc_logmodule_t *module, int level,
907 	       isc_msgcat_t *msgcat, int msgset, int msg,
908 	       const char *format, va_list args)
909 {
910 	/*
911 	 * Contract checking is done in isc_log_doit().
912 	 */
913 	isc_log_doit(lctx, category, module, level, ISC_FALSE,
914 		     msgcat, msgset, msg, format, args);
915 }
916 
917 void
918 isc_log_iwrite1(isc_log_t *lctx, isc_logcategory_t *category,
919 		isc_logmodule_t *module, int level,
920 		isc_msgcat_t *msgcat, int msgset, int msg,
921 		const char *format, ...)
922 {
923 	va_list args;
924 
925 	/*
926 	 * Contract checking is done in isc_log_doit().
927 	 */
928 
929 	va_start(args, format);
930 	isc_log_doit(lctx, category, module, level, ISC_TRUE,
931 		     msgcat, msgset, msg, format, args);
932 	va_end(args);
933 }
934 
935 void
936 isc_log_ivwrite1(isc_log_t *lctx, isc_logcategory_t *category,
937 		 isc_logmodule_t *module, int level,
938 		 isc_msgcat_t *msgcat, int msgset, int msg,
939 		 const char *format, va_list args)
940 {
941 	/*
942 	 * Contract checking is done in isc_log_doit().
943 	 */
944 	isc_log_doit(lctx, category, module, level, ISC_TRUE,
945 		     msgcat, msgset, msg, format, args);
946 }
947 
948 void
949 isc_log_setcontext(isc_log_t *lctx) {
950 	isc_lctx = lctx;
951 }
952 
953 void
954 isc_log_setdebuglevel(isc_log_t *lctx, unsigned int level) {
955 	isc_logchannel_t *channel;
956 
957 	REQUIRE(VALID_CONTEXT(lctx));
958 
959 	LOCK(&lctx->lock);
960 
961 	lctx->debug_level = level;
962 	/*
963 	 * Close ISC_LOG_DEBUGONLY channels if level is zero.
964 	 */
965 	if (lctx->debug_level == 0)
966 		for (channel = ISC_LIST_HEAD(lctx->logconfig->channels);
967 		     channel != NULL;
968 		     channel = ISC_LIST_NEXT(channel, link))
969 			if (channel->type == ISC_LOG_TOFILE &&
970 			    (channel->flags & ISC_LOG_DEBUGONLY) != 0 &&
971 			    FILE_STREAM(channel) != NULL) {
972 				(void)fclose(FILE_STREAM(channel));
973 				FILE_STREAM(channel) = NULL;
974 			}
975 	UNLOCK(&lctx->lock);
976 }
977 
978 unsigned int
979 isc_log_getdebuglevel(isc_log_t *lctx) {
980 	REQUIRE(VALID_CONTEXT(lctx));
981 
982 	return (lctx->debug_level);
983 }
984 
985 void
986 isc_log_setduplicateinterval(isc_logconfig_t *lcfg, unsigned int interval) {
987 	REQUIRE(VALID_CONFIG(lcfg));
988 
989 	lcfg->duplicate_interval = interval;
990 }
991 
992 unsigned int
993 isc_log_getduplicateinterval(isc_logconfig_t *lcfg) {
994 	REQUIRE(VALID_CONTEXT(lcfg));
995 
996 	return (lcfg->duplicate_interval);
997 }
998 
999 isc_result_t
1000 isc_log_settag(isc_logconfig_t *lcfg, const char *tag) {
1001 	REQUIRE(VALID_CONFIG(lcfg));
1002 
1003 	if (tag != NULL && *tag != '\0') {
1004 		if (lcfg->tag != NULL)
1005 			isc_mem_free(lcfg->lctx->mctx, lcfg->tag);
1006 		lcfg->tag = isc_mem_strdup(lcfg->lctx->mctx, tag);
1007 		if (lcfg->tag == NULL)
1008 			return (ISC_R_NOMEMORY);
1009 
1010 	} else {
1011 		if (lcfg->tag != NULL)
1012 			isc_mem_free(lcfg->lctx->mctx, lcfg->tag);
1013 		lcfg->tag = NULL;
1014 	}
1015 
1016 	return (ISC_R_SUCCESS);
1017 }
1018 
1019 char *
1020 isc_log_gettag(isc_logconfig_t *lcfg) {
1021 	REQUIRE(VALID_CONFIG(lcfg));
1022 
1023 	return (lcfg->tag);
1024 }
1025 
1026 /* XXXDCL NT  -- This interface will assuredly be changing. */
1027 void
1028 isc_log_opensyslog(const char *tag, int options, int facility) {
1029 	(void)openlog(tag, options, facility);
1030 }
1031 
1032 void
1033 isc_log_closefilelogs(isc_log_t *lctx) {
1034 	isc_logchannel_t *channel;
1035 
1036 	REQUIRE(VALID_CONTEXT(lctx));
1037 
1038 	LOCK(&lctx->lock);
1039 	for (channel = ISC_LIST_HEAD(lctx->logconfig->channels);
1040 	     channel != NULL;
1041 	     channel = ISC_LIST_NEXT(channel, link))
1042 
1043 		if (channel->type == ISC_LOG_TOFILE &&
1044 		    FILE_STREAM(channel) != NULL) {
1045 			(void)fclose(FILE_STREAM(channel));
1046 			FILE_STREAM(channel) = NULL;
1047 		}
1048 	UNLOCK(&lctx->lock);
1049 }
1050 
1051 /****
1052  **** Internal functions
1053  ****/
1054 
1055 static isc_result_t
1056 assignchannel(isc_logconfig_t *lcfg, unsigned int category_id,
1057 	      const isc_logmodule_t *module, isc_logchannel_t *channel)
1058 {
1059 	isc_logchannellist_t *new_item;
1060 	isc_log_t *lctx;
1061 	isc_result_t result;
1062 
1063 	REQUIRE(VALID_CONFIG(lcfg));
1064 
1065 	lctx = lcfg->lctx;
1066 
1067 	REQUIRE(category_id < lctx->category_count);
1068 	REQUIRE(module == NULL || module->id < lctx->module_count);
1069 	REQUIRE(channel != NULL);
1070 
1071 	/*
1072 	 * Ensure lcfg->channellist_count == lctx->category_count.
1073 	 */
1074 	result = sync_channellist(lcfg);
1075 	if (result != ISC_R_SUCCESS)
1076 		return (result);
1077 
1078 	new_item = isc_mem_get(lctx->mctx, sizeof(*new_item));
1079 	if (new_item == NULL)
1080 		return (ISC_R_NOMEMORY);
1081 
1082 	new_item->channel = channel;
1083 	new_item->module = module;
1084 	ISC_LIST_INITANDPREPEND(lcfg->channellists[category_id],
1085 			       new_item, link);
1086 
1087 	/*
1088 	 * Remember the highest logging level set by any channel in the
1089 	 * logging config, so isc_log_doit() can quickly return if the
1090 	 * message is too high to be logged by any channel.
1091 	 */
1092 	if (channel->type != ISC_LOG_TONULL) {
1093 		if (lcfg->highest_level < channel->level)
1094 			lcfg->highest_level = channel->level;
1095 		if (channel->level == ISC_LOG_DYNAMIC)
1096 			lcfg->dynamic = ISC_TRUE;
1097 	}
1098 
1099 	return (ISC_R_SUCCESS);
1100 }
1101 
1102 /*
1103  * This would ideally be part of isc_log_registercategories(), except then
1104  * that function would have to return isc_result_t instead of void.
1105  */
1106 static isc_result_t
1107 sync_channellist(isc_logconfig_t *lcfg) {
1108 	unsigned int bytes;
1109 	isc_log_t *lctx;
1110 	void *lists;
1111 
1112 	REQUIRE(VALID_CONFIG(lcfg));
1113 
1114 	lctx = lcfg->lctx;
1115 
1116 	REQUIRE(lctx->category_count != 0);
1117 
1118 	if (lctx->category_count == lcfg->channellist_count)
1119 		return (ISC_R_SUCCESS);
1120 
1121 	bytes = lctx->category_count * sizeof(ISC_LIST(isc_logchannellist_t));
1122 
1123 	lists = isc_mem_get(lctx->mctx, bytes);
1124 
1125 	if (lists == NULL)
1126 		return (ISC_R_NOMEMORY);
1127 
1128 	memset(lists, 0, bytes);
1129 
1130 	if (lcfg->channellist_count != 0) {
1131 		bytes = lcfg->channellist_count *
1132 			sizeof(ISC_LIST(isc_logchannellist_t));
1133 		memcpy(lists, lcfg->channellists, bytes);
1134 		isc_mem_put(lctx->mctx, lcfg->channellists, bytes);
1135 	}
1136 
1137 	lcfg->channellists = lists;
1138 	lcfg->channellist_count = lctx->category_count;
1139 
1140 	return (ISC_R_SUCCESS);
1141 }
1142 
1143 static isc_result_t
1144 greatest_version(isc_logchannel_t *channel, int *greatestp) {
1145 	/* XXXDCL HIGHLY NT */
1146 	char *basenam, *digit_end;
1147 	const char *dirname;
1148 	int version, greatest = -1;
1149 	size_t basenamelen;
1150 	isc_dir_t dir;
1151 	isc_result_t result;
1152 	char sep = '/';
1153 #ifdef _WIN32
1154 	char *basename2;
1155 #endif
1156 
1157 	REQUIRE(channel->type == ISC_LOG_TOFILE);
1158 
1159 	/*
1160 	 * It is safe to DE_CONST the file.name because it was copied
1161 	 * with isc_mem_strdup in isc_log_createchannel.
1162 	 */
1163 	basenam = strrchr(FILE_NAME(channel), sep);
1164 #ifdef _WIN32
1165 	basename2 = strrchr(FILE_NAME(channel), '\\');
1166 	if ((basenam != NULL && basename2 != NULL && basename2 > basenam) ||
1167 	    (basenam == NULL && basename2 != NULL)) {
1168 		basenam = basename2;
1169 		sep = '\\';
1170 	}
1171 #endif
1172 	if (basenam != NULL) {
1173 		*basenam++ = '\0';
1174 		dirname = FILE_NAME(channel);
1175 	} else {
1176 		DE_CONST(FILE_NAME(channel), basenam);
1177 		dirname = ".";
1178 	}
1179 	basenamelen = strlen(basenam);
1180 
1181 	isc_dir_init(&dir);
1182 	result = isc_dir_open(&dir, dirname);
1183 
1184 	/*
1185 	 * Replace the file separator if it was taken out.
1186 	 */
1187 	if (basenam != FILE_NAME(channel))
1188 		*(basenam - 1) = sep;
1189 
1190 	/*
1191 	 * Return if the directory open failed.
1192 	 */
1193 	if (result != ISC_R_SUCCESS)
1194 		return (result);
1195 
1196 	while (isc_dir_read(&dir) == ISC_R_SUCCESS) {
1197 		if (dir.entry.length > basenamelen &&
1198 		    strncmp(dir.entry.name, basenam, basenamelen) == 0 &&
1199 		    dir.entry.name[basenamelen] == '.') {
1200 
1201 			version = strtol(&dir.entry.name[basenamelen + 1],
1202 					 &digit_end, 10);
1203 			if (*digit_end == '\0' && version > greatest)
1204 				greatest = version;
1205 		}
1206 	}
1207 	isc_dir_close(&dir);
1208 
1209 	*greatestp = ++greatest;
1210 
1211 	return (ISC_R_SUCCESS);
1212 }
1213 
1214 static isc_result_t
1215 roll_log(isc_logchannel_t *channel) {
1216 	int i, n, greatest;
1217 	char current[PATH_MAX + 1];
1218 	char new[PATH_MAX + 1];
1219 	const char *path;
1220 	isc_result_t result;
1221 
1222 	/*
1223 	 * Do nothing (not even excess version trimming) if ISC_LOG_ROLLNEVER
1224 	 * is specified.  Apparently complete external control over the log
1225 	 * files is desired.
1226 	 */
1227 	if (FILE_VERSIONS(channel) == ISC_LOG_ROLLNEVER)
1228 		return (ISC_R_SUCCESS);
1229 
1230 	path = FILE_NAME(channel);
1231 
1232 	/*
1233 	 * Set greatest_version to the greatest existing version
1234 	 * (not the maximum requested version).  This is 1 based even
1235 	 * though the file names are 0 based, so an oldest log of log.1
1236 	 * is a greatest_version of 2.
1237 	 */
1238 	result = greatest_version(channel, &greatest);
1239 	if (result != ISC_R_SUCCESS)
1240 		return (result);
1241 
1242 	/*
1243 	 * Now greatest should be set to the highest version number desired.
1244 	 * Since the highest number is one less than FILE_VERSIONS(channel)
1245 	 * when not doing infinite log rolling, greatest will need to be
1246 	 * decremented when it is equal to -- or greater than --
1247 	 * FILE_VERSIONS(channel).  When greatest is less than
1248 	 * FILE_VERSIONS(channel), it is already suitable for use as
1249 	 * the maximum version number.
1250 	 */
1251 
1252 	if (FILE_VERSIONS(channel) == ISC_LOG_ROLLINFINITE ||
1253 	    FILE_VERSIONS(channel) > greatest)
1254 		;		/* Do nothing. */
1255 	else
1256 		/*
1257 		 * When greatest is >= FILE_VERSIONS(channel), it needs to
1258 		 * be reduced until it is FILE_VERSIONS(channel) - 1.
1259 		 * Remove any excess logs on the way to that value.
1260 		 */
1261 		while (--greatest >= FILE_VERSIONS(channel)) {
1262 			n = snprintf(current, sizeof(current), "%s.%d",
1263 				     path, greatest);
1264 			if (n >= (int)sizeof(current) || n < 0)
1265 				result = ISC_R_NOSPACE;
1266 			else
1267 				result = isc_file_remove(current);
1268 			if (result != ISC_R_SUCCESS &&
1269 			    result != ISC_R_FILENOTFOUND)
1270 				syslog(LOG_ERR,
1271 				       "unable to remove log file '%s.%d': %s",
1272 				       path, greatest,
1273 				       isc_result_totext(result));
1274 		}
1275 
1276 	for (i = greatest; i > 0; i--) {
1277 		result = ISC_R_SUCCESS;
1278 		n = snprintf(current, sizeof(current), "%s.%d", path, i - 1);
1279 		if (n >= (int)sizeof(current) || n < 0)
1280 			result = ISC_R_NOSPACE;
1281 		if (result == ISC_R_SUCCESS) {
1282 			n = snprintf(new, sizeof(new), "%s.%d", path, i);
1283 			if (n >= (int)sizeof(new) || n < 0)
1284 				result = ISC_R_NOSPACE;
1285 		}
1286 		if (result == ISC_R_SUCCESS)
1287 			result = isc_file_rename(current, new);
1288 		if (result != ISC_R_SUCCESS &&
1289 		    result != ISC_R_FILENOTFOUND)
1290 			syslog(LOG_ERR,
1291 			       "unable to rename log file '%s.%d' to "
1292 			       "'%s.%d': %s", path, i - 1, path, i,
1293 			       isc_result_totext(result));
1294 	}
1295 
1296 	if (FILE_VERSIONS(channel) != 0) {
1297 		n = snprintf(new, sizeof(new), "%s.0", path);
1298 		if (n >= (int)sizeof(new) || n < 0)
1299 			result = ISC_R_NOSPACE;
1300 		else
1301 			result = isc_file_rename(path, new);
1302 		if (result != ISC_R_SUCCESS &&
1303 		    result != ISC_R_FILENOTFOUND)
1304 			syslog(LOG_ERR,
1305 			       "unable to rename log file '%s' to '%s.0': %s",
1306 			       path, path, isc_result_totext(result));
1307 	} else {
1308 		result = isc_file_remove(path);
1309 		if (result != ISC_R_SUCCESS &&
1310 		    result != ISC_R_FILENOTFOUND)
1311 			syslog(LOG_ERR, "unable to remove log file '%s': %s",
1312 			       path, isc_result_totext(result));
1313 	}
1314 
1315 	return (ISC_R_SUCCESS);
1316 }
1317 
1318 static isc_result_t
1319 isc_log_open(isc_logchannel_t *channel) {
1320 	struct stat statbuf;
1321 	isc_boolean_t regular_file;
1322 	isc_boolean_t roll = ISC_FALSE;
1323 	isc_result_t result = ISC_R_SUCCESS;
1324 	const char *path;
1325 
1326 	REQUIRE(channel->type == ISC_LOG_TOFILE);
1327 	REQUIRE(FILE_STREAM(channel) == NULL);
1328 
1329 	path = FILE_NAME(channel);
1330 
1331 	REQUIRE(path != NULL && *path != '\0');
1332 
1333 	/*
1334 	 * Determine type of file; only regular files will be
1335 	 * version renamed, and only if the base file exists
1336 	 * and either has no size limit or has reached its size limit.
1337 	 */
1338 	if (stat(path, &statbuf) == 0) {
1339 		regular_file = S_ISREG(statbuf.st_mode) ? ISC_TRUE : ISC_FALSE;
1340 		/* XXXDCL if not regular_file complain? */
1341 		if ((FILE_MAXSIZE(channel) == 0 &&
1342 		     FILE_VERSIONS(channel) != ISC_LOG_ROLLNEVER) ||
1343 		    (FILE_MAXSIZE(channel) > 0 &&
1344 		     statbuf.st_size >= FILE_MAXSIZE(channel)))
1345 			roll = regular_file;
1346 	} else if (errno == ENOENT) {
1347 		regular_file = ISC_TRUE;
1348 		POST(regular_file);
1349 	} else
1350 		result = ISC_R_INVALIDFILE;
1351 
1352 	/*
1353 	 * Version control.
1354 	 */
1355 	if (result == ISC_R_SUCCESS && roll) {
1356 		if (FILE_VERSIONS(channel) == ISC_LOG_ROLLNEVER)
1357 			return (ISC_R_MAXSIZE);
1358 		result = roll_log(channel);
1359 		if (result != ISC_R_SUCCESS) {
1360 			if ((channel->flags & ISC_LOG_OPENERR) == 0) {
1361 				syslog(LOG_ERR,
1362 				       "isc_log_open: roll_log '%s' "
1363 				       "failed: %s",
1364 				       FILE_NAME(channel),
1365 				       isc_result_totext(result));
1366 				channel->flags |= ISC_LOG_OPENERR;
1367 			}
1368 			return (result);
1369 		}
1370 	}
1371 
1372 	result = isc_stdio_open(path, "a", &FILE_STREAM(channel));
1373 
1374 	return (result);
1375 }
1376 
1377 isc_boolean_t
1378 isc_log_wouldlog(isc_log_t *lctx, int level) {
1379 	/*
1380 	 * Try to avoid locking the mutex for messages which can't
1381 	 * possibly be logged to any channels -- primarily debugging
1382 	 * messages that the debug level is not high enough to print.
1383 	 *
1384 	 * If the level is (mathematically) less than or equal to the
1385 	 * highest_level, or if there is a dynamic channel and the level is
1386 	 * less than or equal to the debug level, the main loop must be
1387 	 * entered to see if the message should really be output.
1388 	 *
1389 	 * NOTE: this is UNLOCKED access to the logconfig.  However,
1390 	 * the worst thing that can happen is that a bad decision is made
1391 	 * about returning without logging, and that's not a big concern,
1392 	 * because that's a risk anyway if the logconfig is being
1393 	 * dynamically changed.
1394 	 */
1395 
1396 	if (lctx == NULL || lctx->logconfig == NULL)
1397 		return (ISC_FALSE);
1398 
1399 	return (ISC_TF(level <= lctx->logconfig->highest_level ||
1400 		       (lctx->logconfig->dynamic &&
1401 			level <= lctx->debug_level)));
1402 }
1403 
1404 static void
1405 isc_log_doit(isc_log_t *lctx, isc_logcategory_t *category,
1406 	     isc_logmodule_t *module, int level, isc_boolean_t write_once,
1407 	     isc_msgcat_t *msgcat, int msgset, int msg,
1408 	     const char *format, va_list args)
1409 {
1410 	int syslog_level;
1411 	char time_string[64];
1412 	char level_string[24];
1413 	size_t octets;
1414 	const char *iformat;
1415 	struct stat statbuf;
1416 	isc_boolean_t matched = ISC_FALSE;
1417 	isc_boolean_t printtime, printtag;
1418 	isc_boolean_t printcategory, printmodule, printlevel;
1419 	isc_logconfig_t *lcfg;
1420 	isc_logchannel_t *channel;
1421 	isc_logchannellist_t *category_channels;
1422 	isc_result_t result;
1423 
1424 	REQUIRE(lctx == NULL || VALID_CONTEXT(lctx));
1425 	REQUIRE(category != NULL);
1426 	REQUIRE(module != NULL);
1427 	REQUIRE(level != ISC_LOG_DYNAMIC);
1428 	REQUIRE(format != NULL);
1429 
1430 	/*
1431 	 * Programs can use libraries that use this logging code without
1432 	 * wanting to do any logging, thus the log context is allowed to
1433 	 * be non-existent.
1434 	 */
1435 	if (lctx == NULL)
1436 		return;
1437 
1438 	REQUIRE(category->id < lctx->category_count);
1439 	REQUIRE(module->id < lctx->module_count);
1440 
1441 	if (! isc_log_wouldlog(lctx, level))
1442 		return;
1443 
1444 	if (msgcat != NULL)
1445 		iformat = isc_msgcat_get(msgcat, msgset, msg, format);
1446 	else
1447 		iformat = format;
1448 
1449 	time_string[0]  = '\0';
1450 	level_string[0] = '\0';
1451 
1452 	LOCK(&lctx->lock);
1453 
1454 	lctx->buffer[0] = '\0';
1455 
1456 	lcfg = lctx->logconfig;
1457 
1458 	category_channels = ISC_LIST_HEAD(lcfg->channellists[category->id]);
1459 
1460 	/*
1461 	 * XXXDCL add duplicate filtering? (To not write multiple times to
1462 	 * the same source via various channels).
1463 	 */
1464 	do {
1465 		/*
1466 		 * If the channel list end was reached and a match was made,
1467 		 * everything is finished.
1468 		 */
1469 		if (category_channels == NULL && matched)
1470 			break;
1471 
1472 		if (category_channels == NULL && ! matched &&
1473 		    category_channels != ISC_LIST_HEAD(lcfg->channellists[0]))
1474 			/*
1475 			 * No category/module pair was explicitly configured.
1476 			 * Try the category named "default".
1477 			 */
1478 			category_channels =
1479 				ISC_LIST_HEAD(lcfg->channellists[0]);
1480 
1481 		if (category_channels == NULL && ! matched)
1482 			/*
1483 			 * No matching module was explicitly configured
1484 			 * for the category named "default".  Use the internal
1485 			 * default channel.
1486 			 */
1487 			category_channels = &default_channel;
1488 
1489 		if (category_channels->module != NULL &&
1490 		    category_channels->module != module) {
1491 			category_channels = ISC_LIST_NEXT(category_channels,
1492 							  link);
1493 			continue;
1494 		}
1495 
1496 		matched = ISC_TRUE;
1497 
1498 		channel = category_channels->channel;
1499 		category_channels = ISC_LIST_NEXT(category_channels, link);
1500 
1501 		if (((channel->flags & ISC_LOG_DEBUGONLY) != 0) &&
1502 		    lctx->debug_level == 0)
1503 			continue;
1504 
1505 		if (channel->level == ISC_LOG_DYNAMIC) {
1506 			if (lctx->debug_level < level)
1507 				continue;
1508 		} else if (channel->level < level)
1509 			continue;
1510 
1511 		if ((channel->flags & ISC_LOG_PRINTTIME) != 0 &&
1512 		    time_string[0] == '\0') {
1513 			isc_time_t isctime;
1514 
1515 			TIME_NOW(&isctime);
1516 			isc_time_formattimestamp(&isctime, time_string,
1517 						 sizeof(time_string));
1518 		}
1519 
1520 		if ((channel->flags & ISC_LOG_PRINTLEVEL) != 0 &&
1521 		    level_string[0] == '\0') {
1522 			if (level < ISC_LOG_CRITICAL)
1523 				snprintf(level_string, sizeof(level_string),
1524 					 "%s %d: ",
1525 					 isc_msgcat_get(isc_msgcat,
1526 							ISC_MSGSET_LOG,
1527 							ISC_MSG_LEVEL,
1528 							"level"),
1529 					 level);
1530 			else if (level > ISC_LOG_DYNAMIC)
1531 				snprintf(level_string, sizeof(level_string),
1532 					 "%s %d: ", log_level_strings[0],
1533 					 level);
1534 			else
1535 				snprintf(level_string, sizeof(level_string),
1536 					 "%s: ", log_level_strings[-level]);
1537 		}
1538 
1539 		/*
1540 		 * Only format the message once.
1541 		 */
1542 		if (lctx->buffer[0] == '\0') {
1543 			(void)vsnprintf(lctx->buffer, sizeof(lctx->buffer),
1544 					iformat, args);
1545 
1546 			/*
1547 			 * Check for duplicates.
1548 			 */
1549 			if (write_once) {
1550 				isc_logmessage_t *message, *new;
1551 				isc_time_t oldest;
1552 				isc_interval_t interval;
1553 
1554 				isc_interval_set(&interval,
1555 						 lcfg->duplicate_interval, 0);
1556 
1557 				/*
1558 				 * 'oldest' is the age of the oldest messages
1559 				 * which fall within the duplicate_interval
1560 				 * range.
1561 				 */
1562 				TIME_NOW(&oldest);
1563 				if (isc_time_subtract(&oldest, &interval, &oldest)
1564 				    != ISC_R_SUCCESS)
1565 					/*
1566 					 * Can't effectively do the checking
1567 					 * without having a valid time.
1568 					 */
1569 					message = NULL;
1570 				else
1571 					message =ISC_LIST_HEAD(lctx->messages);
1572 
1573 				while (message != NULL) {
1574 					if (isc_time_compare(&message->time,
1575 							     &oldest) < 0) {
1576 						/*
1577 						 * This message is older
1578 						 * than the duplicate_interval,
1579 						 * so it should be dropped from
1580 						 * the history.
1581 						 *
1582 						 * Setting the interval to be
1583 						 * to be longer will obviously
1584 						 * not cause the expired
1585 						 * message to spring back into
1586 						 * existence.
1587 						 */
1588 						new = ISC_LIST_NEXT(message,
1589 								    link);
1590 
1591 						ISC_LIST_UNLINK(lctx->messages,
1592 								message, link);
1593 
1594 						isc_mem_put(lctx->mctx,
1595 							message,
1596 							sizeof(*message) + 1 +
1597 							strlen(message->text));
1598 
1599 						message = new;
1600 						continue;
1601 					}
1602 
1603 					/*
1604 					 * This message is in the duplicate
1605 					 * filtering interval ...
1606 					 */
1607 					if (strcmp(lctx->buffer, message->text)
1608 					    == 0) {
1609 						/*
1610 						 * ... and it is a duplicate.
1611 						 * Unlock the mutex and
1612 						 * get the hell out of Dodge.
1613 						 */
1614 						UNLOCK(&lctx->lock);
1615 						return;
1616 					}
1617 
1618 					message = ISC_LIST_NEXT(message, link);
1619 				}
1620 
1621 				/*
1622 				 * It wasn't in the duplicate interval,
1623 				 * so add it to the message list.
1624 				 */
1625 				octets = strlen(lctx->buffer) + 1;
1626 				new = isc_mem_get(lctx->mctx,
1627 						  sizeof(isc_logmessage_t) +
1628 						  octets);
1629 				if (new != NULL) {
1630 					/*
1631 					 * Put the text immediately after
1632 					 * the struct.  The strcpy is safe.
1633 					 */
1634 					new->text = (char *)(new + 1);
1635 					strlcpy(new->text, lctx->buffer, octets);
1636 
1637 					TIME_NOW(&new->time);
1638 
1639 					ISC_LIST_APPEND(lctx->messages,
1640 							new, link);
1641 				}
1642 			}
1643 		}
1644 
1645 		printtime     = ISC_TF((channel->flags & ISC_LOG_PRINTTIME)
1646 				       != 0);
1647 		printtag      = ISC_TF((channel->flags & ISC_LOG_PRINTTAG)
1648 				       != 0 && lcfg->tag != NULL);
1649 		printcategory = ISC_TF((channel->flags & ISC_LOG_PRINTCATEGORY)
1650 				       != 0);
1651 		printmodule   = ISC_TF((channel->flags & ISC_LOG_PRINTMODULE)
1652 				       != 0);
1653 		printlevel    = ISC_TF((channel->flags & ISC_LOG_PRINTLEVEL)
1654 				       != 0);
1655 
1656 		switch (channel->type) {
1657 		case ISC_LOG_TOFILE:
1658 			if (FILE_MAXREACHED(channel)) {
1659 				/*
1660 				 * If the file can be rolled, OR
1661 				 * If the file no longer exists, OR
1662 				 * If the file is less than the maximum size,
1663 				 *    (such as if it had been renamed and
1664 				 *     a new one touched, or it was truncated
1665 				 *     in place)
1666 				 * ... then close it to trigger reopening.
1667 				 */
1668 				if (FILE_VERSIONS(channel) !=
1669 				    ISC_LOG_ROLLNEVER ||
1670 				    (stat(FILE_NAME(channel), &statbuf) != 0 &&
1671 				     errno == ENOENT) ||
1672 				    statbuf.st_size < FILE_MAXSIZE(channel)) {
1673 					(void)fclose(FILE_STREAM(channel));
1674 					FILE_STREAM(channel) = NULL;
1675 					FILE_MAXREACHED(channel) = ISC_FALSE;
1676 				} else
1677 					/*
1678 					 * Eh, skip it.
1679 					 */
1680 					break;
1681 			}
1682 
1683 			if (FILE_STREAM(channel) == NULL) {
1684 				result = isc_log_open(channel);
1685 				if (result != ISC_R_SUCCESS &&
1686 				    result != ISC_R_MAXSIZE &&
1687 				    (channel->flags & ISC_LOG_OPENERR) == 0) {
1688 					syslog(LOG_ERR,
1689 					       "isc_log_open '%s' failed: %s",
1690 					       FILE_NAME(channel),
1691 					       isc_result_totext(result));
1692 					channel->flags |= ISC_LOG_OPENERR;
1693 				}
1694 				if (result != ISC_R_SUCCESS)
1695 					break;
1696 				channel->flags &= ~ISC_LOG_OPENERR;
1697 			}
1698 			/* FALLTHROUGH */
1699 
1700 		case ISC_LOG_TOFILEDESC:
1701 			fprintf(FILE_STREAM(channel), "%s%s%s%s%s%s%s%s%s%s\n",
1702 				printtime     ? time_string	: "",
1703 				printtime     ? " "		: "",
1704 				printtag      ? lcfg->tag	: "",
1705 				printtag      ? ": "		: "",
1706 				printcategory ? category->name	: "",
1707 				printcategory ? ": "		: "",
1708 				printmodule   ? (module != NULL ? module->name
1709 								: "no_module")
1710 								: "",
1711 				printmodule   ? ": "		: "",
1712 				printlevel    ? level_string	: "",
1713 				lctx->buffer);
1714 
1715 			fflush(FILE_STREAM(channel));
1716 
1717 			/*
1718 			 * If the file now exceeds its maximum size
1719 			 * threshold, note it so that it will not be logged
1720 			 * to any more.
1721 			 */
1722 			if (FILE_MAXSIZE(channel) > 0) {
1723 				INSIST(channel->type == ISC_LOG_TOFILE);
1724 
1725 				/* XXXDCL NT fstat/fileno */
1726 				/* XXXDCL complain if fstat fails? */
1727 				if (fstat(fileno(FILE_STREAM(channel)),
1728 					  &statbuf) >= 0 &&
1729 				    statbuf.st_size > FILE_MAXSIZE(channel))
1730 					FILE_MAXREACHED(channel) = ISC_TRUE;
1731 			}
1732 
1733 			break;
1734 
1735 		case ISC_LOG_TOSYSLOG:
1736 			if (level > 0)
1737 				syslog_level = LOG_DEBUG;
1738 			else if (level < ISC_LOG_CRITICAL)
1739 				syslog_level = LOG_CRIT;
1740 			else
1741 				syslog_level = syslog_map[-level];
1742 
1743 			(void)syslog(FACILITY(channel) | syslog_level,
1744 			       "%s%s%s%s%s%s%s%s%s%s",
1745 			       printtime     ? time_string	: "",
1746 			       printtime     ? " "		: "",
1747 			       printtag      ? lcfg->tag	: "",
1748 			       printtag      ? ": "		: "",
1749 			       printcategory ? category->name	: "",
1750 			       printcategory ? ": "		: "",
1751 			       printmodule   ? (module != NULL	? module->name
1752 								: "no_module")
1753 								: "",
1754 			       printmodule   ? ": "		: "",
1755 			       printlevel    ? level_string	: "",
1756 			       lctx->buffer);
1757 			break;
1758 
1759 		case ISC_LOG_TONULL:
1760 			break;
1761 
1762 		}
1763 
1764 	} while (1);
1765 
1766 	UNLOCK(&lctx->lock);
1767 }
1768