#    Back In Time
#    Copyright (C) 2008-2017 Oprea Dan, Bart de Koning, Richard Bailey, Germar Reitze
#
#    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; either version 2 of the License, or
#    (at your option) any later version.
#
#    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.,
#    51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.


import os
import sys
import subprocess
import signal
import re
import errno
import gzip
import tempfile
import atexit
from datetime import datetime
from distutils.version import StrictVersion
from time import sleep
keyring = None
keyring_warn = False
try:
    if os.getenv('BIT_USE_KEYRING', 'true') == 'true' and os.geteuid() != 0:
        import keyring
except:
    keyring = None
    os.putenv('BIT_USE_KEYRING', 'false')
    keyring_warn = True

# getting dbus imports to work in Travis CI is a huge pain
# use conditional dbus import
ON_TRAVIS = 'TRAVIS' in os.environ and os.environ['TRAVIS'] == 'true'
try:
    import dbus
except ImportError:
    if ON_TRAVIS:
        #python-dbus doesn't work on Travis yet.
        dbus = None
    else:
        raise

import configfile
import logger
from applicationinstance import ApplicationInstance
from exceptions import Timeout, InvalidChar, PermissionDeniedByPolicy

ON_AC = 0
ON_BATTERY = 1
POWER_ERROR = 255

DISK_BY_UUID = '/dev/disk/by-uuid'

def get_share_path():
    share = os.path.abspath(os.path.join(__file__, os.pardir, os.pardir, os.pardir))
    if os.path.basename(share) == 'share':
        return share
    else:
        return '/usr/share'

def get_backintime_path(*path):
    return os.path.abspath(os.path.join(__file__, os.pardir, os.pardir, *path))

def register_backintime_path(*path):
    '''find duplicate in qt4/qt4tools.py
    '''
    path = get_backintime_path(*path)
    if not path in sys.path:
        sys.path.insert(0, path)

def running_from_source():
    '''return True if BackInTime was started
    from source folder (without installing)
    '''
    return os.path.isfile(get_backintime_path('common', 'backintime'))

def add_source_to_path_environ():
    source = get_backintime_path('common')
    path = os.getenv('PATH')
    if source not in path.split(':'):
        os.environ['PATH'] = '%s:%s' %(source, path)

def get_git_ref_hash():
    ref, hashid = None, None
    gitPath = os.path.abspath(os.path.join(__file__, os.pardir, os.pardir, '.git'))
    headPath = os.path.join(gitPath, 'HEAD')
    refPath = ''
    if not os.path.isdir(gitPath):
        return (ref, hashid)
    try:
        with open(headPath, 'rt') as f:
            refPath = f.read().strip('\n')
            if refPath.startswith('ref: '):
                refPath = refPath[5:]
            if refPath:
                refPath = os.path.join(gitPath, refPath)
                ref = os.path.basename(refPath)
    except Exception as e:
        pass
    if os.path.isfile(refPath):
        try:
            with open(refPath, 'rt') as f:
                hashid = f.read().strip('\n')
        except:
            pass
    return (ref, hashid[:7])

def read_file( path, default_value = None ):
    ret_val = default_value

    try:
        if os.path.exists(path):
            with open( path ) as f:
                ret_val = f.read()
        elif os.path.exists(path + '.gz'):
            with gzip.open(path + '.gz') as f:
                ret_val = f.read().decode()
    except:
        pass

    return ret_val

def read_file_lines( path, default_value = None ):
    ret_val = default_value

    try:
        if os.path.exists(path):
            with open( path ) as f:
                ret_val = f.readlines()
        elif os.path.exists(path + '.gz'):
            with gzip.open(path + '.gz') as f:
                ret_val = [b.decode() for b in f.readlines()]
    except:
        pass

    return ret_val


def read_command_output( cmd ):
    ret_val = ''

    try:
        pipe = os.popen( cmd )
        ret_val = pipe.read().strip()
        pipe.close()
    except:
        return ''

    return ret_val


def check_command( cmd ):
    cmd = cmd.strip()

    if not cmd:
        return False

    if os.path.isfile( cmd ):
        return True
    return not which(cmd) is None

def which(filename):
    """Checks if 'filename' is present in the system PATH."""
    pathenv = os.getenv('PATH', '')
    path = pathenv.split(":")
    path.insert(0, os.getcwd())
    for directory in path:
        fullpath = os.path.join(directory, filename)
        if os.path.isfile(fullpath) and os.access(fullpath, os.X_OK):
            return fullpath
    return None

def make_dirs( path ):
    path = path.rstrip( os.sep )
    if not path:
        return False

    if os.path.isdir(path):
        return True
    else:
        try:
            os.makedirs( path )
        except Exception as e:
            logger.error("Failed to make dirs '%s': %s"
                         %(path, str(e)), traceDepth = 1)
    return os.path.isdir(path)

def process_exists( name ):
    output = read_command_output( "ps -o pid= -C %s" % name )
    return len( output ) > 0


def check_x_server():
    return 0 == os.system( 'xdpyinfo >/dev/null 2>&1' )


def prepare_path( path ):
    path = path.strip( "/" )
    path = os.sep + path
    return path


def power_status_available():
    """Uses the on_ac_power command to detect if the the system is able
    to return the power status."""
    try:
        rt = subprocess.call( 'on_ac_power' )
        if rt == ON_AC or rt == ON_BATTERY:
            return True
    except:
        pass
    return False


def on_battery():
    """Checks if the system is on battery power."""
    if power_status_available ():
        return subprocess.call ( 'on_ac_power' ) == ON_BATTERY
    else:
        return False


def get_snapshots_list_in_folder( folder, sort_reverse = True ):
    biglist = []

    try:
        biglist = os.listdir( folder )
    except:
        pass

    list_ = []

    for item in biglist:
        if len( item ) != 15 and len( item ) != 19:
            continue
        if os.path.isdir( os.path.join( folder, item, 'backup' ) ):
            list_.append( item )

    list_.sort( reverse = sort_reverse )
    return list_


def get_nonsnapshots_list_in_folder( folder, sort_reverse = True ):
    biglist = []

    try:
        biglist = os.listdir( folder )
    except:
        pass

    list_ = []

    for item in biglist:
        if len( item ) != 15 and len( item ) != 19:
            list_.append( item )
        else:
            if os.path.isdir( os.path.join( folder, item, 'backup' ) ):
                continue
            else:
                list_.append( item )

    list_.sort( reverse = sort_reverse )
    return list_


def move_snapshots_folder( old_folder, new_folder ):
    '''Moves all the snapshots from one folder to another'''
    print("\nMove snapshots from %s to %s" %( old_folder, new_folder ))

    # Fetch a list with snapshots for verification
    snapshots_to_move = get_snapshots_list_in_folder( old_folder )
    snapshots_already_there = []
    if os.path.exists( new_folder ) == True:
        snapshots_already_there = get_snapshots_list_in_folder( new_folder )
    else:
        make_dirs( new_folder )
    print("To move: %s" % snapshots_to_move)
    print("Already there: %s" % snapshots_already_there)
    snapshots_expected = snapshots_to_move + snapshots_already_there
    print("Snapshots expected: %s" % snapshots_expected)

    # Check if both folders are within the same os
    device_old = os.stat( old_folder ).st_dev
    device_new = os.stat( new_folder ).st_dev
    if device_old == device_new:
        # Use move
        for snapshot in snapshots_to_move:
            cmd = "mv -f \"%s/%s\" \"%s\"" %( old_folder, snapshot, new_folder )
            _execute( cmd )
    else:
        # Use rsync
        # Prepare hardlinks
        if snapshots_already_there:
            first_snapshot_path = os.path.join( new_folder, snapshots_to_move[ len( snapshots_to_move ) - 1 ] )
            snapshot_to_hardlink_path =  os.path.join( new_folder, snapshots_already_there[0] )
            _execute( "find \"%s\" -type d -exec chmod u+wx {} \\;" % snapshot_to_hardlink_path )
            cmd = "cp -al \"%s\" \"%s\"" % ( snapshot_to_hardlink_path, first_snapshot_path )
            _execute( cmd )

        # Prepare excludes
        nonsnapshots = get_nonsnapshots_list_in_folder( old_folder )
        print("Nonsnapshots: %s" % nonsnapshots)
        items = []
        for nonsnapshot in nonsnapshots:
            for item in items:
                if nonsnapshot == item:
                    break
            items.append( "--exclude=\"%s\"" % nonsnapshot )
        rsync_exclude = ' '.join( items )

        # Move move move
        cmd = "rsync -aEAXHv --delete " + old_folder + " " + new_folder + " " + rsync_exclude
        _execute( cmd )
        _execute ( "find \"%s\" \"%s\" -type d -exec chmod a-w {} \\;" % ( snapshot_to_hardlink_path, first_snapshot_path ) )

    # Remove old ones
    snapshots_not_moved = []
    for snapshot in snapshots_to_move:
        if os.path.exists( os.path.join( new_folder, snapshot, "backup" ) ):
            if os.path.exists( os.path.join( old_folder, snapshot) ):
                print("Remove: %s" %snapshot)
                path_to_remove = os.path.join( old_folder, snapshot )
                cmd = "find \"%s\" -type d -exec chmod u+wx {} \\;" % path_to_remove #Debian patch
                _execute( cmd )
                cmd = "rm -rfv \"%s\"" % path_to_remove
                _execute( cmd )
            else:
                print("%s was already removed" %snapshot)
        else:
            snapshots_not_moved.append( snapshot )

    # Check snapshot list
    if snapshots_not_moved:
        print("Error! Not moved: %s\n" %snapshots_not_moved)
        return False
    print("Succes!\n")
    return True

def _execute( cmd, callback = None, user_data = None ):
    logger.debug("Call command \"%s\"" %cmd, traceDepth = 1)
    ret_val = 0

    if callback is None:
        ret_val = os.system( cmd )
    else:
        pipe = os.popen( cmd, 'r' )

        while True:
            line = temp_failure_retry( pipe.readline )
            if not line:
                break
            callback( line.strip(), user_data )

        ret_val = pipe.close()
        if ret_val is None:
            ret_val = 0

    if ret_val != 0:
        logger.warning("Command \"%s\" returns %s"
                       %(cmd, ret_val),
                       traceDepth = 1)
    else:
        logger.debug("Command \"%s...\" returns %s"
                     %(cmd[:min(16, len(cmd))], ret_val),
                     traceDepth = 1)

    return ret_val


def is_process_alive( pid ):
    try:
        os.kill( pid, 0 )	#this will raise an exception if the pid is not valid
    except:
        return False

    return True


def get_rsync_caps():
    data = read_command_output( 'rsync --version' )
    caps = []
    #rsync >= 3.1 does provide --info=progress2
    m = re.match(r'rsync\s*version\s*(\d\.\d)', data)
    if m and StrictVersion(m.group(1)) >= StrictVersion('3.1'):
        caps.append('progress2')
    si = data.find( 'Capabilities:' )
    if si < 0:
        return caps
    si = data.find( '\n', si )
    if si < 0:
        return caps
    ei = data.find( '\n\n', si )
    if ei < 0:
        return caps

    data = data[ si + 1 : ei - 1 ]
    data = data.split( '\n' )
    all_caps = ''

    for line in data:
        line = line.strip()
        if not line:
            continue
        if all_caps:
            all_caps = all_caps + ' '
        all_caps = all_caps + line

    caps.extend(all_caps.split( ", " ))
    return caps


def use_rsync_fast( config ):
    return not (config.preserve_acl() or config.preserve_xattr())


def get_rsync_prefix( config, no_perms = True, use_modes = ['ssh', 'ssh_encfs'] ):
    caps = get_rsync_caps()
    cmd = ''
    if config.is_run_nocache_on_local_enabled():
        cmd += 'nocache '
    cmd += 'rsync'
    cmd += ' -rtDHh'

    if config.use_checksum() or config.force_use_checksum:
        cmd = cmd + ' --checksum'

    if config.copy_unsafe_links():
        cmd = cmd + ' --copy-unsafe-links'

    if config.copy_links():
        cmd = cmd + ' --copy-links'
    else:
        cmd = cmd + ' --links'

    if config.preserve_acl() and "ACLs" in caps:
        cmd = cmd + ' -A'
        no_perms = False

    if config.preserve_xattr() and "xattrs" in caps:
        cmd = cmd + ' -X'
        no_perms = False

    if no_perms:
        cmd = cmd + ' --no-p --no-g --no-o'
    else:
        cmd = cmd + ' -pEgo'

    if 'progress2' in caps:
        cmd += ' --info=progress2 --no-i-r'

    if config.rsync_options_enabled():
        cmd += ' ' + config.rsync_options()

    mode = config.get_snapshots_mode()
    if mode in ['ssh', 'ssh_encfs'] and mode in use_modes:
        ssh_port = config.get_ssh_port()
        ssh_cipher = config.get_ssh_cipher()
        if ssh_cipher == 'default':
            ssh_cipher_suffix = ''
        else:
            ssh_cipher_suffix = '-c %s' % ssh_cipher
        # specifying key file here allows to override for potentially
        # conflicting .ssh/config key entry
        ssh_private_key = "-o IdentityFile=%s" % config.get_ssh_private_key_file()
        cmd += ' --rsh="ssh -p %s %s %s"' % ( str(ssh_port), ssh_cipher_suffix, ssh_private_key)

        if config.bwlimit_enabled():
            cmd = cmd + ' --bwlimit=%d' % config.bwlimit()

        if config.is_run_nice_on_remote_enabled()     \
          or config.is_run_ionice_on_remote_enabled() \
          or config.is_run_nocache_on_remote_enabled():
            cmd += ' --rsync-path="'
            if config.is_run_nice_on_remote_enabled():
                cmd += 'nice -n 19 '
            if config.is_run_ionice_on_remote_enabled():
                cmd += 'ionice -c2 -n7 '
            if config.is_run_nocache_on_remote_enabled():
                cmd += 'nocache '
            cmd += 'rsync"'

    return cmd + ' '

def temp_failure_retry(func, *args, **kwargs):
    while True:
        try:
            return func(*args, **kwargs)
        except (os.error, IOError) as ex:
            if ex.errno == errno.EINTR:
                continue
            else:
                raise

def _get_md5sum_from_path(path):
    '''return md5sum of path, af available system command md5sum()'''
    if check_command("md5sum"):
        status,output = subprocess.getstatusoutput("md5sum '" + path + "'")
        if status == 0:
            md5sum = output.split(" ")[0]
            return md5sum
    # md5sum unavailable or command failed; raise an exception ? a message ? use std lib ?
    print("warning: md5sum() fail ! used (st_size, st_mttime) instead of md5sum.")
    obj  = os.stat(path)
    unique_key = (obj.st_size, int(obj.st_mtime))
    return unique_key

def check_cron_pattern(s):
    '''check if s look like '0,10,13,15,17,20,23' or '*/6' '''
    if s.find(' ') >= 0:
        return False
    try:
        if s.startswith('*/'):
            if int(s[2:]) <= 24:
                return True
            else:
                return False
        list_ = s.split(',')
        for s in list_:
            if int(s) <= 24:
                continue
            else:
                return False
        return True
    except ValueError:
        return False

def check_home_encrypt():
    '''return True if users home is encrypted'''
    home = os.path.expanduser('~')
    if not os.path.ismount(home):
        return False
    if check_command('ecryptfs-verify'):
        try:
            subprocess.check_call(['ecryptfs-verify', '--home'],
                                    stdout=open(os.devnull, 'w'),
                                    stderr=open(os.devnull, 'w'))
        except subprocess.CalledProcessError:
            pass
        else:
            return True
    if check_command('encfs'):
        proc = subprocess.Popen(['mount'], stdout=subprocess.PIPE, universal_newlines = True)
        mount = proc.communicate()[0]
        r = re.compile('^encfs on %s type fuse' % home)
        for line in mount.split('\n'):
            if r.match(line):
                return True
    return False

def load_env(f):
    env = os.environ.copy()
    env_file = configfile.ConfigFile()
    env_file.load(f, maxsplit = 1)
    for key in env_file.get_keys():
        value = env_file.get_str_value(key)
        if not value:
            continue
        if not key in list(env.keys()):
            os.environ[key] = value
    del(env_file)

def save_env(f):
    """
    save environ variables to file that are needed by cron
    to connect to keyring. This will only work if the user is logged in.
    """
    env = os.environ.copy()
    env_file = configfile.ConfigFile()
    for i in ('GNOME_KEYRING_CONTROL', 'DBUS_SESSION_BUS_ADDRESS', \
              'DBUS_SESSION_BUS_PID', 'DBUS_SESSION_BUS_WINDOWID', \
              'DISPLAY', 'XAUTHORITY', 'GNOME_DESKTOP_SESSION_ID', \
              'KDE_FULL_SESSION'):
        set_env_key(env, env_file, i)

    env_file.save(f)
    del(env_file)

def set_env_key(env, env_file, key):
    if key in env:
        env_file.set_str_value(key, env[key])

def keyring_supported():
    if keyring is None:
        logger.debug('No keyring due to import errror.')
        return False
    backends = []
    try: backends.append(keyring.backends.SecretService.Keyring)
    except: pass
    try: backends.append(keyring.backends.Gnome.Keyring)
    except: pass
    try: backends.append(keyring.backends.kwallet.Keyring)
    except: pass
    try: backends.append(keyring.backends.kwallet.DBusKeyring)
    except: pass
    try: backends.append(keyring.backend.SecretServiceKeyring)
    except: pass
    try: backends.append(keyring.backend.GnomeKeyring)
    except: pass
    try: backends.append(keyring.backend.KDEKWallet)
    except: pass
    try:
        displayName = keyring.get_keyring().__module__
    except:
        displayName = str(keyring.get_keyring())
    if backends and isinstance(keyring.get_keyring(), tuple(backends)):
        logger.debug("Found appropriate keyring '{}'".format(displayName))
        return True
    logger.debug("No appropriate keyring found. '{}' can't be used with BackInTime".format(displayName))
    return False

def get_password(*args):
    if not keyring is None:
        return keyring.get_password(*args)
    return None

def set_password(*args):
    if not keyring is None:
        return keyring.set_password(*args)
    return False

def get_mountpoint(path):
    '''return MOUNTPOINT for given PATH'''
    path = os.path.realpath(os.path.abspath(path))
    while path != os.path.sep:
        if os.path.ismount(path):
            return path
        path = os.path.abspath(os.path.join(path, os.pardir))
    return path

def get_mount_args(path):
    '''return a tuple of mount arguments from /proc/mounts'''
    mp = get_mountpoint(path)
    with open('/etc/mtab', 'r') as mounts:
        for line in mounts:
            args = line.strip('\n').split(' ')
            if len(args) >= 2 and args[1] == mp:
                return args
    return None

def get_device(path):
    '''return DEVICE for given PATH'''
    args = get_mount_args(path)
    if args:
        return args[0]
    return None

def get_filesystem(path):
    '''return FILESYSTEM for given PATH'''
    args = get_mount_args(path)
    if args and len(args) >= 3:
        return args[2]
    return None

def get_uuid(dev):
    '''return uuid for given block device'''
    if dev and os.path.exists(dev):
        dev = os.path.realpath(dev)
        for uuid in os.listdir(DISK_BY_UUID):
            if dev == os.path.realpath(os.path.join(DISK_BY_UUID, uuid)):
                return uuid
    c = re.compile(b'.*?ID_FS_UUID=(\S+)')
    try:
        udevadm = subprocess.check_output(['udevadm', 'info', '--name=%s' % dev])
        for line in udevadm.split():
            m = c.match(line)
            if m:
                return m.group(1).decode('UTF-8')
    except:
        pass
    return None

def get_uuid_from_path(path):
    return get_uuid(get_device(path))

def wrap_line(msg, size=950, delimiters='\t ', new_line_indicator = 'CONTINUE: '):
    if len(new_line_indicator) >= size - 1:
        new_line_indicator = ''
    while msg:
        if len(msg) <= size:
            yield(msg)
            break
        else:
            line = ''
            for look in range(size-1, size//2, -1):
                if msg[look] in delimiters:
                    line, msg = msg[:look+1], new_line_indicator + msg[look+1:]
                    break
            if not line:
                line, msg = msg[:size], new_line_indicator + msg[size:]
            yield(line)

def syncfs():
    """writes any data buffered in memory out to disk
    """
    if check_command('sync'):
        return(_execute('sync') == 0)

def update_cached_fs(dir):
    """changes not made through sshfs on remote files will not be recognized
    immediately because of the local cache. But writing a new file into that
    folder will update local cache.
    """
    with tempfile.NamedTemporaryFile('w', dir = dir) as f:
        f.write('foo')

def isRoot():
    return os.geteuid() == 0

def usingSudo():
    return isRoot() and os.getenv('HOME', '/root') != '/root'

re_wildcard = re.compile(r'(?:\[|\]|\?|\*)')
re_separate_asterisk = re.compile(r'(?:^\*+[^/\*]|[^/\*]\*+[^/\*]|[^/\*]\*+|\*+[^/\*]|[^/\*]\*+$)')

def patternHasNotEncryptableWildcard(pattern):
    '''return True if path has wildcards [ ] ? *
    but return False for foo/*, foo/*/bar, */bar or **/bar
    '''
    if not re_wildcard.search(pattern) is None:
        if re_separate_asterisk.search(pattern) is None:
            return False
        return True
    return False

BIT_TIME_FORMAT = '%Y%m%d %H%M'
ANACRON_TIME_FORMAT = '%Y%m%d'

def readTimeStamp(f):
    '''read date string from file and try to return datetime'''
    if not os.path.exists(f):
        return
    with open(f, 'r') as f:
        s = f.read().strip('\n')
    for i in (ANACRON_TIME_FORMAT, BIT_TIME_FORMAT):
        try:
            return datetime.strptime(s, i)
        except ValueError:
            pass

def writeTimeStamp(f):
    '''write current date into file'''
    make_dirs(os.path.dirname(f))
    with open(f, 'w') as f:
        f.write(datetime.now().strftime(BIT_TIME_FORMAT))

INHIBIT_LOGGING_OUT = 1
INHIBIT_USER_SWITCHING = 2
INHIBIT_SUSPENDING = 4
INHIBIT_IDLE = 8

INHIBIT_DBUS = (
               {'service':      'org.gnome.SessionManager',
                'objectPath':   '/org/gnome/SessionManager',
                'methodSet':    'Inhibit',
                'methodUnSet':  'Uninhibit',
                'interface':    'org.gnome.SessionManager',
                'arguments':    (0, 1, 2, 3)
               },
               {'service':      'org.mate.SessionManager',
                'objectPath':   '/org/mate/SessionManager',
                'methodSet':    'Inhibit',
                'methodUnSet':  'Uninhibit',
                'interface':    'org.mate.SessionManager',
                'arguments':    (0, 1, 2, 3)
               },
               {'service':      'org.freedesktop.PowerManagement',
                'objectPath':   '/org/freedesktop/PowerManagement/Inhibit',
                'methodSet':    'Inhibit',
                'methodUnSet':  'UnInhibit',
                'interface':    'org.freedesktop.PowerManagement.Inhibit',
                'arguments':    (0, 2)
               } )

def inhibitSuspend( app_id = sys.argv[0],
                    toplevel_xid = None,
                    reason = 'take snapshot',
                    flags = INHIBIT_SUSPENDING | INHIBIT_IDLE):
    '''Prevent machine to go to suspend or hibernate.
    Returns the inhibit cookie which is used to end the inhibitor.
    '''
    if not app_id:
        app_id = 'backintime'
    if not toplevel_xid:
        toplevel_xid = 0

    for dbus_props in INHIBIT_DBUS:
        try:
            #connect directly to the socket instead of dbus.SessionBus because
            #the dbus.SessionBus was initiated before we loaded the environ
            #variables and might not work
            if 'DBUS_SESSION_BUS_ADDRESS' in os.environ:
                bus = dbus.bus.BusConnection(os.environ['DBUS_SESSION_BUS_ADDRESS'])
            else:
                bus = dbus.SessionBus()
            interface = bus.get_object(dbus_props['service'], dbus_props['objectPath'])
            proxy = interface.get_dbus_method(dbus_props['methodSet'], dbus_props['interface'])
            cookie = proxy(*[ (app_id, dbus.UInt32(toplevel_xid), reason, dbus.UInt32(flags))[i] for i in dbus_props['arguments'] ])
            logger.info('Inhibit Suspend started. Reason: %s' % reason)
            return (cookie, bus, dbus_props)
        except dbus.exceptions.DBusException:
            pass
    if isRoot():
        logger.debug("Inhibit Suspend failed because BIT was started as root.")
        return
    logger.warning('Inhibit Suspend failed.')

def unInhibitSuspend(cookie, bus, dbus_props):
    '''Release inhibit.
    '''
    assert isinstance(cookie, int), 'cookie is not int type: %s' % cookie
    assert isinstance(bus, dbus.bus.BusConnection), 'bus is not dbus.bus.BusConnection type: %s' % bus
    assert isinstance(dbus_props, dict), 'dbus_props is not dict type: %s' % dbus_props
    try:
        interface = bus.get_object(dbus_props['service'], dbus_props['objectPath'])
        proxy = interface.get_dbus_method(dbus_props['methodUnSet'], dbus_props['interface'])
        proxy(cookie)
        logger.info('Release inhibit Suspend')
        return None
    except dbus.exceptions.DBusException:
        logger.warning('Release inhibit Suspend failed.')
        return (cookie, bus, dbus_props)

def getSshKeyFingerprint(path):
    '''return the hex fingerprint of a given ssh key
    '''
    if not os.path.exists(path):
        return
    cmd = ['ssh-keygen', '-l', '-f', path]
    proc = subprocess.Popen(cmd, stdout = subprocess.PIPE, stderr = open(os.devnull, 'w'))
    output = proc.communicate()[0]
    m = re.match(b'\d+\s+([a-zA-Z0-9:]+).*', output)
    if m:
        return m.group(1).decode('UTF-8')

def readCrontab():
    '''read a list of lines from users crontab
    '''
    cmd = ['crontab', '-l']
    if not check_command(cmd[0]):
        logger.debug('crontab not found.')
        return []
    else:
        proc = subprocess.Popen(cmd,
                                stdout = subprocess.PIPE,
                                stderr = subprocess.PIPE,
                                universal_newlines = True)
        out, err = proc.communicate()
        if proc.returncode or err:
            logger.error('Failed to get crontab lines: %s, %s'
                         %(proc.returncode, err))
            return []
        else:
            crontab = [x.strip() for x in out.strip('\n').split('\n')]
            logger.debug('Read %s lines from users crontab'
                         %len(crontab))
            return crontab

def writeCrontab(lines):
    '''write a list of lines to users crontab
    '''
    assert isinstance(lines, (list, tuple)), 'lines is not list or tuple type: %s' % lines
    with tempfile.NamedTemporaryFile(mode = 'wt') as f:
        f.write('\n'.join(lines))
        f.write('\n\n')
        f.flush()
        cmd = ['crontab', f.name]
        proc = subprocess.Popen(cmd,
                                stdout = subprocess.DEVNULL,
                                stderr = subprocess.PIPE,
                                universal_newlines = True)
        out, err = proc.communicate()
    if proc.returncode or err:
        logger.error('Failed to write lines to crontab: %s, %s'
                     %(proc.returncode, err))
        return False
    else:
        logger.debug('Wrote %s lines to users crontab'
                     %len(lines))
        return True

def splitCommands(cmds, head = '', tail = '', maxLength = 0, additionalChars = 0):
    while cmds:
        s = head
        while cmds and ((len(s + cmds[0] + tail) + additionalChars <= maxLength) or not maxLength):
            s += cmds.pop(0)
        s += tail
        yield s

def fdDup(old, new_fd, mode = 'w'):
    """
    Duplicate file descriptor `old` to `new_fd` and closing the latter first.
    Used to redirect stdin, stdout and stderr from daemonized threads.

    Args:
        old (str):                  Path to the old file (e.g. /dev/stdout)
        new_fd (_io.TextIOWrapper): file object for the new file
        mode (str):                 mode in which the old file should be opened
    """
    try:
        fd = open(old, mode)
        os.dup2(fd.fileno(), new_fd.fileno())
    except OSError as e:
        logger.debug('Failed to redirect {}: {}'.format(old, str(e)))

class UniquenessSet:
    '''a class to check for uniqueness of snapshots of the same [item]'''
    def __init__(self, dc = False, follow_symlink = False, list_equal_to = False):
        self.deep_check = dc
        self.follow_sym = follow_symlink
        self._uniq_dict = {}      # if not self._uniq_dict[size] -> size already checked with md5sum
        self._size_inode = set()  # if (size,inode) in self._size_inode -> path is a hlink
        self.list_equal_to = list_equal_to
        if list_equal_to:
            st = os.stat(list_equal_to)
            if self.deep_check:
                self.reference = (st.st_size, _get_md5sum_from_path(list_equal_to))
            else:
                self.reference = (st.st_size, int(st.st_mtime))

    def check_for(self, input_path):
        # follow symlinks ?
        path = input_path
        if self.follow_sym and os.path.islink(input_path):
            path = os.readlink(input_path)

        if self.list_equal_to:
            return self.check_equal(path)
        else:
            return self.check_unique(path)

    def check_unique(self, path):
        '''store a unique key for path, return True if path is unique'''
        # check
        if self.deep_check:
            dum = os.stat(path)
            size,inode  = dum.st_size, dum.st_ino
            # is it a hlink ?
            if (size, inode) in self._size_inode:
                logger.debug("[deep test] : skip, it's a duplicate (size, inode)", self)
                return False
            self._size_inode.add( (size,inode) )
            if size not in list(self._uniq_dict.keys()):
                # first item of that size
                unique_key = size
                logger.debug("[deep test] : store current size ?", self)
            else:
                prev = self._uniq_dict[size]
                if prev:
                    # store md5sum instead of previously stored size
                    md5sum_prev = _get_md5sum_from_path(prev)
                    self._uniq_dict[size] = None
                    self._uniq_dict[md5sum_prev] = prev
                    logger.debug("[deep test] : size duplicate, remove the size, store prev md5sum", self)
                unique_key = _get_md5sum_from_path(path)
                logger.debug("[deep test] : store current md5sum ?", self)
        else:
            # store a tuple of (size, modification time)
            obj  = os.stat(path)
            unique_key = (obj.st_size, int(obj.st_mtime))
        # store if not already present, then return True
        if unique_key not in list(self._uniq_dict.keys()):
            logger.debug(" >> ok, store !", self)
            self._uniq_dict[unique_key] = path
            return True
        logger.debug(" >> skip (it's a duplicate)", self)
        return False

    def check_equal(self, path):
        '''return True if path and reference are equal'''
        st = os.stat(path)
        if self.deep_check:
            if self.reference[0] == st.st_size:
                return self.reference[1] == _get_md5sum_from_path(path)
            return False
        else:
            return self.reference == (st.st_size, int(st.st_mtime))

class Alarm(object):
    """
    Timeout for FIFO. This does not work with threading.
    """
    def __init__(self, callback = None):
        self.callback = callback

    def start(self, timeout):
        """
        start timer
        """
        try:
            signal.signal(signal.SIGALRM, self.handler)
            signal.alarm(timeout)
        except ValueError:
            pass

    def stop(self):
        """
        stop timer before it come to an end
        """
        try:
            signal.alarm(0)
        except:
            pass

    def handler(self, signum, frame):
        """
        timeout occur.
        """
        if self.callback is None:
            raise Timeout()
        else:
            self.callback()

class ShutDown(object):
    """Shutdown the system after the current snapshot has finished.
    This should work for KDE, Gnome, Unity, Cinnamon, XFCE, Mate and E17.
    """
    DBUS_SHUTDOWN ={'gnome':   {'bus':          'sessionbus',
                                'service':      'org.gnome.SessionManager',
                                'objectPath':   '/org/gnome/SessionManager',
                                'method':       'Shutdown',
                                    #methods    Shutdown
                                    #           Reboot
                                    #           Logout
                                'interface':    'org.gnome.SessionManager',
                                'arguments':    ()
                                    #arg (only with Logout)
                                    #           0 normal
                                    #           1 no confirm
                                    #           2 force
                               },
                    'kde':     {'bus':          'sessionbus',
                                'service':      'org.kde.ksmserver',
                                'objectPath':   '/KSMServer',
                                'method':       'logout',
                                'interface':    'org.kde.KSMServerInterface',
                                'arguments':    (-1, 2, -1)
                                    #1st arg   -1 confirm
                                    #           0 no confirm
                                    #2nd arg   -1 full dialog with default logout
                                    #           0 logout
                                    #           1 restart
                                    #           2 shutdown
                                    #3rd arg   -1 wait 30sec
                                    #           2 immediately
                               },
                    'xfce':    {'bus':          'sessionbus',
                                'service':      'org.xfce.SessionManager',
                                'objectPath':   '/org/xfce/SessionManager',
                                'method':       'Shutdown',
                                    #methods    Shutdown
                                    #           Restart
                                    #           Suspend (no args)
                                    #           Hibernate (no args)
                                    #           Logout (two args)
                                'interface':    'org.xfce.Session.Manager',
                                'arguments':    (True,)
                                    #arg        True    allow saving
                                    #           False   don't allow saving
                                    #1nd arg (only with Logout)
                                    #           True    show dialog
                                    #           False   don't show dialog
                                    #2nd arg (only with Logout)
                                    #           True    allow saving
                                    #           False   don't allow saving
                               },
                    'mate':    {'bus':          'sessionbus',
                                'service':      'org.mate.SessionManager',
                                'objectPath':   '/org/mate/SessionManager',
                                'method':       'Shutdown',
                                    #methods    Shutdown
                                    #           Logout
                                'interface':    'org.mate.SessionManager',
                                'arguments':    ()
                                    #arg (only with Logout)
                                    #           0 normal
                                    #           1 no confirm
                                    #           2 force
                               },
                    'e17':     {'bus':          'sessionbus',
                                'service':      'org.enlightenment.Remote.service',
                                'objectPath':   '/org/enlightenment/Remote/RemoteObject',
                                'method':       'Halt',
                                    #methods    Halt -> Shutdown
                                    #           Reboot
                                    #           Logout
                                    #           Suspend
                                    #           Hibernate
                                'interface':    'org.enlightenment.Remote.Core',
                                'arguments':    ()
                               },
                    'e19':     {'bus':          'sessionbus',
                                'service':      'org.enlightenment.wm.service',
                                'objectPath':   '/org/enlightenment/wm/RemoteObject',
                                'method':       'Shutdown',
                                    #methods    Shutdown
                                    #           Restart
                                'interface':    'org.enlightenment.wm.Core',
                                'arguments':    ()
                               },
                    'z_freed': {'bus':          'systembus',
                                'service':      'org.freedesktop.login1',
                                'objectPath':   '/org/freedesktop/login1',
                                'method':       'PowerOff',
                                'interface':    'org.freedesktop.login1.Manager',
                                'arguments':    (True, )
                               }
                   }

    def __init__(self):
        self.is_root = isRoot()
        if self.is_root:
            self.proxy, self.args = None, None
        else:
            self.proxy, self.args = self._prepair()
        self.activate_shutdown = False
        self.started = False

    def _prepair(self):
        """try to connect to the given dbus services. If successful it will
        return a callable dbus proxy and those arguments.
        """
        try:
            if 'DBUS_SESSION_BUS_ADDRESS' in os.environ:
                sessionbus = dbus.bus.BusConnection(os.environ['DBUS_SESSION_BUS_ADDRESS'])
            else:
                sessionbus = dbus.SessionBus()
            systembus  = dbus.SystemBus()
        except:
            return( (None, None) )
        des = list(self.DBUS_SHUTDOWN.keys())
        des.sort()
        for de in des:
            if de == 'gnome' and self.unity_7():
                continue
            dbus_props = self.DBUS_SHUTDOWN[de]
            try:
                if dbus_props['bus'] == 'sessionbus':
                    bus = sessionbus
                else:
                    bus = systembus
                interface = bus.get_object(dbus_props['service'], dbus_props['objectPath'])
                proxy = interface.get_dbus_method(dbus_props['method'], dbus_props['interface'])
                return( (proxy, dbus_props['arguments']) )
            except dbus.exceptions.DBusException:
                continue
        return( (None, None) )

    def can_shutdown(self):
        """indicate if a valid dbus service is available to shutdown system.
        """
        return(not self.proxy is None or self.is_root)

    def ask_before_quit(self):
        """indicate if ShutDown is ready to fire and so the application
        shouldn't be closed.
        """
        return(self.activate_shutdown and not self.started)

    def shutdown(self):
        """run 'shutdown -h now' if we are root or
        call the dbus proxy to start the shutdown.
        """
        if not self.activate_shutdown:
            return(False)
        if self.is_root:
            syncfs()
            self.started = True
            proc = subprocess.Popen(['shutdown', '-h', 'now'])
            proc.communicate()
            return proc.returncode
        if self.proxy is None:
            return(False)
        else:
            syncfs()
            self.started = True
            return(self.proxy(*self.args))

    def unity_7(self):
        """Unity >= 7.0 doesn't shutdown automatically. It will
        only show shutdown dialog and wait for user input.
        """
        if not check_command('unity'):
            return False
        unity_version = read_command_output('unity --version')
        m = re.match(r'unity ([\d\.]+)', unity_version)
        return m and StrictVersion(m.group(1)) >= StrictVersion('7.0') and process_exists('unity-panel-service')

class SetupUdev(object):
    """Setup Udev rules for starting BackInTime when a drive get connected.
    This is done by serviceHelper.py script (included in backintime-qt4)
    running as root though DBus.
    """
    CONNECTION = 'net.launchpad.backintime.serviceHelper'
    OBJECT = '/UdevRules'
    INTERFACE = 'net.launchpad.backintime.serviceHelper.UdevRules'
    MEMBERS = ('addRule', 'save', 'delete')
    def __init__(self):
        if dbus is None:
            self.isReady = False
            return
        try:
            bus = dbus.SystemBus()
            conn = bus.get_object(SetupUdev.CONNECTION, SetupUdev.OBJECT)
            self.iface = dbus.Interface(conn, SetupUdev.INTERFACE)
        except dbus.exceptions.DBusException as e:
            if e._dbus_error_name in ('org.freedesktop.DBus.Error.NameHasNoOwner',
                                      'org.freedesktop.DBus.Error.ServiceUnknown',
                                      'org.freedesktop.DBus.Error.FileNotFound'):
                conn = None
            else:
                raise
        self.isReady = bool(conn)

    def addRule(self, cmd, uuid):
        """prepair rules in serviceHelper.py
        """
        if not self.isReady:
            return
        try:
            return self.iface.addRule(cmd, uuid)
        except dbus.exceptions.DBusException as e:
            if e._dbus_error_name == 'net.launchpad.backintime.InvalidChar':
                raise InvalidChar(str(e))
            else:
                raise

    def save(self):
        """save rules with serviceHelper.py after authentication
        If no rules where added before this will delete current rule.
        """
        if not self.isReady:
            return
        try:
            return self.iface.save()
        except dbus.exceptions.DBusException as e:
            if e._dbus_error_name == 'com.ubuntu.DeviceDriver.PermissionDeniedByPolicy':
                raise PermissionDeniedByPolicy(str(e))
            else:
                raise

    def clean(self):
        """clean up remote cache
        """
        if not self.isReady:
            return
        self.iface.clean()

class PathHistory(object):
    def __init__(self, path):
        self.history = [path,]
        self.index = 0

    def append(self, path):
        #append path after the current index
        self.history = self.history[:self.index + 1] + [path,]
        self.index = len(self.history) - 1

    def previous(self):
        if self.index == 0:
            return self.history[0]
        try:
            path = self.history[self.index - 1]
        except IndexError:
            return self.history[self.index]
        self.index -= 1
        return path

    def next(self):
        if self.index == len(self.history) - 1:
            return self.history[-1]
        try:
            path = self.history[self.index + 1]
        except IndexError:
            return self.history[self.index]
        self.index += 1
        return path

    def reset(self, path):
        self.history = [path,]
        self.index = 0

class Daemon:
    """
    A generic daemon class.

    Usage: subclass the Daemon class and override the run() method

    Daemon Copyright by Sander Marechal
    License CC BY-SA 3.0
    http://www.jejik.com/articles/2007/02/a_simple_unix_linux_daemon_in_python/
    """
    def __init__(self, pidfile = None, stdin='/dev/null', stdout='/dev/stdout', stderr='/dev/null'):
        self.stdin = stdin
        self.stdout = stdout
        self.stderr = stderr
        self.pidfile = pidfile
        if pidfile:
            self.appInstance = ApplicationInstance(pidfile, auto_exit = False, flock = False)

    def daemonize(self):
        """
        do the UNIX double-fork magic, see Stevens' "Advanced
        Programming in the UNIX Environment" for details (ISBN 0201563177)
        http://www.erlenstar.demon.co.uk/unix/faq_2.html#SEC16
        """
        try:
            pid = os.fork()
            logger.debug('first fork pid: {}'.format(pid), self)
            if pid > 0:
                # exit first parent
                sys.exit(0)
        except OSError as e:
            logger.error("fork #1 failed: %d (%s)" % (e.errno, str(e)), self)
            sys.exit(1)

        # decouple from parent environment
        logger.debug('decouple from parent environment', self)
        os.chdir("/")
        os.setsid()
        os.umask(0)

        # do second fork
        try:
            pid = os.fork()
            logger.debug('second fork pid: {}'.format(pid), self)
            if pid > 0:
                # exit from second parent
                sys.exit(0)
        except OSError as e:
            logger.error("fork #2 failed: %d (%s)" % (e.errno, str(e)), self)
            sys.exit(1)

        # redirect standard file descriptors
        logger.debug('redirect standard file descriptors', self)

        sys.stdout.flush()
        sys.stderr.flush()
        fdDup(self.stdin, sys.stdin, 'r')
        fdDup(self.stdout, sys.stdout, 'w')
        fdDup(self.stderr, sys.stderr, 'w')

        signal.signal(signal.SIGTERM, self.cleanupHandler)
        if self.pidfile:
            atexit.register(self.appInstance.exit_application)
            # write pidfile
            logger.debug('write pidfile', self)
            self.appInstance.start_application()

    def cleanupHandler(self, signum, frame):
        if self.pidfile:
            self.appInstance.exit_application()
        sys.exit(0)

    def start(self):
        """
        Start the daemon
        """
        # Check for a pidfile to see if the daemon already runs
        if self.pidfile and not self.appInstance.check():
            message = "pidfile %s already exist. Daemon already running?\n"
            logger.error(message % self.pidfile, self)
            sys.exit(1)

        # Start the daemon
        self.daemonize()
        self.run()

    def stop(self):
        """
        Stop the daemon
        """
        if not self.pidfile:
            logger.debug("Unattended daemon can't be stopped. No PID file", self)
            return

        # Get the pid from the pidfile
        pid, procname = self.appInstance.readPidFile()

        if not pid:
            message = "pidfile %s does not exist. Daemon not running?\n"
            logger.error(message % self.pidfile, self)
            return # not an error in a restart

        # Try killing the daemon process
        try:
            while True:
                os.kill(pid, signal.SIGTERM)
                sleep(0.1)
        except OSError as err:
            if err.errno == errno.ESRCH:
                #no such process
                self.appInstance.exit_application()
            else:
                logger.error(str(err), self)
                sys.exit(1)

    def restart(self):
        """
        Restart the daemon
        """
        self.stop()
        self.start()

    def reload(self):
        """
        send SIGHUP signal to process
        """
        if not self.pidfile:
            logger.debug("Unattended daemon can't be reloaded. No PID file", self)
            return

        # Get the pid from the pidfile
        pid, procname = self.appInstance.readPidFile()

        if not pid:
            message = "pidfile %s does not exist. Daemon not running?\n"
            logger.error(message % self.pidfile, self)
            return

        # Try killing the daemon process
        try:
            os.kill(pid, signal.SIGHUP)
        except OSError as err:
            if err.errno == errno.ESRCH:
                #no such process
                self.appInstance.exit_application()
            else:
                sys.stderr.write(str(err))
                sys.exit(1)

    def status(self):
        """
        return status
        """
        if not self.pidfile:
            logger.debug("Unattended daemon can't be checked. No PID file", self)
            return
        return not self.appInstance.check()

    def run(self):
        """
        You should override this method when you subclass Daemon. It will be called after the process has been
        daemonized by start() or restart().
        """
        pass

def __log_keyring_warning():
    from time import sleep
    sleep(0.1)
    logger.warning('import keyring failed')

if keyring is None and keyring_warn:
    #delay warning to give logger some time to import
    import _thread
    _thread.start_new_thread(__log_keyring_warning, ())
    # logger.warning('import keyring failed')
