# -*- encoding: utf-8 -*-
# Software Management Providers
#
# Copyright (C) 2012 Red Hat, Inc.  All rights reserved.
#
# This library is free software; you can redistribute it and/or
# modify it under the terms of the GNU Lesser General Public
# License as published by the Free Software Foundation; either
# version 2.1 of the License, or (at your option) any later version.
#
# This library 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
# Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public
# License along with this library; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
#
# Authors: Michal Minar <miminar@redhat.com>
#

"""Common utilities for LMI_Software* providers
"""

import collections
from datetime import datetime
import grp
import hashlib
import itertools
import os
import platform
import pwd
import re
import rpm
import socket
import stat
import pywbem
import yum
import cmpi_pywbem_bindings as pycimmb
from openlmi.software.util import singletonmixin

RE_EVRA  = re.compile(r'^(?P<epoch>\d+):(?P<ver>[^-]+)'
                r'-(?P<rel>.+)\.(?P<arch>[^.]+)$')
RE_NEVRA = re.compile(r'^(?P<name>.+)-(?P<evra>((?P<epoch>\d+):)?(?P<ver>[^-]+)'
                r'-(?P<rel>.+)\.(?P<arch>[^.]+))$')

RPMDB_PATH = '/var/lib/rpm/Packages'

class YumDB(singletonmixin.Singleton):
    """
    Context manager for accessing yum/rpm database.
    """

    # this is to inform Singleton, that __init__ should be called only once
    ignoreSubsequent = True

    def __init__(self, env, *args, **kwargs):   #pylint: disable=W0231
        if not isinstance(env, pycimmb.ProviderEnvironment):
            raise TypeError("env must be instance of"
                    " pycimmb.ProviderEnvironment")
        self._yum_args = (args, kwargs)
        self._yum = None
        self._db_mtime = 0
        self._lock_cnt = 0
        self.env = env
        env.get_logger().log_info('init called')

    def is_dirty(self):
        """
        @return True if rpm database has been modified since last update
        """
        return self._db_mtime < os.stat(RPMDB_PATH).st_mtime

    def is_locked(self):
        """
        @return True if rpm database is locked
        """
        return self._yum._lockfile is not None

    def update_db(self):
        """
        Call to update database metadata.
        """
        self.env.get_logger().log_info('updating rpmdb')
        self._db_mtime = os.stat(RPMDB_PATH).st_mtime
        self._yum.doConfigSetup()
        self._yum.doTsSetup()
        self._yum.doRpmDBSetup()

    def __enter__(self):
        self._lock_cnt += 1
        if self._lock_cnt < 2:
            self._yum = yum.YumBase(*self._yum_args[0], **self._yum_args[1])
            if not self.is_locked() and self.is_dirty():
                self.update_db()
            self._yum.doLock()
        return self

    def __exit__(self, exc_type, exc_value, traceback):
        if self._lock_cnt == 1:
            del self._yum
        self._lock_cnt -= 1

    def __getattr__(self, name):
        if not self.is_locked() and self.is_dirty():
            self.update_db()
        return getattr(self._yum, name)


def _get_distname():
    """
    @return name of linux distribution
    """
    if hasattr(platform, 'linux_distribution'):
        return platform.linux_distribution(
                full_distribution_name=False)[0].lower()
    else:
        return platform.dist()[0].lower()


def get_target_operating_system():
    """
    @return (val, text).
    Where val is a number from ValueMap of TargetOperatingSystem property
    of CIM_SoftwareElement class and text is its testual representation.
    """

    system = platform.system() 
    if system.lower() == 'linux':
        try:
            val, dist = \
            { 'redhat'   : (79, 'RedHat Enterprise Linux')
            , 'suse'     : (81, 'SUSE')
            , 'mandriva' : (88, 'Mandriva')
            , 'ubuntu'   : (93, 'Ubuntu')
            , 'debian'   : (95, 'Debian')
            }[_get_distname()]
        except KeyError:
            linrel = platform.uname()[2]
            if linrel.startswith('2.4'):
                val, dist = (97, 'Linux 2.4.x')
            elif linrel.startswith('2.6'):
                val, dist = (99, 'Linux 2.6.x')
            else:
                return (36, 'LINUX') # no check for x86_64
        if platform.machine() == 'x86_64':
            val  += 1
            dist += ' 64-Bit'
        return (val, dist)
    elif system.lower() in ('macosx', 'darwin'):
        return (2, 'MACOS')
    # elif system.lower() == 'windows': # no general value
    else:
        return (0, 'Unknown')

def get_computer_system_op(prefix='Linux'):
    """
    @return object path of CIM_ComputerSystem for this system
    """
    return pywbem.CIMInstanceName(
            classname='%s_ComputerSystem' % prefix,
            keybindings={
                "CreationClassName": "%s_ComputerSystem" % prefix
              , "Name" : socket.gethostname() },
            namespace="root/cimv2")

def check_target_operating_system(system):
    """
    @return if param system matches current target operating system
    """
    if isinstance(system, basestring):
        system = int(system)
    if not isinstance(system, (int, long)):
        raise TypeError("system must be either string or integer, not {}"
                .format(system.__class__.__name__))
    tos = get_target_operating_system()
    if system == tos:
        return True
    if system == 36: # linux
        if platform.system().lower() == "linux":
            return True
    if (   system >= 97 and system <= 100 # linux 2.x.x
       and platform.uname()[2].startswith('2.4' if system < 99 else '2.6')
       # check machine
       and (  bool(platform.machine().endswith('64'))
           == bool(not (system % 2)))):
        return True
    return False

def check_computer_system_op(env, system):
    """
    @param system is object path referring to CIM_ComputerSystem instance
    passed as argument to some cim function
    @return True if this instance matches our system; otherwise a CIMError
    will be raised
    """
    if not isinstance(system, pywbem.CIMInstanceName):
        raise pywbem.CIMError(pywbem.CIM_ERR_NOT_FOUND,
                "\"System\" must be a CIMInstanceName")
    our_system = get_computer_system_op('CIM')
    chandle = env.get_cimom_handle()
    if not chandle.is_subclass(system.namespace,
            sub=system.classname,
            super=our_system.classname):
        raise pywbem.CIMError(pywbem.CIM_ERR_NOT_FOUND,
                "Class of \"System\" must be a sublass of %s" %
                our_system.classname)
    if not 'CreationClassName' in system or not 'Name' in system:
        raise pywbem.CIMError(pywbem.CIM_ERR_NOT_FOUND,
                "\"System\" is missing one of keys")
    if not chandle.is_subclass(system.namespace,
            sub=system['CreationClassName'],
            super=our_system.classname):
        raise pywbem.CIMError(pywbem.CIM_ERR_NOT_FOUND,
                "CreationClassName of \"System\" must be a sublass of %s" %
                our_system.classname)
    if system['Name'] != our_system['Name']:
        raise pywbem.CIMError(pywbem.CIM_ERR_NOT_FOUND,
                "Name of \"System\" does not match \"%s\"" %
                our_system['Name'])
    return True


def match_pkg(pkg, **kwargs):
    """
    all not Null and not empty arguments will be matched against pkg
    attributes; if all of them match, return True

    possible arguments:
      name, epoch, version, release, arch
      evra, nevra
    """
    for attr in ( 'evra', 'nevra', 'name', 'epoch'
                , 'version', 'release', 'arch'):
        value = kwargs.get(attr, None)
        if value and getattr(pkg, attr) != value:
            return False
    return True

class SoftwarePackage:
    """
    Just a namespace for common function related to SoftwarePackage provider.
    TODO: make it a submodule
    """

    @staticmethod
    def object_path2pkg(env, objpath, package_list='installed'):
        """
        @param objpath must contain precise information of package,
        otherwise a CIM_ERR_NOT_FOUND error is raised
        @param package_list one of {'installed', 'all', 'available'}
        says, where to look for given package
        """
        if not isinstance(objpath, pywbem.CIMInstanceName):
            raise TypeError("objpath must be an instance of CIMInstanceName")
        if not isinstance(package_list, basestring):
            raise TypeError("package_list must be a string")
        if not package_list in ('installed', 'all', 'available'):
            raise ValueError('unsupported package list "%s"'%package_list)

        if (  not objpath['Name'] or not objpath['SoftwareElementID']
           or not objpath['SoftwareElementID'].startswith(objpath['Name'])
           or objpath['SoftwareElementID'].find(objpath['Version']) == -1):
            raise pywbem.CIMError(pywbem.CIM_ERR_NOT_FOUND, "Wrong keys.")
        if not check_target_operating_system(objpath['TargetOperatingSystem']):
            raise pywbem.CIMError(pywbem.CIM_ERR_NOT_FOUND,
                    "Wrong target operating system.")
        if not objpath['Name'] or not objpath['Version']:
            raise pywbem.CIMError(pywbem.CIM_ERR_NOT_FOUND,
                    'Both "Name" and "Version" must be given')
        match = RE_NEVRA.match(objpath['SoftwareElementID'])
        if not match:
            raise pywbem.CIMError(pywbem.CIM_ERR_NOT_FOUND,
                    "Wrong SotwareElementID. Expected valid nevra"
                    " (name-[epoch:]version-release.arch).")
        if objpath['Version'] != match.group('ver'):
            raise pywbem.CIMError(pywbem.CIM_ERR_NOT_FOUND,
                "Version does not match version part in SoftwareElementID.")
        evra = "{}:{}-{}.{}".format(*(
                (match.group(k) if k != "epoch" or match.group(k) else "0")
                            for k in ("epoch", 'ver', 'rel', 'arch')))
        with YumDB.getInstance(env) as ydb:
            pkglist = ydb.doPackageLists(package_list,
                    showdups=package_list != 'installed')
            if package_list != 'all':
                pkglist = getattr(pkglist, package_list)
            else:
                # NOTE: available ∩ installed = ∅
                pkglist = itertools.chain(pkglist.available, pkglist.installed)
            exact, _, _ = yum.packages.parsePackages(pkglist, [objpath['Name']])
            for pkg in yum.misc.unique(exact):
                if pkg.evra == evra:
                    return pkg
            raise pywbem.CIMError(pywbem.CIM_ERR_NOT_FOUND,
                "No matching package found.")

    @staticmethod
    def object_path2pkg_search(env, objpath):
        """
        similar to object_path2pkg, but tries to find best suitable
        package matching keys
        
        If any matching package is already installed, it is returned.
        Otherwise available package with highest version is returned.

        @param objpath may be object of CIMInstance or CIMInstanceName and
        must contain at least \"Name\" or \"SoftwareElementID\"
        @return instance of yum.rpmsack.RPMInstalledPackage in case of
        installed package, otherwise yum.packages.YumAvailablePackage
        """
        logger = env.get_logger()
        if isinstance(objpath, pywbem.CIMInstance):
            def _get_key(k):
                """@return value of instance's key"""
                value = objpath.properties.get(k, None)
                if isinstance(value, pywbem.CIMProperty):
                    return value.value
                if value is not None:
                    return value
                logger.log_error('missing key "{}" in inst.props'.format(k))
                return objpath.path[k] if k in objpath.path else None
        elif isinstance(objpath, pywbem.CIMInstanceName):
            _get_key = lambda k: objpath[k] if k in objpath else None
        else:
            raise TypeError("objpath must be either CIMInstance"
                            "or CIMInstanceName")

        # parse and check arguments
        match_props = {}      # args for match_pkg
        if _get_key('SoftwareElementID'):
            match = RE_NEVRA.match(_get_key('SoftwareElementID'))
            if not match:
                raise pywbem.CIMError(pywbem.CIM_ERR_INVALID_PARAMETER,
                        "SoftwareElementID could not be parsed.")
            for k in ('name', 'version', 'release', 'arch'):
                mkey = k if k not in ('version', 'release') else k[:3]
                match_props[k] = match.group(mkey)
            if not match.group("epoch"):
                match_props["epoch"] = "0"
        else:
            for k in ('name', 'epoch', 'version', 'release', 'arch'):
                ikey = k if k != 'arch' else "architecture"
                if _get_key(ikey):
                    match_props[k] = _get_key(ikey)

        if not match_props:
            raise pywbem.CIMError(pywbem.CIM_ERR_FAILED,
                    "Too few key values given (give at least a Name).")
        if not 'name' in match_props:
            raise pywbem.CIMError(pywbem.CIM_ERR_FAILED,
                    "Missing either Name or SoftwareElementID property.")

        # get available packages
        pkglist = YumDB.getInstance(env).doPackageLists('all', showdups=True)
        # NOTE: available ∩ installed = ∅
        exact, _, _ = yum.packages.parsePackages(
                itertools.chain(pkglist.available, pkglist.installed),
                [match_props['name']])
        exact = yum.misc.unique(exact)
        exact_orig = exact
        exact = sorted([ p for p in exact if match_pkg(p, **match_props) ])
        if len(exact) == 0:
            logger.log_error('could not find any package for query: {}'
                    ' in list: {}'
                .format(match_props, [p.nevra for p in exact_orig]))
            raise pywbem.CIMError(pywbem.CIM_ERR_NOT_FOUND,
                "No matching package found.")
        for pkg in exact: # check, whether package is already installed
            if isinstance(pkg, yum.rpmsack.RPMInstalledPackage):
                return pkg
        logger.log_info(('found multiple matching packages'
                    ' for query: {}' if len(exact) > 1 else
                    'exact match found for query: {}')
                    .format(match_props))
        return exact[-1] # select highest version

    @staticmethod
    def pkg2model(env, pkg, keys_only=True, model=None):
        """
        @param model if None, will be filled with data, otherwise
        a new instance of CIMInstance or CIMObjectPath is created
        """
        #if not isinstance(pkg, yum.rpmsack.RPMInstalledPackage):
        #if not isinstance(pkg, yum.packages.YumHeaderPackage):
        if not isinstance(pkg, yum.packages.YumAvailablePackage):
            raise TypeError(
                    "pkg must be an instance of YumAvailablePackage")
        if model is None:
            model = pywbem.CIMInstanceName('LMI_SoftwarePackage',
                    namespace='root/cimv2')
            if not keys_only:
                model = pywbem.CIMInstance('LMI_SoftwarePackage', path=model)
        if isinstance(model, pywbem.CIMInstance):
            def _set_key(k, value):
                """Sets the value of key property of cim instance"""
                model[k] = value
                model.path[k] = value #pylint: disable=E1103
        else:
            _set_key = model.__setitem__
        with YumDB.getInstance(env):
            _set_key('Name', pkg.name)
            _set_key('SoftwareElementID', pkg.nevra)
            _set_key('SoftwareElementState', pywbem.Uint16(2
                    if isinstance(pkg, yum.rpmsack.RPMInstalledPackage)
                    else 1))
            _set_key('TargetOperatingSystem', 
                    pywbem.Uint16(get_target_operating_system()[0]))
            _set_key('Version', pkg.version)
            if not keys_only:
                model['Caption']      = pkg.summary
                model['Description']  = pkg.description
                if isinstance(pkg, yum.rpmsack.RPMInstalledPackage):
                    model['InstallDate']  = pywbem.CIMDateTime(
                            datetime.fromtimestamp(pkg.installtime))
                if pkg.vendor:
                    model['Manufacturer'] = pkg.vendor
                model['Release']      = pkg.release
                model['Epoch']        = pywbem.Uint16(pkg.epoch)
                model["Architecture"] = pkg.arch
                model['License']      = pkg.license
                model['Group']        = pkg.group
                model['Size']         = pywbem.Uint64(pkg.size)
        return model

class SoftwareFileCheck:
    """
    Just a namespace for functions related to FileCheck provider.
    TODO: make it a submodule
    """

    passed_flags_descriptions = (
            "Existence",
            "File Type",
            "File Size",
            "File Mode",
            "File Checksum",
            "Device major/minor number",
            "Symlink Target",
            "User Ownership", "Group Ownership",
            "Modify Time")

    checksumtype_str2num = dict((val, k) for (k, val) in
            yum.constants.RPM_CHECKSUM_TYPES.items())

    @staticmethod
    def pkg_checksum_type(pkg):
        """
        @return integer representation of checksum type
        """
        if not isinstance(pkg, yum.packages.YumAvailablePackage):
            raise TypeError("pkg must be an instance of YumAvailablePackage")
        if isinstance(pkg, yum.rpmsack.RPMInstalledPackage):
            return pkg.hdr[rpm.RPMTAG_FILEDIGESTALGO]
        with YumDB.getInstance(): # ensure, that _yum is inited
            return SoftwareFileCheck.checksumtype_str2pywbem(
                    pkg.yumdb_info.checksum_type)

    @staticmethod
    def checksumtype_num2hash(csumt):
        """
        @param csumt checksum type as a number obtained from package
        @return hash function object corresponding to csumt
        """
        return getattr(hashlib, yum.constants.RPM_CHECKSUM_TYPES[csumt])

    @staticmethod
    def checksumtype_str2pywbem(alg):
        """
        @param alg is a name of algorithm used for checksum
        @return pywbem number corresponding to given alg
        """
        try:
            res = SoftwareFileCheck.checksumtype_str2num[alg.lower()]
        except KeyError:
            res = 0
        return pywbem.Uint16(res)

    @staticmethod
    def filetype_str2pywbem(file_type):
        """
        @param file_type is a name of file type obtained from pkg headers
        @return pywbem number corresponding to thus file type
        """
        try:
            return pywbem.Uint16(
                    { 'file'             : 1
                    , 'directory'        : 2
                    , 'symlink'          : 3
                    , 'fifo'             : 4
                    , 'character device' : 5
                    , 'block device'     : 6
                    }[file_type])
        except KeyError:
            return pywbem.Uint16(0)

    @staticmethod
    def filetype_mode2pywbem(mode):
        """
        @param mode is a raw file mode as integer
        @return pywbem numeric value of file's type
        """
        for i, name in enumerate(
                ('REG', 'DIR', 'LNK', 'FIFO', 'CHR', 'BLK'), 1):
            if getattr(stat, 'S_IS' + name)(mode): 
                return pywbem.Uint16(i)
        return pywbem.Uint16(0)

    @staticmethod
    def mode2pywbem_flags(mode):
        """
        @param mode if None, file does not exist
        @return list of integer flags describing file's access permissions
        """
        if mode is None:
            return None
        flags = []
        for i, flag in enumerate((
                stat.S_IXOTH,
                stat.S_IWOTH,
                stat.S_IROTH,
                stat.S_IXGRP,
                stat.S_IWGRP,
                stat.S_IRGRP,
                stat.S_IXUSR,
                stat.S_IWUSR,
                stat.S_IRUSR,
                stat.S_ISVTX,
                stat.S_ISGID,
                stat.S_ISUID)):
            if flag & mode:
                flags.append(pywbem.Uint8(i))
        return flags

    @staticmethod
    def hashfile(afile, hashers, blocksize=65536):
        """
        @param hashers is a list of hash objects
        @return list of digest strings (in hex format) for each hash object
        given in the same order
        """
        if not isinstance(hashers, (tuple, list, set, frozenset)):
            hashers = (hashers, )
        buf = afile.read(blocksize)
        while len(buf) > 0:
            for hashfunc in hashers:
                hashfunc.update(buf)
            buf = afile.read(blocksize)
        return [ hashfunc.hexdigest() for hashfunc in hashers ]

    @staticmethod
    def compute_checksums(env, checksum_type, file_type, file_path):
        """
        @param file_type is not a file, then zeroes are returned
        @param checksum_type selected hash algorithm to compute second
        checksum
        @return (md5sum, checksum)
        both checksums are computed from file_path's content
        first one is always md5, the second one depends on checksum_type
        if file does not exists, (None, None) is returned
        """
        hashers = [hashlib.md5()]   #pylint: disable=E1101
        if checksum_type != SoftwareFileCheck.checksumtype_str2num["md5"]:
            hashers.append(SoftwareFileCheck.checksumtype_num2hash(
                checksum_type)())
        if file_type != SoftwareFileCheck.filetype_str2pywbem('file'):
            rslts = ['0'*len(h.hexdigest()) for h in hashers]
        else:
            try:
                with open(file_path, 'rb') as fobj:
                    rslts = SoftwareFileCheck.hashfile(fobj, hashers)
            except (OSError, IOError) as exc:
                env.get_logger().log_error("could not open file \"%s\""
                        " for reading: %s" % (file_path, exc))
                return None, None
        return (rslts[0], rslts[1] if len(rslts) > 1 else rslts[0]*2)

    @staticmethod
    def object_path2yumcheck(env, objpath):
        """
        @return instance of yum.packages._RPMVerifyPackage
        this object holds RPMInstalledPackage under its po attribute
        """
        if not isinstance(objpath, pywbem.CIMInstanceName):
            raise TypeError("objpath must be instance of CIMInstanceName, "
                    "not \"%s\"" % objpath.__class__.__name__)

        if (  not objpath['Name'] or not objpath['SoftwareElementID']
           or not objpath['CheckID']
           or not objpath['CheckID'].endswith('#'+objpath['Name'])
           or objpath['SoftwareElementID'].find(objpath['Version']) == -1):
            raise pywbem.CIMError(pywbem.CIM_ERR_NOT_FOUND, "Wrong keys.")
        if objpath['SoftwareElementState'] not in ("2", 2):
            raise pywbem.CIMError(pywbem.CIM_ERR_NOT_FOUND,
                    "Only \"Executable\" software element state supported")
        if not check_target_operating_system(objpath['TargetOperatingSystem']):
            raise pywbem.CIMError(pywbem.CIM_ERR_NOT_FOUND,
                    "Wrong target operating system.")
        if not objpath['Name'] or not objpath['Version']:
            raise pywbem.CIMError(pywbem.CIM_ERR_NOT_FOUND,
                    'Both "Name" and "Version" must be given')
        match = RE_NEVRA.match(objpath['SoftwareElementID'])
        if not match:
            raise pywbem.CIMError(pywbem.CIM_ERR_NOT_FOUND,
                    "Wrong SotwareElementID. Expected valid nevra"
                    " (name-epoch:version-release.arch).")
        if objpath['Version'] != match.group('ver'):
            raise pywbem.CIMError(pywbem.CIM_ERR_NOT_FOUND,
                "Version does not match version part in SoftwareElementID.")

        evra = "{}:{}-{}.{}".format(*(
                (match.group(k) if k != "epoch" or match.group(k) else "0")
                            for k in ("epoch", 'ver', 'rel', 'arch')))
        with YumDB.getInstance(env) as ydb:
            pkglist = ydb.doPackageLists('installed')
            exact, _, _ = yum.packages.parsePackages(
                    pkglist.installed, [match.group('name')])
            for pkg in yum.misc.unique(exact):
                if pkg.evra != evra:
                    continue
                vpkg = yum.packages._RPMVerifyPackage(
                        pkg, pkg.hdr.fiFromHeader(),
                        SoftwareFileCheck.pkg_checksum_type(pkg), [], True)
                if not objpath['Name'] in vpkg:
                    raise pywbem.CIMError(pywbem.CIM_ERR_NOT_FOUND,
                            "File not found in RPM package.")
                return vpkg
            raise pywbem.CIMError(pywbem.CIM_ERR_NOT_FOUND,
                    "No matching package installed.")

    # Named tuple to store results of rpm file check as pywbem values,
    # all results are in form:
    # (expected, reality)
    # where
    # expected is value from rpm package
    # reality  is value obtained from installed file
    # None means, that value could not be obtained
    # except for "exists" and "md5_checksum" attributes, where "exists"
    # is boolean and md5_checksum is a string
    # for example:
    # file_check.file_type == (4, 3)
    FileCheck = collections.namedtuple('FileCheck',
            'exists, md5_checksum, file_type, file_size, file_mode, '
            'file_checksum, device, link_target, user_id, group_id, '
            'last_modification_time')

    @staticmethod
    def test_file(env, checksum_type, vpf):
        """
        @param checksum type is a pywbem value for ChecksumType property
        @return instance of FileCheck
        """
        if not isinstance(vpf, yum.packages._RPMVerifyPackageFile):
            raise TypeError("vpf must be an instance of _RPMVerifyPackage,"
            " not \"%s\"" % vpf.__class__.__name__)
        exists = os.path.lexists(vpf.filename)
        md5_checksum = None
        expected = {
            "file_type"     : SoftwareFileCheck.filetype_str2pywbem(vpf.ftype),
            "user_id"       : pywbem.Uint32(pwd.getpwnam(vpf.user).pw_uid),
            "group_id"      : pywbem.Uint32(grp.getgrnam(vpf.group).gr_gid),
            "file_mode"     : pywbem.Uint32(vpf.mode),
            "file_size"     : pywbem.Uint64(vpf.size),
            "link_target"   : vpf.readlink if vpf.readlink else None,
            "file_checksum" : vpf.digest[1],
            "device"        : (pywbem.Uint64(vpf.dev)
                if vpf.ftype.endswith('device') else None),
            "last_modification_time" : pywbem.Uint64(vpf.mtime)
        }
        if not exists:
            reality = collections.defaultdict(lambda: None)
        else:
            fstat = os.lstat(vpf.filename)
            reality = {
                "file_type" : SoftwareFileCheck.filetype_mode2pywbem(
                    fstat.st_mode),
                "user_id"   : pywbem.Uint32(fstat.st_uid),
                "group_id"  : pywbem.Uint32(fstat.st_gid),
                "file_mode" : pywbem.Uint32(fstat.st_mode),
                "file_size" : pywbem.Uint64(fstat.st_size),
                "last_modification_time" : pywbem.Uint64(fstat.st_mtime)
            }
            reality["device"] = (pywbem.Uint64(fstat.st_dev)
                if reality['file_type'] ==
                    SoftwareFileCheck.filetype_str2pywbem("device") else None)
            reality["link_target"] = (os.readlink(vpf.filename)
                     if os.path.islink(vpf.filename) else None)
            md5_checksum, checksum = SoftwareFileCheck.compute_checksums(
                    env, checksum_type, reality["file_type"], vpf.filename)
            reality["file_checksum"] = checksum
        kwargs = dict(exists=exists, md5_checksum=md5_checksum,
                **dict((k, (expected[k], reality[k])) for k in expected))
        return SoftwareFileCheck.FileCheck(**kwargs)

    @staticmethod
    def filecheck_passed(file_check):
        """
        @return True if installed file passed all checks.
        """
        if not isinstance(file_check, SoftwareFileCheck.FileCheck):
            raise TypeError("file_check must be an instance of FileCheck")
        return (   file_check.exists
               and all(   val[0] == val[1]
                      #pylint: disable=W0212
                      for k, val in file_check._asdict().items()
                      if (   isinstance(val, tuple)
                         and (  k != "last_modification_time"
                             or file_check.file_type[0] == \
                                SoftwareFileCheck.filetype_str2pywbem("file")
                             ))))

    @staticmethod
    def _filecheck2model_flags(file_check):
        """
        @param file_check is an instance of FileCheck
        @return pywbem value for PassedFlags property
        """
        flags = []
        for k, value in file_check._asdict().items(): #pylint: disable=W0212
            if isinstance(value, tuple):
                if (  k != "last_modification_time"
                   or file_check.file_type[0] ==
                        SoftwareFileCheck.filetype_str2pywbem('file')):
                    # last_modification_time check is valid only for
                    # regular files
                    flag = file_check.exists and value[0] == value[1]
                else:
                    flag = True
                flags.append(flag)
            elif isinstance(value, bool):
                flags.append(value)
        return flags

    @staticmethod
    def _fill_non_key_values(env, model, pkg, vpf, file_check):
        """
        Fills a non key values into instance of SoftwareFileCheck.
        """
        model['FileName'] = os.path.basename(vpf.filename)
        model['FileChecksumType'] = csumt = \
                pywbem.Uint16(SoftwareFileCheck.pkg_checksum_type(pkg))
        if file_check is None:
            file_check = SoftwareFileCheck.test_file(env, csumt, vpf)
        for mattr, fattr in (
                ('FileType', 'file_type'),
                ('FileUserID', 'user_id'),
                ('FileGroupID', 'group_id'),
                ('FileMode', 'file_mode'),
                ('LastModificationTime', 'last_modification_time'),
                ('FileSize', 'file_size'),
                ('LinkTarget', 'link_target'),
                ('FileChecksum', 'file_checksum')):
            exp, rea = getattr(file_check, fattr)
            if exp is not None:
                model['Expected' + mattr] = exp
            if rea is not None:
                model[mattr] = rea
        model['ExpectedFileModeFlags'] = \
                SoftwareFileCheck.mode2pywbem_flags(file_check.file_mode[0])
        if file_check.exists:
            model['FileModeFlags'] = \
                SoftwareFileCheck.mode2pywbem_flags(file_check.file_mode[1])
        model['FileExists'] = file_check.exists
        if file_check.md5_checksum is not None:
            model['MD5Checksum'] = file_check.md5_checksum
        model['PassedFlags'] = SoftwareFileCheck._filecheck2model_flags(
                file_check)
        model['PassedFlagsDescriptions'] = list(
                SoftwareFileCheck.passed_flags_descriptions)

    @staticmethod
    def filecheck2model(vpkg, file_name, env, keys_only=True,
            model=None, file_check=None):
        """
        @param vpkg is an instance of yum.packages_RPMVerifyPackage
        @param file_name a absolute file path contained in package
        @param keys_only if True, then only key values will be filed
        @param model if given, then this instance will be modified and
        returned
        @param file_check if not given, it will be computed
        @return instance of LMI_SoftwareFileCheck class with all desired
        values filed
        """
        if not isinstance(vpkg, yum.packages._RPMVerifyPackage):
            raise TypeError(
                    "vpkg must be an instance of _RPMVerifyPackage")
        if not file_name in vpkg:
            raise pywbem.CIMError(pywbem.CIM_ERR_NOT_FOUND,
                    "File \"%s\" not found among package files" % file_name)
        if model is None:
            model = pywbem.CIMInstanceName("LMI_SoftwareFileCheck",
                    namespace="root/cimv2")
            if not keys_only:
                model = pywbem.CIMInstance("LMI_SoftwareFileCheck", path=model)
        if file_check is not None:
            if not isinstance(file_check, SoftwareFileCheck.FileCheck):
                raise TypeError("file_check must be an instance of FileCheck")
        pkg = vpkg.po
        vpf = vpkg._files[file_name]
        model['Name'] = vpf.filename
        model['SoftwareElementID'] = pkg.nevra
        model['SoftwareElementState'] = pywbem.Uint16(2)
        model['TargetOperatingSystem'] = pywbem.Uint16(
                get_target_operating_system()[0])
        model['Version'] = pkg.version
        model['CheckID'] = '%s#%s' % (pkg.name, vpf.filename)
        if not keys_only:
            SoftwareFileCheck._fill_non_key_values(
                    env, model, pkg, vpf, file_check)
        return model