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/*
* Copyright (C) Internet Systems Consortium, Inc. ("ISC")
*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, you can obtain one at https://mozilla.org/MPL/2.0/.
*
* See the COPYRIGHT file distributed with this work for additional
* information regarding copyright ownership.
*/
#ifndef ISC_LOG_H
#define ISC_LOG_H 1
/*! \file isc/log.h */
#include <stdbool.h>
#include <stdio.h>
#include <stdarg.h>
#include <syslog.h> /* XXXDCL NT */
#include <isc/formatcheck.h>
#include <isc/lang.h>
#include <isc/platform.h>
#include <isc/types.h>
/*@{*/
/*!
* \brief Severity levels, patterned after Unix's syslog levels.
*
*/
#define ISC_LOG_DEBUG(level) (level)
/*!
* #ISC_LOG_DYNAMIC can only be used for defining channels with
* isc_log_createchannel(), not to specify a level in isc_log_write().
*/
#define ISC_LOG_DYNAMIC 0
#define ISC_LOG_INFO (-1)
#define ISC_LOG_NOTICE (-2)
#define ISC_LOG_WARNING (-3)
#define ISC_LOG_ERROR (-4)
#define ISC_LOG_CRITICAL (-5)
/*@}*/
/*@{*/
/*!
* \brief Destinations.
*/
#define ISC_LOG_TONULL 1
#define ISC_LOG_TOSYSLOG 2
#define ISC_LOG_TOFILE 3
#define ISC_LOG_TOFILEDESC 4
/*@}*/
/*@{*/
/*%
* Channel flags.
*/
#define ISC_LOG_PRINTTIME 0x0001
#define ISC_LOG_PRINTLEVEL 0x0002
#define ISC_LOG_PRINTCATEGORY 0x0004
#define ISC_LOG_PRINTMODULE 0x0008
#define ISC_LOG_PRINTTAG 0x0010 /* tag and ":" */
#define ISC_LOG_PRINTPREFIX 0x0020 /* tag only, no colon */
#define ISC_LOG_PRINTALL 0x003F
#define ISC_LOG_BUFFERED 0x0040
#define ISC_LOG_DEBUGONLY 0x1000
#define ISC_LOG_OPENERR 0x8000 /* internal */
/*@}*/
/*@{*/
/*!
* \brief Other options.
*
* XXXDCL INFINITE doesn't yet work. Arguably it isn't needed, but
* since I am intend to make large number of versions work efficiently,
* INFINITE is going to be trivial to add to that.
*/
#define ISC_LOG_ROLLINFINITE (-1)
#define ISC_LOG_ROLLNEVER (-2)
/*@}*/
/*!
* \brief Used to name the categories used by a library.
*
* An array of isc_logcategory
* structures names each category, and the id value is initialized by calling
* isc_log_registercategories.
*/
struct isc_logcategory {
const char *name;
unsigned int id;
};
/*%
* Similar to isc_logcategory, but for all the modules a library defines.
*/
struct isc_logmodule {
const char *name;
unsigned int id;
};
/*%
* The isc_logfile structure is initialized as part of an isc_logdestination
* before calling isc_log_createchannel().
*
* When defining an #ISC_LOG_TOFILE
* channel the name, versions and maximum_size should be set before calling
* isc_log_createchannel(). To define an #ISC_LOG_TOFILEDESC channel set only
* the stream before the call.
*
* Setting maximum_size to zero implies no maximum.
*/
typedef struct isc_logfile {
FILE *stream; /*%< Initialized to NULL for #ISC_LOG_TOFILE. */
const char *name; /*%< NULL for #ISC_LOG_TOFILEDESC. */
int versions; /* >= 0, #ISC_LOG_ROLLNEVER, #ISC_LOG_ROLLINFINITE. */
/*%
* stdio's ftell is standardized to return a long, which may well not
* be big enough for the largest file supportable by the operating
* system (though it is _probably_ big enough for the largest log
* anyone would want). st_size returned by fstat should be typedef'd
* to a size large enough for the largest possible file on a system.
*/
isc_offset_t maximum_size;
bool maximum_reached; /*%< Private. */
} isc_logfile_t;
/*%
* Passed to isc_log_createchannel to define the attributes of either
* a stdio or a syslog log.
*/
typedef union isc_logdestination {
isc_logfile_t file;
int facility; /* XXXDCL NT */
} isc_logdestination_t;
/*@{*/
/*%
* The built-in categories of libisc.
*
* Each library registering categories should provide library_LOGCATEGORY_name
* definitions with indexes into its isc_logcategory structure corresponding to
* the order of the names.
*/
LIBISC_EXTERNAL_DATA extern isc_logcategory_t isc_categories[];
LIBISC_EXTERNAL_DATA extern isc_log_t *isc_lctx;
LIBISC_EXTERNAL_DATA extern isc_logmodule_t isc_modules[];
/*@}*/
/*@{*/
/*%
* Do not log directly to DEFAULT. Use another category. When in doubt,
* use GENERAL.
*/
#define ISC_LOGCATEGORY_DEFAULT (&isc_categories[0])
#define ISC_LOGCATEGORY_GENERAL (&isc_categories[1])
/*@}*/
#define ISC_LOGMODULE_SOCKET (&isc_modules[0])
#define ISC_LOGMODULE_TIME (&isc_modules[1])
#define ISC_LOGMODULE_INTERFACE (&isc_modules[2])
#define ISC_LOGMODULE_TIMER (&isc_modules[3])
#define ISC_LOGMODULE_FILE (&isc_modules[4])
#define ISC_LOGMODULE_OTHER (&isc_modules[5])
ISC_LANG_BEGINDECLS
isc_result_t
isc_log_create(isc_mem_t *mctx, isc_log_t **lctxp, isc_logconfig_t **lcfgp);
/*%<
* Establish a new logging context, with default channels.
*
* Notes:
*\li isc_log_create() calls isc_logconfig_create(), so see its comment
* below for more information.
*
* Requires:
*\li mctx is a valid memory context.
*\li lctxp is not null and *lctxp is null.
*\li lcfgp is null or lcfgp is not null and *lcfgp is null.
*
* Ensures:
*\li *lctxp will point to a valid logging context if all of the necessary
* memory was allocated, or NULL otherwise.
*\li *lcfgp will point to a valid logging configuration if all of the
* necessary memory was allocated, or NULL otherwise.
*\li On failure, no additional memory is allocated.
*
* Returns:
*\li #ISC_R_SUCCESS Success
*\li #ISC_R_NOMEMORY Resource limit: Out of memory
*/
isc_result_t
isc_logconfig_create(isc_log_t *lctx, isc_logconfig_t **lcfgp);
/*%<
* Create the data structure that holds all of the configurable information
* about where messages are actually supposed to be sent -- the information
* that could changed based on some configuration file, as opposed to the
* the category/module specification of isc_log_[v]write[1] that is compiled
* into a program, or the debug_level which is dynamic state information.
*
* Notes:
*\li It is necessary to specify the logging context the configuration
* will be used with because the number of categories and modules
* needs to be known in order to set the configuration. However,
* the configuration is not used by the logging context until the
* isc_logconfig_use function is called.
*
*\li The memory context used for operations that allocate memory for
* the configuration is that of the logging context, as specified
* in the isc_log_create call.
*
*\li Four default channels are established:
*\verbatim
* default_syslog
* - log to syslog's daemon facility #ISC_LOG_INFO or higher
* default_stderr
* - log to stderr #ISC_LOG_INFO or higher
* default_debug
* - log to stderr #ISC_LOG_DEBUG dynamically
* null
* - log nothing
*\endverbatim
*
* Requires:
*\li lctx is a valid logging context.
*\li lcftp is not null and *lcfgp is null.
*
* Ensures:
*\li *lcfgp will point to a valid logging context if all of the necessary
* memory was allocated, or NULL otherwise.
*\li On failure, no additional memory is allocated.
*
* Returns:
*\li #ISC_R_SUCCESS Success
*\li #ISC_R_NOMEMORY Resource limit: Out of memory
*/
isc_logconfig_t *
isc_logconfig_get(isc_log_t *lctx);
/*%<
* Returns a pointer to the configuration currently in use by the log context.
*
* Requires:
*\li lctx is a valid context.
*
* Ensures:
*\li The configuration pointer is non-null.
*
* Returns:
*\li The configuration pointer.
*/
isc_result_t
isc_logconfig_use(isc_log_t *lctx, isc_logconfig_t *lcfg);
/*%<
* Associate a new configuration with a logging context.
*
* Notes:
*\li This is thread safe. The logging context will lock a mutex
* before attempting to swap in the new configuration, and isc_log_doit
* (the internal function used by all of isc_log_[v]write[1]) locks
* the same lock for the duration of its use of the configuration.
*
* Requires:
*\li lctx is a valid logging context.
*\li lcfg is a valid logging configuration.
*\li lctx is the same configuration given to isc_logconfig_create
* when the configuration was created.
*
* Ensures:
*\li Future calls to isc_log_write will use the new configuration.
*
* Returns:
*\li #ISC_R_SUCCESS Success
*\li #ISC_R_NOMEMORY Resource limit: Out of memory
*/
void
isc_log_destroy(isc_log_t **lctxp);
/*%<
* Deallocate the memory associated with a logging context.
*
* Requires:
*\li *lctx is a valid logging context.
*
* Ensures:
*\li All of the memory associated with the logging context is returned
* to the free memory pool.
*
*\li Any open files are closed.
*
*\li The logging context is marked as invalid.
*/
void
isc_logconfig_destroy(isc_logconfig_t **lcfgp);
/*%<
* Destroy a logging configuration.
*
* Notes:
*\li This function cannot be used directly with the return value of
* isc_logconfig_get, because a logging context must always have
* a valid configuration associated with it.
*
* Requires:
*\li lcfgp is not null and *lcfgp is a valid logging configuration.
*\li The logging configuration is not in use by an existing logging context.
*
* Ensures:
*\li All memory allocated for the configuration is freed.
*
*\li The configuration is marked as invalid.
*/
void
isc_log_registercategories(isc_log_t *lctx, isc_logcategory_t categories[]);
/*%<
* Identify logging categories a library will use.
*
* Notes:
*\li A category should only be registered once, but no mechanism enforces
* this rule.
*
*\li The end of the categories array is identified by a NULL name.
*
*\li Because the name is used by #ISC_LOG_PRINTCATEGORY, it should not
* be altered or destroyed after isc_log_registercategories().
*
*\li Because each element of the categories array is used by
* isc_log_categorybyname, it should not be altered or destroyed
* after registration.
*
*\li The value of the id integer in each structure is overwritten
* by this function, and so id need not be initialized to any particular
* value prior to the function call.
*
*\li A subsequent call to isc_log_registercategories with the same
* logging context (but new categories) will cause the last
* element of the categories array from the prior call to have
* its "name" member changed from NULL to point to the new
* categories array, and its "id" member set to UINT_MAX.
*
* Requires:
*\li lctx is a valid logging context.
*\li categories != NULL.
*\li categories[0].name != NULL.
*
* Ensures:
* \li There are references to each category in the logging context,
* so they can be used with isc_log_usechannel() and isc_log_write().
*/
void
isc_log_registermodules(isc_log_t *lctx, isc_logmodule_t modules[]);
/*%<
* Identify logging categories a library will use.
*
* Notes:
*\li A module should only be registered once, but no mechanism enforces
* this rule.
*
*\li The end of the modules array is identified by a NULL name.
*
*\li Because the name is used by #ISC_LOG_PRINTMODULE, it should not
* be altered or destroyed after isc_log_registermodules().
*
*\li Because each element of the modules array is used by
* isc_log_modulebyname, it should not be altered or destroyed
* after registration.
*
*\li The value of the id integer in each structure is overwritten
* by this function, and so id need not be initialized to any particular
* value prior to the function call.
*
*\li A subsequent call to isc_log_registermodules with the same
* logging context (but new modules) will cause the last
* element of the modules array from the prior call to have
* its "name" member changed from NULL to point to the new
* modules array, and its "id" member set to UINT_MAX.
*
* Requires:
*\li lctx is a valid logging context.
*\li modules != NULL.
*\li modules[0].name != NULL;
*
* Ensures:
*\li Each module has a reference in the logging context, so they can be
* used with isc_log_usechannel() and isc_log_write().
*/
isc_result_t
isc_log_createchannel(isc_logconfig_t *lcfg, const char *name,
unsigned int type, int level,
const isc_logdestination_t *destination,
unsigned int flags);
/*%<
* Specify the parameters of a logging channel.
*
* Notes:
*\li The name argument is copied to memory in the logging context, so
* it can be altered or destroyed after isc_log_createchannel().
*
*\li Defining a very large number of channels will have a performance
* impact on isc_log_usechannel(), since the names are searched
* linearly until a match is made. This same issue does not affect
* isc_log_write, however.
*
*\li Channel names can be redefined; this is primarily useful for programs
* that want their own definition of default_syslog, default_debug
* and default_stderr.
*
*\li Any channel that is redefined will not affect logging that was
* already directed to its original definition, _except_ for the
* default_stderr channel. This case is handled specially so that
* the default logging category can be changed by redefining
* default_stderr. (XXXDCL Though now that I think of it, the default
* logging category can be changed with only one additional function
* call by defining a new channel and then calling isc_log_usechannel()
* for #ISC_LOGCATEGORY_DEFAULT.)
*
*\li Specifying #ISC_LOG_PRINTTIME or #ISC_LOG_PRINTTAG for syslog is
* allowed, but probably not what you wanted to do.
*
* #ISC_LOG_DEBUGONLY will mark the channel as usable only when the
* debug level of the logging context (see isc_log_setdebuglevel)
* is non-zero.
*
* Requires:
*\li lcfg is a valid logging configuration.
*
*\li name is not NULL.
*
*\li type is #ISC_LOG_TOSYSLOG, #ISC_LOG_TOFILE, #ISC_LOG_TOFILEDESC or
* #ISC_LOG_TONULL.
*
*\li destination is not NULL unless type is #ISC_LOG_TONULL.
*
*\li level is >= #ISC_LOG_CRITICAL (the most negative logging level).
*
*\li flags does not include any bits aside from the ISC_LOG_PRINT* bits,
* #ISC_LOG_DEBUGONLY or #ISC_LOG_BUFFERED.
*
* Ensures:
*\li #ISC_R_SUCCESS
* A channel with the given name is usable with
* isc_log_usechannel().
*
*\li #ISC_R_NOMEMORY or #ISC_R_UNEXPECTED
* No additional memory is being used by the logging context.
* Any channel that previously existed with the given name
* is not redefined.
*
* Returns:
*\li #ISC_R_SUCCESS Success
*\li #ISC_R_NOMEMORY Resource limit: Out of memory
*\li #ISC_R_UNEXPECTED type was out of range and REQUIRE()
* was disabled.
*/
isc_result_t
isc_log_usechannel(isc_logconfig_t *lcfg, const char *name,
const isc_logcategory_t *category,
const isc_logmodule_t *module);
/*%<
* Associate a named logging channel with a category and module that
* will use it.
*
* Notes:
*\li The name is searched for linearly in the set of known channel names
* until a match is found. (Note the performance impact of a very large
* number of named channels.) When multiple channels of the same
* name are defined, the most recent definition is found.
*
*\li Specifying a very large number of channels for a category will have
* a moderate impact on performance in isc_log_write(), as each
* call looks up the category for the start of a linked list, which
* it follows all the way to the end to find matching modules. The
* test for matching modules is integral, though.
*
*\li If category is NULL, then the channel is associated with the indicated
* module for all known categories (including the "default" category).
*
*\li If module is NULL, then the channel is associated with every module
* that uses that category.
*
*\li Passing both category and module as NULL would make every log message
* use the indicated channel.
*
* \li Specifying a channel that is #ISC_LOG_TONULL for a category/module pair
* has no effect on any other channels associated with that pair,
* regardless of ordering. Thus you cannot use it to "mask out" one
* category/module pair when you have specified some other channel that
* is also used by that category/module pair.
*
* Requires:
*\li lcfg is a valid logging configuration.
*
*\li category is NULL or has an id that is in the range of known ids.
*
* module is NULL or has an id that is in the range of known ids.
*
* Ensures:
*\li #ISC_R_SUCCESS
* The channel will be used by the indicated category/module
* arguments.
*
*\li #ISC_R_NOMEMORY
* If assignment for a specific category has been requested,
* the channel has not been associated with the indicated
* category/module arguments and no additional memory is
* used by the logging context.
* If assignment for all categories has been requested
* then _some_ may have succeeded (starting with category
* "default" and progressing through the order of categories
* passed to isc_log_registercategories()) and additional memory
* is being used by whatever assignments succeeded.
*
* Returns:
*\li #ISC_R_SUCCESS Success
*\li #ISC_R_NOMEMORY Resource limit: Out of memory
*/
/* Attention: next four comments PRECEDE code */
/*!
* \brief
* Write a message to the log channels.
*
* Notes:
*\li Log messages containing natural language text should be logged with
* isc_log_iwrite() to allow for localization.
*
*\li lctx can be NULL; this is allowed so that programs which use
* libraries that use the ISC logging system are not required to
* also use it.
*
*\li The format argument is a printf(3) string, with additional arguments
* as necessary.
*
* Requires:
*\li lctx is a valid logging context.
*
*\li The category and module arguments must have ids that are in the
* range of known ids, as established by isc_log_registercategories()
* and isc_log_registermodules().
*
*\li level != #ISC_LOG_DYNAMIC. ISC_LOG_DYNAMIC is used only to define
* channels, and explicit debugging level must be identified for
* isc_log_write() via ISC_LOG_DEBUG(level).
*
*\li format != NULL.
*
* Ensures:
*\li The log message is written to every channel associated with the
* indicated category/module pair.
*
* Returns:
*\li Nothing. Failure to log a message is not construed as a
* meaningful error.
*/
void
isc_log_write(isc_log_t *lctx, isc_logcategory_t *category,
isc_logmodule_t *module, int level,
const char *format, ...)
ISC_FORMAT_PRINTF(5, 6);
/*%
* Write a message to the log channels.
*
* Notes:
*\li lctx can be NULL; this is allowed so that programs which use
* libraries that use the ISC logging system are not required to
* also use it.
*
*\li The format argument is a printf(3) string, with additional arguments
* as necessary.
*
* Requires:
*\li lctx is a valid logging context.
*
*\li The category and module arguments must have ids that are in the
* range of known ids, as established by isc_log_registercategories()
* and isc_log_registermodules().
*
*\li level != #ISC_LOG_DYNAMIC. ISC_LOG_DYNAMIC is used only to define
* channels, and explicit debugging level must be identified for
* isc_log_write() via ISC_LOG_DEBUG(level).
*
*\li format != NULL.
*
* Ensures:
*\li The log message is written to every channel associated with the
* indicated category/module pair.
*
* Returns:
*\li Nothing. Failure to log a message is not construed as a
* meaningful error.
*/
void
isc_log_vwrite(isc_log_t *lctx, isc_logcategory_t *category,
isc_logmodule_t *module, int level,
const char *format, va_list args)
ISC_FORMAT_PRINTF(5, 0);
/*%
* Write a message to the log channels, pruning duplicates that occur within
* a configurable amount of seconds (see isc_log_[sg]etduplicateinterval).
* This function is otherwise identical to isc_log_write().
*/
void
isc_log_write1(isc_log_t *lctx, isc_logcategory_t *category,
isc_logmodule_t *module, int level, const char *format, ...)
ISC_FORMAT_PRINTF(5, 6);
/*%
* Write a message to the log channels, pruning duplicates that occur within
* a configurable amount of seconds (see isc_log_[sg]etduplicateinterval).
* This function is otherwise identical to isc_log_vwrite().
*/
void
isc_log_vwrite1(isc_log_t *lctx, isc_logcategory_t *category,
isc_logmodule_t *module, int level, const char *format,
va_list args)
ISC_FORMAT_PRINTF(5, 0);
/*%
* These are four internationalized versions of the isc_log_[v]write[1]
* functions.
*
* The only difference is that they take arguments for a message
* catalog, message set, and message number, all immediately preceding the
* format argument. The format argument becomes the default text, a la
* isc_msgcat_get. If the message catalog is NULL, no lookup is attempted
* for a message -- which makes the message set and message number irrelevant,
* and the non-internationalized call should have probably been used instead.
*
* Yes, that means there are now *eight* interfaces to logging a message.
* Sheesh. Make the madness stop!
*/
/*@{*/
void
isc_log_iwrite(isc_log_t *lctx, isc_logcategory_t *category,
isc_logmodule_t *module, int level,
isc_msgcat_t *msgcat, int msgset, int message,
const char *format, ...)
ISC_FORMAT_PRINTF(8, 9);
void
isc_log_ivwrite(isc_log_t *lctx, isc_logcategory_t *category,
isc_logmodule_t *module, int level,
isc_msgcat_t *msgcat, int msgset, int message,
const char *format, va_list args)
ISC_FORMAT_PRINTF(8, 0);
void
isc_log_iwrite1(isc_log_t *lctx, isc_logcategory_t *category,
isc_logmodule_t *module, int level,
isc_msgcat_t *msgcat, int msgset, int message,
const char *format, ...)
ISC_FORMAT_PRINTF(8, 9);
void
isc_log_ivwrite1(isc_log_t *lctx, isc_logcategory_t *category,
isc_logmodule_t *module, int level,
isc_msgcat_t *msgcat, int msgset, int message,
const char *format, va_list args)
ISC_FORMAT_PRINTF(8, 0);
/*@}*/
void
isc_log_setdebuglevel(isc_log_t *lctx, unsigned int level);
/*%<
* Set the debugging level used for logging.
*
* Notes:
*\li Setting the debugging level to 0 disables debugging log messages.
*
* Requires:
*\li lctx is a valid logging context.
*
* Ensures:
*\li The debugging level is set to the requested value.
*/
unsigned int
isc_log_getdebuglevel(isc_log_t *lctx);
/*%<
* Get the current debugging level.
*
* Notes:
*\li This is provided so that a program can have a notion of
* "increment debugging level" or "decrement debugging level"
* without needing to keep track of what the current level is.
*
*\li A return value of 0 indicates that debugging messages are disabled.
*
* Requires:
*\li lctx is a valid logging context.
*
* Ensures:
*\li The current logging debugging level is returned.
*/
bool
isc_log_wouldlog(isc_log_t *lctx, int level);
/*%<
* Determine whether logging something to 'lctx' at 'level' would
* actually cause something to be logged somewhere.
*
* If #false is returned, it is guaranteed that nothing would
* be logged, allowing the caller to omit unnecessary
* isc_log_write() calls and possible message preformatting.
*/
void
isc_log_setduplicateinterval(isc_logconfig_t *lcfg, unsigned int interval);
/*%<
* Set the interval over which duplicate log messages will be ignored
* by isc_log_[v]write1(), in seconds.
*
* Notes:
*\li Increasing the duplicate interval from X to Y will not necessarily
* filter out duplicates of messages logged in Y - X seconds since the
* increase. (Example: Message1 is logged at midnight. Message2
* is logged at 00:01:00, when the interval is only 30 seconds, causing
* Message1 to be expired from the log message history. Then the interval
* is increased to 3000 (five minutes) and at 00:04:00 Message1 is logged
* again. It will appear the second time even though less than five
* passed since the first occurrence.
*
* Requires:
*\li lctx is a valid logging context.
*/
unsigned int
isc_log_getduplicateinterval(isc_logconfig_t *lcfg);
/*%<
* Get the current duplicate filtering interval.
*
* Requires:
*\li lctx is a valid logging context.
*
* Returns:
*\li The current duplicate filtering interval.
*/
isc_result_t
isc_log_settag(isc_logconfig_t *lcfg, const char *tag);
/*%<
* Set the program name or other identifier for #ISC_LOG_PRINTTAG.
*
* Requires:
*\li lcfg is a valid logging configuration.
*
* Notes:
*\li If this function has not set the tag to a non-NULL, non-empty value,
* then the #ISC_LOG_PRINTTAG channel flag will not print anything.
* Unlike some implementations of syslog on Unix systems, you *must* set
* the tag in order to get it logged. It is not implicitly derived from
* the program name (which is pretty impossible to infer portably).
*
*\li Setting the tag to NULL or the empty string will also cause the
* #ISC_LOG_PRINTTAG channel flag to not print anything. If tag equals the
* empty string, calls to isc_log_gettag will return NULL.
*
* Returns:
*\li #ISC_R_SUCCESS Success
*\li #ISC_R_NOMEMORY Resource Limit: Out of memory
*
* XXXDCL when creating a new isc_logconfig_t, it might be nice if the tag
* of the currently active isc_logconfig_t was inherited. this does not
* currently happen.
*/
char *
isc_log_gettag(isc_logconfig_t *lcfg);
/*%<
* Get the current identifier printed with #ISC_LOG_PRINTTAG.
*
* Requires:
*\li lcfg is a valid logging configuration.
*
* Notes:
*\li Since isc_log_settag() will not associate a zero-length string
* with the logging configuration, attempts to do so will cause
* this function to return NULL. However, a determined programmer
* will observe that (currently) a tag of length greater than zero
* could be set, and then modified to be zero length.
*
* Returns:
*\li A pointer to the current identifier, or NULL if none has been set.
*/
void
isc_log_opensyslog(const char *tag, int options, int facility);
/*%<
* Initialize syslog logging.
*
* Notes:
*\li XXXDCL NT
* This is currently equivalent to openlog(), but is not going to remain
* that way. In the meantime, the arguments are all identical to
* those used by openlog(3), as follows:
*
* \code
* tag: The string to use in the position of the program
* name in syslog messages. Most (all?) syslogs
* will use basename(argv[0]) if tag is NULL.
*
* options: LOG_CONS, LOG_PID, LOG_NDELAY ... whatever your
* syslog supports.
*
* facility: The default syslog facility. This is irrelevant
* since isc_log_write will ALWAYS use the channel's
* declared facility.
* \endcode
*
*\li Zero effort has been made (yet) to accommodate systems with openlog()
* that only takes two arguments, or to identify valid syslog
* facilities or options for any given architecture.
*
*\li It is necessary to call isc_log_opensyslog() to initialize
* syslogging on machines which do not support network connections to
* syslogd because they require a Unix domain socket to be used. Since
* this is a chore to determine at run-time, it is suggested that it
* always be called by programs using the ISC logging system.
*
* Requires:
*\li Nothing.
*
* Ensures:
*\li openlog() is called to initialize the syslog system.
*/
void
isc_log_closefilelogs(isc_log_t *lctx);
/*%<
* Close all open files used by #ISC_LOG_TOFILE channels.
*
* Notes:
*\li This function is provided for programs that want to use their own
* log rolling mechanism rather than the one provided internally.
* For example, a program that wanted to keep daily logs would define
* a channel which used #ISC_LOG_ROLLNEVER, then once a day would
* rename the log file and call isc_log_closefilelogs().
*
*\li #ISC_LOG_TOFILEDESC channels are unaffected.
*
* Requires:
*\li lctx is a valid context.
*
* Ensures:
*\li The open files are closed and will be reopened when they are
* next needed.
*/
isc_logcategory_t *
isc_log_categorybyname(isc_log_t *lctx, const char *name);
/*%<
* Find a category by its name.
*
* Notes:
*\li The string name of a category is not required to be unique.
*
* Requires:
*\li lctx is a valid context.
*\li name is not NULL.
*
* Returns:
*\li A pointer to the _first_ isc_logcategory_t structure used by "name".
*
*\li NULL if no category exists by that name.
*/
isc_logmodule_t *
isc_log_modulebyname(isc_log_t *lctx, const char *name);
/*%<
* Find a module by its name.
*
* Notes:
*\li The string name of a module is not required to be unique.
*
* Requires:
*\li lctx is a valid context.
*\li name is not NULL.
*
* Returns:
*\li A pointer to the _first_ isc_logmodule_t structure used by "name".
*
*\li NULL if no module exists by that name.
*/
void
isc_log_setcontext(isc_log_t *lctx);
/*%<
* Sets the context used by the libisc for logging.
*
* Requires:
*\li lctx be a valid context.
*/
isc_result_t
isc_logfile_roll(isc_logfile_t *file);
/*%<
* Roll a logfile.
*
* Requires:
*\li file is not NULL.
*/
ISC_LANG_ENDDECLS
#endif /* ISC_LOG_H */