From: ebiederm@xmission.com (Eric W. Biederman)
To: KOSAKI Motohiro <kosaki.motohiro@gmail.com>
Cc: Cyrill Gorcunov <gorcunov@gmail.com>,
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
linux-kernel@vger.kernel.org,
Andrew Morton <akpm@linux-foundation.org>,
Pavel Emelyanov <xemul@parallels.com>,
Serge Hallyn <serge.hallyn@canonical.com>,
Kees Cook <keescook@chromium.org>, Tejun Heo <tj@kernel.org>,
Andrew Vagin <avagin@openvz.org>,
Alexey Dobriyan <adobriyan@gmail.com>
Subject: Re: [patch 1/4] fs, proc: Introduce /proc/<pid>/task/<tid>/children entry v8
Date: Tue, 24 Jan 2012 18:11:21 -0800 [thread overview]
Message-ID: <m1r4yoedkm.fsf@fess.ebiederm.org> (raw)
In-Reply-To: <4F1F576A.9090102@gmail.com> (KOSAKI Motohiro's message of "Tue, 24 Jan 2012 20:14:18 -0500")
KOSAKI Motohiro <kosaki.motohiro@gmail.com> writes:
> (1/24/12 4:11 AM), Cyrill Gorcunov wrote:
>> On Tue, Jan 24, 2012 at 12:52:03AM -0800, Eric W. Biederman wrote:
>>> Cyrill Gorcunov<gorcunov@gmail.com> writes:
>>>
>>>> On Tue, Jan 24, 2012 at 04:07:09PM +0900, KAMEZAWA Hiroyuki wrote:
>>>>>>
>>>>>> Hmm. But userspace app will get eof, so frankly I don't see
>>>>>> a problem here. Or maybe I miss something?
>>>>>>
>>>>>
>>>>> Userspace need to take care of whether there may be"\n" or not even
>>>>> if read() returns EOF.
>>>>> As an interface, it's BUG to say "\n" will be there if you're lucky!"
>>>>> (*) I know script language can handle this but we shouldn't assume that.
>>>>>
>>>>> How about just remove "\n" at EOF ? I think it's unnecessary.
>>>>>
>>>>
>>>> Sure thing, it's not a problem to remove it completely.
>>>
>>> Foolish question. Is there any reason why this is a file instead
>>> of being the obvious directory full of symlinks?
>>>
>>
>> How would these symlinks look like? "../../pid"? There were a conversation
>> about such things (https://lkml.org/lkml/2011/12/2/142) but I suppose we
>> were agree on children with pids as consensus.
>
> I couldn't find any agreement in this link. Suppose wrong url?
Now that you have reminded me of this thread. I can say that the
link would need to look like ../../pid. Our children will always
be thread group leaders, so we can safely point to the /proc/<pid>
directories. So readlink would return ../../<pid> or however many
dots are needed. Follow link could just warp us to that directory
as it does for the other magic proc symlinks.
My feeling is that a children subdirectory would be a lot more useful
than a simple file that lists the children.
Eric
next prev parent reply other threads:[~2012-01-25 2:08 UTC|newest]
Thread overview: 60+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-01-23 14:20 [patch 0/4] A few patches in a sake of c/r functionality Cyrill Gorcunov
2012-01-23 14:20 ` [patch 1/4] fs, proc: Introduce /proc/<pid>/task/<tid>/children entry v8 Cyrill Gorcunov
2012-01-23 18:54 ` Kees Cook
2012-01-23 19:33 ` Cyrill Gorcunov
2012-01-23 20:29 ` Kees Cook
2012-01-23 20:39 ` Cyrill Gorcunov
2012-01-24 2:07 ` KAMEZAWA Hiroyuki
2012-01-24 6:53 ` Cyrill Gorcunov
2012-01-24 7:07 ` KAMEZAWA Hiroyuki
2012-01-24 7:21 ` Cyrill Gorcunov
2012-01-24 8:52 ` Eric W. Biederman
2012-01-24 9:11 ` Cyrill Gorcunov
2012-01-25 1:14 ` KOSAKI Motohiro
2012-01-25 2:11 ` Eric W. Biederman [this message]
2012-01-25 6:55 ` Cyrill Gorcunov
2012-01-25 15:29 ` Cyrill Gorcunov
2012-01-24 8:51 ` Cyrill Gorcunov
2012-01-24 23:53 ` Andrew Morton
2012-01-25 6:52 ` Cyrill Gorcunov
2012-01-23 14:20 ` [patch 2/4] [RFC] syscalls, x86: Add __NR_kcmp syscall v4 Cyrill Gorcunov
2012-01-23 18:48 ` H. Peter Anvin
2012-01-23 20:03 ` Cyrill Gorcunov
2012-01-24 2:16 ` KAMEZAWA Hiroyuki
2012-01-24 6:47 ` Cyrill Gorcunov
2012-01-24 7:04 ` H. Peter Anvin
2012-01-24 7:17 ` Cyrill Gorcunov
2012-01-24 7:20 ` KAMEZAWA Hiroyuki
2012-01-24 7:38 ` Cyrill Gorcunov
2012-01-24 7:40 ` KAMEZAWA Hiroyuki
2012-01-24 8:48 ` Cyrill Gorcunov
2012-01-24 20:20 ` KOSAKI Motohiro
2012-01-24 20:26 ` Cyrill Gorcunov
2012-01-24 20:44 ` Eric W. Biederman
2012-01-24 20:50 ` Cyrill Gorcunov
2012-01-24 21:20 ` Eric W. Biederman
2012-01-24 21:34 ` Cyrill Gorcunov
2012-01-24 21:22 ` Andrew Morton
2012-01-24 21:45 ` Andrew Morton
2012-01-24 21:46 ` H. Peter Anvin
2012-01-24 22:00 ` Andrew Morton
2012-01-24 22:52 ` H. Peter Anvin
2012-01-24 23:42 ` Andrew Morton
2012-01-24 21:46 ` Cyrill Gorcunov
2012-01-24 21:59 ` Andrew Morton
2012-01-24 22:54 ` Eric W. Biederman
2012-01-24 22:54 ` Andrew Morton
2012-01-24 21:25 ` Andrew Morton
2012-01-24 21:31 ` Cyrill Gorcunov
2012-01-24 8:49 ` Eric W. Biederman
2012-01-24 8:49 ` Cyrill Gorcunov
2012-01-23 14:20 ` [patch 3/4] c/r: procfs: add arg_start/end, env_start/end and exit_code members to /proc/$pid/stat Cyrill Gorcunov
2012-01-23 20:42 ` Kees Cook
2012-01-23 20:53 ` Cyrill Gorcunov
2012-01-24 23:59 ` Andrew Morton
2012-01-25 6:54 ` Cyrill Gorcunov
2012-01-25 7:12 ` Andrew Morton
2012-01-25 7:18 ` Cyrill Gorcunov
2012-01-23 14:20 ` [patch 4/4] c/r: prctl: Extend PR_SET_MM to set up more mm_struct entries Cyrill Gorcunov
2012-01-23 15:55 ` Cyrill Gorcunov
2012-01-23 20:02 ` Cyrill Gorcunov
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