bus: synthesize local error reply when we cannot deliver a message to kdbus because...

[elogind.git] / src / libsystemd-bus / bus-kernel.c

diff --git a/src/libsystemd-bus/bus-kernel.c b/src/libsystemd-bus/bus-kernel.c
index 8a0f0859766858ebd54bbfef72c35cdcc88b52a4..69143434b3cf9729f085a25f699552a328d678d0 100644 (file)
--- a/src/libsystemd-bus/bus-kernel.c
+++ b/src/libsystemd-bus/bus-kernel.c
@@ -365,11 +365,7 @@ int bus_kernel_take_fd(sd_bus *b) {
         /* the kernel told us the UUID of the underlying bus */
         memcpy(b->server_id.bytes, hello.id128, sizeof(b->server_id.bytes));
 
-        r = bus_start_running(b);
-        if (r < 0)
-                return r;
-
-        return 1;
+        return bus_start_running(b);
 }
 
 int bus_kernel_connect(sd_bus *b) {
@@ -397,13 +393,60 @@ int bus_kernel_write_message(sd_bus *bus, sd_bus_message *m) {
         assert(m);
         assert(bus->state == BUS_RUNNING);
 
+        /* If we can't deliver, we want room for the error message */
+        r = bus_rqueue_make_room(bus);
+        if (r < 0)
+                return r;
+
         r = bus_message_setup_kmsg(bus, m);
         if (r < 0)
                 return r;
 
         r = ioctl(bus->output_fd, KDBUS_CMD_MSG_SEND, m->kdbus);
-        if (r < 0)
-                return errno == EAGAIN ? 0 : -errno;
+        if (r < 0) {
+                _cleanup_bus_error_free_ sd_bus_error error = SD_BUS_ERROR_NULL;
+                sd_bus_message *reply;
+
+                if (errno == EAGAIN || errno == EINTR)
+                        return 0;
+                else if (errno == ENXIO || errno == ESRCH) {
+
+                        /* ENXIO: unique name not known
+                         * ESRCH: well-known name not known */
+
+                        if (m->header->type == SD_BUS_MESSAGE_METHOD_CALL)
+                                sd_bus_error_setf(&error, SD_BUS_ERROR_SERVICE_UNKNOWN, "Destination %s not known", m->destination);
+                        else
+                                return 0;
+
+                } else if (errno == EADDRNOTAVAIL) {
+
+                        /* EADDRNOTAVAIL: activation is possible, but turned off in request flags */
+
+                        if (m->header->type == SD_BUS_MESSAGE_METHOD_CALL)
+                                sd_bus_error_setf(&error, SD_BUS_ERROR_SERVICE_UNKNOWN, "Activation of %s not requested", m->destination);
+                        else
+                                return 0;
+                } else
+                        return -errno;
+
+                r = bus_message_new_synthetic_error(
+                                bus,
+                                BUS_MESSAGE_SERIAL(m),
+                                &error,
+                                &reply);
+
+                if (r < 0)
+                        return r;
+
+                r = bus_seal_synthetic_message(bus, reply);
+                if (r < 0)
+                        return r;
+
+                bus->rqueue[bus->rqueue_size++] = reply;
+
+                return 0;
+        }
 
         return 1;
 }
@@ -448,55 +491,18 @@ static int push_name_owner_changed(sd_bus *bus, const char *name, const char *ol
 
         m->sender = "org.freedesktop.DBus";
 
-        r = bus_seal_message(bus, m);
-        if (r < 0)
-                return r;
-
-        r = bus_rqueue_push(bus, m);
+        r = bus_seal_synthetic_message(bus, m);
         if (r < 0)
                 return r;
 
+        bus->rqueue[bus->rqueue_size++] = m;
         m = NULL;
-        return 1;
-}
-
-static int push_name_name_acquired(sd_bus *bus, const char *signal, const char *name) {
-        _cleanup_bus_message_unref_ sd_bus_message *m = NULL;
-        int r;
-
-        assert(bus);
-
-        r = sd_bus_message_new_signal(
-                        bus,
-                        "/org/freedesktop/DBus",
-                        "org.freedesktop.DBus",
-                        signal,
-                        &m);
-
-        if (r < 0)
-                return r;
-
-        r = sd_bus_message_append(m, "ss", name);
-        if (r < 0)
-                return r;
-
-        m->sender = "org.freedesktop.DBus";
-
-        r = bus_seal_message(bus, m);
-        if (r < 0)
-                return r;
-
-        r = bus_rqueue_push(bus, m);
-        if (r < 0)
-                return r;
 
-        m = NULL;
         return 1;
 }
 
 static int translate_name_change(sd_bus *bus, struct kdbus_msg *k, struct kdbus_item *d) {
         char new_owner[UNIQUE_NAME_MAX], old_owner[UNIQUE_NAME_MAX];
-        int r;
 
         assert(bus);
         assert(k);
@@ -505,19 +511,6 @@ static int translate_name_change(sd_bus *bus, struct kdbus_msg *k, struct kdbus_
         if (d->name_change.flags != 0)
                 return 0;
 
-        /* First generate NameAcquired/NameList messages */
-        if (d->type == KDBUS_ITEM_NAME_ADD && d->name_change.new_id == bus->unique_id) {
-                r = push_name_name_acquired(bus, "NameAcquired", d->name_change.name);
-                if (r < 0)
-                        return r;
-
-        } else if (d->type == KDBUS_ITEM_NAME_REMOVE && d->name_change.old_id == bus->unique_id) {
-                r = push_name_name_acquired(bus, "NameLost", d->name_change.name);
-                if (r < 0)
-                        return r;
-        }
-
-        /* Then, generate NameOwnerChanged messages */
         if (d->type == KDBUS_ITEM_NAME_ADD)
                 old_owner[0] = 0;
         else
@@ -566,15 +559,13 @@ static int translate_reply(sd_bus *bus, struct kdbus_msg *k, struct kdbus_item *
 
         m->sender = "org.freedesktop.DBus";
 
-        r = bus_seal_message(bus, m);
-        if (r < 0)
-                return r;
-
-        r = bus_rqueue_push(bus, m);
+        r = bus_seal_synthetic_message(bus, m);
         if (r < 0)
                 return r;
 
+        bus->rqueue[bus->rqueue_size++] = m;
         m = NULL;
+
         return 1;
 }
 
@@ -877,12 +868,9 @@ static int bus_kernel_make_message(sd_bus *bus, struct kdbus_msg *k) {
         m->kdbus = k;
         m->release_kdbus = true;
         m->free_fds = true;
-
         fds = NULL;
 
-        r = bus_rqueue_push(bus, m);
-        if (r < 0)
-                goto fail;
+        bus->rqueue[bus->rqueue_size++] = m;
 
         return 1;
 
@@ -909,12 +897,7 @@ int bus_kernel_read_message(sd_bus *bus) {
 
         assert(bus);
 
-        /* Kernel messages might result in 2 new queued messages in
-         * the worst case (NameOwnerChange and LostName for the same
-         * well-known name, for example). Let's make room in
-         * advance. */
-
-        r = bus_rqueue_make_room(bus, 2);
+        r = bus_rqueue_make_room(bus);
         if (r < 0)
                 return r;