[CRIU] [PATCH 2/2] remap: add a dead pid /proc remap

[Tycho Andersen]

On Wed, Sep 10, 2014 at 07:21:55PM +0400, Pavel Emelyanov wrote:
> 
> > @@ -227,6 +228,28 @@ static int open_remap_linked(struct reg_file_info *rfi,
> >  	return 0;
> >  }
> >  
> > +static int open_remap_dead_process(struct reg_file_info *rfi,
> > +		RemapFilePathEntry *rfe)
> > +{
> > +	struct pstree_item *helper;
> > +
> > +	helper = alloc_pstree_item_with_rst();
> > +	if (!helper)
> > +		return -1;
> > +
> > +	helper->sid = root_item->sid;
> > +	helper->pgid = root_item->sid;
> > +	helper->pid.virt = rfe->remap_id;
> 
> BTW, a helper with such pid may already be in the tree. E.g.
> you have a dead task with pid 20 and living task with pgid 20.
> In this case CRIU would create a helper with pid 20 to make
> the pgid restore for the latter one work.

Good point. Another possibility is that two other tasks have the same
dead pid's files open. This code should check to see if the pid is
already in the tree as a TASK_HELPER before it adds one, I suppose.

Tycho

> > +	helper->state = TASK_HELPER;
> > +	helper->parent = root_item;
> > +	list_add_tail(&helper->sibling, &root_item->children);
> > +	task_entries->nr_helpers++;
> > +
> > +	pr_info("Added a helper for restoring /proc/%d\n", helper->pid.virt);
> > +
> > +	return 0;
> > +}
> > +
> >  static int collect_one_remap(void *obj, ProtobufCMessage *msg)
> >  {
> >  	int ret = -1;
>