bus: add sd_bus_track object for tracking peers, and port core over to it

This is primarily useful for services that need to track clients which
reference certain objects they maintain, or which explicitly want to
subscribe to certain events. Something like this is done in a large
number of services, and not trivial to do. Hence, let's unify this at
one place.

This also ports over PID 1 to use this to ensure that subscriptions to
job and manager events are correctly tracked. As a side-effect this
makes sure we properly serialize and restore the track list across
daemon reexec/reload, which didn't work correctly before.

This also simplifies how we distribute messages to broadcast to the
direct busses: we only track subscriptions for the API bus and
implicitly assume that all direct busses are subscribed. This should be
a pretty OK simplification since clients connected via direct bus
connections are shortlived anyway.

1 files changed, 0 insertions, 2 deletions

diff --git a/src/core/dbus-manager.h b/src/core/dbus-manager.h
index 0ef99fad41..e1903fa16a 100644
--- a/src/core/dbus-manager.h
+++ b/src/core/dbus-manager.h
@@ -26,7 +26,5 @@
 
 extern const sd_bus_vtable bus_manager_vtable[];
 
-int bus_manager_foreach_client(Manager *m, int (*send_message)(sd_bus *bus, const char *destination, void *userdata), void *userdata);
-
 void bus_manager_send_finished(Manager *m, usec_t firmware_usec, usec_t loader_usec, usec_t kernel_usec, usec_t initrd_usec, usec_t userspace_usec, usec_t total_usec);
 void bus_manager_send_reloading(Manager *m, bool active);