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 sys 49 50from enum import Enum 51 52 53__author__ = 'Ka-Ping Yee <ping@zesty.ca>' 54 55RESERVED_NCS, RFC_4122, RESERVED_MICROSOFT, RESERVED_FUTURE = [ 56 'reserved for NCS compatibility', 'specified in RFC 4122', 57 'reserved for Microsoft compatibility', 'reserved for future definition'] 58 59int_ = int # The built-in int type 60bytes_ = bytes # The built-in bytes type 61 62 63class SafeUUID(Enum): 64 safe = 0 65 unsafe = -1 66 unknown = None 67 68 69class UUID: 70 """Instances of the UUID class represent UUIDs as specified in RFC 4122. 71 UUID objects are immutable, hashable, and usable as dictionary keys. 72 Converting a UUID to a string with str() yields something in the form 73 '12345678-1234-1234-1234-123456789abc'. The UUID constructor accepts 74 five possible forms: a similar string of hexadecimal digits, or a tuple 75 of six integer fields (with 32-bit, 16-bit, 16-bit, 8-bit, 8-bit, and 76 48-bit values respectively) as an argument named 'fields', or a string 77 of 16 bytes (with all the integer fields in big-endian order) as an 78 argument named 'bytes', or a string of 16 bytes (with the first three 79 fields in little-endian order) as an argument named 'bytes_le', or a 80 single 128-bit integer as an argument named 'int'. 81 82 UUIDs have these read-only attributes: 83 84 bytes the UUID as a 16-byte string (containing the six 85 integer fields in big-endian byte order) 86 87 bytes_le the UUID as a 16-byte string (with time_low, time_mid, 88 and time_hi_version in little-endian byte order) 89 90 fields a tuple of the six integer fields of the UUID, 91 which are also available as six individual attributes 92 and two derived attributes: 93 94 time_low the first 32 bits of the UUID 95 time_mid the next 16 bits of the UUID 96 time_hi_version the next 16 bits of the UUID 97 clock_seq_hi_variant the next 8 bits of the UUID 98 clock_seq_low the next 8 bits of the UUID 99 node the last 48 bits of the UUID 100 101 time the 60-bit timestamp 102 clock_seq the 14-bit sequence number 103 104 hex the UUID as a 32-character hexadecimal string 105 106 int the UUID as a 128-bit integer 107 108 urn the UUID as a URN as specified in RFC 4122 109 110 variant the UUID variant (one of the constants RESERVED_NCS, 111 RFC_4122, RESERVED_MICROSOFT, or RESERVED_FUTURE) 112 113 version the UUID version number (1 through 5, meaningful only 114 when the variant is RFC_4122) 115 116 is_safe An enum indicating whether the UUID has been generated in 117 a way that is safe for multiprocessing applications, via 118 uuid_generate_time_safe(3). 119 """ 120 121 def __init__(self, hex=None, bytes=None, bytes_le=None, fields=None, 122 int=None, version=None, 123 *, is_safe=SafeUUID.unknown): 124 r"""Create a UUID from either a string of 32 hexadecimal digits, 125 a string of 16 bytes as the 'bytes' argument, a string of 16 bytes 126 in little-endian order as the 'bytes_le' argument, a tuple of six 127 integers (32-bit time_low, 16-bit time_mid, 16-bit time_hi_version, 128 8-bit clock_seq_hi_variant, 8-bit clock_seq_low, 48-bit node) as 129 the 'fields' argument, or a single 128-bit integer as the 'int' 130 argument. When a string of hex digits is given, curly braces, 131 hyphens, and a URN prefix are all optional. For example, these 132 expressions all yield the same UUID: 133 134 UUID('{12345678-1234-5678-1234-567812345678}') 135 UUID('12345678123456781234567812345678') 136 UUID('urn:uuid:12345678-1234-5678-1234-567812345678') 137 UUID(bytes='\x12\x34\x56\x78'*4) 138 UUID(bytes_le='\x78\x56\x34\x12\x34\x12\x78\x56' + 139 '\x12\x34\x56\x78\x12\x34\x56\x78') 140 UUID(fields=(0x12345678, 0x1234, 0x5678, 0x12, 0x34, 0x567812345678)) 141 UUID(int=0x12345678123456781234567812345678) 142 143 Exactly one of 'hex', 'bytes', 'bytes_le', 'fields', or 'int' must 144 be given. The 'version' argument is optional; if given, the resulting 145 UUID will have its variant and version set according to RFC 4122, 146 overriding the given 'hex', 'bytes', 'bytes_le', 'fields', or 'int'. 147 148 is_safe is an enum exposed as an attribute on the instance. It 149 indicates whether the UUID has been generated in a way that is safe 150 for multiprocessing applications, via uuid_generate_time_safe(3). 151 """ 152 153 if [hex, bytes, bytes_le, fields, int].count(None) != 4: 154 raise TypeError('one of the hex, bytes, bytes_le, fields, ' 155 'or int arguments must be given') 156 if hex is not None: 157 hex = hex.replace('urn:', '').replace('uuid:', '') 158 hex = hex.strip('{}').replace('-', '') 159 if len(hex) != 32: 160 raise ValueError('badly formed hexadecimal UUID string') 161 int = int_(hex, 16) 162 if bytes_le is not None: 163 if len(bytes_le) != 16: 164 raise ValueError('bytes_le is not a 16-char string') 165 bytes = (bytes_le[4-1::-1] + bytes_le[6-1:4-1:-1] + 166 bytes_le[8-1:6-1:-1] + bytes_le[8:]) 167 if bytes is not None: 168 if len(bytes) != 16: 169 raise ValueError('bytes is not a 16-char string') 170 assert isinstance(bytes, bytes_), repr(bytes) 171 int = int_.from_bytes(bytes, byteorder='big') 172 if fields is not None: 173 if len(fields) != 6: 174 raise ValueError('fields is not a 6-tuple') 175 (time_low, time_mid, time_hi_version, 176 clock_seq_hi_variant, clock_seq_low, node) = fields 177 if not 0 <= time_low < 1<<32: 178 raise ValueError('field 1 out of range (need a 32-bit value)') 179 if not 0 <= time_mid < 1<<16: 180 raise ValueError('field 2 out of range (need a 16-bit value)') 181 if not 0 <= time_hi_version < 1<<16: 182 raise ValueError('field 3 out of range (need a 16-bit value)') 183 if not 0 <= clock_seq_hi_variant < 1<<8: 184 raise ValueError('field 4 out of range (need an 8-bit value)') 185 if not 0 <= clock_seq_low < 1<<8: 186 raise ValueError('field 5 out of range (need an 8-bit value)') 187 if not 0 <= node < 1<<48: 188 raise ValueError('field 6 out of range (need a 48-bit value)') 189 clock_seq = (clock_seq_hi_variant << 8) | clock_seq_low 190 int = ((time_low << 96) | (time_mid << 80) | 191 (time_hi_version << 64) | (clock_seq << 48) | node) 192 if int is not None: 193 if not 0 <= int < 1<<128: 194 raise ValueError('int is out of range (need a 128-bit value)') 195 if version is not None: 196 if not 1 <= version <= 5: 197 raise ValueError('illegal version number') 198 # Set the variant to RFC 4122. 199 int &= ~(0xc000 << 48) 200 int |= 0x8000 << 48 201 # Set the version number. 202 int &= ~(0xf000 << 64) 203 int |= version << 76 204 self.__dict__['int'] = int 205 self.__dict__['is_safe'] = is_safe 206 207 def __getstate__(self): 208 state = self.__dict__ 209 if self.is_safe != SafeUUID.unknown: 210 # is_safe is a SafeUUID instance. Return just its value, so that 211 # it can be un-pickled in older Python versions without SafeUUID. 212 state = state.copy() 213 state['is_safe'] = self.is_safe.value 214 return state 215 216 def __setstate__(self, state): 217 self.__dict__.update(state) 218 # is_safe was added in 3.7; it is also omitted when it is "unknown" 219 self.__dict__['is_safe'] = ( 220 SafeUUID(state['is_safe']) 221 if 'is_safe' in state else SafeUUID.unknown 222 ) 223 224 def __eq__(self, other): 225 if isinstance(other, UUID): 226 return self.int == other.int 227 return NotImplemented 228 229 # Q. What's the value of being able to sort UUIDs? 230 # A. Use them as keys in a B-Tree or similar mapping. 231 232 def __lt__(self, other): 233 if isinstance(other, UUID): 234 return self.int < other.int 235 return NotImplemented 236 237 def __gt__(self, other): 238 if isinstance(other, UUID): 239 return self.int > other.int 240 return NotImplemented 241 242 def __le__(self, other): 243 if isinstance(other, UUID): 244 return self.int <= other.int 245 return NotImplemented 246 247 def __ge__(self, other): 248 if isinstance(other, UUID): 249 return self.int >= other.int 250 return NotImplemented 251 252 def __hash__(self): 253 return hash(self.int) 254 255 def __int__(self): 256 return self.int 257 258 def __repr__(self): 259 return '%s(%r)' % (self.__class__.__name__, str(self)) 260 261 def __setattr__(self, name, value): 262 raise TypeError('UUID objects are immutable') 263 264 def __str__(self): 265 hex = '%032x' % self.int 266 return '%s-%s-%s-%s-%s' % ( 267 hex[:8], hex[8:12], hex[12:16], hex[16:20], hex[20:]) 268 269 @property 270 def bytes(self): 271 return self.int.to_bytes(16, 'big') 272 273 @property 274 def bytes_le(self): 275 bytes = self.bytes 276 return (bytes[4-1::-1] + bytes[6-1:4-1:-1] + bytes[8-1:6-1:-1] + 277 bytes[8:]) 278 279 @property 280 def fields(self): 281 return (self.time_low, self.time_mid, self.time_hi_version, 282 self.clock_seq_hi_variant, self.clock_seq_low, self.node) 283 284 @property 285 def time_low(self): 286 return self.int >> 96 287 288 @property 289 def time_mid(self): 290 return (self.int >> 80) & 0xffff 291 292 @property 293 def time_hi_version(self): 294 return (self.int >> 64) & 0xffff 295 296 @property 297 def clock_seq_hi_variant(self): 298 return (self.int >> 56) & 0xff 299 300 @property 301 def clock_seq_low(self): 302 return (self.int >> 48) & 0xff 303 304 @property 305 def time(self): 306 return (((self.time_hi_version & 0x0fff) << 48) | 307 (self.time_mid << 32) | self.time_low) 308 309 @property 310 def clock_seq(self): 311 return (((self.clock_seq_hi_variant & 0x3f) << 8) | 312 self.clock_seq_low) 313 314 @property 315 def node(self): 316 return self.int & 0xffffffffffff 317 318 @property 319 def hex(self): 320 return '%032x' % self.int 321 322 @property 323 def urn(self): 324 return 'urn:uuid:' + str(self) 325 326 @property 327 def variant(self): 328 if not self.int & (0x8000 << 48): 329 return RESERVED_NCS 330 elif not self.int & (0x4000 << 48): 331 return RFC_4122 332 elif not self.int & (0x2000 << 48): 333 return RESERVED_MICROSOFT 334 else: 335 return RESERVED_FUTURE 336 337 @property 338 def version(self): 339 # The version bits are only meaningful for RFC 4122 UUIDs. 340 if self.variant == RFC_4122: 341 return int((self.int >> 76) & 0xf) 342 343def _popen(command, *args): 344 import os, shutil, subprocess 345 executable = shutil.which(command) 346 if executable is None: 347 path = os.pathsep.join(('/sbin', '/usr/sbin')) 348 executable = shutil.which(command, path=path) 349 if executable is None: 350 return None 351 # LC_ALL=C to ensure English output, stderr=DEVNULL to prevent output 352 # on stderr (Note: we don't have an example where the words we search 353 # for are actually localized, but in theory some system could do so.) 354 env = dict(os.environ) 355 env['LC_ALL'] = 'C' 356 proc = subprocess.Popen((executable,) + args, 357 stdout=subprocess.PIPE, 358 stderr=subprocess.DEVNULL, 359 env=env) 360 return proc 361 362# For MAC (a.k.a. IEEE 802, or EUI-48) addresses, the second least significant 363# bit of the first octet signifies whether the MAC address is universally (0) 364# or locally (1) administered. Network cards from hardware manufacturers will 365# always be universally administered to guarantee global uniqueness of the MAC 366# address, but any particular machine may have other interfaces which are 367# locally administered. An example of the latter is the bridge interface to 368# the Touch Bar on MacBook Pros. 369# 370# This bit works out to be the 42nd bit counting from 1 being the least 371# significant, or 1<<41. We'll prefer universally administered MAC addresses 372# over locally administered ones since the former are globally unique, but 373# we'll return the first of the latter found if that's all the machine has. 374# 375# See https://en.wikipedia.org/wiki/MAC_address#Universal_vs._local 376 377def _is_universal(mac): 378 return not (mac & (1 << 41)) 379 380def _find_mac(command, args, hw_identifiers, get_index): 381 first_local_mac = None 382 try: 383 proc = _popen(command, *args.split()) 384 if not proc: 385 return None 386 with proc: 387 for line in proc.stdout: 388 words = line.lower().rstrip().split() 389 for i in range(len(words)): 390 if words[i] in hw_identifiers: 391 try: 392 word = words[get_index(i)] 393 mac = int(word.replace(b':', b''), 16) 394 if _is_universal(mac): 395 return mac 396 first_local_mac = first_local_mac or mac 397 except (ValueError, IndexError): 398 # Virtual interfaces, such as those provided by 399 # VPNs, do not have a colon-delimited MAC address 400 # as expected, but a 16-byte HWAddr separated by 401 # dashes. These should be ignored in favor of a 402 # real MAC address 403 pass 404 except OSError: 405 pass 406 return first_local_mac or None 407 408def _ifconfig_getnode(): 409 """Get the hardware address on Unix by running ifconfig.""" 410 # This works on Linux ('' or '-a'), Tru64 ('-av'), but not all Unixes. 411 keywords = (b'hwaddr', b'ether', b'address:', b'lladdr') 412 for args in ('', '-a', '-av'): 413 mac = _find_mac('ifconfig', args, keywords, lambda i: i+1) 414 if mac: 415 return mac 416 return None 417 418def _ip_getnode(): 419 """Get the hardware address on Unix by running ip.""" 420 # This works on Linux with iproute2. 421 mac = _find_mac('ip', 'link', [b'link/ether'], lambda i: i+1) 422 if mac: 423 return mac 424 return None 425 426def _arp_getnode(): 427 """Get the hardware address on Unix by running arp.""" 428 import os, socket 429 try: 430 ip_addr = socket.gethostbyname(socket.gethostname()) 431 except OSError: 432 return None 433 434 # Try getting the MAC addr from arp based on our IP address (Solaris). 435 mac = _find_mac('arp', '-an', [os.fsencode(ip_addr)], lambda i: -1) 436 if mac: 437 return mac 438 439 # This works on OpenBSD 440 mac = _find_mac('arp', '-an', [os.fsencode(ip_addr)], lambda i: i+1) 441 if mac: 442 return mac 443 444 # This works on Linux, FreeBSD and NetBSD 445 mac = _find_mac('arp', '-an', [os.fsencode('(%s)' % ip_addr)], 446 lambda i: i+2) 447 # Return None instead of 0. 448 if mac: 449 return mac 450 return None 451 452def _lanscan_getnode(): 453 """Get the hardware address on Unix by running lanscan.""" 454 # This might work on HP-UX. 455 return _find_mac('lanscan', '-ai', [b'lan0'], lambda i: 0) 456 457def _netstat_getnode(): 458 """Get the hardware address on Unix by running netstat.""" 459 # This might work on AIX, Tru64 UNIX. 460 first_local_mac = None 461 try: 462 proc = _popen('netstat', '-ia') 463 if not proc: 464 return None 465 with proc: 466 words = proc.stdout.readline().rstrip().split() 467 try: 468 i = words.index(b'Address') 469 except ValueError: 470 return None 471 for line in proc.stdout: 472 try: 473 words = line.rstrip().split() 474 word = words[i] 475 if len(word) == 17 and word.count(b':') == 5: 476 mac = int(word.replace(b':', b''), 16) 477 if _is_universal(mac): 478 return mac 479 first_local_mac = first_local_mac or mac 480 except (ValueError, IndexError): 481 pass 482 except OSError: 483 pass 484 return first_local_mac or None 485 486def _ipconfig_getnode(): 487 """Get the hardware address on Windows by running ipconfig.exe.""" 488 import os, re, subprocess 489 first_local_mac = None 490 dirs = ['', r'c:\windows\system32', r'c:\winnt\system32'] 491 try: 492 import ctypes 493 buffer = ctypes.create_string_buffer(300) 494 ctypes.windll.kernel32.GetSystemDirectoryA(buffer, 300) 495 dirs.insert(0, buffer.value.decode('mbcs')) 496 except: 497 pass 498 for dir in dirs: 499 try: 500 proc = subprocess.Popen([os.path.join(dir, 'ipconfig'), '/all'], 501 stdout=subprocess.PIPE, 502 encoding="oem") 503 except OSError: 504 continue 505 with proc: 506 for line in proc.stdout: 507 value = line.split(':')[-1].strip().lower() 508 if re.fullmatch('(?:[0-9a-f][0-9a-f]-){5}[0-9a-f][0-9a-f]', value): 509 mac = int(value.replace('-', ''), 16) 510 if _is_universal(mac): 511 return mac 512 first_local_mac = first_local_mac or mac 513 return first_local_mac or None 514 515def _netbios_getnode(): 516 """Get the hardware address on Windows using NetBIOS calls. 517 See http://support.microsoft.com/kb/118623 for details.""" 518 import win32wnet, netbios 519 first_local_mac = None 520 ncb = netbios.NCB() 521 ncb.Command = netbios.NCBENUM 522 ncb.Buffer = adapters = netbios.LANA_ENUM() 523 adapters._pack() 524 if win32wnet.Netbios(ncb) != 0: 525 return None 526 adapters._unpack() 527 for i in range(adapters.length): 528 ncb.Reset() 529 ncb.Command = netbios.NCBRESET 530 ncb.Lana_num = ord(adapters.lana[i]) 531 if win32wnet.Netbios(ncb) != 0: 532 continue 533 ncb.Reset() 534 ncb.Command = netbios.NCBASTAT 535 ncb.Lana_num = ord(adapters.lana[i]) 536 ncb.Callname = '*'.ljust(16) 537 ncb.Buffer = status = netbios.ADAPTER_STATUS() 538 if win32wnet.Netbios(ncb) != 0: 539 continue 540 status._unpack() 541 bytes = status.adapter_address[:6] 542 if len(bytes) != 6: 543 continue 544 mac = int.from_bytes(bytes, 'big') 545 if _is_universal(mac): 546 return mac 547 first_local_mac = first_local_mac or mac 548 return first_local_mac or None 549 550 551_generate_time_safe = _UuidCreate = None 552_has_uuid_generate_time_safe = None 553 554# Import optional C extension at toplevel, to help disabling it when testing 555try: 556 import _uuid 557except ImportError: 558 _uuid = None 559 560 561def _load_system_functions(): 562 """ 563 Try to load platform-specific functions for generating uuids. 564 """ 565 global _generate_time_safe, _UuidCreate, _has_uuid_generate_time_safe 566 567 if _has_uuid_generate_time_safe is not None: 568 return 569 570 _has_uuid_generate_time_safe = False 571 572 if sys.platform == "darwin" and int(os.uname().release.split('.')[0]) < 9: 573 # The uuid_generate_* functions are broken on MacOS X 10.5, as noted 574 # in issue #8621 the function generates the same sequence of values 575 # in the parent process and all children created using fork (unless 576 # those children use exec as well). 577 # 578 # Assume that the uuid_generate functions are broken from 10.5 onward, 579 # the test can be adjusted when a later version is fixed. 580 pass 581 elif _uuid is not None: 582 _generate_time_safe = _uuid.generate_time_safe 583 _has_uuid_generate_time_safe = _uuid.has_uuid_generate_time_safe 584 return 585 586 try: 587 # If we couldn't find an extension module, try ctypes to find 588 # system routines for UUID generation. 589 # Thanks to Thomas Heller for ctypes and for his help with its use here. 590 import ctypes 591 import ctypes.util 592 593 # The uuid_generate_* routines are provided by libuuid on at least 594 # Linux and FreeBSD, and provided by libc on Mac OS X. 595 _libnames = ['uuid'] 596 if not sys.platform.startswith('win'): 597 _libnames.append('c') 598 for libname in _libnames: 599 try: 600 lib = ctypes.CDLL(ctypes.util.find_library(libname)) 601 except Exception: # pragma: nocover 602 continue 603 # Try to find the safe variety first. 604 if hasattr(lib, 'uuid_generate_time_safe'): 605 _uuid_generate_time_safe = lib.uuid_generate_time_safe 606 # int uuid_generate_time_safe(uuid_t out); 607 def _generate_time_safe(): 608 _buffer = ctypes.create_string_buffer(16) 609 res = _uuid_generate_time_safe(_buffer) 610 return bytes(_buffer.raw), res 611 _has_uuid_generate_time_safe = True 612 break 613 614 elif hasattr(lib, 'uuid_generate_time'): # pragma: nocover 615 _uuid_generate_time = lib.uuid_generate_time 616 # void uuid_generate_time(uuid_t out); 617 _uuid_generate_time.restype = None 618 def _generate_time_safe(): 619 _buffer = ctypes.create_string_buffer(16) 620 _uuid_generate_time(_buffer) 621 return bytes(_buffer.raw), None 622 break 623 624 # On Windows prior to 2000, UuidCreate gives a UUID containing the 625 # hardware address. On Windows 2000 and later, UuidCreate makes a 626 # random UUID and UuidCreateSequential gives a UUID containing the 627 # hardware address. These routines are provided by the RPC runtime. 628 # NOTE: at least on Tim's WinXP Pro SP2 desktop box, while the last 629 # 6 bytes returned by UuidCreateSequential are fixed, they don't appear 630 # to bear any relationship to the MAC address of any network device 631 # on the box. 632 try: 633 lib = ctypes.windll.rpcrt4 634 except: 635 lib = None 636 _UuidCreate = getattr(lib, 'UuidCreateSequential', 637 getattr(lib, 'UuidCreate', None)) 638 639 except Exception as exc: 640 import warnings 641 warnings.warn(f"Could not find fallback ctypes uuid functions: {exc}", 642 ImportWarning) 643 644 645def _unix_getnode(): 646 """Get the hardware address on Unix using the _uuid extension module 647 or ctypes.""" 648 _load_system_functions() 649 uuid_time, _ = _generate_time_safe() 650 return UUID(bytes=uuid_time).node 651 652def _windll_getnode(): 653 """Get the hardware address on Windows using ctypes.""" 654 import ctypes 655 _load_system_functions() 656 _buffer = ctypes.create_string_buffer(16) 657 if _UuidCreate(_buffer) == 0: 658 return UUID(bytes=bytes_(_buffer.raw)).node 659 660def _random_getnode(): 661 """Get a random node ID.""" 662 # RFC 4122, $4.1.6 says "For systems with no IEEE address, a randomly or 663 # pseudo-randomly generated value may be used; see Section 4.5. The 664 # multicast bit must be set in such addresses, in order that they will 665 # never conflict with addresses obtained from network cards." 666 # 667 # The "multicast bit" of a MAC address is defined to be "the least 668 # significant bit of the first octet". This works out to be the 41st bit 669 # counting from 1 being the least significant bit, or 1<<40. 670 # 671 # See https://en.wikipedia.org/wiki/MAC_address#Unicast_vs._multicast 672 import random 673 return random.getrandbits(48) | (1 << 40) 674 675 676_node = None 677 678_NODE_GETTERS_WIN32 = [_windll_getnode, _netbios_getnode, _ipconfig_getnode] 679 680_NODE_GETTERS_UNIX = [_unix_getnode, _ifconfig_getnode, _ip_getnode, 681 _arp_getnode, _lanscan_getnode, _netstat_getnode] 682 683def getnode(*, getters=None): 684 """Get the hardware address as a 48-bit positive integer. 685 686 The first time this runs, it may launch a separate program, which could 687 be quite slow. If all attempts to obtain the hardware address fail, we 688 choose a random 48-bit number with its eighth bit set to 1 as recommended 689 in RFC 4122. 690 """ 691 global _node 692 if _node is not None: 693 return _node 694 695 if sys.platform == 'win32': 696 getters = _NODE_GETTERS_WIN32 697 else: 698 getters = _NODE_GETTERS_UNIX 699 700 for getter in getters + [_random_getnode]: 701 try: 702 _node = getter() 703 except: 704 continue 705 if (_node is not None) and (0 <= _node < (1 << 48)): 706 return _node 707 assert False, '_random_getnode() returned invalid value: {}'.format(_node) 708 709 710_last_timestamp = None 711 712def uuid1(node=None, clock_seq=None): 713 """Generate a UUID from a host ID, sequence number, and the current time. 714 If 'node' is not given, getnode() is used to obtain the hardware 715 address. If 'clock_seq' is given, it is used as the sequence number; 716 otherwise a random 14-bit sequence number is chosen.""" 717 718 # When the system provides a version-1 UUID generator, use it (but don't 719 # use UuidCreate here because its UUIDs don't conform to RFC 4122). 720 _load_system_functions() 721 if _generate_time_safe is not None and node is clock_seq is None: 722 uuid_time, safely_generated = _generate_time_safe() 723 try: 724 is_safe = SafeUUID(safely_generated) 725 except ValueError: 726 is_safe = SafeUUID.unknown 727 return UUID(bytes=uuid_time, is_safe=is_safe) 728 729 global _last_timestamp 730 import time 731 nanoseconds = int(time.time() * 1e9) 732 # 0x01b21dd213814000 is the number of 100-ns intervals between the 733 # UUID epoch 1582-10-15 00:00:00 and the Unix epoch 1970-01-01 00:00:00. 734 timestamp = int(nanoseconds/100) + 0x01b21dd213814000 735 if _last_timestamp is not None and timestamp <= _last_timestamp: 736 timestamp = _last_timestamp + 1 737 _last_timestamp = timestamp 738 if clock_seq is None: 739 import random 740 clock_seq = random.getrandbits(14) # instead of stable storage 741 time_low = timestamp & 0xffffffff 742 time_mid = (timestamp >> 32) & 0xffff 743 time_hi_version = (timestamp >> 48) & 0x0fff 744 clock_seq_low = clock_seq & 0xff 745 clock_seq_hi_variant = (clock_seq >> 8) & 0x3f 746 if node is None: 747 node = getnode() 748 return UUID(fields=(time_low, time_mid, time_hi_version, 749 clock_seq_hi_variant, clock_seq_low, node), version=1) 750 751def uuid3(namespace, name): 752 """Generate a UUID from the MD5 hash of a namespace UUID and a name.""" 753 from hashlib import md5 754 hash = md5(namespace.bytes + bytes(name, "utf-8")).digest() 755 return UUID(bytes=hash[:16], version=3) 756 757def uuid4(): 758 """Generate a random UUID.""" 759 return UUID(bytes=os.urandom(16), version=4) 760 761def uuid5(namespace, name): 762 """Generate a UUID from the SHA-1 hash of a namespace UUID and a name.""" 763 from hashlib import sha1 764 hash = sha1(namespace.bytes + bytes(name, "utf-8")).digest() 765 return UUID(bytes=hash[:16], version=5) 766 767# The following standard UUIDs are for use with uuid3() or uuid5(). 768 769NAMESPACE_DNS = UUID('6ba7b810-9dad-11d1-80b4-00c04fd430c8') 770NAMESPACE_URL = UUID('6ba7b811-9dad-11d1-80b4-00c04fd430c8') 771NAMESPACE_OID = UUID('6ba7b812-9dad-11d1-80b4-00c04fd430c8') 772NAMESPACE_X500 = UUID('6ba7b814-9dad-11d1-80b4-00c04fd430c8') 773