ulog记录（RTTulog部分）

ulog.h

int ulog_init(void);
int ulog_async_init(void);
void ulog_output_lock_enabled(rt_bool_t enabled);
void ulog_deinit(void);

log初始化、异步初始化、输出锁初始化、log反初始化；

#define LOG_E(...)                      ulog_e(LOG_TAG, __VA_ARGS__)
#define LOG_W(...)                      ulog_w(LOG_TAG, __VA_ARGS__)
#define LOG_I(...)                      ulog_i(LOG_TAG, __VA_ARGS__)
#define LOG_D(...)                      ulog_d(LOG_TAG, __VA_ARGS__)
#define LOG_RAW(...)                    ulog_raw(__VA_ARGS__)
#define LOG_HEX(name, width, buf, size) ulog_hex(name, width, buf, size)

这段代码定义了一组宏，用于输出日志信息。这些宏的作用是将相应的日志级别和日志标签（`LOG_TAG`）与实际的日志输出函数关联起来。

- `LOG_E` 宏用于输出错误级别的日志信息，对应的日志输出函数是 `ulog_e`。
- `LOG_W` 宏用于输出警告级别的日志信息，对应的日志输出函数是 `ulog_w`。
- `LOG_I` 宏用于输出信息级别的日志信息，对应的日志输出函数是 `ulog_i`。
- `LOG_D` 宏用于输出调试级别的日志信息，对应的日志输出函数是 `ulog_d`。
- `LOG_RAW` 宏用于直接输出原始日志信息，对应的日志输出函数是 `ulog_raw`。
- `LOG_HEX` 宏用于以十六进制格式输出缓冲区的内容，对应的日志输出函数是 `ulog_hex`。

这些宏的定义通过传递可变参数 `__VA_ARGS__` 来支持不同数量和类型的参数。例如，使用 `LOG_I("Hello, %s!", "world")` 将会调用 `ulog_i` 函数输出信息级别的日志信息，其中的格式化字符串是 "Hello, %s!"，参数 "world" 会替换 `%s`。具体的日志输出函数的实现需要根据代码中的其他部分来确定。

 

rt_err_t ulog_backend_register(ulog_backend_t backend, const char *name, rt_bool_t support_color);
rt_err_t ulog_backend_unregister(ulog_backend_t backend);
rt_err_t ulog_backend_set_filter(ulog_backend_t backend, ulog_backend_filter_t filter);
ulog_backend_t ulog_backend_find(const char *name);

这段代码定义了一组函数，用于注册、注销、设置过滤器和查找日志后端。

- `rt_err_t ulog_backend_register(ulog_backend_t backend, const char *name, rt_bool_t support_color)` 函数用于注册一个日志后端。参数 `backend` 是要注册的日志后端对象，`name` 是该后端的名称，`support_color` 是一个布尔值，表示该后端是否支持颜色输出。函数返回一个错误码，表示注册是否成功。

- `rt_err_t ulog_backend_unregister(ulog_backend_t backend)` 函数用于注销一个已注册的日志后端。参数 `backend` 是要注销的日志后端对象。函数返回一个错误码，表示注销是否成功。

- `rt_err_t ulog_backend_set_filter(ulog_backend_t backend, ulog_backend_filter_t filter)` 函数用于设置日志后端的过滤器。参数 `backend` 是要设置过滤器的日志后端对象，`filter` 是一个函数指针，用于指定过滤器的实现。函数返回一个错误码，表示设置过滤器是否成功。

- `ulog_backend_t ulog_backend_find(const char *name)` 函数用于根据名称查找已注册的日志后端。参数 `name` 是要查找的后端名称。如果找到匹配的后端，则返回该后端对象；如果未找到匹配的后端，则返回 NULL。

这些函数的具体实现需要根据代码中的其他部分来确定。这些函数的作用是为日志系统提供灵活的后端管理和配置功能，可以根据需要注册、注销、设置过滤器和查找不同的日志输出后端。

#ifdef ULOG_USING_FILTER
/*
 * log filter setting
 */
int ulog_tag_lvl_filter_set(const char *tag, rt_uint32_t level);
rt_uint32_t ulog_tag_lvl_filter_get(const char *tag);
rt_slist_t *ulog_tag_lvl_list_get(void);
void ulog_global_filter_lvl_set(rt_uint32_t level);
rt_uint32_t ulog_global_filter_lvl_get(void);
void ulog_global_filter_tag_set(const char *tag);
const char *ulog_global_filter_tag_get(void);
void ulog_global_filter_kw_set(const char *keyword);
const char *ulog_global_filter_kw_get(void);
#endif /* ULOG_USING_FILTER */

这段代码是在条件编译宏 `ULOG_USING_FILTER` 的条件下定义的一组函数。这些函数用于设置和获取日志过滤器的配置，并提供了一些全局的过滤设置。

int ulog_tag_lvl_filter_set(const char *tag, rt_uint32_t level)` 设置指定标签（tag）的日志级别过滤器。参数 `tag` 是要设置过滤级别的标签，`level` 是要设置的日志级别。函数返回一个整数值，表示设置是否成功。

rt_uint32_t ulog_tag_lvl_filter_get(const char *tag)` 获取指定标签（tag）的日志级别过滤器配置。参数 `tag` 是要获取配置的标签。函数返回一个无符号 32 位整数，表示该标签的日志级别过滤器配置。

rt_slist_t *ulog_tag_lvl_list_get(void)` 获取所有日志标签和级别的链表。函数返回一个单项链表，该链表的每个节点包含一个日志标签（tag）和对应的日志级别。

void ulog_global_filter_lvl_set(rt_uint32_t level)` 设置全局日志级别过滤器的级别。参数 level 是要设置的全局日志级别。该过滤器将应用于所有日志输出，如果日志级别低于该设置的级别，则不会输出。 

rt_uint32_t ulog_global_filter_lvl_get(void)` 获取全局日志级别过滤器的级别。函数返回一个无符号 32 位整数，表示全局日志级别过滤器的配置。

void ulog_global_filter_tag_set(const char *tag)` 设置全局日志标签过滤器。参数 `tag` 是要设置的全局日志标签。只有匹配该标签的日志才会输出。

const char *ulog_global_filter_tag_get(void)` 获取全局日志标签过滤器的配置。函数返回一个字符串，表示全局日志标签过滤器的配置。

void ulog_global_filter_kw_set(const char *keyword)` 设置全局日志关键字过滤器。参数 `keyword` 是要设置的全局日志关键字。只有包含该关键字的日志信息才会输出。

const char *ulog_global_filter_kw_get(void)` 获取全局日志关键字过滤器的配置。函数返回一个字符串，表示全局日志关键字过滤器的配置。

这些函数的具体实现需要根据代码中的其他部分来确定。通过使用这些函数，可以在运行时动态配置日志过滤器，控制哪些日志信息应该被输出。这为日志输出提供了更加灵活的配置能力。需要注意的是，这些函数只有在条件编译宏 `ULOG_USING_FILTER` 被定义时才会生效。

ulog.c工作流程

39-69：设置不一样的info颜色

70： 规定最大log line buffer长度

73-109：rt_ulog {创建一个ulog本地对象，表示日志记录系统，包括输出互斥锁，存储后端信息的链表，异步输出设置，过滤器设置tag|keyword、level}

111-136：分配输出信息颜色

142-203：设置互斥锁保证输出日志的互斥访问；（？？？）

249-302：格式化日志输出的函数ulog_formater，其中主要包括日志缓冲区、级别、日志、日志标签tag、是否换行newline，格式化字符串format和参数列表arge；同时添加日志时间，主要是gettimeofday获取时间，通过rt_snprintf函数将格式化后的时间字符串写入日志缓冲区。

336-393：添加日志标签和线程信息（这里包含对中断日志的处理）：主要就是首先考虑当前是否在中断上下文中，如果不在中断上下文中，就先获取当前线程名称，然后拷贝到日志缓冲区中，如果当前在中断上下文中，就先将ISR字符串拷贝到日志缓冲区中，然后使用rt_vsnprintf函数将格式化后的日志消息写入日志缓冲区，计算日志长度加上格式化结果不超过ULOG_LINE_BUF_SIZE，若日志过长，则将日志长度设置为ULOG_LINE_BUF_SIZE，溢出时，也需要先CSI结束符、换行符和字符串结束符预留一些空间。如果使用颜色输出，且日志长度加上CSI结束符、换行符和字符串结束符的长度超过ULOG_LINE_BUF_SIZE，则将日志长度设置为ULOG_LINE_BUF_SIZE，并为CSI结束符预留一些空间。

426-483：将日志输出到所有后端的函数和执行日志输出的函数。ulog_output_to_all_backend输出到所有后端（先判断是否ulog已经初始化，然后检查后端，匹配输出级别，选择颜色，判断后端的过滤器函数，否则重新计算日志输出的起始地址和长度。首先计算颜色信息的长度，然后根据颜色信息的长度确定新的日志起始地址和日志长度，去除颜色输出的标记后，再调用后端的输出函数），输出函数ulog_output_to_all_backend相关参数主要包括：日志级别，标签，是否为原始日志，缓冲区，长度。

558-617：格式化并输出日志消息，同时处理了递归调用和日志过滤的情况，并通过调用相应的函数将消息输出到所有已注册的日志后端。格式化并输出日志消息，包括日志级别、标签、是否添加换行符、日志消息的格式字符串。函数执行逻辑：检查日志级别和标签是否满足过滤条件，调用get_log_buf获取一个缓冲区 锁定日志输出，防止并发访问冲突，使用 rt_vsnprintf 函数将格式化后的消息从可变参数列表 args 填充到日志缓冲区中。调用 ulog_output_to_all_backend 函数将日志缓冲区中的内容输出到所有已注册的日志后端。解锁日志输出。

660-720：ulog_output 函数用于格式化并输出日志消息。它接受日志级别 level、日志标签 tag、是否换行 newline、以及格式化字符串 format 和可变参数列表 args。ulog_raw 函数用于以原始形式输出日志消息，不进行格式化。它接受一个格式化字符串 format 和可变参数列表 args。这两个函数的作用是提供了不同的方式来输出日志消息。ulog_output 函数进行格式化输出而 ulog_raw 函数直接输出原始日志消息。它们都使用可变参数列表来接收日志消息的参数，可以根据需要输出不同级别和格式的日志信息。

730-874：hexdump函数用于以十六进制形式输出数据的转储。它接受日志标签 tag、每行显示的字节数 width、待转储数据的起始地址 buf，以及待转储数据的大小 size。日志输出中添加时间戳信息，方便记录日志的时间信息。同时，它也展示了根据编译选项的不同，如何选择不同的时间戳格式。

889-910：遍历 ulog.backend_list 链表（即所有注册的日志后端），找到与输入名称相匹配的后端，然后设置其输出级别为指定的值。通过这种方式，可以动态地控制每个日志后端的输出级别，以便过滤和管理日志的输出。最后，返回函数执行结果。

934-997：通过遍历已注册的标签级别过滤器链表，根据输入的标签和级别来进行添加、更新或移除标签级别过滤器的操作。通过设置标签级别过滤器，可以动态地控制特定标签的日志输出级别。最后，返回函数执行结果

1010-1070：提供获取指定标签的日志级别过滤器配置、获取全局日志过滤器级别、设置全局日志过滤器级别的功能。通过这些功能，可以动态地控制特定标签的日志输出级别，并设置全局的日志输出级别。

1078-1137：提供了设置和获取全局日志过滤器标签和关键字的功能，并提供一个用于调试输出日志级别信息的函数。通过这些功能，可以灵活地配置和获取全局日志过滤器的标签和关键字，并调试输出不同日志级别的相关信息。

函数 ulog_global_filter_tag_set 用于设置全局日志过滤器的标签。

函数 ulog_global_filter_tag_get 用于获取全局日志过滤器的标签

函数 ulog_global_filter_kw_set 用于设置全局日志过滤器的关键字

函数 ulog_global_filter_kw_get 用于获取全局日志过滤器的关键字

函数 _print_lvl_info 是一个用于调试输出的函数，用于打印不同日志级别的相关信息。

1140-1201：三个函数 ulog_be_lvl、ulog_tag_lvl 和 ulog_lvl，它们是用于设置日志过滤器级别的命令函数，并通过 MSH_CMD_EXPORT 宏将这些函数导出为命令行命令

函数 ulog_be_lvl 用于设置指定后端（backend）的日志过滤器级别

函数 ulog_tag_lvl 用于设置指定标签（tag）的日志过滤器级别

函数 ulog_lvl 用于设置全局日志过滤器级别

1255-1317：注册日志输出后端ulog_backend_register：调用该函数，可以将自定义的日志输出后端注册到 ulog 中，以便在日志输出时使用该后端进行实际的输出操作。

1320-1371：实现已注册的日志输出后端的注销、过滤器设置和查找操作，以便进行相应的管理和控制
ulog_backend_unregister 函数用于注销一个已注册的日志输出后端

ulog_backend_set_filter 函数用于设置日志输出后端的过滤器。

ulog_backend_find 函数用于根据名称查找已注册的日志输出后端。

1374-1424：可以实现日志的异步输出，从而提高系统的响应性能。异步输出模式下，日志会先存储在缓冲区中，然后在适当的时机进行输出，而不会阻塞当前线程的执行。

1434-1503：日志输出的刷新与初始化；

ulog_flush 函数用于刷新所有后端的日志。

ulog_init 函数用于初始化 ulog。

1506-1570：实现了 ulog 的初始化、异步输出的初始化和反初始化操作。

/*
 * Copyright (c) 2006-2022, RT-Thread Development Team
 *
 * SPDX-License-Identifier: Apache-2.0
 *
 * Change Logs:
 * Date           Author       Notes
 * 2018-08-25     armink       the first version
 */

#ifndef _ULOG_H_
#define _ULOG_H_

#include 
#include "ulog_def.h"

#ifdef __cplusplus
extern "C" {
#endif

/*
 * ulog init and deint
 */
int ulog_init(void);
int ulog_async_init(void);
void ulog_output_lock_enabled(rt_bool_t enabled);
void ulog_deinit(void);

/*
 * output different level log by LOG_X API
 *
 * NOTE: The `LOG_TAG` and `LOG_LVL` must be defined before including the  when you want to use LOG_X API.
 *
 * #define LOG_TAG              "example"
 * #define LOG_LVL              LOG_LVL_DBG
 * #include 
 *
 * Then you can using LOG_X API to output log
 *
 * LOG_D("this is a debug log!");
 * LOG_E("this is a error log!");
 */
#define LOG_E(...)                      ulog_e(LOG_TAG, __VA_ARGS__)
#define LOG_W(...)                      ulog_w(LOG_TAG, __VA_ARGS__)
#define LOG_I(...)                      ulog_i(LOG_TAG, __VA_ARGS__)
#define LOG_D(...)                      ulog_d(LOG_TAG, __VA_ARGS__)
#define LOG_RAW(...)                    ulog_raw(__VA_ARGS__)
#define LOG_HEX(name, width, buf, size) ulog_hex(name, width, buf, size)

/*
 * backend register and unregister
 */
rt_err_t ulog_backend_register(ulog_backend_t backend, const char *name, rt_bool_t support_color);
rt_err_t ulog_backend_unregister(ulog_backend_t backend);
rt_err_t ulog_backend_set_filter(ulog_backend_t backend, ulog_backend_filter_t filter);
ulog_backend_t ulog_backend_find(const char *name);

#ifdef ULOG_USING_FILTER
/*
 * log filter setting
 */
int ulog_tag_lvl_filter_set(const char *tag, rt_uint32_t level);
rt_uint32_t ulog_tag_lvl_filter_get(const char *tag);
rt_slist_t *ulog_tag_lvl_list_get(void);
void ulog_global_filter_lvl_set(rt_uint32_t level);
rt_uint32_t ulog_global_filter_lvl_get(void);
void ulog_global_filter_tag_set(const char *tag);
const char *ulog_global_filter_tag_get(void);
void ulog_global_filter_kw_set(const char *keyword);
const char *ulog_global_filter_kw_get(void);
#endif /* ULOG_USING_FILTER */

/*
 * flush all backends's log
 */
void ulog_flush(void);

#ifdef ULOG_USING_ASYNC_OUTPUT
/*
 * asynchronous output API
 */
void ulog_async_output(void);
void ulog_async_output_enabled(rt_bool_t enabled);
rt_err_t ulog_async_waiting_log(rt_int32_t time);
#endif

/*
 * dump the hex format data to log
 */
void ulog_hexdump(const char *tag, rt_size_t width, rt_uint8_t *buf, rt_size_t size);

/*
 * Another log output API. This API is more difficult to use than LOG_X API.
 */
void ulog_voutput(rt_uint32_t level, const char *tag, rt_bool_t newline, const char *format, va_list args);
void ulog_output(rt_uint32_t level, const char *tag, rt_bool_t newline, const char *format, ...);
void ulog_raw(const char *format, ...);

#ifdef __cplusplus
}
#endif

#endif /* _ULOG_H_ */

/*
 * Copyright (c) 2006-2022, RT-Thread Development Team
 *
 * SPDX-License-Identifier: Apache-2.0
 *
 * Change Logs:
 * Date           Author       Notes
 * 2018-08-25     armink       the first version
 */

#include 
#include "ulog.h"
#include "rthw.h"

#ifdef ULOG_USING_SYSLOG
#include 
#endif

#ifdef ULOG_TIME_USING_TIMESTAMP
#include 
#endif

#ifdef ULOG_USING_ASYNC_OUTPUT
#include 
#endif

#ifdef RT_USING_ULOG

/* the number which is max stored line logs */
#ifndef ULOG_ASYNC_OUTPUT_STORE_LINES
#define ULOG_ASYNC_OUTPUT_STORE_LINES  (ULOG_ASYNC_OUTPUT_BUF_SIZE * 3 / 2 / 80)
#endif

#ifdef ULOG_USING_COLOR
/**
 * CSI(Control Sequence Introducer/Initiator) sign
 * more information on https://en.wikipedia.org/wiki/ANSI_escape_code
 */
#define CSI_START                      "\033["
#define CSI_END                        "\033[0m"
/* output log front color */
#define F_BLACK                        "30m"
#define F_RED                          "31m"
#define F_GREEN                        "32m"
#define F_YELLOW                       "33m"
#define F_BLUE                         "34m"
#define F_MAGENTA                      "35m"
#define F_CYAN                         "36m"
#define F_WHITE                        "37m"

/* output log default color definition */
#ifndef ULOG_COLOR_DEBUG
#define ULOG_COLOR_DEBUG               RT_NULL
#endif
#ifndef ULOG_COLOR_INFO
#define ULOG_COLOR_INFO                (F_GREEN)
#endif
#ifndef ULOG_COLOR_WARN
#define ULOG_COLOR_WARN                (F_YELLOW)
#endif
#ifndef ULOG_COLOR_ERROR
#define ULOG_COLOR_ERROR               (F_RED)
#endif
#ifndef ULOG_COLOR_ASSERT
#define ULOG_COLOR_ASSERT              (F_MAGENTA)
#endif
#endif /* ULOG_USING_COLOR */

#if ULOG_LINE_BUF_SIZE < 80
#error "the log line buffer size must more than 80"
#endif

struct rt_ulog
{
    rt_bool_t init_ok;
    rt_bool_t output_lock_enabled;
    struct rt_mutex output_locker;
    /* all backends */
    rt_slist_t backend_list;
    /* the thread log's line buffer */
    char log_buf_th[ULOG_LINE_BUF_SIZE + 1];

#ifdef ULOG_USING_ISR_LOG
    /* the ISR log's line buffer */
    rt_base_t output_locker_isr_lvl;
    char log_buf_isr[ULOG_LINE_BUF_SIZE + 1];
#endif /* ULOG_USING_ISR_LOG */

#ifdef ULOG_USING_ASYNC_OUTPUT
    rt_bool_t async_enabled;
    rt_rbb_t async_rbb;
    /* ringbuffer for log_raw function only */
    struct rt_ringbuffer *async_rb;
    rt_thread_t async_th;
    struct rt_semaphore async_notice;
#endif

#ifdef ULOG_USING_FILTER
    struct
    {
        /* all tag's level filter */
        rt_slist_t tag_lvl_list;
        /* global filter level, tag and keyword */
        rt_uint32_t level;
        char tag[ULOG_FILTER_TAG_MAX_LEN + 1];
        char keyword[ULOG_FILTER_KW_MAX_LEN + 1];
    } filter;
#endif /* ULOG_USING_FILTER */
};

/* level output info */
static const char * const level_output_info[] =
{
    "A/",
    RT_NULL,
    RT_NULL,
    "E/",
    "W/",
    RT_NULL,
    "I/",
    "D/",
};

#ifdef ULOG_USING_COLOR
/* color output info */
static const char * const color_output_info[] =
{
    ULOG_COLOR_ASSERT,
    RT_NULL,
    RT_NULL,
    ULOG_COLOR_ERROR,
    ULOG_COLOR_WARN,
    RT_NULL,
    ULOG_COLOR_INFO,
    ULOG_COLOR_DEBUG,
};
#endif /* ULOG_USING_COLOR */

/* ulog local object */
static struct rt_ulog ulog = { 0 };

rt_size_t ulog_strcpy(rt_size_t cur_len, char *dst, const char *src)
{
    const char *src_old = src;

    RT_ASSERT(dst);
    RT_ASSERT(src);

    while (*src != 0)
    {
        /* make sure destination has enough space */
        if (cur_len++ < ULOG_LINE_BUF_SIZE)
        {
            *dst++ = *src++;
        }
        else
        {
            break;
        }
    }
    return src - src_old;
}

rt_size_t ulog_ultoa(char *s, unsigned long int n)
{
    rt_size_t i = 0, j = 0, len = 0;
    char swap;

    do
    {
        s[len++] = n % 10 + '0';
    } while (n /= 10);
    s[len] = '\0';
    /* reverse string */
    for (i = 0, j = len - 1; i < j; ++i, --j)
    {
        swap = s[i];
        s[i] = s[j];
        s[j] = swap;
    }
    return len;
}

static void output_unlock(void)
{
    /* earlier stage */
    if (ulog.output_lock_enabled == RT_FALSE)
    {
        return;
    }

    /* If the scheduler is started and in thread context */
    if (rt_interrupt_get_nest() == 0 && rt_thread_self() != RT_NULL)
    {
        rt_mutex_release(&ulog.output_locker);
    }
    else
    {
#ifdef ULOG_USING_ISR_LOG
        rt_hw_interrupt_enable(ulog.output_locker_isr_lvl);
#endif
    }
}

static void output_lock(void)
{
    /* earlier stage */
    if (ulog.output_lock_enabled == RT_FALSE)
    {
        return;
    }

    /* If the scheduler is started and in thread context */
    if (rt_interrupt_get_nest() == 0 && rt_thread_self() != RT_NULL)
    {
        rt_mutex_take(&ulog.output_locker, RT_WAITING_FOREVER);
    }
    else
    {
#ifdef ULOG_USING_ISR_LOG
        ulog.output_locker_isr_lvl = rt_hw_interrupt_disable();
#endif
    }
}

void ulog_output_lock_enabled(rt_bool_t enabled)
{
    ulog.output_lock_enabled = enabled;
}

static char *get_log_buf(void)
{
    /* is in thread context */
    if (rt_interrupt_get_nest() == 0)
    {
        return ulog.log_buf_th;
    }
    else
    {
#ifdef ULOG_USING_ISR_LOG
        return ulog.log_buf_isr;
#else
        rt_kprintf("Error: Current mode not supported run in ISR. Please enable ULOG_USING_ISR_LOG.\n");
        return RT_NULL;
#endif
    }
}

RT_WEAK rt_size_t ulog_formater(char *log_buf, rt_uint32_t level, const char *tag, rt_bool_t newline,
        const char *format, va_list args)
{
    /* the caller has locker, so it can use static variable for reduce stack usage */
    static rt_size_t log_len, newline_len;
    static int fmt_result;

    RT_ASSERT(log_buf);
    RT_ASSERT(level <= LOG_LVL_DBG);
    RT_ASSERT(tag);
    RT_ASSERT(format);

    log_len = 0;
    newline_len = rt_strlen(ULOG_NEWLINE_SIGN);

#ifdef ULOG_USING_COLOR
    /* add CSI start sign and color info */
    if (color_output_info[level])
    {
        log_len += ulog_strcpy(log_len, log_buf + log_len, CSI_START);
        log_len += ulog_strcpy(log_len, log_buf + log_len, color_output_info[level]);
    }
#endif /* ULOG_USING_COLOR */

    log_buf[log_len] = '\0';

#ifdef ULOG_OUTPUT_TIME
    /* add time info */
    {
#ifdef ULOG_TIME_USING_TIMESTAMP
        static struct timeval now;
        static struct tm *tm, tm_tmp;
        static rt_bool_t check_usec_support = RT_FALSE, usec_is_support = RT_FALSE;
        time_t t = (time_t)0;

        if (gettimeofday(&now, RT_NULL) >= 0)
        {
            t = now.tv_sec;
        }
        tm = localtime_r(&t, &tm_tmp);
        /* show the time format MM-DD HH:MM:SS */
        rt_snprintf(log_buf + log_len, ULOG_LINE_BUF_SIZE - log_len, "%02d-%02d %02d:%02d:%02d", tm->tm_mon + 1,
                tm->tm_mday, tm->tm_hour, tm->tm_min, tm->tm_sec);
        /* check the microseconds support when kernel is startup */
        if (t > 0 && !check_usec_support && rt_thread_self() != RT_NULL)
        {
            long old_usec = now.tv_usec;
            /* delay some time for wait microseconds changed */
            rt_thread_mdelay(10);
            gettimeofday(&now, RT_NULL);
            check_usec_support = RT_TRUE;
            /* the microseconds is not equal between two gettimeofday calls */
            if (now.tv_usec != old_usec)
                usec_is_support = RT_TRUE;
        }
        if (usec_is_support)
        {
            /* show the millisecond */
            log_len += rt_strlen(log_buf + log_len);
            rt_snprintf(log_buf + log_len, ULOG_LINE_BUF_SIZE - log_len, ".%03d", now.tv_usec / 1000);
        }

#else
        static rt_size_t tick_len = 0;

        log_buf[log_len] = '[';
        tick_len = ulog_ultoa(log_buf + log_len + 1, rt_tick_get());
        log_buf[log_len + 1 + tick_len] = ']';
        log_buf[log_len + 1 + tick_len + 1] = '\0';
#endif /* ULOG_TIME_USING_TIMESTAMP */

        log_len += rt_strlen(log_buf + log_len);
    }
#endif /* ULOG_OUTPUT_TIME */

#ifdef ULOG_OUTPUT_LEVEL

#ifdef ULOG_OUTPUT_TIME
    log_len += ulog_strcpy(log_len, log_buf + log_len, " ");
#endif

    /* add level info */
    log_len += ulog_strcpy(log_len, log_buf + log_len, level_output_info[level]);
#endif /* ULOG_OUTPUT_LEVEL */

#ifdef ULOG_OUTPUT_TAG

#if !defined(ULOG_OUTPUT_LEVEL) && defined(ULOG_OUTPUT_TIME)
    log_len += ulog_strcpy(log_len, log_buf + log_len, " ");
#endif

    /* add tag info */
    log_len += ulog_strcpy(log_len, log_buf + log_len, tag);
#endif /* ULOG_OUTPUT_TAG */

#ifdef ULOG_OUTPUT_THREAD_NAME
    /* add thread info */
    {

#if defined(ULOG_OUTPUT_TIME) || defined(ULOG_OUTPUT_LEVEL) || defined(ULOG_OUTPUT_TAG)
        log_len += ulog_strcpy(log_len, log_buf + log_len, " ");
#endif

        /* is not in interrupt context */
        if (rt_interrupt_get_nest() == 0)
        {
            rt_size_t name_len = 0;
            const char *thread_name = "N/A";
            if (rt_thread_self())
            {
                thread_name = rt_thread_self()->name;
            }
            name_len = rt_strnlen(thread_name, RT_NAME_MAX);
            rt_strncpy(log_buf + log_len, thread_name, name_len);
            log_len += name_len;
        }
        else
        {
            log_len += ulog_strcpy(log_len, log_buf + log_len, "ISR");
        }
    }
#endif /* ULOG_OUTPUT_THREAD_NAME */

    log_len += ulog_strcpy(log_len, log_buf + log_len, ": ");
    fmt_result = rt_vsnprintf(log_buf + log_len, ULOG_LINE_BUF_SIZE - log_len, format, args);

    /* calculate log length */
    if ((log_len + fmt_result <= ULOG_LINE_BUF_SIZE) && (fmt_result > -1))
    {
        log_len += fmt_result;
    }
    else
    {
        /* using max length */
        log_len = ULOG_LINE_BUF_SIZE;
    }

    /* overflow check and reserve some space for CSI end sign, newline sign and string end sign */
#ifdef ULOG_USING_COLOR
    if (log_len + (sizeof(CSI_END) - 1) + newline_len + sizeof((char)'\0') > ULOG_LINE_BUF_SIZE)
    {
        /* using max length */
        log_len = ULOG_LINE_BUF_SIZE;
        /* reserve some space for CSI end sign */
        log_len -= (sizeof(CSI_END) - 1);
#else
    if (log_len + newline_len + sizeof((char)'\0') > ULOG_LINE_BUF_SIZE)
    {
        /* using max length */
        log_len = ULOG_LINE_BUF_SIZE;
#endif /* ULOG_USING_COLOR */
        /* reserve some space for newline sign */
        log_len -= newline_len;
        /* reserve some space for string end sign */
        log_len -= sizeof((char)'\0');
    }

    /* package newline sign */
    if (newline)
    {
        log_len += ulog_strcpy(log_len, log_buf + log_len, ULOG_NEWLINE_SIGN);
    }

#ifdef ULOG_USING_COLOR
    /* add CSI end sign  */
    if (color_output_info[level])
    {
        log_len += ulog_strcpy(log_len, log_buf + log_len, CSI_END);
    }
#endif /* ULOG_USING_COLOR */

    /* add string end sign */
    log_buf[log_len] = '\0';

    return log_len;
}

static void ulog_output_to_all_backend(rt_uint32_t level, const char *tag, rt_bool_t is_raw, const char *log, rt_size_t len)
{
    rt_slist_t *node;
    ulog_backend_t backend;

    if (!ulog.init_ok)
        return;

    /* if there is no backend */
    if (!rt_slist_first(&ulog.backend_list))
    {
        rt_kputs(log);
        return;
    }

    /* output for all backends */
    for (node = rt_slist_first(&ulog.backend_list); node; node = rt_slist_next(node))
    {
        backend = rt_slist_entry(node, struct ulog_backend, list);
        if (backend->out_level < level)
        {
            continue;
        }
#if !defined(ULOG_USING_COLOR) || defined(ULOG_USING_SYSLOG)
        backend->output(backend, level, tag, is_raw, log, len);
#else
        if (backend->filter && backend->filter(backend, level, tag, is_raw, log, len) == RT_FALSE)
        {
            /* backend's filter is not match, so skip output */
            continue;
        }
        if (backend->support_color || is_raw)
        {
            backend->output(backend, level, tag, is_raw, log, len);
        }
        else
        {
            /* recalculate the log start address and log size when backend not supported color */
            rt_size_t color_info_len = 0, output_len = len;
            const char *output_log = log;

            if (color_output_info[level] != RT_NULL)
                color_info_len = rt_strlen(color_output_info[level]);

            if (color_info_len)
            {
                rt_size_t color_hdr_len = rt_strlen(CSI_START) + color_info_len;

                output_log += color_hdr_len;
                output_len -= (color_hdr_len + (sizeof(CSI_END) - 1));
            }
            backend->output(backend, level, tag, is_raw, output_log, output_len);
        }
#endif /* !defined(ULOG_USING_COLOR) || defined(ULOG_USING_SYSLOG) */
    }
}

static void do_output(rt_uint32_t level, const char *tag, rt_bool_t is_raw, const char *log_buf, rt_size_t log_len)
{
#ifdef ULOG_USING_ASYNC_OUTPUT
    rt_size_t log_buf_size = log_len + sizeof((char)'\0');

    if (is_raw == RT_FALSE)
    {
        rt_rbb_blk_t log_blk;
        ulog_frame_t log_frame;

        /* allocate log frame */
        log_blk = rt_rbb_blk_alloc(ulog.async_rbb, RT_ALIGN(sizeof(struct ulog_frame) + log_buf_size, RT_ALIGN_SIZE));
        if (log_blk)
        {
            /* package the log frame */
            log_frame = (ulog_frame_t) log_blk->buf;
            log_frame->magic = ULOG_FRAME_MAGIC;
            log_frame->is_raw = is_raw;
            log_frame->level = level;
            log_frame->log_len = log_len;
            log_frame->tag = tag;
            log_frame->log = (const char *)log_blk->buf + sizeof(struct ulog_frame);
            /* copy log data */
            rt_strncpy((char *)(log_blk->buf + sizeof(struct ulog_frame)), log_buf, log_buf_size);
            /* put the block */
            rt_rbb_blk_put(log_blk);
            /* send a notice */
            rt_sem_release(&ulog.async_notice);
        }
        else
        {
            static rt_bool_t already_output = RT_FALSE;
            if (already_output == RT_FALSE)
            {
                rt_kprintf("Warning: There is no enough buffer for saving async log,"
                        " please increase the ULOG_ASYNC_OUTPUT_BUF_SIZE option.\n");
                already_output = RT_TRUE;
            }
        }
    }
    else if (ulog.async_rb)
    {
        rt_ringbuffer_put(ulog.async_rb, (const rt_uint8_t *)log_buf, log_buf_size);
        /* send a notice */
        rt_sem_release(&ulog.async_notice);
    }
#else
    /* is in thread context */
    if (rt_interrupt_get_nest() == 0)
    {
        /* output to all backends */
        ulog_output_to_all_backend(level, tag, is_raw, log_buf, log_len);
    }
    else
    {
#ifdef ULOG_BACKEND_USING_CONSOLE
        /* We can't ensure that all backends support ISR context output.
         * So only using rt_kprintf when context is ISR */
        extern void ulog_console_backend_output(struct ulog_backend *backend, rt_uint32_t level, const char *tag,
                rt_bool_t is_raw, const char *log, rt_size_t len);
        ulog_console_backend_output(RT_NULL, level, tag, is_raw, log_buf, log_len);
#endif /* ULOG_BACKEND_USING_CONSOLE */
    }
#endif /* ULOG_USING_ASYNC_OUTPUT */
}

/**
 * output the log by variable argument list
 *
 * @param level level
 * @param tag tag
 * @param newline has_newline
 * @param format output format
 * @param args variable argument list
 */
void ulog_voutput(rt_uint32_t level, const char *tag, rt_bool_t newline, const char *format, va_list args)
{
    static rt_bool_t ulog_voutput_recursion = RT_FALSE;
    char *log_buf = RT_NULL;
    rt_size_t log_len = 0;

    RT_ASSERT(tag);
    RT_ASSERT(format);
#ifndef ULOG_USING_SYSLOG
    RT_ASSERT(level <= LOG_LVL_DBG);
#else
    RT_ASSERT(LOG_PRI(level) <= LOG_DEBUG);
#endif /* ULOG_USING_SYSLOG */


    if (!ulog.init_ok)
    {
        return;
    }

#ifdef ULOG_USING_FILTER
    /* level filter */
#ifndef ULOG_USING_SYSLOG
    if (level > ulog.filter.level || level > ulog_tag_lvl_filter_get(tag))
    {
        return;
    }
#else
    if (((LOG_MASK(LOG_PRI(level)) & ulog.filter.level) == 0)
            || ((LOG_MASK(LOG_PRI(level)) & ulog_tag_lvl_filter_get(tag)) == 0))
    {
        return;
    }
#endif /* ULOG_USING_SYSLOG */
    else if (!rt_strstr(tag, ulog.filter.tag))
    {
        /* tag filter */
        return;
    }
#endif /* ULOG_USING_FILTER */

    /* get log buffer */
    log_buf = get_log_buf();

    /* lock output */
    output_lock();

    /* If there is a recursion, we use a simple way */
    if (ulog_voutput_recursion == RT_TRUE)
    {
        rt_kprintf(format, args);
        if(newline == RT_TRUE)
        {
            rt_kprintf(ULOG_NEWLINE_SIGN);
        }
        output_unlock();
        return;
    }

    ulog_voutput_recursion = RT_TRUE;

#ifndef ULOG_USING_SYSLOG
    log_len = ulog_formater(log_buf, level, tag, newline, format, args);
#else
    extern rt_size_t syslog_formater(char *log_buf, rt_uint8_t level, const char *tag, rt_bool_t newline, const char *format, va_list args);
    log_len = syslog_formater(log_buf, level, tag, newline, format, args);
#endif /* ULOG_USING_SYSLOG */

#ifdef ULOG_USING_FILTER
    /* keyword filter */
    if (ulog.filter.keyword[0] != '\0')
    {
        /* add string end sign */
        log_buf[log_len] = '\0';
        /* find the keyword */
        if (!rt_strstr(log_buf, ulog.filter.keyword))
        {
            ulog_voutput_recursion = RT_FALSE;
            /* unlock output */
            output_unlock();
            return;
        }
    }
#endif /* ULOG_USING_FILTER */
    /* do log output */
    do_output(level, tag, RT_FALSE, log_buf, log_len);

    ulog_voutput_recursion = RT_FALSE;

    /* unlock output */
    output_unlock();
}

/**
 * output the log
 *
 * @param level level
 * @param tag tag
 * @param newline has newline
 * @param format output format
 * @param ... args
 */
void ulog_output(rt_uint32_t level, const char *tag, rt_bool_t newline, const char *format, ...)
{
    va_list args;

    /* args point to the first variable parameter */
    va_start(args, format);

    ulog_voutput(level, tag, newline, format, args);

    va_end(args);
}

/**
 * output RAW string format log
 *
 * @param format output format
 * @param ... args
 */
void ulog_raw(const char *format, ...)
{
    rt_size_t log_len = 0;
    char *log_buf = RT_NULL;
    va_list args;
    int fmt_result;

    RT_ASSERT(ulog.init_ok);

#ifdef ULOG_USING_ASYNC_OUTPUT
    if (ulog.async_rb == RT_NULL)
    {
        ulog.async_rb = rt_ringbuffer_create(ULOG_ASYNC_OUTPUT_BUF_SIZE);
    }
#endif

    /* get log buffer */
    log_buf = get_log_buf();

    /* lock output */
    output_lock();

    /* args point to the first variable parameter */
    va_start(args, format);
    fmt_result = rt_vsnprintf(log_buf, ULOG_LINE_BUF_SIZE, format, args);
    va_end(args);

    /* calculate log length */
    if ((fmt_result > -1) && (fmt_result <= ULOG_LINE_BUF_SIZE))
    {
        log_len = fmt_result;
    }
    else
    {
        log_len = ULOG_LINE_BUF_SIZE;
    }

    /* do log output */
    do_output(LOG_LVL_DBG, "", RT_TRUE, log_buf, log_len);

    /* unlock output */
    output_unlock();
}

/**
 * dump the hex format data to log
 *
 * @param tag name for hex object, it will show on log header
 * @param width hex number for every line, such as: 16, 32
 * @param buf hex buffer
 * @param size buffer size
 */
void ulog_hexdump(const char *tag, rt_size_t width, rt_uint8_t *buf, rt_size_t size)
{
#define __is_print(ch)       ((unsigned int)((ch) - ' ') < 127u - ' ')

    rt_size_t i, j;
    rt_size_t log_len = 0, name_len = rt_strlen(tag);
#ifdef ULOG_OUTPUT_TIME
    rt_size_t time_head_len = 0;
#endif
    char *log_buf = RT_NULL, dump_string[8];
    int fmt_result;

    RT_ASSERT(ulog.init_ok);

#ifdef ULOG_USING_FILTER
    /* level filter */
#ifndef ULOG_USING_SYSLOG
    if (LOG_LVL_DBG > ulog.filter.level || LOG_LVL_DBG > ulog_tag_lvl_filter_get(tag))
    {
        return;
    }
#else
    if ((LOG_MASK(LOG_DEBUG) & ulog.filter.level) == 0)
    {
        return;
    }
#endif /* ULOG_USING_SYSLOG */
    else if (!rt_strstr(tag, ulog.filter.tag))
    {
        /* tag filter */
        return;
    }
#endif /* ULOG_USING_FILTER */

#ifdef ULOG_USING_ASYNC_OUTPUT
    if (ulog.async_rb == RT_NULL)
    {
        ulog.async_rb = rt_ringbuffer_create(ULOG_ASYNC_OUTPUT_BUF_SIZE);
    }
#endif

    /* get log buffer */
    log_buf = get_log_buf();

    /* lock output */
    output_lock();

    for (i = 0, log_len = 0; i < size; i += width)
    {
        /* package header */
        if (i == 0)
        {
#ifdef ULOG_OUTPUT_TIME
            /* add time info */
#ifdef ULOG_TIME_USING_TIMESTAMP
            static time_t now;
            static struct tm *tm, tm_tmp;

            now = time(RT_NULL);
            tm = gmtime_r(&now, &tm_tmp);

#ifdef RT_USING_SOFT_RTC
            rt_snprintf(log_buf + log_len, ULOG_LINE_BUF_SIZE - log_len, "%02d-%02d %02d:%02d:%02d.%03d ", tm->tm_mon + 1,
                tm->tm_mday, tm->tm_hour, tm->tm_min, tm->tm_sec, rt_tick_get() % 1000);
#else
            rt_snprintf(log_buf + log_len, ULOG_LINE_BUF_SIZE - log_len, "%02d-%02d %02d:%02d:%02d ", tm->tm_mon + 1,
                tm->tm_mday, tm->tm_hour, tm->tm_min, tm->tm_sec);
#endif /* RT_USING_SOFT_RTC */

#else
            static rt_size_t tick_len = 0;

            log_buf[log_len] = '[';
            tick_len = ulog_ultoa(log_buf + log_len + 1, rt_tick_get());
            log_buf[log_len + 1 + tick_len] = ']';
            log_buf[log_len + 2 + tick_len] = ' ';
            log_buf[log_len + 3 + tick_len] = '\0';
#endif /* ULOG_TIME_USING_TIMESTAMP */
            time_head_len = rt_strlen(log_buf + log_len);
            log_len += time_head_len;
#endif /* ULOG_OUTPUT_TIME */
            log_len += ulog_strcpy(log_len, log_buf + log_len, "D/HEX ");
            log_len += ulog_strcpy(log_len, log_buf + log_len, tag);
            log_len += ulog_strcpy(log_len, log_buf + log_len, ": ");
        }
        else
        {
            log_len = 6 + name_len + 2;
#ifdef ULOG_OUTPUT_TIME
            log_len += time_head_len;
#endif
            rt_memset(log_buf, ' ', log_len);
        }
        fmt_result = rt_snprintf(log_buf + log_len, ULOG_LINE_BUF_SIZE, "%04X-%04X: ", i, i + width - 1);
        /* calculate log length */
        if ((fmt_result > -1) && (fmt_result <= ULOG_LINE_BUF_SIZE))
        {
            log_len += fmt_result;
        }
        else
        {
            log_len = ULOG_LINE_BUF_SIZE;
        }
        /* dump hex */
        for (j = 0; j < width; j++)
        {
            if (i + j < size)
            {
                rt_snprintf(dump_string, sizeof(dump_string), "%02X ", buf[i + j]);
            }
            else
            {
                rt_strncpy(dump_string, "   ", sizeof(dump_string));
            }
            log_len += ulog_strcpy(log_len, log_buf + log_len, dump_string);
            if ((j + 1) % 8 == 0)
            {
                log_len += ulog_strcpy(log_len, log_buf + log_len, " ");
            }
        }
        log_len += ulog_strcpy(log_len, log_buf + log_len, "  ");
        /* dump char for hex */
        for (j = 0; j < width; j++)
        {
            if (i + j < size)
            {
                rt_snprintf(dump_string, sizeof(dump_string), "%c", __is_print(buf[i + j]) ? buf[i + j] : '.');
                log_len += ulog_strcpy(log_len, log_buf + log_len, dump_string);
            }
        }
        /* overflow check and reserve some space for newline sign */
        if (log_len + rt_strlen(ULOG_NEWLINE_SIGN) > ULOG_LINE_BUF_SIZE)
        {
            log_len = ULOG_LINE_BUF_SIZE - rt_strlen(ULOG_NEWLINE_SIGN);
        }
        /* package newline sign */
        log_len += ulog_strcpy(log_len, log_buf + log_len, ULOG_NEWLINE_SIGN);
        /*add string end sign*/
        log_buf[log_len] = '\0';
        /* do log output */
        do_output(LOG_LVL_DBG, RT_NULL, RT_TRUE, log_buf, log_len);
    }
    /* unlock output */
    output_unlock();
}

#ifdef ULOG_USING_FILTER
/**
 * Set the filter's level by different backend.
 * The log on this backend which level is less than it will stop output.
 *
 * @param be_name backend name
 * @param level The filter level. When the level is LOG_FILTER_LVL_SILENT, the log enter silent mode.
 *        When the level is LOG_FILTER_LVL_ALL, it will remove this tag's level filer.
 *        Then all level log will resume output.
 *
 * @return  0 : success
 *         -10: level is out of range
 */
int ulog_be_lvl_filter_set(const char *be_name, rt_uint32_t level)
{
    rt_slist_t *node = RT_NULL;
    ulog_backend_t backend;
    int result = RT_EOK;

    if (level > LOG_FILTER_LVL_ALL)
        return -RT_EINVAL;

    if (!ulog.init_ok)
        return result;

    for (node = rt_slist_first(&ulog.backend_list); node; node = rt_slist_next(node))
    {
        backend = rt_slist_entry(node, struct ulog_backend, list);
        if (rt_strncmp(backend->name, be_name, RT_NAME_MAX) == 0)
        {
            backend->out_level = level;
        }
    }

    return result;
}

/**
 * Set the filter's level by different tag.
 * The log on this tag which level is less than it will stop output.
 *
 * example:
 *     // the example tag log enter silent mode
 *     ulog_set_filter_lvl("example", LOG_FILTER_LVL_SILENT);
 *     // the example tag log which level is less than INFO level will stop output
 *     ulog_set_filter_lvl("example", LOG_LVL_INFO);
 *     // remove example tag's level filter, all level log will resume output
 *     ulog_set_filter_lvl("example", LOG_FILTER_LVL_ALL);
 *
 * @param tag log tag
 * @param level The filter level. When the level is LOG_FILTER_LVL_SILENT, the log enter silent mode.
 *        When the level is LOG_FILTER_LVL_ALL, it will remove this tag's level filer.
 *        Then all level log will resume output.
 *
 * @return  0 : success
 *         -5 : no memory
 *         -10: level is out of range
 */
int ulog_tag_lvl_filter_set(const char *tag, rt_uint32_t level)
{
    rt_slist_t *node;
    ulog_tag_lvl_filter_t tag_lvl = RT_NULL;
    int result = RT_EOK;

    if (level > LOG_FILTER_LVL_ALL)
        return -RT_EINVAL;

    if (!ulog.init_ok)
        return result;

    /* lock output */
    output_lock();
    /* find the tag in list */
    for (node = rt_slist_first(ulog_tag_lvl_list_get()); node; node = rt_slist_next(node))
    {
        tag_lvl = rt_slist_entry(node, struct ulog_tag_lvl_filter, list);
        if (!rt_strncmp(tag_lvl->tag, tag, ULOG_FILTER_TAG_MAX_LEN))
        {
            break;
        }
        else
        {
            tag_lvl = RT_NULL;
        }
    }
    /* find OK */
    if (tag_lvl)
    {
        if (level == LOG_FILTER_LVL_ALL)
        {
            /* remove current tag's level filter when input level is the lowest level */
            rt_slist_remove(ulog_tag_lvl_list_get(), &tag_lvl->list);
            rt_free(tag_lvl);
        }
        else
        {
            /* update level */
            tag_lvl->level = level;
        }
    }
    else
    {
        /* only add the new tag's level filer when level is not LOG_FILTER_LVL_ALL */
        if (level != LOG_FILTER_LVL_ALL)
        {
            /* new a tag's level filter */
            tag_lvl = (ulog_tag_lvl_filter_t)rt_malloc(sizeof(struct ulog_tag_lvl_filter));
            if (tag_lvl)
            {
                rt_memset(tag_lvl->tag, 0 , sizeof(tag_lvl->tag));
                rt_strncpy(tag_lvl->tag, tag, ULOG_FILTER_TAG_MAX_LEN);
                tag_lvl->level = level;
                rt_slist_append(ulog_tag_lvl_list_get(), &tag_lvl->list);
            }
            else
            {
                result = -RT_ENOMEM;
            }
        }
    }
    /* unlock output */
    output_unlock();

    return result;
}

/**
 * get the level on tag's level filer
 *
 * @param tag log tag
 *
 * @return It will return the lowest level when tag was not found.
 *         Other level will return when tag was found.
 */
rt_uint32_t ulog_tag_lvl_filter_get(const char *tag)
{
    rt_slist_t *node;
    ulog_tag_lvl_filter_t tag_lvl = RT_NULL;
    rt_uint32_t level = LOG_FILTER_LVL_ALL;

    if (!ulog.init_ok)
        return level;

    /* lock output */
    output_lock();
    /* find the tag in list */
    for (node = rt_slist_first(ulog_tag_lvl_list_get()); node; node = rt_slist_next(node))
    {
        tag_lvl = rt_slist_entry(node, struct ulog_tag_lvl_filter, list);
        if (!rt_strncmp(tag_lvl->tag, tag, ULOG_FILTER_TAG_MAX_LEN))
        {
            level = tag_lvl->level;
            break;
        }
    }
    /* unlock output */
    output_unlock();

    return level;
}

/**
 * get the tag's level list on filter
 *
 * @return tag's level list
 */
rt_slist_t *ulog_tag_lvl_list_get(void)
{
    return &ulog.filter.tag_lvl_list;
}

/**
 * set log global filter level
 *
 * @param level log level: LOG_LVL_ASSERT, LOG_LVL_ERROR, LOG_LVL_WARNING, LOG_LVL_INFO, LOG_LVL_DBG
 *              LOG_FILTER_LVL_SILENT: disable all log output, except assert level
 *              LOG_FILTER_LVL_ALL: enable all log output
 */
void ulog_global_filter_lvl_set(rt_uint32_t level)
{
    RT_ASSERT(level <= LOG_FILTER_LVL_ALL);

    ulog.filter.level = level;
}

/**
 * get log global filter level
 *
 * @return log level: LOG_LVL_ASSERT, LOG_LVL_ERROR, LOG_LVL_WARNING, LOG_LVL_INFO, LOG_LVL_DBG
 *              LOG_FILTER_LVL_SILENT: disable all log output, except assert level
 *              LOG_FILTER_LVL_ALL: enable all log output
 */
rt_uint32_t ulog_global_filter_lvl_get(void)
{
    return ulog.filter.level;
}

/**
 * set log global filter tag
 *
 * @param tag tag
 */
void ulog_global_filter_tag_set(const char *tag)
{
    RT_ASSERT(tag);

    rt_strncpy(ulog.filter.tag, tag, ULOG_FILTER_TAG_MAX_LEN);
}

/**
 * get log global filter tag
 *
 * @return tag
 */
const char *ulog_global_filter_tag_get(void)
{
    return ulog.filter.tag;
}

/**
 * set log global filter keyword
 *
 * @param keyword keyword
 */
void ulog_global_filter_kw_set(const char *keyword)
{
    RT_ASSERT(keyword);

    rt_strncpy(ulog.filter.keyword, keyword, ULOG_FILTER_KW_MAX_LEN);
}

/**
 * get log global filter keyword
 *
 * @return keyword
 */
const char *ulog_global_filter_kw_get(void)
{
    return ulog.filter.keyword;
}

#ifdef RT_USING_FINSH
#include 

static void _print_lvl_info(void)
{
#ifndef ULOG_USING_SYSLOG
    rt_kprintf("Assert  : 0\n");
    rt_kprintf("Error   : 3\n");
    rt_kprintf("Warning : 4\n");
    rt_kprintf("Info    : 6\n");
    rt_kprintf("Debug   : 7\n");
#else
    rt_kprintf("EMERG   :   1 (1 << 0)\n");
    rt_kprintf("ALERT   :   2 (1 << 1)\n");
    rt_kprintf("CRIT    :   4 (1 << 2)\n");
    rt_kprintf("ERR     :   8 (1 << 3)\n");
    rt_kprintf("WARNING :  16 (1 << 4)\n");
    rt_kprintf("NOTICE  :  32 (1 << 5)\n");
    rt_kprintf("INFO    :  64 (1 << 6)\n");
    rt_kprintf("DEBUG   : 128 (1 << 7)\n");
#endif /* ULOG_USING_SYSLOG */
}

static void ulog_be_lvl(uint8_t argc, char **argv)
{
    if (argc > 2)
    {
        if ((atoi(argv[2]) <= LOG_FILTER_LVL_ALL) && (atoi(argv[2]) >= 0))
        {
            ulog_be_lvl_filter_set(argv[1], atoi(argv[2]));
        }
        else
        {
            rt_kprintf("Please input correct level (0-%d).\n", LOG_FILTER_LVL_ALL);
        }
    }
    else
    {
        rt_kprintf("Please input: ulog_be_lvl  .\n");
        _print_lvl_info();
    }
}
MSH_CMD_EXPORT(ulog_be_lvl, Set ulog filter level by different backend.);

static void ulog_tag_lvl(uint8_t argc, char **argv)
{
    if (argc > 2)
    {
        if ((atoi(argv[2]) <= LOG_FILTER_LVL_ALL) && (atoi(argv[2]) >= 0))
        {
            ulog_tag_lvl_filter_set(argv[1], atoi(argv[2]));
        }
        else
        {
            rt_kprintf("Please input correct level (0-%d).\n", LOG_FILTER_LVL_ALL);
        }
    }
    else
    {
        rt_kprintf("Please input: ulog_tag_lvl  .\n");
        _print_lvl_info();
    }
}
MSH_CMD_EXPORT(ulog_tag_lvl, Set ulog filter level by different tag.);

static void ulog_lvl(uint8_t argc, char **argv)
{
    if (argc > 1)
    {
        if ((atoi(argv[1]) <= LOG_FILTER_LVL_ALL) && (atoi(argv[1]) >= 0))
        {
            ulog_global_filter_lvl_set(atoi(argv[1]));
        }
        else
        {
            rt_kprintf("Please input correct level (0-%d).\n", LOG_FILTER_LVL_ALL);
        }
    }
    else
    {
        rt_kprintf("Please input: ulog_lvl .\n");
        _print_lvl_info();
    }
}
MSH_CMD_EXPORT(ulog_lvl, Set ulog global filter level.);

static void ulog_tag(uint8_t argc, char **argv)
{
    if (argc > 1)
    {
        if (rt_strlen(argv[1]) <= ULOG_FILTER_TAG_MAX_LEN)
        {
            ulog_global_filter_tag_set(argv[1]);
        }
        else
        {
            rt_kprintf("The tag length is too long. Max is %d.\n", ULOG_FILTER_TAG_MAX_LEN);
        }
    }
    else
    {
        ulog_global_filter_tag_set("");
    }
}
MSH_CMD_EXPORT(ulog_tag, Set ulog global filter tag);

static void ulog_kw(uint8_t argc, char **argv)
{
    if (argc > 1)
    {
        if (rt_strlen(argv[1]) <= ULOG_FILTER_KW_MAX_LEN)
        {
            ulog_global_filter_kw_set(argv[1]);
        }
        else
        {
            rt_kprintf("The keyword length is too long. Max is %d.\n", ULOG_FILTER_KW_MAX_LEN);
        }
    }
    else
    {
        ulog_global_filter_kw_set("");
    }
}
MSH_CMD_EXPORT(ulog_kw, Set ulog global filter keyword);

static void ulog_filter(uint8_t argc, char **argv)
{
#ifndef ULOG_USING_SYSLOG
    const char *lvl_name[] = { "Assert ", "Error  ", "Error  ", "Error  ", "Warning", "Info   ", "Info   ", "Debug  " };
#endif
    const char *tag = ulog_global_filter_tag_get(), *kw = ulog_global_filter_kw_get();
    rt_slist_t *node;
    ulog_tag_lvl_filter_t tag_lvl = RT_NULL;

    rt_kprintf("--------------------------------------\n");
    rt_kprintf("ulog global filter:\n");

#ifndef ULOG_USING_SYSLOG
    rt_kprintf("level   : %s\n", lvl_name[ulog_global_filter_lvl_get()]);
#else
    rt_kprintf("level   : %d\n", ulog_global_filter_lvl_get());
#endif

    rt_kprintf("tag     : %s\n", rt_strlen(tag) == 0 ? "NULL" : tag);
    rt_kprintf("keyword : %s\n", rt_strlen(kw) == 0 ? "NULL" : kw);

    rt_kprintf("--------------------------------------\n");
    rt_kprintf("ulog tag's level filter:\n");
    if (rt_slist_isempty(ulog_tag_lvl_list_get()))
    {
        rt_kprintf("settings not found\n");
    }
    else
    {
        /* lock output */
        output_lock();
        /* show the tag level list */
        for (node = rt_slist_first(ulog_tag_lvl_list_get()); node; node = rt_slist_next(node))
        {
            tag_lvl = rt_slist_entry(node, struct ulog_tag_lvl_filter, list);
            rt_kprintf("%-*.s: ", ULOG_FILTER_TAG_MAX_LEN, tag_lvl->tag);

#ifndef ULOG_USING_SYSLOG
            rt_kprintf("%s\n", lvl_name[tag_lvl->level]);
#else
            rt_kprintf("%d\n", tag_lvl->level);
#endif

        }
        /* unlock output */
        output_unlock();
    }
}
MSH_CMD_EXPORT(ulog_filter, Show ulog filter settings);
#endif /* RT_USING_FINSH */
#endif /* ULOG_USING_FILTER */

rt_err_t ulog_backend_register(ulog_backend_t backend, const char *name, rt_bool_t support_color)
{
    rt_base_t level;

    RT_ASSERT(backend);
    RT_ASSERT(name);
    RT_ASSERT(ulog.init_ok);
    RT_ASSERT(backend->output);

    if (backend->init)
    {
        backend->init(backend);
    }

    backend->support_color = support_color;
    backend->out_level = LOG_FILTER_LVL_ALL;
    rt_strncpy(backend->name, name, RT_NAME_MAX);

    level = rt_hw_interrupt_disable();
    rt_slist_append(&ulog.backend_list, &backend->list);
    rt_hw_interrupt_enable(level);

    return RT_EOK;
}

rt_err_t ulog_backend_unregister(ulog_backend_t backend)
{
    rt_base_t level;

    RT_ASSERT(backend);
    RT_ASSERT(ulog.init_ok);

    if (backend->deinit)
    {
        backend->deinit(backend);
    }

    level = rt_hw_interrupt_disable();
    rt_slist_remove(&ulog.backend_list, &backend->list);
    rt_hw_interrupt_enable(level);

    return RT_EOK;
}

rt_err_t ulog_backend_set_filter(ulog_backend_t backend, ulog_backend_filter_t filter)
{
    rt_base_t level;
    RT_ASSERT(backend);

    level = rt_hw_interrupt_disable();
    backend->filter = filter;
    rt_hw_interrupt_enable(level);

    return RT_EOK;
}

ulog_backend_t ulog_backend_find(const char *name)
{
    rt_base_t level;
    rt_slist_t *node;
    ulog_backend_t backend;

    RT_ASSERT(ulog.init_ok);

    level = rt_hw_interrupt_disable();
    for (node = rt_slist_first(&ulog.backend_list); node; node = rt_slist_next(node))
    {
        backend = rt_slist_entry(node, struct ulog_backend, list);
        if (rt_strncmp(backend->name, name, RT_NAME_MAX) == 0)
        {
            rt_hw_interrupt_enable(level);
            return backend;
        }
    }

    rt_hw_interrupt_enable(level);
    return RT_NULL;
}

#ifdef ULOG_USING_ASYNC_OUTPUT
/**
 * asynchronous output logs to all backends
 *
 * @note you must call this function when ULOG_ASYNC_OUTPUT_BY_THREAD is disable
 */
void ulog_async_output(void)
{
    rt_rbb_blk_t log_blk;
    ulog_frame_t log_frame;

    if (!ulog.async_enabled)
    {
        return;
    }

    while ((log_blk = rt_rbb_blk_get(ulog.async_rbb)) != RT_NULL)
    {
        log_frame = (ulog_frame_t) log_blk->buf;
        if (log_frame->magic == ULOG_FRAME_MAGIC)
        {
            /* output to all backends */
            ulog_output_to_all_backend(log_frame->level, log_frame->tag, log_frame->is_raw, log_frame->log,
                    log_frame->log_len);
        }
        rt_rbb_blk_free(ulog.async_rbb, log_blk);
    }
    /* output the log_raw format log */
    if (ulog.async_rb)
    {
        rt_size_t log_len = rt_ringbuffer_data_len(ulog.async_rb);
        char *log = rt_malloc(log_len + 1);
        if (log)
        {
            rt_size_t len = rt_ringbuffer_get(ulog.async_rb, (rt_uint8_t *)log, log_len);
            log[log_len] = '\0';
            ulog_output_to_all_backend(LOG_LVL_DBG, "", RT_TRUE, log, len);
            rt_free(log);
        }
    }
}

/**
 * enable or disable asynchronous output mode
 * the log will be output directly when mode is disabled
 *
 * @param enabled RT_TRUE: enabled, RT_FALSE: disabled
 */
void ulog_async_output_enabled(rt_bool_t enabled)
{
    ulog.async_enabled = enabled;
}

/**
 * waiting for get asynchronous output log
 *
 * @param time the waiting time
 *
 * @return the operation status, RT_EOK on successful
 */
rt_err_t ulog_async_waiting_log(rt_int32_t time)
{
    rt_sem_control(&ulog.async_notice, RT_IPC_CMD_RESET, RT_NULL);
    return rt_sem_take(&ulog.async_notice, time);
}

static void async_output_thread_entry(void *param)
{
    ulog_async_output();

    while (1)
    {
        ulog_async_waiting_log(RT_WAITING_FOREVER);
        while (1)
        {
            ulog_async_output();
            /* If there is no log output for a certain period of time,
             * refresh the log buffer
             */
            if (ulog_async_waiting_log(RT_TICK_PER_SECOND * 2) == RT_EOK)
            {
                continue;
            }
            else
            {
                ulog_flush();
                break;
            }
        }
    }
}
#endif /* ULOG_USING_ASYNC_OUTPUT */

/**
 * flush all backends's log
 */
void ulog_flush(void)
{
    rt_slist_t *node;
    ulog_backend_t backend;

    if (!ulog.init_ok)
        return;

#ifdef ULOG_USING_ASYNC_OUTPUT
    ulog_async_output();
#endif

    /* flush all backends */
    for (node = rt_slist_first(&ulog.backend_list); node; node = rt_slist_next(node))
    {
        backend = rt_slist_entry(node, struct ulog_backend, list);
        if (backend->flush)
        {
            backend->flush(backend);
        }
    }
}

int ulog_init(void)
{
    if (ulog.init_ok)
        return 0;

    rt_mutex_init(&ulog.output_locker, "ulog", RT_IPC_FLAG_PRIO);
    ulog.output_lock_enabled = RT_TRUE;
    rt_slist_init(&ulog.backend_list);

#ifdef ULOG_USING_FILTER
    rt_slist_init(ulog_tag_lvl_list_get());
#endif

#ifdef ULOG_USING_ASYNC_OUTPUT
    RT_ASSERT(ULOG_ASYNC_OUTPUT_STORE_LINES >= 2);
    ulog.async_enabled = RT_TRUE;
    /* async output ring block buffer */
    ulog.async_rbb = rt_rbb_create(RT_ALIGN(ULOG_ASYNC_OUTPUT_BUF_SIZE, RT_ALIGN_SIZE), ULOG_ASYNC_OUTPUT_STORE_LINES);
    if (ulog.async_rbb == RT_NULL)
    {
        rt_kprintf("Error: ulog init failed! No memory for async rbb.\n");
        rt_mutex_detach(&ulog.output_locker);
        return -RT_ENOMEM;
    }
    rt_sem_init(&ulog.async_notice, "ulog", 0, RT_IPC_FLAG_FIFO);
#endif /* ULOG_USING_ASYNC_OUTPUT */

#ifdef ULOG_USING_FILTER
    ulog_global_filter_lvl_set(LOG_FILTER_LVL_ALL);
#endif

    ulog.init_ok = RT_TRUE;

    return 0;
}
INIT_BOARD_EXPORT(ulog_init);

#ifdef ULOG_USING_ASYNC_OUTPUT
int ulog_async_init(void)
{
    if (ulog.async_th == RT_NULL)
    {
        /* async output thread */
        ulog.async_th = rt_thread_create("ulog_async", async_output_thread_entry, &ulog, ULOG_ASYNC_OUTPUT_THREAD_STACK,
                ULOG_ASYNC_OUTPUT_THREAD_PRIORITY, 20);
        if (ulog.async_th == RT_NULL)
        {
            rt_kprintf("Error: ulog init failed! No memory for async output thread.\n");
            return -RT_ENOMEM;
        }
        /* async output thread startup */
        rt_thread_startup(ulog.async_th);
    }
    return 0;
}
INIT_PREV_EXPORT(ulog_async_init);
#endif /* ULOG_USING_ASYNC_OUTPUT */

void ulog_deinit(void)
{
    rt_slist_t *node;
    ulog_backend_t backend;

    if (!ulog.init_ok)
        return;

    /* deinit all backends */
    for (node = rt_slist_first(&ulog.backend_list); node; node = rt_slist_next(node))
    {
        backend = rt_slist_entry(node, struct ulog_backend, list);
        if (backend->deinit)
        {
            backend->deinit(backend);
        }
    }

#ifdef ULOG_USING_FILTER
    /* deinit tag's level filter */
    {
        ulog_tag_lvl_filter_t tag_lvl;
        for (node = rt_slist_first(ulog_tag_lvl_list_get()); node; node = rt_slist_next(node))
        {
            tag_lvl = rt_slist_entry(node, struct ulog_tag_lvl_filter, list);
            rt_free(tag_lvl);
        }
    }
#endif /* ULOG_USING_FILTER */

    rt_mutex_detach(&ulog.output_locker);

#ifdef ULOG_USING_ASYNC_OUTPUT
    rt_rbb_destroy(ulog.async_rbb);
    rt_thread_delete(ulog.async_th);
    if (ulog.async_rb)
        rt_ringbuffer_destroy(ulog.async_rb);
#endif

    ulog.init_ok = RT_FALSE;
}

#endif /* RT_USING_ULOG */