# Copyright 2017 The Abseil Authors.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""A tiny stand alone library to change the kernel process name on Linux."""
import os
import sys
# This library must be kept small and stand alone. It is used by small things
# that require no extension modules.
[docs]def make_process_name_useful():
"""Sets the process name to something better than 'python' if possible."""
set_kernel_process_name(os.path.basename(sys.argv[0]))
[docs]def set_kernel_process_name(name):
"""Changes the Kernel's /proc/self/status process name on Linux.
The kernel name is NOT what will be shown by the ps or top command.
It is a 15 character string stored in the kernel's process table that
is included in the kernel log when a process is OOM killed.
The first 15 bytes of name are used. Non-ASCII unicode is replaced with '?'.
Does nothing if /proc/self/comm cannot be written or prctl() fails.
Args:
name: bytes|unicode, the Linux kernel's command name to set.
"""
if not isinstance(name, bytes):
name = name.encode('ascii', 'replace')
try:
# This is preferred to using ctypes to try and call prctl() when possible.
with open('/proc/self/comm', 'wb') as proc_comm:
proc_comm.write(name[:15])
except EnvironmentError:
try:
import ctypes # pylint: disable=g-import-not-at-top
except ImportError:
return # No ctypes.
try:
libc = ctypes.CDLL('libc.so.6')
except EnvironmentError:
return # No libc.so.6.
pr_set_name = ctypes.c_ulong(15) # linux/prctl.h PR_SET_NAME value.
zero = ctypes.c_ulong(0)
try:
libc.prctl(pr_set_name, name, zero, zero, zero)
# Ignore the prctl return value. Nothing we can do if it errored.
except AttributeError:
return # No prctl.