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# -*- coding: utf-8 -*-
# Copyright (C) 2012 The Python Software Foundation.
"""Access to Python's configuration information."""
import codecs
import os
import re
import sys
from os.path import pardir, realpath
import configparser
except ImportError:
import ConfigParser as configparser
__all__ = [
def _safe_realpath(path):
return realpath(path)
except OSError:
return path
if sys.executable:
_PROJECT_BASE = os.path.dirname(_safe_realpath(sys.executable))
# sys.executable can be empty if argv[0] has been changed and Python is
# unable to retrieve the real program name
_PROJECT_BASE = _safe_realpath(os.getcwd())
if == "nt" and "pcbuild" in _PROJECT_BASE[-8:].lower():
_PROJECT_BASE = _safe_realpath(os.path.join(_PROJECT_BASE, pardir))
# PC/VS7.1
if == "nt" and "\\pc\\v" in _PROJECT_BASE[-10:].lower():
_PROJECT_BASE = _safe_realpath(os.path.join(_PROJECT_BASE, pardir, pardir))
# PC/AMD64
if == "nt" and "\\pcbuild\\amd64" in _PROJECT_BASE[-14:].lower():
_PROJECT_BASE = _safe_realpath(os.path.join(_PROJECT_BASE, pardir, pardir))
def is_python_build():
for fn in ("Setup.dist", "Setup.local"):
if os.path.isfile(os.path.join(_PROJECT_BASE, "Modules", fn)):
return True
return False
_PYTHON_BUILD = is_python_build()
_cfg_read = False
def _ensure_cfg_read():
global _cfg_read
if not _cfg_read:
from ..resources import finder
backport_package = __name__.rsplit('.', 1)[0]
_finder = finder(backport_package)
_cfgfile = _finder.find('sysconfig.cfg')
assert _cfgfile, 'sysconfig.cfg exists'
with _cfgfile.as_stream() as s:
for scheme in ('posix_prefix', 'posix_home'):
_SCHEMES.set(scheme, 'include', '{srcdir}/Include')
_SCHEMES.set(scheme, 'platinclude', '{projectbase}/.')
_cfg_read = True
_SCHEMES = configparser.RawConfigParser()
_VAR_REPL = re.compile(r'\{([^{]*?)\}')
def _expand_globals(config):
if config.has_section('globals'):
globals = config.items('globals')
globals = tuple()
sections = config.sections()
for section in sections:
if section == 'globals':
for option, value in globals:
if config.has_option(section, option):
config.set(section, option, value)
# now expanding local variables defined in the cfg file
for section in config.sections():
variables = dict(config.items(section))
def _replacer(matchobj):
name =
if name in variables:
return variables[name]
for option, value in config.items(section):
config.set(section, option, _VAR_REPL.sub(_replacer, value))
# FIXME don't rely on sys.version here, its format is an implementation detail
# of CPython, use sys.version_info or sys.hexversion
_PY_VERSION = sys.version.split()[0]
_PY_VERSION_SHORT = sys.version[:3]
_PREFIX = os.path.normpath(sys.prefix)
_EXEC_PREFIX = os.path.normpath(sys.exec_prefix)
def _subst_vars(path, local_vars):
"""In the string `path`, replace tokens like {some.thing} with the
corresponding value from the map `local_vars`.
If there is no corresponding value, leave the token unchanged.
def _replacer(matchobj):
name =
if name in local_vars:
return local_vars[name]
elif name in os.environ:
return os.environ[name]
return _VAR_REPL.sub(_replacer, path)
def _extend_dict(target_dict, other_dict):
target_keys = target_dict.keys()
for key, value in other_dict.items():
if key in target_keys:
target_dict[key] = value
def _expand_vars(scheme, vars):
res = {}
if vars is None:
vars = {}
_extend_dict(vars, get_config_vars())
for key, value in _SCHEMES.items(scheme):
if in ('posix', 'nt'):
value = os.path.expanduser(value)
res[key] = os.path.normpath(_subst_vars(value, vars))
return res
def format_value(value, vars):
def _replacer(matchobj):
name =
if name in vars:
return vars[name]
return _VAR_REPL.sub(_replacer, value)
def _get_default_scheme():
if == 'posix':
# the default scheme for posix is posix_prefix
return 'posix_prefix'
def _getuserbase():
env_base = os.environ.get("PYTHONUSERBASE", None)
def joinuser(*args):
return os.path.expanduser(os.path.join(*args))
# what about 'os2emx', 'riscos' ?
if == "nt":
base = os.environ.get("APPDATA") or "~"
if env_base:
return env_base
return joinuser(base, "Python")
if sys.platform == "darwin":
framework = get_config_var("PYTHONFRAMEWORK")
if framework:
if env_base:
return env_base
return joinuser("~", "Library", framework, "%d.%d" %
if env_base:
return env_base
return joinuser("~", ".local")
def _parse_makefile(filename, vars=None):
"""Parse a Makefile-style file.
A dictionary containing name/value pairs is returned. If an
optional dictionary is passed in as the second argument, it is
used instead of a new dictionary.
# Regexes needed for parsing Makefile (and similar syntaxes,
# like old-style Setup files).
_variable_rx = re.compile("([a-zA-Z][a-zA-Z0-9_]+)\s*=\s*(.*)")
_findvar1_rx = re.compile(r"\$\(([A-Za-z][A-Za-z0-9_]*)\)")
_findvar2_rx = re.compile(r"\${([A-Za-z][A-Za-z0-9_]*)}")
if vars is None:
vars = {}
done = {}
notdone = {}
with, encoding='utf-8', errors="surrogateescape") as f:
lines = f.readlines()
for line in lines:
if line.startswith('#') or line.strip() == '':
m = _variable_rx.match(line)
if m:
n, v =, 2)
v = v.strip()
# `$$' is a literal `$' in make
tmpv = v.replace('$$', '')
if "$" in tmpv:
notdone[n] = v
v = int(v)
except ValueError:
# insert literal `$'
done[n] = v.replace('$$', '$')
done[n] = v
# do variable interpolation here
variables = list(notdone.keys())
# Variables with a 'PY_' prefix in the makefile. These need to
# be made available without that prefix through sysconfig.
# Special care is needed to ensure that variable expansion works, even
# if the expansion uses the name without a prefix.
renamed_variables = ('CFLAGS', 'LDFLAGS', 'CPPFLAGS')
while len(variables) > 0:
for name in tuple(variables):
value = notdone[name]
m = or
if m is not None:
n =
found = True
if n in done:
item = str(done[n])
elif n in notdone:
# get it on a subsequent round
found = False
elif n in os.environ:
# do it like make: fall back to environment
item = os.environ[n]
elif n in renamed_variables:
if (name.startswith('PY_') and
name[3:] in renamed_variables):
item = ""
elif 'PY_' + n in notdone:
found = False
item = str(done['PY_' + n])
done[n] = item = ""
if found:
after = value[m.end():]
value = value[:m.start()] + item + after
if "$" in after:
notdone[name] = value
value = int(value)
except ValueError:
done[name] = value.strip()
done[name] = value
if (name.startswith('PY_') and
name[3:] in renamed_variables):
name = name[3:]
if name not in done:
done[name] = value
# bogus variable reference (e.g. "prefix=$/opt/python");
# just drop it since we can't deal
done[name] = value
# strip spurious spaces
for k, v in done.items():
if isinstance(v, str):
done[k] = v.strip()
# save the results in the global dictionary
return vars
def get_makefile_filename():
"""Return the path of the Makefile."""
return os.path.join(_PROJECT_BASE, "Makefile")
if hasattr(sys, 'abiflags'):
config_dir_name = 'config-%s%s' % (_PY_VERSION_SHORT, sys.abiflags)
config_dir_name = 'config'
return os.path.join(get_path('stdlib'), config_dir_name, 'Makefile')
def _init_posix(vars):
"""Initialize the module as appropriate for POSIX systems."""
# load the installed Makefile:
makefile = get_makefile_filename()
_parse_makefile(makefile, vars)
except IOError as e:
msg = "invalid Python installation: unable to open %s" % makefile
if hasattr(e, "strerror"):
msg = msg + " (%s)" % e.strerror
raise IOError(msg)
# load the installed pyconfig.h:
config_h = get_config_h_filename()
with open(config_h) as f:
parse_config_h(f, vars)
except IOError as e:
msg = "invalid Python installation: unable to open %s" % config_h
if hasattr(e, "strerror"):
msg = msg + " (%s)" % e.strerror
raise IOError(msg)
# On AIX, there are wrong paths to the linker scripts in the Makefile
# -- these paths are relative to the Python source, but when installed
# the scripts are in another directory.
vars['LDSHARED'] = vars['BLDSHARED']
def _init_non_posix(vars):
"""Initialize the module as appropriate for NT"""
# set basic install directories
vars['LIBDEST'] = get_path('stdlib')
vars['BINLIBDEST'] = get_path('platstdlib')
vars['INCLUDEPY'] = get_path('include')
vars['SO'] = '.pyd'
vars['EXE'] = '.exe'
vars['BINDIR'] = os.path.dirname(_safe_realpath(sys.executable))
# public APIs
def parse_config_h(fp, vars=None):
"""Parse a config.h-style file.
A dictionary containing name/value pairs is returned. If an
optional dictionary is passed in as the second argument, it is
used instead of a new dictionary.
if vars is None:
vars = {}
define_rx = re.compile("#define ([A-Z][A-Za-z0-9_]+) (.*)\n")
undef_rx = re.compile("/[*] #undef ([A-Z][A-Za-z0-9_]+) [*]/\n")
while True:
line = fp.readline()
if not line:
m = define_rx.match(line)
if m:
n, v =, 2)
v = int(v)
except ValueError:
vars[n] = v
m = undef_rx.match(line)
if m:
vars[] = 0
return vars
def get_config_h_filename():
"""Return the path of pyconfig.h."""
if == "nt":
inc_dir = os.path.join(_PROJECT_BASE, "PC")
inc_dir = _PROJECT_BASE
inc_dir = get_path('platinclude')
return os.path.join(inc_dir, 'pyconfig.h')
def get_scheme_names():
"""Return a tuple containing the schemes names."""
return tuple(sorted(_SCHEMES.sections()))
def get_path_names():
"""Return a tuple containing the paths names."""
# xxx see if we want a static list
return _SCHEMES.options('posix_prefix')
def get_paths(scheme=_get_default_scheme(), vars=None, expand=True):
"""Return a mapping containing an install scheme.
``scheme`` is the install scheme name. If not provided, it will
return the default scheme for the current platform.
if expand:
return _expand_vars(scheme, vars)
return dict(_SCHEMES.items(scheme))
def get_path(name, scheme=_get_default_scheme(), vars=None, expand=True):
"""Return a path corresponding to the scheme.
``scheme`` is the install scheme name.
return get_paths(scheme, vars, expand)[name]
def get_config_vars(*args):
"""With no arguments, return a dictionary of all configuration
variables relevant for the current platform.
On Unix, this means every variable defined in Python's installed Makefile;
On Windows and Mac OS it's a much smaller set.
With arguments, return a list of values that result from looking up
each argument in the configuration variable dictionary.
if _CONFIG_VARS is None:
# Normalized versions of prefix and exec_prefix are handy to have;
# in fact, these are the standard versions used most places in the
# distutils2 module.
_CONFIG_VARS['prefix'] = _PREFIX
_CONFIG_VARS['exec_prefix'] = _EXEC_PREFIX
_CONFIG_VARS['py_version'] = _PY_VERSION
_CONFIG_VARS['py_version_short'] = _PY_VERSION_SHORT
_CONFIG_VARS['py_version_nodot'] = _PY_VERSION[0] + _PY_VERSION[2]
_CONFIG_VARS['projectbase'] = _PROJECT_BASE
_CONFIG_VARS['abiflags'] = sys.abiflags
except AttributeError:
# sys.abiflags may not be defined on all platforms.
_CONFIG_VARS['abiflags'] = ''
if in ('nt', 'os2'):
if == 'posix':
# Setting 'userbase' is done below the call to the
# init function to enable using 'get_config_var' in
# the init-function.
if sys.version >= '2.6':
_CONFIG_VARS['userbase'] = _getuserbase()
if 'srcdir' not in _CONFIG_VARS:
_CONFIG_VARS['srcdir'] = _safe_realpath(_CONFIG_VARS['srcdir'])
# Convert srcdir into an absolute path if it appears necessary.
# Normally it is relative to the build directory. However, during
# testing, for example, we might be running a non-installed python
# from a different directory.
if _PYTHON_BUILD and == "posix":
cwd = os.getcwd()
except OSError:
cwd = None
if (not os.path.isabs(_CONFIG_VARS['srcdir']) and
base != cwd):
# srcdir is relative and we are not in the same directory
# as the executable. Assume executable is in the build
# directory and make srcdir absolute.
srcdir = os.path.join(base, _CONFIG_VARS['srcdir'])
_CONFIG_VARS['srcdir'] = os.path.normpath(srcdir)
if sys.platform == 'darwin':
kernel_version = os.uname()[2] # Kernel version (8.4.3)
major_version = int(kernel_version.split('.')[0])
if major_version < 8:
# On macOS before 10.4, check if -arch and -isysroot
# are in CFLAGS or LDFLAGS and remove them if they are.
# This is needed when building extensions on a 10.3 system
# using a universal build of python.
for key in ('LDFLAGS', 'BASECFLAGS',
# a number of derived variables. These need to be
# patched up as well.
flags = _CONFIG_VARS[key]
flags = re.sub('-arch\s+\w+\s', ' ', flags)
flags = re.sub('-isysroot [^ \t]*', ' ', flags)
_CONFIG_VARS[key] = flags
# Allow the user to override the architecture flags using
# an environment variable.
# NOTE: This name was introduced by Apple in OSX 10.5 and
# is used by several scripting languages distributed with
# that OS release.
if 'ARCHFLAGS' in os.environ:
arch = os.environ['ARCHFLAGS']
for key in ('LDFLAGS', 'BASECFLAGS',
# a number of derived variables. These need to be
# patched up as well.
flags = _CONFIG_VARS[key]
flags = re.sub('-arch\s+\w+\s', ' ', flags)
flags = flags + ' ' + arch
_CONFIG_VARS[key] = flags
# If we're on OSX 10.5 or later and the user tries to
# compiles an extension using an SDK that is not present
# on the current machine it is better to not use an SDK
# than to fail.
# The major usecase for this is users using a
# binary installer on OSX 10.6: that installer uses
# the 10.4u SDK, but that SDK is not installed by default
# when you install Xcode.
m ='-isysroot\s+(\S+)', CFLAGS)
if m is not None:
sdk =
if not os.path.exists(sdk):
for key in ('LDFLAGS', 'BASECFLAGS',
# a number of derived variables. These need to be
# patched up as well.
flags = _CONFIG_VARS[key]
flags = re.sub('-isysroot\s+\S+(\s|$)', ' ', flags)
_CONFIG_VARS[key] = flags
if args:
vals = []
for name in args:
return vals
def get_config_var(name):
"""Return the value of a single variable using the dictionary returned by
Equivalent to get_config_vars().get(name)
return get_config_vars().get(name)
def get_platform():
"""Return a string that identifies the current platform.
This is used mainly to distinguish platform-specific build directories and
platform-specific built distributions. Typically includes the OS name
and version and the architecture (as supplied by 'os.uname()'),
although the exact information included depends on the OS; eg. for IRIX
the architecture isn't particularly important (IRIX only runs on SGI
hardware), but for Linux the kernel version isn't particularly
Examples of returned values:
linux-alpha (?)
Windows will return one of:
win-amd64 (64bit Windows on AMD64 (aka x86_64, Intel64, EM64T, etc)
win-ia64 (64bit Windows on Itanium)
win32 (all others - specifically, sys.platform is returned)
For other non-POSIX platforms, currently just returns 'sys.platform'.
if == 'nt':
# sniff sys.version for architecture.
prefix = " bit ("
i = sys.version.find(prefix)
if i == -1:
return sys.platform
j = sys.version.find(")", i)
look = sys.version[i+len(prefix):j].lower()
if look == 'amd64':
return 'win-amd64'
if look == 'itanium':
return 'win-ia64'
return sys.platform
if != "posix" or not hasattr(os, 'uname'):
# XXX what about the architecture? NT is Intel or Alpha,
# Mac OS is M68k or PPC, etc.
return sys.platform
# Try to distinguish various flavours of Unix
osname, host, release, version, machine = os.uname()
# Convert the OS name to lowercase, remove '/' characters
# (to accommodate BSD/OS), and translate spaces (for "Power Macintosh")
osname = osname.lower().replace('/', '')
machine = machine.replace(' ', '_')
machine = machine.replace('/', '-')
if osname[:5] == "linux":
# At least on Linux/Intel, 'machine' is the processor --
# i386, etc.
# XXX what about Alpha, SPARC, etc?
return "%s-%s" % (osname, machine)
elif osname[:5] == "sunos":
if release[0] >= "5": # SunOS 5 == Solaris 2
osname = "solaris"
release = "%d.%s" % (int(release[0]) - 3, release[2:])
# fall through to standard osname-release-machine representation
elif osname[:4] == "irix": # could be "irix64"!
return "%s-%s" % (osname, release)
elif osname[:3] == "aix":
return "%s-%s.%s" % (osname, version, release)
elif osname[:6] == "cygwin":
osname = "cygwin"
rel_re = re.compile(r'[\d.]+')
m = rel_re.match(release)
if m:
release =
elif osname[:6] == "darwin":
# For our purposes, we'll assume that the system version from
# distutils' perspective is what MACOSX_DEPLOYMENT_TARGET is set
# to. This makes the compatibility story a bit more sane because the
# machine is going to compile and link as if it were
cfgvars = get_config_vars()
macver = cfgvars.get('MACOSX_DEPLOYMENT_TARGET')
if True:
# Always calculate the release of the running machine,
# needed to determine if we can build fat binaries or not.
macrelease = macver
# Get the system version. Reading this plist is a documented
# way to get the system version (see the documentation for
# the Gestalt Manager)
f = open('/System/Library/CoreServices/SystemVersion.plist')
except IOError:
# We're on a plain darwin box, fall back to the default
# behaviour.
m ='<key>ProductUserVisibleVersion</key>\s*'
if m is not None:
macrelease = '.'.join('.')[:2])
# else: fall back to the default behaviour
if not macver:
macver = macrelease
if macver:
release = macver
osname = "macosx"
if ((macrelease + '.') >= '10.4.' and
'-arch' in get_config_vars().get('CFLAGS', '').strip()):
# The universal build will build fat binaries, but not on
# systems before 10.4
# Try to detect 4-way universal builds, those have machine-type
# 'universal' instead of 'fat'.
machine = 'fat'
cflags = get_config_vars().get('CFLAGS')
archs = re.findall('-arch\s+(\S+)', cflags)
archs = tuple(sorted(set(archs)))
if len(archs) == 1:
machine = archs[0]
elif archs == ('i386', 'ppc'):
machine = 'fat'
elif archs == ('i386', 'x86_64'):
machine = 'intel'
elif archs == ('i386', 'ppc', 'x86_64'):
machine = 'fat3'
elif archs == ('ppc64', 'x86_64'):
machine = 'fat64'
elif archs == ('i386', 'ppc', 'ppc64', 'x86_64'):
machine = 'universal'
raise ValueError(
"Don't know machine value for archs=%r" % (archs,))
elif machine == 'i386':
# On OSX the machine type returned by uname is always the
# 32-bit variant, even if the executable architecture is
# the 64-bit variant
if sys.maxsize >= 2**32:
machine = 'x86_64'
elif machine in ('PowerPC', 'Power_Macintosh'):
# Pick a sane name for the PPC architecture.
# See 'i386' case
if sys.maxsize >= 2**32:
machine = 'ppc64'
machine = 'ppc'
return "%s-%s-%s" % (osname, release, machine)
def get_python_version():
def _print_dict(title, data):
for index, (key, value) in enumerate(sorted(data.items())):
if index == 0:
print('%s: ' % (title))
print('\t%s = "%s"' % (key, value))
def _main():
"""Display all information sysconfig detains."""
print('Platform: "%s"' % get_platform())
print('Python version: "%s"' % get_python_version())
print('Current installation scheme: "%s"' % _get_default_scheme())
_print_dict('Paths', get_paths())
_print_dict('Variables', get_config_vars())
if __name__ == '__main__':
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