/**
* Runs Runnable r with a security policy that permits precisely the specified permissions. If
* there is no current security manager, the runnable is run twice, both with and without a
* security manager. We require that any security manager permit getPolicy/setPolicy.
*/
public void runWithPermissions(Runnable r, Permission... permissions) {
SecurityManager sm = System.getSecurityManager();
if (sm == null) {
r.run();
Policy savedPolicy = Policy.getPolicy();
try {
Policy.setPolicy(permissivePolicy());
System.setSecurityManager(new SecurityManager());
runWithPermissions(r, permissions);
} finally {
System.setSecurityManager(null);
Policy.setPolicy(savedPolicy);
}
} else {
Policy savedPolicy = Policy.getPolicy();
AdjustablePolicy policy = new AdjustablePolicy(permissions);
Policy.setPolicy(policy);
try {
r.run();
} finally {
policy.addPermission(new SecurityPermission("setPolicy"));
Policy.setPolicy(savedPolicy);
}
}
}
