1r"""UUID objects (universally unique identifiers) according to RFC 4122. 2 3This module provides immutable UUID objects (class UUID) and the functions 4uuid1(), uuid3(), uuid4(), uuid5() for generating version 1, 3, 4, and 5 5UUIDs as specified in RFC 4122. 6 7If all you want is a unique ID, you should probably call uuid1() or uuid4(). 8Note that uuid1() may compromise privacy since it creates a UUID containing 9the computer's network address. uuid4() creates a random UUID. 10 11Typical usage: 12 13 >>> import uuid 14 15 # make a UUID based on the host ID and current time 16 >>> uuid.uuid1() # doctest: +SKIP 17 UUID('a8098c1a-f86e-11da-bd1a-00112444be1e') 18 19 # make a UUID using an MD5 hash of a namespace UUID and a name 20 >>> uuid.uuid3(uuid.NAMESPACE_DNS, 'python.org') 21 UUID('6fa459ea-ee8a-3ca4-894e-db77e160355e') 22 23 # make a random UUID 24 >>> uuid.uuid4() # doctest: +SKIP 25 UUID('16fd2706-8baf-433b-82eb-8c7fada847da') 26 27 # make a UUID using a SHA-1 hash of a namespace UUID and a name 28 >>> uuid.uuid5(uuid.NAMESPACE_DNS, 'python.org') 29 UUID('886313e1-3b8a-5372-9b90-0c9aee199e5d') 30 31 # make a UUID from a string of hex digits (braces and hyphens ignored) 32 >>> x = uuid.UUID('{00010203-0405-0607-0809-0a0b0c0d0e0f}') 33 34 # convert a UUID to a string of hex digits in standard form 35 >>> str(x) 36 '00010203-0405-0607-0809-0a0b0c0d0e0f' 37 38 # get the raw 16 bytes of the UUID 39 >>> x.bytes 40 b'\x00\x01\x02\x03\x04\x05\x06\x07\x08\t\n\x0b\x0c\r\x0e\x0f' 41 42 # make a UUID from a 16-byte string 43 >>> uuid.UUID(bytes=x.bytes) 44 UUID('00010203-0405-0607-0809-0a0b0c0d0e0f') 45""" 46 47import os 48import platform 49import sys 50 51from enum import Enum 52 53 54__author__ = 'Ka-Ping Yee <ping@zesty.ca>' 55 56# The recognized platforms - known behaviors 57_AIX = platform.system() == 'AIX' 58_DARWIN = platform.system() == 'Darwin' 59_LINUX = platform.system() == 'Linux' 60_WINDOWS = platform.system() == 'Windows' 61 62RESERVED_NCS, RFC_4122, RESERVED_MICROSOFT, RESERVED_FUTURE = [ 63 'reserved for NCS compatibility', 'specified in RFC 4122', 64 'reserved for Microsoft compatibility', 'reserved for future definition'] 65 66int_ = int # The built-in int type 67bytes_ = bytes # The built-in bytes type 68 69 70class SafeUUID(Enum): 71 safe = 0 72 unsafe = -1 73 unknown = None 74 75 76class UUID: 77 """Instances of the UUID class represent UUIDs as specified in RFC 4122. 78 UUID objects are immutable, hashable, and usable as dictionary keys. 79 Converting a UUID to a string with str() yields something in the form 80 '12345678-1234-1234-1234-123456789abc'. The UUID constructor accepts 81 five possible forms: a similar string of hexadecimal digits, or a tuple 82 of six integer fields (with 32-bit, 16-bit, 16-bit, 8-bit, 8-bit, and 83 48-bit values respectively) as an argument named 'fields', or a string 84 of 16 bytes (with all the integer fields in big-endian order) as an 85 argument named 'bytes', or a string of 16 bytes (with the first three 86 fields in little-endian order) as an argument named 'bytes_le', or a 87 single 128-bit integer as an argument named 'int'. 88 89 UUIDs have these read-only attributes: 90 91 bytes the UUID as a 16-byte string (containing the six 92 integer fields in big-endian byte order) 93 94 bytes_le the UUID as a 16-byte string (with time_low, time_mid, 95 and time_hi_version in little-endian byte order) 96 97 fields a tuple of the six integer fields of the UUID, 98 which are also available as six individual attributes 99 and two derived attributes: 100 101 time_low the first 32 bits of the UUID 102 time_mid the next 16 bits of the UUID 103 time_hi_version the next 16 bits of the UUID 104 clock_seq_hi_variant the next 8 bits of the UUID 105 clock_seq_low the next 8 bits of the UUID 106 node the last 48 bits of the UUID 107 108 time the 60-bit timestamp 109 clock_seq the 14-bit sequence number 110 111 hex the UUID as a 32-character hexadecimal string 112 113 int the UUID as a 128-bit integer 114 115 urn the UUID as a URN as specified in RFC 4122 116 117 variant the UUID variant (one of the constants RESERVED_NCS, 118 RFC_4122, RESERVED_MICROSOFT, or RESERVED_FUTURE) 119 120 version the UUID version number (1 through 5, meaningful only 121 when the variant is RFC_4122) 122 123 is_safe An enum indicating whether the UUID has been generated in 124 a way that is safe for multiprocessing applications, via 125 uuid_generate_time_safe(3). 126 """ 127 128 __slots__ = ('int', 'is_safe', '__weakref__') 129 130 def __init__(self, hex=None, bytes=None, bytes_le=None, fields=None, 131 int=None, version=None, 132 *, is_safe=SafeUUID.unknown): 133 r"""Create a UUID from either a string of 32 hexadecimal digits, 134 a string of 16 bytes as the 'bytes' argument, a string of 16 bytes 135 in little-endian order as the 'bytes_le' argument, a tuple of six 136 integers (32-bit time_low, 16-bit time_mid, 16-bit time_hi_version, 137 8-bit clock_seq_hi_variant, 8-bit clock_seq_low, 48-bit node) as 138 the 'fields' argument, or a single 128-bit integer as the 'int' 139 argument. When a string of hex digits is given, curly braces, 140 hyphens, and a URN prefix are all optional. For example, these 141 expressions all yield the same UUID: 142 143 UUID('{12345678-1234-5678-1234-567812345678}') 144 UUID('12345678123456781234567812345678') 145 UUID('urn:uuid:12345678-1234-5678-1234-567812345678') 146 UUID(bytes='\x12\x34\x56\x78'*4) 147 UUID(bytes_le='\x78\x56\x34\x12\x34\x12\x78\x56' + 148 '\x12\x34\x56\x78\x12\x34\x56\x78') 149 UUID(fields=(0x12345678, 0x1234, 0x5678, 0x12, 0x34, 0x567812345678)) 150 UUID(int=0x12345678123456781234567812345678) 151 152 Exactly one of 'hex', 'bytes', 'bytes_le', 'fields', or 'int' must 153 be given. The 'version' argument is optional; if given, the resulting 154 UUID will have its variant and version set according to RFC 4122, 155 overriding the given 'hex', 'bytes', 'bytes_le', 'fields', or 'int'. 156 157 is_safe is an enum exposed as an attribute on the instance. It 158 indicates whether the UUID has been generated in a way that is safe 159 for multiprocessing applications, via uuid_generate_time_safe(3). 160 """ 161 162 if [hex, bytes, bytes_le, fields, int].count(None) != 4: 163 raise TypeError('one of the hex, bytes, bytes_le, fields, ' 164 'or int arguments must be given') 165 if hex is not None: 166 hex = hex.replace('urn:', '').replace('uuid:', '') 167 hex = hex.strip('{}').replace('-', '') 168 if len(hex) != 32: 169 raise ValueError('badly formed hexadecimal UUID string') 170 int = int_(hex, 16) 171 if bytes_le is not None: 172 if len(bytes_le) != 16: 173 raise ValueError('bytes_le is not a 16-char string') 174 bytes = (bytes_le[4-1::-1] + bytes_le[6-1:4-1:-1] + 175 bytes_le[8-1:6-1:-1] + bytes_le[8:]) 176 if bytes is not None: 177 if len(bytes) != 16: 178 raise ValueError('bytes is not a 16-char string') 179 assert isinstance(bytes, bytes_), repr(bytes) 180 int = int_.from_bytes(bytes, byteorder='big') 181 if fields is not None: 182 if len(fields) != 6: 183 raise ValueError('fields is not a 6-tuple') 184 (time_low, time_mid, time_hi_version, 185 clock_seq_hi_variant, clock_seq_low, node) = fields 186 if not 0 <= time_low < 1<<32: 187 raise ValueError('field 1 out of range (need a 32-bit value)') 188 if not 0 <= time_mid < 1<<16: 189 raise ValueError('field 2 out of range (need a 16-bit value)') 190 if not 0 <= time_hi_version < 1<<16: 191 raise ValueError('field 3 out of range (need a 16-bit value)') 192 if not 0 <= clock_seq_hi_variant < 1<<8: 193 raise ValueError('field 4 out of range (need an 8-bit value)') 194 if not 0 <= clock_seq_low < 1<<8: 195 raise ValueError('field 5 out of range (need an 8-bit value)') 196 if not 0 <= node < 1<<48: 197 raise ValueError('field 6 out of range (need a 48-bit value)') 198 clock_seq = (clock_seq_hi_variant << 8) | clock_seq_low 199 int = ((time_low << 96) | (time_mid << 80) | 200 (time_hi_version << 64) | (clock_seq << 48) | node) 201 if int is not None: 202 if not 0 <= int < 1<<128: 203 raise ValueError('int is out of range (need a 128-bit value)') 204 if version is not None: 205 if not 1 <= version <= 5: 206 raise ValueError('illegal version number') 207 # Set the variant to RFC 4122. 208 int &= ~(0xc000 << 48) 209 int |= 0x8000 << 48 210 # Set the version number. 211 int &= ~(0xf000 << 64) 212 int |= version << 76 213 object.__setattr__(self, 'int', int) 214 object.__setattr__(self, 'is_safe', is_safe) 215 216 def __getstate__(self): 217 d = {'int': self.int} 218 if self.is_safe != SafeUUID.unknown: 219 # is_safe is a SafeUUID instance. Return just its value, so that 220 # it can be un-pickled in older Python versions without SafeUUID. 221 d['is_safe'] = self.is_safe.value 222 return d 223 224 def __setstate__(self, state): 225 object.__setattr__(self, 'int', state['int']) 226 # is_safe was added in 3.7; it is also omitted when it is "unknown" 227 object.__setattr__(self, 'is_safe', 228 SafeUUID(state['is_safe']) 229 if 'is_safe' in state else SafeUUID.unknown) 230 231 def __eq__(self, other): 232 if isinstance(other, UUID): 233 return self.int == other.int 234 return NotImplemented 235 236 # Q. What's the value of being able to sort UUIDs? 237 # A. Use them as keys in a B-Tree or similar mapping. 238 239 def __lt__(self, other): 240 if isinstance(other, UUID): 241 return self.int < other.int 242 return NotImplemented 243 244 def __gt__(self, other): 245 if isinstance(other, UUID): 246 return self.int > other.int 247 return NotImplemented 248 249 def __le__(self, other): 250 if isinstance(other, UUID): 251 return self.int <= other.int 252 return NotImplemented 253 254 def __ge__(self, other): 255 if isinstance(other, UUID): 256 return self.int >= other.int 257 return NotImplemented 258 259 def __hash__(self): 260 return hash(self.int) 261 262 def __int__(self): 263 return self.int 264 265 def __repr__(self): 266 return '%s(%r)' % (self.__class__.__name__, str(self)) 267 268 def __setattr__(self, name, value): 269 raise TypeError('UUID objects are immutable') 270 271 def __str__(self): 272 hex = '%032x' % self.int 273 return '%s-%s-%s-%s-%s' % ( 274 hex[:8], hex[8:12], hex[12:16], hex[16:20], hex[20:]) 275 276 @property 277 def bytes(self): 278 return self.int.to_bytes(16, 'big') 279 280 @property 281 def bytes_le(self): 282 bytes = self.bytes 283 return (bytes[4-1::-1] + bytes[6-1:4-1:-1] + bytes[8-1:6-1:-1] + 284 bytes[8:]) 285 286 @property 287 def fields(self): 288 return (self.time_low, self.time_mid, self.time_hi_version, 289 self.clock_seq_hi_variant, self.clock_seq_low, self.node) 290 291 @property 292 def time_low(self): 293 return self.int >> 96 294 295 @property 296 def time_mid(self): 297 return (self.int >> 80) & 0xffff 298 299 @property 300 def time_hi_version(self): 301 return (self.int >> 64) & 0xffff 302 303 @property 304 def clock_seq_hi_variant(self): 305 return (self.int >> 56) & 0xff 306 307 @property 308 def clock_seq_low(self): 309 return (self.int >> 48) & 0xff 310 311 @property 312 def time(self): 313 return (((self.time_hi_version & 0x0fff) << 48) | 314 (self.time_mid << 32) | self.time_low) 315 316 @property 317 def clock_seq(self): 318 return (((self.clock_seq_hi_variant & 0x3f) << 8) | 319 self.clock_seq_low) 320 321 @property 322 def node(self): 323 return self.int & 0xffffffffffff 324 325 @property 326 def hex(self): 327 return '%032x' % self.int 328 329 @property 330 def urn(self): 331 return 'urn:uuid:' + str(self) 332 333 @property 334 def variant(self): 335 if not self.int & (0x8000 << 48): 336 return RESERVED_NCS 337 elif not self.int & (0x4000 << 48): 338 return RFC_4122 339 elif not self.int & (0x2000 << 48): 340 return RESERVED_MICROSOFT 341 else: 342 return RESERVED_FUTURE 343 344 @property 345 def version(self): 346 # The version bits are only meaningful for RFC 4122 UUIDs. 347 if self.variant == RFC_4122: 348 return int((self.int >> 76) & 0xf) 349 350def _popen(command, *args): 351 import os, shutil, subprocess 352 executable = shutil.which(command) 353 if executable is None: 354 path = os.pathsep.join(('/sbin', '/usr/sbin')) 355 executable = shutil.which(command, path=path) 356 if executable is None: 357 return None 358 # LC_ALL=C to ensure English output, stderr=DEVNULL to prevent output 359 # on stderr (Note: we don't have an example where the words we search 360 # for are actually localized, but in theory some system could do so.) 361 env = dict(os.environ) 362 env['LC_ALL'] = 'C' 363 proc = subprocess.Popen((executable,) + args, 364 stdout=subprocess.PIPE, 365 stderr=subprocess.DEVNULL, 366 env=env) 367 return proc 368 369# For MAC (a.k.a. IEEE 802, or EUI-48) addresses, the second least significant 370# bit of the first octet signifies whether the MAC address is universally (0) 371# or locally (1) administered. Network cards from hardware manufacturers will 372# always be universally administered to guarantee global uniqueness of the MAC 373# address, but any particular machine may have other interfaces which are 374# locally administered. An example of the latter is the bridge interface to 375# the Touch Bar on MacBook Pros. 376# 377# This bit works out to be the 42nd bit counting from 1 being the least 378# significant, or 1<<41. We'll prefer universally administered MAC addresses 379# over locally administered ones since the former are globally unique, but 380# we'll return the first of the latter found if that's all the machine has. 381# 382# See https://en.wikipedia.org/wiki/MAC_address#Universal_vs._local 383 384def _is_universal(mac): 385 return not (mac & (1 << 41)) 386 387def _find_mac(command, args, hw_identifiers, get_index): 388 first_local_mac = None 389 try: 390 proc = _popen(command, *args.split()) 391 if not proc: 392 return None 393 with proc: 394 for line in proc.stdout: 395 words = line.lower().rstrip().split() 396 for i in range(len(words)): 397 if words[i] in hw_identifiers: 398 try: 399 word = words[get_index(i)] 400 mac = int(word.replace(b':', b''), 16) 401 if _is_universal(mac): 402 return mac 403 first_local_mac = first_local_mac or mac 404 except (ValueError, IndexError): 405 # Virtual interfaces, such as those provided by 406 # VPNs, do not have a colon-delimited MAC address 407 # as expected, but a 16-byte HWAddr separated by 408 # dashes. These should be ignored in favor of a 409 # real MAC address 410 pass 411 except OSError: 412 pass 413 return first_local_mac or None 414 415def _ifconfig_getnode(): 416 """Get the hardware address on Unix by running ifconfig.""" 417 # This works on Linux ('' or '-a'), Tru64 ('-av'), but not all Unixes. 418 keywords = (b'hwaddr', b'ether', b'address:', b'lladdr') 419 for args in ('', '-a', '-av'): 420 mac = _find_mac('ifconfig', args, keywords, lambda i: i+1) 421 if mac: 422 return mac 423 return None 424 425def _ip_getnode(): 426 """Get the hardware address on Unix by running ip.""" 427 # This works on Linux with iproute2. 428 mac = _find_mac('ip', 'link', [b'link/ether'], lambda i: i+1) 429 if mac: 430 return mac 431 return None 432 433def _arp_getnode(): 434 """Get the hardware address on Unix by running arp.""" 435 import os, socket 436 try: 437 ip_addr = socket.gethostbyname(socket.gethostname()) 438 except OSError: 439 return None 440 441 # Try getting the MAC addr from arp based on our IP address (Solaris). 442 mac = _find_mac('arp', '-an', [os.fsencode(ip_addr)], lambda i: -1) 443 if mac: 444 return mac 445 446 # This works on OpenBSD 447 mac = _find_mac('arp', '-an', [os.fsencode(ip_addr)], lambda i: i+1) 448 if mac: 449 return mac 450 451 # This works on Linux, FreeBSD and NetBSD 452 mac = _find_mac('arp', '-an', [os.fsencode('(%s)' % ip_addr)], 453 lambda i: i+2) 454 # Return None instead of 0. 455 if mac: 456 return mac 457 return None 458 459def _lanscan_getnode(): 460 """Get the hardware address on Unix by running lanscan.""" 461 # This might work on HP-UX. 462 return _find_mac('lanscan', '-ai', [b'lan0'], lambda i: 0) 463 464def _netstat_getnode(): 465 """Get the hardware address on Unix by running netstat.""" 466 # This might work on AIX, Tru64 UNIX. 467 first_local_mac = None 468 try: 469 proc = _popen('netstat', '-ia') 470 if not proc: 471 return None 472 with proc: 473 words = proc.stdout.readline().rstrip().split() 474 try: 475 i = words.index(b'Address') 476 except ValueError: 477 return None 478 for line in proc.stdout: 479 try: 480 words = line.rstrip().split() 481 word = words[i] 482 if len(word) == 17 and word.count(b':') == 5: 483 mac = int(word.replace(b':', b''), 16) 484 if _is_universal(mac): 485 return mac 486 first_local_mac = first_local_mac or mac 487 except (ValueError, IndexError): 488 pass 489 except OSError: 490 pass 491 return first_local_mac or None 492 493def _ipconfig_getnode(): 494 """Get the hardware address on Windows by running ipconfig.exe.""" 495 import os, re, subprocess 496 first_local_mac = None 497 dirs = ['', r'c:\windows\system32', r'c:\winnt\system32'] 498 try: 499 import ctypes 500 buffer = ctypes.create_string_buffer(300) 501 ctypes.windll.kernel32.GetSystemDirectoryA(buffer, 300) 502 dirs.insert(0, buffer.value.decode('mbcs')) 503 except: 504 pass 505 for dir in dirs: 506 try: 507 proc = subprocess.Popen([os.path.join(dir, 'ipconfig'), '/all'], 508 stdout=subprocess.PIPE, 509 encoding="oem") 510 except OSError: 511 continue 512 with proc: 513 for line in proc.stdout: 514 value = line.split(':')[-1].strip().lower() 515 if re.fullmatch('(?:[0-9a-f][0-9a-f]-){5}[0-9a-f][0-9a-f]', value): 516 mac = int(value.replace('-', ''), 16) 517 if _is_universal(mac): 518 return mac 519 first_local_mac = first_local_mac or mac 520 return first_local_mac or None 521 522def _netbios_getnode(): 523 """Get the hardware address on Windows using NetBIOS calls. 524 See http://support.microsoft.com/kb/118623 for details.""" 525 import win32wnet, netbios 526 first_local_mac = None 527 ncb = netbios.NCB() 528 ncb.Command = netbios.NCBENUM 529 ncb.Buffer = adapters = netbios.LANA_ENUM() 530 adapters._pack() 531 if win32wnet.Netbios(ncb) != 0: 532 return None 533 adapters._unpack() 534 for i in range(adapters.length): 535 ncb.Reset() 536 ncb.Command = netbios.NCBRESET 537 ncb.Lana_num = ord(adapters.lana[i]) 538 if win32wnet.Netbios(ncb) != 0: 539 continue 540 ncb.Reset() 541 ncb.Command = netbios.NCBASTAT 542 ncb.Lana_num = ord(adapters.lana[i]) 543 ncb.Callname = '*'.ljust(16) 544 ncb.Buffer = status = netbios.ADAPTER_STATUS() 545 if win32wnet.Netbios(ncb) != 0: 546 continue 547 status._unpack() 548 bytes = status.adapter_address[:6] 549 if len(bytes) != 6: 550 continue 551 mac = int.from_bytes(bytes, 'big') 552 if _is_universal(mac): 553 return mac 554 first_local_mac = first_local_mac or mac 555 return first_local_mac or None 556 557 558_generate_time_safe = _UuidCreate = None 559_has_uuid_generate_time_safe = None 560 561# Import optional C extension at toplevel, to help disabling it when testing 562try: 563 import _uuid 564except ImportError: 565 _uuid = None 566 567 568def _load_system_functions(): 569 """ 570 Try to load platform-specific functions for generating uuids. 571 """ 572 global _generate_time_safe, _UuidCreate, _has_uuid_generate_time_safe 573 574 if _has_uuid_generate_time_safe is not None: 575 return 576 577 _has_uuid_generate_time_safe = False 578 579 if sys.platform == "darwin" and int(os.uname().release.split('.')[0]) < 9: 580 # The uuid_generate_* functions are broken on MacOS X 10.5, as noted 581 # in issue #8621 the function generates the same sequence of values 582 # in the parent process and all children created using fork (unless 583 # those children use exec as well). 584 # 585 # Assume that the uuid_generate functions are broken from 10.5 onward, 586 # the test can be adjusted when a later version is fixed. 587 pass 588 elif _uuid is not None: 589 _generate_time_safe = _uuid.generate_time_safe 590 _has_uuid_generate_time_safe = _uuid.has_uuid_generate_time_safe 591 return 592 593 try: 594 # If we couldn't find an extension module, try ctypes to find 595 # system routines for UUID generation. 596 # Thanks to Thomas Heller for ctypes and for his help with its use here. 597 import ctypes 598 import ctypes.util 599 600 # The uuid_generate_* routines are provided by libuuid on at least 601 # Linux and FreeBSD, and provided by libc on Mac OS X. 602 _libnames = ['uuid'] 603 if not sys.platform.startswith('win'): 604 _libnames.append('c') 605 for libname in _libnames: 606 try: 607 lib = ctypes.CDLL(ctypes.util.find_library(libname)) 608 except Exception: # pragma: nocover 609 continue 610 # Try to find the safe variety first. 611 if hasattr(lib, 'uuid_generate_time_safe'): 612 _uuid_generate_time_safe = lib.uuid_generate_time_safe 613 # int uuid_generate_time_safe(uuid_t out); 614 def _generate_time_safe(): 615 _buffer = ctypes.create_string_buffer(16) 616 res = _uuid_generate_time_safe(_buffer) 617 return bytes(_buffer.raw), res 618 _has_uuid_generate_time_safe = True 619 break 620 621 elif hasattr(lib, 'uuid_generate_time'): # pragma: nocover 622 _uuid_generate_time = lib.uuid_generate_time 623 # void uuid_generate_time(uuid_t out); 624 _uuid_generate_time.restype = None 625 def _generate_time_safe(): 626 _buffer = ctypes.create_string_buffer(16) 627 _uuid_generate_time(_buffer) 628 return bytes(_buffer.raw), None 629 break 630 631 # On Windows prior to 2000, UuidCreate gives a UUID containing the 632 # hardware address. On Windows 2000 and later, UuidCreate makes a 633 # random UUID and UuidCreateSequential gives a UUID containing the 634 # hardware address. These routines are provided by the RPC runtime. 635 # NOTE: at least on Tim's WinXP Pro SP2 desktop box, while the last 636 # 6 bytes returned by UuidCreateSequential are fixed, they don't appear 637 # to bear any relationship to the MAC address of any network device 638 # on the box. 639 try: 640 lib = ctypes.windll.rpcrt4 641 except: 642 lib = None 643 _UuidCreate = getattr(lib, 'UuidCreateSequential', 644 getattr(lib, 'UuidCreate', None)) 645 646 except Exception as exc: 647 import warnings 648 warnings.warn(f"Could not find fallback ctypes uuid functions: {exc}", 649 ImportWarning) 650 651 652def _unix_getnode(): 653 """Get the hardware address on Unix using the _uuid extension module 654 or ctypes.""" 655 _load_system_functions() 656 uuid_time, _ = _generate_time_safe() 657 return UUID(bytes=uuid_time).node 658 659def _windll_getnode(): 660 """Get the hardware address on Windows using ctypes.""" 661 import ctypes 662 _load_system_functions() 663 _buffer = ctypes.create_string_buffer(16) 664 if _UuidCreate(_buffer) == 0: 665 return UUID(bytes=bytes_(_buffer.raw)).node 666 667def _random_getnode(): 668 """Get a random node ID.""" 669 # RFC 4122, $4.1.6 says "For systems with no IEEE address, a randomly or 670 # pseudo-randomly generated value may be used; see Section 4.5. The 671 # multicast bit must be set in such addresses, in order that they will 672 # never conflict with addresses obtained from network cards." 673 # 674 # The "multicast bit" of a MAC address is defined to be "the least 675 # significant bit of the first octet". This works out to be the 41st bit 676 # counting from 1 being the least significant bit, or 1<<40. 677 # 678 # See https://en.wikipedia.org/wiki/MAC_address#Unicast_vs._multicast 679 import random 680 return random.getrandbits(48) | (1 << 40) 681 682 683# _OS_GETTERS, when known, are targeted for a specific OS or platform. 684# The order is by 'common practice' on the specified platform. 685# Note: 'posix' and 'windows' _OS_GETTERS are prefixed by a dll/dlload() method 686# which, when successful, means none of these "external" methods are called. 687# _GETTERS is (also) used by test_uuid.py to SkipUnless(), e.g., 688# @unittest.skipUnless(_uuid._ifconfig_getnode in _uuid._GETTERS, ...) 689if _LINUX: 690 _OS_GETTERS = [_ip_getnode, _ifconfig_getnode] 691elif _DARWIN: 692 _OS_GETTERS = [_ifconfig_getnode, _arp_getnode, _netstat_getnode] 693elif _WINDOWS: 694 _OS_GETTERS = [_netbios_getnode, _ipconfig_getnode] 695elif _AIX: 696 _OS_GETTERS = [_netstat_getnode] 697else: 698 _OS_GETTERS = [_ifconfig_getnode, _ip_getnode, _arp_getnode, 699 _netstat_getnode, _lanscan_getnode] 700if os.name == 'posix': 701 _GETTERS = [_unix_getnode] + _OS_GETTERS 702elif os.name == 'nt': 703 _GETTERS = [_windll_getnode] + _OS_GETTERS 704else: 705 _GETTERS = _OS_GETTERS 706 707_node = None 708 709def getnode(*, getters=None): 710 """Get the hardware address as a 48-bit positive integer. 711 712 The first time this runs, it may launch a separate program, which could 713 be quite slow. If all attempts to obtain the hardware address fail, we 714 choose a random 48-bit number with its eighth bit set to 1 as recommended 715 in RFC 4122. 716 """ 717 global _node 718 if _node is not None: 719 return _node 720 721 for getter in _GETTERS + [_random_getnode]: 722 try: 723 _node = getter() 724 except: 725 continue 726 if (_node is not None) and (0 <= _node < (1 << 48)): 727 return _node 728 assert False, '_random_getnode() returned invalid value: {}'.format(_node) 729 730 731_last_timestamp = None 732 733def uuid1(node=None, clock_seq=None): 734 """Generate a UUID from a host ID, sequence number, and the current time. 735 If 'node' is not given, getnode() is used to obtain the hardware 736 address. If 'clock_seq' is given, it is used as the sequence number; 737 otherwise a random 14-bit sequence number is chosen.""" 738 739 # When the system provides a version-1 UUID generator, use it (but don't 740 # use UuidCreate here because its UUIDs don't conform to RFC 4122). 741 _load_system_functions() 742 if _generate_time_safe is not None and node is clock_seq is None: 743 uuid_time, safely_generated = _generate_time_safe() 744 try: 745 is_safe = SafeUUID(safely_generated) 746 except ValueError: 747 is_safe = SafeUUID.unknown 748 return UUID(bytes=uuid_time, is_safe=is_safe) 749 750 global _last_timestamp 751 import time 752 nanoseconds = time.time_ns() 753 # 0x01b21dd213814000 is the number of 100-ns intervals between the 754 # UUID epoch 1582-10-15 00:00:00 and the Unix epoch 1970-01-01 00:00:00. 755 timestamp = nanoseconds // 100 + 0x01b21dd213814000 756 if _last_timestamp is not None and timestamp <= _last_timestamp: 757 timestamp = _last_timestamp + 1 758 _last_timestamp = timestamp 759 if clock_seq is None: 760 import random 761 clock_seq = random.getrandbits(14) # instead of stable storage 762 time_low = timestamp & 0xffffffff 763 time_mid = (timestamp >> 32) & 0xffff 764 time_hi_version = (timestamp >> 48) & 0x0fff 765 clock_seq_low = clock_seq & 0xff 766 clock_seq_hi_variant = (clock_seq >> 8) & 0x3f 767 if node is None: 768 node = getnode() 769 return UUID(fields=(time_low, time_mid, time_hi_version, 770 clock_seq_hi_variant, clock_seq_low, node), version=1) 771 772def uuid3(namespace, name): 773 """Generate a UUID from the MD5 hash of a namespace UUID and a name.""" 774 from hashlib import md5 775 hash = md5(namespace.bytes + bytes(name, "utf-8")).digest() 776 return UUID(bytes=hash[:16], version=3) 777 778def uuid4(): 779 """Generate a random UUID.""" 780 return UUID(bytes=os.urandom(16), version=4) 781 782def uuid5(namespace, name): 783 """Generate a UUID from the SHA-1 hash of a namespace UUID and a name.""" 784 from hashlib import sha1 785 hash = sha1(namespace.bytes + bytes(name, "utf-8")).digest() 786 return UUID(bytes=hash[:16], version=5) 787 788# The following standard UUIDs are for use with uuid3() or uuid5(). 789 790NAMESPACE_DNS = UUID('6ba7b810-9dad-11d1-80b4-00c04fd430c8') 791NAMESPACE_URL = UUID('6ba7b811-9dad-11d1-80b4-00c04fd430c8') 792NAMESPACE_OID = UUID('6ba7b812-9dad-11d1-80b4-00c04fd430c8') 793NAMESPACE_X500 = UUID('6ba7b814-9dad-11d1-80b4-00c04fd430c8') 794