# Copyright (C) 2013 Canonical Ltd.
#
# Author: Scott Moser <scott.moser@canonical.com>
#
# This file is part of cloud-init. See LICENSE file for license information.

import base64
import contextlib
import crypt
from functools import partial
import os
import os.path
import re
from time import time
from xml.dom import minidom
import xml.etree.ElementTree as ET

from cloudinit import log as logging
from cloudinit import net
from cloudinit.net.dhcp import EphemeralDHCPv4
from cloudinit import sources
from cloudinit.sources.helpers.azure import get_metadata_from_fabric
from cloudinit.url_helper import readurl, UrlError
from cloudinit import util

LOG = logging.getLogger(__name__)

DS_NAME = 'Azure'
DEFAULT_METADATA = {"instance-id": "iid-AZURE-NODE"}
AGENT_START = ['service', 'walinuxagent', 'start']
AGENT_START_BUILTIN = "__builtin__"
BOUNCE_COMMAND_IFUP = [
    'sh', '-xc',
    "i=$interface; x=0; ifdown $i || x=$?; ifup $i || x=$?; exit $x"
]
BOUNCE_COMMAND_FREEBSD = [
    'sh', '-xc',
    ("i=$interface; x=0; ifconfig down $i || x=$?; "
     "ifconfig up $i || x=$?; exit $x")
]

# azure systems will always have a resource disk, and 66-azure-ephemeral.rules
# ensures that it gets linked to this path.
RESOURCE_DISK_PATH = '/dev/disk/cloud/azure_resource'
DEFAULT_PRIMARY_NIC = 'eth0'
LEASE_FILE = '/var/lib/dhcp/dhclient.eth0.leases'
DEFAULT_FS = 'ext4'
# DMI chassis-asset-tag is set static for all azure instances
AZURE_CHASSIS_ASSET_TAG = '7783-7084-3265-9085-8269-3286-77'
REPROVISION_MARKER_FILE = "/var/lib/cloud/data/poll_imds"
REPORTED_READY_MARKER_FILE = "/var/lib/cloud/data/reported_ready"
IMDS_URL = "http://169.254.169.254/metadata/reprovisiondata"


def find_storvscid_from_sysctl_pnpinfo(sysctl_out, deviceid):
    # extract the 'X' from dev.storvsc.X. if deviceid matches
    """
    dev.storvsc.1.%pnpinfo:
        classid=32412632-86cb-44a2-9b5c-50d1417354f5
        deviceid=00000000-0001-8899-0000-000000000000
    """
    for line in sysctl_out.splitlines():
        if re.search(r"pnpinfo", line):
            fields = line.split()
            if len(fields) >= 3:
                columns = fields[2].split('=')
                if (len(columns) >= 2 and
                        columns[0] == "deviceid" and
                        columns[1].startswith(deviceid)):
                    comps = fields[0].split('.')
                    return comps[2]
    return None


def find_busdev_from_disk(camcontrol_out, disk_drv):
    # find the scbusX from 'camcontrol devlist -b' output
    # if disk_drv matches the specified disk driver, i.e. blkvsc1
    """
    scbus0 on ata0 bus 0
    scbus1 on ata1 bus 0
    scbus2 on blkvsc0 bus 0
    scbus3 on blkvsc1 bus 0
    scbus4 on storvsc2 bus 0
    scbus5 on storvsc3 bus 0
    scbus-1 on xpt0 bus 0
    """
    for line in camcontrol_out.splitlines():
        if re.search(disk_drv, line):
            items = line.split()
            return items[0]
    return None


def find_dev_from_busdev(camcontrol_out, busdev):
    # find the daX from 'camcontrol devlist' output
    # if busdev matches the specified value, i.e. 'scbus2'
    """
    <Msft Virtual CD/ROM 1.0>          at scbus1 target 0 lun 0 (cd0,pass0)
    <Msft Virtual Disk 1.0>            at scbus2 target 0 lun 0 (da0,pass1)
    <Msft Virtual Disk 1.0>            at scbus3 target 1 lun 0 (da1,pass2)
    """
    for line in camcontrol_out.splitlines():
        if re.search(busdev, line):
            items = line.split('(')
            if len(items) == 2:
                dev_pass = items[1].split(',')
                return dev_pass[0]
    return None


def execute_or_debug(cmd, fail_ret=None):
    try:
        return util.subp(cmd)[0]
    except util.ProcessExecutionError:
        LOG.debug("Failed to execute: %s", ' '.join(cmd))
        return fail_ret


def get_dev_storvsc_sysctl():
    return execute_or_debug(["sysctl", "dev.storvsc"], fail_ret="")


def get_camcontrol_dev_bus():
    return execute_or_debug(['camcontrol', 'devlist', '-b'])


def get_camcontrol_dev():
    return execute_or_debug(['camcontrol', 'devlist'])


def get_resource_disk_on_freebsd(port_id):
    g0 = "00000000"
    if port_id > 1:
        g0 = "00000001"
        port_id = port_id - 2
    g1 = "000" + str(port_id)
    g0g1 = "{0}-{1}".format(g0, g1)
    """
    search 'X' from
       'dev.storvsc.X.%pnpinfo:
           classid=32412632-86cb-44a2-9b5c-50d1417354f5
           deviceid=00000000-0001-8899-0000-000000000000'
    """
    sysctl_out = get_dev_storvsc_sysctl()

    storvscid = find_storvscid_from_sysctl_pnpinfo(sysctl_out, g0g1)
    if not storvscid:
        LOG.debug("Fail to find storvsc id from sysctl")
        return None

    camcontrol_b_out = get_camcontrol_dev_bus()
    camcontrol_out = get_camcontrol_dev()
    # try to find /dev/XX from 'blkvsc' device
    blkvsc = "blkvsc{0}".format(storvscid)
    scbusx = find_busdev_from_disk(camcontrol_b_out, blkvsc)
    if scbusx:
        devname = find_dev_from_busdev(camcontrol_out, scbusx)
        if devname is None:
            LOG.debug("Fail to find /dev/daX")
            return None
        return devname
    # try to find /dev/XX from 'storvsc' device
    storvsc = "storvsc{0}".format(storvscid)
    scbusx = find_busdev_from_disk(camcontrol_b_out, storvsc)
    if scbusx:
        devname = find_dev_from_busdev(camcontrol_out, scbusx)
        if devname is None:
            LOG.debug("Fail to find /dev/daX")
            return None
        return devname
    return None


# update the FreeBSD specific information
if util.is_FreeBSD():
    DEFAULT_PRIMARY_NIC = 'hn0'
    LEASE_FILE = '/var/db/dhclient.leases.hn0'
    DEFAULT_FS = 'freebsd-ufs'
    res_disk = get_resource_disk_on_freebsd(1)
    if res_disk is not None:
        LOG.debug("resource disk is not None")
        RESOURCE_DISK_PATH = "/dev/" + res_disk
    else:
        LOG.debug("resource disk is None")

BUILTIN_DS_CONFIG = {
    'agent_command': AGENT_START_BUILTIN,
    'data_dir': "/var/lib/waagent",
    'set_hostname': True,
    'hostname_bounce': {
        'interface': DEFAULT_PRIMARY_NIC,
        'policy': True,
        'command': 'builtin',
        'hostname_command': 'hostname',
    },
    'disk_aliases': {'ephemeral0': RESOURCE_DISK_PATH},
    'dhclient_lease_file': LEASE_FILE,
}

BUILTIN_CLOUD_CONFIG = {
    'disk_setup': {
        'ephemeral0': {'table_type': 'gpt',
                       'layout': [100],
                       'overwrite': True},
    },
    'fs_setup': [{'filesystem': DEFAULT_FS,
                  'device': 'ephemeral0.1'}],
}

DS_CFG_PATH = ['datasource', DS_NAME]
DS_CFG_KEY_PRESERVE_NTFS = 'never_destroy_ntfs'
DEF_EPHEMERAL_LABEL = 'Temporary Storage'

# The redacted password fails to meet password complexity requirements
# so we can safely use this to mask/redact the password in the ovf-env.xml
DEF_PASSWD_REDACTION = 'REDACTED'


def get_hostname(hostname_command='hostname'):
    if not isinstance(hostname_command, (list, tuple)):
        hostname_command = (hostname_command,)
    return util.subp(hostname_command, capture=True)[0].strip()


def set_hostname(hostname, hostname_command='hostname'):
    util.subp([hostname_command, hostname])


@contextlib.contextmanager
def temporary_hostname(temp_hostname, cfg, hostname_command='hostname'):
    """
    Set a temporary hostname, restoring the previous hostname on exit.

    Will have the value of the previous hostname when used as a context
    manager, or None if the hostname was not changed.
    """
    policy = cfg['hostname_bounce']['policy']
    previous_hostname = get_hostname(hostname_command)
    if (not util.is_true(cfg.get('set_hostname')) or
       util.is_false(policy) or
       (previous_hostname == temp_hostname and policy != 'force')):
        yield None
        return
    set_hostname(temp_hostname, hostname_command)
    try:
        yield previous_hostname
    finally:
        set_hostname(previous_hostname, hostname_command)


class DataSourceAzure(sources.DataSource):

    dsname = 'Azure'
    _negotiated = False

    def __init__(self, sys_cfg, distro, paths):
        sources.DataSource.__init__(self, sys_cfg, distro, paths)
        self.seed_dir = os.path.join(paths.seed_dir, 'azure')
        self.cfg = {}
        self.seed = None
        self.ds_cfg = util.mergemanydict([
            util.get_cfg_by_path(sys_cfg, DS_CFG_PATH, {}),
            BUILTIN_DS_CONFIG])
        self.dhclient_lease_file = self.ds_cfg.get('dhclient_lease_file')
        self._network_config = None

    def __str__(self):
        root = sources.DataSource.__str__(self)
        return "%s [seed=%s]" % (root, self.seed)

    def bounce_network_with_azure_hostname(self):
        # When using cloud-init to provision, we have to set the hostname from
        # the metadata and "bounce" the network to force DDNS to update via
        # dhclient
        azure_hostname = self.metadata.get('local-hostname')
        LOG.debug("Hostname in metadata is %s", azure_hostname)
        hostname_command = self.ds_cfg['hostname_bounce']['hostname_command']

        with temporary_hostname(azure_hostname, self.ds_cfg,
                                hostname_command=hostname_command) \
                as previous_hn:
            if (previous_hn is not None and
                    util.is_true(self.ds_cfg.get('set_hostname'))):
                cfg = self.ds_cfg['hostname_bounce']

                # "Bouncing" the network
                try:
                    return perform_hostname_bounce(hostname=azure_hostname,
                                                   cfg=cfg,
                                                   prev_hostname=previous_hn)
                except Exception as e:
                    LOG.warning("Failed publishing hostname: %s", e)
                    util.logexc(LOG, "handling set_hostname failed")
        return False

    def get_metadata_from_agent(self):
        temp_hostname = self.metadata.get('local-hostname')
        agent_cmd = self.ds_cfg['agent_command']
        LOG.debug("Getting metadata via agent.  hostname=%s cmd=%s",
                  temp_hostname, agent_cmd)

        self.bounce_network_with_azure_hostname()

        try:
            invoke_agent(agent_cmd)
        except util.ProcessExecutionError:
            # claim the datasource even if the command failed
            util.logexc(LOG, "agent command '%s' failed.",
                        self.ds_cfg['agent_command'])

        ddir = self.ds_cfg['data_dir']

        fp_files = []
        key_value = None
        for pk in self.cfg.get('_pubkeys', []):
            if pk.get('value', None):
                key_value = pk['value']
                LOG.debug("ssh authentication: using value from fabric")
            else:
                bname = str(pk['fingerprint'] + ".crt")
                fp_files += [os.path.join(ddir, bname)]
                LOG.debug("ssh authentication: "
                          "using fingerprint from fabirc")

        # wait very long for public SSH keys to arrive
        # https://bugs.launchpad.net/cloud-init/+bug/1717611
        missing = util.log_time(logfunc=LOG.debug,
                                msg="waiting for SSH public key files",
                                func=util.wait_for_files,
                                args=(fp_files, 900))

        if len(missing):
            LOG.warning("Did not find files, but going on: %s", missing)

        metadata = {}
        metadata['public-keys'] = key_value or pubkeys_from_crt_files(fp_files)
        return metadata

    def _get_data(self):
        # azure removes/ejects the cdrom containing the ovf-env.xml
        # file on reboot.  So, in order to successfully reboot we
        # need to look in the datadir and consider that valid
        asset_tag = util.read_dmi_data('chassis-asset-tag')
        if asset_tag != AZURE_CHASSIS_ASSET_TAG:
            LOG.debug("Non-Azure DMI asset tag '%s' discovered.", asset_tag)
            return False

        ddir = self.ds_cfg['data_dir']

        candidates = [self.seed_dir]
        if os.path.isfile(REPROVISION_MARKER_FILE):
            candidates.insert(0, "IMDS")
        candidates.extend(list_possible_azure_ds_devs())
        if ddir:
            candidates.append(ddir)

        found = None
        reprovision = False
        for cdev in candidates:
            try:
                if cdev == "IMDS":
                    ret = None
                    reprovision = True
                elif cdev.startswith("/dev/"):
                    if util.is_FreeBSD():
                        ret = util.mount_cb(cdev, load_azure_ds_dir,
                                            mtype="udf", sync=False)
                    else:
                        ret = util.mount_cb(cdev, load_azure_ds_dir)
                else:
                    ret = load_azure_ds_dir(cdev)

            except NonAzureDataSource:
                continue
            except BrokenAzureDataSource as exc:
                raise exc
            except util.MountFailedError:
                LOG.warning("%s was not mountable", cdev)
                continue

            if reprovision or self._should_reprovision(ret):
                ret = self._reprovision()
            (md, self.userdata_raw, cfg, files) = ret
            self.seed = cdev
            self.metadata = util.mergemanydict([md, DEFAULT_METADATA])
            self.cfg = util.mergemanydict([cfg, BUILTIN_CLOUD_CONFIG])
            found = cdev

            LOG.debug("found datasource in %s", cdev)
            break

        if not found:
            return False

        if found == ddir:
            LOG.debug("using files cached in %s", ddir)

        seed = _get_random_seed()
        if seed:
            self.metadata['random_seed'] = seed

        user_ds_cfg = util.get_cfg_by_path(self.cfg, DS_CFG_PATH, {})
        self.ds_cfg = util.mergemanydict([user_ds_cfg, self.ds_cfg])

        # walinux agent writes files world readable, but expects
        # the directory to be protected.
        write_files(ddir, files, dirmode=0o700)

        self.metadata['instance-id'] = util.read_dmi_data('system-uuid')

        return True

    def device_name_to_device(self, name):
        return self.ds_cfg['disk_aliases'].get(name)

    def get_config_obj(self):
        return self.cfg

    def check_instance_id(self, sys_cfg):
        # quickly (local check only) if self.instance_id is still valid
        return sources.instance_id_matches_system_uuid(self.get_instance_id())

    def setup(self, is_new_instance):
        if self._negotiated is False:
            LOG.debug("negotiating for %s (new_instance=%s)",
                      self.get_instance_id(), is_new_instance)
            fabric_data = self._negotiate()
            LOG.debug("negotiating returned %s", fabric_data)
            if fabric_data:
                self.metadata.update(fabric_data)
            self._negotiated = True
        else:
            LOG.debug("negotiating already done for %s",
                      self.get_instance_id())

    def _poll_imds(self):
        """Poll IMDS for the new provisioning data until we get a valid
        response. Then return the returned JSON object."""
        url = IMDS_URL + "?api-version=2017-04-02"
        headers = {"Metadata": "true"}
        report_ready = bool(not os.path.isfile(REPORTED_READY_MARKER_FILE))
        LOG.debug("Start polling IMDS")

        def exc_cb(msg, exception):
            if isinstance(exception, UrlError) and exception.code == 404:
                return True
            # If we get an exception while trying to call IMDS, we
            # call DHCP and setup the ephemeral network to acquire the new IP.
            return False

        while True:
            try:
                with EphemeralDHCPv4() as lease:
                    if report_ready:
                        path = REPORTED_READY_MARKER_FILE
                        LOG.info(
                            "Creating a marker file to report ready: %s", path)
                        util.write_file(path, "{pid}: {time}\n".format(
                            pid=os.getpid(), time=time()))
                        self._report_ready(lease=lease)
                        report_ready = False
                    return readurl(url, timeout=1, headers=headers,
                                   exception_cb=exc_cb, infinite=True).contents
            except UrlError:
                pass

    def _report_ready(self, lease):
        """Tells the fabric provisioning has completed
           before we go into our polling loop."""
        try:
            get_metadata_from_fabric(None, lease['unknown-245'])
        except Exception:
            LOG.warning(
                "Error communicating with Azure fabric; You may experience."
                "connectivity issues.", exc_info=True)

    def _should_reprovision(self, ret):
        """Whether or not we should poll IMDS for reprovisioning data.
        Also sets a marker file to poll IMDS.

        The marker file is used for the following scenario: the VM boots into
        this polling loop, which we expect to be proceeding infinitely until
        the VM is picked. If for whatever reason the platform moves us to a
        new host (for instance a hardware issue), we need to keep polling.
        However, since the VM reports ready to the Fabric, we will not attach
        the ISO, thus cloud-init needs to have a way of knowing that it should
        jump back into the polling loop in order to retrieve the ovf_env."""
        if not ret:
            return False
        (_md, self.userdata_raw, cfg, _files) = ret
        path = REPROVISION_MARKER_FILE
        if (cfg.get('PreprovisionedVm') is True or
                os.path.isfile(path)):
            if not os.path.isfile(path):
                LOG.info("Creating a marker file to poll imds: %s",
                         path)
                util.write_file(path, "{pid}: {time}\n".format(
                    pid=os.getpid(), time=time()))
            return True
        return False

    def _reprovision(self):
        """Initiate the reprovisioning workflow."""
        contents = self._poll_imds()
        md, ud, cfg = read_azure_ovf(contents)
        return (md, ud, cfg, {'ovf-env.xml': contents})

    def _negotiate(self):
        """Negotiate with fabric and return data from it.

           On success, returns a dictionary including 'public_keys'.
           On failure, returns False.
        """

        if self.ds_cfg['agent_command'] == AGENT_START_BUILTIN:
            self.bounce_network_with_azure_hostname()

            metadata_func = partial(get_metadata_from_fabric,
                                    fallback_lease_file=self.
                                    dhclient_lease_file)
        else:
            metadata_func = self.get_metadata_from_agent

        LOG.debug("negotiating with fabric via agent command %s",
                  self.ds_cfg['agent_command'])
        try:
            fabric_data = metadata_func()
        except Exception:
            LOG.warning(
                "Error communicating with Azure fabric; You may experience."
                "connectivity issues.", exc_info=True)
            return False
        util.del_file(REPORTED_READY_MARKER_FILE)
        util.del_file(REPROVISION_MARKER_FILE)
        return fabric_data

    def activate(self, cfg, is_new_instance):
        address_ephemeral_resize(is_new_instance=is_new_instance,
                                 preserve_ntfs=self.ds_cfg.get(
                                     DS_CFG_KEY_PRESERVE_NTFS, False))
        return

    @property
    def network_config(self):
        """Generate a network config like net.generate_fallback_network() with
           the following execptions.

           1. Probe the drivers of the net-devices present and inject them in
              the network configuration under params: driver: <driver> value
           2. Generate a fallback network config that does not include any of
              the blacklisted devices.
        """
        blacklist = ['mlx4_core']
        if not self._network_config:
            LOG.debug('Azure: generating fallback configuration')
            # generate a network config, blacklist picking any mlx4_core devs
            netconfig = net.generate_fallback_config(
                blacklist_drivers=blacklist, config_driver=True)

            self._network_config = netconfig

        return self._network_config


def _partitions_on_device(devpath, maxnum=16):
    # return a list of tuples (ptnum, path) for each part on devpath
    for suff in ("-part", "p", ""):
        found = []
        for pnum in range(1, maxnum):
            ppath = devpath + suff + str(pnum)
            if os.path.exists(ppath):
                found.append((pnum, os.path.realpath(ppath)))
        if found:
            return found
    return []


def _has_ntfs_filesystem(devpath):
    ntfs_devices = util.find_devs_with("TYPE=ntfs", no_cache=True)
    LOG.debug('ntfs_devices found = %s', ntfs_devices)
    return os.path.realpath(devpath) in ntfs_devices


def can_dev_be_reformatted(devpath, preserve_ntfs):
    """Determine if the ephemeral drive at devpath should be reformatted.

    A fresh ephemeral disk is formatted by Azure and will:
      a.) have a partition table (dos or gpt)
      b.) have 1 partition that is ntfs formatted, or
          have 2 partitions with the second partition ntfs formatted.
          (larger instances with >2TB ephemeral disk have gpt, and will
           have a microsoft reserved partition as part 1.  LP: #1686514)
      c.) the ntfs partition will have no files other than possibly
          'dataloss_warning_readme.txt'

    User can indicate that NTFS should never be destroyed by setting
    DS_CFG_KEY_PRESERVE_NTFS in dscfg.
    If data is found on NTFS, user is warned to set DS_CFG_KEY_PRESERVE_NTFS
    to make sure cloud-init does not accidentally wipe their data.
    If cloud-init cannot mount the disk to check for data, destruction
    will be allowed, unless the dscfg key is set."""
    if preserve_ntfs:
        msg = ('config says to never destroy NTFS (%s.%s), skipping checks' %
               (".".join(DS_CFG_PATH), DS_CFG_KEY_PRESERVE_NTFS))
        return False, msg

    if not os.path.exists(devpath):
        return False, 'device %s does not exist' % devpath

    LOG.debug('Resolving realpath of %s -> %s', devpath,
              os.path.realpath(devpath))

    # devpath of /dev/sd[a-z] or /dev/disk/cloud/azure_resource
    # where partitions are "<devpath>1" or "<devpath>-part1" or "<devpath>p1"
    partitions = _partitions_on_device(devpath)
    if len(partitions) == 0:
        return False, 'device %s was not partitioned' % devpath
    elif len(partitions) > 2:
        msg = ('device %s had 3 or more partitions: %s' %
               (devpath, ' '.join([p[1] for p in partitions])))
        return False, msg
    elif len(partitions) == 2:
        cand_part, cand_path = partitions[1]
    else:
        cand_part, cand_path = partitions[0]

    if not _has_ntfs_filesystem(cand_path):
        msg = ('partition %s (%s) on device %s was not ntfs formatted' %
               (cand_part, cand_path, devpath))
        return False, msg

    def count_files(mp):
        ignored = set(['dataloss_warning_readme.txt'])
        return len([f for f in os.listdir(mp) if f.lower() not in ignored])

    bmsg = ('partition %s (%s) on device %s was ntfs formatted' %
            (cand_part, cand_path, devpath))
    try:
        file_count = util.mount_cb(cand_path, count_files, mtype="ntfs",
                                   update_env_for_mount={'LANG': 'C'})
    except util.MountFailedError as e:
        if "mount: unknown filesystem type 'ntfs'" in str(e):
            return True, (bmsg + ' but this system cannot mount NTFS,'
                          ' assuming there are no important files.'
                          ' Formatting allowed.')
        return False, bmsg + ' but mount of %s failed: %s' % (cand_part, e)

    if file_count != 0:
        LOG.warning("it looks like you're using NTFS on the ephemeral disk, "
                    'to ensure that filesystem does not get wiped, set '
                    '%s.%s in config', '.'.join(DS_CFG_PATH),
                    DS_CFG_KEY_PRESERVE_NTFS)
        return False, bmsg + ' but had %d files on it.' % file_count

    return True, bmsg + ' and had no important files. Safe for reformatting.'


def address_ephemeral_resize(devpath=RESOURCE_DISK_PATH, maxwait=120,
                             is_new_instance=False, preserve_ntfs=False):
    # wait for ephemeral disk to come up
    naplen = .2
    missing = util.wait_for_files([devpath], maxwait=maxwait, naplen=naplen,
                                  log_pre="Azure ephemeral disk: ")

    if missing:
        LOG.warning("ephemeral device '%s' did not appear after %d seconds.",
                    devpath, maxwait)
        return

    result = False
    msg = None
    if is_new_instance:
        result, msg = (True, "First instance boot.")
    else:
        result, msg = can_dev_be_reformatted(devpath, preserve_ntfs)

    LOG.debug("reformattable=%s: %s", result, msg)
    if not result:
        return

    for mod in ['disk_setup', 'mounts']:
        sempath = '/var/lib/cloud/instance/sem/config_' + mod
        bmsg = 'Marker "%s" for module "%s"' % (sempath, mod)
        if os.path.exists(sempath):
            try:
                os.unlink(sempath)
                LOG.debug('%s removed.', bmsg)
            except Exception as e:
                # python3 throws FileNotFoundError, python2 throws OSError
                LOG.warning('%s: remove failed! (%s)', bmsg, e)
        else:
            LOG.debug('%s did not exist.', bmsg)
    return


def perform_hostname_bounce(hostname, cfg, prev_hostname):
    # set the hostname to 'hostname' if it is not already set to that.
    # then, if policy is not off, bounce the interface using command
    # Returns True if the network was bounced, False otherwise.
    command = cfg['command']
    interface = cfg['interface']
    policy = cfg['policy']

    msg = ("hostname=%s policy=%s interface=%s" %
           (hostname, policy, interface))
    env = os.environ.copy()
    env['interface'] = interface
    env['hostname'] = hostname
    env['old_hostname'] = prev_hostname

    if command == "builtin":
        if util.is_FreeBSD():
            command = BOUNCE_COMMAND_FREEBSD
        elif util.which('ifup'):
            command = BOUNCE_COMMAND_IFUP
        else:
            LOG.debug(
                "Skipping network bounce: ifupdown utils aren't present.")
            # Don't bounce as networkd handles hostname DDNS updates
            return False
    LOG.debug("pubhname: publishing hostname [%s]", msg)
    shell = not isinstance(command, (list, tuple))
    # capture=False, see comments in bug 1202758 and bug 1206164.
    util.log_time(logfunc=LOG.debug, msg="publishing hostname",
                  get_uptime=True, func=util.subp,
                  kwargs={'args': command, 'shell': shell, 'capture': False,
                          'env': env})
    return True


def crtfile_to_pubkey(fname, data=None):
    pipeline = ('openssl x509 -noout -pubkey < "$0" |'
                'ssh-keygen -i -m PKCS8 -f /dev/stdin')
    (out, _err) = util.subp(['sh', '-c', pipeline, fname],
                            capture=True, data=data)
    return out.rstrip()


def pubkeys_from_crt_files(flist):
    pubkeys = []
    errors = []
    for fname in flist:
        try:
            pubkeys.append(crtfile_to_pubkey(fname))
        except util.ProcessExecutionError:
            errors.append(fname)

    if errors:
        LOG.warning("failed to convert the crt files to pubkey: %s", errors)

    return pubkeys


def write_files(datadir, files, dirmode=None):

    def _redact_password(cnt, fname):
        """Azure provides the UserPassword in plain text. So we redact it"""
        try:
            root = ET.fromstring(cnt)
            for elem in root.iter():
                if ('UserPassword' in elem.tag and
                   elem.text != DEF_PASSWD_REDACTION):
                    elem.text = DEF_PASSWD_REDACTION
            return ET.tostring(root)
        except Exception:
            LOG.critical("failed to redact userpassword in %s", fname)
            return cnt

    if not datadir:
        return
    if not files:
        files = {}
    util.ensure_dir(datadir, dirmode)
    for (name, content) in files.items():
        fname = os.path.join(datadir, name)
        if 'ovf-env.xml' in name:
            content = _redact_password(content, fname)
        util.write_file(filename=fname, content=content, mode=0o600)


def invoke_agent(cmd):
    # this is a function itself to simplify patching it for test
    if cmd:
        LOG.debug("invoking agent: %s", cmd)
        util.subp(cmd, shell=(not isinstance(cmd, list)))
    else:
        LOG.debug("not invoking agent")


def find_child(node, filter_func):
    ret = []
    if not node.hasChildNodes():
        return ret
    for child in node.childNodes:
        if filter_func(child):
            ret.append(child)
    return ret


def load_azure_ovf_pubkeys(sshnode):
    # This parses a 'SSH' node formatted like below, and returns
    # an array of dicts.
    #  [{'fp': '6BE7A7C3C8A8F4B123CCA5D0C2F1BE4CA7B63ED7',
    #    'path': 'where/to/go'}]
    #
    # <SSH><PublicKeys>
    #   <PublicKey><Fingerprint>ABC</FingerPrint><Path>/ABC</Path>
    #   ...
    # </PublicKeys></SSH>
    results = find_child(sshnode, lambda n: n.localName == "PublicKeys")
    if len(results) == 0:
        return []
    if len(results) > 1:
        raise BrokenAzureDataSource("Multiple 'PublicKeys'(%s) in SSH node" %
                                    len(results))

    pubkeys_node = results[0]
    pubkeys = find_child(pubkeys_node, lambda n: n.localName == "PublicKey")

    if len(pubkeys) == 0:
        return []

    found = []
    text_node = minidom.Document.TEXT_NODE

    for pk_node in pubkeys:
        if not pk_node.hasChildNodes():
            continue

        cur = {'fingerprint': "", 'path': "", 'value': ""}
        for child in pk_node.childNodes:
            if child.nodeType == text_node or not child.localName:
                continue

            name = child.localName.lower()

            if name not in cur.keys():
                continue

            if (len(child.childNodes) != 1 or
                    child.childNodes[0].nodeType != text_node):
                continue

            cur[name] = child.childNodes[0].wholeText.strip()
        found.append(cur)

    return found


def read_azure_ovf(contents):
    try:
        dom = minidom.parseString(contents)
    except Exception as e:
        raise BrokenAzureDataSource("Invalid ovf-env.xml: %s" % e)

    results = find_child(dom.documentElement,
                         lambda n: n.localName == "ProvisioningSection")

    if len(results) == 0:
        raise NonAzureDataSource("No ProvisioningSection")
    if len(results) > 1:
        raise BrokenAzureDataSource("found '%d' ProvisioningSection items" %
                                    len(results))
    provSection = results[0]

    lpcs_nodes = find_child(provSection,
                            lambda n:
                            n.localName == "LinuxProvisioningConfigurationSet")

    if len(results) == 0:
        raise NonAzureDataSource("No LinuxProvisioningConfigurationSet")
    if len(results) > 1:
        raise BrokenAzureDataSource("found '%d' %ss" %
                                    ("LinuxProvisioningConfigurationSet",
                                     len(results)))
    lpcs = lpcs_nodes[0]

    if not lpcs.hasChildNodes():
        raise BrokenAzureDataSource("no child nodes of configuration set")

    md_props = 'seedfrom'
    md = {'azure_data': {}}
    cfg = {}
    ud = ""
    password = None
    username = None

    for child in lpcs.childNodes:
        if child.nodeType == dom.TEXT_NODE or not child.localName:
            continue

        name = child.localName.lower()

        simple = False
        value = ""
        if (len(child.childNodes) == 1 and
                child.childNodes[0].nodeType == dom.TEXT_NODE):
            simple = True
            value = child.childNodes[0].wholeText

        attrs = dict([(k, v) for k, v in child.attributes.items()])

        # we accept either UserData or CustomData.  If both are present
        # then behavior is undefined.
        if name == "userdata" or name == "customdata":
            if attrs.get('encoding') in (None, "base64"):
                ud = base64.b64decode(''.join(value.split()))
            else:
                ud = value
        elif name == "username":
            username = value
        elif name == "userpassword":
            password = value
        elif name == "hostname":
            md['local-hostname'] = value
        elif name == "dscfg":
            if attrs.get('encoding') in (None, "base64"):
                dscfg = base64.b64decode(''.join(value.split()))
            else:
                dscfg = value
            cfg['datasource'] = {DS_NAME: util.load_yaml(dscfg, default={})}
        elif name == "ssh":
            cfg['_pubkeys'] = load_azure_ovf_pubkeys(child)
        elif name == "disablesshpasswordauthentication":
            cfg['ssh_pwauth'] = util.is_false(value)
        elif simple:
            if name in md_props:
                md[name] = value
            else:
                md['azure_data'][name] = value

    defuser = {}
    if username:
        defuser['name'] = username
    if password and DEF_PASSWD_REDACTION != password:
        defuser['passwd'] = encrypt_pass(password)
        defuser['lock_passwd'] = False

    if defuser:
        cfg['system_info'] = {'default_user': defuser}

    if 'ssh_pwauth' not in cfg and password:
        cfg['ssh_pwauth'] = True

    cfg['PreprovisionedVm'] = _extract_preprovisioned_vm_setting(dom)

    return (md, ud, cfg)


def _extract_preprovisioned_vm_setting(dom):
    """Read the preprovision flag from the ovf. It should not
       exist unless true."""
    platform_settings_section = find_child(
        dom.documentElement,
        lambda n: n.localName == "PlatformSettingsSection")
    if not platform_settings_section or len(platform_settings_section) == 0:
        LOG.debug("PlatformSettingsSection not found")
        return False
    platform_settings = find_child(
        platform_settings_section[0],
        lambda n: n.localName == "PlatformSettings")
    if not platform_settings or len(platform_settings) == 0:
        LOG.debug("PlatformSettings not found")
        return False
    preprovisionedVm = find_child(
        platform_settings[0],
        lambda n: n.localName == "PreprovisionedVm")
    if not preprovisionedVm or len(preprovisionedVm) == 0:
        LOG.debug("PreprovisionedVm not found")
        return False
    return util.translate_bool(preprovisionedVm[0].firstChild.nodeValue)


def encrypt_pass(password, salt_id="$6$"):
    return crypt.crypt(password, salt_id + util.rand_str(strlen=16))


def _check_freebsd_cdrom(cdrom_dev):
    """Return boolean indicating path to cdrom device has content."""
    try:
        with open(cdrom_dev) as fp:
            fp.read(1024)
            return True
    except IOError:
        LOG.debug("cdrom (%s) is not configured", cdrom_dev)
    return False


def _get_random_seed():
    """Return content random seed file if available, otherwise,
       return None."""
    # azure / hyper-v provides random data here
    # TODO. find the seed on FreeBSD platform
    # now update ds_cfg to reflect contents pass in config
    if util.is_FreeBSD():
        return None
    return util.load_file("/sys/firmware/acpi/tables/OEM0",
                          quiet=True, decode=False)


def list_possible_azure_ds_devs():
    devlist = []
    if util.is_FreeBSD():
        cdrom_dev = "/dev/cd0"
        if _check_freebsd_cdrom(cdrom_dev):
            return [cdrom_dev]
    else:
        for fstype in ("iso9660", "udf"):
            devlist.extend(util.find_devs_with("TYPE=%s" % fstype))

    devlist.sort(reverse=True)
    return devlist


def load_azure_ds_dir(source_dir):
    ovf_file = os.path.join(source_dir, "ovf-env.xml")

    if not os.path.isfile(ovf_file):
        raise NonAzureDataSource("No ovf-env file found")

    with open(ovf_file, "rb") as fp:
        contents = fp.read()

    md, ud, cfg = read_azure_ovf(contents)
    return (md, ud, cfg, {'ovf-env.xml': contents})


class BrokenAzureDataSource(Exception):
    pass


class NonAzureDataSource(Exception):
    pass


# Legacy: Must be present in case we load an old pkl object
DataSourceAzureNet = DataSourceAzure

# Used to match classes to dependencies
datasources = [
    (DataSourceAzure, (sources.DEP_FILESYSTEM, )),
]


# Return a list of data sources that match this set of dependencies
def get_datasource_list(depends):
    return sources.list_from_depends(depends, datasources)

# vi: ts=4 expandtab