建立 MAG160C 逆向工程交接仓库

2026-08-11 19:08:44 +08:00
commit 8409b27ba3
3135 changed files with 534408 additions and 0 deletions
@@ -0,0 +1,95 @@
+#-------------------------------------------------------------------------------
+# elftools: dwarf/dwarf_utils.py
+#
+# Minor, shared DWARF helpers
+#
+# Eli Bendersky (eliben@gmail.com)
+# This code is in the public domain
+#-------------------------------------------------------------------------------
+from __future__ import annotations
+
+import os
+import binascii
+from typing import IO, TYPE_CHECKING, Any
+
+from ..construct.macros import Array
+from ..common.exceptions import DWARFError
+from ..common.utils import preserve_stream_pos, struct_parse
+
+if TYPE_CHECKING:
+    from collections.abc import Iterator
+
+    from ..construct import Struct
+    from .compileunit import CompileUnit
+    from .structs import DWARFStructs
+    from .typeunit import TypeUnit
+
+
+def _get_base_offset(cu: CompileUnit | TypeUnit, base_attribute_name: str) -> int:
+    """Retrieves a required, base offset-type atribute
+    from the top DIE in the CU. Applies to several indirectly
+    encoded objects - range lists, location lists, strings, addresses.
+    """
+    cu_top_die = cu.get_top_DIE()
+    if base_attribute_name not in cu_top_die.attributes:
+        raise DWARFError("The CU at offset 0x%x needs %s" % (cu.cu_offset, base_attribute_name))
+    return cu_top_die.attributes[base_attribute_name].value
+
+def _resolve_via_offset_table(
+    stream: IO[bytes],
+    cu: CompileUnit | TypeUnit,
+    index: int,
+    base_attribute_name: str,
+) -> int:
+    """Given an index in the offset table and directions where to find it,
+    retrieves an offset. Works for loclists, rnglists.
+
+    The DWARF offset bitness of the CU block in the section matches that
+    of the CU record in dwarf_info. See DWARFv5 standard, section 7.4.
+
+    This is used for translating DW_FORM_loclistx, DW_FORM_rnglistx
+    via the offset table in the respective section.
+    """
+    base_offset = _get_base_offset(cu, base_attribute_name)
+    # That's offset (within the rnglists/loclists/str_offsets section) of
+    # the offset table for this CU's block in that section, which in turn is indexed by the index.
+
+    offset_size = 4 if cu.structs.dwarf_format == 32 else 8
+    with preserve_stream_pos(stream):
+        return base_offset + struct_parse(cu.structs.the_Dwarf_offset, stream, base_offset + index*offset_size)
+
+def _iter_CUs_in_section(
+    stream: IO[bytes],
+    structs: DWARFStructs,
+    parser: Struct,
+) -> Iterator[Any]:
+    """Iterates through the list of CU sections in loclists or rangelists. Almost identical structures there.
+
+    get_parser is a lambda that takes structs, returns the parser
+    """
+    stream.seek(0, os.SEEK_END)
+    endpos = stream.tell()
+    stream.seek(0, os.SEEK_SET)
+
+    offset = 0
+    while offset < endpos:
+        header = struct_parse(parser, stream, offset)
+        if header.offset_count > 0:
+            offset_parser = structs.Dwarf_uint64 if header.is64 else structs.Dwarf_uint32
+            header['offsets'] = struct_parse(Array(header.offset_count, offset_parser('')), stream)
+        else:
+            header['offsets'] = False
+        yield header
+        offset = header.offset_after_length + header.unit_length
+
+def _file_crc32(file: IO[bytes]) -> int:
+    """ Provided a readable binary stream, reads the stream to the end
+        and computes the CRC32 checksum of its contents,
+        with the initial value of 0.
+    """
+    d = file.read(4096)
+    checksum = 0
+    while d:
+        checksum = binascii.crc32(d, checksum)
+        d = file.read(4096)
+    return checksum