os

1 r"""OS routines for NT or Posix depending on what system we're on. 2 3 This exports: 4 - all functions from posix, nt, os2, or ce, e.g. unlink, stat, etc. 5 - os.path is one of the modules posixpath, or ntpath 6 - os.name is 'posix', 'nt', 'os2', '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.) 16 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 """ 23 24 #' 25 26 import sys, errno 27 28 _names = sys.builtin_module_names 29 30 # Note: more names are added to __all__ later. 31 __all__ = ["altsep", "curdir", "pardir", "sep", "extsep", "pathsep", "linesep", 32 "defpath", "name", "path", "devnull", 33 "SEEK_SET", "SEEK_CUR", "SEEK_END"] 34

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] != '_']

40 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 50 51 import posix 52 __all__.extend(_get_exports_list(posix)) 53 del posix 54 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 64 65 import nt 66 __all__.extend(_get_exports_list(nt)) 67 del nt 68 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 82 83 import os2 84 __all__.extend(_get_exports_list(os2)) 85 del os2 86 87 elif 'ce' in _names: 88 name = 'ce' 89 linesep = '\r\n' 90 from ce import * 91 try: 92 from ce import _exit 93 except ImportError: 94 pass 95 # We can use the standard Windows path. 96 import ntpath as path 97 98 import ce 99 __all__.extend(_get_exports_list(ce)) 100 del ce 101 102 elif 'riscos' in _names: 103 name = 'riscos' 104 linesep = '\n' 105 from riscos import * 106 try: 107 from riscos import _exit 108 except ImportError: 109 pass 110 import riscospath as path 111 112 import riscos 113 __all__.extend(_get_exports_list(riscos)) 114 del riscos 115 116 else: 117 raise ImportError, 'no os specific module found' 118 119 sys.modules['os.path'] = path 120 from os.path import (curdir, pardir, sep, pathsep, defpath, extsep, altsep, 121 devnull) 122 123 del _names 124 125 # Python uses fixed values for the SEEK_ constants; they are mapped 126 # to native constants if necessary in posixmodule.c 127 SEEK_SET = 0 128 SEEK_CUR = 1 129 SEEK_END = 2 130 131 #' 132 133 # Super directory utilities. 134 # (Inspired by Eric Raymond; the doc strings are mostly his) 135

136 -def makedirs(name, mode=0777):

137 """makedirs(path [, mode=0777]) 138 139 Super-mkdir; create a leaf directory and all intermediate ones. 140 Works like mkdir, except that any intermediate path segment (not 141 just the rightmost) will be created if it does not exist. This is 142 recursive. 143 144 """ 145 head, tail = path.split(name) 146 if not tail: 147 head, tail = path.split(head) 148 if head and tail and not path.exists(head): 149 try: 150 makedirs(head, mode) 151 except OSError, e: 152 # be happy if someone already created the path 153 if e.errno != errno.EEXIST: 154 raise 155 if tail == curdir: # xxx/newdir/. exists if xxx/newdir exists 156 return 157 mkdir(name, mode)

158

159 -def removedirs(name):

160 """removedirs(path) 161 162 Super-rmdir; remove a leaf directory and all empty intermediate 163 ones. Works like rmdir except that, if the leaf directory is 164 successfully removed, directories corresponding to rightmost path 165 segments will be pruned away until either the whole path is 166 consumed or an error occurs. Errors during this latter phase are 167 ignored -- they generally mean that a directory was not empty. 168 169 """ 170 rmdir(name) 171 head, tail = path.split(name) 172 if not tail: 173 head, tail = path.split(head) 174 while head and tail: 175 try: 176 rmdir(head) 177 except error: 178 break 179 head, tail = path.split(head)

180

181 -def renames(old, new):

182 """renames(old, new) 183 184 Super-rename; create directories as necessary and delete any left 185 empty. Works like rename, except creation of any intermediate 186 directories needed to make the new pathname good is attempted 187 first. After the rename, directories corresponding to rightmost 188 path segments of the old name will be pruned until either the 189 whole path is consumed or a nonempty directory is found. 190 191 Note: this function can fail with the new directory structure made 192 if you lack permissions needed to unlink the leaf directory or 193 file. 194 195 """ 196 head, tail = path.split(new) 197 if head and tail and not path.exists(head): 198 makedirs(head) 199 rename(old, new) 200 head, tail = path.split(old) 201 if head and tail: 202 try: 203 removedirs(head) 204 except error: 205 pass

206 207 __all__.extend(["makedirs", "removedirs", "renames"]) 208

209 -def walk(top, topdown=True, onerror=None, followlinks=False):

210 """Directory tree generator. 211 212 For each directory in the directory tree rooted at top (including top 213 itself, but excluding '.' and '..'), yields a 3-tuple 214 215 dirpath, dirnames, filenames 216 217 dirpath is a string, the path to the directory. dirnames is a list of 218 the names of the subdirectories in dirpath (excluding '.' and '..'). 219 filenames is a list of the names of the non-directory files in dirpath. 220 Note that the names in the lists are just names, with no path components. 221 To get a full path (which begins with top) to a file or directory in 222 dirpath, do os.path.join(dirpath, name). 223 224 If optional arg 'topdown' is true or not specified, the triple for a 225 directory is generated before the triples for any of its subdirectories 226 (directories are generated top down). If topdown is false, the triple 227 for a directory is generated after the triples for all of its 228 subdirectories (directories are generated bottom up). 229 230 When topdown is true, the caller can modify the dirnames list in-place 231 (e.g., via del or slice assignment), and walk will only recurse into the 232 subdirectories whose names remain in dirnames; this can be used to prune the 233 search, or to impose a specific order of visiting. Modifying dirnames when 234 topdown is false is ineffective, since the directories in dirnames have 235 already been generated by the time dirnames itself is generated. No matter 236 the value of topdown, the list of subdirectories is retrieved before the 237 tuples for the directory and its subdirectories are generated. 238 239 By default errors from the os.listdir() call are ignored. If 240 optional arg 'onerror' is specified, it should be a function; it 241 will be called with one argument, an os.error instance. It can 242 report the error to continue with the walk, or raise the exception 243 to abort the walk. Note that the filename is available as the 244 filename attribute of the exception object. 245 246 By default, os.walk does not follow symbolic links to subdirectories on 247 systems that support them. In order to get this functionality, set the 248 optional argument 'followlinks' to true. 249 250 Caution: if you pass a relative pathname for top, don't change the 251 current working directory between resumptions of walk. walk never 252 changes the current directory, and assumes that the client doesn't 253 either. 254 255 Example: 256 257 import os 258 from os.path import join, getsize 259 for root, dirs, files in os.walk('python/Lib/email'): 260 print root, "consumes", 261 print sum([getsize(join(root, name)) for name in files]), 262 print "bytes in", len(files), "non-directory files" 263 if 'CVS' in dirs: 264 dirs.remove('CVS') # don't visit CVS directories 265 266 """ 267 268 islink, join, isdir = path.islink, path.join, path.isdir 269 270 # We may not have read permission for top, in which case we can't 271 # get a list of the files the directory contains. os.path.walk 272 # always suppressed the exception then, rather than blow up for a 273 # minor reason when (say) a thousand readable directories are still 274 # left to visit. That logic is copied here. 275 try: 276 # Note that listdir and error are globals in this module due 277 # to earlier import-*. 278 names = listdir(top) 279 except error, err: 280 if onerror is not None: 281 onerror(err) 282 return 283 284 dirs, nondirs = [], [] 285 for name in names: 286 if isdir(join(top, name)): 287 dirs.append(name) 288 else: 289 nondirs.append(name) 290 291 if topdown: 292 yield top, dirs, nondirs 293 for name in dirs: 294 new_path = join(top, name) 295 if followlinks or not islink(new_path): 296 for x in walk(new_path, topdown, onerror, followlinks): 297 yield x 298 if not topdown: 299 yield top, dirs, nondirs

300 301 __all__.append("walk") 302 303 # Make sure os.environ exists, at least 304 try: 305 environ 306 except NameError: 307 environ = {} 308

309 -def execl(file, *args):

310 """execl(file, *args) 311 312 Execute the executable file with argument list args, replacing the 313 current process. """ 314 execv(file, args)

315

316 -def execle(file, *args):

317 """execle(file, *args, env) 318 319 Execute the executable file with argument list args and 320 environment env, replacing the current process. """ 321 env = args[-1] 322 execve(file, args[:-1], env)

323

324 -def execlp(file, *args):

325 """execlp(file, *args) 326 327 Execute the executable file (which is searched for along $PATH) 328 with argument list args, replacing the current process. """ 329 execvp(file, args)

330

331 -def execlpe(file, *args):

332 """execlpe(file, *args, env) 333 334 Execute the executable file (which is searched for along $PATH) 335 with argument list args and environment env, replacing the current 336 process. """ 337 env = args[-1] 338 execvpe(file, args[:-1], env)

339

340 -def execvp(file, args):

341 """execvp(file, args) 342 343 Execute the executable file (which is searched for along $PATH) 344 with argument list args, replacing the current process. 345 args may be a list or tuple of strings. """ 346 _execvpe(file, args)

347

348 -def execvpe(file, args, env):

349 """execvpe(file, args, env) 350 351 Execute the executable file (which is searched for along $PATH) 352 with argument list args and environment env , replacing the 353 current process. 354 args may be a list or tuple of strings. """ 355 _execvpe(file, args, env)

356 357 __all__.extend(["execl","execle","execlp","execlpe","execvp","execvpe"]) 358

359 -def _execvpe(file, args, env=None):

360 if env is not None: 361 func = execve 362 argrest = (args, env) 363 else: 364 func = execv 365 argrest = (args,) 366 env = environ 367 368 head, tail = path.split(file) 369 if head: 370 func(file, *argrest) 371 return 372 if 'PATH' in env: 373 envpath = env['PATH'] 374 else: 375 envpath = defpath 376 PATH = envpath.split(pathsep) 377 saved_exc = None 378 saved_tb = None 379 for dir in PATH: 380 fullname = path.join(dir, file) 381 try: 382 func(fullname, *argrest) 383 except error, e: 384 tb = sys.exc_info()[2] 385 if (e.errno != errno.ENOENT and e.errno != errno.ENOTDIR 386 and saved_exc is None): 387 saved_exc = e 388 saved_tb = tb 389 if saved_exc: 390 raise error, saved_exc, saved_tb 391 raise error, e, tb

392 393 # Change environ to automatically call putenv() if it exists 394 try: 395 # This will fail if there's no putenv 396 putenv 397 except NameError: 398 pass 399 else: 400 import UserDict 401 402 # Fake unsetenv() for Windows 403 # not sure about os2 here but 404 # I'm guessing they are the same. 405 406 if name in ('os2', 'nt'):

407 - def unsetenv(key):

408 putenv(key, "")

409 410 if name == "riscos": 411 # On RISC OS, all env access goes through getenv and putenv 412 from riscosenviron import _Environ 413 elif name in ('os2', 'nt'): # Where Env Var Names Must Be UPPERCASE 414 # But we store them as upper case

415 - class _Environ(UserDict.IterableUserDict):

416 - def __init__(self, environ):

417 UserDict.UserDict.__init__(self) 418 data = self.data 419 for k, v in environ.items(): 420 data[k.upper()] = v

421 - def __setitem__(self, key, item):

422 putenv(key, item) 423 self.data[key.upper()] = item

424 - def __getitem__(self, key):

425 return self.data[key.upper()]

426 try: 427 unsetenv 428 except NameError:

429 - def __delitem__(self, key):

430 del self.data[key.upper()]

431 else:

432 - def __delitem__(self, key):

433 unsetenv(key) 434 del self.data[key.upper()]

435 - def clear(self):

436 for key in self.data.keys(): 437 unsetenv(key) 438 del self.data[key]

439 - def pop(self, key, *args):

440 unsetenv(key) 441 return self.data.pop(key.upper(), *args)

442 - def has_key(self, key):

443 return key.upper() in self.data

444 - def __contains__(self, key):

445 return key.upper() in self.data

446 - def get(self, key, failobj=None):

447 return self.data.get(key.upper(), failobj)

448 - def update(self, dict=None, **kwargs):

449 if dict: 450 try: 451 keys = dict.keys() 452 except AttributeError: 453 # List of (key, value) 454 for k, v in dict: 455 self[k] = v 456 else: 457 # got keys 458 # cannot use items(), since mappings 459 # may not have them. 460 for k in keys: 461 self[k] = dict[k] 462 if kwargs: 463 self.update(kwargs)

464 - def copy(self):

465 return dict(self)

466 467 else: # Where Env Var Names Can Be Mixed Case

468 - class _Environ(UserDict.IterableUserDict):

469 - def __init__(self, environ):

470 UserDict.UserDict.__init__(self) 471 self.data = environ

472 - def __setitem__(self, key, item):

473 putenv(key, item) 474 self.data[key] = item

475 - def update(self, dict=None, **kwargs):

476 if dict: 477 try: 478 keys = dict.keys() 479 except AttributeError: 480 # List of (key, value) 481 for k, v in dict: 482 self[k] = v 483 else: 484 # got keys 485 # cannot use items(), since mappings 486 # may not have them. 487 for k in keys: 488 self[k] = dict[k] 489 if kwargs: 490 self.update(kwargs)

491 try: 492 unsetenv 493 except NameError: 494 pass 495 else:

496 - def __delitem__(self, key):

497 unsetenv(key) 498 del self.data[key]

499 - def clear(self):

500 for key in self.data.keys(): 501 unsetenv(key) 502 del self.data[key]

503 - def pop(self, key, *args):

504 unsetenv(key) 505 return self.data.pop(key, *args)

506 - def copy(self):

507 return dict(self)

508 509 510 environ = _Environ(environ) 511

512 -def getenv(key, default=None):

513 """Get an environment variable, return None if it doesn't exist. 514 The optional second argument can specify an alternate default.""" 515 return environ.get(key, default)

516 __all__.append("getenv") 517

518 -def _exists(name):

519 return name in globals()

520 521 # Supply spawn*() (probably only for Unix) 522 if _exists("fork") and not _exists("spawnv") and _exists("execv"): 523 524 P_WAIT = 0 525 P_NOWAIT = P_NOWAITO = 1 526 527 # XXX Should we support P_DETACH? I suppose it could fork()**2 528 # and close the std I/O streams. Also, P_OVERLAY is the same 529 # as execv*()? 530

531 - def _spawnvef(mode, file, args, env, func):

532 # Internal helper; func is the exec*() function to use 533 pid = fork() 534 if not pid: 535 # Child 536 try: 537 if env is None: 538 func(file, args) 539 else: 540 func(file, args, env) 541 except: 542 _exit(127) 543 else: 544 # Parent 545 if mode == P_NOWAIT: 546 return pid # Caller is responsible for waiting! 547 while 1: 548 wpid, sts = waitpid(pid, 0) 549 if WIFSTOPPED(sts): 550 continue 551 elif WIFSIGNALED(sts): 552 return -WTERMSIG(sts) 553 elif WIFEXITED(sts): 554 return WEXITSTATUS(sts) 555 else: 556 raise error, "Not stopped, signaled or exited???"

557

558 - def spawnv(mode, file, args):

559 """spawnv(mode, file, args) -> integer 560 561 Execute file with arguments from args in a subprocess. 562 If mode == P_NOWAIT return the pid of the process. 563 If mode == P_WAIT return the process's exit code if it exits normally; 564 otherwise return -SIG, where SIG is the signal that killed it. """ 565 return _spawnvef(mode, file, args, None, execv)

566

567 - def spawnve(mode, file, args, env):

568 """spawnve(mode, file, args, env) -> integer 569 570 Execute file with arguments from args in a subprocess with the 571 specified environment. 572 If mode == P_NOWAIT return the pid of the process. 573 If mode == P_WAIT return the process's exit code if it exits normally; 574 otherwise return -SIG, where SIG is the signal that killed it. """ 575 return _spawnvef(mode, file, args, env, execve)

576 577 # Note: spawnvp[e] is't currently supported on Windows 578

579 - def spawnvp(mode, file, args):

580 """spawnvp(mode, file, args) -> integer 581 582 Execute file (which is looked for along $PATH) with arguments from 583 args in a subprocess. 584 If mode == P_NOWAIT return the pid of the process. 585 If mode == P_WAIT return the process's exit code if it exits normally; 586 otherwise return -SIG, where SIG is the signal that killed it. """ 587 return _spawnvef(mode, file, args, None, execvp)

588

589 - def spawnvpe(mode, file, args, env):

590 """spawnvpe(mode, file, args, env) -> integer 591 592 Execute file (which is looked for along $PATH) with arguments from 593 args in a subprocess with the supplied environment. 594 If mode == P_NOWAIT return the pid of the process. 595 If mode == P_WAIT return the process's exit code if it exits normally; 596 otherwise return -SIG, where SIG is the signal that killed it. """ 597 return _spawnvef(mode, file, args, env, execvpe)

598 599 if _exists("spawnv"): 600 # These aren't supplied by the basic Windows code 601 # but can be easily implemented in Python 602

603 - def spawnl(mode, file, *args):

604 """spawnl(mode, file, *args) -> integer 605 606 Execute file with arguments from args in a subprocess. 607 If mode == P_NOWAIT return the pid of the process. 608 If mode == P_WAIT return the process's exit code if it exits normally; 609 otherwise return -SIG, where SIG is the signal that killed it. """ 610 return spawnv(mode, file, args)

611

612 - def spawnle(mode, file, *args):

613 """spawnle(mode, file, *args, env) -> integer 614 615 Execute file with arguments from args in a subprocess with the 616 supplied environment. 617 If mode == P_NOWAIT return the pid of the process. 618 If mode == P_WAIT return the process's exit code if it exits normally; 619 otherwise return -SIG, where SIG is the signal that killed it. """ 620 env = args[-1] 621 return spawnve(mode, file, args[:-1], env)

622 623 624 __all__.extend(["spawnv", "spawnve", "spawnl", "spawnle",]) 625 626 627 if _exists("spawnvp"): 628 # At the moment, Windows doesn't implement spawnvp[e], 629 # so it won't have spawnlp[e] either.

630 - def spawnlp(mode, file, *args):

631 """spawnlp(mode, file, *args) -> integer 632 633 Execute file (which is looked for along $PATH) with arguments from 634 args in a subprocess with the supplied environment. 635 If mode == P_NOWAIT return the pid of the process. 636 If mode == P_WAIT return the process's exit code if it exits normally; 637 otherwise return -SIG, where SIG is the signal that killed it. """ 638 return spawnvp(mode, file, args)

639

640 - def spawnlpe(mode, file, *args):

641 """spawnlpe(mode, file, *args, env) -> integer 642 643 Execute file (which is looked for along $PATH) with arguments from 644 args in a subprocess with the supplied environment. 645 If mode == P_NOWAIT return the pid of the process. 646 If mode == P_WAIT return the process's exit code if it exits normally; 647 otherwise return -SIG, where SIG is the signal that killed it. """ 648 env = args[-1] 649 return spawnvpe(mode, file, args[:-1], env)

650 651 652 __all__.extend(["spawnvp", "spawnvpe", "spawnlp", "spawnlpe",]) 653 654 655 # Supply popen2 etc. (for Unix) 656 if _exists("fork"): 657 if not _exists("popen2"):

658 - def popen2(cmd, mode="t", bufsize=-1):

659 """Execute the shell command 'cmd' in a sub-process. On UNIX, 'cmd' 660 may be a sequence, in which case arguments will be passed directly to 661 the program without shell intervention (as with os.spawnv()). If 'cmd' 662 is a string it will be passed to the shell (as with os.system()). If 663 'bufsize' is specified, it sets the buffer size for the I/O pipes. The 664 file objects (child_stdin, child_stdout) are returned.""" 665 import warnings 666 msg = "os.popen2 is deprecated. Use the subprocess module." 667 warnings.warn(msg, DeprecationWarning, stacklevel=2) 668 669 import subprocess 670 PIPE = subprocess.PIPE 671 p = subprocess.Popen(cmd, shell=isinstance(cmd, basestring), 672 bufsize=bufsize, stdin=PIPE, stdout=PIPE, 673 close_fds=True) 674 return p.stdin, p.stdout

675 __all__.append("popen2") 676 677 if not _exists("popen3"):

678 - def popen3(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, child_stderr) are returned.""" 685 import warnings 686 msg = "os.popen3 is deprecated. Use the subprocess module." 687 warnings.warn(msg, DeprecationWarning, stacklevel=2) 688 689 import subprocess 690 PIPE = subprocess.PIPE 691 p = subprocess.Popen(cmd, shell=isinstance(cmd, basestring), 692 bufsize=bufsize, stdin=PIPE, stdout=PIPE, 693 stderr=PIPE, close_fds=True) 694 return p.stdin, p.stdout, p.stderr

695 __all__.append("popen3") 696 697 if not _exists("popen4"):

698 - def popen4(cmd, mode="t", bufsize=-1):

699 """Execute the shell command 'cmd' in a sub-process. On UNIX, 'cmd' 700 may be a sequence, in which case arguments will be passed directly to 701 the program without shell intervention (as with os.spawnv()). If 'cmd' 702 is a string it will be passed to the shell (as with os.system()). If 703 'bufsize' is specified, it sets the buffer size for the I/O pipes. The 704 file objects (child_stdin, child_stdout_stderr) are returned.""" 705 import warnings 706 msg = "os.popen4 is deprecated. Use the subprocess module." 707 warnings.warn(msg, DeprecationWarning, stacklevel=2) 708 709 import subprocess 710 PIPE = subprocess.PIPE 711 p = subprocess.Popen(cmd, shell=isinstance(cmd, basestring), 712 bufsize=bufsize, stdin=PIPE, stdout=PIPE, 713 stderr=subprocess.STDOUT, close_fds=True) 714 return p.stdin, p.stdout

715 __all__.append("popen4") 716 717 import copy_reg as _copy_reg 718

719 -def _make_stat_result(tup, dict):

720 return stat_result(tup, dict)

721

722 -def _pickle_stat_result(sr):

723 (type, args) = sr.__reduce__() 724 return (_make_stat_result, args)

725 726 try: 727 _copy_reg.pickle(stat_result, _pickle_stat_result, _make_stat_result) 728 except NameError: # stat_result may not exist 729 pass 730

731 -def _make_statvfs_result(tup, dict):

732 return statvfs_result(tup, dict)

733

734 -def _pickle_statvfs_result(sr):

735 (type, args) = sr.__reduce__() 736 return (_make_statvfs_result, args)

737 738 try: 739 _copy_reg.pickle(statvfs_result, _pickle_statvfs_result, 740 _make_statvfs_result) 741 except NameError: # statvfs_result may not exist 742 pass 743

Source Code for Module os