#
# Helper functions for determining if libvirt supports certain features
#
# Copyright 2009  Red Hat, Inc.
# Cole Robinson <crobinso@redhat.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 libvirt
from virtinst import uriutil


# Flags for check_conn_support
SUPPORT_CONN_STORAGE = 0
SUPPORT_CONN_FINDPOOLSOURCES = 1
SUPPORT_CONN_NODEDEV = 2
SUPPORT_CONN_KEYMAP_AUTODETECT = 3
SUPPORT_CONN_GETHOSTNAME = 4
SUPPORT_CONN_DOMAIN_VIDEO = 5
SUPPORT_CONN_NETWORK = 7
SUPPORT_CONN_INTERFACE = 8
SUPPORT_CONN_MAXVCPUS_XML = 9
SUPPORT_CONN_STREAM = 10

# Flags for check_domain_support
SUPPORT_DOMAIN_GETVCPUS = 1000
SUPPORT_DOMAIN_XML_SECURE = 1001
SUPPORT_DOMAIN_XML_INACTIVE = 1002
SUPPORT_DOMAIN_MANAGED_SAVE = 1003
SUPPORT_DOMAIN_MIGRATE_DOWNTIME = 1004
SUPPORT_DOMAIN_JOB_INFO = 1005
SUPPORT_DOMAIN_MAXVCPUS_XML = 1006
SUPPORT_DOMAIN_CONSOLE_STREAM = 1007
SUPPORT_DOMAIN_SET_METADATA = 1008

# Flags for check_pool_support
SUPPORT_STORAGE_CREATEVOLFROM = 2000
SUPPORT_STORAGE_UPLOAD = 2001

# Flags for check_nodedev_support
SUPPORT_NODEDEV_PCI_DETACH = 3000

# Flags for check_interface_support
SUPPORT_INTERFACE_XML_INACTIVE = 4000

# Flags for check_conn_hv_support
SUPPORT_CONN_HV_VIRTIO = 5000
SUPPORT_CONN_HV_SKIP_DEFAULT_ACPI = 5001
SUPPORT_CONN_HV_SOUND_AC97 = 5002
SUPPORT_CONN_HV_SOUND_ICH6 = 5003
SUPPORT_CONN_HV_GRAPHICS_SPICE = 5004
SUPPORT_CONN_HV_CHAR_SPICEVMC = 5005
SUPPORT_CONN_HV_DIRECT_INTERFACE = 5006
SUPPORT_CONN_HV_FILESYSTEM = 5007

# Flags for check_stream_support
SUPPORT_STREAM_UPLOAD = 6000

"""
Possible keys:

  - "version" : Minimum libvirt version required for this feature. Not used
                if 'args' provided

  - "force_version" : Demand that version check is met for the checked
                      libvirt version. Normally we will make a best effort
                      attempt, because determining the daemon version depends
                      on a fairly new API call getLibVersion. So for things like
                      testing API availability (e.g. createXMLFrom) we won't
                      force the check, but for things like XML options (AC97)
                      we want to be ABSOLUTELY SURE it is supported so we
                      don't enable it by default and break guest creation.
                      This isn't required for versions after >= 0.7.3

  - "function" : Function name to check exists. If object not specified,
                 function is checked against libvirt module.

  - "args": Argument tuple to actually test object.function with.

  - "flag": A flag to check exists. This will be appended to the argument
            list if args are provided, otherwise we will only check against
            the local libvirt version.

  - "drv_version" : A list of tuples of the form
                   (driver name (e.g qemu, xen, lxc), minimum supported version)
                   If a hypervisor is not listed, it is assumed to be NOT
                   SUPPORTED.

  - "drv_libvirt_version" : List of tuples, similar to drv_version, but
                            the version number is minimum supported _libvirt_
                            version
  - "hv_version" : A list of tuples of the same form as drv_version, however
                   listing the actual <domain type='%s'/> from the XML.
                   example: 'kvm'
"""

_support_dict = {
    SUPPORT_CONN_STORAGE : {
        "function" : "virConnect.listStoragePools",
        "args" : (),
    },

    SUPPORT_CONN_NODEDEV : {
        "function" : "virConnect.listDevices",
        "args" : (None, 0),
    },

    SUPPORT_CONN_FINDPOOLSOURCES : {
        "function" : "virConnect.findStoragePoolSources",
    },

    SUPPORT_CONN_KEYMAP_AUTODETECT : {
        "drv_version" : [ ("qemu", 11000) ],
    },

    SUPPORT_CONN_GETHOSTNAME : {
        "function" : "virConnect.getHostname()",
        "args" : (),
    },

    SUPPORT_CONN_DOMAIN_VIDEO : {
        "version" : 6005,
    },


    SUPPORT_CONN_NETWORK : {
        "function" : "virConnect.listNetworks",
        "args" : (),
    },

    SUPPORT_CONN_INTERFACE : {
        "function" : "virConnect.listInterfaces",
        "args" : (),
    },

    SUPPORT_CONN_MAXVCPUS_XML : {
        "version" : 8005,
    },

    SUPPORT_CONN_STREAM : {
        # Earliest version with working bindings
        "version" : 9003,
        "function" : "virConnect.newStream",
        "args" : (0,),
    },


    # Domain checks
    SUPPORT_DOMAIN_GETVCPUS : {
        "function" : "virDomain.vcpus",
        "args" : (),
    },

    SUPPORT_DOMAIN_XML_INACTIVE : {
        "function" : "virDomain.XMLDesc",
        "args" : (),
        "flag" : "VIR_DOMAIN_XML_INACTIVE",
    },

    SUPPORT_DOMAIN_XML_SECURE : {
        "function" : "virDomain.XMLDesc",
        "args" : (),
        "flag" : "VIR_DOMAIN_XML_SECURE",
    },

    SUPPORT_DOMAIN_MANAGED_SAVE : {
        "function" : "virDomain.hasManagedSaveImage",
        "args" : (0,),
    },

    SUPPORT_DOMAIN_MIGRATE_DOWNTIME : {
        "function" : "virDomain.migrateSetMaxDowntime",
        # Use a bogus flags value, so that we don't overwrite existing
        # downtime value
        "args" : (30, 12345678),
    },

    SUPPORT_DOMAIN_JOB_INFO : {
        "function" : "virDomain.jobInfo",
        "args" : (),
    },

    SUPPORT_DOMAIN_CONSOLE_STREAM : {
        "version" : 9003,
    },

    SUPPORT_DOMAIN_SET_METADATA : {
        "version" : 9010,
    },


    # Pool checks
    # This can't ever require a pool object for back compat reasons
    SUPPORT_STORAGE_CREATEVOLFROM : {
        "function" : "virStoragePool.createXMLFrom",
        "version" : 6004,
    },

    # Nodedev checks
    # This can't ever require a nodedev object for back compat reasons
    SUPPORT_NODEDEV_PCI_DETACH : {
        "function" : "virNodeDevice.dettach",
        "version" : 6001,
    },

    # Interface checks
    SUPPORT_INTERFACE_XML_INACTIVE : {
        "function" : "virInterface.XMLDesc",
        "args" : (),
        "flag" : "VIR_INTERFACE_XML_INACTIVE",
    },

    # Conn HV checks
    SUPPORT_CONN_HV_VIRTIO : {
        "drv_version": [ ("qemu", 0) ],
        "hv_version" : [ ("kvm", 0) ],
    },

    SUPPORT_CONN_HV_SKIP_DEFAULT_ACPI : {
        "drv_version" : [ ("xen", -3001000)],
    },

    SUPPORT_CONN_HV_SOUND_AC97 : {
        "version" : 6000,
        "force_version" : True,
        "drv_version" : [ ("qemu", 11000), ],
    },

    SUPPORT_CONN_HV_SOUND_ICH6 : {
        "version" : 8008,
        "drv_version" : [ ("qemu", 14000), ],
        "rhel6_drv_version" : [ ("qemu", 12001) ],
        "rhel6_version" : 8007,
    },

    SUPPORT_CONN_HV_GRAPHICS_SPICE : {
        "version" : 8006,
        "drv_version" : [ ("qemu", 14000), ],
    },

    SUPPORT_CONN_HV_CHAR_SPICEVMC : {
        "version" : 8008,
        "drv_version" : [ ("qemu", 14000), ],
    },
    SUPPORT_CONN_HV_DIRECT_INTERFACE : {
        "version" : 8007,
        "drv_version" : [ ("qemu", 0), ],
    },
    SUPPORT_CONN_HV_FILESYSTEM : {
        "drv_version" : [ ("qemu", 13000),
                          ("lxc", 0),
                          ("openvz", 0),
                          ("test", 0)],
        "drv_libvirt_version" : [ ("qemu", 8005),
                                  ("lxc", 0),
                                  ("openvz", 0),
                                  ("test", 0)],
    },


    SUPPORT_STREAM_UPLOAD : {
        # Latest I tested with, and since we will use it by default
        # for URL installs, want to be sure it works
        "version" : 9004,
    },
}

# XXX: RHEL6 has lots of feature backports, and since libvirt doesn't
# really offer any XML feature introspection, we have to use hacks to
# make sure we aren't generating bogus config on non RHEL
_rhel6 = False
def _set_rhel6(val):
    global _rhel6
    _rhel6 = bool(val)
def _get_rhel6():
    return _rhel6

# Pull a connection object from the passed libvirt object
def _get_conn_from_object(obj):
    if not hasattr(obj, "_conn"):
        return obj
    return obj._conn

# Check that command is present in the python bindings, and return the
# the requested function
def _get_command(funcname, objname=None, obj=None):
    if not obj:
        obj = libvirt

        if objname:
            if not hasattr(libvirt, objname):
                return None
            obj = getattr(libvirt, objname)

    if not hasattr(obj, funcname):
        return None

    return getattr(obj, funcname)

# Make sure libvirt object 'objname' has function 'funcname'
def _has_command(funcname, objname=None, obj=None):
    return bool(_get_command(funcname, objname, obj))

# Make sure libvirt object has flag 'flag_name'
def _get_flag(flag_name):
    return _get_command(flag_name)

# Try to call the passed function, and look for signs that libvirt or driver
# doesn't support it
def _try_command(func, args, check_all_error=False):
    try:
        func(*args)

    except libvirt.libvirtError, e:
        if is_error_nosupport(e):
            return False

        if check_all_error:
            return False

    except Exception:
        # Other python exceptions likely mean the bindings are horked
        return False

    return True

# Version of the local libvirt library
def _local_lib_ver():
    return libvirt.getVersion()

# Version of libvirt library/daemon on the connection (could be remote)
def _daemon_lib_ver(conn, uri, force_version, minimum_libvirt_version):
    # Always force the required version if it's after the version which
    # has getLibVersion
    if force_version or minimum_libvirt_version >= 7004:
        default_ret = 0
    else:
        default_ret = 100000000000

    if not uriutil.is_uri_remote(uri, conn=conn):
        return _local_lib_ver()

    if not _has_command("getLibVersion", obj=conn):
        return default_ret

    if not _try_command(getattr(conn, "getLibVersion"), ()):
        return default_ret

    return conn.getLibVersion()

# Return the hypervisor version
def _hv_ver(conn, uri):
    drv_type = uriutil.get_uri_driver(uri)
    args = ()

    cmd = _get_command("getVersion", obj=conn)
    if not cmd:
        cmd = _get_command("getVersion")
        args = (drv_type,)

    if not cmd:
        return 0

    if not _try_command(cmd, args):
        return 0

    try:
        ret = cmd(*args)
        if type(ret) == tuple:
            ret = ret[1]
    except libvirt.libvirtError:
        ret = 0

    return ret

def _split_function_name(function):
    if not function:
        return (None, None)

    output = function.split(".")
    if len(output) == 1:
        return (None, output[0])
    else:
        return (output[0], output[1])

def _check_support(conn, feature, data=None):
    """
    Attempt to determine if a specific libvirt feature is support given
    the passed connection.

    @param conn: Libvirt connection to check feature on
    @type  conn: virConnect
    @param feature: Feature type to check support for
    @type  feature: One of the SUPPORT_* flags
    @param data: Option libvirt object to use in feature checking
    @type  data: Could be virDomain, virNetwork, virStoragePool,
                hv name, etc

    @returns: True if feature is supported, False otherwise
    """
    support_info = _support_dict[feature]
    key_list = support_info.keys()

    if not isinstance(conn, libvirt.virConnect):
        raise ValueError(_("'conn' must be a virConnect instance."))

    def get_value(key):
        if key in key_list:
            key_list.remove(key)
        return support_info.get(key)

    uri = conn.getURI()
    drv_type = uriutil.get_uri_driver(uri)
    is_rhel6 = _get_rhel6()
    force_version = get_value("force_version") or False

    minimum_libvirt_version = get_value("version") or 0
    rhel6_min = get_value("rhel6_version") or minimum_libvirt_version
    if is_rhel6:
        minimum_libvirt_version = rhel6_min

    drv_version = get_value("drv_version") or []
    rhel6_drv_version = get_value("rhel6_drv_version") or drv_version
    if is_rhel6:
        drv_version = rhel6_drv_version

    drv_libvirt_version = get_value("drv_libvirt_version") or []

    hv_version = get_value("hv_version") or []
    object_name, function_name = _split_function_name(get_value("function"))
    args = get_value("args")
    flag = get_value("flag")

    actual_lib_ver = _local_lib_ver()
    actual_daemon_ver = _daemon_lib_ver(conn, uri, force_version,
                                        minimum_libvirt_version)
    actual_drv_ver = _hv_ver(conn, uri)

    # Make sure there are no keys left in the key_list. This will
    # ensure we didn't mistype anything above, or in the support_dict
    if key_list:
        raise RuntimeError("Unknown keys in the support_dict: %s" % key_list)

    if function_name:
        # Make sure function is present in either libvirt module or
        # object_name class
        flag_tuple = ()

        if not _has_command(function_name, objname=object_name):
            return False

        if flag:
            found_flag = _get_flag(flag)
            if not bool(found_flag):
                return False
            flag_tuple = (found_flag,)

        if args is not None:
            classobj = None

            # If function requires an object, make sure the passed obj
            # is of the correct type
            if object_name:
                classobj = _get_command(object_name)
                if not isinstance(data, classobj):
                    raise ValueError("Passed obj with args must be of type " +
                                     str(classobj))

            cmd = _get_command(function_name, obj=data)

            # Function with args specified is all the proof we need
            ret = _try_command(cmd, args + flag_tuple,
                               check_all_error=bool(flag_tuple))
            return ret

    # Check that local libvirt version is sufficient
    if minimum_libvirt_version > actual_lib_ver:
        return False

    # Check that daemon version is sufficient
    if minimum_libvirt_version > actual_daemon_ver:
        return False

    # If driver specific version info specified, try to verify
    if drv_version:
        found = False
        for drv, min_drv_ver in drv_version:
            if drv != drv_type:
                continue

            if min_drv_ver < 0:
                if actual_drv_ver <= -min_drv_ver:
                    found = True
                    break
            else:
                if actual_drv_ver >= min_drv_ver:
                    found = True
                    break

        if not found:
            return False

    if drv_libvirt_version:
        found = False
        for drv, min_lib_ver in drv_libvirt_version:
            if drv != drv_type:
                continue

            if min_lib_ver < 0:
                if actual_lib_ver <= -min_lib_ver:
                    found = True
                    break
            else:
                if actual_lib_ver >= min_lib_ver:
                    found = True
                    break

        if not found:
            return False

    if hv_version:
        found = False
        hv_type = data
        for hv, min_hv_ver in hv_version:
            if hv != hv_type:
                continue

            # XXX: No HV specific version info, just use driver version
            if min_hv_ver < 0:
                if actual_drv_ver <= -min_hv_ver:
                    found = True
                    break
            else:
                if actual_drv_ver >= min_hv_ver:
                    found = True
                    break

        if not found:
            return False

    return True

# Public API below

def is_error_nosupport(err):
    """
    Check if passed exception indicates that the called libvirt command isn't
    supported

    @param err: Exception raised from command call
    @returns: True if command isn't supported, False if we can't determine
    """
    if not isinstance(err, libvirt.libvirtError):
        return False

    if (err.get_error_code() == libvirt.VIR_ERR_RPC or
        err.get_error_code() == libvirt.VIR_ERR_NO_SUPPORT):
        return True

    return False

def support_threading():
    return bool(_local_lib_ver() >= 6000)
def support_openauth():
    return bool(_local_lib_ver() >= 4000)

def check_conn_support(conn, feature):
    return _check_support(conn, feature, conn)

def check_conn_hv_support(conn, feature, hv):
    return _check_support(conn, feature, hv)

def check_domain_support(dom, feature):
    return _check_support(_get_conn_from_object(dom), feature, dom)

def check_pool_support(pool, feature):
    return _check_support(_get_conn_from_object(pool), feature, pool)

def check_nodedev_support(nodedev, feature):
    return _check_support(_get_conn_from_object(nodedev), feature, nodedev)

def check_interface_support(nodedev, feature):
    return _check_support(_get_conn_from_object(nodedev), feature, nodedev)

def check_stream_support(conn, feature):
    return (check_conn_support(conn, SUPPORT_CONN_STREAM) and
            _check_support(conn, feature, conn))