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Re: [libvirt] [PATCH] LXC: make sure fuse thread start to run before we do clone

From: Eric Blake <eblake at redhat dot com>
To: Rich Felker <dalias at aerifal dot cx>, "Daniel P. Berrange" <berrange at redhat dot com>
Cc: libvir-list at redhat dot com, libc-alpha at sourceware dot org
Date: Wed, 13 Nov 2013 11:33:46 -0700
Subject: Re: [libvirt] [PATCH] LXC: make sure fuse thread start to run before we do clone
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On 11/13/2013 11:16 AM, Rich Felker wrote:

>> We are not using clone() in a manner that is strictly equivalent
>> to fork(). Libvirt is using clone() to create Linux containers
>> with new namespaces. eg we do 
>>
>>   clone(CLONE_NEWPID|CLONE_NEWNS|CLONE_NEWUTS|CLONE_NEWIPC|CLONE_NEWUSER|CLONE_NEWNET|SIGCHLD)
> 
> Understood. I still call this a fork-like manner since it's not
> sharing VM or using CLONE_THREAD and using the default signal of
> SIGCHLD. BTW is there a reason to prefer this usage over regular fork
> followed by unshare()?

Yes.  Per 'man 2 unshare', CLONE_NEWPID is not supported with unshare(),
yet we require our child to have pid 1 in its new pid namespace.

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org

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Follow-Ups:
- Re: [libvirt] [PATCH] LXC: make sure fuse thread start to run before we do clone
  - From: Daniel P. Berrange

References:
- Re: [libvirt] [PATCH] LXC: make sure fuse thread start to run before we do clone
  - From: Daniel P. Berrange
- Re: [libvirt] [PATCH] LXC: make sure fuse thread start to run before we do clone
  - From: Rich Felker
- Re: [libvirt] [PATCH] LXC: make sure fuse thread start to run before we do clone
  - From: Daniel P. Berrange
- Re: [libvirt] [PATCH] LXC: make sure fuse thread start to run before we do clone
  - From: Rich Felker

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