Proper handling of Apache log file deletion while Apache might have that file open

[hcoop/domtool2.git] / src / msg.sml

(* HCoop Domtool (http://hcoop.sourceforge.net/)
 * Copyright (c) 2006, Adam Chlipala
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 *)

(* Network messages *)

structure Msg :> MSG = struct

open OpenSSL MsgTypes Slave

val a2i = fn Add => 0
	   | Delete => 1
	   | Modify => 2

val i2a = fn 0 => Add
	   | 1 => Delete
	   | 2 => Modify
	   | _ => raise OpenSSL.OpenSSL "Bad action number to deserialize"

fun sendAcl (bio, {user, class, value}) =
    (OpenSSL.writeString (bio, user);
     OpenSSL.writeString (bio, class);
     OpenSSL.writeString (bio, value))

fun recvAcl bio =
    case (OpenSSL.readString bio, OpenSSL.readString bio, OpenSSL.readString bio) of
	(SOME user, SOME class, SOME value) => SOME {user = user, class = class, value = value}
      | _ => NONE

fun sendList f (bio, ls) =
    (app (fn x =>
	     (OpenSSL.writeInt (bio, 1);
	      f (bio, x))) ls;
     OpenSSL.writeInt (bio, 0))

fun recvList f bio =
    let
	fun loop ls =
	    case OpenSSL.readInt bio of
		SOME 0 => SOME (rev ls)
	      | SOME 1 =>
		(case f bio of
		     SOME x => loop (x :: ls)
		   | NONE => NONE)
	      | _ => NONE
    in
	loop []
    end

fun send (bio, m) =
    case m of
	MsgOk => OpenSSL.writeInt (bio, 1)
      | MsgError s => (OpenSSL.writeInt (bio, 2);
		       OpenSSL.writeString (bio, s))
      | MsgConfig s => (OpenSSL.writeInt (bio, 3);
		       OpenSSL.writeString (bio, s))
      | MsgFile {action, domain, dir, file} =>
	(OpenSSL.writeInt (bio, 4);
	 OpenSSL.writeInt (bio, a2i action);
	 OpenSSL.writeString (bio, domain);
	 OpenSSL.writeString (bio, dir);
	 OpenSSL.writeString (bio, file))
      | MsgDoFiles => OpenSSL.writeInt (bio, 5)
      | MsgGrant acl => (OpenSSL.writeInt (bio, 6);
			 sendAcl (bio, acl))
      | MsgRevoke acl => (OpenSSL.writeInt (bio, 7);
			  sendAcl (bio, acl))
      | MsgListPerms user => (OpenSSL.writeInt (bio, 8);
			      OpenSSL.writeString (bio, user))
      | MsgPerms classes => (OpenSSL.writeInt (bio, 9);
			     sendList (fn (bio, (class, values)) =>
					  (OpenSSL.writeString (bio, class);
					   sendList OpenSSL.writeString (bio, values)))
				      (bio, classes))
      | MsgWhoHas {class, value} => (OpenSSL.writeInt (bio, 10);
				     OpenSSL.writeString (bio, class);
				     OpenSSL.writeString (bio, value))
      | MsgWhoHasResponse users => (OpenSSL.writeInt (bio, 11);
				    sendList OpenSSL.writeString (bio, users))
      | MsgMultiConfig codes => (OpenSSL.writeInt (bio, 12);
				 sendList OpenSSL.writeString (bio, codes))
      | MsgRmdom dom => (OpenSSL.writeInt (bio, 13);
			 OpenSSL.writeString (bio, dom))

fun checkIt v =
    case v of
	NONE => raise OpenSSL.OpenSSL "Bad Msg format"
      | _ => v

fun recv bio =
    case OpenSSL.readInt bio of
	NONE => NONE
      | SOME n =>
	checkIt (case n of
		     1 => SOME MsgOk
		   | 2 => Option.map MsgError (OpenSSL.readString bio)
		   | 3 => Option.map MsgConfig (OpenSSL.readString bio)
		   | 4 => (case (OpenSSL.readInt bio,
				 OpenSSL.readString bio,
				 OpenSSL.readString bio,
				 OpenSSL.readString bio) of
			       (SOME action, SOME domain, SOME dir, SOME file) =>
			       SOME (MsgFile {action = i2a action,
					      domain = domain,
					      dir = dir,
					      file = file})
			     | _ => NONE)
		   | 5 => SOME MsgDoFiles
		   | 6 => (case recvAcl bio of
			       SOME acl => SOME (MsgGrant acl)
			     | _ => NONE)
		   | 7 => (case recvAcl bio of
			       SOME acl => SOME (MsgRevoke acl)
			     | _ => NONE)
		   | 8 => (case OpenSSL.readString bio of
			       SOME user => SOME (MsgListPerms user)
			     | _ => NONE)
		   | 9 => Option.map MsgPerms
				     (recvList (fn bio =>
						   case (OpenSSL.readString bio,
							 recvList OpenSSL.readString bio) of
						       (SOME class, SOME values) => SOME (class, values)
						     | _ => NONE) bio)
		   | 10 => (case (OpenSSL.readString bio, OpenSSL.readString bio) of
				(SOME class, SOME value) => SOME (MsgWhoHas {class = class, value = value})
			      | _ => NONE)
		   | 11 => Option.map MsgWhoHasResponse
			   (recvList OpenSSL.readString bio)
		   | 12 => Option.map MsgMultiConfig
			   (recvList OpenSSL.readString bio)
		   | 13 => Option.map MsgRmdom (OpenSSL.readString bio)
		   | _ => NONE)
	 
end