question about uefi shell pipe.

[krishnaLee <sssky307@163.com>]

Hi,
I wrote this shell application(smalltest.efi),did some pipe function test,find some strange result.
boot into shell:


# test-1,the follow two command should has the same output ,but infact not the same in QEMU,and the second command failed WriteFile in real machine(AMI bios uefi 2.6):
ls | smalltest.efi
ls | smalltest.efi | smalltest.efi             # the ls command directory only has one file(this tool),so the tool's buffer 80x25*4 won't overflow.


#test-2
run smalltest.efi,
just key in  some chars and Enter,nothing output,why?


my test environment:
UDK2018 + vs2015
QEMU emulator version 2.10.95
OVMF_X64.fd( x64,release build)


the tool's build command:
D:\edk2-vUDK2018>build -p ShellPkg\ShellPkg.dsc -m ShellPkg\Application2\smalltest\smalltest.inf -a X64 -b RELEASE


//--------code---smalltest.c-------------


#include <Uefi.h>
#include <Library/UefiApplicationEntryPoint.h>
#include <Library/UefiLib.h>
#include <Library/UefiBootServicesTableLib.h>//global gST gBS gImageHandle
#include <Library/BaseMemoryLib.h>
#include <Library/MemoryAllocationLib.h>


#include <Protocol/Shell.h>
#include <Protocol/ShellParameters.h>



EFI_STATUS
EFIAPI
UefiMain (
IN EFI_HANDLE ImageHandle,
IN EFI_SYSTEM_TABLE *SystemTable
)
{
EFI_STATUS status;
EFI_SHELL_PROTOCOL* gShell;
EFI_SHELL_PARAMETERS_PROTOCOL*gParameters;
UINT16 Buffer[80*25*4]; //tool's buffer;
UINTN BufferSize=sizeof(Buffer);
UINTN BufferByteSize=BufferSize*sizeof(UINT16);


status=gBS->HandleProtocol(gImageHandle,&gEfiShellParametersProtocolGuid,&gParameters);
if(status!=EFI_SUCCESS)
{
Print(L"locate gEfiShellParametersProtocolGuid failed.\n");
return status;
}


status=gBS->LocateProtocol(&gEfiShellProtocolGuid,NULL,&gShell);
if(status!=EFI_SUCCESS)
{
Print(L"locate gEfiShellProtocolGuid failed.\n");
return status;
}


status=gShell->ReadFile(gParameters->StdIn,&BufferByteSize,(VOID*)Buffer);
if(status!=EFI_SUCCESS)
{
Print(L"read from gParameters->StdIn failed.\n");
return status;
}


status=gShell->WriteFile(gParameters->StdOut,&BufferByteSize,(VOID*)Buffer);
if(status!=EFI_SUCCESS)
{
Print(L"wirte gParameters->StdOut failed\n");
return status;
}


gShell->FlushFile(gParameters->StdOut);


return EFI_SUCCESS;
}


//--------code---smalltest.inf-------------


[Defines]
  INF_VERSION                    = 0x00010005
  BASE_NAME                      = smalltest
  FILE_GUID                      = 8F7D7B1D-0E1C-4c98-B12E-4EC99C400704
  MODULE_TYPE                    = UEFI_APPLICATION
  VERSION_STRING                 = 1.0
  ENTRY_POINT                    = UefiMain


[Sources]
  smalltest.c


[Packages]
  MdePkg/MdePkg.dec


[Protocols]
gEfiShellProtocolGuid
gEfiShellParametersProtocolGuid


[LibraryClasses]
  UefiApplicationEntryPoint
  UefiLib
//--------code---end----------------------------------------------------------






thank you, 
by krishna.