[lxc-devel] [PATCH 2/3] execute: bind init.lxc.static into container

[Dwight Engen]

On Mon, 12 May 2014 18:04:00 +0000
Serge Hallyn <serge.hallyn at ubuntu.com> wrote:

> Signed-off-by: Serge Hallyn <serge.hallyn at ubuntu.com>
> ---
>  src/lxc/conf.c | 58
> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file
> changed, 58 insertions(+)
> 
> diff --git a/src/lxc/conf.c b/src/lxc/conf.c
> index 7427a94..0580f46 100644
> --- a/src/lxc/conf.c
> +++ b/src/lxc/conf.c
> @@ -3811,6 +3811,61 @@ static void remount_all_slave(void)
>  		free(line);
>  }
>  
> +void lxc_execute_bind_init(struct lxc_conf *conf)
> +{
> +	int ret;
> +	char path[PATH_MAX], destpath[PATH_MAX];
> +
> +	ret = snprintf(path, PATH_MAX, SBINDIR "/init.lxc.static");
> +	if (ret < 0 || ret >= PATH_MAX) {
> +		WARN("Path name too long searching for
> lxc.init.static");
> +		return;
> +	}
> +
> +	if (!file_exists(path)) {
> +		INFO("%s does not exist on host", path);
> +		return;
> +	}
> +
> +	ret = snprintf(destpath, PATH_MAX, "%s%s",
> conf->rootfs.mount, path);
> +	if (ret < 0 || ret >= PATH_MAX) {
> +		WARN("Path name too long for container's
> lxc.init.static");
> +		return;
> +	}
> +
> +	if (!file_exists(destpath)) {
> +		FILE *pathfile;
> +		char *pathdirname = strdup(path);
> +
> +		if (!pathdirname) {
> +			SYSERROR("Out of memory binding
> lxc.init.static into container");
> +			return;
> +		}
> +		pathdirname = dirname(pathdirname);
> +		ret = mkdir_p(pathdirname, 0755);
> +		free(pathdirname);
> +		if (ret < 0) {
> +			/*
> +			 * this can fail just due to read-only bind
> mounts.  Trust
> +			 * that the user knows what they want, log
> and proceed
> +			 */
> +			WARN("Failed to create %s in container",
> SBINDIR);
> +			return;
> +		}
> +		pathfile = fopen(destpath, "wb");

Hi Serge, are you sure you want to truncate destpath in case it exists?
Maybe you want "ab"?

> +		if (!pathfile) {
> +			SYSERROR("Failed to create mount target
> '%s'", destpath);
> +			return;
> +		}
> +		fclose(pathfile);
> +	}
> +
> +	ret = mount(path, destpath, "none", MS_BIND, NULL);
> +	if (ret < 0)
> +		SYSERROR("Failed to bind lxc.init.static into
> container");
> +	INFO("lxc.init.static bound into container at %s", path);
> +}
> +
>  int lxc_setup(struct lxc_handler *handler)
>  {
>  	const char *name = handler->name;
> @@ -3878,6 +3933,9 @@ int lxc_setup(struct lxc_handler *handler)
>  		return -1;
>  	}
>  
> +	if (lxc_conf->is_execute)
> +		lxc_execute_bind_init(lxc_conf);
> +
>  	/* now mount only cgroup, if wanted;
>  	 * before, /sys could not have been mounted
>  	 * (is either mounted automatically or via fstab entries)