Re: [PATCH 0/2] ptrace: add ability to attach a file descriptor toanother process

From: Tejun Heo
Date: Fri Dec 16 2011 - 11:06:05 EST


Hello,

On Fri, Dec 16, 2011 at 01:46:21PM +0300, Andrew Vagin wrote:
> We need this functionality for checkpointing processes. Now some parts
> are dumped with help PTRACE_SEIZE. Parasite code is injected to process
> and it collects information. This code should save data to somewhere.
> I want to suggest a scheme, when a dumper creates file descriptor and
> attaches it to a target process, then execute parasite code, which closes
> this descriptor at the end.
>
> We can't create unix sockets or open files, because a process may
> be in another namespaces.

I really dislike this. This doesn't belong in ptrace at all. With
parasite, you have full control of the process, there gotta be some
other way to talk back. Can't you create a management process w/ open
UNIX socket when spawning a namespace? If that doesn't work, wouldn't
letting it dump to filesystem and retrieving it afterwards work?

Thanks.

--
tejun
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