#
# Marta Carbone - UniPi
# $Id$
#
# This class requires the rpm package containing
# the picobsd image to be installed
# on the Central Site system.
#

import base64
import os
import datetime

from PLC.Faults import *                          # faults library
from PLC.Method import Method                     # base class for methods
from PLC.Parameter import Parameter               # use the Parameter wrapper
from PLC.Auth import Auth                         # import the Auth parameter
from PLC.Nodes import *                           # nodes functions
from PLC.Methods.GetBootMedium import compute_key # key generation function
from PLC.Accessors.Accessors_dummynetbox import *                       # import dummynet accessors

WORK_DIR = "/var/tmp/DummynetBoxMedium"
BASE_IMAGE = "/usr/share/dummynet/picobsd"

class GetDummyBoxMedium(Method):
    """
    This method is used to get a boot image of the DummyNetBox
    equipped with the configuration file.

    We need to provide the dummybox_id of the DummyNetBox
    we want to generate.
    Since every time a new configuration file will be generater,
    THIS OPERATION WILL INVALIDATE ANY PREVIOUSLY DUMMYNETBOX BOOT MEDIUM.
    # XXX add checks for picobsd.bin existence

    Returns the iso image customized for the DummyNetBox with the new
    key integrated in the image, and update the key fields in the database.
    """
    # I added the session role, because this method should be called from the web
    roles = ['admin', 'pi', 'tech', 'session']

    accepts = [
        Auth(),
        Parameter(int, "The dummybox_id"),
        Parameter(str, "The image type (bin or iso)")
    ]

    returns = Parameter(str, "DummynetBox boot medium")

    # Generate a new configuration file in the working directory
    # input parameters follows:
    # self is used to access instance data,
    # dummybox is the dummybox_id,
    # new_key is the new generated key,
    # configfile is the output file of the configuration.
    def generate_conf_file(self, dummybox, new_key, configfile):
	
        # Generate the dummynet box configuration file
        today = datetime.date.today()
        file = ""
        file += "# This is the dummynetbox configuration file\n"
        file += "# and was generated the %s\n" % str(today)
        
        host_domain = dummybox['hostname']
        host_domain = host_domain.split('.', 1)
        file += 'HOST_NAME="%s"\n' % host_domain[0]
        file += 'DOMAIN_NAME="%s"\n' % host_domain[1]
        
        file += 'IP_ADDRESS="%s"\n' % dummybox['ip']
        file += 'IP_NETMASK="%s"\n' % dummybox['netmask']
        file += 'IP_GATEWAY="%s"\n' % dummybox['gateway']
        file += 'IP_DNS1="%s"\n' % dummybox['dns1']
        file += 'IP_DNS2="%s"\n' % dummybox['dns2']
        file += 'DUMMYBOX_ID="%s"\n' % dummybox['node_id']
        file += 'DUMMYBOX_KEY="%s"\n' % new_key
        
        file += 'CS_IP="%s"\n' % self.api.config.PLC_API_HOST

        # write the configuration file
        # WORK_DIR must be writable
        FILE = open(configfile, "w")
        FILE.write(file)
        FILE.close()
        
        return
        
    # Here starts the execution of the call
    def call(self, auth, dummybox_id, type):

        # check for dummynet box existence and get dummyboxes information
        dummybox_info = Nodes(self.api, {'node_id':dummybox_id, 'node_type':'dummynet'}, \
                ['hostname', 'interface_ids'])
 
        if dummybox_id != None and not dummybox_info:
            raise PLCInvalidArgument, "No such DummyBox %s" % dummybox_id

        # Get the dummynet box hostname
        dummybox_hostname = dummybox_info[0]['hostname']
	print "dummybox hostname %s" % dummybox_hostname

        # get the node interface, if configured
        interfaces = Interfaces(self.api, dummybox_info[0]['interface_ids'])
        for i in interfaces:
            if i['is_primary']:
                interface_info = i
                break

        if not interface_info:
            raise PLCInvalidArgument, "No primary network configured on %s" % dummybox_hostname

	dummybox = interface_info

	# Select the base image, default to bin image
        if type != 'iso':
                type="bin"
        IMAGE_NAME = str(WORK_DIR) + "/dummybox_" + dummybox_hostname + str(type)
        BASE_IMAGE = "/usr/share/dummynet/picobsd." + str(type)
        configfile = WORK_DIR + '/dummybox.conf'
        lockfile =  WORK_DIR + '/lockfile'

        # Permission checks
        assert self.caller is not None
        if 'admin' not in self.caller['roles']:
            if dummybox['site_id'] not in self.caller['site_ids']:
                raise PLCPermissionDenied, "Not allowed to generate an iso image for %s %s" % \
                               (dummybox['hostname'], dummybox_id)

        # Start the generation of the image
        # Generate a new key
        new_key = compute_key()

        # create working dir and lock file for concurrent runs
        if not os.path.exists(WORK_DIR):
            print "Creating working directory %s" % WORK_DIR
            os.mkdir(WORK_DIR)

        if os.path.exists(lockfile):
            raise PLCInvalidArgument, "Lockfile %s exist, try again " % lockfile
        else:
            print "Executing "+"touch %s" % lockfile
            os.system("touch %s" % lockfile)

        # generate the configuration file
        conf_file = self.generate_conf_file(dummybox, new_key, configfile)

        # build the shell script to customize the dummynetbox image
        # copy the raw file and find the configuration file position
        shell_script = "(cp %s %s; export MATCH=`grep -abo START_USER_DATA %s | cut -d: -f1`; " \
                           % (BASE_IMAGE, IMAGE_NAME, IMAGE_NAME)

	# set permission file
	shell_script += " chmod u+w %s; chmod u+w %s; " % (IMAGE_NAME, configfile)

        # cat the configuration file in the raw image
        shell_script += "cat %s | dd of=%s seek=$MATCH conv=notrunc bs=1)" \
                           % (configfile, IMAGE_NAME)

        # check returned values, 0 means OK, remove the lock file
        os.system(shell_script)
        os.system("rm %s" % (lockfile))

        # if all goes fine store the key in the database
        dummybox['key'] = new_key
        dummybox.sync()

        # return the file
        return IMAGE_NAME
        return base64.b64encode(file(IMAGE_NAME).read())