struct cmd_tbl;
-/** Log levels supported, ranging from most to least important */
+/**
+ * enum log_level_t - Log levels supported, ranging from most to least important
+ */
enum log_level_t {
- LOGL_EMERG = 0, /* U-Boot is unstable */
- LOGL_ALERT, /* Action must be taken immediately */
- LOGL_CRIT, /* Critical conditions */
- LOGL_ERR, /* Error that prevents something from working */
- LOGL_WARNING, /* Warning may prevent optimial operation */
- LOGL_NOTICE, /* Normal but significant condition, printf() */
- LOGL_INFO, /* General information message */
- LOGL_DEBUG, /* Basic debug-level message */
- LOGL_DEBUG_CONTENT, /* Debug message showing full message content */
- LOGL_DEBUG_IO, /* Debug message showing hardware I/O access */
-
+ /** @LOGL_EMERG: U-Boot is unstable */
+ LOGL_EMERG = 0,
+ /** @LOGL_ALERT: Action must be taken immediately */
+ LOGL_ALERT,
+ /** @LOGL_CRIT: Critical conditions */
+ LOGL_CRIT,
+ /** @LOGL_ERR: Error that prevents something from working */
+ LOGL_ERR,
+ /** @LOGL_WARNING: Warning may prevent optimal operation */
+ LOGL_WARNING,
+ /** @LOGL_NOTICE: Normal but significant condition, printf() */
+ LOGL_NOTICE,
+ /** @LOGL_INFO: General information message */
+ LOGL_INFO,
+ /** @LOGL_DEBUG: Basic debug-level message */
+ LOGL_DEBUG,
+ /** @LOGL_DEBUG_CONTENT: Debug message showing full message content */
+ LOGL_DEBUG_CONTENT,
+ /** @LOGL_DEBUG_IO: Debug message showing hardware I/O access */
+ LOGL_DEBUG_IO,
+
+ /** @LOGL_COUNT: Total number of valid log levels */
LOGL_COUNT,
+ /** @LOGL_NONE: Used to indicate that there is no valid log level */
LOGL_NONE,
- LOGL_LEVEL_MASK = 0xf, /* Mask for valid log levels */
- LOGL_FORCE_DEBUG = 0x10, /* Mask to force output due to LOG_DEBUG */
+ /** @LOGL_LEVEL_MASK: Mask for valid log levels */
+ LOGL_LEVEL_MASK = 0xf,
+ /** @LOGL_FORCE_DEBUG: Mask to force output due to LOG_DEBUG */
+ LOGL_FORCE_DEBUG = 0x10,
+ /** @LOGL_FIRST: The first, most-important log level */
LOGL_FIRST = LOGL_EMERG,
+ /** @LOGL_MAX: The last, least-important log level */
LOGL_MAX = LOGL_DEBUG_IO,
+ /** @LOGL_CONT: Use same log level as in previous call */
+ LOGL_CONT = -1,
};
/**
- * Log categories supported. Most of these correspond to uclasses (i.e.
- * enum uclass_id) but there are also some more generic categories
+ * enum log_category_t - Log categories supported.
+ *
+ * Log categories between %LOGC_FIRST and %LOGC_NONE correspond to uclasses
+ * (i.e. &enum uclass_id), but there are also some more generic categories.
+ *
+ * Remember to update log_cat_name[] after adding a new category.
*/
enum log_category_t {
+ /** @LOGC_FIRST: First log category */
LOGC_FIRST = 0, /* First part mirrors UCLASS_... */
+ /** @LOGC_NONE: Default log category */
LOGC_NONE = UCLASS_COUNT, /* First number is after all uclasses */
- LOGC_ARCH, /* Related to arch-specific code */
- LOGC_BOARD, /* Related to board-specific code */
- LOGC_CORE, /* Related to core features (non-driver-model) */
- LOGC_DM, /* Core driver-model */
- LOGC_DT, /* Device-tree */
- LOGC_EFI, /* EFI implementation */
- LOGC_ALLOC, /* Memory allocation */
- LOGC_SANDBOX, /* Related to the sandbox board */
- LOGC_BLOBLIST, /* Bloblist */
- LOGC_DEVRES, /* Device resources (devres_... functions) */
- /* Advanced Configuration and Power Interface (ACPI) */
+ /** @LOGC_ARCH: Related to arch-specific code */
+ LOGC_ARCH,
+ /** @LOGC_BOARD: Related to board-specific code */
+ LOGC_BOARD,
+ /** @LOGC_CORE: Related to core features (non-driver-model) */
+ LOGC_CORE,
+ /** @LOGC_DM: Core driver-model */
+ LOGC_DM,
+ /** @LOGC_DT: Device-tree */
+ LOGC_DT,
+ /** @LOGC_EFI: EFI implementation */
+ LOGC_EFI,
+ /** @LOGC_ALLOC: Memory allocation */
+ LOGC_ALLOC,
+ /** @LOGC_SANDBOX: Related to the sandbox board */
+ LOGC_SANDBOX,
+ /** @LOGC_BLOBLIST: Bloblist */
+ LOGC_BLOBLIST,
+ /** @LOGC_DEVRES: Device resources (``devres_...`` functions) */
+ LOGC_DEVRES,
+ /** @LOGC_ACPI: Advanced Configuration and Power Interface (ACPI) */
LOGC_ACPI,
-
- LOGC_COUNT, /* Number of log categories */
- LOGC_END, /* Sentinel value for a list of log categories */
+ /** @LOGC_BOOT: Related to boot process / boot image processing */
+ LOGC_BOOT,
+ /** @LOGC_EVENT: Related to event and event handling */
+ LOGC_EVENT,
+ /** @LOGC_COUNT: Number of log categories */
+ LOGC_COUNT,
+ /** @LOGC_END: Sentinel value for lists of log categories */
+ LOGC_END,
+ /** @LOGC_CONT: Use same category as in previous call */
+ LOGC_CONT = -1,
};
/* Helper to cast a uclass ID to a log category */
* @func: Function where log record was generated
* @fmt: printf() format string for log record
* @...: Optional parameters, according to the format string @fmt
- * @return 0 if log record was emitted, -ve on error
+ * Return: 0 if log record was emitted, -ve on error
*/
int _log(enum log_category_t cat, enum log_level_t level, const char *file,
int line, const char *func, const char *fmt, ...)
return 0;
}
+/**
+ * _log_buffer - Internal function to print data buffer in hex and ascii form
+ *
+ * @cat: Category of log record (indicating which subsystem generated it)
+ * @level: Level of log record (indicating its severity)
+ * @file: File name of file where log record was generated
+ * @line: Line number in file where log record was generated
+ * @func: Function where log record was generated
+ * @addr: Starting address to display at start of line
+ * @data: pointer to data buffer
+ * @width: data value width. May be 1, 2, or 4.
+ * @count: number of values to display
+ * @linelen: Number of values to print per line; specify 0 for default length
+ */
+int _log_buffer(enum log_category_t cat, enum log_level_t level,
+ const char *file, int line, const char *func, ulong addr,
+ const void *data, uint width, uint count, uint linelen);
+
/* Define this at the top of a file to add a prefix to debug messages */
#ifndef pr_fmt
#define pr_fmt(fmt) fmt
*/
#if CONFIG_IS_ENABLED(LOG)
#define _LOG_MAX_LEVEL CONFIG_VAL(LOG_MAX_LEVEL)
+#else
+#define _LOG_MAX_LEVEL LOGL_INFO
+#endif
+
+#define log_emer(_fmt...) log(LOG_CATEGORY, LOGL_EMERG, ##_fmt)
+#define log_alert(_fmt...) log(LOG_CATEGORY, LOGL_ALERT, ##_fmt)
+#define log_crit(_fmt...) log(LOG_CATEGORY, LOGL_CRIT, ##_fmt)
#define log_err(_fmt...) log(LOG_CATEGORY, LOGL_ERR, ##_fmt)
#define log_warning(_fmt...) log(LOG_CATEGORY, LOGL_WARNING, ##_fmt)
#define log_notice(_fmt...) log(LOG_CATEGORY, LOGL_NOTICE, ##_fmt)
#define log_debug(_fmt...) log(LOG_CATEGORY, LOGL_DEBUG, ##_fmt)
#define log_content(_fmt...) log(LOG_CATEGORY, LOGL_DEBUG_CONTENT, ##_fmt)
#define log_io(_fmt...) log(LOG_CATEGORY, LOGL_DEBUG_IO, ##_fmt)
-#else
-#define _LOG_MAX_LEVEL LOGL_INFO
-#define log_err(_fmt, ...) printf(_fmt, ##__VA_ARGS__)
-#define log_warning(_fmt, ...) printf(_fmt, ##__VA_ARGS__)
-#define log_notice(_fmt, ...) printf(_fmt, ##__VA_ARGS__)
-#define log_info(_fmt, ...) printf(_fmt, ##__VA_ARGS__)
-#define log_debug(_fmt, ...) debug(_fmt, ##__VA_ARGS__)
-#define log_content(_fmt...) log_nop(LOG_CATEGORY, \
- LOGL_DEBUG_CONTENT, ##_fmt)
-#define log_io(_fmt...) log_nop(LOG_CATEGORY, LOGL_DEBUG_IO, ##_fmt)
-#endif
+#define log_cont(_fmt...) log(LOGC_CONT, LOGL_CONT, ##_fmt)
-#if CONFIG_IS_ENABLED(LOG)
#ifdef LOG_DEBUG
#define _LOG_DEBUG LOGL_FORCE_DEBUG
#else
#define _LOG_DEBUG 0
#endif
+#if CONFIG_IS_ENABLED(LOG)
+
/* Emit a log record if the level is less that the maximum */
#define log(_cat, _level, _fmt, _args...) ({ \
int _l = _level; \
- if (CONFIG_IS_ENABLED(LOG) && \
- (_LOG_DEBUG != 0 || _l <= _LOG_MAX_LEVEL)) \
+ if (_LOG_DEBUG != 0 || _l <= _LOG_MAX_LEVEL) \
_log((enum log_category_t)(_cat), \
(enum log_level_t)(_l | _LOG_DEBUG), __FILE__, \
__LINE__, __func__, \
pr_fmt(_fmt), ##_args); \
})
+
+/* Emit a dump if the level is less that the maximum */
+#define log_buffer(_cat, _level, _addr, _data, _width, _count, _linelen) ({ \
+ int _l = _level; \
+ if (_LOG_DEBUG != 0 || _l <= _LOG_MAX_LEVEL) \
+ _log_buffer((enum log_category_t)(_cat), \
+ (enum log_level_t)(_l | _LOG_DEBUG), __FILE__, \
+ __LINE__, __func__, _addr, _data, \
+ _width, _count, _linelen); \
+ })
#else
-#define log(_cat, _level, _fmt, _args...)
+
+/* Note: _LOG_DEBUG != 0 avoids a warning with clang */
+#define log(_cat, _level, _fmt, _args...) ({ \
+ int _l = _level; \
+ if (_LOG_DEBUG != 0 || _l <= LOGL_INFO || \
+ (_DEBUG && _l == LOGL_DEBUG)) \
+ printf(_fmt, ##_args); \
+ })
+
+#define log_buffer(_cat, _level, _addr, _data, _width, _count, _linelen) ({ \
+ int _l = _level; \
+ if (_LOG_DEBUG != 0 || _l <= LOGL_INFO || \
+ (_DEBUG && _l == LOGL_DEBUG)) \
+ print_buffer(_addr, _data, _width, _count, _linelen); \
+ })
#endif
#define log_nop(_cat, _level, _fmt, _args...) ({ \
#define _SPL_BUILD 0
#endif
-#if !_DEBUG && CONFIG_IS_ENABLED(LOG)
+#if CONFIG_IS_ENABLED(LOG)
-#define debug_cond(cond, fmt, args...) \
- do { \
- if (1) \
- log(LOG_CATEGORY, LOGL_DEBUG, fmt, ##args); \
- } while (0)
+#define debug_cond(cond, fmt, args...) \
+({ \
+ if (cond) \
+ log(LOG_CATEGORY, \
+ (enum log_level_t)(LOGL_FORCE_DEBUG | _LOG_DEBUG), \
+ fmt, ##args); \
+})
#else /* _DEBUG */
* computed by a preprocessor in the best case, allowing for the best
* optimization.
*/
-#define debug_cond(cond, fmt, args...) \
- do { \
- if (cond) \
- printf(pr_fmt(fmt), ##args); \
- } while (0)
+#define debug_cond(cond, fmt, args...) \
+({ \
+ if (cond) \
+ printf(pr_fmt(fmt), ##args); \
+})
#endif /* _DEBUG */
* full pathname as it may be huge. Only use this when the user should be
* warning, similar to BUG_ON() in linux.
*
- * @return true if assertion succeeded (condition is true), else false
+ * Return: true if assertion succeeded (condition is true), else false
*/
#define assert_noisy(x) \
({ bool _val = (x); \
__ret); \
__ret; \
})
+
+/*
+ * Similar to the above, but any non-zero value is consider an error, not just
+ * values less than 0.
+ */
+#define log_retz(_ret) ({ \
+ int __ret = (_ret); \
+ if (__ret) \
+ log(LOG_CATEGORY, LOGL_ERR, "returning err=%d\n", __ret); \
+ __ret; \
+ })
+#define log_msg_retz(_msg, _ret) ({ \
+ int __ret = (_ret); \
+ if (__ret) \
+ log(LOG_CATEGORY, LOGL_ERR, "%s: returning err=%d\n", _msg, \
+ __ret); \
+ __ret; \
+ })
#else
/* Non-logging versions of the above which just return the error code */
#define log_ret(_ret) (_ret)
#define log_msg_ret(_msg, _ret) ((void)(_msg), _ret)
+#define log_retz(_ret) (_ret)
+#define log_msg_retz(_msg, _ret) ((void)(_msg), _ret)
#endif
+/** * enum log_rec_flags - Flags for a log record */
+enum log_rec_flags {
+ /** @LOGRECF_FORCE_DEBUG: Force output of debug record */
+ LOGRECF_FORCE_DEBUG = BIT(0),
+ /** @LOGRECF_CONT: Continuation of previous log record */
+ LOGRECF_CONT = BIT(1),
+};
+
/**
* struct log_rec - a single log record
*
*
* Members marked as 'not allocated' are stored as pointers and the caller is
* responsible for making sure that the data pointed to is not overwritten.
- * Memebers marked as 'allocated' are allocated (e.g. via strdup()) by the log
+ * Members marked as 'allocated' are allocated (e.g. via strdup()) by the log
* system.
*
*
* @cat: Category, representing a uclass or part of U-Boot
* @level: Severity level, less severe is higher
- * @force_debug: Force output of debug
- * @file: Name of file where the log record was generated (not allocated)
* @line: Line number where the log record was generated
+ * @flags: Flags for log record (enum log_rec_flags)
+ * @file: Name of file where the log record was generated (not allocated)
* @func: Function where the log record was generated (not allocated)
* @msg: Log message (allocated)
*/
struct log_rec {
enum log_category_t cat;
enum log_level_t level;
- bool force_debug;
+ u16 line;
+ u8 flags;
const char *file;
- int line;
const char *func;
const char *msg;
};
struct log_device;
+enum log_device_flags {
+ LOGDF_ENABLE = BIT(0), /* Device is enabled */
+};
+
/**
* struct log_driver - a driver which accepts and processes log records
*
* @name: Name of driver
+ * @emit: Method to call to emit a log record via this device
+ * @flags: Initial value for flags (use LOGDF_ENABLE to enable on start-up)
*/
struct log_driver {
const char *name;
+
/**
- * emit() - emit a log record
+ * @emit: emit a log record
*
* Called by the log system to pass a log record to a particular driver
* for processing. The filter is checked before calling this function.
*/
int (*emit)(struct log_device *ldev, struct log_rec *rec);
+ unsigned short flags;
};
/**
* the run-time aspects of drivers (currently just a list of filters to apply
* to records send to this device).
*
- * @next_filter_num: Seqence number of next filter filter added (0=no filters
+ * @next_filter_num: Sequence number of next filter filter added (0=no filters
* yet). This increments with each new filter on the device, but never
* decrements
+ * @flags: Flags for this filter (enum log_device_flags)
* @drv: Pointer to driver for this device
* @filter_head: List of filters for this device
* @sibling_node: Next device in the list of all devices
*/
struct log_device {
- int next_filter_num;
+ unsigned short next_filter_num;
+ unsigned short flags;
struct log_driver *drv;
struct list_head filter_head;
struct list_head sibling_node;
LOGF_MAX_CATEGORIES = 5, /* maximum categories per filter */
};
+/**
+ * enum log_filter_flags - Flags which modify a filter
+ */
enum log_filter_flags {
- LOGFF_HAS_CAT = 1 << 0, /* Filter has a category list */
+ /** @LOGFF_HAS_CAT: Filter has a category list */
+ LOGFF_HAS_CAT = 1 << 0,
+ /** @LOGFF_DENY: Filter denies matching messages */
+ LOGFF_DENY = 1 << 1,
+ /** @LOGFF_LEVEL_MIN: Filter's level is a minimum, not a maximum */
+ LOGFF_LEVEL_MIN = 1 << 2,
};
/**
- * struct log_filter - criterial to filter out log messages
+ * struct log_filter - criteria to filter out log messages
+ *
+ * If a message matches all criteria, then it is allowed. If LOGFF_DENY is set,
+ * then it is denied instead.
*
* @filter_num: Sequence number of this filter. This is returned when adding a
* new filter, and must be provided when removing a previously added
* filter.
- * @flags: Flags for this filter (LOGFF_...)
- * @cat_list: List of categories to allow (terminated by LOGC_none). If empty
- * then all categories are permitted. Up to LOGF_MAX_CATEGORIES entries
+ * @flags: Flags for this filter (``LOGFF_...``)
+ * @cat_list: List of categories to allow (terminated by %LOGC_END). If empty
+ * then all categories are permitted. Up to %LOGF_MAX_CATEGORIES entries
* can be provided
- * @max_level: Maximum log level to allow
+ * @level: Maximum (or minimum, if %LOGFF_MIN_LEVEL) log level to allow
* @file_list: List of files to allow, separated by comma. If NULL then all
* files are permitted
* @sibling_node: Next filter in the list of filters for this log device
int filter_num;
int flags;
enum log_category_t cat_list[LOGF_MAX_CATEGORIES];
- enum log_level_t max_level;
+ enum log_level_t level;
const char *file_list;
struct list_head sibling_node;
};
#define LOG_DRIVER(_name) \
ll_entry_declare(struct log_driver, _name, log_driver)
+/* Get a pointer to a given driver */
+#define LOG_GET_DRIVER(__name) \
+ ll_entry_get(struct log_driver, __name, log_driver)
+
/**
* log_get_cat_name() - Get the name of a category
*
* @cat: Category to look up
- * @return category name (which may be a uclass driver name) if found, or
- * "<invalid>" if invalid, or "<missing>" if not found
+ * Return: category name (which may be a uclass driver name) if found, or
+ * "<invalid>" if invalid, or "<missing>" if not found. All error
+ * responses begin with '<'.
*/
const char *log_get_cat_name(enum log_category_t cat);
* log_get_cat_by_name() - Look up a category by name
*
* @name: Name to look up
- * @return category ID, or LOGC_NONE if not found
+ * Return: Category, or %LOGC_NONE if not found
*/
enum log_category_t log_get_cat_by_name(const char *name);
* log_get_level_name() - Get the name of a log level
*
* @level: Log level to look up
- * @return log level name (in ALL CAPS)
+ * Return: Log level name (in ALL CAPS)
*/
const char *log_get_level_name(enum log_level_t level);
* log_get_level_by_name() - Look up a log level by name
*
* @name: Name to look up
- * @return log level ID, or LOGL_NONE if not found
+ * Return: Log level, or %LOGL_NONE if not found
*/
enum log_level_t log_get_level_by_name(const char *name);
+/**
+ * log_device_find_by_name() - Look up a log device by its driver's name
+ *
+ * @drv_name: Name of the driver
+ * Return: the log device, or %NULL if not found
+ */
+struct log_device *log_device_find_by_name(const char *drv_name);
+
+/**
+ * log_has_cat() - check if a log category exists within a list
+ *
+ * @cat_list: List of categories to check, at most %LOGF_MAX_CATEGORIES entries
+ * long, terminated by %LC_END if fewer
+ * @cat: Category to search for
+ *
+ * Return: ``true`` if @cat is in @cat_list, else ``false``
+ */
+bool log_has_cat(enum log_category_t cat_list[], enum log_category_t cat);
+
+/**
+ * log_has_file() - check if a file is with a list
+ *
+ * @file_list: List of files to check, separated by comma
+ * @file: File to check for. This string is matched against the end of each
+ * file in the list, i.e. ignoring any preceding path. The list is
+ * intended to consist of relative pathnames, e.g. common/main.c,cmd/log.c
+ *
+ * Return: ``true`` if @file is in @file_list, else ``false``
+ */
+bool log_has_file(const char *file_list, const char *file);
+
/* Log format flags (bit numbers) for gd->log_fmt. See log_fmt_chars */
enum log_fmt {
LOGF_CAT = 0,
/* Handle the 'log test' command */
int do_log_test(struct cmd_tbl *cmdtp, int flag, int argc, char *const argv[]);
+/**
+ * log_add_filter_flags() - Add a new filter to a log device, specifying flags
+ *
+ * @drv_name: Driver name to add the filter to (since each driver only has a
+ * single device)
+ * @flags: Flags for this filter (``LOGFF_...``)
+ * @cat_list: List of categories to allow (terminated by %LOGC_END). If empty
+ * then all categories are permitted. Up to %LOGF_MAX_CATEGORIES entries
+ * can be provided
+ * @level: Maximum (or minimum, if %LOGFF_LEVEL_MIN) log level to allow
+ * @file_list: List of files to allow, separated by comma. If NULL then all
+ * files are permitted
+ * Return:
+ * the sequence number of the new filter (>=0) if the filter was added, or a
+ * -ve value on error
+ */
+int log_add_filter_flags(const char *drv_name, enum log_category_t cat_list[],
+ enum log_level_t level, const char *file_list,
+ int flags);
+
/**
* log_add_filter() - Add a new filter to a log device
*
* @drv_name: Driver name to add the filter to (since each driver only has a
* single device)
- * @cat_list: List of categories to allow (terminated by LOGC_none). If empty
- * then all categories are permitted. Up to LOGF_MAX_CATEGORIES entries
+ * @cat_list: List of categories to allow (terminated by %LOGC_END). If empty
+ * then all categories are permitted. Up to %LOGF_MAX_CATEGORIES entries
* can be provided
* @max_level: Maximum log level to allow
- * @file_list: List of files to allow, separated by comma. If NULL then all
+ * @file_list: List of files to allow, separated by comma. If %NULL then all
* files are permitted
- * @return the sequence number of the new filter (>=0) if the filter was added,
- * or a -ve value on error
+ * Return:
+ * the sequence number of the new filter (>=0) if the filter was added, or a
+ * -ve value on error
*/
-int log_add_filter(const char *drv_name, enum log_category_t cat_list[],
- enum log_level_t max_level, const char *file_list);
+static inline int log_add_filter(const char *drv_name,
+ enum log_category_t cat_list[],
+ enum log_level_t max_level,
+ const char *file_list)
+{
+ return log_add_filter_flags(drv_name, cat_list, max_level, file_list,
+ 0);
+}
/**
* log_remove_filter() - Remove a filter from a log device
* @drv_name: Driver name to remove the filter from (since each driver only has
* a single device)
* @filter_num: Filter number to remove (as returned by log_add_filter())
- * @return 0 if the filter was removed, -ENOENT if either the driver or the
- * filter number was not found
+ * Return:
+ * 0 if the filter was removed, -%ENOENT if either the driver or the filter
+ * number was not found
*/
int log_remove_filter(const char *drv_name, int filter_num);
+/**
+ * log_device_set_enable() - Enable or disable a log device
+ *
+ * Devices are referenced by their driver, so use LOG_GET_DRIVER(name) to pass
+ * the driver to this function. For example if the driver is declared with
+ * LOG_DRIVER(wibble) then pass LOG_GET_DRIVER(wibble) here.
+ *
+ * @drv: Driver of device to enable
+ * @enable: true to enable, false to disable
+ * Return: 0 if OK, -ENOENT if the driver was not found
+ */
+int log_device_set_enable(struct log_driver *drv, bool enable);
+
#if CONFIG_IS_ENABLED(LOG)
/**
* log_init() - Set up the log system ready for use
*
- * @return 0 if OK, -ENOMEM if out of memory
+ * Return: 0 if OK, -%ENOMEM if out of memory
*/
int log_init(void);
#else
* log_get_default_format() - get default log format
*
* The default log format is configurable via
- * CONFIG_LOGF_FILE, CONFIG_LOGF_LINE, CONFIG_LOGF_FUNC.
+ * %CONFIG_LOGF_FILE, %CONFIG_LOGF_LINE, and %CONFIG_LOGF_FUNC.
*
* Return: default log format
*/