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79 lines
2.5 KiB
79 lines
2.5 KiB
#-------------------------------------------------------------------------------
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# elftools: dwarf/abbrevtable.py
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#
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# DWARF abbreviation table
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#
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# Eli Bendersky (eliben@gmail.com)
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# This code is in the public domain
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#-------------------------------------------------------------------------------
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from ..common.utils import struct_parse, dwarf_assert
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class AbbrevTable(object):
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""" Represents a DWARF abbreviation table.
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"""
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def __init__(self, structs, stream, offset):
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""" Create new abbreviation table. Parses the actual table from the
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stream and stores it internally.
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structs:
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A DWARFStructs instance for parsing the data
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stream, offset:
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The stream and offset into the stream where this abbreviation
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table lives.
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"""
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self.structs = structs
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self.stream = stream
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self.offset = offset
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self._abbrev_map = self._parse_abbrev_table()
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def get_abbrev(self, code):
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""" Get the AbbrevDecl for a given code. Raise KeyError if no
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declaration for this code exists.
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"""
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return self._abbrev_map[code]
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def _parse_abbrev_table(self):
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""" Parse the abbrev table from the stream
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"""
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map = {}
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self.stream.seek(self.offset)
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while True:
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decl_code = struct_parse(
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struct=self.structs.Dwarf_uleb128(''),
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stream=self.stream)
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if decl_code == 0:
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break
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declaration = struct_parse(
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struct=self.structs.Dwarf_abbrev_declaration,
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stream=self.stream)
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map[decl_code] = AbbrevDecl(decl_code, declaration)
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return map
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class AbbrevDecl(object):
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""" Wraps a parsed abbreviation declaration, exposing its fields with
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dict-like access, and adding some convenience methods.
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The abbreviation declaration represents an "entry" that points to it.
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"""
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def __init__(self, code, decl):
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self.code = code
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self.decl = decl
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def has_children(self):
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""" Does the entry have children?
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"""
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return self['children_flag'] == 'DW_CHILDREN_yes'
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def iter_attr_specs(self):
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""" Iterate over the attribute specifications for the entry. Yield
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(name, form) pairs.
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"""
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for attr_spec in self['attr_spec']:
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yield attr_spec.name, attr_spec.form
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def __getitem__(self, entry):
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return self.decl[entry]
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