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pysim
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Code Issues Releases Wiki Activity

filesystem: Introduce 'construct' support 

This allows for pure declarative encoders/decoders for linear fixed
and transparent EFs.

Change-Id: Id0765ec3ddb8c044838ce47d0ff8740720a32b15
This commit is contained in:
Harald Welte 2021-04-10 19:05:37 +02:00
parent 703f933b40
commit 2db5cfb525
2 changed files with 36 additions and 2 deletions
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9
pySim/construct.py
View File

@ -1,5 +1,5 @@
from construct import *
from pySim.utils import b2h, h2b
from pySim.utils import b2h, h2b, swap_nibbles
"""Utility code related to the integration of the 'construct' declarative parser."""
@ -26,6 +26,13 @@ class HexAdapter(Adapter):
def _encode(self, obj, context, path):
return h2b(obj)
class BcdAdapter(Adapter):
"""convert a bytes() type to a string of BCD nibbles."""
def _decode(self, obj, context, path):
return swap_nibbles(b2h(obj))
def _encode(self, obj, context, path):
return h2b(swap_nibbles(obj))
def filter_dict(d, exclude_prefix='_'):
"""filter the input dict to ensure no keys starting with 'exclude_prefix' remain."""
res = {}

29
pySim/filesystem.py
View File

@ -35,6 +35,7 @@ import argparse
from typing import cast, Optional, Iterable, List, Any, Dict, Tuple
from pySim.utils import sw_match, h2b, b2h, is_hex
from pySim.construct import filter_dict
from pySim.exceptions import *
from pySim.jsonpath import js_path_find, js_path_modify
@ -466,6 +467,7 @@ class TransparentEF(CardEF):
size : tuple of (minimum_size, recommended_size)
"""
super().__init__(fid=fid, sfid=sfid, name=name, desc=desc, parent=parent)
self._construct = None
self.size = size
self.shell_commands = [self.ShellCommands()]
@ -487,6 +489,8 @@ class TransparentEF(CardEF):
method = getattr(self, '_decode_hex', None)
if callable(method):
return method(b2h(raw_bin_data))
if self._construct:
return filter_dict(self._construct.parse(raw_bin_data, total_len=len(raw_bin_data)))
return {'raw': raw_bin_data.hex()}
def decode_hex(self, raw_hex_data:str) -> dict:
@ -508,6 +512,8 @@ class TransparentEF(CardEF):
method = getattr(self, '_decode_bin', None)
if callable(method):
return method(raw_bin_data)
if self._construct:
return filter_dict(self._construct.parse(raw_bin_data, total_len=len(raw_bin_data)))
return {'raw': raw_bin_data.hex()}
def encode_bin(self, abstract_data:dict) -> bytearray:
@ -528,6 +534,8 @@ class TransparentEF(CardEF):
method = getattr(self, '_encode_hex', None)
if callable(method):
return h2b(method(abstract_data))
if self._construct:
return self._construct.build(abstract_data)
raise NotImplementedError
def encode_hex(self, abstract_data:dict) -> str:
@ -549,6 +557,8 @@ class TransparentEF(CardEF):
if callable(method):
raw_bin_data = method(abstract_data)
return b2h(raw_bin_data)
if self._construct:
return b2h(self._construct.build(abstract_data))
raise NotImplementedError
@ -683,6 +693,7 @@ class LinFixedEF(CardEF):
super().__init__(fid=fid, sfid=sfid, name=name, desc=desc, parent=parent)
self.rec_len = rec_len
self.shell_commands = [self.ShellCommands()]
self._construct = None
def decode_record_hex(self, raw_hex_data:str) -> dict:
"""Decode raw (hex string) data into abstract representation.
@ -703,6 +714,8 @@ class LinFixedEF(CardEF):
method = getattr(self, '_decode_record_bin', None)
if callable(method):
return method(raw_bin_data)
if self._construct:
return filter_dict(self._construct.parse(raw_bin_data, total_len=len(raw_bin_data)))
return {'raw': raw_bin_data.hex()}
def decode_record_bin(self, raw_bin_data:bytearray) -> dict:
@ -724,6 +737,8 @@ class LinFixedEF(CardEF):
method = getattr(self, '_decode_record_hex', None)
if callable(method):
return method(raw_hex_data)
if self._construct:
return filter_dict(self._construct.parse(raw_bin_data, total_len=len(raw_bin_data)))
return {'raw': raw_hex_data}
def encode_record_hex(self, abstract_data:dict) -> str:
@ -745,6 +760,8 @@ class LinFixedEF(CardEF):
if callable(method):
raw_bin_data = method(abstract_data)
return b2h(raw_bin_data)
if self._construct:
return b2h(self._construct.build(abstract_data))
raise NotImplementedError
def encode_record_bin(self, abstract_data:dict) -> bytearray:
@ -765,6 +782,8 @@ class LinFixedEF(CardEF):
method = getattr(self, '_encode_record_hex', None)
if callable(method):
return h2b(method(abstract_data))
if self._construct:
return self._construct.build(abstract_data)
raise NotImplementedError
class CyclicEF(LinFixedEF):
@ -813,10 +832,12 @@ class TransRecEF(TransparentEF):
method = getattr(self, '_decode_record_hex', None)
if callable(method):
return method(raw_hex_data)
raw_bin_data = h2b(raw_hex_data)
method = getattr(self, '_decode_record_bin', None)
if callable(method):
raw_bin_data = h2b(raw_hex_data)
return method(raw_bin_data)
if self._construct:
return filter_dict(self._construct.parse(raw_bin_data, total_len=len(raw_bin_data)))
return {'raw': raw_hex_data}
def decode_record_bin(self, raw_bin_data:bytearray) -> dict:
@ -838,6 +859,8 @@ class TransRecEF(TransparentEF):
method = getattr(self, '_decode_record_hex', None)
if callable(method):
return method(raw_hex_data)
if self._construct:
return filter_dict(self._construct.parse(raw_bin_data, total_len=len(raw_bin_data)))
return {'raw': raw_hex_data}
def encode_record_hex(self, abstract_data:dict) -> str:
@ -858,6 +881,8 @@ class TransRecEF(TransparentEF):
method = getattr(self, '_encode_record_bin', None)
if callable(method):
return b2h(method(abstract_data))
if self._construct:
return b2h(filter_dict(self._construct.build(abstract_data)))
raise NotImplementedError
def encode_record_bin(self, abstract_data:dict) -> bytearray:
@ -878,6 +903,8 @@ class TransRecEF(TransparentEF):
method = getattr(self, '_encode_record_hex', None)
if callable(method):
return h2b(method(abstract_data))
if self._construct:
return filter_dict(self._construct.build(abstract_data))
raise NotImplementedError
def _decode_bin(self, raw_bin_data:bytearray):