BinaryFileFactory.cpp

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/* File: BinaryFileFactory.cpp
 * Desc: This file contains the implementation of the factory function
 * BinaryFile::getInstanceFor(), and also BinaryFile::Load()
 * 
 * This function determines the type of a binary and loads the appropriate
 * loader class dynamically.
*/

#ifndef _WIN32
#include <dlfcn.h>
#else
#include <windows.h>            // include before types.h: name collision of NO_ADDRESS and WinSock.h
#endif

#include "BinaryFile.h"
#include "ElfBinaryFile.h"
#include "Win32BinaryFile.h"
#include "PalmBinaryFile.h"
#include "HpSomBinaryFile.h"
#include "ExeBinaryFile.h"
#include "config.h"             // For HOST_OSX_10_2 etc

#include <iostream>

BinaryFile *BinaryFileFactory::Load( const char *sName )
{
    BinaryFile *pBF = getInstanceFor( sName );
    if( pBF == NULL ) {
        std::cerr << "unrecognised binary file format.\n";
        return NULL;
    }
    if( pBF->RealLoad( sName ) == 0 ) {
        fprintf( stderr, "Loading '%s' failed\n", sName );
        delete pBF;
        return NULL;
    }
pBF->getTextLimits();
    return pBF;
}

#define TESTMAGIC2(buf,off,a,b)     (buf[off] == a && buf[off+1] == b)
#define TESTMAGIC4(buf,off,a,b,c,d) (buf[off] == a && buf[off+1] == b && \
                                     buf[off+2] == c && buf[off+3] == d)

// Declare a pointer to a constructor function; returns a BinaryFile*
typedef BinaryFile* (*constructFcn)();

BinaryFile* BinaryFileFactory::getInstanceFor( const char *sName ) {
    FILE *f;
    unsigned char buf[64];
    std::string libName;
    BinaryFile *res = NULL;

    f = fopen (sName, "rb");
    if( f == NULL ) {
        fprintf(stderr, "Unable to open binary file: %s\n", sName );
        return NULL;
    }
    fread (buf, sizeof(buf), 1, f);
    if( TESTMAGIC4(buf,0, '\177','E','L','F') ) {
        /* ELF Binary */
        libName = "ElfBinaryFile";
    } else if( TESTMAGIC2( buf,0, 'M','Z' ) ) { /* DOS-based file */
        int peoff = LMMH(buf[0x3C]);
        if( peoff != 0 && fseek(f, peoff, SEEK_SET) != -1 ) {
            fread( buf, 4, 1, f );
            if( TESTMAGIC4( buf,0, 'P','E',0,0 ) ) {
                /* Win32 Binary */
                libName = "Win32BinaryFile";
            } else if( TESTMAGIC2( buf,0, 'N','E' ) ) {
                /* Win16 / Old OS/2 Binary */
            } else if( TESTMAGIC2( buf,0, 'L','E' ) ) {
                /* Win32 VxD (Linear Executable) or DOS4GW app */
                libName = "DOS4GWBinaryFile";
            } else if( TESTMAGIC2( buf,0, 'L','X' ) ) {
                /* New OS/2 Binary */
            }
        }
        /* Assume MS-DOS Real-mode binary. */
        if( libName.size() == 0 )
            libName = "ExeBinaryFile";
    } else if( TESTMAGIC4( buf,0x3C, 'a','p','p','l' ) ||
               TESTMAGIC4( buf,0x3C, 'p','a','n','l' ) ) {
        /* PRC Palm-pilot binary */
        libName = "PalmBinaryFile";
    } else if( buf[0] == 0xfe && buf[1] == 0xed && buf[2] == 0xfa && buf[3] == 0xce ) {
        /* Mach-O Mac OS-X binary */
        libName = "MachOBinaryFile";
#ifdef __CYGWIN__
        fprintf(stderr, "Sorry, Cygwin-hosted Boomerang cannot compile the MachOBinaryFile module at present"
            "\n");
        fclose(f);
        return NULL;
#endif
    } else if( buf[0] == 0x02 && buf[2] == 0x01 &&
               (buf[1] == 0x10 || buf[1] == 0x0B) &&
               (buf[3] == 0x07 || buf[3] == 0x08 || buf[4] == 0x0B) ) {
        /* HP Som binary (last as it's not really particularly good magic) */
        libName = "HpSomBinaryFile";
    } else {
        fprintf( stderr, "Unrecognised binary file\n" );
        fclose(f);
        return NULL;
    }
    
// Load the specific loader library
#ifndef _WIN32      // Cygwin, Unix/Linux
    libName = std::string("lib/lib") + libName;
#ifdef  __CYGWIN__
    libName += ".dll";      // Cygwin wants .dll, but is otherwise like Unix
#else
#if HOST_OSX
    libName += ".dylib";
#else
    libName += ".so";
#endif
#endif
    dlHandle = dlopen(libName.c_str(), RTLD_LAZY);
    if (dlHandle == NULL) {
        fprintf( stderr, "Could not open dynamic loader library %s\n", libName.c_str());
        fprintf( stderr, "%s\n", dlerror());
        fclose(f);
        return NULL;
    }
    // Use the handle to find the "construct" function
#if 0   // HOST_OSX_10_2    // Not sure when the underscore is really needed
#define UNDERSCORE "_"      // Only OSX 10.2 seems to need this underscore
#else
#define UNDERSCORE
#endif
    constructFcn pFcn = (constructFcn) dlsym(dlHandle, UNDERSCORE "construct");
#else                       // Else MSVC, MinGW
    libName += ".dll";      // Example: ElfBinaryFile.dll (same dir as boomerang.exe)
#ifdef __MINGW32__
    libName = "lib/lib" + libName;
#endif
    hModule = LoadLibraryA(libName.c_str());
    if(hModule == NULL) {
        int err = GetLastError();
        fprintf( stderr, "Could not open dynamic loader library %s (error #%d)\n", libName.c_str(), err);
        fclose(f);
        return NULL;
    }
    // Use the handle to find the "construct" function
    constructFcn pFcn = (constructFcn) GetProcAddress((HINSTANCE)hModule, "construct");
#endif

    if (pFcn == NULL) {
        fprintf( stderr, "Loader library %s does not have a construct function\n", libName.c_str());
#ifndef _WIN32
        fprintf( stderr, "dlerror returns %s\n", dlerror());
#endif
        fclose(f);
        return NULL;
    }
    // Call the construct function
    res = (*pFcn)();
    fclose(f);
    return res;
}

void BinaryFileFactory::UnLoad() {
#ifdef _WIN32
    FreeLibrary((HINSTANCE)hModule);
#else
    dlclose(dlHandle);                  // Especially important for Mac OS X
#endif
}

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