Coverage for /pythoncovmergedfiles/medio/medio/usr/local/lib/python3.8/site-packages/absl/command_name.py: 19%

1# Copyright 2017 The Abseil Authors. 

2# 

3# Licensed under the Apache License, Version 2.0 (the "License"); 

4# you may not use this file except in compliance with the License. 

5# You may obtain a copy of the License at 

6# 

7# http://www.apache.org/licenses/LICENSE-2.0 

8# 

9# Unless required by applicable law or agreed to in writing, software 

10# distributed under the License is distributed on an "AS IS" BASIS, 

11# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 

12# See the License for the specific language governing permissions and 

13# limitations under the License. 

14 

15"""A tiny stand alone library to change the kernel process name on Linux.""" 

16 

17import os 

18import sys 

19 

20# This library must be kept small and stand alone. It is used by small things 

21# that require no extension modules. 

22 

23 

24def make_process_name_useful(): 

25 """Sets the process name to something better than 'python' if possible.""" 

26 set_kernel_process_name(os.path.basename(sys.argv[0])) 

27 

28 

29def set_kernel_process_name(name): 

30 """Changes the Kernel's /proc/self/status process name on Linux. 

31 

32 The kernel name is NOT what will be shown by the ps or top command. 

33 It is a 15 character string stored in the kernel's process table that 

34 is included in the kernel log when a process is OOM killed. 

35 The first 15 bytes of name are used. Non-ASCII unicode is replaced with '?'. 

36 

37 Does nothing if /proc/self/comm cannot be written or prctl() fails. 

38 

39 Args: 

40 name: bytes|unicode, the Linux kernel's command name to set. 

41 """ 

42 if not isinstance(name, bytes): 

43 name = name.encode('ascii', 'replace') 

44 try: 

45 # This is preferred to using ctypes to try and call prctl() when possible. 

46 with open('/proc/self/comm', 'wb') as proc_comm: 

47 proc_comm.write(name[:15]) 

48 except EnvironmentError: 

49 try: 

50 import ctypes # pylint: disable=g-import-not-at-top 

51 except ImportError: 

52 return # No ctypes. 

53 try: 

54 libc = ctypes.CDLL('libc.so.6') 

55 except EnvironmentError: 

56 return # No libc.so.6. 

57 pr_set_name = ctypes.c_ulong(15) # linux/prctl.h PR_SET_NAME value. 

58 zero = ctypes.c_ulong(0) 

59 try: 

60 libc.prctl(pr_set_name, name, zero, zero, zero) 

61 # Ignore the prctl return value. Nothing we can do if it errored. 

62 except AttributeError: 

63 return # No prctl.