Christoph Brandau
53ebc5d055
The changes align the project with the 2025.0.0 lsprotocol release, removing the old backport and updating type hints in the protocol hooks to use Sequence where appropriate. The dist-info and packaging metadata for older lsprotocol versions are replaced with the new 2025.0.0 artifacts. - Remove exceptiongroup backport used on Python <3.11 - Use Sequence instead of List in LS protocol hooks - Replace old dist-info with 2025.0.0 metadata
109 lines
3.2 KiB
Python
109 lines
3.2 KiB
Python
"""
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ELF file parser.
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This provides a class ``ELFFile`` that parses an ELF executable in a similar
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interface to ``ZipFile``. Only the read interface is implemented.
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ELF header: https://refspecs.linuxfoundation.org/elf/gabi4+/ch4.eheader.html
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"""
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from __future__ import annotations
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import enum
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import os
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import struct
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from typing import IO
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class ELFInvalid(ValueError):
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pass
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class EIClass(enum.IntEnum):
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C32 = 1
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C64 = 2
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class EIData(enum.IntEnum):
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Lsb = 1
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Msb = 2
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class EMachine(enum.IntEnum):
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I386 = 3
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S390 = 22
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Arm = 40
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X8664 = 62
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AArch64 = 183
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class ELFFile:
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"""
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Representation of an ELF executable.
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"""
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def __init__(self, f: IO[bytes]) -> None:
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self._f = f
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try:
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ident = self._read("16B")
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except struct.error as e:
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raise ELFInvalid("unable to parse identification") from e
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magic = bytes(ident[:4])
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if magic != b"\x7fELF":
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raise ELFInvalid(f"invalid magic: {magic!r}")
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self.capacity = ident[4] # Format for program header (bitness).
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self.encoding = ident[5] # Data structure encoding (endianness).
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try:
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# e_fmt: Format for the ELF header.
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# p_fmt: Format for a program header.
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# p_idx: Indexes to find p_type, p_offset, and p_filesz.
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e_fmt, self._p_fmt, self._p_idx = {
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(1, 1): ("<HHIIIIIHHH", "<IIIIIIII", (0, 1, 4)), # 32-bit LSB.
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(1, 2): (">HHIIIIIHHH", ">IIIIIIII", (0, 1, 4)), # 32-bit MSB.
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(2, 1): ("<HHIQQQIHHH", "<IIQQQQQQ", (0, 2, 5)), # 64-bit LSB.
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(2, 2): (">HHIQQQIHHH", ">IIQQQQQQ", (0, 2, 5)), # 64-bit MSB.
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}[(self.capacity, self.encoding)]
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except KeyError as e:
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raise ELFInvalid(
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f"unrecognized capacity ({self.capacity}) or encoding ({self.encoding})"
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) from e
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try:
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(
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_,
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self.machine, # Architecture type.
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_,
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_,
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self._e_phoff, # Offset of program header.
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_,
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self.flags, # Processor-specific flags.
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_,
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self._e_phentsize, # Size of a program header entry.
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self._e_phnum, # Number of program headers.
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) = self._read(e_fmt)
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except struct.error as e:
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raise ELFInvalid("unable to parse machine and section information") from e
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def _read(self, fmt: str) -> tuple[int, ...]:
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return struct.unpack(fmt, self._f.read(struct.calcsize(fmt)))
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@property
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def interpreter(self) -> str | None:
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"""
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The path recorded in the ``PT_INTERP`` section header.
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"""
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for index in range(self._e_phnum):
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self._f.seek(self._e_phoff + self._e_phentsize * index)
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try:
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data = self._read(self._p_fmt)
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except struct.error:
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continue
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if data[self._p_idx[0]] != 3: # Not PT_INTERP.
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continue
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self._f.seek(data[self._p_idx[1]])
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return os.fsdecode(self._f.read(data[self._p_idx[2]])).strip("\0")
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return None
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