sd-bus: add API to query which handler/callback is currently being dispatched

5 files changed, 74 insertions, 2 deletions

diff --git a/src/libsystemd/sd-bus/bus-internal.h b/src/libsystemd/sd-bus/bus-internal.h
index 618e82c98f..f2ccdfd177 100644
--- a/src/libsystemd/sd-bus/bus-internal.h
+++ b/src/libsystemd/sd-bus/bus-internal.h
@@ -298,6 +298,8 @@ struct sd_bus {
 
         sd_bus_message *current_message;
         sd_bus_slot *current_slot;
+        sd_bus_message_handler_t current_handler;
+        void *current_userdata;
 
         sd_bus **default_bus_ptr;
         pid_t tid;
diff --git a/src/libsystemd/sd-bus/bus-match.c b/src/libsystemd/sd-bus/bus-match.c
index 9e0769caa6..88b61a75be 100644
--- a/src/libsystemd/sd-bus/bus-match.c
+++ b/src/libsystemd/sd-bus/bus-match.c
@@ -294,11 +294,17 @@ int bus_match_run(
                         sd_bus_slot *slot;
 
                         slot = container_of(node->leaf.callback, sd_bus_slot, match_callback);
-                        if (bus)
+                        if (bus) {
                                 bus->current_slot = sd_bus_slot_ref(slot);
+                                bus->current_handler = node->leaf.callback->callback;
+                                bus->current_userdata = slot->userdata;
+                        }
                         r = node->leaf.callback->callback(bus, m, slot->userdata, &error_buffer);
-                        if (bus)
+                        if (bus) {
+                                bus->current_userdata = NULL;
+                                bus->current_handler = NULL;
                                 bus->current_slot = sd_bus_slot_unref(slot);
+                        }
 
                         r = bus_maybe_reply_error(m, r, &error_buffer);
                         if (r != 0)
diff --git a/src/libsystemd/sd-bus/bus-objects.c b/src/libsystemd/sd-bus/bus-objects.c
index 78dab8048d..03604091ec 100644
--- a/src/libsystemd/sd-bus/bus-objects.c
+++ b/src/libsystemd/sd-bus/bus-objects.c
@@ -51,7 +51,9 @@ static int node_vtable_get_userdata(
         u = s->userdata;
         if (c->find) {
                 bus->current_slot = sd_bus_slot_ref(s);
+                bus->current_userdata = u;
                 r = c->find(bus, path, c->interface, u, &u, error);
+                bus->current_userdata = NULL;
                 bus->current_slot = sd_bus_slot_unref(s);
 
                 if (r < 0)
@@ -123,7 +125,9 @@ static int add_enumerated_to_set(
                 slot = container_of(c, sd_bus_slot, node_enumerator);
 
                 bus->current_slot = sd_bus_slot_ref(slot);
+                bus->current_userdata = slot->userdata;
                 r = c->callback(bus, prefix, slot->userdata, &children, error);
+                bus->current_userdata = NULL;
                 bus->current_slot = sd_bus_slot_unref(slot);
 
                 if (r < 0)
@@ -273,7 +277,11 @@ static int node_callbacks_run(
                 slot = container_of(c, sd_bus_slot, node_callback);
 
                 bus->current_slot = sd_bus_slot_ref(slot);
+                bus->current_handler = c->callback;
+                bus->current_userdata = slot->userdata;
                 r = c->callback(bus, m, slot->userdata, &error_buffer);
+                bus->current_userdata = NULL;
+                bus->current_handler = NULL;
                 bus->current_slot = sd_bus_slot_unref(slot);
 
                 r = bus_maybe_reply_error(m, r, &error_buffer);
@@ -388,7 +396,11 @@ static int method_callbacks_run(
                 slot = container_of(c->parent, sd_bus_slot, node_vtable);
 
                 bus->current_slot = sd_bus_slot_ref(slot);
+                bus->current_handler = c->vtable->x.method.handler;
+                bus->current_userdata = u;
                 r = c->vtable->x.method.handler(bus, m, u, &error);
+                bus->current_userdata = NULL;
+                bus->current_handler = NULL;
                 bus->current_slot = sd_bus_slot_unref(slot);
 
                 return bus_maybe_reply_error(m, r, &error);
@@ -427,7 +439,9 @@ static int invoke_property_get(
         if (v->x.property.get) {
 
                 bus->current_slot = sd_bus_slot_ref(slot);
+                bus->current_userdata = userdata;
                 r = v->x.property.get(bus, path, interface, property, reply, userdata, error);
+                bus->current_userdata = NULL;
                 bus->current_slot = sd_bus_slot_unref(slot);
 
                 if (r < 0)
@@ -489,7 +503,9 @@ static int invoke_property_set(
         if (v->x.property.set) {
 
                 bus->current_slot = sd_bus_slot_ref(slot);
+                bus->current_userdata = userdata;
                 r = v->x.property.set(bus, path, interface, property, value, userdata, error);
+                bus->current_userdata = NULL;
                 bus->current_slot = sd_bus_slot_unref(slot);
 
                 if (r < 0)
diff --git a/src/libsystemd/sd-bus/bus-slot.c b/src/libsystemd/sd-bus/bus-slot.c
index 5e927511d5..d6793c29e9 100644
--- a/src/libsystemd/sd-bus/bus-slot.c
+++ b/src/libsystemd/sd-bus/bus-slot.c
@@ -245,3 +245,23 @@ _public_ sd_bus_message *sd_bus_slot_get_current_message(sd_bus_slot *slot) {
 
         return slot->bus->current_message;
 }
+
+_public_ sd_bus_message_handler_t sd_bus_slot_get_current_handler(sd_bus_slot *slot) {
+        assert_return(slot, NULL);
+        assert_return(slot->type >= 0, NULL);
+
+        if (slot->bus->current_slot != slot)
+                return NULL;
+
+        return slot->bus->current_handler;
+}
+
+_public_ void* sd_bus_slot_get_current_userdata(sd_bus_slot *slot) {
+        assert_return(slot, NULL);
+        assert_return(slot->type >= 0, NULL);
+
+        if (slot->bus->current_slot != slot)
+                return NULL;
+
+        return slot->bus->current_userdata;
+}
diff --git a/src/libsystemd/sd-bus/sd-bus.c b/src/libsystemd/sd-bus/sd-bus.c
index 0fadd1699e..83233fd7e6 100644
--- a/src/libsystemd/sd-bus/sd-bus.c
+++ b/src/libsystemd/sd-bus/sd-bus.c
@@ -2102,7 +2102,11 @@ static int process_timeout(sd_bus *bus) {
 
         bus->current_message = m;
         bus->current_slot = sd_bus_slot_ref(slot);
+        bus->current_handler = c->callback;
+        bus->current_userdata = slot->userdata;
         r = c->callback(bus, m, slot->userdata, &error_buffer);
+        bus->current_userdata = NULL;
+        bus->current_handler = NULL;
         bus->current_slot = sd_bus_slot_unref(slot);
         bus->current_message = NULL;
 
@@ -2194,7 +2198,11 @@ static int process_reply(sd_bus *bus, sd_bus_message *m) {
         }
 
         bus->current_slot = sd_bus_slot_ref(slot);
+        bus->current_handler = c->callback;
+        bus->current_userdata = slot->userdata;
         r = c->callback(bus, m, slot->userdata, &error_buffer);
+        bus->current_userdata = NULL;
+        bus->current_handler = NULL;
         bus->current_slot = sd_bus_slot_unref(slot);
 
         if (slot->floating) {
@@ -2235,7 +2243,11 @@ static int process_filter(sd_bus *bus, sd_bus_message *m) {
                         slot = container_of(l, sd_bus_slot, filter_callback);
 
                         bus->current_slot = sd_bus_slot_ref(slot);
+                        bus->current_handler = l->callback;
+                        bus->current_userdata = slot->userdata;
                         r = l->callback(bus, m, slot->userdata, &error_buffer);
+                        bus->current_userdata = NULL;
+                        bus->current_handler = NULL;
                         bus->current_slot = sd_bus_slot_unref(slot);
 
                         r = bus_maybe_reply_error(m, r, &error_buffer);
@@ -2512,7 +2524,11 @@ static int process_closing(sd_bus *bus, sd_bus_message **ret) {
 
                 bus->current_message = m;
                 bus->current_slot = sd_bus_slot_ref(slot);
+                bus->current_handler = c->callback;
+                bus->current_userdata = slot->userdata;
                 r = c->callback(bus, m, slot->userdata, &error_buffer);
+                bus->current_userdata = NULL;
+                bus->current_handler = NULL;
                 bus->current_slot = sd_bus_slot_unref(slot);
                 bus->current_message = NULL;
 
@@ -3113,6 +3129,18 @@ _public_ sd_bus_slot* sd_bus_get_current_slot(sd_bus *bus) {
         return bus->current_slot;
 }
 
+_public_ sd_bus_message_handler_t sd_bus_get_current_handler(sd_bus *bus) {
+        assert_return(bus, NULL);
+
+        return bus->current_handler;
+}
+
+_public_ void* sd_bus_get_current_userdata(sd_bus *bus) {
+        assert_return(bus, NULL);
+
+        return bus->current_userdata;
+}
+
 static int bus_default(int (*bus_open)(sd_bus **), sd_bus **default_bus, sd_bus **ret) {
         sd_bus *b = NULL;
         int r;