[lxc-devel] [PATCH v2] pass on reboot flag and delete old veth on reboot

[Wolfgang Bumiller]

When setting lxc.network.veth.pair to get a fixed interface
name the recreation of it after a reboot caused an EEXIST.
-) The reboot flag is now a three-state value. It's set to
1 to request a reboot, and 2 during a reboot until after
lxc_spawn where it is reset to 0.
-) If the reboot is set (!= 0) within instantiate_veth and
a fixed name is used, the interface is now deleted before
being recreated.

Signed-off-by: Wolfgang Bumiller <w.bumiller at proxmox.com>
---
 src/lxc/conf.c         | 6 ++++--
 src/lxc/lxccontainer.c | 6 +++---
 src/lxc/start.c        | 2 ++
 3 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/src/lxc/conf.c b/src/lxc/conf.c
index 9870455..ed2ad66 100644
--- a/src/lxc/conf.c
+++ b/src/lxc/conf.c
@@ -2613,9 +2613,11 @@ static int instantiate_veth(struct lxc_handler *handler, struct lxc_netdev *netd
 	char veth2buf[IFNAMSIZ], *veth2;
 	int err;
 
-	if (netdev->priv.veth_attr.pair)
+	if (netdev->priv.veth_attr.pair) {
 		veth1 = netdev->priv.veth_attr.pair;
-	else {
+		if (handler->conf->reboot)
+			lxc_netdev_delete_by_name(veth1);
+	} else {
 		err = snprintf(veth1buf, sizeof(veth1buf), "vethXXXXXX");
 		if (err >= sizeof(veth1buf)) { /* can't *really* happen, but... */
 			ERROR("veth1 name too long");
diff --git a/src/lxc/lxccontainer.c b/src/lxc/lxccontainer.c
index 1c103e8..223e78e 100644
--- a/src/lxc/lxccontainer.c
+++ b/src/lxc/lxccontainer.c
@@ -760,9 +760,9 @@ static bool do_lxcapi_start(struct lxc_container *c, int useinit, char * const a
 		pid_fp = NULL;
 	}
 
-reboot:
 	conf->reboot = 0;
 
+reboot:
 	if (lxc_check_inherited(conf, daemonize, -1)) {
 		ERROR("Inherited fds found");
 		ret = 1;
@@ -772,9 +772,9 @@ reboot:
 	ret = lxc_start(c->name, argv, conf, c->config_path, daemonize);
 	c->error_num = ret;
 
-	if (conf->reboot) {
+	if (conf->reboot == 1) {
 		INFO("container requested reboot");
-		conf->reboot = 0;
+		conf->reboot = 2;
 		goto reboot;
 	}
 
diff --git a/src/lxc/start.c b/src/lxc/start.c
index 6eded61..2fc026e 100644
--- a/src/lxc/start.c
+++ b/src/lxc/start.c
@@ -1173,6 +1173,8 @@ int __lxc_start(const char *name, struct lxc_conf *conf,
 		goto out_detach_blockdev;
 	}
 
+	handler->conf->reboot = 0;
+
 	netnsfd = get_netns_fd(handler->pid);
 
 	err = lxc_poll(name, handler);
-- 
2.1.4