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
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
|
#! /usr/bin/env python
from __future__ import print_function
import re
import struct
from miasm.core.utils import force_bytes
from future.utils import PY3, viewitems, with_metaclass
type2realtype = {}
size2type = {}
size2type_s = {}
for t in 'B', 'H', 'I', 'Q':
s = struct.calcsize(t)
type2realtype[t] = s * 8
size2type[s * 8] = t
for t in 'b', 'h', 'i', 'q':
s = struct.calcsize(t)
type2realtype[t] = s * 8
size2type_s[s * 8] = t
type2realtype['u08'] = size2type[8]
type2realtype['u16'] = size2type[16]
type2realtype['u32'] = size2type[32]
type2realtype['u64'] = size2type[64]
type2realtype['s08'] = size2type_s[8]
type2realtype['s16'] = size2type_s[16]
type2realtype['s32'] = size2type_s[32]
type2realtype['s64'] = size2type_s[64]
type2realtype['d'] = 'd'
type2realtype['f'] = 'f'
type2realtype['q'] = 'q'
type2realtype['ptr'] = 'ptr'
sex_types = {0: '<', 1: '>'}
def fix_size(fields, wsize):
out = []
for name, v in fields:
if v.endswith("s"):
pass
elif v == "ptr":
v = size2type[wsize]
elif not v in type2realtype:
raise ValueError("unknown Cstruct type", v)
else:
v = type2realtype[v]
out.append((name, v))
fields = out
return fields
def real_fmt(fmt, wsize):
if fmt == "ptr":
v = size2type[wsize]
elif fmt in type2realtype:
v = type2realtype[fmt]
else:
v = fmt
return v
all_cstructs = {}
class Cstruct_Metaclass(type):
field_suffix = "_value"
def __new__(cls, name, bases, dct):
for fields in dct['_fields']:
fname = fields[0]
if fname in ['parent', 'parent_head']:
raise ValueError('field name will confuse internal structs',
repr(fname))
dct[fname] = property(dct.pop("get_" + fname,
lambda self, fname=fname: getattr(
self, fname + self.__class__.field_suffix)),
dct.pop("set_" + fname,
lambda self, v, fname=fname: setattr(
self, fname + self.__class__.field_suffix, v)),
dct.pop("del_" + fname, None))
o = super(Cstruct_Metaclass, cls).__new__(cls, name, bases, dct)
if name != "CStruct":
all_cstructs[name] = o
return o
def unpack_l(cls, s, off=0, parent_head=None, _sex=None, _wsize=None):
if _sex is None and _wsize is None:
# get sex and size from parent
if parent_head is not None:
_sex = parent_head._sex
_wsize = parent_head._wsize
else:
_sex = 0
_wsize = 32
c = cls(_sex=_sex, _wsize=_wsize)
if parent_head is None:
parent_head = c
c.parent_head = parent_head
of1 = off
for field in c._fields:
cpt = None
if len(field) == 2:
fname, ffmt = field
elif len(field) == 3:
fname, ffmt, cpt = field
if ffmt in type2realtype or (isinstance(ffmt, str) and re.match(r'\d+s', ffmt)):
# basic types
if cpt:
value = []
i = 0
while i < cpt(c):
fmt = real_fmt(ffmt, _wsize)
of2 = of1 + struct.calcsize(fmt)
value.append(struct.unpack(c.sex + fmt, s[of1:of2])[0])
of1 = of2
i += 1
else:
fmt = real_fmt(ffmt, _wsize)
of2 = of1 + struct.calcsize(fmt)
if not (0 <= of1 < len(s) and 0 <= of2 < len(s)):
raise RuntimeError("not enough data")
value = struct.unpack(c.sex + fmt, s[of1:of2])[0]
elif ffmt == "sz": # null terminated special case
of2 = s.find(b'\x00', of1)
if of2 == -1:
raise ValueError('no null char in string!')
of2 += 1
value = s[of1:of2 - 1]
elif ffmt in all_cstructs:
of2 = of1
# sub structures
if cpt:
value = []
i = 0
while i < cpt(c):
v, l = all_cstructs[ffmt].unpack_l(
s, of1, parent_head, _sex, _wsize)
v.parent = c
value.append(v)
of2 = of1 + l
of1 = of2
i += 1
else:
value, l = all_cstructs[ffmt].unpack_l(
s, of1, parent_head, _sex, _wsize)
value.parent = c
of2 = of1 + l
elif isinstance(ffmt, tuple):
f_get, f_set = ffmt
value, of2 = f_get(c, s, of1)
else:
raise ValueError('unknown class', ffmt)
of1 = of2
setattr(c, fname + c.__class__.field_suffix, value)
return c, of2 - off
def unpack(cls, s, off=0, parent_head=None, _sex=None, _wsize=None):
c, l = cls.unpack_l(s, off=off,
parent_head=parent_head, _sex=_sex, _wsize=_wsize)
return c
class CStruct(with_metaclass(Cstruct_Metaclass, object)):
_packformat = ""
_fields = []
def __init__(self, parent_head=None, _sex=None, _wsize=None, **kargs):
self.parent_head = parent_head
self._size = None
kargs = dict(kargs)
# if not sex or size: get the one of the parent
if _sex == None and _wsize == None:
if parent_head:
_sex = parent_head._sex
_wsize = parent_head._wsize
else:
# else default sex & size
_sex = 0
_wsize = 32
# _sex is 0 or 1, sex is '<' or '>'
self._sex = _sex
self._wsize = _wsize
if self._packformat:
self.sex = self._packformat
else:
self.sex = sex_types[_sex]
for f in self._fields:
setattr(self, f[0] + self.__class__.field_suffix, None)
if kargs:
for k, v in viewitems(kargs):
self.__dict__[k + self.__class__.field_suffix] = v
def pack(self):
out = b''
for field in self._fields:
cpt = None
if len(field) == 2:
fname, ffmt = field
elif len(field) == 3:
fname, ffmt, cpt = field
value = getattr(self, fname + self.__class__.field_suffix)
if ffmt in type2realtype or (isinstance(ffmt, str) and re.match(r'\d+s', ffmt)):
# basic types
fmt = real_fmt(ffmt, self._wsize)
if cpt == None:
if value == None:
o = struct.calcsize(fmt) * b"\x00"
elif ffmt.endswith('s'):
new_value = force_bytes(value)
o = struct.pack(self.sex + fmt, new_value)
else:
o = struct.pack(self.sex + fmt, value)
else:
o = b""
for v in value:
if value == None:
o += struct.calcsize(fmt) * b"\x00"
else:
o += struct.pack(self.sex + fmt, v)
elif ffmt == "sz": # null terminated special case
o = value + b'\x00'
elif ffmt in all_cstructs:
# sub structures
if cpt == None:
o = bytes(value)
else:
o = b""
for v in value:
o += bytes(v)
elif isinstance(ffmt, tuple):
f_get, f_set = ffmt
o = f_set(self, value)
else:
raise ValueError('unknown class', ffmt)
out += o
return out
def __bytes__(self):
return self.pack()
def __str__(self):
if PY3:
return repr(self)
return self.__bytes__()
def __len__(self):
return len(self.pack())
def __repr__(self):
return "<%s=%s>" % (self.__class__.__name__, "/".join(
repr(getattr(self, x[0])) for x in self._fields)
)
def __getitem__(self, item): # to work with format strings
return getattr(self, item)
|