X-Git-Url: https://git.alrj.org/?p=bold.git;a=blobdiff_plain;f=Bold%2Felf.py;fp=Bold%2Felf.py;h=065be520712b15deec3781cd590f139f5209539f;hp=0000000000000000000000000000000000000000;hb=7eeaa837d3a6f29f9312bf29962214e709663e52;hpb=aa036795cb0ab7f31b9d78cfa562ccb603bc977a

diff --git a/Bold/elf.py b/Bold/elf.py
new file mode 100644
index 0000000..065be52
--- /dev/null
+++ b/Bold/elf.py
@@ -0,0 +1,867 @@
+# -*- coding: utf-8 -*-
+
+# kate: space-indent on; indent-width 2; mixedindent off; indent-mode python;
+
+# Copyright (C) 2009 Amand 'alrj' Tihon <amand.tihon@alrj.org>
+#
+# This file is part of bold, the Byte Optimized Linker.
+#
+# You can redistribute this file and/or modify it under the terms of the
+# GNU Lesser General Public License as published by the Free Software
+# Foundation, version 2.1.
+
+
+from BinArray import BinArray
+from constants import *
+from errors import *
+import struct
+
+# Helpful decorator
+def nested_property(c):
+  return property(**c())
+
+#--------------------------------------------------------------------------
+#  Elf
+#--------------------------------------------------------------------------
+
+class Elf64(object):
+  """Handles an Elf64 object."""
+  interpreter = "/lib64/ld-linux-x86-64.so.2"
+
+  def __init__(self, path=None):
+    object.__init__(self)
+    self.header = Elf64_Ehdr()
+    self.header.owner = self
+    self.shdrs = []
+    self.phdrs = []
+    self.shlibs = []
+    self.sections = {}
+    self.segments = []
+    self.local_symbols = {}
+    self.global_symbols = {}
+    self.undefined_symbols = []
+
+    if path:
+      self.fromfile(path)
+
+  # Functions for relocatables files used as input
+
+  def fromfile(self, path):
+    f = file(path, "rb")
+
+    # Load Elf header
+    data = BinArray()
+    data.fromfile(f, Elf64_Ehdr.size)
+    self.header.fromBinArray(data)
+
+    # This linker only supports relocatable objects
+    if self.header.e_type != ET_REL:
+      raise NotRelocatableObject(path)
+
+    if self.header.e_ident.ei_class != ELFCLASS64:
+      raise UnsupportedObject(path, "Not %s" % ELFCLASS64)
+
+    if self.header.e_machine != EM_X86_64:
+      raise UnsupportedObject(path, "Not %s" % EM_X86_64)
+
+    # Load sections headers
+    f.seek(self.header.e_shoff)
+    for i in range(self.header.e_shnum):
+      data = BinArray()
+      data.fromfile(f, self.header.e_shentsize)
+      h = Elf64_Shdr(i, data)
+      h.owner = self
+      self.shdrs.append(h)
+
+    # Read sections content
+    for sh in self.shdrs:
+      data = BinArray()
+      if sh.sh_type != SHT_NOBITS:
+        f.seek(sh.sh_offset)
+        data.fromfile(f, sh.sh_size)
+      sh.content = data
+
+    f.close()
+
+  def resolve_names(self):
+    # The .shstrtab index is in Elf Header. find the sections names
+    strtab = self.shdrs[self.header.e_shstrndx].content
+
+    for sh in self.shdrs:
+      sh.name = strtab[int(sh.sh_name)]
+      self.sections[sh.name] = sh
+
+      # And resolve names in the section itself
+      sh.resolve_names()
+
+
+  def find_symbols(self):
+    for sh in self.shdrs:
+      if sh.sh_type == SHT_SYMTAB:
+        symtab = sh.content.symtab
+
+        for symbol in symtab:
+          if symbol.st_type == STT_FILE:
+            continue
+          if symbol.st_shndx == SHN_ABS:
+            continue
+          if symbol.st_shndx == SHN_UNDEF:
+            if symbol.name:
+              self.undefined_symbols.append(symbol.name)
+            continue
+
+          target_section = self.shdrs[symbol.st_shndx]
+
+          symbol_name = symbol.name
+          value = symbol.st_value
+          bind = symbol.st_binding
+
+          # We got a name, a target section, and an offset in the section
+          if symbol.st_binding == STB_LOCAL:
+            if symbol.st_type == STT_SECTION:
+              symbol_name = target_section.name
+            self.local_symbols[symbol_name] = (target_section, value)
+          else:
+            self.global_symbols[symbol_name] = (target_section, value)
+
+  def apply_relocation(self, all_global_symbols):
+    # find relocation tables
+    relocations = [sh for sh in self.shdrs if sh.sh_type in [SHT_REL, SHT_RELA]]
+    for sh in relocations:
+      target = sh.target.content
+
+      for reloc in sh.content.relatab:
+        
+        if reloc.symbol.st_shndx == SHN_UNDEF:
+          # This is an extern symbol, find it in all_global_symbols
+          sym_address = all_global_symbols[reloc.symbol.name]
+        else:
+          # source == in which section it is defined
+          source = self.shdrs[reloc.symbol.st_shndx].content
+          sym_address = source.virt_addr + reloc.symbol.st_value
+
+        target_ba = target.data # The actual BinArray that we'll modify
+        pc_address = target.virt_addr + reloc.r_offset
+
+        if reloc.r_type == R_X86_64_64:
+          format = "<Q" # Direct 64 bit address
+          target_value = sym_address + reloc.r_addend
+        elif reloc.r_type == R_X86_64_PC32:
+          format = "<i" # PC relative 32 bit signed
+          target_value = sym_address + reloc.r_addend - pc_address
+        elif reloc.r_type == R_X86_64_32:
+          format = "<I" # Direct 32 bit zero extended
+          target_value = sym_address + reloc.r_addend
+        elif reloc.r_type == R_X86_64_PC16:
+          format = "<h" # 16 bit sign extended pc relative
+          target_value = sym_address + reloc.r_addend - pc_address
+        elif reloc.r_type == R_X86_64_16:
+          format = "<H" # Direct 16 bit zero extended
+          target_value = sym_address + reloc.r_addend
+        elif reloc.r_type == R_X86_64_PC8:
+          format = "b" # 8 bit sign extended pc relative
+          target_value = sym_address + reloc.r_addend - pc_address
+        elif reloc.r_type == R_X86_64_8:
+          format = "b" # Direct 8 bit sign extended
+          target_value = sym_address + reloc.r_addend
+        else:
+          print "Unsupported relocation type: %s" % reloc.r_type
+          exit(1)
+
+        d = BinArray(struct.pack(format, target_value))
+        start = reloc.r_offset
+        end = start + len(d)
+        target_ba[start:end] = d
+
+
+  # Functions for executables files, as output
+
+  def add_phdr(self, phdr):
+    self.phdrs.append(phdr)
+    self.header.e_phnum = len(self.phdrs)
+    phdr.owner = self
+
+  def add_segment(self, segment):
+    self.segments.append(segment)
+
+  def layout(self, base_vaddr):
+    """Do the actual layout for final executable."""
+
+    virt_addr = base_vaddr
+    file_offset = 0
+    self.virt_addr = base_vaddr
+    self.file_offset = file_offset
+    for s in self.segments:
+        virt_addr += s.align
+        s.virt_addr = virt_addr
+        s.file_offset = file_offset
+        s.layout()
+        virt_addr += s.logical_size
+        file_offset += s.physical_size
+
+  def toBinArray(self):
+    ba = BinArray()
+    for s in self.segments:
+      ba.extend(s.toBinArray())
+    return ba
+
+
+#--------------------------------------------------------------------------
+#  Elf file header
+#--------------------------------------------------------------------------
+
+class Elf64_eident(object):
+  """Detailed representation for the Elf identifier."""
+  format = "16B"
+  size = struct.calcsize(format)
+  physical_size = size
+  logical_size = size
+
+  def __init__(self, rawdata=None):
+    object.__init__(self)
+    if rawdata is not None:
+      self.fromBinArray(rawdata)
+
+  def fromBinArray(self, rawdata):
+    t = struct.unpack(self.format, rawdata)
+    self.ei_magic = rawdata[:4]
+    self.ei_class = ElfClass(rawdata[4])
+    self.ei_data = ElfData(rawdata[5])
+    self.ei_version = ElfVersion(rawdata[6])
+    self.ei_osabi = ElfOsAbi(rawdata[7])
+    self.ei_abiversion = 0
+    self.ei_pad = [0, 0, 0, 0, 0, 0, 0]
+
+  def make_default_amd64(self):
+    self.ei_magic = BinArray([0x7f, 0x45, 0x4c, 0x46])
+    self.ei_class = ELFCLASS64
+    self.ei_data = ELFDATA2LSB
+    self.ei_version = EV_CURRENT
+    self.ei_osabi = ELFOSABI_SYSV
+    self.ei_abiversion = 0
+    self.ei_pad = [0, 0, 0, 0, 0, 0, 0]
+
+  def toBinArray(self):
+    ba = BinArray(self.ei_magic)
+    ba.append(self.ei_class)
+    ba.append(self.ei_data)
+    ba.append(self.ei_version)
+    ba.append(self.ei_osabi)
+    ba.append(self.ei_abiversion)
+    ba.extend(self.ei_pad)
+    return ba
+
+
+class Elf64_Ehdr(object):
+  """Elf file header"""
+  format = "<16B 2H I 3Q I 6H"
+  size = struct.calcsize(format)
+  physical_size = size
+  logical_size = size
+  
+  def __init__(self, rawdata=None):
+    object.__init__(self)
+    self.e_ident = Elf64_eident()
+    self.e_type = ET_NONE
+    self.e_machine = EM_X86_64
+    self.e_version = EV_CURRENT
+    self.e_entry = 0
+    self.e_phoff = 0
+    self.e_shoff = 0
+    self.e_flags = 0
+    self.e_ehsize = self.size
+    self.e_phentsize = Elf64_Phdr.size
+    self.e_phnum = 0
+    self.e_shentsize = Elf64_Shdr.size
+    self.e_shnum = 0
+    self.e_shstrndx = 0
+    if rawdata is not None:
+      self.fromBinArray(rawdata)
+
+  def fromBinArray(self, rawdata):
+    t = struct.unpack(self.format, rawdata)
+    self.e_ident = Elf64_eident(BinArray(rawdata[:16]))
+    self.e_type = ElfType(t[16])
+    self.e_machine = ElfMachine(t[17])
+    self.e_version = ElfVersion(t[18])
+    self.e_entry = t[19]
+    self.e_phoff = t[20]
+    self.e_shoff = t[21]
+    self.e_flags = t[22]
+    self.e_ehsize = t[23]
+    self.e_phentsize = t[24]
+    self.e_phnum = t[25]
+    self.e_shentsize = t[26]
+    self.e_shnum = t[27]
+    self.e_shstrndx = t[28]
+
+  def toBinArray(self):
+    # Build a list from e_ident and all other fields, to feed struct.pack.
+    values = self.e_ident.toBinArray().tolist()
+    values.extend([self.e_type, self.e_machine, self.e_version, self.e_entry,
+      self.e_phoff, self.e_shoff, self.e_flags, self.e_ehsize, self.e_phentsize,
+      self.e_phnum, self.e_shentsize, self.e_shnum, self.e_shstrndx])
+    res = struct.pack(self.format, *values)
+    return BinArray(res)
+
+  def layout(self):
+    pass
+
+
+#--------------------------------------------------------------------------
+#  Elf Sections
+#--------------------------------------------------------------------------
+
+class Elf64_Shdr(object):
+  """Elf64 section header."""
+  format = "<2I 4Q 2I 2Q"
+  size = struct.calcsize(format)
+  physical_size = size
+  logical_size = size
+  
+  def __init__(self, index=None, rawdata=None):
+    object.__init__(self)
+    self.index = index
+    if rawdata is not None:
+      self.fromBinArray(rawdata)
+
+  def fromBinArray(self, rawdata):
+    t = struct.unpack(self.format, rawdata)
+    self.sh_name = t[0]
+    self.sh_type = ElfShType(t[1])
+    self.sh_flags = t[2]
+    self.sh_addr = t[3]
+    self.sh_offset = t[4]
+    self.sh_size = t[5]
+    self.sh_link = t[6]
+    self.sh_info = t[7]
+    self.sh_addralign = t[8]
+    self.sh_entsize = t[9]
+
+  def resolve_names(self):
+    self.content.resolve_names(self.owner)
+
+  @nested_property
+  def content():
+    def fget(self):
+      return self._content
+    def fset(self, data):
+      """Use the Section factory to get the subclass corresponding to the
+         session type specified in this header)."""
+      self._content = Section(self, data)
+    return locals()
+
+# For sections that contain elements of specific types :
+
+class Elf64_Sym(object):
+  """Symbol Table entry"""
+  format = "<I 2B H 2Q "
+  entsize = struct.calcsize(format)
+  def __init__(self, rawdata=None):
+    object.__init__(self)
+    if rawdata is not None:
+      self.fromBinArray(rawdata)
+
+  @nested_property
+  def st_binding():
+    def fget(self):
+      return ElfSymbolBinding((self.st_info >> 4) & 0x0f)
+    def fset(self, value):
+      self.st_info = (((value & 0x0f) << 4) | (self.st_info & 0x0f))
+    return locals()
+
+  @nested_property
+  def st_type():
+    def fget(self):
+       return ElfSymbolType(self.st_info & 0x0f)
+    def fset(self, value):
+      self.st_info = ((self.st_info & 0xf0) | (value & 0x0f))
+    return locals()
+
+  @nested_property
+  def st_visibility():
+    def fget(self):
+      return ElfSymbolVisibility(self.st_other & 0x03)
+    def fset(self, value):
+      self.st_other = ((self.st_other & 0xfc) | (value & 0x03))
+    return locals()
+
+  def fromBinArray(self, rawdata):
+    t = struct.unpack(self.format, rawdata)
+    self.st_name = t[0] # index in the strtab pointed by sh_link
+    self.st_info = t[1]
+    self.st_other = t[2]
+    self.st_shndx = ElfSectionIndex(t[3])
+    self.st_value = t[4]
+    self.st_size = t[5]
+
+
+class Elf64_Rel(object):
+  format = "<2Q"
+  def __init__(self, rawdata=None):
+    object.__init__(self)
+    self.r_addend = 0 # No addend in a Rel.
+    if rawdata is not None:
+      self.fromBinArray(rawdata)
+
+  def fromBinArray(sef, rawdata):
+    t = struct.unpack(self.format, rawdata)
+    self.r_offset = t[0]
+    self.r_info = t[1]
+
+  @nested_property
+  def r_sym():
+    def fget(self):
+      return (self.r_info >> 32) & 0xffffffff
+    def fset(self, value):
+      self.r_info = ((value & 0xffffffff) << 32) | (self.r_info & 0xffffffff)
+    return locals()
+
+  @nested_property
+  def r_type():
+    def fget(self):
+      return Amd64Relocation(self.r_info & 0xffffffff)
+    def fset(self, value):
+      self.r_info = (self.r_info & 0xffffffff00000000) | (value & 0xffffffff)
+    return locals()
+
+
+class Elf64_Rela(Elf64_Rel):
+  format = "<2Q q"
+  def __init__(self, rawdata=None):
+    Elf64_Rel.__init__(self, rawdata)
+
+  def fromBinArray(self, rawdata):
+    t = struct.unpack(self.format, rawdata)
+    self.r_offset = t[0]
+    self.r_info = t[1]
+    self.r_addend = t[2]
+
+
+class Elf64_Dyn(object):
+  format = "<2Q"
+  size = struct.calcsize(format)
+  def __init__(self, tag, value):
+    object.__init__(self)
+    self.d_tag = tag
+    self.d_val = value
+
+  @nested_property
+  def d_ptr():
+    def fget(self):
+      return self.d_val
+    def fset(self, value):
+      self.d_val = value
+    return locals()
+
+  def toBinArray(self):
+    ba = BinArray()
+    ba.fromstring(struct.pack(self.format, self.d_tag, self.d_val))
+    return ba
+
+# Sections types :
+
+def Section(shdr, data=None):
+  """A section factory"""
+  dataclass = {
+    SHT_NULL:           SNull,
+    SHT_PROGBITS:       SProgBits,
+    SHT_SYMTAB:         SSymtab,
+    SHT_STRTAB:         SStrtab,
+    SHT_RELA:           SRela,
+    SHT_HASH:           SHash,
+    SHT_DYNAMIC:        SDynamic,
+    SHT_NOTE:           SNote,
+    SHT_NOBITS:         SNobits,
+    SHT_REL:            SRel,
+    SHT_SHLIB:          SShlib,
+    SHT_DYNSYM:         SDynsym
+  }
+  if shdr.sh_type in dataclass:
+    return dataclass[shdr.sh_type](shdr, data)
+  else:
+    return BaseSection(shdr, data)
+
+
+class BaseSection(object):
+  def __init__(self, shdr, rawdata=None):
+    object.__init__(self)
+    self.data = None
+    self.header = shdr
+    if rawdata is not None:
+      self.fromBinArray(rawdata)
+
+  def fromBinArray(self, rawdata):
+    self.data = rawdata
+
+  def toBinArray(self):
+    if self.data:
+      return self.data
+    else:
+      return BinArray()
+
+  def resolve_names(self, elf):
+    """Nothing to resolve."""
+    pass
+
+  @nested_property
+  def size():
+    def fget(self):
+      return len(self.data)
+    return locals()
+  physical_size = size
+  logical_size = size
+
+  def layout(self):
+    pass
+
+
+class SNull(BaseSection):
+  def __init__(self, shdr, data=None):
+    BaseSection.__init__(self, shdr, None)
+
+
+class SProgBits(BaseSection):
+  def __init__(self, shdr, data=None):
+    BaseSection.__init__(self, shdr, data)
+
+
+class SSymtab(BaseSection):
+  entsize = struct.calcsize(Elf64_Sym.format)
+  def __init__(self, shdr, data=None):
+    self.symtab = []
+    BaseSection.__init__(self, shdr, data)
+
+  def fromBinArray(self, data):
+    BaseSection.fromBinArray(self, data)
+    nument = len(data) / self.entsize
+    for i in range(nument):
+      start = i * self.entsize
+      end = i * self.entsize + self.entsize
+      self.symtab.append(Elf64_Sym(data[start:end]))
+
+  def resolve_names(self, elf):
+    # For a symtab, the strtab is indicated by sh_link
+    strtab = elf.shdrs[self.header.sh_link].content
+    # Resolve for all symbols in the table
+    for sym in self.symtab:
+      sym.name = strtab[sym.st_name]
+
+  def __getitem__(self, key):
+    return self.symtab[key]
+
+
+class SStrtab(BaseSection):
+  """This one behaves in two completely different ways.
+  If it's given a section header and data, it will act as read-only, only to
+  be used for name resolution.
+  If it's not given any argument, it can be used to create a new Strtab."""
+  def __init__(self, shdr=None, data=None):
+    self.readonly = (shdr is not None)
+    self.strtab = {}
+    self.table = []
+    BaseSection.__init__(self, shdr, data)
+    self.virt_addr = None
+
+  def toBinArray(self):
+    if self.readonly:
+      return BaseSection.toBinArray()
+
+    ba = BinArray()
+    keys = self.strtab.keys()
+    keys.sort()
+    for k in keys:
+      ba.fromstring(self.strtab[k] + "\0")
+    return ba
+
+  @nested_property
+  def size():
+    def fget(self):
+      if self.readonly:
+        return len(data)
+      if len(self.strtab) == 0:
+        return 0
+      return sum((len(x)+1 for x in self.strtab.values()))
+    return locals()
+  physical_size = size
+  logical_size = size
+
+  def iteritems(self):
+    return self.strtab.iteritems()
+
+  # Resolution functions
+
+  def fromBinArray(self, data):
+    BaseSection.fromBinArray(self, data)
+    itab = data.tostring().split('\0')
+    i = 0
+    for sname in itab:
+      self.strtab[i] = sname
+      i += len(sname) + 1
+
+  def __getitem__(self, key):
+    if key in self.strtab:
+      return self.strtab[key]
+    else:
+      v = self.data[key:].tostring().split('\0')[0]
+      self.strtab[key] = v
+      return v
+
+  # Executable creation functions
+
+  def append(self, string):
+    if len(self.strtab) == 0:
+      offset = 0
+    else:
+      last = max(self.strtab.keys())
+      offset = last + len(self.strtab[last]) + 1 # for the \0
+    self.strtab[offset] = string
+    return offset
+
+  def layout(self):
+    pass
+
+
+class SRela(BaseSection):
+  entsize = struct.calcsize(Elf64_Rela.format)
+  def __init__(self, shdr, data=None):
+    self.relatab = []
+    BaseSection.__init__(self, shdr, data)
+
+  def fromBinArray(self, data):
+    BaseSection.fromBinArray(self, data)
+    nument = len(data) / self.entsize
+    for i in range(nument):
+      start = i * self.entsize
+      end = i * self.entsize + self.entsize
+      self.relatab.append(Elf64_Rela(data[start:end]))
+
+  def resolve_names(self, elf):
+    """Badly named, this wil resolve to a symtab entry..."""
+    # sh_link leads to the symtab
+    self.symtab = elf.shdrs[self.header.sh_link].content
+    # sh_info links to the section on which the relocation applies
+    self.header.target = elf.shdrs[self.header.sh_info]
+    for r in self.relatab:
+      r.symbol = self.symtab[r.r_sym]
+
+
+
+class SHash(BaseSection):
+  pass
+
+
+class SDynamic(BaseSection):
+  pass
+
+
+class SNote(BaseSection):
+  pass
+
+
+class SNobits(BaseSection):
+  size = 0
+  physical_size = 0
+
+  @nested_property
+  def logical_size():
+    def fget(self):
+      return self.header.sh_size
+    return locals()
+
+  def toBinArray(self):
+    return BinArray()
+
+class SRel(BaseSection):
+  pass
+
+
+class SShlib(BaseSection):
+  pass
+
+
+class SDynsym(SSymtab):
+  pass
+
+
+class Elf64_Phdr(object):
+  format = "<2I 6Q"
+  size = struct.calcsize(format)
+  physical_size = size
+  logical_size = size
+
+  def __init__(self):
+    object.__init__(self)
+    self.p_type = PT_NULL
+    self.p_flags = PF_X + PF_W + PF_R
+    self.p_offset = 0
+    self.p_vaddr = 0
+    self.p_paddr = 0
+    self.p_filesz = 0
+    self.p_memsz = 0
+    self.p_align = 1
+
+  def toBinArray(self):
+    res = struct.pack(self.format, self.p_type, self.p_flags, self.p_offset,
+      self.p_vaddr, self.p_paddr, self.p_filesz, self.p_memsz, self.p_align)
+    return BinArray(res)
+
+  def layout(self):
+    pass
+
+  def update_from_content(self, content):
+    """ Update ofset, address and sizes.
+    After having applied layout(),the content knows all these values."""
+    self.p_offset = content.file_offset
+    self.p_vaddr = content.virt_addr
+    self.p_filesz = content.physical_size
+    self.p_memsz = content.logical_size
+
+
+class BaseSegment(object):
+  def __init__(self, align=0):
+    object.__init__(self)
+    self.align = align
+    self.content = []
+
+  def add_content(self, content):
+    self.content.append(content)
+
+  def toBinArray(self):
+    ba = BinArray()
+    for c in self.content:
+      ba.extend(c.toBinArray())
+    return ba
+
+  @nested_property
+  def size():
+    def fget(self):
+      return sum(c.size for c in self.content)
+    return locals()
+  physical_size = size
+  logical_size = size
+
+
+class TextSegment(BaseSegment):
+  def __init__(self, align=0):
+    BaseSegment.__init__(self, align)
+
+  def layout(self):
+    virt_addr = self.virt_addr
+    file_offset = self.file_offset
+    for i in self.content:
+      i.virt_addr = virt_addr
+      i.file_offset = file_offset
+      i.layout()
+      virt_addr += i.logical_size
+      file_offset += i.physical_size
+
+
+class DataSegment(BaseSegment):
+  def __init__(self, align=0):
+    BaseSegment.__init__(self, align)
+    self.nobits = []
+
+  def add_nobits(self, content):
+    self.nobits.append(content)
+
+  def layout(self):
+    virt_addr = self.virt_addr
+    file_offset = self.file_offset
+    for i in self.content:
+      i.virt_addr = virt_addr
+      i.file_offset = file_offset
+      i.layout()
+      virt_addr += i.logical_size
+      file_offset += i.physical_size
+    for i in self.nobits:
+      i.virt_addr = virt_addr
+      i.file_offset = 0
+      i.layout()
+      virt_addr += i.logical_size
+
+  @nested_property
+  def logical_size():
+    def fget(self):
+      return self.physical_size + sum(c.logical_size for c in self.nobits)
+    return locals()
+
+
+class Dynamic(object):
+  def __init__(self):
+    object.__init__(self)
+    self.dyntab = []
+    self.strtab = SStrtab()
+
+  @nested_property
+  def size():
+    def fget(self):
+      # End the table with a DT_NULL without associated value.
+      return (Elf64_Dyn.size * len(self.dyntab) + struct.calcsize("Q"))
+    return locals()
+  physical_size = size
+  logical_size = size
+
+  def add_shlib(self, shlib):
+    offset = self.strtab.append(shlib)
+    self.dyntab.append(Elf64_Dyn(DT_NEEDED, offset))
+
+  def add_symtab(self, vaddr):
+    self.dyntab.append(Elf64_Dyn(DT_SYMTAB, vaddr))
+
+  def add_debug(self):
+    self.dyntab.append(Elf64_Dyn(DT_DEBUG, 0))
+
+  def layout(self):
+    # Adjust the address of the strtab, if 
+    if self.strtab.virt_addr is None:
+      print "Ooops, strtab's address is not known yet. Aborting."
+      exit(1)
+    else:
+      self.dyntab.append(Elf64_Dyn(DT_STRTAB, self.strtab.virt_addr))
+
+  @nested_property
+  def dt_debug_address():
+    def fget(self):
+      for i, d in enumerate(self.dyntab):
+        if d.d_tag == DT_DEBUG:
+          return self.virt_addr + (i*d.size + (d.size/2))
+    return locals()
+
+
+  def toBinArray(self):
+    ba = BinArray()
+    for d in self.dyntab:
+      ba.extend(d.toBinArray())
+    null = struct.pack("<Q", DT_NULL)
+    ba.fromstring(null)
+    return ba
+
+
+class Interpreter(object):
+  default_interpreter = "/lib64/ld-linux-x86-64.so.2"
+
+  def __init__(self, interpreter=None):
+    object.__init__(self)
+    if interpreter:
+      self.interpreter = interpreter
+    else:
+      self.interpreter = self.default_interpreter
+
+  @nested_property
+  def size():
+    def fget(self):
+      # Null terminated
+      return len(self.interpreter) + 1
+    return locals()
+  physical_size = size
+  logical_size = size
+
+  def toBinArray(self):
+    ba = BinArray(self.interpreter)
+    ba.append(0)
+    return ba
+
+  def layout(self):
+    pass
+