/usr/lib/python2.7/dist-packages/elftools/construct/debug.py is in python-pyelftools 0.24-4.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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 | """
Debugging utilities for constructs
"""
from __future__ import print_function
import sys
import traceback
import pdb
import inspect
from .core import Construct, Subconstruct
from .lib import HexString, Container, ListContainer
class Probe(Construct):
"""
A probe: dumps the context, stack frames, and stream content to the screen
to aid the debugging process.
See also Debugger.
Parameters:
* name - the display name
* show_stream - whether or not to show stream contents. default is True.
the stream must be seekable.
* show_context - whether or not to show the context. default is True.
* show_stack - whether or not to show the upper stack frames. default
is True.
* stream_lookahead - the number of bytes to dump when show_stack is set.
default is 100.
Example:
Struct("foo",
UBInt8("a"),
Probe("between a and b"),
UBInt8("b"),
)
"""
__slots__ = [
"printname", "show_stream", "show_context", "show_stack",
"stream_lookahead"
]
counter = 0
def __init__(self, name = None, show_stream = True,
show_context = True, show_stack = True,
stream_lookahead = 100):
Construct.__init__(self, None)
if name is None:
Probe.counter += 1
name = "<unnamed %d>" % (Probe.counter,)
self.printname = name
self.show_stream = show_stream
self.show_context = show_context
self.show_stack = show_stack
self.stream_lookahead = stream_lookahead
def __repr__(self):
return "%s(%r)" % (self.__class__.__name__, self.printname)
def _parse(self, stream, context):
self.printout(stream, context)
def _build(self, obj, stream, context):
self.printout(stream, context)
def _sizeof(self, context):
return 0
def printout(self, stream, context):
obj = Container()
if self.show_stream:
obj.stream_position = stream.tell()
follows = stream.read(self.stream_lookahead)
if not follows:
obj.following_stream_data = "EOF reached"
else:
stream.seek(-len(follows), 1)
obj.following_stream_data = HexString(follows)
print
if self.show_context:
obj.context = context
if self.show_stack:
obj.stack = ListContainer()
frames = [s[0] for s in inspect.stack()][1:-1]
frames.reverse()
for f in frames:
a = Container()
a.__update__(f.f_locals)
obj.stack.append(a)
print("=" * 80)
print("Probe", self.printname)
print(obj)
print("=" * 80)
class Debugger(Subconstruct):
"""
A pdb-based debugger. When an exception occurs in the subcon, a debugger
will appear and allow you to debug the error (and even fix on-the-fly).
Parameters:
* subcon - the subcon to debug
Example:
Debugger(
Enum(UBInt8("foo"),
a = 1,
b = 2,
c = 3
)
)
"""
__slots__ = ["retval"]
def _parse(self, stream, context):
try:
return self.subcon._parse(stream, context)
except Exception:
self.retval = NotImplemented
self.handle_exc("(you can set the value of 'self.retval', "
"which will be returned)")
if self.retval is NotImplemented:
raise
else:
return self.retval
def _build(self, obj, stream, context):
try:
self.subcon._build(obj, stream, context)
except Exception:
self.handle_exc()
def handle_exc(self, msg = None):
print("=" * 80)
print("Debugging exception of %s:" % (self.subcon,))
print("".join(traceback.format_exception(*sys.exc_info())[1:]))
if msg:
print(msg)
pdb.post_mortem(sys.exc_info()[2])
print("=" * 80)
|