# 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 NIC_DUPLEX_FULL
from ._common import NIC_DUPLEX_HALF
from ._common import NIC_DUPLEX_UNKNOWN
from ._common import AccessDenied
from ._common import NoSuchProcess
from ._common import ZombieProcess
from ._common import bcat
from ._common import cat
from ._common import debug
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 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 PY3
from ._compat import FileNotFoundError
from ._compat import PermissionError
from ._compat import ProcessLookupError
from ._compat import b
from ._compat import basestring


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_PROC_SMAPS = os.path.exists('/proc/%s/smaps' % os.getpid())
HAS_PROC_SMAPS_ROLLUP = os.path.exists('/proc/%s/smaps_rollup' % os.getpid())
HAS_PROC_IO_PRIORITY = hasattr(cext, "proc_ioprio_get")
HAS_CPU_AFFINITY = hasattr(cext, "proc_cpu_affinity_get")

# Number of clock ticks per second
CLOCK_TICKS = os.sysconf("SC_CLK_TCK")
PAGESIZE = cext_posix.getpagesize()
BOOT_TIME = None  # set later
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
}


# =====================================================================
# --- 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.
    """
    # Re-adapted 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)


try:
    set_scputimes_ntuple("/proc")
except Exception:  # pragma: no cover
    # Don't want to crash at import time.
    traceback.print_exc()
    scputimes = namedtuple('scputimes', 'user system idle')(0.0, 0.0, 0.0)


# =====================================================================
# --- prlimit
# =====================================================================

# Backport of resource.prlimit() for Python 2. Originally this was done
# in C, but CentOS-6 which we use to create manylinux wheels is too old
# and does not support prlimit() syscall. As such the resulting wheel
# would not include prlimit(), even when installed on newer systems.
# This is the only part of psutil using ctypes.

prlimit = None
try:
    from resource import prlimit  # python >= 3.4
except ImportError:
    import ctypes

    libc = ctypes.CDLL(None, use_errno=True)

    if hasattr(libc, "prlimit"):

        def prlimit(pid, resource_, limits=None):
            class StructRlimit(ctypes.Structure):
                _fields_ = [('rlim_cur', ctypes.c_longlong),
                            ('rlim_max', ctypes.c_longlong)]

            current = StructRlimit()
            if limits is None:
                # get
                ret = libc.prlimit(pid, resource_, None, ctypes.byref(current))
            else:
                # set
                new = StructRlimit()
                new.rlim_cur = limits[0]
                new.rlim_max = limits[1]
                ret = libc.prlimit(
                    pid, resource_, ctypes.byref(new), ctypes.byref(current))

            if ret != 0:
                errno = ctypes.get_errno()
                raise OSError(errno, os.strerror(errno))
            return (current.rlim_cur, current.rlim_max)


if prlimit is not None:
    __extra__all__.extend(
        [x for x in dir(cext) if x.startswith('RLIM') and x.isupper()])


# =====================================================================
# --- system memory
# =====================================================================


def calculate_avail_vmem(mems):