[gvfs/wip/oholy/flatpak-assertions: 14/14] backend: Prevent usage of NULL

[Ondrej Holy <oholy src gnome org>]

commit d1ab5870e828df259897598298c2ca66b587426a
Author: Ondrej Holy <oholy redhat com>
Date:   Wed Aug 29 15:36:57 2018 +0200

    backend: Prevent usage of NULL
    
    g_dbus_connection_get_peer_credentials may fail in some cases, see
    the documentation, and thus we have to check the return value before
    use in order to prevent warnings like the following:
    
    g_credentials_get_unix_pid: assertion 'G_IS_CREDENTIALS (credentials)' failed
    
    Print simply -1 if pid can't be obtained this way.

 daemon/gvfsbackend.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)
---
diff --git a/daemon/gvfsbackend.c b/daemon/gvfsbackend.c
index 673070fa..4fd3455c 100644
--- a/daemon/gvfsbackend.c
+++ b/daemon/gvfsbackend.c
@@ -609,14 +609,17 @@ g_vfs_backend_invocation_first_handler (GVfsDBusMount *object,
 {
   GDBusConnection *connection;
   GCredentials *credentials;
+  pid_t pid = -1;
 
   connection = g_dbus_method_invocation_get_connection (invocation);
   credentials = g_dbus_connection_get_peer_credentials (connection);
+  if (credentials)
+    pid = g_credentials_get_unix_pid (credentials, NULL);
 
-  g_debug ("backend_dbus_handler %s:%s (pid=%u)\n",
+  g_debug ("backend_dbus_handler %s:%s (pid=%ld)\n",
            g_dbus_method_invocation_get_interface_name (invocation),
            g_dbus_method_invocation_get_method_name (invocation),
-           g_credentials_get_unix_pid (credentials, NULL));
+           (long)pid);
 
   if (backend->priv->block_requests)
     {