[CRIU] [PATCH 03/14] util: clone service descriptors, if fd tables are shared for tasks (v3)

[Andrew Vagin]

On Fri, Jan 11, 2013 at 02:34:01PM +0400, Pavel Emelyanov wrote:
> 
> > +int clone_service_fd(int id)
> > +{
> > +	int ret = -1, i;
> > +
> > +	if (service_fd_id == id)
> > +		return 0;
> 
> What does this check mean? Does it "shoot" ever? When?
The current process is already in a proper namespace.

If two process doesn't share fd tables, they will call
clone_service_fd(0).

> 
> > +
> > +	for (i = SERVICE_FD_MIN + 1; i < SERVICE_FD_MAX; i++) {
> > +		int old = __get_service_fd(i, service_fd_id);
> > +		int new = __get_service_fd(i, id);
> > +
> > +		ret = dup2(old, new);
> > +		if (ret == -1) {
> > +			if (errno == EBADF)
> > +				continue;
> > +			pr_perror("Unalbe to clone %d->%d\n", old, new);
> > +		}
> > +	}
> > +
> > +	service_fd_id = id;
> > +	ret = 0;
> > +
> > +	return ret;
> >  }