network: remove netpipe

We use data_sock for all things we need to send around between parent and child
now. It doesn't make sense to have so many different pipes and sockets if one
will do just fine.

Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

diff --git a/src/lxc/network.c b/src/lxc/network.c
index 1e96c3a68bbea2d73983c548e964c18e42205a36..1d62ad02c64e311be39e835c61c5008078eeff3d 100644 (file)
--- a/src/lxc/network.c
+++ b/src/lxc/network.c
@@ -45,6 +45,7 @@
 #include <sys/stat.h>
 #include <sys/types.h>
 
+#include "af_unix.h"
 #include "conf.h"
 #include "config.h"
 #include "log.h"
@@ -2991,3 +2992,65 @@ int lxc_setup_network_in_child_namespaces(const struct lxc_conf *conf,
 
        return 0;
 }
+
+int lxc_network_send_veth_names_to_child(struct lxc_handler *handler)
+{
+       struct lxc_list *iterator;
+       struct lxc_list *network = &handler->conf->network;
+       int data_sock = handler->data_sock[0];
+
+       if (handler->root)
+               return 0;
+
+       lxc_list_for_each(iterator, network) {
+               int ret;
+               struct lxc_netdev *netdev = iterator->elem;
+
+               if (netdev->type != LXC_NET_VETH)
+                       continue;
+
+               ret = lxc_abstract_unix_send_credential(data_sock, netdev->name,
+                                                       IFNAMSIZ);
+               if (ret < 0) {
+                       close(handler->data_sock[0]);
+                       close(handler->data_sock[1]);
+                       return -1;
+               } else {
+                       TRACE("Sent network device name \"%s\" to child",
+                             netdev->name);
+               }
+       }
+
+       return 0;
+}
+
+int lxc_network_recv_veth_names_from_parent(struct lxc_handler *handler)
+{
+       struct lxc_list *iterator;
+       struct lxc_list *network = &handler->conf->network;
+       int data_sock = handler->data_sock[1];
+
+       if (handler->root)
+               return 0;
+
+       lxc_list_for_each(iterator, network) {
+               int ret;
+               struct lxc_netdev *netdev = iterator->elem;
+
+               if (netdev->type != LXC_NET_VETH)
+                       continue;
+
+               ret = lxc_abstract_unix_rcv_credential(data_sock, netdev->name,
+                                                      IFNAMSIZ);
+               if (ret < 0) {
+                       close(handler->data_sock[0]);
+                       close(handler->data_sock[1]);
+                       return -1;
+               } else {
+                       TRACE("Received network device name \"%s\" from parent",
+                             netdev->name);
+               }
+       }
+
+       return 0;
+}

diff --git a/src/lxc/network.h b/src/lxc/network.h
index 5db84058e8d62aec2b81ab048e9703aac773e5f2..14eff59faace54af43c37504da12ed566cc9b614 100644 (file)
--- a/src/lxc/network.h
+++ b/src/lxc/network.h
@@ -275,5 +275,7 @@ extern int lxc_requests_empty_network(struct lxc_handler *handler);
 extern int lxc_restore_phys_nics_to_netns(struct lxc_handler *handler);
 extern int lxc_setup_network_in_child_namespaces(const struct lxc_conf *conf,
                                                 struct lxc_list *network);
+extern int lxc_network_send_veth_names_to_child(struct lxc_handler *handler);
+extern int lxc_network_recv_veth_names_from_parent(struct lxc_handler *handler);
 
 #endif /* __LXC_NETWORK_H */

diff --git a/src/lxc/start.c b/src/lxc/start.c
index d077ff4b09db8344677747a65f4098fd3eebb1ad..ef0e0af98f76b06220ad287e848d1da1c17bc046 100644 (file)
--- a/src/lxc/start.c
+++ b/src/lxc/start.c
@@ -788,48 +788,6 @@ void lxc_abort(const char *name, struct lxc_handler *handler)
        }
 }
 
-/* netpipe is used in the unprivileged case to transfer the ifindexes from
- * parent to child
- */
-static int netpipe = -1;
-
-static inline int count_veths(struct lxc_list *network)
-{
-       struct lxc_list *iterator;
-       struct lxc_netdev *netdev;
-       int count = 0;
-
-       lxc_list_for_each(iterator, network) {
-               netdev = iterator->elem;
-               if (netdev->type != LXC_NET_VETH)
-                       continue;
-               count++;
-       }
-       return count;
-}
-
-static int read_unpriv_netifindex(struct lxc_list *network)
-{
-       struct lxc_list *iterator;
-       struct lxc_netdev *netdev;
-
-       if (netpipe == -1)
-               return 0;
-
-       lxc_list_for_each(iterator, network) {
-               netdev = iterator->elem;
-               if (netdev->type != LXC_NET_VETH)
-                       continue;
-
-               if (read(netpipe, netdev->name, IFNAMSIZ) != IFNAMSIZ) {
-                       close(netpipe);
-                       return -1;
-               }
-       }
-       close(netpipe);
-       return 0;
-}
-
 static int do_start(void *data)
 {
        struct lxc_list *iterator;
@@ -882,8 +840,10 @@ static int do_start(void *data)
        if (lxc_sync_barrier_parent(handler, LXC_SYNC_CONFIGURE))
                return -1;
 
-       if (read_unpriv_netifindex(&handler->conf->network) < 0)
+       if (lxc_network_recv_veth_names_from_parent(handler) < 0) {
+               ERROR("Failed to receive veth names from parent");
                goto out_warn_father;
+       }
 
        /* If we are in a new user namespace, become root there to have
         * privilege over our namespace.
@@ -1213,15 +1173,14 @@ void resolve_clone_flags(struct lxc_handler *handler)
  */
 static int lxc_spawn(struct lxc_handler *handler)
 {
-       int i, flags, nveths, ret;
+       int i, flags, ret;
        const char *name = handler->name;
        bool wants_to_map_ids;
-       int netpipepair[2], saved_ns_fd[LXC_NS_MAX];
+       int saved_ns_fd[LXC_NS_MAX];
        struct lxc_list *id_map;
        int failed_before_rename = 0, preserve_mask = 0;
        bool cgroups_connected = false;
 
-       netpipe = -1;
        id_map = &handler->conf->id_map;
        wants_to_map_ids = !lxc_list_empty(id_map);
 
@@ -1294,15 +1253,6 @@ static int lxc_spawn(struct lxc_handler *handler)
        if (attach_ns(handler->conf->inherit_ns_fd) < 0)
                goto out_delete_net;
 
-       if (!handler->root && (nveths = count_veths(&handler->conf->network))) {
-               if (pipe(netpipepair) < 0) {
-                       SYSERROR("Failed to create pipe.");
-                       goto out_delete_net;
-               }
-               /* Store netpipe in the global var for do_start's use. */
-               netpipe = netpipepair[0];
-       }
-
        /* Create a process in a new set of namespaces. */
        flags = handler->clone_flags;
        if (handler->clone_flags & CLONE_NEWUSER) {
@@ -1394,21 +1344,9 @@ static int lxc_spawn(struct lxc_handler *handler)
                }
        }
 
-       if (netpipe != -1) {
-               struct lxc_list *iterator;
-               struct lxc_netdev *netdev;
-
-               close(netpipe);
-               lxc_list_for_each(iterator, &handler->conf->network) {
-                       netdev = iterator->elem;
-                       if (netdev->type != LXC_NET_VETH)
-                               continue;
-                       if (write(netpipepair[1], netdev->name, IFNAMSIZ) != IFNAMSIZ) {
-                               ERROR("Error writing veth name to container.");
-                               goto out_delete_net;
-                       }
-               }
-               close(netpipepair[1]);
+       if (lxc_network_send_veth_names_to_child(handler) < 0) {
+               ERROR("Failed to send veth names to child");
+               goto out_delete_net;
        }
 
        /* Tell the child to continue its initialization. We'll get