0005289: error code 141 / "unknown C primitive `unix_dup'" when flushing to unopened pipe - MantisBT

Mantis Bug Tracker

View Issue Details [ Jump to Notes ]

[ Issue History ] [ Print ]

ID

Project

Category

View Status

Date Submitted

Last Update

0005289

OCaml

OCaml general

public

2011-06-15 21:57

2011-08-03 18:00

Reporter

cvp

Assigned To

Priority

normal

Severity

crash

Reproducibility

always

Status

resolved

Resolution

no change required

Platform

GNU/Linux (x86_64)

OS

Fedora Core (x86_64)

OS Version

15

Product Version

3.12.0

Target Version

Fixed in Version

Summary

0005289: error code 141 / "unknown C primitive `unix_dup'" when flushing to unopened pipe

Description

When piping to programs that don't use stdin, the toplevel and the bytecode interpreter straight-up crash, when you would expect that an exception be thrown instead or something.

Steps To Reproduce

Toplevel:
$ ocaml
# #load "unix.cma" ;;
# let p_out = Unix.open_process_out "true" ;;
val p_out : out_channel = <abstr>
# output_string p_out "foo" ;;
- : unit = ()
# flush p_out ;; (* crashes *)
$ echo $?
141
$

(Also crashes in toplevel without dynamic loading, made with:
$ ocamlmktop -custom -cclib -lunix unix.cma -o unix-top
)

Bytecode:
$ cat > fail.ml
let p_out = Unix.open_process_out "true" in
  output_string p_out "foo";
  flush p_out;
  close_out p_out;
  Unix.close_process_out p_out ;;
print_endline "executed successfully" ;;
^D
$ ocamlc -custom -cclib -lunix unix.cma fail.ml -o fail
$ ./fail # works
executed successfully
$ ocamlrun fail # doesn't
Fatal error: unknown C primitive `unix_dup'
$

Compiling to native machine code produces no errors (i.e. "executed successfully").

Additional Information

$ uname -a
Linux icarus 2.6.38.7-30.fc15.x86_64 #1 SMP Fri May 27 05:15:53 UTC 2011 x86_64 x86_64 x86_64 GNU/Linux

$ ocaml -version
The Objective Caml toplevel, version 3.12.0

$ grep '$Id' $(ocamlc -where)/unix.mli
(* $Id: unix.mli 10450 2010-05-21 12:00:49Z doligez $ *)

Tags

No tags attached.

Relationships

Notes
(0006011) cvp (reporter) 2011-06-15 21:58	Er... click the "View Advanced" link to see Steps to Reproduce.

(0006012) ygrek (reporter) 2011-06-16 08:34	It doesn't crash, but exits on SIGPIPE because `true` exits before output channel is flushed. Try `yes > /dev/null' instead and see. Bytecode compiled works because channel happens to be flushed before `true` is launched (race condition). `unix_dup` is not found in last example because you shouldn't use ocamlrun to run executables with custom runtime.

(0006013) cvp (reporter) 2011-06-16 17:24	In that case, shouldn't the interactive toplevel handle a SIGPIPE a little more gracefully? Because all the user sees is a sudden termination without an explanation.

(0006080) doligez (manager) 2011-08-03 17:59	You have your explanation right here: # flush p_out ;; (* crashes *) $ echo $? 141 The termination code is 128 + 13. The 128 is a flag telling you that the process was killed by a signal, and the 13 is the signal number (SIGPIPE). Maybe the shell should report exit codes more explicitely ? Should we try to catch all signals? And what do we do when we get one?

Issue History
Date Modified	Username	Field	Change
2011-06-15 21:57	cvp	New Issue
2011-06-15 21:58	cvp	Note Added: 0006011
2011-06-16 08:34	ygrek	Note Added: 0006012
2011-06-16 17:24	cvp	Note Added: 0006013
2011-08-03 17:59	doligez	Note Added: 0006080
2011-08-03 18:00	doligez	Status	new => resolved
2011-08-03 18:00	doligez	Resolution	open => no change required

Copyright © 2000 - 2011 MantisBT Group