automount: implement transient automounts

src/core/automount.c

@@ -1105,6 +1105,9 @@ const UnitVTable automount_vtable = {
         .reset_failed = automount_reset_failed,
 
         .bus_vtable = bus_automount_vtable,
+        .bus_set_property = bus_automount_set_property,
+
+        .can_transient = true,
 
         .shutdown = automount_shutdown,
         .supported = automount_supported,

src/core/dbus-automount.c

@@ -32,3 +32,57 @@ const sd_bus_vtable bus_automount_vtable[] = {
         SD_BUS_PROPERTY("TimeoutIdleUSec", "t", bus_property_get_usec, offsetof(Automount, timeout_idle_usec), SD_BUS_VTABLE_PROPERTY_CONST),
         SD_BUS_VTABLE_END
 };
+
+static int bus_automount_set_transient_property(
+                Automount *a,
+                const char *name,
+                sd_bus_message *message,
+                UnitSetPropertiesMode mode,
+                sd_bus_error *error) {
+
+        int r;
+
+        assert(a);
+        assert(name);
+        assert(message);
+
+        if (streq(name, "TimeoutIdleUSec")) {
+                usec_t timeout_idle_usec;
+                r = sd_bus_message_read(message, "t", &timeout_idle_usec);
+                if (r < 0)
+                        return r;
+
+                if (mode != UNIT_CHECK) {
+                        char time[FORMAT_TIMESPAN_MAX];
+
+                        a->timeout_idle_usec = timeout_idle_usec;
+                        unit_write_drop_in_format(UNIT(a), mode, name, "[Automount]\nTimeoutIdleSec=%s\n",
+                                format_timespan(time, sizeof(time), timeout_idle_usec, USEC_PER_MSEC));
+                }
+        } else
+                return 0;
+
+        return 1;
+}
+
+int bus_automount_set_property(
+                Unit *u,
+                const char *name,
+                sd_bus_message *message,
+                UnitSetPropertiesMode mode,
+                sd_bus_error *error) {
+
+        Automount *a = AUTOMOUNT(u);
+        int r = 0;
+
+        assert(a);
+        assert(name);
+        assert(message);
+
+        if (u->transient && u->load_state == UNIT_STUB)
+                /* This is a transient unit, let's load a little more */
+
+                r = bus_automount_set_transient_property(a, name, message, mode, error);
+
+        return r;
+}

src/core/dbus-automount.h

@@ -21,3 +21,5 @@
 
 
 extern const sd_bus_vtable bus_automount_vtable[];
+
+int bus_automount_set_property(Unit *u, const char *name, sd_bus_message *message, UnitSetPropertiesMode mode, sd_bus_error *error);