venv/lib/python3.11/site-packages/pip/_internal/utils/glibc.py

   1 import os
   2 import sys
   3 from typing import Optional, Tuple
   4
   5
   6 def glibc_version_string() -> Optional[str]:
   7     "Returns glibc version string, or None if not using glibc."
   8     return glibc_version_string_confstr() or glibc_version_string_ctypes()
   9
  10
  11 def glibc_version_string_confstr() -> Optional[str]:
  12     "Primary implementation of glibc_version_string using os.confstr."
  13     # os.confstr is quite a bit faster than ctypes.DLL. It's also less likely
  14     # to be broken or missing. This strategy is used in the standard library
  15     # platform module:
  16     # https://github.com/python/cpython/blob/fcf1d003bf4f0100c9d0921ff3d70e1127ca1b71/Lib/platform.py#L175-L183
  17     if sys.platform == "win32":
  18         return None
  19     try:
  20         gnu_libc_version = os.confstr("CS_GNU_LIBC_VERSION")
  21         if gnu_libc_version is None:
  22             return None
  23         # os.confstr("CS_GNU_LIBC_VERSION") returns a string like "glibc 2.17":
  24         _, version = gnu_libc_version.split()
  25     except (AttributeError, OSError, ValueError):
  26         # os.confstr() or CS_GNU_LIBC_VERSION not available (or a bad value)...
  27         return None
  28     return version
  29
  30
  31 def glibc_version_string_ctypes() -> Optional[str]:
  32     "Fallback implementation of glibc_version_string using ctypes."
  33
  34     try:
  35         import ctypes
  36     except ImportError:
  37         return None
  38
  39     # ctypes.CDLL(None) internally calls dlopen(NULL), and as the dlopen
  40     # manpage says, "If filename is NULL, then the returned handle is for the
  41     # main program". This way we can let the linker do the work to figure out
  42     # which libc our process is actually using.
  43     process_namespace = ctypes.CDLL(None)
  44     try:
  45         gnu_get_libc_version = process_namespace.gnu_get_libc_version
  46     except AttributeError:
  47         # Symbol doesn't exist -> therefore, we are not linked to
  48         # glibc.
  49         return None
  50
  51     # Call gnu_get_libc_version, which returns a string like "2.5"
  52     gnu_get_libc_version.restype = ctypes.c_char_p
  53     version_str = gnu_get_libc_version()
  54     # py2 / py3 compatibility:
  55     if not isinstance(version_str, str):
  56         version_str = version_str.decode("ascii")
  57
  58     return version_str
  59
  60
  61 # platform.libc_ver regularly returns completely nonsensical glibc
  62 # versions. E.g. on my computer, platform says:
  63 #
  64 #   ~$ python2.7 -c 'import platform; print(platform.libc_ver())'
  65 #   ('glibc', '2.7')
  66 #   ~$ python3.5 -c 'import platform; print(platform.libc_ver())'
  67 #   ('glibc', '2.9')
  68 #
  69 # But the truth is:
  70 #
  71 #   ~$ ldd --version
  72 #   ldd (Debian GLIBC 2.22-11) 2.22
  73 #
  74 # This is unfortunate, because it means that the linehaul data on libc
  75 # versions that was generated by pip 8.1.2 and earlier is useless and
  76 # misleading. Solution: instead of using platform, use our code that actually
  77 # works.
  78 def libc_ver() -> Tuple[str, str]:
  79     """Try to determine the glibc version
  80
  81     Returns a tuple of strings (lib, version) which default to empty strings
  82     in case the lookup fails.
  83     """
  84     glibc_version = glibc_version_string()
  85     if glibc_version is None:
  86         return ("", "")
  87     else:
  88         return ("glibc", glibc_version)