Shell Command Development Guidelines

• Development Guidelines

Development Guidelines

You can perform the following operations to add shell commands:

1. Include the following header files:

   #include "shell.h"
   #include "shcmd.h"
   

2. Register commands. You can register commands either statically or dynamically when the system is running. In most cases, static registration is widely used by common system commands, and dynamic registration is widely used by user commands.

   1. Static registration:

      1. Register a command using a macro.

         The prototype of the macro is as follows:

         SHELLCMD_ENTRY(l, cmdType, cmdKey, paraNum, cmdHook)
         

         Table 1 Parameters of the SHELLCMD_ENTRY macro

         Parameter	Description
         l	Specifies the global variable name passed in static registration. Note that the name cannot be the same as other symbol names in the system.
         cmdType	Specifies the command type, which can be any of the following: CMD_TYPE_EX: does not support standard command parameters and will mask the command keywords you entered. For example, if you enter ls /ramfs, only /ramfs will be passed to the registration function, and ls will be masked. CMD_TYPE_STD: supports standard command parameters. All the characters you entered will be passed to the registration function after being parsed.
         cmdKey	Specifies the command keyword, which is the name used to access a shell function.
         paraNum	Specifies the maximum number of input parameters in the execution function to be called. This parameter is not supported currently.
         cmdHook	Specifies the address of the execution function, that is, the function executed by the command.

         Example:

         SHELLCMD_ENTRY(ls_shellcmd,  CMD_TYPE_EX, "ls", XARGS,  (CMD_CBK_FUNC)osShellCmdLs)
         

      2. Add options to the build/mk/liteos_tables_ldflags.mk file.

         For example, when registering the ls command, add -uls_shellcmd to the build/mk/liteos_tables_ldflags.mk file. -u is followed by the first parameter of SHELLCMD_ENTRY.

   2. Dynamic registration:

      The prototype of the function to register is as follows:

      UINT32 osCmdReg(CmdT ype cmdType, CHAR *cmdKey, UINT32 paraNum, CmdCallBackFunc cmdProc)
      

      Table 2 Parameters of UINT32 osCmdReg

      Parameter	Description
      cmdType	Specifies the command type, which can be any of the following: CMD_TYPE_EX: does not support standard command parameters and will mask the command keywords you entered. For example, if you enter ls /ramfs, only /ramfs will be passed to the registration function, and ls will be masked. CMD_TYPE_STD: supports standard command parameters. All the characters you entered will be passed to the registration function after being parsed.
      cmdKey	Specifies the command keyword, which is the name used to access a shell function.
      paraNum	Specifies the maximum number of input parameters in the execution function to be called. This parameter is not supported currently. The default value is XARGS(0xFFFFFFFF).
      cmdHook	Specifies the address of the execution function, that is, the function executed by the command.

      Example:

      osCmdReg(CMD_TYPE_EX, "ls", XARGS,  (CMD_CBK_FUNC)osShellCmdLs)
      

   NOTE: The command keyword must be unique. That is, two different commands cannot share the same command keyword. Otherwise, only one command is executed. When executing user commands sharing the same keyword, the shell executes only the first command in the help commands.

3. Use the following function prototype to add built-in commands:

   UINT32 osShellCmdLs(UINT32 argc,  CHAR **argv)
   

   Table 3 Parameters of osShellCmdLs

   Parameter	Description
   argc	Specifies the number of parameters in the shell command.
   argv	Specifies a pointer array, where each element points to a string. You can determine whether to pass the command keyword to the registration function by specifying the command type.

4. Enter the shell command in either of the following methods:

   • Enter the shell command in a serial port tool.

   • Enter the shell command in the Telnet tool. For details, see telnet.