audk/SecurityPkg/VariableAuthenticated/SecureBootConfigDxe/SecureBootConfigMisc.c

/** @file
  Helper functions for SecureBoot configuration module.

Copyright (c) 2015 - 2017, 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.php

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 "SecureBootConfigImpl.h"

/**
  Read file content into BufferPtr, the size of the allocate buffer 
  is *FileSize plus AddtionAllocateSize.

  @param[in]       FileHandle            The file to be read.
  @param[in, out]  BufferPtr             Pointers to the pointer of allocated buffer.
  @param[out]      FileSize              Size of input file
  @param[in]       AddtionAllocateSize   Addtion size the buffer need to be allocated. 
                                         In case the buffer need to contain others besides the file content.
  
  @retval   EFI_SUCCESS                  The file was read into the buffer.
  @retval   EFI_INVALID_PARAMETER        A parameter was invalid.
  @retval   EFI_OUT_OF_RESOURCES         A memory allocation failed.
  @retval   others                       Unexpected error.

**/
EFI_STATUS
ReadFileContent (
  IN      EFI_FILE_HANDLE           FileHandle,
  IN OUT  VOID                      **BufferPtr,
     OUT  UINTN                     *FileSize,
  IN      UINTN                     AddtionAllocateSize
  )

{
  UINTN      BufferSize;
  UINT64     SourceFileSize;
  VOID       *Buffer;
  EFI_STATUS Status;

  if ((FileHandle == NULL) || (FileSize == NULL)) {
    return EFI_INVALID_PARAMETER;
  }

  Buffer = NULL;

  //
  // Get the file size
  //
  Status = FileHandle->SetPosition (FileHandle, (UINT64) -1);
  if (EFI_ERROR (Status)) {
    goto ON_EXIT;
  }

  Status = FileHandle->GetPosition (FileHandle, &SourceFileSize);
  if (EFI_ERROR (Status)) {
    goto ON_EXIT;
  }
  
  Status = FileHandle->SetPosition (FileHandle, 0);
  if (EFI_ERROR (Status)) {
    goto ON_EXIT;
  }

  BufferSize = (UINTN) SourceFileSize + AddtionAllocateSize;
  Buffer =  AllocateZeroPool(BufferSize);
  if (Buffer == NULL) {
    return EFI_OUT_OF_RESOURCES;
  }

  BufferSize = (UINTN) SourceFileSize;
  *FileSize  = BufferSize;

  Status = FileHandle->Read (FileHandle, &BufferSize, Buffer);
  if (EFI_ERROR (Status) || BufferSize != *FileSize) {
    FreePool (Buffer);
    Buffer = NULL;
    Status  = EFI_BAD_BUFFER_SIZE;
    goto ON_EXIT;
  }

ON_EXIT:
  
  *BufferPtr = Buffer;
  return Status;
}

/**
  Close an open file handle.

  @param[in] FileHandle           The file handle to close.
  
**/
VOID
CloseFile (
  IN EFI_FILE_HANDLE   FileHandle
  )
{
  if (FileHandle != NULL) {
    FileHandle->Close (FileHandle);  
  }
}

/**
  Convert a nonnegative integer to an octet string of a specified length.

  @param[in]   Integer          Pointer to the nonnegative integer to be converted
  @param[in]   IntSizeInWords   Length of integer buffer in words
  @param[out]  OctetString      Converted octet string of the specified length 
  @param[in]   OSSizeInBytes    Intended length of resulting octet string in bytes

Returns:

  @retval   EFI_SUCCESS            Data conversion successfully
  @retval   EFI_BUFFER_TOOL_SMALL  Buffer is too small for output string

**/
EFI_STATUS
EFIAPI
Int2OctStr (
  IN     CONST UINTN                *Integer,
  IN     UINTN                      IntSizeInWords,
     OUT UINT8                      *OctetString,
  IN     UINTN                      OSSizeInBytes
  )
{
  CONST UINT8  *Ptr1;
  UINT8        *Ptr2;

  for (Ptr1 = (CONST UINT8 *)Integer, Ptr2 = OctetString + OSSizeInBytes - 1;
       Ptr1 < (UINT8 *)(Integer + IntSizeInWords) && Ptr2 >= OctetString;
       Ptr1++, Ptr2--) {
    *Ptr2 = *Ptr1;
  }
       
  for (; Ptr1 < (CONST UINT8 *)(Integer + IntSizeInWords) && *Ptr1 == 0; Ptr1++);
  
  if (Ptr1 < (CONST UINT8 *)(Integer + IntSizeInWords)) {
    return EFI_BUFFER_TOO_SMALL;
  }
  
  if (Ptr2 >= OctetString) {
    ZeroMem (OctetString, Ptr2 - OctetString + 1);
  }
  
  return EFI_SUCCESS;
}

/**
  Worker function that prints an EFI_GUID into specified Buffer.

  @param[in]     Guid          Pointer to GUID to print.
  @param[in]     Buffer        Buffer to print Guid into.
  @param[in]     BufferSize    Size of Buffer.
  
  @retval    Number of characters printed.

**/
UINTN
GuidToString (
  IN  EFI_GUID  *Guid,
  IN  CHAR16    *Buffer,
  IN  UINTN     BufferSize
  )
{
  UINTN Size;

  Size = UnicodeSPrint (
            Buffer,
            BufferSize, 
            L"%08x-%04x-%04x-%02x%02x-%02x%02x%02x%02x%02x%02x",
            (UINTN)Guid->Data1,                    
            (UINTN)Guid->Data2,
            (UINTN)Guid->Data3,
            (UINTN)Guid->Data4[0],
            (UINTN)Guid->Data4[1],
            (UINTN)Guid->Data4[2],
            (UINTN)Guid->Data4[3],
            (UINTN)Guid->Data4[4],
            (UINTN)Guid->Data4[5],
            (UINTN)Guid->Data4[6],
            (UINTN)Guid->Data4[7]
            );

  //
  // SPrint will null terminate the string. The -1 skips the null
  //
  return Size - 1;
}