lxc-checkpoint: automatically detect if --external or --veth-pair

With the criu release 2.8 criu deprecated the --veth-pair command-line
option in favor of --external:

f2037e6 veth: Make --external support --veth-pair

git tag --contains f2037e6d3445fc400
v2.8

With this commit lxc-checkpoint will automatically switch between
the new and old command-line option dependent on the detected
criu version.

For criu version older than 2.8 something like this will be used:

  --veth-pair eth0=vethYOK6RW@lxcbr0

and starting with criu version 2.8 it will look like this:

  --external veth[eth0]:vethCRPEYL@lxcbr0

Signed-off-by: Adrian Reber <areber@redhat.com>

diff --git a/src/lxc/criu.c b/src/lxc/criu.c
index 9523af3b41f8a88a59ef3d5b71f4fbbb54b3d1d6..50a74000d8bf8f0d81faf0cf996aa096a8eaf39c 100644 (file)
--- a/src/lxc/criu.c
+++ b/src/lxc/criu.c
@@ -58,6 +58,7 @@
 #define CRIU_GITID_PATCHLEVEL  0
 
 #define CRIU_IN_FLIGHT_SUPPORT "2.4"
+#define CRIU_EXTERNAL_NOT_VETH "2.8"
 
 lxc_log_define(lxc_criu, lxc);
 
@@ -482,7 +483,19 @@ static void exec_criu(struct criu_opts *opts)
 
                lxc_list_for_each(it, &opts->c->lxc_conf->network) {
                        char eth[128], *veth;
+                       char *fmt;
                        struct lxc_netdev *n = it->elem;
+                       bool external_not_veth;
+
+                       if (strcmp(opts->criu_version, CRIU_EXTERNAL_NOT_VETH) >= 0) {
+                               /* Since criu version 2.8 the usage of --veth-pair
+                                * has been deprecated:
+                                * git tag --contains f2037e6d3445fc400
+                                * v2.8 */
+                               external_not_veth = true;
+                       } else {
+                               external_not_veth = false;
+                       }
 
                        if (n->name) {
                                if (strlen(n->name) >= sizeof(eth))
@@ -498,10 +511,21 @@ static void exec_criu(struct criu_opts *opts)
                        case LXC_NET_VETH:
                                veth = n->priv.veth_attr.pair;
 
-                               if (n->link)
-                                       ret = snprintf(buf, sizeof(buf), "veth[%s]:%s@%s", eth, veth, n->link);
-                               else
-                                       ret = snprintf(buf, sizeof(buf), "veth[%s]:%s", eth, veth);
+                               if (n->link) {
+                                       if (external_not_veth)
+                                               fmt = "veth[%s]:%s@%s";
+                                       else
+                                               fmt = "%s=%s@%s";
+
+                                       ret = snprintf(buf, sizeof(buf), fmt, eth, veth, n->link);
+                               } else {
+                                       if (external_not_veth)
+                                               fmt = "veth[%s]:%s";
+                                       else
+                                               fmt = "%s=%s";
+
+                                       ret = snprintf(buf, sizeof(buf), fmt, eth, veth);
+                               }
                                if (ret < 0 || ret >= sizeof(buf))
                                        goto err;
                                break;
@@ -524,7 +548,10 @@ static void exec_criu(struct criu_opts *opts)
                                goto err;
                        }
 
-                       DECLARE_ARG("--external");
+                       if (external_not_veth)
+                               DECLARE_ARG("--external");
+                       else
+                               DECLARE_ARG("--veth-pair");
                        DECLARE_ARG(buf);
                        netnr++;
                }