lldb/examples/python/file_extract.py

   1 #!/usr/bin/env python
   2
   3 import string
   4 import struct
   5 import sys
   6
   7
   8 class FileExtract:
   9     """Decode binary data from a file"""
  10
  11     def __init__(self, f, b="="):
  12         """Initialize with an open binary file and optional byte order"""
  13
  14         self.file = f
  15         self.byte_order = b
  16         self.offsets = list()
  17
  18     def set_byte_order(self, b):
  19         '''Set the byte order, valid values are "big", "little", "swap", "native", "<", ">", "@", "="'''
  20         if b == "big":
  21             self.byte_order = ">"
  22         elif b == "little":
  23             self.byte_order = "<"
  24         elif b == "swap":
  25             # swap what ever the current byte order is
  26             self.byte_order = swap_unpack_char()
  27         elif b == "native":
  28             self.byte_order = "="
  29         elif b == "<" or b == ">" or b == "@" or b == "=":
  30             self.byte_order = b
  31         else:
  32             print("error: invalid byte order specified: '%s'" % b)
  33
  34     def is_in_memory(self):
  35         return False
  36
  37     def seek(self, offset, whence=0):
  38         if self.file:
  39             return self.file.seek(offset, whence)
  40         raise ValueError
  41
  42     def tell(self):
  43         if self.file:
  44             return self.file.tell()
  45         raise ValueError
  46
  47     def read_size(self, byte_size):
  48         s = self.file.read(byte_size)
  49         if len(s) != byte_size:
  50             return None
  51         return s
  52
  53     def push_offset_and_seek(self, offset):
  54         '''Push the current file offset and seek to "offset"'''
  55         self.offsets.append(self.file.tell())
  56         self.file.seek(offset, 0)
  57
  58     def pop_offset_and_seek(self):
  59         """Pop a previously pushed file offset, or do nothing if there were no previously pushed offsets"""
  60         if len(self.offsets) > 0:
  61             self.file.seek(self.offsets.pop())
  62
  63     def get_sint8(self, fail_value=0):
  64         """Extract a single int8_t from the binary file at the current file position, returns a single integer"""
  65         s = self.read_size(1)
  66         if s:
  67             (v,) = struct.unpack(self.byte_order + "b", s)
  68             return v
  69         else:
  70             return fail_value
  71
  72     def get_uint8(self, fail_value=0):
  73         """Extract a single uint8_t from the binary file at the current file position, returns a single integer"""
  74         s = self.read_size(1)
  75         if s:
  76             (v,) = struct.unpack(self.byte_order + "B", s)
  77             return v
  78         else:
  79             return fail_value
  80
  81     def get_sint16(self, fail_value=0):
  82         """Extract a single int16_t from the binary file at the current file position, returns a single integer"""
  83         s = self.read_size(2)
  84         if s:
  85             (v,) = struct.unpack(self.byte_order + "h", s)
  86             return v
  87         else:
  88             return fail_value
  89
  90     def get_uint16(self, fail_value=0):
  91         """Extract a single uint16_t from the binary file at the current file position, returns a single integer"""
  92         s = self.read_size(2)
  93         if s:
  94             (v,) = struct.unpack(self.byte_order + "H", s)
  95             return v
  96         else:
  97             return fail_value
  98
  99     def get_sint32(self, fail_value=0):
 100         """Extract a single int32_t from the binary file at the current file position, returns a single integer"""
 101         s = self.read_size(4)
 102         if s:
 103             (v,) = struct.unpack(self.byte_order + "i", s)
 104             return v
 105         else:
 106             return fail_value
 107
 108     def get_uint32(self, fail_value=0):
 109         """Extract a single uint32_t from the binary file at the current file position, returns a single integer"""
 110         s = self.read_size(4)
 111         if s:
 112             (v,) = struct.unpack(self.byte_order + "I", s)
 113             return v
 114         else:
 115             return fail_value
 116
 117     def get_sint64(self, fail_value=0):
 118         """Extract a single int64_t from the binary file at the current file position, returns a single integer"""
 119         s = self.read_size(8)
 120         if s:
 121             (v,) = struct.unpack(self.byte_order + "q", s)
 122             return v
 123         else:
 124             return fail_value
 125
 126     def get_uint64(self, fail_value=0):
 127         """Extract a single uint64_t from the binary file at the current file position, returns a single integer"""
 128         s = self.read_size(8)
 129         if s:
 130             (v,) = struct.unpack(self.byte_order + "Q", s)
 131             return v
 132         else:
 133             return fail_value
 134
 135     def get_fixed_length_c_string(
 136         self, n, fail_value="", isprint_only_with_space_padding=False
 137     ):
 138         """Extract a single fixed length C string from the binary file at the current file position, returns a single C string"""
 139         s = self.read_size(n)
 140         if s:
 141             (cstr,) = struct.unpack(self.byte_order + ("%i" % n) + "s", s)
 142             # Strip trialing NULLs
 143             cstr = string.strip(cstr, "\0")
 144             if isprint_only_with_space_padding:
 145                 for c in cstr:
 146                     if c in string.printable or ord(c) == 0:
 147                         continue
 148                     return fail_value
 149             return cstr
 150         else:
 151             return fail_value
 152
 153     def get_c_string(self):
 154         """Extract a single NULL terminated C string from the binary file at the current file position, returns a single C string"""
 155         cstr = ""
 156         byte = self.get_uint8()
 157         while byte != 0:
 158             cstr += "%c" % byte
 159             byte = self.get_uint8()
 160         return cstr
 161
 162     def get_n_sint8(self, n, fail_value=0):
 163         """Extract "n" int8_t integers from the binary file at the current file position, returns a list of integers"""
 164         s = self.read_size(n)
 165         if s:
 166             return struct.unpack(self.byte_order + ("%u" % n) + "b", s)
 167         else:
 168             return (fail_value,) * n
 169
 170     def get_n_uint8(self, n, fail_value=0):
 171         """Extract "n" uint8_t integers from the binary file at the current file position, returns a list of integers"""
 172         s = self.read_size(n)
 173         if s:
 174             return struct.unpack(self.byte_order + ("%u" % n) + "B", s)
 175         else:
 176             return (fail_value,) * n
 177
 178     def get_n_sint16(self, n, fail_value=0):
 179         """Extract "n" int16_t integers from the binary file at the current file position, returns a list of integers"""
 180         s = self.read_size(2 * n)
 181         if s:
 182             return struct.unpack(self.byte_order + ("%u" % n) + "h", s)
 183         else:
 184             return (fail_value,) * n
 185
 186     def get_n_uint16(self, n, fail_value=0):
 187         """Extract "n" uint16_t integers from the binary file at the current file position, returns a list of integers"""
 188         s = self.read_size(2 * n)
 189         if s:
 190             return struct.unpack(self.byte_order + ("%u" % n) + "H", s)
 191         else:
 192             return (fail_value,) * n
 193
 194     def get_n_sint32(self, n, fail_value=0):
 195         """Extract "n" int32_t integers from the binary file at the current file position, returns a list of integers"""
 196         s = self.read_size(4 * n)
 197         if s:
 198             return struct.unpack(self.byte_order + ("%u" % n) + "i", s)
 199         else:
 200             return (fail_value,) * n
 201
 202     def get_n_uint32(self, n, fail_value=0):
 203         """Extract "n" uint32_t integers from the binary file at the current file position, returns a list of integers"""
 204         s = self.read_size(4 * n)
 205         if s:
 206             return struct.unpack(self.byte_order + ("%u" % n) + "I", s)
 207         else:
 208             return (fail_value,) * n
 209
 210     def get_n_sint64(self, n, fail_value=0):
 211         """Extract "n" int64_t integers from the binary file at the current file position, returns a list of integers"""
 212         s = self.read_size(8 * n)
 213         if s:
 214             return struct.unpack(self.byte_order + ("%u" % n) + "q", s)
 215         else:
 216             return (fail_value,) * n
 217
 218     def get_n_uint64(self, n, fail_value=0):
 219         """Extract "n" uint64_t integers from the binary file at the current file position, returns a list of integers"""
 220         s = self.read_size(8 * n)
 221         if s:
 222             return struct.unpack(self.byte_order + ("%u" % n) + "Q", s)
 223         else:
 224             return (fail_value,) * n