text: # Copyright (c) 2009, Giampaolo Rodola'. All rights reserved.
  # Use of this source code is governed by a BSD-style license that can be
  # found in the LICENSE file.
  
  """Linux platform implementation."""
  
  from __future__ import division
  
  import base64
  import collections
  import errno
  import functools
  import glob
  import os
  import re
  import socket
  import struct
  import sys
  import traceback
  import warnings
  from collections import defaultdict
  from collections import namedtuple
  
  from . import _common
  from . import _psposix
  from . import _psutil_linux as cext
  from . import _psutil_posix as cext_posix
  from ._common import decode
  from ._common import get_procfs_path
  from ._common import isfile_strict
  from ._common import memoize
  from ._common import memoize_when_activated
  from ._common import NIC_DUPLEX_FULL
  from ._common import NIC_DUPLEX_HALF
  from ._common import NIC_DUPLEX_UNKNOWN
  from ._common import open_binary
  from ._common import open_text
  from ._common import parse_environ_block
  from ._common import path_exists_strict
  from ._common import supports_ipv6
  from ._common import usage_percent
  from ._compat import b
  from ._compat import basestring
  from ._compat import FileNotFoundError
  from ._compat import PermissionError
  from ._compat import ProcessLookupError
  from ._compat import PY3
  
  if sys.version_info >= (3, 4):
      import enum
  else:
      enum = None
  
  
  __extra__all__ = [
      #
      'PROCFS_PATH',
      # io prio constants
      "IOPRIO_CLASS_NONE", "IOPRIO_CLASS_RT", "IOPRIO_CLASS_BE",
      "IOPRIO_CLASS_IDLE",
      # connection status constants
      "CONN_ESTABLISHED", "CONN_SYN_SENT", "CONN_SYN_RECV", "CONN_FIN_WAIT1",
      "CONN_FIN_WAIT2", "CONN_TIME_WAIT", "CONN_CLOSE", "CONN_CLOSE_WAIT",
      "CONN_LAST_ACK", "CONN_LISTEN", "CONN_CLOSING", ]
  
  
  # =====================================================================
  # --- globals
  # =====================================================================
  
  
  POWER_SUPPLY_PATH = "/sys/class/power_supply"
  HAS_SMAPS = os.path.exists('/proc/%s/smaps' % os.getpid())
  HAS_PRLIMIT = hasattr(cext, "linux_prlimit")
  HAS_PROC_IO_PRIORITY = hasattr(cext, "proc_ioprio_get")
  HAS_CPU_AFFINITY = hasattr(cext, "proc_cpu_affinity_get")
  _DEFAULT = object()
  
  # RLIMIT_* constants, not guaranteed to be present on all kernels
  if HAS_PRLIMIT:
      for name in dir(cext):
          if name.startswith('RLIM'):
              __extra__all__.append(name)
  
  # Number of clock ticks per second
  CLOCK_TICKS = os.sysconf("SC_CLK_TCK")
  PAGESIZE = os.sysconf("SC_PAGE_SIZE")
  BOOT_TIME = None  # set later
  # Used when reading "big" files, namely /proc/{pid}/smaps and /proc/net/*.
  # On Python 2, using a buffer with open() for such files may result in a
  # speedup, see: https://github.com/giampaolo/psutil/issues/708
  BIGFILE_BUFFERING = -1 if PY3 else 8192
  LITTLE_ENDIAN = sys.byteorder == 'little'
  
  # "man iostat" states that sectors are equivalent with blocks and have
  # a size of 512 bytes. Despite this value can be queried at runtime
  # via /sys/block/{DISK}/queue/hw_sector_size and results may vary
  # between 1k, 2k, or 4k... 512 appears to be a magic constant used
  # throughout Linux source code:
  # * https://stackoverflow.com/a/38136179/376587
  # * https://lists.gt.net/linux/kernel/2241060
  # * https://github.com/giampaolo/psutil/issues/1305
  # * https://github.com/torvalds/linux/blob/
  #     4f671fe2f9523a1ea206f63fe60a7c7b3a56d5c7/include/linux/bio.h#L99
  # * https://lkml.org/lkml/2015/8/17/234
  DISK_SECTOR_SIZE = 512
  
  if enum is None:
      AF_LINK = socket.AF_PACKET
  else:
      AddressFamily = enum.IntEnum('AddressFamily',
                                   {'AF_LINK': int(socket.AF_PACKET)})
      AF_LINK = AddressFamily.AF_LINK
  
  # ioprio_* constants http://linux.die.net/man/2/ioprio_get
  if enum is None:
      IOPRIO_CLASS_NONE = 0
      IOPRIO_CLASS_RT = 1
      IOPRIO_CLASS_BE = 2
      IOPRIO_CLASS_IDLE = 3
  else:
      class IOPriority(enum.IntEnum):
          IOPRIO_CLASS_NONE = 0
          IOPRIO_CLASS_RT = 1
          IOPRIO_CLASS_BE = 2
          IOPRIO_CLASS_IDLE = 3
  
      globals().update(IOPriority.__members__)
  
  # See:
  # https://github.com/torvalds/linux/blame/master/fs/proc/array.c
  # ...and (TASK_* constants):
  # https://github.com/torvalds/linux/blob/master/include/linux/sched.h
  PROC_STATUSES = {
      "R": _common.STATUS_RUNNING,
      "S": _common.STATUS_SLEEPING,
      "D": _common.STATUS_DISK_SLEEP,
      "T": _common.STATUS_STOPPED,
      "t": _common.STATUS_TRACING_STOP,
      "Z": _common.STATUS_ZOMBIE,
      "X": _common.STATUS_DEAD,
      "x": _common.STATUS_DEAD,
      "K": _common.STATUS_WAKE_KILL,
      "W": _common.STATUS_WAKING,
      "I": _common.STATUS_IDLE,
      "P": _common.STATUS_PARKED,
  }
  
  # https://github.com/torvalds/linux/blob/master/include/net/tcp_states.h
  TCP_STATUSES = {
      "01": _common.CONN_ESTABLISHED,
      "02": _common.CONN_SYN_SENT,
      "03": _common.CONN_SYN_RECV,
      "04": _common.CONN_FIN_WAIT1,
      "05": _common.CONN_FIN_WAIT2,
      "06": _common.CONN_TIME_WAIT,
      "07": _common.CONN_CLOSE,
      "08": _common.CONN_CLOSE_WAIT,
      "09": _common.CONN_LAST_ACK,
      "0A": _common.CONN_LISTEN,
      "0B": _common.CONN_CLOSING
  }
  
  # These objects get set on "import psutil" from the __init__.py
  # file, see: https://github.com/giampaolo/psutil/issues/1402
  NoSuchProcess = None
  ZombieProcess = None
  AccessDenied = None
  TimeoutExpired = None
  
  
  # =====================================================================
  # --- named tuples
  # =====================================================================
  
  
  # psutil.virtual_memory()
  svmem = namedtuple(
      'svmem', ['total', 'available', 'percent', 'used', 'free',
                'active', 'inactive', 'buffers', 'cached', 'shared', 'slab'])
  # psutil.disk_io_counters()
  sdiskio = namedtuple(
      'sdiskio', ['read_count', 'write_count',
                  'read_bytes', 'write_bytes',
                  'read_time', 'write_time',
                  'read_merged_count', 'write_merged_count',
                  'busy_time'])
  # psutil.Process().open_files()
  popenfile = namedtuple(
      'popenfile', ['path', 'fd', 'position', 'mode', 'flags'])
  # psutil.Process().memory_info()
  pmem = namedtuple('pmem', 'rss vms shared text lib data dirty')
  # psutil.Process().memory_full_info()
  pfullmem = namedtuple('pfullmem', pmem._fields + ('uss', 'pss', 'swap'))
  # psutil.Process().memory_maps(grouped=True)
  pmmap_grouped = namedtuple(
      'pmmap_grouped',
      ['path', 'rss', 'size', 'pss', 'shared_clean', 'shared_dirty',
       'private_clean', 'private_dirty', 'referenced', 'anonymous', 'swap'])
  # psutil.Process().memory_maps(grouped=False)
  pmmap_ext = namedtuple(
      'pmmap_ext', 'addr perms ' + ' '.join(pmmap_grouped._fields))
  # psutil.Process.io_counters()
  pio = namedtuple('pio', ['read_count', 'write_count',
                           'read_bytes', 'write_bytes',
                           'read_chars', 'write_chars'])
  # psutil.Process.cpu_times()
  pcputimes = namedtuple('pcputimes',
                         ['user', 'system', 'children_user', 'children_system',
                          'iowait'])
  
  
  # =====================================================================
  # --- utils
  # =====================================================================
  
  
  def readlink(path):
      """Wrapper around os.readlink()."""
      assert isinstance(path, basestring), path
      path = os.readlink(path)
      # readlink() might return paths containing null bytes ('\x00')
      # resulting in "TypeError: must be encoded string without NULL
      # bytes, not str" errors when the string is passed to other
      # fs-related functions (os.*, open(), ...).
      # Apparently everything after '\x00' is garbage (we can have
      # ' (deleted)', 'new' and possibly others), see:
      # https://github.com/giampaolo/psutil/issues/717
      path = path.split('\x00')[0]
      # Certain paths have ' (deleted)' appended. Usually this is
      # bogus as the file actually exists. Even if it doesn't we
      # don't care.
      if path.endswith(' (deleted)') and not path_exists_strict(path):
          path = path[:-10]
      return path
  
  
  def file_flags_to_mode(flags):
      """Convert file's open() flags into a readable string.
      Used by Process.open_files().
      """
      modes_map = {os.O_RDONLY: 'r', os.O_WRONLY: 'w', os.O_RDWR: 'w+'}
      mode = modes_map[flags & (os.O_RDONLY | os.O_WRONLY | os.O_RDWR)]
      if flags & os.O_APPEND:
          mode = mode.replace('w', 'a', 1)
      mode = mode.replace('w+', 'r+')
      # possible values: r, w, a, r+, a+
      return mode
  
  
  def is_storage_device(name):
      """Return True if the given name refers to a root device (e.g.
      "sda", "nvme0n1") as opposed to a logical partition (e.g.  "sda1",
      "nvme0n1p1"). If name is a virtual device (e.g. "loop1", "ram")
      return True.
      """
      # Readapted from iostat source code, see:
      # https://github.com/sysstat/sysstat/blob/
      #     97912938cd476645b267280069e83b1c8dc0e1c7/common.c#L208
      # Some devices may have a slash in their name (e.g. cciss/c0d0...).
      name = name.replace('/', '!')
      including_virtual = True
      if including_virtual:
          path = "/sys/block/%s" % name
      else:
          path = "/sys/block/%s/device" % name
      return os.access(path, os.F_OK)
  
  
  @memoize
  def set_scputimes_ntuple(procfs_path):
      """Set a namedtuple of variable fields depending on the CPU times
      available on this Linux kernel version which may be:
      (user, nice, system, idle, iowait, irq, softirq, [steal, [guest,
       [guest_nice]]])
      Used by cpu_times() function.
      """
      global scputimes
      with open_binary('%s/stat' % procfs_path) as f:
          values = f.readline().split()[1:]
      fields = ['user', 'nice', 'system', 'idle', 'iowait', 'irq', 'softirq']
      vlen = len(values)
      if vlen >= 8:
          # Linux >= 2.6.11
          fields.append('steal')
      if vlen >= 9:
          # Linux >= 2.6.24
          fields.append('guest')
      if vlen >= 10:
          # Linux >= 3.2.0
          fields.append('guest_nice')
      scputimes = namedtuple('scputimes', fields)
  
  
  def cat(fname, fallback=_DEFAULT, binary=True):
      """Return file content.
      fallback: the value returned in case the file does not exist or
                cannot be read
      binary: whether to open the file in binary or text mode.
      """
      try:
          with open_binary(fname) if binary else open_text(fname) as f:
              return f.read().strip()
      except (IOError, OSError):
          if fallback is not _DEFAULT:
              return fallback
          else:
              raise
  
  
  try:
      set_scputimes_ntuple("/proc")
  except Exception:
      # Don't want to crash at import time.
      traceback.print_exc()
      scputimes = namedtuple('scputimes', 'user system idle')(0.0, 0.0, 0.0)
  
  
  # =====================================================================
  # --- system memory
  # =====================================================================
  
  
  def calculate_avail_vmem(mems):
      """Fallback for kernels < 3.14 where /proc/meminfo does not provide
      "MemAvailable:" column, see:
      https://blog.famzah.net/2014/09/24/
      This code reimplements the algorithm outlined here:
      https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/
          commit/?id=34e431b0ae398fc54ea69ff85ec700722c9da773
  
      XXX: on recent kernels this calculation differs by ~1.5% than
      "MemAvailable:" as it's calculated slightly differently, see:
      https://gitlab.com/procps-ng/procps/issues/42
      https://github.com/famzah/linux-memavailable-procfs/issues/2
      It is still way more realistic than doing (free + cached) though.
      """
      # Fallback for very old distros. According to
      # https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/
      #     commit/?id=34e431b0ae398fc54ea69ff85ec700722c9da773
      # ...long ago "avail" was calculated as (free + cached).
      # We might fallback in such cases:
      # "Active(file)" not available: 2.6.28 / Dec 2008
      # "Inactive(file)" not available: 2.6.28 / Dec 2008
      # "SReclaimable:" not available: 2.6.19 / Nov 2006
      # /proc/zoneinfo not available: 2.6.13 / Aug 2005
      free = mems[b'MemFree:']
      fallback = free + mems.get(b"Cached:", 0)
      try:
          lru_active_file = mems[b'Active(file):']
          lru_inactive_file = mems[b'Inactive(file):']
          slab_reclaimable = mems[b'SReclaimable:']
      except KeyError:
          return fallback
      try:
          f = open_binary('%s/zoneinfo' % get_procfs_path())
      except IOError:
          return fallback  # kernel 2.6.13
  
      watermark_low = 0
      with f:
          for line in f:
              line = line.strip()
              if line.startswith(b'low'):
                  watermark_low += int(line.split()[1])
      watermark_low *= PAGESIZE
      watermark_low = watermark_low
  
      avail = free - watermark_low
      pagecache = lru_active_file + lru_inactive_file
      pagecache -= min(pagecache / 2, watermark_low)
      avail += pagecache
      avail += slab_reclaimable - min(slab_reclaimable / 2.0, watermark_low)
      return int(avail)
  
  
  def virtual_memory():
      """Report virtual memory stats.
      This implementation matches "free" and "vmstat -s" cmdline
      utility values and procps-ng-3.3.12 source was used as a reference
      (2016-09-18):
      https://gitlab.com/procps-ng/procps/blob/
          24fd2605c51fccc375ab0287cec33aa767f06718/proc/sysinfo.c
      For reference, procps-ng-3.3.10 is the version available on Ubuntu
      16.04.
  
      Note about "available" memory: up until psutil 4.3 it was
      calculated as "avail = (free + buffers + cached)". Now
      "MemAvailable:" column (kernel 3.14) from /proc/meminfo is used as
      it's more accurate.
      That matches "available" column in newer versions of "free".
      """
      missing_fields = []
      mems = {}
      with open_binary('%s/meminfo' % get_procfs_path()) as f:
          for line in f:
              fields = line.split()
              mems[fields[0]] = int(fields[1]) * 1024
  
      # /proc doc states that the available fields in /proc/meminfo vary
      # by architecture and compile options, but these 3 values are also
      # returned by sysinfo(2); as such we assume they are always there.
      total = mems[b'MemTotal:']
      free = mems[b'MemFree:']
      try:
          buffers = mems[b'Buffers:']
      except KeyError:
          # https://github.com/giampaolo/psutil/issues/1010
          buffers = 0
          missing_fields.append('buffers')
      try:
          cached = mems[b"Cached:"]
      except KeyError:
          cached = 0
          missing_fields.append('cached')
      else:
          # "free" cmdline utility sums reclaimable to cached.
          # Older versions of procps used to add slab memory instead.
          # This got changed in:
          # https://gitlab.com/procps-ng/procps/commit/
          #     05d751c4f076a2f0118b914c5e51cfbb4762ad8e
          cached += mems.get(b"SReclaimable:", 0)  # since kernel 2.6.19
  
      try:
          shared = mems[b'Shmem:']  # since kernel 2.6.32
      except KeyError:
          try:
              shared = mems[b'MemShared:']  # kernels 2.4
          except KeyError:
              shared = 0
              missing_fields.append('shared')
  
      try:
          active = mems[b"Active:"]
      except KeyError:
          active = 0
          missing_fields.append('active')
  
      try:
          inactive = mems[b"Inactive:"]
      except KeyError:
          try:
              inactive = \
                  mems[b"Inact_dirty:"] + \
                  mems[b"Inact_clean:"] + \
                  mems[b"Inact_laundry:"]
          except KeyError:
              inactive = 0
              missing_fields.append('inactive')
  
      try:
          slab = mems[b"Slab:"]
      except KeyError:
          slab = 0
  
      used = total - free - cached - buffers
      if used < 0:
          # May be symptomatic of running within a LCX container where such
          # values will be dramatically distorted over those of the host.
          used = total - free
  
      # - starting from 4.4.0 we match free's "available" column.
      #   Before 4.4.0 we calculated it as (free + buffers + cached)
      #   which matched htop.
      # - free and htop available memory differs as per:
      #   http://askubuntu.com/a/369589
      #   http://unix.stackexchange.com/a/65852/168884
      # - MemAvailable has been introduced in kernel 3.14
      try:
          avail = mems[b'MemAvailable:']
      except KeyError:
          avail = calculate_avail_vmem(mems)
  
      if avail < 0:
          avail = 0
          missing_fields.append('available')
  
      # If avail is greater than total or our calculation overflows,
      # that's symptomatic of running within a LCX container where such
      # values will be dramatically distorted over those of the host.
      # https://gitlab.com/procps-ng/procps/blob/
      #     24fd2605c51fccc375ab0287cec33aa767f06718/proc/sysinfo.c#L764
      if avail > total:
          avail = free
  
      percent = usage_percent((total - avail), total, round_=1)
  
      # Warn about missing metrics which are set to 0.
      if missing_fields:
          msg = "%s memory stats couldn't be determined and %s set to 0" % (
              ", ".join(missing_fields),
              "was" if len(missing_fields) == 1 else "were")
          warnings.warn(msg, RuntimeWarning)
  
      return svmem(total, avail, percent, used, free,
                   active, inactive, buffers, cached, shared, slab)
  
  
  def swap_memory():
      """Return swap memory metrics."""
      mems = {}
      with open_binary('%s/meminfo' % get_procfs_path()) as f:
          for line in f:
              fields = line.split()
              mems[fields[0]] = int(fields[1]) * 1024
      # We prefer /proc/meminfo over sysinfo() syscall so that
      # psutil.PROCFS_PATH can be used in order to allow retrieval
      # for linux containers, see:
      # https://github.com/giampaolo/psutil/issues/1015
      try:
          total = mems[b'SwapTotal:']
          free = mems[b'SwapFree:']
      except KeyError:
          _, _, _, _, total, free, unit_multiplier = cext.linux_sysinfo()
          total *= unit_multiplier
          free *= unit_multiplier
  
      used = total - free
      percent = usage_percent(used, total, round_=1)
      # get pgin/pgouts
      try:
          f = open_binary("%s/vmstat" % get_procfs_path())
      except IOError as err:
          # see https://github.com/giampaolo/psutil/issues/722
          msg = "'sin' and 'sout' swap memory stats couldn't " \
                "be determined and were set to 0 (%s)" % str(err)
          warnings.warn(msg, RuntimeWarning)
          sin = sout = 0
      else:
          with f:
              sin = sout = None
              for line in f:
                  # values are expressed in 4 kilo bytes, we want
                  # bytes instead
                  if line.startswith(b'pswpin'):
                      sin = int(line.split(b' ')[1]) * 4 * 1024
                  elif line.startswith(b'pswpout'):
                      sout = int(line.split(b' ')[1]) * 4 * 1024
                  if sin is not None and sout is not None:
                      break
              else:
                  # we might get here when dealing with exotic Linux
                  # flavors, see:
                  # https://github.com/giampaolo/psutil/issues/313
                  msg = "'sin' and 'sout' swap memory stats couldn't " \
                        "be determined and were set to 0"
                  warnings.warn(msg, RuntimeWarning)
                  sin = sout = 0
      return _common.sswap(total, used, free, percent, sin, sout)
  
  
  # =====================================================================
  # --- CPU
  # =====================================================================
  
  
  def cpu_times():
      """Return a named tuple representing the following system-wide
      CPU times:
      (user, nice, system, idle, iowait, irq, softirq [steal, [guest,
       [guest_nice]]])
      Last 3 fields may not be available on all Linux kernel versions.
      """
      procfs_path = get_procfs_path()
      set_scputimes_ntuple(procfs_path)
      with open_binary('%s/stat' % procfs_path) as f:
          values = f.readline().split()
      fields = values[1:len(scputimes._fields) + 1]
      fields = [float(x) / CLOCK_TICKS for x in fields]
      return scputimes(*fields)
  
  
  def per_cpu_times():
      """Return a list of namedtuple representing the CPU times
      for every CPU available on the system.
      """
      procfs_path = get_procfs_path()
      set_scputimes_ntuple(procfs_path)
      cpus = []
      with open_binary('%s/stat' % procfs_path) as f:
          # get rid of the first line which refers to system wide CPU stats
          f.readline()
          for line in f:
              if line.startswith(b'cpu'):
                  values = line.split()
                  fields = values[1:len(scputimes._fields) + 1]
                  fields = [float(x) / CLOCK_TICKS for x in fields]
                  entry = scputimes(*fields)
                  cpus.append(entry)
          return cpus
  
  
  def cpu_count_logical():
      """Return the number of logical CPUs in the system."""
      try:
          return os.sysconf("SC_NPROCESSORS_ONLN")
      except ValueError:
          # as a second fallback we try to parse /proc/cpuinfo
          num = 0
          with open_binary('%s/cpuinfo' % get_procfs_path()) as f:
              for line in f:
                  if line.lower().startswith(b'processor'):
                      num += 1
  
          # unknown format (e.g. amrel/sparc architectures), see:
          # https://github.com/giampaolo/psutil/issues/200
          # try to parse /proc/stat as a last resort
          if num == 0:
              search = re.compile(r'cpu\d')
              with open_text('%s/stat' % get_procfs_path()) as f:
                  for line in f:
                      line = line.split(' ')[0]
                      if search.match(line):
                          num += 1
  
          if num == 0:
              # mimic os.cpu_count()
              return None
          return num
  
  
  def cpu_count_physical():
      """Return the number of physical cores in the system."""
      # Method #1
      core_ids = set()
      for path in glob.glob(
              "/sys/devices/system/cpu/cpu[0-9]*/topology/core_id"):
          with open_binary(path) as f:
              core_ids.add(int(f.read()))
      result = len(core_ids)
      if result != 0:
          return result
  
      # Method #2
      mapping = {}
      current_info = {}
      with open_binary('%s/cpuinfo' % get_procfs_path()) as f:
          for line in f:
              line = line.strip().lower()
              if not line:
                  # new section
                  if (b'physical id' in current_info and
                          b'cpu cores' in current_info):
                      mapping[current_info[b'physical id']] = \
                          current_info[b'cpu cores']
                  current_info = {}
              else:
                  # ongoing section
                  if (line.startswith(b'physical id') or
                          line.startswith(b'cpu cores')):
                      key, value = line.split(b'\t:', 1)
                      current_info[key] = int(value)
  
      result = sum(mapping.values())
      return result or None  # mimic os.cpu_count()
  
  
  def cpu_stats():
      """Return various CPU stats as a named tuple."""
      with open_binary('%s/stat' % get_procfs_path()) as f:
          ctx_switches = None
          interrupts = None
          soft_interrupts = None
          for line in f:
              if line.startswith(b'ctxt'):
                  ctx_switches = int(line.split()[1])
              elif line.startswith(b'intr'):
                  interrupts = int(line.split()[1])
              elif line.startswith(b'softirq'):
                  soft_interrupts = int(line.split()[1])
              if ctx_switches is not None and soft_interrupts is not None \
                      and interrupts is not None:
                  break
      syscalls = 0
      return _common.scpustats(
          ctx_switches, interrupts, soft_interrupts, syscalls)
  
  
  if os.path.exists("/sys/devices/system/cpu/cpufreq/policy0") or \
          os.path.exists("/sys/devices/system/cpu/cpu0/cpufreq"):
      def cpu_freq():
          """Return frequency metrics for all CPUs.
          Contrarily to other OSes, Linux updates these values in
          real-time.
          """
          def get_path(num):
              for p in ("/sys/devices/system/cpu/cpufreq/policy%s" % num,
                        "/sys/devices/system/cpu/cpu%s/cpufreq" % num):
                  if os.path.exists(p):
                      return p
  
          ret = []
          for n in range(cpu_count_logical()):
              path = get_path(n)
              if not path:
                  continue
  
              pjoin = os.path.join
              curr = cat(pjoin(path, "scaling_cur_freq"), fallback=None)
              if curr is None:
                  # Likely an old RedHat, see:
                  # https://github.com/giampaolo/psutil/issues/1071
                  curr = cat(pjoin(path, "cpuinfo_cur_freq"), fallback=None)
                  if curr is None:
                      raise NotImplementedError(
                          "can't find current frequency file")
              curr = int(curr) / 1000
              max_ = int(cat(pjoin(path, "scaling_max_freq"))) / 1000
              min_ = int(cat(pjoin(path, "scaling_min_freq"))) / 1000
              ret.append(_common.scpufreq(curr, min_, max_))
          return ret
  
  elif os.path.exists("/proc/cpuinfo"):
      def cpu_freq():
          """Alternate implementation using /proc/cpuinfo.
          min and max frequencies are not available and are set to None.
          """
          ret = []
          with open_binary('%s/cpuinfo' % get_procfs_path()) as f:
              for line in f:
                  if line.lower().startswith(b'cpu mhz'):
                      key, value = line.split(b'\t:', 1)
                      ret.append(_common.scpufreq(float(value), 0., 0.))
          return ret
  
  else:
      def cpu_freq():
          """Dummy implementation when none of the above files are present.
          """
          return []
  
  
  # =====================================================================
  # --- network
  # =====================================================================
  
  
  net_if_addrs = cext_posix.net_if_addrs
  
  
  class _Ipv6UnsupportedError(Exception):
      pass
  
  
  class Connections:
      """A wrapper on top of /proc/net/* files, retrieving per-process
      and system-wide open connections (TCP, UDP, UNIX) similarly to
      "netstat -an".
  
      Note: in case of UNIX sockets we're only able to determine the
      local endpoint/path, not the one it's connected to.
      According to [1] it would be possible but not easily.
  
      [1] http://serverfault.com/a/417946
      """
  
      def __init__(self):
          tcp4 = ("tcp", socket.AF_INET, socket.SOCK_STREAM)
          tcp6 = ("tcp6", socket.AF_INET6, socket.SOCK_STREAM)
          udp4 = ("udp", socket.AF_INET, socket.SOCK_DGRAM)
          udp6 = ("udp6", socket.AF_INET6, socket.SOCK_DGRAM)
          unix = ("unix", socket.AF_UNIX, None)
          self.tmap = {
              "all": (tcp4, tcp6, udp4, udp6, unix),
              "tcp": (tcp4, tcp6),
              "tcp4": (tcp4,),
              "tcp6": (tcp6,),
              "udp": (udp4, udp6),
              "udp4": (udp4,),
              "udp6": (udp6,),
              "unix": (unix,),
              "inet": (tcp4, tcp6, udp4, udp6),
              "inet4": (tcp4, udp4),
              "inet6": (tcp6, udp6),
          }
          self._procfs_path = None
  
      def get_proc_inodes(self, pid):
          inodes = defaultdict(list)
          for fd in os.listdir("%s/%s/fd" % (self._procfs_path, pid)):
              try:
                  inode = readlink("%s/%s/fd/%s" % (self._procfs_path, pid, fd))
              except (FileNotFoundError, ProcessLookupError):
                  # ENOENT == file which is gone in the meantime;
                  # os.stat('/proc/%s' % self.pid) will be done later
                  # to force NSP (if it's the case)
                  continue
              except OSError as err:
                  if err.errno == errno.EINVAL:
                      # not a link
                      continue
                  raise
              else:
                  if inode.startswith('socket:['):
                      # the process is using a socket
                      inode = inode[8:][:-1]
                      inodes[inode].append((pid, int(fd)))
          return inodes
  
      def get_all_inodes(self):
          inodes = {}
          for pid in pids():
              try:
                  inodes.update(self.get_proc_inodes(pid))
              except (FileNotFoundError, ProcessLookupError, PermissionError):
                  # os.listdir() is gonna raise a lot of access denied
                  # exceptions in case of unprivileged user; that's fine
                  # as we'll just end up returning a connection with PID
                  # and fd set to None anyway.
                  # Both netstat -an and lsof does the same so it's
                  # unlikely we can do any better.
                  # ENOENT just means a PID disappeared on us.
                  continue
          return inodes
  
      @staticmethod
      def decode_address(addr, family):
          """Accept an "ip:port" address as displayed in /proc/net/*
          and convert it into a human readable form, like:
  
          "0500000A:0016" -> ("10.0.0.5", 22)
          "0000000000000000FFFF00000100007F:9E49" -> ("::ffff:127.0.0.1", 40521)
  
          The IP address portion is a little or big endian four-byte
          hexadecimal number; that is, the least significant byte is listed
          first, so we need to reverse the order of the bytes to convert it
          to an IP address.
          The port is represented as a two-byte hexadecimal number.
  
          Reference:
          http://linuxdevcenter.com/pub/a/linux/2000/11/16/LinuxAdmin.html
          """
          ip, port = addr.split(':')
          port = int(port, 16)
          # this usually refers to a local socket in listen mode with
          # no end-points connected
          if not port:
              return ()
          if PY3:
              ip = ip.encode('ascii')
          if family == socket.AF_INET:
              # see: https://github.com/giampaolo/psutil/issues/201
              if LITTLE_ENDIAN:
                  ip = socket.inet_ntop(family, base64.b16decode(ip)[::-1])
              else:
                  ip = socket.inet_ntop(family, base64.b16decode(ip))
          else:  # IPv6
              # old version - let's keep it, just in case...
              # ip = ip.decode('hex')
              # return socket.inet_ntop(socket.AF_INET6,
              #          ''.join(ip[i:i+4][::-1] for i in xrange(0, 16, 4)))
              ip = base64.b16decode(ip)
              try:
                  # see: https://github.com/giampaolo/psutil/issues/201
                  if LITTLE_ENDIAN:
                      ip = socket.inet_ntop(
                          socket.AF_INET6,
                          struct.pack('>4I', *struct.unpack('<4I', ip)))
                  else:
                      ip = socket.inet_ntop(
                          socket.AF_INET6,
                          struct.pack('<4I', *struct.unpack('<4I', ip)))
              except ValueError:
                  # see: https://github.com/giampaolo/psutil/issues/623
                  if not supports_ipv6():
                      raise _Ipv6UnsupportedError
                  else:
                      raise
          return _common.addr(ip, port)
  
      @staticmethod
      def process_inet(file, family, type_, inodes, filter_pid=None):
          """Parse /proc/net/tcp* and /proc/net/udp* files."""
          if file.endswith('6') and not os.path.exists(file):
              # IPv6 not supported
              return
          with open_text(file, buffering=BIGFILE_BUFFERING) as f:
              f.readline()  # skip the first line
              for lineno, line in enumerate(f, 1):
                  try:
                      _, laddr, raddr, status, _, _, _, _, _, inode = \
                          line.split()[:10]
                  except ValueError:
                      raise RuntimeError(
                          "error while parsing %s; malformed line %s %r" % (
                              file, lineno, line))
                  if inode in inodes:
                      # # We assume inet sockets are unique, so we error
                      # # out if there are multiple references to the
                      # # same inode. We won't do this for UNIX sockets.
                      # if len(inodes[inode]) > 1 and family != socket.AF_UNIX:
                      #     raise ValueError("ambiguos inode with multiple "
                      #                      "PIDs references")
                      pid, fd = inodes[inode][0]
                  else:
                      pid, fd = None, -1
                  if filter_pid is not None and filter_pid != pid:
                      continue
                  else:
                      if type_ == socket.SOCK_STREAM:
                          status = TCP_STATUSES[status]
                      else:
                          status = _common.CONN_NONE
                      try:
                          laddr = Connections.decode_address(laddr, family)
                          raddr = Connections.decode_address(raddr, family)
                      except _Ipv6UnsupportedError:
                          continue
                      yield (fd, family, type_, laddr, raddr, status, pid)
  
      @staticmethod
      def process_unix(file, family, inodes, filter_pid=None):
          """Parse /proc/net/unix files."""
          with open_text(file, buffering=BIGFILE_BUFFERING) as f:
              f.readline()  # skip the first line
              for line in f:
                  tokens = line.split()
                  try:
                      _, _, _, _, type_, _, inode = tokens[0:7]
                  except ValueError:
                      if ' ' not in line:
                          # see: https://github.com/giampaolo/psutil/issues/766
                          continue
                      raise RuntimeError(
                          "error while parsing %s; malformed line %r" % (
                              file, line))
                  if inode in inodes:
                      # With UNIX sockets we can have a single inode
                      # referencing many file descriptors.
                      pairs = inodes[inode]
                  else:
                      pairs = [(None, -1)]
                  for pid, fd in pairs:
                      if filter_pid is not None and filter_pid != pid:
                          continue
                      else:
                          if len(tokens) == 8:
                              path = tokens[-1]
                          else:
                              path = ""
                          type_ = _common.socktype_to_enum(int(type_))
                          # XXX: determining the remote endpoint of a
                          # UNIX socket on Linux is not possible, see:
                          # https://serverfault.com/questions/252723/
                          raddr = ""
                          status = _common.CONN_NONE
                          yield (fd, family, type_, path, raddr, status, pid)
  
      def retrieve(self, kind, pid=None):
          if kind not in self.tmap:
              raise ValueError("invalid %r kind argument; choose between %s"
                               % (kind, ', '.join([repr(x) for x in self.tmap])))
          self._procfs_path = get_procfs_path()
          if pid is not None:
              inodes = self.get_proc_inodes(pid)
              if not inodes:
                  # no connections for this process
                  return []
          else:
              inodes = self.get_all_inodes()
          ret = set()
          for f, family, type_ in self.tmap[kind]:
              if family in (socket.AF_INET, socket.AF_INET6):
                  ls = self.process_inet(
                      "%s/net/%s" % (self._procfs_path, f),
                      family, type_, inodes, filter_pid=pid)
              else:
                  ls = self.process_unix(
                      "%s/net/%s" % (self._procfs_path, f),
                      family, inodes, filter_pid=pid)
              for fd, family, type_, laddr, raddr, status, bound_pid in ls:
                  if pid:
                      conn = _common.pconn(fd, family, type_, laddr, raddr,
                                           status)
                  else:
                      conn = _common.sconn(fd, family, type_, laddr, raddr,
                                           status, bound_pid)
                  ret.add(conn)
          return list(ret)
  
  
  _connections = Connections()
  
  
  def net_connections(kind='inet'):
      """Return system-wide open connections."""
      return _connections.retrieve(kind)
  
  
  def net_io_counters():
      """Return network I/O statistics for every network interface
      installed on the system as a dict of raw tuples.
      """
      with open_text("%s/net/dev" % get_procfs_path()) as f:
          lines = f.readlines()
      retdict = {}
      for line in lines[2:]:
          colon = line.rfind(':')
          assert colon > 0, repr(line)
          name = line[:colon].strip()
          fields = line[colon + 1:].strip().split()
  
          # in
          (bytes_recv,
           packets_recv,
           errin,
           dropin,
           fifoin,  # unused
           framein,  # unused
           compressedin,  # unused
           multicastin,  # unused
           # out
           bytes_sent,
           packets_sent,
           errout,
           dropout,
           fifoout,  # unused
           collisionsout,  # unused
           carrierout,  # unused
           compressedout) = map(int, fields)
  
          retdict[name] = (bytes_sent, bytes_recv, packets_sent, packets_recv,
                           errin, errout, dropin, dropout)
      return retdict
  
  
  def net_if_stats():
      """Get NIC stats (isup, duplex, speed, mtu)."""
      duplex_map = {cext.DUPLEX_FULL: NIC_DUPLEX_FULL,
                    cext.DUPLEX_HALF: NIC_DUPLEX_HALF,
                    cext.DUPLEX_UNKNOWN: NIC_DUPLEX_UNKNOWN}
      names = net_io_counters().keys()
      ret = {}
      for name in names:
          try:
              mtu = cext_posix.net_if_mtu(name)
              isup = cext_posix.net_if_flags(name)
              duplex, speed = cext.net_if_duplex_speed(name)
          except OSError as err:
              # https://github.com/giampaolo/psutil/issues/1279
              if err.errno != errno.ENODEV:
                  raise
          else:
              ret[name] = _common.snicstats(isup, duplex_map[duplex], speed, mtu)
      return ret
  
  
  # =====================================================================
  # --- disks
  # =====================================================================
  
  
  disk_usage = _psposix.disk_usage
  
  
  def disk_io_counters(perdisk=False):
      """Return disk I/O statistics for every disk installed on the
      system as a dict of raw tuples.
      """
      def read_procfs():
          # OK, this is a bit confusing. The format of /proc/diskstats can
          # have 3 variations.
          # On Linux 2.4 each line has always 15 fields, e.g.:
          # "3     0   8 hda 8 8 8 8 8 8 8 8 8 8 8"
          # On Linux 2.6+ each line *usually* has 14 fields, and the disk
          # name is in another position, like this:
          # "3    0   hda 8 8 8 8 8 8 8 8 8 8 8"
          # ...unless (Linux 2.6) the line refers to a partition instead
          # of a disk, in which case the line has less fields (7):
          # "3    1   hda1 8 8 8 8"
          # 4.18+ has 4 fields added:
          # "3    0   hda 8 8 8 8 8 8 8 8 8 8 8 0 0 0 0"
          # See:
          # https://www.kernel.org/doc/Documentation/iostats.txt
          # https://www.kernel.org/doc/Documentation/ABI/testing/procfs-diskstats
          with open_text("%s/diskstats" % get_procfs_path()) as f:
              lines = f.readlines()
          for line in lines:
              fields = line.split()
              flen = len(fields)
              if flen == 15:
                  # Linux 2.4
                  name = fields[3]
                  reads = int(fields[2])
                  (reads_merged, rbytes, rtime, writes, writes_merged,
                      wbytes, wtime, _, busy_time, _) = map(int, fields[4:14])
              elif flen == 14 or flen == 18:
                  # Linux 2.6+, line referring to a disk
                  name = fields[2]
                  (reads, reads_merged, rbytes, rtime, writes, writes_merged,
                      wbytes, wtime, _, busy_time, _) = map(int, fields[3:14])
              elif flen == 7:
                  # Linux 2.6+, line referring to a partition
                  name = fields[2]
                  reads, rbytes, writes, wbytes = map(int, fields[3:])
                  rtime = wtime = reads_merged = writes_merged = busy_time = 0
              else:
                  raise ValueError("not sure how to interpret line %r" % line)
              yield (name, reads, writes, rbytes, wbytes, rtime, wtime,
                     reads_merged, writes_merged, busy_time)
  
      def read_sysfs():
          for block in os.listdir('/sys/block'):
              for root, _, files in os.walk(os.path.join('/sys/block', block)):
                  if 'stat' not in files:
                      continue
                  with open_text(os.path.join(root, 'stat')) as f:
                      fields = f.read().strip().split()
                  name = os.path.basename(root)
                  (reads, reads_merged, rbytes, rtime, writes, writes_merged,
                      wbytes, wtime, _, busy_time, _) = map(int, fields)
                  yield (name, reads, writes, rbytes, wbytes, rtime,
                         wtime, reads_merged, writes_merged, busy_time)
  
      if os.path.exists('%s/diskstats' % get_procfs_path()):
          gen = read_procfs()
      elif os.path.exists('/sys/block'):
          gen = read_sysfs()
      else:
          raise NotImplementedError(
              "%s/diskstats nor /sys/block filesystem are available on this "
              "system" % get_procfs_path())
  
      retdict = {}
      for entry in gen:
          (name, reads, writes, rbytes, wbytes, rtime, wtime, reads_merged,
              writes_merged, busy_time) = entry
          if not perdisk and not is_storage_device(name):
              # perdisk=False means we want to calculate totals so we skip
              # partitions (e.g. 'sda1', 'nvme0n1p1') and only include
              # base disk devices (e.g. 'sda', 'nvme0n1'). Base disks
              # include a total of all their partitions + some extra size
              # of their own:
              #     $ cat /proc/diskstats
              #     259       0 sda 10485760 ...
              #     259       1 sda1 5186039 ...
              #     259       1 sda2 5082039 ...
              # See:
              # https://github.com/giampaolo/psutil/pull/1313
              continue
  
          rbytes *= DISK_SECTOR_SIZE
          wbytes *= DISK_SECTOR_SIZE
          retdict[name] = (reads, writes, rbytes, wbytes, rtime, wtime,
                           reads_merged, writes_merged, busy_time)
  
      return retdict
  
  
  def disk_partitions(all=False):
      """Return mounted disk partitions as a list of namedtuples."""
      fstypes = set()
      procfs_path = get_procfs_path()
      with open_text("%s/filesystems" % procfs_path) as f:
          for line in f:
              line = line.strip()
              if not line.startswith("nodev"):
                  fstypes.add(line.strip())
              else:
                  # ignore all lines starting with "nodev" except "nodev zfs"
                  fstype = line.split("\t")[1]
                  if fstype == "zfs":
                      fstypes.add("zfs")
  
      # See: https://github.com/giampaolo/psutil/issues/1307
      if procfs_path == "/proc" and os.path.isfile('/etc/mtab'):
          mounts_path = os.path.realpath("/etc/mtab")
      else:
          mounts_path = os.path.realpath("%s/self/mounts" % procfs_path)
  
      retlist = []
      partitions = cext.disk_partitions(mounts_path)
      for partition in partitions:
          device, mountpoint, fstype, opts = partition
          if device == 'none':
              device = ''
          if not all:
              if device == '' or fstype not in fstypes:
                  continue
          ntuple = _common.sdiskpart(device, mountpoint, fstype, opts)
          retlist.append(ntuple)
      return retlist
  
  
  # =====================================================================
  # --- sensors
  # =====================================================================
  
  
  def sensors_temperatures():
      """Return hardware (CPU and others) temperatures as a dict
      including hardware name, label, current, max and critical
      temperatures.
  
      Implementation notes:
      - /sys/class/hwmon looks like the most recent interface to
        retrieve this info, and this implementation relies on it
        only (old distros will probably use something else)
      - lm-sensors on Ubuntu 16.04 relies on /sys/class/hwmon
      - /sys/class/thermal/thermal_zone* is another one but it's more
        difficult to parse
      """
      ret = collections.defaultdict(list)
      basenames = glob.glob('/sys/class/hwmon/hwmon*/temp*_*')
      # CentOS has an intermediate /device directory:
      # https://github.com/giampaolo/psutil/issues/971
      # https://github.com/nicolargo/glances/issues/1060
      basenames.extend(glob.glob('/sys/class/hwmon/hwmon*/device/temp*_*'))
      basenames = sorted(set([x.split('_')[0] for x in basenames]))
  
      for base in basenames:
          try:
              path = base + '_input'
              current = float(cat(path)) / 1000.0
              path = os.path.join(os.path.dirname(base), 'name')
              unit_name = cat(path, binary=False)
          except (IOError, OSError, ValueError) as err:
              # A lot of things can go wrong here, so let's just skip the
              # whole entry. Sure thing is Linux's /sys/class/hwmon really
              # is a stinky broken mess.
              # https://github.com/giampaolo/psutil/issues/1009
              # https://github.com/giampaolo/psutil/issues/1101
              # https://github.com/giampaolo/psutil/issues/1129
              # https://github.com/giampaolo/psutil/issues/1245
              # https://github.com/giampaolo/psutil/issues/1323
              warnings.warn("ignoring %r for file %r" % (err, path),
                            RuntimeWarning)
              continue
  
          high = cat(base + '_max', fallback=None)
          critical = cat(base + '_crit', fallback=None)
          label = cat(base + '_label', fallback='', binary=False)
  
          if high is not None:
              try:
                  high = float(high) / 1000.0
              except ValueError:
                  high = None
          if critical is not None:
              try:
                  critical = float(critical) / 1000.0
              except ValueError:
                  critical = None
  
          ret[unit_name].append((label, current, high, critical))
  
      # Indication that no sensors were detected in /sys/class/hwmon/
      if not basenames:
          basenames = glob.glob('/sys/class/thermal/thermal_zone*')
          basenames = sorted(set(basenames))
  
          for base in basenames:
              try:
                  path = os.path.join(base, 'temp')
                  current = float(cat(path)) / 1000.0
                  path = os.path.join(base, 'type')
                  unit_name = cat(path, binary=False)
              except (IOError, OSError, ValueError) as err:
                  warnings.warn("ignoring %r for file %r" % (err, path),
                                RuntimeWarning)
                  continue
  
              trip_paths = glob.glob(base + '/trip_point*')
              trip_points = set(['_'.join(
                  os.path.basename(p).split('_')[0:3]) for p in trip_paths])
              critical = None
              high = None
              for trip_point in trip_points:
                  path = os.path.join(base, trip_point + "_type")
                  trip_type = cat(path, fallback='', binary=False)
                  if trip_type == 'critical':
                      critical = cat(os.path.join(base, trip_point + "_temp"),
                                     fallback=None)
                  elif trip_type == 'high':
                      high = cat(os.path.join(base, trip_point + "_temp"),
                                 fallback=None)
  
                  if high is not None:
                      try:
                          high = float(high) / 1000.0
                      except ValueError:
                          high = None
                  if critical is not None:
                      try:
                          critical = float(critical) / 1000.0
                      except ValueError:
                          critical = None
  
              ret[unit_name].append(('', current, high, critical))
  
      return dict(ret)
  
  
  def sensors_fans():
      """Return hardware fans info (for CPU and other peripherals) as a
      dict including hardware label and current speed.
  
      Implementation notes:
      - /sys/class/hwmon looks like the most recent interface to
        retrieve this info, and this implementation relies on it
        only (old distros will probably use something else)
      - lm-sensors on Ubuntu 16.04 relies on /sys/class/hwmon
      """
      ret = collections.defaultdict(list)
      basenames = glob.glob('/sys/class/hwmon/hwmon*/fan*_*')
      if not basenames:
          # CentOS has an intermediate /device directory:
          # https://github.com/giampaolo/psutil/issues/971
          basenames = glob.glob('/sys/class/hwmon/hwmon*/device/fan*_*')
  
      basenames = sorted(set([x.split('_')[0] for x in basenames]))
      for base in basenames:
          try:
              current = int(cat(base + '_input'))
          except (IOError, OSError) as err:
              warnings.warn("ignoring %r" % err, RuntimeWarning)
              continue
          unit_name = cat(os.path.join(os.path.dirname(base), 'name'),
                          binary=False)
          label = cat(base + '_label', fallback='', binary=False)
          ret[unit_name].append(_common.sfan(label, current))
  
      return dict(ret)
  
  
  def sensors_battery():
      """Return battery information.
      Implementation note: it appears /sys/class/power_supply/BAT0/
      directory structure may vary and provide files with the same
      meaning but under different names, see:
      https://github.com/giampaolo/psutil/issues/966
      """
      null = object()
  
      def multi_cat(*paths):
          """Attempt to read the content of multiple files which may
          not exist. If none of them exist return None.
          """
          for path in paths:
              ret = cat(path, fallback=null)
              if ret != null:
                  return int(ret) if ret.isdigit() else ret
          return None
  
      bats = [x for x in os.listdir(POWER_SUPPLY_PATH) if x.startswith('BAT')]
      if not bats:
          return None
      # Get the first available battery. Usually this is "BAT0", except
      # some rare exceptions:
      # https://github.com/giampaolo/psutil/issues/1238
      root = os.path.join(POWER_SUPPLY_PATH, sorted(bats)[0])
  
      # Base metrics.
      energy_now = multi_cat(
          root + "/energy_now",
          root + "/charge_now")
      power_now = multi_cat(
          root + "/power_now",
          root + "/current_now")
      energy_full = multi_cat(
          root + "/energy_full",
          root + "/charge_full")
      if energy_now is None or power_now is None:
          return None
  
      # Percent. If we have energy_full the percentage will be more
      # accurate compared to reading /capacity file (float vs. int).
      if energy_full is not None:
          try:
              percent = 100.0 * energy_now / energy_full
          except ZeroDivisionError:
              percent = 0.0
      else:
          percent = int(cat(root + "/capacity", fallback=-1))
          if percent == -1:
              return None
  
      # Is AC power cable plugged in?
      # Note: AC0 is not always available and sometimes (e.g. CentOS7)
      # it's called "AC".
      power_plugged = None
      online = multi_cat(
          os.path.join(POWER_SUPPLY_PATH, "AC0/online"),
          os.path.join(POWER_SUPPLY_PATH, "AC/online"))
      if online is not None:
          power_plugged = online == 1
      else:
          status = cat(root + "/status", fallback="", binary=False).lower()
          if status == "discharging":
              power_plugged = False
          elif status in ("charging", "full"):
              power_plugged = True
  
      # Seconds left.
      # Note to self: we may also calculate the charging ETA as per:
      # https://github.com/thialfihar/dotfiles/blob/
      #     013937745fd9050c30146290e8f963d65c0179e6/bin/battery.py#L55
      if power_plugged:
          secsleft = _common.POWER_TIME_UNLIMITED
      else:
          try:
              secsleft = int(energy_now / power_now * 3600)
          except ZeroDivisionError:
              secsleft = _common.POWER_TIME_UNKNOWN
  
      return _common.sbattery(percent, secsleft, power_plugged)
  
  
  # =====================================================================
  # --- other system functions
  # =====================================================================
  
  
  def users():
      """Return currently connected users as a list of namedtuples."""
      retlist = []
      rawlist = cext.users()
      for item in rawlist:
          user, tty, hostname, tstamp, user_process, pid = item
          # note: the underlying C function includes entries about
          # system boot, run level and others.  We might want
          # to use them in the future.
          if not user_process:
              continue
          if hostname in (':0.0', ':0'):
              hostname = 'localhost'
          nt = _common.suser(user, tty or None, hostname, tstamp, pid)
          retlist.append(nt)
      return retlist
  
  
  def boot_time():
      """Return the system boot time expressed in seconds since the epoch."""
      global BOOT_TIME
      path = '%s/stat' % get_procfs_path()
      with open_binary(path) as f:
          for line in f:
              if line.startswith(b'btime'):
                  ret = float(line.strip().split()[1])
                  BOOT_TIME = ret
                  return ret
          raise RuntimeError(
              "line 'btime' not found in %s" % path)
  
  
  # =====================================================================
  # --- processes
  # =====================================================================
  
  
  def pids():
      """Returns a list of PIDs currently running on the system."""
      return [int(x) for x in os.listdir(b(get_procfs_path())) if x.isdigit()]
  
  
  def pid_exists(pid):
      """Check for the existence of a unix PID. Linux TIDs are not
      supported (always return False).
      """
      if not _psposix.pid_exists(pid):
          return False
      else:
          # Linux's apparently does not distinguish between PIDs and TIDs
          # (thread IDs).
          # listdir("/proc") won't show any TID (only PIDs) but
          # os.stat("/proc/{tid}") will succeed if {tid} exists.
          # os.kill() can also be passed a TID. This is quite confusing.
          # In here we want to enforce this distinction and support PIDs
          # only, see:
          # https://github.com/giampaolo/psutil/issues/687
          try:
              # Note: already checked that this is faster than using a
              # regular expr. Also (a lot) faster than doing
              # 'return pid in pids()'
              path = "%s/%s/status" % (get_procfs_path(), pid)
              with open_binary(path) as f:
                  for line in f:
                      if line.startswith(b"Tgid:"):
                          tgid = int(line.split()[1])
                          # If tgid and pid are the same then we're
                          # dealing with a process PID.
                          return tgid == pid
                  raise ValueError("'Tgid' line not found in %s" % path)
          except (EnvironmentError, ValueError):
              return pid in pids()
  
  
  def ppid_map():
      """Obtain a {pid: ppid, ...} dict for all running processes in
      one shot. Used to speed up Process.children().
      """
      ret = {}
      procfs_path = get_procfs_path()
      for pid in pids():
          try:
              with open_binary("%s/%s/stat" % (procfs_path, pid)) as f:
                  data = f.read()
          except (FileNotFoundError, ProcessLookupError):
              # Note: we should be able to access /stat for all processes
              # aka it's unlikely we'll bump into EPERM, which is good.
              pass
          else:
              rpar = data.rfind(b')')
              dset = data[rpar + 2:].split()
              ppid = int(dset[1])
              ret[pid] = ppid
      return ret
  
  
  def wrap_exceptions(fun):
      """Decorator which translates bare OSError and IOError exceptions
      into NoSuchProcess and AccessDenied.
      """
      @functools.wraps(fun)
      def wrapper(self, *args, **kwargs):
          try:
              return fun(self, *args, **kwargs)
          except PermissionError:
              raise AccessDenied(self.pid, self._name)
          except ProcessLookupError:
              raise NoSuchProcess(self.pid, self._name)
          except FileNotFoundError:
              if not os.path.exists("%s/%s" % (self._procfs_path, self.pid)):
                  raise NoSuchProcess(self.pid, self._name)
              # Note: zombies will keep existing under /proc until they're
              # gone so there's no way to distinguish them in here.
              raise
      return wrapper
  
  
  class Process(object):
      """Linux process implementation."""
  
      __slots__ = ["pid", "_name", "_ppid", "_procfs_path", "_cache"]
  
      def __init__(self, pid):
          self.pid = pid
          self._name = None
          self._ppid = None
          self._procfs_path = get_procfs_path()
  
      def _assert_alive(self):
          """Raise NSP if the process disappeared on us."""
          # For those C function who do not raise NSP, possibly returning
          # incorrect or incomplete result.
          os.stat('%s/%s' % (self._procfs_path, self.pid))
  
      @wrap_exceptions
      @memoize_when_activated
      def _parse_stat_file(self):
          """Parse /proc/{pid}/stat file and return a dict with various
          process info.
          Using "man proc" as a reference: where "man proc" refers to
          position N always substract 3 (e.g ppid position 4 in
          'man proc' == position 1 in here).
          The return value is cached in case oneshot() ctx manager is
          in use.
          """
          with open_binary("%s/%s/stat" % (self._procfs_path, self.pid)) as f:
              data = f.read()
          # Process name is between parentheses. It can contain spaces and
          # other parentheses. This is taken into account by looking for
          # the first occurrence of "(" and the last occurence of ")".
          rpar = data.rfind(b')')
          name = data[data.find(b'(') + 1:rpar]
          fields = data[rpar + 2:].split()
  
          ret = {}
          ret['name'] = name
          ret['status'] = fields[0]
          ret['ppid'] = fields[1]
          ret['ttynr'] = fields[4]
          ret['utime'] = fields[11]
          ret['stime'] = fields[12]
          ret['children_utime'] = fields[13]
          ret['children_stime'] = fields[14]
          ret['create_time'] = fields[19]
          ret['cpu_num'] = fields[36]
          ret['blkio_ticks'] = fields[39]  # aka 'delayacct_blkio_ticks'
  
          return ret
  
      @wrap_exceptions
      @memoize_when_activated
      def _read_status_file(self):
          """Read /proc/{pid}/stat file and return its content.
          The return value is cached in case oneshot() ctx manager is
          in use.
          """
          with open_binary("%s/%s/status" % (self._procfs_path, self.pid)) as f:
              return f.read()
  
      @wrap_exceptions
      @memoize_when_activated
      def _read_smaps_file(self):
          with open_binary("%s/%s/smaps" % (self._procfs_path, self.pid),
                           buffering=BIGFILE_BUFFERING) as f:
              return f.read().strip()
  
      def oneshot_enter(self):
          self._parse_stat_file.cache_activate(self)
          self._read_status_file.cache_activate(self)
          self._read_smaps_file.cache_activate(self)
  
      def oneshot_exit(self):
          self._parse_stat_file.cache_deactivate(self)
          self._read_status_file.cache_deactivate(self)
          self._read_smaps_file.cache_deactivate(self)
  
      @wrap_exceptions
      def name(self):
          name = self._parse_stat_file()['name']
          if PY3:
              name = decode(name)
          # XXX - gets changed later and probably needs refactoring
          return name
  
      def exe(self):
          try:
              return readlink("%s/%s/exe" % (self._procfs_path, self.pid))
          except (FileNotFoundError, ProcessLookupError):
              # no such file error; might be raised also if the
              # path actually exists for system processes with
              # low pids (about 0-20)
              if os.path.lexists("%s/%s" % (self._procfs_path, self.pid)):
                  return ""
              else:
                  if not pid_exists(self.pid):
                      raise NoSuchProcess(self.pid, self._name)
                  else:
                      raise ZombieProcess(self.pid, self._name, self._ppid)
          except PermissionError:
              raise AccessDenied(self.pid, self._name)
  
      @wrap_exceptions
      def cmdline(self):
          with open_text("%s/%s/cmdline" % (self._procfs_path, self.pid)) as f:
              data = f.read()
          if not data:
              # may happen in case of zombie process
              return []
          # 'man proc' states that args are separated by null bytes '\0'
          # and last char is supposed to be a null byte. Nevertheless
          # some processes may change their cmdline after being started
          # (via setproctitle() or similar), they are usually not
          # compliant with this rule and use spaces instead. Google
          # Chrome process is an example. See:
          # https://github.com/giampaolo/psutil/issues/1179
          sep = '\x00' if data.endswith('\x00') else ' '
          if data.endswith(sep):
              data = data[:-1]
          return data.split(sep)
  
      @wrap_exceptions
      def environ(self):
          with open_text("%s/%s/environ" % (self._procfs_path, self.pid)) as f:
              data = f.read()
          return parse_environ_block(data)
  
      @wrap_exceptions
      def terminal(self):
          tty_nr = int(self._parse_stat_file()['ttynr'])
          tmap = _psposix.get_terminal_map()
          try:
              return tmap[tty_nr]
          except KeyError:
              return None
  
      # May not be available on old kernels.
      if os.path.exists('/proc/%s/io' % os.getpid()):
          @wrap_exceptions
          def io_counters(self):
              fname = "%s/%s/io" % (self._procfs_path, self.pid)
              fields = {}
              with open_binary(fname) as f:
                  for line in f:
                      # https://github.com/giampaolo/psutil/issues/1004
                      line = line.strip()
                      if line:
                          try:
                              name, value = line.split(b': ')
                          except ValueError:
                              # https://github.com/giampaolo/psutil/issues/1004
                              continue
                          else:
                              fields[name] = int(value)
              if not fields:
                  raise RuntimeError("%s file was empty" % fname)
              try:
                  return pio(
                      fields[b'syscr'],  # read syscalls
                      fields[b'syscw'],  # write syscalls
                      fields[b'read_bytes'],  # read bytes
                      fields[b'write_bytes'],  # write bytes
                      fields[b'rchar'],  # read chars
                      fields[b'wchar'],  # write chars
                  )
              except KeyError as err:
                  raise ValueError("%r field was not found in %s; found fields "
                                   "are %r" % (err[0], fname, fields))
  
      @wrap_exceptions
      def cpu_times(self):
          values = self._parse_stat_file()
          utime = float(values['utime']) / CLOCK_TICKS
          stime = float(values['stime']) / CLOCK_TICKS
          children_utime = float(values['children_utime']) / CLOCK_TICKS
          children_stime = float(values['children_stime']) / CLOCK_TICKS
          iowait = float(values['blkio_ticks']) / CLOCK_TICKS
          return pcputimes(utime, stime, children_utime, children_stime, iowait)
  
      @wrap_exceptions
      def cpu_num(self):
          """What CPU the process is on."""
          return int(self._parse_stat_file()['cpu_num'])
  
      @wrap_exceptions
      def wait(self, timeout=None):
          return _psposix.wait_pid(self.pid, timeout, self._name)
  
      @wrap_exceptions
      def create_time(self):
          ctime = float(self._parse_stat_file()['create_time'])
          # According to documentation, starttime is in field 21 and the
          # unit is jiffies (clock ticks).
          # We first divide it for clock ticks and then add uptime returning
          # seconds since the epoch, in UTC.
          # Also use cached value if available.
          bt = BOOT_TIME or boot_time()
          return (ctime / CLOCK_TICKS) + bt
  
      @wrap_exceptions
      def memory_info(self):
          #  ============================================================
          # | FIELD  | DESCRIPTION                         | AKA  | TOP  |
          #  ============================================================
          # | rss    | resident set size                   |      | RES  |
          # | vms    | total program size                  | size | VIRT |
          # | shared | shared pages (from shared mappings) |      | SHR  |
          # | text   | text ('code')                       | trs  | CODE |
          # | lib    | library (unused in Linux 2.6)       | lrs  |      |
          # | data   | data + stack                        | drs  | DATA |
          # | dirty  | dirty pages (unused in Linux 2.6)   | dt   |      |
          #  ============================================================
          with open_binary("%s/%s/statm" % (self._procfs_path, self.pid)) as f:
              vms, rss, shared, text, lib, data, dirty = \
                  [int(x) * PAGESIZE for x in f.readline().split()[:7]]
          return pmem(rss, vms, shared, text, lib, data, dirty)
  
      # /proc/pid/smaps does not exist on kernels < 2.6.14 or if
      # CONFIG_MMU kernel configuration option is not enabled.
      if HAS_SMAPS:
  
          @wrap_exceptions
          def memory_full_info(
                  self,
                  # Gets Private_Clean, Private_Dirty, Private_Hugetlb.
                  _private_re=re.compile(br"\nPrivate.*:\s+(\d+)"),
                  _pss_re=re.compile(br"\nPss\:\s+(\d+)"),
                  _swap_re=re.compile(br"\nSwap\:\s+(\d+)")):
              basic_mem = self.memory_info()
              # Note: using 3 regexes is faster than reading the file
              # line by line.
              # XXX: on Python 3 the 2 regexes are 30% slower than on
              # Python 2 though. Figure out why.
              #
              # You might be tempted to calculate USS by subtracting
              # the "shared" value from the "resident" value in
              # /proc/<pid>/statm. But at least on Linux, statm's "shared"
              # value actually counts pages backed by files, which has
              # little to do with whether the pages are actually shared.
              # /proc/self/smaps on the other hand appears to give us the
              # correct information.
              smaps_data = self._read_smaps_file()
              # Note: smaps file can be empty for certain processes.
              # The code below will not crash though and will result to 0.
              uss = sum(map(int, _private_re.findall(smaps_data))) * 1024
              pss = sum(map(int, _pss_re.findall(smaps_data))) * 1024
              swap = sum(map(int, _swap_re.findall(smaps_data))) * 1024
              return pfullmem(*basic_mem + (uss, pss, swap))
  
      else:
          memory_full_info = memory_info
  
      if HAS_SMAPS:
  
          @wrap_exceptions
          def memory_maps(self):
              """Return process's mapped memory regions as a list of named
              tuples. Fields are explained in 'man proc'; here is an updated
              (Apr 2012) version: http://goo.gl/fmebo
  
              /proc/{PID}/smaps does not exist on kernels < 2.6.14 or if
              CONFIG_MMU kernel configuration option is not enabled.
              """
              def get_blocks(lines, current_block):
                  data = {}
                  for line in lines:
                      fields = line.split(None, 5)
                      if not fields[0].endswith(b':'):
                          # new block section
                          yield (current_block.pop(), data)
                          current_block.append(line)
                      else:
                          try:
                              data[fields[0]] = int(fields[1]) * 1024
                          except ValueError:
                              if fields[0].startswith(b'VmFlags:'):
                                  # see issue #369
                                  continue
                              else:
                                  raise ValueError("don't know how to inte"
                                                   "rpret line %r" % line)
                  yield (current_block.pop(), data)
  
              data = self._read_smaps_file()
              # Note: smaps file can be empty for certain processes.
              if not data:
                  return []
              lines = data.split(b'\n')
              ls = []
              first_line = lines.pop(0)
              current_block = [first_line]
              for header, data in get_blocks(lines, current_block):
                  hfields = header.split(None, 5)
                  try:
                      addr, perms, offset, dev, inode, path = hfields
                  except ValueError:
                      addr, perms, offset, dev, inode, path = \
                          hfields + ['']
                  if not path:
                      path = '[anon]'
                  else:
                      if PY3:
                          path = decode(path)
                      path = path.strip()
                      if (path.endswith(' (deleted)') and not
                              path_exists_strict(path)):
                          path = path[:-10]
                  ls.append((
                      decode(addr), decode(perms), path,
                      data[b'Rss:'],
                      data.get(b'Size:', 0),
                      data.get(b'Pss:', 0),
                      data.get(b'Shared_Clean:', 0),
                      data.get(b'Shared_Dirty:', 0),
                      data.get(b'Private_Clean:', 0),
                      data.get(b'Private_Dirty:', 0),
                      data.get(b'Referenced:', 0),
                      data.get(b'Anonymous:', 0),
                      data.get(b'Swap:', 0)
                  ))
              return ls
  
      @wrap_exceptions
      def cwd(self):
          try:
              return readlink("%s/%s/cwd" % (self._procfs_path, self.pid))
          except (FileNotFoundError, ProcessLookupError):
              # https://github.com/giampaolo/psutil/issues/986
              if not pid_exists(self.pid):
                  raise NoSuchProcess(self.pid, self._name)
              else:
                  raise ZombieProcess(self.pid, self._name, self._ppid)
  
      @wrap_exceptions
      def num_ctx_switches(self,
                           _ctxsw_re=re.compile(br'ctxt_switches:\t(\d+)')):
          data = self._read_status_file()
          ctxsw = _ctxsw_re.findall(data)
          if not ctxsw:
              raise NotImplementedError(
                  "'voluntary_ctxt_switches' and 'nonvoluntary_ctxt_switches'"
                  "lines were not found in %s/%s/status; the kernel is "
                  "probably older than 2.6.23" % (
                      self._procfs_path, self.pid))
          else:
              return _common.pctxsw(int(ctxsw[0]), int(ctxsw[1]))
  
      @wrap_exceptions
      def num_threads(self, _num_threads_re=re.compile(br'Threads:\t(\d+)')):
          # Note: on Python 3 using a re is faster than iterating over file
          # line by line. On Python 2 is the exact opposite, and iterating
          # over a file on Python 3 is slower than on Python 2.
          data = self._read_status_file()
          return int(_num_threads_re.findall(data)[0])
  
      @wrap_exceptions
      def threads(self):
          thread_ids = os.listdir("%s/%s/task" % (self._procfs_path, self.pid))
          thread_ids.sort()
          retlist = []
          hit_enoent = False
          for thread_id in thread_ids:
              fname = "%s/%s/task/%s/stat" % (
                  self._procfs_path, self.pid, thread_id)
              try:
                  with open_binary(fname) as f:
                      st = f.read().strip()
              except FileNotFoundError:
                  # no such file or directory; it means thread
                  # disappeared on us
                  hit_enoent = True
                  continue
              # ignore the first two values ("pid (exe)")
              st = st[st.find(b')') + 2:]
              values = st.split(b' ')
              utime = float(values[11]) / CLOCK_TICKS
              stime = float(values[12]) / CLOCK_TICKS
              ntuple = _common.pthread(int(thread_id), utime, stime)
              retlist.append(ntuple)
          if hit_enoent:
              self._assert_alive()
          return retlist
  
      @wrap_exceptions
      def nice_get(self):
          # with open_text('%s/%s/stat' % (self._procfs_path, self.pid)) as f:
          #   data = f.read()
          #   return int(data.split()[18])
  
          # Use C implementation
          return cext_posix.getpriority(self.pid)
  
      @wrap_exceptions
      def nice_set(self, value):
          return cext_posix.setpriority(self.pid, value)
  
      # starting from CentOS 6.
      if HAS_CPU_AFFINITY:
  
          @wrap_exceptions
          def cpu_affinity_get(self):
              return cext.proc_cpu_affinity_get(self.pid)
  
          def _get_eligible_cpus(
                  self, _re=re.compile(br"Cpus_allowed_list:\t(\d+)-(\d+)")):
              # See: https://github.com/giampaolo/psutil/issues/956
              data = self._read_status_file()
              match = _re.findall(data)
              if match:
                  return list(range(int(match[0][0]), int(match[0][1]) + 1))
              else:
                  return list(range(len(per_cpu_times())))
  
          @wrap_exceptions
          def cpu_affinity_set(self, cpus):
              try:
                  cext.proc_cpu_affinity_set(self.pid, cpus)
              except (OSError, ValueError) as err:
                  if isinstance(err, ValueError) or err.errno == errno.EINVAL:
                      eligible_cpus = self._get_eligible_cpus()
                      all_cpus = tuple(range(len(per_cpu_times())))
                      for cpu in cpus:
                          if cpu not in all_cpus:
                              raise ValueError(
                                  "invalid CPU number %r; choose between %s" % (
                                      cpu, eligible_cpus))
                          if cpu not in eligible_cpus:
                              raise ValueError(
                                  "CPU number %r is not eligible; choose "
                                  "between %s" % (cpu, eligible_cpus))
                  raise
  
      # only starting from kernel 2.6.13
      if HAS_PROC_IO_PRIORITY:
  
          @wrap_exceptions
          def ionice_get(self):
              ioclass, value = cext.proc_ioprio_get(self.pid)
              if enum is not None:
                  ioclass = IOPriority(ioclass)
              return _common.pionice(ioclass, value)
  
          @wrap_exceptions
          def ionice_set(self, ioclass, value):
              if value is None:
                  value = 0
              if value and ioclass in (IOPRIO_CLASS_IDLE, IOPRIO_CLASS_NONE):
                  raise ValueError("%r ioclass accepts no value" % ioclass)
              if value < 0 or value > 7:
                  raise ValueError("value not in 0-7 range")
              return cext.proc_ioprio_set(self.pid, ioclass, value)
  
      if HAS_PRLIMIT:
  
          @wrap_exceptions
          def rlimit(self, resource, limits=None):
              # If pid is 0 prlimit() applies to the calling process and
              # we don't want that. We should never get here though as
              # PID 0 is not supported on Linux.
              if self.pid == 0:
                  raise ValueError("can't use prlimit() against PID 0 process")
              try:
                  if limits is None:
                      # get
                      return cext.linux_prlimit(self.pid, resource)
                  else:
                      # set
                      if len(limits) != 2:
                          raise ValueError(
                              "second argument must be a (soft, hard) tuple, "
                              "got %s" % repr(limits))
                      soft, hard = limits
                      cext.linux_prlimit(self.pid, resource, soft, hard)
              except OSError as err:
                  if err.errno == errno.ENOSYS and pid_exists(self.pid):
                      # I saw this happening on Travis:
                      # https://travis-ci.org/giampaolo/psutil/jobs/51368273
                      raise ZombieProcess(self.pid, self._name, self._ppid)
                  else:
                      raise
  
      @wrap_exceptions
      def status(self):
          letter = self._parse_stat_file()['status']
          if PY3:
              letter = letter.decode()
          # XXX is '?' legit? (we're not supposed to return it anyway)
          return PROC_STATUSES.get(letter, '?')
  
      @wrap_exceptions
      def open_files(self):
          retlist = []
          files = os.listdir("%s/%s/fd" % (self._procfs_path, self.pid))
          hit_enoent = False
          for fd in files:
              file = "%s/%s/fd/%s" % (self._procfs_path, self.pid, fd)
              try:
                  path = readlink(file)
              except (FileNotFoundError, ProcessLookupError):
                  # ENOENT == file which is gone in the meantime
                  hit_enoent = True
                  continue
              except OSError as err:
                  if err.errno == errno.EINVAL:
                      # not a link
                      continue
                  raise
              else:
                  # If path is not an absolute there's no way to tell
                  # whether it's a regular file or not, so we skip it.
                  # A regular file is always supposed to be have an
                  # absolute path though.
                  if path.startswith('/') and isfile_strict(path):
                      # Get file position and flags.
                      file = "%s/%s/fdinfo/%s" % (
                          self._procfs_path, self.pid, fd)
                      try:
                          with open_binary(file) as f:
                              pos = int(f.readline().split()[1])
                              flags = int(f.readline().split()[1], 8)
                      except FileNotFoundError:
                          # fd gone in the meantime; process may
                          # still be alive
                          hit_enoent = True
                      else:
                          mode = file_flags_to_mode(flags)
                          ntuple = popenfile(
                              path, int(fd), int(pos), mode, flags)
                          retlist.append(ntuple)
          if hit_enoent:
              self._assert_alive()
          return retlist
  
      @wrap_exceptions
      def connections(self, kind='inet'):
          ret = _connections.retrieve(kind, self.pid)
          self._assert_alive()
          return ret
  
      @wrap_exceptions
      def num_fds(self):
          return len(os.listdir("%s/%s/fd" % (self._procfs_path, self.pid)))
  
      @wrap_exceptions
      def ppid(self):
          return int(self._parse_stat_file()['ppid'])
  
      @wrap_exceptions
      def uids(self, _uids_re=re.compile(br'Uid:\t(\d+)\t(\d+)\t(\d+)')):
          data = self._read_status_file()
          real, effective, saved = _uids_re.findall(data)[0]
          return _common.puids(int(real), int(effective), int(saved))
  
      @wrap_exceptions
      def gids(self, _gids_re=re.compile(br'Gid:\t(\d+)\t(\d+)\t(\d+)')):
          data = self._read_status_file()
          real, effective, saved = _gids_re.findall(data)[0]
          return _common.pgids(int(real), int(effective), int(saved))
  