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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 | import lldb from xnu import * _UnionStructClass = [ lldb.eTypeClassStruct, lldb.eTypeClassClass, lldb.eTypeClassUnion ] def _showStructPacking(O, symbol, begin_offset=0, symsize=0, typedef=None, outerSize=0, memberName=None): """ recursively parse the field members of structure. params : O the output formatter (standard.py) symbol (lldb.SBType) reference to symbol in binary returns: string containing lines of output. """ ctype = "unknown type" is_union = False is_class = False union_size = None sym_size = symbol.GetByteSize() if symbol.GetTypeClass() == lldb.eTypeClassUnion: ctype = "union" is_union = True union_size = sym_size if symbol.GetTypeClass() == lldb.eTypeClassStruct: ctype = "struct" if symbol.GetTypeClass() == lldb.eTypeClassClass: ctype = "class" is_class = True if not outerSize or outerSize == sym_size: outstr = O.format("{:04d},[{:4d}]", begin_offset, sym_size) elif outerSize < sym_size: # happens with c++ inheritance outstr = O.format("{:04d},[{:4d}]", begin_offset, outerSize) else: outstr = O.format("{:04d},[{:4d}]{VT.DarkRed}{{{:+d}}}{VT.Default}", begin_offset, sym_size, outerSize - sym_size) if typedef: outstr += O.format(" {0}", typedef) if symbol.IsAnonymousType(): outstr += O.format(" ({VT.DarkMagenta}anonymous {0}{VT.Default})", ctype) else: outstr += O.format(" ({VT.DarkMagenta}{0} {1}{VT.Default})", ctype, symbol.GetName()) if memberName: outstr += O.format(" {0} {{", memberName) else: outstr += ") {" print outstr with O.indent(): _previous_size = 0 _packed_bit_offset = 0 _nfields = symbol.GetNumberOfFields() if is_class: _next_offset_in_bits = 0 _nclasses = symbol.GetNumberOfDirectBaseClasses() for i in range(_nclasses): member = symbol.GetDirectBaseClassAtIndex(i) if i < _nclasses - 1: m_size_bits = symbol.GetDirectBaseClassAtIndex(i + 1).GetOffsetInBits() elif _nfields: m_size_bits = symbol.GetFieldAtIndex(0).GetOffsetInBits() else: m_size_bits = symbol.GetByteSize() * 8 m_offset = member.GetOffsetInBytes() + begin_offset m_type = member.GetType() m_name = member.GetName() m_size = m_size_bits / 8 _previous_size = m_size _packed_bit_offset = member.GetOffsetInBits() + m_size_bits _showStructPacking(O, m_type, m_offset, str(m_type), outerSize=m_size, memberName=m_name) for i in range(_nfields): member = symbol.GetFieldAtIndex(i) m_offset = member.GetOffsetInBytes() + begin_offset m_offset_bits = member.GetOffsetInBits() m_type = member.GetType() m_name = member.GetName() m_size = m_type.GetByteSize() if member.IsBitfield(): m_is_bitfield = True m_size_bits = member.GetBitfieldSizeInBits() else: m_is_bitfield = False m_size_bits = m_size * 8 if not is_union and _packed_bit_offset < m_offset_bits: m_previous_offset = begin_offset + _packed_bit_offset / 8 m_hole_bits = m_offset_bits - _packed_bit_offset if _packed_bit_offset % 8 == 0: print O.format("{:04d},[{:4d}] ({VT.DarkRed}*** padding ***{VT.Default})", m_previous_offset, m_hole_bits / 8) else: print O.format("{:04d},[{:4d}] ({VT.Brown}*** padding : {:d} ***{VT.Default})", m_previous_offset, _previous_size, m_hole_bits) _previous_size = m_size _packed_bit_offset = m_offset_bits + m_size_bits _type_class = m_type.GetTypeClass() _canonical_type = m_type.GetCanonicalType() _canonical_type_class = m_type.GetCanonicalType().GetTypeClass() if _type_class == lldb.eTypeClassTypedef and _canonical_type_class in _UnionStructClass: _showStructPacking(O, _canonical_type, m_offset, str(m_type), outerSize=union_size, memberName=m_name) elif _type_class in _UnionStructClass: _showStructPacking(O, m_type, m_offset, outerSize=union_size, memberName=m_name) else: outstr = O.format("{:04d},[{:4d}]", m_offset, m_size) if is_union and union_size != m_size_bits / 8: outstr += O.format("{VT.DarkRed}{{{:+d}}}{VT.Default}", union_size - m_size_bits / 8) if m_is_bitfield: outstr += O.format(" ({VT.DarkGreen}{:s} : {:d}{VT.Default}) {:s}", m_type.GetName(), m_size_bits, m_name) else: outstr += O.format(" ({VT.DarkGreen}{:s}{VT.Default}) {:s}", m_type.GetName(), m_name) print outstr referenceSize = min(outerSize, sym_size) or sym_size if not is_union and _packed_bit_offset < referenceSize * 8: m_previous_offset = begin_offset + _packed_bit_offset / 8 m_hole_bits = referenceSize * 8 - _packed_bit_offset offset = _packed_bit_offset / 8 + begin_offset if _packed_bit_offset % 8 == 0: print O.format("{:04d},[{:4d}] ({VT.DarkRed}*** padding ***{VT.Default})", m_previous_offset, m_hole_bits / 8) else: print O.format("{:04d},[{:4d}] ({VT.Brown}padding : {:d}{VT.Default})\n", m_previous_offset, _previous_size, m_hole_bits) print "}" @lldb_command('showstructpacking', fancy=True) def showStructInfo(cmd_args=None, cmd_options={}, O=None): """Show how a structure is packed in the binary. The format is <offset>, [<size_of_member>] (<type>) <name> For example: (lldb) showstructpacking pollfd 0,[ 8] struct pollfd { 0,[ 4] (int) fd 4,[ 2] (short) events 6,[ 2] (short) revents } syntax: showstructpacking task """ if not cmd_args: raise ArgumentError("Please provide a type name.") ty_name = cmd_args[0] try: sym = gettype(ty_name) except NameError: return O.error("Cannot find type named {0}", ty_name) if sym.GetTypeClass() == lldb.eTypeClassTypedef: sym = sym.GetCanonicalType() if sym.GetTypeClass() not in _UnionStructClass: return O.error("{0} is not a structure/union/class type", ty_name) _showStructPacking(O, sym, 0) # EndMacro: showstructinto |