[lxc-devel] 回复 :Re: 回复 :Re: How to change to lxc internal PID to system wide PID

[yinxb at neusoft.com]

Got it .This is just the thing.
Thanks indeed.

----- 原邮件 -----
从: Greg Kurz <gkurz at fr.ibm.com>
日期: 星期二, 十二月 13日, 2011 下午4:21
主题: Re: 回复:Re: [lxc-devel] How to change to lxc internal PID to 
system wide PID

> On Tue, 2011-12-13 at 09:49 +0800, yinxb at neusoft.com wrote:
> > Hi Gregory Kurz
> > 
> >    From the google search,SCM_CREDENTIALS contains the PID of 
> the 
> > sender process,in the sender's
> > PID namespace.
> >    So if the lxc App acts as the sender, the PID is 2 which is 
> also 
> > invalid for the host. 
> > (lxc has its own PID namesapce)
> >    Correct me if wrong,thanks.
> > 
> 
> Hi Xiaobiao,
> 
> What you say was true a long time ago, but the SCM_CREDENTIALS 
feature
> is pid namespace aware since 2.6.35: a struct cred in the kernel 
> holds a
> ref to a struct pid instead of a pid_t. The appropriate numerical 
> pid is
> returned to the caller of recvmsg() according to the following path:
> 
> unix_stream_recvmsg()->scm_set_cred()->cred_to_ucred()
> 
> Unless you run an older kernel, you can safely rely on unix 
> sockets to
> perform pid translation from the container to the host.
> 
> Cheers.
> 
> > Cheers
> > Xiaobiao
> > ----- 原邮件 -----
> > 从: Greg Kurz <gkurz at fr.ibm.com>
> > 日期: 星期一, 十二月 12日, 2011 下午6:08
> > 主题: Re: [lxc-devel] How to change to lxc internal PID to system 
> wide 
> > PID
> > 
> > > On Mon, 2011-12-12 at 11:01 +0800, yinxb at neusoft.com wrote:
> > > > Hi all
> > > > 
> > > >   These days I encouter a problem.
> > > >   When I use the lxc to running my app,the getpid() system 
> call 
> > > > returns 2.But in my platform,
> > > >   I need the system wide PID instead for some purpose,such 
> as 
> > > > integrade with native app(not running in lxc).
> > > >   (I want to integrade the lxc app in my platform to do 
> > > isolation,and 
> > > > use the dbus for IPC)
> > > >   So how to solve this conflict?Can anyone give me a hint? 
> > > > 
> > > >   Thanks for your time.
> > > > 
> > > > Cheers
> > > > Xiaobiao
> > > 
> > > Hi Xiaobiao,
> > > 
> > > This is a recurring need from the lxc community... For the 
> moment, 
> > the
> > > only kernel service that provides PID conversions is 
> 'ancillary 
> > > messageson AF_UNIX sockets'. Look for SCM_CREDENTIALS in 
> unix(7). 
> > > All you need
> > > is connected unix socket between your container and the host 
> system.> > 
> > > Cheers.
> > > 
> > > -- 
> > > Gregory Kurz                                     gkurz at fr.ibm.com
> > > Software Engineer @ IBM/Meiosys                  
> http://www.ibm.com> > Tel +33 (0)534 638 479                       
>    Fax +33 (0)561 
> > > 400 420
> > > 
> > > "Anarchy is about taking complete responsibility for yourself."
> > >        Alan Moore.
> > > 
> > > 
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> -- 
> Gregory Kurz                                     gkurz at fr.ibm.com
> Software Engineer @ IBM/Meiosys                  http://www.ibm.com
> Tel +33 (0)534 638 479                           Fax +33 (0)561 
> 400 420
> 
> "Anarchy is about taking complete responsibility for yourself."
>        Alan Moore.
> 
> 
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