Step to UEFI (17） ----- Application中注册一个快捷键

前面介绍过如何在 Shell 下实现暂停和中断运行。这里介绍如何实现在Application中注册一个“热键”，当按下这个键的时候去做另外的事情。

根据资料，需要使用EFI_SIMPLE_TEXT_INPUT_EX_PROTOCOL 的 RegisterKeyNotify 【参考1，2】

具体的参考代码在ShellProtocol.c

KeyData.KeyState.KeyToggleState = 0;
KeyData.Key.ScanCode = 0;
KeyData.KeyState.KeyShiftState = EFI_SHIFT_STATE_VALID|EFI_LEFT_CONTROL_PRESSED;
KeyData.Key.UnicodeChar = L'c';

Status = SimpleEx->RegisterKeyNotify(
SimpleEx,
&KeyData,
NotificationFunction,
&ShellInfoObject.CtrlCNotifyHandle1);

查阅Spec【参考3】，有如下资料

简单的说，第一个参数是EFI_SIMPLE_TEXT_INPUT_EX_PROTOCOL 的实例，第二个参数是按键信息，第三个参数是当按键发生时会被CallBack的函数，第四个参数是注册的Handle（第四个我也不太理解，琢磨一下应该是用来记录这个注册动作的东西，有了这个东西后面可以用来取消这次的注册）。

写一个简单的程序进行测试，在一个循环中，当按下 ctrl+s 的时候，自动在屏幕上输出字符串：

/** @file
    A simple, basic, application showing how the Hello application could be
    built using the "Standard C Libraries" from StdLib.

    Copyright (c) 2010 - 2011, Intel Corporation. All rights reserved.<BR>
    This program and the accompanying materials
    are licensed and made available under the terms and conditions of the BSD License
    which accompanies this distribution. The full text of the license may be found at
    http://opensource.org/licenses/bsd-license.

    THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
    WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
**/
#include  <Uefi.h>
#include  <Library/UefiLib.h>
#include  <Library/ShellCEntryLib.h>

#include  <stdio.h>
#include  <stdlib.h>
#include <wchar.h>

extern EFI_BOOT_SERVICES             *gBS;
extern EFI_SYSTEM_TABLE				 *gST;
extern EFI_RUNTIME_SERVICES 		 *gRT;

EFI_STATUS
EFIAPI
NotificationFunction(
	IN EFI_KEY_DATA	*KeyData
)
{
	printf("This is a test from www.lab-z.com \n");		
	return(EFI_SUCCESS);
}

/***
  Demonstrates basic workings of the main() function by displaying a
  welcoming message.

  Note that the UEFI command line is composed of 16-bit UCS2 wide characters.
  The easiest way to access the command line parameters is to cast Argv as:
      wchar_t **wArgv = (wchar_t **)Argv;

  @param[in]  Argc    Number of argument tokens pointed to by Argv.
  @param[in]  Argv    Array of Argc pointers to command line tokens.

  @retval  0         The application exited normally.
  @retval  Other     An error occurred.
***/
int
EFIAPI
main (
	IN EFI_HANDLE		ImageHandle,
	IN EFI_SYSTEM_TABLE *SystemTable
  )
{
	EFI_SIMPLE_TEXT_INPUT_EX_PROTOCOL *SimpleEx;
	EFI_KEY_DATA	KeyData;
	EFI_STATUS		Status;
	EFI_HANDLE		CtrlCNotifyHandle = NULL;
	INTN			i;

 	Status = gBS -> OpenProtocol(
		gST -> ConsoleInHandle,
		&gEfiSimpleTextInputExProtocolGuid,
		(VOID**)&SimpleEx,
		ImageHandle,
		NULL,
		EFI_OPEN_PROTOCOL_GET_PROTOCOL);

	if (EFI_ERROR(Status)) {
		printf("OpenProtocol ERROR!!\n");
	}		

	KeyData.KeyState.KeyToggleState = 0;
	KeyData.Key.ScanCode			= 0;
	KeyData.KeyState.KeyShiftState 	= EFI_SHIFT_STATE_VALID | EFI_LEFT_CONTROL_PRESSED;
	KeyData.Key.UnicodeChar			= L's';

	Status = SimpleEx -> RegisterKeyNotify (
			SimpleEx,
			&KeyData,
			NotificationFunction,
			&CtrlCNotifyHandle);

	for (i=0;i<200;i++) 
	 {
		printf("Test\n");		
		gBS -> Stall (5000);
      }

	Status = SimpleEx -> UnregisterKeyNotify(SimpleEx, CtrlCNotifyHandle);

  return EFI_SUCCESS;
}

 

运行结果（模拟坏境中测试的）

代码下载

registerkey

参考：
1. http://biosren.com/viewthread.php?tid=6666&highlight=RegisterKeyNotify
如何在UEFI shell做一個類似key board hook的方式?
2. http://biosren.com/viewthread.php?tid=6579&highlight=RegisterKeyNotify
UEFI HotKey事件
3. UEFI Specification 2.4 P440