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open Unix
open Proto
open Util
let dbg_out = ref false
let dbg x = if !dbg_out then Format.eprintf "(srv) %s@." x
let dbg1 a x = if !dbg_out then Format.eprintf "(srv) %s %s@." (id_str a) x
let dbg2 a b x = if !dbg_out then Format.eprintf "(srv) %s %s %s@." (id_str a) (id_str b) x
(* Server data structures *)
type task_el =
| Task of task_descr * bool
| MsgTask of string * msg_task_descr
type client_status =
| Waiting
| Busy
type client = {
id: id;
input: file_descr;
send: message -> unit;
disconnect: unit -> unit;
mutable status: client_status;
}
type server = {
tasks: task_el Queue.t;
tsk_chan: (id, msg_task_descr) Hashtbl.t;
msg_chan: (id, string Queue.t) Hashtbl.t;
mutable final_result: string option;
clients: (id, client) Hashtbl.t;
}
let new_server () =
{ tasks = Queue.create ();
tsk_chan = Hashtbl.create 12;
msg_chan = Hashtbl.create 12;
final_result = None;
clients = Hashtbl.create 4;
}
let push_task server task =
let cli = ref None in
Hashtbl.iter
(fun _ c -> if c.status = Waiting then cli := Some c)
server.clients;
match !cli with
| None -> Queue.push task server.tasks
| Some c ->
c.status <- Busy;
c.send
(match task with
| MsgTask(a, b) -> GiveMsgTask(a, b)
| Task(a, b) -> GiveTask(a, b))
let get_task server =
Queue.pop server.tasks
let handle_put server chan msg =
if Hashtbl.mem server.tsk_chan chan then
let task = Hashtbl.find server.tsk_chan chan in
Hashtbl.remove server.tsk_chan chan;
push_task server (MsgTask(msg, task))
else
let chq =
if Hashtbl.mem server.msg_chan chan then
Hashtbl.find server.msg_chan chan
else
let q = Queue.create () in
Hashtbl.add server.msg_chan chan q;
q
in
Queue.push msg chq
let handle_get server chan task =
if Hashtbl.mem server.msg_chan chan &&
(let q = Hashtbl.find server.msg_chan chan in not (Queue.is_empty q))
then
let msg = Queue.pop (Hashtbl.find server.msg_chan chan) in
push_task server (MsgTask(msg, task))
else
if Hashtbl.mem server.tsk_chan chan then
raise (ProtocolError "Several listeners on same channel.")
else
Hashtbl.add server.tsk_chan chan task
let server_add_client server cli =
(* Say hello *)
let msg = read_one_msg cli.input in
if msg <> Hello then raise (ProtocolError "Client must say Hello first thing.");
cli.send Hello;
(* Put client on queue *)
Hashtbl.add server.clients cli.id cli
let client_of_fd server fd =
let cli = ref None in
Hashtbl.iter (fun _ c -> if c.input = fd then cli := Some c) server.clients;
match !cli with
| None -> assert false
| Some c -> c
let rec server_run server =
let fds = Hashtbl.fold
(fun _ c l ->
if c.status = Busy
then c.input::l
else l)
server.clients [] in
if not (fds = []) then begin
dbg "selecting...";
let qi, _, qe = select fds [] fds (-1.0) in
begin match qi, qe with
| x::_, _ ->
let cli = client_of_fd server x in
dbg1 cli.id "reading...";
begin match read_one_msg cli.input with
| RequestTask ->
dbg "got task request";
begin match server.final_result with
| None ->
if Queue.is_empty server.tasks then
cli.status <- Waiting
else cli.send (match Queue.pop server.tasks with
| MsgTask(a, b) -> GiveMsgTask(a, b)
| Task(a, b) -> GiveTask(a,b))
| Some r ->
cli.send(FinalResult r);
cli.disconnect();
Hashtbl.remove server.clients cli.id
end;
| Get(chan, td) ->
dbg2 cli.id chan "got GET";
handle_get server chan td
| Put(chan, msg) ->
dbg2 cli.id chan "got PUT";
handle_put server chan msg
| FinalResult x ->
dbg "got FinalResult";
cli.status <- Waiting;
server.final_result <- Some x;
let p = ref [] in
Hashtbl.iter
(fun _ c -> if c.status = Waiting then p := c::(!p))
server.clients;
List.iter
(fun c ->
c.send(FinalResult x);
c.disconnect();
Hashtbl.remove server.clients c.id)
!p
| GiveTask(a, b) ->
dbg "got Task";
push_task server (Task(a, b))
| GiveMsgTask(a, b) ->
dbg "got MsgTask";
push_task server (MsgTask(a, b))
| Hello -> raise (ProtocolError "Unexpected Hello.")
end
| [], x::_ ->
let cli = client_of_fd server x in
cli.disconnect();
Hashtbl.remove server.clients cli.id
| _ -> assert false
end;
server_run server
end else begin
if server.final_result = None then begin
Format.eprintf "Queue empty: %s@." (if Queue.is_empty server.tasks then "yes" else "no");
Format.eprintf "Client count: %d@." (Hashtbl.length server.clients);
raise (ProtocolError "Everybody waiting but nothing to do.")
end
end
(* Main function *)
let program = ref ""
let local_proc = ref 1
let parse_args () =
let usage = "Usage: ./manager [options] program" in
let options = [
"-dbg", Arg.Set dbg_out, "Show debug output";
"-local-proc", Arg.Set_int local_proc, "Set number of local processes. Default: 1";
] in
Arg.parse options (fun n -> program := n) usage
let () =
Random.self_init();
parse_args();
if !local_proc < 1 then begin
Format.eprintf "Error: at least one local process must be launched !@.";
exit 0;
end;
if !program = "" then begin
Format.eprintf "Error: no program specified!@.";
exit 0
end;
let server = new_server () in
let pids = ref [] in
for i = 0 to !local_proc - 1 do
(* Create file descriptors *)
let m2p_p, m2p_m = pipe () in
let p2m_m, p2m_p = pipe () in
match fork() with
| 0 ->
close m2p_m;
close p2m_m;
dup2 m2p_p stdin;
dup2 p2m_p stdout;
let args = Array.of_list
([!program] @
(if i = 0 then ["-org"] else []) @
(if !dbg_out then ["-dbg"] else [])) in
execv !program args
| pid ->
close m2p_p;
close p2m_p;
let outc = Unix.out_channel_of_descr m2p_m in
server_add_client server
{ id = new_id();
input = p2m_m;
send = (fun msg -> Marshal.to_channel outc msg []; flush outc);
disconnect = (fun () -> close p2m_m; close m2p_m);
status = Busy;
};
pids := pid :: (!pids)
done;
server_run server;
List.iter (fun pid -> ignore (waitpid [] pid)) !pids
|