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cpython/Lib/site.py

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"""Append module search paths for third-party packages to sys.path.
****************************************************************
* This module is automatically imported during initialization. *
****************************************************************
This will append site-specific paths to the module search path. On
Unix (including Mac OSX), it starts with sys.prefix and
sys.exec_prefix (if different) and appends
lib/python<version>/site-packages.
On other platforms (such as Windows), it tries each of the
prefixes directly, as well as with lib/site-packages appended. The
resulting directories, if they exist, are appended to sys.path, and
also inspected for path configuration files.
If a file named "pyvenv.cfg" exists one directory above sys.executable,
sys.prefix and sys.exec_prefix are set to that directory and
it is also checked for site-packages (sys.base_prefix and
sys.base_exec_prefix will always be the "real" prefixes of the Python
installation). If "pyvenv.cfg" (a bootstrap configuration file) contains
the key "include-system-site-packages" set to anything other than "false"
(case-insensitive), the system-level prefixes will still also be
searched for site-packages; otherwise they won't.
All of the resulting site-specific directories, if they exist, are
appended to sys.path, and also inspected for path configuration
files.
A path configuration file is a file whose name has the form
<package>.pth; its contents are additional directories (one per line)
to be added to sys.path. Non-existing directories (or
non-directories) are never added to sys.path; no directory is added to
sys.path more than once. Blank lines and lines beginning with
'#' are skipped. Lines starting with 'import' are executed.
For example, suppose sys.prefix and sys.exec_prefix are set to
/usr/local and there is a directory /usr/local/lib/python2.5/site-packages
with three subdirectories, foo, bar and spam, and two path
configuration files, foo.pth and bar.pth. Assume foo.pth contains the
following:
# foo package configuration
foo
bar
bletch
and bar.pth contains:
# bar package configuration
bar
Then the following directories are added to sys.path, in this order:
/usr/local/lib/python2.5/site-packages/bar
/usr/local/lib/python2.5/site-packages/foo
Note that bletch is omitted because it doesn't exist; bar precedes foo
because bar.pth comes alphabetically before foo.pth; and spam is
omitted because it is not mentioned in either path configuration file.
The readline module is also automatically configured to enable
completion for systems that support it. This can be overridden in
sitecustomize, usercustomize or PYTHONSTARTUP. Starting Python in
isolated mode (-I) disables automatic readline configuration.
After these operations, an attempt is made to import a module
named sitecustomize, which can perform arbitrary additional
site-specific customizations. If this import fails with an
ImportError exception, it is silently ignored.
"""
import sys
import os
import builtins
import _sitebuiltins
import io
import stat
# Prefixes for site-packages; add additional prefixes like /usr/local here
PREFIXES = [sys.prefix, sys.exec_prefix]
# Enable per user site-packages directory
# set it to False to disable the feature or True to force the feature
ENABLE_USER_SITE = None
# for distutils.commands.install
# These values are initialized by the getuserbase() and getusersitepackages()
# functions, through the main() function when Python starts.
USER_SITE = None
USER_BASE = None
def _trace(message):
if sys.flags.verbose:
print(message, file=sys.stderr)
def makepath(*paths):
dir = os.path.join(*paths)
try:
dir = os.path.abspath(dir)
except OSError:
pass
return dir, os.path.normcase(dir)
def abs_paths():
"""Set all module __file__ and __cached__ attributes to an absolute path"""
for m in set(sys.modules.values()):
loader_module = None
try:
loader_module = m.__loader__.__module__
except AttributeError:
try:
loader_module = m.__spec__.loader.__module__
except AttributeError:
pass
if loader_module not in {'_frozen_importlib', '_frozen_importlib_external'}:
continue # don't mess with a PEP 302-supplied __file__
try:
m.__file__ = os.path.abspath(m.__file__)
except (AttributeError, OSError, TypeError):
pass
try:
m.__cached__ = os.path.abspath(m.__cached__)
except (AttributeError, OSError, TypeError):
pass
def removeduppaths():
""" Remove duplicate entries from sys.path along with making them
absolute"""
# This ensures that the initial path provided by the interpreter contains
# only absolute pathnames, even if we're running from the build directory.
L = []
known_paths = set()
for dir in sys.path:
# Filter out duplicate paths (on case-insensitive file systems also
# if they only differ in case); turn relative paths into absolute
# paths.
dir, dircase = makepath(dir)
if dircase not in known_paths:
L.append(dir)
known_paths.add(dircase)
sys.path[:] = L
return known_paths
def _init_pathinfo():
"""Return a set containing all existing file system items from sys.path."""
d = set()
for item in sys.path:
try:
if os.path.exists(item):
_, itemcase = makepath(item)
d.add(itemcase)
except TypeError:
continue
return d
def addpackage(sitedir, name, known_paths):
"""Process a .pth file within the site-packages directory:
For each line in the file, either combine it with sitedir to a path
and add that to known_paths, or execute it if it starts with 'import '.
"""
if known_paths is None:
known_paths = _init_pathinfo()
reset = True
else:
reset = False
fullname = os.path.join(sitedir, name)
try:
st = os.lstat(fullname)
except OSError:
return
if ((getattr(st, 'st_flags', 0) & stat.UF_HIDDEN) or
(getattr(st, 'st_file_attributes', 0) & stat.FILE_ATTRIBUTE_HIDDEN)):
_trace(f"Skipping hidden .pth file: {fullname!r}")
return
_trace(f"Processing .pth file: {fullname!r}")
try:
with io.open_code(fullname) as f:
pth_content = f.read()
except OSError:
return
try:
# Accept BOM markers in .pth files as we do in source files
# (Windows PowerShell 5.1 makes it hard to emit UTF-8 files without a BOM)
pth_content = pth_content.decode("utf-8-sig")
except UnicodeDecodeError:
# Fallback to locale encoding for backward compatibility.
# We will deprecate this fallback in the future.
import locale
pth_content = pth_content.decode(locale.getencoding())
_trace(f"Cannot read {fullname!r} as UTF-8. "
f"Using fallback encoding {locale.getencoding()!r}")
for n, line in enumerate(pth_content.splitlines(), 1):
if line.startswith("#"):
continue
if line.strip() == "":
continue
try:
if line.startswith(("import ", "import\t")):
exec(line)
continue
line = line.rstrip()
dir, dircase = makepath(sitedir, line)
if dircase not in known_paths and os.path.exists(dir):
sys.path.append(dir)
known_paths.add(dircase)
except Exception as exc:
print(f"Error processing line {n:d} of {fullname}:\n",
file=sys.stderr)
import traceback
for record in traceback.format_exception(exc):
for line in record.splitlines():
print(' '+line, file=sys.stderr)
print("\nRemainder of file ignored", file=sys.stderr)
break
if reset:
known_paths = None
return known_paths
def addsitedir(sitedir, known_paths=None):
"""Add 'sitedir' argument to sys.path if missing and handle .pth files in
'sitedir'"""
_trace(f"Adding directory: {sitedir!r}")
if known_paths is None:
known_paths = _init_pathinfo()
reset = True
else:
reset = False
sitedir, sitedircase = makepath(sitedir)
if not sitedircase in known_paths:
sys.path.append(sitedir) # Add path component
known_paths.add(sitedircase)
try:
names = os.listdir(sitedir)
except OSError:
return
names = [name for name in names
if name.endswith(".pth") and not name.startswith(".")]
for name in sorted(names):
addpackage(sitedir, name, known_paths)
if reset:
known_paths = None
return known_paths
def check_enableusersite():
"""Check if user site directory is safe for inclusion
The function tests for the command line flag (including environment var),
process uid/gid equal to effective uid/gid.
None: Disabled for security reasons
False: Disabled by user (command line option)
True: Safe and enabled
"""
if sys.flags.no_user_site:
return False
if hasattr(os, "getuid") and hasattr(os, "geteuid"):
# check process uid == effective uid
if os.geteuid() != os.getuid():
return None
if hasattr(os, "getgid") and hasattr(os, "getegid"):
# check process gid == effective gid
if os.getegid() != os.getgid():
return None
return True
# NOTE: sysconfig and it's dependencies are relatively large but site module
# needs very limited part of them.
# To speedup startup time, we have copy of them.
#
# See https://bugs.python.org/issue29585
# Copy of sysconfig._get_implementation()
def _get_implementation():
return 'Python'
# Copy of sysconfig._getuserbase()
def _getuserbase():
env_base = os.environ.get("PYTHONUSERBASE", None)
if env_base:
return env_base
# Emscripten, iOS, tvOS, VxWorks, WASI, and watchOS have no home directories
if sys.platform in {"emscripten", "ios", "tvos", "vxworks", "wasi", "watchos"}:
return None
def joinuser(*args):
return os.path.expanduser(os.path.join(*args))
if os.name == "nt":
base = os.environ.get("APPDATA") or "~"
return joinuser(base, _get_implementation())
if sys.platform == "darwin" and sys._framework:
return joinuser("~", "Library", sys._framework,
"%d.%d" % sys.version_info[:2])
return joinuser("~", ".local")
# Same to sysconfig.get_path('purelib', os.name+'_user')
def _get_path(userbase):
version = sys.version_info
if hasattr(sys, 'abiflags') and 't' in sys.abiflags:
abi_thread = 't'
else:
abi_thread = ''
implementation = _get_implementation()
implementation_lower = implementation.lower()
if os.name == 'nt':
ver_nodot = sys.winver.replace('.', '')
return f'{userbase}\\{implementation}{ver_nodot}\\site-packages'
if sys.platform == 'darwin' and sys._framework:
return f'{userbase}/lib/{implementation_lower}/site-packages'
return f'{userbase}/lib/python{version[0]}.{version[1]}{abi_thread}/site-packages'
def getuserbase():
"""Returns the `user base` directory path.
The `user base` directory can be used to store data. If the global
variable ``USER_BASE`` is not initialized yet, this function will also set
it.
"""
global USER_BASE
if USER_BASE is None:
USER_BASE = _getuserbase()
return USER_BASE
def getusersitepackages():
"""Returns the user-specific site-packages directory path.
If the global variable ``USER_SITE`` is not initialized yet, this
function will also set it.
"""
global USER_SITE, ENABLE_USER_SITE
userbase = getuserbase() # this will also set USER_BASE
if USER_SITE is None:
if userbase is None:
ENABLE_USER_SITE = False # disable user site and return None
else:
USER_SITE = _get_path(userbase)
return USER_SITE
def addusersitepackages(known_paths):
"""Add a per user site-package to sys.path
Each user has its own python directory with site-packages in the
home directory.
"""
# get the per user site-package path
# this call will also make sure USER_BASE and USER_SITE are set
_trace("Processing user site-packages")
user_site = getusersitepackages()
if ENABLE_USER_SITE and os.path.isdir(user_site):
addsitedir(user_site, known_paths)
return known_paths
def getsitepackages(prefixes=None):
"""Returns a list containing all global site-packages directories.
For each directory present in ``prefixes`` (or the global ``PREFIXES``),
this function will find its `site-packages` subdirectory depending on the
system environment, and will return a list of full paths.
"""
sitepackages = []
seen = set()
if prefixes is None:
prefixes = PREFIXES
for prefix in prefixes:
if not prefix or prefix in seen:
continue
seen.add(prefix)
implementation = _get_implementation().lower()
ver = sys.version_info
if hasattr(sys, 'abiflags') and 't' in sys.abiflags:
abi_thread = 't'
else:
abi_thread = ''
if os.sep == '/':
libdirs = [sys.platlibdir]
if sys.platlibdir != "lib":
libdirs.append("lib")
for libdir in libdirs:
path = os.path.join(prefix, libdir,
f"{implementation}{ver[0]}.{ver[1]}{abi_thread}",
"site-packages")
sitepackages.append(path)
else:
sitepackages.append(prefix)
sitepackages.append(os.path.join(prefix, "Lib", "site-packages"))
return sitepackages
def addsitepackages(known_paths, prefixes=None):
"""Add site-packages to sys.path"""
_trace("Processing global site-packages")
for sitedir in getsitepackages(prefixes):
if os.path.isdir(sitedir):
addsitedir(sitedir, known_paths)
return known_paths
def setquit():
"""Define new builtins 'quit' and 'exit'.
These are objects which make the interpreter exit when called.
The repr of each object contains a hint at how it works.
"""
if os.sep == '\\':
eof = 'Ctrl-Z plus Return'
else:
eof = 'Ctrl-D (i.e. EOF)'
builtins.quit = _sitebuiltins.Quitter('quit', eof)
builtins.exit = _sitebuiltins.Quitter('exit', eof)
def setcopyright():
"""Set 'copyright' and 'credits' in builtins"""
builtins.copyright = _sitebuiltins._Printer("copyright", sys.copyright)
builtins.credits = _sitebuiltins._Printer("credits", """\
Thanks to CWI, CNRI, BeOpen.com, Zope Corporation and a cast of thousands
for supporting Python development. See www.python.org for more information.""")
files, dirs = [], []
# Not all modules are required to have a __file__ attribute. See
# PEP 420 for more details.
here = getattr(sys, '_stdlib_dir', None)
if not here and hasattr(os, '__file__'):
here = os.path.dirname(os.__file__)
if here:
files.extend(["LICENSE.txt", "LICENSE"])
dirs.extend([os.path.join(here, os.pardir), here, os.curdir])
builtins.license = _sitebuiltins._Printer(
"license",
"See https://www.python.org/psf/license/",
files, dirs)
def sethelper():
builtins.help = _sitebuiltins._Helper()
def gethistoryfile():
"""Check if the PYTHON_HISTORY environment variable is set and define
it as the .python_history file. If PYTHON_HISTORY is not set, use the
default .python_history file.
"""
if not sys.flags.ignore_environment:
history = os.environ.get("PYTHON_HISTORY")
if history:
return history
return os.path.join(os.path.expanduser('~'),
'.python_history')
def enablerlcompleter():
"""Enable default readline configuration on interactive prompts, by
registering a sys.__interactivehook__.
"""
sys.__interactivehook__ = register_readline
def register_readline():
"""Configure readline completion on interactive prompts.
If the readline module can be imported, the hook will set the Tab key
as completion key and register ~/.python_history as history file.
This can be overridden in the sitecustomize or usercustomize module,
or in a PYTHONSTARTUP file.
"""
import atexit
try:
import readline
import rlcompleter
import _pyrepl.readline
import _pyrepl.unix_console
except ImportError:
return
# Reading the initialization (config) file may not be enough to set a
# completion key, so we set one first and then read the file.
if readline.backend == 'editline':
readline.parse_and_bind('bind ^I rl_complete')
else:
readline.parse_and_bind('tab: complete')
try:
readline.read_init_file()
except OSError:
# An OSError here could have many causes, but the most likely one
# is that there's no .inputrc file (or .editrc file in the case of
# Mac OS X + libedit) in the expected location. In that case, we
# want to ignore the exception.
pass
if readline.get_current_history_length() == 0:
from _pyrepl.main import CAN_USE_PYREPL
# If no history was loaded, default to .python_history,
# or PYTHON_HISTORY.
# The guard is necessary to avoid doubling history size at
# each interpreter exit when readline was already configured
# through a PYTHONSTARTUP hook, see:
# http://bugs.python.org/issue5845#msg198636
history = gethistoryfile()
if os.getenv("PYTHON_BASIC_REPL") or not CAN_USE_PYREPL:
readline_module = readline
else:
readline_module = _pyrepl.readline
try:
readline_module.read_history_file(history)
except (OSError,* _pyrepl.unix_console._error):
pass
def write_history():
try:
readline_module.write_history_file(history)
except (FileNotFoundError, PermissionError):
# home directory does not exist or is not writable
# https://bugs.python.org/issue19891
pass
atexit.register(write_history)
def venv(known_paths):
global PREFIXES, ENABLE_USER_SITE
env = os.environ
if sys.platform == 'darwin' and '__PYVENV_LAUNCHER__' in env:
executable = sys._base_executable = os.environ['__PYVENV_LAUNCHER__']
else:
executable = sys.executable
exe_dir = os.path.dirname(os.path.abspath(executable))
site_prefix = os.path.dirname(exe_dir)
sys._home = None
conf_basename = 'pyvenv.cfg'
candidate_conf = next(
(
conffile for conffile in (
os.path.join(exe_dir, conf_basename),
os.path.join(site_prefix, conf_basename)
)
if os.path.isfile(conffile)
),
None
)
if candidate_conf:
virtual_conf = candidate_conf
system_site = "true"
# Issue 25185: Use UTF-8, as that's what the venv module uses when
# writing the file.
with open(virtual_conf, encoding='utf-8') as f:
for line in f:
if '=' in line:
key, _, value = line.partition('=')
key = key.strip().lower()
value = value.strip()
if key == 'include-system-site-packages':
system_site = value.lower()
elif key == 'home':
sys._home = value
sys.prefix = sys.exec_prefix = site_prefix
# Doing this here ensures venv takes precedence over user-site
addsitepackages(known_paths, [sys.prefix])
# addsitepackages will process site_prefix again if its in PREFIXES,
# but that's ok; known_paths will prevent anything being added twice
if system_site == "true":
PREFIXES.insert(0, sys.prefix)
else:
PREFIXES = [sys.prefix]
ENABLE_USER_SITE = False
return known_paths
def execsitecustomize():
"""Run custom site specific code, if available."""
try:
try:
import sitecustomize
except ImportError as exc:
if exc.name == 'sitecustomize':
pass
else:
raise
except Exception as err:
if sys.flags.verbose:
sys.excepthook(*sys.exc_info())
else:
sys.stderr.write(
"Error in sitecustomize; set PYTHONVERBOSE for traceback:\n"
"%s: %s\n" %
(err.__class__.__name__, err))
def execusercustomize():
"""Run custom user specific code, if available."""
try:
try:
import usercustomize
except ImportError as exc:
if exc.name == 'usercustomize':
pass
else:
raise
except Exception as err:
if sys.flags.verbose:
sys.excepthook(*sys.exc_info())
else:
sys.stderr.write(
"Error in usercustomize; set PYTHONVERBOSE for traceback:\n"
"%s: %s\n" %
(err.__class__.__name__, err))
def main():
"""Add standard site-specific directories to the module search path.
This function is called automatically when this module is imported,
unless the python interpreter was started with the -S flag.
"""
global ENABLE_USER_SITE
orig_path = sys.path[:]
known_paths = removeduppaths()
if orig_path != sys.path:
# removeduppaths() might make sys.path absolute.
# fix __file__ and __cached__ of already imported modules too.
abs_paths()
known_paths = venv(known_paths)
if ENABLE_USER_SITE is None:
ENABLE_USER_SITE = check_enableusersite()
known_paths = addusersitepackages(known_paths)
known_paths = addsitepackages(known_paths)
setquit()
setcopyright()
sethelper()
if not sys.flags.isolated:
enablerlcompleter()
execsitecustomize()
if ENABLE_USER_SITE:
execusercustomize()
# Prevent extending of sys.path when python was started with -S and
# site is imported later.
if not sys.flags.no_site:
main()
def _script():
help = """\
%s [--user-base] [--user-site]
Without arguments print some useful information
With arguments print the value of USER_BASE and/or USER_SITE separated
by '%s'.
Exit codes with --user-base or --user-site:
0 - user site directory is enabled
1 - user site directory is disabled by user
2 - user site directory is disabled by super user
or for security reasons
>2 - unknown error
"""
args = sys.argv[1:]
if not args:
user_base = getuserbase()
user_site = getusersitepackages()
print("sys.path = [")
for dir in sys.path:
print(" %r," % (dir,))
print("]")
def exists(path):
if path is not None and os.path.isdir(path):
return "exists"
else:
return "doesn't exist"
print(f"USER_BASE: {user_base!r} ({exists(user_base)})")
print(f"USER_SITE: {user_site!r} ({exists(user_site)})")
print(f"ENABLE_USER_SITE: {ENABLE_USER_SITE!r}")
sys.exit(0)
buffer = []
if '--user-base' in args:
buffer.append(USER_BASE)
if '--user-site' in args:
buffer.append(USER_SITE)
if buffer:
print(os.pathsep.join(buffer))
if ENABLE_USER_SITE:
sys.exit(0)
elif ENABLE_USER_SITE is False:
sys.exit(1)
elif ENABLE_USER_SITE is None:
sys.exit(2)
else:
sys.exit(3)
else:
import textwrap
print(textwrap.dedent(help % (sys.argv[0], os.pathsep)))
sys.exit(10)
if __name__ == '__main__':
_script()
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