Add options to enable bus logging

This can be useful to find out what bus names your app
is actually talking to, so you can set up a bus policy
that is narrowed than blanket access without breaking
your application.

app/xdg-app-builtins-run.c

@@ -39,6 +39,8 @@ static char *opt_arch;
 static char *opt_branch;
 static char *opt_command;
 static gboolean opt_devel;
+static gboolean opt_log_session_bus;
+static gboolean opt_log_system_bus;
 static char *opt_runtime;
 static char *opt_runtime_version;
 
@@ -49,6 +51,8 @@ static GOptionEntry options[] = {
   { "devel", 'd', 0, G_OPTION_ARG_NONE, &opt_devel, "Use development runtime", NULL },
   { "runtime", 0, 0, G_OPTION_ARG_STRING, &opt_runtime, "Runtime to use", "RUNTIME" },
   { "runtime-version", 0, 0, G_OPTION_ARG_STRING, &opt_runtime_version, "Runtime version to use", "VERSION" },
+  { "log-session-bus", 0, 0, G_OPTION_ARG_NONE, &opt_log_session_bus, "Log session bus calls", NULL },
+  { "log-system-bus", 0, 0, G_OPTION_ARG_NONE, &opt_log_system_bus, "Log system bus calls", NULL },
   { NULL }
 };
 
@@ -105,7 +109,9 @@ xdg_app_builtin_run (int argc, char **argv, GCancellable *cancellable, GError **
                         arg_context,
                         opt_runtime,
                         opt_runtime_version,
-                        opt_devel ? XDG_APP_RUN_FLAG_DEVEL : 0,
+                        (opt_devel ? XDG_APP_RUN_FLAG_DEVEL : 0) |
+                        (opt_log_session_bus ? XDG_APP_RUN_FLAG_LOG_SESSION_BUS : 0) |
+                        (opt_log_system_bus ? XDG_APP_RUN_FLAG_LOG_SYSTEM_BUS : 0),
                         opt_command,
                         &argv[rest_argv_start + 1],
                         rest_argc - 1,

common/xdg-app-run.c

@@ -2120,6 +2120,7 @@ dbus_spawn_child_setup (gpointer user_data)
 static gboolean
 add_dbus_proxy_args (GPtrArray *argv_array,
                      GPtrArray *dbus_proxy_argv,
+                     gboolean   enable_logging,
                      GError **error)
 {
   int sync_proxy_pipes[2];
@@ -2136,6 +2137,8 @@ add_dbus_proxy_args (GPtrArray *argv_array,
 
   g_ptr_array_insert (dbus_proxy_argv, 0, g_strdup (DBUSPROXY));
   g_ptr_array_insert (dbus_proxy_argv, 1, g_strdup_printf ("--fd=%d", sync_proxy_pipes[1]));
+  if (enable_logging)
+    g_ptr_array_add (dbus_proxy_argv, g_strdup ("--log"));
 
   g_ptr_array_add (dbus_proxy_argv, NULL); /* NULL terminate */
 
@@ -2309,10 +2312,10 @@ xdg_app_run_app (const char *app_ref,
   if (!xdg_app_run_in_transient_unit (app_ref_parts[1], error))
     return FALSE;
 
-  if (!add_dbus_proxy_args (argv_array, session_bus_proxy_argv, error))
+  if (!add_dbus_proxy_args (argv_array, session_bus_proxy_argv, (flags & XDG_APP_RUN_FLAG_LOG_SESSION_BUS) != 0, error))
     return FALSE;
 
-  if (!add_dbus_proxy_args (argv_array, system_bus_proxy_argv, error))
+  if (!add_dbus_proxy_args (argv_array, system_bus_proxy_argv, (flags & XDG_APP_RUN_FLAG_LOG_SYSTEM_BUS) != 0,  error))
     return FALSE;
 
   app_files = xdg_app_deploy_get_files (app_deploy);

common/xdg-app-run.h

@@ -82,8 +82,10 @@ GFile *xdg_app_ensure_data_dir (const char *app_id,
 				GError **error);
 
 typedef enum {
-  XDG_APP_RUN_FLAG_DEVEL       = (1<<0),
-  XDG_APP_RUN_FLAG_BACKGROUND  = (1<<1),
+  XDG_APP_RUN_FLAG_DEVEL           = (1<<0),
+  XDG_APP_RUN_FLAG_BACKGROUND      = (1<<1),
+  XDG_APP_RUN_FLAG_LOG_SESSION_BUS = (1<<2),
+  XDG_APP_RUN_FLAG_LOG_SYSTEM_BUS  = (1<<3),
 } XdgAppRunFlags;
 
 gboolean xdg_app_run_app (const char *app_ref,