#!/usr/bin/python2
#
# Python client for checking periodically for posted actions
# on the Spacewalk servers.
#
# Copyright (c) 2000--2018 Red Hat, Inc.
#
# This software is licensed to you under the GNU General Public License,
# version 2 (GPLv2). There is NO WARRANTY for this software, express or
# implied, including the implied warranties of MERCHANTABILITY or FITNESS
# FOR A PARTICULAR PURPOSE. You should have received a copy of GPLv2
# along with this software; if not, see
# http://www.gnu.org/licenses/old-licenses/gpl-2.0.txt.
#
# Red Hat trademarks are not licensed under GPLv2. No permission is
# granted to use or replicate Red Hat trademarks that are incorporated
# in this software or its documentation.
#
# In addition, as a special exception, the copyright holders give
# permission to link the code of portions of this program with the
# OpenSSL library under certain conditions as described in each
# individual source file, and distribute linked combinations
# including the two.
# You must obey the GNU General Public License in all respects
# for all of the code used other than OpenSSL.  If you modify
# file(s) with this exception, you may extend this exception to your
# version of the file(s), but you are not obligated to do so.  If you
# do not wish to do so, delete this exception statement from your
# version.  If you delete this exception statement from all source
# files in the program, then also delete it here.

import base64
import os
import sys
import socket

import gettext
t = gettext.translation('rhn-client-tools', fallback=True)
# Python 3 translations don't have a ugettext method
if not hasattr(t, 'ugettext'):
    t.ugettext = t.gettext
_ = t.ugettext

import OpenSSL

# disable sgmlop module
# it breaks rhn_check when loaded during xmlrpclib import
sys.modules['sgmlop'] = None

from up2date_client import getMethod
from up2date_client import up2dateErrors
from up2date_client import up2dateAuth
from up2date_client import up2dateLog
from up2date_client import rpcServer
from up2date_client import config
from up2date_client import clientCaps
from up2date_client import capabilities
from up2date_client import rhncli, rhnserver

from rhn import SSL
from rhn import rhnLockfile
from rhn.i18n import bstr, sstr
from rhn.tb import raise_with_tb

try: # python2
    import xmlrpclib
except ImportError: # python3
    import xmlrpc.client as xmlrpclib
    long = int

if 'sgmlop' in sys.modules:
    del sys.modules['sgmlop']

cfg = config.initUp2dateConfig()
log = up2dateLog.initLog()

# action version we understand
ACTION_VERSION = 2

# lock file to check if we're disabled at the server's request
DISABLE_FILE = "/etc/sysconfig/rhn/disable"

# Actions that will run each time we execute.
LOCAL_ACTIONS = [("packages.checkNeedUpdate", ("rhnsd=1",))]


class CheckCli(rhncli.RhnCli):

    def __init__(self):
        super(CheckCli, self).__init__()

        self.rhns_ca_cert = cfg['sslCACert']
        self.server = None

    def main(self):
        """ Process all the actions we have in the queue. """
        CheckCli.__check_instance_lock()
        CheckCli.__check_rhn_disabled()
        CheckCli.__check_has_system_id()

        self.server = CheckCli.__get_server()

        CheckCli.__update_system_id()

        self.__run_remote_actions()
        CheckCli.__run_local_actions()

        s = rhnserver.RhnServer()
        if s.capabilities.hasCapability('staging_content', 1) and cfg['stagingContent'] != 0:
             self.__check_future_actions()

        sys.exit(0)

    def __get_action(self, status_report):
        try:
            action = self.server.queue.get(up2dateAuth.getSystemId(),
                ACTION_VERSION, status_report)

            return action
        except xmlrpclib.Fault:
            f = sys.exc_info()[1]
            if f.faultCode == -31:
                raise_with_tb(up2dateErrors.InsuffMgmntEntsError(f.faultString))
            else:
                print("Could not retrieve action item from server %s" % self.server)
                print("Error code: %d%s" % (f.faultCode, f.faultString))
            sys.exit(-1)
        # XXX: what if no SSL in socket?
        except SSL.socket_error:
            print("ERROR: SSL handshake to %s failed" % self.server)
            print("""
            This could signal that you are *NOT* talking to a server
            whose certificate was signed by a Certificate Authority
            listed in the %s file or that the
            RHNS-CA-CERT file is invalid.""" % self.rhns_ca_cert)
            sys.exit(-1)
        except socket.error:
            print("Could not retrieve action from %s.\n"\
                  "Possible networking problem?" % str(self.server))
            sys.exit(-1)
        except up2dateErrors.ServerCapabilityError:
            print(sys.exc_info()[1])
            sys.exit(1)
        except OpenSSL.SSL.Error:
            print("ERROR: SSL errors detected")
            print("%s" % sys.exc_info()[1])
            sys.exit(-1)

    def __query_future_actions(self, time_window):
        try:
            actions = self.server.queue.get_future_actions(up2dateAuth.getSystemId(),
                time_window)
            return actions
        except xmlrpclib.Fault:
            f = sys.exc_info()[1]
            if f.faultCode == -31:
                raise_with_tb(up2dateErrors.InsuffMgmntEntsError(f.faultString))
            else:
                print("Could not retrieve action item from server %s" % self.server)
                print("Error code: %d%s" % (f.faultCode, f.faultString))
            sys.exit(-1)
        # XXX: what if no SSL in socket?
        except SSL.socket_error:
            print("ERROR: SSL handshake to %s failed" % self.server)
            print("""
            This could signal that you are *NOT* talking to a server
            whose certificate was signed by a Certificate Authority
            listed in the %s file or that the
            RHNS-CA-CERT file is invalid.""" % self.rhns_ca_cert)
            sys.exit(-1)
        except socket.error:
            print("Could not retrieve action from %s.\n"\
                  "Possible networking problem?" % str(self.server))
            sys.exit(-1)
        except up2dateErrors.ServerCapabilityError:
            print(sys.exc_info()[1])
            sys.exit(1)
        except SSL.Error:
            print("ERROR: SSL errors detected")
            print("%s" % sys.exc_info()[1])
            sys.exit(-1)

    def __fetch_future_action(self, action):
        """ Fetch one specific action from rhnParent """
        # TODO
        pass

    def __check_future_actions(self):
        """ Retrieve scheduled actions and cache them if possible """
        time_window = cfg['stagingContentWindow'] or 24;
        actions = self.__query_future_actions(time_window)
        for action in actions:
            self.handle_action(action, cache_only=1)

    def __run_remote_actions(self):
        # the list of caps the client needs
        caps = capabilities.Capabilities()

        status_report = CheckCli.__build_status_report()

        action = self.__get_action(status_report)
        while action != "" and action != {}:
            self.__verify_server_capabilities(caps)

            if self.is_valid_action(action):
                try:
                    up2dateAuth.updateLoginInfo()
                except up2dateErrors.ServerCapabilityError:
                    print(sys.exc_info()[1])
                    sys.exit(1)
                self.handle_action(action)

            action = self.__get_action(status_report)

    def __verify_server_capabilities(self, caps):
        response_headers = self.server.get_response_headers()
        caps.populate(response_headers)
        # do we actually want to validte here?
        try:
            caps.validate()
        except up2dateErrors.ServerCapabilityError:
            print(sys.exc_info()[1])
            sys.exit(1)

    def __parse_action_data(self, action):
        """ Parse action data and returns (method, params) """
        data = action['action']
        parser, decoder = xmlrpclib.getparser()
        parser.feed(bstr(data))
        parser.close()
        params = decoder.close()
        method = decoder.getmethodname()
        return (method, params)

    def submit_response(self, action_id, status, message, data):
        """ Submit a response for an action_id. """

        # get a new server object with fresh headers
        self.server = CheckCli.__get_server()

        try:
            ret = self.server.queue.submit(up2dateAuth.getSystemId(),
                                      action_id, status, message, data)
        except xmlrpclib.Fault:
            f = sys.exc_info()[1]
            print("Could not submit results to server %s" % self.server)
            print("Error code: %d%s" % (f.faultCode, f.faultString))
            sys.exit(-1)
        # XXX: what if no SSL in socket?
        except SSL.socket_error:
            print("ERROR: SSL handshake to %s failed" % self.server)
            print("""
            This could signal that you are *NOT* talking to a server
            whose certificate was signed by a Certificate Authority
            listed in the %s file or that the
            RHNS-CA-CERT file is invalid.""" % self.rhns_ca_cert)
            sys.exit(-1)
        except socket.error:
            print("Could not submit to %s.\n"\
                  "Possible networking problem?" % str(self.server))
            sys.exit(-1)
        return ret

    def handle_action(self, action, cache_only=None):
        """ Wrapper handler for the action we're asked to do. """
        log.log_debug("handle_action", action)
        log.log_debug("handle_action actionid = %s, version = %s" % (
            action['id'], action['version']))

        data = {}
        action_lock = '/var/lib/up2date/action.%s' % str(action['id'])
        if os.path.exists(action_lock):
            ret = 255
            if not cache_only:
                if os.path.getsize(action_lock) > 0:
                    data['base64enc'] = 1
                    data['return_code'] = 255
                    data['process_start'] = '1970-01-01 00:00:00'  # dummy values as we have no idea of start
                    data['process_end'] = '1970-01-01 00:00:00'    # and especially about the end
                    with open(action_lock) as f:
                        data['output'] = base64.encodestring(f.read())
                log.log_debug("Sending back response", (255, "Previous run of action didn't completed sucessfully, aborting.", data))
                ret = self.submit_response(action['id'], 255, "Previous run of action didn't completed sucessfully, aborting.", data)
            os.remove(action_lock)
            return ret

        open(action_lock, 'a').close()

        (method, params) = self.__parse_action_data(action)
        (status, message, data) = CheckCli.__run_action(method, params, {'cache_only': cache_only})
        ret = 0
        if not cache_only:
            log.log_debug("Sending back response", (status, message, data))
            ret = self.submit_response(action['id'], status, message, data)
        os.remove(action_lock)
        return ret


    def is_valid_action(self, action):
        log.log_debug("check_action", action)

        # be very paranoid of what we get back
        if type(action) != type({}):
            print("Got unparseable action response from server")
            sys.exit(-1)

        for key in ['id', 'version', 'action']:
            if not key in action:
                print("Got invalid response - missing '%s'" % key)
                sys.exit(-1)
        try:
            ver = int(action['version'])
        except ValueError:
            ver = -1
        if ver > ACTION_VERSION or ver < 0:
            print("Got unknown action version %d" % ver)
            print(action)
            # the -99 here is kind of magic
            self.submit_response(action["id"],
                            xmlrpclib.Fault(-99, "Can not handle this version"))
            return False
        return True

    @staticmethod
    def __get_server():
        """ Initialize a server connection and set up capability info. """
        server = rpcServer.getServer()

        # load the new client caps if they exist
        clientCaps.loadLocalCaps()

        headerlist = clientCaps.caps.headerFormat()
        for (headerName, value) in headerlist:
            server.add_header(headerName, value)

        return server

    @staticmethod
    def __update_system_id():
        try:
            up2dateAuth.maybeUpdateVersion()
        except up2dateErrors.CommunicationError:
            print(sys.exc_info()[1])
            sys.exit(1)

    @staticmethod
    def __build_status_report():
        status_report = {}
        status_report["uname"] = list(os.uname())

        if os.access("/proc/uptime", os.R_OK):
            uptime = open("/proc/uptime", "r").read().split()
            try:
                status_report["uptime"] = [int(float(a)) for a in uptime]
            except (TypeError, ValueError):
                status_report["uptime"] = [a[:-3] for a in uptime]
            except:
                pass

        # We need to fit into xmlrpc's integer limits
        if status_report['uptime'][1] > long(2)**31-1:
            status_report['uptime'][1] = -1

        return status_report

    @staticmethod
    def __run_local_actions():
        """
        Hit any actions that we want to always run.

        If we want to run any actions everytime rhnsd runs rhn_check,
        we can add them to the list LOCAL_ACTIONS
        """

        for method_params in LOCAL_ACTIONS:
            method = method_params[0]
            params =  method_params[1]
            (status, message, data) = CheckCli.__run_action(method, params)
            log.log_debug("local action status: ", (status, message, data))

    @staticmethod
    def __do_call(method, params, kwargs={}):
        log.log_debug("do_call ", method, params, kwargs)

        method = getMethod.getMethod(method, "rhn.actions")
        retval = method(*params, **kwargs)

        return retval

    @staticmethod
    def __run_action(method, params, kwargs={}):
        try:
            (status, message, data) = CheckCli.__do_call(method, params, kwargs)
        except getMethod.GetMethodException:
            log.log_debug("Attempt to call an unsupported action ", method,
                params)
            status = 6
            message = "Invalid function call attempted"
            data = {}
        except:
            log.log_exception(*sys.exc_info())
            # The action code failed in some way. let's let the server know.
            status = 6,
            message = "Fatal error in Python code occurred"
            data = {}
        return (status, message, data)

    @staticmethod
    def __check_rhn_disabled():
        """ If we're disabled, go down (almost) quietly. """
        if os.path.exists(DISABLE_FILE):
            print("RHN service is disabled. Check %s" % DISABLE_FILE)
            sys.exit(0)

    @staticmethod
    def __check_has_system_id():
        """ Retrieve the system_id. This is required. """
        if not up2dateAuth.getSystemId():
            print("ERROR: unable to read system id.")
            sys.exit(-1)

    @staticmethod
    def __check_instance_lock():
        lock = None
        try:
            lock = rhnLockfile.Lockfile('/var/run/rhn_check.pid')
        except rhnLockfile.LockfileLockedException:
            sys.stderr.write(sstr(_("Attempting to run more than one instance of rhn_check. Exiting.\n")))
            sys.exit(0)

if __name__ == "__main__":
    cli = CheckCli()
    cli.run()
