LibSymbolInfo.cpp

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//==========================================
// Matt Pietrek
// Microsoft Systems Journal, April 1998
// Program: LibDump
// FILE: LibSymbolInfo.CPP
//==========================================

// LibSymbolInfo.cpp: implementation of the CLibSymbolInfo class.
//

#include "LibSymbolInfo.h"

using namespace std;

#define MakePtr( cast, ptr, addValue ) ( cast )( ( DWORD )( ptr ) + ( DWORD )( addValue ) )

// CLibSymbolInfo

CLibSymbolInfo::CLibSymbolInfo() {}

CLibSymbolInfo::~CLibSymbolInfo() {}

//=============================================================================
// Function: DumpSymbols
//
// Parameters:
//      LPTSTR lpszLibPathName    - The library file path name
//      CStdioFile* pFile         - Address of the file in which to dump the symbols
//
// Description:
//
// Given a library file path name, the function dumps the symbol info into the file
// pointed to by pFile.
//=============================================================================
BOOL CLibSymbolInfo::DumpSymbols( LPTSTR lpszLibPathName, ostream& pFile )
{
  if ( lpszLibPathName == NULL || pFile.bad() ) {
    assert( lpszLibPathName != NULL );
    assert( pFile.good() );
    m_strErrorMsg.assign( "NULL <lpszLibPathName> or Invalid file handle." );
    return FALSE;
  }

  if ( !Dump( lpszLibPathName, pFile ) ) return FALSE;
  return TRUE;
}

//=============================================================================
// Function: Dump
//
// Parameters:
//      As mentioned above.
//
// Description:
//
// Depending on the value specified in <m_bDump>/<m_bGrep> the routine dumps/greps
// the symbo info.
//=============================================================================
BOOL CLibSymbolInfo::Dump( LPTSTR lpszLibPathName, ostream& pFile )
{
  string             sBuff;
  MEMORY_MAPPED_FILE libFile( lpszLibPathName );

  // Ensure that the file mapping worked
  if ( FALSE == libFile.IsValid() ) {
    m_strErrorMsg = "Unable to access file ";
    m_strErrorMsg += lpszLibPathName;
    return FALSE;
  }
  // All COFF libraries start with the string "!<arch>\n".  Verify that this
  // string is at the beginning of the mapped file

  PSTR pArchiveStartString = (PSTR)libFile.GetBase();

  if ( 0 != strncmp( pArchiveStartString, IMAGE_ARCHIVE_START, IMAGE_ARCHIVE_START_SIZE ) ) {
    m_strErrorMsg.assign( "Not a valid COFF LIB file." );
    return FALSE;
  }

  // Point to the first archive member.  This entry contains the LIB symbols,
  // and immediately follows the archive start string ("!<arch>\n")
  PIMAGE_ARCHIVE_MEMBER_HEADER pMbrHdr;
  pMbrHdr = MakePtr( PIMAGE_ARCHIVE_MEMBER_HEADER, pArchiveStartString, IMAGE_ARCHIVE_START_SIZE );

  // First DWORD after this member header is a symbol count
  PDWORD pcbSymbols = ( PDWORD )( pMbrHdr + 1 ); // Pointer math!

  // The symbol count is stored in big endian format, so adjust as
  // appropriate for the target architecture
  DWORD cSymbols = ConvertBigEndian( *pcbSymbols );

  // Following the symbol count is an array of offsets to archive members
  // (essentially, embedded .OBJ files)
  PDWORD pMemberOffsets = pcbSymbols + 1; // Pointer math!

  // Following the array of member offsets is an array of offsets to symbol
  // names.
  PSTR pszSymbolName = MakePtr( PSTR, pMemberOffsets, 4 * cSymbols );

  //
  // Loop through every symbol in the first archive member
  //
  for ( unsigned i = 0; i < cSymbols; i++ ) {
    DWORD offset;

    // The offsets to the archive member that contains the symbol is stored
    // in big endian format, so convert it appropriately.
    offset = ConvertBigEndian( *pMemberOffsets );

    // Call DisplayLibInfoForSymbol, which figures out what kind of symbol
    // it is.  The "IsRegularLibSymbol" filters out symbols that are
    // internal to the linking process
    if ( IsRegularLibSymbol( pszSymbolName ) ) {
      string symbol( pszSymbolName );
      if ( IsFiltedSymbol( symbol ) ) {
        pFile << symbol << endl;
      }
    }
    // Advanced to the next symbol offset and name.  The MemberOffsets
    // array has fixed length entries, while the symbol names are
    // sequential null-terminated strings
    pMemberOffsets++;
    pszSymbolName += strlen( pszSymbolName ) + 1;
  }
  return TRUE;
}

//=============================================================================
// Filters out symbols that are internal to the linking process, and which
// the programmer never explicitly sees.
//=============================================================================
BOOL CLibSymbolInfo::IsRegularLibSymbol( PSTR pszSymbolName )
{
  if ( 0 == strncmp( pszSymbolName, "__IMPORT_DESCRIPTOR_", 20 ) ) return FALSE;

  if ( 0 == strncmp( pszSymbolName, "__NULL_IMPORT_DESCRIPTOR", 24 ) ) return FALSE;

  if ( strstr( pszSymbolName, "_NULL_THUNK_DATA" ) ) return FALSE;

  return TRUE;
}
//=============================================================================
// Filters out symbols that are not needed....
//=============================================================================
BOOL CLibSymbolInfo::IsFiltedSymbol( string& symbolName )
{
  if ( symbolName.compare( 0, 2, "__" ) == 0 ) return FALSE;
  if ( symbolName.compare( 0, 3, "??_" ) == 0 && symbolName[3] != '0' ) // Keep 'operator/='  [??_0]
    return FALSE;
  if ( symbolName[0] == '_' ) {
    symbolName.erase( 0, 1 ); // C functions ...
  }
  // Filter the internal Boost symbols
  if ( symbolName.find( "detail@boost" ) != string::npos ) return FALSE;
  if ( symbolName.find( "details@boost" ) != string::npos ) return FALSE;
  return TRUE;
}

//=============================================================================
// Converts from big endian to little endian numbers.
//=============================================================================
DWORD CLibSymbolInfo::ConvertBigEndian( DWORD bigEndian )
{
  DWORD temp = 0;

  temp |= bigEndian >> 24;
  temp |= ( ( bigEndian & 0x00FF0000 ) >> 8 );
  temp |= ( ( bigEndian & 0x0000FF00 ) << 8 );
  temp |= ( ( bigEndian & 0x000000FF ) << 24 );

  return temp;
}

string CLibSymbolInfo::GetLastError() const { return m_strErrorMsg; }

MEMORY_MAPPED_FILE::MEMORY_MAPPED_FILE( PSTR pszFileName )
{

  //
  // Given a filename, the constructor opens a file handle, creates a file
  // mapping, and maps the entire file into memory.
  //
  m_hFile                 = INVALID_HANDLE_VALUE;
  m_hFileMapping          = 0;
  m_pMemoryMappedFileBase = 0;
  m_cbFile                = 0;
  m_errCode               = errMMF_FileOpen; // Initial error code: not found
                                             // First get a file handle
  m_hFile =
      CreateFile( pszFileName, GENERIC_READ, FILE_SHARE_READ, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, (HANDLE)0 );

  if ( m_hFile == INVALID_HANDLE_VALUE ) {
    m_errCode = errMMF_FileOpen;
    return;
  }
  m_cbFile = ::GetFileSize( m_hFile, 0 );
  // Now, create a file mapping
  m_hFileMapping = CreateFileMapping( m_hFile, NULL, PAGE_READONLY, 0, 0, NULL );
  if ( m_hFileMapping == 0 ) {
    // Oops.  Something went wrong.  Clean up.
    CloseHandle( m_hFile );
    m_hFile   = INVALID_HANDLE_VALUE;
    m_errCode = errMMF_FileMapping;
    return;
  }
  m_pMemoryMappedFileBase = (PCHAR)MapViewOfFile( m_hFileMapping, FILE_MAP_READ, 0, 0, 0 );
  if ( m_pMemoryMappedFileBase == 0 ) {
    // Oops.  Something went wrong.  Clean up.
    CloseHandle( m_hFileMapping );
    m_hFileMapping = 0;
    CloseHandle( m_hFile );
    m_hFile   = INVALID_HANDLE_VALUE;
    m_errCode = errMMF_MapView;
    return;
  }
  m_errCode = errMMF_NoError;
}

MEMORY_MAPPED_FILE::~MEMORY_MAPPED_FILE( void )
{
  // Clean up everything that was created by the constructor
  if ( m_pMemoryMappedFileBase ) UnmapViewOfFile( m_pMemoryMappedFileBase );

  if ( m_hFileMapping ) CloseHandle( m_hFileMapping );

  if ( m_hFile != INVALID_HANDLE_VALUE ) CloseHandle( m_hFile );

  m_errCode = errMMF_FileOpen;
}