* - The 'out' descriptor must be opened first
* - As soon as the backend script dies, the connection to the entry is
* closed.
+ * - To avoid user-inflicted pain, all entries are opened at the time
+ * that they are created. Reopening these entries is a little complicated
+ * but nevertheless sound:
+ * * When a script dies, its fd is reopened
+ * * If a script fails to execute, its fd is closed and reopened to
+ * beat a race that can happen when the user closes the connection
+ * before the script can be launched.
*)
open Inotify
open Printf
open Splice
-let backend_prefix = ref ""
-let direct_fifo_table: (string,(string*string) option) Hashtbl.t = Hashtbl.create 1024
+let close_if_open fd = (try (ignore(close fd);) with _ -> ())
+
+
+let direct_fifo_table: (string,(string*string*string*Unix.file_descr) option) Hashtbl.t = Hashtbl.create 1024
+let pidmap: (int,string) Hashtbl.t = Hashtbl.create 1024
let rec list_check lst elt =
match lst with
| [] -> false
| car::cdr -> if (car==elt) then true else list_check cdr elt
+let openentry_int fifoin =
+ let fdin =
+ try openfile fifoin [O_RDONLY;O_NONBLOCK] 0o777 with
+ e->fprintf logfd "Error opening and connecting FIFO: %s,%o\n" fifoin 0o777;flush logfd;raise e
+ in
+ fdin
+
+
+(** Open fifos for a session. SHOULD NOt shutdown vsys if the fifos don't exist *)
+let openentry_in root_dir fqp_in backend_spec =
+ Dirwatcher.mask_watch root_dir;
+ let fd_in = openentry_int fqp_in in
+ Dirwatcher.unmask_watch root_dir [S_Open];
+ let (fqp,slice_name) = backend_spec in
+ Hashtbl.replace direct_fifo_table fqp_in (Some(root_dir,fqp,slice_name,fd_in))
+
+let openentry root_dir fqp backend_spec =
+ let fqp_in = String.concat "." [fqp;"in"] in
+ openentry_in root_dir fqp_in backend_spec
+
+let reopenentry fifoin =
+ let entry = try Hashtbl.find direct_fifo_table fifoin with _ -> None in
+ match entry with
+ | Some(dir, fqp,slice_name,fd) -> close_if_open fd;openentry_in dir fifoin (fqp,slice_name)
+ | None -> ()
+
(* vsys is activated when a client opens an in file *)
-let connect_file mask_events fqp_out =
+let connect_file fqp_in =
(* Do we care about this file? *)
let entry_info = try
- Hashtbl.find direct_fifo_table fqp_out with _ -> None in
+ Hashtbl.find direct_fifo_table fqp_in with _ -> None in
match entry_info with
- | Some(execpath,slice_name) ->
+ | Some(_,execpath,slice_name,fifo_fdin) ->
fprintf logfd "Executing %s for slice %s\n" execpath slice_name;flush logfd;
begin
- let len = String.length fqp_out in
- let fqp = String.sub fqp_out 0 (len-4) in
- mask_events true;
- let fqp_in = String.concat "." [fqp;"in"] in
- let fifo_fdin =
- try openfile fqp_in [O_RDONLY;O_NONBLOCK] 0o777 with
- e->fprintf logfd "Error opening and connecting FIFO: %s\n" fqp_in;flush logfd;raise e
- in
+ let len = String.length fqp_in in
+ let fqp = String.sub fqp_in 0 (len-3) in
+ let fqp_out = String.concat "." [fqp;"out"] in
let fifo_fdout =
try openfile fqp_out [O_WRONLY;O_NONBLOCK] 0o777 with
_->fprintf logfd "%s Output pipe not open, using stdout in place of %s\n" slice_name fqp_out;flush logfd;stdout
in
- try ignore(create_process execpath [|execpath;slice_name|] fifo_fdin fifo_fdout fifo_fdout); with e -> begin fprintf logfd "Error executing service: %s\n" execpath;flush logfd end;
- close fifo_fdin;
- close fifo_fdout;
- mask_events false;
+ ignore(sigprocmask SIG_BLOCK [Sys.sigchld]);
+ (
+ clear_nonblock fifo_fdin;
+ let pid=try Some(create_process execpath [|execpath;slice_name|] fifo_fdin fifo_fdout fifo_fdout) with e -> None in
+ match pid with
+ | Some(pid) ->Hashtbl.add pidmap pid fqp_in
+ | None ->fprintf logfd "Error executing service: %s\n" execpath;flush logfd;reopenentry fqp_in
+ );
+ ignore(sigprocmask SIG_UNBLOCK [Sys.sigchld]);
end
| None -> ()
with
e->fprintf logfd "Error creating FIFO: %s->%s. May be something wrong at the frontend.\n" fqp fifoout;flush logfd;Failed)
-(** Open fifos for a session. SHOULD NOt shutdown vsys if the fifos don't exist *)
-let openentry fqp backend_spec =
- let fqp_in = String.concat "." [fqp;"out"] in
- Hashtbl.replace direct_fifo_table fqp_in (Some(backend_spec))
(** Close fifos that just got removed *)
let closeentry fqp =
- let fqp_in = String.concat "." [fqp;"out"] in
- Hashtbl.remove direct_fifo_table fqp_in
+ let fqp_in = String.concat "." [fqp;"in"] in
+ let entry = try Hashtbl.find direct_fifo_table fqp_in with Not_found -> None in
+ match entry with
+ | None -> ()
+ | Some(_,_,_,fd) ->
+ close_if_open fd;
+ Hashtbl.remove direct_fifo_table fqp_in
-let direct_fifo_handler wd dirname evlist fname =
- let mask_events flag =
- if (flag) then Dirwatcher.mask_events wd else Dirwatcher.unmask_events wd
- in
- let is_event = list_check evlist in
- if (is_event Open) then
- let fqp_out = String.concat "/" [dirname;fname] in
- connect_file mask_events fqp_out
+let sigchld_handle s =
+ let pid,_=Unix.waitpid [Unix.WNOHANG] 0 in
+ try
+ let fqp_in = Hashtbl.find pidmap pid in
+ printf "Reopening fifo\n";flush Pervasives.stdout;
+ reopenentry fqp_in
+ with _ -> ()
-let add_dir_watch fqp =
+let rec add_dir_watch fqp =
Dirwatcher.add_watch fqp [S_Open] direct_fifo_handler
+and
+direct_fifo_handler wd dirname evlist fname =
+ let is_event = list_check evlist in
+ if (is_event Open) then
+ let fqp_in = String.concat "/" [dirname;fname] in
+ begin
+ connect_file fqp_in;
+ add_dir_watch dirname
+ end
let del_dir_watch fqp =
(* XXX Dirwatcher.del_watch fqp *)
()
+
+let initialize () =
+ Sys.set_signal Sys.sigchld (Sys.Signal_handle sigchld_handle)
git://git.onelab.eu / vsys.git / blobdiff