NePA TesT: Community Network Emulator

"Module dependency utility functions for Mininet."

from mininet.util import quietRun

from mininet.log import info, error, debug

from os import environ

def lsmod():

    "Return output of lsmod."

    return quietRun( 'lsmod' )

def rmmod( mod ):

    """Return output of lsmod.

       mod: module string"""

    return quietRun( [ 'rmmod', mod ] )

def modprobe( mod ):

    """Return output of modprobe

       mod: module string"""

    return quietRun( [ 'modprobe', mod ] )

OF_KMOD = 'ofdatapath'

OVS_KMOD = 'openvswitch_mod'

TUN = 'tun'

def moduleDeps( subtract=None, add=None ):

    """Handle module dependencies.

       subtract: string or list of module names to remove, if already loaded

       add: string or list of module names to add, if not already loaded"""

    subtract = subtract if subtract is not None else []

    add = add if add is not None else []

    if type( subtract ) is str:

        subtract = [ subtract ]

    if type( add ) is str:

        add = [ add ]

    for mod in subtract:

        if mod in lsmod():

            info( '*** Removing ' + mod + '\n' )

            rmmodOutput = rmmod( mod )

            if rmmodOutput:

                error( 'Error removing ' + mod + '\n%s' % rmmodOutput )

                exit( 1 )

            if mod in lsmod():

                error( 'Failed to remove ' + mod + '; still there!\n' )

                exit( 1 )

    for mod in add:

        if mod not in lsmod():

            info( '*** Loading ' + mod + '\n' )

            modprobeOutput = modprobe( mod )

            if modprobeOutput:

                error( 'Error inserting ' + mod + ';\n See INSTALL.\n%s' %

                       modprobeOutput )

                exit( 1 )

            if mod not in lsmod():

                error( 'Failed to insert ' + mod + '\n' )

                exit( 1 )

        else:

            debug( '*** ' + mod + ' already loaded\n' )

def pathCheck( *args ):

    "Make sure each program in *args can be found in $PATH."

    for arg in args:

        if not quietRun( 'which ' + arg ):

            error( 'Cannot find required executable %s -'

                ' is it installed somewhere in your $PATH?\n(%s)\n' %

                    ( arg, environ[ 'PATH' ] ) )

            exit( 1 )