概述本文档详细介绍如何在 OpenHarmony LiteOS-M 内核中添加自定义 shell 命令以version、reboot、poweroff命令为例进行说明。目录结构kernel/liteos_m/components/shell/ ├── include/shcmd.h # 命令声明头文件 ├── src/base/shcmd.c # 命令注册实现 ├── src/cmds/ # 命令实现目录 │ ├── version_shellcmd.c # version命令实现 │ ├── reboot_shellcmd.c # reboot命令实现 │ └── poweroff_shellcmd.c # poweroff命令实现 └── BUILD.gn # 构建配置文件开发步骤第一步创建命令实现文件在kernel/liteos_m/components/shell/src/cmds/目录下创建命令实现文件。示例version_shellcmd.c#includelos_compiler.h#includelos_debug.h#includesyspara/parameter.hINT32OsShellCmdVersion(INT32 argc,constCHAR**argv){charvalue[128]{0};// 检查参数个数if(argc!0){PRINTK(Usage: version\n);return-1;}// 输出系统信息PRINTK(OpenHarmony System\n);PRINTK(Kernel: LiteOS-M\n);// 从参数系统获取版本信息if(GetParameter(const.ohos.fullname,,value,sizeof(value))0){PRINTK(Version: %s\n,value);}else{PRINTK(Version: Unknown\n);}return0;}示例reboot_shellcmd.c#includelos_compiler.h#includelos_debug.h// LS2K300 PMC寄存器地址#definePMC_BASE_ADDR0x16124000#definePMC_RESET_REG_OFFSET0x00INT32OsShellCmdReboot(INT32 argc,constCHAR**argv){if(argc!0){PRINTK(Usage: reboot\n);return-1;}PRINTK(System rebooting...\n);// 写入复位寄存器volatileUINT32*reg(volatileUINT32*)(PMC_BASE_ADDRPMC_RESET_REG_OFFSET);*reg0x1;// 第0位写1触发复位// 内存屏障确保写入完成__asm__volatile(dbar 0:::memory);return0;}示例poweroff_shellcmd.c#includelos_compiler.h#includelos_debug.h// LS2K300 PMC寄存器地址#definePMC_BASE_ADDR0x16124000#definePMC_SHUTDOWN_REG_OFFSET0x14INT32OsShellCmdPoweroff(INT32 argc,constCHAR**argv){if(argc!0){PRINTK(Usage: poweroff\n);return-1;}PRINTK(System shutting down...\n);// 写入关机寄存器volatileUINT32*reg(volatileUINT32*)(PMC_BASE_ADDRPMC_SHUTDOWN_REG_OFFSET);*reg0x3c00;// 写入0x3c00触发关机// 内存屏障__asm__volatile(dbar 0:::memory);return0;}第二步声明命令函数在kernel/liteos_m/components/shell/include/shcmd.h文件中添加命令函数声明。#ifndefSHCMD_H#defineSHCMD_H// ... 其他声明 ...// 添加新命令声明externINT32OsShellCmdVersion(INT32 argc,constCHAR**argv);externINT32OsShellCmdReboot(INT32 argc,constCHAR**argv);externINT32OsShellCmdPoweroff(INT32 argc,constCHAR**argv);#endif第三步注册命令在kernel/liteos_m/components/shell/src/base/shcmd.c文件中注册命令。找到g_shellcmdAll数组添加新命令的注册信息STATICconstSHELL_CMD_INFO_S g_shellcmdAll[]{// ... 其他命令 ...// version 命令{.cmdKeyversion,.handler(SHELL_CMD_HANDLER)OsShellCmdVersion,.helpDisplay system version information,},// reboot 命令{.cmdKeyreboot,.handler(SHELL_CMD_HANDLER)OsShellCmdReboot,.helpReboot the system,},// poweroff 命令{.cmdKeypoweroff,.handler(SHELL_CMD_HANDLER)OsShellCmdPoweroff,.helpPower off the system,},};第四步添加构建配置在kernel/liteos_m/components/shell/BUILD.gn文件中添加新源文件。sources [ # ... 其他源文件 ... src/cmds/version_shellcmd.c, src/cmds/reboot_shellcmd.c, src/cmds/poweroff_shellcmd.c, ]如果需要使用参数系统如 version 命令还需要添加依赖external_deps [ # ... 其他依赖 ... init:parameterbase, ]第五步编译测试执行编译命令cd/home/vm/oh/oh61 hb build-pls2k300_mini_dp --gn-argsbuild_xtstrue关键概念说明1. 命令函数原型INT32OsShellCmdXXX(INT32 argc,constCHAR**argv)argc: 参数个数不包括命令本身argv: 参数数组返回值: 0 表示成功非0表示失败2. 输出函数使用PRINTK宏进行输出PRINTK(Hello World\n);PRINTK(Value: %d\n,value);3. 参数解析示例INT32OsShellCmdExample(INT32 argc,constCHAR**argv){// 无参数命令if(argc!0){PRINTK(Usage: example\n);return-1;}// 带参数命令if(argc!1){PRINTK(Usage: example param\n);return-1;}PRINTK(Param: %s\n,argv[0]);return0;}4. 硬件寄存器访问// 定义寄存器地址#defineREG_BASE0x16124000#defineREG_OFFSET0x00// 访问寄存器volatileUINT32*reg(volatileUINT32*)(REG_BASEREG_OFFSET);UINT32 value*reg;// 读寄存器*reg0x1;// 写寄存器// 内存屏障LoongArch__asm__volatile(dbar 0:::memory);常见问题1. 编译错误函数未定义错误信息undefined reference to OsShellCmdXXX解决方法检查函数是否只在 .c 文件中定义一次检查头文件中是否使用了#ifndef保护检查是否有内联函数重复定义2. 运行时显示 “Unknown”问题version 命令显示 “Version: Unknown”原因参数系统未正确加载参数配置解决方法在设备配置文件中启用参数加载# device/board/loongson/ls2k300_mini_dp/liteos_m/config.gni init_feature_begetctl_liteos true3. 编译错误头文件找不到错误信息fatal error: xxx.h: No such file or directory解决方法检查头文件路径是否正确检查 BUILD.gn 中是否添加了正确的 include_dirs完整示例代码version_shellcmd.c#includelos_compiler.h#includelos_debug.h#includesyspara/parameter.hINT32OsShellCmdVersion(INT32 argc,constCHAR**argv){charvalue[128]{0};if(argc!0){PRINTK(Usage: version\n);return-1;}PRINTK(OpenHarmony System\n);PRINTK(Kernel: LiteOS-M\n);if(GetParameter(const.ohos.fullname,,value,sizeof(value))0){PRINTK(Version: %s\n,value);}else{PRINTK(Version: Unknown\n);}return0;}reboot_shellcmd.c#includelos_compiler.h#includelos_debug.h#definePMC_BASE_ADDR0x16124000#definePMC_RESET_REG_OFFSET0x00INT32OsShellCmdReboot(INT32 argc,constCHAR**argv){if(argc!0){PRINTK(Usage: reboot\n);return-1;}PRINTK(System rebooting...\n);volatileUINT32*reg(volatileUINT32*)(PMC_BASE_ADDRPMC_RESET_REG_OFFSET);*reg0x1;__asm__volatile(dbar 0:::memory);return0;}poweroff_shellcmd.c#includelos_compiler.h#includelos_debug.h#definePMC_BASE_ADDR0x16124000#definePMC_SHUTDOWN_REG_OFFSET0x14INT32OsShellCmdPoweroff(INT32 argc,constCHAR**argv){if(argc!0){PRINTK(Usage: poweroff\n);return-1;}PRINTK(System shutting down...\n);volatileUINT32*reg(volatileUINT32*)(PMC_BASE_ADDRPMC_SHUTDOWN_REG_OFFSET);*reg0x3c00;__asm__volatile(dbar 0:::memory);return0;}调试技巧1. 使用 PRINTK 调试INT32OsShellCmdTest(INT32 argc,constCHAR**argv){PRINTK(Debug: argc %d\n,argc);for(inti0;iargc;i){PRINTK(Debug: argv[%d] %s\n,i,argv[i]);}return0;}2. 检查参数系统状态#includeinit_param.hvoidCheckParamStatus(void){intretSystemGetParameter(const.ohos.fullname,value,len);PRINTK(GetParameter ret %d\n,ret);}参考资料OpenHarmony 官方文档LiteOS-M 内核开发指南LoongArch 架构参考手册