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73 lines
2.4 KiB
C++
73 lines
2.4 KiB
C++
15 years ago
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//==========================================
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// Matt Pietrek
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// Microsoft Systems Journal, Feb 1997
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// FILE: EXEFILE.CPP
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//==========================================
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#include <windows.h>
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#pragma hdrstop
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#include "exefile.h"
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EXE_FILE::EXE_FILE( PSTR pszFileName ) : MEMORY_MAPPED_FILE( pszFileName )
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{
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m_errorType = errEXE_FILE_FILE_NOT_FOUND;
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m_secondaryHeaderOffset = -1; // A bogus value to catch bugs
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m_exeType = exeType_Invalid;
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if ( FALSE == MEMORY_MAPPED_FILE::IsValid() )
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return; // m_errorType already set to errEXE_FILE_FILE_NOT_FOUND
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// If we get here, the file exists, and was mapped. We're still not
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// sure that it's a valid EXE though
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m_errorType = errEXE_FILE_INVALID_FORMAT;
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if ( GetFileSize() < sizeof(IMAGE_DOS_HEADER) )
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return;
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PIMAGE_DOS_HEADER pDosHdr = (PIMAGE_DOS_HEADER)GetBase();
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if ( IMAGE_DOS_SIGNATURE != pDosHdr->e_magic )
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return;
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// If we get here, it's at least a DOS 'MZ' file
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m_errorType = errEXE_FILE_NO_ERROR;
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if ( pDosHdr->e_lfarlc < 0x40 ) // Theoretically, this field must be >=
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{ // 0x40 for it to be a non-DOS executable
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m_exeType = exeType_DOS;
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return;
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}
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// Sanity check. Make sure the "new header" offset isn't past the end
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// of the file
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if ( pDosHdr->e_lfanew > (LONG)GetFileSize() )
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return;
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// Make a pointer to the secondary header
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m_secondaryHeaderOffset = pDosHdr->e_lfanew;
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PWORD pSecondHdr = MakePtr( PWORD, GetBase(), m_secondaryHeaderOffset );
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// Decide what type of EXE, based on the start of the secondary header
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switch ( *pSecondHdr )
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{
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case IMAGE_OS2_SIGNATURE: m_exeType = exeType_NE; break;
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case IMAGE_VXD_SIGNATURE: m_exeType = exeType_VXD; break;
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case 0x4558: m_exeType = exeType_LX; break; // OS/2 2.X
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}
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if ( *(PDWORD)pSecondHdr == IMAGE_NT_SIGNATURE )
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m_exeType = exeType_PE;
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}
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PSTR EXE_FILE::GetFileTypeDescription( void )
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{
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// Returns a static string that describes what type this file is
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switch ( m_exeType )
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{
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case exeType_DOS: return "DOS";
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case exeType_NE: return "NE";
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case exeType_VXD: return "VXD";
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case exeType_LX: return "LX";
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case exeType_PE: return "PE";
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default: return "Invalid";
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}
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}
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