prompt: We are currently solving the following issue within our repository. Here is the issue text:
  --- BEGIN ISSUE ---
  pip._internal.utils.glibc_version_string() can use os.confstr('CS_GNU_LIBC_VERSION') to avoid ctypes
  Currently, the pip._internal.utils.glibc_version_string() function is implemented with ctypes to access gnu_get_libc_version() function. But os.confstr('CS_GNU_LIBC_VERSION') could be used instead to avoid ctypes.
  
  I recently modified platform.libc_ver() on Python stdlib to use os.confstr('CS_GNU_LIBC_VERSION') is available:
  * https://bugs.python.org/issue35389
  * https://github.com/python/cpython/blob/d4efd917ac24940063a1ce80073fe3570c5f07f8/Lib/platform.py#L174-L183
  
  ```py
      if executable is None:
          try:
              ver = os.confstr('CS_GNU_LIBC_VERSION')
              # parse 'glibc 2.28' as ('glibc', '2.28')
              parts = ver.split(maxsplit=1)
              if len(parts) == 2:
                  return tuple(parts)
          except (AttributeError, ValueError, OSError):
              # os.confstr() or CS_GNU_LIBC_VERSION value not available
              pass
  ```
  
  Note: I noticed this issue when an user reported a traceback in pip when the ctypes is not available: https://mail.python.org/archives/list/python-dev@python.org/thread/MTIRNYFAZTQQPHKAQXXREP33NYV2TW2J/
  Handle ImportError and OSError when importing ctypes (#6543)
  Non-dynamic executables can raise OSError when importing ctypes
  because dlopen(NULL) is called on module import and dlopen()
  won't work on non-dynamic executables.
  
  This commit teaches the glibc version sniffing module to
  handle a missing or not working ctypes module.
  
  With this change applied, `pip install` works on non-dynamic / fully statically linked Python executables on Linux.
  
  
  --- END ISSUE ---
  
  Below are some code segments, each from a relevant file. One or more of these files may contain bugs.
  --- BEGIN FILES ---
  Path: `src/pip/_internal/utils/glibc.py`
  Content:
  ```
  1 from __future__ import absolute_import
  2 
  3 import ctypes
  4 import re
  5 import warnings
  6 
  7 from pip._internal.utils.typing import MYPY_CHECK_RUNNING
  8 
  9 if MYPY_CHECK_RUNNING:
  10     from typing import Optional, Tuple
  11 
  12 
  13 def glibc_version_string():
  14     # type: () -> Optional[str]
  15     "Returns glibc version string, or None if not using glibc."
  16 
  17     # ctypes.CDLL(None) internally calls dlopen(NULL), and as the dlopen
  18     # manpage says, "If filename is NULL, then the returned handle is for the
  19     # main program". This way we can let the linker do the work to figure out
  20     # which libc our process is actually using.
  21     process_namespace = ctypes.CDLL(None)
  22     try:
  23         gnu_get_libc_version = process_namespace.gnu_get_libc_version
  24     except AttributeError:
  25         # Symbol doesn't exist -> therefore, we are not linked to
  26         # glibc.
  27         return None
  28 
  29     # Call gnu_get_libc_version, which returns a string like "2.5"
  30     gnu_get_libc_version.restype = ctypes.c_char_p
  31     version_str = gnu_get_libc_version()
  32     # py2 / py3 compatibility:
  33     if not isinstance(version_str, str):
  34         version_str = version_str.decode("ascii")
  35 
  36     return version_str
  37 
  38 
  39 # Separated out from have_compatible_glibc for easier unit testing
  40 def check_glibc_version(version_str, required_major, minimum_minor):
  41     # type: (str, int, int) -> bool
  42     # Parse string and check against requested version.
  43     #
  44     # We use a regexp instead of str.split because we want to discard any
  45     # random junk that might come after the minor version -- this might happen
  46     # in patched/forked versions of glibc (e.g. Linaro's version of glibc
  47     # uses version strings like "2.20-2014.11"). See gh-3588.
  48     m = re.match(r"(?P<major>[0-9]+)\.(?P<minor>[0-9]+)", version_str)
  49     if not m:
  50         warnings.warn("Expected glibc version with 2 components major.minor,"
  51                       " got: %s" % version_str, RuntimeWarning)
  52         return False
  53     return (int(m.group("major")) == required_major and
  54             int(m.group("minor")) >= minimum_minor)
  55 
  56 
  57 def have_compatible_glibc(required_major, minimum_minor):
  58     # type: (int, int) -> bool
  59     version_str = glibc_version_string()  # type: Optional[str]
  60     if version_str is None:
  61         return False
  62     return check_glibc_version(version_str, required_major, minimum_minor)
  63 
  64 
  65 # platform.libc_ver regularly returns completely nonsensical glibc
  66 # versions. E.g. on my computer, platform says:
  67 #
  68 #   ~$ python2.7 -c 'import platform; print(platform.libc_ver())'
  69 #   ('glibc', '2.7')
  70 #   ~$ python3.5 -c 'import platform; print(platform.libc_ver())'
  71 #   ('glibc', '2.9')
  72 #
  73 # But the truth is:
  74 #
  75 #   ~$ ldd --version
  76 #   ldd (Debian GLIBC 2.22-11) 2.22
  77 #
  78 # This is unfortunate, because it means that the linehaul data on libc
  79 # versions that was generated by pip 8.1.2 and earlier is useless and
  80 # misleading. Solution: instead of using platform, use our code that actually
  81 # works.
  82 def libc_ver():
  83     # type: () -> Tuple[str, str]
  84     """Try to determine the glibc version
  85 
  86     Returns a tuple of strings (lib, version) which default to empty strings
  87     in case the lookup fails.
  88     """
  89     glibc_version = glibc_version_string()
  90     if glibc_version is None:
  91         return ("", "")
  92     else:
  93         return ("glibc", glibc_version)
  94
  ```
  --- END FILES ---
  
  Please first localize the bug based on the issue statement, and then generate a patch according to the `git diff` format fenced by three backticks.
  
  Here is an example:
  
  ```diff
  diff --git a/examples/server_async.py b/examples/server_async.py
  --- a/examples/server_async.py
  +++ b/examples/server_async.py
  @@ -313,4 +313,4 @@
   
   
   if __name__ == "__main__":
  -    asyncio.run(run_async_server("."), debug=True)
  +    asyncio.run(run_async_server(), debug=True)
  diff --git a/examples/server_sync.py b/examples/server_sync.py
  --- a/examples/server_sync.py
  +++ b/examples/server_sync.py
  @@ -313,5 +313,5 @@
   
   
   if __name__ == "__main__":
  -    server = run_sync_server(".")
  +    server = run_sync_server()
       server.shutdown()
  
  ```
  
golden_diff: diff --git a/src/pip/_internal/utils/glibc.py b/src/pip/_internal/utils/glibc.py
  --- a/src/pip/_internal/utils/glibc.py
  +++ b/src/pip/_internal/utils/glibc.py
  @@ -1,6 +1,6 @@
   from __future__ import absolute_import
   
  -import ctypes
  +import os
   import re
   import warnings
   
  @@ -13,6 +13,33 @@
   def glibc_version_string():
       # type: () -> Optional[str]
       "Returns glibc version string, or None if not using glibc."
  +    return glibc_version_string_confstr() or glibc_version_string_ctypes()
  +
  +
  +def glibc_version_string_confstr():
  +    # type: () -> Optional[str]
  +    "Primary implementation of glibc_version_string using os.confstr."
  +    # os.confstr is quite a bit faster than ctypes.DLL. It's also less likely
  +    # to be broken or missing. This strategy is used in the standard library
  +    # platform module:
  +    # https://github.com/python/cpython/blob/fcf1d003bf4f0100c9d0921ff3d70e1127ca1b71/Lib/platform.py#L175-L183
  +    try:
  +        # os.confstr("CS_GNU_LIBC_VERSION") returns a string like "glibc 2.17":
  +        _, version = os.confstr("CS_GNU_LIBC_VERSION").split()
  +    except (AttributeError, OSError, ValueError):
  +        # os.confstr() or CS_GNU_LIBC_VERSION not available (or a bad value)...
  +        return None
  +    return version
  +
  +
  +def glibc_version_string_ctypes():
  +    # type: () -> Optional[str]
  +    "Fallback implementation of glibc_version_string using ctypes."
  +
  +    try:
  +        import ctypes
  +    except ImportError:
  +        return None
   
       # ctypes.CDLL(None) internally calls dlopen(NULL), and as the dlopen
       # manpage says, "If filename is NULL, then the returned handle is for the
  @@ -56,7 +83,7 @@
   
   def have_compatible_glibc(required_major, minimum_minor):
       # type: (int, int) -> bool
  -    version_str = glibc_version_string()  # type: Optional[str]
  +    version_str = glibc_version_string()
       if version_str is None:
           return False
       return check_glibc_version(version_str, required_major, minimum_minor)
  
verification_info: {"golden_diff": "diff --git a/src/pip/_internal/utils/glibc.py b/src/pip/_internal/utils/glibc.py\n--- a/src/pip/_internal/utils/glibc.py\n+++ b/src/pip/_internal/utils/glibc.py\n@@ -1,6 +1,6 @@\n from __future__ import absolute_import\n \n-import ctypes\n+import os\n import re\n import warnings\n \n@@ -13,6 +13,33 @@\n def glibc_version_string():\n     # type: () -> Optional[str]\n     \"Returns glibc version string, or None if not using glibc.\"\n+    return glibc_version_string_confstr() or glibc_version_string_ctypes()\n+\n+\n+def glibc_version_string_confstr():\n+    # type: () -> Optional[str]\n+    \"Primary implementation of glibc_version_string using os.confstr.\"\n+    # os.confstr is quite a bit faster than ctypes.DLL. It's also less likely\n+    # to be broken or missing. This strategy is used in the standard library\n+    # platform module:\n+    # https://github.com/python/cpython/blob/fcf1d003bf4f0100c9d0921ff3d70e1127ca1b71/Lib/platform.py#L175-L183\n+    try:\n+        # os.confstr(\"CS_GNU_LIBC_VERSION\") returns a string like \"glibc 2.17\":\n+        _, version = os.confstr(\"CS_GNU_LIBC_VERSION\").split()\n+    except (AttributeError, OSError, ValueError):\n+        # os.confstr() or CS_GNU_LIBC_VERSION not available (or a bad value)...\n+        return None\n+    return version\n+\n+\n+def glibc_version_string_ctypes():\n+    # type: () -> Optional[str]\n+    \"Fallback implementation of glibc_version_string using ctypes.\"\n+\n+    try:\n+        import ctypes\n+    except ImportError:\n+        return None\n \n     # ctypes.CDLL(None) internally calls dlopen(NULL), and as the dlopen\n     # manpage says, \"If filename is NULL, then the returned handle is for the\n@@ -56,7 +83,7 @@\n \n def have_compatible_glibc(required_major, minimum_minor):\n     # type: (int, int) -> bool\n-    version_str = glibc_version_string()  # type: Optional[str]\n+    version_str = glibc_version_string()\n     if version_str is None:\n         return False\n     return check_glibc_version(version_str, required_major, minimum_minor)\n", "issue": "pip._internal.utils.glibc_version_string() can use os.confstr('CS_GNU_LIBC_VERSION') to avoid ctypes\nCurrently, the pip._internal.utils.glibc_version_string() function is implemented with ctypes to access gnu_get_libc_version() function. But os.confstr('CS_GNU_LIBC_VERSION') could be used instead to avoid ctypes.\r\n\r\nI recently modified platform.libc_ver() on Python stdlib to use os.confstr('CS_GNU_LIBC_VERSION') is available:\r\n* https://bugs.python.org/issue35389\r\n* https://github.com/python/cpython/blob/d4efd917ac24940063a1ce80073fe3570c5f07f8/Lib/platform.py#L174-L183\r\n\r\n```py\r\n    if executable is None:\r\n        try:\r\n            ver = os.confstr('CS_GNU_LIBC_VERSION')\r\n            # parse 'glibc 2.28' as ('glibc', '2.28')\r\n            parts = ver.split(maxsplit=1)\r\n            if len(parts) == 2:\r\n                return tuple(parts)\r\n        except (AttributeError, ValueError, OSError):\r\n            # os.confstr() or CS_GNU_LIBC_VERSION value not available\r\n            pass\r\n```\r\n\r\nNote: I noticed this issue when an user reported a traceback in pip when the ctypes is not available: https://mail.python.org/archives/list/python-dev@python.org/thread/MTIRNYFAZTQQPHKAQXXREP33NYV2TW2J/\nHandle ImportError and OSError when importing ctypes (#6543)\nNon-dynamic executables can raise OSError when importing ctypes\r\nbecause dlopen(NULL) is called on module import and dlopen()\r\nwon't work on non-dynamic executables.\r\n\r\nThis commit teaches the glibc version sniffing module to\r\nhandle a missing or not working ctypes module.\r\n\r\nWith this change applied, `pip install` works on non-dynamic / fully statically linked Python executables on Linux.\r\n\n", "before_files": [{"content": "from __future__ import absolute_import\n\nimport ctypes\nimport re\nimport warnings\n\nfrom pip._internal.utils.typing import MYPY_CHECK_RUNNING\n\nif MYPY_CHECK_RUNNING:\n    from typing import Optional, Tuple\n\n\ndef glibc_version_string():\n    # type: () -> Optional[str]\n    \"Returns glibc version string, or None if not using glibc.\"\n\n    # ctypes.CDLL(None) internally calls dlopen(NULL), and as the dlopen\n    # manpage says, \"If filename is NULL, then the returned handle is for the\n    # main program\". This way we can let the linker do the work to figure out\n    # which libc our process is actually using.\n    process_namespace = ctypes.CDLL(None)\n    try:\n        gnu_get_libc_version = process_namespace.gnu_get_libc_version\n    except AttributeError:\n        # Symbol doesn't exist -> therefore, we are not linked to\n        # glibc.\n        return None\n\n    # Call gnu_get_libc_version, which returns a string like \"2.5\"\n    gnu_get_libc_version.restype = ctypes.c_char_p\n    version_str = gnu_get_libc_version()\n    # py2 / py3 compatibility:\n    if not isinstance(version_str, str):\n        version_str = version_str.decode(\"ascii\")\n\n    return version_str\n\n\n# Separated out from have_compatible_glibc for easier unit testing\ndef check_glibc_version(version_str, required_major, minimum_minor):\n    # type: (str, int, int) -> bool\n    # Parse string and check against requested version.\n    #\n    # We use a regexp instead of str.split because we want to discard any\n    # random junk that might come after the minor version -- this might happen\n    # in patched/forked versions of glibc (e.g. Linaro's version of glibc\n    # uses version strings like \"2.20-2014.11\"). See gh-3588.\n    m = re.match(r\"(?P<major>[0-9]+)\\.(?P<minor>[0-9]+)\", version_str)\n    if not m:\n        warnings.warn(\"Expected glibc version with 2 components major.minor,\"\n                      \" got: %s\" % version_str, RuntimeWarning)\n        return False\n    return (int(m.group(\"major\")) == required_major and\n            int(m.group(\"minor\")) >= minimum_minor)\n\n\ndef have_compatible_glibc(required_major, minimum_minor):\n    # type: (int, int) -> bool\n    version_str = glibc_version_string()  # type: Optional[str]\n    if version_str is None:\n        return False\n    return check_glibc_version(version_str, required_major, minimum_minor)\n\n\n# platform.libc_ver regularly returns completely nonsensical glibc\n# versions. E.g. on my computer, platform says:\n#\n#   ~$ python2.7 -c 'import platform; print(platform.libc_ver())'\n#   ('glibc', '2.7')\n#   ~$ python3.5 -c 'import platform; print(platform.libc_ver())'\n#   ('glibc', '2.9')\n#\n# But the truth is:\n#\n#   ~$ ldd --version\n#   ldd (Debian GLIBC 2.22-11) 2.22\n#\n# This is unfortunate, because it means that the linehaul data on libc\n# versions that was generated by pip 8.1.2 and earlier is useless and\n# misleading. Solution: instead of using platform, use our code that actually\n# works.\ndef libc_ver():\n    # type: () -> Tuple[str, str]\n    \"\"\"Try to determine the glibc version\n\n    Returns a tuple of strings (lib, version) which default to empty strings\n    in case the lookup fails.\n    \"\"\"\n    glibc_version = glibc_version_string()\n    if glibc_version is None:\n        return (\"\", \"\")\n    else:\n        return (\"glibc\", glibc_version)\n", "path": "src/pip/_internal/utils/glibc.py"}], "after_files": [{"content": "from __future__ import absolute_import\n\nimport os\nimport re\nimport warnings\n\nfrom pip._internal.utils.typing import MYPY_CHECK_RUNNING\n\nif MYPY_CHECK_RUNNING:\n    from typing import Optional, Tuple\n\n\ndef glibc_version_string():\n    # type: () -> Optional[str]\n    \"Returns glibc version string, or None if not using glibc.\"\n    return glibc_version_string_confstr() or glibc_version_string_ctypes()\n\n\ndef glibc_version_string_confstr():\n    # type: () -> Optional[str]\n    \"Primary implementation of glibc_version_string using os.confstr.\"\n    # os.confstr is quite a bit faster than ctypes.DLL. It's also less likely\n    # to be broken or missing. This strategy is used in the standard library\n    # platform module:\n    # https://github.com/python/cpython/blob/fcf1d003bf4f0100c9d0921ff3d70e1127ca1b71/Lib/platform.py#L175-L183\n    try:\n        # os.confstr(\"CS_GNU_LIBC_VERSION\") returns a string like \"glibc 2.17\":\n        _, version = os.confstr(\"CS_GNU_LIBC_VERSION\").split()\n    except (AttributeError, OSError, ValueError):\n        # os.confstr() or CS_GNU_LIBC_VERSION not available (or a bad value)...\n        return None\n    return version\n\n\ndef glibc_version_string_ctypes():\n    # type: () -> Optional[str]\n    \"Fallback implementation of glibc_version_string using ctypes.\"\n\n    try:\n        import ctypes\n    except ImportError:\n        return None\n\n    # ctypes.CDLL(None) internally calls dlopen(NULL), and as the dlopen\n    # manpage says, \"If filename is NULL, then the returned handle is for the\n    # main program\". This way we can let the linker do the work to figure out\n    # which libc our process is actually using.\n    process_namespace = ctypes.CDLL(None)\n    try:\n        gnu_get_libc_version = process_namespace.gnu_get_libc_version\n    except AttributeError:\n        # Symbol doesn't exist -> therefore, we are not linked to\n        # glibc.\n        return None\n\n    # Call gnu_get_libc_version, which returns a string like \"2.5\"\n    gnu_get_libc_version.restype = ctypes.c_char_p\n    version_str = gnu_get_libc_version()\n    # py2 / py3 compatibility:\n    if not isinstance(version_str, str):\n        version_str = version_str.decode(\"ascii\")\n\n    return version_str\n\n\n# Separated out from have_compatible_glibc for easier unit testing\ndef check_glibc_version(version_str, required_major, minimum_minor):\n    # type: (str, int, int) -> bool\n    # Parse string and check against requested version.\n    #\n    # We use a regexp instead of str.split because we want to discard any\n    # random junk that might come after the minor version -- this might happen\n    # in patched/forked versions of glibc (e.g. Linaro's version of glibc\n    # uses version strings like \"2.20-2014.11\"). See gh-3588.\n    m = re.match(r\"(?P<major>[0-9]+)\\.(?P<minor>[0-9]+)\", version_str)\n    if not m:\n        warnings.warn(\"Expected glibc version with 2 components major.minor,\"\n                      \" got: %s\" % version_str, RuntimeWarning)\n        return False\n    return (int(m.group(\"major\")) == required_major and\n            int(m.group(\"minor\")) >= minimum_minor)\n\n\ndef have_compatible_glibc(required_major, minimum_minor):\n    # type: (int, int) -> bool\n    version_str = glibc_version_string()\n    if version_str is None:\n        return False\n    return check_glibc_version(version_str, required_major, minimum_minor)\n\n\n# platform.libc_ver regularly returns completely nonsensical glibc\n# versions. E.g. on my computer, platform says:\n#\n#   ~$ python2.7 -c 'import platform; print(platform.libc_ver())'\n#   ('glibc', '2.7')\n#   ~$ python3.5 -c 'import platform; print(platform.libc_ver())'\n#   ('glibc', '2.9')\n#\n# But the truth is:\n#\n#   ~$ ldd --version\n#   ldd (Debian GLIBC 2.22-11) 2.22\n#\n# This is unfortunate, because it means that the linehaul data on libc\n# versions that was generated by pip 8.1.2 and earlier is useless and\n# misleading. Solution: instead of using platform, use our code that actually\n# works.\ndef libc_ver():\n    # type: () -> Tuple[str, str]\n    \"\"\"Try to determine the glibc version\n\n    Returns a tuple of strings (lib, version) which default to empty strings\n    in case the lookup fails.\n    \"\"\"\n    glibc_version = glibc_version_string()\n    if glibc_version is None:\n        return (\"\", \"\")\n    else:\n        return (\"glibc\", glibc_version)\n", "path": "src/pip/_internal/utils/glibc.py"}]}