From 13a21efd28777ddfe7578ec7506e98d248878e67 Mon Sep 17 00:00:00 2001
From: Paul Holzinger <pholzing@redhat.com>
Date: Mon, 9 Dec 2024 14:01:21 +0100
Subject: [PATCH] libnetwork/netavark: do not create config dir in init

Podman creates/initializes the network backend for every command. However
most commands will not need it so we should keep the required actions we
do to a minimum.

In this case the config directory /etc/containers/networks by default as
root may not exists and then we try to create it which can fail, i.e.
when /etc is read only[1].

The code here are a bit more changes then I would have liked but we must
make sure the default in memory network always exists and do not create
the directory there.

[1] https://github.com/containers/common/pull/2265

Signed-off-by: Paul Holzinger <pholzing@redhat.com>
---
 libnetwork/netavark/config.go  |  3 +++
 libnetwork/netavark/network.go | 19 +++++++++++++++----
 2 files changed, 18 insertions(+), 4 deletions(-)

diff --git a/libnetwork/netavark/config.go b/libnetwork/netavark/config.go
index 33ef26acf..3305258b6 100644
--- a/libnetwork/netavark/config.go
+++ b/libnetwork/netavark/config.go
@@ -30,6 +30,9 @@ func sliceRemoveDuplicates(strList []string) []string {
 }
 
 func (n *netavarkNetwork) commitNetwork(network *types.Network) error {
+	if err := os.MkdirAll(n.networkConfigDir, 0o755); err != nil {
+		return nil
+	}
 	confPath := filepath.Join(n.networkConfigDir, network.Name+".json")
 	f, err := os.Create(confPath)
 	if err != nil {
diff --git a/libnetwork/netavark/network.go b/libnetwork/netavark/network.go
index 6ec4a9d15..985d0db2d 100644
--- a/libnetwork/netavark/network.go
+++ b/libnetwork/netavark/network.go
@@ -135,10 +135,6 @@ func NewNetworkInterface(conf *InitConfig) (types.ContainerNetwork, error) {
 		return nil, fmt.Errorf("failed to parse default subnet: %w", err)
 	}
 
-	if err := os.MkdirAll(conf.NetworkConfigDir, 0o755); err != nil {
-		return nil, err
-	}
-
 	if err := os.MkdirAll(conf.NetworkRunDir, 0o755); err != nil {
 		return nil, err
 	}
@@ -187,6 +183,21 @@ func (n *netavarkNetwork) loadNetworks() error {
 	// check the mod time of the config dir
 	f, err := os.Stat(n.networkConfigDir)
 	if err != nil {
+		// the directory may not exists which is fine. It will be created on the first network create
+		if errors.Is(err, os.ErrNotExist) {
+			// networks are already loaded
+			if n.networks != nil {
+				return nil
+			}
+			networks := make(map[string]*types.Network, 1)
+			networkInfo, err := n.createDefaultNetwork()
+			if err != nil {
+				return fmt.Errorf("failed to create default network %s: %w", n.defaultNetwork, err)
+			}
+			networks[n.defaultNetwork] = networkInfo
+			n.networks = networks
+			return nil
+		}
 		return err
 	}
 	modTime := f.ModTime()