一种简易的嵌入式设备系统日志记录方法
在嵌入式设备应用场景中，系统日志时常可以监控设备软件的运行状态，及时记录问题点以及关键信息，方便开发人员后期定位以及解决问题。
系统日志
本文将讲述一种简易的系统日志记录方法，用于保存设备的系统日志，视具体嵌入式设备情况而定，可存储在mcu内部flash、外部flash、eeprom等，本文采用外部flash作为示例展开介绍。
思路分析
对于系统日志可以当成文件系统，可以划分为三个重要部分：目录区、参数区、日志区。目录区：根据日期进行归类，记录当天的日志的存储地址、日志索引、日志大小，通过目录可以获取整个日志文件的概况；参数区：存储记录日志写位置、目录项个数、写状态等参数；日志区：这是我们主要的存储区，记录系统的日志，支持环写。这三个区域都需要占用部分内存，可以自行分配大小。
实现的效果如下图所示，设置通过指令可查询到整个日志目录区的概况。
查询系统日志目录：
at+catalog?
log_id：存储日志按日期分类，该id用于查询对应日期日志,从1开始计数；
log_date：系统日志存储日期；
log_addr：系统日志存储外部flash地址；
log_offset：系统日志存储偏移量（各日期日志大小，单位：字节）。
另外提供移除系统日志（清除日志目录）指令：at+rmlog，后面将讲述具体实现。
flash内存划分
flash内存需要看具体设备进行合理划分，目录区、参数区与日志区实现环形存储，延长擦写寿命。
#define flash_sector_size ((uint32_t)0x001000)#define flash_block_32k_size ((uint32_t)0x008000)#define flash_block_64k_size ((uint32_t)0x010000)#define sector_mask (flash_sector_size - 1) /*扇区掩码 ------*/#define sector_base(addr) (addr & (~sector_mask)) /*扇区的基地址 --*/#define sector_offset(addr) (addr & sector_mask) /*扇区内的偏移 --*/#define block_32k_base(addr) (addr & (~(flash_block_32k_size)))#define block_64k_base(addr) (addr & (~(flash_block_64k_size)))typedef enum { flash_block_4k = 0, /**< flash erase block size 4k */ flash_block_32k = 1, /**< flash erase block size 32k */ flash_block_64k = 2 /**< flash erase block size 64k */}flash_block_t;/* flash 空间索引 */typedef enum{ flash_catalog_zone = 0, flash_syslog_para_zone, flash_syslog_zone, flash_zonex,}flash_zone_e;typedef struct{ flash_zone_e zone; uint32_t start_address; uint32_t end_address;}flash_table_t;/* 地址划分 */static const flash_table_t flash_table[] = { { .zone = flash_catalog_zone, .start_address = 0x03200000, .end_address = 0x032fffff}, { .zone = flash_syslog_para_zone, .start_address = 0x03300000, .end_address = 0x033fffff}, { .zone = flash_syslog_zone, .start_address = 0x03400000, .end_address = 0x03ffffff}, };
flash底层实现擦除、读写操作接口，由读者自行实现。
flash_table_t *get_flash_table(flash_zone_e zone){ int i = 0; for (i = 0; i flash_table_tmp->end_address) return -1; return bsp_spi_flash_erase(address, block_type);}int flash_write(flash_zone_e zone, uint32_t address, const uint8_t*data, uint32_t length){ flash_table_t *flash_table_tmp = get_flash_table(zone); if (flash_table_tmp == null) return -1; if ((address start_address) || ((address + length) > flash_table_tmp->end_address)) return -1; return bsp_spi_flash_buffer_write(address, (uint8_t *)data, length);}int flash_read(flash_zone_e zone, uint32_t address, uint8_t*buffer, uint32_t length){ flash_table_t *flash_table_tmp = get_flash_table(zone); if (flash_table_tmp == null) return -1; if ((address start_address) || ((address + length) > flash_table_tmp->end_address)) return -1; bsp_spi_flash_buffer_read(buffer, address, length); return 0;} 参数与结构体定义
日志数据存储时间戳，便于问题定位，需要实现rtc接口调用。typedef struct { uint16_t year; /* 年份:yyyy */ uint8_t month; /* 月份:mm */ uint8_t day; /* 日:dd */ uint8_t hour; /* 小时:hh */ uint8_t minute; /* 分钟:mm */ uint8_t second; /* 秒:ss */}time_t; int bsp_rtc_get_time(time_t *date);
参数区应当保证数据的正确性，应加入参数校验存储，定义校验结构体。
#define system_log_magic_param 0x87654321 /* 日志参数标识符 */typedef struct { uint32_t magic; /* 参数标识符 */ uint16_t crc; /* 校验值 */ uint16_t len; /* 参数长度 */} single_sav_t;
参数区需记录当前日志记录的写位置，以及目录项个数，还有日志区和目录区环写状态，并且存储最新时间等等。
/* 日志区参数 */typedef struct { uint32_t write_pos; /* 写位置 */ uint32_t catalog_num; /* 目录项个数 */ uint8_t log_cyclic_status; /* 系统日志环形写状态 */ uint8_t catalog_cyclic_status; /* 日志目录环形写状态 */ time_t log_latest_time; /* 存储最新时间 */}system_log_t;/* 目录区参数 */typedef struct { uint32_t log_id; /* 日志索引 */ uint32_t log_addr; /* 日志地址 */ uint32_t log_offset; /* 日志偏移大小，单位：字节 */ time_t log_time; /* 日志存储时间 */}system_catalog_t;/* 系统日志参数 */typedef struct { single_sav_t crc_val; system_log_t system_log; system_catalog_t system_catalog;}sys_log_param_t;typedef struct { uint8_t system_log_print_enable; /* 系统日志打印使能 */ uint16_t system_log_print_id; /* 打印指定id系统日志 */ uint32_t system_log_param_addr; /* 当前日志写地址 */} sys_ram_t;sys_ram_t sysram;sys_log_param_t syslogparam;sys_ram_t *gp_sys_ram = &sysram;sys_log_param_t *gp_sys_log = &syslogparam; 实现接口说明
crc校验接口，可以自定义实现。/* 16位crc校验高位表 */static const uint8_t auchcrchi[] = {0x00,0xc1,0x81,0x40,0x01,0xc0,0x80,0x41,0x01,0xc0,0x80,0x41,0x00,0xc1,0x81,0x40,0x01,0xc0,0x80,0x41,0x00,0xc1,0x81,0x40,0x00,0xc1,0x81,0x40,0x01,0xc0,0x80,0x41,0x01,0xc0,0x80,0x41,0x00,0xc1,0x81,0x40,0x00,0xc1,0x81,0x40,0x01,0xc0,0x80,0x41,0x00,0xc1,0x81,0x40,0x01,0xc0,0x80,0x41,0x01,0xc0,0x80,0x41,0x00,0xc1,0x81,0x40,0x01,0xc0,0x80,0x41,0x00,0xc1,0x81,0x40,0x00,0xc1,0x81,0x40,0x01,0xc0,0x80,0x41,0x00,0xc1,0x81,0x40,0x01,0xc0,0x80,0x41,0x01,0xc0,0x80,0x41,0x00,0xc1,0x81,0x40,0x00,0xc1,0x81,0x40,0x01,0xc0,0x80,0x41,0x01,0xc0,0x80,0x41,0x00,0xc1,0x81,0x40,0x01,0xc0,0x80,0x41,0x00,0xc1,0x81,0x40,0x00,0xc1,0x81,0x40,0x01,0xc0,0x80,0x41,0x01,0xc0,0x80,0x41,0x00,0xc1,0x81,0x40,0x00,0xc1,0x81,0x40,0x01,0xc0,0x80,0x41,0x00,0xc1,0x81,0x40,0x01,0xc0,0x80,0x41,0x01,0xc0,0x80,0x41,0x00,0xc1,0x81,0x40,0x00,0xc1,0x81,0x40,0x01,0xc0,0x80,0x41,0x01,0xc0,0x80,0x41,0x00,0xc1,0x81,0x40,0x01,0xc0,0x80,0x41,0x00,0xc1,0x81,0x40,0x00,0xc1,0x81,0x40,0x01,0xc0,0x80,0x41,0x00,0xc1,0x81,0x40,0x01,0xc0,0x80,0x41,0x01,0xc0,0x80,0x41,0x00,0xc1,0x81,0x40,0x01,0xc0,0x80,0x41,0x00,0xc1,0x81,0x40,0x00,0xc1,0x81,0x40,0x01,0xc0,0x80,0x41,0x01,0xc0,0x80,0x41,0x00,0xc1,0x81,0x40,0x00,0xc1,0x81,0x40,0x01,0xc0,0x80,0x41,0x00,0xc1,0x81,0x40,0x01,0xc0,0x80,0x41,0x01,0xc0,0x80,0x41,0x00,0xc1,0x81,0x40};/* 16位crc校验低位表 */static const uint8_t auchcrclo[] = {0x00,0xc0,0xc1,0x01,0xc3,0x03,0x02,0xc2,0xc6,0x06,0x07,0xc7,0x05,0xc5,0xc4,0x04,0xcc,0x0c,0x0d,0xcd,0x0f,0xcf,0xce,0x0e,0x0a,0xca,0xcb,0x0b,0xc9,0x09,0x08,0xc8,0xd8,0x18,0x19,0xd9,0x1b,0xdb,0xda,0x1a,0x1e,0xde,0xdf,0x1f,0xdd,0x1d,0x1c,0xdc,0x14,0xd4,0xd5,0x15,0xd7,0x17,0x16,0xd6,0xd2,0x12,0x13,0xd3,0x11,0xd1,0xd0,0x10,0xf0,0x30,0x31,0xf1,0x33,0xf3,0xf2,0x32,0x36,0xf6,0xf7,0x37,0xf5,0x35,0x34,0xf4,0x3c,0xfc,0xfd,0x3d,0xff,0x3f,0x3e,0xfe,0xfa,0x3a,0x3b,0xfb,0x39,0xf9,0xf8,0x38,0x28,0xe8,0xe9,0x29,0xeb,0x2b,0x2a,0xea,0xee,0x2e,0x2f,0xef,0x2d,0xed,0xec,0x2c,0xe4,0x24,0x25,0xe5,0x27,0xe7,0xe6,0x26,0x22,0xe2,0xe3,0x23,0xe1,0x21,0x20,0xe0,0xa0,0x60,0x61,0xa1,0x63,0xa3,0xa2,0x62,0x66,0xa6,0xa7,0x67,0xa5,0x65,0x64,0xa4,0x6c,0xac,0xad,0x6d,0xaf,0x6f,0x6e,0xae,0xaa,0x6a,0x6b,0xab,0x69,0xa9,0xa8,0x68,0x78,0xb8,0xb9,0x79,0xbb,0x7b,0x7a,0xba,0xbe,0x7e,0x7f,0xbf,0x7d,0xbd,0xbc,0x7c,0xb4,0x74,0x75,0xb5,0x77,0xb7,0xb6,0x76,0x72,0xb2,0xb3,0x73,0xb1,0x71,0x70,0xb0,0x50,0x90,0x91,0x51,0x93,0x53,0x52,0x92,0x96,0x56,0x57,0x97,0x55,0x95,0x94,0x54,0x9c,0x5c,0x5d,0x9d,0x5f,0x9f,0x9e,0x5e,0x5a,0x9a,0x9b,0x5b,0x99,0x59,0x58,0x98,0x88,0x48,0x49,0x89,0x4b,0x8b,0x8a,0x4a,0x4e,0x8e,0x8f,0x4f,0x8d,0x4d,0x4c,0x8c,0x44,0x84,0x85,0x45,0x87,0x47,0x46,0x86,0x82,0x42,0x43,0x83,0x41,0x81,0x80,0x40};/* 实现crc功能函数 */static uint16_t crc16(uint8_t* puchmsg, uint16_t usdatalen){ uint8_t uchcrchi = 0xff; uint8_t uchcrclo = 0xff; uint16_t uindex; while(usdatalen --) { uindex = uchcrchi^*(puchmsg ++); uchcrchi = uchcrclo^auchcrchi[uindex]; uchcrclo = auchcrclo[uindex]; } return uchcrchicrc_val.len = sizeof(sys_log_param_t) - sizeof(single_sav_t); gp_sys_log->crc_val.crc = crc16(&pdata[sizeof(single_sav_t)], gp_sys_log->crc_val.len); start_addr = gp_sys_ram->system_log_param_addr; /* 剩余内存不够写，则重新从起始地址开始写，实现环形存储功能 */ if ((start_addr + len) > flash_tmp->end_address) { start_addr = flash_tmp->start_address; } gp_sys_ram->system_log_param_addr = start_addr + len; /* 首地址存储，擦除整个系统日志参数存储区，如果划分的内存较大，可能出现第一次擦写等待时间较长， 但实际应用嵌入式设备应该不会占用太多的内存存储系统日志，只当为辅助使用，有额外应用可自行实现 */ if (flash_tmp->start_address == start_addr) { /*for (i = flash_tmp->start_address; i end_address; i+= flash_sector_size) flash_erase(flash_syslog_para_zone, sector_base(i), flash_block_4k); */ addr = flash_tmp->start_address; do { if ((addr + flash_block_64k_size) end_address) { flash_erase(flash_syslog_para_zone, block_64k_base(i), flash_block_64k); addr += flash_block_64k_size; } else if ((addr + flash_block_32k_size) end_address) { flash_erase(flash_syslog_para_zone, block_32k_base(i), flash_block_32k); addr += flash_block_32k_size; } else if ((addr + flash_sector_size) end_address) { flash_erase(flash_syslog_para_zone, sector_base(i), flash_block_4k); addr += flash_sector_size; } else { break; } } while (addr end_address); } remainbyte = flash_sector_size - (start_addr % flash_sector_size); if (remainbyte > len) { remainbyte = len; } while (1) { flash_write(flash_syslog_para_zone, start_addr, pdata, remainbyte); if (remainbyte == len) { break; } else { pdata += remainbyte; start_addr += remainbyte; len -= remainbyte; remainbyte = (len > flash_sector_size) ? flash_sector_size : len; } }}
导入系统日志默认参数接口，初始化默认参数或者移除日志。
void load_system_log_default_param(void){ /* 系统日志默认参数 */ /* 目录环写状态标志 */ gp_sys_log->system_log.catalog_cyclic_status = 0x00; /* 目录项个数 */ gp_sys_log->system_log.catalog_num = 0; /* 日志环写标志 , 1:环写状态 */ gp_sys_log->system_log.log_cyclic_status = 0; /* 设置默认值，实际会重新从rtc获取最新时间 */ gp_sys_log->system_log.log_latest_time.year = 2019; gp_sys_log->system_log.log_latest_time.month = 5; gp_sys_log->system_log.log_latest_time.day = 8; gp_sys_log->system_log.log_latest_time.hour = 13; gp_sys_log->system_log.log_latest_time.minute = 14; gp_sys_log->system_log.log_latest_time.second = 10; /* 日志写位置从0开始 */ gp_sys_log->system_log.write_pos = 0; gp_sys_log->system_catalog.log_addr = 0; gp_sys_log->system_catalog.log_id = 0; gp_sys_log->system_catalog.log_offset = 0; gp_sys_log->system_catalog.log_time.year = 2019; gp_sys_log->system_catalog.log_time.month = 5; gp_sys_log->system_catalog.log_time.day = 8; gp_sys_log->system_catalog.log_time.hour = 12; gp_sys_log->system_catalog.log_time.minute = 12; gp_sys_log->system_catalog.log_time.second = 14; gp_sys_log->crc_val.magic = system_log_magic_param; /* 导入默认参数后进行保存 */ save_system_log_param();}
设备开机或者复位都会进行导入系统日志参数操作，恢复日志读写参数，参数区为频繁读写操作区域，每一次写操作都会进行一次偏移，有效的导入参数方法是从参数区结束地址到起始地址进行扫描，扫描不到合法的参数则会导入默认日志参数。
/* 参数初始化，在终端启动时调用 */int load_system_log_param(void){ uint32_t i = 0; single_sav_t psav; uint32_t end_addr; uint32_t interal = sizeof(sys_log_param_t); int data_len = sizeof(sys_log_param_t) - sizeof(single_sav_t); uint8_t *pram = (uint8_t *)&syslogparam; flash_table_t *flash_tmp = get_flash_table(flash_syslog_para_zone); end_addr =flash_tmp->end_address - (flash_tmp->end_address - flash_tmp->start_address) % interal; for (i = end_addr - interal; i > flash_tmp->start_address; i -= interal) { flash_read(flash_syslog_para_zone, i, (uint8_t *)&psav, sizeof(single_sav_t)); if ((psav.magic == system_log_magic_param) && (psav.len ==data_len)) { flash_read(flash_syslog_para_zone, i + sizeof(single_sav_t), &pram[sizeof(single_sav_t)], data_len); if (psav.crc != crc16(&pram[sizeof(single_sav_t)], data_len)) continue; gp_sys_ram->system_log_param_addr = i; log_info(load system log param addr[0x%08x]!, gp_sys_ram->system_log_param_addr); return 0; } } /* 扫描不到合法的参数，导入默认系统日志参数 */ load_system_log_default_param(); /* 获取日志写地址 */ gp_sys_ram->system_log_param_addr = flash_tmp->start_address; log_info(load system log param addr(default)[0x%08x]!, gp_sys_ram->system_log_param_addr); return 1;}
读写系统日志目录接口，读写指定日志索引目录信息。实际实现会定义最新的目录信息存储在日志参数区，当日期发生改变，则表示当前目录信息已经完结，将最新的目录信息录入日志目录区保存，最多每天写入一次目录区。
/* 读取日志目录区指定日志索引目录信息 */int system_catalog_read(system_catalog_t *catalog, uint32_t id){ uint32_t addr; int rlen = sizeof(system_catalog_t); uint8_t *pbuf = (uint8_t *)catalog; flash_table_t *flash_tmp = get_flash_table(flash_catalog_zone); if (0 == id) return -1; addr = flash_tmp->start_address + (rlen * (id - 1)); if (addr > flash_tmp->end_address) return -1; return flash_read(flash_catalog_zone, addr, pbuf, rlen);}/* 写日志目录区目录信息 */int system_catalog_write(system_catalog_t *catalog, uint32_t id){ uint32_t start_offset; uint32_t start_addr; uint32_t start_base; uint32_t remainbyte; int wlen = sizeof(system_catalog_t); uint8_t *pdata = (uint8_t *)catalog; flash_table_t *flash_tmp = get_flash_table(flash_catalog_zone); if (0 == id) return -1; start_addr = flash_tmp->start_address + wlen * (id - 1); if ((start_addr + wlen) > flash_tmp->end_address) { start_addr = flash_tmp->start_address; } /* 本扇区剩余空间大小 */ remainbyte = flash_sector_size - (start_addr % flash_sector_size); /* 写入数据长度小于本扇区剩余长度，直接写入 */ if (remainbyte > wlen) { remainbyte = wlen; } /* 写目录次数不会太频繁，视具体情况改写操作实现 */ while (1) { start_base = sector_base(start_addr); start_offset = sector_offset(start_addr); flash_read(flash_catalog_zone, start_base, sector_buf, flash_sector_size); flash_erase(flash_catalog_zone, start_base, flash_block_4k); memcpy((char *)§or_buf[start_offset], pdata, remainbyte); flash_write(flash_catalog_zone, start_base, sector_buf, flash_sector_size); if (remainbyte == wlen) { break; } else { pdata += remainbyte; start_addr += remainbyte; wlen -= remainbyte; remainbyte = (wlen > flash_sector_size) ? flash_sector_size : wlen; } } return 0;}
打印系统日志目录区信息，可实现通过指令查询到目录区信息。
int system_catalog_all_print(void){ int i = 0; system_catalog_t catalog; printf(system log command information:); printf(query specifies log : at+catalog=); printf(query all log : at+catalog=); printf(query all system catalog:); printf(log_id log_date log_addr log_offset ); for (i = 0; i system_log.catalog_num; i++) { /* 当前最新目录信息 */ if (i == (gp_sys_log->system_catalog.log_id - 1)) { catalog = gp_sys_log->system_catalog; /* 获取当前最新目录信息 */ } else { system_catalog_read(&catalog, i + 1); } printf(%d %04d-%02d-%02d 0x%08x %d , catalog.log_id, catalog.log_time.year, catalog.log_time.month, catalog.log_time.day, catalog.log_addr, catalog.log_offset); memset((char *)&catalog, 0, sizeof(system_catalog_t)); } return 0;}
读取指定日志目录索引信息接口，可指定日志索引或者读取全部日志数据。
int system_log_task(int argc){ int rlen = 0; uint32_t offset, start_addr, end_addr; system_catalog_t catalog; flash_table_t *flash_tmp =get_flash_table(flash_syslog_zone); if (0 == gp_sys_ram->system_log_print_enable) return 1; gp_sys_ram->system_log_print_enable = 0x00; if (gp_sys_ram->system_log_print_id == all_log_print) { /* log回环写标志,打印整个log存储区 */ if (0x01 == gp_sys_log->system_log.log_cyclic_status) { start_addr = flash_tmp->start_address; end_addr = flash_tmp->end_address; offset = end_addr - start_addr; } else { start_addr = flash_tmp->start_address; end_addr = start_addr + gp_sys_log->system_log.write_pos; offset = gp_sys_log->system_log.write_pos; } } else { /* 读取指定id日志 */ if (gp_sys_ram->system_log_print_id == gp_sys_log->system_catalog.log_id) { catalog = gp_sys_log->system_catalog; } else { system_catalog_read(&catalog, gp_sys_ram->system_log_print_id); } start_addr = catalog.log_addr; offset = catalog.log_offset; } if (0 == offset) return 1; while (1) { rlen = (offset > 512) ? 512 : offset; system_log_read(sector_buf, start_addr, rlen); hal_delay(80); /* 目录信息通过调式串口打印 */ bsp_debug_send(sector_buf, rlen); start_addr += rlen; offset -= rlen; if (0 == offset) break; } return 0;}
存储系统日志接口，实现更新存储日期，当写位置为扇区地址，则擦除一个扇区作为存储日志，这样避免每写一次就擦除一次。
int system_log_write(uint8_t *wbuf, int wlen){ uint32_t start_addr; uint8_t *pdata = wbuf; uint32_t remainbyte; int system_catalog_max_id; flash_table_t *flash_tmp =get_flash_table(flash_syslog_zone); /* 计算目录区的最大存储目录项个数 */ system_catalog_max_id = ((flash_tmp->end_address - flash_tmp->start_address) / sizeof(system_catalog_t)); start_addr = flash_tmp->start_address + gp_sys_log->system_log.write_pos; /* 存储数据地址大于规划内存地址范围处理 */ if ((start_addr + wlen) > flash_tmp->end_address) { start_addr = flash_tmp->start_address; /* 写位置偏移量重置 */ gp_sys_log->system_log.write_pos = 0; /* log回环存储标志置位 */ gp_sys_log->system_log.log_cyclic_status = 0x01; } /* 写位置偏移 */ gp_sys_log->system_log.write_pos += wlen; if ((gp_sys_log->system_log.log_latest_time.year != gp_sys_log->system_catalog.log_time.year) || (gp_sys_log->system_log.log_latest_time.month != gp_sys_log->system_catalog.log_time.month) || (gp_sys_log->system_log.log_latest_time.day != gp_sys_log->system_catalog.log_time.day)) { /* 日期改变，记录目录信息，当log_id为0，则不写入 */ system_catalog_write(&gp_sys_log->system_catalog, gp_sys_log->system_catalog.log_id); /* 记录存储日期 */ gp_sys_log->system_catalog.log_time = gp_sys_log->system_log.log_latest_time; if ((gp_sys_log->system_catalog.log_id + 1) >= system_catalog_max_id) { gp_sys_log->system_log.catalog_num = system_catalog_max_id; /* 目录循环写，目录数应为最大 */ gp_sys_log->system_log.catalog_cyclic_status = 1; /* 目录回环写标志 */ } else { if (0 == gp_sys_log->system_log.catalog_cyclic_status) { /* 获取目录数 */ gp_sys_log->system_log.catalog_num = gp_sys_log->system_catalog.log_id + 1; } } /* 存储最新目录项信息 */ gp_sys_log->system_catalog.log_id = (gp_sys_log->system_catalog.log_id + 1) % system_catalog_max_id; gp_sys_log->system_catalog.log_addr = start_addr; gp_sys_log->system_catalog.log_offset = wlen; } else { gp_sys_log->system_catalog.log_offset += wlen; } /* 写位置为存储起始地址并且不为扇区首地址 */ if ((flash_tmp->start_address == start_addr) && (sector_offset(flash_tmp->start_address))) { flash_read(flash_syslog_zone, sector_base(start_addr), sector_buf, flash_sector_size); flash_erase(flash_syslog_zone, sector_base(start_addr), flash_block_4k); /* 将扇区头部至起始地址区间的数据回写 */ flash_write(flash_syslog_zone, sector_base(start_addr), §or_buf[0], sector_offset(start_addr)); } /* 写位置为扇区首地址，则擦除一个扇区的存储区 */ if (0 == sector_offset(start_addr)) { flash_erase(flash_syslog_zone, sector_base(start_addr), flash_block_4k); } /* 本扇区剩余空间大小 */ remainbyte = flash_sector_size - (start_addr % flash_sector_size); /* 写入数据长度小于本扇区剩余长度，直接写入 */ if (remainbyte > wlen) { remainbyte = wlen; } while (1) { flash_write(flash_syslog_zone, start_addr, pdata, remainbyte); if (remainbyte == wlen) { break; } else { pdata += remainbyte; start_addr += remainbyte; wlen -= remainbyte; remainbyte = (wlen > flash_sector_size) ? flash_sector_size : wlen; /* 扇区首地址则擦除整个扇区，该扇区数据不保存 */ if (0 == sector_offset(start_addr)) { flash_erase(flash_syslog_zone, sector_base(start_addr), flash_block_4k); } } } /* 环形存储参数 */ save_system_log_param(); return 0;} 系统调试对接
为了更好记录系统日志，将应用调试等级结合一块，实现记录错误调试信息以及需要保存的关键信息。定义的调试等级有：关闭调试等级、错误调试等级、警告调试等级、关键调试等级、debug调试等级，而log_record_level将主动保存日志并输出信息，log_error_level会存储对应的日志信息，但需要根据应用调试等级输出信息。设置与读取应用调试等级由读者自行定义。#define log_close_level 0x00 /* 关闭调试信息 */#define log_error_level 0x01 /* 错误调试信息 */#define log_warn_level 0x02 /* 警告调试信息 */#define log_info_level 0x03 /* 关键调试信息 */#define log_debug_level 0x04 /* debug调试信息 */#define log_record_level 0x10 /* 保存日志并输出信息 */ #define log_print_level 0xff#define set_log_level(level) (gp_sys_param->system_print_level = level)#define get_log_level() (gp_sys_param->system_print_level)#define log_debug(fmt, args...) log_format(log_debug_level, fmt, ##args)#define log_info(fmt, args...) log_format(log_info_level, fmt, ##args)#define log_warn(fmt, args...) log_format(log_warn_level, fmt, ##args)#define log_error(fmt, args...) log_format(log_error_level, fmt, ##args)#define log_record(fmt, args...) log_format(log_record_level, fmt, ##args)#define printf(fmt, args...) log_format(log_print_level, fmt, ##args)typedef struct { int level; char *fmt_str;}system_print_fmt_t;system_print_fmt_t system_print_fmt_list[] = { { .level = log_error_level, .fmt_str = :}, { .level = log_warn_level, .fmt_str = :}, { .level = log_info_level, .fmt_str = :}, { .level = log_debug_level, .fmt_str = :}, { .level = log_record_level, .fmt_str = :},};int log_format(uint8_t level, const char *fmt, ...){ #define time_prefix_size (21) #define print_max_size (1024 + time_prefix_size) va_list args; int num = 0, i = 0, fmt_index = 0; int fmt_str_len = 0, ret = -1; int file_str_len = 0, line_str_len = 0; char line_buf[20] = {0}; static char buf[print_max_size]; static queuehandle_t sem = null; time_t time = {0}; /* 针对os系统 */ if (null == sem) { sem = xsemaphorecreatecounting(1, 1); /* always think of success */ } xsemaphoretake(sem, portmax_delay); ret = -1; fmt_str_len = 0; if (level != log_print_level) { if ((get_log_level() < level) && (level != log_record_level) && (level != log_error_level)) goto exit_end; for (i = 0; i system_print_fmt_list_max) { goto exit_end; } fmt_str_len = strlen(system_print_fmt_list[fmt_index].fmt_str); strncpy((char *)&buf[time_prefix_size], system_print_fmt_list[fmt_index].fmt_str, fmt_str_len); } va_start(args, fmt); num = vsnprintf((char *)&buf[fmt_str_len + time_prefix_size], print_max_size - fmt_str_len - time_prefix_size - 2, fmt, args); va_end(args); if (num <= 0) { goto exit_end; } if (level != log_print_level) { num += fmt_str_len; buf[num + time_prefix_size] = ''; buf[num + time_prefix_size + 1] = ''; num += 2; } if ((get_log_level() system_log.log_latest_time = time; system_log_write((uint8_t *)buf, num + time_prefix_size); } exit_end: xsemaphoregive(sem); return ret;}
结语
本文提供的一种简易嵌入式设备系统日志记录方法，代码量不多，实现简单，针对不同的设备需要合理规划内存使用，根据软件运行状态，合适加入调试信息并保存对应的日志信息，方便开发人员了解系统或软件运行状况，协助开发分析数据资源从而更好完善系统，提高定位以及解决问题的效果。
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系统日志
本文将讲述一种简易的系统日志记录方法，用于保存设备的系统日志，视具体嵌入式设备情况而定，可存储在mcu内部flash、外部flash、eeprom等，本文采用外部flash作为示例展开介绍。
思路分析
对于系统日志可以当成文件系统，可以划分为三个重要部分：目录区、参数区、日志区。目录区：根据日期进行归类，记录当天的日志的存储地址、日志索引、日志大小，通过目录可以获取整个日志文件的概况；参数区：存储记录日志写位置、目录项个数、写状态等参数；日志区：这是我们主要的存储区，记录系统的日志，支持环写。这三个区域都需要占用部分内存，可以自行分配大小。
实现的效果如下图所示，设置通过指令可查询到整个日志目录区的概况。
查询系统日志目录：
at+catalog?
log_id：存储日志按日期分类，该id用于查询对应日期日志,从1开始计数；
log_date：系统日志存储日期；
log_addr：系统日志存储外部flash地址；
log_offset：系统日志存储偏移量（各日期日志大小，单位：字节）。
另外提供移除系统日志（清除日志目录）指令：at+rmlog，后面将讲述具体实现。
flash内存划分
flash内存需要看具体设备进行合理划分，目录区、参数区与日志区实现环形存储，延长擦写寿命。
#define flash_sector_size ((uint32_t)0x001000)#define flash_block_32k_size ((uint32_t)0x008000)#define flash_block_64k_size ((uint32_t)0x010000)#define sector_mask (flash_sector_size - 1) /*扇区掩码 ------*/#define sector_base(addr) (addr & (~sector_mask)) /*扇区的基地址 --*/#define sector_offset(addr) (addr & sector_mask) /*扇区内的偏移 --*/#define block_32k_base(addr) (addr & (~(flash_block_32k_size)))#define block_64k_base(addr) (addr & (~(flash_block_64k_size)))typedef enum { flash_block_4k = 0, /**< flash erase block size 4k */ flash_block_32k = 1, /**< flash erase block size 32k */ flash_block_64k = 2 /**< flash erase block size 64k */}flash_block_t;/* flash 空间索引 */typedef enum{ flash_catalog_zone = 0, flash_syslog_para_zone, flash_syslog_zone, flash_zonex,}flash_zone_e;typedef struct{ flash_zone_e zone; uint32_t start_address; uint32_t end_address;}flash_table_t;/* 地址划分 */static const flash_table_t flash_table[] = { { .zone = flash_catalog_zone, .start_address = 0x03200000, .end_address = 0x032fffff}, { .zone = flash_syslog_para_zone, .start_address = 0x03300000, .end_address = 0x033fffff}, { .zone = flash_syslog_zone, .start_address = 0x03400000, .end_address = 0x03ffffff}, };
flash底层实现擦除、读写操作接口，由读者自行实现。
flash_table_t *get_flash_table(flash_zone_e zone){ int i = 0; for (i = 0; i flash_table_tmp->end_address) return -1; return bsp_spi_flash_erase(address, block_type);}int flash_write(flash_zone_e zone, uint32_t address, const uint8_t*data, uint32_t length){ flash_table_t *flash_table_tmp = get_flash_table(zone); if (flash_table_tmp == null) return -1; if ((address start_address) || ((address + length) > flash_table_tmp->end_address)) return -1; return bsp_spi_flash_buffer_write(address, (uint8_t *)data, length);}int flash_read(flash_zone_e zone, uint32_t address, uint8_t*buffer, uint32_t length){ flash_table_t *flash_table_tmp = get_flash_table(zone); if (flash_table_tmp == null) return -1; if ((address start_address) || ((address + length) > flash_table_tmp->end_address)) return -1; bsp_spi_flash_buffer_read(buffer, address, length); return 0;} 参数与结构体定义
日志数据存储时间戳，便于问题定位，需要实现rtc接口调用。typedef struct { uint16_t year; /* 年份:yyyy */ uint8_t month; /* 月份:mm */ uint8_t day; /* 日:dd */ uint8_t hour; /* 小时:hh */ uint8_t minute; /* 分钟:mm */ uint8_t second; /* 秒:ss */}time_t; int bsp_rtc_get_time(time_t *date);
参数区应当保证数据的正确性，应加入参数校验存储，定义校验结构体。
#define system_log_magic_param 0x87654321 /* 日志参数标识符 */typedef struct { uint32_t magic; /* 参数标识符 */ uint16_t crc; /* 校验值 */ uint16_t len; /* 参数长度 */} single_sav_t;
参数区需记录当前日志记录的写位置，以及目录项个数，还有日志区和目录区环写状态，并且存储最新时间等等。
/* 日志区参数 */typedef struct { uint32_t write_pos; /* 写位置 */ uint32_t catalog_num; /* 目录项个数 */ uint8_t log_cyclic_status; /* 系统日志环形写状态 */ uint8_t catalog_cyclic_status; /* 日志目录环形写状态 */ time_t log_latest_time; /* 存储最新时间 */}system_log_t;/* 目录区参数 */typedef struct { uint32_t log_id; /* 日志索引 */ uint32_t log_addr; /* 日志地址 */ uint32_t log_offset; /* 日志偏移大小，单位：字节 */ time_t log_time; /* 日志存储时间 */}system_catalog_t;/* 系统日志参数 */typedef struct { single_sav_t crc_val; system_log_t system_log; system_catalog_t system_catalog;}sys_log_param_t;typedef struct { uint8_t system_log_print_enable; /* 系统日志打印使能 */ uint16_t system_log_print_id; /* 打印指定id系统日志 */ uint32_t system_log_param_addr; /* 当前日志写地址 */} sys_ram_t;sys_ram_t sysram;sys_log_param_t syslogparam;sys_ram_t *gp_sys_ram = &sysram;sys_log_param_t *gp_sys_log = &syslogparam; 实现接口说明
crc校验接口，可以自定义实现。/* 16位crc校验高位表 */static const uint8_t auchcrchi[] = {0x00,0xc1,0x81,0x40,0x01,0xc0,0x80,0x41,0x01,0xc0,0x80,0x41,0x00,0xc1,0x81,0x40,0x01,0xc0,0x80,0x41,0x00,0xc1,0x81,0x40,0x00,0xc1,0x81,0x40,0x01,0xc0,0x80,0x41,0x01,0xc0,0x80,0x41,0x00,0xc1,0x81,0x40,0x00,0xc1,0x81,0x40,0x01,0xc0,0x80,0x41,0x00,0xc1,0x81,0x40,0x01,0xc0,0x80,0x41,0x01,0xc0,0x80,0x41,0x00,0xc1,0x81,0x40,0x01,0xc0,0x80,0x41,0x00,0xc1,0x81,0x40,0x00,0xc1,0x81,0x40,0x01,0xc0,0x80,0x41,0x00,0xc1,0x81,0x40,0x01,0xc0,0x80,0x41,0x01,0xc0,0x80,0x41,0x00,0xc1,0x81,0x40,0x00,0xc1,0x81,0x40,0x01,0xc0,0x80,0x41,0x01,0xc0,0x80,0x41,0x00,0xc1,0x81,0x40,0x01,0xc0,0x80,0x41,0x00,0xc1,0x81,0x40,0x00,0xc1,0x81,0x40,0x01,0xc0,0x80,0x41,0x01,0xc0,0x80,0x41,0x00,0xc1,0x81,0x40,0x00,0xc1,0x81,0x40,0x01,0xc0,0x80,0x41,0x00,0xc1,0x81,0x40,0x01,0xc0,0x80,0x41,0x01,0xc0,0x80,0x41,0x00,0xc1,0x81,0x40,0x00,0xc1,0x81,0x40,0x01,0xc0,0x80,0x41,0x01,0xc0,0x80,0x41,0x00,0xc1,0x81,0x40,0x01,0xc0,0x80,0x41,0x00,0xc1,0x81,0x40,0x00,0xc1,0x81,0x40,0x01,0xc0,0x80,0x41,0x00,0xc1,0x81,0x40,0x01,0xc0,0x80,0x41,0x01,0xc0,0x80,0x41,0x00,0xc1,0x81,0x40,0x01,0xc0,0x80,0x41,0x00,0xc1,0x81,0x40,0x00,0xc1,0x81,0x40,0x01,0xc0,0x80,0x41,0x01,0xc0,0x80,0x41,0x00,0xc1,0x81,0x40,0x00,0xc1,0x81,0x40,0x01,0xc0,0x80,0x41,0x00,0xc1,0x81,0x40,0x01,0xc0,0x80,0x41,0x01,0xc0,0x80,0x41,0x00,0xc1,0x81,0x40};/* 16位crc校验低位表 */static const uint8_t auchcrclo[] = {0x00,0xc0,0xc1,0x01,0xc3,0x03,0x02,0xc2,0xc6,0x06,0x07,0xc7,0x05,0xc5,0xc4,0x04,0xcc,0x0c,0x0d,0xcd,0x0f,0xcf,0xce,0x0e,0x0a,0xca,0xcb,0x0b,0xc9,0x09,0x08,0xc8,0xd8,0x18,0x19,0xd9,0x1b,0xdb,0xda,0x1a,0x1e,0xde,0xdf,0x1f,0xdd,0x1d,0x1c,0xdc,0x14,0xd4,0xd5,0x15,0xd7,0x17,0x16,0xd6,0xd2,0x12,0x13,0xd3,0x11,0xd1,0xd0,0x10,0xf0,0x30,0x31,0xf1,0x33,0xf3,0xf2,0x32,0x36,0xf6,0xf7,0x37,0xf5,0x35,0x34,0xf4,0x3c,0xfc,0xfd,0x3d,0xff,0x3f,0x3e,0xfe,0xfa,0x3a,0x3b,0xfb,0x39,0xf9,0xf8,0x38,0x28,0xe8,0xe9,0x29,0xeb,0x2b,0x2a,0xea,0xee,0x2e,0x2f,0xef,0x2d,0xed,0xec,0x2c,0xe4,0x24,0x25,0xe5,0x27,0xe7,0xe6,0x26,0x22,0xe2,0xe3,0x23,0xe1,0x21,0x20,0xe0,0xa0,0x60,0x61,0xa1,0x63,0xa3,0xa2,0x62,0x66,0xa6,0xa7,0x67,0xa5,0x65,0x64,0xa4,0x6c,0xac,0xad,0x6d,0xaf,0x6f,0x6e,0xae,0xaa,0x6a,0x6b,0xab,0x69,0xa9,0xa8,0x68,0x78,0xb8,0xb9,0x79,0xbb,0x7b,0x7a,0xba,0xbe,0x7e,0x7f,0xbf,0x7d,0xbd,0xbc,0x7c,0xb4,0x74,0x75,0xb5,0x77,0xb7,0xb6,0x76,0x72,0xb2,0xb3,0x73,0xb1,0x71,0x70,0xb0,0x50,0x90,0x91,0x51,0x93,0x53,0x52,0x92,0x96,0x56,0x57,0x97,0x55,0x95,0x94,0x54,0x9c,0x5c,0x5d,0x9d,0x5f,0x9f,0x9e,0x5e,0x5a,0x9a,0x9b,0x5b,0x99,0x59,0x58,0x98,0x88,0x48,0x49,0x89,0x4b,0x8b,0x8a,0x4a,0x4e,0x8e,0x8f,0x4f,0x8d,0x4d,0x4c,0x8c,0x44,0x84,0x85,0x45,0x87,0x47,0x46,0x86,0x82,0x42,0x43,0x83,0x41,0x81,0x80,0x40};/* 实现crc功能函数 */static uint16_t crc16(uint8_t* puchmsg, uint16_t usdatalen){ uint8_t uchcrchi = 0xff; uint8_t uchcrclo = 0xff; uint16_t uindex; while(usdatalen --) { uindex = uchcrchi^*(puchmsg ++); uchcrchi = uchcrclo^auchcrchi[uindex]; uchcrclo = auchcrclo[uindex]; } return uchcrchi
导入系统日志默认参数接口，初始化默认参数或者移除日志。
void load_system_log_default_param(void){ /* 系统日志默认参数 */ /* 目录环写状态标志 */ gp_sys_log->system_log.catalog_cyclic_status = 0x00; /* 目录项个数 */ gp_sys_log->system_log.catalog_num = 0; /* 日志环写标志 , 1:环写状态 */ gp_sys_log->system_log.log_cyclic_status = 0; /* 设置默认值，实际会重新从rtc获取最新时间 */ gp_sys_log->system_log.log_latest_time.year = 2019; gp_sys_log->system_log.log_latest_time.month = 5; gp_sys_log->system_log.log_latest_time.day = 8; gp_sys_log->system_log.log_latest_time.hour = 13; gp_sys_log->system_log.log_latest_time.minute = 14; gp_sys_log->system_log.log_latest_time.second = 10; /* 日志写位置从0开始 */ gp_sys_log->system_log.write_pos = 0; gp_sys_log->system_catalog.log_addr = 0; gp_sys_log->system_catalog.log_id = 0; gp_sys_log->system_catalog.log_offset = 0; gp_sys_log->system_catalog.log_time.year = 2019; gp_sys_log->system_catalog.log_time.month = 5; gp_sys_log->system_catalog.log_time.day = 8; gp_sys_log->system_catalog.log_time.hour = 12; gp_sys_log->system_catalog.log_time.minute = 12; gp_sys_log->system_catalog.log_time.second = 14; gp_sys_log->crc_val.magic = system_log_magic_param; /* 导入默认参数后进行保存 */ save_system_log_param();}
设备开机或者复位都会进行导入系统日志参数操作，恢复日志读写参数，参数区为频繁读写操作区域，每一次写操作都会进行一次偏移，有效的导入参数方法是从参数区结束地址到起始地址进行扫描，扫描不到合法的参数则会导入默认日志参数。
/* 参数初始化，在终端启动时调用 */int load_system_log_param(void){ uint32_t i = 0; single_sav_t psav; uint32_t end_addr; uint32_t interal = sizeof(sys_log_param_t); int data_len = sizeof(sys_log_param_t) - sizeof(single_sav_t); uint8_t *pram = (uint8_t *)&syslogparam; flash_table_t *flash_tmp = get_flash_table(flash_syslog_para_zone); end_addr =flash_tmp->end_address - (flash_tmp->end_address - flash_tmp->start_address) % interal; for (i = end_addr - interal; i > flash_tmp->start_address; i -= interal) { flash_read(flash_syslog_para_zone, i, (uint8_t *)&psav, sizeof(single_sav_t)); if ((psav.magic == system_log_magic_param) && (psav.len ==data_len)) { flash_read(flash_syslog_para_zone, i + sizeof(single_sav_t), &pram[sizeof(single_sav_t)], data_len); if (psav.crc != crc16(&pram[sizeof(single_sav_t)], data_len)) continue; gp_sys_ram->system_log_param_addr = i; log_info(load system log param addr[0x%08x]!, gp_sys_ram->system_log_param_addr); return 0; } } /* 扫描不到合法的参数，导入默认系统日志参数 */ load_system_log_default_param(); /* 获取日志写地址 */ gp_sys_ram->system_log_param_addr = flash_tmp->start_address; log_info(load system log param addr(default)[0x%08x]!, gp_sys_ram->system_log_param_addr); return 1;}
读写系统日志目录接口，读写指定日志索引目录信息。实际实现会定义最新的目录信息存储在日志参数区，当日期发生改变，则表示当前目录信息已经完结，将最新的目录信息录入日志目录区保存，最多每天写入一次目录区。
/* 读取日志目录区指定日志索引目录信息 */int system_catalog_read(system_catalog_t *catalog, uint32_t id){ uint32_t addr; int rlen = sizeof(system_catalog_t); uint8_t *pbuf = (uint8_t *)catalog; flash_table_t *flash_tmp = get_flash_table(flash_catalog_zone); if (0 == id) return -1; addr = flash_tmp->start_address + (rlen * (id - 1)); if (addr > flash_tmp->end_address) return -1; return flash_read(flash_catalog_zone, addr, pbuf, rlen);}/* 写日志目录区目录信息 */int system_catalog_write(system_catalog_t *catalog, uint32_t id){ uint32_t start_offset; uint32_t start_addr; uint32_t start_base; uint32_t remainbyte; int wlen = sizeof(system_catalog_t); uint8_t *pdata = (uint8_t *)catalog; flash_table_t *flash_tmp = get_flash_table(flash_catalog_zone); if (0 == id) return -1; start_addr = flash_tmp->start_address + wlen * (id - 1); if ((start_addr + wlen) > flash_tmp->end_address) { start_addr = flash_tmp->start_address; } /* 本扇区剩余空间大小 */ remainbyte = flash_sector_size - (start_addr % flash_sector_size); /* 写入数据长度小于本扇区剩余长度，直接写入 */ if (remainbyte > wlen) { remainbyte = wlen; } /* 写目录次数不会太频繁，视具体情况改写操作实现 */ while (1) { start_base = sector_base(start_addr); start_offset = sector_offset(start_addr); flash_read(flash_catalog_zone, start_base, sector_buf, flash_sector_size); flash_erase(flash_catalog_zone, start_base, flash_block_4k); memcpy((char *)§or_buf[start_offset], pdata, remainbyte); flash_write(flash_catalog_zone, start_base, sector_buf, flash_sector_size); if (remainbyte == wlen) { break; } else { pdata += remainbyte; start_addr += remainbyte; wlen -= remainbyte; remainbyte = (wlen > flash_sector_size) ? flash_sector_size : wlen; } } return 0;}
打印系统日志目录区信息，可实现通过指令查询到目录区信息。
int system_catalog_all_print(void){ int i = 0; system_catalog_t catalog; printf(system log command information:); printf(query specifies log : at+catalog=); printf(query all log : at+catalog=); printf(query all system catalog:); printf(log_id log_date log_addr log_offset ); for (i = 0; i system_log.catalog_num; i++) { /* 当前最新目录信息 */ if (i == (gp_sys_log->system_catalog.log_id - 1)) { catalog = gp_sys_log->system_catalog; /* 获取当前最新目录信息 */ } else { system_catalog_read(&catalog, i + 1); } printf(%d %04d-%02d-%02d 0x%08x %d , catalog.log_id, catalog.log_time.year, catalog.log_time.month, catalog.log_time.day, catalog.log_addr, catalog.log_offset); memset((char *)&catalog, 0, sizeof(system_catalog_t)); } return 0;}
读取指定日志目录索引信息接口，可指定日志索引或者读取全部日志数据。
int system_log_task(int argc){ int rlen = 0; uint32_t offset, start_addr, end_addr; system_catalog_t catalog; flash_table_t *flash_tmp =get_flash_table(flash_syslog_zone); if (0 == gp_sys_ram->system_log_print_enable) return 1; gp_sys_ram->system_log_print_enable = 0x00; if (gp_sys_ram->system_log_print_id == all_log_print) { /* log回环写标志,打印整个log存储区 */ if (0x01 == gp_sys_log->system_log.log_cyclic_status) { start_addr = flash_tmp->start_address; end_addr = flash_tmp->end_address; offset = end_addr - start_addr; } else { start_addr = flash_tmp->start_address; end_addr = start_addr + gp_sys_log->system_log.write_pos; offset = gp_sys_log->system_log.write_pos; } } else { /* 读取指定id日志 */ if (gp_sys_ram->system_log_print_id == gp_sys_log->system_catalog.log_id) { catalog = gp_sys_log->system_catalog; } else { system_catalog_read(&catalog, gp_sys_ram->system_log_print_id); } start_addr = catalog.log_addr; offset = catalog.log_offset; } if (0 == offset) return 1; while (1) { rlen = (offset > 512) ? 512 : offset; system_log_read(sector_buf, start_addr, rlen); hal_delay(80); /* 目录信息通过调式串口打印 */ bsp_debug_send(sector_buf, rlen); start_addr += rlen; offset -= rlen; if (0 == offset) break; } return 0;}
存储系统日志接口，实现更新存储日期，当写位置为扇区地址，则擦除一个扇区作为存储日志，这样避免每写一次就擦除一次。
int system_log_write(uint8_t *wbuf, int wlen){ uint32_t start_addr; uint8_t *pdata = wbuf; uint32_t remainbyte; int system_catalog_max_id; flash_table_t *flash_tmp =get_flash_table(flash_syslog_zone); /* 计算目录区的最大存储目录项个数 */ system_catalog_max_id = ((flash_tmp->end_address - flash_tmp->start_address) / sizeof(system_catalog_t)); start_addr = flash_tmp->start_address + gp_sys_log->system_log.write_pos; /* 存储数据地址大于规划内存地址范围处理 */ if ((start_addr + wlen) > flash_tmp->end_address) { start_addr = flash_tmp->start_address; /* 写位置偏移量重置 */ gp_sys_log->system_log.write_pos = 0; /* log回环存储标志置位 */ gp_sys_log->system_log.log_cyclic_status = 0x01; } /* 写位置偏移 */ gp_sys_log->system_log.write_pos += wlen; if ((gp_sys_log->system_log.log_latest_time.year != gp_sys_log->system_catalog.log_time.year) || (gp_sys_log->system_log.log_latest_time.month != gp_sys_log->system_catalog.log_time.month) || (gp_sys_log->system_log.log_latest_time.day != gp_sys_log->system_catalog.log_time.day)) { /* 日期改变，记录目录信息，当log_id为0，则不写入 */ system_catalog_write(&gp_sys_log->system_catalog, gp_sys_log->system_catalog.log_id); /* 记录存储日期 */ gp_sys_log->system_catalog.log_time = gp_sys_log->system_log.log_latest_time; if ((gp_sys_log->system_catalog.log_id + 1) >= system_catalog_max_id) { gp_sys_log->system_log.catalog_num = system_catalog_max_id; /* 目录循环写，目录数应为最大 */ gp_sys_log->system_log.catalog_cyclic_status = 1; /* 目录回环写标志 */ } else { if (0 == gp_sys_log->system_log.catalog_cyclic_status) { /* 获取目录数 */ gp_sys_log->system_log.catalog_num = gp_sys_log->system_catalog.log_id + 1; } } /* 存储最新目录项信息 */ gp_sys_log->system_catalog.log_id = (gp_sys_log->system_catalog.log_id + 1) % system_catalog_max_id; gp_sys_log->system_catalog.log_addr = start_addr; gp_sys_log->system_catalog.log_offset = wlen; } else { gp_sys_log->system_catalog.log_offset += wlen; } /* 写位置为存储起始地址并且不为扇区首地址 */ if ((flash_tmp->start_address == start_addr) && (sector_offset(flash_tmp->start_address))) { flash_read(flash_syslog_zone, sector_base(start_addr), sector_buf, flash_sector_size); flash_erase(flash_syslog_zone, sector_base(start_addr), flash_block_4k); /* 将扇区头部至起始地址区间的数据回写 */ flash_write(flash_syslog_zone, sector_base(start_addr), §or_buf[0], sector_offset(start_addr)); } /* 写位置为扇区首地址，则擦除一个扇区的存储区 */ if (0 == sector_offset(start_addr)) { flash_erase(flash_syslog_zone, sector_base(start_addr), flash_block_4k); } /* 本扇区剩余空间大小 */ remainbyte = flash_sector_size - (start_addr % flash_sector_size); /* 写入数据长度小于本扇区剩余长度，直接写入 */ if (remainbyte > wlen) { remainbyte = wlen; } while (1) { flash_write(flash_syslog_zone, start_addr, pdata, remainbyte); if (remainbyte == wlen) { break; } else { pdata += remainbyte; start_addr += remainbyte; wlen -= remainbyte; remainbyte = (wlen > flash_sector_size) ? flash_sector_size : wlen; /* 扇区首地址则擦除整个扇区，该扇区数据不保存 */ if (0 == sector_offset(start_addr)) { flash_erase(flash_syslog_zone, sector_base(start_addr), flash_block_4k); } } } /* 环形存储参数 */ save_system_log_param(); return 0;} 系统调试对接
为了更好记录系统日志，将应用调试等级结合一块，实现记录错误调试信息以及需要保存的关键信息。定义的调试等级有：关闭调试等级、错误调试等级、警告调试等级、关键调试等级、debug调试等级，而log_record_level将主动保存日志并输出信息，log_error_level会存储对应的日志信息，但需要根据应用调试等级输出信息。设置与读取应用调试等级由读者自行定义。#define log_close_level 0x00 /* 关闭调试信息 */#define log_error_level 0x01 /* 错误调试信息 */#define log_warn_level 0x02 /* 警告调试信息 */#define log_info_level 0x03 /* 关键调试信息 */#define log_debug_level 0x04 /* debug调试信息 */#define log_record_level 0x10 /* 保存日志并输出信息 */ #define log_print_level 0xff#define set_log_level(level) (gp_sys_param->system_print_level = level)#define get_log_level() (gp_sys_param->system_print_level)#define log_debug(fmt, args...) log_format(log_debug_level, fmt, ##args)#define log_info(fmt, args...) log_format(log_info_level, fmt, ##args)#define log_warn(fmt, args...) log_format(log_warn_level, fmt, ##args)#define log_error(fmt, args...) log_format(log_error_level, fmt, ##args)#define log_record(fmt, args...) log_format(log_record_level, fmt, ##args)#define printf(fmt, args...) log_format(log_print_level, fmt, ##args)typedef struct { int level; char *fmt_str;}system_print_fmt_t;system_print_fmt_t system_print_fmt_list[] = { { .level = log_error_level, .fmt_str = :}, { .level = log_warn_level, .fmt_str = :}, { .level = log_info_level, .fmt_str = :}, { .level = log_debug_level, .fmt_str = :}, { .level = log_record_level, .fmt_str = :},};int log_format(uint8_t level, const char *fmt, ...){ #define time_prefix_size (21) #define print_max_size (1024 + time_prefix_size) va_list args; int num = 0, i = 0, fmt_index = 0; int fmt_str_len = 0, ret = -1; int file_str_len = 0, line_str_len = 0; char line_buf[20] = {0}; static char buf[print_max_size]; static queuehandle_t sem = null; time_t time = {0}; /* 针对os系统 */ if (null == sem) { sem = xsemaphorecreatecounting(1, 1); /* always think of success */ } xsemaphoretake(sem, portmax_delay); ret = -1; fmt_str_len = 0; if (level != log_print_level) { if ((get_log_level() < level) && (level != log_record_level) && (level != log_error_level)) goto exit_end; for (i = 0; i system_print_fmt_list_max) { goto exit_end; } fmt_str_len = strlen(system_print_fmt_list[fmt_index].fmt_str); strncpy((char *)&buf[time_prefix_size], system_print_fmt_list[fmt_index].fmt_str, fmt_str_len); } va_start(args, fmt); num = vsnprintf((char *)&buf[fmt_str_len + time_prefix_size], print_max_size - fmt_str_len - time_prefix_size - 2, fmt, args); va_end(args); if (num <= 0) { goto exit_end; } if (level != log_print_level) { num += fmt_str_len; buf[num + time_prefix_size] = ''; buf[num + time_prefix_size + 1] = ''; num += 2; } if ((get_log_level() system_log.log_latest_time = time; system_log_write((uint8_t *)buf, num + time_prefix_size); } exit_end: xsemaphoregive(sem); return ret;}
结语
本文提供的一种简易嵌入式设备系统日志记录方法，代码量不多，实现简单，针对不同的设备需要合理规划内存使用，根据软件运行状态，合适加入调试信息并保存对应的日志信息，方便开发人员了解系统或软件运行状况，协助开发分析数据资源从而更好完善系统，提高定位以及解决问题的效果。
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