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Editing: site.py
"""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._getuserbase() def _getuserbase(): env_base = os.environ.get("PYTHONUSERBASE", None) if env_base: return env_base # Emscripten, VxWorks, and WASI have no home directories if sys.platform in {"emscripten", "vxworks", "wasi"}: 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, "Python") 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 os.name == 'nt': ver_nodot = sys.winver.replace('.', '') return f'{userbase}\\Python{ver_nodot}\\site-packages' if sys.platform == 'darwin' and sys._framework: return f'{userbase}/lib/python/site-packages' return f'{userbase}/lib/python{version[0]}.{version[1]}/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) if os.sep == '/': libdirs = [sys.platlibdir] if sys.platlibdir != "lib": libdirs.append("lib") for libdir in libdirs: path = os.path.join(prefix, libdir, "python%d.%d" % sys.version_info[:2], "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 '/usr/local' is included in PREFIXES if RPM build is not detected to make packages installed into this location visible. """ _trace("Processing global site-packages") if ENABLE_USER_SITE and 'RPM_BUILD_ROOT' not in os.environ: PREFIXES.insert(0, "/usr/local") 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, Zope Corporation, the Python Software Foundation, 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 enablerlcompleter(): """Enable default readline configuration on interactive prompts, by registering a sys.__interactivehook__. 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. """ def register_readline(): import atexit try: import readline import rlcompleter 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. readline_doc = getattr(readline, '__doc__', '') if readline_doc is not None and 'libedit' in readline_doc: 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: # If no history was loaded, default to .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 = os.path.join(os.path.expanduser('~'), '.python_history') try: readline.read_history_file(history) except OSError: pass def write_history(): try: readline.write_history_file(history) except OSError: # bpo-19891, bpo-41193: Home directory does not exist # or is not writable, or the filesystem is read-only. pass atexit.register(write_history) sys.__interactivehook__ = register_readline 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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