First, are you actually switching your bus connection to monitor mode? In kdbus (and probably even in future DBus) there is a distinct monitor mode which must be enabled to capture other peers' bus traffic. Adding a match is not enough for that. Second, your approach won't work anyway. There *won't be* method_calls for services that are started as dependencies, there won't be method calls for socket-activated services, there won't be method calls for DBus-activated services, there probably won't be even a single Start call during the entire boot process. Systemd won't bother calling itself over DBus for that. Instead, why not use the *signals* that systemd sends, for exactly such purposes? You'll need to call Subscribe() to enable them. See also what Plymouth does for its splash screen. <div class="gmail_quote"><div dir="ltr">On Tue, Jun 30, 2015, 12:15 Thomas Schmidt <<a href="mailto:t.schmidt@md-network.de" target="_blank">t.schmidt@md-network.de</a>> wrote: </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Hello, for an embedded project I’m implementing a bootsplash application which should as well display service names are starting. This is based on kdbus and uses the sd-bus API to communicate with systemd (for example boot process percentage property is polled). Now I try to monitor the kdbus (system bus) to capture the events which indicate that a service was started. (works very well for testing with "busctl monitor“ tool). I assumed that the method_call „StartUnit“ would be a good indicator, so I tried to monitor for those messages by using following code (shortened and only significant parts copied here): -.-.-.-.-.-.-.-.-.-.-. schnipp -.-.-.-.-.-.-.-.-.-.- r = sd_bus_open_system(&bus); … r = sd_bus_add_match(bus, NULL, "", do_something_callback, NULL); /* should not filter anything, I expect it triggers on any message */ … for (;;) { sd_bus_message *m = NULL; r = sd_bus_process(bus, &m); if (r < 0) { fprintf(stderr, "Failed to process bus: %s\n", strerror(-r)); goto finish; } if (r > 0) /* we processed a request, try to process another one, right-away */ continue; /* Wait for the next request to process */ r = sd_bus_wait(bus, (uint64_t) -1); if (r < 0) { fprintf(stderr, "Failed to wait on bus: %s\n", strerror(-r)); goto finish; } } … -.-.-.-.-.-.-.-.-.-.-. schnapp -.-.-.-.-.-.-.-.-.-.- The interesting thing is that this code only sees „signal“ type messages - but not any other like „method_call“. I did extensive testing, tried different code variants, for example by processing "sd_bus_message *m“ directly in the for loop with „sd_bus_message_is_method_call“ - but the effect is the same I don’t get „method_call“ as an event. Is there any suggestion what could be the reason ? (is that generally the right way what I try here to do ?) Many thanks for any feedback which points me to the right direction Kind Regards Thomas Schmidt _______________________________________________ systemd-devel mailing list <a href="mailto:systemd-devel@lists.freedesktop.org" target="_blank">systemd-devel@lists.freedesktop.org</a> <a href="http://lists.freedesktop.org/mailman/listinfo/systemd-devel" rel="noreferrer" target="_blank">http://lists.freedesktop.org/mailman/listinfo/systemd-devel</a> </blockquote></div>