cpython: e0f997a7aaa5 Lib/os.py (original) (raw)

Fix `versionchanged` tags for json.load `versionchanged` tags about 2.7 are useless in 3.x branches.

line wrap: on

line source

r"""OS routines for Mac, NT, or Posix depending on what system we're on. This exports:

#' import sys, errno import stat as st _names = sys.builtin_module_names

Note: more names are added to all later.

all = ["altsep", "curdir", "pardir", "sep", "pathsep", "linesep", "defpath", "name", "path", "devnull", "SEEK_SET", "SEEK_CUR", "SEEK_END"] def _exists(name): return name in globals() def get_exports_list(module): try: return list(module.all) except AttributeError: return [n for n in dir(module) if n[0] != '']

Any new dependencies of the os module and/or changes in path separator

requires updating importlib as well.

if 'posix' in _names: name = 'posix' linesep = '\n' from posix import * try: from posix import _exit except ImportError: pass import posixpath as path import posix all.extend(_get_exports_list(posix)) del posix elif 'nt' in _names: name = 'nt' linesep = '\r\n' from nt import * try: from nt import _exit except ImportError: pass import ntpath as path import nt all.extend(_get_exports_list(nt)) del nt elif 'os2' in _names: name = 'os2' linesep = '\r\n' from os2 import * try: from os2 import _exit except ImportError: pass if sys.version.find('EMX GCC') == -1: import ntpath as path else: import os2emxpath as path from _emx_link import link import os2 all.extend(_get_exports_list(os2)) del os2 elif 'ce' in _names: name = 'ce' linesep = '\r\n' from ce import * try: from ce import _exit except ImportError: pass # We can use the standard Windows path. import ntpath as path import ce all.extend(_get_exports_list(ce)) del ce else: raise ImportError('no os specific module found') sys.modules['os.path'] = path from os.path import (curdir, pardir, sep, pathsep, defpath, extsep, altsep, devnull) del _names

Python uses fixed values for the SEEK_ constants; they are mapped

to native constants if necessary in posixmodule.c

SEEK_SET = 0 SEEK_CUR = 1 SEEK_END = 2 def _get_masked_mode(mode): mask = umask(0) umask(mask) return mode & ~mask

Super directory utilities.

(Inspired by Eric Raymond; the doc strings are mostly his)

def makedirs(name, mode=0o777, exist_ok=False): """makedirs(path [, mode=0o777][, exist_ok=False]) Super-mkdir; create a leaf directory and all intermediate ones. Works like mkdir, except that any intermediate path segment (not just the rightmost) will be created if it does not exist. If the target directory with the same mode as we specified already exists, raises an OSError if exist_ok is False, otherwise no exception is raised. This is recursive. """ head, tail = path.split(name) if not tail: head, tail = path.split(head) if head and tail and not path.exists(head): try: makedirs(head, mode, exist_ok) except OSError as e: # be happy if someone already created the path if e.errno != errno.EEXIST: raise if tail == curdir: # xxx/newdir/. exists if xxx/newdir exists return try: mkdir(name, mode) except OSError as e: if not (e.errno == errno.EEXIST and exist_ok and path.isdir(name) and st.S_IMODE(lstat(name).st_mode) == _get_masked_mode(mode)): raise def removedirs(name): """removedirs(path) Super-rmdir; remove a leaf directory and all empty intermediate ones. Works like rmdir except that, if the leaf directory is successfully removed, directories corresponding to rightmost path segments will be pruned away until either the whole path is consumed or an error occurs. Errors during this latter phase are ignored -- they generally mean that a directory was not empty. """ rmdir(name) head, tail = path.split(name) if not tail: head, tail = path.split(head) while head and tail: try: rmdir(head) except error: break head, tail = path.split(head) def renames(old, new): """renames(old, new) Super-rename; create directories as necessary and delete any left empty. Works like rename, except creation of any intermediate directories needed to make the new pathname good is attempted first. After the rename, directories corresponding to rightmost path segments of the old name will be pruned way until either the whole path is consumed or a nonempty directory is found. Note: this function can fail with the new directory structure made if you lack permissions needed to unlink the leaf directory or file. """ head, tail = path.split(new) if head and tail and not path.exists(head): makedirs(head) rename(old, new) head, tail = path.split(old) if head and tail: try: removedirs(head) except error: pass all.extend(["makedirs", "removedirs", "renames"]) def walk(top, topdown=True, onerror=None, followlinks=False): """Directory tree generator. For each directory in the directory tree rooted at top (including top itself, but excluding '.' and '..'), yields a 3-tuple dirpath, dirnames, filenames dirpath is a string, the path to the directory. dirnames is a list of the names of the subdirectories in dirpath (excluding '.' and '..'). filenames is a list of the names of the non-directory files in dirpath. Note that the names in the lists are just names, with no path components. To get a full path (which begins with top) to a file or directory in dirpath, do os.path.join(dirpath, name). If optional arg 'topdown' is true or not specified, the triple for a directory is generated before the triples for any of its subdirectories (directories are generated top down). If topdown is false, the triple for a directory is generated after the triples for all of its subdirectories (directories are generated bottom up). When topdown is true, the caller can modify the dirnames list in-place (e.g., via del or slice assignment), and walk will only recurse into the subdirectories whose names remain in dirnames; this can be used to prune the search, or to impose a specific order of visiting. Modifying dirnames when topdown is false is ineffective, since the directories in dirnames have already been generated by the time dirnames itself is generated. By default errors from the os.listdir() call are ignored. If optional arg 'onerror' is specified, it should be a function; it will be called with one argument, an os.error instance. It can report the error to continue with the walk, or raise the exception to abort the walk. Note that the filename is available as the filename attribute of the exception object. By default, os.walk does not follow symbolic links to subdirectories on systems that support them. In order to get this functionality, set the optional argument 'followlinks' to true. Caution: if you pass a relative pathname for top, don't change the current working directory between resumptions of walk. walk never changes the current directory, and assumes that the client doesn't either. Example: import os from os.path import join, getsize for root, dirs, files in os.walk('python/Lib/email'): print(root, "consumes", end="") print(sum([getsize(join(root, name)) for name in files]), end="") print("bytes in", len(files), "non-directory files") if 'CVS' in dirs: dirs.remove('CVS') # don't visit CVS directories """ islink, join, isdir = path.islink, path.join, path.isdir # We may not have read permission for top, in which case we can't # get a list of the files the directory contains. os.walk # always suppressed the exception then, rather than blow up for a # minor reason when (say) a thousand readable directories are still # left to visit. That logic is copied here. try: # Note that listdir and error are globals in this module due # to earlier import-*. names = listdir(top) except error as err: if onerror is not None: onerror(err) return dirs, nondirs = [], [] for name in names: if isdir(join(top, name)): dirs.append(name) else: nondirs.append(name) if topdown: yield top, dirs, nondirs for name in dirs: new_path = join(top, name) if followlinks or not islink(new_path): yield from walk(new_path, topdown, onerror, followlinks) if not topdown: yield top, dirs, nondirs all.append("walk") if _exists("openat"): def fwalk(top, topdown=True, onerror=None, followlinks=False): """Directory tree generator. This behaves exactly like walk(), except that it yields a 4-tuple dirpath, dirnames, filenames, dirfd dirpath, dirnames and filenames are identical to walk() output, and dirfd is a file descriptor referring to the directory dirpath. The advantage of walkfd() over walk() is that it's safe against symlink races (when followlinks is False). Caution: Since fwalk() yields file descriptors, those are only valid until the next iteration step, so you should dup() them if you want to keep them for a longer period. Example: import os for root, dirs, files, rootfd in os.fwalk('python/Lib/email'): print(root, "consumes", end="") print(sum([os.fstatat(rootfd, name).st_size for name in files]), end="") print("bytes in", len(files), "non-directory files") if 'CVS' in dirs: dirs.remove('CVS') # don't visit CVS directories """ # Note: To guard against symlink races, we use the standard # lstat()/open()/fstat() trick. orig_st = lstat(top) topfd = open(top, O_RDONLY) try: if (followlinks or (st.S_ISDIR(orig_st.st_mode) and path.samestat(orig_st, fstat(topfd)))): yield from _fwalk(topfd, top, topdown, onerror, followlinks) finally: close(topfd) def _fwalk(topfd, toppath, topdown, onerror, followlinks): # Note: This uses O(depth of the directory tree) file descriptors: if # necessary, it can be adapted to only require O(1) FDs, see issue # #13734. # whether to follow symlinks flag = 0 if followlinks else AT_SYMLINK_NOFOLLOW names = flistdir(topfd) dirs, nondirs = [], [] for name in names: try: # Here, we don't use AT_SYMLINK_NOFOLLOW to be consistent with # walk() which reports symlinks to directories as directories. # We do however check for symlinks before recursing into # a subdirectory. if st.S_ISDIR(fstatat(topfd, name).st_mode): dirs.append(name) else: nondirs.append(name) except FileNotFoundError: try: # Add dangling symlinks, ignore disappeared files if st.S_ISLNK(fstatat(topfd, name, AT_SYMLINK_NOFOLLOW) .st_mode): nondirs.append(name) except FileNotFoundError: continue if topdown: yield toppath, dirs, nondirs, topfd for name in dirs: try: orig_st = fstatat(topfd, name, flag) dirfd = openat(topfd, name, O_RDONLY) except error as err: if onerror is not None: onerror(err) return try: if followlinks or path.samestat(orig_st, fstat(dirfd)): dirpath = path.join(toppath, name) yield from _fwalk(dirfd, dirpath, topdown, onerror, followlinks) finally: close(dirfd) if not topdown: yield toppath, dirs, nondirs, topfd all.append("fwalk")

Make sure os.environ exists, at least

try: environ except NameError: environ = {} def execl(file, *args): """execl(file, *args) Execute the executable file with argument list args, replacing the current process. """ execv(file, args) def execle(file, *args): """execle(file, *args, env) Execute the executable file with argument list args and environment env, replacing the current process. """ env = args[-1] execve(file, args[:-1], env) def execlp(file, *args): """execlp(file, *args) Execute the executable file (which is searched for along $PATH) with argument list args, replacing the current process. """ execvp(file, args) def execlpe(file, *args): """execlpe(file, *args, env) Execute the executable file (which is searched for along $PATH) with argument list args and environment env, replacing the current process. """ env = args[-1] execvpe(file, args[:-1], env) def execvp(file, args): """execvp(file, args) Execute the executable file (which is searched for along $PATH) with argument list args, replacing the current process. args may be a list or tuple of strings. """ _execvpe(file, args) def execvpe(file, args, env): """execvpe(file, args, env) Execute the executable file (which is searched for along $PATH) with argument list args and environment env , replacing the current process. args may be a list or tuple of strings. """ _execvpe(file, args, env) all.extend(["execl","execle","execlp","execlpe","execvp","execvpe"]) def _execvpe(file, args, env=None): if env is not None: exec_func = execve argrest = (args, env) else: exec_func = execv argrest = (args,) env = environ head, tail = path.split(file) if head: exec_func(file, *argrest) return last_exc = saved_exc = None saved_tb = None path_list = get_exec_path(env) if name != 'nt': file = fsencode(file) path_list = map(fsencode, path_list) for dir in path_list: fullname = path.join(dir, file) try: exec_func(fullname, *argrest) except error as e: last_exc = e tb = sys.exc_info()[2] if (e.errno != errno.ENOENT and e.errno != errno.ENOTDIR and saved_exc is None): saved_exc = e saved_tb = tb if saved_exc: raise saved_exc.with_traceback(saved_tb) raise last_exc.with_traceback(tb) def get_exec_path(env=None): """Returns the sequence of directories that will be searched for the named executable (similar to a shell) when launching a process. env must be an environment variable dict or None. If env is None, os.environ will be used. """ # Use a local import instead of a global import to limit the number of # modules loaded at startup: the os module is always loaded at startup by # Python. It may also avoid a bootstrap issue. import warnings if env is None: env = environ # {b'PATH': ...}.get('PATH') and {'PATH': ...}.get(b'PATH') emit a # BytesWarning when using python -b or python -bb: ignore the warning with warnings.catch_warnings(): warnings.simplefilter("ignore", BytesWarning) try: path_list = env.get('PATH') except TypeError: path_list = None if supports_bytes_environ: try: path_listb = env[b'PATH'] except (KeyError, TypeError): pass else: if path_list is not None: raise ValueError( "env cannot contain 'PATH' and b'PATH' keys") path_list = path_listb if path_list is not None and isinstance(path_list, bytes): path_list = fsdecode(path_list) if path_list is None: path_list = defpath return path_list.split(pathsep)

Change environ to automatically call putenv(), unsetenv if they exist.

from collections.abc import MutableMapping class _Environ(MutableMapping): def init(self, data, encodekey, decodekey, encodevalue, decodevalue, putenv, unsetenv): self.encodekey = encodekey self.decodekey = decodekey self.encodevalue = encodevalue self.decodevalue = decodevalue self.putenv = putenv self.unsetenv = unsetenv self._data = data def getitem(self, key): value = self._data[self.encodekey(key)] return self.decodevalue(value) def setitem(self, key, value): key = self.encodekey(key) value = self.encodevalue(value) self.putenv(key, value) self._data[key] = value def delitem(self, key): key = self.encodekey(key) self.unsetenv(key) del self._data[key] def iter(self): for key in self._data: yield self.decodekey(key) def len(self): return len(self._data) def repr(self): return 'environ({{{}}})'.format(', '.join( ('{!r}: {!r}'.format(self.decodekey(key), self.decodevalue(value)) for key, value in self._data.items()))) def copy(self): return dict(self) def setdefault(self, key, value): if key not in self: self[key] = value return self[key] try: _putenv = putenv except NameError: _putenv = lambda key, value: None else: all.append("putenv") try: _unsetenv = unsetenv except NameError: _unsetenv = lambda key: _putenv(key, "") else: all.append("unsetenv") def _createenviron(): if name in ('os2', 'nt'): # Where Env Var Names Must Be UPPERCASE def check_str(value): if not isinstance(value, str): raise TypeError("str expected, not %s" % type(value).name) return value encode = check_str decode = str def encodekey(key): return encode(key).upper() data = {} for key, value in environ.items(): data[encodekey(key)] = value else: # Where Env Var Names Can Be Mixed Case encoding = sys.getfilesystemencoding() def encode(value): if not isinstance(value, str): raise TypeError("str expected, not %s" % type(value).name) return value.encode(encoding, 'surrogateescape') def decode(value): return value.decode(encoding, 'surrogateescape') encodekey = encode data = environ return _Environ(data, encodekey, decode, encode, decode, _putenv, _unsetenv)

unicode environ

environ = _createenviron() del _createenviron def getenv(key, default=None): """Get an environment variable, return None if it doesn't exist. The optional second argument can specify an alternate default. key, default and the result are str.""" return environ.get(key, default) supports_bytes_environ = name not in ('os2', 'nt') all.extend(("getenv", "supports_bytes_environ")) if supports_bytes_environ: def _check_bytes(value): if not isinstance(value, bytes): raise TypeError("bytes expected, not %s" % type(value).name) return value # bytes environ environb = _Environ(environ._data, _check_bytes, bytes, _check_bytes, bytes, _putenv, _unsetenv) del _check_bytes def getenvb(key, default=None): """Get an environment variable, return None if it doesn't exist. The optional second argument can specify an alternate default. key, default and the result are bytes.""" return environb.get(key, default) all.extend(("environb", "getenvb")) def _fscodec(): encoding = sys.getfilesystemencoding() if encoding == 'mbcs': errors = 'strict' else: errors = 'surrogateescape' def fsencode(filename): """ Encode filename to the filesystem encoding with 'surrogateescape' error handler, return bytes unchanged. On Windows, use 'strict' error handler if the file system encoding is 'mbcs' (which is the default encoding). """ if isinstance(filename, bytes): return filename elif isinstance(filename, str): return filename.encode(encoding, errors) else: raise TypeError("expect bytes or str, not %s" % type(filename).name) def fsdecode(filename): """ Decode filename from the filesystem encoding with 'surrogateescape' error handler, return str unchanged. On Windows, use 'strict' error handler if the file system encoding is 'mbcs' (which is the default encoding). """ if isinstance(filename, str): return filename elif isinstance(filename, bytes): return filename.decode(encoding, errors) else: raise TypeError("expect bytes or str, not %s" % type(filename).name) return fsencode, fsdecode fsencode, fsdecode = _fscodec() del _fscodec

Supply spawn*() (probably only for Unix)

if _exists("fork") and not _exists("spawnv") and _exists("execv"): P_WAIT = 0 P_NOWAIT = P_NOWAITO = 1 # XXX Should we support P_DETACH? I suppose it could fork()2 # and close the std I/O streams. Also, P_OVERLAY is the same # as execv()? def _spawnvef(mode, file, args, env, func): # Internal helper; func is the exec() function to use pid = fork() if not pid: # Child try: if env is None: func(file, args) else: func(file, args, env) except: _exit(127) else: # Parent if mode == P_NOWAIT: return pid # Caller is responsible for waiting while 1: wpid, sts = waitpid(pid, 0) if WIFSTOPPED(sts): continue elif WIFSIGNALED(sts): return -WTERMSIG(sts) elif WIFEXITED(sts): return WEXITSTATUS(sts) else: raise error("Not stopped, signaled or exited???") def spawnv(mode, file, args): """spawnv(mode, file, args) -> integer Execute file with arguments from args in a subprocess. If mode == P_NOWAIT return the pid of the process. If mode == P_WAIT return the process's exit code if it exits normally; otherwise return -SIG, where SIG is the signal that killed it. """ return _spawnvef(mode, file, args, None, execv) def spawnve(mode, file, args, env): """spawnve(mode, file, args, env) -> integer Execute file with arguments from args in a subprocess with the specified environment. If mode == P_NOWAIT return the pid of the process. If mode == P_WAIT return the process's exit code if it exits normally; otherwise return -SIG, where SIG is the signal that killed it. """ return _spawnvef(mode, file, args, env, execve) # Note: spawnvp[e] is't currently supported on Windows def spawnvp(mode, file, args): """spawnvp(mode, file, args) -> integer Execute file (which is looked for along $PATH) with arguments from args in a subprocess. If mode == P_NOWAIT return the pid of the process. If mode == P_WAIT return the process's exit code if it exits normally; otherwise return -SIG, where SIG is the signal that killed it. """ return _spawnvef(mode, file, args, None, execvp) def spawnvpe(mode, file, args, env): """spawnvpe(mode, file, args, env) -> integer Execute file (which is looked for along $PATH) with arguments from args in a subprocess with the supplied environment. If mode == P_NOWAIT return the pid of the process. If mode == P_WAIT return the process's exit code if it exits normally; otherwise return -SIG, where SIG is the signal that killed it. """ return _spawnvef(mode, file, args, env, execvpe) if _exists("spawnv"): # These aren't supplied by the basic Windows code # but can be easily implemented in Python def spawnl(mode, file, *args): """spawnl(mode, file, *args) -> integer Execute file with arguments from args in a subprocess. If mode == P_NOWAIT return the pid of the process. If mode == P_WAIT return the process's exit code if it exits normally; otherwise return -SIG, where SIG is the signal that killed it. """ return spawnv(mode, file, args) def spawnle(mode, file, *args): """spawnle(mode, file, *args, env) -> integer Execute file with arguments from args in a subprocess with the supplied environment. If mode == P_NOWAIT return the pid of the process. If mode == P_WAIT return the process's exit code if it exits normally; otherwise return -SIG, where SIG is the signal that killed it. """ env = args[-1] return spawnve(mode, file, args[:-1], env) all.extend(["spawnv", "spawnve", "spawnl", "spawnle",]) if _exists("spawnvp"): # At the moment, Windows doesn't implement spawnvp[e], # so it won't have spawnlp[e] either. def spawnlp(mode, file, *args): """spawnlp(mode, file, *args) -> integer Execute file (which is looked for along $PATH) with arguments from args in a subprocess with the supplied environment. If mode == P_NOWAIT return the pid of the process. If mode == P_WAIT return the process's exit code if it exits normally; otherwise return -SIG, where SIG is the signal that killed it. """ return spawnvp(mode, file, args) def spawnlpe(mode, file, *args): """spawnlpe(mode, file, *args, env) -> integer Execute file (which is looked for along $PATH) with arguments from args in a subprocess with the supplied environment. If mode == P_NOWAIT return the pid of the process. If mode == P_WAIT return the process's exit code if it exits normally; otherwise return -SIG, where SIG is the signal that killed it. """ env = args[-1] return spawnvpe(mode, file, args[:-1], env) all.extend(["spawnvp", "spawnvpe", "spawnlp", "spawnlpe",]) import copyreg as _copyreg def _make_stat_result(tup, dict): return stat_result(tup, dict) def _pickle_stat_result(sr): (type, args) = sr.reduce() return (_make_stat_result, args) try: _copyreg.pickle(stat_result, _pickle_stat_result, _make_stat_result) except NameError: # stat_result may not exist pass def _make_statvfs_result(tup, dict): return statvfs_result(tup, dict) def _pickle_statvfs_result(sr): (type, args) = sr.reduce() return (_make_statvfs_result, args) try: _copyreg.pickle(statvfs_result, _pickle_statvfs_result, _make_statvfs_result) except NameError: # statvfs_result may not exist pass

Supply os.popen()

def popen(cmd, mode="r", buffering=-1): if not isinstance(cmd, str): raise TypeError("invalid cmd type (%s, expected string)" % type(cmd)) if mode not in ("r", "w"): raise ValueError("invalid mode %r" % mode) if buffering == 0 or buffering == None: raise ValueError("popen() does not support unbuffered streams") import subprocess, io if mode == "r": proc = subprocess.Popen(cmd, shell=True, stdout=subprocess.PIPE, bufsize=buffering) return _wrap_close(io.TextIOWrapper(proc.stdout), proc) else: proc = subprocess.Popen(cmd, shell=True, stdin=subprocess.PIPE, bufsize=buffering) return _wrap_close(io.TextIOWrapper(proc.stdin), proc)

Helper for popen() -- a proxy for a file whose close waits for the process

class _wrap_close: def init(self, stream, proc): self._stream = stream self._proc = proc def close(self): self._stream.close() returncode = self._proc.wait() if returncode == 0: return None if name == 'nt': return returncode else: return returncode << 8 # Shift left to match old behavior def enter(self): return self def exit(self, *args): self.close() def getattr(self, name): return getattr(self._stream, name) def iter(self): return iter(self._stream)

Supply os.fdopen()

def fdopen(fd, *args, **kwargs): if not isinstance(fd, int): raise TypeError("invalid fd type (%s, expected integer)" % type(fd)) import io return io.open(fd, *args, **kwargs)