From: Sapan Bhatia <sapanb@cs.princeton.edu>
Date: Sun, 2 Mar 2008 20:55:13 +0000 (+0000)
Subject: Splice and tee (continued...)
X-Git-Tag: vsys-0.7-4~25
X-Git-Url: http://git.onelab.eu/?p=vsys.git;a=commitdiff_plain;h=210b03e8a5cfffb3c25ea04a03548a430fd13372

Splice and tee (continued...)
---

diff --git a/fifowatcher.ml b/fifowatcher.ml
index 061d86b..d9625b6 100644
--- a/fifowatcher.ml
+++ b/fifowatcher.ml
@@ -22,7 +22,6 @@ let pidmap: (int,signed_fd list) Hashtbl.t = Hashtbl.create 1024
 let backend_prefix = ref ""
 let open_fds: (Unix.file_descr,channel_pipe) Hashtbl.t = Hashtbl.create 1024
 
-
 (** Receive an event from a running script. This event must be relayed to the
   slice that invoked it.
 
@@ -37,13 +36,19 @@ let receive_process_event (idesc: fname_and_fd) (_: fname_and_fd) =
     match (cp) with 
       | Fifo(fifo_outfd) ->
           begin
-          try
-            printf "Received process event\n";flush Pervasives.stdout;
-            let tr0,tr1 = Unix.pipe () in
-                ignore(splice ifd tr1 4096);
-                ignore(splice tr0 fifo_outfd 4096)
-          with 
-              Failure(s)->fprintf logfd "Transfer failure: %s\n" s;flush logfd
+            try
+              printf "Received process event\n";flush Pervasives.stdout;
+              (* transferred = 4096 => there were at least 4096 bytes in the
+               * stream, so we should try again.
+               * transferred < 4096 => EAGAIN => either this is all the data we
+               * have (move on)
+               * OR XXX the receiver is blocking (supposedly this can't happen) *)
+              let transferred = ref 4096 in
+                while (!transferred == 4096) do 
+                  transferred:=tee ifd fifo_outfd 4096
+                done;
+            with 
+                Failure(s)->fprintf logfd "Transfer failure: %s\n" s;flush logfd
           end
       | _ -> fprintf logfd "Bug! Process fd received in the channel handler\n";flush logfd;raise Bug
 
@@ -110,22 +115,27 @@ and receive_fifo_event eventdescriptor outdescriptor =
 
                   (Process(script_outfd))
   in
-  (* We have the connection to the process - because it was open, or because it
-   just got established *)
+    (* We have the connection to the process - because it was open, or because it
+     just got established *)
     match (pipe) with
       | Process(fifo_outfd) -> 
           begin
-          try
-            printf "Received fifo event\n";flush Pervasives.stdout;
-            let tr0,tr1 = Unix.pipe() in
-          ignore(splice evfd tr1 4096);
-          ignore(splice tr0 fifo_outfd 4096)
-          with Failure(str) ->
-            begin
-            fprintf logfd "Error connecting user to service: %s\n" str;
-            flush logfd
-            end;
-            ignore(sigprocmask SIG_UNBLOCK [Sys.sigchld])
+            try
+              let transferred = ref 4096 in
+                while (!transferred == 4096) do
+                  begin
+                  transferred:=tee evfd fifo_outfd 4096;
+                                 printf "Transferred: %d\n" !transferred;flush Pervasives.stdout
+                  end
+                done;
+            with Failure(str) ->
+              begin
+                fprintf logfd "Error connecting user to service: %s\n" str;
+                flush logfd
+              end;
+              ignore(sigprocmask SIG_UNBLOCK [Sys.sigchld]);
+                                 printf "Out of the loop\n";flush Pervasives.stdout
+
           end
       | BrokenPipe -> ()
       | Fifo(_) -> fprintf logfd "BUG! received process event from fifo\n";raise Bug
@@ -144,10 +154,10 @@ let mkentry fqp abspath perm uname =
          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
+           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 
diff --git a/splice.ml b/splice.ml
index a25d981..3e1dfad 100644
--- a/splice.ml
+++ b/splice.ml
@@ -3,5 +3,5 @@ open Unix
 external splice : Unix.file_descr -> Unix.file_descr -> int -> int
                    = "stub_splice"
 
-external sendfile : Unix.file_descr -> Unix.file_descr -> int -> int
-                   = "stub_sendfile"
+external tee : Unix.file_descr -> Unix.file_descr -> int -> int
+                   = "stub_tee"
diff --git a/splice_stub.c b/splice_stub.c
index a8da686..61fbd56 100644
--- a/splice_stub.c
+++ b/splice_stub.c
@@ -22,8 +22,7 @@ CAMLprim value stub_splice(value fd_in, value fd_out, value len)
         CAMLparam3(fd_in, fd_out, len);
 	long ret;
         ret = syscall(SPLICE_SYSCALL, Int_val(fd_in), NULL, Int_val(fd_out),NULL, Int_val(len), SPLICE_F_NONBLOCK);
-        if (ret == -1) {
-		printf ("Splice error: %s\n", strerror(errno));
+        if (ret == -1 && errno!=EAGAIN) {
                 caml_failwith("Splice system call returned -1");
 	}
         CAMLreturn(Val_int(ret));
@@ -34,9 +33,8 @@ CAMLprim value stub_tee(value fd_in, value fd_out, value len)
         CAMLparam3(fd_in, fd_out, len);
 	long ret;
         ret = syscall(TEE_SYSCALL,Int_val(fd_in), Int_val(fd_out), Int_val(len), SPLICE_F_NONBLOCK);
-        if (ret == -1) {
-		printf ("Sendfile error: %s\n", strerror(errno));
-                caml_failwith("Splice system call returned -1");
+        if (ret == -1 && errno!=EAGAIN) {
+                caml_failwith(strerror(errno));
 	}
         CAMLreturn(Val_int(ret));
 }