confile_legacy: fix legacy network parser

src/lxc/confile_legacy.c

@@ -154,6 +154,53 @@ int set_config_network_legacy(const char *key, const char *value,
 	return lxc_clear_config_network(lxc_conf);
 }
 
+/*
+ * If you have p="lxc.network.0.link", pass it p+12
+ * to get back '0' (the index of the nic).
+ */
+static int get_network_netdev_idx(const char *key)
+{
+	int ret, idx;
+
+	if (*key < '0' || *key > '9')
+		return EINVAL;
+
+	ret = sscanf(key, "%d", &idx);
+	if (ret != 1)
+		return EINVAL;
+
+	/* Since we've implemented the new network parser legacy networks are
+	 * recorded using a negative index starting from -1. To preserve the old
+	 * behavior we need this function to return the appropriate negative
+	 * index.
+	 */
+	return -(++idx);
+}
+
+/*
+ * If you have p="lxc.network.0", pass this p+12 and it will return
+ * the netdev of the first configured nic.
+ */
+static struct lxc_netdev *get_netdev_from_key(const char *key,
+					      struct lxc_list *network)
+{
+	int idx;
+	struct lxc_list *it;
+	struct lxc_netdev *netdev = NULL;
+
+	idx = get_network_netdev_idx(key);
+	if (idx == EINVAL)
+		return NULL;
+
+	lxc_list_for_each(it, network) {
+		netdev = it->elem;
+		if (idx == netdev->idx)
+			return netdev;
+	}
+
+	return NULL;
+}
+
 int set_config_network_legacy_type(const char *key, const char *value,
 				   struct lxc_conf *lxc_conf, void *data)
 {
@@ -164,6 +211,12 @@ int set_config_network_legacy_type(const char *key, const char *value,
 	if (lxc_config_value_empty(value))
 		return lxc_clear_config_network(lxc_conf);
 
+	netdev = get_netdev_from_key(key + 12, network);
+	if (netdev) {
+		ERROR("Network already exists");
+		return -EEXIST;
+	}
+
 	netdev = malloc(sizeof(*netdev));
 	if (!netdev) {
 		SYSERROR("failed to allocate memory");
@@ -187,7 +240,7 @@ int set_config_network_legacy_type(const char *key, const char *value,
 	/* We maintain a negative count for legacy networks. */
 	netdev->idx = -1;
 	if (!lxc_list_empty(network)) {
-		prevnetdev = lxc_list_last_elem(network);
+		prevnetdev = lxc_list_first_elem(network);
 		netdev->idx = prevnetdev->idx;
 		if (netdev->idx == INT_MIN) {
 			ERROR("number of requested networks would underflow "
@@ -199,7 +252,7 @@ int set_config_network_legacy_type(const char *key, const char *value,
 		netdev->idx--;
 	}
 
-	lxc_list_add_tail(network, list);
+	lxc_list_add(network, list);
 
 	if (!strcmp(value, "veth"))
 		netdev->type = LXC_NET_VETH;
@@ -221,53 +274,6 @@ int set_config_network_legacy_type(const char *key, const char *value,
 	return 0;
 }
 
-/*
- * If you have p="lxc.network.0.link", pass it p+12
- * to get back '0' (the index of the nic).
- */
-static int get_network_netdev_idx(const char *key)
-{
-	int ret, idx;
-
-	if (*key < '0' || *key > '9')
-		return EINVAL;
-
-	ret = sscanf(key, "%d", &idx);
-	if (ret != 1)
-		return EINVAL;
-
-	/* Since we've implemented the new network parser legacy networks are
-	 * recorded using a negative index starting from -1. To preserve the old
-	 * behavior we need this function to return the appropriate negative
-	 * index.
-	 */
-	return -(++idx);
-}
-
-/*
- * If you have p="lxc.network.0", pass this p+12 and it will return
- * the netdev of the first configured nic.
- */
-static struct lxc_netdev *get_netdev_from_key(const char *key,
-					      struct lxc_list *network)
-{
-	int idx;
-	struct lxc_list *it;
-	struct lxc_netdev *netdev = NULL;
-
-	idx = get_network_netdev_idx(key);
-	if (idx == EINVAL)
-		return NULL;
-
-	lxc_list_for_each(it, network) {
-		netdev = it->elem;
-		if (idx == netdev->idx)
-			return netdev;
-	}
-
-	return NULL;
-}
-
 int lxc_list_nicconfigs_legacy(struct lxc_conf *c, const char *key, char *retv,
 			       int inlen)
 {
@@ -328,7 +334,7 @@ static struct lxc_netdev *network_netdev(const char *key, const char *value,
 	}
 
 	if (get_network_netdev_idx(key + 12) == EINVAL)
-		netdev = lxc_list_last_elem(network);
+		netdev = lxc_list_first_elem(network);
 	else
 		netdev = get_netdev_from_key(key + 12, network);
 
@@ -958,7 +964,7 @@ static int lxc_clear_nic(struct lxc_conf *c, const char *key)
 	}
 
 	if ((idx = get_network_netdev_idx(key)) == EINVAL)
-		netdev = lxc_list_last_elem(&c->network);
+		netdev = lxc_list_first_elem(&c->network);
 	else {
 		lxc_list_for_each(it, &c->network) {
 			netdev = it->elem;