[CRIU] Re: [PATCH v2] parasite-syscall: some cleanup

[Cyrill Gorcunov]

On Tue, Feb 21, 2012 at 07:19:06PM +0300, Kinsbursky Stanislav wrote:
> v2: command is set prior to parasite_execute() call now
> 
> Removed redundant on-stack variables typeof parasite_status_t and memcpy
> between them and parasite_ctl->addr_args object. Ando a lot of cleanup done
> around.
> 
> Signed-off-by: Stanislav Kinsbursky <skinsbursky at openvz.org>
> ---

I thought it'll be a good idea, but after looking into final code
I fear it's not.

Lets clean it up step-by-step (I'm enumerating what we have now
and some ideas so we would choose ones which are suitable for us)

1) Every parasite argument passed must have a header with

	parasite_status_t       status;

   on top, where the parasite will write the result of operations
   on return (if there some code where we do not write the result
   I think we should add it).

2) If parasite finished without error we should use some macro such
   as say

#define SET_PARASITE_STATUS_SUCCESS(st)			\
	do {						\
		(st)->ret	= 0,			\
		(st)->sys_ret	= 0,			\
		(st)->line	= __LINE__;		\
	} while (0)

3) Parasite alway should pick up arguments. Explicitly. If there
   a command which requires no arguments -- we must zap arguments space with
   some predefined poisoned values, so we will be able to catch cases
   when parasite is called with some command but for some reason caller
   forgot to pass new arguments.

   Agreed?

Something like that I think.

	Cyrill