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#
# Copyright (C) 2011 EADS France, Fabrice Desclaux <fabrice.desclaux@eads.net>
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License along
# with this program; if not, write to the Free Software Foundation, Inc.,
# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
#
import math
from miasm2.core.utils import BoundedDict
class bin_stream(object):
# Cache must be initialized by entering atomic mode
_cache = None
CACHE_SIZE = 10000
# By default, no atomic mode
_atomic_mode = False
def __init__(self, *args, **kargs):
pass
def __repr__(self):
return "<%s !!>" % self.__class__.__name__
def hexdump(self, offset, l):
return
def enter_atomic_mode(self):
"""Enter atomic mode. In this mode, read may be cached"""
self._atomic_mode = True
self._cache = BoundedDict(self.CACHE_SIZE)
def leave_atomic_mode(self):
"""Leave atomic mode"""
self._atomic_mode = False
self._cache = None
def _getbytes(self, start, length):
return self.bin[start:start + l]
def getbytes(self, start, l=1):
"""Return the bytes from the bit stream
@start: starting offset (in byte)
@l: (optional) number of bytes to read
Wrapper on _getbytes, with atomic mode handling.
"""
if self._atomic_mode:
val = self._cache.get((start,l), None)
if val is None:
val = self._getbytes(start, l)
self._cache[(start,l)] = val
else:
val = self._getbytes(start, l)
return val
def getbits(self, start, n):
"""Return the bits from the bit stream
@start: the offset in bits
@n: number of bits to read
"""
# Trivial case
if n == 0:
return 0
# Get initial bytes
if n > self.getlen() * 8:
raise IOError('not enough bits %r %r' % (n, len(self.bin) * 8))
temp = self.getbytes(start / 8, int(math.ceil(n / 8.)))
if not temp:
raise IOError('cannot get bytes')
# Init
start = start % 8
out = 0
while n:
# Get needed bits, working on maximum 8 bits at a time
cur_byte_idx = start / 8
new_bits = ord(temp[cur_byte_idx])
to_keep = 8 - start % 8
new_bits &= (1 << to_keep) - 1
cur_len = min(to_keep, n)
new_bits >>= (to_keep - cur_len)
# Update output
out <<= cur_len
out |= new_bits
# Update counters
n -= cur_len
start += cur_len
return out
class bin_stream_str(bin_stream):
def __init__(self, input_str="", offset=0L, shift=0):
bin_stream.__init__(self)
self.bin = input_str
self.offset = offset
self.shift = shift
self.l = len(input_str)
def getbytes(self, start, l=1):
if start + l + self.shift > self.l:
raise IOError("not enough bytes in str")
return super(bin_stream_str, self).getbytes(start + self.shift, l)
def readbs(self, l=1):
if self.offset + l + self.shift > self.l:
raise IOError("not enough bytes in str")
self.offset += l
return self.bin[self.offset - l + self.shift:self.offset + self.shift]
def __str__(self):
out = self.bin[self.offset + self.shift:]
return out
def setoffset(self, val):
self.offset = val
def getlen(self):
return self.l - (self.offset + self.shift)
class bin_stream_file(bin_stream):
def __init__(self, binary, offset=0L, shift=0):
bin_stream.__init__(self)
self.bin = binary
self.bin.seek(0, 2)
self.shift = shift
self.l = self.bin.tell()
self.offset = offset
def getoffset(self):
return self.bin.tell() - self.shift
def setoffset(self, val):
self.bin.seek(val + self.shift)
offset = property(getoffset, setoffset)
def readbs(self, l=1):
if self.offset + l + self.shift > self.l:
raise IOError("not enough bytes in file")
return self.bin.read(l)
def __str__(self):
return str(self.bin)
def getlen(self):
return self.l - (self.offset + self.shift)
class bin_stream_container(bin_stream):
def __init__(self, virt_view, offset=0L):
bin_stream.__init__(self)
self.bin = virt_view
self.l = virt_view.max_addr()
self.offset = offset
def is_addr_in(self, ad):
return self.bin.is_addr_in(ad)
def getlen(self):
return self.l
def readbs(self, l=1):
if self.offset + l > self.l:
raise IOError("not enough bytes")
self.offset += l
return self.bin.get(self.offset - l, self.offset)
def getbytes(self, start, l=1):
return self.bin.get(start, start + l)
def __str__(self):
out = self.bin.get(self.offset, self.offset + self.l)
return out
def setoffset(self, val):
self.offset = val
class bin_stream_pe(bin_stream_container):
pass
class bin_stream_elf(bin_stream_container):
pass
class bin_stream_vm(bin_stream):
def __init__(self, vm, offset=0L, base_offset=0L):
self.offset = offset
self.base_offset = base_offset
self.vm = vm
def getlen(self):
return 0xFFFFFFFFFFFFFFFF
def getbytes(self, start, l=1):
try:
s = self.vm.get_mem(start + self.base_offset, l)
except:
raise IOError('cannot get mem ad', hex(start))
return s
def readbs(self, l=1):
try:
s = self.vm.get_mem(self.offset + self.base_offset, l)
except:
raise IOError('cannot get mem ad', hex(self.offset))
self.offset += l
return s
def setoffset(self, val):
self.offset = val
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