[lxc-devel] [PATCH] Ignore trailing /init.scope in init cgroups

[Stéphane Graber]

On Thu, Oct 15, 2015 at 06:56:17PM +0000, Serge Hallyn wrote:
> The lxc monitor does not store the container's cgroups, rather it
> recalculates them whenever needed.
> 
> Systemd moves itself into a /init.scope cgroup for the systemd
> controller.
> 
> It might be worth changing that (by storing all cgroup info in the
> lxc_handler), but for now go the hacky route and chop off any
> trailing /init.scope.
> 
> I definately thinkg we want to switch to storing as that will be
> more bullet-proof, but for now we need a quick backportable fix
> for systemd 226 guests.
> 
> Signed-off-by: Serge Hallyn <serge.hallyn at ubuntu.com>

Acked-by: Stéphane Graber <stgraber at ubuntu.com>

> ---
>  src/lxc/cgfs.c      |  1 +
>  src/lxc/cgmanager.c |  1 +
>  src/lxc/cgroup.c    | 14 ++++++++++++++
>  src/lxc/cgroup.h    |  2 ++
>  4 files changed, 18 insertions(+)
> 
> diff --git a/src/lxc/cgfs.c b/src/lxc/cgfs.c
> index df2e6b2..d65f2d7 100644
> --- a/src/lxc/cgfs.c
> +++ b/src/lxc/cgfs.c
> @@ -1220,6 +1220,7 @@ static char *lxc_cgroup_get_hierarchy_path_data(const char *subsystem, struct cg
>  	info = find_info_for_subsystem(info, subsystem);
>  	if (!info)
>  		return NULL;
> +	prune_init_scope(info->cgroup_path);
>  	return info->cgroup_path;
>  }
>  
> diff --git a/src/lxc/cgmanager.c b/src/lxc/cgmanager.c
> index a677c22..f868903 100644
> --- a/src/lxc/cgmanager.c
> +++ b/src/lxc/cgmanager.c
> @@ -776,6 +776,7 @@ static char *try_get_abs_cgroup(const char *name, const char *lxcpath,
>  			nerr = nih_error_get();
>  			nih_free(nerr);
>  		}
> +		prune_init_scope(cgroup);
>  		return cgroup;
>  	}
>  
> diff --git a/src/lxc/cgroup.c b/src/lxc/cgroup.c
> index 2362ad8..b1c764f 100644
> --- a/src/lxc/cgroup.c
> +++ b/src/lxc/cgroup.c
> @@ -194,3 +194,17 @@ cgroup_driver_t cgroup_driver(void)
>  {
>  	return ops->driver;
>  }
> +
> +#define INIT_SCOPE "/init.scope"
> +void prune_init_scope(char *cg)
> +{
> +	char *point = cg + strlen(cg) - strlen(INIT_SCOPE);
> +	if (point < cg)
> +		return;
> +	if (strcmp(point, INIT_SCOPE) == 0) {
> +		if (point == cg)
> +			*(point+1) = '\0';
> +		else
> +			*point = '\0';
> +	}
> +}
> diff --git a/src/lxc/cgroup.h b/src/lxc/cgroup.h
> index 6706939..7704c04 100644
> --- a/src/lxc/cgroup.h
> +++ b/src/lxc/cgroup.h
> @@ -80,4 +80,6 @@ extern bool cgroup_unfreeze(struct lxc_handler *handler);
>  extern void cgroup_disconnect(void);
>  extern cgroup_driver_t cgroup_driver(void);
>  
> +extern void prune_init_scope(char *cg);
> +
>  #endif
> -- 
> 2.5.0
> 
> _______________________________________________
> lxc-devel mailing list
> lxc-devel at lists.linuxcontainers.org
> http://lists.linuxcontainers.org/listinfo/lxc-devel

-- 
Stéphane Graber
Ubuntu developer
http://www.ubuntu.com
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