标签： Console

前面介绍了 Pasue 一下的方法，这里再介绍一下让程序停止执行的方法。 和 DOS 不同，Shell中的程序通常都像吃过炫迈口香糖那样—-根本停不下来…..要想能够中止运行，可以通过 Shell Environment 2 特别设置一下。

下面的代码设置了 ESC 为Break 键，运行中可以使用它来终止运行，这里的代码和前面 PauseTest的长得几乎一样：

//
// PauseTest.c
//
#include <Uefi.h>
#include <Library/UefiLib.h>
#include <Library/ShellLib.h>
#include <Library/MemoryAllocationLib.h>
#include <Library/UefiApplicationEntryPoint.h>
#include <Library/BaseMemoryLib.h>

#define SHELL_INTERFACE_PROTOCOL \
  { \
    0x47c7b223, 0xc42a, 0x11d2, 0x8e, 0x57, 0x0, 0xa0, 0xc9, 0x69, 0x72, 0x3b \
  }
EFI_GUID        ShellInterfaceProtocol  = SHELL_INTERFACE_PROTOCOL;
EFI_GUID		SEGuid = EFI_SE_EXT_SIGNATURE_GUID;
//
// The shell environment is provided by a driver.  The shell links to the
// shell environment for services.  In addition, other drivers may connect
// to the shell environment and add new internal command handlers, or
// internal protocol handlers.
//
#define SHELL_ENVIRONMENT_INTERFACE_PROTOCOL \
  { \
    0x47c7b221, 0xc42a, 0x11d2, 0x8e, 0x57, 0x0, 0xa0, 0xc9, 0x69, 0x72, 0x3b \
  }
EFI_GUID        ShellEnvProtocol = SHELL_ENVIRONMENT_INTERFACE_PROTOCOL;

#define EFI_OUTPUT_PAUSE    0x00000002

typedef struct {
  SHELLENV_EXECUTE          Execute;  // Execute a command line
  SHELLENV_GET_ENV          GetEnv;   // Get an environment variable
  SHELLENV_GET_MAP          GetMap;   // Get mapping tables
  SHELLENV_ADD_CMD          AddCmd;   // Add an internal command handler
  SHELLENV_ADD_PROT         AddProt;  // Add protocol info handler
  SHELLENV_GET_PROT         GetProt;  // Get the protocol ID
  SHELLENV_CUR_DIR          CurDir;
  SHELLENV_FILE_META_ARG    FileMetaArg;
  SHELLENV_FREE_FILE_LIST   FreeFileList;

  //
  // The following services are only used by the shell itself
  //
  SHELLENV_NEW_SHELL        NewShell;
  SHELLENV_BATCH_IS_ACTIVE  BatchIsActive;

  SHELLENV_FREE_RESOURCES   FreeResources;
} EFI_SHELL_ENVIRONMENT;

EFI_SHELL_INTERFACE             *SI;
EFI_SHELL_ENVIRONMENT           *SE;
EFI_SHELL_ENVIRONMENT2          *SE2;

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

//Copy from \Shell\Library\Misc.c
BOOLEAN
GrowBuffer (
  IN OUT EFI_STATUS   *Status,
  IN OUT VOID         **Buffer,
  IN UINTN            BufferSize
  )
/*++

Routine Description:

  Helper function called as part of the code needed
  to allocate the proper sized buffer for various 
  EFI interfaces.

Arguments:

  Status      - Current status

  Buffer      - Current allocated buffer, or NULL

  BufferSize  - Current buffer size needed
    
Returns:
    
  TRUE - if the buffer was reallocated and the caller 
  should try the API again.

--*/
{
  BOOLEAN TryAgain;

  //
  // If this is an initial request, buffer will be null with a new buffer size
  //
  if (NULL == *Buffer && BufferSize) {
    *Status = EFI_BUFFER_TOO_SMALL;
  }
  //
  // If the status code is "buffer too small", resize the buffer
  //
  TryAgain = FALSE;
  if (*Status == EFI_BUFFER_TOO_SMALL) {

    if (*Buffer) {
      FreePool (*Buffer);
    }

    *Buffer = AllocateZeroPool (BufferSize);

    if (*Buffer) {
      TryAgain = TRUE;
    } else {
      *Status = EFI_OUT_OF_RESOURCES;
    }
  }
  //
  // If there's an error, free the buffer
  //
  if (!TryAgain && EFI_ERROR (*Status) && *Buffer) {
    FreePool (*Buffer);
    *Buffer = NULL;
  }

  return TryAgain;
}

//Copy from \Shell\Library\Handle.c
EFI_STATUS
LocateHandle (
  IN EFI_LOCATE_SEARCH_TYPE       SearchType,
  IN EFI_GUID                     * Protocol OPTIONAL,
  IN VOID                         *SearchKey OPTIONAL,
  IN OUT UINTN                    *NoHandles,
  OUT EFI_HANDLE                  **Buffer
  )
/*++

Routine Description:

  Function returns an array of handles that support the requested protocol 
  in a buffer allocated from pool.

Arguments:

  SearchType           - Specifies which handle(s) are to be returned.
  Protocol             - Provides the protocol to search by.   
                         This parameter is only valid for SearchType ByProtocol.
  SearchKey            - Supplies the search key depending on the SearchType.
  NoHandles            - The number of handles returned in Buffer.
  Buffer               - A pointer to the buffer to return the requested array of 
                         handles that support Protocol.

Returns:
  
  EFI_SUCCESS           - The result array of handles was returned.
  EFI_NOT_FOUND         - No handles match the search. 
  EFI_OUT_OF_RESOURCES - There is not enough pool memory to store the matching results.

--*/
{
  EFI_STATUS  Status;
  UINTN       BufferSize;

  //
  // Initialize for GrowBuffer loop
  //
  Status      = EFI_SUCCESS;
  *Buffer     = NULL;
  BufferSize  = 50 * sizeof (EFI_HANDLE);

  //
  // Call the real function
  //
  while (GrowBuffer (&Status, (VOID **) Buffer, BufferSize)) {
    Status = gBS->LocateHandle (
                  SearchType,
                  Protocol,
                  SearchKey,
                  &BufferSize,
                  *Buffer
                  );
  }

  *NoHandles = BufferSize / sizeof (EFI_HANDLE);
  if (EFI_ERROR (Status)) {
    *NoHandles = 0;
  }

  return Status;
}

INTN
CompareGuidx (
  IN EFI_GUID     *Guid1,
  IN EFI_GUID     *Guid2
  )
/*++

Routine Description:

  Compares to GUIDs

Arguments:

  Guid1 - guid to compare
  Guid2 - guid to compare

Returns:
  =  0  if Guid1 == Guid2
  != 0  if Guid1 != Guid2 

--*/
{
  INT32 *g1;
  INT32 *g2;
  INT32 r;

  //
  // Compare 32 bits at a time
  //
  g1  = (INT32 *) Guid1;
  g2  = (INT32 *) Guid2;

  r   = g1[0] - g2[0];
  r |= g1[1] - g2[1];
  r |= g1[2] - g2[2];
  r |= g1[3] - g2[3];

  return r;
}
// Copy from \Shell\Library\Init.c
EFI_STATUS
LibInitializeShellApplication (
  IN EFI_HANDLE                   ImageHandle,
  IN EFI_SYSTEM_TABLE             *SystemTable
  )
{
  EFI_STATUS  Status;
  EFI_HANDLE  *HandleBuffer;
  UINTN       HandleNum;
  UINTN       HandleIndex;
  EFI_GUID         SESGuid         = EFI_SE_EXT_SIGNATURE_GUID;
  
  //
  // Connect to the shell interface
  //
  Status = gBS->HandleProtocol (ImageHandle, &ShellInterfaceProtocol, (VOID *) &SI);
  if (EFI_ERROR (Status)) {
    Print (L"InitShellApp: Application not started from Shell\n");
    gBS->Exit (ImageHandle, Status, 0, NULL);
  }

  //
  // Connect to the shell environment
  //
  Status = gBS->HandleProtocol (
                ImageHandle,
                &ShellEnvProtocol,
                (VOID *) &SE2
                );
  if (EFI_ERROR (Status) || !(CompareGuid (&SE2->SESGuid, &SESGuid) == 0 &&
    (SE2->MajorVersion > EFI_SHELL_MAJOR_VER ||
      (SE2->MajorVersion == EFI_SHELL_MAJOR_VER && SE2->MinorVersion >= 
EFI_SHELL_MINOR_VER))
    )
  ) {
    Status = LocateHandle (
              ByProtocol,
              &ShellEnvProtocol,
              NULL,
              &HandleNum,
              &HandleBuffer
              );
    if (EFI_ERROR (Status)) {
      Print (L"InitShellApp: 1Shell environment interfaces not found\n");
      gBS->Exit (ImageHandle, Status, 0, NULL);
    }

    Status = EFI_NOT_FOUND;
    for (HandleIndex = 0; HandleIndex < HandleNum; HandleIndex++) {
      gBS->HandleProtocol (
           HandleBuffer[HandleIndex],
           &ShellEnvProtocol,
           (VOID *) &SE2
           );
      if (CompareGuidx (&SE2->SESGuid, &SESGuid) == 0)
	  {
        Status = EFI_SUCCESS;
        break;
      }
    }

    FreePool (HandleBuffer);

    if (EFI_ERROR (Status)) {
      Print (L"InitShellApp: 2Shell environment interfaces not found\n");
      gBS->Exit (ImageHandle, Status, Status, NULL);
    }
  }

  SE = (EFI_SHELL_ENVIRONMENT *) SE2;
  
  //
  // Done with init
  //
  return Status;
}

//
// Entry point function 
//
EFI_STATUS
EFIAPI
UefiMain (
  IN EFI_HANDLE        ImageHandle,
  IN EFI_SYSTEM_TABLE  *SystemTable
  )
{
   INTN	i;
   BOOLEAN ExitMark=FALSE;
   
   gST = SystemTable;
   gBS = SystemTable -> BootServices;
   
   LibInitializeShellApplication (ImageHandle,SystemTable);
   
   while (!ExitMark) 
    {
		//Clear Screen
		gST -> ConOut -> ClearScreen(gST->ConOut);
   	    Print(L"You can break by ESC key\n");
		for (i=0;i<80*(25-1);i++)
		{
			if (SE2 -> GetExecutionBreak() ) {ExitMark=TRUE; break;}
			Print(L".");
		} 
	}
	 
  return EFI_SUCCESS;
}

运行结果：

代码：

BreakTest

前面介绍过一些Shell下常用的命令，提到了查看当前 volume 大小的命令 VOL. 在使用中，会遇到一个奇怪的问题，感觉上有时候它能输出当前盘的大小，而有时候输出的是Partition的大小，具体的原因是什么呢？下载 VOL 的代码，进行查看注意到下面的位置：

Status = RootFs->GetInfo (RootFs, &gEfiFileSystemInfoGuid, &Size, VolumeInfo);

就是说VOL命令是基于File System的，显示出来的是文件系统能够识别出来的大小。

做一个简单的实验,将U盘进行分区，下面是只有一个分区的情况

实验的结果如下：

Volume NEW VOLUME (rw)
1,003,487,232 bytes total disk space
959,131,648 bytes available on disk
4,096 bytes in each allocation unit

再使用工具将这个U盘分区

实验的结果如下：

Volume has no label (rw)
411,009,024 bytes total disk space
411,000,832 bytes available on disk
8,192 bytes in each allocation unit

显示出来的只是有文件系统的那个分区的大小。

因此,之前实验遇到的问题是:当查看的盘上只有一个分区，并且这个分区占满了全部空间的时候，显示的也是盘的大小；如果上面的分区没有占满盘的话，显示出来的只有分区大小了。

vol.c 可以在这里下载 vol

继续介绍 Shell 下面的命令。

ECHO 和DOS下的这个命令相同，这是用来回显“字符串的”，比如下面的例子

MAP 这是一个“定义用户名和设备handle映射关系”的命令。最常见的用途就是给支持文件protocol的设备分配一个盘符，比如： fs0:

另外，最常见的用法是当你进入shell之后发现忘记插入U盘，插入之后U盘的盘符不会马上可以使用，这时候可以使用 map -r 一下，让他识别。

SET 和DOS下的这个命令相同，设置环境变量。SPEC中提到，不加额外参数设定的变量是“易非失”的，这次启动在，断电再上电还是在（我试验过）。

如果使用 -v 可以设置一个“易失”的变量，断电一次就没了。前面有 “×” 表示这个变量是易失的。

VOL 显示当前的硬盘/分区容量，如果你发现Windows无法正常安装不妨试试这个命令检查一下是否使用了错误的eMMC. （后面会查看一下这个命令的代码确定究竟查看的是硬盘容量还是分区容量）

VER 显示当前使用的UEFI版本信息

TIME 显示和设置当前的时间信息（不知道如何设置时区？）

TYPE 和DOS下的这个命令相同，显示文件的内容，支持普通的ASCII和UNICODE编码。