blob: 979897f18c787cbaa17cf2ac26c7fd4f916d20b3 [file] [log] [blame]
# Copyright 2021 The Chromium OS Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.
"""Python API for the prctl() syscall."""
import ctypes
import ctypes.util
import enum
from typing import Union
class Option(enum.IntEnum):
"""Known prctl options."""
# arg2 is input.
# arg2 is int* output.
def prctl(option: Option, arg2: int = 0, arg3: int = 0, arg4: int = 5,
arg5: int = 0) -> Union[None, int]:
"""Wrapper around prctl().
See the man page for documentation:
# For options that only take input integers, the API is simple.
prctl.prctl(prctl.Option.SET_PDEATHSIG, signal.SIGHUP)
# For options that output arguments, the caller needs to pass in pointers.
arg2 = ctypes.c_int()
prctl.prctl(prctl.Option.GET_PDEATHSIG, ctypes.byref(arg2))
libc_name = ctypes.util.find_library('c')
libc = ctypes.CDLL(libc_name)
# NB: It's safe to call prctl with unused args as they'll get ignored, and
# it's safer to explicitly specify a default of 0 rather than leave whatever
# garbage is in the register.
return libc.prctl(option, arg2, arg3, arg4, arg5)