text: #!/usr/bin/env python3
  
  """ This module tries to retrieve as much platform-identifying data as
      possible. It makes this information available via function APIs.
  
      If called from the command line, it prints the platform
      information concatenated as single string to stdout. The output
      format is useable as part of a filename.
  
  """
  #    This module is maintained by Marc-Andre Lemburg <mal@egenix.com>.
  #    If you find problems, please submit bug reports/patches via the
  #    Python bug tracker (http://bugs.python.org) and assign them to "lemburg".
  #
  #    Still needed:
  #    * more support for WinCE
  #    * support for MS-DOS (PythonDX ?)
  #    * support for Amiga and other still unsupported platforms running Python
  #    * support for additional Linux distributions
  #
  #    Many thanks to all those who helped adding platform-specific
  #    checks (in no particular order):
  #
  #      Charles G Waldman, David Arnold, Gordon McMillan, Ben Darnell,
  #      Jeff Bauer, Cliff Crawford, Ivan Van Laningham, Josef
  #      Betancourt, Randall Hopper, Karl Putland, John Farrell, Greg
  #      Andruk, Just van Rossum, Thomas Heller, Mark R. Levinson, Mark
  #      Hammond, Bill Tutt, Hans Nowak, Uwe Zessin (OpenVMS support),
  #      Colin Kong, Trent Mick, Guido van Rossum, Anthony Baxter, Steve
  #      Dower
  #
  #    History:
  #
  #    <see CVS and SVN checkin messages for history>
  #
  #    1.0.8 - changed Windows support to read version from kernel32.dll
  #    1.0.7 - added DEV_NULL
  #    1.0.6 - added linux_distribution()
  #    1.0.5 - fixed Java support to allow running the module on Jython
  #    1.0.4 - added IronPython support
  #    1.0.3 - added normalization of Windows system name
  #    1.0.2 - added more Windows support
  #    1.0.1 - reformatted to make doc.py happy
  #    1.0.0 - reformatted a bit and checked into Python CVS
  #    0.8.0 - added sys.version parser and various new access
  #            APIs (python_version(), python_compiler(), etc.)
  #    0.7.2 - fixed architecture() to use sizeof(pointer) where available
  #    0.7.1 - added support for Caldera OpenLinux
  #    0.7.0 - some fixes for WinCE; untabified the source file
  #    0.6.2 - support for OpenVMS - requires version 1.5.2-V006 or higher and
  #            vms_lib.getsyi() configured
  #    0.6.1 - added code to prevent 'uname -p' on platforms which are
  #            known not to support it
  #    0.6.0 - fixed win32_ver() to hopefully work on Win95,98,NT and Win2k;
  #            did some cleanup of the interfaces - some APIs have changed
  #    0.5.5 - fixed another type in the MacOS code... should have
  #            used more coffee today ;-)
  #    0.5.4 - fixed a few typos in the MacOS code
  #    0.5.3 - added experimental MacOS support; added better popen()
  #            workarounds in _syscmd_ver() -- still not 100% elegant
  #            though
  #    0.5.2 - fixed uname() to return '' instead of 'unknown' in all
  #            return values (the system uname command tends to return
  #            'unknown' instead of just leaving the field emtpy)
  #    0.5.1 - included code for slackware dist; added exception handlers
  #            to cover up situations where platforms don't have os.popen
  #            (e.g. Mac) or fail on socket.gethostname(); fixed libc
  #            detection RE
  #    0.5.0 - changed the API names referring to system commands to *syscmd*;
  #            added java_ver(); made syscmd_ver() a private
  #            API (was system_ver() in previous versions) -- use uname()
  #            instead; extended the win32_ver() to also return processor
  #            type information
  #    0.4.0 - added win32_ver() and modified the platform() output for WinXX
  #    0.3.4 - fixed a bug in _follow_symlinks()
  #    0.3.3 - fixed popen() and "file" command invokation bugs
  #    0.3.2 - added architecture() API and support for it in platform()
  #    0.3.1 - fixed syscmd_ver() RE to support Windows NT
  #    0.3.0 - added system alias support
  #    0.2.3 - removed 'wince' again... oh well.
  #    0.2.2 - added 'wince' to syscmd_ver() supported platforms
  #    0.2.1 - added cache logic and changed the platform string format
  #    0.2.0 - changed the API to use functions instead of module globals
  #            since some action take too long to be run on module import
  #    0.1.0 - first release
  #
  #    You can always get the latest version of this module at:
  #
  #             http://www.egenix.com/files/python/platform.py
  #
  #    If that URL should fail, try contacting the author.
  
  __copyright__ = """
      Copyright (c) 1999-2000, Marc-Andre Lemburg; mailto:mal@lemburg.com
      Copyright (c) 2000-2010, eGenix.com Software GmbH; mailto:info@egenix.com
  
      Permission to use, copy, modify, and distribute this software and its
      documentation for any purpose and without fee or royalty is hereby granted,
      provided that the above copyright notice appear in all copies and that
      both that copyright notice and this permission notice appear in
      supporting documentation or portions thereof, including modifications,
      that you make.
  
      EGENIX.COM SOFTWARE GMBH DISCLAIMS ALL WARRANTIES WITH REGARD TO
      THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
      FITNESS, IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL,
      INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING
      FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
      NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
      WITH THE USE OR PERFORMANCE OF THIS SOFTWARE !
  
  """
  
  __version__ = '1.0.7'
  
  import collections
  import sys, os, re, subprocess
  
  import warnings
  
  ### Globals & Constants
  
  # Determine the platform's /dev/null device
  try:
      DEV_NULL = os.devnull
  except AttributeError:
      # os.devnull was added in Python 2.4, so emulate it for earlier
      # Python versions
      if sys.platform in ('dos', 'win32', 'win16'):
          # Use the old CP/M NUL as device name
          DEV_NULL = 'NUL'
      else:
          # Standard Unix uses /dev/null
          DEV_NULL = '/dev/null'
  
  # Directory to search for configuration information on Unix.
  # Constant used by test_platform to test linux_distribution().
  _UNIXCONFDIR = '/etc'
  
  ### Platform specific APIs
  
  _libc_search = re.compile(b'(__libc_init)'
                            b'|'
                            b'(GLIBC_([0-9.]+))'
                            b'|'
                            br'(libc(_\w+)?\.so(?:\.(\d[0-9.]*))?)', re.ASCII)
  
  def libc_ver(executable=sys.executable, lib='', version='',
  
               chunksize=16384):
  
      """ Tries to determine the libc version that the file executable
          (which defaults to the Python interpreter) is linked against.
  
          Returns a tuple of strings (lib,version) which default to the
          given parameters in case the lookup fails.
  
          Note that the function has intimate knowledge of how different
          libc versions add symbols to the executable and thus is probably
          only useable for executables compiled using gcc.
  
          The file is read and scanned in chunks of chunksize bytes.
  
      """
      if hasattr(os.path, 'realpath'):
          # Python 2.2 introduced os.path.realpath(); it is used
          # here to work around problems with Cygwin not being
          # able to open symlinks for reading
          executable = os.path.realpath(executable)
      with open(executable, 'rb') as f:
          binary = f.read(chunksize)
          pos = 0
          while 1:
              if b'libc' in binary or b'GLIBC' in binary:
                  m = _libc_search.search(binary, pos)
              else:
                  m = None
              if not m:
                  binary = f.read(chunksize)
                  if not binary:
                      break
                  pos = 0
                  continue
              libcinit, glibc, glibcversion, so, threads, soversion = [
                  s.decode('latin1') if s is not None else s
                  for s in m.groups()]
              if libcinit and not lib:
                  lib = 'libc'
              elif glibc:
                  if lib != 'glibc':
                      lib = 'glibc'
                      version = glibcversion
                  elif glibcversion > version:
                      version = glibcversion
              elif so:
                  if lib != 'glibc':
                      lib = 'libc'
                      if soversion and soversion > version:
                          version = soversion
                      if threads and version[-len(threads):] != threads:
                          version = version + threads
              pos = m.end()
      return lib, version
  
  def _dist_try_harder(distname, version, id):
  
      """ Tries some special tricks to get the distribution
          information in case the default method fails.
  
          Currently supports older SuSE Linux, Caldera OpenLinux and
          Slackware Linux distributions.
  
      """
      if os.path.exists('/var/adm/inst-log/info'):
          # SuSE Linux stores distribution information in that file
          distname = 'SuSE'
          for line in open('/var/adm/inst-log/info'):
              tv = line.split()
              if len(tv) == 2:
                  tag, value = tv
              else:
                  continue
              if tag == 'MIN_DIST_VERSION':
                  version = value.strip()
              elif tag == 'DIST_IDENT':
                  values = value.split('-')
                  id = values[2]
          return distname, version, id
  
      if os.path.exists('/etc/.installed'):
          # Caldera OpenLinux has some infos in that file (thanks to Colin Kong)
          for line in open('/etc/.installed'):
              pkg = line.split('-')
              if len(pkg) >= 2 and pkg[0] == 'OpenLinux':
                  # XXX does Caldera support non Intel platforms ? If yes,
                  #     where can we find the needed id ?
                  return 'OpenLinux', pkg[1], id
  
      if os.path.isdir('/usr/lib/setup'):
          # Check for slackware version tag file (thanks to Greg Andruk)
          verfiles = os.listdir('/usr/lib/setup')
          for n in range(len(verfiles)-1, -1, -1):
              if verfiles[n][:14] != 'slack-version-':
                  del verfiles[n]
          if verfiles:
              verfiles.sort()
              distname = 'slackware'
              version = verfiles[-1][14:]
              return distname, version, id
  
      return distname, version, id
  
  _release_filename = re.compile(r'(\w+)[-_](release|version)', re.ASCII)
  _lsb_release_version = re.compile(r'(.+)'
                                     ' release '
                                     '([\d.]+)'
                                     '[^(]*(?:\((.+)\))?', re.ASCII)
  _release_version = re.compile(r'([^0-9]+)'
                                 '(?: release )?'
                                 '([\d.]+)'
                                 '[^(]*(?:\((.+)\))?', re.ASCII)
  
  # See also http://www.novell.com/coolsolutions/feature/11251.html
  # and http://linuxmafia.com/faq/Admin/release-files.html
  # and http://data.linux-ntfs.org/rpm/whichrpm
  # and http://www.die.net/doc/linux/man/man1/lsb_release.1.html
  
  _supported_dists = (
      'SuSE', 'debian', 'fedora', 'redhat', 'centos',
      'mandrake', 'mandriva', 'rocks', 'slackware', 'yellowdog', 'gentoo',
      'UnitedLinux', 'turbolinux', 'arch', 'mageia', 'Ubuntu')
  
  def _parse_release_file(firstline):
  
      # Default to empty 'version' and 'id' strings.  Both defaults are used
      # when 'firstline' is empty.  'id' defaults to empty when an id can not
      # be deduced.
      version = ''
      id = ''
  
      # Parse the first line
      m = _lsb_release_version.match(firstline)
      if m is not None:
          # LSB format: "distro release x.x (codename)"
          return tuple(m.groups())
  
      # Pre-LSB format: "distro x.x (codename)"
      m = _release_version.match(firstline)
      if m is not None:
          return tuple(m.groups())
  
      # Unknown format... take the first two words
      l = firstline.strip().split()
      if l:
          version = l[0]
          if len(l) > 1:
              id = l[1]
      return '', version, id
  
  _distributor_id_file_re = re.compile("(?:DISTRIB_ID\s*=)\s*(.*)", re.I)
  _release_file_re = re.compile("(?:DISTRIB_RELEASE\s*=)\s*(.*)", re.I)
  _codename_file_re = re.compile("(?:DISTRIB_CODENAME\s*=)\s*(.*)", re.I)
  
  def linux_distribution(distname='', version='', id='',
  
                         supported_dists=_supported_dists,
                         full_distribution_name=1):
      import warnings
      warnings.warn("dist() and linux_distribution() functions are deprecated "
                    "in Python 3.5 and will be removed in Python 3.7",
                    PendingDeprecationWarning, stacklevel=2)
      return _linux_distribution(distname, version, id, supported_dists,
                                 full_distribution_name)
  
  def _linux_distribution(distname, version, id, supported_dists,
                          full_distribution_name):
  
      """ Tries to determine the name of the Linux OS distribution name.
  
          The function first looks for a distribution release file in
          /etc and then reverts to _dist_try_harder() in case no
          suitable files are found.
  
          supported_dists may be given to define the set of Linux
          distributions to look for. It defaults to a list of currently
          supported Linux distributions identified by their release file
          name.
  
          If full_distribution_name is true (default), the full
          distribution read from the OS is returned. Otherwise the short
          name taken from supported_dists is used.
  
          Returns a tuple (distname, version, id) which default to the
          args given as parameters.
  
      """
      # check for the Debian/Ubuntu /etc/lsb-release file first, needed so
      # that the distribution doesn't get identified as Debian.
      try:
          with open("/etc/lsb-release", "r") as etclsbrel:
              for line in etclsbrel:
                  m = _distributor_id_file_re.search(line)
                  if m:
                      _u_distname = m.group(1).strip()
                  m = _release_file_re.search(line)
                  if m:
                      _u_version = m.group(1).strip()
                  m = _codename_file_re.search(line)
                  if m:
                      _u_id = m.group(1).strip()
              if _u_distname and _u_version:
                  return (_u_distname, _u_version, _u_id)
      except (EnvironmentError, UnboundLocalError):
              pass
  
      try:
          etc = os.listdir(_UNIXCONFDIR)
      except OSError:
          # Probably not a Unix system
          return distname, version, id
      etc.sort()
      for file in etc:
          m = _release_filename.match(file)
          if m is not None:
              _distname, dummy = m.groups()
              if _distname in supported_dists:
                  distname = _distname
                  break
      else:
          return _dist_try_harder(distname, version, id)
  
      # Read the first line
      with open(os.path.join(_UNIXCONFDIR, file), 'r',
                encoding='utf-8', errors='surrogateescape') as f:
          firstline = f.readline()
      _distname, _version, _id = _parse_release_file(firstline)
  
      if _distname and full_distribution_name:
          distname = _distname
      if _version:
          version = _version
      if _id:
          id = _id
      return distname, version, id
  
  # To maintain backwards compatibility:
  
  def dist(distname='', version='', id='',
  
           supported_dists=_supported_dists):
  
      """ Tries to determine the name of the Linux OS distribution name.
  
          The function first looks for a distribution release file in
          /etc and then reverts to _dist_try_harder() in case no
          suitable files are found.
  
          Returns a tuple (distname, version, id) which default to the
          args given as parameters.
  
      """
      import warnings
      warnings.warn("dist() and linux_distribution() functions are deprecated "
                    "in Python 3.5 and will be removed in Python 3.7",
                    PendingDeprecationWarning, stacklevel=2)
      return _linux_distribution(distname, version, id,
                                 supported_dists=supported_dists,
                                 full_distribution_name=0)
  
  def popen(cmd, mode='r', bufsize=-1):
  
      """ Portable popen() interface.
      """
      import warnings
      warnings.warn('use os.popen instead', DeprecationWarning, stacklevel=2)
      return os.popen(cmd, mode, bufsize)
  
  def _norm_version(version, build=''):
  
      """ Normalize the version and build strings and return a single
          version string using the format major.minor.build (or patchlevel).
      """
      l = version.split('.')
      if build:
          l.append(build)
      try:
          ints = map(int, l)
      except ValueError:
          strings = l
      else:
          strings = list(map(str, ints))
      version = '.'.join(strings[:3])
      return version
  
  _ver_output = re.compile(r'(?:([\w ]+) ([\w.]+) '
                           '.*'
                           '\[.* ([\d.]+)\])')
  
  # Examples of VER command output:
  #
  #   Windows 2000:  Microsoft Windows 2000 [Version 5.00.2195]
  #   Windows XP:    Microsoft Windows XP [Version 5.1.2600]
  #   Windows Vista: Microsoft Windows [Version 6.0.6002]
  #
  # Note that the "Version" string gets localized on different
  # Windows versions.
  
  def _syscmd_ver(system='', release='', version='',
  
                 supported_platforms=('win32', 'win16', 'dos')):
  
      """ Tries to figure out the OS version used and returns
          a tuple (system, release, version).
  
          It uses the "ver" shell command for this which is known
          to exists on Windows, DOS. XXX Others too ?
  
          In case this fails, the given parameters are used as
          defaults.
  
      """
      if sys.platform not in supported_platforms:
          return system, release, version
  
      # Try some common cmd strings
      for cmd in ('ver', 'command /c ver', 'cmd /c ver'):
          try:
              pipe = os.popen(cmd)
              info = pipe.read()
              if pipe.close():
                  raise OSError('command failed')
              # XXX How can I suppress shell errors from being written
              #     to stderr ?
          except OSError as why:
              #print 'Command %s failed: %s' % (cmd, why)
              continue
          else:
              break
      else:
          return system, release, version
  
      # Parse the output
      info = info.strip()
      m = _ver_output.match(info)
      if m is not None:
          system, release, version = m.groups()
          # Strip trailing dots from version and release
          if release[-1] == '.':
              release = release[:-1]
          if version[-1] == '.':
              version = version[:-1]
          # Normalize the version and build strings (eliminating additional
          # zeros)
          version = _norm_version(version)
      return system, release, version
  
  _WIN32_CLIENT_RELEASES = {
      (5, 0): "2000",
      (5, 1): "XP",
      # Strictly, 5.2 client is XP 64-bit, but platform.py historically
      # has always called it 2003 Server
      (5, 2): "2003Server",
      (5, None): "post2003",
  
      (6, 0): "Vista",
      (6, 1): "7",
      (6, 2): "8",
      (6, 3): "8.1",
      (6, None): "post8.1",
  
      (10, 0): "10",
      (10, None): "post10",
  }
  
  # Server release name lookup will default to client names if necessary
  _WIN32_SERVER_RELEASES = {
      (5, 2): "2003Server",
  
      (6, 0): "2008Server",
      (6, 1): "2008ServerR2",
      (6, 2): "2012Server",
      (6, 3): "2012ServerR2",
      (6, None): "post2012ServerR2",
  }
  
  def _get_real_winver(maj, min, build):
      if maj < 6 or (maj == 6 and min < 2):
          return maj, min, build
  
      from ctypes import (c_buffer, POINTER, byref, create_unicode_buffer,
                          Structure, WinDLL)
      from ctypes.wintypes import DWORD, HANDLE
  
      class VS_FIXEDFILEINFO(Structure):
          _fields_ = [
              ("dwSignature", DWORD),
              ("dwStrucVersion", DWORD),
              ("dwFileVersionMS", DWORD),
              ("dwFileVersionLS", DWORD),
              ("dwProductVersionMS", DWORD),
              ("dwProductVersionLS", DWORD),
              ("dwFileFlagsMask", DWORD),
              ("dwFileFlags", DWORD),
              ("dwFileOS", DWORD),
              ("dwFileType", DWORD),
              ("dwFileSubtype", DWORD),
              ("dwFileDateMS", DWORD),
              ("dwFileDateLS", DWORD),
          ]
  
      kernel32 = WinDLL('kernel32')
      version = WinDLL('version')
  
      # We will immediately double the length up to MAX_PATH, but the
      # path may be longer, so we retry until the returned string is
      # shorter than our buffer.
      name_len = actual_len = 130
      while actual_len == name_len:
          name_len *= 2
          name = create_unicode_buffer(name_len)
          actual_len = kernel32.GetModuleFileNameW(HANDLE(kernel32._handle),
                                                   name, len(name))
          if not actual_len:
              return maj, min, build
  
      size = version.GetFileVersionInfoSizeW(name, None)
      if not size:
          return maj, min, build
  
      ver_block = c_buffer(size)
      if (not version.GetFileVersionInfoW(name, None, size, ver_block) or
          not ver_block):
          return maj, min, build
  
      pvi = POINTER(VS_FIXEDFILEINFO)()
      if not version.VerQueryValueW(ver_block, "", byref(pvi), byref(DWORD())):
          return maj, min, build
  
      maj = pvi.contents.dwProductVersionMS >> 16
      min = pvi.contents.dwProductVersionMS & 0xFFFF
      build = pvi.contents.dwProductVersionLS >> 16
  
      return maj, min, build
  
  def win32_ver(release='', version='', csd='', ptype=''):
      try:
          from sys import getwindowsversion
      except ImportError:
          return release, version, csd, ptype
      try:
          from winreg import OpenKeyEx, QueryValueEx, CloseKey, HKEY_LOCAL_MACHINE
      except ImportError:
          from _winreg import OpenKeyEx, QueryValueEx, CloseKey, HKEY_LOCAL_MACHINE
  
      winver = getwindowsversion()
      maj, min, build = _get_real_winver(*winver[:3])
      version = '{0}.{1}.{2}'.format(maj, min, build)
  
      release = (_WIN32_CLIENT_RELEASES.get((maj, min)) or
                 _WIN32_CLIENT_RELEASES.get((maj, None)) or
                 release)
  
      # getwindowsversion() reflect the compatibility mode Python is
      # running under, and so the service pack value is only going to be
      # valid if the versions match.
      if winver[:2] == (maj, min):
          try:
              csd = 'SP{}'.format(winver.service_pack_major)
          except AttributeError:
              if csd[:13] == 'Service Pack ':
                  csd = 'SP' + csd[13:]
  
      # VER_NT_SERVER = 3
      if getattr(winver, 'product_type', None) == 3:
          release = (_WIN32_SERVER_RELEASES.get((maj, min)) or
                     _WIN32_SERVER_RELEASES.get((maj, None)) or
                     release)
  
      key = None
      try:
          key = OpenKeyEx(HKEY_LOCAL_MACHINE,
                          r'SOFTWARE\Microsoft\Windows NT\CurrentVersion')
          ptype = QueryValueEx(key, 'CurrentType')[0]
      except:
          pass
      finally:
          if key:
              CloseKey(key)
  
      return release, version, csd, ptype
  
  
  def _mac_ver_xml():
      fn = '/System/Library/CoreServices/SystemVersion.plist'
      if not os.path.exists(fn):
          return None
  
      try:
          import plistlib
      except ImportError:
          return None
  
      with open(fn, 'rb') as f:
          pl = plistlib.load(f)
      release = pl['ProductVersion']
      versioninfo = ('', '', '')
      machine = os.uname().machine
      if machine in ('ppc', 'Power Macintosh'):
          # Canonical name
          machine = 'PowerPC'
  
      return release, versioninfo, machine
  
  
  def mac_ver(release='', versioninfo=('', '', ''), machine=''):
  
      """ Get MacOS version information and return it as tuple (release,
          versioninfo, machine) with versioninfo being a tuple (version,
          dev_stage, non_release_version).
  
          Entries which cannot be determined are set to the parameter values
          which default to ''. All tuple entries are strings.
      """
  
      # First try reading the information from an XML file which should
      # always be present
      info = _mac_ver_xml()
      if info is not None:
          return info
  
      # If that also doesn't work return the default values
      return release, versioninfo, machine
  
  def _java_getprop(name, default):
  
      from java.lang import System
      try:
          value = System.getProperty(name)
          if value is None:
              return default
          return value
      except AttributeError:
          return default
  
  def java_ver(release='', vendor='', vminfo=('', '', ''), osinfo=('', '', '')):
  
      """ Version interface for Jython.
  
          Returns a tuple (release, vendor, vminfo, osinfo) with vminfo being
          a tuple (vm_name, vm_release, vm_vendor) and osinfo being a
          tuple (os_name, os_version, os_arch).
  
          Values which cannot be determined are set to the defaults
          given as parameters (which all default to '').
  
      """
      # Import the needed APIs
      try:
          import java.lang
      except ImportError:
          return release, vendor, vminfo, osinfo
  
      vendor = _java_getprop('java.vendor', vendor)
      release = _java_getprop('java.version', release)
      vm_name, vm_release, vm_vendor = vminfo
      vm_name = _java_getprop('java.vm.name', vm_name)
      vm_vendor = _java_getprop('java.vm.vendor', vm_vendor)
      vm_release = _java_getprop('java.vm.version', vm_release)
      vminfo = vm_name, vm_release, vm_vendor
      os_name, os_version, os_arch = osinfo
      os_arch = _java_getprop('java.os.arch', os_arch)
      os_name = _java_getprop('java.os.name', os_name)
      os_version = _java_getprop('java.os.version', os_version)
      osinfo = os_name, os_version, os_arch
  
      return release, vendor, vminfo, osinfo
  
  ### System name aliasing
  
  def system_alias(system, release, version):
  
      """ Returns (system, release, version) aliased to common
          marketing names used for some systems.
  
          It also does some reordering of the information in some cases
          where it would otherwise cause confusion.
  
      """
      if system == 'Rhapsody':
          # Apple's BSD derivative
          # XXX How can we determine the marketing release number ?
          return 'MacOS X Server', system+release, version
  
      elif system == 'SunOS':
          # Sun's OS
          if release < '5':
              # These releases use the old name SunOS
              return system, release, version
          # Modify release (marketing release = SunOS release - 3)
          l = release.split('.')
          if l:
              try:
                  major = int(l[0])
              except ValueError:
                  pass
              else:
                  major = major - 3
                  l[0] = str(major)
                  release = '.'.join(l)
          if release < '6':
              system = 'Solaris'
          else:
              # XXX Whatever the new SunOS marketing name is...
              system = 'Solaris'
  
      elif system == 'IRIX64':
          # IRIX reports IRIX64 on platforms with 64-bit support; yet it
          # is really a version and not a different platform, since 32-bit
          # apps are also supported..
          system = 'IRIX'
          if version:
              version = version + ' (64bit)'
          else:
              version = '64bit'
  
      elif system in ('win32', 'win16'):
          # In case one of the other tricks
          system = 'Windows'
  
      return system, release, version
  
  ### Various internal helpers
  
  def _platform(*args):
  
      """ Helper to format the platform string in a filename
          compatible format e.g. "system-version-machine".
      """
      # Format the platform string
      platform = '-'.join(x.strip() for x in filter(len, args))
  
      # Cleanup some possible filename obstacles...
      platform = platform.replace(' ', '_')
      platform = platform.replace('/', '-')
      platform = platform.replace('\\', '-')
      platform = platform.replace(':', '-')
      platform = platform.replace(';', '-')
      platform = platform.replace('"', '-')
      platform = platform.replace('(', '-')
      platform = platform.replace(')', '-')
  
      # No need to report 'unknown' information...
      platform = platform.replace('unknown', '')
  
      # Fold '--'s and remove trailing '-'
      while 1:
          cleaned = platform.replace('--', '-')
          if cleaned == platform:
              break
          platform = cleaned
      while platform[-1] == '-':
          platform = platform[:-1]
  
      return platform
  
  def _node(default=''):
  
      """ Helper to determine the node name of this machine.
      """
      try:
          import socket
      except ImportError:
          # No sockets...
          return default
      try:
          return socket.gethostname()
      except OSError:
          # Still not working...
          return default
  
  def _follow_symlinks(filepath):
  
      """ In case filepath is a symlink, follow it until a
          real file is reached.
      """
      filepath = os.path.abspath(filepath)
      while os.path.islink(filepath):
          filepath = os.path.normpath(
              os.path.join(os.path.dirname(filepath), os.readlink(filepath)))
      return filepath
  
  def _syscmd_uname(option, default=''):
  
      """ Interface to the system's uname command.
      """
      if sys.platform in ('dos', 'win32', 'win16'):
          # XXX Others too ?
          return default
      try:
          f = os.popen('uname %s 2> %s' % (option, DEV_NULL))
      except (AttributeError, OSError):
          return default
      output = f.read().strip()
      rc = f.close()
      if not output or rc:
          return default
      else:
          return output
  
  def _syscmd_file(target, default=''):
  
      """ Interface to the system's file command.
  
          The function uses the -b option of the file command to have it
          omit the filename in its output. Follow the symlinks. It returns
          default in case the command should fail.
  
      """
      if sys.platform in ('dos', 'win32', 'win16'):
          # XXX Others too ?
          return default
      target = _follow_symlinks(target)
      try:
          proc = subprocess.Popen(['file', target],
                  stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
  
      except (AttributeError, OSError):
          return default
      output = proc.communicate()[0].decode('latin-1')
      rc = proc.wait()
      if not output or rc:
          return default
      else:
          return output
  
  ### Information about the used architecture
  
  # Default values for architecture; non-empty strings override the
  # defaults given as parameters
  _default_architecture = {
      'win32': ('', 'WindowsPE'),
      'win16': ('', 'Windows'),
      'dos': ('', 'MSDOS'),
  }
  
  def architecture(executable=sys.executable, bits='', linkage=''):
  
      """ Queries the given executable (defaults to the Python interpreter
          binary) for various architecture information.
  
          Returns a tuple (bits, linkage) which contains information about
          the bit architecture and the linkage format used for the
          executable. Both values are returned as strings.
  
          Values that cannot be determined are returned as given by the
          parameter presets. If bits is given as '', the sizeof(pointer)
          (or sizeof(long) on Python version < 1.5.2) is used as
          indicator for the supported pointer size.
  
          The function relies on the system's "file" command to do the
          actual work. This is available on most if not all Unix
          platforms. On some non-Unix platforms where the "file" command
          does not exist and the executable is set to the Python interpreter
          binary defaults from _default_architecture are used.
  
      """
      # Use the sizeof(pointer) as default number of bits if nothing
      # else is given as default.
      if not bits:
          import struct
          try:
              size = struct.calcsize('P')
          except struct.error:
              # Older installations can only query longs
              size = struct.calcsize('l')
          bits = str(size*8) + 'bit'
  
      # Get data from the 'file' system command
      if executable:
          fileout = _syscmd_file(executable, '')
      else:
          fileout = ''
  
      if not fileout and \
         executable == sys.executable:
          # "file" command did not return anything; we'll try to provide
          # some sensible defaults then...
          if sys.platform in _default_architecture:
              b, l = _default_architecture[sys.platform]
              if b:
                  bits = b
              if l:
                  linkage = l
          return bits, linkage
  
      if 'executable' not in fileout:
          # Format not supported
          return bits, linkage
  
      # Bits
      if '32-bit' in fileout:
          bits = '32bit'
      elif 'N32' in fileout:
          # On Irix only
          bits = 'n32bit'
      elif '64-bit' in fileout:
          bits = '64bit'
  
      # Linkage
      if 'ELF' in fileout:
          linkage = 'ELF'
      elif 'PE' in fileout:
          # E.g. Windows uses this format
          if 'Windows' in fileout:
              linkage = 'WindowsPE'
          else:
              linkage = 'PE'
      elif 'COFF' in fileout:
          linkage = 'COFF'
      elif 'MS-DOS' in fileout:
          linkage = 'MSDOS'
      else:
          # XXX the A.OUT format also falls under this class...
          pass
  
      return bits, linkage
  
  ### Portable uname() interface
  
  uname_result = collections.namedtuple("uname_result",
                      "system node release version machine processor")
  
  _uname_cache = None
  
  def uname():
  
      """ Fairly portable uname interface. Returns a tuple
          of strings (system, node, release, version, machine, processor)
          identifying the underlying platform.
  
          Note that unlike the os.uname function this also returns
          possible processor information as an additional tuple entry.
  
          Entries which cannot be determined are set to ''.
  
      """
      global _uname_cache
      no_os_uname = 0
  
      if _uname_cache is not None:
          return _uname_cache
  
      processor = ''
  
      # Get some infos from the builtin os.uname API...
      try:
          system, node, release, version, machine = os.uname()
      except AttributeError:
          no_os_uname = 1
  
      if no_os_uname or not list(filter(None, (system, node, release, version, machine))):
          # Hmm, no there is either no uname or uname has returned
          #'unknowns'... we'll have to poke around the system then.
          if no_os_uname:
              system = sys.platform
              release = ''
              version = ''
              node = _node()
              machine = ''
  
          use_syscmd_ver = 1
  
          # Try win32_ver() on win32 platforms
          if system == 'win32':
              release, version, csd, ptype = win32_ver()
              if release and version:
                  use_syscmd_ver = 0
              # Try to use the PROCESSOR_* environment variables
              # available on Win XP and later; see
              # http://support.microsoft.com/kb/888731 and
              # http://www.geocities.com/rick_lively/MANUALS/ENV/MSWIN/PROCESSI.HTM
              if not machine:
                  # WOW64 processes mask the native architecture
                  if "PROCESSOR_ARCHITEW6432" in os.environ:
                      machine = os.environ.get("PROCESSOR_ARCHITEW6432", '')
                  else:
                      machine = os.environ.get('PROCESSOR_ARCHITECTURE', '')
              if not processor:
                  processor = os.environ.get('PROCESSOR_IDENTIFIER', machine)
  
          # Try the 'ver' system command available on some
          # platforms
          if use_syscmd_ver:
              system, release, version = _syscmd_ver(system)
              # Normalize system to what win32_ver() normally returns
              # (_syscmd_ver() tends to return the vendor name as well)
              if system == 'Microsoft Windows':
                  system = 'Windows'
              elif system == 'Microsoft' and release == 'Windows':
                  # Under Windows Vista and Windows Server 2008,
                  # Microsoft changed the output of the ver command. The
                  # release is no longer printed.  This causes the
                  # system and release to be misidentified.
                  system = 'Windows'
                  if '6.0' == version[:3]:
                      release = 'Vista'
                  else:
                      release = ''
  
          # In case we still don't know anything useful, we'll try to
          # help ourselves
          if system in ('win32', 'win16'):
              if not version:
                  if system == 'win32':
                      version = '32bit'
                  else:
                      version = '16bit'
              system = 'Windows'
  
          elif system[:4] == 'java':
              release, vendor, vminfo, osinfo = java_ver()
              system = 'Java'
              version = ', '.join(vminfo)
              if not version:
                  version = vendor
  
      # System specific extensions
      if system == 'OpenVMS':
          # OpenVMS seems to have release and version mixed up
          if not release or release == '0':
              release = version
              version = ''
          # Get processor information
          try:
              import vms_lib
          except ImportError:
              pass
          else:
              csid, cpu_number = vms_lib.getsyi('SYI$_CPU', 0)
              if (cpu_number >= 128):
                  processor = 'Alpha'
              else:
                  processor = 'VAX'
      if not processor:
          # Get processor information from the uname system command
          processor = _syscmd_uname('-p', '')
  
      #If any unknowns still exist, replace them with ''s, which are more portable
      if system == 'unknown':
          system = ''
      if node == 'unknown':
          node = ''
      if release == 'unknown':
          release = ''
      if version == 'unknown':
          version = ''
      if machine == 'unknown':
          machine = ''
      if processor == 'unknown':
          processor = ''
  
      #  normalize name
      if system == 'Microsoft' and release == 'Windows':
          system = 'Windows'
          release = 'Vista'
  
      _uname_cache = uname_result(system, node, release, version,
                                  machine, processor)
      return _uname_cache
  
  ### Direct interfaces to some of the uname() return values
  
  def system():
  
      """ Returns the system/OS name, e.g. 'Linux', 'Windows' or 'Java'.
  
          An empty string is returned if the value cannot be determined.
  
      """
      return uname().system
  
  def node():
  
      """ Returns the computer's network name (which may not be fully
          qualified)
  
          An empty string is returned if the value cannot be determined.
  
      """
      return uname().node
  
  def release():
  
      """ Returns the system's release, e.g. '2.2.0' or 'NT'
  
          An empty string is returned if the value cannot be determined.
  
      """
      return uname().release
  
  def version():
  
      """ Returns the system's release version, e.g. '#3 on degas'
  
          An empty string is returned if the value cannot be determined.
  
      """
      return uname().version
  
  def machine():
  
      """ Returns the machine type, e.g. 'i386'
  
          An empty string is returned if the value cannot be determined.
  
      """
      return uname().machine
  
  def processor():
  
      """ Returns the (true) processor name, e.g. 'amdk6'
  
          An empty string is returned if the value cannot be
          determined. Note that many platforms do not provide this
          information or simply return the same value as for machine(),
          e.g.  NetBSD does this.
  
      """
      return uname().processor
  
  ### Various APIs for extracting information from sys.version
  
  _sys_version_parser = re.compile(
      r'([\w.+]+)\s*'
      '\(#?([^,]+),\s*([\w ]+),\s*([\w :]+)\)\s*'
      '\[([^\]]+)\]?', re.ASCII)
  
  _ironpython_sys_version_parser = re.compile(
      r'IronPython\s*'
      '([\d\.]+)'
      '(?: \(([\d\.]+)\))?'
      ' on (.NET [\d\.]+)', re.ASCII)
  
  # IronPython covering 2.6 and 2.7
  _ironpython26_sys_version_parser = re.compile(
      r'([\d.]+)\s*'
      '\(IronPython\s*'
      '[\d.]+\s*'
      '\(([\d.]+)\) on ([\w.]+ [\d.]+(?: \(\d+-bit\))?)\)'
  )
  
  _pypy_sys_version_parser = re.compile(
      r'([\w.+]+)\s*'
      '\(#?([^,]+),\s*([\w ]+),\s*([\w :]+)\)\s*'
      '\[PyPy [^\]]+\]?')
  
  _sys_version_cache = {}
  
  def _sys_version(sys_version=None):
  
      """ Returns a parsed version of Python's sys.version as tuple
          (name, version, branch, revision, buildno, builddate, compiler)
          referring to the Python implementation name, version, branch,
          revision, build number, build date/time as string and the compiler
          identification string.
  
          Note that unlike the Python sys.version, the returned value
          for the Python version will always include the patchlevel (it
          defaults to '.0').
  
          The function returns empty strings for tuple entries that
          cannot be determined.
  
          sys_version may be given to parse an alternative version
          string, e.g. if the version was read from a different Python
          interpreter.
  
      """
      # Get the Python version
      if sys_version is None:
          sys_version = sys.version
  
      # Try the cache first
      result = _sys_version_cache.get(sys_version, None)
      if result is not None:
          return result
  
      # Parse it
      if 'IronPython' in sys_version:
          # IronPython
          name = 'IronPython'
          if sys_version.startswith('IronPython'):
              match = _ironpython_sys_version_parser.match(sys_version)
          else:
              match = _ironpython26_sys_version_parser.match(sys_version)
  
          if match is None:
              raise ValueError(
                  'failed to parse IronPython sys.version: %s' %
                  repr(sys_version))
  
          version, alt_version, compiler = match.groups()
          buildno = ''
          builddate = ''
  
      elif sys.platform.startswith('java'):
          # Jython
          name = 'Jython'
          match = _sys_version_parser.match(sys_version)
          if match is None:
              raise ValueError(
                  'failed to parse Jython sys.version: %s' %
                  repr(sys_version))
          version, buildno, builddate, buildtime, _ = match.groups()
          compiler = sys.platform
  
      elif "PyPy" in sys_version:
          # PyPy
          name = "PyPy"
          match = _pypy_sys_version_parser.match(sys_version)
          if match is None:
              raise ValueError("failed to parse PyPy sys.version: %s" %
                               repr(sys_version))
          version, buildno, builddate, buildtime = match.groups()
          compiler = ""
  
      else:
          # CPython
          match = _sys_version_parser.match(sys_version)
          if match is None:
              raise ValueError(
                  'failed to parse CPython sys.version: %s' %
                  repr(sys_version))
          version, buildno, builddate, buildtime, compiler = \
                match.groups()
          name = 'CPython'
          builddate = builddate + ' ' + buildtime
  
      if hasattr(sys, '_mercurial'):
          _, branch, revision = sys._mercurial
      elif hasattr(sys, 'subversion'):
          # sys.subversion was added in Python 2.5
          _, branch, revision = sys.subversion
      else:
          branch = ''
          revision = ''
  
      # Add the patchlevel version if missing
      l = version.split('.')
      if len(l) == 2:
          l.append('0')
          version = '.'.join(l)
  
      # Build and cache the result
      result = (name, version, branch, revision, buildno, builddate, compiler)
      _sys_version_cache[sys_version] = result
      return result
  
  def python_implementation():
  
      """ Returns a string identifying the Python implementation.
  
          Currently, the following implementations are identified:
            'CPython' (C implementation of Python),
            'IronPython' (.NET implementation of Python),
            'Jython' (Java implementation of Python),
            'PyPy' (Python implementation of Python).
  
      """
      return _sys_version()[0]
  
  def python_version():
  
      """ Returns the Python version as string 'major.minor.patchlevel'
  
          Note that unlike the Python sys.version, the returned value
          will always include the patchlevel (it defaults to 0).
  
      """
      return _sys_version()[1]
  
  def python_version_tuple():
  
      """ Returns the Python version as tuple (major, minor, patchlevel)
          of strings.
  
          Note that unlike the Python sys.version, the returned value
          will always include the patchlevel (it defaults to 0).
  
      """
      return tuple(_sys_version()[1].split('.'))
  
  def python_branch():
  
      """ Returns a string identifying the Python implementation
          branch.
  
          For CPython this is the Subversion branch from which the
          Python binary was built.
  
          If not available, an empty string is returned.
  
      """
  
      return _sys_version()[2]
  
  def python_revision():
  
      """ Returns a string identifying the Python implementation
          revision.
  
          For CPython this is the Subversion revision from which the
          Python binary was built.
  
          If not available, an empty string is returned.
  
      """
      return _sys_version()[3]
  
  def python_build():
  
      """ Returns a tuple (buildno, builddate) stating the Python
          build number and date as strings.
  
      """
      return _sys_version()[4:6]
  
  def python_compiler():
  
      """ Returns a string identifying the compiler used for compiling
          Python.
  
      """
      return _sys_version()[6]
  
  ### The Opus Magnum of platform strings :-)
  
  _platform_cache = {}
  
  def platform(aliased=0, terse=0):
  
      """ Returns a single string identifying the underlying platform
          with as much useful information as possible (but no more :).
  
          The output is intended to be human readable rather than
          machine parseable. It may look different on different
          platforms and this is intended.
  
          If "aliased" is true, the function will use aliases for
          various platforms that report system names which differ from
          their common names, e.g. SunOS will be reported as
          Solaris. The system_alias() function is used to implement
          this.
  
          Setting terse to true causes the function to return only the
          absolute minimum information needed to identify the platform.
  
      """
      result = _platform_cache.get((aliased, terse), None)
      if result is not None:
          return result
  
      # Get uname information and then apply platform specific cosmetics
      # to it...
      system, node, release, version, machine, processor = uname()
      if machine == processor:
          processor = ''
      if aliased:
          system, release, version = system_alias(system, release, version)
  
      if system == 'Windows':
          # MS platforms
          rel, vers, csd, ptype = win32_ver(version)
          if terse:
              platform = _platform(system, release)
          else:
              platform = _platform(system, release, version, csd)
  
      elif system in ('Linux',):
          # Linux based systems
          with warnings.catch_warnings():
              # see issue #1322 for more information
              warnings.filterwarnings(
                  'ignore',
                  'dist\(\) and linux_distribution\(\) '
                  'functions are deprecated .*',
                  PendingDeprecationWarning,
              )
              distname, distversion, distid = dist('')
          if distname and not terse:
              platform = _platform(system, release, machine, processor,
                                   'with',
                                   distname, distversion, distid)
          else:
              # If the distribution name is unknown check for libc vs. glibc
              libcname, libcversion = libc_ver(sys.executable)
              platform = _platform(system, release, machine, processor,
                                   'with',
                                   libcname+libcversion)
      elif system == 'Java':
          # Java platforms
          r, v, vminfo, (os_name, os_version, os_arch) = java_ver()
          if terse or not os_name:
              platform = _platform(system, release, version)
          else:
              platform = _platform(system, release, version,
                                   'on',
                                   os_name, os_version, os_arch)
  
      elif system == 'MacOS':
          # MacOS platforms
          if terse:
              platform = _platform(system, release)
          else:
              platform = _platform(system, release, machine)
  
      else:
          # Generic handler
          if terse:
              platform = _platform(system, release)
          else:
              bits, linkage = architecture(sys.executable)
              platform = _platform(system, release, machine,
                                   processor, bits, linkage)
  
      _platform_cache[(aliased, terse)] = platform
      return platform
  
  ### Command line interface
  
  if __name__ == '__main__':
      # Default is to print the aliased verbose platform string
      terse = ('terse' in sys.argv or '--terse' in sys.argv)
      aliased = (not 'nonaliased' in sys.argv and not '--nonaliased' in sys.argv)
      print(platform(aliased, terse))
      sys.exit(0)
  