#!/usr/bin/python2
#
# The Qubes OS Project, http://www.qubes-os.org
#
# Copyright (C) 2010  Joanna Rutkowska <joanna@invisiblethingslab.com>
# Copyright (C) 2013  Marek Marczykowski <marmarek@invisiblethingslab.com>
#
# 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 os.path
import signal
import subprocess
import stat
import sys
import re

from qubes.qubes import QubesVm,register_qubes_vm_class,xs,xc,dry_run
from qubes.qubes import QubesException,QubesVmCollection
from qubes.qubes import system_path,defaults

system_path["config_template_hvm"] = '/usr/share/qubes/vm-template-hvm.conf'

defaults["hvm_disk_size"] = 20*1024*1024*1024
defaults["hvm_private_img_size"] = 2*1024*1024*1024
defaults["hvm_memory"] = 512


class QubesHVm(QubesVm):
    """
    A class that represents an HVM. A child of QubesVm.
    """

    # FIXME: logically should inherit after QubesAppVm, but none of its methods
    # are useful for HVM

    def get_attrs_config(self):
        attrs = super(QubesHVm, self).get_attrs_config()
        attrs.pop('kernel')
        attrs.pop('kernels_dir')
        attrs.pop('kernelopts')
        attrs.pop('uses_default_kernel')
        attrs.pop('uses_default_kernelopts')
        attrs['dir_path']['eval'] = 'value if value is not None else os.path.join(system_path["qubes_appvms_dir"], self.name)'
        attrs['config_file_template']['eval'] = 'system_path["config_template_hvm"]'
        attrs['drive'] = { 'save': 'str(self.drive)' }
        attrs['maxmem'].pop('save')
        attrs['timezone'] = { 'default': 'localtime', 'save': 'str(self.timezone)' }
        attrs['qrexec_installed'] = { 'default': False, 'save': 'str(self.qrexec_installed)' }
        attrs['guiagent_installed'] = { 'default' : False, 'save': 'str(self.guiagent_installed)' }
        attrs['_start_guid_first']['eval'] = 'True'
        attrs['services']['default'] = "{'meminfo-writer': False}"

        attrs['memory']['default'] = defaults["hvm_memory"]

        return attrs

    def __init__(self, **kwargs):

        super(QubesHVm, self).__init__(**kwargs)

        # Default for meminfo-writer have changed to (correct) False in the
        # same version as introduction of guiagent_installed, so for older VMs
        # with wrong setting, change is based on 'guiagent_installed' presence
        if "guiagent_installed" not in kwargs and \
            (not 'xml_element' in kwargs or kwargs['xml_element'].get('guiagent_installed') is None):
            self.services['meminfo-writer'] = False

        # HVM normally doesn't support dynamic memory management
        if not ('meminfo-writer' in self.services and self.services['meminfo-writer']):
            self.maxmem = self.memory

        self._stubdom_guid_process = None

    @property
    def type(self):
        return "HVM"

    def is_appvm(self):
        return True

    @classmethod
    def is_template_compatible(cls, template):
        if template and (not template.is_template() or template.type != "TemplateHVM"):
            return False
        return True

    def get_clone_attrs(self):
        attrs = super(QubesHVm, self).get_clone_attrs()
        attrs.remove('kernel')
        attrs.remove('uses_default_kernel')
        attrs.remove('kernelopts')
        attrs.remove('uses_default_kernelopts')
        attrs += [ 'timezone' ]
        attrs += [ 'qrexec_installed' ]
        attrs += [ 'guiagent_installed' ]
        return attrs

    def create_on_disk(self, verbose, source_template = None):
        if dry_run:
            return

        if verbose:
            print >> sys.stderr, "--> Creating directory: {0}".format(self.dir_path)
        os.mkdir (self.dir_path)

        if verbose:
            print >> sys.stderr, "--> Creating icon symlink: {0} -> {1}".format(self.icon_path, self.label.icon_path)
        os.symlink (self.label.icon_path, self.icon_path)

        self.create_config_file()

        # create empty disk
        if self.template is None:
            if verbose:
                print >> sys.stderr, "--> Creating root image: {0}".\
                    format(self.root_img)
            f_root = open(self.root_img, "w")
            f_root.truncate(defaults["hvm_disk_size"])
            f_root.close()

        # create empty private.img
        if verbose:
            print >> sys.stderr, "--> Creating private image: {0}".\
                format(self.private_img)
        f_private = open(self.private_img, "w")
        f_private.truncate(defaults["hvm_private_img_size"])
        f_private.close()

        # fire hooks
        for hook in self.hooks_create_on_disk:
            hook(self, verbose, source_template=source_template)

    def get_disk_utilization_private_img(self):
        return self.get_disk_usage(self.private_img)

    def get_private_img_sz(self):
        if not os.path.exists(self.private_img):
            return 0

        return os.path.getsize(self.private_img)

    def resize_private_img(self, size):
        assert size >= self.get_private_img_sz(), "Cannot shrink private.img"

        if self.is_running():
            raise NotImplementedError("Online resize of HVM's private.img not implemented, shutdown the VM first")

        f_private = open (self.private_img, "a+b")
        f_private.truncate (size)
        f_private.close ()

    def get_rootdev(self, source_template=None):
        if self.template:
            return "'script:snapshot:{template_root}:{volatile},xvda,w',".format(
                    template_root=self.template.root_img,
                    volatile=self.volatile_img)
        else:
            return "'script:file:{root_img},xvda,w',".format(root_img=self.root_img)

    def get_config_params(self, source_template=None):

        params = super(QubesHVm, self).get_config_params(source_template=source_template)

        params['volatiledev'] = ''
        if self.drive:
            type_mode = ":cdrom,r"
            drive_path = self.drive
            # leave empty to use standard syntax in case of dom0
            backend_domain = ""
            if drive_path.startswith("hd:"):
                type_mode = ",w"
                drive_path = drive_path[3:]
            elif drive_path.startswith("cdrom:"):
                type_mode = ":cdrom,r"
                drive_path = drive_path[6:]
            backend_split = re.match(r"^([a-zA-Z0-9-]*):(.*)", drive_path)
            if backend_split:
                backend_domain = "," + backend_split.group(1)
                drive_path = backend_split.group(2)
            if backend_domain.lower() == "dom0":
                backend_domain = ""

            # FIXME: os.stat will work only when backend in dom0...
            stat_res = None
            if backend_domain == "":
                stat_res = os.stat(drive_path)
            if stat_res and stat.S_ISBLK(stat_res.st_mode):
                params['otherdevs'] = "'phy:%s,xvdc%s%s'," % (drive_path, type_mode, backend_domain)
            else:
                params['otherdevs'] = "'script:file:%s,xvdc%s%s'," % (drive_path, type_mode, backend_domain)
        else:
             params['otherdevs'] = ''

        if self.timezone.lower() == 'localtime':
             params['localtime'] = '1'
             params['timeoffset'] = '0'
        elif self.timezone.isdigit():
            params['localtime'] = '0'
            params['timeoffset'] = self.timezone
        else:
            print >>sys.stderr, "WARNING: invalid 'timezone' value: %s" % self.timezone
            params['localtime'] = '0'
            params['timeoffset'] = '0'
        return params

    def verify_files(self):
        if dry_run:
            return

        if not os.path.exists (self.dir_path):
            raise QubesException (
                    "VM directory doesn't exist: {0}".\
                    format(self.dir_path))

        if self.is_updateable() and not os.path.exists (self.root_img):
            raise QubesException (
                    "VM root image file doesn't exist: {0}".\
                    format(self.root_img))

        if not os.path.exists (self.private_img):
            print >>sys.stderr, "WARNING: Creating empty VM private image file: {0}".\
                format(self.private_img)
            f_private = open(self.private_img, "w")
            f_private.truncate(defaults["hvm_private_img_size"])
            f_private.close()

        # fire hooks
        for hook in self.hooks_verify_files:
            hook(self)

        return True

    def reset_volatile_storage(self, **kwargs):
        assert not self.is_running(), "Attempt to clean volatile image of running VM!"

        source_template = kwargs.get("source_template", self.template)

        if source_template is None:
            # Nothing to do on non-template based VM
            return

        if os.path.exists (self.volatile_img):
            if self.debug:
                if os.path.getmtime(self.template.root_img) > os.path.getmtime(self.volatile_img):
                    if kwargs.get("verbose", False):
                        print >>sys.stderr, "--> WARNING: template have changed, resetting root.img"
                else:
                    if kwargs.get("verbose", False):
                        print >>sys.stderr, "--> Debug mode: not resetting root.img"
                        print >>sys.stderr, "--> Debug mode: if you want to force root.img reset, either update template VM, or remove volatile.img file"
                    return
            os.remove (self.volatile_img)

        f_volatile = open (self.volatile_img, "w")
        f_root = open (self.template.root_img, "r")
        f_root.seek(0, os.SEEK_END)
        f_volatile.truncate (f_root.tell()) # make empty sparse file of the same size as root.img
        f_volatile.close ()
        f_root.close()

    @property
    def vif(self):
        if self.xid < 0:
            return None
        if self.netvm is None:
            return None
        return "vif{0}.+".format(self.stubdom_xid)

    @property
    def mac(self):
        if self._mac is not None:
            return self._mac
        elif self.template is not None:
            return self.template.mac
        else:
            return "00:16:3E:5E:6C:{qid:02X}".format(qid=self.qid)

    @mac.setter
    def mac(self, value):
        self._mac = value

    def run(self, command, **kwargs):
        if self.qrexec_installed:
            if 'gui' in kwargs and kwargs['gui']==False:
                command = "nogui:" + command
            return super(QubesHVm, self).run(command, **kwargs)
        else:
            raise QubesException("Needs qrexec agent installed in VM to use this function. See also qvm-prefs.")

    @property
    def stubdom_xid(self):
        if self.xid < 0:
            return -1

        stubdom_xid_str = xs.read('', '/local/domain/%d/image/device-model-domid' % self.xid)
        if stubdom_xid_str is not None:
            return int(stubdom_xid_str)
        else:
            return -1

    def start(self, *args, **kwargs):
        if self.template and self.template.is_running():
            raise QubesException("Cannot start the HVM while its template is running")
        try:
            super(QubesHVm, self).start(*args, **kwargs)
        except QubesException as e:
            if xc.physinfo()['virt_caps'].count('hvm') == 0:
                raise QubesException("Cannot start HVM without VT-x/AMD-v enabled")
            else:
                raise

    def start_stubdom_guid(self):
        cmdline = [system_path["qubes_guid_path"],
                "-d", str(self.stubdom_xid),
                "-c", self.label.color,
                "-i", self.label.icon_path,
                "-l", str(self.label.index)]
        retcode = subprocess.call (cmdline)
        if (retcode != 0) :
            raise QubesException("Cannot start qubes-guid!")

    def start_guid(self, verbose = True, notify_function = None,
            before_qrexec=False, **kwargs):
        # If user force the guiagent, start_guid will mimic a standard QubesVM
        if self.guiagent_installed and not before_qrexec:
            super(QubesHVm, self).start_guid(verbose, notify_function, extra_guid_args=["-Q"], **kwargs)
            stubdom_guid_pidfile = '/var/run/qubes/guid-running.%d' % self.stubdom_xid
            if os.path.exists(stubdom_guid_pidfile):
                try:
                    stubdom_guid_pid = int(open(stubdom_guid_pidfile, 'r').read())
                    os.kill(stubdom_guid_pid, signal.SIGTERM)
                except Exception as ex:
                    print >> sys.stderr, "WARNING: Failed to kill stubdom gui daemon: %s" % str(ex)
        else:
            if verbose:
                print >> sys.stderr, "--> Starting Qubes GUId (full screen)..."
            self.start_stubdom_guid()

    def start_qrexec_daemon(self, **kwargs):
        if not self.qrexec_installed:
            if kwargs.get('verbose', False):
                print >> sys.stderr, "--> Starting the qrexec daemon..."
            xid = self.get_xid()
            qrexec_env = os.environ
            qrexec_env['QREXEC_STARTUP_NOWAIT'] = '1'
            retcode = subprocess.call ([system_path["qrexec_daemon_path"], str(xid), self.name, self.default_user], env=qrexec_env)
            if (retcode != 0) :
                self.force_shutdown(xid=xid)
                raise OSError ("ERROR: Cannot execute qrexec-daemon!")
        else:
            super(QubesHVm, self).start_qrexec_daemon(**kwargs)

            if self._start_guid_first:
                if kwargs.get('verbose'):
                    print >> sys.stderr, "--> Waiting for user '%s' login..." % self.default_user

                self.wait_for_session(notify_function=kwargs.get('notify_function', None))

    def create_xenstore_entries(self, xid = None):
        if dry_run:
            return

        super(QubesHVm, self).create_xenstore_entries(xid)

        if xid is None:
            xid = self.xid

        domain_path = xs.get_domain_path(xid)

        # Prepare xenstore directory for tools advertise
        xs.write('',
                "{0}/qubes-tools".format(domain_path),
                '')

        # Allow VM writes there
        xs.set_permissions('', '{0}/qubes-tools'.format(domain_path),
                [{ 'dom': xid }])

    def suspend(self):
        if dry_run:
            return

        if not self.is_running() and not self.is_paused():
            raise QubesException ("VM not running!")

        self.pause()

    def pause(self):
        if dry_run:
            return

        xc.domain_pause(self.stubdom_xid)
        super(QubesHVm, self).pause()

    def unpause(self):
        if dry_run:
            return

        xc.domain_unpause(self.stubdom_xid)
        super(QubesHVm, self).unpause()

    def is_guid_running(self):
        # If user force the guiagent, is_guid_running will mimic a standard QubesVM
        if self.guiagent_installed:
            return super(QubesHVm, self).is_guid_running()
        else:
            xid = self.stubdom_xid
            if xid < 0:
                return False
            if not os.path.exists('/var/run/qubes/guid-running.%d' % xid):
                return False
            return True


register_qubes_vm_class(QubesHVm)