os

1 r"""OS routines for Mac, 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 way 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 233 the search, or to impose a specific order of visiting. Modifying 234 dirnames when topdown is false is ineffective, since the directories in 235 dirnames have already been generated by the time dirnames itself is 236 generated. 237 238 By default errors from the os.listdir() call are ignored. If 239 optional arg 'onerror' is specified, it should be a function; it 240 will be called with one argument, an os.error instance. It can 241 report the error to continue with the walk, or raise the exception 242 to abort the walk. Note that the filename is available as the 243 filename attribute of the exception object. 244 245 By default, os.walk does not follow symbolic links to subdirectories on 246 systems that support them. In order to get this functionality, set the 247 optional argument 'followlinks' to true. 248 249 Caution: if you pass a relative pathname for top, don't change the 250 current working directory between resumptions of walk. walk never 251 changes the current directory, and assumes that the client doesn't 252 either. 253 254 Example: 255 256 import os 257 from os.path import join, getsize 258 for root, dirs, files in os.walk('python/Lib/email'): 259 print root, "consumes", 260 print sum([getsize(join(root, name)) for name in files]), 261 print "bytes in", len(files), "non-directory files" 262 if 'CVS' in dirs: 263 dirs.remove('CVS') # don't visit CVS directories 264 """ 265 266 islink, join, isdir = path.islink, path.join, path.isdir 267 268 # We may not have read permission for top, in which case we can't 269 # get a list of the files the directory contains. os.path.walk 270 # always suppressed the exception then, rather than blow up for a 271 # minor reason when (say) a thousand readable directories are still 272 # left to visit. That logic is copied here. 273 try: 274 # Note that listdir and error are globals in this module due 275 # to earlier import-*. 276 names = listdir(top) 277 except error, err: 278 if onerror is not None: 279 onerror(err) 280 return 281 282 dirs, nondirs = [], [] 283 for name in names: 284 if isdir(join(top, name)): 285 dirs.append(name) 286 else: 287 nondirs.append(name) 288 289 if topdown: 290 yield top, dirs, nondirs 291 for name in dirs: 292 new_path = join(top, name) 293 if followlinks or not islink(new_path): 294 for x in walk(new_path, topdown, onerror, followlinks): 295 yield x 296 if not topdown: 297 yield top, dirs, nondirs

298 299 __all__.append("walk") 300 301 # Make sure os.environ exists, at least 302 try: 303 environ 304 except NameError: 305 environ = {} 306

307 -def execl(file, *args):

308 """execl(file, *args) 309 310 Execute the executable file with argument list args, replacing the 311 current process. """ 312 execv(file, args)

313

314 -def execle(file, *args):

315 """execle(file, *args, env) 316 317 Execute the executable file with argument list args and 318 environment env, replacing the current process. """ 319 env = args[-1] 320 execve(file, args[:-1], env)

321

322 -def execlp(file, *args):

323 """execlp(file, *args) 324 325 Execute the executable file (which is searched for along $PATH) 326 with argument list args, replacing the current process. """ 327 execvp(file, args)

328

329 -def execlpe(file, *args):

330 """execlpe(file, *args, env) 331 332 Execute the executable file (which is searched for along $PATH) 333 with argument list args and environment env, replacing the current 334 process. """ 335 env = args[-1] 336 execvpe(file, args[:-1], env)

337

338 -def execvp(file, args):

339 """execvp(file, args) 340 341 Execute the executable file (which is searched for along $PATH) 342 with argument list args, replacing the current process. 343 args may be a list or tuple of strings. """ 344 _execvpe(file, args)

345

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

347 """execvpe(file, args, env) 348 349 Execute the executable file (which is searched for along $PATH) 350 with argument list args and environment env , replacing the 351 current process. 352 args may be a list or tuple of strings. """ 353 _execvpe(file, args, env)

354 355 __all__.extend(["execl","execle","execlp","execlpe","execvp","execvpe"]) 356

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

358 if env is not None: 359 func = execve 360 argrest = (args, env) 361 else: 362 func = execv 363 argrest = (args,) 364 env = environ 365 366 head, tail = path.split(file) 367 if head: 368 func(file, *argrest) 369 return 370 if 'PATH' in env: 371 envpath = env['PATH'] 372 else: 373 envpath = defpath 374 PATH = envpath.split(pathsep) 375 saved_exc = None 376 saved_tb = None 377 for dir in PATH: 378 fullname = path.join(dir, file) 379 try: 380 func(fullname, *argrest) 381 except error, e: 382 tb = sys.exc_info()[2] 383 if (e.errno != errno.ENOENT and e.errno != errno.ENOTDIR 384 and saved_exc is None): 385 saved_exc = e 386 saved_tb = tb 387 if saved_exc: 388 raise error, saved_exc, saved_tb 389 raise error, e, tb

390 391 # Change environ to automatically call putenv() if it exists 392 try: 393 # This will fail if there's no putenv 394 putenv 395 except NameError: 396 pass 397 else: 398 import UserDict 399 400 # Fake unsetenv() for Windows 401 # not sure about os2 here but 402 # I'm guessing they are the same. 403 404 if name in ('os2', 'nt'):

405 - def unsetenv(key):

406 putenv(key, "")

407 408 if name == "riscos": 409 # On RISC OS, all env access goes through getenv and putenv 410 from riscosenviron import _Environ 411 elif name in ('os2', 'nt'): # Where Env Var Names Must Be UPPERCASE 412 # But we store them as upper case

413 - class _Environ(UserDict.IterableUserDict):

414 - def __init__(self, environ):

415 UserDict.UserDict.__init__(self) 416 data = self.data 417 for k, v in environ.items(): 418 data[k.upper()] = v

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

420 putenv(key, item) 421 self.data[key.upper()] = item

422 - def __getitem__(self, key):

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

424 try: 425 unsetenv 426 except NameError:

427 - def __delitem__(self, key):

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

429 else:

430 - def __delitem__(self, key):

431 unsetenv(key) 432 del self.data[key.upper()]

433 - def clear(self):

434 for key in self.data.keys(): 435 unsetenv(key) 436 del self.data[key]

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

438 unsetenv(key) 439 return self.data.pop(key.upper(), *args)

440 - def has_key(self, key):

441 return key.upper() in self.data

442 - def __contains__(self, key):

443 return key.upper() in self.data

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

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

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

447 if dict: 448 try: 449 keys = dict.keys() 450 except AttributeError: 451 # List of (key, value) 452 for k, v in dict: 453 self[k] = v 454 else: 455 # got keys 456 # cannot use items(), since mappings 457 # may not have them. 458 for k in keys: 459 self[k] = dict[k] 460 if kwargs: 461 self.update(kwargs)

462 - def copy(self):

463 return dict(self)

464 465 else: # Where Env Var Names Can Be Mixed Case

466 - class _Environ(UserDict.IterableUserDict):

467 - def __init__(self, environ):

468 UserDict.UserDict.__init__(self) 469 self.data = environ

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

471 putenv(key, item) 472 self.data[key] = item

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

474 if dict: 475 try: 476 keys = dict.keys() 477 except AttributeError: 478 # List of (key, value) 479 for k, v in dict: 480 self[k] = v 481 else: 482 # got keys 483 # cannot use items(), since mappings 484 # may not have them. 485 for k in keys: 486 self[k] = dict[k] 487 if kwargs: 488 self.update(kwargs)

489 try: 490 unsetenv 491 except NameError: 492 pass 493 else:

494 - def __delitem__(self, key):

495 unsetenv(key) 496 del self.data[key]

497 - def clear(self):

498 for key in self.data.keys(): 499 unsetenv(key) 500 del self.data[key]

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

502 unsetenv(key) 503 return self.data.pop(key, *args)

504 - def copy(self):

505 return dict(self)

506 507 508 environ = _Environ(environ) 509

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

511 """Get an environment variable, return None if it doesn't exist. 512 The optional second argument can specify an alternate default.""" 513 return environ.get(key, default)

514 __all__.append("getenv") 515

516 -def _exists(name):

517 return name in globals()

518 519 # Supply spawn*() (probably only for Unix) 520 if _exists("fork") and not _exists("spawnv") and _exists("execv"): 521 522 P_WAIT = 0 523 P_NOWAIT = P_NOWAITO = 1 524 525 # XXX Should we support P_DETACH? I suppose it could fork()**2 526 # and close the std I/O streams. Also, P_OVERLAY is the same 527 # as execv*()? 528

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

530 # Internal helper; func is the exec*() function to use 531 pid = fork() 532 if not pid: 533 # Child 534 try: 535 if env is None: 536 func(file, args) 537 else: 538 func(file, args, env) 539 except: 540 _exit(127) 541 else: 542 # Parent 543 if mode == P_NOWAIT: 544 return pid # Caller is responsible for waiting! 545 while 1: 546 wpid, sts = waitpid(pid, 0) 547 if WIFSTOPPED(sts): 548 continue 549 elif WIFSIGNALED(sts): 550 return -WTERMSIG(sts) 551 elif WIFEXITED(sts): 552 return WEXITSTATUS(sts) 553 else: 554 raise error, "Not stopped, signaled or exited???"

555

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

557 """spawnv(mode, file, args) -> integer 558 559 Execute file with arguments from args in a subprocess. 560 If mode == P_NOWAIT return the pid of the process. 561 If mode == P_WAIT return the process's exit code if it exits normally; 562 otherwise return -SIG, where SIG is the signal that killed it. """ 563 return _spawnvef(mode, file, args, None, execv)

564

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

566 """spawnve(mode, file, args, env) -> integer 567 568 Execute file with arguments from args in a subprocess with the 569 specified environment. 570 If mode == P_NOWAIT return the pid of the process. 571 If mode == P_WAIT return the process's exit code if it exits normally; 572 otherwise return -SIG, where SIG is the signal that killed it. """ 573 return _spawnvef(mode, file, args, env, execve)

574 575 # Note: spawnvp[e] is't currently supported on Windows 576

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

578 """spawnvp(mode, file, args) -> integer 579 580 Execute file (which is looked for along $PATH) with arguments from 581 args in a subprocess. 582 If mode == P_NOWAIT return the pid of the process. 583 If mode == P_WAIT return the process's exit code if it exits normally; 584 otherwise return -SIG, where SIG is the signal that killed it. """ 585 return _spawnvef(mode, file, args, None, execvp)

586

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

588 """spawnvpe(mode, file, args, env) -> integer 589 590 Execute file (which is looked for along $PATH) with arguments from 591 args in a subprocess with the supplied environment. 592 If mode == P_NOWAIT return the pid of the process. 593 If mode == P_WAIT return the process's exit code if it exits normally; 594 otherwise return -SIG, where SIG is the signal that killed it. """ 595 return _spawnvef(mode, file, args, env, execvpe)

596 597 if _exists("spawnv"): 598 # These aren't supplied by the basic Windows code 599 # but can be easily implemented in Python 600

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

602 """spawnl(mode, file, *args) -> integer 603 604 Execute file with arguments from args in a subprocess. 605 If mode == P_NOWAIT return the pid of the process. 606 If mode == P_WAIT return the process's exit code if it exits normally; 607 otherwise return -SIG, where SIG is the signal that killed it. """ 608 return spawnv(mode, file, args)

609

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

611 """spawnle(mode, file, *args, env) -> integer 612 613 Execute file with arguments from args in a subprocess with the 614 supplied environment. 615 If mode == P_NOWAIT return the pid of the process. 616 If mode == P_WAIT return the process's exit code if it exits normally; 617 otherwise return -SIG, where SIG is the signal that killed it. """ 618 env = args[-1] 619 return spawnve(mode, file, args[:-1], env)

620 621 622 __all__.extend(["spawnv", "spawnve", "spawnl", "spawnle",]) 623 624 625 if _exists("spawnvp"): 626 # At the moment, Windows doesn't implement spawnvp[e], 627 # so it won't have spawnlp[e] either.

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

629 """spawnlp(mode, file, *args) -> integer 630 631 Execute file (which is looked for along $PATH) with arguments from 632 args in a subprocess with the supplied environment. 633 If mode == P_NOWAIT return the pid of the process. 634 If mode == P_WAIT return the process's exit code if it exits normally; 635 otherwise return -SIG, where SIG is the signal that killed it. """ 636 return spawnvp(mode, file, args)

637

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

639 """spawnlpe(mode, file, *args, env) -> integer 640 641 Execute file (which is looked for along $PATH) with arguments from 642 args in a subprocess with the supplied environment. 643 If mode == P_NOWAIT return the pid of the process. 644 If mode == P_WAIT return the process's exit code if it exits normally; 645 otherwise return -SIG, where SIG is the signal that killed it. """ 646 env = args[-1] 647 return spawnvpe(mode, file, args[:-1], env)

648 649 650 __all__.extend(["spawnvp", "spawnvpe", "spawnlp", "spawnlpe",]) 651 652 653 # Supply popen2 etc. (for Unix) 654 if _exists("fork"): 655 if not _exists("popen2"):

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

657 """Execute the shell command 'cmd' in a sub-process. On UNIX, 'cmd' 658 may be a sequence, in which case arguments will be passed directly to 659 the program without shell intervention (as with os.spawnv()). If 'cmd' 660 is a string it will be passed to the shell (as with os.system()). If 661 'bufsize' is specified, it sets the buffer size for the I/O pipes. The 662 file objects (child_stdin, child_stdout) are returned.""" 663 import warnings 664 msg = "os.popen2 is deprecated. Use the subprocess module." 665 warnings.warn(msg, DeprecationWarning, stacklevel=2) 666 667 import subprocess 668 PIPE = subprocess.PIPE 669 p = subprocess.Popen(cmd, shell=isinstance(cmd, basestring), 670 bufsize=bufsize, stdin=PIPE, stdout=PIPE, 671 close_fds=True) 672 return p.stdin, p.stdout

673 __all__.append("popen2") 674 675 if not _exists("popen3"):

676 - def popen3(cmd, mode="t", bufsize=-1):

677 """Execute the shell command 'cmd' in a sub-process. On UNIX, 'cmd' 678 may be a sequence, in which case arguments will be passed directly to 679 the program without shell intervention (as with os.spawnv()). If 'cmd' 680 is a string it will be passed to the shell (as with os.system()). If 681 'bufsize' is specified, it sets the buffer size for the I/O pipes. The 682 file objects (child_stdin, child_stdout, child_stderr) are returned.""" 683 import warnings 684 msg = "os.popen3 is deprecated. Use the subprocess module." 685 warnings.warn(msg, DeprecationWarning, stacklevel=2) 686 687 import subprocess 688 PIPE = subprocess.PIPE 689 p = subprocess.Popen(cmd, shell=isinstance(cmd, basestring), 690 bufsize=bufsize, stdin=PIPE, stdout=PIPE, 691 stderr=PIPE, close_fds=True) 692 return p.stdin, p.stdout, p.stderr

693 __all__.append("popen3") 694 695 if not _exists("popen4"):

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

697 """Execute the shell command 'cmd' in a sub-process. On UNIX, 'cmd' 698 may be a sequence, in which case arguments will be passed directly to 699 the program without shell intervention (as with os.spawnv()). If 'cmd' 700 is a string it will be passed to the shell (as with os.system()). If 701 'bufsize' is specified, it sets the buffer size for the I/O pipes. The 702 file objects (child_stdin, child_stdout_stderr) are returned.""" 703 import warnings 704 msg = "os.popen4 is deprecated. Use the subprocess module." 705 warnings.warn(msg, DeprecationWarning, stacklevel=2) 706 707 import subprocess 708 PIPE = subprocess.PIPE 709 p = subprocess.Popen(cmd, shell=isinstance(cmd, basestring), 710 bufsize=bufsize, stdin=PIPE, stdout=PIPE, 711 stderr=subprocess.STDOUT, close_fds=True) 712 return p.stdin, p.stdout

713 __all__.append("popen4") 714 715 import copy_reg as _copy_reg 716

717 -def _make_stat_result(tup, dict):

718 return stat_result(tup, dict)

719

720 -def _pickle_stat_result(sr):

721 (type, args) = sr.__reduce__() 722 return (_make_stat_result, args)

723 724 try: 725 _copy_reg.pickle(stat_result, _pickle_stat_result, _make_stat_result) 726 except NameError: # stat_result may not exist 727 pass 728

729 -def _make_statvfs_result(tup, dict):

730 return statvfs_result(tup, dict)

731

732 -def _pickle_statvfs_result(sr):

733 (type, args) = sr.__reduce__() 734 return (_make_statvfs_result, args)

735 736 try: 737 _copy_reg.pickle(statvfs_result, _pickle_statvfs_result, 738 _make_statvfs_result) 739 except NameError: # statvfs_result may not exist 740 pass 741

Source Code for Module os