Fix splice binding (ygrek#51)

Missing Int_val on the offset argument.

CHANGES.txt

@@ -1,3 +1,6 @@
+## v0.4.2 - ???
+* fix splice
+
 ## v0.4.1 - 20 Jun 2022
 * Support OCaml 5 new Unix primitive names
 

src/splice.c

@@ -3,6 +3,7 @@
 #define EXTUNIX_WANT_SPLICE
 #define EXTUNIX_WANT_TEE
 #include "config.h"
+#include "common.h"
 
 #if defined(EXTUNIX_HAVE_SPLICE) | defined(EXTUNIX_HAVE_TEE) | defined(EXTUNIX_HAVE_VMSPLICE)
 static int splice_flags[] =
@@ -15,11 +16,6 @@ static int splice_flags[] =
 #endif
 
 #if defined(EXTUNIX_HAVE_SPLICE)
-static loff_t* get_offset(value v_off)
-{
-  return (Is_long(v_off) ? NULL : &(Field(v_off, 0)));
-}
-
 CAMLprim value caml_extunix_splice(value v_fd_in, value v_off_in, value v_fd_out, value v_off_out, value v_len, value v_flags)
 {
   CAMLparam5(v_fd_in, v_off_in, v_fd_out, v_off_out, v_len);
@@ -28,13 +24,18 @@ CAMLprim value caml_extunix_splice(value v_fd_in, value v_off_in, value v_fd_out
   unsigned int flags = caml_convert_flag_list(v_flags, splice_flags);
   int fd_in = Int_val(v_fd_in);
   int fd_out = Int_val(v_fd_out);
-  loff_t* off_in = get_offset(v_off_in);
-  loff_t* off_out = get_offset(v_off_out);
+  loff_t off_in;
+  loff_t off_out;
+  loff_t* off_in_p = NULL;
+  loff_t* off_out_p = NULL;
   size_t len = Int_val(v_len);
   ssize_t ret;
 
+  if(Is_some(v_off_in)) { off_in = Int_val(Some_val(v_off_in)); off_in_p = &off_in; }
+  if(Is_some(v_off_out)) { off_out = Int_val(Some_val(v_off_out)); off_out_p = &off_out; }
+
   caml_enter_blocking_section();
-  ret = splice(fd_in, off_in, fd_out, off_out, len, flags);
+  ret = splice(fd_in, off_in_p, fd_out, off_out_p, len, flags);
   caml_leave_blocking_section();
 
   if (ret == -1)

test/test.ml

@@ -576,6 +576,28 @@ let test_sysinfo () =
   let (_:int) = t.uptime in
   ()
 
+let test_splice () =
+  require "splice";
+  let pipe_out, pipe_in = Unix.pipe ~cloexec:true () in
+  let name = Filename.temp_file "extunix" "test" in
+  let fd = Unix.openfile name [O_RDWR; O_CREAT; O_CLOEXEC] 0o666 in
+  Unix.ftruncate fd (4096 * 2);
+  assert_equal (Unix.write_substring fd "test0123456789" 0 14) 14;
+  let n = splice fd (Some 4) pipe_in None 10 [] in
+  assert(n = 10);
+  let n = splice pipe_out None fd (Some 4096) 10 [] in
+  assert(n = 10);
+  let b = Bytes.create 13 in
+  let _ = Unix.lseek fd 4096 SEEK_SET in
+  let n = Unix.read fd b 0 13 in
+  assert(n = 13);
+  assert_equal(Bytes.to_string b) "0123456789\000\000\000";
+  Unix.close fd;
+  Unix.unlink name;
+  Unix.close pipe_out;
+  Unix.close pipe_in;
+  ()
+
 let () =
   let wrap test =
     with_unix_error (fun () -> test (); Gc.compact ())
@@ -610,5 +632,6 @@ let () =
     "sockopt" >:: test_sockopt;
     "sendmsg_bin" >:: test_sendmsg_bin;
     "sysinfo" >:: test_sysinfo;
+    "splice" >:: test_splice;
 ]) in
   ignore (run_test_tt_main (test_decorate wrap tests))