Step to UEFI (65) ----- ShellWriteFile的使用

前面介绍过使用 ShellReadFile 读取文件的内容,这里介绍一下 ShellWriteFile 的使用。

例子是使用 ShellOpenFileByName 打开当前的 EFI Application,把内容读取到内存之后,创建一个名为 Test.efi 的文件,使用 ShellWriteFile 函数把内容写进去。

代码如下:

#include  <Uefi.h>
#include  <Library/UefiLib.h>
#include  <Library/ShellCEntryLib.h>
#include  <Library/ShellLib.h>
#include  <Library/MemoryAllocationLib.h>

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

int
EFIAPI
main (
  IN int Argc,
  IN CHAR16 **Argv
  )
{

  EFI_FILE_HANDLE   FileHandle;
  RETURN_STATUS     Status;
  EFI_FILE_INFO     *FileInfo = NULL;
  EFI_HANDLE        *HandleBuffer=NULL;
  UINTN  			ReadSize;
  
  //Open the file given by the parameter
  Status = ShellOpenFileByName(Argv[0], 
		(SHELL_FILE_HANDLE *)&
                FileHandle,
                EFI_FILE_MODE_READ , 0);

  if(Status != RETURN_SUCCESS) {
        Print(L"OpenFile failed!\n");
		return EFI_SUCCESS;
      }			

  //Get file size	  
  FileInfo = ShellGetFileInfo( (SHELL_FILE_HANDLE)FileHandle);	

  //Allocate a memory buffer
  HandleBuffer = AllocateZeroPool((UINTN) FileInfo-> FileSize);
  if (HandleBuffer == NULL) {
      return (SHELL_OUT_OF_RESOURCES);   }

  ReadSize=(UINTN) FileInfo-> FileSize;
  
  //Load the whole file to the buffer
  Status = ShellReadFile(FileHandle,&ReadSize,HandleBuffer);
  
  //Close the source file
  ShellCloseFile(&FileHandle);

  //Create a new file
  Status = ShellOpenFileByName(L"Test.efi", 
             (SHELL_FILE_HANDLE *)&FileHandle,
                               EFI_FILE_MODE_READ |
			       EFI_FILE_MODE_WRITE|
			       EFI_FILE_MODE_CREATE, 
			    0);  
  if(Status != RETURN_SUCCESS) {
        Print(L"CreatFile failed [%r]!\n",Status);
	    return EFI_SUCCESS;
      }	
  Status = ShellWriteFile(FileHandle,
			&ReadSize,
			HandleBuffer
			);
  //Close the source file
  ShellCloseFile(&FileHandle);
  
  return EFI_SUCCESS;
}

 

运行结果(运行结束之后我比较了一下生成文件和源文件是相同的):

ctf

特别注意:使用 ShellOpenFuleByName 创建一个文件时,要同时使用 EFI_FILE_MODE_READ ,EFI_FILE_MODE_WRITE 和 EFI_FILE_MODE_CREATE ,否则可能出现“Invalid Parameter”的错误【参考1】

完整代码下载
CreateFile

1.http://feishare.com/efimail/messages/20120331-0611-Re__edk2__Problems_creating_file_using_ShellOpenFileByName-_Bekefi__Stephen_C_.html

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