[lxc-devel] [PATCH 1/3] lxc-start: fix the container leak when daemonize

[Serge Hallyn]

Quoting Qiang Huang (h.huangqiang at huawei.com):
> On 2014/1/24 1:17, Serge Hallyn wrote:
> > Quoting Qiang Huang (h.huangqiang at huawei.com):
> >> I already reasoned in the added comment, we need this because if not,
> >> lxc_container won't be freed when daemon exits, and PID file won't
> >> be unlinked either.
> > 
> > I see, but
> > 
> >> What about this:
> >>
> >> From 80f3862f9c4dbc8a05e79e50c50e79e30ffebc25 Mon Sep 17 00:00:00 2001
> >> From: Qiang Huang <h.huangqiang at huawei.com>
> >> Date: Thu, 23 Jan 2014 14:25:31 +0800
> >> Subject: [PATCH] daemon: add lxc_container_put to free container when daemon exits
> >>
> >> PID file in lxc_container is unlinked when lxc_container_free,
> >> if we leak the container, the PID file also won't be removed
> >> after container down.
> >>
> >> Signed-off-by: Qiang Huang <h.huangqiang at huawei.com>
> > 
> > I was about to ack this, but then it occurred to me that
> > this seems to show that the pidfile free shouldn't be done
> > through lxc_container_free().  The pidfile always gets
> > written right before the reboot: label, and should simply be
> > explicitly removed in the place where you are adding a
> > lxc_container_put().  That way it is symmetric;  by having
> > it in lxc_container_free(), it is not.
> > 
> 
> You are right, please review this:
> 
> ---
> 
> From 4ed573856d9f0ec56b8e522efd40f986a0409aa1 Mon Sep 17 00:00:00 2001
> From: Qiang Huang <h.huangqiang at huawei.com>
> Date: Fri, 24 Jan 2014 11:41:27 +0800
> Subject: [PATCH] lxccontainer: remove PID file after lxc_start return
> 
> Make the way symmetric. This also fix the file leak in
> daemon model.
> 
> Signed-off-by: Qiang Huang <h.huangqiang at huawei.com>

Thanks, perfect!

Acked-by: Serge E. Hallyn <serge.hallyn at ubuntu.com>

> ---
>  src/lxc/lxccontainer.c | 11 ++++++-----
>  1 file changed, 6 insertions(+), 5 deletions(-)
> 
> diff --git a/src/lxc/lxccontainer.c b/src/lxc/lxccontainer.c
> index 1520cd3..9ebb27e 100644
> --- a/src/lxc/lxccontainer.c
> +++ b/src/lxc/lxccontainer.c
> @@ -233,11 +233,6 @@ static void lxc_container_free(struct lxc_container *c)
>  		free(c->config_path);
>  		c->config_path = NULL;
>  	}
> -	if (c->pidfile) {
> -		unlink(c->pidfile);
> -		free(c->pidfile);
> -		c->pidfile = NULL;
> -	}
> 
>  	free(c);
>  }
> @@ -665,6 +660,12 @@ reboot:
>  		goto reboot;
>  	}
> 
> +	if (c->pidfile) {
> +		unlink(c->pidfile);
> +		free(c->pidfile);
> +		c->pidfile = NULL;
> +	}
> +
>  	if (daemonize)
>  		exit (ret == 0 ? true : false);
>  	else
> -- 
> 1.8.3
> 
> 
>