Saved and restored logging._handlerList at the same time as saving/restoring logging...
[python.git] / Lib / os.py
blob31002acb75b0106d7659f140df8f52e666c30b5d
1 r"""OS routines for Mac, NT, or Posix depending on what system we're on.
3 This exports:
4 - all functions from posix, nt, os2, mac, or ce, e.g. unlink, stat, etc.
5 - os.path is one of the modules posixpath, ntpath, or macpath
6 - os.name is 'posix', 'nt', 'os2', 'mac', 'ce' or 'riscos'
7 - os.curdir is a string representing the current directory ('.' or ':')
8 - os.pardir is a string representing the parent directory ('..' or '::')
9 - os.sep is the (or a most common) pathname separator ('/' or ':' or '\\')
10 - os.extsep is the extension separator ('.' or '/')
11 - os.altsep is the alternate pathname separator (None or '/')
12 - os.pathsep is the component separator used in $PATH etc
13 - os.linesep is the line separator in text files ('\r' or '\n' or '\r\n')
14 - os.defpath is the default search path for executables
15 - os.devnull is the file path of the null device ('/dev/null', etc.)
17 Programs that import and use 'os' stand a better chance of being
18 portable between different platforms. Of course, they must then
19 only use functions that are defined by all platforms (e.g., unlink
20 and opendir), and leave all pathname manipulation to os.path
21 (e.g., split and join).
22 """
26 import sys
28 _names = sys.builtin_module_names
30 # Note: more names are added to __all__ later.
31 __all__ = ["altsep", "curdir", "pardir", "sep", "pathsep", "linesep",
32 "defpath", "name", "path", "devnull",
33 "SEEK_SET", "SEEK_CUR", "SEEK_END"]
35 def _get_exports_list(module):
36 try:
37 return list(module.__all__)
38 except AttributeError:
39 return [n for n in dir(module) if n[0] != '_']
41 if 'posix' in _names:
42 name = 'posix'
43 linesep = '\n'
44 from posix import *
45 try:
46 from posix import _exit
47 except ImportError:
48 pass
49 import posixpath as path
51 import posix
52 __all__.extend(_get_exports_list(posix))
53 del posix
55 elif 'nt' in _names:
56 name = 'nt'
57 linesep = '\r\n'
58 from nt import *
59 try:
60 from nt import _exit
61 except ImportError:
62 pass
63 import ntpath as path
65 import nt
66 __all__.extend(_get_exports_list(nt))
67 del nt
69 elif 'os2' in _names:
70 name = 'os2'
71 linesep = '\r\n'
72 from os2 import *
73 try:
74 from os2 import _exit
75 except ImportError:
76 pass
77 if sys.version.find('EMX GCC') == -1:
78 import ntpath as path
79 else:
80 import os2emxpath as path
81 from _emx_link import link
83 import os2
84 __all__.extend(_get_exports_list(os2))
85 del os2
87 elif 'mac' in _names:
88 name = 'mac'
89 linesep = '\r'
90 from mac import *
91 try:
92 from mac import _exit
93 except ImportError:
94 pass
95 import macpath as path
97 import mac
98 __all__.extend(_get_exports_list(mac))
99 del mac
101 elif 'ce' in _names:
102 name = 'ce'
103 linesep = '\r\n'
104 from ce import *
105 try:
106 from ce import _exit
107 except ImportError:
108 pass
109 # We can use the standard Windows path.
110 import ntpath as path
112 import ce
113 __all__.extend(_get_exports_list(ce))
114 del ce
116 elif 'riscos' in _names:
117 name = 'riscos'
118 linesep = '\n'
119 from riscos import *
120 try:
121 from riscos import _exit
122 except ImportError:
123 pass
124 import riscospath as path
126 import riscos
127 __all__.extend(_get_exports_list(riscos))
128 del riscos
130 else:
131 raise ImportError, 'no os specific module found'
133 sys.modules['os.path'] = path
134 from os.path import (curdir, pardir, sep, pathsep, defpath, extsep, altsep,
135 devnull)
137 del _names
139 # Python uses fixed values for the SEEK_ constants; they are mapped
140 # to native constants if necessary in posixmodule.c
141 SEEK_SET = 0
142 SEEK_CUR = 1
143 SEEK_END = 2
147 # Super directory utilities.
148 # (Inspired by Eric Raymond; the doc strings are mostly his)
150 def makedirs(name, mode=0777):
151 """makedirs(path [, mode=0777])
153 Super-mkdir; create a leaf directory and all intermediate ones.
154 Works like mkdir, except that any intermediate path segment (not
155 just the rightmost) will be created if it does not exist. This is
156 recursive.
159 head, tail = path.split(name)
160 if not tail:
161 head, tail = path.split(head)
162 if head and tail and not path.exists(head):
163 makedirs(head, mode)
164 if tail == curdir: # xxx/newdir/. exists if xxx/newdir exists
165 return
166 mkdir(name, mode)
168 def removedirs(name):
169 """removedirs(path)
171 Super-rmdir; remove a leaf directory and all empty intermediate
172 ones. Works like rmdir except that, if the leaf directory is
173 successfully removed, directories corresponding to rightmost path
174 segments will be pruned away until either the whole path is
175 consumed or an error occurs. Errors during this latter phase are
176 ignored -- they generally mean that a directory was not empty.
179 rmdir(name)
180 head, tail = path.split(name)
181 if not tail:
182 head, tail = path.split(head)
183 while head and tail:
184 try:
185 rmdir(head)
186 except error:
187 break
188 head, tail = path.split(head)
190 def renames(old, new):
191 """renames(old, new)
193 Super-rename; create directories as necessary and delete any left
194 empty. Works like rename, except creation of any intermediate
195 directories needed to make the new pathname good is attempted
196 first. After the rename, directories corresponding to rightmost
197 path segments of the old name will be pruned way until either the
198 whole path is consumed or a nonempty directory is found.
200 Note: this function can fail with the new directory structure made
201 if you lack permissions needed to unlink the leaf directory or
202 file.
205 head, tail = path.split(new)
206 if head and tail and not path.exists(head):
207 makedirs(head)
208 rename(old, new)
209 head, tail = path.split(old)
210 if head and tail:
211 try:
212 removedirs(head)
213 except error:
214 pass
216 __all__.extend(["makedirs", "removedirs", "renames"])
218 def walk(top, topdown=True, onerror=None):
219 """Directory tree generator.
221 For each directory in the directory tree rooted at top (including top
222 itself, but excluding '.' and '..'), yields a 3-tuple
224 dirpath, dirnames, filenames
226 dirpath is a string, the path to the directory. dirnames is a list of
227 the names of the subdirectories in dirpath (excluding '.' and '..').
228 filenames is a list of the names of the non-directory files in dirpath.
229 Note that the names in the lists are just names, with no path components.
230 To get a full path (which begins with top) to a file or directory in
231 dirpath, do os.path.join(dirpath, name).
233 If optional arg 'topdown' is true or not specified, the triple for a
234 directory is generated before the triples for any of its subdirectories
235 (directories are generated top down). If topdown is false, the triple
236 for a directory is generated after the triples for all of its
237 subdirectories (directories are generated bottom up).
239 When topdown is true, the caller can modify the dirnames list in-place
240 (e.g., via del or slice assignment), and walk will only recurse into the
241 subdirectories whose names remain in dirnames; this can be used to prune
242 the search, or to impose a specific order of visiting. Modifying
243 dirnames when topdown is false is ineffective, since the directories in
244 dirnames have already been generated by the time dirnames itself is
245 generated.
247 By default errors from the os.listdir() call are ignored. If
248 optional arg 'onerror' is specified, it should be a function; it
249 will be called with one argument, an os.error instance. It can
250 report the error to continue with the walk, or raise the exception
251 to abort the walk. Note that the filename is available as the
252 filename attribute of the exception object.
254 Caution: if you pass a relative pathname for top, don't change the
255 current working directory between resumptions of walk. walk never
256 changes the current directory, and assumes that the client doesn't
257 either.
259 Example:
261 from os.path import join, getsize
262 for root, dirs, files in walk('python/Lib/email'):
263 print root, "consumes",
264 print sum([getsize(join(root, name)) for name in files]),
265 print "bytes in", len(files), "non-directory files"
266 if 'CVS' in dirs:
267 dirs.remove('CVS') # don't visit CVS directories
270 from os.path import join, isdir, islink
272 # We may not have read permission for top, in which case we can't
273 # get a list of the files the directory contains. os.path.walk
274 # always suppressed the exception then, rather than blow up for a
275 # minor reason when (say) a thousand readable directories are still
276 # left to visit. That logic is copied here.
277 try:
278 # Note that listdir and error are globals in this module due
279 # to earlier import-*.
280 names = listdir(top)
281 except error, err:
282 if onerror is not None:
283 onerror(err)
284 return
286 dirs, nondirs = [], []
287 for name in names:
288 if isdir(join(top, name)):
289 dirs.append(name)
290 else:
291 nondirs.append(name)
293 if topdown:
294 yield top, dirs, nondirs
295 for name in dirs:
296 path = join(top, name)
297 if not islink(path):
298 for x in walk(path, topdown, onerror):
299 yield x
300 if not topdown:
301 yield top, dirs, nondirs
303 __all__.append("walk")
305 # Make sure os.environ exists, at least
306 try:
307 environ
308 except NameError:
309 environ = {}
311 def execl(file, *args):
312 """execl(file, *args)
314 Execute the executable file with argument list args, replacing the
315 current process. """
316 execv(file, args)
318 def execle(file, *args):
319 """execle(file, *args, env)
321 Execute the executable file with argument list args and
322 environment env, replacing the current process. """
323 env = args[-1]
324 execve(file, args[:-1], env)
326 def execlp(file, *args):
327 """execlp(file, *args)
329 Execute the executable file (which is searched for along $PATH)
330 with argument list args, replacing the current process. """
331 execvp(file, args)
333 def execlpe(file, *args):
334 """execlpe(file, *args, env)
336 Execute the executable file (which is searched for along $PATH)
337 with argument list args and environment env, replacing the current
338 process. """
339 env = args[-1]
340 execvpe(file, args[:-1], env)
342 def execvp(file, args):
343 """execp(file, args)
345 Execute the executable file (which is searched for along $PATH)
346 with argument list args, replacing the current process.
347 args may be a list or tuple of strings. """
348 _execvpe(file, args)
350 def execvpe(file, args, env):
351 """execvpe(file, args, env)
353 Execute the executable file (which is searched for along $PATH)
354 with argument list args and environment env , replacing the
355 current process.
356 args may be a list or tuple of strings. """
357 _execvpe(file, args, env)
359 __all__.extend(["execl","execle","execlp","execlpe","execvp","execvpe"])
361 def _execvpe(file, args, env=None):
362 from errno import ENOENT, ENOTDIR
364 if env is not None:
365 func = execve
366 argrest = (args, env)
367 else:
368 func = execv
369 argrest = (args,)
370 env = environ
372 head, tail = path.split(file)
373 if head:
374 func(file, *argrest)
375 return
376 if 'PATH' in env:
377 envpath = env['PATH']
378 else:
379 envpath = defpath
380 PATH = envpath.split(pathsep)
381 saved_exc = None
382 saved_tb = None
383 for dir in PATH:
384 fullname = path.join(dir, file)
385 try:
386 func(fullname, *argrest)
387 except error, e:
388 tb = sys.exc_info()[2]
389 if (e.errno != ENOENT and e.errno != ENOTDIR
390 and saved_exc is None):
391 saved_exc = e
392 saved_tb = tb
393 if saved_exc:
394 raise error, saved_exc, saved_tb
395 raise error, e, tb
397 # Change environ to automatically call putenv() if it exists
398 try:
399 # This will fail if there's no putenv
400 putenv
401 except NameError:
402 pass
403 else:
404 import UserDict
406 # Fake unsetenv() for Windows
407 # not sure about os2 here but
408 # I'm guessing they are the same.
410 if name in ('os2', 'nt'):
411 def unsetenv(key):
412 putenv(key, "")
414 if name == "riscos":
415 # On RISC OS, all env access goes through getenv and putenv
416 from riscosenviron import _Environ
417 elif name in ('os2', 'nt'): # Where Env Var Names Must Be UPPERCASE
418 # But we store them as upper case
419 class _Environ(UserDict.IterableUserDict):
420 def __init__(self, environ):
421 UserDict.UserDict.__init__(self)
422 data = self.data
423 for k, v in environ.items():
424 data[k.upper()] = v
425 def __setitem__(self, key, item):
426 putenv(key, item)
427 self.data[key.upper()] = item
428 def __getitem__(self, key):
429 return self.data[key.upper()]
430 try:
431 unsetenv
432 except NameError:
433 def __delitem__(self, key):
434 del self.data[key.upper()]
435 else:
436 def __delitem__(self, key):
437 unsetenv(key)
438 del self.data[key.upper()]
439 def has_key(self, key):
440 return key.upper() in self.data
441 def __contains__(self, key):
442 return key.upper() in self.data
443 def get(self, key, failobj=None):
444 return self.data.get(key.upper(), failobj)
445 def update(self, dict=None, **kwargs):
446 if dict:
447 try:
448 keys = dict.keys()
449 except AttributeError:
450 # List of (key, value)
451 for k, v in dict:
452 self[k] = v
453 else:
454 # got keys
455 # cannot use items(), since mappings
456 # may not have them.
457 for k in keys:
458 self[k] = dict[k]
459 if kwargs:
460 self.update(kwargs)
461 def copy(self):
462 return dict(self)
464 else: # Where Env Var Names Can Be Mixed Case
465 class _Environ(UserDict.IterableUserDict):
466 def __init__(self, environ):
467 UserDict.UserDict.__init__(self)
468 self.data = environ
469 def __setitem__(self, key, item):
470 putenv(key, item)
471 self.data[key] = item
472 def update(self, dict=None, **kwargs):
473 if dict:
474 try:
475 keys = dict.keys()
476 except AttributeError:
477 # List of (key, value)
478 for k, v in dict:
479 self[k] = v
480 else:
481 # got keys
482 # cannot use items(), since mappings
483 # may not have them.
484 for k in keys:
485 self[k] = dict[k]
486 if kwargs:
487 self.update(kwargs)
488 try:
489 unsetenv
490 except NameError:
491 pass
492 else:
493 def __delitem__(self, key):
494 unsetenv(key)
495 del self.data[key]
496 def copy(self):
497 return dict(self)
500 environ = _Environ(environ)
502 def getenv(key, default=None):
503 """Get an environment variable, return None if it doesn't exist.
504 The optional second argument can specify an alternate default."""
505 return environ.get(key, default)
506 __all__.append("getenv")
508 def _exists(name):
509 try:
510 eval(name)
511 return True
512 except NameError:
513 return False
515 # Supply spawn*() (probably only for Unix)
516 if _exists("fork") and not _exists("spawnv") and _exists("execv"):
518 P_WAIT = 0
519 P_NOWAIT = P_NOWAITO = 1
521 # XXX Should we support P_DETACH? I suppose it could fork()**2
522 # and close the std I/O streams. Also, P_OVERLAY is the same
523 # as execv*()?
525 def _spawnvef(mode, file, args, env, func):
526 # Internal helper; func is the exec*() function to use
527 pid = fork()
528 if not pid:
529 # Child
530 try:
531 if env is None:
532 func(file, args)
533 else:
534 func(file, args, env)
535 except:
536 _exit(127)
537 else:
538 # Parent
539 if mode == P_NOWAIT:
540 return pid # Caller is responsible for waiting!
541 while 1:
542 wpid, sts = waitpid(pid, 0)
543 if WIFSTOPPED(sts):
544 continue
545 elif WIFSIGNALED(sts):
546 return -WTERMSIG(sts)
547 elif WIFEXITED(sts):
548 return WEXITSTATUS(sts)
549 else:
550 raise error, "Not stopped, signaled or exited???"
552 def spawnv(mode, file, args):
553 """spawnv(mode, file, args) -> integer
555 Execute file with arguments from args in a subprocess.
556 If mode == P_NOWAIT return the pid of the process.
557 If mode == P_WAIT return the process's exit code if it exits normally;
558 otherwise return -SIG, where SIG is the signal that killed it. """
559 return _spawnvef(mode, file, args, None, execv)
561 def spawnve(mode, file, args, env):
562 """spawnve(mode, file, args, env) -> integer
564 Execute file with arguments from args in a subprocess with the
565 specified environment.
566 If mode == P_NOWAIT return the pid of the process.
567 If mode == P_WAIT return the process's exit code if it exits normally;
568 otherwise return -SIG, where SIG is the signal that killed it. """
569 return _spawnvef(mode, file, args, env, execve)
571 # Note: spawnvp[e] is't currently supported on Windows
573 def spawnvp(mode, file, args):
574 """spawnvp(mode, file, args) -> integer
576 Execute file (which is looked for along $PATH) with arguments from
577 args in a subprocess.
578 If mode == P_NOWAIT return the pid of the process.
579 If mode == P_WAIT return the process's exit code if it exits normally;
580 otherwise return -SIG, where SIG is the signal that killed it. """
581 return _spawnvef(mode, file, args, None, execvp)
583 def spawnvpe(mode, file, args, env):
584 """spawnvpe(mode, file, args, env) -> integer
586 Execute file (which is looked for along $PATH) with arguments from
587 args in a subprocess with the supplied environment.
588 If mode == P_NOWAIT return the pid of the process.
589 If mode == P_WAIT return the process's exit code if it exits normally;
590 otherwise return -SIG, where SIG is the signal that killed it. """
591 return _spawnvef(mode, file, args, env, execvpe)
593 if _exists("spawnv"):
594 # These aren't supplied by the basic Windows code
595 # but can be easily implemented in Python
597 def spawnl(mode, file, *args):
598 """spawnl(mode, file, *args) -> integer
600 Execute file with arguments from args in a subprocess.
601 If mode == P_NOWAIT return the pid of the process.
602 If mode == P_WAIT return the process's exit code if it exits normally;
603 otherwise return -SIG, where SIG is the signal that killed it. """
604 return spawnv(mode, file, args)
606 def spawnle(mode, file, *args):
607 """spawnle(mode, file, *args, env) -> integer
609 Execute file with arguments from args in a subprocess with the
610 supplied environment.
611 If mode == P_NOWAIT return the pid of the process.
612 If mode == P_WAIT return the process's exit code if it exits normally;
613 otherwise return -SIG, where SIG is the signal that killed it. """
614 env = args[-1]
615 return spawnve(mode, file, args[:-1], env)
618 __all__.extend(["spawnv", "spawnve", "spawnl", "spawnle",])
621 if _exists("spawnvp"):
622 # At the moment, Windows doesn't implement spawnvp[e],
623 # so it won't have spawnlp[e] either.
624 def spawnlp(mode, file, *args):
625 """spawnlp(mode, file, *args) -> integer
627 Execute file (which is looked for along $PATH) with arguments from
628 args in a subprocess with the supplied environment.
629 If mode == P_NOWAIT return the pid of the process.
630 If mode == P_WAIT return the process's exit code if it exits normally;
631 otherwise return -SIG, where SIG is the signal that killed it. """
632 return spawnvp(mode, file, args)
634 def spawnlpe(mode, file, *args):
635 """spawnlpe(mode, file, *args, env) -> integer
637 Execute file (which is looked for along $PATH) with arguments from
638 args in a subprocess with the supplied environment.
639 If mode == P_NOWAIT return the pid of the process.
640 If mode == P_WAIT return the process's exit code if it exits normally;
641 otherwise return -SIG, where SIG is the signal that killed it. """
642 env = args[-1]
643 return spawnvpe(mode, file, args[:-1], env)
646 __all__.extend(["spawnvp", "spawnvpe", "spawnlp", "spawnlpe",])
649 # Supply popen2 etc. (for Unix)
650 if _exists("fork"):
651 if not _exists("popen2"):
652 def popen2(cmd, mode="t", bufsize=-1):
653 """Execute the shell command 'cmd' in a sub-process. On UNIX, 'cmd'
654 may be a sequence, in which case arguments will be passed directly to
655 the program without shell intervention (as with os.spawnv()). If 'cmd'
656 is a string it will be passed to the shell (as with os.system()). If
657 'bufsize' is specified, it sets the buffer size for the I/O pipes. The
658 file objects (child_stdin, child_stdout) are returned."""
659 import popen2
660 stdout, stdin = popen2.popen2(cmd, bufsize)
661 return stdin, stdout
662 __all__.append("popen2")
664 if not _exists("popen3"):
665 def popen3(cmd, mode="t", bufsize=-1):
666 """Execute the shell command 'cmd' in a sub-process. On UNIX, 'cmd'
667 may be a sequence, in which case arguments will be passed directly to
668 the program without shell intervention (as with os.spawnv()). If 'cmd'
669 is a string it will be passed to the shell (as with os.system()). If
670 'bufsize' is specified, it sets the buffer size for the I/O pipes. The
671 file objects (child_stdin, child_stdout, child_stderr) are returned."""
672 import popen2
673 stdout, stdin, stderr = popen2.popen3(cmd, bufsize)
674 return stdin, stdout, stderr
675 __all__.append("popen3")
677 if not _exists("popen4"):
678 def popen4(cmd, mode="t", bufsize=-1):
679 """Execute the shell command 'cmd' in a sub-process. On UNIX, 'cmd'
680 may be a sequence, in which case arguments will be passed directly to
681 the program without shell intervention (as with os.spawnv()). If 'cmd'
682 is a string it will be passed to the shell (as with os.system()). If
683 'bufsize' is specified, it sets the buffer size for the I/O pipes. The
684 file objects (child_stdin, child_stdout_stderr) are returned."""
685 import popen2
686 stdout, stdin = popen2.popen4(cmd, bufsize)
687 return stdin, stdout
688 __all__.append("popen4")
690 import copy_reg as _copy_reg
692 def _make_stat_result(tup, dict):
693 return stat_result(tup, dict)
695 def _pickle_stat_result(sr):
696 (type, args) = sr.__reduce__()
697 return (_make_stat_result, args)
699 try:
700 _copy_reg.pickle(stat_result, _pickle_stat_result, _make_stat_result)
701 except NameError: # stat_result may not exist
702 pass
704 def _make_statvfs_result(tup, dict):
705 return statvfs_result(tup, dict)
707 def _pickle_statvfs_result(sr):
708 (type, args) = sr.__reduce__()
709 return (_make_statvfs_result, args)
711 try:
712 _copy_reg.pickle(statvfs_result, _pickle_statvfs_result,
713 _make_statvfs_result)
714 except NameError: # statvfs_result may not exist
715 pass
717 if not _exists("urandom"):
718 def urandom(n):
719 """urandom(n) -> str
721 Return a string of n random bytes suitable for cryptographic use.
724 try:
725 _urandomfd = open("/dev/urandom", O_RDONLY)
726 except:
727 raise NotImplementedError("/dev/urandom (or equivalent) not found")
728 bytes = ""
729 while len(bytes) < n:
730 bytes += read(_urandomfd, n - len(bytes))
731 close(_urandomfd)
732 return bytes