[lxc-devel] [PATCH] Add support for checkpoint and restore via CRIU

[Serge Hallyn]

Quoting Tycho Andersen (tycho.andersen at canonical.com):

Thanks, Tycho.  Just one remaining request below.  Other than that,

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

> +static bool lxcapi_checkpoint(struct lxc_container *c, char *directory, bool stop, bool verbose)
> +{
> +	int netnr, status;
> +	struct lxc_list *it;
> +	bool error = false;
> +	pid_t pid;
> +
> +	if (!criu_ok(c))
> +		return false;
> +
> +	if (mkdir(directory, 0700) < 0 && errno != EEXIST)
> +		return false;
> +
> +	netnr = 0;
> +	lxc_list_for_each(it, &c->lxc_conf->network) {
> +		char *veth = NULL, *bridge = NULL, veth_path[PATH_MAX], eth[128];
> +		struct lxc_netdev *n = it->elem;
> +		int pret;
> +
> +		pret = snprintf(veth_path, PATH_MAX, "lxc.network.%d.veth.pair", netnr);
> +		if (pret < 0 || pret >= PATH_MAX) {
> +			error = true;
> +			goto out;
> +		}
> +
> +		veth = lxcapi_get_running_config_item(c, veth_path);
> +		if (!veth) {
> +			/* criu_ok() checks that all interfaces are
> +			 * LXC_NET{VETH,NONE}, and VETHs should have this
> +			 * config */
> +			assert(n->type == LXC_NET_NONE);
> +			break;
> +		}
> +
> +		pret = snprintf(veth_path, PATH_MAX, "lxc.network.%d.link", netnr);
> +		if (pret < 0 || pret >= PATH_MAX) {
> +			error = true;
> +			goto out;
> +		}
> +
> +		bridge = lxcapi_get_running_config_item(c, veth_path);
> +		if (!bridge) {
> +			error = true;
> +			goto out;
> +		}
> +
> +		pret = snprintf(veth_path, PATH_MAX, "%s/veth%d", directory, netnr);
> +		if (pret < 0 || pret >= PATH_MAX || print_to_file(veth_path, veth) < 0) {
> +			error = true;
> +			goto out;
> +		}
> +
> +		pret = snprintf(veth_path, PATH_MAX, "%s/bridge%d", directory, netnr);
> +		if (pret < 0 || pret >= PATH_MAX || print_to_file(veth_path, bridge) < 0) {
> +			error = true;
> +			goto out;
> +		}
> +
> +		if (n->name) {
> +			assert(strlen(n->name) <= 127);
> +			strncpy(eth, n->name, 128);

This again is an API function so I don't want asserts there if we can help
it.  I was thinking

	strncpy(eth, n->name, 127);

Is there a good reason to do it this way?

> +		} else
> +			sprintf(eth, "eth%d", netnr);
> +
> +		pret = snprintf(veth_path, PATH_MAX, "%s/eth%d", directory, netnr);
> +		if (pret < 0 || pret >= PATH_MAX || print_to_file(veth_path, eth) < 0)
> +			error = true;
> +
> +out:
> +		free(veth);
> +		free(bridge);
> +		if (error)
> +			return false;
> +	}