os.system("qemu-img create -f qcow2 -b \"%s\" \"%s\"" %
                  (newnames[i], i))
        os.chmod(i, 0o664)
    return 0

def cmd_snapshots(options):
    """ vws snapshots - list existing snapshots """
    if not options.stopped:
        print("Cannot list snapshots of running VW", file=sys.stderr)
        sys.exit(1)
    os.chdir(options.dir)
    drives = get_drives(options.dir)
    lst = []
    info = {}
    with os.popen("qemu-img info --backing-chain " + drives[0], "r") as f:
    with os.popen("qemu-img info -U --backing-chain " + drives[0], "r") as f:
        for line in f:
            if line.find(": ") != -1:
                var, val = line.strip().split(": ")
                if val != "":
                    info[var] = val
            elif line[0] == '\n':
                lst.append(info)

def cmd_commit(options):
    """
    Commits last snapshot changes into it's backing file
    There would be one snapshot less for virtual machine
    """
    if options.stopped:
        #
        # Stoppend vm - last snapshot is commited into its backing file.
        # Stopped vm - last snapshot is commited into its backing file.
        # Backing file is made current drive image
        #
        os.chdir(options.dir)
        found = 0
        for drive in get_drives(options.dir):
            backing = get_backing(drive)
            if backing is None:

    # Parse argument
    args = ArgumentParser(description="Manage Virtual Workstations")
    cmds = args.add_subparsers(dest='command', help="sub-command help")
    p = cmds.add_parser("list", help="List existing VWs",
                        description="List existing VWs")
    p.add_argument("-l", "--state", const=True, default=False, dest='state',
                   action='store_const', help='Show state of the machine')
    p.add_argument("--usb", action='store_const', const=True, default=False,
                   dest='usb', help='Show connected USB devices')
    p.add_argument('-u', "--usb", action='store_const', const=True, 
	               default=False, dest='usb', help='Show connected USB devices')
    p.add_argument("pattern", nargs='*', default='*', help="Name patterns")
    p = cmds.add_parser("version", help="show vws version")
    p = cmds.add_parser("autostart",
                        help="Autostart all VMs marked as autostartable")
    p = cmds.add_parser("shutdown", help="shut down all running VMs")
    p.add_argument('-w', "--wait", 
    p.add_argument("--wait", help="wait until all machines would be shoutdown",
                   help="wait until all machines would be shutdown",
                   action="store_const", const=True, default=False, dest="wait")
    p.add_argument("--timeout", type=int, default=90,
    p.add_argument('-t', "--timeout", type=int, default=90,
                   help="how long to way for VMs shutdown before forcing it off")
    # Power management
    p = new_command(cmds, 'start', help='Start VW and connect to console',
                    description="Start VW if not running and connect " +
                    "to the console")
    p.add_argument('--no-gui', dest='gui', action='store_const', const=False,
                   default=True, help='do not open console window')

    p.add_argument('snapname', help='snapshot name')
    p = new_command(cmds, 'revert', help='Revert to snapshot')
    p.add_argument('snapname', help='name of snapshot to revert to')
    p = new_command(cmds, 'commit',
                    help='Commit snapshot changes into backing file')
    p = new_command(cmds, 'snapshots', help='List existing snapshots')
    # Screenshoits and recording
    p = new_command(cmds, 'screenshot', help='take a screenshot')
    p.add_argument('filename', help='PPM image filename to write screenshot to')
    p = new_command(cmds, 'screenshot', help='take a screenshot',
                    description='Takes a screenshot',
                    epilog="""Writes current screen contents of the virtual machine into PPM format file""")
    p.add_argument('filename', metavar='filename.ppm',
	               help='PPM image filename to write screenshot to')
    p = new_command(cmds, 'record', help='Record audio output from VM')
    p.add_argument('filename', help='wav file to record autdio to')
    new_command(cmds, 'stoprecord', help='stop recording audio')
    p = new_command(cmds, 'sendkey', help='Send a keystroke to VM')
    p = new_command(cmds, 'sendkey', help='Send a keystroke to VM',
                    description='Send a key combination into VM',
                    epilog='Each key combination should be passed as separate' +
                    'argument.\nAll non-alphanumeric keys should be passed by' +
                    'names, not characters\n(see table in the manual).'
                    )
    p.add_argument('keyspec', help='key specification like ctrl-alt-delete',
                   nargs='+')
    # Create new VM
    p = new_command(cmds, 'create', help="Create new VW")
    p.add_argument("--no-usb", help="Disable USB controller", action='store_const',
                   const=False, default=True, dest="usb")
    p.add_argument("--size", metavar='size', help="Size of primary disk images",