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log.c revision 1.10
      1 /*	$NetBSD: log.c,v 1.10 2024/02/21 22:52:28 christos Exp $	*/
      2 
      3 /*
      4  * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
      5  *
      6  * SPDX-License-Identifier: MPL-2.0
      7  *
      8  * This Source Code Form is subject to the terms of the Mozilla Public
      9  * License, v. 2.0. If a copy of the MPL was not distributed with this
     10  * file, you can obtain one at https://mozilla.org/MPL/2.0/.
     11  *
     12  * See the COPYRIGHT file distributed with this work for additional
     13  * information regarding copyright ownership.
     14  */
     15 
     16 /*! \file */
     17 
     18 #include <errno.h>
     19 #include <inttypes.h>
     20 #include <limits.h>
     21 #include <stdbool.h>
     22 #include <stdlib.h>
     23 #include <sys/types.h> /* dev_t FreeBSD 2.1 */
     24 #include <time.h>
     25 #include <unistd.h>
     26 
     27 #include <isc/atomic.h>
     28 #include <isc/dir.h>
     29 #include <isc/errno.h>
     30 #include <isc/file.h>
     31 #include <isc/log.h>
     32 #include <isc/magic.h>
     33 #include <isc/mem.h>
     34 #include <isc/print.h>
     35 #include <isc/rwlock.h>
     36 #include <isc/stat.h>
     37 #include <isc/stdio.h>
     38 #include <isc/string.h>
     39 #include <isc/thread.h>
     40 #include <isc/time.h>
     41 #include <isc/util.h>
     42 
     43 #define LCTX_MAGIC	    ISC_MAGIC('L', 'c', 't', 'x')
     44 #define VALID_CONTEXT(lctx) ISC_MAGIC_VALID(lctx, LCTX_MAGIC)
     45 
     46 #define LCFG_MAGIC	   ISC_MAGIC('L', 'c', 'f', 'g')
     47 #define VALID_CONFIG(lcfg) ISC_MAGIC_VALID(lcfg, LCFG_MAGIC)
     48 
     49 #define RDLOCK(lp)   RWLOCK(lp, isc_rwlocktype_read);
     50 #define WRLOCK(lp)   RWLOCK(lp, isc_rwlocktype_write);
     51 #define RDUNLOCK(lp) RWUNLOCK(lp, isc_rwlocktype_read);
     52 #define WRUNLOCK(lp) RWUNLOCK(lp, isc_rwlocktype_write);
     53 
     54 static thread_local bool forcelog = false;
     55 
     56 /*
     57  * XXXDCL make dynamic?
     58  */
     59 #define LOG_BUFFER_SIZE (8 * 1024)
     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_fast32_t highest_level;
    124 	char *tag;
    125 	bool 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 	atomic_int_fast32_t debug_level;
    154 	isc_rwlock_t lcfg_rwl;
    155 	/* Locked by isc_log lcfg_rwl */
    156 	isc_logconfig_t *logconfig;
    157 	isc_mutex_t lock;
    158 	/* Locked by isc_log lock. */
    159 	char buffer[LOG_BUFFER_SIZE];
    160 	ISC_LIST(isc_logmessage_t) messages;
    161 	atomic_bool dynamic;
    162 	atomic_int_fast32_t highest_level;
    163 };
    164 
    165 /*!
    166  * Used when ISC_LOG_PRINTLEVEL is enabled for a channel.
    167  */
    168 static const char *log_level_strings[] = { "debug",   "info",  "notice",
    169 					   "warning", "error", "critical" };
    170 
    171 /*!
    172  * Used to convert ISC_LOG_* priorities into syslog priorities.
    173  * XXXDCL This will need modification for NT.
    174  */
    175 static const int syslog_map[] = { LOG_DEBUG,   LOG_INFO, LOG_NOTICE,
    176 				  LOG_WARNING, LOG_ERR,	 LOG_CRIT };
    177 
    178 /*!
    179  * When adding new categories, a corresponding ISC_LOGCATEGORY_foo
    180  * definition needs to be added to <isc/log.h>.
    181  *
    182  * The default category is provided so that the internal default can
    183  * be overridden.  Since the default is always looked up as the first
    184  * channellist in the log context, it must come first in isc_categories[].
    185  */
    186 isc_logcategory_t isc_categories[] = { { "default", 0 }, /* "default
    187 							    must come
    188 							    first. */
    189 				       { "general", 0 },
    190 				       { "sslkeylog", 0 },
    191 				       { NULL, 0 } };
    192 
    193 /*!
    194  * See above comment for categories, and apply it to modules.
    195  */
    196 isc_logmodule_t isc_modules[] = { { "socket", 0 },    { "time", 0 },
    197 				  { "interface", 0 }, { "timer", 0 },
    198 				  { "file", 0 },      { "netmgr", 0 },
    199 				  { "other", 0 },     { NULL, 0 } };
    200 
    201 /*!
    202  * This essentially constant structure must be filled in at run time,
    203  * because its channel member is pointed to a channel that is created
    204  * dynamically with isc_log_createchannel.
    205  */
    206 static isc_logchannellist_t default_channel;
    207 
    208 /*!
    209  * libisc logs to this context.
    210  */
    211 isc_log_t *isc_lctx = NULL;
    212 
    213 /*!
    214  * Forward declarations.
    215  */
    216 static void
    217 assignchannel(isc_logconfig_t *lcfg, unsigned int category_id,
    218 	      const isc_logmodule_t *module, isc_logchannel_t *channel);
    219 
    220 static void
    221 sync_channellist(isc_logconfig_t *lcfg);
    222 
    223 static void
    224 sync_highest_level(isc_log_t *lctx, isc_logconfig_t *lcfg);
    225 
    226 static isc_result_t
    227 greatest_version(isc_logfile_t *file, int versions, int *greatest);
    228 
    229 static void
    230 isc_log_doit(isc_log_t *lctx, isc_logcategory_t *category,
    231 	     isc_logmodule_t *module, int level, bool write_once,
    232 	     const char *format, va_list args) ISC_FORMAT_PRINTF(6, 0);
    233 
    234 /*@{*/
    235 /*!
    236  * Convenience macros.
    237  */
    238 
    239 #define FACILITY(channel)	 (channel->destination.facility)
    240 #define FILE_NAME(channel)	 (channel->destination.file.name)
    241 #define FILE_STREAM(channel)	 (channel->destination.file.stream)
    242 #define FILE_VERSIONS(channel)	 (channel->destination.file.versions)
    243 #define FILE_SUFFIX(channel)	 (channel->destination.file.suffix)
    244 #define FILE_MAXSIZE(channel)	 (channel->destination.file.maximum_size)
    245 #define FILE_MAXREACHED(channel) (channel->destination.file.maximum_reached)
    246 
    247 /*@}*/
    248 /****
    249 **** Public interfaces.
    250 ****/
    251 
    252 /*
    253  * Establish a new logging context, with default channels.
    254  */
    255 void
    256 isc_log_create(isc_mem_t *mctx, isc_log_t **lctxp, isc_logconfig_t **lcfgp) {
    257 	isc_log_t *lctx;
    258 	isc_logconfig_t *lcfg = NULL;
    259 
    260 	REQUIRE(mctx != NULL);
    261 	REQUIRE(lctxp != NULL && *lctxp == NULL);
    262 	REQUIRE(lcfgp == NULL || *lcfgp == NULL);
    263 
    264 	lctx = isc_mem_get(mctx, sizeof(*lctx));
    265 	lctx->mctx = NULL;
    266 	isc_mem_attach(mctx, &lctx->mctx);
    267 	lctx->categories = NULL;
    268 	lctx->category_count = 0;
    269 	lctx->modules = NULL;
    270 	lctx->module_count = 0;
    271 	atomic_init(&lctx->debug_level, 0);
    272 
    273 	ISC_LIST_INIT(lctx->messages);
    274 
    275 	isc_mutex_init(&lctx->lock);
    276 	isc_rwlock_init(&lctx->lcfg_rwl, 0, 0);
    277 
    278 	/*
    279 	 * Normally setting the magic number is the last step done
    280 	 * in a creation function, but a valid log context is needed
    281 	 * by isc_log_registercategories and isc_logconfig_create.
    282 	 * If either fails, the lctx is destroyed and not returned
    283 	 * to the caller.
    284 	 */
    285 	lctx->magic = LCTX_MAGIC;
    286 
    287 	isc_log_registercategories(lctx, isc_categories);
    288 	isc_log_registermodules(lctx, isc_modules);
    289 	isc_logconfig_create(lctx, &lcfg);
    290 
    291 	sync_channellist(lcfg);
    292 
    293 	lctx->logconfig = lcfg;
    294 
    295 	atomic_init(&lctx->highest_level, lcfg->highest_level);
    296 	atomic_init(&lctx->dynamic, lcfg->dynamic);
    297 
    298 	*lctxp = lctx;
    299 	if (lcfgp != NULL) {
    300 		*lcfgp = lcfg;
    301 	}
    302 }
    303 
    304 void
    305 isc_logconfig_create(isc_log_t *lctx, isc_logconfig_t **lcfgp) {
    306 	isc_logconfig_t *lcfg;
    307 	isc_logdestination_t destination;
    308 	int level = ISC_LOG_INFO;
    309 
    310 	REQUIRE(lcfgp != NULL && *lcfgp == NULL);
    311 	REQUIRE(VALID_CONTEXT(lctx));
    312 
    313 	lcfg = isc_mem_get(lctx->mctx, sizeof(*lcfg));
    314 
    315 	lcfg->lctx = lctx;
    316 	lcfg->channellists = NULL;
    317 	lcfg->channellist_count = 0;
    318 	lcfg->duplicate_interval = 0;
    319 	lcfg->highest_level = level;
    320 	lcfg->tag = NULL;
    321 	lcfg->dynamic = false;
    322 	ISC_LIST_INIT(lcfg->channels);
    323 	lcfg->magic = LCFG_MAGIC;
    324 
    325 	/*
    326 	 * Create the default channels:
    327 	 *      default_syslog, default_stderr, default_debug and null.
    328 	 */
    329 	destination.facility = LOG_DAEMON;
    330 	isc_log_createchannel(lcfg, "default_syslog", ISC_LOG_TOSYSLOG, level,
    331 			      &destination, 0);
    332 
    333 	destination.file.stream = stderr;
    334 	destination.file.name = NULL;
    335 	destination.file.versions = ISC_LOG_ROLLNEVER;
    336 	destination.file.suffix = isc_log_rollsuffix_increment;
    337 	destination.file.maximum_size = 0;
    338 	isc_log_createchannel(lcfg, "default_stderr", ISC_LOG_TOFILEDESC, level,
    339 			      &destination, ISC_LOG_PRINTTIME);
    340 
    341 	/*
    342 	 * Set the default category's channel to default_stderr,
    343 	 * which is at the head of the channels list because it was
    344 	 * just created.
    345 	 */
    346 	default_channel.channel = ISC_LIST_HEAD(lcfg->channels);
    347 
    348 	destination.file.stream = stderr;
    349 	destination.file.name = NULL;
    350 	destination.file.versions = ISC_LOG_ROLLNEVER;
    351 	destination.file.suffix = isc_log_rollsuffix_increment;
    352 	destination.file.maximum_size = 0;
    353 	isc_log_createchannel(lcfg, "default_debug", ISC_LOG_TOFILEDESC,
    354 			      ISC_LOG_DYNAMIC, &destination, ISC_LOG_PRINTTIME);
    355 
    356 	isc_log_createchannel(lcfg, "null", ISC_LOG_TONULL, ISC_LOG_DYNAMIC,
    357 			      NULL, 0);
    358 
    359 	*lcfgp = lcfg;
    360 }
    361 
    362 void
    363 isc_logconfig_use(isc_log_t *lctx, isc_logconfig_t *lcfg) {
    364 	isc_logconfig_t *old_cfg;
    365 
    366 	REQUIRE(VALID_CONTEXT(lctx));
    367 	REQUIRE(VALID_CONFIG(lcfg));
    368 	REQUIRE(lcfg->lctx == lctx);
    369 
    370 	/*
    371 	 * Ensure that lcfg->channellist_count == lctx->category_count.
    372 	 * They won't be equal if isc_log_usechannel has not been called
    373 	 * since any call to isc_log_registercategories.
    374 	 */
    375 	sync_channellist(lcfg);
    376 
    377 	WRLOCK(&lctx->lcfg_rwl);
    378 	old_cfg = lctx->logconfig;
    379 	lctx->logconfig = lcfg;
    380 	sync_highest_level(lctx, lcfg);
    381 	WRUNLOCK(&lctx->lcfg_rwl);
    382 
    383 	isc_logconfig_destroy(&old_cfg);
    384 }
    385 
    386 void
    387 isc_log_destroy(isc_log_t **lctxp) {
    388 	isc_log_t *lctx;
    389 	isc_logconfig_t *lcfg;
    390 	isc_mem_t *mctx;
    391 	isc_logmessage_t *message;
    392 
    393 	REQUIRE(lctxp != NULL && VALID_CONTEXT(*lctxp));
    394 
    395 	lctx = *lctxp;
    396 	*lctxp = NULL;
    397 	mctx = lctx->mctx;
    398 
    399 	/* Stop the logging as a first thing */
    400 	atomic_store_release(&lctx->debug_level, 0);
    401 	atomic_store_release(&lctx->highest_level, 0);
    402 	atomic_store_release(&lctx->dynamic, false);
    403 
    404 	WRLOCK(&lctx->lcfg_rwl);
    405 	lcfg = lctx->logconfig;
    406 	lctx->logconfig = NULL;
    407 	WRUNLOCK(&lctx->lcfg_rwl);
    408 
    409 	if (lcfg != NULL) {
    410 		isc_logconfig_destroy(&lcfg);
    411 	}
    412 
    413 	isc_rwlock_destroy(&lctx->lcfg_rwl);
    414 	isc_mutex_destroy(&lctx->lock);
    415 
    416 	while ((message = ISC_LIST_HEAD(lctx->messages)) != NULL) {
    417 		ISC_LIST_UNLINK(lctx->messages, message, link);
    418 
    419 		isc_mem_put(mctx, message,
    420 			    sizeof(*message) + strlen(message->text) + 1);
    421 	}
    422 
    423 	lctx->buffer[0] = '\0';
    424 	lctx->categories = NULL;
    425 	lctx->category_count = 0;
    426 	lctx->modules = NULL;
    427 	lctx->module_count = 0;
    428 	lctx->mctx = NULL;
    429 	lctx->magic = 0;
    430 
    431 	isc_mem_putanddetach(&mctx, lctx, sizeof(*lctx));
    432 }
    433 
    434 void
    435 isc_logconfig_destroy(isc_logconfig_t **lcfgp) {
    436 	isc_logconfig_t *lcfg;
    437 	isc_mem_t *mctx;
    438 	isc_logchannel_t *channel;
    439 	char *filename;
    440 	unsigned int i;
    441 
    442 	REQUIRE(lcfgp != NULL && VALID_CONFIG(*lcfgp));
    443 
    444 	lcfg = *lcfgp;
    445 	*lcfgp = NULL;
    446 
    447 	/*
    448 	 * This function cannot be called with a logconfig that is in
    449 	 * use by a log context.
    450 	 */
    451 	REQUIRE(lcfg->lctx != NULL);
    452 
    453 	RDLOCK(&lcfg->lctx->lcfg_rwl);
    454 	REQUIRE(lcfg->lctx->logconfig != lcfg);
    455 	RDUNLOCK(&lcfg->lctx->lcfg_rwl);
    456 
    457 	mctx = lcfg->lctx->mctx;
    458 
    459 	while ((channel = ISC_LIST_HEAD(lcfg->channels)) != NULL) {
    460 		ISC_LIST_UNLINK(lcfg->channels, channel, link);
    461 
    462 		if (channel->type == ISC_LOG_TOFILE) {
    463 			/*
    464 			 * The filename for the channel may have ultimately
    465 			 * started its life in user-land as a const string,
    466 			 * but in isc_log_createchannel it gets copied
    467 			 * into writable memory and is not longer truly const.
    468 			 */
    469 			DE_CONST(FILE_NAME(channel), filename);
    470 			isc_mem_free(mctx, filename);
    471 
    472 			if (FILE_STREAM(channel) != NULL) {
    473 				(void)fclose(FILE_STREAM(channel));
    474 			}
    475 		}
    476 
    477 		isc_mem_free(mctx, channel->name);
    478 		isc_mem_put(mctx, channel, sizeof(*channel));
    479 	}
    480 
    481 	for (i = 0; i < lcfg->channellist_count; i++) {
    482 		isc_logchannellist_t *item;
    483 		while ((item = ISC_LIST_HEAD(lcfg->channellists[i])) != NULL) {
    484 			ISC_LIST_UNLINK(lcfg->channellists[i], item, link);
    485 			isc_mem_put(mctx, item, sizeof(*item));
    486 		}
    487 	}
    488 
    489 	if (lcfg->channellist_count > 0) {
    490 		isc_mem_put(mctx, lcfg->channellists,
    491 			    lcfg->channellist_count *
    492 				    sizeof(ISC_LIST(isc_logchannellist_t)));
    493 	}
    494 
    495 	lcfg->dynamic = false;
    496 	if (lcfg->tag != NULL) {
    497 		isc_mem_free(lcfg->lctx->mctx, lcfg->tag);
    498 	}
    499 	lcfg->tag = NULL;
    500 	lcfg->highest_level = 0;
    501 	lcfg->duplicate_interval = 0;
    502 	lcfg->magic = 0;
    503 
    504 	isc_mem_put(mctx, lcfg, sizeof(*lcfg));
    505 }
    506 
    507 void
    508 isc_log_registercategories(isc_log_t *lctx, isc_logcategory_t categories[]) {
    509 	isc_logcategory_t *catp;
    510 
    511 	REQUIRE(VALID_CONTEXT(lctx));
    512 	REQUIRE(categories != NULL && categories[0].name != NULL);
    513 
    514 	/*
    515 	 * XXXDCL This somewhat sleazy situation of using the last pointer
    516 	 * in one category array to point to the next array exists because
    517 	 * this registration function returns void and I didn't want to have
    518 	 * change everything that used it by making it return an isc_result_t.
    519 	 * It would need to do that if it had to allocate memory to store
    520 	 * pointers to each array passed in.
    521 	 */
    522 	if (lctx->categories == NULL) {
    523 		lctx->categories = categories;
    524 	} else {
    525 		/*
    526 		 * Adjust the last (NULL) pointer of the already registered
    527 		 * categories to point to the incoming array.
    528 		 */
    529 		for (catp = lctx->categories; catp->name != NULL;) {
    530 			if (catp->id == UINT_MAX) {
    531 				/*
    532 				 * The name pointer points to the next array.
    533 				 * Ick.
    534 				 */
    535 				DE_CONST(catp->name, catp);
    536 			} else {
    537 				catp++;
    538 			}
    539 		}
    540 
    541 		catp->name = (void *)categories;
    542 		catp->id = UINT_MAX;
    543 	}
    544 
    545 	/*
    546 	 * Update the id number of the category with its new global id.
    547 	 */
    548 	for (catp = categories; catp->name != NULL; catp++) {
    549 		catp->id = lctx->category_count++;
    550 	}
    551 }
    552 
    553 isc_logcategory_t *
    554 isc_log_categorybyname(isc_log_t *lctx, const char *name) {
    555 	isc_logcategory_t *catp;
    556 
    557 	REQUIRE(VALID_CONTEXT(lctx));
    558 	REQUIRE(name != NULL);
    559 
    560 	for (catp = lctx->categories; catp->name != NULL;) {
    561 		if (catp->id == UINT_MAX) {
    562 			/*
    563 			 * catp is neither modified nor returned to the
    564 			 * caller, so removing its const qualifier is ok.
    565 			 */
    566 			DE_CONST(catp->name, catp);
    567 		} else {
    568 			if (strcmp(catp->name, name) == 0) {
    569 				return (catp);
    570 			}
    571 			catp++;
    572 		}
    573 	}
    574 
    575 	return (NULL);
    576 }
    577 
    578 void
    579 isc_log_registermodules(isc_log_t *lctx, isc_logmodule_t modules[]) {
    580 	isc_logmodule_t *modp;
    581 
    582 	REQUIRE(VALID_CONTEXT(lctx));
    583 	REQUIRE(modules != NULL && modules[0].name != NULL);
    584 
    585 	/*
    586 	 * XXXDCL This somewhat sleazy situation of using the last pointer
    587 	 * in one category array to point to the next array exists because
    588 	 * this registration function returns void and I didn't want to have
    589 	 * change everything that used it by making it return an isc_result_t.
    590 	 * It would need to do that if it had to allocate memory to store
    591 	 * pointers to each array passed in.
    592 	 */
    593 	if (lctx->modules == NULL) {
    594 		lctx->modules = modules;
    595 	} else {
    596 		/*
    597 		 * Adjust the last (NULL) pointer of the already registered
    598 		 * modules to point to the incoming array.
    599 		 */
    600 		for (modp = lctx->modules; modp->name != NULL;) {
    601 			if (modp->id == UINT_MAX) {
    602 				/*
    603 				 * The name pointer points to the next array.
    604 				 * Ick.
    605 				 */
    606 				DE_CONST(modp->name, modp);
    607 			} else {
    608 				modp++;
    609 			}
    610 		}
    611 
    612 		modp->name = (void *)modules;
    613 		modp->id = UINT_MAX;
    614 	}
    615 
    616 	/*
    617 	 * Update the id number of the module with its new global id.
    618 	 */
    619 	for (modp = modules; modp->name != NULL; modp++) {
    620 		modp->id = lctx->module_count++;
    621 	}
    622 }
    623 
    624 isc_logmodule_t *
    625 isc_log_modulebyname(isc_log_t *lctx, const char *name) {
    626 	isc_logmodule_t *modp;
    627 
    628 	REQUIRE(VALID_CONTEXT(lctx));
    629 	REQUIRE(name != NULL);
    630 
    631 	for (modp = lctx->modules; modp->name != NULL;) {
    632 		if (modp->id == UINT_MAX) {
    633 			/*
    634 			 * modp is neither modified nor returned to the
    635 			 * caller, so removing its const qualifier is ok.
    636 			 */
    637 			DE_CONST(modp->name, modp);
    638 		} else {
    639 			if (strcmp(modp->name, name) == 0) {
    640 				return (modp);
    641 			}
    642 			modp++;
    643 		}
    644 	}
    645 
    646 	return (NULL);
    647 }
    648 
    649 void
    650 isc_log_createchannel(isc_logconfig_t *lcfg, const char *name,
    651 		      unsigned int type, int level,
    652 		      const isc_logdestination_t *destination,
    653 		      unsigned int flags) {
    654 	isc_logchannel_t *channel;
    655 	isc_mem_t *mctx;
    656 	unsigned int permitted = ISC_LOG_PRINTALL | ISC_LOG_DEBUGONLY |
    657 				 ISC_LOG_BUFFERED | ISC_LOG_ISO8601 |
    658 				 ISC_LOG_UTC;
    659 
    660 	REQUIRE(VALID_CONFIG(lcfg));
    661 	REQUIRE(name != NULL);
    662 	REQUIRE(type == ISC_LOG_TOSYSLOG || type == ISC_LOG_TOFILE ||
    663 		type == ISC_LOG_TOFILEDESC || type == ISC_LOG_TONULL);
    664 	REQUIRE(destination != NULL || type == ISC_LOG_TONULL);
    665 	REQUIRE(level >= ISC_LOG_CRITICAL);
    666 	REQUIRE((flags & ~permitted) == 0);
    667 
    668 	/* XXXDCL find duplicate names? */
    669 
    670 	mctx = lcfg->lctx->mctx;
    671 
    672 	channel = isc_mem_get(mctx, sizeof(*channel));
    673 
    674 	channel->name = isc_mem_strdup(mctx, name);
    675 
    676 	channel->type = type;
    677 	channel->level = level;
    678 	channel->flags = flags;
    679 	ISC_LINK_INIT(channel, link);
    680 
    681 	switch (type) {
    682 	case ISC_LOG_TOSYSLOG:
    683 		FACILITY(channel) = destination->facility;
    684 		break;
    685 
    686 	case ISC_LOG_TOFILE:
    687 		/*
    688 		 * The file name is copied because greatest_version wants
    689 		 * to scribble on it, so it needs to be definitely in
    690 		 * writable memory.
    691 		 */
    692 		FILE_NAME(channel) = isc_mem_strdup(mctx,
    693 						    destination->file.name);
    694 		FILE_STREAM(channel) = NULL;
    695 		FILE_VERSIONS(channel) = destination->file.versions;
    696 		FILE_SUFFIX(channel) = destination->file.suffix;
    697 		FILE_MAXSIZE(channel) = destination->file.maximum_size;
    698 		FILE_MAXREACHED(channel) = false;
    699 		break;
    700 
    701 	case ISC_LOG_TOFILEDESC:
    702 		FILE_NAME(channel) = NULL;
    703 		FILE_STREAM(channel) = destination->file.stream;
    704 		FILE_MAXSIZE(channel) = 0;
    705 		FILE_VERSIONS(channel) = ISC_LOG_ROLLNEVER;
    706 		FILE_SUFFIX(channel) = isc_log_rollsuffix_increment;
    707 		break;
    708 
    709 	case ISC_LOG_TONULL:
    710 		/* Nothing. */
    711 		break;
    712 
    713 	default:
    714 		UNREACHABLE();
    715 	}
    716 
    717 	ISC_LIST_PREPEND(lcfg->channels, channel, link);
    718 
    719 	/*
    720 	 * If default_stderr was redefined, make the default category
    721 	 * point to the new default_stderr.
    722 	 */
    723 	if (strcmp(name, "default_stderr") == 0) {
    724 		default_channel.channel = channel;
    725 	}
    726 }
    727 
    728 isc_result_t
    729 isc_log_usechannel(isc_logconfig_t *lcfg, const char *name,
    730 		   const isc_logcategory_t *category,
    731 		   const isc_logmodule_t *module) {
    732 	isc_log_t *lctx;
    733 	isc_logchannel_t *channel;
    734 
    735 	REQUIRE(VALID_CONFIG(lcfg));
    736 	REQUIRE(name != NULL);
    737 
    738 	lctx = lcfg->lctx;
    739 
    740 	REQUIRE(category == NULL || category->id < lctx->category_count);
    741 	REQUIRE(module == NULL || module->id < lctx->module_count);
    742 
    743 	for (channel = ISC_LIST_HEAD(lcfg->channels); channel != NULL;
    744 	     channel = ISC_LIST_NEXT(channel, link))
    745 	{
    746 		if (strcmp(name, channel->name) == 0) {
    747 			break;
    748 		}
    749 	}
    750 
    751 	if (channel == NULL) {
    752 		return (ISC_R_NOTFOUND);
    753 	}
    754 
    755 	if (category != NULL) {
    756 		assignchannel(lcfg, category->id, module, channel);
    757 	} else {
    758 		/*
    759 		 * Assign to all categories.  Note that this includes
    760 		 * the default channel.
    761 		 */
    762 		for (size_t i = 0; i < lctx->category_count; i++) {
    763 			assignchannel(lcfg, i, module, channel);
    764 		}
    765 	}
    766 
    767 	/*
    768 	 * Update the highest logging level, if the current lcfg is in use.
    769 	 */
    770 	if (lcfg->lctx->logconfig == lcfg) {
    771 		sync_highest_level(lctx, lcfg);
    772 	}
    773 
    774 	return (ISC_R_SUCCESS);
    775 }
    776 
    777 void
    778 isc_log_write(isc_log_t *lctx, isc_logcategory_t *category,
    779 	      isc_logmodule_t *module, int level, const char *format, ...) {
    780 	va_list args;
    781 
    782 	/*
    783 	 * Contract checking is done in isc_log_doit().
    784 	 */
    785 
    786 	va_start(args, format);
    787 	isc_log_doit(lctx, category, module, level, false, format, args);
    788 	va_end(args);
    789 }
    790 
    791 void
    792 isc_log_vwrite(isc_log_t *lctx, isc_logcategory_t *category,
    793 	       isc_logmodule_t *module, int level, const char *format,
    794 	       va_list args) {
    795 	/*
    796 	 * Contract checking is done in isc_log_doit().
    797 	 */
    798 	isc_log_doit(lctx, category, module, level, false, format, args);
    799 }
    800 
    801 void
    802 isc_log_write1(isc_log_t *lctx, isc_logcategory_t *category,
    803 	       isc_logmodule_t *module, int level, const char *format, ...) {
    804 	va_list args;
    805 
    806 	/*
    807 	 * Contract checking is done in isc_log_doit().
    808 	 */
    809 
    810 	va_start(args, format);
    811 	isc_log_doit(lctx, category, module, level, true, format, args);
    812 	va_end(args);
    813 }
    814 
    815 void
    816 isc_log_vwrite1(isc_log_t *lctx, isc_logcategory_t *category,
    817 		isc_logmodule_t *module, int level, const char *format,
    818 		va_list args) {
    819 	/*
    820 	 * Contract checking is done in isc_log_doit().
    821 	 */
    822 	isc_log_doit(lctx, category, module, level, true, format, args);
    823 }
    824 
    825 void
    826 isc_log_setcontext(isc_log_t *lctx) {
    827 	isc_lctx = lctx;
    828 }
    829 
    830 void
    831 isc_log_setdebuglevel(isc_log_t *lctx, unsigned int level) {
    832 	REQUIRE(VALID_CONTEXT(lctx));
    833 
    834 	atomic_store_release(&lctx->debug_level, level);
    835 	/*
    836 	 * Close ISC_LOG_DEBUGONLY channels if level is zero.
    837 	 */
    838 	if (level == 0) {
    839 		RDLOCK(&lctx->lcfg_rwl);
    840 		isc_logconfig_t *lcfg = lctx->logconfig;
    841 		if (lcfg != NULL) {
    842 			LOCK(&lctx->lock);
    843 			for (isc_logchannel_t *channel =
    844 				     ISC_LIST_HEAD(lcfg->channels);
    845 			     channel != NULL;
    846 			     channel = ISC_LIST_NEXT(channel, link))
    847 			{
    848 				if (channel->type == ISC_LOG_TOFILE &&
    849 				    (channel->flags & ISC_LOG_DEBUGONLY) != 0 &&
    850 				    FILE_STREAM(channel) != NULL)
    851 				{
    852 					(void)fclose(FILE_STREAM(channel));
    853 					FILE_STREAM(channel) = NULL;
    854 				}
    855 			}
    856 			UNLOCK(&lctx->lock);
    857 		}
    858 		RDUNLOCK(&lctx->lcfg_rwl);
    859 	}
    860 }
    861 
    862 unsigned int
    863 isc_log_getdebuglevel(isc_log_t *lctx) {
    864 	REQUIRE(VALID_CONTEXT(lctx));
    865 
    866 	return (atomic_load_acquire(&lctx->debug_level));
    867 }
    868 
    869 void
    870 isc_log_setduplicateinterval(isc_logconfig_t *lcfg, unsigned int interval) {
    871 	REQUIRE(VALID_CONFIG(lcfg));
    872 
    873 	lcfg->duplicate_interval = interval;
    874 }
    875 
    876 unsigned int
    877 isc_log_getduplicateinterval(isc_logconfig_t *lcfg) {
    878 	REQUIRE(VALID_CONTEXT(lcfg));
    879 
    880 	return (lcfg->duplicate_interval);
    881 }
    882 
    883 void
    884 isc_log_settag(isc_logconfig_t *lcfg, const char *tag) {
    885 	REQUIRE(VALID_CONFIG(lcfg));
    886 
    887 	if (tag != NULL && *tag != '\0') {
    888 		if (lcfg->tag != NULL) {
    889 			isc_mem_free(lcfg->lctx->mctx, lcfg->tag);
    890 		}
    891 		lcfg->tag = isc_mem_strdup(lcfg->lctx->mctx, tag);
    892 	} else {
    893 		if (lcfg->tag != NULL) {
    894 			isc_mem_free(lcfg->lctx->mctx, lcfg->tag);
    895 		}
    896 		lcfg->tag = NULL;
    897 	}
    898 }
    899 
    900 char *
    901 isc_log_gettag(isc_logconfig_t *lcfg) {
    902 	REQUIRE(VALID_CONFIG(lcfg));
    903 
    904 	return (lcfg->tag);
    905 }
    906 
    907 /* XXXDCL NT  -- This interface will assuredly be changing. */
    908 void
    909 isc_log_opensyslog(const char *tag, int options, int facility) {
    910 	(void)openlog(tag, options, facility);
    911 }
    912 
    913 void
    914 isc_log_closefilelogs(isc_log_t *lctx) {
    915 	REQUIRE(VALID_CONTEXT(lctx));
    916 
    917 	RDLOCK(&lctx->lcfg_rwl);
    918 	isc_logconfig_t *lcfg = lctx->logconfig;
    919 	if (lcfg != NULL) {
    920 		LOCK(&lctx->lock);
    921 		for (isc_logchannel_t *channel = ISC_LIST_HEAD(lcfg->channels);
    922 		     channel != NULL; channel = ISC_LIST_NEXT(channel, link))
    923 		{
    924 			if (channel->type == ISC_LOG_TOFILE &&
    925 			    FILE_STREAM(channel) != NULL)
    926 			{
    927 				(void)fclose(FILE_STREAM(channel));
    928 				FILE_STREAM(channel) = NULL;
    929 			}
    930 		}
    931 		UNLOCK(&lctx->lock);
    932 	}
    933 	RDUNLOCK(&lctx->lcfg_rwl);
    934 }
    935 
    936 /****
    937 **** Internal functions
    938 ****/
    939 
    940 static void
    941 assignchannel(isc_logconfig_t *lcfg, unsigned int category_id,
    942 	      const isc_logmodule_t *module, isc_logchannel_t *channel) {
    943 	isc_logchannellist_t *new_item;
    944 	isc_log_t *lctx;
    945 
    946 	REQUIRE(VALID_CONFIG(lcfg));
    947 
    948 	lctx = lcfg->lctx;
    949 
    950 	REQUIRE(category_id < lctx->category_count);
    951 	REQUIRE(module == NULL || module->id < lctx->module_count);
    952 	REQUIRE(channel != NULL);
    953 
    954 	/*
    955 	 * Ensure lcfg->channellist_count == lctx->category_count.
    956 	 */
    957 	sync_channellist(lcfg);
    958 
    959 	new_item = isc_mem_get(lctx->mctx, sizeof(*new_item));
    960 
    961 	new_item->channel = channel;
    962 	new_item->module = module;
    963 	ISC_LIST_INITANDPREPEND(lcfg->channellists[category_id], new_item,
    964 				link);
    965 
    966 	/*
    967 	 * Remember the highest logging level set by any channel in the
    968 	 * logging config, so isc_log_doit() can quickly return if the
    969 	 * message is too high to be logged by any channel.
    970 	 */
    971 	if (channel->type != ISC_LOG_TONULL) {
    972 		if (lcfg->highest_level < channel->level) {
    973 			lcfg->highest_level = channel->level;
    974 		}
    975 		if (channel->level == ISC_LOG_DYNAMIC) {
    976 			lcfg->dynamic = true;
    977 		}
    978 	}
    979 }
    980 
    981 /*
    982  * This would ideally be part of isc_log_registercategories(), except then
    983  * that function would have to return isc_result_t instead of void.
    984  */
    985 static void
    986 sync_channellist(isc_logconfig_t *lcfg) {
    987 	unsigned int bytes;
    988 	isc_log_t *lctx;
    989 	void *lists;
    990 
    991 	REQUIRE(VALID_CONFIG(lcfg));
    992 
    993 	lctx = lcfg->lctx;
    994 
    995 	REQUIRE(lctx->category_count != 0);
    996 
    997 	if (lctx->category_count == lcfg->channellist_count) {
    998 		return;
    999 	}
   1000 
   1001 	bytes = lctx->category_count * sizeof(ISC_LIST(isc_logchannellist_t));
   1002 
   1003 	lists = isc_mem_get(lctx->mctx, bytes);
   1004 
   1005 	memset(lists, 0, bytes);
   1006 
   1007 	if (lcfg->channellist_count != 0) {
   1008 		bytes = lcfg->channellist_count *
   1009 			sizeof(ISC_LIST(isc_logchannellist_t));
   1010 		memmove(lists, lcfg->channellists, bytes);
   1011 		isc_mem_put(lctx->mctx, lcfg->channellists, bytes);
   1012 	}
   1013 
   1014 	lcfg->channellists = lists;
   1015 	lcfg->channellist_count = lctx->category_count;
   1016 }
   1017 
   1018 static void
   1019 sync_highest_level(isc_log_t *lctx, isc_logconfig_t *lcfg) {
   1020 	atomic_store(&lctx->highest_level, lcfg->highest_level);
   1021 	atomic_store(&lctx->dynamic, lcfg->dynamic);
   1022 }
   1023 
   1024 static isc_result_t
   1025 greatest_version(isc_logfile_t *file, int versions, int *greatestp) {
   1026 	char *digit_end;
   1027 	char dirbuf[PATH_MAX + 1];
   1028 	const char *bname;
   1029 	const char *dirname = ".";
   1030 	int version, greatest = -1;
   1031 	isc_dir_t dir;
   1032 	isc_result_t result;
   1033 	size_t bnamelen;
   1034 
   1035 	bname = strrchr(file->name, '/');
   1036 	if (bname != NULL) {
   1037 		/*
   1038 		 * Copy the complete file name to dirbuf.
   1039 		 */
   1040 		size_t len = strlcpy(dirbuf, file->name, sizeof(dirbuf));
   1041 		if (len >= sizeof(dirbuf)) {
   1042 			result = ISC_R_NOSPACE;
   1043 			syslog(LOG_ERR, "unable to remove log files: %s",
   1044 			       isc_result_totext(result));
   1045 			return (result);
   1046 		}
   1047 
   1048 		/*
   1049 		 * Truncate after trailing '/' so the code works for
   1050 		 * files in the root directory.
   1051 		 */
   1052 		bname++;
   1053 		dirbuf[bname - file->name] = '\0';
   1054 		dirname = dirbuf;
   1055 	} else {
   1056 		bname = file->name;
   1057 	}
   1058 	bnamelen = strlen(bname);
   1059 
   1060 	isc_dir_init(&dir);
   1061 	result = isc_dir_open(&dir, dirname);
   1062 
   1063 	/*
   1064 	 * Return if the directory open failed.
   1065 	 */
   1066 	if (result != ISC_R_SUCCESS) {
   1067 		return (result);
   1068 	}
   1069 
   1070 	while (isc_dir_read(&dir) == ISC_R_SUCCESS) {
   1071 		if (dir.entry.length > bnamelen &&
   1072 		    strncmp(dir.entry.name, bname, bnamelen) == 0 &&
   1073 		    dir.entry.name[bnamelen] == '.')
   1074 		{
   1075 			version = strtol(&dir.entry.name[bnamelen + 1],
   1076 					 &digit_end, 10);
   1077 			/*
   1078 			 * Remove any backup files that exceed versions.
   1079 			 */
   1080 			if (*digit_end == '\0' && version >= versions) {
   1081 				int n = unlinkat(dirfd(dir.handle),
   1082 						 dir.entry.name, 0);
   1083 				if (n < 0) {
   1084 					result = isc_errno_toresult(errno);
   1085 					if (result != ISC_R_SUCCESS &&
   1086 					    result != ISC_R_FILENOTFOUND)
   1087 					{
   1088 						syslog(LOG_ERR,
   1089 						       "unable to remove log "
   1090 						       "file '%s%s': %s",
   1091 						       bname == file->name
   1092 							       ? ""
   1093 							       : dirname,
   1094 						       dir.entry.name,
   1095 						       isc_result_totext(
   1096 							       result));
   1097 					}
   1098 				}
   1099 			} else if (*digit_end == '\0' && version > greatest) {
   1100 				greatest = version;
   1101 			}
   1102 		}
   1103 	}
   1104 	isc_dir_close(&dir);
   1105 
   1106 	*greatestp = greatest;
   1107 	return (ISC_R_SUCCESS);
   1108 }
   1109 
   1110 static void
   1111 insert_sort(int64_t to_keep[], int64_t versions, int64_t version) {
   1112 	int i = 0;
   1113 	while (i < versions && version < to_keep[i]) {
   1114 		i++;
   1115 	}
   1116 	if (i == versions) {
   1117 		return;
   1118 	}
   1119 	if (i < versions - 1) {
   1120 		memmove(&to_keep[i + 1], &to_keep[i],
   1121 			sizeof(to_keep[0]) * (versions - i - 1));
   1122 	}
   1123 	to_keep[i] = version;
   1124 }
   1125 
   1126 static int64_t
   1127 last_to_keep(int64_t versions, isc_dir_t *dirp, const char *bname,
   1128 	     size_t bnamelen) {
   1129 	int64_t to_keep[ISC_LOG_MAX_VERSIONS] = { 0 };
   1130 	int64_t version = 0;
   1131 
   1132 	if (versions <= 0) {
   1133 		return (INT64_MAX);
   1134 	}
   1135 
   1136 	if (versions > ISC_LOG_MAX_VERSIONS) {
   1137 		versions = ISC_LOG_MAX_VERSIONS;
   1138 	}
   1139 	/*
   1140 	 * First we fill 'to_keep' structure using insertion sort
   1141 	 */
   1142 	memset(to_keep, 0, sizeof(to_keep));
   1143 	while (isc_dir_read(dirp) == ISC_R_SUCCESS) {
   1144 		char *digit_end = NULL;
   1145 		char *ename = NULL;
   1146 
   1147 		if (dirp->entry.length <= bnamelen ||
   1148 		    strncmp(dirp->entry.name, bname, bnamelen) != 0 ||
   1149 		    dirp->entry.name[bnamelen] != '.')
   1150 		{
   1151 			continue;
   1152 		}
   1153 
   1154 		ename = &dirp->entry.name[bnamelen + 1];
   1155 		version = strtoull(ename, &digit_end, 10);
   1156 		if (*digit_end == '\0') {
   1157 			insert_sort(to_keep, versions, version);
   1158 		}
   1159 	}
   1160 
   1161 	isc_dir_reset(dirp);
   1162 
   1163 	/*
   1164 	 * to_keep[versions - 1] is the last one we want to keep
   1165 	 */
   1166 	return (to_keep[versions - 1]);
   1167 }
   1168 
   1169 static isc_result_t
   1170 remove_old_tsversions(isc_logfile_t *file, int versions) {
   1171 	char *digit_end;
   1172 	char dirbuf[PATH_MAX + 1];
   1173 	const char *bname;
   1174 	const char *dirname = ".";
   1175 	int64_t version, last = INT64_MAX;
   1176 	isc_dir_t dir;
   1177 	isc_result_t result;
   1178 	size_t bnamelen;
   1179 
   1180 	bname = strrchr(file->name, '/');
   1181 	if (bname != NULL) {
   1182 		/*
   1183 		 * Copy the complete file name to dirbuf.
   1184 		 */
   1185 		size_t len = strlcpy(dirbuf, file->name, sizeof(dirbuf));
   1186 		if (len >= sizeof(dirbuf)) {
   1187 			result = ISC_R_NOSPACE;
   1188 			syslog(LOG_ERR, "unable to remove log files: %s",
   1189 			       isc_result_totext(result));
   1190 			return (result);
   1191 		}
   1192 
   1193 		/*
   1194 		 * Truncate after trailing '/' so the code works for
   1195 		 * files in the root directory.
   1196 		 */
   1197 		bname++;
   1198 		dirbuf[bname - file->name] = '\0';
   1199 		dirname = dirbuf;
   1200 	} else {
   1201 		bname = file->name;
   1202 	}
   1203 	bnamelen = strlen(bname);
   1204 
   1205 	isc_dir_init(&dir);
   1206 	result = isc_dir_open(&dir, dirname);
   1207 
   1208 	/*
   1209 	 * Return if the directory open failed.
   1210 	 */
   1211 	if (result != ISC_R_SUCCESS) {
   1212 		return (result);
   1213 	}
   1214 
   1215 	last = last_to_keep(versions, &dir, bname, bnamelen);
   1216 
   1217 	while (isc_dir_read(&dir) == ISC_R_SUCCESS) {
   1218 		if (dir.entry.length > bnamelen &&
   1219 		    strncmp(dir.entry.name, bname, bnamelen) == 0 &&
   1220 		    dir.entry.name[bnamelen] == '.')
   1221 		{
   1222 			version = strtoull(&dir.entry.name[bnamelen + 1],
   1223 					   &digit_end, 10);
   1224 			/*
   1225 			 * Remove any backup files that exceed versions.
   1226 			 */
   1227 			if (*digit_end == '\0' && version < last) {
   1228 				int n = unlinkat(dirfd(dir.handle),
   1229 						 dir.entry.name, 0);
   1230 				if (n < 0) {
   1231 					result = isc_errno_toresult(errno);
   1232 					if (result != ISC_R_SUCCESS &&
   1233 					    result != ISC_R_FILENOTFOUND)
   1234 					{
   1235 						syslog(LOG_ERR,
   1236 						       "unable to remove log "
   1237 						       "file '%s%s': %s",
   1238 						       bname == file->name
   1239 							       ? ""
   1240 							       : dirname,
   1241 						       dir.entry.name,
   1242 						       isc_result_totext(
   1243 							       result));
   1244 					}
   1245 				}
   1246 			}
   1247 		}
   1248 	}
   1249 	isc_dir_close(&dir);
   1250 	return (ISC_R_SUCCESS);
   1251 }
   1252 
   1253 static isc_result_t
   1254 roll_increment(isc_logfile_t *file) {
   1255 	int i, n, greatest;
   1256 	char current[PATH_MAX + 1];
   1257 	char newpath[PATH_MAX + 1];
   1258 	const char *path;
   1259 	isc_result_t result = ISC_R_SUCCESS;
   1260 
   1261 	REQUIRE(file != NULL);
   1262 	REQUIRE(file->versions != 0);
   1263 
   1264 	path = file->name;
   1265 
   1266 	if (file->versions == ISC_LOG_ROLLINFINITE) {
   1267 		/*
   1268 		 * Find the first missing entry in the log file sequence.
   1269 		 */
   1270 		for (greatest = 0; greatest < INT_MAX; greatest++) {
   1271 			n = snprintf(current, sizeof(current), "%s.%u", path,
   1272 				     (unsigned)greatest);
   1273 			if (n >= (int)sizeof(current) || n < 0 ||
   1274 			    !isc_file_exists(current))
   1275 			{
   1276 				break;
   1277 			}
   1278 		}
   1279 	} else {
   1280 		/*
   1281 		 * Get the largest existing version and remove any
   1282 		 * version greater than the permitted version.
   1283 		 */
   1284 		result = greatest_version(file, file->versions, &greatest);
   1285 		if (result != ISC_R_SUCCESS) {
   1286 			return (result);
   1287 		}
   1288 
   1289 		/*
   1290 		 * Increment if greatest is not the actual maximum value.
   1291 		 */
   1292 		if (greatest < file->versions - 1) {
   1293 			greatest++;
   1294 		}
   1295 	}
   1296 
   1297 	for (i = greatest; i > 0; i--) {
   1298 		result = ISC_R_SUCCESS;
   1299 		n = snprintf(current, sizeof(current), "%s.%u", path,
   1300 			     (unsigned)(i - 1));
   1301 		if (n >= (int)sizeof(current) || n < 0) {
   1302 			result = ISC_R_NOSPACE;
   1303 		}
   1304 		if (result == ISC_R_SUCCESS) {
   1305 			n = snprintf(newpath, sizeof(newpath), "%s.%u", path,
   1306 				     (unsigned)i);
   1307 			if (n >= (int)sizeof(newpath) || n < 0) {
   1308 				result = ISC_R_NOSPACE;
   1309 			}
   1310 		}
   1311 		if (result == ISC_R_SUCCESS) {
   1312 			result = isc_file_rename(current, newpath);
   1313 		}
   1314 		if (result != ISC_R_SUCCESS && result != ISC_R_FILENOTFOUND) {
   1315 			syslog(LOG_ERR,
   1316 			       "unable to rename log file '%s.%u' to "
   1317 			       "'%s.%u': %s",
   1318 			       path, i - 1, path, i, isc_result_totext(result));
   1319 		}
   1320 	}
   1321 
   1322 	n = snprintf(newpath, sizeof(newpath), "%s.0", path);
   1323 	if (n >= (int)sizeof(newpath) || n < 0) {
   1324 		result = ISC_R_NOSPACE;
   1325 	} else {
   1326 		result = isc_file_rename(path, newpath);
   1327 	}
   1328 	if (result != ISC_R_SUCCESS && result != ISC_R_FILENOTFOUND) {
   1329 		syslog(LOG_ERR, "unable to rename log file '%s' to '%s.0': %s",
   1330 		       path, path, isc_result_totext(result));
   1331 	}
   1332 
   1333 	return (ISC_R_SUCCESS);
   1334 }
   1335 
   1336 static isc_result_t
   1337 roll_timestamp(isc_logfile_t *file) {
   1338 	int n;
   1339 	char newts[PATH_MAX + 1];
   1340 	char newpath[PATH_MAX + 1];
   1341 	const char *path;
   1342 	isc_time_t now;
   1343 	isc_result_t result = ISC_R_SUCCESS;
   1344 
   1345 	REQUIRE(file != NULL);
   1346 	REQUIRE(file->versions != 0);
   1347 
   1348 	path = file->name;
   1349 
   1350 	/*
   1351 	 * First find all the logfiles and remove the oldest ones
   1352 	 * Save one fewer than file->versions because we'll be renaming
   1353 	 * the existing file to a timestamped version after this.
   1354 	 */
   1355 	if (file->versions != ISC_LOG_ROLLINFINITE) {
   1356 		remove_old_tsversions(file, file->versions - 1);
   1357 	}
   1358 
   1359 	/* Then just rename the current logfile */
   1360 	isc_time_now(&now);
   1361 	isc_time_formatshorttimestamp(&now, newts, PATH_MAX + 1);
   1362 	n = snprintf(newpath, sizeof(newpath), "%s.%s", path, newts);
   1363 	if (n >= (int)sizeof(newpath) || n < 0) {
   1364 		result = ISC_R_NOSPACE;
   1365 	} else {
   1366 		result = isc_file_rename(path, newpath);
   1367 	}
   1368 	if (result != ISC_R_SUCCESS && result != ISC_R_FILENOTFOUND) {
   1369 		syslog(LOG_ERR, "unable to rename log file '%s' to '%s.0': %s",
   1370 		       path, path, isc_result_totext(result));
   1371 	}
   1372 
   1373 	return (ISC_R_SUCCESS);
   1374 }
   1375 
   1376 isc_result_t
   1377 isc_logfile_roll(isc_logfile_t *file) {
   1378 	isc_result_t result;
   1379 
   1380 	REQUIRE(file != NULL);
   1381 
   1382 	/*
   1383 	 * Do nothing (not even excess version trimming) if ISC_LOG_ROLLNEVER
   1384 	 * is specified.  Apparently complete external control over the log
   1385 	 * files is desired.
   1386 	 */
   1387 	if (file->versions == ISC_LOG_ROLLNEVER) {
   1388 		return (ISC_R_SUCCESS);
   1389 	} else if (file->versions == 0) {
   1390 		result = isc_file_remove(file->name);
   1391 		if (result != ISC_R_SUCCESS && result != ISC_R_FILENOTFOUND) {
   1392 			syslog(LOG_ERR, "unable to remove log file '%s': %s",
   1393 			       file->name, isc_result_totext(result));
   1394 		}
   1395 		return (ISC_R_SUCCESS);
   1396 	}
   1397 
   1398 	switch (file->suffix) {
   1399 	case isc_log_rollsuffix_increment:
   1400 		return (roll_increment(file));
   1401 	case isc_log_rollsuffix_timestamp:
   1402 		return (roll_timestamp(file));
   1403 	default:
   1404 		return (ISC_R_UNEXPECTED);
   1405 	}
   1406 }
   1407 
   1408 static isc_result_t
   1409 isc_log_open(isc_logchannel_t *channel) {
   1410 	struct stat statbuf;
   1411 	bool regular_file;
   1412 	bool roll = false;
   1413 	isc_result_t result = ISC_R_SUCCESS;
   1414 	const char *path;
   1415 
   1416 	REQUIRE(channel->type == ISC_LOG_TOFILE);
   1417 	REQUIRE(FILE_STREAM(channel) == NULL);
   1418 
   1419 	path = FILE_NAME(channel);
   1420 
   1421 	REQUIRE(path != NULL && *path != '\0');
   1422 
   1423 	/*
   1424 	 * Determine type of file; only regular files will be
   1425 	 * version renamed, and only if the base file exists
   1426 	 * and either has no size limit or has reached its size limit.
   1427 	 */
   1428 	if (stat(path, &statbuf) == 0) {
   1429 		regular_file = S_ISREG(statbuf.st_mode) ? true : false;
   1430 		/* XXXDCL if not regular_file complain? */
   1431 		if ((FILE_MAXSIZE(channel) == 0 &&
   1432 		     FILE_VERSIONS(channel) != ISC_LOG_ROLLNEVER) ||
   1433 		    (FILE_MAXSIZE(channel) > 0 &&
   1434 		     statbuf.st_size >= FILE_MAXSIZE(channel)))
   1435 		{
   1436 			roll = regular_file;
   1437 		}
   1438 	} else if (errno == ENOENT) {
   1439 		regular_file = true;
   1440 		POST(regular_file);
   1441 	} else {
   1442 		result = ISC_R_INVALIDFILE;
   1443 	}
   1444 
   1445 	/*
   1446 	 * Version control.
   1447 	 */
   1448 	if (result == ISC_R_SUCCESS && roll) {
   1449 		if (FILE_VERSIONS(channel) == ISC_LOG_ROLLNEVER) {
   1450 			return (ISC_R_MAXSIZE);
   1451 		}
   1452 		result = isc_logfile_roll(&channel->destination.file);
   1453 		if (result != ISC_R_SUCCESS) {
   1454 			if ((channel->flags & ISC_LOG_OPENERR) == 0) {
   1455 				syslog(LOG_ERR,
   1456 				       "isc_log_open: isc_logfile_roll '%s' "
   1457 				       "failed: %s",
   1458 				       FILE_NAME(channel),
   1459 				       isc_result_totext(result));
   1460 				channel->flags |= ISC_LOG_OPENERR;
   1461 			}
   1462 			return (result);
   1463 		}
   1464 	}
   1465 
   1466 	result = isc_stdio_open(path, "a", &FILE_STREAM(channel));
   1467 
   1468 	return (result);
   1469 }
   1470 
   1471 ISC_NO_SANITIZE_THREAD bool
   1472 isc_log_wouldlog(isc_log_t *lctx, int level) {
   1473 	/*
   1474 	 * Try to avoid locking the mutex for messages which can't
   1475 	 * possibly be logged to any channels -- primarily debugging
   1476 	 * messages that the debug level is not high enough to print.
   1477 	 *
   1478 	 * If the level is (mathematically) less than or equal to the
   1479 	 * highest_level, or if there is a dynamic channel and the level is
   1480 	 * less than or equal to the debug level, the main loop must be
   1481 	 * entered to see if the message should really be output.
   1482 	 */
   1483 	if (lctx == NULL) {
   1484 		return (false);
   1485 	}
   1486 	if (forcelog) {
   1487 		return (true);
   1488 	}
   1489 
   1490 	int highest_level = atomic_load_acquire(&lctx->highest_level);
   1491 	if (level <= highest_level) {
   1492 		return (true);
   1493 	}
   1494 	if (atomic_load_acquire(&lctx->dynamic)) {
   1495 		int debug_level = atomic_load_acquire(&lctx->debug_level);
   1496 		if (level <= debug_level) {
   1497 			return (true);
   1498 		}
   1499 	}
   1500 
   1501 	return (false);
   1502 }
   1503 
   1504 static void
   1505 isc_log_doit(isc_log_t *lctx, isc_logcategory_t *category,
   1506 	     isc_logmodule_t *module, int level, bool write_once,
   1507 	     const char *format, va_list args) {
   1508 	int syslog_level;
   1509 	const char *time_string;
   1510 	char local_time[64];
   1511 	char iso8601z_string[64];
   1512 	char iso8601l_string[64];
   1513 	char level_string[24] = { 0 };
   1514 	struct stat statbuf;
   1515 	bool matched = false;
   1516 	bool printtime, iso8601, utc, printtag, printcolon;
   1517 	bool printcategory, printmodule, printlevel, buffered;
   1518 	isc_logchannel_t *channel;
   1519 	isc_logchannellist_t *category_channels;
   1520 	int_fast32_t dlevel;
   1521 	isc_result_t result;
   1522 
   1523 	REQUIRE(lctx == NULL || VALID_CONTEXT(lctx));
   1524 	REQUIRE(category != NULL);
   1525 	REQUIRE(module != NULL);
   1526 	REQUIRE(level != ISC_LOG_DYNAMIC);
   1527 	REQUIRE(format != NULL);
   1528 
   1529 	/*
   1530 	 * Programs can use libraries that use this logging code without
   1531 	 * wanting to do any logging, thus the log context is allowed to
   1532 	 * be non-existent.
   1533 	 */
   1534 	if (lctx == NULL) {
   1535 		return;
   1536 	}
   1537 
   1538 	REQUIRE(category->id < lctx->category_count);
   1539 	REQUIRE(module->id < lctx->module_count);
   1540 
   1541 	if (!isc_log_wouldlog(lctx, level)) {
   1542 		return;
   1543 	}
   1544 
   1545 	local_time[0] = '\0';
   1546 	iso8601l_string[0] = '\0';
   1547 	iso8601z_string[0] = '\0';
   1548 
   1549 	RDLOCK(&lctx->lcfg_rwl);
   1550 	LOCK(&lctx->lock);
   1551 
   1552 	lctx->buffer[0] = '\0';
   1553 
   1554 	isc_logconfig_t *lcfg = lctx->logconfig;
   1555 
   1556 	category_channels = ISC_LIST_HEAD(lcfg->channellists[category->id]);
   1557 
   1558 	/*
   1559 	 * XXXDCL add duplicate filtering? (To not write multiple times
   1560 	 * to the same source via various channels).
   1561 	 */
   1562 	do {
   1563 		/*
   1564 		 * If the channel list end was reached and a match was
   1565 		 * made, everything is finished.
   1566 		 */
   1567 		if (category_channels == NULL && matched) {
   1568 			break;
   1569 		}
   1570 
   1571 		if (category_channels == NULL && !matched &&
   1572 		    category_channels != ISC_LIST_HEAD(lcfg->channellists[0]))
   1573 		{
   1574 			/*
   1575 			 * No category/module pair was explicitly
   1576 			 * configured. Try the category named "default".
   1577 			 */
   1578 			category_channels =
   1579 				ISC_LIST_HEAD(lcfg->channellists[0]);
   1580 		}
   1581 
   1582 		if (category_channels == NULL && !matched) {
   1583 			/*
   1584 			 * No matching module was explicitly configured
   1585 			 * for the category named "default".  Use the
   1586 			 * internal default channel.
   1587 			 */
   1588 			category_channels = &default_channel;
   1589 		}
   1590 
   1591 		if (category_channels->module != NULL &&
   1592 		    category_channels->module != module)
   1593 		{
   1594 			category_channels = ISC_LIST_NEXT(category_channels,
   1595 							  link);
   1596 			continue;
   1597 		}
   1598 
   1599 		matched = true;
   1600 
   1601 		channel = category_channels->channel;
   1602 		category_channels = ISC_LIST_NEXT(category_channels, link);
   1603 
   1604 		if (!forcelog) {
   1605 			dlevel = atomic_load_acquire(&lctx->debug_level);
   1606 			if (((channel->flags & ISC_LOG_DEBUGONLY) != 0) &&
   1607 			    dlevel == 0)
   1608 			{
   1609 				continue;
   1610 			}
   1611 
   1612 			if (channel->level == ISC_LOG_DYNAMIC) {
   1613 				if (dlevel < level) {
   1614 					continue;
   1615 				}
   1616 			} else if (channel->level < level) {
   1617 				continue;
   1618 			}
   1619 		}
   1620 
   1621 		if ((channel->flags & ISC_LOG_PRINTTIME) != 0 &&
   1622 		    local_time[0] == '\0')
   1623 		{
   1624 			isc_time_t isctime;
   1625 
   1626 			TIME_NOW(&isctime);
   1627 
   1628 			isc_time_formattimestamp(&isctime, local_time,
   1629 						 sizeof(local_time));
   1630 			isc_time_formatISO8601ms(&isctime, iso8601z_string,
   1631 						 sizeof(iso8601z_string));
   1632 			isc_time_formatISO8601Lms(&isctime, iso8601l_string,
   1633 						  sizeof(iso8601l_string));
   1634 		}
   1635 
   1636 		if ((channel->flags & ISC_LOG_PRINTLEVEL) != 0 &&
   1637 		    level_string[0] == '\0')
   1638 		{
   1639 			if (level < ISC_LOG_CRITICAL) {
   1640 				snprintf(level_string, sizeof(level_string),
   1641 					 "level %d: ", level);
   1642 			} else if (level > ISC_LOG_DYNAMIC) {
   1643 				snprintf(level_string, sizeof(level_string),
   1644 					 "%s %d: ", log_level_strings[0],
   1645 					 level);
   1646 			} else {
   1647 				snprintf(level_string, sizeof(level_string),
   1648 					 "%s: ", log_level_strings[-level]);
   1649 			}
   1650 		}
   1651 
   1652 		/*
   1653 		 * Only format the message once.
   1654 		 */
   1655 		if (lctx->buffer[0] == '\0') {
   1656 			(void)vsnprintf(lctx->buffer, sizeof(lctx->buffer),
   1657 					format, args);
   1658 
   1659 			/*
   1660 			 * Check for duplicates.
   1661 			 */
   1662 			if (write_once) {
   1663 				isc_logmessage_t *message, *next;
   1664 				isc_time_t oldest;
   1665 				isc_interval_t interval;
   1666 				size_t size;
   1667 
   1668 				isc_interval_set(&interval,
   1669 						 lcfg->duplicate_interval, 0);
   1670 
   1671 				/*
   1672 				 * 'oldest' is the age of the oldest
   1673 				 * messages which fall within the
   1674 				 * duplicate_interval range.
   1675 				 */
   1676 				TIME_NOW(&oldest);
   1677 				if (isc_time_subtract(&oldest, &interval,
   1678 						      &oldest) != ISC_R_SUCCESS)
   1679 				{
   1680 					/*
   1681 					 * Can't effectively do the
   1682 					 * checking without having a
   1683 					 * valid time.
   1684 					 */
   1685 					message = NULL;
   1686 				} else {
   1687 					message = ISC_LIST_HEAD(lctx->messages);
   1688 				}
   1689 
   1690 				while (message != NULL) {
   1691 					if (isc_time_compare(&message->time,
   1692 							     &oldest) < 0)
   1693 					{
   1694 						/*
   1695 						 * This message is older
   1696 						 * than the
   1697 						 * duplicate_interval,
   1698 						 * so it should be
   1699 						 * dropped from the
   1700 						 * history.
   1701 						 *
   1702 						 * Setting the interval
   1703 						 * to be to be longer
   1704 						 * will obviously not
   1705 						 * cause the expired
   1706 						 * message to spring
   1707 						 * back into existence.
   1708 						 */
   1709 						next = ISC_LIST_NEXT(message,
   1710 								     link);
   1711 
   1712 						ISC_LIST_UNLINK(lctx->messages,
   1713 								message, link);
   1714 
   1715 						isc_mem_put(
   1716 							lctx->mctx, message,
   1717 							sizeof(*message) + 1 +
   1718 								strlen(message->text));
   1719 
   1720 						message = next;
   1721 						continue;
   1722 					}
   1723 
   1724 					/*
   1725 					 * This message is in the
   1726 					 * duplicate filtering interval
   1727 					 * ...
   1728 					 */
   1729 					if (strcmp(lctx->buffer,
   1730 						   message->text) == 0)
   1731 					{
   1732 						/*
   1733 						 * ... and it is a
   1734 						 * duplicate. Unlock the
   1735 						 * mutex and get the
   1736 						 * hell out of Dodge.
   1737 						 */
   1738 						goto unlock;
   1739 					}
   1740 
   1741 					message = ISC_LIST_NEXT(message, link);
   1742 				}
   1743 
   1744 				/*
   1745 				 * It wasn't in the duplicate interval,
   1746 				 * so add it to the message list.
   1747 				 */
   1748 				size = sizeof(isc_logmessage_t) +
   1749 				       strlen(lctx->buffer) + 1;
   1750 				message = isc_mem_get(lctx->mctx, size);
   1751 				message->text = (char *)(message + 1);
   1752 				size -= sizeof(isc_logmessage_t);
   1753 				strlcpy(message->text, lctx->buffer, size);
   1754 				TIME_NOW(&message->time);
   1755 				ISC_LINK_INIT(message, link);
   1756 				ISC_LIST_APPEND(lctx->messages, message, link);
   1757 			}
   1758 		}
   1759 
   1760 		utc = ((channel->flags & ISC_LOG_UTC) != 0);
   1761 		iso8601 = ((channel->flags & ISC_LOG_ISO8601) != 0);
   1762 		printtime = ((channel->flags & ISC_LOG_PRINTTIME) != 0);
   1763 		printtag = ((channel->flags &
   1764 			     (ISC_LOG_PRINTTAG | ISC_LOG_PRINTPREFIX)) != 0 &&
   1765 			    lcfg->tag != NULL);
   1766 		printcolon = ((channel->flags & ISC_LOG_PRINTTAG) != 0 &&
   1767 			      lcfg->tag != NULL);
   1768 		printcategory = ((channel->flags & ISC_LOG_PRINTCATEGORY) != 0);
   1769 		printmodule = ((channel->flags & ISC_LOG_PRINTMODULE) != 0);
   1770 		printlevel = ((channel->flags & ISC_LOG_PRINTLEVEL) != 0);
   1771 		buffered = ((channel->flags & ISC_LOG_BUFFERED) != 0);
   1772 
   1773 		if (printtime) {
   1774 			if (iso8601) {
   1775 				if (utc) {
   1776 					time_string = iso8601z_string;
   1777 				} else {
   1778 					time_string = iso8601l_string;
   1779 				}
   1780 			} else {
   1781 				time_string = local_time;
   1782 			}
   1783 		} else {
   1784 			time_string = "";
   1785 		}
   1786 
   1787 		switch (channel->type) {
   1788 		case ISC_LOG_TOFILE:
   1789 			if (FILE_MAXREACHED(channel)) {
   1790 				/*
   1791 				 * If the file can be rolled, OR
   1792 				 * If the file no longer exists, OR
   1793 				 * If the file is less than the maximum
   1794 				 * size, (such as if it had been renamed
   1795 				 * and a new one touched, or it was
   1796 				 * truncated in place)
   1797 				 * ... then close it to trigger
   1798 				 * reopening.
   1799 				 */
   1800 				if (FILE_VERSIONS(channel) !=
   1801 					    ISC_LOG_ROLLNEVER ||
   1802 				    (stat(FILE_NAME(channel), &statbuf) != 0 &&
   1803 				     errno == ENOENT) ||
   1804 				    statbuf.st_size < FILE_MAXSIZE(channel))
   1805 				{
   1806 					(void)fclose(FILE_STREAM(channel));
   1807 					FILE_STREAM(channel) = NULL;
   1808 					FILE_MAXREACHED(channel) = false;
   1809 				} else {
   1810 					/*
   1811 					 * Eh, skip it.
   1812 					 */
   1813 					break;
   1814 				}
   1815 			}
   1816 
   1817 			if (FILE_STREAM(channel) == NULL) {
   1818 				result = isc_log_open(channel);
   1819 				if (result != ISC_R_SUCCESS &&
   1820 				    result != ISC_R_MAXSIZE &&
   1821 				    (channel->flags & ISC_LOG_OPENERR) == 0)
   1822 				{
   1823 					syslog(LOG_ERR,
   1824 					       "isc_log_open '%s' "
   1825 					       "failed: %s",
   1826 					       FILE_NAME(channel),
   1827 					       isc_result_totext(result));
   1828 					channel->flags |= ISC_LOG_OPENERR;
   1829 				}
   1830 				if (result != ISC_R_SUCCESS) {
   1831 					break;
   1832 				}
   1833 				channel->flags &= ~ISC_LOG_OPENERR;
   1834 			}
   1835 			FALLTHROUGH;
   1836 
   1837 		case ISC_LOG_TOFILEDESC:
   1838 			fprintf(FILE_STREAM(channel), "%s%s%s%s%s%s%s%s%s%s\n",
   1839 				printtime ? time_string : "",
   1840 				printtime ? " " : "", printtag ? lcfg->tag : "",
   1841 				printcolon ? ": " : "",
   1842 				printcategory ? category->name : "",
   1843 				printcategory ? ": " : "",
   1844 				printmodule ? (module != NULL ? module->name
   1845 							      : "no_module")
   1846 					    : "",
   1847 				printmodule ? ": " : "",
   1848 				printlevel ? level_string : "", lctx->buffer);
   1849 
   1850 			if (!buffered) {
   1851 				fflush(FILE_STREAM(channel));
   1852 			}
   1853 
   1854 			/*
   1855 			 * If the file now exceeds its maximum size
   1856 			 * threshold, note it so that it will not be
   1857 			 * logged to any more.
   1858 			 */
   1859 			if (FILE_MAXSIZE(channel) > 0) {
   1860 				INSIST(channel->type == ISC_LOG_TOFILE);
   1861 
   1862 				/* XXXDCL NT fstat/fileno */
   1863 				/* XXXDCL complain if fstat fails? */
   1864 				if (fstat(fileno(FILE_STREAM(channel)),
   1865 					  &statbuf) >= 0 &&
   1866 				    statbuf.st_size > FILE_MAXSIZE(channel))
   1867 				{
   1868 					FILE_MAXREACHED(channel) = true;
   1869 				}
   1870 			}
   1871 
   1872 			break;
   1873 
   1874 		case ISC_LOG_TOSYSLOG:
   1875 			if (level > 0) {
   1876 				syslog_level = LOG_DEBUG;
   1877 			} else if (level < ISC_LOG_CRITICAL) {
   1878 				syslog_level = LOG_CRIT;
   1879 			} else {
   1880 				syslog_level = syslog_map[-level];
   1881 			}
   1882 
   1883 			(void)syslog(
   1884 				FACILITY(channel) | syslog_level,
   1885 				"%s%s%s%s%s%s%s%s%s%s",
   1886 				printtime ? time_string : "",
   1887 				printtime ? " " : "", printtag ? lcfg->tag : "",
   1888 				printcolon ? ": " : "",
   1889 				printcategory ? category->name : "",
   1890 				printcategory ? ": " : "",
   1891 				printmodule ? (module != NULL ? module->name
   1892 							      : "no_module")
   1893 					    : "",
   1894 				printmodule ? ": " : "",
   1895 				printlevel ? level_string : "", lctx->buffer);
   1896 			break;
   1897 
   1898 		case ISC_LOG_TONULL:
   1899 			break;
   1900 		}
   1901 	} while (1);
   1902 
   1903 unlock:
   1904 	UNLOCK(&lctx->lock);
   1905 	RDUNLOCK(&lctx->lcfg_rwl);
   1906 }
   1907 
   1908 void
   1909 isc_log_setforcelog(bool v) {
   1910 	forcelog = v;
   1911 }
   1912