[lxc-devel] [PATCH] c/r: factor out network dump/restore code

[Serge Hallyn]

Quoting Tycho Andersen (tycho.andersen at canonical.com):
> Break the monolithic ->checkpoint and ->restore functions into smaller ones.
> This is in preparation for the checkpoint/restore tty work, which has a similar
> need to dump information outside of criu.
> 
> Signed-off-by: Tycho Andersen <tycho.andersen at canonical.com>

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

> ---
>  src/lxc/lxccontainer.c | 128 ++++++++++++++++++++++++++-----------------------
>  1 file changed, 69 insertions(+), 59 deletions(-)
> 
> diff --git a/src/lxc/lxccontainer.c b/src/lxc/lxccontainer.c
> index 4c3d4d5..703042a 100644
> --- a/src/lxc/lxccontainer.c
> +++ b/src/lxc/lxccontainer.c
> @@ -3698,30 +3698,21 @@ static bool criu_ok(struct lxc_container *c)
>  	return true;
>  }
>  
> -static bool lxcapi_checkpoint(struct lxc_container *c, char *directory, bool stop, bool verbose)
> +static bool dump_net_info(struct lxc_container *c, char *directory)
>  {
> -	int netnr, status;
> +	int netnr;
>  	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;
> +		bool has_error = true;
>  		int pret;
>  
>  		pret = snprintf(veth_path, PATH_MAX, "lxc.network.%d.veth.pair", netnr);
> -		if (pret < 0 || pret >= PATH_MAX) {
> -			error = true;
> +		if (pret < 0 || pret >= PATH_MAX)
>  			goto out;
> -		}
>  
>  		veth = lxcapi_get_running_config_item(c, veth_path);
>  		if (!veth) {
> @@ -3733,49 +3724,59 @@ static bool lxcapi_checkpoint(struct lxc_container *c, char *directory, bool sto
>  		}
>  
>  		pret = snprintf(veth_path, PATH_MAX, "lxc.network.%d.link", netnr);
> -		if (pret < 0 || pret >= PATH_MAX) {
> -			error = true;
> +		if (pret < 0 || pret >= PATH_MAX)
>  			goto out;
> -		}
>  
>  		bridge = lxcapi_get_running_config_item(c, veth_path);
> -		if (!bridge) {
> -			error = true;
> +		if (!bridge)
>  			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;
> +		if (pret < 0 || pret >= PATH_MAX || print_to_file(veth_path, veth) < 0)
>  			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;
> +		if (pret < 0 || pret >= PATH_MAX || print_to_file(veth_path, bridge) < 0)
>  			goto out;
> -		}
>  
>  		if (n->name) {
> -			if (strlen(n->name) >= 128) {
> -				error = true;
> +			if (strlen(n->name) >= 128)
>  				goto out;
> -			}
>  			strncpy(eth, n->name, 128);
>  		} 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;
> +			goto out;
>  
> +		has_error = false;
>  out:
> -		free(veth);
> -		free(bridge);
> -		if (error)
> +		if (veth)
> +			free(veth);
> +		if (bridge);
> +			free(bridge);
> +		if (has_error)
>  			return false;
>  	}
>  
> +	return true;
> +}
> +
> +static bool lxcapi_checkpoint(struct lxc_container *c, char *directory, bool stop, bool verbose)
> +{
> +	pid_t pid;
> +	int status;
> +
> +	if (!criu_ok(c))
> +		return false;
> +
> +	if (mkdir(directory, 0700) < 0 && errno != EEXIST)
> +		return false;
> +
> +	if (!dump_net_info(c, directory))
> +		return false;
> +
>  	pid = fork();
>  	if (pid < 0)
>  		return false;
> @@ -3807,10 +3808,42 @@ out:
>  	}
>  }
>  
> +static bool restore_net_info(struct lxc_container *c, char *directory)
> +{
> +	struct lxc_list *it;
> +	bool has_error = true;
> +	int netnr = 0;
> +
> +	if (container_mem_lock(c))
> +		return false;
> +
> +	lxc_list_for_each(it, &c->lxc_conf->network) {
> +		char eth[128], veth[128];
> +		struct lxc_netdev *netdev = it->elem;
> +
> +		if (read_criu_file(directory, "veth", netnr, veth))
> +			goto out_unlock;
> +
> +		if (read_criu_file(directory, "eth", netnr, eth))
> +			goto out_unlock;
> +
> +		netdev->priv.veth_attr.pair = strdup(veth);
> +		if (!netdev->priv.veth_attr.pair)
> +			goto out_unlock;
> +
> +		netnr++;
> +	}
> +
> +	has_error = false;
> +
> +out_unlock:
> +	container_mem_unlock(c);
> +	return !has_error;
> +}
> +
>  static bool lxcapi_restore(struct lxc_container *c, char *directory, bool verbose)
>  {
>  	pid_t pid;
> -	struct lxc_list *it;
>  	struct lxc_rootfs *rootfs;
>  	char pidfile[L_tmpnam];
>  	struct lxc_handler *handler;
> @@ -3896,7 +3929,7 @@ static bool lxcapi_restore(struct lxc_container *c, char *directory, bool verbos
>  				goto out_fini_handler;
>  			}
>  			else {
> -				int netnr = 0, ret;
> +				int ret;
>  				FILE *f = fopen(pidfile, "r");
>  				if (!f) {
>  					perror("reading pidfile");
> @@ -3911,34 +3944,11 @@ static bool lxcapi_restore(struct lxc_container *c, char *directory, bool verbos
>  					goto out_fini_handler;
>  				}
>  
> -				if (container_mem_lock(c))
> +				if (!restore_net_info(c, directory)) {
> +					ERROR("failed restoring network info");
>  					goto out_fini_handler;
> -
> -				lxc_list_for_each(it, &c->lxc_conf->network) {
> -					char eth[128], veth[128];
> -					struct lxc_netdev *netdev = it->elem;
> -
> -					if (read_criu_file(directory, "veth", netnr, veth)) {
> -						container_mem_unlock(c);
> -						goto out_fini_handler;
> -					}
> -
> -					if (read_criu_file(directory, "eth", netnr, eth)) {
> -						container_mem_unlock(c);
> -						goto out_fini_handler;
> -					}
> -
> -					netdev->priv.veth_attr.pair = strdup(veth);
> -					if (!netdev->priv.veth_attr.pair) {
> -						container_mem_unlock(c);
> -						goto out_fini_handler;
> -					}
> -
> -					netnr++;
>  				}
>  
> -				container_mem_unlock(c);
> -
>  				if (lxc_set_state(c->name, handler, RUNNING))
>  					goto out_fini_handler;
>  			}
> -- 
> 1.9.1
> 
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