log.h revision 5fe5a0c02634eaadfcbc3528bf2c184557110a3b
* Severity levels, patterned after Unix's syslog levels. * ISC_LOG_DYNAMIC can only be used for defining channels with * isc_log_createchannel(), not to specify a level in isc_log_write(). * 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. * A logging context. Details are internal to the implementation. * Channel configuration. Details are internal to the implementation. * 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. * Similar to isc_logcategory above, but for all the modules a library defines. * 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. FILE *
stream;
/* Initialized to NULL for ISC_LOG_TOFILE. */ 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. * Passed to isc_log_createchannel to define the attributes of either * a stdio or a syslog log. * The built-in categories of libisc.a. Currently only one is available, * the category named "default". * Each library registering categories should provide library_LOGCATEGORY_name * definitions with indexes into its isc_logcategory structure corresponding to * the order of the names. This should also be done for modules, but currently * libisc.a has no defined modules. * Establish a new logging context, with default channels. * isc_log_create calls isc_logconfig_create, so see its comment * below for more information. * mctx is a valid memory context. * lctxp is not null and *lctxp is null. * lctfg is not null and *lcfgp is null. * *lctxp will point to a valid logging context if all of the necessary * memory was allocated, or NULL otherwise. * *lcfgp will point to a valid logging context if all of the necessary * memory was allocated, or NULL otherwise. * On failure, no additional memory is allocated. * ISC_R_NOMEMORY Resource limit: Out of memory * 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. * 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. * 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. * Four default channels are established: * - log to syslog's daemon facility LOG_INFO or higher * - log to stderr LOG_INFO or higher * - log to stderr LOG_DEBUG dynamically * lctx is a valid logging context. * lcftp is not null and *lcfgp is null. * *lcfgp will point to a valid logging context if all of the necessary * memory was allocated, or NULL otherwise. * On failure, no additional memory is allocated. * ISC_R_NOMEMORY Resource limit: Out of memory * Returns a pointer to the configuration currently in use by the log context. * lctx is a valid context. * The configuration pointer is non-null. * The configuration pointer. * Associate a new configuration with a logging context. * 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. * lctx is a valid logging context. * lcfg is a valid logging configuration. * lctx is the same configuration given to isc_logconfig_create * when the configuration was created. * Future calls to isc_log_write will use the new configuration. * ISC_R_NOMEMORY Resource limit: Out of memory * Deallocate the memory associated with a logging context. * *lctx is a valid logging context. * All of the memory associated with the logging context is returned * to the free memory pool. * Any open files are closed. * The logging context is marked as invalid. * Destroy a logging configuration. * 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. * lcfgp is not null and *lcfgp is a valid logging configuration. * The logging configuration is not in use by an existing logging context. * All memory allocated for the configuration is freed. * The configuration is marked as invalid. * Identify logging categories a library will use. * A category should only be registered once, but no mechanism enforces * The end of the categories array is identified by a NULL name. * Because the name is used by ISC_LOG_PRINTCATEGORY, it should not * be altered or destroyed after isc_log_registercategories(). * Because each element of the categories array is used by * isc_log_categorybyname, it should not be altered or destroyed * The value of the id integer in each structure is overwritten * by this function, and so id need not be initalized to any particular * value prior to the function call. * 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. * lctx is a valid logging context. * categories[0].name != NULL. * There are references to each category in the logging context, * so they can be used with isc_log_usechannel() and isc_log_write(). * Identify logging categories a library will use. * A module should only be registered once, but no mechanism enforces * The end of the modules array is identified by a NULL name. * Because the name is used by ISC_LOG_PRINTMODULE, it should not * be altered or destroyed after isc_log_registermodules(). * Because each element of the modules array is used by * isc_log_modulebyname, it should not be altered or destroyed * The value of the id integer in each structure is overwritten * by this function, and so id need not be initalized to any particular * value prior to the function call. * 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. * lctx is a valid logging context. * modules[0].name != NULL; * Each module has a reference in the logging context, so they can be * used with isc_log_usechannel() and isc_log_write(). * Specify the parameters of a logging channel. * The name argument is copied to memory in the logging context, so * it can be altered or destroyed after isc_log_createchannel(). * 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. * Channel names can be redefined; this is primarily useful for programs * that want their own definition of default_syslog, default_debug * 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.) * Specifying ISC_LOG_PRINTTIME 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) * lcfg is a valid logging configuration. * type is ISC_LOG_TOSYSLOG, ISC_LOG_TOFILE, ISC_LOG_TOFILEDESC or * destination is not NULL unless type is ISC_LOG_TONULL. * level is >= ISC_LOG_CRITICAL (the most negative logging level). * flags does not include any bits aside from the ISC_LOG_PRINT* bits * A channel with the given name is usable with * 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 * ISC_R_NOMEMORY Resource limit: Out of memory * ISC_R_UNEXPECTED type was out of range and REQUIRE() * Associate a named logging channel with a category and module that * 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. * Specifing 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. * If category is NULL, then the channel is associated with the indicated * module for all known categories (including the "default" category). * If module is NULL, then the channel is associated with every module * that uses that category. * Passing both category and module as NULL would make every log message * use the indicated channel. * 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 * lcfg is a valid logging configuration. * 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. * If assignment for a specific category has been requested, * the channel has not been associated with the indicated * 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. * ISC_R_NOMEMORY Resource limit: Out of memory * Write a message to the log channels. * lctx can be NULL; this is allowed so that programs which use * libraries that use the ISC logging system are not required to * The format argument is a printf(3) string, with additional arguments * lctx is a valid logging context. * The category and module arguments must have ids that are in the * range of known ids, as estabished by isc_log_registercategories() * and isc_log_registermodules(). * 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). * The log message is written to every channel associated with the * Nothing. Failure to log a message is not construed as a * Write a message to the log channels. * lctx can be NULL; this is allowed so that programs which use * libraries that use the ISC logging system are not required to * The format argument is a printf(3) string, with additional arguments * lctx is a valid logging context. * The category and module arguments must have ids that are in the * range of known ids, as estabished by isc_log_registercategories() * and isc_log_registermodules(). * 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). * The log message is written to every channel associated with the * Nothing. Failure to log a message is not construed as a * 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(). * 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(). * Set the debugging level used for logging. * Setting the debugging level to 0 disables debugging log messages. * lctx is a valid logging context. * The debugging level is set to the requested value. * Get the current debugging level. * 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. * A return value of 0 indicates that debugging messages are disabled. * lctx is a valid logging context. * The current logging debugging level is returned. * Set the interval over which duplicate log messages will be ignored * by isc_log_[v]write1(), in seconds. * 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. * lctx is a valid logging context. * The duplicate interval is set to the current * Get the current duplicate filtering interval. * lctx is a valid logging context. * The current duplicate filtering interval is returned. * Initialize syslog logging. * 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: * 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 * facility: The default syslog facility. This is irrelevant * since isc_log_write will ALWAYS use the channel's * Zero effort has been made (yet) to accomodate systems with openlog() * that only takes two arguments, or to identify valid syslog * facilities or options for any given architecture. * 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. * openlog() is called to initialize the syslog system. * Close all open files used by ISC_LOG_TOFILE channels. * 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(). * ISC_LOG_TOFILEDESC channels are unaffected. * lctx is a valid context. * The open files are closed and will be reopened when they are * Find a category by its name. * The string name of a category is not required to be unique. * lctx is a valid context. * A pointer to the _first_ isc_logcategory_t structure used by "name". * NULL if no category exists by that name. * Find a module by its name. * The string name of a module is not required to be unique. * lctx is a valid context. * A pointer to the _first_ isc_logmodule_t structure used by "name". * NULL if no module exists by that name.