Class: Resedit::MZHeader

Inherits:
ExeHeader show all
Defined in:
lib/resedit/mz/mz.rb

Constant Summary collapse

MAGIC = 
0x5A4D
HSIZE = 
0x1C
HDRDESCR = 
[:Magic, :BytesInLastBlock, :BlocksInFile, :NumberOfRelocations, :HeaderParagraphs, :MinExtraParagraphs, :MaxExtraParagraphs,
:SS, :SP, :Checksum, :IP, :CS, :RelocTableOffset, :OverlayNumber]

Constants inherited from ExeHeader

ExeHeader::BLK, ExeHeader::HDRUNPACK, ExeHeader::PARA

Constants inherited from Changeable

Changeable::COL_CHANGED, Changeable::COL_ORIGINAL, Changeable::HOW_CHANGED, Changeable::HOW_ORIGINAL, Changeable::LOG

Instance Attribute Summary collapse

Attributes inherited from ExeHeader

#exe, #info

Instance Method Summary collapse

Methods inherited from ExeHeader

#_headerTable, #change, #fieldOffset, #fieldSize, #loadInfo, #loadTables, #loadTail, #mode, #setBodySize, #setHeaderSize, #setInfo

Methods inherited from Changeable

#addData, #bytes, #change, #changed?, #colStr, #colVal, #curcol, #dbgdump, #debug, #fix, #getChanges, #getData, #hex, #hexify, #insert, #mode, #parseHow, #revert, #saveChanges, #saveData, #setData, #size, #undo, #unhexify

Constructor Details

#initialize(exe, file, size) ⇒ MZHeader

Returns a new instance of MZHeader.



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# File 'lib/resedit/mz/mz.rb', line 13

def initialize(exe, file, size)
    super(exe, file, size)
    @fsize = size
    @relocFix = 0
    @newOfs = false
    if @info[:RelocTableOffset]>=0x40
        @newOfs = getData(0x3C, 2).unpack("v")[0]
    end
end

Instance Attribute Details

#relocFix ⇒ Object (readonly)

Returns the value of attribute relocFix.



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# File 'lib/resedit/mz/mz.rb', line 11

def relocFix
  @relocFix
end

Instance Method Details

#addHeaderSize(size) ⇒ Object 



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# File 'lib/resedit/mz/mz.rb', line 52

def addHeaderSize(size)
    mode(HOW_CHANGED)
    paras = size/16 + (size%16 == 0 ? 0 : 1)
    insert(headerSize(), "\x00" * (paras * PARA))
    setFileSize(fileSize() + paras * PARA)
    setInfo(:HeaderParagraphs, @info[:HeaderParagraphs] + paras)
    mode(HOW_CHANGED)
end

#addReloc(ofs, trg) ⇒ Object 



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# File 'lib/resedit/mz/mz.rb', line 107

def addReloc(ofs, trg)
    mode(HOW_CHANGED)
    #check relocation exists
    for i in 0..@info[:NumberOfRelocations]-1
        rel = getRelocation(i)
        return false if @exe.body.seg2Linear(rel[0], rel[1]) == ofs
    end
    #add relocation
    rid = @info[:NumberOfRelocations]
    setSpaceForRelocs(@info[:NumberOfRelocations]+1)
    val = @exe.body.linear2seg(ofs)
    setRelocation(rid, val)
    return true
end

#entry ⇒ Object 



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# File 'lib/resedit/mz/mz.rb', line 23

def entry; sprintf("%04X:%04X", @info[:CS], @info[:IP]) end

#fileSize ⇒ Object 



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# File 'lib/resedit/mz/mz.rb', line 72

def fileSize()
    return @newOfs if @newOfs
    sz = @info[:BlocksInFile] * BLK
    if @info[:BytesInLastBlock] != 0
        sz -= BLK - @info[:BytesInLastBlock]
    end
    return sz
end

#freeSpace(middle = false) ⇒ Object 



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# File 'lib/resedit/mz/mz.rb', line 93

def freeSpace(middle = false)
    return @info[:RelocTableOffset] - HSIZE  if middle
    return headerSize() - HSIZE - @info[:NumberOfRelocations] * 4
end

#getRelocation(idx) ⇒ Object 



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# File 'lib/resedit/mz/mz.rb', line 82

def getRelocation(idx)
    raise "Wrong relocation index " if idx<0 || idx >= @info[:NumberOfRelocations]
    return getData(@info[:RelocTableOffset] + idx * 4, 4).unpack('vv')
end

#headerSize ⇒ Object 



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# File 'lib/resedit/mz/mz.rb', line 70

def headerSize(); @info[:HeaderParagraphs] * PARA end

#loadChanges(cfg) ⇒ Object 



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# File 'lib/resedit/mz/mz.rb', line 61

def loadChanges(cfg)
    super(cfg)
    mode(HOW_ORIGINAL)
    ocs = @info[:CS]
    mode(HOW_CHANGED)
    ncs = @info[:CS]
    @relocFix = ncs - ocs
end

#print(what, how) ⇒ Object 



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# File 'lib/resedit/mz/mz.rb', line 122

def print(what, how)
    mode(parseHow(how))
    if what == "header"
        ofs=0
        @info.each{|k,v|
            printf("%20s:\t%s\n", k.to_s, colVal(ofs, 2))
            ofs+=2
        }
        puts
        fsz = fileSize()
        hsz = headerSize()
        s = colStr(sprintf("%d (%X)", fsz,fsz), changed?(2, 4))
        printf("mz file size: %s\treal file size: %d (0x%X)\n", s, @fsize, @fsize)
        printf("header size: %s\n", colStr(hsz, changed?(8, 2)))
        printf("code size: %s\n", colStr(fsz - hsz, @exe.body.changed?(0)))
        printf("reloc table size: %s\n", colStr(@info[:NumberOfRelocations] * 4, changed?(6, 2)))
        printf("free space in header: before relocs 0x%X,  after relocs 0x%X\n", freeSpace(true), freeSpace())
        printf("reloc fix: 0x%X\n", @relocFix)
        return true
    end
    @exe.body.mode(@mode)
    if what == "reloc"
        ofs = @info[:RelocTableOffset]
        for i in 0..@info[:NumberOfRelocations]-1
            s1 = colVal(ofs,2)
            s2 = colVal(ofs+2,2)
            s3 = @exe.body.segData(getRelocation(i), 2, true)
            printf("%08X\t%s:%s\t= %s\n", ofs, s2, s1, s3)
            ofs += 4
        end
        return true
    end
    return super(what, how)
end

#rebuildHeader(codesize) ⇒ Object 



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# File 'lib/resedit/mz/mz.rb', line 31

def rebuildHeader(codesize)
    mode(HOW_ORIGINAL)
    ss = @info[:SS]
    cs = @info[:CS]
    sz = fileSize()-headerSize()
    codesize += PARA - codesize % PARA if codesize % PARA!=0
    setFileSize(sz + codesize + headerSize())
    paras = codesize / PARA
    setInfo(:SS, ss+paras)
    setInfo(:CS, cs+paras)
    for i in 0..@info[:NumberOfRelocations]-1
        rel = getRelocation(i)
        rel[1] += paras-@relocFix
        fix(@info[:RelocTableOffset] + i * 4, rel.pack('vv'))
    end
    mode(HOW_CHANGED)
    @relocFix = paras
    @exe.env.set(:relocFix, paras.to_s)
    return codesize
end

#setFileSize(size) ⇒ Object 



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# File 'lib/resedit/mz/mz.rb', line 25

def setFileSize(size)
    mode(HOW_CHANGED)
    mod = size % BLK
    setInfo(:BytesInLastBlock, [mod, size / BLK + (mod ? 1 : 0)])
end

#setRelocation(idx, data) ⇒ Object 



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# File 'lib/resedit/mz/mz.rb', line 87

def setRelocation(idx, data)
    raise "Wrong relocation index " if idx<0 || idx >= @info[:NumberOfRelocations]
    change(@info[:RelocTableOffset] + idx * 4, data.pack('vv'))
end

#setSpaceForRelocs(count) ⇒ Object 



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# File 'lib/resedit/mz/mz.rb', line 98

def setSpaceForRelocs(count)
    add = count - @info[:NumberOfRelocations]
    return if add<=0
    add -= freeSpace()/4
    addHeaderSize(add*4) if add>0
    setInfo(:NumberOfRelocations, count)
    mode(HOW_CHANGED)
end