Introduced direct-connected services, which offer pipe semantics.

[vsys.git] / directfifowatcher.ml

diff --git a/directfifowatcher.ml b/directfifowatcher.ml
new file mode 100644 (file)
index 0000000..3f89ad4
--- /dev/null
+++ b/directfifowatcher.ml
@@ -0,0 +1,90 @@
+(** fifowatcher.ml: Routines to handle non-persistent scripts *)
+
+open Inotify
+open Unix
+open Globals
+open Dirwatcher
+open Printf
+open Splice
+
+let backend_prefix = ref ""
+let direct_fifo_table: (string,(string*string) option) 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
+
+
+
+
+(* vsys is activated when a client opens an in file *)
+let connect_file fqp_in =
+  (* Do we care about this file? *)
+  let entry_info = try
+    Hashtbl.find direct_fifo_table fqp_in with _ -> fprintf logfd "[Alert] Access via unauthorized vsys entry: %s\n" fqp_in;flush logfd;None in
+    match entry_info with
+      | Some(execpath,slice_name) ->
+          fprintf logfd "Executing %s for slice %s\n" execpath slice_name;flush logfd;
+          begin
+            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_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 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 -> fprintf logfd "Error executing service: %s\n" execpath;flush logfd
+          end
+      | None -> ()
+
+
+(** Make a pair of fifo entries *)
+let mkentry fqp abspath perm uname = 
+  fprintf logfd "Making entry %s->%s\n" fqp abspath;flush logfd;
+  let fifoin=sprintf "%s.in" fqp in
+  let fifoout=sprintf "%s.out" fqp in
+    (try Unix.unlink fifoin with _ -> ());
+    (try Unix.unlink fifoout with _ -> ());
+    (try 
+       let infname =(sprintf "%s.in" fqp) in
+       let outfname =(sprintf "%s.out" fqp) in
+         Unix.mkfifo infname 0o666;
+         Unix.mkfifo outfname 0o666;
+         ( (* Make the user the owner of the pipes in a non-chroot environment *)
+           if (!Globals.nochroot) then
+             let pwentry = Unix.getpwnam uname in
+               Unix.chown infname pwentry.pw_uid pwentry.pw_gid; 
+               Unix.chown outfname pwentry.pw_uid pwentry.pw_gid
+         );
+         Success
+     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;"in"] 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;"in"] in
+    Hashtbl.remove direct_fifo_table fqp_in
+
+let direct_fifo_handler dirname evlist fname =
+  printf "Received event %s %s\n" dirname fname;flush Pervasives.stdout;
+  let is_event = list_check evlist in
+    if (is_event Open) then 
+      let fqp_in = String.concat "/" [dirname;fname] in
+        connect_file fqp_in
+
+let add_dir_watch fqp =
+  Dirwatcher.add_watch fqp [S_Open] (Some(direct_fifo_handler))
+
+let del_dir_watch fqp =
+  (* XXX Dirwatcher.del_watch fqp *)
+  ()