DOSExe.cpp

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#include "pe/DOSExe.h"
 
 
bool DOSExeBuilder::signatureMatches(AbstractByteBuffer *buf)
{
    if (buf == NULL) return false;
 
    WORD *magic = (WORD*) buf->getContentAt(0, sizeof(WORD));
    if (magic == NULL) return false;
 
    if ((*magic) == pe::S_DOS || (*magic) == pe::S_DOS2) {
        return true;
    }
 
    return false;
}
 
Executable* DOSExeBuilder::build(AbstractByteBuffer *buf)
{
    Executable *exe = NULL;
    if (signatureMatches(buf) == false) return NULL;
 
    try {
        exe = new DOSExe(buf);
    } catch (ExeException) {
        //
    }
 
    return exe;
}
 
//-------------------------------------------------------------
 
DOSExe::DOSExe(AbstractByteBuffer *v_buf)
    : MappedExe(v_buf, Executable::BITS_16), dosHdrWrapper(NULL)
{
    wrap();
}
 
void DOSExe::wrap()
{
    this->dosHdrWrapper = new DosHdrWrapper(this);
 
    m_dosHdr = (IMAGE_DOS_HEADER*) getContentAt(0, sizeof(IMAGE_DOS_HEADER));
    if (m_dosHdr == NULL) throw ExeException("Could not Wrap!");
 
    WORD* magic = (WORD*) this->dosHdrWrapper->getFieldPtr(DosHdrWrapper::MAGIC);
 
    if (this->dosHdrWrapper->getPtr() == NULL || magic == NULL) {
        throw ExeException("Could not Wrap!");
    }
 
    if ((*magic) != pe::S_DOS && (*magic) != pe::S_DOS2) {
        Logger::append(Logger::D_WARNING, "It is not a DOS file!\n");
        throw ExeException("It is not a DOS file!");
    }
    this->wrappers[WR_DOS_HDR] = this->dosHdrWrapper;
}
 
offset_t DOSExe::peSignatureOffset()
{
    LONG* lfnew = (LONG*) this->dosHdrWrapper->getFieldPtr(DosHdrWrapper::LFNEW);
    if (lfnew == NULL) return 0;
 
    return static_cast<offset_t>(*lfnew);
}