/** @file
  Provides the services to get the entry point to a PE/COFF image that has either been 
  loaded into memory or is executing at it's linked address.

  Copyright (c) 2006 - 2008, Intel Corporation<BR>
  All rights reserved. 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 <Base.h>

#include <Library/PeCoffGetEntryPointLib.h>
#include <Library/DebugLib.h>

#include <IndustryStandard/PeImage.h>

/**
  Retrieves and returns a pointer to the entry point to a PE/COFF image that has been loaded
  into system memory with the PE/COFF Loader Library functions.

  Retrieves the entry point to the PE/COFF image specified by Pe32Data and returns this entry
  point in EntryPoint.  If the entry point could not be retrieved from the PE/COFF image, then
  return RETURN_INVALID_PARAMETER.  Otherwise return RETURN_SUCCESS.
  If Pe32Data is NULL, then ASSERT().
  If EntryPoint is NULL, then ASSERT().

  @param  Pe32Data                  Pointer to the PE/COFF image that is loaded in system memory.
  @param  EntryPoint                Pointer to entry point to the PE/COFF image to return.

  @retval RETURN_SUCCESS            EntryPoint was returned.
  @retval RETURN_INVALID_PARAMETER  The entry point could not be found in the PE/COFF image.

**/
RETURN_STATUS
EFIAPI
PeCoffLoaderGetEntryPoint (
  IN  VOID  *Pe32Data,
  OUT VOID  **EntryPoint
  )
{
  EFI_IMAGE_DOS_HEADER                  *DosHdr;
  EFI_IMAGE_OPTIONAL_HEADER_PTR_UNION   Hdr;

  ASSERT (Pe32Data   != NULL);
  ASSERT (EntryPoint != NULL);

  DosHdr = (EFI_IMAGE_DOS_HEADER *)Pe32Data;
  if (DosHdr->e_magic == EFI_IMAGE_DOS_SIGNATURE) {
    //
    // DOS image header is present, so read the PE header after the DOS image header.
    //
    Hdr.Pe32 = (EFI_IMAGE_NT_HEADERS32 *)((UINTN) Pe32Data + (UINTN) ((DosHdr->e_lfanew) & 0x0ffff));
  } else {
    //
    // DOS image header is not present, so PE header is at the image base.
    //
    Hdr.Pe32 = (EFI_IMAGE_NT_HEADERS32 *)Pe32Data;
  }

  //
  // Calculate the entry point relative to the start of the image.
  // AddressOfEntryPoint is common for PE32 & PE32+
  //
  if (Hdr.Te->Signature == EFI_TE_IMAGE_HEADER_SIGNATURE) {
    *EntryPoint = (VOID *)((UINTN)Pe32Data + (UINTN)(Hdr.Te->AddressOfEntryPoint & 0x0ffffffff) + sizeof(EFI_TE_IMAGE_HEADER) - Hdr.Te->StrippedSize);
    return RETURN_SUCCESS;
  } else if (Hdr.Pe32->Signature == EFI_IMAGE_NT_SIGNATURE) {
    *EntryPoint = (VOID *)((UINTN)Pe32Data + (UINTN)(Hdr.Pe32->OptionalHeader.AddressOfEntryPoint & 0x0ffffffff));
    return RETURN_SUCCESS;
  }

  return RETURN_UNSUPPORTED;
}


/**
  Returns the machine type of a PE/COFF image.

  Returns the machine type from the PE/COFF image specified by Pe32Data.
  If Pe32Data is NULL, then ASSERT().

  @param  Pe32Data   Pointer to the PE/COFF image that is loaded in system
                     memory.

  @return Machine type or zero if not a valid iamge.

**/
UINT16
EFIAPI
PeCoffLoaderGetMachineType (
  IN VOID  *Pe32Data
  )
{
  EFI_IMAGE_OPTIONAL_HEADER_PTR_UNION  Hdr;
  EFI_IMAGE_DOS_HEADER                 *DosHdr;

  ASSERT (Pe32Data != NULL);

  DosHdr = (EFI_IMAGE_DOS_HEADER *)Pe32Data;
  if (DosHdr->e_magic == EFI_IMAGE_DOS_SIGNATURE) {
    //
    // DOS image header is present, so read the PE header after the DOS image header.
    //
    Hdr.Pe32 = (EFI_IMAGE_NT_HEADERS32 *)((UINTN) Pe32Data + (UINTN) ((DosHdr->e_lfanew) & 0x0ffff));
  } else {
    //
    // DOS image header is not present, so PE header is at the image base.
    //
    Hdr.Pe32 = (EFI_IMAGE_NT_HEADERS32 *)Pe32Data;
  }

  if (Hdr.Te->Signature == EFI_TE_IMAGE_HEADER_SIGNATURE) {
    return Hdr.Te->Machine;
  } else if (Hdr.Pe32->Signature == EFI_IMAGE_NT_SIGNATURE)  {
    return Hdr.Pe32->FileHeader.Machine;
  }

  return 0x0000;
}

/**
  Returns a pointer to the PDB file name for a PE/COFF image that has been
  loaded into system memory with the PE/COFF Loader Library functions. 

  Returns the PDB file name for the PE/COFF image specified by Pe32Data.  If
  the PE/COFF image specified by Pe32Data is not a valid, then NULL is
  returned.  If the PE/COFF image specified by Pe32Data does not contain a
  debug directory entry, then NULL is returned.  If the debug directory entry
  in the PE/COFF image specified by Pe32Data does not contain a PDB file name,
  then NULL is returned.
  If Pe32Data is NULL, then ASSERT().

  @param  Pe32Data   Pointer to the PE/COFF image that is loaded in system
                     memory.

  @return The PDB file name for the PE/COFF image specified by Pe32Data or NULL
          if it cannot be retrieved.

**/
VOID *
EFIAPI
PeCoffLoaderGetPdbPointer (
  IN VOID  *Pe32Data
  )
{
  EFI_IMAGE_DOS_HEADER                  *DosHdr;
  EFI_IMAGE_OPTIONAL_HEADER_PTR_UNION   Hdr;
  EFI_IMAGE_DATA_DIRECTORY              *DirectoryEntry;
  EFI_IMAGE_DEBUG_DIRECTORY_ENTRY       *DebugEntry;
  UINTN                                 DirCount;
  VOID                                  *CodeViewEntryPointer;
  INTN                                  TEImageAdjust;
  UINT32                                NumberOfRvaAndSizes;
  UINT16                                Magic;

  ASSERT (Pe32Data   != NULL);

  TEImageAdjust       = 0;
  DirectoryEntry      = NULL;
  DebugEntry          = NULL;
  NumberOfRvaAndSizes = 0;

  DosHdr = (EFI_IMAGE_DOS_HEADER *)Pe32Data;
  if (DosHdr->e_magic == EFI_IMAGE_DOS_SIGNATURE) {
    //
    // DOS image header is present, so read the PE header after the DOS image header.
    //
    Hdr.Pe32 = (EFI_IMAGE_NT_HEADERS32 *)((UINTN) Pe32Data + (UINTN) ((DosHdr->e_lfanew) & 0x0ffff));
  } else {
    //
    // DOS image header is not present, so PE header is at the image base.
    //
    Hdr.Pe32 = (EFI_IMAGE_NT_HEADERS32 *)Pe32Data;
  }

  if (Hdr.Te->Signature == EFI_TE_IMAGE_HEADER_SIGNATURE) {
    if (Hdr.Te->DataDirectory[EFI_TE_IMAGE_DIRECTORY_ENTRY_DEBUG].VirtualAddress != 0) {
      DirectoryEntry  = &Hdr.Te->DataDirectory[EFI_TE_IMAGE_DIRECTORY_ENTRY_DEBUG];
      TEImageAdjust   = sizeof (EFI_TE_IMAGE_HEADER) - Hdr.Te->StrippedSize;
      DebugEntry = (EFI_IMAGE_DEBUG_DIRECTORY_ENTRY *)((UINTN) Hdr.Te +
                    Hdr.Te->DataDirectory[EFI_TE_IMAGE_DIRECTORY_ENTRY_DEBUG].VirtualAddress +
                    TEImageAdjust);
    }
  } else if (Hdr.Pe32->Signature == EFI_IMAGE_NT_SIGNATURE) {
    //
    // NOTE: We use Machine field to identify PE32/PE32+, instead of Magic.
    //       It is due to backward-compatibility, for some system might
    //       generate PE32+ image with PE32 Magic.
    //
    switch (Hdr.Pe32->FileHeader.Machine) {
    case IMAGE_FILE_MACHINE_I386:
      //
      // Assume PE32 image with IA32 Machine field.
      //
      Magic = EFI_IMAGE_NT_OPTIONAL_HDR32_MAGIC;
      break;
    case IMAGE_FILE_MACHINE_X64:
    case IMAGE_FILE_MACHINE_IA64:
      //
      // Assume PE32+ image with x64 or IA64 Machine field
      //
      Magic = EFI_IMAGE_NT_OPTIONAL_HDR64_MAGIC;
      break;
    default:
      //
      // For unknow Machine field, use Magic in optional Header
      //
      Magic = Hdr.Pe32->OptionalHeader.Magic;
    }

    if (Magic == EFI_IMAGE_NT_OPTIONAL_HDR32_MAGIC) {
      //
      // Use PE32 offset get Debug Directory Entry
      //
      NumberOfRvaAndSizes = Hdr.Pe32->OptionalHeader.NumberOfRvaAndSizes;
      DirectoryEntry = (EFI_IMAGE_DATA_DIRECTORY *)&(Hdr.Pe32->OptionalHeader.DataDirectory[EFI_IMAGE_DIRECTORY_ENTRY_DEBUG]);
      DebugEntry     = (EFI_IMAGE_DEBUG_DIRECTORY_ENTRY *) ((UINTN) Pe32Data + DirectoryEntry->VirtualAddress);
    } else if (Hdr.Pe32->OptionalHeader.Magic == EFI_IMAGE_NT_OPTIONAL_HDR64_MAGIC) {
      //
      // Use PE32+ offset get Debug Directory Entry
      //
      NumberOfRvaAndSizes = Hdr.Pe32Plus->OptionalHeader.NumberOfRvaAndSizes;
      DirectoryEntry = (EFI_IMAGE_DATA_DIRECTORY *)&(Hdr.Pe32Plus->OptionalHeader.DataDirectory[EFI_IMAGE_DIRECTORY_ENTRY_DEBUG]);
      DebugEntry     = (EFI_IMAGE_DEBUG_DIRECTORY_ENTRY *) ((UINTN) Pe32Data + DirectoryEntry->VirtualAddress);
    }

    if (NumberOfRvaAndSizes <= EFI_IMAGE_DIRECTORY_ENTRY_DEBUG) {
      DirectoryEntry = NULL;
      DebugEntry = NULL;
    }
  } else {
    return NULL;
  }

  if (DebugEntry == NULL || DirectoryEntry == NULL) {
    return NULL;
  }

  //
  // Scan the directory to find the debug entry.
  // 
  for (DirCount = 0; DirCount < DirectoryEntry->Size; DirCount += sizeof (EFI_IMAGE_DEBUG_DIRECTORY_ENTRY), DebugEntry++) {
    if (DebugEntry->Type == EFI_IMAGE_DEBUG_TYPE_CODEVIEW) {
      if (DebugEntry->SizeOfData > 0) {
        CodeViewEntryPointer = (VOID *) ((UINTN) DebugEntry->RVA + ((UINTN)Pe32Data) + (UINTN)TEImageAdjust);
        switch (* (UINT32 *) CodeViewEntryPointer) {
        case CODEVIEW_SIGNATURE_NB10:
          return (VOID *) ((CHAR8 *)CodeViewEntryPointer + sizeof (EFI_IMAGE_DEBUG_CODEVIEW_NB10_ENTRY));
        case CODEVIEW_SIGNATURE_RSDS:
          return (VOID *) ((CHAR8 *)CodeViewEntryPointer + sizeof (EFI_IMAGE_DEBUG_CODEVIEW_RSDS_ENTRY));
        default:
          break;
        }
      }
    }
  }

  return NULL;
}