code review 5700045: os: make Wait return on SIGSTOP on unix

os: make Wait return on SIGSTOP on unix

Fixes issue 3111.

[bytbox, 2012-02-23 09:41:22]

Hello golang-dev@googlegroups.com (cc: golang-dev@googlegroups.com),

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

[minux1, 2012-02-23 09:52:47]

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

Why not add WCONTINUED and WUNTRACED as well?

[bytbox, 2012-02-23 10:12:44]

Hello golang-dev@googlegroups.com, minux.ma@gmail.com (cc:
golang-dev@googlegroups.com),

Please take another look.

[bytbox, 2012-02-23 10:13:04]

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

[iant2, 2012-02-23 13:10:26]

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


bytbox@gmail.com writes:

> Reviewers: golang-dev_googlegroups.com,
>
> Message:
> Hello golang-dev@googlegroups.com (cc: golang-dev@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)
>  	}

[bytbox, 2012-02-23 16:07:40]

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

On Thu, 23 Feb 2012, Ian Lance Taylor wrote:

> 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
>
>
> bytbox@gmail.com writes:
>
>> Reviewers: golang-dev_googlegroups.com,
>>
>> Message:
>> Hello golang-dev@googlegroups.com (cc: golang-dev@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)
>>  	}
>

-- 
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

[rsc, 2012-02-23 16:44:30]

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

[bytbox, 2012-02-23 16:51:31]

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

On Thu, 23 Feb 2012, Russ Cox wrote:

> 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

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

[rsc, 2012-02-23 16:57:15]

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.

[rsc, 2012-02-23 20:30:07]

Removing reviewers.

[bytbox, 2012-02-23 20:34:47]

*** Abandoned ***