UEFI 之 代码执行uefi shell命令

概要

这需求就是类似于linux系统下的系统调用接口system("command")

EDK中实现

Shell protocol 实现

包含协议

[Protocols]
  gEfiShellProtocolGuid                  ## CONSUMES

Demo

EFI_STATUS
EFIAPI
UefiMain (
  IN EFI_HANDLE                            ImageHandle,
  IN EFI_SYSTEM_TABLE                      *SystemTable
  )
{
  EFI_SHELL_PROTOCOL    *EfiShellProtocol;
  EFI_STATUS            Status;
//初始化协议
  Status = gBS->LocateProtocol (&gEfiShellProtocolGuid,
                                NULL,
                                (VOID **) 			&EfiShellProtocol);

  if (EFI_ERROR (Status)) {
    return Status; 
  }

  EfiShellProtocol->Execute (&ImageHandle,
                             L"echo map -r",
                             NULL,
                             &Status);

  return Status;
}

Execute在 ShellPkg/Application/Shell/ShellProtocol.c

EFI_STATUS
EFIAPI
EfiShellExecute(
  IN EFI_HANDLE *ParentImageHandle,
  IN CHAR16 *CommandLine OPTIONAL,
  IN CHAR16 **Environment OPTIONAL,
  OUT EFI_STATUS *StatusCode OPTIONAL
  )
{
  EFI_STATUS                Status;
  CHAR16                    *Temp;
  EFI_DEVICE_PATH_PROTOCOL  *DevPath;
  UINTN                     Size;

  if ((PcdGet8(PcdShellSupportLevel) < 1)) {
    return (EFI_UNSUPPORTED);
  }

  if (NestingEnabled()) {
    DevPath = AppendDevicePath (ShellInfoObject.ImageDevPath, ShellInfoObject.FileDevPath);

    DEBUG_CODE_BEGIN();
    Temp = ConvertDevicePathToText(ShellInfoObject.FileDevPath, TRUE, TRUE);
    FreePool(Temp);
    Temp = ConvertDevicePathToText(ShellInfoObject.ImageDevPath, TRUE, TRUE);
    FreePool(Temp);
    Temp = ConvertDevicePathToText(DevPath, TRUE, TRUE);
    FreePool(Temp);
    DEBUG_CODE_END();

    Temp = NULL;
    Size = 0;
    ASSERT((Temp == NULL && Size == 0) || (Temp != NULL));
    StrnCatGrow(&Temp, &Size, L"Shell.efi -exit ", 0);
    StrnCatGrow(&Temp, &Size, CommandLine, 0);

    Status = InternalShellExecuteDevicePath(
      ParentImageHandle,
      DevPath,
      Temp,
      (CONST CHAR16**)Environment,
      StatusCode);

    //
    // de-allocate and return
    //
    FreePool(DevPath);
    FreePool(Temp);
  } else {
    Status = InternalShellExecute(
      (CONST CHAR16*)CommandLine,
      (CONST CHAR16**)Environment,
      StatusCode);
  }

  return(Status);
}

需要说明的是NestingEnabled跑到这里会返回无效的参数，InternalShellExecute用这个接口是可以的；我使用的是UDK2018

库

使用UefiShellLib库的接口,跟方便，位置在ShellPkg/Library/UefiShellLib

#include 

EFI_STATUS
EFIAPI
UefiMain (
  IN EFI_HANDLE                            ImageHandle,
  IN EFI_SYSTEM_TABLE                      *SystemTable
  )
{
  EFI_STATUS            Status;

  ShellExecute (&ImageHandle,
                L"echo Hello World!",
                FALSE,
                NULL,
                &Status);

  return Status;
}

其实最终调用的还是EfiShellExecute接口；

参考

https://stackoverflow.com/questions/38738862/run-a-uefi-shell-command-from-inside-uefi-application