libcriu: add join_ns API

In runc we use the join-ns RPC API to enable checkpoint/restore of
containers with shared namespaces. Shared namespaces are often used
when containers run inside Kubernetes Pod.

In crun we use libcriu to interface with CRIU, however it currently
doesn't provide an API for join-ns. This patch adds the necessary
libcriu API to enable checkpoint/restore of containers with shared
namespaces with crun.

Signed-off-by: Radostin Stoyanov <radostin@redhat.com>

2 files changed, 93 insertions, 0 deletions

diff --git a/lib/c/criu.c b/lib/c/criu.c
index 75f168799..ddc6e0731 100644
--- a/lib/c/criu.c
+++ b/lib/c/criu.c
@@ -214,6 +214,18 @@ void criu_local_free_opts(criu_opts *opts)
 	}
 	opts->rpc->n_external = 0;
 
+	if (opts->rpc->join_ns) {
+		for (i = 0; i < opts->rpc->n_join_ns; i++) {
+			free(opts->rpc->join_ns[i]->ns);
+			free(opts->rpc->join_ns[i]->ns_file);
+			if (opts->rpc->join_ns[i]->extra_opt) {
+				free(opts->rpc->join_ns[i]->extra_opt);
+			}
+			free(opts->rpc->join_ns[i]);
+		}
+	}
+	opts->rpc->n_join_ns = 0;
+
 	if (opts->rpc->ps) {
 		free(opts->rpc->ps->address);
 		free(opts->rpc->ps);
@@ -1804,3 +1816,82 @@ int criu_set_network_lock(enum criu_network_lock_method method)
 {
 	return criu_local_set_network_lock(global_opts, method);
 }
+
+int criu_local_join_ns_add(criu_opts *opts, const char *ns, const char *ns_file, const char *extra_opt)
+{
+	int n_join_ns;
+	char *_ns = NULL, *_ns_file = NULL, *_extra_opt = NULL;
+	JoinNamespace **join_ns_arr, *join_ns = NULL;
+
+	if (!ns) {
+		fprintf(stderr, "ns parameter for join_ns is not specified");
+		goto err;
+	}
+
+	_ns = strdup(ns);
+	if (!_ns) {
+		perror("Can't allocate memory for ns");
+		goto err;
+	}
+
+	if (!ns_file) {
+		fprintf(stderr, "ns parameter for join_ns is not specified");
+		goto err;
+	}
+
+	_ns_file = strdup(ns_file);
+	if (!_ns_file) {
+		perror("Can't allocate memory for ns_file");
+		goto err;
+	}
+
+	if (extra_opt) {
+		_extra_opt = strdup(extra_opt);
+		if (!_extra_opt) {
+			perror("Can't allocate memory for extra_opt");
+			goto err;
+		}
+	}
+
+	join_ns = malloc(sizeof(JoinNamespace));
+	if (!join_ns) {
+		perror("Can't allocate memory for join_ns");
+		goto err;
+	}
+
+	n_join_ns = opts->rpc->n_join_ns + 1;
+	join_ns_arr = realloc(opts->rpc->join_ns, n_join_ns * sizeof(join_ns));
+	if (!join_ns_arr) {
+		perror("Can't allocate memory for join_ns_arr");
+		goto err;
+	}
+
+	join_namespace__init(join_ns);
+	join_ns->ns = _ns;
+	join_ns->ns_file = _ns_file;
+	if (_extra_opt) {
+		join_ns->extra_opt = _extra_opt;
+	}
+
+	join_ns_arr[n_join_ns - 1] = join_ns;
+	opts->rpc->join_ns = join_ns_arr;
+	opts->rpc->n_join_ns = n_join_ns;
+
+	return 0;
+
+err:
+	if (_ns)
+		free(_ns);
+	if (_ns_file)
+		free(_ns_file);
+	if (_extra_opt)
+		free(_extra_opt);
+	if (join_ns)
+		free(join_ns);
+	return -1;
+}
+
+int criu_join_ns_add(const char *ns, const char *ns_file, const char *extra_opt)
+{
+	return criu_local_join_ns_add(global_opts, ns, ns_file, extra_opt);
+}
diff --git a/lib/c/criu.h b/lib/c/criu.h
index 258e33a19..c32f66418 100644
--- a/lib/c/criu.h
+++ b/lib/c/criu.h
@@ -103,6 +103,7 @@ int criu_set_page_server_address_port(const char *address, int port);
 int criu_set_pre_dump_mode(enum criu_pre_dump_mode mode);
 void criu_set_pidfd_store_sk(int sk);
 int criu_set_network_lock(enum criu_network_lock_method method);
+int criu_join_ns_add(const char *ns, const char *ns_file, const char *extra_opt);
 
 /*
  * The criu_notify_arg_t na argument is an opaque
@@ -263,6 +264,7 @@ int criu_local_set_page_server_address_port(criu_opts *opts, const char *address
 int criu_local_set_pre_dump_mode(criu_opts *opts, enum criu_pre_dump_mode mode);
 void criu_local_set_pidfd_store_sk(criu_opts *opts, int sk);
 int criu_local_set_network_lock(criu_opts *opts, enum criu_network_lock_method method);
+int criu_local_join_ns_add(criu_opts *opts, const char *ns, const char *ns_file, const char *extra_opt);
 
 void criu_local_set_notify_cb(criu_opts *opts, int (*cb)(char *action, criu_notify_arg_t na));