(* Title: Pure/General/secure.ML
ID: $Id$
Author: Makarius
Secure critical operations.
*)
signature SECURE =
sig
val set_secure: unit -> unit
val is_secure: unit -> bool
val deny_secure: string -> unit
val use: string -> unit
val use_text: (string -> unit) * (string -> 'a) -> bool -> string -> unit
val commit: unit -> unit
val execute: string -> string
val system: string -> int
end;
structure Secure: SECURE =
struct
(** secure flag **)
val secure = ref false;
fun set_secure () = secure := true;
fun is_secure () = ! secure;
fun deny_secure msg = deny (is_secure ()) msg;
(** critical operations **)
(* ML evaluation *)
fun secure_mltext () = deny_secure "Cannot evaluate ML source in secure mode";
val orig_use = use;
val orig_use_text = use_text;
fun use file = (secure_mltext (); orig_use file);
fun use_text pr verbose txt = (secure_mltext (); orig_use_text pr verbose txt);
(*commit is dynamically bound!*)
fun commit () = orig_use_text Output.ml_output false "commit();";
(* shell commands *)
fun secure_shell () = deny_secure "Cannot execute shell commands in secure mode";
val orig_execute = execute;
val orig_system = system;
fun execute s = (secure_shell (); orig_execute s);
fun system s = (secure_shell (); orig_system s);
end;
val use = Secure.use;
val use_text = Secure.use_text;
val execute = Secure.execute;
val system = Secure.system;