code review 5700045: os: make Wait return on SIGSTOP on linux (issue 5700045)

[byt...@gmail.com]

Reviewers: golang-dev_googlegroups.com,

Message:
Hello golan...@googlegroups.com (cc: golan...@googlegroups.com),

I'd like you to review this change to
https://go.googlecode.com/hg/

Description:
os: make Wait return on SIGSTOP on linux

Fixes issue 3111.

Please review this at http://codereview.appspot.com/5700045/

Affected files:
M src/pkg/os/exec_unix.go

Index: src/pkg/os/exec_unix.go
===================================================================
--- a/src/pkg/os/exec_unix.go
+++ b/src/pkg/os/exec_unix.go
@@ -21,7 +21,7 @@
}
var status syscall.WaitStatus
var rusage syscall.Rusage
- pid1, e := syscall.Wait4(p.Pid, &status, 0, &rusage)
+ pid1, e := syscall.Wait4(p.Pid, &status, syscall.WSTOPPED, &rusage)
if e != nil {
return nil, NewSyscallError("wait", e)
}

[minux]

issue description: s/linux/unix/, this is not linux specific change.

Why not add WCONTINUED and WUNTRACED as well?

[Scott Lawrence]

Agreed on both; changed.

On Thu, 23 Feb 2012, minux wrote:

> issue description: s/linux/unix/, this is not linux specific change.
>
> Why not add WCONTINUED and WUNTRACED as well?
>

--
Scott Lawrence

Linux jagadai 3.2.5-1-ARCH #1 SMP PREEMPT Tue Feb 7 08:34:36 CET 2012 x86_64 Intel(R) Core(TM)2 Duo CPU P8700 @ 2.53GHz GenuineIntel GNU/Linux

[Ian Lance Taylor]

FYI

I understand that it is good to be able to see whether a process has
stopped, but I think there has to be a way to simply wait for a process
to exit. It shouldn't be necessary to call Wait() in a loop.

Ian

[Scott Lawrence]

Perhaps add WaitSignal with the new behavior, and leave Wait, then?

--

[Russ Cox]

No thanks.

Package os is for portable behavior, and this is not portable.
Process.Wait is for waiting for a process to be gone, not
for it to SIGSTOP. If you want the latter, use package
syscall directly.

Russ

[Scott Lawrence]

Is either behavior portable? I ask because right now, the windows
implementation seems more analagous to using WSTOPPED et al.

--

[Russ Cox]

Process.Wait is defined to wait for the process to
exit/be killed/never going to run again/whatever.
If Windows isn't doing that, that's the bug we should fix.