uuid 生成算法
uuid | Dart Package https://pub.dev/packages/uuid
uuid --- RFC 4122 定义的UUID对象 — Python 3.10.11 文档 https://docs.python.org/zh-cn/3.10/library/uuid.html
uuid --- RFC 4122 定义的UUID对象
源代码： Lib/uuid.py
这个模块提供了不可变的 UUID 对象 (UUID 类) 和 uuid1(), uuid3(), uuid4(), uuid5() 等函数用于生成 RFC 4122 所定义的第 1, 3, 4 和 5 版 UUID。
如果你想要的只是一个唯一的ID，你可能应该调用 uuid1() 或 uuid4()。 注意 uuid1() 可能会损害隐私，因为它创建了一个包含计算机网络地址的UUID。 uuid4() 可以创建一个随机UUID。
根据底层平台的支持，uuid1() 可能会也可能不会返回一个 "安全的" UUID。 安全的 UUID 是使用同步方法生成的，确保没有两个进程可以获得相同的 UUID。 所有 UUID 的实例都有一个 is_safe 属性，使用这个枚举来传递关于 UUID 安全的任何信息:
- class
uuid.SafeUUID -
3.7 新版功能.
safe-
该UUID是由平台以多进程安全的方式生成的。
unsafe-
UUID不是以多进程安全的方式生成的。
unknown-
该平台不提供UUID是否安全生成的信息。
- class
uuid.UUID(hex=None, bytes=None, bytes_le=None, fields=None, int=None, version=None, *, is_safe=SafeUUID.unknown) -
用一串32位十六进制数字、一串大端序16个字节作为*bytes*参数、一串16个小端序字节作为*bytes_le*参数、一个由六个整数组成的元组（32位*time_low*，16位*time_mid*，16位*time_hi_version*，8位*clock_seq_hi_variant*，8位*clock_seq_low*，48位*node*）作为*fields*参数，或者一个128位整数作为*int*参数创建一个UUID。当给出一串十六进制数字时，大括号、连字符和URN前缀都是可选的。 例如，这些表达式都产生相同的UUID:
UUID('{12345678-1234-5678-1234-567812345678}') UUID('12345678123456781234567812345678') UUID('urn:uuid:12345678-1234-5678-1234-567812345678') UUID(bytes=b'\x12\x34\x56\x78'*4) UUID(bytes_le=b'\x78\x56\x34\x12\x34\x12\x78\x56' + b'\x12\x34\x56\x78\x12\x34\x56\x78') UUID(fields=(0x12345678, 0x1234, 0x5678, 0x12, 0x34, 0x567812345678)) UUID(int=0x12345678123456781234567812345678)
必须给出 hex、bytes、bytes_le、fields 或 int 中的唯一一个。 version 参数是可选的；如果给定，产生的UUID将根据 RFC 4122 设置其变体和版本号，覆盖给定的 hex、bytes、bytes_le、fields 或 int 中的位。
UUID 对象的比较是通过比较它们的
UUID.int属性进行的。 与非 UUID 对象的比较会引发TypeError。str(uuid)返回一个12345678-1234-5678-1234-567812345678形式的字符串，其中 32 位十六进制数字代表 UUID。
UUID 实例有这些只读的属性:
UUID.bytes-
UUID是一个16字节的字符串（包含6个大端字节序的整数字段）。
UUID.bytes_le-
UUID 是一个 16 字节的字符串（其中 time_low、time_mid 和 time_hi_version 为小端字节顺序）。
UUID.fields-
以元组形式存放的UUID的6个整数域，有六个单独的属性和两个派生属性：
域
含意
time_lowUUID的前32位
time_mid接前一域的16位
time_hi_version接前一域的16位
clock_seq_hi_variant接前一域的8位
clock_seq_low接前一域的8位
nodeUUID的最后48位
UUID的总长60位的时间戳
clock_seq14位的序列号
UUID.hex-
UUID 是一个 32 字符的小写十六进制数码字符串。
UUID.int-
UUID是一个128位的整数。
UUID.urn-
在 RFC 4122 中定义的 URN 形式的 UUID。
UUID.variant-
UUID 的变体，它决定了 UUID 的内部布局。 这将是
RESERVED_NCS,RFC_4122,RESERVED_MICROSOFT或RESERVED_FUTURE中的一个。
UUID.version-
UUID 版本号（1 到 5，只有当变体为
RFC_4122时才有意义）。
UUID.is_safe-
一个
SafeUUID的枚举，表示平台是否以多进程安全的方式生成 UUID。3.7 新版功能.
uuid 模块定义了以下函数：
uuid.getnode()-
获取 48 位正整数形式的硬件地址。 第一次运行时，它可能会启动一个单独的程序，这可能会相当慢。 如果所有获取硬件地址的尝试都失败了，我们会按照 RFC 4122 中的建议，选择一个随机的 48 位数字，其多播位 (第一个八进制数的最小有效位) 设置为 1。 “硬件地址”是指一个网络接口的 MAC 地址。 在一台有多个网络接口的机器上，普遍管理的 MAC 地址 (即第一个八位数的第二个最小有效位是 未设置的) 将比本地管理的 MAC 地址优先，但没有其他排序保证。
在 3.7 版更改: 普遍管理的MAC地址优于本地管理的MAC地址，因为前者保证是全球唯一的，而后者则不是。
uuid.uuid1(node=None, clock_seq=None)-
根据主机 ID、序列号和当前时间生成一个 UUID。 如果没有给出 node，则使用
getnode()来获取硬件地址。 如果给出了 clock_seq，它将被用作序列号；否则将选择一个随机的 14 比特位序列号。
uuid.uuid3(namespace, name)-
根据命名空间标识符（这是一个UUID）和名称（这是一个字符串）的MD5哈希值，生成一个UUID。
uuid.uuid4()-
生成一个随机的UUID。
uuid.uuid5(namespace, name)-
根据命名空间标识符（这是一个UUID）和名称（这是一个字符串）的SHA-1哈希值生成一个UUID。
uuid 模块定义了以下命名空间标识符，供 uuid3() 或 uuid5() 使用。
uuid.NAMESPACE_DNS-
When this namespace is specified, the name string is a fully qualified domain name.
uuid.NAMESPACE_URL-
当指定这个命名空间时，name 字符串是一个 URL。
uuid.NAMESPACE_OID-
当指定这个命名空间时，name 字符串是一个 ISO OID。
uuid.NAMESPACE_X500-
当指定这个命名空间时，name 字符串是 DER 或文本输出格式的 X.500 DN。
uuid 模块为 variant 属性的可能值定义了以下常量:
uuid.RESERVED_NCS-
为NCS兼容性保留。
uuid.RFC_4122-
指定 RFC 4122 中给出的 UUID 布局。
uuid.RESERVED_MICROSOFT-
为微软的兼容性保留。
uuid.RESERVED_FUTURE-
保留给未来的定义。
参见
- RFC 4122 - 通用唯一标识符（UUID）URN命名空间
-
本规范定义了UUID的统一资源名称空间，UUID的内部格式，以及生成UUID的方法。
r"""UUID objects (universally unique identifiers) according to RFC 4122.
This module provides immutable UUID objects (class UUID) and the functions
uuid1(), uuid3(), uuid4(), uuid5() for generating version 1, 3, 4, and 5
UUIDs as specified in RFC 4122.
If all you want is a unique ID, you should probably call uuid1() or uuid4().
Note that uuid1() may compromise privacy since it creates a UUID containing
the computer's network address. uuid4() creates a random UUID.
Typical usage:
>>> import uuid
# make a UUID based on the host ID and current time
>>> uuid.uuid1() # doctest: +SKIP
UUID('a8098c1a-f86e-11da-bd1a-00112444be1e')
# make a UUID using an MD5 hash of a namespace UUID and a name
>>> uuid.uuid3(uuid.NAMESPACE_DNS, 'python.org')
UUID('6fa459ea-ee8a-3ca4-894e-db77e160355e')
# make a random UUID
>>> uuid.uuid4() # doctest: +SKIP
UUID('16fd2706-8baf-433b-82eb-8c7fada847da')
# make a UUID using a SHA-1 hash of a namespace UUID and a name
>>> uuid.uuid5(uuid.NAMESPACE_DNS, 'python.org')
UUID('886313e1-3b8a-5372-9b90-0c9aee199e5d')
# make a UUID from a string of hex digits (braces and hyphens ignored)
>>> x = uuid.UUID('{00010203-0405-0607-0809-0a0b0c0d0e0f}')
# convert a UUID to a string of hex digits in standard form
>>> str(x)
'00010203-0405-0607-0809-0a0b0c0d0e0f'
# get the raw 16 bytes of the UUID
>>> x.bytes
b'\x00\x01\x02\x03\x04\x05\x06\x07\x08\t\n\x0b\x0c\r\x0e\x0f'
# make a UUID from a 16-byte string
>>> uuid.UUID(bytes=x.bytes)
UUID('00010203-0405-0607-0809-0a0b0c0d0e0f')
"""
import os
import sys
from enum import Enum
__author__ = 'Ka-Ping Yee <ping@zesty.ca>'
# The recognized platforms - known behaviors
if sys.platform in ('win32', 'darwin'):
_AIX = _LINUX = False
else:
import platform
_platform_system = platform.system()
_AIX = _platform_system == 'AIX'
_LINUX = _platform_system == 'Linux'
_MAC_DELIM = b':'
_MAC_OMITS_LEADING_ZEROES = False
if _AIX:
_MAC_DELIM = b'.'
_MAC_OMITS_LEADING_ZEROES = True
RESERVED_NCS, RFC_4122, RESERVED_MICROSOFT, RESERVED_FUTURE = [
'reserved for NCS compatibility', 'specified in RFC 4122',
'reserved for Microsoft compatibility', 'reserved for future definition']
int_ = int # The built-in int type
bytes_ = bytes # The built-in bytes type
class SafeUUID(Enum):
safe = 0
unsafe = -1
unknown = None
class UUID:
"""Instances of the UUID class represent UUIDs as specified in RFC 4122.
UUID objects are immutable, hashable, and usable as dictionary keys.
Converting a UUID to a string with str() yields something in the form
'12345678-1234-1234-1234-123456789abc'. The UUID constructor accepts
five possible forms: a similar string of hexadecimal digits, or a tuple
of six integer fields (with 32-bit, 16-bit, 16-bit, 8-bit, 8-bit, and
48-bit values respectively) as an argument named 'fields', or a string
of 16 bytes (with all the integer fields in big-endian order) as an
argument named 'bytes', or a string of 16 bytes (with the first three
fields in little-endian order) as an argument named 'bytes_le', or a
single 128-bit integer as an argument named 'int'.
UUIDs have these read-only attributes:
bytes the UUID as a 16-byte string (containing the six
integer fields in big-endian byte order)
bytes_le the UUID as a 16-byte string (with time_low, time_mid,
and time_hi_version in little-endian byte order)
fields a tuple of the six integer fields of the UUID,
which are also available as six individual attributes
and two derived attributes:
time_low the first 32 bits of the UUID
time_mid the next 16 bits of the UUID
time_hi_version the next 16 bits of the UUID
clock_seq_hi_variant the next 8 bits of the UUID
clock_seq_low the next 8 bits of the UUID
node the last 48 bits of the UUID
time the 60-bit timestamp
clock_seq the 14-bit sequence number
hex the UUID as a 32-character hexadecimal string
int the UUID as a 128-bit integer
urn the UUID as a URN as specified in RFC 4122
variant the UUID variant (one of the constants RESERVED_NCS,
RFC_4122, RESERVED_MICROSOFT, or RESERVED_FUTURE)
version the UUID version number (1 through 5, meaningful only
when the variant is RFC_4122)
is_safe An enum indicating whether the UUID has been generated in
a way that is safe for multiprocessing applications, via
uuid_generate_time_safe(3).
"""
__slots__ = ('int', 'is_safe', '__weakref__')
def __init__(self, hex=None, bytes=None, bytes_le=None, fields=None,
int=None, version=None,
*, is_safe=SafeUUID.unknown):
r"""Create a UUID from either a string of 32 hexadecimal digits,
a string of 16 bytes as the 'bytes' argument, a string of 16 bytes
in little-endian order as the 'bytes_le' argument, a tuple of six
integers (32-bit time_low, 16-bit time_mid, 16-bit time_hi_version,
8-bit clock_seq_hi_variant, 8-bit clock_seq_low, 48-bit node) as
the 'fields' argument, or a single 128-bit integer as the 'int'
argument. When a string of hex digits is given, curly braces,
hyphens, and a URN prefix are all optional. For example, these
expressions all yield the same UUID:
UUID('{12345678-1234-5678-1234-567812345678}')
UUID('12345678123456781234567812345678')
UUID('urn:uuid:12345678-1234-5678-1234-567812345678')
UUID(bytes='\x12\x34\x56\x78'*4)
UUID(bytes_le='\x78\x56\x34\x12\x34\x12\x78\x56' +
'\x12\x34\x56\x78\x12\x34\x56\x78')
UUID(fields=(0x12345678, 0x1234, 0x5678, 0x12, 0x34, 0x567812345678))
UUID(int=0x12345678123456781234567812345678)
Exactly one of 'hex', 'bytes', 'bytes_le', 'fields', or 'int' must
be given. The 'version' argument is optional; if given, the resulting
UUID will have its variant and version set according to RFC 4122,
overriding the given 'hex', 'bytes', 'bytes_le', 'fields', or 'int'.
is_safe is an enum exposed as an attribute on the instance. It
indicates whether the UUID has been generated in a way that is safe
for multiprocessing applications, via uuid_generate_time_safe(3).
"""
if [hex, bytes, bytes_le, fields, int].count(None) != 4:
raise TypeError('one of the hex, bytes, bytes_le, fields, '
'or int arguments must be given')
if hex is not None:
hex = hex.replace('urn:', '').replace('uuid:', '')
hex = hex.strip('{}').replace('-', '')
if len(hex) != 32:
raise ValueError('badly formed hexadecimal UUID string')
int = int_(hex, 16)
if bytes_le is not None:
if len(bytes_le) != 16:
raise ValueError('bytes_le is not a 16-char string')
bytes = (bytes_le[4-1::-1] + bytes_le[6-1:4-1:-1] +
bytes_le[8-1:6-1:-1] + bytes_le[8:])
if bytes is not None:
if len(bytes) != 16:
raise ValueError('bytes is not a 16-char string')
assert isinstance(bytes, bytes_), repr(bytes)
int = int_.from_bytes(bytes, byteorder='big')
if fields is not None:
if len(fields) != 6:
raise ValueError('fields is not a 6-tuple')
(time_low, time_mid, time_hi_version,
clock_seq_hi_variant, clock_seq_low, node) = fields
if not 0 <= time_low < 1<<32:
raise ValueError('field 1 out of range (need a 32-bit value)')
if not 0 <= time_mid < 1<<16:
raise ValueError('field 2 out of range (need a 16-bit value)')
if not 0 <= time_hi_version < 1<<16:
raise ValueError('field 3 out of range (need a 16-bit value)')
if not 0 <= clock_seq_hi_variant < 1<<8:
raise ValueError('field 4 out of range (need an 8-bit value)')
if not 0 <= clock_seq_low < 1<<8:
raise ValueError('field 5 out of range (need an 8-bit value)')
if not 0 <= node < 1<<48:
raise ValueError('field 6 out of range (need a 48-bit value)')
clock_seq = (clock_seq_hi_variant << 8) | clock_seq_low
int = ((time_low << 96) | (time_mid << 80) |
(time_hi_version << 64) | (clock_seq << 48) | node)
if int is not None:
if not 0 <= int < 1<<128:
raise ValueError('int is out of range (need a 128-bit value)')
if version is not None:
if not 1 <= version <= 5:
raise ValueError('illegal version number')
# Set the variant to RFC 4122.
int &= ~(0xc000 << 48)
int |= 0x8000 << 48
# Set the version number.
int &= ~(0xf000 << 64)
int |= version << 76
object.__setattr__(self, 'int', int)
object.__setattr__(self, 'is_safe', is_safe)
def __getstate__(self):
d = {'int': self.int}
if self.is_safe != SafeUUID.unknown:
# is_safe is a SafeUUID instance. Return just its value, so that
# it can be un-pickled in older Python versions without SafeUUID.
d['is_safe'] = self.is_safe.value
return d
def __setstate__(self, state):
object.__setattr__(self, 'int', state['int'])
# is_safe was added in 3.7; it is also omitted when it is "unknown"
object.__setattr__(self, 'is_safe',
SafeUUID(state['is_safe'])
if 'is_safe' in state else SafeUUID.unknown)
def __eq__(self, other):
if isinstance(other, UUID):
return self.int == other.int
return NotImplemented
# Q. What's the value of being able to sort UUIDs?
# A. Use them as keys in a B-Tree or similar mapping.
def __lt__(self, other):
if isinstance(other, UUID):
return self.int < other.int
return NotImplemented
def __gt__(self, other):
if isinstance(other, UUID):
return self.int > other.int
return NotImplemented
def __le__(self, other):
if isinstance(other, UUID):
return self.int <= other.int
return NotImplemented
def __ge__(self, other):
if isinstance(other, UUID):
return self.int >= other.int
return NotImplemented
def __hash__(self):
return hash(self.int)
def __int__(self):
return self.int
def __repr__(self):
return '%s(%r)' % (self.__class__.__name__, str(self))
def __setattr__(self, name, value):
raise TypeError('UUID objects are immutable')
def __str__(self):
hex = '%032x' % self.int
return '%s-%s-%s-%s-%s' % (
hex[:8], hex[8:12], hex[12:16], hex[16:20], hex[20:])
@property
def bytes(self):
return self.int.to_bytes(16, 'big')
@property
def bytes_le(self):
bytes = self.bytes
return (bytes[4-1::-1] + bytes[6-1:4-1:-1] + bytes[8-1:6-1:-1] +
bytes[8:])
@property
def fields(self):
return (self.time_low, self.time_mid, self.time_hi_version,
self.clock_seq_hi_variant, self.clock_seq_low, self.node)
@property
def time_low(self):
return self.int >> 96
@property
def time_mid(self):
return (self.int >> 80) & 0xffff
@property
def time_hi_version(self):
return (self.int >> 64) & 0xffff
@property
def clock_seq_hi_variant(self):
return (self.int >> 56) & 0xff
@property
def clock_seq_low(self):
return (self.int >> 48) & 0xff
@property
def time(self):
return (((self.time_hi_version & 0x0fff) << 48) |
(self.time_mid << 32) | self.time_low)
@property
def clock_seq(self):
return (((self.clock_seq_hi_variant & 0x3f) << 8) |
self.clock_seq_low)
@property
def node(self):
return self.int & 0xffffffffffff
@property
def hex(self):
return '%032x' % self.int
@property
def urn(self):
return 'urn:uuid:' + str(self)
@property
def variant(self):
if not self.int & (0x8000 << 48):
return RESERVED_NCS
elif not self.int & (0x4000 << 48):
return RFC_4122
elif not self.int & (0x2000 << 48):
return RESERVED_MICROSOFT
else:
return RESERVED_FUTURE
@property
def version(self):
# The version bits are only meaningful for RFC 4122 UUIDs.
if self.variant == RFC_4122:
return int((self.int >> 76) & 0xf)
def _get_command_stdout(command, *args):
import io, os, shutil, subprocess
try:
path_dirs = os.environ.get('PATH', os.defpath).split(os.pathsep)
path_dirs.extend(['/sbin', '/usr/sbin'])
executable = shutil.which(command, path=os.pathsep.join(path_dirs))
if executable is None:
return None
# LC_ALL=C to ensure English output, stderr=DEVNULL to prevent output
# on stderr (Note: we don't have an example where the words we search
# for are actually localized, but in theory some system could do so.)
env = dict(os.environ)
env['LC_ALL'] = 'C'
# Empty strings will be quoted by popen so we should just ommit it
if args != ('',):
command = (executable, *args)
else:
command = (executable,)
proc = subprocess.Popen(command,
stdout=subprocess.PIPE,
stderr=subprocess.DEVNULL,
env=env)
if not proc:
return None
stdout, stderr = proc.communicate()
return io.BytesIO(stdout)
except (OSError, subprocess.SubprocessError):
return None
# For MAC (a.k.a. IEEE 802, or EUI-48) addresses, the second least significant
# bit of the first octet signifies whether the MAC address is universally (0)
# or locally (1) administered. Network cards from hardware manufacturers will
# always be universally administered to guarantee global uniqueness of the MAC
# address, but any particular machine may have other interfaces which are
# locally administered. An example of the latter is the bridge interface to
# the Touch Bar on MacBook Pros.
#
# This bit works out to be the 42nd bit counting from 1 being the least
# significant, or 1<<41. We'll prefer universally administered MAC addresses
# over locally administered ones since the former are globally unique, but
# we'll return the first of the latter found if that's all the machine has.
#
# See https://en.wikipedia.org/wiki/MAC_address#Universal_vs._local
def _is_universal(mac):
return not (mac & (1 << 41))
def _find_mac_near_keyword(command, args, keywords, get_word_index):
"""Searches a command's output for a MAC address near a keyword.
Each line of words in the output is case-insensitively searched for
any of the given keywords. Upon a match, get_word_index is invoked
to pick a word from the line, given the index of the match. For
example, lambda i: 0 would get the first word on the line, while
lambda i: i - 1 would get the word preceding the keyword.
"""
stdout = _get_command_stdout(command, args)
if stdout is None:
return None
first_local_mac = None
for line in stdout:
words = line.lower().rstrip().split()
for i in range(len(words)):
if words[i] in keywords:
try:
word = words[get_word_index(i)]
mac = int(word.replace(_MAC_DELIM, b''), 16)
except (ValueError, IndexError):
# Virtual interfaces, such as those provided by
# VPNs, do not have a colon-delimited MAC address
# as expected, but a 16-byte HWAddr separated by
# dashes. These should be ignored in favor of a
# real MAC address
pass
else:
if _is_universal(mac):
return mac
first_local_mac = first_local_mac or mac
return first_local_mac or None
def _parse_mac(word):
# Accept 'HH:HH:HH:HH:HH:HH' MAC address (ex: '52:54:00:9d:0e:67'),
# but reject IPv6 address (ex: 'fe80::5054:ff:fe9' or '123:2:3:4:5:6:7:8').
#
# Virtual interfaces, such as those provided by VPNs, do not have a
# colon-delimited MAC address as expected, but a 16-byte HWAddr separated
# by dashes. These should be ignored in favor of a real MAC address
parts = word.split(_MAC_DELIM)
if len(parts) != 6:
return
if _MAC_OMITS_LEADING_ZEROES:
# (Only) on AIX the macaddr value given is not prefixed by 0, e.g.
# en0 1500 link#2 fa.bc.de.f7.62.4 110854824 0 160133733 0 0
# not
# en0 1500 link#2 fa.bc.de.f7.62.04 110854824 0 160133733 0 0
if not all(1 <= len(part) <= 2 for part in parts):
return
hexstr = b''.join(part.rjust(2, b'0') for part in parts)
else:
if not all(len(part) == 2 for part in parts):
return
hexstr = b''.join(parts)
try:
return int(hexstr, 16)
except ValueError:
return
def _find_mac_under_heading(command, args, heading):
"""Looks for a MAC address under a heading in a command's output.
The first line of words in the output is searched for the given
heading. Words at the same word index as the heading in subsequent
lines are then examined to see if they look like MAC addresses.
"""
stdout = _get_command_stdout(command, args)
if stdout is None:
return None
keywords = stdout.readline().rstrip().split()
try:
column_index = keywords.index(heading)
except ValueError:
return None
first_local_mac = None
for line in stdout:
words = line.rstrip().split()
try:
word = words[column_index]
except IndexError:
continue
mac = _parse_mac(word)
if mac is None:
continue
if _is_universal(mac):
return mac
if first_local_mac is None:
first_local_mac = mac
return first_local_mac
# The following functions call external programs to 'get' a macaddr value to
# be used as basis for an uuid
def _ifconfig_getnode():
"""Get the hardware address on Unix by running ifconfig."""
# This works on Linux ('' or '-a'), Tru64 ('-av'), but not all Unixes.
keywords = (b'hwaddr', b'ether', b'address:', b'lladdr')
for args in ('', '-a', '-av'):
mac = _find_mac_near_keyword('ifconfig', args, keywords, lambda i: i+1)
if mac:
return mac
return None
def _ip_getnode():
"""Get the hardware address on Unix by running ip."""
# This works on Linux with iproute2.
mac = _find_mac_near_keyword('ip', 'link', [b'link/ether'], lambda i: i+1)
if mac:
return mac
return None
def _arp_getnode():
"""Get the hardware address on Unix by running arp."""
import os, socket
try:
ip_addr = socket.gethostbyname(socket.gethostname())
except OSError:
return None
# Try getting the MAC addr from arp based on our IP address (Solaris).
mac = _find_mac_near_keyword('arp', '-an', [os.fsencode(ip_addr)], lambda i: -1)
if mac:
return mac
# This works on OpenBSD
mac = _find_mac_near_keyword('arp', '-an', [os.fsencode(ip_addr)], lambda i: i+1)
if mac:
return mac
# This works on Linux, FreeBSD and NetBSD
mac = _find_mac_near_keyword('arp', '-an', [os.fsencode('(%s)' % ip_addr)],
lambda i: i+2)
# Return None instead of 0.
if mac:
return mac
return None
def _lanscan_getnode():
"""Get the hardware address on Unix by running lanscan."""
# This might work on HP-UX.
return _find_mac_near_keyword('lanscan', '-ai', [b'lan0'], lambda i: 0)
def _netstat_getnode():
"""Get the hardware address on Unix by running netstat."""
# This works on AIX and might work on Tru64 UNIX.
return _find_mac_under_heading('netstat', '-ian', b'Address')
def _ipconfig_getnode():
"""[DEPRECATED] Get the hardware address on Windows."""
# bpo-40501: UuidCreateSequential() is now the only supported approach
return _windll_getnode()
def _netbios_getnode():
"""[DEPRECATED] Get the hardware address on Windows."""
# bpo-40501: UuidCreateSequential() is now the only supported approach
return _windll_getnode()
# Import optional C extension at toplevel, to help disabling it when testing
try:
import _uuid
_generate_time_safe = getattr(_uuid, "generate_time_safe", None)
_UuidCreate = getattr(_uuid, "UuidCreate", None)
_has_uuid_generate_time_safe = _uuid.has_uuid_generate_time_safe
except ImportError:
_uuid = None
_generate_time_safe = None
_UuidCreate = None
_has_uuid_generate_time_safe = None
def _load_system_functions():
"""[DEPRECATED] Platform-specific functions loaded at import time"""
def _unix_getnode():
"""Get the hardware address on Unix using the _uuid extension module."""
if _generate_time_safe:
uuid_time, _ = _generate_time_safe()
return UUID(bytes=uuid_time).node
def _windll_getnode():
"""Get the hardware address on Windows using the _uuid extension module."""
if _UuidCreate:
uuid_bytes = _UuidCreate()
return UUID(bytes_le=uuid_bytes).node
def _random_getnode():
"""Get a random node ID."""
# RFC 4122, $4.1.6 says "For systems with no IEEE address, a randomly or
# pseudo-randomly generated value may be used; see Section 4.5. The
# multicast bit must be set in such addresses, in order that they will
# never conflict with addresses obtained from network cards."
#
# The "multicast bit" of a MAC address is defined to be "the least
# significant bit of the first octet". This works out to be the 41st bit
# counting from 1 being the least significant bit, or 1<<40.
#
# See https://en.wikipedia.org/wiki/MAC_address#Unicast_vs._multicast
import random
return random.getrandbits(48) | (1 << 40)
# _OS_GETTERS, when known, are targeted for a specific OS or platform.
# The order is by 'common practice' on the specified platform.
# Note: 'posix' and 'windows' _OS_GETTERS are prefixed by a dll/dlload() method
# which, when successful, means none of these "external" methods are called.
# _GETTERS is (also) used by test_uuid.py to SkipUnless(), e.g.,
# @unittest.skipUnless(_uuid._ifconfig_getnode in _uuid._GETTERS, ...)
if _LINUX:
_OS_GETTERS = [_ip_getnode, _ifconfig_getnode]
elif sys.platform == 'darwin':
_OS_GETTERS = [_ifconfig_getnode, _arp_getnode, _netstat_getnode]
elif sys.platform == 'win32':
# bpo-40201: _windll_getnode will always succeed, so these are not needed
_OS_GETTERS = []
elif _AIX:
_OS_GETTERS = [_netstat_getnode]
else:
_OS_GETTERS = [_ifconfig_getnode, _ip_getnode, _arp_getnode,
_netstat_getnode, _lanscan_getnode]
if os.name == 'posix':
_GETTERS = [_unix_getnode] + _OS_GETTERS
elif os.name == 'nt':
_GETTERS = [_windll_getnode] + _OS_GETTERS
else:
_GETTERS = _OS_GETTERS
_node = None
def getnode():
"""Get the hardware address as a 48-bit positive integer.
The first time this runs, it may launch a separate program, which could
be quite slow. If all attempts to obtain the hardware address fail, we
choose a random 48-bit number with its eighth bit set to 1 as recommended
in RFC 4122.
"""
global _node
if _node is not None:
return _node
for getter in _GETTERS + [_random_getnode]:
try:
_node = getter()
except:
continue
if (_node is not None) and (0 <= _node < (1 << 48)):
return _node
assert False, '_random_getnode() returned invalid value: {}'.format(_node)
_last_timestamp = None
def uuid1(node=None, clock_seq=None):
"""Generate a UUID from a host ID, sequence number, and the current time.
If 'node' is not given, getnode() is used to obtain the hardware
address. If 'clock_seq' is given, it is used as the sequence number;
otherwise a random 14-bit sequence number is chosen."""
# When the system provides a version-1 UUID generator, use it (but don't
# use UuidCreate here because its UUIDs don't conform to RFC 4122).
if _generate_time_safe is not None and node is clock_seq is None:
uuid_time, safely_generated = _generate_time_safe()
try:
is_safe = SafeUUID(safely_generated)
except ValueError:
is_safe = SafeUUID.unknown
return UUID(bytes=uuid_time, is_safe=is_safe)
global _last_timestamp
import time
nanoseconds = time.time_ns()
# 0x01b21dd213814000 is the number of 100-ns intervals between the
# UUID epoch 1582-10-15 00:00:00 and the Unix epoch 1970-01-01 00:00:00.
timestamp = nanoseconds // 100 + 0x01b21dd213814000
if _last_timestamp is not None and timestamp <= _last_timestamp:
timestamp = _last_timestamp + 1
_last_timestamp = timestamp
if clock_seq is None:
import random
clock_seq = random.getrandbits(14) # instead of stable storage
time_low = timestamp & 0xffffffff
time_mid = (timestamp >> 32) & 0xffff
time_hi_version = (timestamp >> 48) & 0x0fff
clock_seq_low = clock_seq & 0xff
clock_seq_hi_variant = (clock_seq >> 8) & 0x3f
if node is None:
node = getnode()
return UUID(fields=(time_low, time_mid, time_hi_version,
clock_seq_hi_variant, clock_seq_low, node), version=1)
def uuid3(namespace, name):
"""Generate a UUID from the MD5 hash of a namespace UUID and a name."""
from hashlib import md5
digest = md5(
namespace.bytes + bytes(name, "utf-8"),
usedforsecurity=False
).digest()
return UUID(bytes=digest[:16], version=3)
def uuid4():
"""Generate a random UUID."""
return UUID(bytes=os.urandom(16), version=4)
def uuid5(namespace, name):
"""Generate a UUID from the SHA-1 hash of a namespace UUID and a name."""
from hashlib import sha1
hash = sha1(namespace.bytes + bytes(name, "utf-8")).digest()
return UUID(bytes=hash[:16], version=5)
# The following standard UUIDs are for use with uuid3() or uuid5().
NAMESPACE_DNS = UUID('6ba7b810-9dad-11d1-80b4-00c04fd430c8')
NAMESPACE_URL = UUID('6ba7b811-9dad-11d1-80b4-00c04fd430c8')
NAMESPACE_OID = UUID('6ba7b812-9dad-11d1-80b4-00c04fd430c8')
NAMESPACE_X500 = UUID('6ba7b814-9dad-11d1-80b4-00c04fd430c8')
