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vmmd: revise process, write_reply, and out signatures, move process to jump

This commit is contained in:
Hannes Mehnert 2019-01-20 21:56:32 +01:00
parent d4e31da27f
commit d84013103c
1 changed files with 75 additions and 60 deletions
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135
app/vmmd.ml
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@ -37,20 +37,20 @@ let create process cont =
let state', out' = Vmm_vmmd.handle_shutdown !state name vm r in let state', out' = Vmm_vmmd.handle_shutdown !state name vm r in
state := state' ; state := state' ;
s := { !s with vm_destroyed = succ !s.vm_destroyed } ; s := { !s with vm_destroyed = succ !s.vm_destroyed } ;
(process "handle shutdown" out' >|= fun _ -> ()) >|= fun () -> process "handle shutdown (stat, log)" out' >|= fun () ->
let state', waiter_opt = Vmm_vmmd.waiter !state name in let state', waiter_opt = Vmm_vmmd.waiter !state name in
state := state' ; state := state' ;
(match waiter_opt with (match waiter_opt with
| None -> () | None -> ()
| Some wakeme -> Lwt.wakeup wakeme ())) ; | Some wakeme -> Lwt.wakeup wakeme ())) ;
(process "setting up statistics, log, reply" out >|= fun _ -> ()) process "setting up stat, log, reply" out
let register who header = let register who header =
match Vmm_vmmd.register !state who Lwt.task with match Vmm_vmmd.register !state who Lwt.task with
| None -> Error (`Data (header, `Failure "task already registered")) | None -> Error (`Data (header, `Failure "task already registered"))
| Some (state', task) -> state := state' ; Ok task | Some (state', task) -> state := state' ; Ok task
let handle out fd addr = let handle process fd addr =
Logs.debug (fun m -> m "connection from %a" Vmm_lwt.pp_sockaddr addr) ; Logs.debug (fun m -> m "connection from %a" Vmm_lwt.pp_sockaddr addr) ;
(* now we need to read a packet and handle it (* now we need to read a packet and handle it
(1) (1)
@ -64,21 +64,6 @@ let handle out fd addr =
-- Lwt effects happen (stats, logs, wait_and_clear) -- -- Lwt effects happen (stats, logs, wait_and_clear) --
(2) goto (1) (2) goto (1)
*) *)
let process txt wires =
Lwt_list.fold_left_s (fun r data ->
match r, data with
| Ok (), (#Vmm_vmmd.service_out as o) -> out o
| Ok (), `Data wire ->
(* rather: terminate connection *)
Vmm_lwt.write_wire fd wire >|= fun _ ->
Ok ()
| Error e, _ -> Lwt.return (Error e))
(Ok ()) wires >|= function
| Ok () -> Ok ()
| Error (`Msg msg) ->
Logs.err (fun m -> m "error in processing data %s: %s" txt msg) ;
Error ()
in
let rec loop () = let rec loop () =
Logs.debug (fun m -> m "now reading") ; Logs.debug (fun m -> m "now reading") ;
Vmm_lwt.read_wire fd >>= function Vmm_lwt.read_wire fd >>= function
@ -86,32 +71,31 @@ let handle out fd addr =
Logs.err (fun m -> m "error while reading") ; Logs.err (fun m -> m "error while reading") ;
Lwt.return_unit Lwt.return_unit
| Ok wire -> | Ok wire ->
Logs.debug (fun m -> m "read sth") ; Logs.debug (fun m -> m "read %a" Vmm_commands.pp_wire wire) ;
let state', data, next = Vmm_vmmd.handle_command !state wire in let state', data, next = Vmm_vmmd.handle_command !state wire in
state := state' ; state := state' ;
process "handle_command" data >>= function process "handle command" data >>= fun () ->
| Error () -> Lwt.return_unit match next with
| Ok () -> match next with | `Loop -> loop ()
| `Loop -> loop () | `End -> Lwt.return_unit
| `End -> Lwt.return_unit | `Create cont -> create process cont
| `Create cont -> create process cont | `Wait (who, out) ->
| `Wait (who, out) -> (match register who (fst wire) with
(match register who (fst wire) with | Error out' -> process "wait" [ out' ]
| Error out' -> process "wait" [ out' ] >|= ignore | Ok task ->
| Ok task -> task >>= fun () ->
task >>= fun () -> process "wait" [ out ])
process "wait" [ out ] >|= ignore) | `Wait_and_create (who, next) ->
| `Wait_and_create (who, next) -> (match register who (fst wire) with
(match register who (fst wire) with | Error out' -> process "wait and create" [ out' ]
| Error out' -> process "wait and create" [ out' ] >|= ignore | Ok task ->
| Ok task -> task >>= fun () ->
task >>= fun () -> let state', data, n = next !state in
let state', data, n = next !state in state := state' ;
state := state' ; process "wait and create" data >>= fun () ->
process "wait and create" data >>= fun _ -> match n with
match n with | `End -> Lwt.return_unit
| `End -> Lwt.return_unit | `Create cont -> create process cont)
| `Create cont -> create process cont >|= ignore)
in in
loop () >>= fun () -> loop () >>= fun () ->
Vmm_lwt.safe_close fd Vmm_lwt.safe_close fd
@ -185,39 +169,70 @@ let jump _ =
| Some c -> c) >>= fun (c, c_fd, c_mut) -> | Some c -> c) >>= fun (c, c_fd, c_mut) ->
create_mbox `Stats >>= fun s -> create_mbox `Stats >>= fun s ->
let write_reply (header, cmd) name mvar fd mut = let write_reply txt (header, cmd) name mvar fd mut =
Lwt_mutex.with_lock mut (fun () -> Lwt_mutex.with_lock mut (fun () ->
Lwt_mvar.put mvar (header, cmd) >>= fun () -> Lwt_mvar.put mvar (header, cmd) >>= fun () ->
Vmm_lwt.read_wire fd) >|= function Vmm_lwt.read_wire fd) >|= function
| Ok (header', reply) -> | Ok (header', reply) ->
if not Vmm_commands.(version_eq header.version header'.version) then if not Vmm_commands.(version_eq header.version header'.version) then begin
Error (`Msg ("wrong version in reply from " ^ name)) Logs.err (fun m -> m "%s: wrong version (got %a, expected %a) in reply from %s"
else if not Vmm_commands.(Int64.equal header.sequence header'.sequence) then txt
Error (`Msg ( Vmm_commands.pp_version header'.Vmm_commands.version
Fmt.strf "wrong id %Lu (expected %Lu) in reply from %s" Vmm_commands.pp_version header.Vmm_commands.version
header'.Vmm_commands.sequence header.Vmm_commands.sequence name)) name) ;
else begin match reply with invalid_arg "bad version received"
| `Success _ -> Ok () end else if not Vmm_commands.(Int64.equal header.sequence header'.sequence) then begin
| `Failure msg -> Error (`Msg (msg ^ " from " ^ name)) Logs.err (fun m -> m "%s: wrong id %Lu (expected %Lu) in reply from %s"
| _ -> Error (`Msg ("unexpected data from " ^ name)) txt header'.Vmm_commands.sequence header.Vmm_commands.sequence name) ;
invalid_arg "wrong sequence number received"
end else begin
Logs.debug (fun m -> m "%s: received valid reply from %s %a"
txt name Vmm_commands.pp_wire (header', reply)) ;
match reply with
| `Success _ -> ()
| `Failure msg ->
(* can we programatically solve such a situation? *)
(* we at least know e.g when writing to console resulted in an error,
that we can't continue but need to roll back -- and not continue
with execvp() *)
Logs.err (fun m -> m "%s: received failure %s from %s" txt msg name)
| _ ->
Logs.err (fun m -> m "%s: unexpected data from %s" txt name) ;
invalid_arg "unexpected data"
end end
| Error _ -> Error (`Msg ("error in read from " ^ name)) | Error _ ->
Logs.err (fun m -> m "error in read from %s" name) ;
invalid_arg "communication failure"
in in
let out = function let out txt = function
| `Stat wire -> | `Stat wire ->
begin match s with begin match s with
| None -> Lwt.return (Ok ()) | None -> Lwt.return_unit
| Some (s, s_fd, s_mut) -> write_reply wire "stats" s s_fd s_mut | Some (s, s_fd, s_mut) -> write_reply txt wire "stats" s s_fd s_mut
end end
| `Log wire -> write_reply wire "log" l l_fd l_mut | `Log wire -> write_reply txt wire "log" l l_fd l_mut
| `Cons wire -> write_reply wire "console" c c_fd c_mut | `Cons wire -> write_reply txt wire "console" c c_fd c_mut
in in
let process ?fd txt wires =
Lwt_list.iter_p (function
| (#Vmm_vmmd.service_out as o) -> out txt o
| `Data wire -> match fd with
| None ->
Logs.app (fun m -> m "%s received %a" txt Vmm_commands.pp_wire wire) ;
Lwt.return_unit
| Some fd ->
(* TODO should we terminate the connection on write failure? *)
Vmm_lwt.write_wire fd wire >|= fun _ ->
())
wires
in
Lwt.async stats_loop ; Lwt.async stats_loop ;
Lwt.catch (fun () -> Lwt.catch (fun () ->
let rec loop () = let rec loop () =
Lwt_unix.accept ss >>= fun (fd, addr) -> Lwt_unix.accept ss >>= fun (fd, addr) ->
Lwt_unix.set_close_on_exec fd ; Lwt_unix.set_close_on_exec fd ;
Lwt.async (fun () -> handle out fd addr) ; Lwt.async (fun () -> handle (process ~fd) fd addr) ;
loop () loop ()
in in
loop ()) loop ())