194 lines
6.5 KiB
OCaml
194 lines
6.5 KiB
OCaml
(* (c) 2017 Hannes Mehnert, all rights reserved *)
|
|
|
|
(* the process responsible for event log *)
|
|
|
|
(* communication channel is a single unix domain socket shared between vmmd and
|
|
vmm_log. There are two commands from vmmd to vmm_log, history and data. *)
|
|
|
|
(* internally, a ring buffer for the last N events is preserved in memory
|
|
each new event is directly written to disk! *)
|
|
|
|
open Lwt.Infix
|
|
|
|
let my_version = `AV3
|
|
|
|
let broadcast prefix wire t =
|
|
Lwt_list.fold_left_s (fun t (id, s) ->
|
|
Vmm_lwt.write_wire s wire >|= function
|
|
| Ok () -> t
|
|
| Error `Exception -> Vmm_trie.remove id t)
|
|
t (Vmm_trie.collect prefix t)
|
|
|
|
let write_complete s cs =
|
|
let l = Cstruct.len cs in
|
|
let b = Cstruct.to_bytes cs in
|
|
let rec w off =
|
|
let len = l - off in
|
|
Lwt_unix.write s b off len >>= fun n ->
|
|
if n = len then Lwt.return_unit else w (off + n)
|
|
in
|
|
w 0
|
|
|
|
let read_from_file file =
|
|
Vmm_lwt.read_from_file file >|= fun data ->
|
|
let logs = Vmm_asn.logs_of_disk my_version data in
|
|
List.rev logs
|
|
|
|
let write_to_file file =
|
|
let mvar = Lwt_mvar.create_empty () in
|
|
let rec write_loop ?(retry = true) ?log_entry ?fd () =
|
|
match fd with
|
|
| None when retry ->
|
|
Lwt_unix.openfile file Lwt_unix.[O_APPEND;O_CREAT;O_WRONLY] 0o600 >>= fun fd ->
|
|
write_loop ~retry:false ?log_entry ~fd ()
|
|
| None ->
|
|
Logs.err (fun m -> m "retry is false, exiting") ;
|
|
Lwt.return_unit
|
|
| Some fd ->
|
|
(match log_entry with
|
|
| None -> Lwt_mvar.take mvar
|
|
| Some l -> Lwt.return l) >>= fun log_entry ->
|
|
let data = Vmm_asn.log_to_disk my_version log_entry in
|
|
Lwt.catch
|
|
(fun () -> write_complete fd data >|= fun () -> (true, None, Some fd))
|
|
(fun e ->
|
|
Logs.err (fun m -> m "exception %s while writing" (Printexc.to_string e)) ;
|
|
Vmm_lwt.safe_close fd >|= fun () ->
|
|
(retry, Some log_entry, None)) >>= fun (retry, log_entry, fd) ->
|
|
write_loop ~retry ?log_entry ?fd ()
|
|
in
|
|
mvar, write_loop
|
|
|
|
let send_history s ring id ts =
|
|
let elements =
|
|
match ts with
|
|
| None -> Vmm_ring.read ring
|
|
| Some since -> Vmm_ring.read_history ring since
|
|
in
|
|
let res =
|
|
List.fold_left (fun acc (ts, event) ->
|
|
let sub = Vmm_core.Log.name event in
|
|
if Vmm_core.Name.is_sub ~super:id ~sub
|
|
then (ts, event) :: acc
|
|
else acc)
|
|
[] elements
|
|
in
|
|
(* just need a wrapper in tag = Log.Data, id = reqid *)
|
|
Lwt_list.fold_left_s (fun r (ts, event) ->
|
|
match r with
|
|
| Ok () ->
|
|
let header = Vmm_commands.{ version = my_version ; sequence = 0L ; name = id } in
|
|
Vmm_lwt.write_wire s (header, `Data (`Log_data (ts, event)))
|
|
| Error e -> Lwt.return (Error e))
|
|
(Ok ()) (List.rev res)
|
|
|
|
let tree = ref Vmm_trie.empty
|
|
|
|
let handle_data s mvar ring hdr entry =
|
|
if not (Vmm_commands.version_eq hdr.Vmm_commands.version my_version) then begin
|
|
Logs.warn (fun m -> m "unsupported version") ;
|
|
Lwt.return_unit
|
|
end else begin
|
|
Vmm_lwt.write_wire s (hdr, `Success `Empty) >>= fun _ ->
|
|
Vmm_ring.write ring entry ;
|
|
Lwt_mvar.put mvar entry >>= fun () ->
|
|
let data' = (hdr, `Data (`Log_data entry)) in
|
|
broadcast hdr.Vmm_commands.name data' !tree >|= fun tree' ->
|
|
tree := tree'
|
|
end
|
|
|
|
let read_data mvar ring s =
|
|
let rec loop () =
|
|
Vmm_lwt.read_wire s >>= function
|
|
| Error _ ->
|
|
Logs.err (fun m -> m "error while reading") ;
|
|
Lwt.return_unit
|
|
| Ok (hdr, `Data (`Log_data entry)) ->
|
|
handle_data s mvar ring hdr entry >>= fun () ->
|
|
loop ()
|
|
| Ok wire ->
|
|
Logs.warn (fun m -> m "unexpected wire %a" Vmm_commands.pp_wire wire) ;
|
|
Lwt.return_unit
|
|
in
|
|
loop ()
|
|
|
|
let handle mvar ring s addr () =
|
|
Logs.info (fun m -> m "handling connection from %a" Vmm_lwt.pp_sockaddr addr) ;
|
|
Vmm_lwt.read_wire s >>= begin function
|
|
| Error _ ->
|
|
Logs.err (fun m -> m "error while reading") ;
|
|
Lwt.return_unit
|
|
| Ok (hdr, `Data (`Log_data entry)) ->
|
|
handle_data s mvar ring hdr entry >>= fun () ->
|
|
read_data mvar ring s
|
|
| Ok (hdr, `Command (`Log_cmd lc)) ->
|
|
if not (Vmm_commands.version_eq hdr.Vmm_commands.version my_version) then begin
|
|
Logs.warn (fun m -> m "unsupported version") ;
|
|
Lwt.return_unit
|
|
end else begin
|
|
match lc with
|
|
| `Log_subscribe ts ->
|
|
let tree', ret = Vmm_trie.insert hdr.Vmm_commands.name s !tree in
|
|
tree := tree' ;
|
|
(match ret with
|
|
| None -> Lwt.return_unit
|
|
| Some s' -> Vmm_lwt.safe_close s') >>= fun () ->
|
|
let out = `Success `Empty in
|
|
Vmm_lwt.write_wire s (hdr, out) >>= function
|
|
| Error _ -> Logs.err (fun m -> m "error while sending reply for subscribe") ;
|
|
Lwt.return_unit
|
|
| Ok () ->
|
|
send_history s ring hdr.Vmm_commands.name ts >>= function
|
|
| Error _ -> Logs.err (fun m -> m "error while sending history") ; Lwt.return_unit
|
|
| Ok () ->
|
|
(* command processing is finished, but we leave the socket open
|
|
until read returns (either with a message we ignore or a failure from the closed connection) *)
|
|
Vmm_lwt.read_wire s >|= fun _ -> ()
|
|
end
|
|
| Ok wire ->
|
|
Logs.warn (fun m -> m "ignoring %a" Vmm_commands.pp_wire wire) ;
|
|
Lwt.return_unit
|
|
end >>= fun () ->
|
|
Vmm_lwt.safe_close s
|
|
|
|
let jump _ file sock =
|
|
Sys.(set_signal sigpipe Signal_ignore) ;
|
|
Lwt_main.run
|
|
((Lwt_unix.file_exists sock >>= function
|
|
| true -> Lwt_unix.unlink sock
|
|
| false -> Lwt.return_unit) >>= fun () ->
|
|
let s = Lwt_unix.(socket PF_UNIX SOCK_STREAM 0) in
|
|
Lwt_unix.(bind s (ADDR_UNIX sock)) >>= fun () ->
|
|
Lwt_unix.listen s 1 ;
|
|
let ring = Vmm_ring.create `Startup () in
|
|
read_from_file file >>= fun entries ->
|
|
List.iter (Vmm_ring.write ring) entries ;
|
|
let mvar, writer = write_to_file file in
|
|
let start = Ptime_clock.now (), `Startup in
|
|
Lwt_mvar.put mvar start >>= fun () ->
|
|
Vmm_ring.write ring start ;
|
|
let rec loop () =
|
|
Lwt_unix.accept s >>= fun (cs, addr) ->
|
|
Lwt.async (handle mvar ring cs addr) ;
|
|
loop ()
|
|
in
|
|
Lwt.pick [ loop () ; writer () ]) ;
|
|
`Ok ()
|
|
|
|
open Cmdliner
|
|
open Vmm_cli
|
|
|
|
let socket =
|
|
let doc = "socket to use" in
|
|
Arg.(value & opt string (Vmm_core.socket_path `Log) & info [ "socket" ] ~doc)
|
|
|
|
let file =
|
|
let doc = "File to write the log to" in
|
|
Arg.(value & opt string "/var/log/albatross" & info [ "logfile" ] ~doc)
|
|
|
|
let cmd =
|
|
Term.(ret (const jump $ setup_log $ file $ socket)),
|
|
Term.info "vmm_log" ~version:"%%VERSION_NUM%%"
|
|
|
|
let () = match Term.eval cmd with `Ok () -> exit 0 | _ -> exit 1
|