pkg/systemd: add dbus support

Move the dbus-connection code from libpod's healthcheck to pkg/systemd
to allow for sharing the logic.  Needed for the auto-updates work.

Signed-off-by: Valentin Rothberg <rothberg@redhat.com>

1 files changed, 47 insertions, 0 deletions

diff --git a/pkg/systemd/dbus.go b/pkg/systemd/dbus.go
new file mode 100644
index 000000000..df24667a1
--- /dev/null
+++ b/pkg/systemd/dbus.go
@@ -0,0 +1,47 @@
+package systemd
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+	"strconv"
+
+	"github.com/containers/libpod/pkg/rootless"
+	"github.com/coreos/go-systemd/v22/dbus"
+	godbus "github.com/godbus/dbus/v5"
+)
+
+func dbusAuthRootlessConnection(createBus func(opts ...godbus.ConnOption) (*godbus.Conn, error)) (*godbus.Conn, error) {
+	conn, err := createBus()
+	if err != nil {
+		return nil, err
+	}
+
+	methods := []godbus.Auth{godbus.AuthExternal(strconv.Itoa(rootless.GetRootlessUID()))}
+
+	err = conn.Auth(methods)
+	if err != nil {
+		conn.Close()
+		return nil, err
+	}
+
+	return conn, nil
+}
+
+func newRootlessConnection() (*dbus.Conn, error) {
+	return dbus.NewConnection(func() (*godbus.Conn, error) {
+		return dbusAuthRootlessConnection(func(opts ...godbus.ConnOption) (*godbus.Conn, error) {
+			path := filepath.Join(os.Getenv("XDG_RUNTIME_DIR"), "systemd/private")
+			return godbus.Dial(fmt.Sprintf("unix:path=%s", path))
+		})
+	})
+}
+
+// ConnectToDBUS returns a DBUS connection.  It works both as root and non-root
+// users.
+func ConnectToDBUS() (*dbus.Conn, error) {
+	if rootless.IsRootless() {
+		return newRootlessConnection()
+	}
+	return dbus.NewSystemdConnection()
+}