options of "chcon"

[张京]

Hi!
If anyone can tell me the options of "chcon" in seandroid? I'd like to use
"-R" for a recursively modification, but it doesn't work. And the "--help"
doesn't give any options that is available for "chcon".
    In addition, can anyone tell me how to make a third-party app unable to
be uninstalled via policy configuration?
    Thank you very much!!!