#! /usr/bin/python3
# -*- python -*-
# -*- coding: utf-8 -*-
#
# Copyright (C) 2007-2015 Red Hat, Inc.
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; version 2 of the License.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
#

import os, time
from functools import reduce
from six.moves import range
from .utilist import bitmasklist
import platform
import re

VERSION = "0.5"

def is_s390():
    machine = platform.machine()
    if re.search('s390', machine):
        return True
    else:
        return False

def process_cmdline(pid_info):
    """
    Returns the process command line, if available in the given `process' class, if
    not available, falls back to using the comm (short process name) in its pidstat key.
    """
    if pid_info["cmdline"]:
        return reduce(lambda a, b: a + " %s" % b, pid_info["cmdline"]).strip()

    return pid_info["stat"]["comm"]

class pidstat:
    """Provides a dictionary to access the fields in the per process /proc/PID/stat
       files.

       One can obtain the available fields asking for the keys of the dictionary, e.g.:

        >>> p = procfs.pidstat(1)
        >>> print p.keys()
        ['majflt', 'rss', 'cnswap', 'cstime', 'pid', 'session', 'startstack', 'startcode', 'cmajflt', 'blocked', 'exit_signal', 'minflt', 'nswap', 'environ', 'priority', 'state', 'delayacct_blkio_ticks', 'policy', 'rt_priority', 'ppid', 'nice', 'cutime', 'endcode', 'wchan', 'num_threads', 'sigcatch', 'comm', 'stime', 'sigignore', 'tty_nr', 'kstkeip', 'utime', 'tpgid', 'itrealvalue', 'kstkesp', 'rlim', 'signal', 'pgrp', 'flags', 'starttime', 'cminflt', 'vsize', 'processor']

       And then access the various process properties using it as a dictionary:

        >>> print p['comm']
        systemd
        >>> print p['priority']
        20
        >>> print p['state']
        S

       Please refer to the 'procfs(5)' man page, by using:

        $ man 5 procfs

       To see information for each of the above fields, it is part of the
           'man-pages' RPM package.
    """

    # Entries with the same value, the one with a comment after it is the
    # more recent, having replaced the other name in v4.1-rc kernel times.

    PF_ALIGNWARN     = 0x00000001
    PF_STARTING     = 0x00000002
    PF_EXITING     = 0x00000004
    PF_EXITPIDONE     = 0x00000008
    PF_VCPU         = 0x00000010
    PF_WQ_WORKER     = 0x00000020 # /* I'm a workqueue worker */
    PF_FORKNOEXEC     = 0x00000040
    PF_MCE_PROCESS     = 0x00000080 # /* process policy on mce errors */
    PF_SUPERPRIV     = 0x00000100
    PF_DUMPCORE     = 0x00000200
    PF_SIGNALED     = 0x00000400
    PF_MEMALLOC     = 0x00000800
    PF_NPROC_EXCEEDED= 0x00001000 # /* set_user noticed that RLIMIT_NPROC was exceeded */
    PF_FLUSHER     = 0x00001000
    PF_USED_MATH     = 0x00002000
    PF_USED_ASYNC     = 0x00004000 # /* used async_schedule*(), used by module init */
    PF_NOFREEZE     = 0x00008000
    PF_FROZEN     = 0x00010000
    PF_FSTRANS     = 0x00020000
    PF_KSWAPD     = 0x00040000
    PF_MEMALLOC_NOIO = 0x00080000 # /* Allocating memory without IO involved */
    PF_SWAPOFF     = 0x00080000
    PF_LESS_THROTTLE = 0x00100000
    PF_KTHREAD     = 0x00200000
    PF_RANDOMIZE     = 0x00400000
    PF_SWAPWRITE     = 0x00800000
    PF_SPREAD_PAGE     = 0x01000000
    PF_SPREAD_SLAB     = 0x02000000
    PF_THREAD_BOUND     = 0x04000000
    PF_NO_SETAFFINITY = 0x04000000 # /* Userland is not allowed to meddle with cpus_allowed */
    PF_MCE_EARLY     = 0x08000000 # /* Early kill for mce process policy */
    PF_MEMPOLICY     = 0x10000000
    PF_MUTEX_TESTER     = 0x20000000
    PF_FREEZER_SKIP     = 0x40000000
    PF_FREEZER_NOSIG = 0x80000000
    PF_SUSPEND_TASK     = 0x80000000 # /* this thread called freeze_processes and should not be frozen */

    proc_stat_fields = ["pid", "comm", "state", "ppid", "pgrp", "session",
                 "tty_nr", "tpgid", "flags", "minflt", "cminflt",
                 "majflt", "cmajflt", "utime", "stime", "cutime",
                 "cstime", "priority", "nice", "num_threads",
                 "itrealvalue", "starttime", "vsize", "rss",
                 "rlim", "startcode", "endcode", "startstack",
                 "kstkesp", "kstkeip", "signal", "blocked",
                 "sigignore", "sigcatch", "wchan", "nswap",
                 "cnswap", "exit_signal", "processor",
                 "rt_priority", "policy",
                 "delayacct_blkio_ticks", "environ"]

    def __init__(self, pid, basedir="/proc"):
        self.pid = pid
        self.load(basedir)

    def __getitem__(self, fieldname):
        return self.fields[fieldname]

    def keys(self):
        return list(self.fields.keys())

    def values(self):
        return list(self.fields.values())

    def has_key(self, fieldname):
        return fieldname in self.fields

    def items(self):
        return self.fields

    def __contains__(self, fieldname):
        return fieldname in self.fields

    def load(self, basedir="/proc"):
        f = open("%s/%d/stat" % (basedir, self.pid))
        fields = f.readline().strip().split(') ')
        f.close()
        fields = fields[0].split(' (') + fields[1].split()
        self.fields = {}
        nr_fields = min(len(fields), len(self.proc_stat_fields))
        for i in range(nr_fields):
            attrname = self.proc_stat_fields[i]
            value = fields[i]
            if attrname == "comm":
                self.fields["comm"] = value.strip('()')
            else:
                try:
                    self.fields[attrname] = int(value)
                except:
                    self.fields[attrname] = value

    def is_bound_to_cpu(self):
        """
        Returns true if this process has a fixed smp affinity mask,
                not allowing it to be moved to a different set of CPUs.
        """
        return self.fields["flags"] & self.PF_THREAD_BOUND and \
            True or False

    def process_flags(self):
        """
        Returns a list with all the process flags known, details depend
        on kernel version, declared in the file include/linux/sched.h in
        the kernel sources.

        As of v4.2-rc7 these include (from include/linux/sched.h comments):

            PF_EXITING       Getting shut down
            PF_EXITPIDONE       Pi exit done on shut down
            PF_VCPU           I'm a virtual CPU
            PF_WQ_WORKER       I'm a workqueue worker
            PF_FORKNOEXEC       Forked but didn't exec
            PF_MCE_PROCESS       Process policy on mce errors
            PF_SUPERPRIV       Used super-user privileges
            PF_DUMPCORE       Dumped core
            PF_SIGNALED       Killed by a signal
            PF_MEMALLOC       Allocating memory
            PF_NPROC_EXCEEDED  Set_user noticed that RLIMIT_NPROC was exceeded
            PF_USED_MATH       If unset the fpu must be initialized before use
            PF_USED_ASYNC       Used async_schedule*(), used by module init
            PF_NOFREEZE       This thread should not be frozen
            PF_FROZEN       Frozen for system suspend
            PF_FSTRANS       Inside a filesystem transaction
            PF_KSWAPD       I am kswapd
            PF_MEMALLOC_NOIO   Allocating memory without IO involved
            PF_LESS_THROTTLE   Throttle me less: I clean memory
            PF_KTHREAD       I am a kernel thread
            PF_RANDOMIZE       Randomize virtual address space
            PF_SWAPWRITE       Allowed to write to swap
            PF_NO_SETAFFINITY  Userland is not allowed to meddle with cpus_allowed
            PF_MCE_EARLY       Early kill for mce process policy
            PF_MUTEX_TESTER       Thread belongs to the rt mutex tester
            PF_FREEZER_SKIP       Freezer should not count it as freezable
            PF_SUSPEND_TASK       This thread called freeze_processes and should not be frozen

        """
        sflags = []
        for attr in dir(self):
            if attr[:3] != "PF_":
                continue
            value = getattr(self, attr)
            if value & self.fields["flags"]:
                sflags.append(attr)

        return sflags

def cannot_set_affinity(self, pid):
    PF_NO_SETAFFINITY = 0x04000000
    try:
        return int(self.processes[pid]["stat"]["flags"]) & \
          PF_NO_SETAFFINITY and True or False
    except:
        return True

def cannot_set_thread_affinity(self, pid, tid):
    PF_NO_SETAFFINITY = 0x04000000
    try:
        return int(self.processes[pid].threads[tid]["stat"]["flags"]) & \
          PF_NO_SETAFFINITY and True or False
    except:
        return True

class pidstatus:
    """
    Provides a dictionary to access the fields in the per process /proc/PID/status
    files. This provides additional information about processes and threads to what
    can be obtained with the procfs.pidstat() class.

    One can obtain the available fields asking for the keys of the dictionary, e.g.:

        >>> import procfs
        >>> p = procfs.pidstatus(1)
        >>> print p.keys()
        ['VmExe', 'CapBnd', 'NSpgid', 'Tgid', 'NSpid', 'VmSize', 'VmPMD', 'ShdPnd', 'State', 'Gid', 'nonvoluntary_ctxt_switches', 'SigIgn', 'VmStk', 'VmData', 'SigCgt', 'CapEff', 'VmPTE', 'Groups', 'NStgid', 'Threads', 'PPid', 'VmHWM', 'NSsid', 'VmSwap', 'Name', 'SigBlk', 'Mems_allowed_list', 'VmPeak', 'Ngid', 'VmLck', 'SigQ', 'VmPin', 'Mems_allowed', 'CapPrm', 'Seccomp', 'VmLib', 'Cpus_allowed', 'Uid', 'SigPnd', 'Pid', 'Cpus_allowed_list', 'TracerPid', 'CapInh', 'voluntary_ctxt_switches', 'VmRSS', 'FDSize']
        >>> print p["Pid"]
        1
        >>> print p["Threads"]
        1
        >>> print p["VmExe"]
        1248 kB
        >>> print p["Cpus_allowed"]
        f
        >>> print p["SigQ"]
        0/30698
        >>> print p["VmPeak"]
        320300 kB
        >>>

    Please refer to the 'procfs(5)' man page, by using:

        $ man 5 procfs

    To see information for each of the above fields, it is part of the
    'man-pages' RPM package.

    In the man page there will be references to further documentation, like
        referring to the "getrlimit(2)" man page when explaining the "SigQ"
        line/field.
    """

    def __init__(self, pid, basedir="/proc"):
        self.pid = pid
        self.load(basedir)

    def __getitem__(self, fieldname):
        return self.fields[fieldname]

    def keys(self):
        return list(self.fields.keys())

    def values(self):
        return list(self.fields.values())

    def has_key(self, fieldname):
        return fieldname in self.fields

    def items(self):
        return self.fields

    def __contains__(self, fieldname):
        return fieldname in self.fields

    def load(self, basedir="/proc"):
        f = open("%s/%d/status" % (basedir, self.pid))
        self.fields = {}
        for line in f.readlines():
            fields = line.split(":")
            if len(fields) != 2:
                continue
            name = fields[0]
            value = fields[1].strip()
            try:
                self.fields[name] = int(value)
            except:
                self.fields[name] = value
        f.close()

class process:
    """
    Information about a process with a given pid, provides a dictionary with
    two entries, instances of different wrappers for /proc/ process related
    meta files: "stat" and "status", see the documentation for procfs.pidstat
    and procfs.pidstatus for further info about those classes.
    """

    def __init__(self, pid, basedir="/proc"):
        self.pid = pid
        self.basedir = basedir

    def __getitem__(self, attr):
        if not hasattr(self, attr):
            if attr in ("stat", "status"):
                if attr == "stat":
                    sclass = pidstat
                else:
                    sclass = pidstatus

                setattr(self, attr, sclass(self.pid, self.basedir))
            elif attr == "cmdline":
                self.load_cmdline()
            elif attr == "threads":
                self.load_threads()
            elif attr == "cgroups":
                self.load_cgroups()
            elif attr == "environ":
                self.load_environ()

        return getattr(self, attr)

    def has_key(self, attr):
        return hasattr(self, attr)

    def __contains__(self, attr):
        return hasattr(self, attr)

    def load_cmdline(self):
        f = open("/proc/%d/cmdline" % self.pid)
        self.cmdline = f.readline().strip().split('\0')[:-1]
        f.close()

    def load_threads(self):
        self.threads = pidstats("/proc/%d/task/" % self.pid)
        # remove thread leader
        del self.threads[self.pid]

    def load_cgroups(self):
        f = open("/proc/%d/cgroup" % self.pid)
        self.cgroups = ""
        for line in reversed(f.readlines()):
            if len(self.cgroups):
                self.cgroups = self.cgroups + "," + line[:-1]
            else:
                self.cgroups = line[:-1]
        f.close()

    def load_environ(self):
        """
        Loads the environment variables for this process. The entries then
        become available via the 'environ' member, or via the 'environ'
        dict key when accessing as p["environ"].

        E.g.:


        >>> all_processes = procfs.pidstats()
        >>> firefox_pid = all_processes.find_by_name("firefox")
        >>> firefox_process = all_processes[firefox_pid[0]]
        >>> print firefox_process["environ"]["PWD"]
        /home/acme
        >>> print len(firefox_process.environ.keys())
        66
        >>> print firefox_process["environ"]["SHELL"]
        /bin/bash
        >>> print firefox_process["environ"]["USERNAME"]
        acme
        >>> print firefox_process["environ"]["HOME"]
        /home/acme
        >>> print firefox_process["environ"]["MAIL"]
        /var/spool/mail/acme
        >>>
        """
        self.environ = {}
        f = open("/proc/%d/environ" % self.pid)
        for x in f.readline().split('\0'):
            if len(x) > 0:
                y = x.split('=')
                self.environ[y[0]] = y[1]
        f.close()

class pidstats:
    """
    Provides access to all the processes in the system, to get a picture of
    how many processes there are at any given moment.

    The entries can be accessed as a dictionary, keyed by pid. Also there are
    methods to find processes that match a given COMM or regular expression.
    """
    def __init__(self, basedir="/proc"):
        self.basedir = basedir
        self.processes = {}
        self.reload()

    def __getitem__(self, key):
        return self.processes[key]

    def __delitem__(self, key):
        # not clear on why this can fail, but it can
        try:
            del self.processes[key]
        except:
            pass

    def keys(self):
        return list(self.processes.keys())

    def values(self):
        return list(self.processes.values())

    def has_key(self, key):
        return key in self.processes

    def items(self):
        return self.processes

    def __contains__(self, key):
        return key in self.processes

    def reload(self):
        """
        This operation will throw away the current dictionary contents, if any, and
        read all the pid files from /proc/, instantiating a 'process' instance for
        each of them.

        This is a high overhead operation, and should be avoided if the perf python
        binding can be used to detect when new threads appear and existing ones
        terminate.

        In RHEL it is found in the python-perf rpm package.

        More information about the perf facilities can be found in the 'perf_event_open'
        man page.
        """
        del self.processes
        self.processes = {}
        pids = os.listdir(self.basedir)
        for spid in pids:
            try:
                pid = int(spid)
            except:
                continue

            self.processes[pid] = process(pid, self.basedir)

    def reload_threads(self):
        to_remove = []
        for pid in list(self.processes.keys()):
            try:
                self.processes[pid].load_threads()
            except OSError:
                # process vanished, remove it
                to_remove.append(pid)
        for pid in to_remove:
            del self.processes[pid]

    def find_by_name(self, name):
        name = name[:15]
        pids = []
        for pid in list(self.processes.keys()):
            try:
                if name == self.processes[pid]["stat"]["comm"]:
                    pids.append(pid)
            except IOError:
                # We're doing lazy loading of /proc files
                # So if we get this exception is because the
                # process vanished, remove it
                del self.processes[pid]

        return pids

    def find_by_regex(self, regex):
        pids = []
        for pid in list(self.processes.keys()):
            try:
                if regex.match(self.processes[pid]["stat"]["comm"]):
                    pids.append(pid)
            except IOError:
                # We're doing lazy loading of /proc files
                # So if we get this exception is because the
                # process vanished, remove it
                del self.processes[pid]
        return pids

    def find_by_cmdline_regex(self, regex):
        pids = []
        for pid in list(self.processes.keys()):
            try:
                if regex.match(process_cmdline(self.processes[pid])):
                    pids.append(pid)
            except IOError:
                # We're doing lazy loading of /proc files
                # So if we get this exception is because the
                # process vanished, remove it
                del self.processes[pid]
        return pids

    def get_per_cpu_rtprios(self, basename):
        cpu = 0
        priorities = ""
        processed_pids = []
        while True:
            name = "%s/%d" % (basename, cpu)
            pids = self.find_by_name(name)
            if not pids or len([n for n in pids if n not in processed_pids]) == 0:
                break
            for pid in pids:
                try:
                    priorities += "%s," % self.processes[pid]["stat"]["rt_priority"]
                except IOError:
                    # We're doing lazy loading of /proc files
                    # So if we get this exception is because the
                    # process vanished, remove it
                    del self.processes[pid]
            processed_pids += pids
            cpu += 1

        priorities = priorities.strip(',')
        return priorities

    def get_rtprios(self, name):
        cpu = 0
        priorities = ""
        processed_pids = []
        while True:
            pids = self.find_by_name(name)
            if not pids or len([n for n in pids if n not in processed_pids]) == 0:
                break
            for pid in pids:
                try:
                    priorities += "%s," % self.processes[pid]["stat"]["rt_priority"]
                except IOError:
                    # We're doing lazy loading of /proc files
                    # So if we get this exception is because the
                    # process vanished, remove it
                    del self.processes[pid]
            processed_pids += pids
            cpu += 1

        priorities = priorities.strip(',')
        return priorities

    def is_bound_to_cpu(self, pid):
        """
        Checks if a given pid can't have its SMP affinity mask changed.
        """
        return self.processes[pid]["stat"].is_bound_to_cpu()

class interrupts:
    """
    Information about IRQs in the system. A dictionary keyed by IRQ number
    will have as its value another dictionary with "cpu", "type" and "users"
    keys, with the SMP affinity mask, type of IRQ and the drivers associated
    with each interrupt.

    The information comes from the /proc/interrupts file, documented in
    'man procfs(5)', for instance, the 'cpu' dict is an array with one entry
    per CPU present in the sistem, each value being the number of interrupts
    that took place per CPU.

    E.g.:

    >>> import procfs
    >>> interrupts = procfs.interrupts()
    >>> thunderbolt_irq = interrupts.find_by_user("thunderbolt")
    >>> print thunderbolt_irq
    34
    >>> thunderbolt = interrupts[thunderbolt_irq]
    >>> print thunderbolt
    {'affinity': [0, 1, 2, 3], 'type': 'PCI-MSI', 'cpu': [3495, 0, 81, 0], 'users': ['thunderbolt']}
    >>>
    """
    def __init__(self):
        self.interrupts = {}
        self.reload()

    def __getitem__(self, key):
        return self.interrupts[str(key)]

    def keys(self):
        return list(self.interrupts.keys())

    def values(self):
        return list(self.interrupts.values())

    def has_key(self, key):
        return str(key) in self.interrupts

    def items(self):
        return self.interrupts

    def __contains__(self, key):
        return str(key) in self.interrupts

    def reload(self):
        del self.interrupts
        self.interrupts = {}
        f = open("/proc/interrupts")

        for line in f.readlines():
            line = line.strip()
            fields = line.split()
            if fields[0][:3] == "CPU":
                self.nr_cpus = len(fields)
                continue
            irq = fields[0].strip(":")
            self.interrupts[irq] = {}
            self.interrupts[irq] = self.parse_entry(fields[1:], line)
            try:
                nirq = int(irq)
            except:
                continue
            self.interrupts[irq]["affinity"] = self.parse_affinity(nirq)

        f.close()

    def parse_entry(self, fields, line):
        dict = {}
        dict["cpu"] = []
        dict["cpu"].append(int(fields[0]))
        nr_fields = len(fields)
        if nr_fields >= self.nr_cpus:
            dict["cpu"] += [int(i) for i in fields[1:self.nr_cpus]]
            if nr_fields > self.nr_cpus:
                dict["type"] = fields[self.nr_cpus]
                # look if there are users (interrupts 3 and 4 haven't)
                if nr_fields > self.nr_cpus + 1:
                    dict["users"] = [a.strip() for a in fields[nr_fields - 1].split(',')]
                else:
                    dict["users"] = []
        return dict

    def parse_affinity(self, irq):
        try:
            f = open("/proc/irq/%s/smp_affinity" % irq)
            line = f.readline()
            f.close()
            return bitmasklist(line, self.nr_cpus)
        except IOError:
            return [0, ]

    def find_by_user(self, user):
        """
        Looks up a interrupt number by the name of one of its users"

        E.g.:

        >>> import procfs
        >>> interrupts = procfs.interrupts()
        >>> thunderbolt_irq = interrupts.find_by_user("thunderbolt")
        >>> print thunderbolt_irq
        34
        >>> thunderbolt = interrupts[thunderbolt_irq]
        >>> print thunderbolt
        {'affinity': [0, 1, 2, 3], 'type': 'PCI-MSI', 'cpu': [3495, 0, 81, 0], 'users': ['thunderbolt']}
        >>>
        """
        for i in list(self.interrupts.keys()):
            if "users" in self.interrupts[i] and \
               user in self.interrupts[i]["users"]:
                return i
        return None

    def find_by_user_regex(self, regex):
        """
        Looks up a interrupt number by a regex that matches names of its users"

        E.g.:

        >>> import procfs
        >>> import re
        >>> interrupts = procfs.interrupts()
        >>> usb_controllers = interrupts.find_by_user_regex(re.compile(".*hcd"))
        >>> print usb_controllers
        ['22', '23', '31']
        >>> print [ interrupts[irq]["users"] for irq in usb_controllers ]
        [['ehci_hcd:usb4'], ['ehci_hcd:usb3'], ['xhci_hcd']]
        >>>
        """
        irqs = []
        for i in list(self.interrupts.keys()):
            if "users" not in self.interrupts[i]:
                continue
            for user in self.interrupts[i]["users"]:
                if regex.match(user):
                    irqs.append(i)
                    break
        return irqs

class cmdline:
    """
    Parses the kernel command line (/proc/cmdline), turning it into a dictionary."

    Useful to figure out if some kernel boolean knob has been turned on, as well
    as to find the value associated to other kernel knobs.

    It can also be used to find out about parameters passed to the init process,
    such as 'BOOT_IMAGE', etc.

    E.g.:
    >>> import procfs
    >>> kcmd = procfs.cmdline()
    >>> print kcmd.keys()
    ['LANG', 'BOOT_IMAGE', 'quiet', 'rhgb', 'rd.lvm.lv', 'ro', 'root']
    >>> print kcmd["BOOT_IMAGE"]
    /vmlinuz-4.3.0-rc1+
    >>>
    """

    def __init__(self):
        self.options = {}
        self.parse()

    def parse(self):
        f = open("/proc/cmdline")
        for option in f.readline().strip().split():
            fields = option.split("=")
            if len(fields) == 1:
                self.options[fields[0]] = True
            else:
                self.options[fields[0]] = fields[1]

        f.close()

    def __getitem__(self, key):
        return self.options[key]

    def keys(self):
        return list(self.options.keys())

    def values(self):
        return list(self.options.values())

    def items(self):
        return self.options

class cpuinfo:
    """
    Dictionary with information about CPUs in the system.

    Please refer to 'man procfs(5)' for further information about the
        '/proc/cpuinfo' file, that is the source of the information provided by this
        class. The 'man lscpu(1)' also has information about a program that uses
    the '/proc/cpuinfo' file.

    Using this class one can obtain the number of CPUs in a system:

      >>> cpus = procfs.cpuinfo()
          >>> print cpus.nr_cpus
          4

    It is also possible to figure out aspects of the CPU topology, such as
    how many CPU physical sockets exists, i.e. groups of CPUs sharing components
    such as CPU memory caches:

      >>> print len(cpus.sockets)
      1

    Additionally dictionary with information common to all CPUs in the system is
    available:

      >>> print cpus["model name"]
          Intel(R) Core(TM) i7-3667U CPU @ 2.00GHz
          >>> print cpus["cache size"]
          4096 KB
          >>>
    """
    def __init__(self, filename="/proc/cpuinfo"):
        self.tags = {}
        self.nr_cpus = 0
        self.sockets = []
        self.parse(filename)

    def __getitem__(self, key):
        return self.tags[key.lower()]

    def keys(self):
        return list(self.tags.keys())

    def values(self):
        return list(self.tags.values())

    def items(self):
        return self.tags

    def parse(self, filename):
        f = open(filename)
        for line in f.readlines():
            line = line.strip()
            if not line:
                continue
            fields = line.split(":")
            tagname = fields[0].strip().lower()
            if tagname == "processor":
                self.nr_cpus += 1
                continue
            elif is_s390() and tagname == "cpu number":
                self.nr_cpus += 1
                continue
            elif tagname == "core id":
                continue
            self.tags[tagname] = fields[1].strip()
            if tagname == "physical id":
                socket_id = self.tags[tagname]
                if socket_id not in self.sockets:
                    self.sockets.append(socket_id)

        f.close()
        self.nr_sockets = self.sockets and len(self.sockets) or \
                  (self.nr_cpus / ("siblings" in self.tags and int(self.tags["siblings"]) or 1))
        self.nr_cores = ("cpu cores" in self.tags and int(self.tags["cpu cores"]) or 1) * self.nr_sockets

class smaps_lib:
    """
    Representation of an mmap in place for a process. Can be used to figure
    out which processes have an library mapped, etc.

    The 'perm' member can be used to figure out executable mmaps, i.e. libraries.

    The 'vm_start' and 'vm_end' in turn can be used when trying to resolve
    processor instruction pointer addresses to a symbol name in a library.
    """
    def __init__(self, lines):
        fields = lines[0].split()
        self.vm_start, self.vm_end = [int(a, 16) for a in fields[0].split("-")]
        self.perms = fields[1]
        self.offset = int(fields[2], 16)
        self.major, self.minor = fields[3].split(":")
        self.inode = int(fields[4])
        if len(fields) > 5:
            self.name = fields[5]
        else:
            self.name = None
        self.tags = {}
        for line in lines[1:]:
            fields = line.split()
            tag = fields[0][:-1].lower()
            try:
                self.tags[tag] = int(fields[1])
            except:
                # VmFlags are strings
                self.tags[tag] = fields

    def __getitem__(self, key):
        return self.tags[key.lower()]

    def keys(self):
        return list(self.tags.keys())

    def values(self):
        return list(self.tags.values())

    def items(self):
        return self.tags


class smaps:
    """
    List of libraries mapped by a process. Parses the lines in
    the /proc/PID/smaps file, that is further documented in the
    procfs(5) man page.

    Example: Listing the executable maps for the 'sshd' process:

          >>> import procfs
          >>> processes = procfs.pidstats()
          >>> sshd = processes.find_by_name("sshd")
          >>> sshd_maps = procfs.smaps(sshd[0])
          >>> for i in range(len(sshd_maps)):
          ...     if 'x' in sshd_maps[i].perms:
          ...         print "%s: %s" % (sshd_maps[i].name, sshd_maps[i].perms)
          ...
          /usr/sbin/sshd: r-xp
          /usr/lib64/libnss_files-2.20.so: r-xp
          /usr/lib64/librt-2.20.so: r-xp
          /usr/lib64/libkeyutils.so.1.5: r-xp
          /usr/lib64/libkrb5support.so.0.1: r-xp
          /usr/lib64/libfreebl3.so: r-xp
          /usr/lib64/libpthread-2.20.so: r-xp
      ...
    """
    def __init__(self, pid):
        self.pid = pid
        self.entries = []
        self.reload()

    def parse_entry(self, f, line):
        lines = []
        if not line:
            line = f.readline().strip()
        if not line:
            return
        lines.append(line)
        while True:
            line = f.readline()
            if not line:
                break
            line = line.strip()
            if line.split()[0][-1] == ':':
                lines.append(line)
            else:
                break
        self.entries.append(smaps_lib(lines))
        return line

    def __len__(self):
        return len(self.entries)

    def __getitem__(self, index):
        return self.entries[index]

    def reload(self):
        f = open("/proc/%d/smaps" % self.pid)
        line = None
        while True:
            line = self.parse_entry(f, line)
            if not line:
                break
        f.close()
        self.nr_entries = len(self.entries)

    def find_by_name_fragment(self, fragment):
        result = []
        for i in range(self.nr_entries):
            if self.entries[i].name and \
               self.entries[i].name.find(fragment) >= 0:
                   result.append(self.entries[i])

        return result

class cpustat:
    """
    CPU statistics, obtained from a line in the '/proc/stat' file, Please
    refer to 'man procfs(5)' for further information about the '/proc/stat'
    file, that is the source of the information provided by this class.
    """

    def __init__(self, fields):
        self.name = fields[0]
        (self.user,
         self.nice,
         self.system,
         self.idle,
         self.iowait,
         self.irq,
         self.softirq) = [int(i) for i in fields[1:8]]
        if len(fields) > 7:
            self.steal = int(fields[7])
            if len(fields) > 8:
                self.guest = int(fields[8])

    def __repr__(self):
        s = "< user: %s, nice: %s, system: %s, idle: %s, iowait: %s, irq: %s, softirq: %s" % \
            (self.user, self.nice, self.system, self.idle, self.iowait, self.irq, self.softirq)
        if hasattr(self, 'steal'):
            s += ", steal: %d" % self.steal
        if hasattr(self, 'guest'):
            s += ", guest: %d" % self.guest
        return s + ">"

class cpusstats:
    """
    Dictionary with information about CPUs in the system. First entry in the
    dictionary gives an aggregate view of all CPUs, each other entry is about
    separate CPUs. Please refer to 'man procfs(5)' for further information
    about the '/proc/stat' file, that is the source of the information provided
    by this class.
    """
    def __init__(self, filename="/proc/stat"):
        self.entries = {}
        self.time = None
        self.hertz = os.sysconf(2)
        self.filename = filename
        self.reload()

    def __iter__(self):
        return iter(self.entries)

    def __getitem__(self, key):
        return self.entries[key]

    def __len__(self):
        return len(list(self.entries.keys()))

    def keys(self):
        return list(self.entries.keys())

    def values(self):
        return list(self.entries.values())

    def items(self):
        return self.entries

    def reload(self):
        last_entries = self.entries
        self.entries = {}
        f = open(self.filename)
        for line in f.readlines():
            fields = line.strip().split()
            if fields[0][:3].lower() != "cpu":
                continue
            c = cpustat(fields)
            if c.name == "cpu":
                idx = 0
            else:
                idx = int(c.name[3:]) + 1
            self.entries[idx] = c
        f.close()
        last_time = self.time
        self.time = time.time()
        if last_entries:
            delta_sec = self.time - last_time
            interval_hz = delta_sec * self.hertz
            for cpu in list(self.entries.keys()):
                if cpu not in last_entries:
                    curr.usage = 0
                    continue
                curr = self.entries[cpu]
                prev = last_entries[cpu]
                delta = (curr.user - prev.user) + \
                    (curr.nice - prev.nice) + \
                    (curr.system - prev.system)
                curr.usage = (delta / interval_hz) * 100
                if curr.usage > 100:
                    curr.usage = 100

if __name__ == '__main__':
    import sys

    ints = interrupts()

    for i in list(ints.interrupts.keys()):
        print("%s: %s" % (i, ints.interrupts[i]))

    options = cmdline()
    for o in list(options.options.keys()):
        print("%s: %s" % (o, options.options[o]))

    cpu = cpuinfo()
    print("\ncpuinfo data: %d processors" % cpu.nr_cpus)
    for tag in list(cpu.keys()):
        print("%s=%s" % (tag, cpu[tag]))

    print("smaps:\n" + ("-" * 40))
    s = smaps(int(sys.argv[1]))
    for i in range(s.nr_entries):
        print("%#x %s" % (s.entries[i].vm_start, s.entries[i].name))
    print("-" * 40)
    for a in s.find_by_name_fragment(sys.argv[2]):
        print(a["Size"])

    ps = pidstats()
    print(ps[1])

    cs = cpusstats()
    while True:
        time.sleep(1)
        cs.reload()
        for cpu in cs:
            print("%s: %d" % (cpu.name, cpu.usage))
        print("-" * 10)
