path: root/scripts/glibcelf.py

#!/usr/bin/python3
# ELF support functionality for Python.
# Copyright (C) 2022-2025 Free Software Foundation, Inc.
# This file is part of the GNU C Library.
#
# The GNU C Library is free software; you can redistribute it and/or
# modify it under the terms of the GNU Lesser General Public
# License as published by the Free Software Foundation; either
# version 2.1 of the License, or (at your option) any later version.
#
# The GNU C Library 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
# Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public
# License along with the GNU C Library; if not, see
# <https://www.gnu.org/licenses/>.

"""Basic ELF parser.

Use Image.readfile(path) to read an ELF file into memory and begin
parsing it.

"""

import collections
import functools
import os
import struct

import glibcpp

class _MetaNamedValue(type):
    """Used to set up _NamedValue subclasses."""

    @classmethod
    def __prepare__(metacls, cls, bases, **kwds):
        # Indicates an int-based class.  Needed for types like Shn.
        int_based = False
        for base in bases:
            if issubclass(base, int):
                int_based = int
                break
        return dict(by_value={},
                    by_name={},
                    prefix=None,
                    _int_based=int_based)

    def __contains__(self, other):
        return other in self.by_value

class _NamedValue(metaclass=_MetaNamedValue):
    """Typed, named integer constants.

    Constants have the following instance attributes:

    name: The full name of the constant (e.g., "PT_NULL").
    short_name: The name with of the constant without the prefix ("NULL").
    value: The integer value of the constant.

    The following class attributes are available:

    by_value: A dict mapping integers to constants.
    by_name: A dict mapping strings to constants.
    prefix: A string that is removed from the start of short names, or None.

    """

    def __new__(cls, arg0, arg1=None):
        """Instance creation.

        For the one-argument form, the argument must be a string, an
        int, or an instance of this class.  Strings are looked up via
        by_name.  Values are looked up via by_value; if value lookup
        fails, a new unnamed instance is returned.  Instances of this
        class a re returned as-is.

        The two-argument form expects the name (a string) and the
        value (an integer).  A new instance is created in this case.
        The instance is not registered in the by_value/by_name
        dictionaries (but the caller can do that).

        """

        typ0 = type(arg0)
        if arg1 is N