core: add flag to nm_shutdown_wait_obj_register_full() for freeing allcated message string

In fact, nm_shutdown_wait_obj_register*() API is still not implemented
and registering an object has no effect currently. That is, blocking
shutdown and waiting for instances to be destroyed during shutdown
is not yet implemented. Still, we already implement the API so that
components can register themself to block the shutdown. The point is
of course, that the callers already use this API, although it's not yet
implemented.

Anyway, sometimes the message string is not static. Add an option to
pass an allocated string and let the string be destroyed when no longer
needed.

2 files changed, 25 insertions, 16 deletions

diff --git a/src/NetworkManagerUtils.c b/src/NetworkManagerUtils.c
index a070d50c2a..3618e32f51 100644
--- a/src/NetworkManagerUtils.c
+++ b/src/NetworkManagerUtils.c
@@ -959,7 +959,8 @@ nm_ip_routing_rule_to_platform (const NMIPRoutingRule *rule,
 struct _NMShutdownWaitObjHandle {
 	CList lst;
 	GObject *watched_obj;
-	const char *msg_reason;
+	char *msg_reason;
+	bool free_msg_reason:1;
 };
 
 static CList _shutdown_waitobj_lst_head;
@@ -968,6 +969,8 @@ static void
 _shutdown_waitobj_unregister (NMShutdownWaitObjHandle *handle)
 {
 	c_list_unlink_stale (&handle->lst);
+	if (handle->free_msg_reason)
+		g_free (handle->msg_reason);
 	g_slice_free (NMShutdownWaitObjHandle, handle);
 
 	/* FIXME(shutdown): check whether the object list is empty, and
@@ -986,13 +989,14 @@ _shutdown_waitobj_cb (gpointer user_data,
 }
 
 /**
- * _nm_shutdown_wait_obj_register:
+ * nm_shutdown_wait_obj_register_full:
  * @watched_obj: the object to watch. Takes a weak reference on the object
  *   to be notified when it gets destroyed.
- * @msg_reason: a reason message, for debugging and logging purposes. It
- *   must be a static string. Or at least, be alive at least as long as
- *   @watched_obj. So, theoretically, if you need a dynamic @msg_reason,
- *   you could attach it to @watched_obj's user-data.
+ * @msg_reason: a reason message, for debugging and logging purposes.
+ * @free_msg_reason: if %TRUE, then ownership of @msg_reason will be taken
+ *   and the string will be freed with g_free() afterwards. If %FALSE,
+ *   the caller must ensure that @msg_reason string outlives the watched
+ *   objects (e.g. being a static strings).
  *
  * Keep track of @watched_obj until it gets destroyed. During shutdown,
  * we wait until all watched objects are destroyed. This is useful, if
@@ -1009,8 +1013,9 @@ _shutdown_waitobj_cb (gpointer user_data,
  *   once it gets destroyed.
  */
 NMShutdownWaitObjHandle *
-_nm_shutdown_wait_obj_register (GObject *watched_obj,
-                                const char *msg_reason)
+nm_shutdown_wait_obj_register_full (GObject *watched_obj,
+                                    char *msg_reason,
+                                    gboolean free_msg_reason)
 {
 	NMShutdownWaitObjHandle *handle;
 
@@ -1020,11 +1025,14 @@ _nm_shutdown_wait_obj_register (GObject *watched_obj,
 		c_list_init (&_shutdown_waitobj_lst_head);
 
 	handle = g_slice_new (NMShutdownWaitObjHandle);
-	handle->watched_obj = watched_obj;
-	/* we don't clone the string. We require the caller to use pass a static message.
-	 * If he really cannot do that, he should attach the string to the watched_obj
-	 * as user-data. */
-	handle->msg_reason = msg_reason;
+	*handle = (NMShutdownWaitObjHandle) {
+		/* depending on @free_msg_reason, we take ownership of @msg_reason.
+		 * In either case, we just reference the string without cloning
+		 * it. */
+		.watched_obj     = watched_obj,
+		.msg_reason      = msg_reason,
+		.free_msg_reason = free_msg_reason,
+	};
 	c_list_link_tail (&_shutdown_waitobj_lst_head, &handle->lst);
 	g_object_weak_ref (watched_obj, _shutdown_waitobj_cb, handle);
 	return handle;
diff --git a/src/NetworkManagerUtils.h b/src/NetworkManagerUtils.h
index 5e3f6673c4..778dc00176 100644
--- a/src/NetworkManagerUtils.h
+++ b/src/NetworkManagerUtils.h
@@ -89,10 +89,11 @@ NMPlatformRoutingRule *nm_ip_routing_rule_to_platform (const NMIPRoutingRule *ru
 
 typedef struct _NMShutdownWaitObjHandle NMShutdownWaitObjHandle;
 
-NMShutdownWaitObjHandle *_nm_shutdown_wait_obj_register (GObject *watched_obj,
-                                                        const char *msg_reason);
+NMShutdownWaitObjHandle *nm_shutdown_wait_obj_register_full (GObject *watched_obj,
+                                                             char *msg_reason,
+                                                             gboolean free_msg_reason);
 
-#define nm_shutdown_wait_obj_register(watched_obj, msg_reason) _nm_shutdown_wait_obj_register((watched_obj), (""msg_reason""))
+#define nm_shutdown_wait_obj_register(watched_obj, msg_reason) nm_shutdown_wait_obj_register_full((watched_obj), (""msg_reason""), FALSE)
 
 void nm_shutdown_wait_obj_unregister (NMShutdownWaitObjHandle *handle);