tree-wide: install matches asynchronously

Let's remove a number of synchronization points from our service
startups: let's drop synchronous match installation, and let's opt for
asynchronous instead.

Also, let's use sd_bus_match_signal() instead of sd_bus_add_match()
where we can.

3 files changed, 53 insertions, 56 deletions

diff --git a/src/libelogind/sd-bus/bus-track.c b/src/libelogind/sd-bus/bus-track.c
index ab22d6e4d..919cebda0 100644
--- a/src/libelogind/sd-bus/bus-track.c
+++ b/src/libelogind/sd-bus/bus-track.c
@@ -259,9 +259,7 @@ _public_ int sd_bus_track_add_name(sd_bus_track *track, const char *name) {
 
         bus_track_remove_from_queue(track); /* don't dispatch this while we work in it */
 
-        track->n_adding++; /* make sure we aren't dispatched while we synchronously add this match */
-        r = sd_bus_add_match(track->bus, &n->slot, match, on_name_owner_changed, track);
-        track->n_adding--;
+        r = sd_bus_add_match_async(track->bus, &n->slot, match, on_name_owner_changed, NULL, track);
         if (r < 0) {
                 bus_track_add_to_queue(track);
                 return r;
diff --git a/src/login/logind.c b/src/login/logind.c
index c030531c3..2f7243ba2 100644
--- a/src/login/logind.c
+++ b/src/login/logind.c
@@ -727,48 +727,49 @@ static int manager_connect_bus(Manager *m) {
                 return log_error_errno(r, "Failed to add user enumerator: %m");
 
 #if 0 /// elogind does not support systemd as PID 1
-        r = sd_bus_add_match(m->bus,
-                             NULL,
-                             "type='signal',"
-                             "sender='org.freedesktop.systemd1',"
-                             "interface='org.freedesktop.systemd1.Manager',"
-                             "member='JobRemoved',"
-                             "path='/org/freedesktop/systemd1'",
-                             match_job_removed, m);
+        r = sd_bus_match_signal_async(
+                        m->bus,
+                        NULL,
+                        "org.freedesktop.systemd1",
+                        "/org/freedesktop/systemd1",
+                        "org.freedesktop.systemd1.Manager",
+                        "JobRemoved",
+                        match_job_removed, NULL, m);
         if (r < 0)
-                return log_error_errno(r, "Failed to add match for JobRemoved: %m");
-
-        r = sd_bus_add_match(m->bus,
-                             NULL,
-                             "type='signal',"
-                             "sender='org.freedesktop.systemd1',"
-                             "interface='org.freedesktop.systemd1.Manager',"
-                             "member='UnitRemoved',"
-                             "path='/org/freedesktop/systemd1'",
-                             match_unit_removed, m);
+                return log_error_errno(r, "Failed to request match for JobRemoved: %m");
+
+        r = sd_bus_match_signal_async(
+                        m->bus,
+                        NULL,
+                        "org.freedesktop.systemd1",
+                        "/org/freedesktop/systemd1",
+                        "org.freedesktop.systemd1.Manager",
+                        "UnitRemoved",
+                        match_unit_removed, NULL, m);
         if (r < 0)
-                return log_error_errno(r, "Failed to add match for UnitRemoved: %m");
-
-        r = sd_bus_add_match(m->bus,
-                             NULL,
-                             "type='signal',"
-                             "sender='org.freedesktop.systemd1',"
-                             "interface='org.freedesktop.DBus.Properties',"
-                             "member='PropertiesChanged'",
-                             match_properties_changed, m);
+                return log_error_errno(r, "Failed to request match for UnitRemoved: %m");
+
+        r = sd_bus_match_signal_async(
+                        m->bus,
+                        NULL,
+                        "org.freedesktop.systemd1",
+                        NULL,
+                        "org.freedesktop.DBus.Properties",
+                        "PropertiesChanged",
+                        match_properties_changed, NULL, m);
         if (r < 0)
-                return log_error_errno(r, "Failed to add match for PropertiesChanged: %m");
-
-        r = sd_bus_add_match(m->bus,
-                             NULL,
-                             "type='signal',"
-                             "sender='org.freedesktop.systemd1',"
-                             "interface='org.freedesktop.systemd1.Manager',"
-                             "member='Reloading',"
-                             "path='/org/freedesktop/systemd1'",
-                             match_reloading, m);
+                return log_error_errno(r, "Failed to request match for PropertiesChanged: %m");
+
+        r = sd_bus_match_signal_async(
+                        m->bus,
+                        NULL,
+                        "org.freedesktop.systemd1",
+                        "/org/freedesktop/systemd1",
+                        "org.freedesktop.systemd1.Manager",
+                        "Reloading",
+                        match_reloading, NULL, m);
         if (r < 0)
-                return log_error_errno(r, "Failed to add match for Reloading: %m");
+                return log_error_errno(r, "Failed to request match for Reloading: %m");
 
         r = sd_bus_call_method(
                         m->bus,
diff --git a/src/shared/bus-util.c b/src/shared/bus-util.c
index eb953b9bb..1f9aa8dbe 100644
--- a/src/shared/bus-util.c
+++ b/src/shared/bus-util.c
@@ -69,7 +69,7 @@ static int name_owner_change_callback(sd_bus_message *m, void *userdata, sd_bus_
 }
 
 int bus_async_unregister_and_exit(sd_event *e, sd_bus *bus, const char *name) {
-        _cleanup_free_ char *match = NULL;
+        const char *match;
         const char *unique;
         int r;
 
@@ -86,23 +86,21 @@ int bus_async_unregister_and_exit(sd_event *e, sd_bus *bus, const char *name) {
         if (r < 0)
                 return r;
 
-        r = asprintf(&match,
-                     "sender='org.freedesktop.DBus',"
-                     "type='signal',"
-                     "interface='org.freedesktop.DBus',"
-                     "member='NameOwnerChanged',"
-                     "path='/org/freedesktop/DBus',"
-                     "arg0='%s',"
-                     "arg1='%s',"
-                     "arg2=''", name, unique);
-        if (r < 0)
-                return -ENOMEM;
-
-        r = sd_bus_add_match(bus, NULL, match, name_owner_change_callback, e);
+        match = strjoina(
+                        "sender='org.freedesktop.DBus',"
+                        "type='signal',"
+                        "interface='org.freedesktop.DBus',"
+                        "member='NameOwnerChanged',"
+                        "path='/org/freedesktop/DBus',"
+                        "arg0='", name, "',",
+                        "arg1='", unique, "',",
+                        "arg2=''");
+
+        r = sd_bus_add_match_async(bus, NULL, match, name_owner_change_callback, NULL, e);
         if (r < 0)
                 return r;
 
-        r = sd_bus_release_name(bus, name);
+        r = sd_bus_release_name_async(bus, NULL, name, NULL, NULL);
         if (r < 0)
                 return r;