cmd: allow import/running ctrld as library

cmd/cli/network_manager_linux.go

@@ -0,0 +1,76 @@
+package cli
+
+import (
+	"context"
+	"os"
+	"path/filepath"
+	"time"
+
+	"github.com/coreos/go-systemd/v22/dbus"
+)
+
+const (
+	nmConfDir           = "/etc/NetworkManager/conf.d"
+	nmCtrldConfFilename = "99-ctrld.conf"
+	nmCtrldConfContent  = `[main]
+dns=none
+systemd-resolved=false
+`
+	nmSystemdUnitName   = "NetworkManager.service"
+	systemdEnabledState = "enabled"
+)
+
+var networkManagerCtrldConfFile = filepath.Join(nmConfDir, nmCtrldConfFilename)
+
+func setupNetworkManager() error {
+	if content, _ := os.ReadFile(nmCtrldConfContent); string(content) == nmCtrldConfContent {
+		mainLog.Load().Debug().Msg("NetworkManager already setup, nothing to do")
+		return nil
+	}
+	err := os.WriteFile(networkManagerCtrldConfFile, []byte(nmCtrldConfContent), os.FileMode(0644))
+	if os.IsNotExist(err) {
+		mainLog.Load().Debug().Msg("NetworkManager is not available")
+		return nil
+	}
+	if err != nil {
+		mainLog.Load().Debug().Err(err).Msg("could not write NetworkManager ctrld config file")
+		return err
+	}
+
+	reloadNetworkManager()
+	mainLog.Load().Debug().Msg("setup NetworkManager done")
+	return nil
+}
+
+func restoreNetworkManager() error {
+	err := os.Remove(networkManagerCtrldConfFile)
+	if os.IsNotExist(err) {
+		mainLog.Load().Debug().Msg("NetworkManager is not available")
+		return nil
+	}
+	if err != nil {
+		mainLog.Load().Debug().Err(err).Msg("could not remove NetworkManager ctrld config file")
+		return err
+	}
+
+	reloadNetworkManager()
+	mainLog.Load().Debug().Msg("restore NetworkManager done")
+	return nil
+}
+
+func reloadNetworkManager() {
+	ctx, cancel := context.WithTimeout(context.Background(), time.Second*10)
+	defer cancel()
+	conn, err := dbus.NewSystemConnectionContext(ctx)
+	if err != nil {
+		mainLog.Load().Error().Err(err).Msg("could not create new system connection")
+		return
+	}
+	defer conn.Close()
+
+	waitCh := make(chan string)
+	if _, err := conn.ReloadUnitContext(ctx, nmSystemdUnitName, "ignore-dependencies", waitCh); err != nil {
+		mainLog.Load().Debug().Err(err).Msg("could not reload NetworkManager")
+	}
+	<-waitCh
+}